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171.
本文研究非线性电阻性网络多值问题的求解理论,文中给出了一系列重要的定理及其证明,这些定理是构思种新算法的理论基础。 相似文献
172.
润滑剂是脂肪酸酯,具有内外润滑作用。文中叙述了润滑剂的合成及性能测试。通过实验选定了反应催化剂——磷酸三丁酯,并确定了脂肪酸和醇合适的摩尔比 相似文献
173.
A uniform wire segmentation algorithm for performance optimization of distributed RLC interconnects was proposed in this paper. The optimal wire length for identical segments and buffer size for buffer inser-tion are obtained through computation and derivation, based on a 2-pole approximatian model of distribut-ed RLC interconnect. For typical inductance value and long wires under 180nm technology, experiments show that the uniform wire segmentation technique proposed in the paper can reduce delay by about 27%~56%, while requires 34%~69% less total buffer usage and thus 29% to 58% less power consump-tion. It is suitable for long RLC interconnect performance optimization. 相似文献
174.
The choices of the parameterizations for each component in a microwave emission model have significant effects on the quality of brightness temperature (T b) simulation. How to reduce the uncertainty in the T b simulation is investigated by adopting a statistical post-processing procedure with the Bayesian model averaging (BMA) ensemble approach. The simulations by the community microwave emission model (CMEM) coupled with the community land model version 4.5 (CLM4.5) over mainland China are conducted by the 24 configurations from four vegetation opacity parameterizations (VOPs), three soil dielectric constant parameterizations (SDCPs), and two soil roughness parameterizations (SRPs). Compared with the simple arithmetical averaging (SAA) method, the BMA reconstructions have a higher spatial correlation coefficient (larger than 0.99) than the C-band satellite observations of the advanced microwave scanning radiometer on the Earth observing system (AMSR-E) at the vertical polarization. Moreover, the BMA product performs the best among the ensemble members for all vegetation classes, with a mean root-mean-square difference (RMSD) of 4K and a temporal correlation coefficient of 0.64. 相似文献
175.
Cascaded sigma-delta (MASH) modulators for higher order oversampled analog-to-dlgital conversionrely on precise matching of contributions from different quantizers to cancel lower order quantization noise from intermediate delta-sigma stages. This paper studies the effect of analog imperfections in the implementation, such as finite gain of the amplifiers and capacitor ratio mismatch, and presents an adaptive algorithm and implementation architectures for digital correction of such analog imperfections. Behavioral simulations on 1-1-1 oversampled converters demonstrate over 10dB improvements in signal-to-noise an dover 20 dB improvements in dynamic range performance. 相似文献
176.
Ma Ruijie Liu Tao Luo Zhenghui Guo Qing Xiao Yiqun Chen Yuzhong Li Xiaojun Luo Siwei Lu Xinhui Zhang Maojie Li Yongfang Yan He 《中国科学:化学(英文版)》2020,63(3):325-330
Power conversion efficiency(PCE) of single-junction polymer solar cells(PSCs) has made a remarkable breakthrough recently.Plenty of work was reported to achieve PCEs higher than 16% derived from the PM6:Y6 binary system.To further increase the PCEs of binary OSCs incorporating small molecular acceptor(SMA) Y6,we substituted PM6 with PM7 due to the deeper highest occupied molecular orbital(HOMO) of PM7.Consequently,the PM7:Y6 has achieved PCEs as high as 17.0% by the hotcast method,due to the improved open-circuit voltage(V_(OC)).Compared with PM6,the lower HOMO of PM7 increases the gap between E_(LUMO-donor) and E_(HOMO-acceptor),which is proportional to V_(OC).This research provides a high PCE for single-junction binary PSCs,which is meaningful for device fabrication related to PM7 and commercialization of PSCs. 相似文献
177.
LiNi1/3Co1/3Mn1/3O2 nanocrystallites were synthesized by a one-step hydrothermal method, and uniform second particles were formed by a subsequent calcination process. X-ray diffraction results indicate that the as-synthesized material can be indexed by α-NaFeO2 layered structure with R-3 m space group. The results of Rietveld refinements show the I 003/I 104 value of the material is 2.032, and the nanostructured material presents low cation mixing, small cell volume, and a consequent suppression of lattice strain. The rate performances of the as-synthesized material can be further improved by coating Al2O3. The discharging capacity of Al2O3-coated material reaches 154.4 mAh g?1, and the capacity retention maintains 80.3 % after 50 cycles at 5 C in the voltage range of 2.5 to 4.5 V, while those of the bare one is only 139.0 mAh g?1 and 71.6 %, respectively. The transmission electron microcopy observation shows no zigzag layer exists on the surface of particle after cycles for Al2O3-coated LiNi1/3Co1/3Mn1/3O2. Compared to bare LiNi1/3Co1/3Mn1/3O2, the de-intercalation potential difference before and after cycles of Al2O3-coated one is smaller. This indicates that Al2O3 coating can reduce the electrochemistry polarization in the electrode bulk. 相似文献
178.
In this article, a reduced mixed finite element (MFE) formulation based on proper orthogonal decomposition (POD) for the non-stationary conduction-convection problems is presented. Also the error estimates between the reduced MFE solutions based on POD and usual MFE solutions are derived. It is shown by numerical examples that the results of numerical computation are consistent with theoretical conclusions. Moreover, it is shown that the reduced MFE formulation based on POD is feasible and efficient in finding numerical solutions for the non-stationary conduction-convection problems. 相似文献
179.
Xueliang Li Wenxiang He Zhenghui Xiao Fangfang Peng Jiejie Chen 《Journal of Solid State Electrochemistry》2013,17(7):1991-2000
Various structures and morphologies of Li3V2(PO4)3 precursors are synthesized by a novel ionothermal method using three kinds of imidazolium-based ionic liquids as both reaction mediums and structure-directing agents at ambient pressure. Nanostructured Li3V2(PO4)3/C cathode materials can be successfully prepared by a subsequent short calcination process. The structures, morphologies, and electrochemical properties are characterized by X-ray diffractometry, thermogravimetry, scanning and transmission electron microscopy, charge–discharge test, cyclic voltammetry, and electrochemical impedance spectroscopy. It shows that three kinds of materials synthesized present different morphologies and particle sizes. The result can be due to imidazolium-based ionic liquids, which combined with different anions play important role in forming the size and morphology of Li3V2(PO4)3 material. These materials present excellent performance with high rate capacity and cycle stability. Especially, the Li3V2(PO4)3/C material prepared in 1-ethyl-3-methylimadozolium trifluoromethanesulfonate ([emim][OTf]) can deliver discharge capacities of 127.4, 118.9, 105.5, and 92.8 mAh?g?1 in the voltage range of 3.0–4.3 V at charge–discharge rate of 0.1, 1, 10, and 20 C after 50 cycles, respectively. The excellent rate performance can be attributed to the uniform nanostructure, which can make the lithium-ion diffusion and electron transfer more easily across the Li3V2(PO4)3/electrolyte interfaces. 相似文献
180.
以千米尺度的空间网格为基本测算单元, 通过构建合适的评价指标体系, 开展区域生态承载力与产业布局一致性评价。以上海市青浦区为案例的研究结果表明: 1) 该方法可以有效地识别区域生态承载力与产业压力空间分布状况, 能够对区域生态承载力与产业布局一致性展开评价; 2) 青浦区平均产业压力指数为0.51, 生态承载力指数为0.25, 全区生态承载力与产业布局一致性较高, 平均一致性指数为3.12。 相似文献