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This work presents a study on the quality factor (Q-factor) of the passively temperature compensated CMOS-MEMS resonators through the collected material/experimental database and finite-element (FEM) simulation. By adapting an anchor-loss-free double-ended tuning fork (DETF) resonator design, the intrinsic material loss is expected to be the major loss mechanism in CMOS-MEMS resonators that limits...
The threshold switching characteristics of amorphous NbOx thin films is investigated with particular emphasis on temperature dependence of the switching characteristics. Threshold switching in this material is believed to result from a thermally-induced insulator-metal-transition (IMT) induced along a filamentary path by local Joule heating. Increasing the operating temperature is shown to lead to...
The most important stress factors for electric machines insulation in the automotive environment can be summarized by the mnemonic expression TEAM (thermal, electrical, ambient, and mechanical stress). Even already each individual of the above mentioned stresses can be fatal for the electric machine insulation they generally act simultaneously making even worse deterioration process and so faster...
Self consistent first principle calculations on superconducting material WN in cubic phase (NaCl-type) have been performed to understand their fundamental characteristics of the structural, electronic and thermal properties. The bulk modulus (BO), Debye temperature (6D), density of states (N (EF)), electronic specific heat coefficient (γ) and electron-phonon coupling constant (λ) have been computed...
The method of the split cylinder resonator cavity (SCR) is used to characterize accurately and simultaneously in one temperature cycle, dimensional and electrical characteristics of the cavity and the electromagnetic properties of a dielectric material. To do this several modes are used, some to control the cavity and others to control the sample.
Audible noise of automotive alternators is a key point for future cars. Its reduction requires a multiphysic approach including electromagnetic, vibro-acoustic and thermal aspects. In this perspective, this paper investigates the influence of stator temperature on the acoustic noise of a claw-pole alternator. Experimental results show a clear reduction of sound power level and change in noise peak...
Electrode material seriously influences the characteristics of vacuum arc and further affects the performance of switches. In this paper, thermal processes of six kinds of metal anodes (including pure metal and alloy anodes) are simulated and researched. Two kinds of temperature calculation methods are used. Simulation results show that W and Mo anodes have the higher temperature than Cu, Cr, CuCr25...
Recent developments of third generation relaxor-PT piezoelectric type single crystals, Mn:PIN-PMN-PT, herald significant potential benefits to high power ultrasonic devices due to their high electro-mechanical coupling coefficient, low mechanical losses and increased temperature and electric field stability. This study reports on two power ultrasonic transducers, one based on piezocrystal and one...
Within the last years a constant increase of application temperatures for electronic packaging is observable, this is true for sensor applications, for power electronics packages and also for Smart Power Modules, integrating control logic and power ICs in one compact package. Drivers for HT use are on the one hand the introduction of GaN/SiC power electronic devices; these need modules to operate...
We investigated the mechanical properties of a silver sinter paste dependent on sintering and drying conditions. For these experiments we fabricated dedicated samples without silicon and leadframe to investigate the pure material properties. Our investigation on the influence of drying and sintering conditions demonstrated that the longer the sintering time and the higher the temperature the higher...
Batteries are a critical component that largely governs the performance and cost of an electric vehicle. There are a variety of types of batteries competing for use, each with cons and pros. Among these options, Li_4 Ti_5 O_12 batteries excel with superior performance in terms of safety, stability, service life. In order to make better use of its merits for electric vehicle applications, understanding...
Silver-based low temperature sintering technology (LTST) is becoming a promising alternative to bond or joint the large area joints as die attach for high temperature power modules. A review of the silver-sintered die attach technologies will be presented in this paper, as well as a roadmap of challenge of the state-of-the-art silver sintering. Then, highlighted are the methodology of sintering process,...
Polymer based organic photovoltaic systems, which can be mass-produced by roll-to-roll printing technology, hold the promise for a cost-effective, lightweight and mechanical flexible solar energy conversion platform. Nevertheless, challenges still remain for large-scale applications of these flexible solar cells. One of the issues of great importance is the long-time reliability of solar cell module...
Sn-3.5Ag nanosolder in tiny sizes can provide a practical way to solve the high soldering temperature problem of lead-free solder alloy in fine pitch interconnectivity owing to the unique nanosize effect and meantime stand a higher working temperature just as the bulk material after welding. In this paper, a simple approach to synthesis Sn-3.5Ag nanoparticles by chemical reduction at room temperature...
Measurements of physical transport properties of thermoelectric materials are plagued by large uncertainties (of tens of percent). Development of new materials towards larger efficiency in converting heat into electrical energy would benefit from improved measurement reliability. We are proposing to extend the 3ω method for the simultaneous measurement of the Seebeck coefficient, electrical conductivity...
A multi-physics model is developed based on P2D model, including the electrochemical part, thermal part and the temperature distribution. It can simulate the physical and chemical phenomena from the scale of the active particles to the scale of whole battery. The charging optimization is also investigated, two internal characteristics, which can only be calculated by the proposed model, are treated...
Lifetime of most vacuum and gas-discharge switching devices is determined primarily by electroerosion resistance of electrodes manufactured from refractory materials — molybdenum, tungsten, etc. Low thermal conductivity and electrical conductivity of these materials contribute to an undesirable increase of temperature of the electrodes surface. In this paper the calculation results of characteristics...
A methodology for designing energy reduction schemes of an existing MEE system is presented in this paper. These methods include a simulation model built in WinGEMS and an optimization scheme based on energy cascade utilization principles. A working MEE system at Fujian Nanping Paper co., LTD. in China was employed as a case study. The simulation results closely approach actual production data from...
In paragraph are presented the results of research based on the AC conductivity of the wet oil-impregnated insulating paper, depending on the moisture content and temperature of the samples. This is a new experimental method, which converts the results from the FDS to the reference temperature of 293.15 K (20 ° C). Takes account of the activation energy for conduction and relaxation time
Sn-3.5Ag nanosolder in tiny sizes can provide a practical way to solve the high soldering temperature problem of lead-free solder alloy in fine pitch interconnectivity owing to the unique nanosize effect and meantime stand a higher working temperature just as the bulk material after welding. In this paper, a simple approach to synthesis Sn-3.5Ag nanoparticles by chemical reduction at room temperature...
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