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Dissertations / Theses on the topic 'Ultraviolet detection'
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Pauchard, Alexandre. "Silicon sensor microsystem for ultraviolet detection /." Lausanne, 2000. http://library.epfl.ch/theses/?nr=2152.
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Mahon, Alexandra Rose. "Ultraviolet absorption detection of DNA in gels." Thesis, Imperial College London, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.298204.
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Short, Billy Joe. "Ultraviolet resonance Raman enhancements in the detection of explosives." Thesis, Monterey, Calif. : Naval Postgraduate School, 2009. http://edocs.nps.edu/npspubs/scholarly/theses/2009/Jun/09Jun%5FShort.pdf.
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Thesis (M.S. in Applied Physics)--Naval Postgraduate School, June 2009.Thesis Advisor(s): Smith, Craig F. "June 2009." Description based on title screen as viewed on 14 July 2009. Author(s) subject terms: Raman spectroscopy, standoff detection, high explosives, explosive detection, inelastic scattering, resonance Raman. Includes bibliographical references (p. 77-80). Also available in print.
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McCaughrean, Mark J. "The astronomical application of infrared array detectors." Thesis, University of Edinburgh, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.380441.
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Diale, Mmantsae Moche. "Schottky barrier diode fabrication on n-GaN for ultraviolet detection /." Access to E-Thesis, 2009. http://upetd.up.ac.za/thesis/available/etd-02112010-211125/.
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Urmi, Nusrat Jahan. "Cryptosporidium capture and detection of ultraviolet radiation induced DNA damage." Thesis, University of British Columbia, 2017. http://hdl.handle.net/2429/61058.
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Majority of the waterborne outbreaks in USA and Canada are associated with protozoa. Cryptosporidium, an obligate intra-cellular human pathogen, is responsible for more than 50% of these outbreaks and has become one of the major public health concerns as they can survive typical chemical disinfection treatments. Early detection of this parasite in the water and determination of ultraviolet treatment efficacy can play a role in reducing this disease burden.
An antibody based capture surface was developed to detect Cryptosporidium oocysts in treated water. The surface was able to capture three different species of Cryptosporidium: C. parvum; C. muris; C. hominis but not E. coli indicating that the capture surface is Cryptosporidium genus specific rather than species specific and the chances of capturing microorganisms other than Cryptosporidium from water are low. IgG3 was selected as better candidate for the capture surface development due to its higher capture efficiency (~84%-90%) compared to that of IgG1 (~54%-74%). Though the oocysts were successfully released in intact form from the capture surface at pH 1.0, it was not possible to reuse the surface because the capture performance decreased after pH treatment.
An indirect ELISA protocol was optimized to detect UV induced photoproducts (CPDs) in the DNA of UV treated Cryptosporidium oocysts using cuvettes in a spectrophotometer. Power soil kit was selected as the preferred DNA extraction kit because of its high recovery from low concentration of Cryptosporidium in water with high concentrations of other solids. The optimized ELISA protocol was applied on the samples spiked with different doses (0, 3, 6, 10 and 40 mJ/cm²) of UV irradiated Cryptosporidium oocysts. The signal generated from DNA-antibody reaction resulted in an exponential rise to maximum curve which showed that the absorbance (indication of DNA damage) increased with the increase in UV dose. Adaptation of these techniques for Cryptosporidium detection & UV treatment validation is expected to improve the standards for water quality monitoring, providing the communities with assurance that their water is safe to consume.Irving K. Barber School of Arts and Sciences (Okanagan)
Biology, Department of (Okanagan)
Graduate
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Ariyawansa, Gamini. "Semiconductor Quantum Structures for Ultraviolet-to-Infrared Multi-Band Radiation Detection." Digital Archive @ GSU, 2007. http://digitalarchive.gsu.edu/phy_astr_diss/17.
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In this work, multi-band (multi-color) detector structures considering different semiconductor device concepts and architectures are presented. Results on detectors operating in ultraviolet-to-infrared regions (UV-to-IR) are discussed. Multi-band detectors are based on quantum dot (QD) structures; which include quantum-dots-in-a-well (DWELL), tunneling quantum dot infrared photodetectors (T-QDIPs), and bi-layer quantum dot infrared photodetectors (Bi-QDIPs); and homo-/heterojunction interfacial workfunction internal photoemission (HIWIP/HEIWIP) structures. QD-based detectors show multi-color characteristics in mid- and far-infrared (MIR/FIR) regions, where as HIWIP/HEIWIP detectors show responses in UV or near-infrared (NIR) regions, and MIR-to-FIR regions. In DWELL structures, InAs QDs are placed in an InGaAs/GaAs quantum well (QW) to introduce photon induced electronic transitions from energy states in the QD to that in QW, leading to multi-color response peaks. One of the DWELL detectors shows response peaks at ∼ 6.25, ∼ 10.5 and ∼ 23.3 µm. In T-QDIP structures, photoexcited carriers are selectively collected from InGaAs QDs through resonant tunneling, while the dark current is blocked using AlGaAs/InGaAsAlGaAs/ blocking barriers placed in the structure. A two-color T-QDIP with photoresponse peaks at 6 and 17 µm operating at room temperature and a 6 THz detector operating at 150 K are presented. Bi-QDIPs consist of two layers of InAs QDs with different QD sizes. The detector exhibits three distinct peaks at 5.6, 8.0, and 23.0 µm. A typical HIWIP/HEIWIP detector structure consists of a single (or series of) doped emitter(s) and undoped barrier(s), which are placed between two highly doped contact layers. The dual-band response arises from interband transitions of carriers in the undoped barrier and intraband transitions in the doped emitter. Two HIWIP detectors, p-GaAs/GaAs and p-Si/Si, showing interband responses with wavelength thresholds at 0.82 and 1.05 µm, and intraband responses with zero response thresholds at 70 and 32 µm, respectively, are presented. HEIWIP detectors based on n-GaN/AlGaN show an interband response in the UV region and intraband response in the 2-14 µm region. A GaN/AlGaN detector structure consisting of three electrical contacts for separate UV and IR active regions is proposed for simultaneous measurements of the two components of the photocurrent generated by UV and IR radiation.
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Creeden, Jason Andrew. "Growth Engineering And Characterization Of Vanadium Dioxide Films For Ultraviolet Detection." W&M ScholarWorks, 2020. https://scholarworks.wm.edu/etd/1593091709.
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There is a need for efficient ultraviolet (UV) detectors in many fields, such as aerospace, automotive manufacturing, biology, environmental science, and defense, due to photomultiplier tubes (the currently available technology) often not meeting application constraints in weight, robustness, and power consumption. In my thesis, I demonstrate that high quality vanadium dioxide (VO2) thin films, epitaxially grown on niobium doped titanium dioxide substrates (TiO2:Nb), display a strong photoconductive response in the UV spectral range, making them promising candidates for photomultiplier-free UV photodetection. By adjusting the characteristics of the substrate and VO2 film, the samples achieve external quantum efficiency exceeding 100% (reaching beyond 1,000% for optimized samples) superior to that of current wide band gap UV detectors at room temperature. The mechanism for photocurrent production in VO2/TiO2:Nb heterostructure is a space-charge region, engineered in the heterojunction, yielding favorable conditions for hole tunneling from TiO2:Nb into VO2. Improving upon the heterostructure, I demonstrate up to an order of magnitude improvement in parameters such as responsivity, external quantum efficiency, detectivity, and dark current density by applying Au films to the VO2/TiO2:Nb heterostructure. Ultimately, my work proved that the VO2/TiO2:Nb heterostructure is a promising alternative technology for UV detection in high demand fields, with great potential for scalable device production.
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Surugau, Noumie. "Peptide separations using capillary electrophoresis with single point and imaging ultraviolet detection." Thesis, University of York, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.434159.
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George, Ronie. "Early Ovarian Cancer Detection Using Fluorescence Spectroscopy in the Ultraviolet-C through Visible." Diss., The University of Arizona, 2013. http://hdl.handle.net/10150/301694.
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We evaluate the changes in fluorescence from endogenous fluorophores such as amino acids, structural proteins and enzymatic co-factors to predict malignancy and risk of developing ovarian cancer. 249 ovarian biopsies of the surface epithelium were interrogated in vitro, over 270-550 nm excitation, and fluorescence was collected from 290-700nm. Spectroscopic data was analyzed using parallel factor analysis (PARAFAC) to determine excitation and emission spectra of the underlying fluorophores that contribute to the total detected fluorescence intensity. Using multivariate normal distribution fits and cross-validation techniques, sensitivity (SN) and specificity (SP) of 88 and 93 percent, respectively, were achieved when classifying malignant samples versus others, while 88 and 80 percent, respectively, were achieved when classifying normal post menopausal patients as being either at low- or high-risk of developing ovarian cancer based on their personal and family history of cancer. Also, the performance of classifying cancer increases when the normal group excludes benign neoplasm and endometriosis samples, while the performance of low- v. high-risk decreases when both pre- and post-menopausal samples are included. These results could potentially be useful in screening women at increased risk of developing ovarian cancer. This motivated our study to investigate similar changes in ovarian autofluorescence in vivo. 40 patients were recruited and a total of 189 samples were imaged using a fiber optic bundle and biopsied. Using PARAFAC, the factors computed from in vitro data analysis and in vitro data as a training set; pathology from each in vivo site biopsied was compared to calibrated tissue-fluorescence. It resulted in a SN and SP of 100 and 94 percent, respectively, for classifying normal versus malignant. In the case of risk assessment, cross validated in vivo data gave a SN and SP of 68 and 93%. Results obtained were consistent with those obtained in vitro, except for the presence of blood absorption peaks which affected risk assessment. Assessing endogenous fluorescence has diagnostic potential and if adapted to trans-vaginal access, would make the screening procedure less costly and less invasive, and would be most useful and economical in women at increased risk of developing ovarian cancer and might determine the ideal time to undergo an oophorectomy.
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Zhu, Ming. "An Immobolized Surfactant Extraction Technique Compatible with High Performance Liquid Chromatography-Ultraviolet Visible Detection." TopSCHOLAR®, 1999. http://digitalcommons.wku.edu/theses/765.
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Surfactant mediated extractions are analogous to liquid-liquid extractions (LLE) except surfactants are used as extractants instead of organic solvents. The benefit for using surfactants for extractions includes lower toxicity, lower associated costs and direct compatibility with high performance liquid chromatography techniques. In this study, a novel immobilized surfactant extraction method was developed. In this method, the cationic alklytrimethylamrnonium surfactants are immobilized onto a strong cationic exchange resin through ion exchange. This surfactant-resin material is placed in a column and aqueous solutions containing analytes are passed through. The analytes are retained by the long carbon chain of the surfactant molecules and by the sulfonic acid group site on the cationic resin. By adding saturated sodium chloride solution, the resin is converted into the sodium form, and the analytes and surfactant molecules subsequently elute from the column. The solution is collected. By adding an appropriate amount of cosurfactant to the solution, a biphasic solution forms, consisting of aqueous and surfactant rich layers. Almost all the surfactant molecules trapped with analytes will move to the upper surfactant rich phase. The analytes are concentrated in this manner. An aliquot of the surfactant-rich phase is then injected into a high performance liquid chromatograph for analysis. In this research work, the surfactant molecules were confirmed to be bounded on ion exchange resin readily. The relationship between the amount of surfactant bounded on resin and the exchange reaction time was determined. The resin mesh size, resin pretreating time, and sample flow rate were investigated. The effectiveness of this procedure was tested using seven chlorophenols as trace samples. The recoveries for selected chlorophenols were as high as 90 percent. The detection limits were as low as 10-parts-per billion. The effect of water hardness on the extraction efficiency was also investigated. The possible mechanism of this novel extraction technique is discussed.
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Eckhardt, Hanns Simon. "Gas analysis in the deep ultraviolet wavelength region using fibre-optics and spectrophotometric detection." Thesis, City, University of London, 2009. http://openaccess.city.ac.uk/19753/.
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Diale, M. (Mmantsae Moche). "Schottky barrier diode fabrication on n-GaN for altraviolet detection." Thesis, University of Pretoria, 2010. http://hdl.handle.net/2263/28143.
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There are many potential areas for the utilization of GaN-based nitride materials, including ultraviolet photodetectors. Ultraviolet photodetectors are used in the military for missile plume detection and space communications. Medically, ultraviolet photodiodes are used in monitoring skin cancer. Schottky barrier metal-semiconductor contacts are choice devices for the manufacture of ultraviolet photodiodes due to higher short wavelength sensitivity and fast response. They also require simple fabrication technology; suffer lower breakdown voltages, and record larger leakage currents at lower voltages as compared to p-n structures of the same semiconductor material. Thus the formation of a Schottky contact with high barrier height, low leakage current, and good thermal stability in order to withstand high temperature processing and operation are some of the most important factors in improving the performance of Schottky barrier photodiodes to be used for ultraviolet detection. The first stage of this study was to establish a chemical cleaning and etching technique. It was found that KOH was suitable in reducing C from the surface and that (NH4)2S further reduced the surface oxides. The next phase of the work was to select a metal that will allow UV light to pass through at a high transmission percentage: a combination of annealed Ni/Au was found to be ideal. The transmission percentage of this alloy was found to be above 80%. The next phase was the fabrication of Ni/Au Schottky barrier diodes on GaN to study the electrical characteristics of the diodes. Electrical characterization of the diodes showed that the dominant current transport mechanism was thermionic emission, masked by the effects of series resistance, which resulted from the condition of the GaN surface. Finally, we fabricated GaN UV photodiodes and characterized them in the optoelectronic station designed and produced during this research. Device responsivity as high as 31.8 mA/W for GaN and 3.8 mA/W for AlGaN were recorded. The calculated quantum efficiencies of the photodiodes were 11 % for GaN and 1.7 % for AlGaN respectively.Thesis (PhD)--University of Pretoria, 2010.
Physics
unrestricted
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Bränström, Richard. "Skin cancer prevention : behaviours related to sun exposure and early detection /." Stockholm, 2003. http://diss.kib.ki.se/2003/91-7349-550-6/.
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Newkirk, Scott Hunter. "Detection levels of drinking water contaminants using field portable ultraviolet and visible light (uv/vis) spectrophotometry /." Download the thesis in PDF, 2005. http://www.lrc.usuhs.mil/dissertations/pdf/NEWKIRK2005.pdf.
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Marino, Stephen A. "Operation and calibration of the NPS Ultraviolet Imaging Spectrometer (NUVIS) in the detection of sulfur dioxide plumes." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 1999. http://handle.dtic.mil/100.2/ADA373307.
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Thesis (M.S. in Applied Physics) Naval Postgraduate School, December 1999."December 1999". Thesis advisor(s): David S. Davis, Richard C. Olsen. Includes bibliographical references (p. 91-92). Also available online.
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Forney, Bryan J. "Spectral analysis of ultraviolet clutter sources to improve probability of detection in helicopter UV missile warning systems." Monterey, Calif. : Naval Postgraduate School, 2008. http://edocs.nps.edu/npspubs/scholarly/theses/2008/Dec/08Dec%5FForney.pdf.
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Thesis (M.S. in Applied Physics)--Naval Postgraduate School, December 2008.Thesis Advisor(s): Millsaps, Knox T. ; Haegel, Nancy M. "December 2008." Description based on title screen as viewed on January 29, 2009. Includes bibliographical references (p. 141-146). Also available in print.
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Wakefield, Clare Helen. "The remote detection of uranium leaks using fluorescence characteristics." Thesis, University of Salford, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.313871.
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Lamarca, Rafaela Silva. "Desenvolvimento de uma metodologia analítica para determinação de ácidos fenólicos em amostras de azeite de dendê (Elaeis guineensis) por HPLC com detecção simultânea no UV e eletroquímica (homemade)." Universidade Federal de Juiz de Fora, 2015. https://repositorio.ufjf.br/jspui/handle/ufjf/1552.
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As substâncias fenólicas têm se tornado objeto de investigação, devido aos inúmeros benefícios à saúde humana e a influência na qualidade alimentícia. Neste trabalho determinou-se os ácidos fenólicos presentes no azeite de dendê, de fabricação artesanal e industrializado. Para estas análises utilizou-se um cromatógrafo líquido de alta eficiência (HPLC Agilent 1100 series), injetor manual com válvula Rheodyne de 20μL, coluna de fase Reversa C18 Inertsil ODS-3, coluna de guarda Inertsil ODS, detector UV-VIS de múltiplos comprimentos de ondas (UV-VIS MWD). Ao canal de resíduos do HPLC foi adaptada uma célula eletroquímica, com capacidade de 1,00 mL, sendo esta composta por três eletrodos: eletrodo de trabalho, carbono vítreo; eletrodo de referência, Ag/AgCl (KCl,sat) e eletrodo auxiliar de aço inox. As medidas eletroquímicas foram realizadas em um potenciostato μAutolab type III, conectado a um microcomputador, utilizando o software GPES 4.9. As análises foram realizadas de forma simultânea em ambos detectores, em uma mesma injeção. A fase móvel otimizada foi capaz de separar os analitos totalmente, sendo esta composta pela mistura uma solução aquosa de H3PO4 pH 2,40 + NaClO4 a 7 mmol.L-1/isopropanol (87:13 v/v), por eluição isocrática. O comprimento de onda utilizado na detecção UV foi 225 nm. As medidas amperométricas foram realizadas no potencial de +1,1 V para todos os analitos. A recuperação das amostras foi realizada através da padronização interna, utilizando o ácido o-cumárico como padrão interno (PI) e o ácido m-cumárico como padrão surrogate (PS). A recuperação do PS foi superior a 75% em ambos detectores para todas as amostras. Os limites instrumentais para detecção UV variaram de 0,019 (ácido siríngico) a 0,029 mg.L-1 (ácido ferúlico) e de quantificação 0,063 (ácido siríngico) a 0,095 mg.L-1 (ácido sinápico); já para a detecção eletroquímica (DE) os limites de detecção encontraram-se na faixa de 0,015 (ácido p-cumárico) a 0,079 mg.L-1(ácido ferúlico) e os de quantificação 0,050 (ácido p-cumárico) a 0,27 mg.L-1(ácido ferúlico). As concentrações dos ácidos fenólicos nas amostras de azeite de dendê de fabricação artesanal, variaram de 0,12 a 10,3 mg.L-1 (detecção UV) e de 1,0 a 11,0 mg.L-1 (DE). Já as concentrações obtidas nas amostras de azeite de dendê industrializadas variaram de 0,21 a 14,7 mg.L-1 (detecção UV) e de 3,0 a 11,9 mg.L-1 (DE). O sistema HPLC-UV-DE mostrou-se promissor nas análises dos ácidos fenólicos nestas e em outras matrizes complexas.
Phenolic substances have become the subject of investigation due to the numerous benefits to human health and the influence in the food quality. In this work, the phenolic acids in homemade and industrialized palm oil were determined. For these analyzes, it was used a high performance liquid chromatograph (HPLC Agilent 1100 series) with a manual 20μL Rheodyne valve, a reverse phase column C18 Inertsil ODS-3, a guard column Inertsil ODS and a UV-VIS detector for multiple wavelengths (UV-VIS MWD). At the end of HPLC waste channel was adapted an electrochemical cell with a capacity of 1.00 mL, with a standard three-electrode configuration, consisting of glassy carbon working electrode, a Ag/AgCl (KCl, sat) reference electrode and stainless steel needle as counter electrode. The electrochemical measurements were made using a μAutolab type III potentiostat, with its data acquisition software (GPES 4.9 version). The detections were performed sequentially, in the same injection. The optimal mobile phase was able to completely separate the analytes by isocratic elution, being composed of an aqueous solution of H3PO4 pH 2.40, containing 7mmol.L-1 of NaClO4 /isopropanol (87:13 v/v). The wavelength used for the UV detection was 225 nm. The amperometric measurements were performed at +1.1 V for all analytes. The recovery of the samples was performed using internal standardization, using o-coumaric acid as internal standard (PI) and m-coumaric acid as standard surrogate (PS). The recovery of PS was over 75% on both detectors for all samples. The instrumental limits for UV detection ranged from 0.019 (syringic acid) to 0.029 mg L-1 (ferulic acid) and quantification limits from 0.063 (syringic acid) to 0.095 mg L-1 (sinapic acid). In the same way, for electrochemical detection (ED) the instrumental limits was found in the range of 0.015 (p-coumaric acid) at 0.079 mg L-1 (ferulic acid), and the quantification limits were between 0.050 (p-coumaric acid) and 0.27 mg L-1 (ferulic acid). The concentration of phenolic acids in homemade palm oil samples ranged from 0.12 to 10.3 mg L-1 (UV detection) and from 1.0 to 11.0 mg L-1 (ED). The concentrations obtained in the industrialized palm oil samples varied from 0.21 to 14.7 mg L-1 (UV detection) and from 3.0 to 11.9 mg L-1 (ED). The HPLC-UV-ED system has shown promise in the analysis of these phenolic acids in this and other complex matrices.
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Choy, Man Hon. "Investigation of the effects of the 1) UV absorbance of halide ions and 2) wall adsorption of marker ions for indirect detection in capillary electrophoresis." HKBU Institutional Repository, 2001. http://repository.hkbu.edu.hk/etd_ra/286.
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Lin, Shu-Ling. "Electric Field Gradient Focusing-UV Detection for Protein Analysis." Diss., CLICK HERE for online access, 2006. http://contentdm.lib.byu.edu/ETD/image/etd1372.pdf.
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Ndube, Ncediwe. "Determination of fumonisins in maize by High Performance Liquid Chromatography with fluorescence and ultraviolet detection of o-phthaldialdehyde, naphthalene-2,3-dicarboxaldehyde and dansyl chloride derivatives." Thesis, University of the Western Cape, 2011. http://etd.uwc.ac.za/index.php?module=etd&action=viewtitle&id=gen8Srv25Nme4_2588_1320667169.
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Fumonisins, carcinogenic mycotoxins produced by various Fusarium species, occur naturally in maize and maize-based food products. They are hazards for animal and human health as they cause cancer in rodents and have been associated with oesophageal cancer and neural tube defects in humans. The most abundant naturally occurring fumonisins analogues in maize are fumonisin B1, B2 and B3 (FB1, FB2 and FB3). For analytical determination, they mostly require suitable extraction, clean-up and pre or post-column derivatization together with reversed-phase HPLC separation. o- Phthaldialdehyde (OPA) had been adopted as the most widely used derivatization reagent for fumonisins as they lack useful chromophores or fluorophores. Alternative derivatization reagents, naphthalene-2,3- dicarboxaldehyde (NDA) and dansyl chloride (DnS-Cl), were investigated in this study
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Pickering, M., and Stacy D. Brown. "Development and Validation of a High-Performance Liquid Chromatography with Ultraviolet Detection (HPLC-UV) Method for the Quantification of Ertapenem in Human Plasma." Digital Commons @ East Tennessee State University, 2011. https://dc.etsu.edu/etsu-works/5290.
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BRITO, Kal-El Basílio. "Extração de atributos de fáculas de imagens ultravioletas de isoladores poliméricos." Universidade Federal de Campina Grande, 2017. http://dspace.sti.ufcg.edu.br:8080/jspui/handle/riufcg/404.
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Capes
Em inspeção, com câmara sensível à radiação ultravioleta, são fornecidas apenas informações acerca do local onde estão concentradas as descargas corona e uma estimativa de intensidade dessas decargas em equipamento de alta tensão. Nesse intuito, uma metodologia de extração de atributos das fáculas de imagens ultravioletas de isoladores poliméricos de 230 kV foi desenvolvida. Para isso, foram usados vídeos captados pela câmera de detecção ultravioleta como material. Essas informações, quando adequadamente dispostas, podem servir de entrada a um sistema de auxílio à tomada de decisão que poderá classificar, finalmente, os isoladores em padrões predefinidos. Na metodologia do trabalho, desenvolveram-se várias rotinas de processamento digital de imagens para, inicialmente, adequar as imagens e, posteriormente, quantificar os atributos de interesse extraídos. As rotinas de adequação de imagens buscam segmentar o shape do isolador do plano de fundo, segmentar em uma imagem as fáculas, que representam descargas causadas pelo efeito corona, integralizar as fáculas de vários quadros em apenas uma imagem, eliminar o que vier a ser considerado ruído e segmentar o shape do isolador em partes de interesse. As rotinas de quantificação de atributos são destinadas a calcular a área, o perímetro, o fator de forma e a persistência das fáculas, além de sua distância às partes de interesse do isolador polimérico de 230 kV. Como resultado do desenvolvimento das rotinas, é apresentado um algoritmo para extração de atributos de fáculas. Finalmente, é feita uma análise de sensibilidade dos parâmetros usados no algoritmo no intuito de delimitar suas condições de uso. Dois estudos da aplicação do algoritmo foram realizados, em que, para cada um deles foram processados 64 combinações de número de quadros e de limite de ruído. Foram apresentadas as superfícies dos atributos de área, perímetro, fator de forma e persistência das fáculas em função dos dois parâmetros citados. A fim de determinar qual par ordenado (número de quadros, limite de ruído) seria adequado, adotou-se como métrica buscar o menor valor de gradiente das superfícies dos atributos. Concluiu-se que a metodologia de extração de atributos de fáculas de imagens ultravioletas de isoladores, para aprimoramento da classificação de isoladores foi desenvolvida com sucesso e a contribuição do trabalho se apresenta na metodologia para extração de atributos e na determinação do número de quadros e limite de ruído adequados para vídeos ultravioletas.
On inspection with ultraviolet sensitive camera, it is only supplied information on where the corona discharges are concentrated and an estimative of intensity of these discharges in high voltage equipment. For this purpose, it was developed a methodology of faculae attribute extraction of ultraviolet images from 230 kV polymeric insulators. In order to do this, videos captured by the ultraviolet detection camera were used as work material. The methodology of the work consists of the development of several digital image processing routines, initially, to adapt images and, later, to quantify the attributes of interest extracted. The image adaptation routines seek to segment the shape of the insulator from the background, to segment in an image the faculae that represent discharges caused by corona effect, to integrate faculae from multiple frames in only one image, to eliminate what is to be considered noise and to segment the shape of the insulator into parts of interest. The attribute quantification routines are destined for faculae area, perimeter, form factor and persistence, in addition to their distances of the 230 kV polymeric insulator parts of interest. As a result of the development of these routines an algorithm for attribute extraction is presented. Finally, a sensitivity analysis of the parameters used in the algorithm is made, with the intention to delimit its use conditions. Two case studies of the application of the algorithm were performed, for each of them 64 combinations of number of frames and noise limit were processed. Presenting the surfaces of area, perimeter, shape factor and persistence of the faculae attributes in function of the two cited parameters. In order to determine which number of frames and noise limit would be suitable, it was adopted as metric to look for the lowest gradient value of the attributes surfaces. In conclusion the methodology for extracting attributes from the UV image faculae of insulators to improve the classification of insulators was successfully developed and the contribution of the work is presented in extracting attributes and determining suitable number of frames and noise limits for UV videos.
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Scheurer, Amber. "Assessing the viability of sol-gel nimgo films for solar blind detection." Honors in the Major Thesis, University of Central Florida, 2011. http://digital.library.ucf.edu/cdm/ref/collection/ETH/id/507.
Full textAbstract:
Wide bandgap semiconductors have been broadly investigated for their potential to detect and emit high energy ultraviolet (UV) photons. Advancements in deep UV optoelectronic materials would enable the efficient and affordable realization of many medical, industrial and consumer UV optical devices. The traditional growth method, vacuum deposition, is an extremely complicated and expensive process. Sol-gel processing dramatically simplifies facility requirements and can be scaled to industrial size. The work presented here involves a novel study of the ternary wide bandgap material Ni1-xMgxO. Films were developed by sol-gel spin coating for investigation of material and electrical properties. This method produced films 200-600 nm thick with surface roughness below 4 nm RMS. Sintered films indicated an improvement from 60% to 90% transmission near the band edge. Additionally, compositional analysis was performed by X-ray Photoelectron Spectroscopy and film defects were characterized by photoluminescence using a continuous wave He-Cd UV laser, revealing the expected oxygen defect at 413nm. This film growth technique has produced thin polycrystalline films with low surface roughness and a high degree of crystalline orientation; crucial characteristics for semiconductor devices. These films have demonstrated the ability to be tuned over the full compositional range from the bandgap of NiO (3.6 eV) to that of MgO (7.8 eV). Optoelectronic devices produced by standard photolithographic techniques are discussed as well as the electrical transport properties of their metal contacts. Based on initial results, these films have demonstrated strong potential as solar blind detectors of UV radiation.B.S.E.E.
Bachelors
Engineering and Computer Science
Electrical Engineering
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Lien, Wan-Fu. "Separation of Transition Metal Ions by HPLC, Using UV-VIS Detection." Thesis, North Texas State University, 1987. https://digital.library.unt.edu/ark:/67531/metadc501145/.
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HPLC has been used and can quickly determine several ions simultaneously. The method of determination described for transition metals [Cr(III), Fe(III), Ni(II), Co(II), Cu(II), Zn(II), Cd(II), Mn(II)] and [Ca(II), Pb(II)] using HPLC with UV-VIS detection is better than the PAR complexation method commonly used. The effects of both eluent pH and detector wavelength were investigated. Results from using different pHs and wavelengths, optional analytical conditions for the separation of [Ni(II), Co(II), Cu(II)], [Cr(III), Fe(III), Ca(II), Ni(II), Cu(II)], and [Ca(II), Zn(II), Pb(II)] in one injection, respectively, are described. The influence of adding different concentrations of Na_2EDTA solvent to the sample is shown. Detection limits, linear range, and the comparisons between this study and a post-column PAR method are given.
27
Zakeri, Banafshe [Verfasser], and Sebastian [Akademischer Betreuer] Schlücker. "Label-free and site-specic detection of protein recognition by supramolecular ligands in solution using ultraviolet resonance Raman spectroscopy / Banafshe Zakeri ; Betreuer: Sebastian Schlücker." Duisburg, 2018. http://d-nb.info/1169572006/34.
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Daguet, Valérie. "Etude des méthodes de détection des radicaux libres : évaluation des effets des radiations ultraviolettes sur les protéines de la peau." Paris 5, 1995. http://www.theses.fr/1995PA05P132.
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Salazar, Fernanda Rodrigues. "Determinação de fármacos antidepressivos em leite materno." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2016. http://hdl.handle.net/10183/159544.
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O uso de fármacos durante a lactação é uma prática comum; porém, os tratamentos farmacológicos impõem grandes dúvidas tanto aos profissionais quanto às nutrizes sobre a segurança do uso destes durante este período. A amamentação é uma forma de vínculo entre mãe e bebê e está associada a diversos benefícios nutricionais, imunológicos, cognitivos, psicoafetivos, econômicos e sociais. A depressão é um problema clínico importante durante o período pós-parto, e a vulnerabilidade para o início ou recorrência de sintomas depressivos aumenta a possibilidade de uso de psicofármacos enquanto ocorre a lactação. Os antidepressivos inibidores seletivos da recaptação da serotonina são comumente prescritos para o tratamento destes quadros depressivos, entre eles fluoxetina, sertralina, citalopram e paroxetina, sendo que a maioria destes é excretada no leite materno e há grande variabilidade na quantidade de analitos que pode ser recebida pelo lactente. Bupropiona é um fármaco antidepressivo utilizado para o tratamento do tabagismo e quadros depressivos e tem sua excreção ao leite materno relatada em literatura. Métodos bioanalíticos para determinação da excreção de fármacos antidepressivos foram desenvolvidos e validados por cromatografia líquida acoplada a espectrômetro de massas e cromatografia líquida com detecção ultravioleta. Estes métodos demonstraram serem seletivos, lineares, precisos e exatos, com limites de quantificação de 5 ng/mL (fluoxetina, citalopram e bupropiona) e 20 ng/mL (sertralina e paroxetina) para método por LC-MS e de 200 ng/mL para todos os analitos no método por CLAE-UV. As amostras de leite materno foram coletadas em Banco de Leite de mães que declararam utilizar fluoxetina ou sertralina ou paroxetina e analisados. Os dados de concentração encontrados para os fármacos referidos estão dentro da faixa encontrada em literatura confirmando sua excreção no leite materno. Paroxetina apresentou valores abaixo do limite de quantificação. Das concentrações encontradas no leite materno, foram estimadas as doses absolutas e relativas no lactante, sendo que os resultados demonstraram baixos valores em relação a estas estimativas, podendo os fármacos analisados ser considerados seguros para manutenção do uso durante a lactação. Foi também detectada nas análises por LC-MS a presença de norfluoxetina, metabólito da fluoxetina, confirmando sua excreção nesta matriz.The use of medications during lactation is a common practice; however pharmacological treatments impose serious doubts to both, professionals and nursing mothers, about the safety of drugs use during this period. Breastfeeding is a natural form of bonding between mother and baby and it is associated with many nutritional, immunological, cognitive, psychoemotional, social and economic benefits. Depression is a major clinical problem during the postpartum period and the vulnerability to onset or recurrence of depressive symptoms increases the possibility of psychotropic drug use during lactation. Selective inhibitors of serotonin reuptake are commonly prescribed for the treatment of depressive disorders, including fluoxetine, sertraline, citalopram and paroxetine. Most of these drugs are excreted in breast milk and there is great variability in the amount of analytes that can be received by the infant. Bupropion is an antidepressant used for tabagism treatment and for depression symptoms; it is also described in literature its excretion into breast milk. Bioanalytical methods for determining the excretion of antidepressants were developed and validated by liquid chromatography coupled to mass spectrometry and liquid chromatography with ultraviolet detection. These methods proved to be selective, linear, precise and accurate with quantification limits of 5 ng/mL (fluoxetine, citalopram e bupropion) and 20 ng/mL (sertraline e paroxetine) for LC-MS method and 200 ng/mL for all analytes in the CLAE-UV method. Human milk samples were collected in milk banks from mothers to which the antidepressants fluoxetine or sertraline or paroxetine were administered, and the concentrations in this matrix were verified. Found concentrations were within the range described in the literature confirming their excretion in the breast milk. Paroxetine presented values less than limit of quantification. From the found concentrations, the absolute and relative doses in nursing were estimated. The results showed low values for these estimates and so the analyzed drugs can be considered safe to continue use during lactation. The presence of norfluoxetine, a metabolite of fluoxetine, was also detected by LC-MS, confirming its excretion in this matrix.
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Quiret, Samuel. "Circum galactic medium emission : from modeling to detection by a dedicated UV space mission." Thesis, Aix-Marseille, 2016. http://www.theses.fr/2016AIXM4735/document.
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L’évolution des galaxies est un sujet relativement débattu en astronomie extra-galactique, étant donné que la plupart des mécanismes responsables des propriétés observées dans les galaxies (masse, taux de formation d’étoiles, contenu en métaux, moment angulaire) sont encore peu contraints et certains ne sont probablement même pas encore observés. Ma thèse porte sur une analyse de la région entourant les galaxies, connue sous le nom de Milieu Circum Galactique (MCG). Le MCG est à l’interface entreles galaxies et le Milieu Inter Galactique (MIG) et est considéré comme le lieu de prédilection pour les échanges gazeux et énergétiques entre les galaxies et le MIG, ce qui en fait la clé pour une meilleure compréhension de l’évolution des galaxies et du destin des baryons. Je présenterai dans un premier temps l’analyse d’un échantillon de systèmes à forte absorption issuent de la spectroscopie de quasars en absorption qui tracent les régions denses en hydrogène généralement associées au MCG des galaxies.Dans un deuxième temps, je présenterai ma contribution au développement d’une mission ballon embarquant un spectrographe UV, FIREBall-2, spécialement conçu pour observer l’émission faible et diffuse du MCG des galaxies à décalage vers le rouge inférieur à 1. D’un point de vue technique, je présenterai l’étude du composant optique clé de l’instrument: le réseau. D’un point de vue modélisation, je décrirai une simulation complète des observations, qui servira à la préparation du vol prévu pour l’Automne 2017notamment en ce qui concerne la sélection des cibles, la stratégie observationelle et le traitement des donnéesThe evolution of galaxies is a rather hot topic in extra galactic astronomy, as many of the main mechanisms underlying the observed properties of galaxies (mass, star formation rate, metal content, angular momentum) are still poorly constraints and many of them are probably undiscovered yet. My thesis focuses on an analysis of the region surrounding galaxies, known as the Circum Galactic Medium (CGM). The CGMinterfaces the galaxy with the Inter Galactic Medium (IGM) and is thought to be the most active location for gas and energy exchanges (in and out), which makes it a key ingredient towards a better understanding of galaxy evolution and the fate of all baryons. I will present in a first part, the analysis of a sample of strong absorption features based on quasar absorption spectroscopy, that probe the dense neutral hydrogen usually associated with galaxies’ CGM. In a second part, I will present my contribution to the development of a balloon-borne UV spectrograph, FIREBall-2, specifically designed to observe the faint and diffuse emissions from the CGM of galaxies at redshifts below 1. On the technical side, I will present the characterization of the key optical component ofthe instrument: the grating. On the modeling side, I will focus on an end-to-end pixel simulation of the observations to prepare for the upcoming flight, planned for Autumn 2017, in terms of target selection, observational strategy and data analysis
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TOBIAS, CARMEN C. B. "Detectores gasosos de eletrodo resistivo: regime estacionario e transitorio de funcionamento." reponame:Repositório Institucional do IPEN, 2004. http://repositorio.ipen.br:8080/xmlui/handle/123456789/11235.
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Made available in DSpace on 2014-10-09T12:49:48Z (GMT). No. of bitstreams: 0Made available in DSpace on 2014-10-09T14:02:20Z (GMT). No. of bitstreams: 1 09811.pdf: 7739701 bytes, checksum: 322f7fce8713f27550b470eff5575b73 (MD5)
Tese (Doutoramento)
IPEN/T
Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP
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Leite, Rodrigo de Souza. "Análises de bisfosfonatos por cromatografia líquida de troca aniônica, detecção indireta no ultravioleta e por condutividade com supressão de eluente." Universidade de São Paulo, 2008. http://www.teses.usp.br/teses/disponiveis/75/75132/tde-10122008-171830/.
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Este trabalho apresenta o desenvolvimento de metodologias cromatográficas para a análise de Bisfosfonatos em medicamentos acabados, matérias-prima e em fluidos biológicos utilizando Cromatografia Iônica com detecção Indireta no UV e detecção por Condutividade com Supressão de Eluente. No capítulo 1, descreve-se a pesquisa bibliográfica das propriedades farmacológicas dos BP´s, suas principais rotas sintéticas e sobre os métodos analíticos apresentados na literatura científica. No capítulo 2, foi descrito o desenvolvimento de um método para a determinação dos BP´s etidronato, clodronato, pamidronato e alendronato em matéria-prima e para medicamentos de alendronato, utilizando Cromatografia Iônica e detecção indireta no Ultravioleta. A metodologia foi validada e aplicada na análise de medicamentos contendo alendronato em comprimidos de referência e em comprimidos genéricos. No capítulo 3, descreve-se estudos visando a determinação de etidronado em plasma humano, utilizando Cromatografia Iônica Multidimensional com detecção indireta no Ultravioleta. No capítulo 4, foi desenvolvida outra metodologia para a determinação do BP´s etidronato, clodronato, pamidronato e alendronato em matéria-prima e em medicamentos contendo alendronato, utilizando Cromatografia Iônica e detecção por Condutividade com supressão de eluente. A metodologia foi validada e aplicada na análise de medicamentos contendo alendronato em comprimidos similares e em comprimidos manipulados. No capítulo 5, uma metodologia utilizando Cromatografia Iônica e detecção por Condutividade com supressão de eluente foi desenvolvida e validada para determinar clodronato em urina humana.This work presents the development of chromatografic methodologies for analysis of Bisphosphonates in drugs, raw material and biological fluids using Ion Chromatography with indirect UV detection and conductivity detection with eluent suppression. In chapter 1, an extensive bibliographical research was accomplished in relationship to the pharmacological properties of bisphosphonates, their more important synthetic routes and about the analytical methods presented in the scientific literature. In chapter 2, the development of a method was described for the determination of BP´s etidronate, clodronate, pamidronate and alendronate in raw material and for alendronate tablets, using Ionic Chromatography with indirect UV detection. The methodology was applied to the analysis of medicines containing alendronate in both forms, generic and reference. In chapter 3, studies conducted to determinate etidronate in human plasma, using Multidimensional ionic chromatography with indirect UV detection are decribed. In chapter 4, a methodology developed for the determination of etidronate, clodronate, pamidronate and alendronate in raw material and for alendronate tablets using ionic chromatography and detection for conductivity with eluente suppression is described. The methodology was applied in the analysis of medicines with alendronate generic and reference. In chapter 5, a methodology using ion chromatography and detection for conductivity with eluente suppression was developed and validated to determine clodronate in human urine.
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Boutwell, Ryan. "The Impact of Growth Conditions on Cubic ZnMgO Ultraviolet Sensors." Doctoral diss., University of Central Florida, 2013. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/5908.
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Cubic Zn1-xMgxO (c-Zn1-xMgxO) thin films have opened the deep ultraviolet (DUV) spectrum to exploration by oxide optoelectronic devices. These extraordinary films are readily wet-etch-able, have inversion symmetric lattices, and are made of common and safe constituents. They also host a number of new exciting experimental and theoretical challenges. Here, the relation between growth conditions of the c-Zn1-xMgxO film and performance of fabricated ultraviolet (UV) sensors is investigated.
Plasma-Enhanced Molecular Beam Epitaxy was used to grow Zn1-xMgxO thin films and formation conditions were explored by varying the growth temperature, Mg source flux, oxygen flow rate, and radio-frequency (RF) power coupled into the plasma. Material review includes the effect of changing conditions on the film's optical transmission, surface morphology, growth rate, crystalline phase, and stoichiometric composition. Oxygen plasma composition was investigated by spectroscopic analysis under varying oxygen flow rate and applied RF power and is correlated to device performance. Ni/Mg/Au interdigitated metal-semiconductor-metal detectors were formed to explore spectral responsivity and UV-Visible rejection ratio (RR).
Zn1-xMgxO films ranged in Mg composition from x = 0.45 - 1.0. Generally, x increased with increasing substrate temperature and Mg source flux, and decreased with increasing oxygen flow rate and RF power. Increasing x was correlated with decreased peak responsivity intensity and increased RR. Device performance was improved by increasing the ratio of O to O+ atoms and minimizing O2+ in the plasma. Peak responsivity as high as 500 A/W was observed in visible-blind phase-segregated Zn1-xMgxO devices, while cubic phase solar-blind devices demonstrated peak responsivity as high as 12.6 mA/W, and RR of three orders of magnitude. Optimal conditions are predicted for the formation of DUV Zn1-xMgxO sensors.Ph.D.
Doctorate
Optics and Photonics
Optics and Photonics
Optics
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Bazkir, Ozcan. "Realization Of Detector Based Spectral Responsivity Scale From Ultraviolet To Near Infrared Regions Of Electromagnetic Spectrum." Phd thesis, METU, 2004. http://etd.lib.metu.edu.tr/upload/2/12605148/index.pdf.
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Realization of spectral responsivity scale was studied in three stages. Firstly, absolute optical power measurements using Electrical Substitution Cryogenic Radiometer (ESCR) was studied. The absolute measurements were done at discrete laser wavelengths of tunable Ar+ (488 nm and 514.5 nm), Nd:YAG (532 nm) and fixed He-Ne (632.8 nm) laser sources. To increase measurement accuracy the method used for the stabilization of laser beams, transmittance measurements of optical windows, and minimization of scattered beams were discussed.
Secondly, realization of absolute responsivity scale between 350- 850 nm ranges was studied. The scale based on reflection type trap detectors consisting of three silicon photodiodes. Various measurement systems were established in order to make optical characterization of trap detectors like non-linearity, surface non-homogeneity, polarization dependency, reflectance, and internal quantum efficiency. The absolute responsivity was linked to the absolute optical power by measuring the current response of trap detectors to the absolute power measured by ESCR system at laser wavelengths. Using models for the trap detector&rsquos, reflectance and internal quantum efficiency the scale between 350- 850 nm ranges was realized with an uncertainty of 0.05 %. Finally, the spectral responsivity scale in ultraviolet (UV) and near-infrared (NIR) regions was realized using Electrically Calibrated Pyroelectric Radiometer (ECPR). Optically characterizing the spatial non-uniformity of pyroelectric detector and its surface reflectance, the spectral responsivity scale was established with uncertainties ±
0.5-1.0 % between 250 nm and 350 nm and ±
0.5-1.5 % between 850 and 2500 nm.
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Zheng, Jun. "Supercritical Fluid Chromatography of Ionic Compounds." Diss., Virginia Tech, 2005. http://hdl.handle.net/10919/29519.
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Addition of a small amount of polar solvent (i.e. modifier) which contains an ionic component (i.e. additive) to a CO2 mobile phase has shown major improvement in the elution of ionic analytes via packed column supercritical fluid chromatography (SFC).
Firstly, we focused on the elution of sodium arylsulfonate analytes by using various ionic additives, such as lithium acetate, ammonium acetate, tetramethylammonium acetate, tetrabutylammonium acetate, and ammonium chloride. The analytes were successfully eluted with all additives with good peak shape under isocratic/isobaric/isothermal conditions. Three stationary phases with different degrees of deactivation were considered. They were conventional Cyanopropyl, Deltabond Cyanopropyl, and non-chemically bonded silica. The effect of additive concentration and additive functionality on retention was also investigated.
Secondly, solid state NMR of the silica packing material before and after being flushed with supercritical CO2 modified by methanol containing the ionic additives was performed to gain some insight into the retention mechanism(s). A fraction of silanol protons were undetected after being treated with the mobile phase which suggested replacement by the cationic component of the additive. CaChe calculations were carried out on several of the additives in an attempt to explain why different ionic additives produce different effects on chromatographic retention. Modification of the stationary phase and ion pairing with the analyte are two possible retention mechanisms being considered.
As ion-pair formation was considered to be one of the retention mechanisms, the use of sodium sulfonates as mobile phase additives to elute secondary and quaternary ammonium salts was then studied. Propranolol HCl, benzyltrimethylammonium chloride, and cetylpyridium chloride were chosen as the probe analytes. Sodium ethansulfonate, sodium 1-heptanesulfonate, and sodium 1-decanesulfonate were studied as mobile phase additives. The analytes were successfully eluted from Deltabond Cyano phase within 5 minutes, but were retained strongly without additive or with ammonium acetate as the additive. An Ethylpyridine column showed dramatic advantages on the elution of these ammonium analytes. No additive was required to elute these ionic compounds. Protonation of some fraction of the pyridine functional groups and the deactivation of active silanol sites were believed to be the major mechanisms responsible for this behavior.
Lastly, we successfully eluted large peptides (up to 40 mers) containing a variety of acidic and basic residues in SFC. We used trifluoroacetic acid as additive in a CO2/methanol mobile phase to suppress deprotonation of peptide carboxylic acid groups and to protonate peptide amino groups. The Ethylpyridine column was used for the majority of this work. The relatively simple mobile phase was compatible with mass spectrometric (MS) detection. To our knowledge, this is the first report of the elution of peptides of this size with a simple, MS-compatible mobile phase. Fast analysis speed, the possibility of coupling multiple columns to achieve desired resolution, a normal-phase retention mechanism, and less use of organic solvents are the advantages of SFC approach for peptide separation.Ph. D.
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Araújo, Mariele Brambilla de. "Caracterização físico-química, desenvolvimento e validação de métodos analíticos para o extrato seco dos bulbos da espécie Rhodophiala bifida (Herb.) Traub com alto teor do alcaloide Montanina." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2017. http://hdl.handle.net/10183/170688.
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Os alcaloides têm apresentado diversas atividades biológicas. Entre eles, a montanina vem demonstrando um bom desempenho nesse sentido, como, atividade antioxidante, ação inibitória do crescimento de culturas bacterianas e importante atividade de inibição do crescimento de linhagens tumorais. Atualmente, não existem muitos relatos da sua caracterização ou métodos analíticos quantitativos disponíveis na literatura para atribuir seu teor. Assim, após purificação, a caracterização da montanina foi realizada por calorimetria exploratória diferencial (DSC), espectroscopia na região do ultravioleta (UV), infravermelho (IV), espectrometria de massas (CLAE-EM), ressonância magnética nuclear de hidrogênio (RMN1H), de carbono (RMN13C) e em 2D homo e heteronucleares tais como COSY (nJH-H, escalar), NOESY (nJH-H, dipolar), HSQC (1JH-C, escalar) e HMBC (nJH-C, escalar). Na sequência, foram desenvolvidos métodos empregando a cromatografia líquida de alta eficiência (CLAE) acoplada aos detectores ultravioleta e aerossol carregado (CLAE- UV/DAC) para a quantificação da montanina. Os mesmos foram validados, avaliando-se os parâmetros de especificidade, linearidade, intervalo, limite de detecção, limite de quantificação, precisão, exatidão e robustez. Os resultados obtidos foram avaliados por estatística descritiva e os métodos comparados pelo resultado da análise de variância (ANOVA). Desse modo, foram desenvolvidos procedimentos que podem ser aplicados para aprimorar o controle de qualidade, contribuindo para assegurar a eficácia terapêutica da montanina.Alkaloids have several biological activities. Among them, montanine have shown antioxidant activity, inhibitory effect on bacterial growth and important activity inhibiting growth of some tumor cell lines. Currently, there are a few reports about its characterization as well as quantitative analytical methods to determine its purity. Thus, after a purification step, montanine will be characterized by its differential scanning calorimetry (DSC), ultraviolet spectroscopy (UV), infrared spectroscopy (IR), mass spectrometry (HPLC-MS), nuclear magnetic resonance of proton (NMR1H), carbon (NMR13C) and 2D homo and heteronuclear such as COSY (nJH-H, scalar), NOESY (nJH-H, dipolar), HSQC (1JH-C, scalar) and HMBC (nJH-C, scalar). Further, quantitation methods will be developed employing high-performance liquid chromatography (HPLC) coupled with ultraviolet and charged aerosol detectors (HPLC-UV/CAD). These methods will be validated regarding the parameters specificity, linearity, range, detection limit, quantitation limit, precision, accuracy and robustness. The results will then be evaluated by descriptive statistics and the developed methods will be compared using analysis of variance (ANOVA). Therefore, tests will be developed that can be used to improve quality control, helping to ensure the therapeutic efficacy of montanine.
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Morajkar, Pranay P. "Application of laser photolysis coupled to time resolved optical detection methods to study the kinetics and spectroscopy of atmospherically relevant species." Thesis, Lille 1, 2012. http://www.theses.fr/2012LIL10063/document.
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Les radicaux OH et HO2 jouent un rôle essentiel dans beaucoup de processus d’oxydationdans l’atmosphère. La dégradation des composés organiques volatils dans les conditionstroposphériques est généralement initiée par la réaction avec les radicaux OH, suivie par la réactiondes produits d’oxydation avec l’oxygène. Dans le cadre de cette thèse, des études ont été menéesafin de mieux comprendre les mécanismes d’oxydation d’espèces d’intérêt atmosphérique. Pour cela,un système expérimental de photolyse laser couplée à des techniques spectroscopiques de détectionrésolues dans le temps : Continuous Wave Cavity ring-down Spectroscopy (cw-CRDS) pour HO2,Laser Induced Fluorescence (LIF) pour OH et spectroscopy UV pour l’adduit Hexamethylbenzene-OH(HMB-OH) ont été utilisés. Différents systèmes chimiques ont été étudiés en utilisant ce dispositif expérimental : 1) laréaction d’HO2 avec CH2O, 2) la photolyse à 248 nm de l’acétaldéhyde et 3) la dégradation de HMBinitiée par OH. Les techniques de cw-CRDS et d’absorption UV ont été utilisées respectivement pourmesurer les sections efficaces de CH2O et de l’adduit HMB-OHOH and HO2 radicals play a vital role in many oxidation processes in the atmosphere. Thedegradation of volatile organic compounds under tropospheric conditions is induced by reaction withhydroxyl radicals followed by the subsequent chemistry of the initial OH oxidation products with O2.This thesis deals with the kinetic study of some of these atmospherically relevant reactions to betterunderstand their oxidation mechanisms using experimental techniques such as laser photolysiscoupled to detection by Laser Induced Fluorescence (LIF, for OH), continuous wave- Cavity RingdownSpectroscopy (cw-CRDS, for HO2) and time resolved UV spectroscopy (UV, forHexamethylbenzene-OH adduct). Different chemical systems have been studied using the above techniques: 1) the reaction ofHO2 radicals with formaldehyde, 2) the 248 nm photolysis of acetaldehyde and 3) the OH initiatedoxidation of Hexamethyl benzene. In addition to this, the spectroscopic application of cw-CRDStechnique and UV spectroscopy has been used for the measurement of absorption cross section ofselected absorption lines of formaldehyde in the near infrared region and Hexamethylbenzene-OHadduct in the UV region respectively
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Lasmar, Marcelo Carvalho. "Determinação de ecstasy e derivados anfetamínicos em amostras de urina utilizando-se cromatografia líquida de alta eficiência com detecção de ultravioleta e em comprimidos utilizando-se cromatografia em fase gasosa com detector de ionização de chama." Universidade Federal de Minas Gerais, 2007. http://hdl.handle.net/1843/KMCG-72BK76.
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The abusive amphetamine use and its derivatives have shown a dramatic increasing in the last years in diverse regions of the world and Brazil, namely the special use of ecstasy (MDMA). These drugs are easily synthetized and commercialized with extreme discretion, what it strengthens the necessity of the development of forms of identification of these substances. A simple method, of easy execution and low financial cost, is proposed for identification and quantification of MDMA and its main metabolite (MDA) in human urine samples performed by high performance liquid chromatography UV detector. Identification and quantification of MDMA and others amphetamines derivatives (MDA and MDE) in tablets were also performed using gas chromatography flame ionization detector. The amphetamines derivatives are eluted in adjusted time and resolution. The optimized methods have shown adequate linearity, precision, selectivity and robustness, besides being capable to detect the analytes even when present in very little amount, not only in urine but also in tablets, being thus suitable to be adopted as confirmatory methods in forensic laboratories.O uso abusivo de anfetaminas e seus derivados vêm aumentando dramaticamente nos últimos anos em diversas regiões do mundo e do Brasil, notando-se especial utilização do ecstasy (MDMA). Essas drogas são facilmente sintetizadas e comercializadas com extrema discrição, o que reforça a necessidade do desenvolvimento de formas de identificação dessas substâncias. Um método simples, de fácil execução e baixo custo financeiro é proposto para identificação e quantificação de MDMA e seu principal metabólito (MDA) em amostras de urina humana utilizando-se cromatografia líquida de alta eficiência com detecção de ultravioleta. A identificação e quantificação de MDMA e outros derivados anfetamínicos (MDA e MDE) também foi realizada em comprimidos, utilizando-se cromatografia gasosa com detector de ionização em chama. Os derivados anfetamínicos são eluídos em tempo e resolução adequados. Os métodos otimizados apresentaram adequada linearidade, precisão, seletividade e robustez, além de serem capazes de detectarem os analitos mesmo quando presentes em pequenas concentrações, não somente na urina, mas também em comprimidos, sendo assim adequados para serem adotados como métodos confirmatórios em laboratórios forenses.
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Zheng, Xuqian. "Ultra-Wide Bandgap Crystals for Resonant Nanoelectromechanical Systems (NEMS)." Case Western Reserve University School of Graduate Studies / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=case1554765522327938.
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Brenac, Ariel. "Développements instrumentaux pour la photoémission inverse." Grenoble 1, 1987. http://www.theses.fr/1987GRE10010.
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Canon a electron fournissant un faisceau dans la gamme 5 ev-50 ev: resolution en vecteur d'onde de 0,2 a**(-1), courant maximal de 25 microamperes a 20 ev. Les spectres de photoemission inverse resolue angulairement presentent des effets angulaires a 30 ev. A 10 ev les effets angulaires devraient etre plus marques mais de faible rendement du spectrometre a cette energie rend les experiences difficiles. Caracterisation de nouvelles sources d'electrons: electrons emis par effet du champ par une cathode comprenant un grand nombre de micropointes. Ces cathodes fonctionnent a basse temperature. Description du spectrometre uv du vide et de la multidetection des photons
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Hu, Jun. "4H-SiC detectors for low level ultraviolet detection." 2008. http://hdl.rutgers.edu/1782.2/rucore10001600001.ETD.17497.
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CHAO-YUE, YANG, and 楊朝越. "Ultraviolet detection based on ZnO nanoparticles/graphene heterostructure." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/834n22.
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碩士國立臺南大學
材料科學系碩士班
107
This study successfully combines the electrical conductivity of graphene with the photoelectric properties of zinc oxide to fabricate a novel heterostructure for ultraviolet (UV) detection. Zinc oxide nanoparticles (ZnO NPs) with high ultraviolet (UV) sensitivity were grown on graphene across two electrodes to modulate the electron behavior in the graphene. A UV detector built in this way need only a voltage bias 0.01V. Due to the extremely thin characteristics of graphene, when UV is irradiated on the electrically insulated ZnO NPs above the graphene, the photogenerated electrons form a localized electrostatic field on the surface of the particles, which significantly suppressing the graphene current. This method is different from the conventional light detection mechanism of semiconductor, which as the light is illuminated, the photo current rises. The research result can provide an alternative for the light sensing technology.
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Beck, Ariane Laura 1979. "Wide band gap avalanche photodiodes for ultraviolet single photon detection." 2006. http://hdl.handle.net/2152/12995.
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LAI, YU-JHEN, and 賴芋蓁. "Separation of Histone by Capillary Electrophoresis with Ultraviolet-Visible Detection." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/t8u3bh.
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碩士東海大學
化學系
105
Histones are the basic structural units protein found in eukaryotic cell.They are highly basic amino acids which can interact with negatively charged phosphate groups in DNA. They are the chief protein components of chromatin, acting as spools around which DNA winds, and playing a role in gene regulation. Heterogeneity among cancer cells within individual tumors has emerged as a general feature of cancer,with critical implications for cancer diagnosis and treatment. That demonstrate a critical role for Histone H1.0 in inhibiting tumor maintenance. Here, we present standard protocols for acid extraction of histones from human liver cancer cells. Separation of five major families of histones include H1/H5, H2A, H2B, H3, and H4 with ultraviolet visible detection,and the detection wavelength is 280 nm. The separation condition of histone is Tris-Borate buffer add SDS (Sodium dodecyl sulfate),and the separation voltage is +15 kV. By changing the buffer solution concentration, pH value, and SDS concentration can improve the protein will be adsorbed on the surface of the capillary. By adding different concentrations of 250K Da hydroxyethyl cellulose, the best separation resolution can be obtained. Under through optimized experimental conditions and apparatus , it can separate the different kind of cancer cell include Nasopharyngeal carcinoma cells (TW02), cervical cancer cells (Hela), lung cancer cells (A549). We can explore the differences in histones between different cancer cells.
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Chiang, Yun-Li, and 姜云力. "Improved Ultraviolet Detection of ZnO Nanorod Photodetectors Using Graphene Flakes." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/48111058380304850053.
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碩士國立臺灣海洋大學
光電科學研究所
102
This thesis studies the improved ultraviolet photoconductor photodetectors (PDs) based on the ZnO nanorods (NRs) and grapheme (GP) (ZnO NRs/GP) composites. From the measurements of current-voltage relationship, photocurrent spectra and time-resolved photocurrent, we found that dark currents of pure ZnO RDs PD and ZnO NRs/GP composites PD were 4.641#westeur024#10-7 A and 2.947#westeur024#10-7 A, respectively, with a 37 % reduction after the addition of GP for ZnO RDs PD. The photocurrent of pure ZnO RDs PD and ZnO NRs/GP composites PD were 1.263#westeur024#10-5 A and 6.221#westeur024#10-5 A, respectively, with a 5 times enhancement after the addition of GP for ZnO RDs PD. The photoconductor gain increased from 27.23 to 211.1, with a 7.7 times enhancement. The ultraviolet-visible rejection ratio increased from 24.8 to 51.6, with a 2.1 times enhancement. The response time decreased from 32.3 s to 16.4 s, with a 50 % reduction. The recovery time decreased from 13.1 s to 5.2 s, with a 60 % reduction. According to the results, the addition of GP can decrease the dark current and increase the photocurrent for ZnO RDs PDs. Therefore, the photoconductor gain increased substantially. The response time and the recovery time of ZnO NRs/GP PDs decreased also. From the measurements of scanning electron microscopy, photoluminescence and absorption spectra, we speculated that the increase in photocurrent and photoconductor gain may be due to the addition of GP for ZnO RDs PD. This study shows the ZnO NRs/GP composites can improve the performance of the ZnO UV photodetectors.
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Bartz, Jeffrey Allan. "The ultraviolet photodissociation of organometallic molecules using vacuum ultraviolet photoionization and time-of-flight mass spectrometry for detection." 1992. http://catalog.hathitrust.org/api/volumes/oclc/28648749.html.
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Chen, Jyun-Wei, and 陳俊瑋. "Improving Ultraviolet Detection Performance of Nanostructured P-N Junction with Double Insulating Layers." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/536hh7.
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碩士國立中山大學
電機工程學系研究所
103
In this thesis, the nanostructed P-N heterojunction with double insulating layers applied to ultraviolet (UV) detecting applications has been well studied. ZnO and CuO films were deposited on silicon substrate sequentially to form the heterojunction by using the RF sputtering system. ZnO film is also a seed layer for growing the nanorod structure by hydrothermal method. ZnO nanorods can improve the device performance to UV. HfO2 thin films were deposited on both sides of P-N heterojunction as insulating layers to enhance the sensitivity. Aluminum electrodes were deposited on the insulating layers to form the Al/HfO2/CuO/ZnO/HfO2/Al device structure. The morphology of the ZnO nanorods is related to the hydrothermal reaction time and the reagent concentrations. All these surface structures are observed by scanning electron microscope (SEM) to analyze the effects on device performance. The results show that the device under 0.1M hydrothermal solution for growing 5 hours has the best sensitivity to UV radiation after an annealing process. The sensitivity, rise time and recovery time are 158.7%, 3 s and 4 s, respectively. Nanorod structure can help UV has more chances be absorbed by the ZnO. Annealing process reduces the defects in the material. Double insulating layers restrain the dark current and enhance the sensitivity. The research has a great potential for applying into ultraviolet index (UVI) detection and aerospace industry.
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Chou, Chen-Shiun, and 周辰勳. "Ultraviolet Irradiated ZnO-Nanorod Sensor for High Performance Oxygen Detection under Low Working Temperatures." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/00034463447166283321.
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碩士國立中山大學
機械與機電工程學系研究所
101
This work presents a novel ultraviolet irradiation assisted nanostructured ZnO film for high performance oxygen sensing under a low working temperature. Nanorod ZnO structures are synthesized on a glass substrate with interdigital sensing electrodes utilizing the developed two-stage sol-gel and hydrothermal processes. An 80 mW LED with the emission wavelength of 370 nm is then used to enhance the sensing performance of the nanostructured ZnO film. Results indicate that the sensing performance of the nano ZnO oxygen sensor is greatly improved. The oxygen sensor can work at a low temperature of 50˚C with the assist of UV exposure, which is much lower than the working temperature of typical solid state metal oxide sensors of around 350˚C. The response of the UV-assisted ZnO film shows 4.66 times larger than the same film without UV exposure. The method developed in the present study provides a simple yet high performance method for oxygen sensing under low operation temperature. ZnO has been used as the sensing material for oxygen or volatile organic compound (VOC) sensing. Typical solid state gas sensors rely on an operation temperature of 300 - 350˚C to enhance the carrier mobility of the metal oxide for sensing purpose. This approach usually consumes more energy for heating the sensing element and also significantly reduces the lifetime of the sensor. Alternatively, zinc oxide is II-VI group semiconductor with a wide band gap of 3.3 eV. UV exposure is an efficient way to produce hole-electron pairs in ZnO surface to enhance the sensing performance of ZnO-based gas sensor. With this approach, high operation temperature can be excluded for gas sensing. Adsorbed oxygen molecules will attract the UV induced electrons and form O2¯ due to the large electronegativity, resulting in the resistance incensement of the sensing layer due to the decease of electron carriers. A simplified process is used for producing the ZnO-based oxygen sensor. The sensing area for the nanostructured ZnO is 8.0 mm x 8.0 mm. The XRD patterns of the ZnO nanorods presents strong diffraction peak of (002) illustrates that the high tendency of ZnO nanorods growing along the c-axis. The SEM image shows the synthesized ZnO seed layer prior to the growth of nanorods. Ultra-fine ZnO nanospheres are about 15 nm on the substrate. The growth of the nanorods is preferred in the direction perpendicular to the substrate. The length of ZnO nanorods is about 600 nm. The measured response for sensing 97% oxygen is used various ZnO sensing layers with and without UV exposure at a low temperature of 50˚C. Results show that the nanorod ZnO film with the assist of UV exposure exhibits higher response. The response of UV-assisted ZnO nanorods was significantly higher than the same film without UV irradiation at all operation temperatures. The measured result of the 97% oxygen for three repeating tests evaluates the sensing repeatability of the developed sensor. The calculated variation for these three measurements was only 3.3%. The nice linearity (R2=0.9952) from 5 to 1000 mTorr confirms the good sensing performance of the developed sensor. Result also indicates that the detection limit of the sensor can be as low as 5 mTorr. The developed oxygen sensor utilizing UV-assisted ZnO nanorods has shown its potential to be a high performance oxygen sensor which can work at a low temperature.
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Liao, Fang-Yi, and 廖芳儀. "Determination of tranexamic acid coupled with chemical derivatization by capillary liquid chromatography with ultraviolet detection." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/07645677905464548997.
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碩士高雄醫學大學
香粧品學系碩士班
101
Tranexamic acid is a synthetic derivative of lysine. It is similar to lysine in structure that can use for the inhibition of plasminogen to plasmin, thereby reducing tyrosinase activity and melanin production. In addition to cosmetics uses, tranexamic acid is a medical antifibrinolytic drug used in haemorrhagic conditions and women menstrual blood loses. Because tranexamic acid lacks the chromophore, the derivatization steps are needed for determination of tranexamic acid at low concentration by UV detector. Compared with the previous literature, we chose dansyl chloride as the derivatizing reagent in this study, which had the advantages of the less sample used and stable derivatives. Furthermore we used microwave-assisted reaction to reduce the reaction time which made the operation more quickly. In order to prolong the life time of analytical column, we used dispersive liquid-liquid microextraction (DLLME) to extract excess derivatizing reagent by 4 μL chloroform. Compared with the traditional liquid-liquid extraction, the advantages of DLLME in this study were the less organic solvent used and reduced the waste generated. In this study, we were utilizing capillary liquid chromatography coupling with ultraviolet detector to monitor the dansyl derivative. The dynamic range was from 0.1 to 50 μM with a correlation coefficient 0.999 and the detection limit was 0.03 μM. The precision of intra- and interday were below 0.83 and 3.08%, respectively. Eventually, we were successfully applied this method to determine the content of tranexamic acid in pharmaceuticals, cosmetic products, the stratum corneum extractant and cell samples.
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Stubbs, C., J. M. Haigh, and I. Kanfer. "Determination of erythromycin in serum and urine by high performance liquid chromatography with ultraviolet detection." 1985. http://hdl.handle.net/10962/d1006576.
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A high-performance liquid chromatographic analysis of erythromycin in human serum and urine with UV detection at 200 nm is presented. The method involves a solid-phase extraction procedure followed by a simple phase separation step and chromatography on a reversed-phase column. The method has sensitivity limits of 0.25 and 1.0 g/mL in serum and urine, respectively, and is sufficiently sensitive to monitor concentrations of erythromycin in human serum and urine after the administration of a single 500-mg erythromycin stearate tablet.