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排序方式: 共有153条查询结果,搜索用时 15 毫秒
1.
Design aspects of MOS-controlled thyristor elements: technology,simulation, and experimental results
Bauer F. Halder E. Hofmann K. Haddon H. Roggwiller P. Stockmeier T. Burgler J. Fichtner W. Muller S. Westermann M. Moret J.-M. Vuilleumier R. 《Electron Devices, IEEE Transactions on》1991,38(7):1605-1611
2.5-kV thyristor devices have been fabricated with integrated MOS controlled n+-emitter shorts and a bipolar turn-on gate using a p-channel DMOS technology. Square-cell geometries with pitch variations ranging from 15 to 30 μm were implemented in one- and two-dimensional arrays with up to 20000 units. The impact of the cell pitch on the turn-off performance and the on-state voltage was studied for arrays with constant cathode area as well as for single-cell structures. By realizing MOS components with submicrometer channel lengths, scaled single cells are shown to turn off with current densities of several kiloamperes per square centimeter at a gate bias of 5 V. In the case of multi-cell ensembles, turn-off performance is limited due to inhomogeneous current distribution. Critical process parameters as well as the device behavior were optimized through multidimensional numerical simulation 相似文献
2.
G. N. Lilis A. Halder S. Telukunta S. Servetto 《International journal for numerical methods in engineering》2007,71(3):277-312
Many problems in geophysics, acoustics, elasticity theory, cancer treatment, food process control and electrodynamics involve study of wave field synthesis (WFS) in some form or another. In the present work, modelling of wave propagation phenomena is studied as a static problem, using finite element method and treating time as an additional spatial dimension. In particular, WFS problems are analysed using discrete methods. It is shown that a fully finite element-based scheme is very natural and effective method for the solution of such problems. Distributed WFS in the context of two-dimensional problems is outlined and incorporation of any geometric or material non-linearities is shown to be straightforward. This has significant implications for problems in geophysics or biological media, where material inhomogeneities are quite prevalent. Numerical results are presented for several problems referring to media with material inhomogeneities and predefined absorption profiles. The method can be extended to three-dimensional problems involving anisotropic media properties in a relatively straightforward manner. Copyright © 2006 John Wiley & Sons, Ltd. 相似文献
3.
The combustion of single bituminous char particles (4-12 mm diameter) was studied in a turbulent fluidized bed operated at 1098 K using air as the fluidising medium. Results indicated that particles burn with constant density following a shrinking sphere model. Burning rates are much higher than those observed in a bubbling fluidized bed. The rate of transfer of oxygen to the particle surface is also higher than that observed in bubbling beds. A model is proposed to calculate the Sherwood numbers of the burning carbon particles. Experimental values of the Sherwood numbers agree well with those predicted from the model. 相似文献
4.
Spherical electrode carbon particles prepared from carbon rods of dry cell batteries have been used to study the attrition behaviour in a bubbling fluidized bed combustor. Experiments have been conducted in a 40 mm I.D. and 1 m high fluidized bed combustor operated at 1 m/s superficial velocity. The bed was operated with nitrogen and with two different oxygen concentrations at 850°C to study the effect of combustion on attrition of these particles. The experimental technique used allowed the time resolution of attrited fines generation, providing detailed curves of attrition rates as a function of time. Attrition rate constants have been evaluated. Results show an enhancement of attrition due to combustion even for spherical, homogeneous and smooth particles. 相似文献
5.
Satish Kumar Vemuri Satyajit Halder Rajkiran Reddy Banala Hari Krishnreddy Rachamalla Vijaya Madhuri Devraj Chandra Shekar Mallarpu Uttam Kumar Neerudu Ravikiran Bodlapati Sudip Mukherjee Subbaiah Goli Peda Venkata Gurava Reddy Annapareddy Venkata Malarvilli Thakkumalai Kuladip Jana 《International journal of molecular sciences》2022,23(4)
Background: Breast cancer is the most common cancer in women globally, and diagnosing it early and finding potential drug candidates against multi-drug resistant metastatic breast cancers provide the possibilities of better treatment and extending life. Methods: The current study aimed to evaluate the synergistic anti-metastatic activity of Curcumin (Cur) and Paclitaxel (Pacli) individually, the combination of Curcumin–Paclitaxel (CP), and also in conjugation with gold nanoparticles (AuNP–Curcumin (Au-C), AuNP–Paclitaxel (Au-P), and AuNP–Curcumin–Paclitaxel (Au-CP)) in various in vitro and in vivo models. Results: The results from combination treatments of CP and Au-CP demonstrated excellent synergistic cytotoxic effects in triple-negative breast cancer cell lines (MDA MB 231 and 4T1) in in vitro and in vivo mouse models. Detailed mechanistic studies were performed that reveal that the anti-cancer effects were associated with the downregulation of the expression of VEGF, CYCLIN-D1, and STAT-3 genes and upregulation of the apoptotic Caspase-9 gene. The group of mice that received CP combination therapy (with and without gold nanoparticles) showed a significant reduction in the size of tumor when compared to the Pacli alone treatment and control groups. Conclusions: Together, the results suggest that the delivery of gold conjugated Au-CP formulations may help in modulating the outcomes of chemotherapy. The present study is well supported with observations from cell-based assays, molecular and histopathological analyses. 相似文献
6.
Catalytic hydrogenation of o-nitroanisole in a microreactor: Reactor performance and kinetic studies
Sunitha Tadepalli Raghunath Halder Adeniyi Lawal 《Chemical engineering science》2007,62(10):2663-2678
Hydrogenation of o-nitroanisole to o-anisidine was conducted in a packed-bed microreactor as a model hydrogenation reaction of importance to the pharmaceutical and fine chemicals industries with the aim of investigating the reactor performance and kinetics of the reaction. The effects of different processing conditions viz. hydrogen pressure, o-nitroanisole concentration, temperature, and residence time on the conversion of o-nitroanisole, space-time yield (STY), and selectivity of o-anisidine were studied using 2% Pd/zeolite catalyst. The kinetic study was undertaken in a differential reactor mode keeping the conversion of o-nitroanisole at less than 10%. During the kinetic study, it was observed that the intermediate 2-methoxynitrosobenzene was present in the reactor at low catalyst loading and low conversions because of short residence time in the reactor. Therefore, for the kinetics study, the overall reaction was treated as comprising two separate reactions: first the reduction of o-nitroanisole to 2-methoxynitrosobenzene and then, the reduction of 2-methoxynitrosobenzene to o-anisidine. Internal and external mass and heat transfer limitations in the microreactor were examined. Different rate laws using different mechanisms from the literature were considered to fit the experimental data. Two rate equations for the two consecutive reactions assuming Langmuir-Hinshelwood mechanism provided the best fit to the experimental data. These two rate equations predicted the experimental rates within 10% error. Experiments were also carried out in an integral reactor, and the reactor performance data were found to be in agreement with the predictions of the theoretical models. 相似文献
7.
System-Level Specification Testing Of Wireless Transceivers 总被引:1,自引:0,他引:1
Halder A. Bhattacharya S. Chatterjee A. 《Very Large Scale Integration (VLSI) Systems, IEEE Transactions on》2008,16(3):263-276
This paper presents an efficient system-level manufacturing test methodology for wireless transceiver systems. Conventional system-level testing procedures incur large test times and require the use of multiple test hardware configurations for measuring frequency and modulation-domain performance specifications, e.g., system-gain, nonlinearity, noise-figure, channel power, adjacent-channel power-ratio, error vector magnitude, modulation signal-to-noise ratio and bit error rate. The proposed test methodology addresses these problems by simplifying the test stimulus application and test response capture/analysis procedures. In addition, the number of test hardware configurations needed to measure all the performance specifications is minimized and fewer as well as shorter tests are used to determine all the test specification values of interest. Test accuracy is achieved by optimizing the test stimulus so that the observed response has strong statistical correlation with the target test specification values. Experimental results show significant testing time reduction and was validated on 1.575 GHz and 900 MHz wireless transceiver prototypes. 相似文献
8.
AKT, is a serine/threonine protein kinase comprising three isoforms—namely: AKT1, AKT2 and AKT3, whose inhibitors have been recognized as promising therapeutic targets for various human disorders, especially cancer. In this work, we report a systematic evaluation of multi-target Quantitative Structure-Activity Relationship (mt-QSAR) models to probe AKT’ inhibitory activity, based on different feature selection algorithms and machine learning tools. The best predictive linear and non-linear mt-QSAR models were found by the genetic algorithm-based linear discriminant analysis (GA-LDA) and gradient boosting (Xgboost) techniques, respectively, using a dataset containing 5523 inhibitors of the AKT isoforms assayed under various experimental conditions. The linear model highlighted the key structural attributes responsible for higher inhibitory activity whereas the non-linear model displayed an overall accuracy higher than 90%. Both these predictive models, generated through internal and external validation methods, were then used for screening the Asinex kinase inhibitor library to identify the most potential virtual hits as pan-AKT inhibitors. The virtual hits identified were then filtered by stepwise analyses based on reverse pharmacophore-mapping based prediction. Finally, results of molecular dynamics simulations were used to estimate the theoretical binding affinity of the selected virtual hits towards the three isoforms of enzyme AKT. Our computational findings thus provide important guidelines to facilitate the discovery of novel AKT inhibitors. 相似文献
9.
Halder Sajal Lim Kwan Hui Chan Jeffrey Zhang Xiuzhen 《Knowledge and Information Systems》2022,64(4):963-993
Knowledge and Information Systems - Personalized itinerary recommendation has garnered wide research interests for their ubiquitous applications. Recommending personalized itineraries is complex... 相似文献
10.
Water transport in cellular tissues during thermal processing 总被引:1,自引:0,他引:1
Amit Halder Ashim K. Datta Roger M. Spanswick 《American Institute of Chemical Engineers》2011,57(9):2574-2588
Accurate modeling of water transport in food materials requires knowledge of how transport properties depend on the material structure. Water transport in a cellular tissue depends on its pathway (intracellular versus extracellular), which in turn depends on temperature. Using a combination of permeability measurement, pore‐size distribution analysis and bioimpedance analysis, it is shown that water in a cellular tissue (e.g., potatoes) is mostly intracellular at lower temperatures at which cell membranes are intact. During drying at high‐temperatures, cell membranes in potatoes are damaged, and the moisture transport pathway is primarily extracellular (through intercellular spaces and the lacunae created by the killed cells), with a much lower resistance to water transport. The difference in moisture diffusivity in potatoes for the two pathways has been estimated to be three orders of magnitude. Therefore, transport properties measured or predicted at low temperatures cannot be used for high temperatures because they correspond to different moisture migration pathways. © 2010 American Institute of Chemical Engineers AIChE J, 2011 相似文献