Log in

Relevant bibliographies by topics / Velocity spectrometry / Journal articles

To see the other types of publications on this topic, follow the link: Velocity spectrometry.

Journal articles on the topic 'Velocity spectrometry'

Author: Grafiati

Published: 4 June 2021

Last updated: 2 February 2022

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles

Select a source type:

Consult the top 50 journal articles for your research on the topic 'Velocity spectrometry.'

Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.

You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.

Browse journal articles on a wide variety of disciplines and organise your bibliography correctly.

1

Kim, Myung Hwa, Brian D. Leskiw, Lei Shen, and Arthur G. Suits. "Velocity map imaging mass spectrometry." International Journal of Mass Spectrometry 252, no. 1 (2006): 73–78. http://dx.doi.org/10.1016/j.ijms.2006.01.030.

Full text

APA, Harvard, Vancouver, ISO, and other styles

2

Jacobsen, A. S., M. Salewski, J. Eriksson, et al. "Velocity-space sensitivity of neutron spectrometry measurements." Nuclear Fusion 55, no. 5 (2015): 053013. http://dx.doi.org/10.1088/0029-5515/55/5/053013.

Full text

APA, Harvard, Vancouver, ISO, and other styles

3

Srama, Ralf, Wolfgang Woiwode, Frank Postberg, et al. "Mass spectrometry of hyper-velocity impacts of organic micrograins." Rapid Communications in Mass Spectrometry 23, no. 24 (2009): 3895–906. http://dx.doi.org/10.1002/rcm.4318.

Full text

APA, Harvard, Vancouver, ISO, and other styles

4

Coghill, Peter J., Michael J. Millen, and Brian D. Sowerby. "On-Line Particle Size Analysis Using Ultrasonic Velocity Spectrometry." Particle & Particle Systems Characterization 14, no. 3 (1997): 116–21. http://dx.doi.org/10.1002/ppsc.199700024.

Full text

APA, Harvard, Vancouver, ISO, and other styles

5

Brouard, M., E. K. Campbell, A. J. Johnsen, C. Vallance, W. H. Yuen, and A. Nomerotski. "Velocity map imaging in time of flight mass spectrometry." Review of Scientific Instruments 79, no. 12 (2008): 123115. http://dx.doi.org/10.1063/1.3036978.

Full text

APA, Harvard, Vancouver, ISO, and other styles

6

Bull, James N., Jason W. L. Lee, Sara H. Gardiner, and Claire Vallance. "Account: An Introduction to Velocity-Map Imaging Mass Spectrometry (VMImMS)." European Journal of Mass Spectrometry 20, no. 2 (2014): 117–29. http://dx.doi.org/10.1255/ejms.1264.

Full text

APA, Harvard, Vancouver, ISO, and other styles

7

Winter, B., E. Halford, and M. Brouard. "Velocity corrected ion extraction in microscope mode imaging mass spectrometry." International Journal of Mass Spectrometry 356 (December 2013): 14–23. http://dx.doi.org/10.1016/j.ijms.2013.09.012.

Full text

APA, Harvard, Vancouver, ISO, and other styles

8

Li, Yu-Fan, Dong-Mei Zhao, Wen-Chang Zhou, et al. "Nonlinear response of phosphor screen used in velocity map imaging spectrometry." International Journal of Mass Spectrometry 442 (August 2019): 23–28. http://dx.doi.org/10.1016/j.ijms.2019.04.007.

Full text

APA, Harvard, Vancouver, ISO, and other styles

9

Gundlach-Graham, Alexander, Elise A. Dennis, Steven J. Ray, et al. "Laser-ablation sampling for inductively coupled plasma distance-of-flight mass spectrometry." Journal of Analytical Atomic Spectrometry 30, no. 1 (2015): 139–47. http://dx.doi.org/10.1039/c4ja00231h.

Full text

APA, Harvard, Vancouver, ISO, and other styles

10

Doms, Marco, and Jörg Müller. "Design, Fabrication, and Characterization of a Micro Vapor-Jet Vacuum Pump." Journal of Fluids Engineering 129, no. 10 (2007): 1339–45. http://dx.doi.org/10.1115/1.2776968.

Full text

Abstract:

A microelectromechanical system (MEMS) vapor-jet pump for vacuum generation in miniaturized analytical systems, e.g., micro-mass-spectrometers (Wapelhorst, E., Hauschild, J., and Mueller, J., 2005, “A Fully Integrated Micro Mass Spectrometer,” in Fifth Workshop on Harsh-Environment Mass Spectrometry;Hauschild, J., Wapelhorst, E., and Mueller, J., 2005, “A Fully Integrated Plasma Electron Source for Micro Mass Spectrometers,” in Ninth International Conference on Miniaturized Systems for Chemistry and Life Sciences (μTAS), pp. 476–478), is presented. A high velocity nitrogen or water vapor jet is used for vacuum generation. Starting from atmospheric pressure, a high throughput of more than 23ml∕min and an ultimate pressure of 495mbars were obtained with this new type of micropump. An approach for the full integration of all components of the pump is presented and validated by experimental results. The pump is fabricated from silicon and glass substrates using standard MEMS fabrication techniques including deep reactive ion etching, trichlorosilane molecular vapor deposition, and metal-assisted chemical etching for porous silicon fabrication. Micromachined pressure sensors based on the Pirani principle have been developed and integrated into the pump for monitoring.

APA, Harvard, Vancouver, ISO, and other styles

11

Månsson, Erik P., Vincent Wanie, Mara Galli, et al. "High-resolution mass spectrometry and velocity map imaging for ultrafast electron dynamics in complex biomolecules." EPJ Web of Conferences 205 (2019): 03007. http://dx.doi.org/10.1051/epjconf/201920503007.

Full text

Abstract:

We present a design combining a velocity map imaging electron spectrometer with a reflectron mass spectrometer. Since the two spectrometer sides have different intrinsic requirements for the electric field in the central region, a large number of electrodes and a reflectron-geometry of the mass spectrometer were employed to achieve simultaneous high resolutions. Together with femtosecond and attosecond pump-probe methods it will enable studies of ultrafast dynamics in large molecular systems.

APA, Harvard, Vancouver, ISO, and other styles

12

Poterya, Viktoriya, Dana Nachtigallová, Jozef Lengyel, and Michal Fárník. "Photodissociation of aniline N–H bonds in clusters of different nature." Physical Chemistry Chemical Physics 17, no. 38 (2015): 25004–13. http://dx.doi.org/10.1039/c5cp04485e.

Full text

Abstract:

The solvent effects on the photodissociation of aniline in cluster environments have been investigated by H-photofragment velocity map imaging at 243 nm, mass spectrometry after electron ionization, and ab initio calculations.

APA, Harvard, Vancouver, ISO, and other styles

13

Loo, R. Ogorzalek, G. E. Hall, H. P. Haerri, and P. L. Houston. "State-resolved photofragment velocity distributions by pulsed extraction time-of-flight mass spectrometry." Journal of Physical Chemistry 92, no. 1 (1988): 5–8. http://dx.doi.org/10.1021/j100312a002.

Full text

APA, Harvard, Vancouver, ISO, and other styles

14

Gustafson, Elaura L., Halle V. Murray, Tabitha Caldwell, and Daniel E. Austin. "Accurately Mapping Image Charge and Calibrating Ion Velocity in Charge Detection Mass Spectrometry." Journal of the American Society for Mass Spectrometry 31, no. 10 (2020): 2161–70. http://dx.doi.org/10.1021/jasms.0c00263.

Full text

APA, Harvard, Vancouver, ISO, and other styles

15

van der Heide, P. A. W. "Inverse velocity trends in secondary ion mass spectrometry; a new method for quantification?" Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms 86, no. 3-4 (1994): 373–79. http://dx.doi.org/10.1016/0168-583x(94)95303-1.

Full text

APA, Harvard, Vancouver, ISO, and other styles

16

Billings, Stephen, and Jens Hovgaard. "Modeling detector response in airborne gamma‐ray spectrometry." GEOPHYSICS 64, no. 5 (1999): 1378–92. http://dx.doi.org/10.1190/1.1444643.

Full text

Abstract:

A geometrical detector model of airborne gamma‐ray spectrometry is presented for data acquired using a rectangular detector of arbitrary dimensions. The detector response is modeled by calculating variations in solid angle and detector thickness for sources at different orientations. This gives the total count rate, which is then multiplied by a factor, assumed independent of orientation, to give the peak count rate. The model shows excellent agreement with experimental data collected using a 4.2-liter detector and with Monte Carlo simulations of a 16.8-liter detector. Results for the 4.2-liter crystal showed significant asymmetry. However, for a typical airborne system, with a 16.8-liter crystal, the asymmetry was weak because the detector had about the same solid angle and thickness at any azimuthal angle. The point spread function for the geometrical detector model differed significantly from a uniform detector model, the latter predicting a lower spatial resolution. This implies that surveys designed on the uniform assumption may undersample the signal between flight lines. For example, at 60 m elevation, the area that contributes 90% of the thorium signal is predicted to be 10.9 hectares (ha) for the uniform model and only 7.6 ha for the geometrical model. The model can be extended to incorporate aircraft velocity by convolving the stationary model with a rectangular function. Aircraft velocity can have a substantial influence on the modeled response if long integration times permit significant displacement of sources relative to the height of the aircraft.

APA, Harvard, Vancouver, ISO, and other styles

17

Shuai, P., X. Xu, Y. H. Zhang, et al. "An improvement of isochronous mass spectrometry: Velocity measurements using two time-of-flight detectors." Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms 376 (June 2016): 311–15. http://dx.doi.org/10.1016/j.nimb.2016.02.006.

Full text

APA, Harvard, Vancouver, ISO, and other styles

18

Wittmaack, K. "The ‘infinite velocity method’: a means of concentration calibration in secondary ion mass spectrometry?" Surface Science 429, no. 1-3 (1999): 84–101. http://dx.doi.org/10.1016/s0039-6028(99)00341-6.

Full text

APA, Harvard, Vancouver, ISO, and other styles

19

Taatjes, Craig A. "How does the molecular velocity distribution affect kinetics measurements by time-resolved mass spectrometry?" International Journal of Chemical Kinetics 39, no. 10 (2007): 565–70. http://dx.doi.org/10.1002/kin.20262.

Full text

APA, Harvard, Vancouver, ISO, and other styles

20

Winter, B., S. J. King, M. Brouard, and C. Vallance. "A fast microchannel plate-scintillator detector for velocity map imaging and imaging mass spectrometry." Review of Scientific Instruments 85, no. 2 (2014): 023306. http://dx.doi.org/10.1063/1.4866647.

Full text

APA, Harvard, Vancouver, ISO, and other styles

21

Skog, Göran, Ragnar Hellborg, and Bengt Erlandsson. "Accelerator Mass Spectrometry at the Lund Pelletron Accelerator." Radiocarbon 34, no. 3 (1992): 468–72. http://dx.doi.org/10.1017/s0033822200063700.

Full text

Abstract:

Three years ago, funds were raised to equip the 3 MV Pelletron accelerator at the Department of Physics, Lund University for accelerator mass spectroscopy (AMS). We have modified the accelerator for mass spectroscopy by relocating focusing devices on both the low- and high-energy side of the accelerator and installing a Wien velocity filter and detectors for measuring the particle energy (E) and energy loss (ΔE). We have been working exclusively with 14C during the initial period. About 40 samples of elemental carbon have been produced, using Fe or Co as catalyst, during the last two years. The 12C− current from these samples is about 3–5 μA using an ANIS sputtering source. We are now planning 14C analyses in the fields of archaeology, Quaternary geology and radioecology.

APA, Harvard, Vancouver, ISO, and other styles

22

Kahen, Kaveh, Kaveh Jorabchi, Callum Gray, and Akbar Montaser. "Spatial Mapping of Droplet Velocity and Size for Direct and Indirect Nebulization in Plasma Spectrometry." Analytical Chemistry 76, no. 24 (2004): 7194–201. http://dx.doi.org/10.1021/ac048954l.

Full text

APA, Harvard, Vancouver, ISO, and other styles

23

Salewski, M., M. Nocente, A. S. Jacobsen, et al. "MeV-range velocity-space tomography from gamma-ray and neutron emission spectrometry measurements at JET." Nuclear Fusion 57, no. 5 (2017): 056001. http://dx.doi.org/10.1088/1741-4326/aa60e9.

Full text

APA, Harvard, Vancouver, ISO, and other styles

24

Cai, Yi-Hong, Yin-Hung Lai, and Yi-Sheng Wang. "Coupled Space- and Velocity-Focusing in Time-of-Flight Mass Spectrometry—a Comprehensive Theoretical Investigation." Journal of The American Society for Mass Spectrometry 26, no. 10 (2015): 1722–31. http://dx.doi.org/10.1007/s13361-015-1206-y.

Full text

APA, Harvard, Vancouver, ISO, and other styles

25

Manning, Christopher J., and Peter R. Griffiths. "Noise Sources in Step-Scan FT-IR Spectrometry." Applied Spectroscopy 51, no. 8 (1997): 1092–101. http://dx.doi.org/10.1366/0003702971941755.

Full text

Abstract:

Step-scan Fourier transform infrared (FT-IR) spectrometry has been accepted as a useful tool for obtaining vibrational spectra of a variety of time-dependent systems. Unfortunately, a significant signal-to-noise ratio (SNR) disadvantage has been associated with the step-scan mode of data collection relative to the same data collection time with conventional rapid-scan FT-IR spectrometry. The key difference between the two methods is the average mirror velocity, which alters the dynamic range of the detector signal, as well as the frequencies of its components. The SNR disadvantage is shown to be related to low-frequency multiplicative fluctuations, caused in part by temperature variations, which convolve noise with measured spectra. Refractive index variations of air or purge gas in the paths of the infrared- and reference-laser radiation can be a particularly serious temperature-induced problem. The various noise sources are described, and experiments confirming that some are related to temperature variations are reported.

APA, Harvard, Vancouver, ISO, and other styles

26

Merrill, Wyatt G., F. Fleming Crim, and Amanda S. Case. "Dynamics and yields for CHBrCl2photodissociation from 215–265 nm." Physical Chemistry Chemical Physics 18, no. 48 (2016): 32999–3008. http://dx.doi.org/10.1039/c6cp05061a.

Full text

Abstract:

We characterize the energy partitioning and spin–orbit yields for CHBrCl₂photodissociation. Resonance enhanced multiphoton ionization selectively detects the Br and Br* product channels. Time of flight mass spectrometry and velocity-map imaging permit measurement of relative quantum yields, as well as kinetic and internal energy distributions. We further interpret the energy partitioning through use of impulsive models.

APA, Harvard, Vancouver, ISO, and other styles

27

Yano, H., M. Nakahara, and H. Ito. "Water Blooms of Uroglena Americana and the Identification of Odorous Compounds." Water Science and Technology 20, no. 8-9 (1988): 75–80. http://dx.doi.org/10.2166/wst.1988.0227.

Full text

Abstract:

Since July 1980, a strong fishy odor in the Nunobiki Reservoir has been associated with water blooms of the alga Uroglenaamericana (Chrysophyceae). According to ecological studies, water blooms were formed hourly by vertical and horizontal accumulation. The movement of organisms was affected by weather conditions, including the amount of sunlight and the direction and velocity of the wind. To identify the odorous compounds, samples of this species were collected from water blooms by a plankton net. The odorous compounds were analyzed by gas chromatography mass spectrometry (GC-MS), nuclear magnetic resonance (NMR), and ultra-violet (UV) spectrometry. As a result, two odorous compounds, (E,E)-2,4-heptadienal and (E,Z)-2,4-heptadienal, were detected and identified.

APA, Harvard, Vancouver, ISO, and other styles

28

Teramoto, T., J. Adachi, M. Yamazaki, et al. "Extensive study on the C 1s photoionization of CS2molecules by multi-coincidence velocity-map imaging spectrometry." Journal of Physics B: Atomic, Molecular and Optical Physics 40, no. 20 (2007): 4033–46. http://dx.doi.org/10.1088/0953-4075/40/20/006.

Full text

APA, Harvard, Vancouver, ISO, and other styles

29

van der Heide, P. A. W. "Comment on “The ‘infinite velocity method’: a means of concentration calibration in secondary ion mass spectrometry?”." Surface Science 453, no. 1-3 (2000): L328—L331. http://dx.doi.org/10.1016/s0039-6028(00)00364-2.

Full text

APA, Harvard, Vancouver, ISO, and other styles

30

Svrčková, Pavla, Andriy Pysanenko, Jozef Lengyel, et al. "Photodissociation dynamics of ethanethiol in clusters: complementary information from velocity map imaging, mass spectrometry and calculations." Physical Chemistry Chemical Physics 17, no. 39 (2015): 25734–41. http://dx.doi.org/10.1039/c5cp00367a.

Full text

APA, Harvard, Vancouver, ISO, and other styles

31

Hadarcev, Aleksandr, G. Suhih, V. Platonov, et al. "CHROMATOGRAPHY AND MASS SPECTROMETRY OF CHLOROFORM EXTRACT OF YARROW (ACHILLED MILLEFOLIUM L. COMMON DANDELION) (message III)." Clinical Medicine and Pharmacology 6, no. 3 (2020): 41–46. http://dx.doi.org/10.12737/2409-3750-2020-6-3-41-46.

Full text

Abstract:

The purpose of the study is to detail the information about the peculiarities of the chemical composition and structural organization of different groups of compounds of organic matter, yarrow, revealing the influence of nature of the extractant on the qualitative composition and quantitative content of extractable compounds in the obtained chloroform extract, and identifying new pharmacological actions of the latter, the extension of the range of compounds already known in the literature on herbal medicine. Materials and methods of research. The chemical composition of the chloroform extract was studied by chromatography-mass spectrometry under the following conditions. The chemical composition of the ethanol extract of yarrow was used by chromatography-mass spectrometry under the following conditions. GC-2010 gas chromatograph connected to a triple quadrupole mass spectrometer GCMS-TQ-8030 running GCMS Solution 4.11 software. Identification and quantitative determination of the content of compounds were performed under the following chromatography conditions: sample input with flow division (1:10), ZB-5MS column (30m × 0.25 mm × 0.25 mm), injector temperature 280 °C, carrier gas-helium, gas velocity through the column 29 ml/min. Conclusion. For the first time, the chemical composition of chloroform extract, a product of sequential exhaustive extraction of yarrow by chromatography — mass spectrometry, was studied, which allows identifying 94 individual compounds for which mass spectra and structural formulas were obtained, the quantitative content was determined, and the structural and group composition of the extract was calculated. The basis of the composition of the chloroform extract is determined by hydrocarbons enriched with arenes, alkenes and alkynes, esters formed mainly by oxalic and benzoic acids, polyunsaturated fatty carboxylic acids, steroid compounds, alcohols, nitrogen-containing structures that include individual fragments of natural alkaloids, as well as a variety of organosilicon compounds that determine the main directions of pharmacological action of various yarrow preparations, including chloroform extract.

APA, Harvard, Vancouver, ISO, and other styles

32

Meyer, Stefan, Marek Tulej, and Peter Wurz. "Mass spectrometry of planetary exospheres at high relative velocity: direct comparison of open- and closed-source measurements." Geoscientific Instrumentation, Methods and Data Systems 6, no. 1 (2017): 1–8. http://dx.doi.org/10.5194/gi-6-1-2017.

Full text

Abstract:

Abstract. The exploration of habitable environments on or inside icy moons around the gas giants in the solar system is of major interest in upcoming planetary missions. Exactly this theme is addressed by the JUpiter ICy moons Explorer (JUICE) mission of ESA, which will characterise Ganymede, Europa and Callisto as planetary objects and potential habitats. We developed a prototype of the Neutral Gas and Ion Mass spectrometer (NIM) of the Particle Environment Package (PEP) for the JUICE mission intended for composition measurements of neutral gas and thermal plasma. NIM/PEP will be used to measure the chemical composition of the exospheres of the icy Jovian moons. Besides direct ion measurement, the NIM instrument is able to measure the inflowing neutral gas in two different modes: in neutral mode, where the gas enters directly the ion source (open source), and in thermal mode, where the gas gets thermally accommodated to the wall temperature by several collisions inside an equilibrium sphere, called antechamber, before entering the ion source (closed source). We performed measurements with the prototype NIM using a neutral gas beam of 1 up to 4.5 km s−1 velocity in the neutral and thermal mode. The current trajectory of JUICE foresees a flyby velocity of 4 km s−1 at Europa; other flybys are in the range of 1 up to 7 km s−1 and orbital velocity in Ganymede orbits is around 2 km s−1. Different species are used for the gas beam, such as noble gases Ne, Ar, Kr as well as molecules like H2, methane, ethane, propane and more complex ones. The NIM prototype was successfully tested under realistic JUICE mission conditions. In addition, we find that the antechamber (closed source) behaves as expected with predictable density enhancement over the specified mass range and within the JUICE mission phase velocities. Furthermore, with the open source and the closed source we measure almost the same composition for noble gases, as well as for molecules, indicating no additional fragmentation of the species recorded with the antechamber for the investigated parameter range.

APA, Harvard, Vancouver, ISO, and other styles

33

Vaida, Mihai E., and Thorsten M. Bernhardt. "Surface pump-probe femtosecond-laser mass spectrometry: Time-, mass-, and velocity-resolved detection of surface reaction dynamics." Review of Scientific Instruments 81, no. 10 (2010): 104103. http://dx.doi.org/10.1063/1.3488098.

Full text

APA, Harvard, Vancouver, ISO, and other styles

34

Bull, James N., Jason W. L. Lee, and Claire Vallance. "Quantification of ions with identical mass-to-charge (m/z) ratios by velocity-map imaging mass spectrometry." Physical Chemistry Chemical Physics 15, no. 33 (2013): 13796. http://dx.doi.org/10.1039/c3cp52219a.

Full text

APA, Harvard, Vancouver, ISO, and other styles

35

Wood, Kenneth. "Spectropolarimetric determination of circumstellar disc inclinations." Symposium - International Astronomical Union 162 (1994): 230–31. http://dx.doi.org/10.1017/s0074180900214915.

Full text

Abstract:

Inference of the density and velocity structure of rotating/expanding circumstellar discs/winds is of considerable interest in the understanding of stellar mass loss. High resolution line spectropolarimetry creates the possibility of diagnosing such envelope structure much more fully than broad band polarimetry or high resolution spectrometry alone since each element of the scattered spectropolarimetric profile picks out the element of the envelope with the appropriate Doppler shift and provides orientation information on it. This problem has been formulated in detail by Wood, et al (1993) for scattering of a finite width line in a flattened envelope – the spectral shape of the scattered Stokes fluxes being determined by isowavelength–shift contours or surfaces which give the relative wavelength shift of the scattered radiation at different regions in the disc. It was also shown how, in the case of a narrow stellar line scattered in a rotating or expanding flat disc with a simply parametrised density and velocity structure (ignoring the smearing effect of electron thermal motions), it is possible to infer the system inclination and structure model parameters from the resulting spectropolarimetric line profile. This poster presents a method for determining the disc inclination from analysis of the scattered profiles – a parameter which cannot be determined uniquely from spectrometry alone – and thus illustrates the powerful diagnostic potential of high resolution line spectropolarimetry.

APA, Harvard, Vancouver, ISO, and other styles

36

Wang, Xing Guo. "The Chrome Thin Coating Characteristics Using Ultrasonic Testing." Applied Mechanics and Materials 253-255 (December 2012): 299–302. http://dx.doi.org/10.4028/www.scientific.net/amm.253-255.299.

Full text

Abstract:

According to the different thickness of the thin coatings, the echo signal of ultrasonic testing was extracted. The sound velocity in the coating medium was obtained by solving the mathematical model for transfer function and the time delay spectrometry method, and the coating thickness was calculated, the comparison error of the calculated thickness and the actual thickness, combined with the actual thickness of the coating. The results showed that, two kinds of testing methods are able to detect thin coating thickness.

APA, Harvard, Vancouver, ISO, and other styles

37

Bard, Edouard, Maurice Arnold, Pierre Maurice, Josette Duprat, Jean Moyes, and Jean-Claude Duplessy. "Retreat velocity of the North Atlantic polar front during the last deglaciation determined by 14C accelerator mass spectrometry." Nature 328, no. 6133 (1987): 791–94. http://dx.doi.org/10.1038/328791a0.

Full text

APA, Harvard, Vancouver, ISO, and other styles

38

Shum, Sam C. K., Steve K. Johnson, Ho-Ming Pang, and R. S. Houk. "Spatially Resolved Measurements of Size and Velocity Distributions of Aerosol Droplets from a Direct Injection Nebulizer." Applied Spectroscopy 47, no. 5 (1993): 575–83. http://dx.doi.org/10.1366/0003702934067108.

Full text

Abstract:

Aerosol droplet sizes and velocities from a direct injection nebulizer (DIN) are measured with radial and axial spatial resolution by phase Doppler particle analysis (PDPA). The droplets on the central axis of the spray become finer and their size becomes more uniform when ≍ 20% methanol is added to the usual aqueous solvent. This could explain why the analyte signal is a maximum at this solvent composition when the DIN is used for inductively coupled plasma-mass spectrometry (ICP-MS). Mean droplet velocities are 12 to 22 ms−1 with standard deviations of ±4 to ±7 ms−1. The outer fringes of the aerosol plume tend to be enriched in large droplets. The Sauter mean diameter ( D3,2) and velocity of the droplets also vary substantially with axial position in the aerosol plume.

APA, Harvard, Vancouver, ISO, and other styles

39

Akbarzadeh, Omid, Solhe F. Alshahateet, Noor Asmawati Mohd Zabidi, et al. "Effect of Temperature, Syngas Space Velocity and Catalyst Stability of Co-Mn/CNT Bimetallic Catalyst on Fischer Tropsch Synthesis Performance." Catalysts 11, no. 7 (2021): 846. http://dx.doi.org/10.3390/catal11070846.

Full text

Abstract:

The effect of reaction temperature, syngas space velocity, and catalyst stability on Fischer-Tropsch reaction was investigated using a fixed-bed microreactor. Cobalt and Manganese bimetallic catalysts on carbon nanotubes (CNT) support (Co-Mn/CNT) were synthesized via the strong electrostatic adsorption (SEA) method. For testing the performance of the catalyst, Co-Mn/CNT catalysts with four different manganese percentages (0, 5, 10, 15, and 20%) were synthesized. Synthesized catalysts were then analyzed by TEM, FESEM, atomic absorption spectrometry (AAS), and zeta potential sizer. In this study, the temperature was varied from 200 to 280 °C and syngas space velocity was varied from 0.5 to 4.5 L/g.h. Results showed an increasing reaction temperature from 200 °C to 280 °C with reaction pressure of 20 atm, the Space velocity of 2.5 L/h.g and H2/CO ratio of 2, lead to the rise of CO % conversion from 59.5% to 88.2% and an increase for C5+ selectivity from 83.2% to 85.8%. When compared to the other catalyst formulation, the catalyst sample with 95% cobalt and 5% manganese on CNT support (95Co5Mn/CNT) performed more stable for 48 h on stream.

APA, Harvard, Vancouver, ISO, and other styles

40

HIGASHI, Yasuhiro, and Yoshikazu HOMMA. "Quantification Method Using the Inverse Velocity Dependence of Ion Intensities in Secondary Ion Mass Spectrometry: the High-Energy Method." Analytical Sciences 14, no. 2 (1998): 281–86. http://dx.doi.org/10.2116/analsci.14.281.

Full text

APA, Harvard, Vancouver, ISO, and other styles

41

Wittmaack, K. "Reply to the ‘Comment on “The ‘infinite velocity method’: a means of concentration calibration in secondary ion mass spectrometry?”’." Surface Science 453, no. 1-3 (2000): L332—L335. http://dx.doi.org/10.1016/s0039-6028(00)00365-4.

Full text

APA, Harvard, Vancouver, ISO, and other styles

42

Chagovets, Vitaliy, Vladimir Frankevich, and Renato Zenobi. "Initial Velocity Distribution of MALDI/LDI Ions Measured by Internal MALDI Source Fourier-Transform Ion Cyclotron Resonance Mass Spectrometry." Journal of The American Society for Mass Spectrometry 25, no. 11 (2014): 1991–94. http://dx.doi.org/10.1007/s13361-014-0971-3.

Full text

APA, Harvard, Vancouver, ISO, and other styles

43

Yang, Husheng, Peter R. Griffiths, and Christopher J. Manning. "Improved Data Processing by Application of Brault's Method to Ultra-Rapid-Scan FT-IR Spectrometry." Applied Spectroscopy 56, no. 10 (2002): 1281–88. http://dx.doi.org/10.1366/000370202760354984.

Full text

Abstract:

In Fourier transform infrared spectrometry, the use of analog-to-digital converters clocked at a constant rate leads to interferograms the data points of which are evenly spaced in time. An interpolation step is generally required to resample these data to equal intervals of retardation. Three methods of resampling the data were compared: Fourier interpolation (i.e., zero-filling), cubic interpolation, and digital filter interpolation as described by Brault. These approaches were investigated using both simulated data and interferograms acquired from an ultra-rapid scanning Fourier transform infrared spectrometer. In both cases, the optical path difference varied sinusoidally with time and interferograms were sampled at equal time intervals. It was shown that the data processing time can be reduced significantly, relative to previous methods, through the application of Brault's method, which can be considered as three separate steps involving a first-, second-, and third-order correction. If only the first-order correction for the local phase relationship between the sampling grids is applied, the noise level of resulting spectra is similar to that obtained by cubic fitting, but the data processing time is reduced significantly. If the second-order correction for the variation of velocity is also used, the data processing time is approximately the same as the first-order correction, while the signal-to-noise ratio of the spectra is increased significantly. The implementation of the third-order correction for channel delay mismatch appears to be unnecessary for this instrument because the detector channel delays are small.

APA, Harvard, Vancouver, ISO, and other styles

44

Farmer, D. K., J. R. Kimmel, G. Phillips, et al. "Eddy covariance measurements with high-resolution time-of-flight aerosol mass spectrometry: a new approach to chemically-resolved aerosol fluxes." Atmospheric Measurement Techniques Discussions 3, no. 6 (2010): 5867–905. http://dx.doi.org/10.5194/amtd-3-5867-2010.

Full text

Abstract:

Abstract. Although laboratory studies show that biogenic volatile organic compounds (VOCs) yield substantial secondary organic aerosol (SOA), production of biogenic SOA as indicated by upward fluxes has not been conclusively observed over forests. Further, while aerosols are known to deposit to surfaces, few techniques exist to provide chemically-resolved particle deposition fluxes. To better constrain aerosol sources and sinks, we have developed a new technique to directly measure fluxes of chemically-resolved submicron aerosols using the high-resolution time-of-flight aerosol mass spectrometer (HR-AMS) in a new, fast eddy covariance mode. This approach takes advantage of the instrument's ability to quantitatively identify both organic and inorganic components, including ammonium, sulphate and nitrate, at a temporal resolution of several Hz. The new approach has been successfully deployed over a temperate ponderosa pine plantation in California during the BEARPEX-2007 campaign, providing both total and chemically resolved non-refractory (NR) PM1 fluxes. Average deposition velocity for total NR-PM1 aerosol at noon was 2.05 ± 0.04 mm/s. Using a high resolution measurement of the NH2+ and NH3+ fragments, we demonstrate the first eddy covariance flux measurements of particulate ammonium, which show a noon-time deposition velocity of 1.9 ± 0.7 mm/s and are dominated by deposition of ammonium sulphate.

APA, Harvard, Vancouver, ISO, and other styles

45

Asakawa, Daiki, Motoshi Sakakura, and Mitsuo Takayama. "Influence of initial velocity of analytes on in-source decay products in MALDI mass spectrometry using salicylic acid derivative matrices." International Journal of Mass Spectrometry 337 (March 2013): 29–33. http://dx.doi.org/10.1016/j.ijms.2012.12.008.

Full text

APA, Harvard, Vancouver, ISO, and other styles

46

Hearnshaw, J. B. "Cassegrain echelle spectroscopy with small telescopes." Symposium - International Astronomical Union 118 (1986): 371–84. http://dx.doi.org/10.1017/s0074180900151769.

Full text

Abstract:

This paper comments on the growing use of cassegrain échelle spectrographs for high resolving power astronomical spectroscopy over the last two decades. Some of the theoretical and practical advantages of échelle spectrographs are outlined, as well as some of the problems that arise in their use. Design parameters of some recent échelle spectrographs in various observatories are summarised. A novel use of échelle spectrographs without a cross-dispersing element for radial velocity spectrometry is proposed. The design parameters of a fibre-fed échelle spectrograph that will achieve a resolving power of about 7 × 104 with a 2 arc second input from a 1m telescope are outlined.

APA, Harvard, Vancouver, ISO, and other styles

47

Silva, Bruno Guzzo, Ana Maria Frattini Fileti, Mary Ann Foglio, Paulo de Tarso Vieira Rosa, and Osvaldir Pereira Taranto. "Effects of Different Drying Conditions on Key Quality Parameters of Pink Peppercorns (Schinus terebinthifolius Raddi)." Journal of Food Quality 2017 (2017): 1–12. http://dx.doi.org/10.1155/2017/3152797.

Full text

Abstract:

Pink peppercorns are among the most sophisticated condiments in the international cuisine. This culinary spice is obtained from dried fruits of Schinus terebinthifolius Raddi, a species native to South America. In this work, a methodology for the assessment of pink peppercorn quality under various drying conditions was defined. Experiments were performed in a pilot tray dryer, which ensured integrity of the product. A central composite rotatable design with 11 experiments was devised to study the influence of drying air temperature (35–75°C) and air velocity (0.3–0.9 m/s) on product quality, assessed by moisture content, color (CIELAB system), and volatile compounds. The essential oils of fresh and dried fruits were extracted by hydrodistillation and analyzed by gas chromatography coupled to mass spectrometry. Air temperature had the greatest influence on the quality parameters under study, while air velocity had no statistically significant effect. Considering all quality criteria, temperatures between 40 and 55°C provided the best compromise, yielding an adequate moisture content in the dried product without dramatic degradation of color and essential oil.

APA, Harvard, Vancouver, ISO, and other styles

48

Zhang, Yimin, Yan Wang, Ligang Zheng, Tao Yang, Jianliang Gao, and Zhenhua Li. "Effect of Pristine Palygorskite Powders on Explosion Characteristics of Methane-Air Premixed Gas." Energies 11, no. 10 (2018): 2496. http://dx.doi.org/10.3390/en11102496.

Full text

Abstract:

In this study, pristine palygorskite powders were used as the inhibition materials to suppress the explosion of methane-air premixed gas for the first time. The composition, porosity and pyrolysis characteristics of the powders were tested by X-ray diffraction (XRD), energy dispersive spectrometry (EDS), N2 adsorption-desorption and Thermogravimetry-differential scanning calorimetry (TG-DSC) techniques. The effects of pristine palygorskite powders concentration on the explosion pressure and the average velocity of flame propagation of the 9.5% methane-air premixed gas were tested by a 20 L spherical explosion system and a 5 L pipeline explosion system. The results indicated the pristine palygorskite powders possess a considerable suppression property on methane explosion. When the mass concentration of pristine palygorskite powders was 0.20 g·L−1, the max-pressure of methane explosion was decreased by 23.9%. The methane explosion flame propagation velocity was inhibited obviously. Owing to the excellent inhibitory performance and the advantage of low-cost and environmental harmlessness, pristine palygorskite powders are potential new materials for the application on gas explosion suppression.

APA, Harvard, Vancouver, ISO, and other styles

49

Li, Chen, Noel W. Solomons, Marilyn E. Scott, and Kristine G. Koski. "Anthropometry before Day 46 and Growth Velocity before 6 Months of Guatemalan Breastfed Infants Are Associated with Subclinical Mastitis and Milk Cytokines, Minerals, and Trace Elements." Journal of Nutrition 149, no. 9 (2019): 1651–59. http://dx.doi.org/10.1093/jn/nxz109.

Full text

Abstract:

ABSTRACT Background Subclinical mastitis (SCM) is an inflammatory condition of the mammary gland, but its association with human milk composition and infant growth is not well described. Objectives We investigated whether SCM, milk cytokines, and/or estimated intakes of milk minerals and trace elements were associated with infant anthropometry or growth velocity before 6 mo. Methods Breast milk was collected from Mam-Mayan mothers (n = 114) at both early (2–46 d) and established (4–6 mo) lactation. Concentrations of 9 elements (sodium, potassium, calcium, magnesium, copper, iron, manganese, selenium, zinc) analyzed by inductively-coupled plasma mass spectrometry were used to estimate infants’ daily intakes. Concentrations of 4 cytokines were measured. Milk concentrations and infants' estimated elemental intakes and anthropometric measurements during early and established lactation were compared by SCM status. Multiple regression was used to identify factors associated with infant growth attainment (<46 d) for infant weight- (WAZ), length- (LAZ), and head circumference-for-age (HCAZ) and weight-for-length (WLZ) z scores and with growth velocity (expressed as Δ/d) from early to established lactation. Results SCM prevalence was higher in early (30%) than established (10%) lactation. Breast milk of SCM mothers had higher cytokine concentrations and higher magnesium in early and higher selenium concentrations in both early and established lactation (Padj < 0.0121). At day 46, regression models showed inverse associations of SCM with WLZ and IL-1β with LAZ (Padj < 0.0150). In contrast, linear growth velocity was positively associated with IL-1β measured in early lactation (Padj < 0.0124), whereas cranial growth velocity was positively associated with IL-8 measured during established lactation ( Padj < 0.0124). Conclusions Despite a high prevalence of inadequate intakes, only infants’ intake of milk magnesium during early lactation was associated with linear growth velocity in breastfed infants <6 mo. Evidence shows that SCM, breast-milk cytokines, and infants' estimated intakes of select elements are independently associated with growth attainment and growth velocity during lactation.

APA, Harvard, Vancouver, ISO, and other styles

50

LILL, TH, H. G. BUSMANN, F. LACHER, and I. V. HERTEL. "${\rm C}^+_{60}$ IONS IN COLLISIONS WITH CRYSTALLINE SURFACES: KINEMATICS AND DYNAMICS." International Journal of Modern Physics B 10, no. 01 (1996): 11–57. http://dx.doi.org/10.1142/s0217979296000039.

Full text

Abstract:

Collisions of [Formula: see text] ions with surfaces of highly oriented pyrolytic graphite (HOPG), diamond (111) and heteroepitaxial fullerite films on mica in the impact energy range between 100 and 1500 eV are studied by mass, energy, and angle resolved time-of-flight mass spectrometry. For the graphite and diamond surfaces, highly inelastic scattering has been observed. The analysis of the velocity dependence of the scattered ions reveals that the normal and tangential component of the ion velocity have different significance for the collision dynamics. The normal component of the velocity appears to determine the amount of energy transferred into vibrational and deformational energy of the projectile and target. The final kinetic energy is independent of the impact energy for impact angles of ≈20° and impact energies between 140 and 450 eV. This observation can be explained by the existence of an upper bound of the final kinetic energy that is defined by the amount of energy stored in the deformed molecule without being deposited or destroyed. The tangential component is partially transformed into rotational energy of the [Formula: see text] in the collision with the surface, as may be explained by a simple rolling ball model. In contrast, scattering from heteroepitaxial fullerite films is nearly elastic for impact energies up to 230 eV and impact angles of about 20°. Additionally, the velocity distributions reveal a low velocity component. Its relative intensity increases with increasing impact energy and remains the only feature in the velocity distribution for impact energies higher than 290 eV. This component is due to sputtering of surface molecules. The angular dependent intensities of the fast ions exhibit a rich structure. This can be attributed to rainbow scattering, as confirmed by classical trajectory and molecular dynamics calculations with different levels of sophistication. These calculations also show that linear collision sequences along the closed packed rows of the fullerite surface may be generated as the result of the [Formula: see text] impact. A detailed study of these collision sequences by molecular dynamics calculations reveals that rainbow effects might be possible when these sequences are defocused due to thermal motion of the surface molecules. The contribution of this process to the measured velocity and angular distributions is discussed.

APA, Harvard, Vancouver, ISO, and other styles

We offer discounts on all premium plans for authors whose works are included in thematic literature selections. Contact us to get a unique promo code!