检索结果-南通市图书馆

Investigation of Ge-Si Atomic Interdiffusion in Ge Nano-dots Multilayer Structure by Double Crystal X-ray Diffraction

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2007年第3期23卷 301-303页

作者： wenhua shi Lei ZHAO Liping LUO Qiming WANG State Key Laboratory on Integrated Optoelectronics Institute of Semiconductors Chinese Academy of Sciences Beijing 100083 China

The fluctuations of the strained layer in a superlattice or quantum well can broaden the width of satellite peaks in double crystal X-ray diffraction （DCXRD） pattern. It is found that the width of the 0^th peak is directly proportional to the fluctuation of the strained layer if the other related facts are ignored. By this method, the Ge-Si atomic interdiffusion in Ge nano-dots and wetting layers has been investigated by DCXRD. It is found that thermal annealing can activate Ge-Si atomic interdiffusion and the interdiffusion in the nano-dots area is much stronger than that in the wetting layer area. Therefore the fluctuation of the Ge layer decreases and the distribution of Ge atoms becomes homogeneous in the horizontal Ge （GeSi actually） layer, which make the width of the 0^th peak narrow after annealing.

关键词： X-ray diffraction GeSi Nano-dots Annealing Island

Calculation on phase diagrams of polyetherimide/ N,N-dimethylacetamide/H2O-BuOH casting system and their relevance to membrane performances

在线全文

学校读者我要写书评

暂无评论

Frontiers of Chemical Science and Engineering 2014年第3期8卷 312-319页

作者： Ming TAN Gaohong HE Yan DAI Rujie WANG wenhua shi State Key Laboratory of Fine Chemicals R&D Center of Membrane Science and Technology School of Chemical Engineering Dalian University of Technology Dalian 116024 China Key Laboratory of Biobased Materials Qingdao Institute of Bioenergy and Bioprocess Technology Chinese Academy of Sciences Qingdao 266101 China

The ternary phase diagrams of polyetherimide （PEI）/N,N-dimethylacetamide （DMAc） with H2O and BuOH as non-solvent were simulated using solubility parameter and Flory-Huggins theory. The phase diagrams show that 5.5% H2O/BuOH system containing 5% BuOH and 0.5% H2O or 6.5% H2O/BuOH system containing 6.2% BuOH and 0.3% H2O is required to induce liquid- liquid demixing for 20 wt-% PEI/DMAc casting solution. Therefore, BuOH can enhance the phase separation of the PEI casting solution and hereby induce higher porosity of the membrane, and the diffusion of BuOH into the water coagulation bath causes larger pore size easily compared with DMAc. Our predictions that the membrane pure water flux first increases then decreases, and the rejection ratio of bovine serum albumin decreases with the increasing concentration of BuOH were validated by the experiments using the prepared membranes.

关键词： phase diagram solubility parameter interaction parameter ultrafiltration Flory-Huggins theory

Nano-Au-decorated hierarchical porous cobalt sulfide derived from ZIF-67 toward optimized oxygen evolution catalysis:Important roles of microstructures and electronic modulation

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Carbon Energy 2024年第5期6卷 1-14页

作者： Hongyu Gong Guanliang Sun wenhua shi Dongwei Li Xiangjun Zheng Huan shi Xiu Liang Ruizhi Yang Changzhou Yuan Department of New Energy Materials School of Environmental and Chemical EngineeringJiangsu University of Science and TechnologyZhenjiangJiangsuChina Advanced Materials Institute Qilu University of Technology(Shandong Academy of Sciences)JinanShandongChina Shandong Saikesaisi Hydrogen Energy Co. Ltd.JinanShandongChina Department of Materials Science and Engineering School of Materials Science&EngineeringUniversity of JinanJinanShandongChina Department of New Energy Science and Engineering College of EnergySoochow Institute for Energy and Materials InnovationsSoochow UniversitySuzhouJiangsuChina

Enhancing both the number of active sites available and the intrinsic activity of Co-based electrocatalysts simultaneously is a desirable ***,a ZIF-67-derived hierarchical porous cobalt sulfide decorated by Au nanoparticles(NPs)(denoted as HP-Au@CoxSy@ZIF-67)hybrid is synthesized by low-temperature sulfuration *** well-defined macroporous-mesoporous-microporous structure is obtained based on the combination of polystyrene spheres,as-formed CoxSy nanosheets,and ZIF-67 *** novel three-dimensional hierarchical structure significantly enlarges the three-phase interfaces,accelerating the mass transfer and exposing the active centers for oxygen evolution *** electronic structure of Co is modulated by Au through charge transfer,and a series of experiments,together with theoretical analysis,is performed to ascertain the electronic modulation of Co by ***,HP-Au@CoxSy@ZIF-67 catalysts with different amounts of Au were synthesized,wherein Au and NaBH4 reductant result in an interesting“competition effect”to regulate the relative ratio of Co^(2+)/Co^(3+),and moderate Au assists the electrochemical performance to reach the highest ***,the optimized HP-Au@CoxSy@ZIF-67 exhibits a low overpotential of 340 mV at 10 mA cm^(-2)and a Tafel slope of 42 mV dec-1 for OER in 0.1 M aqueous KOH,enabling efficient water splitting and Zn-air battery *** work here highlights the pivotal roles of both microstructural and electronic modulation in enhancing electrocatalytic activity and presents a feasible strategy for designing and optimizing advanced electrocatalysts.

关键词： Au nanoparticles cobalt sulfide electronic modulation hierarchical porous structure oxygen evolution reaction

Time-frequency mask estimation-based speech enhancement using deep encoder-decoder neural network

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Journal of Acoustics 2021年第1期40卷 141-154页

作者： shi wenhua ZHANG Xiongwei ZOU Xia SUN Meng LI Li REN Zhengbing Army Engineering University Nanjing 210007 Beijing Aeronautical Technology Research Center Nanjing 210028 First Military Representation Office of Air Force Equipment Department Changsha 410114

A time-frequency mask estimation using deep encoder-decoder neural network for speech enhancement is *** mask estimation is learned implicitly by the deep encoder-decoder neural network *** with the time-frequency representation of the noisy speech to learn the nonlinear mapping function between the noisy and target *** deep encoder-decoder neural network employs convolution and de-nonvolution *** convolution encoder makes use of the local perception characteristic of convolution network to model the typical structural features of noisy speech in the time-frequency *** features are extracted and the influence of background noise is *** the decoder end,the speech signal is reconstructed from the extracted speech features in the encoder end and the local details are recovered layer by ***,skip connections are introduced between homologous layers to circumvent the low level details losing problem induced by pooling and down-sampling *** are conducted on the TIMIT dataset and the results demonstrate that the proposed method can effectively suppress noise and recover the detailed information of speech.

关键词： decoder network neural

Extension of Switching Costs Antecedents Based on Customers＇ Social Ties

在线全文

学校读者我要写书评

暂无评论

China Communications 2014年第1期11卷 152-163页

作者： shi wenhua JI Chen LI Xiaowen TANG Lingshu LV Tingjie School of Economics and Management Beijing University of Posts and Telecommunications Beijing 100876 China China Mobile Communications Corporation Beijing 100032 China

The effects of customers' social ties on switching costs have recently attracted researchers' *** study formally included customers' social ties as a new antecedent to supplement those elucidated by Burnham in *** empirical research,this study successfully verified the reliability and validity of items created to measure social ties,and it demonstrated the facilitating effects of social ties as an antecedent on customers' procedural and relational switching ***,the study lists managerial implications aimed at retaining customers through knowledge of this added antecedent.

关键词： Switching costs antecedent social ties

Exploring Enterprise Performance Indicators Network： A Case Study of China Telecommunication Industry

在线全文

学校读者我要写书评

暂无评论

China Communications 2012年第12期9卷 153-163页

作者： shi wenhua Du Yu Zhang Xiaohang School of Economics and Management Beijing University of Posts and Telecommunications Beijing 100876 P. R. China

Perforrmnce indicators play some important roles in enterprise operation. Both researchers and managers have recently pointed out that the identification of correlation between different performmance indicators may lead to a better understanding of business. However, it is becoming more and more difficult to measure and analyze these indicators since the fast growing number of performance indicators and the complex relationships between them The existing categories failed to reflect these changes in an adequate way, and the quantitative analysis methods for identifying the characters of those pefformance indicators are still worthy of investigation. The main objective of this paper is to propose a practical methodology for managing and analyzing performance indicators in enterprises, which focuses on building up a performance indicator system and discovering the characters of those performance indicators by applying complex network methods. The empirical results of a telecommunieation enterprise show that the proposed method can be effective in understanding the correlations between performance indicators.

关键词： performance indicator complex networks telecommunication industry

在线全文

学校读者我要写书评

暂无评论

不完全信息竞价模型在无线电频谱配置的应用

哈尔滨工业大学学报 2014年第5期46卷 125-128页

作者：刘纬华石文华东北大学工商管理学院沈阳110819 北京邮电大学经济管理学院北京100876

为探索资源产权制度和有偿使用制度的实现机制,以无线电频谱为例,依据一阶密封拍卖原理,通过建立运营商在无线电频谱拍卖过程中的不完全信息竞价模型,分析运营商的投标数量、竞价成功概率等因素对于运营商最优报价的影响以及中标者数量... 详细信息

为探索资源产权制度和有偿使用制度的实现机制,以无线电频谱为例,依据一阶密封拍卖原理,通过建立运营商在无线电频谱拍卖过程中的不完全信息竞价模型,分析运营商的投标数量、竞价成功概率等因素对于运营商最优报价的影响以及中标者数量对运营商期望利润函数的影响,并求解模型得出运营商报价的一般表达式.分析表明,将拍卖机制运用于无线电频谱资源分配,既充分体现频谱资源的经济价值,又有利于频谱资源的有效配置,同时是在运营商利润最大化前提下的优化决策.

关键词：资源配置频谱拍卖不完全信息

5省区2008年新课标生物学科高考模式及试卷的比较分析

在线全文

学校读者我要写书评

暂无评论

生物学通报 2009年第2期44卷 40-43页

作者：施问华江苏省滨海中学江苏滨海224500

广东、江苏等5个省区是全国实施高中新课程较早的地区。以这些省区的2008年高考为例,既比较分析了高考方案中生物学科的考查设置模式,又从高考试卷与新课程改革目标理念的相关性、反映新课程高考的创新性、与新课标不同版本教材的协同... 详细信息

广东、江苏等5个省区是全国实施高中新课程较早的地区。以这些省区的2008年高考为例,既比较分析了高考方案中生物学科的考查设置模式,又从高考试卷与新课程改革目标理念的相关性、反映新课程高考的创新性、与新课标不同版本教材的协同性、与以往高考的过渡性,以及课程标准内容在试卷中的分值和权重等方面,总结、归纳了生物学科高考试卷是如何与新课程改革进行对接的,获得了很多有益的启示。

关键词：新课程高考模式生物学科试卷分析

改进的尺度不变特征变换算法并行加速双目测距系统及其实现

在线全文

学校读者我要写书评

暂无评论

激光与光电子学进展 2019年第14期56卷 193-202页

作者：张志强施文华郑州商学院通识教育中心河南巩义451200 Department of Electrical and Computer Engineering Technical University of MunichMunich 80809Germany

在数字图像处理领域中,尺度不变特征变换(SIFT)算法是特征点识别的代表性算法。以开放运算语言(OpenCL)并行计算为加速手段,建立了基于改进的SIFT算法的双目测距系统,深入研究了如何加快SIFT算法的运算速度。在加快SIFT算法方面,选取了... 详细信息

在数字图像处理领域中,尺度不变特征变换(SIFT)算法是特征点识别的代表性算法。以开放运算语言(OpenCL)并行计算为加速手段,建立了基于改进的SIFT算法的双目测距系统,深入研究了如何加快SIFT算法的运算速度。在加快SIFT算法方面,选取了积分均值模糊,并利用OpenCL对其进行并行加速,对算法进行并行优化后,使之能够在NVIDIA GPU硬件平台上进行实现。在获取精确视差方面,对原SIFT匹配方法进行了改进,极大地提高了匹配效率。此外,构建了双目测距异构计算实验平台,并进行实验。实验平台对采集的图像进行了实时处理,验证了基于SIFT算法的并行加速计算的可行性,同时可以直观地看到中间计算过程和测距的结果。实验结果表明,本文方法与已有的加速优化工作相比,计算时间消耗比原方案要少得多。

关键词：机器视觉双目测距尺度不变特征变换算法开放运算语言并行加速