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Chalcogen-dependent catalytic properties of RuX2 (X = S/Se/Te) nanoparticles decorated carbon nanofibers for hydrogen evolution in acidic and alkaline media

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Nano Research 2024年第4期17卷 2528-2537页

作者： Chengkai He Yue Wei Jia Xu Yujie Wei Tao Wang Rongfei Liu Lvlv Ji Zhun Liu Sheng Wang School of Materials Science and Engineering Zhejiang Sci-Tech UniversityHangzhou 310018China department of Physics Shaoxing UniversityShaoxing 312000China Zhejiang Kangjiesi New Material technology Co. LTDZhuji 311800China

Transition metal dichalcogenides(TMDs),with the general formula MX_(2)(M=Mo/W/Fe/Co/Ni,etc.;X=S/Se/Te),have attracted extensive research interests for hydrogen evolution reaction(HER).Compared with numerous studies on noble-metal-free TMDs,the chalcogen-dependent HER catalytic properties of noble-metal-based TMDs are lack of sufficient research ***,a facile electrospinning-assisted synthetic strategy is proposed to synthesize ruthenium dichalcogenides(RuX_(2),X=S/Se/Te)nanoparticles decorated carbon nanofibers(CNFs).Benefiting from the identical nanofibrous morphology and exposed crystal planes of RuX_(2)(111),the catalytic activities of RuX_(2)@CNFs samples were investigated and compared in a fair and direct *** electrochemical measurements coupled with density functional theory calculations were carried out to probe their intrinsic HER catalytic activities,resulting in the catalytic activity order of RuS_(2)@CNFs>RuSe_(2)@CNFs>RuTe_(2)@CNFs in acidic media and that of RuS_(2)@CNFs>RuTe_(2)@CNFs>RuSe_(2)@CNFs in alkaline *** superior catalytic performance of RuS_(2)@CNFs mainly stems from the relative lower HER energy barriers and thereby the higher intrinsic catalytic activity of RuS_(2)(111),leading to ultralow overpotentials of 44 and 9 mV at 10 mA·cm^(-2) in acidic and alkaline media,***_(2)(111)is endowed with the more optimized Gibbs free energy of hydrogen adsorption(ΔGH*)than RuTe_(2)(111),but RuTe_(2)(111)shows enhanced catalytic property for H_(2)O dissociation and OH-desorption than RuSe_(2)(111),therefore,resulting in the altered catalytic activity sequences for RuSe_(2) and RuTe_(2) in acidic and alkaline media.

关键词： hydrogen evolution reaction transition metal dichalcogenides carbon nanofibers electrocatalysis catalytic activity

Large-scale P2PVOD system:Focusing on clients

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Science China(Information Sciences) 2011年第8期54卷 1677-1690页

作者： HUANG Yan 1,XU Ke 2,LI HaiTao 2 , CAO Yang 1 & YAO Xin 1 1 Shanghai SynaCast media tech Co.,Ltd,Shanghai 201204,China 2 department of Computer Science & technology,Tsinghua University,Beijing 100084,China Shanghai SynaCast media tech Co. Ltd. department of Computer Science & technology Tsinghua University

Using P2P network to provide video on demand (VOD) service can support large-scale users so as to save the bandwidth cost of *** VOD must support VCR characters (drag,pause,randomly choosing watching position,etc.),building a large-scale expansion of high-performance VOD system still faces huge *** paper first presents a P2P based reference model,defines the design object,and analyzes the *** then taking PPLive demand system as an example,it gives client-based solutions,including disk cache-out strategy,memory cache prefetch strategy,maintaining relations between neighbors,task scheduling,data upload strategies and so ***-demand systems are putting into practice at present with satisfactory fluency and drag *** largest number of simultaneous online users is over 210000,and online video data is over 700. Compared with traditional client-server model,the average bandwidth saving rate of servers is 88% or more,and the bandwidth saving rate of user-number's the peak value can be up to 93%.

关键词： P2P VOD server bandwidth saving rate fluency drag delay

Propagation of local spatial solitons in power-law nonlinear PT-symmetric potentials based on finite difference

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Communications in Theoretical Physics 2021年第12期73卷 14-24页

作者： Hao Ji Yinghong Xu Chaoqing Dai Lipu Zhang department of Mathematics Zhejiang Sci-Tech UniversityHangzhou310018China department of Physics Zhejiang A&F UniversityHangzhou311300China College of media Engineering Communication University of ZhejiangHangzhou310018China

We consider the(2+1)-dimensional nonlinear Schrodinger equation with power-law nonlinearity under the parity-time-symmetry potential by using the Crank-Nicolson alternating direction implicit difference scheme,which can also be used to solve general boundary problems under the premise of ensuring *** use linear Fourier analysis to verify the unconditional stability of the *** demonstrate the effectiveness of the scheme,we compare the numerical results with the exact soliton ***,by using the scheme,we test the stability of the solitons under the small environmental disturbances.

关键词： nonlinear Schrodinger equation localized spatial solitons PT-symmetric potential ADI difference scheme stability

Achieving greater anonymity in network latency

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通讯和计算机（中英文版） 2009年第12期6卷 38-46页

作者： Longy O. Anyanwu Jared Keengwe Gladys A. Arome Mathematics and Computer Science Fort Hays State University Hays Kansas 67601 USA department of Teaching and Learning University of North Dakota ND 58202 USA department of media and instructional tech Florida Atlantic University FL 33431 USA

Each Internet communication leaves trails that can be followed back to the user. Notably, anonymous communication schemes are purposed to hide users identity as to personal, source, destination location and content information. Notably, no network capability is in existence to completely negate anonymity leakage in network latency[1], thus, the minimization of anonymity leakage in network latency becomes critically salient. The purpose of this paper is to investigate network latency anonymity leaks, and propose practical techniques for their reduction. In this direction, the author investigate the following technical question: What implementation techniques can be configured to truly reduce anonymity leaks using deployable systems and exploiting the popular Tor security strategies.

关键词：匿名通信网络延迟 lnternet 实用技术内容信息目标位置网络能力网络延时

Saliency-Based Fidelity Adaptation Preprocessing for Video Coding

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Journal of Computer Science & technology 2011年第1期26卷 195-202页

作者：卢少平张松海 department of Computer Science and technology Tsinghua University Beijing Engineering Research Center for Intelligent Processing of Visual media and Content Security

In this paper, we present a video coding scheme which applies the technique of visual saliency computation to adjust image fidelity before compression. To extract visually salient features, we construct a spatio-temporal saliency map by analyzing the video using a combined bottom-up and top-down visual saliency model. We then use an extended bilateral filter, in which the local intensity and spatial scales are adjusted according to visual saliency, to adaptively alter the image fidelity. Our implementation is based on the H.264 video encoder JM12.0. Besides evaluating our scheme with the H.264 reference software, we also compare it to a more traditional foreground-background segmentation-based method and a foveation-based approach which employs Gaussian blurring. Our results show that the proposed algorithm can improve the compression ratio significantly while effectively preserving perceptual visual quality.

关键词： visual saliency bilateral filter fidelity adjustment region-of-interest encoder

Topic-aware pivot language approach for statistical machine translation

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Journal of Zhejiang University-Science C(Computers and Electronics) 2014年第4期15卷 241-253页

作者： Jin-song SU Xiao-dong SHI Yan-zhou HUANG Yang LIU Qing-qiang WU Yi-dong CHEN Huai-lin DONG Software School Xiamen University Center for Digital media Computing Xiamen University Cognitive Science department Xiamen University department of Computer Science and technology Tsinghua University

The pivot language approach for statistical machine translation(SMT) is a good method to break the resource bottleneck for certain language pairs. However, in the implementation of conventional approaches, pivotside context information is far from fully utilized, resulting in erroneous estimations of translation probabilities. In this study, we propose two topic-aware pivot language approaches to use different levels of pivot-side context. The first method takes advantage of document-level context by assuming that the bridged phrase pairs should be similar in the document-level topic distributions. The second method focuses on the effect of local context. Central to this approach are that the phrase sense can be reflected by local context in the form of probabilistic topics, and that bridged phrase pairs should be compatible in the latent sense distributions. Then, we build an interpolated model bringing the above methods together to further enhance the system performance. Experimental results on French-Spanish and French-German translations using English as the pivot language demonstrate the effectiveness of topic-based context in pivot-based SMT.

关键词： Natural language processing Pivot-based statistical machine translation Topical context information

A nut-type ultrasonic motor and its application in the focus system

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Chinese Science Bulletin 2009年第20期54卷 3778-3783页

作者： ZHOU TieYing ZHANG Yun CHEN Yu LU CunYue FU DeYong LI Yi HU XiaoPing department of Physics Tsinghua University Beijing 100084 China Boly media Communications LTD (Shenzhen) Shenzhen 518031 China

This article reports a screw-driven polyhedron linear ultrasonic motor(USM) of *** is comprised of a stator,which is a threaded metal nut bonded with piezoelectric plates on its external surface,and a rotor with external threads,which engage with the internal threads of the stator.A traveling wave in the plane is stimulated on the stator when harmonic electric signals are applied to the piezoelectric *** traveling wave drives the rotor to rotate,and the threads transform the rotation into a linear *** lens can be fixed in the rotor and realize the integrated design of the auto focus *** structure can omit retarder and directly drive to obtain a high accuracy of positioning,and it is shockproof.A mini AF cellular phone module(8.5 mm×8.5 mm×5.9 mm) driven by this motor was made and an image resolution of 3-5 MP was obtained in the module prototypes of the cellular phone.

关键词：自动对焦系统超声波电机螺母应用直线运动直接驱动迷你手机超声波马达

Physics-constrained deep learning for data assimilation of subsurface transport

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能源与人工智能(英文) 2021年第1期3卷 104-114页

作者： Haiyi Wu Rui Qiao department of Mechanical Engineering Virginia TechBlacksburgVA 24061USA

Data assimilation of subsurface transport is important in many energy and environmental applications,but its solution is typically *** this work,we build physics-constrained deep learning models to predict the full-scale hydraulic conductivity,hydraulic head,and concentration fields in porous media from sparse measure-ment of these *** model is developed based on convolutional neural networks with the encoding-decoding *** model is trained by minimizing a loss function that incorporates residuals of governing equations of subsurface transport instead of using labeled *** trained,the model predicts the unknown conductivity,hydraulic head,and concentration fields with an average relative errormedia with different conductivities and transport under different Péclet number(0.5

关键词： Physics-constrained deep learning Data assimilation Subsurface transport Convolutional encoder-decoder

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Open Journal of Preventive Medicine 2015年第10期5卷 416-425页

作者： Afnan H. Saaty Debra B. Reed Weiwu Zhang Mallory Boylan Food and Nutrition department King Abdulaziz University Jeddah Kingdom of Saudi Arabia Nutritional Sciences department Texas Tech University Lubbock TX USA media and Communication department Texas Tech University Lubbock TX USA

Objective: As a needs assessment for intervention, quantitative and qualitative methods were used to examine attitude, subjective norms, perceived behavioral control, intention, knowledge, and weight control status related to physical activity in female university students within the Theory of Planned Behavior (TPB). Methods: A two-phase mixed method design was used. In Phase I, 362 students participated in an online survey, and in Phase II, 33 students participated in five focus group discussions. Ages of participants ranged from 18 to 45 years old, with 18 - 25 year olds making up over 74% of the sample. Results: Attitude, subjective norms, and perceived behavioral control, along with weight control status of trying to lose weight, were found to be significant predictors of intention to follow physical activity recommendations, which in turn were the strongest predictor of physical activity. Knowledge was not found to be significant. Group discussions revealed barriers to meeting physical activity recommendations, which included lack of companionship and social support, lack of motivation, time and cost restrictions, and lack of privacy in the gym. Social norms exerted both positive and negative influences. Conclusion: The mixed method approach provided a deeper insight into the influential factors pertaining to physical activity among female students, and results could be used in further research to develop effective interventions.

关键词： Physical Activity Theory of Planned Behavior Female University Students Mixed Methods