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1
Полетаев, С. Д., та А. И. Любимов. "Особенности согласования нижнего электрода с высокочастотным генератором смещения при реактивно-ионном травлении массивных подложек". Журнал технической физики 91, № 4 (2021): 657. http://dx.doi.org/10.21883/jtf.2021.04.50630.271-20.
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This paper presents theoretical and experimental results on reactive ion etching of massive substrates in freon-14 with RF bias at the lower electrode. A hypothesis is proposed according to which a large-sized substrate violates the matching of the lower electrode with the RF generator by adding an additional reactive component to the impedance of the lower electrode. A numerical simulation of reactive ion etching with substrates of various sizes in a CF4 environment is performed . The simulation results showed a significant increase in the reactive component of RF power at the lower electrode if the substrate area exceeds 50% of the area of the lower electrode, which is consistent with the proposed hypothesis. It has been experimentally shown that the etching of massive substrates violates the matching of the lower electrode with the RF generator. A special design of the substrate holder for massive substrates has been developed. It is shown that such a substrate holder significantly improves the matching of the RF generator with the lower electrode, especially when adding 0.3-0.9 l/h argon to the plasma-forming mixture.
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Suraya, A. N., T. Sabapathy, M. Jusoh, et al. "Wearable antenna gain enhancement using reactive impedance substrate." Indonesian Journal of Electrical Engineering and Computer Science 13, no. 2 (2019): 708–12. https://doi.org/10.11591/ijeecs.v13.i2.pp708-712.
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A microstrip patch antenna is designed for a wearable antenna. The performance of microstrip patch antenna loaded with reactive impedance surface (RIS) is described in terms of gain, bandwidth and return loss. The antenna is investigated in two conditions which are conventional microstrip antenna with RIS and without RIS. The designed antenna is also aimed at size reduction therefore it will be suitable for a wearable application. This antenna which is made fully using textile and it is designed for operation in the 2.45 GHz band. The performance of microstrip patch antenna loaded with RIS is described in terms of gain, bandwidth, return loss and radiation pattern. The antenna designed with RIS operates at 2.45 GHz. Bandwidth enhancement is achieved with RIS where the designed antenna can cater frequency from 2.4 GHz to 3 GHz. A gain enhancement is achieved of 20% is achieved compared with the conventional patch antenna. Although the size of the patch is reduced with the introduction of RIS, the overall size of the antenna with the substrate is almost similar to the conventional patch antenna. However, the performance of the antenna is greatly enhanced with the use of RIS.
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Suraya, A. N., T. Sabapathy, M. Jusoh, et al. "Wearable antenna gain enhancement using reactive impedance substrate." Indonesian Journal of Electrical Engineering and Computer Science 13, no. 2 (2019): 708. http://dx.doi.org/10.11591/ijeecs.v13.i2.pp708-712.
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A microstrip patch antenna is designed for a wearable antenna. The performance of microstrip patch antenna loaded with reactive impedance surface (RIS) is described in terms of gain, bandwidth and return loss. The antenna is investigated in two conditions which are conventional microstrip antenna with RIS and without RIS. The designed antenna is also aimed at size reduction therefore it will be suitable for a wearable application. This antenna which is made fully using textile and it is designed for operation in the 2.45 GHz band. The performance of microstrip patch antenna loaded with RIS is described in terms of gain, bandwidth, return loss and radiation pattern. The antenna designed with RIS operates at 2.45 GHz. Bandwidth enhancement is achieved with RIS where the designed antenna can cater frequency from 2.4 GHz to 3 GHz. A gain enhancement is achieved of 20% is achieved compared with the conventional patch antenna. Although the size of the patch is reduced with the introduction of RIS, the overall size of the antenna with the substrate is almost similar to the conventional patch antenna. However, the performance of the antenna is greatly enhanced with the use of RIS.
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Mosallaei, H., and K. Sarabandi. "Antenna Miniaturization and Bandwidth Enhancement Using a Reactive Impedance Substrate." IEEE Transactions on Antennas and Propagation 52, no. 9 (2004): 2403–14. http://dx.doi.org/10.1109/tap.2004.834135.
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Sarabandi, K., A. M. Buerkle, and H. Mosallaei. "Compact Wideband UHF Patch Antenna on a Reactive Impedance Substrate." IEEE Antennas and Wireless Propagation Letters 5, no. 1 (2006): 503–6. http://dx.doi.org/10.1109/lawp.2006.886302.
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Samanta, Gopinath, Debasis Mitra, and Sekhar Ranjan Bhadra Chaudhuri. "Miniaturization of a patch antenna using circular reactive impedance substrate." International Journal of RF and Microwave Computer-Aided Engineering 27, no. 8 (2017): e21126. http://dx.doi.org/10.1002/mmce.21126.
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Roestorff, Martin, Johann W. Odendaal, and Johan Joubert. "Antenna with a reactive impedance substrate for mine rescue applications." Microwave and Optical Technology Letters 61, no. 1 (2018): 44–50. http://dx.doi.org/10.1002/mop.31541.
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Dmitriev, V. M., E. L. Kravchenko, M. N. Ofitserov, N. N. Prentslau, V. N. Svetlov, and V. B. Stepanov. "Temperature correlation of peculiarities of the impedance of a YBa2Cu3Ox film and an SrTiO3 substrate." Low Temperature Physics 19, no. 4 (1993): 318–20. https://doi.org/10.1063/10.0033410.
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Temperature correlation has been established between the anomalies of ohmic losses and the reactive response of a SrTiO3 substrate and a YBa2Cu3Ox film. Impedance peculiarities that are characteristic for the substrate and material of the film separately are not observed in bulk samples of YBa2Cu3Ox and in metallic films deposited on a SrTiO3 substrate.
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Kumar, Saurabh, and Dinesh Kumar Vishwakarma. "Miniaturized bent slotted patch antenna over a reactive impedance surface substrate." International Journal of Microwave and Wireless Technologies 8, no. 2 (2015): 347–52. http://dx.doi.org/10.1017/s1759078715000057.
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A reactive impedance surface (RIS) based miniaturized bent slotted patch antenna is proposed and investigated for S-band applications around 2.39 GHz. Bent slots in the patch reduce the patch antenna size by increasing current path on the patch. Further a RIS substrate with cross-shaped patch elements printed over a grounded dielectric is optimized and investigated for antenna miniaturization. The proposed bent slotted patch antenna over RIS substrate is 38.75% miniaturized with respect to traditional patch antenna at a fixed operating frequency. The proposed antenna reveals an overall volume of 0.280λ0 × 0.280λ0 × 0.036λ0on a low-cost FR4 substrate at 2.39 GHz for S-band applications. The proposed antenna is fabricated and measured for its return loss. The measured results are in good agreement with simulated one.
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Samanta, Gopinath, and Debasis Mitra. "Dual-Band Circular Polarized Flexible Implantable Antenna Using Reactive Impedance Substrate." IEEE Transactions on Antennas and Propagation 67, no. 6 (2019): 4218–23. http://dx.doi.org/10.1109/tap.2019.2905978.
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Samanta, G., and D. Mitra. "Wideband THz antenna using graphene based tunable circular reactive impedance substrate." Optik 158 (April 2018): 1080–87. http://dx.doi.org/10.1016/j.ijleo.2017.12.197.
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Kumar, Saurabh, and Dinesh Kumar Vishwakarma. "Miniaturized bent slotted patch antenna over a reactive impedance surface substrate – ERRATUM." International Journal of Microwave and Wireless Technologies 8, no. 2 (2015): 395. http://dx.doi.org/10.1017/s1759078715000501.
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Zhang, Huan, Yong-Chang Jiao, Gang Zhao, and Rui-Qi Wang. "Compact circularly polarized conical-beam antenna based on the reactive impedance substrate." Microwave and Optical Technology Letters 59, no. 2 (2016): 240–43. http://dx.doi.org/10.1002/mop.30267.
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Anam, Mohamad Khoirul, and Sangjo Choi. "Perfect Absorption Efficiency Circular Nanodisk Array Integrated with a Reactive Impedance Surface with High Field Enhancement." Nanomaterials 10, no. 2 (2020): 258. http://dx.doi.org/10.3390/nano10020258.
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Infrared (IR) absorbers based on a metal–insulator–metal (MIM) have been widely investigated due to their high absorption performance and simple structure. However, MIM absorbers based on ultrathin spacers suffer from low field enhancement. In this study, we propose a new MIM absorber structure to overcome this drawback. The proposed absorber utilizes a reactive impedance surface (RIS) to boost field enhancement without an ultrathin spacer and maintains near-perfect absorption by impedance matching with the vacuum. The RIS is a metallic patch array on a grounded dielectric substrate that can change its surface impedance, unlike conventional metallic reflectors. The final circular nanodisk array mounted on the optimum RIS offers an electric field enhancement factor of 180 with nearly perfect absorption of 98% at 230 THz. The proposed absorber exhibits robust performance even with a change in polarization of the incident wave. The RIS-integrated MIM absorber can be used to enhance the sensitivity of a local surface plasmon resonance (LSPR) sensor and surface-enhanced IR spectroscopy.
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Dr. R. Gayathri, K. Mahendran,. "PERFORMANCE IMPROVED TRIANGULAR MULTI BAND ANTENNA USING REACTIVE IMPEDANCE SUBSTRATE AND FREQUENCY SELECTIVE SURFACE." INFORMATION TECHNOLOGY IN INDUSTRY 9, no. 1 (2021): 486–92. http://dx.doi.org/10.17762/itii.v9i1.159.
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In modern world, communication devices need to be operated for more than one frequency bands. Lot of research works were carried out in the field of multiband antennas. The one major concern in the design of multiband patch antenna are the gain and bandwidth. Both gain and bandwidth of the multi band antenna can be improved for the better performance. In this paper a triangular multiband antenna is designed and the gain of the antenna is enhanced by the blend of reactive impedance surface and Frequency selective surface. The proposed antenna resonates 3.4 GHz, 4.2 GHz, 6.75 GHz,7.1 GHz, 7.5 GHz and 9.3 GHz with a better return loss and gain.
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Agarwal, Kush, Nasimuddin, and A. Alphones. "Compact asymmetric-slotted-slit patch based circularly-polarized antenna with reactive impedance surface substrate." Microwave and Optical Technology Letters 54, no. 11 (2012): 2505–10. http://dx.doi.org/10.1002/mop.27147.
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Reddy, V. V., and N. V. S. N. Sarma. "Reactive impedance surface-based broadband circularly polarized Koch fractal boundary microstrip antenna." International Journal of Microwave and Wireless Technologies 8, no. 2 (2014): 243–50. http://dx.doi.org/10.1017/s1759078714001421.
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A circularly polarized (CP) broadband antenna is proposed for wireless applications in the range of 2–3 GHz frequency. It consists of asymmetrical Koch fractal boundary patch over a reactive impedance surface (RIS) substrate. The simulations of single-layer Koch fractal antenna, dual layer with square and fractal RIS elements are carried out in a systematic way for broadband CP radiation and corresponding results are presented. For better CP characteristics, properties of fractal curves and dimensions of RIS elements are optimized. The antenna with fractal RIS iteration order one (iteration1) is experimentally studied. The 10-dB return loss bandwidth is 50.35%, whereas 3-dB axial ratio bandwidth is 7.45%, which indicate that by applying fractals concept to RIS technique, with a single probe feed, broadband CP radiation can be obtained.
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Macwan, Isaac, Ashish Aphale, Prathamesh Bhagvath, Shalini Prasad, and Prabir Patra. "Detection of Cardiovascular CRP Protein Biomarker Using a Novel Nanofibrous Substrate." Biosensors 10, no. 6 (2020): 72. http://dx.doi.org/10.3390/bios10060072.
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It is known that different diseases have characteristic biomarkers that are secreted very early on, even before the symptoms have developed. Before any kind of therapeutic approach can be used, it is necessary that such biomarkers be detected at a minimum concentration in the bodily fluids. Here, we report the fabrication of an interdigitated sensing device integrated with polyvinyl alcohol (PVA) nanofibers and carbon nanotubes (CNT) for the detection of an inflammatory biomarker, C-reactive protein (CRP). The limit of detection (LOD) was achieved in a range of 100 ng mL−1 and 1 fg mL−1 in both phosphate buffered saline (PBS) and human serum (hs). Furthermore, a significant change in the electrochemical impedance from 45% to 70% (hs) and 38% to 60% (PBS) over the loading range of CRP was achieved. The finite element analysis indicates that a non-redox charge transduction at the solid/liquid interface on the electrode surface is responsible for the enhanced sensitivity. Furthermore, the fabricated biosensor consists of a large electro-active surface area, along with better charge transfer characteristics that enabled improved specific binding with CRP. This was determined both experimentally and from the simulated electrochemical impedance of the PVA nanofiber patterned gold electrode.
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Xie, Chunlin, Zefang Yang, Qi Zhang, et al. "Designing Zinc Deposition Substrate with Fully Preferred Orientation to Elude the Interfacial Inhomogeneous Dendrite Growth." Research 2022 (August 19, 2022): 1–9. http://dx.doi.org/10.34133/2022/9841343.
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The development of zinc-ion batteries with high energy density remains a great challenge due to the uncontrollable dendrite growth on their zinc metal anodes. Film anodes plated on the substrate have attracted increasing attention to alleviate these dendrite issues. Herein, we first point out that both the random crystal orientation and the low metal affinity of the substrate are important factors of zinc dendrite formation. Accordingly, the (1 0 1) fully preferred tin interface layer with high zinc affinity was fabricated by chemical tin plating on (1 0 0) oriented copper. This tin decorated copper substrate can realize high reversible zinc plating/stripping behavior, and full cell using this zinc plated substrate can be operated for more than 1000 cycles with high capacity retention (85.3%) and low electrochemical impedance. The proposed strategy can be also applied to lithium metal batteries, which demonstrates that the substrate orientation regulation and metal affinity design are the promising approaches to achieve dendrite-free metal anode and overcome the challenges of highly reactive metal anodes.
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Zehendner, Christoph M., Heiko J. Luhmann, and Christoph RW Kuhlmann. "Studying the Neurovascular Unit: An Improved Blood–Brain Barrier Model." Journal of Cerebral Blood Flow & Metabolism 29, no. 12 (2009): 1879–84. http://dx.doi.org/10.1038/jcbfm.2009.103.
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The blood–brain barrier (BBB) closely interacts with the neuronal parenchyma in vivo. To replicate this interdependence in vitro, we established a murine coculture model composed of brain endothelial cell (BEC) monolayers with cortical organotypic slice cultures. The morphology of cell types, expression of tight junctions, formation of reactive oxygen species, caspase-3 activity in BECs, and alterations of electrical resistance under physiologic and pathophysiological conditions were investigated. This new BBB model allows the application of techniques such as laser scanning confocal microscopy, immunohistochemistry, fluorescent live cell imaging, and electrical cell substrate impedance sensing in real time for studying the dynamics of BBB function under defined conditions.
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Samanta, Gopinath, and Sekhar Ranjan Bhadra Chaudhuri. "DESIGN OF A COMPACT CP ANTENNA WITH ENHANCED BANDWIDTH USING A NOVEL HEXAGONAL RING BASED REACTIVE IMPEDANCE SUBSTRATE." Progress In Electromagnetics Research M 69 (2018): 115–25. http://dx.doi.org/10.2528/pierm18041004.
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Andrews, George, Olga Neveling, Dirk Johannes De Beer, Evans M. N. Chirwa, Hendrik G. Brink, and Trudi-Heleen Joubert. "Non-Destructive Impedance Monitoring of Bacterial Metabolic Activity towards Continuous Lead Biorecovery." Sensors 22, no. 18 (2022): 7045. http://dx.doi.org/10.3390/s22187045.
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The adverse health effects of the presence of lead in wastewater streams are well documented, with conventional methods of lead recovery and removal suffering from disadvantages such as high energy costs, the production of toxic sludge, and low lead selectivity. Klebsiella pneumoniae and Paraclostridium bifermentans have been identified as potential lead-precipitating species for use in a lead recovery bioreactor. Electrical impedance spectroscopy (EIS) on a low-cost device is used to determine the potential for the probe-free and label-free monitoring of cell growth in a bioreactor containing these bacteria. A complex polynomial is fit for several reactive equivalent circuit components. A direct correlation is found between the extracted supercapacitance and the plated colony-forming unit count during the exponential growth phase, and a qualitative correlation is found between all elements of the measured reactance outside the exponential growth phase. Strong evidence is found that Pb(II) ions act as an anaerobic respiration co-substrate for both cells observed, with changes in plated count qualitatively mirrored in the Pb(II) concentration. Guidance is given on the implementation of EIS devices for continuous impedance monitoring.
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Mejía, Claudia P., Henry S. Vanegas, and Jhon J. Olaya. "Electrochemical and Optical Behavior of ZrN-Ag Coatings Deposited by Means of DC Reactive Magnetron Sputtering Technique." Coatings 12, no. 6 (2022): 754. http://dx.doi.org/10.3390/coatings12060754.
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The formation of nanostructured transition metal nitride coatings by introducing a small amount of silver (Ag) content has been proven to be a good strategy for enhancing the physical properties of these materials. In this investigation, ZrN coatings with different Ag contents were deposited on an AISI 316L substrate using the DC reactive magnetron sputtering technique. The influence of the silver on the chemical composition, morphology, and microstructure was investigated using energy-dispersive X-ray spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and X-ray diffraction (XRD). The functional properties, specifically the corrosion resistance and the optical reflectance of the deposited coatings, were investigated using electrochemical impedance spectroscopy (EIS) and UV-Visible-NIR, respectively. The results showed the formation of two nanocrystalline phases, fcc-ZrN and metallic fcc-Ag. On the surface of the deposited coatings, homogeneously distributed silver nanoparticles were observed, and they increased with the Ag atomic content. The chemical composition on the surface showed evidence of the formation of oxides, such as Zr-O and Zr-O-N, before and after the corrosion tests. The corrosion resistance of the AISI 316L substrate and the coatings was improved with the incorporation of Ag, and the optical reflectance increased with increasing the Ag content. Finally, this work investigated the effect of the incorporation of silver into a ZrN matrix for potential use as optical protective coatings.
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Rabadzhiyska, Stanislava, Dimitar Dechev, Nikolay Ivanov, et al. "Wear and Corrosion Resistance of ZrN Coatings Deposited on Ti6Al4V Alloy for Biomedical Applications." Coatings 14, no. 11 (2024): 1434. http://dx.doi.org/10.3390/coatings14111434.
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Zirconium nitrides films were synthesized on Ti6Al4V substrates at a bias voltage of −50 V, −80 V, −110 V and −150 V by the direct current (DC) reactive magnetron sputtering technique. The as-deposited coatings were characterized by X-ray diffraction (XRD), Fourier-transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM) and atomic force microscopy (AFM). The wear and corrosion resistance of the obtained ZrN coatings were evaluated to determine the possibility for their implementation in modern biomedical applications. It was found that the intensity of the diffraction peak of the Zr-N phase corresponding to the (1 1 1) crystallographic plane rose as the bias voltage increased, while the ZrN coatings’ thickness reduced from 1.21 µm to 250 nm. The ZrN films’ surface roughness rose up to 75 nm at −150 V. Wear tests showed an increase in the wear rate and wear intensity as the bias voltage increased. Corrosion studies of the ZrN coatings were carried out by three electrochemical methods: open circuit potential (OCP), cyclic voltammetry (polarization measurements) and electrochemical impedance spectroscopy (EIS). All electrochemical measurements confirmed that the highest protection to corrosion is the ZrN coating, which was deposited on the Ti6Al4V substrate at a bias voltage of −150 V.
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Carneiro, Edgar, José David Castro, Maria José Lima, Jorge Ferreira, and Sandra Carvalho. "Corrosion Resistance in Artificial Perspiration of Cr-Based Decorative Coatings." Nanomaterials 13, no. 16 (2023): 2346. http://dx.doi.org/10.3390/nano13162346.
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We aim at developing hexavalent chromium-free coatings for frequently touched decorative parts. Cr(N,O) and multilayered CrN/CrO coatings were deposited by means of reactive magnetron sputtering. All samples presented good adhesion to the substrates enhanced by an epoxy layer designed to enhance PVD coating adhesion. Similar substrates are found in the automotive industry and can be used in appliances where a metallic finish is desired by the consumer. Corrosion behavior was induced, using artificial sweat to simulate long exposure to human touch for 96 h. In potentiodynamic polarization tests, the coatings were revealed to be nobler than the substrate alone. Cr displayed a non-existent passivation region, while gCrN exhibited a quick passivation of the surface and its respective breakdown and several current fluctuations, indicating the occurrence of pitting, which was confirmed by SEM micrography after the corrosion. Regarding EIS results, all films depicted a diminution of impedance modulus (|Z|) after 96 h, which indicates a diminution of corrosion resistance against artificial sweat. Nitride films exhibited the worst anticorrosive features. On the other hand, Cr and CrO exhibited the highest |Z| values. These results are corroborated by low the corrosion rates of both coatings. The equivalent electrical circuit allows us to confirm oxide formation in the outermost layer of the films due to electrolyte/surface interaction, indicating a self-protecting mechanism. Nitride films showed the lowest values and less corrosion resistance, confirming the results obtained in polarization potentiodynamic tests. The coatings developed in this work, namely Cr and CrO, showed a promising corrosion resistance behavior that could endure a lifetime of frequent human touch in various decorative applications either automotive or general appliances.
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Chilukuri, Sulakshana, and Srividya Gundappagari. "A Wide Dual-Band Metamaterial-Loaded Antenna for Wireless Applications." Journal of Electromagnetic Engineering and Science 20, no. 1 (2020): 23–30. http://dx.doi.org/10.26866/jees.2020.20.1.23.
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A compact, wide dual-band antenna designed to resonate at 2.25 GHz and 5.4 GHz is proposed in this paper. The proposed antenna is a monopole rectangular patch designed to operate at 5 GHz. This basic structure is modified by introducing a metamaterial-based interdigital capacitor reactive loading that exhibits dual-band characteristics at 2.25 GHz and 5.4 GHz. A bandwidth greater than 1.4 GHz at the two resonant frequencies is obtained. The compact size of the proposed antenna is 0.0989λ<sub>0</sub> × 0.0498λ<sub>0</sub>, where λ<sub>0</sub> is calculated at the first resonance. The antenna is etched on a FR4 substrate with dielectric constant <i>ɛ</i><sub><i>r</i></sub> = 4.4 and thickness of 1.6 mm. The simulated results exhibit considerable gain and wide impedance bandwidth at the resonant frequencies. Monopole-like radiation patterns are obtained at both the operating frequencies. The designed antenna can be applied in wireless local area networks and Wi-MAX wireless communications.
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Aznar-Ballesta, Francisco, Jordi Selga, Paris Vélez, et al. "Slow-wave coplanar waveguides based on inductive and capacitive loading and application to compact and harmonic suppressed power splitters." International Journal of Microwave and Wireless Technologies 10, no. 5-6 (2017): 530–37. http://dx.doi.org/10.1017/s1759078717001350.
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In this paper, a slow-wave transmission line implemented in coplanar waveguide technology, based on simultaneous inductive and capacitive loading, is presented for the first time. The shunt capacitors are achieved by periodically etching transverse strips in the back substrate side, connected to the central strip through metallic vias. The series inductors are implemented by etching rectangular slots in the ground plane. The effect of these reactive elements is an enhancement of the effective shunt capacitance and series inductance of the line, leading to a significant reduction of the phase velocity (slow-wave effect). Consequently, the guided wavelength is also reduced, and these lines can be applied to the miniaturization of microwave components. Moreover, due to periodicity, these artificial lines exhibit stop bands (Bragg effect) useful for spurious or harmonic suppression. A compact harmonic suppressed power splitter, based on a slow wave 35.35 Ω impedance inverter, has been designed and fabricated in order to demonstrate the potential of the proposed approach. The length of the inverter is 48% the length of the conventional counterpart, and measured power splitting at the first (3f0) and second (5f0) harmonic frequencies is rejected more than 49 and 23 dB, respectively.
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Lanznaster, Débora, Caio M. Massari, Vendula Marková, et al. "Adenosine A1-A2A Receptor-Receptor Interaction: Contribution to Guanosine-Mediated Effects." Cells 8, no. 12 (2019): 1630. http://dx.doi.org/10.3390/cells8121630.
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Guanosine, a guanine-based purine nucleoside, has been described as a neuromodulator that exerts neuroprotective effects in animal and cellular ischemia models. However, guanosine’s exact mechanism of action and molecular targets have not yet been identified. Here, we aimed to elucidate a role of adenosine receptors (ARs) in mediating guanosine effects. We investigated the neuroprotective effects of guanosine in hippocampal slices from A2AR-deficient mice (A2AR−/−) subjected to oxygen/glucose deprivation (OGD). Next, we assessed guanosine binding at ARs taking advantage of a fluorescent-selective A2AR antagonist (MRS7396) which could engage in a bioluminescence resonance energy transfer (BRET) process with NanoLuc-tagged A2AR. Next, we evaluated functional AR activation by determining cAMP and calcium accumulation. Finally, we assessed the impact of A1R and A2AR co-expression in guanosine-mediated impedance responses in living cells. Guanosine prevented the reduction of cellular viability and increased reactive oxygen species generation induced by OGD in hippocampal slices from wild-type, but not from A2AR−/− mice. Notably, while guanosine was not able to modify MRS7396 binding to A2AR-expressing cells, a partial blockade was observed in cells co-expressing A1R and A2AR. The relevance of the A1R and A2AR interaction in guanosine effects was further substantiated by means of functional assays (i.e., cAMP and calcium determinations), since guanosine only blocked A2AR agonist-mediated effects in doubly expressing A1R and A2AR cells. Interestingly, while guanosine did not affect A1R/A2AR heteromer formation, it reduced A2AR agonist-mediated cell impedance responses. Our results indicate that guanosine-induced effects may require both A1R and A2AR co-expression, thus identifying a molecular substrate that may allow fine tuning of guanosine-mediated responses.
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Serna-Manrique, Milton David, Daniel Escobar-Rincón, Santiago Ospina-Arroyave, Daniel Alejandro Pineda-Hernández, Yury Paola García-Gallego, and Elisabeth Restrepo-Parra. "Growth Mechanisms of TaN Thin Films Produced by DC Magnetron Sputtering on 304 Steel Substrates and Their Influence on the Corrosion Resistance." Coatings 12, no. 7 (2022): 979. http://dx.doi.org/10.3390/coatings12070979.
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In this work, thin films of TaN were synthesized on 304 steel substrates using the reactive DC sputtering technique from a tantalum target in a nitrogen/argon atmosphere. All synthesis parameters such as gas ratio, pressure, gas flow, and substrate distance, among others, were fixed except the applied power of the source for different deposited coatings. The effect of the target power on the formation of the resulting phases and the microstructural and morphological characteristics was studied using XRD and AFM techniques, respectively, in order to understand the growth mechanisms. Phase, line profile, texture, and residual stress analysis were carried out from the X-ray diffraction patterns obtained. Atomic force microscopy analysis allowed us to obtain values for surface grain size and roughness which were related to growth mechanisms in accordance with XRD results. Results obtained showed a strong correlation between the growth energy with the crystallinity of the samples and the formation of the possible phases since the increase in the growth power caused the samples to evolve from an amorphous structure to a cubic monocrystalline structure. For all produced samples, the δ-TaN phase was observed despite the low N2 content used in the process (since for low N2 content it was expected to be possible to obtain films with α-Ta or hexagonal ε-TaN crystalline structure). In order to determine the corrosion resistance of the coatings, electrochemical impedance spectroscopy and polarization resistance were employed in the Tafel region. The results obtained through this evaluation showed a direct relationship between the power used and the improvement of the properties against corrosion for specific grain size values.
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Mthiyane, Khethiwe, Gloria Ebube Uwaya, Maryam Amra Jordaan, Suvardhan Kanchi, and Krishna Bisetty. "Insights into the Design of An Enzyme Free Sustainable Sensing Platform for Efavirenz." Catalysts 12, no. 8 (2022): 830. http://dx.doi.org/10.3390/catal12080830.
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In this study, a new hybrid sensor was developed using titanium oxide nanoparticles (TiO2-NPs) and nafion as an anchor agent on a glassy carbon electrode (GCE/TiO2-NPs-nafion) to detect efavirenz (EFV), an anti-HIV medication. TiO2-NPs was synthesized using Eucalyptus globulus leaf extract and characterized using ultraviolet–visible spectroscopy (UV–VIS), scanning electron microscopy (SEM), X-ray diffraction (XRD), and energy-dispersive spectroscopy (EDS). The electrochemical and sensing properties of the developed sensor for EFV were assessed using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The current response of GCE/TiO2-NPs-nafion electrode towards the oxidation of EFV was greater compared to the bare GCE and GCE/TiO2-NPs electrodes. A linear dynamic range of 4.5 to 18.7 µM with 0.01 µM limit of detection was recorded on the electrode using differential pulse voltammetry (DPV). The electrochemical sensor demonstrated good selectivity and practicality for detecting EFV in pharmaceuticals (EFV drugs) with excellent recovery rates, ranging from 92.0–103.9%. The reactive sites of EFV have been analyzed using quantum chemical calculations based on density functional theory (DFT). Monte Carlo (MC) simulations revealed a strong electrostatic interaction on the substrate-adsorbate (GCE/TiO2-NPs-nafion-EFV) system. Results show good agreement between the MC computed adsorption energies and the experimental CV results for EFV. The stronger adsorption energy of nafion onto the GCE/TiO2-NPs substrate contributed to the catalytic role in the signal amplification for sensing of EFV. Our results provide an effective way to explore the design of new 2D materials for sensing of EFV, which is highly significant in medicinal and materials chemistry.
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Deng, Peichang, Juyu Shangguan, Jiezhen Hu, Baoyu Geng, and Peilin Wang. "Effect of Barnacles on the Corrosion Behavior of 304 Stainless Steel." Metals 13, no. 10 (2023): 1649. http://dx.doi.org/10.3390/met13101649.
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Wire-beam, potentiodynamic polarization, electrochemical impedance spectroscopy and surface corrosion morphology analysis techniques were used to investigate the corrosion characteristics of 304 stainless steel (304SS) specimens subjected to different degrees of fouling; these analyses were conducted to clarify the corrosive effects of biofilms and barnacles. The experimental results indicated that the gradual thickening of the biofilm reduces the corrosion rate of 304SS (Icorr = 0.0677 μA/cm2). Mature biofilm acts as a barrier and significantly increases the protection of the substrate (Z = 905,000 Ω·cm2). The corrosion mechanisms of 304SS fouled with barnacles at various stages of growth are distinct: the corrosion rates of the microelectrodes fouled by living and recently dead barnacles are low because the overall structure is still intact. This structure creates a closed environment between the barnacles and the metal, limiting the transfer of corrosive factors from the outside to the inside. Despite the influences of corrosive bacterial decomposition, the Ecorr values of recently dead barnacles dramatically decrease to −668.8 mV. The microelectrode covered by the empty-shell barnacles corrodes heavily. Bacteria decompose the barnacle body and calcite shell, and glue damages their originally closed structures. Direct contact between the metal and reactive ions occurs, resulting in the continuous ingress of Cl− into the cracks, which intensifies crevice corrosion.
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Mejia Chueca, María del Carmen, Christoph Baumer, Michael Stich, Adriana Ispas, and Andreas Bund. "Electrodeposition of Reactive Aluminum-Nickel Coatings in an AlCl3:[Emim]Cl Ionic Liquid Containing Nickel Nanoparticles." ECS Meeting Abstracts MA2023-02, no. 56 (2023): 2716. http://dx.doi.org/10.1149/ma2023-02562716mtgabs.
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The electrodeposition of reactive aluminum-nickel dispersion coatings was performed by pulsed direct current (PDC) onto copper substrates in the ionic liquid 1.5:1 AlCl3:[EMIm]Cl (1-Ethyl-3-methylimidazolium chloride). A cathodic current density of 15 mA/cm2 was used with two different frequency (f)/duty cycle (r c) combinations, i.e., f= 0.33 Hz/ r c= 0.33 (t on= 1 s, t off= 2 s) and f= 0.05 Hz/ r c= 0.5 (t on= 10 s, t off= 10 s). Several electrochemical techniques like Cyclic Voltammetry, Electrochemical Impedance Spectroscopy and Open Circuit Potential measurements were used besides X-Ray Diffraction, Confocal Microscopy, Scanning Electron Microscopy, Atomic Absorption Spectroscopy and 27Al/1H Nuclear Magnetic Resonance in order to shed more light on the mechanism of Ni particle incorporation into the Al metal matrix. We could show that particle incorporation at the beginning of the deposition mainly takes place via particle adsorption at the substrate. As the thickness of the coating increases, it seems that the main mechanism for particle incorporation is via the reduction of Al2Cl7 - ions adsorbed at the particles surface. Three different Ni NPs concentration were tested in this work: 5, 10 and 20 g/L. Although a considerable high incorporation of Ni NPs has been achieved from the IL electrolyte containing the highest concentration of Ni NPs (i.e. ~ 33 wt.% from a 20 g/L of Ni NPs bath), a high concentration of NPs in the ionic liquid resulted having a negative effect in terms of quality of the coatings, due to local cathodic passivation, or solidification of the electrolyte in a poorly conductive compound. This phenomenon has been related to the increase in viscosity originating from the decrease in rotational mobility of the [EMIm]+ cation, as detected by 1H NMR. Despite this fact, almost equivalent amounts of Ni and Al (Ni ~ 45 wt.% and Al ~ 44 wt.%) have been detected by energy-dispersive X-ray spectroscopy mapping in some areas of the coatings prepared with longer pulse off-time (f = 0.05 Hz, t off= 10 s). Such a layer composition would be convenient for the targeted application. Nevertheless, more studies related to the homogeneity of the deposits, as well as ignition tests, must be performed to evaluate the suitability of the coatings to trigger a self-propagating reaction.
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Sun, Wei, Hai Sheng San, Ying Xian Duo, and Xu Yuan Chen. "Preparation and Characterization of Micro Polypyrrole Electrodes for Supercapacitor." Advanced Materials Research 60-61 (January 2009): 375–79. http://dx.doi.org/10.4028/www.scientific.net/amr.60-61.375.
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A novel electrode of supercapacitor was developed with a three dimensional (3D) structure which results in a significant increase of the electrode area per unit capacitor volume. An area of 2.58 times the area of corresponding planar design was obtained. The process flow for fabricating the 3D electrode was developed compatible with microelectromechanical system technology. The key processes were high-aspect-ratio Deep Reactive Ion Etching, electroless plating and electropolymerization. Ni as the current collector was deposited on Si/SiO2 substrate by using electroless plating, Polypyrrole was galvanostatically polymerized as electroactive film. The capacitance properties of the 3D electrode were investigated. Cyclic voltammetry tests show that the specific capacitance of the 3D electrode at 100 mV/s was 0.014 F/cm2 which is comparable with the 0.013 F/cm2 for the planar design. Electrochemical impedance spectroscopy plot of the 3D electrode is well fitted by equivalent circuit, we found the specific capacitance is 0.011 F/cm2 which is slightly larger than 0.0094 F/cm2 for similarly planar design. From the gavanostatic charge/discharge tests, the specific capacitance of the 3D electrode at 2 mA/cm2 is 0.011 F/cm2 while for planar design the corresponding value is 0.010 F/cm2. The results indicate the continuous and homogeneous Polypyrrole film with 3D structure was obtained as we designed.
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Lee, Rose Yesl, Jun Liu, and Daniel T. Schwartz. "Facile Characterization of the Lithium Metal/Electrolyte Interface through Nonlinear Electrochemical Impedance Spectroscopy." ECS Meeting Abstracts MA2024-02, no. 7 (2024): 923. https://doi.org/10.1149/ma2024-027923mtgabs.
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Next-generation lithium metal batteries have demonstrated the high energy densities necessary for electric vehicles and thus have the potential to enable the widespread electrification of transportation.1 However, mass adaptation of lithium metal batteries is challenged by the unsatisfactory cycle life resulting from the lack of electrolytes compatible with the highly reactive lithium metal surface. The uncontrolled interactions between the lithium anode and the electrolyte results in the continuous depletion of both participants and/or the formation of electrically isolated lithium, which ultimately reduces the cycle life. While progress in electrolyte engineering offers hints on the role of the electrolyte in essential battery processes (eg., the formation of a stable solid-electrolyte interphase layer and favorable deposited lithium morphologies), further improvements in lithium metal batteries necessitates a deeper understanding of the lithium metal/electrolyte interface. The performance of lithium metal battery electrolytes is often gauged by the ratio between the discharge and charge capacities, or the Coulombic efficiency (CE). An electrolyte with a high CE indicates that the discharge and charge capacities were nearly equal, or that very little lithium was lost to undesirable side processes during cycling. A typical CE experiment, such as the popular Aurbach method, involves several cycles of plating and stripping a lithium reservoir from a copper substrate at one current density.2 With hundreds of cycles, a single CE test can be time-consuming, presenting a bottleneck in electrolyte research. Here, we integrate nonlinear electrochemical impedance spectroscopy (NLEIS) into a modified Aurbach method to evaluate the evolution of the lithium metal/electrolyte interface with cycling and detect earlier signs of lower CE electrolytes. With the same instrumentation as its linear counterpart, NLEIS utilizes a moderate AC current amplitude to elicit a weakly nonlinear voltage response that is sensitive to kinetic, transport, and thermodynamic processes. Notably, the second harmonic voltage response is formed by the differences between the battery electrodes, making NLEIS a powerful diagnostic tool for detecting subtle changes.3,4 This work introduces a methodology that could enable faster characterization of lithium metal electrolytes, yet opens the path for more in-depth kinetic studies. G. M. Hobold et al., Nat. Energy, 6, 951–960 (2021). B. D. Adams, J. Zheng, X. Ren, W. Xu, and J. G. Zhang, Adv. Energy Mater., 8, 1–11 (2018). Y. Ji and D. T. Schwartz, J. Electrochem. Soc., 170, 123511 (2023). 4. Y. Ji and D. T. Schwartz, J. Electrochem. Soc., 171, 023504 (2024). Figure 1
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Meléndez-Campos, Javier, Matias Vázquez-Piñón, and Sergio Camacho-Leon. "Sensitivity Analysis of a Portable Wireless PCB-MEMS Permittivity Sensor Node for Non-Invasive Liquid Recognition." Micromachines 12, no. 9 (2021): 1068. http://dx.doi.org/10.3390/mi12091068.
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Dielectric characteristics are useful to determine crucial properties of liquids and to differentiate between liquid samples with similar physical characteristics. Liquid recognition has found applications in a broad variety of fields, including healthcare, food science, and quality inspection, among others. This work demonstrates the fabrication, instrumentation, and functionality of a portable wireless sensor node for the permittivity measurement of liquids that require characterization and differentiation. The node incorporates an interdigitated microelectrode array as a transducer and a microcontroller unit with radio communication electronics for data processing and transmission, which enable a wide variety of stand-alone applications. A laser-ablation-based microfabrication technique is applied to fabricate the microelectromechanical systems (MEMS) transducer on a printed circuit board (PCB) substrate. The surface of the transducer is covered with a thin layer of SU-8 polymer by spin coating, which prevents it from direct contact with the Cu electrodes and the liquid sample. This helps to enhance durability, avoid electrode corrosion and contamination of the liquid sample, and to prevent undesirable electrochemical reactions to arise. The transducer’s impedance was modeled as a Randles cell, having resistive and reactive components determined analytically using a square wave as stimuli, and a resistor as a current-to-voltage converter. To characterize the node sensitivity under different conditions, three different transducer designs were fabricated and tested for four different fluids, i.e., air, isopropanol, glycerin, and distilled water—achieving a sensitivity of 1.6965 +/− 0.2028 εr/pF. The use of laser ablation allowed the reduction of the transducer footprint while maintaining its sensitivity within an adequate value for the targeted applications.
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Brailoiu, Eugen, Jeffrey L. Barr, Hailey N. Wittorf, Saadet Inan, Ellen M. Unterwald, and Gabriela Cristina Brailoiu. "Modulation of the Blood–Brain Barrier by Sigma-1R Activation." International Journal of Molecular Sciences 25, no. 10 (2024): 5147. http://dx.doi.org/10.3390/ijms25105147.
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Sigma non-opioid intracellular receptor 1 (Sigma-1R) is an intracellular chaperone protein residing on the endoplasmic reticulum at the mitochondrial-associated membrane (MAM) region. Sigma-1R is abundant in the brain and is involved in several physiological processes as well as in various disease states. The role of Sigma-1R at the blood–brain barrier (BBB) is incompletely characterized. In this study, the effect of Sigma-1R activation was investigated in vitro on rat brain microvascular endothelial cells (RBMVEC), an important component of the blood–brain barrier (BBB), and in vivo on BBB permeability in rats. The Sigma-1R agonist PRE-084 produced a dose-dependent increase in mitochondrial calcium, and mitochondrial and cytosolic reactive oxygen species (ROS) in RBMVEC. PRE-084 decreased the electrical resistance of the RBMVEC monolayer, measured with the electric cell-substrate impedance sensing (ECIS) method, indicating barrier disruption. These effects were reduced by pretreatment with Sigma-1R antagonists, BD 1047 and NE 100. In vivo assessment of BBB permeability in rats indicates that PRE-084 produced a dose-dependent increase in brain extravasation of Evans Blue and sodium fluorescein brain; the effect was reduced by the Sigma-1R antagonists. Immunocytochemistry studies indicate that PRE-084 produced a disruption of tight and adherens junctions and actin cytoskeleton. The brain microcirculation was directly visualized in vivo in the prefrontal cortex of awake rats with a miniature integrated fluorescence microscope (aka, miniscope; Doric Lenses Inc.). Miniscope studies indicate that PRE-084 increased sodium fluorescein extravasation in vivo. Taken together, these results indicate that Sigma-1R activation promoted oxidative stress and increased BBB permeability.
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Saliba-Silva, Adonis M., R. H. L. Garcia, I. C. Martins, E. F. Urano de Carvalho, and M. Durazzo. "Nickel Electrodeposition over Powder Compact for Irradiation Target." Materials Science Forum 727-728 (August 2012): 14–19. http://dx.doi.org/10.4028/www.scientific.net/msf.727-728.14.
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rradiation targets with 20% of 235U (Low Enriched Uranium - LEU) have been studied to replace HEU (Highly Enriched Uranium) targets in future nuclear reactors. These are used to produce the pair of radionuclides 99Mo / 99mTc, used for diagnostics in nuclear medicine. This work aims to develop an alternative route to produce LEU targets. It consists in hydrogenating and powdering metallic uranium and compacting the produced powder, followed by sealing it with nickel by electrodeposition. The deposited nickel should suppress the release of fission gases, and avoid a reactive contact of uranium with aluminum from the enclosure. In order to obtain the best conditions for deposition over uranium, in this work iron powder was compacted into small discs, with a diameter of 22mm and weight of 14g, simulating an equivalent volume of 10g of LEU uranium powder. As well, aluminum discs were used to ensure adhesion and uniformity of the nickel layer. Pulsed nickel electrodeposition was carried out over the compacts, employing current frequency of 900Hz, -0.84A/cm2 of peak current and duty cycle of 0.5 in Watts Bath. The electrical resistance of pulse Ni-plated layer was checked by experiments with impedance spectroscopy in plated samples using aluminum substrate, held in KCl (pH=6), giving EIS results after resting the discs in solution for 0h, 4h and 24h. The physical strength was evaluated qualitatively by treating the Ni covered compact at 600°C, developing a bump deformation on the original planar layer, up to the point to open the Ni-layer for gas relief. These results suggest an adequate mechanical strength of the Ni-layer for using under neutronic irradiation, sealing the radioactive gases, mainly 140Xe, produced during fission of 235U.
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Wu, X., X. Xu, JG Garcia, and T. Wang. "ID: 129: PARTICULATE MATTER DISRUPTS ENDOTHELIAL CELL PERMEABILITY VIA GAP JUNCTION PROTEIN." Journal of Investigative Medicine 64, no. 4 (2016): 970.2–971. http://dx.doi.org/10.1136/jim-2016-000120.124.
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IntroductionParticulate matter (PM) is significantly associated with cardiopulmonary morbidity and mortality. We previously demonstrated that PM induces endothelial barrier disruption via reactive oxygen species (ROS)-dependent mechanisms. This study is focused on characterization of PM-regulated endothelial dysfunction via connexin43 (Cx43), a Gap junction protein. Gap junction is designated as intercellular channel which allows cells to communicate with each other, share nutrients, and transfer chemical or electrical signals, in turn, enables cells in a tissue to function in a coordinated manner.Methods and ResultsCx43 protein levels were evaluated by western blotting, and band density quantified using MyImageAnalysis. Real-time PCR was conducted to determine Cx43 mRNA levels. Human pulmonary artery endothelial cell (EC) barrier function was measured using the electrical cell-substrate impedance sensing (ECIS) system (Applied Biophysics) that provides a readout of transendothelial electrical resistance (TER). PM sample (0.1–0.3 µm of aerodynamic diameter) was collected (April of 2005) from the Ft. McHenry Tunnel, Baltimore, MD using a high-volume cyclone collector. PM (100 µg/ml) induced time-dependent increases in EC Cx43 mRNA levels (∼5 fold increase at 4 hr) and protein expression which was attenuated by N-acetyl-cysteine (NAC, 5 mM, 1 hr pretreatment), an ROS scavenger. Unlike Cx43, Cx37, another connexin expressed in ECs, remained unaltered by PM challenge. In addition, EC pretreatment with a Cx43 inhibitor, connexin-mimetic peptide Gap27 (500 µM, 2 hr pretreatment), significantly attenuated PM-reduced TER reduction by 45%, suggesting a central role of Cx43 in PM-induced lung EC barrier integrity disruption and signal transduction.ConclusionsOur results suggest Cx43 as a key and novel participant in PM-mediated signal transduction that results in loss of vascular barrier integrity. Cx43 may serve as a therapeutic target in PM-induced cardiopulmonary toxicities.
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Ghaedamini, Hamidreza, Ana Alba-Rubio, and Dong-Shik Kim. "A Novel Cerium Oxide/Gold/Carbon Nanocomposite-Based Electrochemical Sensor for Detecting Hydroxyl Radicals." ECS Meeting Abstracts MA2024-01, no. 49 (2024): 2684. http://dx.doi.org/10.1149/ma2024-01492684mtgabs.
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Hydroxyl radicals (•OH), a type of reactive oxygen species (ROS), play a crucial role in maintaining the normal physiological processes of human cells. Nevertheless, an excessive accumulation of these radicals may perturb cellular mechanisms, so triggering the onset of severe diseases, including cancer, neurological disorders, and heart disease. The detection of •OH is thus of utmost importance in the early diagnosis of these disorders. The combination of an electrochemical methodology with a recognition system is considered as a promising approach for the detection of •OH. This is primarily due to its capacity to provide fast and direct readings without the need for any preliminary sample preparation. This study presents the development of a new electrochemical sensor for the detection of •OH. The sensor was developed by modifying a screen-printed carbon electrode (SPCE) with a nanocomposite consisting of cerium oxide nanoclusters (CeOx), gold nanoparticles (AuNPs), and a highly conductive carbon. The synthesis of AuNPs supported by carbon was carried out using a deposition-precipitation process. Subsequently, the meticulous deposition of CeOx nanoclusters onto the AuNPs was achieved by the use of surface organometallic chemistry (SOMC). Energy dispersive X-ray spectroscopy (EDS) and transmission electron microscopy (TEM) were applied to assess the distribution of AuNPs on the carbon substrate and their subsequent embellishment with CeOx nanoclusters. The actual loadings of Ce and Au present in the nanocomposite were measured using inductively coupled plasma optical emission spectroscopy (ICP-OES). Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were employed to analyze the electrochemical responses resulting from the interaction of the CeOx-Au/Carbon nanocomposite with •OH. The CV results demonstrated that the proposed sensor exhibited the capability to effectively identify the presence of •OH in the Fenton reaction, with a notably low limit of detection of 58 µM. The sensor demonstrated a linear correlation between the current response and the concentration of •OH, within the range of 0.05 to 5 mM. Compared to a sensor modified with CeOx/Carbon, the CeOx-Au/Carbon-modified sensor exhibited enhanced electrochemical performance, as demonstrated by an increased current response and a reduced peak potential difference when detecting •OH radicals. Furthermore, the EIS studies showed that the sensor could distinguish •OH from other comparable ROS, such as hydrogen peroxide (H2O2).
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Naranjo, Santiago, Lina Castañeda, Luis Daniel Salazar Hoyos, Carlos Ignacio Sanchez, and Luisa Maria Alvarez Gonzalez. "Synthesis of ZnO Nanorods-Based Photoanode and Electrochemical Characterization for Azoic Dyes Degradation: Reactive Red 239 Study Case." ECS Meeting Abstracts MA2022-02, no. 54 (2022): 2012. http://dx.doi.org/10.1149/ma2022-02542012mtgabs.
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The use of solar energy as an energy vector has been a subject of great interest and study in recent years, showing vast improvements in the efficiencies associated with the conversion to electrical energy. This interest has extended to various applications, among which the production of green hydrogen from the decomposition of water and in environmental remediation processes stand out. The main motivation in focusing the use of solar energy in photoelectrocatalytic degradation processes is the negative impact that the disposal of colored water has on the different effluents, causing a deterioration of the quality of these ecosystems and the death of many forms of life. In this sense, the application of semiconductors based on zinc oxide (ZnO) supported on FTO conductive glass was studied for the treatment of wastewater from the textile industry, contaminated with reactive red azo dye 239. The main motivation in focusing the use of solar energy in photoelectrocatalytic degradation processes is the negative impact that the disposal of colored water effluents has on the different ecosystems, causing a deterioration of the quality of these ecosystems and the death of many forms of life. In this sense, the application of semiconductors based on zinc oxide (ZnO) supported on FTO was studied for the treatment of wastewater from the textile industry, contaminated with reactive red azo dye 239. In the present writing, a process for the synthesis of a ZnO-based semiconductor was defined. This precedence was performed directly on the substrate of 15x15x1.1mm FTO conductive glass plates. Prior to the synthesis process, a pretreatment of the glass is performed. The pretreatment of the plates consists of washing with neutral soap, then immersion in 0.01 M nitric acid (HNO3) for 10 minutes, and finally, cleaning with deionized water in ultrasound for 10 minutes. The synthesis of the nanostructured ZnO was performed in two steps. First, a chronoamperometric electrodeposition of the ZnO seeds on the substrate at a fixed potential of -1.38 V vs. Ag/AgCl as reference, and a platinum electrode as counter electrode, was performed at 70ºC for 200 seconds with a Gamry® Interface 1000 potentiostat, then subjected to a heating period at 400ºC for 2 hours. After electronucleation of the seeds and heat treatment, an additional step is carried out, which is the chemical growth of ZnO, waiting for the formation of ZnO nanorods in the (100), (002) and (101) planes typical of the wurtzite structure, this is done in a zinc nitrate solution at 90ºC, pH > 13.5, for 75 minutes. In the semiconductor characterization, different electrochemical techniques such as cyclic voltammetry, electrochemical impedance spectroscopy and anodic linear scanning were evaluated. At the same time, the response of the photoanode to illumination with a 350 W xenon arc lamp was studied, showing the remarkable effect of light on the generation of charge carriers, decreasing recombination, and increasing photocurrents. On the other hand, the density of charge carriers in the semiconductor was evaluated and defined, as well as the position of the valence and conduction bands and their respective band gap. The charge carrier density was determined from Mott-Schottky, finding densities of 6.25x1021 and 3.72x1021 carriers/cm3, for frequencies of 500 and 1000 Hz, respectively. In parallel, the flat band potential, which under certain circumstances of charge carrier density can approximate the conduction band potential, was evaluated. This was estimated from three methods, Mott-Schottky (500 and 1000 Hz), photocurrent onset potential and open circuit potential, finding values of -0.086 and -0.124 (at 500 and 1000 Hz), -0.121 and -0.161 V vs. Ag/AgCl, respectively. The determination of the bad gap was performed from UV-VIS, obtaining a value of 3.13 eV. Finally, the discoloration of the solution was evaluated from UV-VIS measurements. This analysis was performed on a problem solution that resembles the concentration of dye and salts of a textile industry effluent. A ZnO electrode was used, with a defined working area of 1.30 cm2, and a dye volume of 25 mL. The experiment was carried out for a time period of 4 hours, and an applied potential of 1 V vs. Ag/AgCl/Cl- 3M, reaching a decolorization of 23.2% of the initial solution.
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Manzoor, Muhammad Umar, Faraz Hussain, Hafsa Zafar, et al. "Electrochemical Characterization of AlTiN Coating on Stainless Steel Substrate for Biomedical Implant." Journal of the Pakistan Institute of Chemical Engineers 48, no. 2 (2021): 9–16. http://dx.doi.org/10.54693/piche.04822.
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Physical Vapor Deposition technology is an established technique to deposit metallic and ceramic coatings on different metallic substrates. Lateral Arc Rotating Cathode (LARC) technology has an added advantages of better mechanical uniform coating, consistent erosion of the electrodes and greater degree of ionization. LARC technology was used to deposit AlTiN coating on stainless steel SS 316L samples. The electrochemical behavior of the coating and the substrate was investigated using Electrochemical Impedance Spectroscopy (EIS) technique. Ringer Lectate solution was used as a simulated body fluid at 35 ± 2oC. The coating and substrate were characterized by Scanning Electron Microscopy (SEM) with Energy Dispersive X-ray Spectroscopy (EDX) and Surface Profilometry. The Scanning Electron Microscopy with Energy Dispersive X-ray Spectroscopy analysis revealed a consistent coating as a whole. The surface profilometry showed lower surface roughness after the coating. The Electrochemical Impedance Spectroscopy tests indicated that corrosion resistance of the coated sample was better, than the uncoated substrate in the electrolyte solution for short duration (one day) and behaved like cathodically protected coating and showed more resistivity. However, the Electrochemical Impedance Spectroscopy results varied because of the penetration of chlorite ions through the porosity in th coating and reaction with the coating material after the prolonged insertion.
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Bernard, L., G. Chertier, and R. Sauleau. "Wideband Circularly Polarized Patch Antennas on Reactive Impedance Substrates." IEEE Antennas and Wireless Propagation Letters 10 (2011): 1015–18. http://dx.doi.org/10.1109/lawp.2011.2168803.
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Chen, Si Si, Hong Lei, and Ru Ling Chen. "Effect of pH on Hard Disk Substrate Polishing in Glycine-Hydrogen Peroxide System Abrasive-Free Slurry." Key Engineering Materials 562-565 (July 2013): 691–96. http://dx.doi.org/10.4028/www.scientific.net/kem.562-565.691.
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The effect of pH on the material removal rate (MRR) and surface roughness (Ra) of hard disk substrate in glycine–hydrogen peroxide system abrasive-free slurry was investigated. The results show that, the MRR of hard disk substrate increases when both glycine and H2O2 are used in acidic slurries (pH=3.0) and decreases drastically in alkaline slurries (pH=10.0). The Ra of hard disk substrates is small in acidic slurries and increases drastically in alkaline slurries. Further, the effects of glycine, H2O2, and solution pH on hard disk removal were investigated by auger electron spectroscopy (AES), electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization measurements. We also develop a reaction scheme describing the surface chemistry of the hard disk in this system.
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Kotlarski, G., N. Ivanov, D. Dechev, S. Valkov, V. Mateev, and I. Marinova. "Structure and impedance of TiN coated 304L SS substrates." Journal of Physics: Conference Series 2710, no. 1 (2024): 012004. http://dx.doi.org/10.1088/1742-6596/2710/1/012004.
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Abstract In the present work, the effect of the deposition time on the structure and electrical impedance of reactive DC magnetron sputtered TiN coatings was studied. The structure of the coatings and the substrates was studied using X-ray diffraction (XRD). The electrical impedance and high frequency stability of the specimens was experimentally measured and the results were indicative of whether the application of the coatings as protective layers between the electrical contact pads of electrical contact systems is feasible.
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Zhang, Xiu Zhi, and Yuan Long Du. "Effects of Immersion Time on the Electrochemical Impedance Spectroscopy Model of Epoxy Coating Modified by Nano-Sized Titanium." Advanced Materials Research 139-141 (October 2010): 43–46. http://dx.doi.org/10.4028/www.scientific.net/amr.139-141.43.
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In this paper, the effects of immersion time on the electrochemical impedance spectroscopy model of nano-sized titanium modified epoxy coating immersed in 3.5(wt.%) sodilum chloride solution has been studied using electrochemical impedance spectroscopy(EIS). Through the analysis of the spectra of the coating at different immersion times, the results showed that the spectrum was different at the different immersion times. Therefore, the equivalent electrical circuit was varied with the increasing immersion time and there were the characteristics of the powder in the equivalent electrical circuits (electrochemical impedance spectroscopy model). By the study on the evlolution of impedance model in the given system, it was found that the nano-sized powder played an important part during the electrolyte diffusing to the surface of the substrate and the electrolyte reacting with the substrate
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Pan, Tung-Ming, Ching-Yi Chen, Tung-Yu Wu, and See-Tong Pang. "Impact of postdeposition annealing on the sensing and impedance characteristics of TbYxOy electrolyte–insulator–semiconductor pH sensors." RSC Advances 6, no. 80 (2016): 76673–78. http://dx.doi.org/10.1039/c6ra11377j.
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In this investigation, we explored the impact of postdeposition annealing (PDA) on the sensing and impedance characteristics of TbY<sub>x</sub>O<sub>y</sub> sensing films deposited on Si(100) substrates through reactive cosputtering for electrolyte–insulator–semiconductor (EIS) pH sensors.
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Chi, Panwang, Yesu Li, Hongfa Pan, et al. "Effect of Ni(P) Layer Thickness on Interface Reaction and Reliability of Ultrathin ENEPIG Surface Finish." Materials 14, no. 24 (2021): 7874. http://dx.doi.org/10.3390/ma14247874.
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Electroless Ni(P)/electroless Pd/immersion Au (ENEPIG) is a common surface finish in electronic packaging, while the Ni(P) layer increases the impedance of solder joints and leads to signal quality degradation in high-frequency circuits. Reducing the thickness of the Ni(P) layer can balance the high impedance and weldability. In this paper, the interfacial reaction process between ultrathin ENEPIG substrates with different Ni layer thicknesses (0.112 and 0.185 μm) and Sn–3.0Ag–0.5Cu (SAC305) solder during reflow and aging was studied. The bonding ability and reliability of solder joints with different surface finishes were evaluated based on solder ball shear test, drop test and temperature cycle test (TCT), and the failure mechanism was analyzed from the perspective of intermetallic compound (IMC) interface growth. The results showed that the Ni–Sn–P layer generated by ultrathin ENEPIG can inhibit the growth of brittle IMC so that the solder joints maintain high shear strength. Ultrathin ENEPIG with a Ni layer thickness of 0.185 μm had no failure cracks under thermal cycling and drop impact, which can meet actual reliability standards. Therefore, ultrathin ENEPIG has broad prospects and important significance in the field of high-frequency chip substrate design and manufacturing.
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Ferancova, Adriana, Maarit Hattuniemi, Satu Pääkkönen, et al. "Electrochemical Impedance Spectroscopy for Monitoring of Alkaline Phosphatase Reaction with Substrate." Procedia Technology 27 (2017): 315–16. http://dx.doi.org/10.1016/j.protcy.2017.04.129.
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Frewin, Christopher, Mohamad Beygi, Evans Bernardin, et al. "The Development of Monolithic Silicon Carbide Intracortical Neural Interfaces for Long-Term Human Implantation." Materials Science Forum 1062 (May 31, 2022): 195–203. http://dx.doi.org/10.4028/p-a08hju.
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Silicon Carbide (SiC) has been demonstrated as both a bio- and neuro-compatible wide-band-gap semiconductor with a high thermal conductivity and magnetic susceptibility and may be potentially compatible with human brain tissue. Two single-crystal, solid-state forms of SiC have been used to create monolithic intracortical neural implants (INI) without using physiologically exposed metals or polymers, thus eliminating many known reliability challenges in-vivo through a single, homogenous material. Amorphous SiC (a-SiC) was used to insulate 16-channel functional INI and the electrochemical and MRI compatibility (7T) performance were measured. 4H-SiC interfaces were fabricated using homoepitaxy,alternating epitaxial films of n-type and p-type forming an isolating PN junction which prevents substrate leakage current between the 16 adjacent electrodes and traces fabricated which were formed using deep-reactive ion etching (DRIE). 3C-SiC interfaces were fabricated in a similar fashion, but the epitaial conductive layers were grown on on both bulk crystalline (100) silicon and SOI wafers. In both cases a conformal coating of a-SiC was used as the top-side insulator and windows opened using RIE to allow electrochemical interaction. Electrochemical charaterization achieved through electrochemcial impedance spectroscopy (EIS) and cyclic voltammetry (CV) indicates performance on par, or exceeding, that of Pt reference electrodes with the same form fit. While magnetic resonance imaging (MRI) is an essential, non-contact method used to investigate issues with the nervous system, the high field MRI (e.g., 3 T and higher) necessary for proper diagnosis can be a safety issue for patients with INI due to inductive coupling between the powerful electromagnetic fields and the implanted device. This results in having to use lower electromagnetic field power (less than 1.5T), and therefore lower resolution, which hinders diagnostic prognosis for these patients. In this work the MRI compliance of epitaxial, monolithic SiC INI was studied. The specific absorption rate (SAR), induced heating, and image artifacts caused by the portion of the implant within a brain tissue phantom located in a 7 T small animal MRI machine were estimated and measured via finite element method (FEM) and Fourier-based simulations. Both the simulation and experimental results revealed that free-standing 3C-SiC films had no observable image artifacts compared to silicon and platinum reference materials inside the MRI at 7 T while FEM simulations predicted an ~30% SAR reduction for 3C-SiC compared to Pt. These initial simulations and experiments indicate a SiC monolithic INI may effectively reduce MRI induced heating and image artifacts in high field MRI.
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Wang, Lei, Cheng Qiang An, Jie Sun, Hai Yun Yu, and Chang Sheng Liu. "Adhesion Mechanism Analysis of Prepainted Steel Sheet at UV Ageing Test." Advanced Materials Research 415-417 (December 2011): 1470–73. http://dx.doi.org/10.4028/www.scientific.net/amr.415-417.1470.
Full textAbstract:
The aim of this study is to analyse the adhesion mechanism of prepainted steel sheet at UV ageing to simulate nature environment by means of T-bend, FTIR, SEM, EIS. After 2000 hours of ageing in the UV chamber we observed the adhesion decline of prepainted steel sheet by the T-bend test. Taking into account the characteristic peak position and intensity of FTIR spectroscopy was Hardly any change during the ageing period, there is no chemistry reaction on the organic coatings. However, After 2000 hours ageing the electrochemical impedance spectroscopy (EIS) of the prepainted steel sheet showed lower impedance. SEM result indicated that larger defects were found on the coating surface, which it is easy that the outside corrosive substances to meet metal substrate. In this way, the corrosive medium accelerated corrosion electrochemical reaction on the metal. growing corrosion products diffused between the metal substrate and the organic coating to destroy their binding. At last, the increscent corrosive area on metal interface caused the adhesion decline.