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[IEEE 2018 9th International Conference on Ultrawideband and Ultrashort Impulse Signals (UWBUSIS) - Odessa, Ukraine (2018.9.4-2018.9.7)] 2018 9th International Conference on Ultrawideband and Ultrashort Impulse Signals (UWBUSIS) - Monte Carlo Modeling of the Diodes with Lateral Resonant Tunneling Border
摘要： Diodes with resonant tunneling border (RTB) are studied as possible high speed and wide-band devices. The diodes represent planar two-terminal n+-n-n+-GaAs-based structures containing lateral active border as a AlGaAs/GaAs double barrier resonant tunneling structure connected to anode contact. The 2-D model of electron transport in the device is proposed. The analysis of the diodes operation was performed using ensemble Monte Carlo technique. Transfer matrix approach for simulation of tunneling transfer is applied. The influence of parameters of the diode structure such as a position of RTB, a composition of AlGaAs barriers and a material doping on current – voltage characteristics of diode has been investigated. strong influence of contact size and geometry on the diode characteristic. The aim of the work is to construct an effective numerical 2D model used to consider electron transport at high frequencies with taking into account hot-carrier effects in cases where the mean free path is comparable to the device dimensions and electron tunneling processes are in place. The basis of the proposed model is ensemble Monte Carlo method [4]. The other model elements are chosen by obtaining accurate physical results per reasonable time.
关键词： negative voltage current differential resistance,characteristics,heterojunction,quantum well,resonant tunneling border
更新于2025-09-23 15:21:21
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Analysis of the Mo/Mo Nanocrystalline Optical Coating Obtained with the Aid of Simultaneous Deposition and Ion Sputtering
摘要： Structure, optical properties, and resistance to sputtering are studied for a reflecting Mo-coating that is fabricated using magnetron deposition with simultaneous low-energy ion sputtering at the deposition rate that is higher than the etching rate. A Mo-polycrystalline mirror is used as a substrate. It is shown that the coating exhibits textured nanocrystalline structure with a relatively low spread of crystallite sizes and high resistance to sputtering. It is also demonstrated that the spectral reflection coefficient of such a Mo-coating differs from the spectral reflection coefficient of polycrystalline and single-crystalline Mo and the difference results from the effect of the structure of coating on its optical properties. A theoretical model of the coating formation is proposed.
关键词： optical properties,Mo-coating,nanocrystalline structure,ion sputtering,magnetron deposition,resistance to sputtering
更新于2025-09-23 15:21:21
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Comparison of the Physicochemical Properties of TiO2 Thin Films Obtained by Magnetron Sputtering with Continuous and Pulsed Gas Flow
摘要： In this paper, a comparison of TiO2 thin ?lms prepared by magnetron sputtering with a continuous and pulsed gas ?ow was presented. Structural, surface, optical, and mechanical properties of deposited titanium dioxide coatings were analyzed with the use of a wide range of measurement techniques. It was found that thin ?lms deposited with a gas impulse had a nanocrystalline rutile structure instead of ?brous-like anatase obtained with a continuous gas ?ow. TiO2 thin ?lms deposited with both techniques were transparent in the visible wavelength range, however, a much higher refractive index and packing density were observed for coatings deposited by the pulsed gas technique. The application of a gas impulse improved the hardness and scratch resistance of the prepared TiO2 thin ?lms.
关键词： optical properties,scratch resistance,thin ?lms,gas impulse magnetron sputtering,microstructure,hardness,surface properties,mechanical properties,TiO2
更新于2025-09-23 15:21:21
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Optimization of synthesis condition of water-resistant and thin titanium oxide layer-coated Ni-rich layered cathode materials and their cathode performance
摘要： In this study, in order to develop water-resistant LiNiaCobAl1?a?bO2 (a > 0.85, NCA) cathode materials which exhibit high-rate performance, the surface coating of NCA with titanium oxide (TiOx) was examined. The synthesis conditions for the TiOx-coated NCA cathode materials were investigated, by taking into account some essential factors in the surface coating of NCA by TiOx, with a view to improving the rate performance. We successfully prepared the TiOx-coated NCA cathode material, the rate performance of which is superior to that of the conventionally prepared NCA cathode materials, typically using a polyvinylidene difluoride (PVdF) binder and N-methyl-2-pyrrolidone (NMP) solvent. Their surface analysis suggested that the specific surface structure of TiOx layer coated on the NCA particle leads to both a water-resistant property and a high permeability of Li+ ions through it in the charging/discharging process.
关键词： Lithium ion secondary battery,Water-based hybrid polymer binder,TiOx coating layer,Water resistance,Ni-rich lithium transition metal oxide
更新于2025-09-23 15:21:21
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[IEEE 2019 International Conference on Communication and Electronics Systems (ICCES) - Coimbatore, India (2019.7.17-2019.7.19)] 2019 International Conference on Communication and Electronics Systems (ICCES) - Implementation On High-Performance Quasi-Z-Source Series Resonant DC To DC Converter for Photovoltaic Module Level Power Electronics Applications
摘要： For every simple connected graph, we present a polynomial time algorithm for computing a numerical index, which is composed of primary and secondary parts. Given a graph G = (V , E) where V and E are, respectively, vertex and edge sets, the primary part of the index is a set of |V | fractions and the secondary part of the index is a set of |B| × |V | fractions, where B is the partition of the vertex set V . Basically, each fraction in the primary and secondary parts is the electrical resistance between two vertices when every edge in the graph is replaced with a unit resistor (1 (cid:127)). The experimental results show that our indexing algorithm produced a unique index for every simple connected graph with ≤10 vertices, including all graphs that are counterexamples for detecting graph isomorphism by resistance spectrum comparison. The strength of our indexing algorithm lies in its extreme simplicity. An index of a graph is solely derived from the determinants of reduced Laplacian matrices, which represent the graph. Therefore, the performance of our indexing algorithm only depends on how fast the matrix determinants can be computed.
关键词： graph indexing,resistance distance,Electrical resistance,simple connected graphs,graph isomorphism
更新于2025-09-23 15:21:01
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Contents: (Adv. Funct. Mater. 44/2018)
摘要： Silica nanofibrous membranes produced by direct electrospinning of a sol-gel solution without a sacrificing polymer allow high-end separation and purification due to a high thermal and chemical resistance. The water repellent or absorbing nature can be tuned by applying a humidity or thermal treatment. It is showcased that fast gravity driven membrane separation of heterogeneous azeotropes can be achieved.
关键词： thermal resistance,chemical resistance,sol-gel,electrospinning,azeotrope separation,silica nanofibrous membranes
更新于2025-09-23 15:21:01
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LTspice Electro-Thermal Model of Joule Heating in High Density Polyethylene Optical Fiber Microducts
摘要： At present, optical fiber microducts are joined together by mechanical type joints. Mechanical joints are bulky, require more space in multiple duct installations, and have poor water sealing capability. Optical fiber microducts are made of high-density polyethylene which is considered best for welding by remelting. Mechanical joints can be replaced with welded joints if the outer surface layer of the optical fiber microduct is remelted within one second and without thermal damage to the inner surface of the optical fiber duct. To fulfill these requirements, an electro-thermal model of Joule heat generation using a copper coil and heat propagation inside different layers of optical fiber microducts was developed and validated. The electro-thermal model is based on electro-thermal analogy that uses the electrical equivalent to thermal parameters. Depending upon the geometric shape and material properties of the high-density polyethylene, low-density polyethylene, and copper coil, the thermal resistance and thermal capacitance values were calculated and connected to the Cauer RC-ladder configuration. The power input to Joule heating coil and thermal convection resistance to surrounding air were also calculated and modelled. The calculated thermal model was then simulated in LTspice, and real measurements with 50 μm K-type thermocouples were conducted to check the validity of the model. Due to the non-linear transient thermal behavior of polyethylene and variations in the convection resistance values, the calculated thermal model was then optimized for best curve fitting. Optimizations were conducted for convection resistance and the power input model only. The calculated thermal parameters of the polyethylene layers were kept intact to preserve the thermal model to physical structure relationship. Simulation of the optimized electro-thermal model and actual measurements showed to be in good agreement.
关键词： thermal capacitance,RC-ladder,electro-thermal model,thermal resistance,Cauer network,high-density polyethylene,Foster network
更新于2025-09-23 15:21:01
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Effect of laser shock processing on oxidation resistance of laser additive manufactured Ti6Al4V titanium alloy
摘要： The high-temperature oxidation resistance of laser additive manufactured (LAM) Ti6Al4V before and after laser shock processing (LSP) was investigated. The samples were oxidized at 400?800 °C for 1?50 h in air. The results revealed that the rate of weight gain of the Ti6Al4V fabricated through LAM decreased, and LSP had a positive effect on increasing the oxidation resistance. At an oxidation temperature of 700 °C, an aluminum-rich layer was observed in the cross-section before LSP. After LSP, the aluminum-rich layer changed to three layers. The aluminum-rich layer prevented the diffusion of oxygen, which improved the oxidation resistance of the Ti6Al4V.
关键词： Ti6Al4V titanium alloy,High-temperature oxidation resistance,Laser shock processing,Laser additive manufacturing
更新于2025-09-23 15:21:01
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Manufacturing profile-free copper foil using laser shock flattening
摘要： Copper foil is a key material of printed circuit boards and plays an important role in the conductance of electric circuits and interconnection of electronic components. When high-frequency signals were transmitted in rough copper foil wires, the conductor resistance, wire loss, and signal loss increased because of the skin effect. To reduce the negative influence of the skin effect and improve the quality of the copper foil, a laser shock flattening (LSF) method was proposed to manufacture profile-free copper foil with high performance. It was concluded that the better flattening effect for large-area profile-free copper foil could be achieved at a pulse energy of 0.25 J and an overlap rate of 25%, and its surface roughness decreased by 67.0% from 52.1 nm to 17.2 nm. Subsequently, to determine the mechanism for the flattened deformation of copper foil induced by LSF, the microstructures of the copper foil before and after flattening were characterised using transmission electron microscopy. A higher dislocation density and a few deformation twins were found in the profile-free copper foil. Ultimately, nano-indentation, micro-tensile, and electrochemical corrosion tests indicated that the mechanical properties and corrosion resistance of the copper foil were significantly improved by LSF. This technique would enable the successful fabrication of large-area profile-free copper foil with high performance for the emerging applications of ultra-high-frequency signal communication and printed circuit board manufacture.
关键词： Corrosion resistance,Mechanical properties,Flattened deformation mechanism,Microstructures,Laser shock flattening,Profile-free copper foil
更新于2025-09-23 15:21:01
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Mobile Teaching and Learning of Coupled-Line Structures: The multiple-1D coupled-line finite-difference time-domain method.
摘要： Fever is one of the most common symptoms of illness in infants and represents a clinical challenge due to the potential for serious bacterial infection. As delayed treatment for these infections has been correlated with increased morbidity and mortality, broad-spectrum β-lactam antibiotics are often prescribed while waiting for microbiological lab results (1–3 days). However, the spread of antibiotic resistance via the β-lactamase enzyme, which can destroy β-lactam antibiotics, has confounded this paradigm; empiric antibiotic regimens are increasingly unable to cover all potential bacterial pathogens, leaving some infants effectively untreated until the pathogen is characterized. This can lead to lifelong sequela or death. Here, we introduce a fluorescent, microfluidic assay that can characterize β-lactamase derived antibiotic susceptibility in 20 min with a sensitivity suitable for direct human specimens. The protocol is extensible, and the antibiotic spectrum investigated can be feasibly adapted for the pathogens of regional relevance. This new assay fills an important need by providing the clinician with hitherto unavailable point of care information for treatment guidance in an inexpensive and simple diagnostic format.
关键词： beta-lactamase,Antibiotic resistance,point of care,microfluidic
更新于2025-09-23 15:21:01