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An efficient parallel algorithm of variational nodal method for heterogeneous neutron transport problems

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Nuclear Science and Techniques 2024年第4期35卷 29-45页

作者： Han Yin Xiao-Jing Liu teng-Fei zhang School of Nuclear Science and Engineering Shanghai Jiao Tong UniversityShanghai 2002040China

The heterogeneous variational nodal method(HVNM)has emerged as a potential approach for solving high-fidelity neutron transport ***,achieving accurate results with HVNM in large-scale problems using high-fidelity models has been challenging due to the prohibitive computational *** paper presents an efficient parallel algorithm tailored for HVNM based on the Message Passing Interface *** algorithm evenly distributes the response matrix sets among processors during the matrix formation process,thus enabling independent construction without *** the formation tasks are completed,a collective operation merges and shares the matrix sets among the *** the solution process,the problem domain is decomposed into subdomains assigned to specific processors,and the red-black Gauss-Seidel iteration is employed within each subdomain to solve the response matrix ***-to-point communication is conducted between adjacent subdomains to exchange data along the *** accuracy and efficiency of the parallel algorithm are verified using the KAIST and JRR-3 test *** results obtained with multiple processors agree well with those obtained from Monte Carlo *** parallelization of HVNM results in eigenvalue errors of 31 pcm/-90 pcm and fission rate RMS errors of 1.22%/0.66%,respectively,for the 3D KAIST problem and the 3D JRR-3 *** addition,the parallel algorithm significantly reduces computation time,with an efficiency of 68.51% using 36 processors in the KAIST problem and 77.14% using 144 processors in the JRR-3 problem.

关键词： Neutron transport Variational nodal method Parallelization KAIST JRR-3

Effects of Diesel Concentration on the Thermal Conductivity,Specific Heat Capacity and Thermal Diffusivity of Diesel-Contaminated Soil

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Journal of Thermal Science 2024年第2期33卷 696-709页

作者： WU Yuhao WU Yuefei LUO Gubai zhang teng WANG Qing FAN Liwu SONG Xin YU Zitao Key Laboratory of Clean Energy and Carbon Neutrality of Zhejiang Province Zhejiang UniversityHangzhou310027China State Key Laboratory of Clean Energy Utilization Zhejiang UniversityHangzhou310027China Institute of Thermal Science and Power Systems School of Energy EngineeringZhejiang UniversityHangzhou310027China Center Environmental Protection Technology Company Limited Beijing100176China Institute of Soil Science Chinese Academy of SciencesNanjing210008China

High energy consumption is a serious issue associated with in situ thermal desorption(TD)remediation of sites contaminated by petroleum hydrocarbons(PHs).The knowledge on the thermophysical properties of contaminated soil can help predict accurately the transient temperature distribution in a remediation site,for the purpose of energy ***,such data are rarely reported for PH-contaminated *** this study,by taking diesel as a representative example for PHs,soil samples with constant dry bulk density but different diesel mass concentrations ranging from 0% to 20% were prepared,and the variations of their thermal conductivity,specific heat capacity and thermal diffusivity were measured and analyzed over a wide temperature range between 0℃ and 120℃.It was found that the effect of diesel concentration on the thermal conductivity of soil is negligible when it is below 1%.When diesel concentration is below 10%,the thermal conductivity of soil increases with raising the ***,when diesel concentration becomes above 10%,the change of the thermal conductivity of soil with temperature exhibits the opposite *** is mainly due to the competition between soil minerals and diesel,because the thermal conductivity of minerals increases with temperature,whereas the thermal conductivity of diesel decreases with *** analysis results showed that,compared with temperature,the diesel concentration has more significant effects on soil thermal *** of the diesel concentration,with the increase of temperature,the specific heat capacity of soil increases,while the thermal diffusivity of soil *** addition,the results of a control experiment exhibited that the relative differences of the thermal conductivity of the soil samples containing the same concentration of both diesel and a pure alkane are all below 10%,indicating that the results obtained with diesel in this study can be extended to the family of PHs.A theo

关键词： contaminated soil diesel concentration thermal conductivity specific heat capacity thermal diffusivity thermal desorption fractal model

Tuning the ferroelectricity of Hf0.5Zr0.5O2 with alloy electrodes

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Science China(Information Sciences) 2024年第8期67卷 321-330页

作者： Keqin LIU Bingjie DANG Zhiyu YANG teng zhang Zhen YANG Jinxuan BAI Zelun PAN Ru HUANG Yuchao YANG Beijing Advanced Innovation Center for Integrated Circuits School of Integrated Circuits Peking University School of Electronic and Computer Engineering Peking University Center for Brain Inspired Chips Institute for Artificial Intelligence Peking University Center for Brain Inspired Intelligence Chinese Institute for Brain ResearchBeijing

Tuning ferroelectricity of Hf0.5Zr0.5O2is crucial for facilitating its practical applications in various fields, including in-memory and neuromorphic computing. Previous studies have revealed that the electrodes have a significant influence on ferroelectricity, and changing electrode materials can realize different but discrete ferroelectric polarization values. Here, we introduce an alloy-electrode method, in order to achieve gradual and accurate modulation of ferroelectric polarization, especially useful for matching the polarization charges at the interface of ferroelectric insulators and ferroelectric semiconductors. Au and W electrodes are chosen as baselines for realizing weak and strong ferroelectric polarization, where the intermediate states can be achieved by adjusting the ratio of metals in the Au-W alloy. To demonstrate the generality of this approach, the Cu-W alloy electrode is also realized for tuning ferroelectric polarization. The effect of alloy electrodes on device leakage current, endurance, and retention is evaluated. In addition, the temperature stability of ferroelectric capacitors is tested, where limited changes in both remnant polarization and coercive voltages are observed, showing the great potential of the ferroelectric hafnium oxide. Such gradual modulation of ferroelectric polarization could facilitate the application of Hf0.5Zr0.5O2in in-memory and neuromorphic computing.

关键词： ferroelectric hafnium oxide alloy electrode gradual modulation temperature stability

Atomic tracking of thermally-driven structural evolution in 2D crystals:Case of NbSe_(2)

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InfoMat 2024年第2期6卷 90-98页

作者： Baofei Hou teng zhang Tingting Wang Hongyan Ji Huixia Yang Liangguang Jia Xu Han Jingsi Qiao Yu zhang Liwei Liu Hong-Jun Gao Yeliang Wang School of Integrated Circuits and Electronics&Yangtze Delta Region Academy Beijing Institute of TechnologyBeijingthe People's Republic of China Institute of Physics Chinese Academy of SciencesBeijingthe People's Republic of China

Advanced atomic tracking techniques play a critical role in characterizing structural evolution,elucidating fundamental mechanisms of exotic phenomena and tailoring delicate *** driven structural modulation in 2D crystals,such as the charge density wave(CDW),often leads to intriguing quantum properties,making them a valuable platform for exploring fundamental physics and potential device ***,despite their significance,experimental studies addressing atomic tracking of thermally-driven structural evolution in 2D crystals have been ***,we utilize high-accuracy variable-temperature atomic tracking measurements with scanning tunneling microscopy(STM)to directly observe a series of structural transitions in a model 2D crystal,namely NbSe_(2).With the atomic tracking technique,we confirm the existence of the universal thermally-driven CDW transition hysteresis between the heating and cooling *** transition hysteresis,characterized by a constant temperature offset,represents a new phenomenon of structural *** findings provide a feasible method to track CDW transitions at the atomic scale in 2D crystals,significantly contributing to a better understanding and the potential modulation of these materials'functions in nanodevices.

关键词： 2D crystal atomic tracking technique structural evolution temperature hysteresis

基于辛本征值方法的受约束介电弹性体中褶皱不稳定性的分析

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计算力学学报 2024年第1期41卷 209-216页

作者：张腾雪城大学机械与航空系美国纽约NY 13244

辛弹性力学已广泛应用于弹性学中各种边值问题的精确解、计算表面波模式以及预测多层超弹性薄膜中的表面褶皱。本文展示了辛分析框架还可应用于受约束介电弹性体中的表面褶皱。机械和电位移向量是两个基本变量来描述介电弹性体中机械变... 详细信息

辛弹性力学已广泛应用于弹性学中各种边值问题的精确解、计算表面波模式以及预测多层超弹性薄膜中的表面褶皱。本文展示了辛分析框架还可应用于受约束介电弹性体中的表面褶皱。机械和电位移向量是两个基本变量来描述介电弹性体中机械变形与电场紧密耦合。褶皱的临界电压可以通过引入基本变量的对偶变量来从辛本征值问题中解决。本文采用扩展的W-W(Wittrick-Williams)算法和精确的积分方法,准确而高效地解决制定的辛本征值问题的本征值。通过将褶皱电压和波数与有无表面能的褶皱基准结果进行比较,验证了辛分析的有效性。辛分析框架简洁且适用于其他不稳定问题,如分层电介质弹性体、磁弹性不稳定性以及层压复合结构的微观和宏观不稳定性。

关键词：辛介电弹性体褶皱本征值分析

Organic Integration of Traditional Chinese and Western Medicines—Future of Clinical Practice Guidelines of Integrated Traditional Chinese and Western Medicines

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Chinese Journal of Integrative Medicine 2024年第4期30卷 359-365页

作者： XIE Ying-lan HAN Fei JIN Ying-hui DING Yan-bing GUO Jing JI Dong-xiao zhang teng CHENXiao-min SHANG Hong-cai Department of Traditional Chinese Medicine Encephalopathy Hubei Provincial Hospital of Traditional Chinese MedicineWuhan(430074)China Department of Traditional Chinese Medicine Encephalopathy Hubei Province Traditional Chinese Medicine Research InstituteWuhan(430074)China Xuanwu Hospital of Traditional Chinese Medicine Beijing(100000)China Center for Evidence-Based and Translational Medicine Zhongnan Hospital of Wuhan UniversityWuhan(430074)China College of Acupuncture and Massage College of Health and RehabilitationNanjing University of Chinese MedicineNanjing(210023)China Department of Ophthalmology Huaihe Hospital of Henan UniversityKaifengHenan Province(475000)China Ministry of Education and Beijing Key Laboratory of Internal Medicine of Traditional Chinese Medicine Dongzhimen Hospital of Beijing University of Traditional Chinese Medicine/Ministry of Education and Beijing Key Laboratory of Internal Medicine of Traditional Chinese MedicineBeijing(100700)China

The transformation and implementation of clinical practice guidelines for integrated traditional Chinese medicine(TCM)and Western medicine(WM)is crucial to the adoption of medical science and technological findings and is an important way for TCM to be made available to the ***,clinical practice guidelines(CPGs)of TCM and WM integration in recent years was analyzed to clarify the current situation and problems in the existing guidelines according to the following four perspectives:(1)perspective of TCM and WM integration in guidelines,(2)diagnosis Using integrated TCM and WM,(3)integration of TCM and WM treatment,(4)promoting TCM and WM ***,the information and quality evaluation of CPGs for integrated Chinese and Western medicine in 2020–2022 were analyzed to explore the degree and methods of integration of Chinese and Western medicine *** last this study aimed to lay a foundation for the further establishment of Chinese characteristic,repeatable,and calculable clinical practice guidelines of TCM and WM integration.

关键词： clinical practice guidelines integrated traditional Chinese and Western medicine organic integration

High critical current density in Li_(6.4)La_(3)Zr_(1.4)Ta_(0.6)O_(12) electrolyte via interfacial engineering with complex hydride

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Rare Metals 2024年第2期43卷 692-701页

作者： Ying-Tong Lv teng-Fei zhang Zhao-Tong Hu Guang-Lin Xia Ze-Ya Huang Zhen-Hua Liu Li-Hua Que Cai-Ting Yuan Fang-Qin Guo Takayuki Ichikawa Xue-Bin Yu College of Materials Science and Technology Nanjing University of Aeronautics and AstronauticsNanjing210016China Centre for Hydrogenergy College of Materials Science and TechnologyNanjing University of Aeronautics and AstronauticsNanjing210016China Department of Materials Science Fudan UniversityShanghai200433China Graduate School of Advanced Science and Engineering Hiroshima University1-4-1 KagamiyamaHigashi-Hiroshima739-8527Japan

Garnet-type solid-state batteries(SSBs)are considered to be one of the most promising candidates to realize next-generation lithium metal batteries with high energy density and ***,the dendrite-induced short-circuit and the poor interfacial contact impeded the practical ***,interface engineering to achieve low interfacial resistance without high temperature calcination was developed,which Li_(6.4)La_(3)Zr_(1.4)Ta_(0.6)O_(12)(LLZTO)was simply coated with complex hydride(Li_(4)(BH_(4))_(3)I(3L1L))in various mass ratios n(Li_(4)(BH_(4))_(3)I)-(100−n)LLZTO(10≤n≤40).The interfacial conductivity increases by more than three orders of magnitude from 8.29×10^(−6)S·cm^(−1)to 1.10×10^(−2)S·cm^(−1).Symmetric Li cells exhibit a high critical current density(CCD)of 4.0 mA·cm^(−2) and an excellent cycling stability for 200 h at 4.0 mA·cm^(−2).SSBs with polymeric sulfur-polyacrylonitrile(SPAN)cathode achieve a high discharge capacity of 1149 mAh·g^(−1) with a capacity retention of 91%after 100 cycles(0.2 C).This attempt guides a simple yet efficient strategy for obtaining a stable Li/LLZTO interface,which would promote the development of solid-state batteries.

关键词： Hydrides Li_(6.4)La_(3)Zr_(1.4)Ta_(0.6)O_(12)(LLZTO) Critical current density Solid-state electrolytes(SSEs) Lithium-sulfur batteries

Tuning the ferroelectricity of HfZrOwith alloy electrodes

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Science China(Information Sciences) 2024年

Tuning ferroelectricity of Hf0.5Zr0.5O2 is crucial for facilitating its practical applications in various fields, including in-memory and neuromorphic computing. Previous studies have revealed that the electrodes have a significant influence on ferroelectricity, and changing electrode materials can realize different but discrete ferroelectric polarization values. Here, we introduce an alloy-electrode method, in order to achieve gradual and accurate modulation of ferroelectric polarization, especially useful for matching the polarization charges at the interface of ferroelectric insulators and ferroelectric semiconductors. Au and W electrodes are chosen as baselines for realizing weak and strong ferroelectric polarization, where the intermediate states can be achieved by adjusting the ratio of metals in the Au-W alloy. To demonstrate the generality of this approach, the Cu-W alloy electrode is also realized for tuning ferroelectric polarization. The effect of alloy electrodes on device leakage current, endurance, and retention is evaluated. In addition, the temperature stability of ferroelectric capacitors is tested, where limited changes in both remnant polarization and coercive voltages are observed, showing the great potential of the ferroelectric hafnium oxide. Such gradual modulation of ferroelectric polarization could facilitate the application of Hf0.5Zr0.5O2 in in-memory and neuromorphic computing.

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如何实现“黑箱”下的算法治理?——平台推荐算法监管的测量实验与策略探索

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公共行政评论 2024年第1期17卷 25-44,M0003页

作者：张楠闫涛张腾清华大学公共管理学院清华大学计算社会科学与国家治理实验室山西省委网信办

近年来,平台推荐算法的快速发展和广泛应用深刻改变了互联网信息内容的供给方式,同时也引发了一系列算法风险与现实问题。平台推荐算法治理与监管成为政府规范算法应用的重点内容之一,无论是算法备案制度的探索,还是实现算法透明化的设... 详细信息

近年来,平台推荐算法的快速发展和广泛应用深刻改变了互联网信息内容的供给方式,同时也引发了一系列算法风险与现实问题。平台推荐算法治理与监管成为政府规范算法应用的重点内容之一,无论是算法备案制度的探索,还是实现算法透明化的设想,均面临着一定的困难和挑战。在不打开算法“黑箱”的前提下,平台推荐算法规制与监管是否有可行之道?论文基于机器行为学思想,采用实验方法,以用户视角对推荐结果进行跟踪记录,通过实验数据的对比分析,验证了平台推荐算法结果差异的可测性。基于实验结果,论文提出了通过对不同平台推荐结果进行大规模数据测试和检验,测量平台推荐算法运行逻辑与推荐效果,从而实现“黑箱”下有效的逆向监管,以期丰富未来算法治理的选择。

关键词：推荐算法算法治理算法监管机器行为学