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Electrospinning synthesis of novel lithium-rich 0.4Li2MnO3.0.6LiNi1/3CO1/3Mn1/3O2 nanotube and its electrochemical performance as cathode of lithium-ion battery

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Advances in Manufacturing 2016年第1期4卷 79-88页

作者： Lei-Lei Cui Xiao-Wei Miao yu-Feng Song Wen-Ying fang Hong-Bin Zhao Jian-hui fang Department of Chemistry Shanghai UniversityShanghai 200444 People's Republic of China Shanghai Key Laboratory of Mechanics in EnergyEngineering Shanghai University Shanghai 200072People's Republic of China Department of Chemical Engineering University ofWaterloo Waterloo N2L3G1 Canada

In this study, a lithium-rich 0.4Li2MnO3.0.6LiNi1/3Co1/3Mn1/3O2 nanotube layered cathode synthesized by novel electrospinning is reported, and the effects of temperature on the electrochemical performance and morphologies are investigated. The crystal structure is characterized by X-ray diffraction patterns, and refined by two sets of diffraction data （R-3m and C2/m）. Refined crystal structure is 0.4Li2MnO3.0.6LiNi1/3COl/3Mn13O2 compos- ite. The inductively coupled plasma optical emission spec- trometer and thermogravimetric and differential scanning calorimetry analysis measurement supply reference to opti- mize the calcination temperature and heat-treatment time. The morphology is characterized by scanning and high- resolution transmission electron microscope techniques, and the micro-nanostructured hollow tubes of Li-rich 0.4Li2MnO3-0.6LiNil/3COl/3Mn1/3O2 composite with outer diameter of 200-400 nm and the wall thickness of 50-80 nm are synthesized successfully. The electrochemical evaluation shows that 0.4Li2MnO3.0.6LiNi1/3Cov3Mn1/3O2 sintered at 800 ℃ for 8 h delivers the highest capacity of the first dis- charge capacity of 267.7 mAh/g between 2.5 V and 4.8 V at 0.1C and remains 183.3 mAh/g after 50 cycles. The electro- spinning method with heat-treatment to get micro-nanos- tructured lithium-rich cathode shows promising application inlithium-ion batteries with stable electrochemical performance and higher C-rate performance for its shorter Li ions transfer channels and stable designed structure.

关键词： Electrospinning Cathode - Nanotube Lithium-rich Lithium battery

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Changes in vegetation and soil properties during recovery of a subtropical forest in South China

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Journal of Mountain Science 2018年第1期15卷 46-58页

作者： HUANG fang-fang ZHANG Wei-qiang GAN Xian-hua HUANG yu-hui GUO yue-dong WEN Xiao-ying Guangdong Provincial Key Laboratory of Silviculture Protection and Utilization Guangdong Academy of Forestry

Secondary forests account for a large amount of subtropical forest due to persistent anthropogenic disturbance in *** interaction between vegetation and soil during recovery process is rather complex and dependent on forest *** how vegetation and soil properties changes and how their relationship develops in secondary forests is key to effective forest restoration and *** we explored the patterns of vegetation and soil properties as well as their correlations during forest recovery process in a subtropical forest in south *** of three forest types,i.e.,broadleaf-conifermixedforest,broadleaved forest and old growth stand,were established to represent the recovery *** results showed that diversity patterns in the tree,shrub and herb layers were different:in the tree layer the species diversity peaked at the intermediate stage,while in the understory layers it decreased *** of the soil factors showed an increasing trend,and different effects of soil factors were found for the three layers as well as for the two spatial ***,our results suggested that vegetation and soil might be interdependent during the recovery *** studies are needed on exploring how vegetation interplays with soil at different scales and how nutrient limitations affects the vegetation development in a chronosequence.

关键词： Forest recovery Vegetation change Soil property Subtropical Succession

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A reviving templating method for multiple nanostructures

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Science China Materials 2017年第5期60卷 461-462页

作者： hui-hui Li Shu-Hong yu Division of Nanomaterials & Chemistry Hefei National Laboratory for Physical Sciences at the Microscale Department of Chemistry University ofScience and Technology of China Hefei 230026 China

Binary materials,comprised by two dissimilar components in one matrix,already exist in nature from the subatomic to the universal scale with different kinds of forms(e.g.,nuclei and electrons,matter and antimatter)[1]... 详细信息

关键词：英语阅读理解材料科学

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单轴应变对本征和N掺杂4H-SiC电子结构的影响

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原子与分子物理学报 2025年第3期42卷 173-179页

作者：秦彦军张建强杨慧雅方峥范晓珍邝富丽叶慧群方允樟浙江师范大学物理与电子信息工程学院金华321004 新疆理工学院理学院阿克苏843100 浙江旅游职业学院杭州311231

采用基于密度泛函理论的第一性原理方法,研究了单轴应变对本征和N掺杂4H-SiC电子结构的影响.研究表明应变可以有效调控本征和N掺杂4H-SiC的带隙,在拉应变作用下,带隙单调减小;而在压应变作用下,带隙先增大后减小,当压应变为-1%时,带隙... 详细信息

采用基于密度泛函理论的第一性原理方法,研究了单轴应变对本征和N掺杂4H-SiC电子结构的影响.研究表明应变可以有效调控本征和N掺杂4H-SiC的带隙,在拉应变作用下,带隙单调减小;而在压应变作用下,带隙先增大后减小,当压应变为-1%时,带隙达到最大值.对态密度的分析可知本征和N掺杂4H-SiC的价带顶主要来自Si 3p和C 2p态电子,导带底主要来自Si 3p态电子,C 2p态和Si 3p态通过影响价带顶和导带底从而导致应变结构中带隙发生变化.通过Mulliken布局和差分电荷密度分析可知,随着晶格常数的增加Si原子向C原子和N原子转移的电荷减少,同时Si-C原子和Si-N原子之间的共价性减弱.

关键词： 4H-SiC 单轴应变电子结构第一性原理

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Differentially Private Event Histogram Publication on Sequences overGraphs

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Journal of Computer Science & Technology 2017年第5期32卷 1008-1024页

作者： Ning Wang yu Gu Jia Xu fang-fang Li Ge yu College of Computer Science and Engineering Northeastern University Shenyang 110819 China College of Computer Electronics and Information Guangxi University Nanning 530004 China

The big data era is coming with strong and ever-growing demands on analyzing personal information and footprints in the cyber world. To enable such analysis without privacy leak risk, differential privacy (DP) has been quickly rising in recent years, as the first practical privacy protection model with rigorous theoretical guarantee. This paper discusses how to publish differentially private histograms on events in time series domain, with sequences of personal events over graphs with events as edges. Such individual-generated sequences commonly appear in formalized industrial workflows, online game logs, and spatial-temporal trajectories. Directly publishing the statistics of sequences may compromise personal privacy. While existing DP mechanisms mainly target at normalized domains with fixed and aligned dimensions, our problem raises new challenges when the sequences could follow arbitrary paths on the graph. To tackle the problem, we reformulate the problem with a three-step framework, which 1) carefully truncates the original sequences, trading off errors introduced by the truncation with those introduced by the noise added to guarantee privacy, 2) decomposes the event graph into path sub-domains based on a group of event pivots, and 3) employs a deeply optimized tree-based histogram construction approach for each sub-domain to benefit with less noise addition. We present a careful analysis on our framework to support thorough optimizations over each step of the framework, and verify the huge improvements of our proposals over state-of-the-art solutions.

关键词： differential privacy histogram publication sequence graph

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Formation of free-surface vortex and vortex suppression by rotating stopper-rod at end of tundish casting

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Journal of Iron and Steel Research International 2024年第5期31卷 1104-1116页

作者： Qing fang Peng Zhao Hua Zhang Wen-hao Zhou Gang yu Jia-hui Wang Hong-wei Ni The State Key Laboratory of Refractories and Metallurgy Wuhan University of Science and TechnologyWuhan430081HubeiChina Hunan Valin Xiangtan Iron and Steel Co. Ltd.Xiangtan411101HunanChina Hubei Provincial Key Laboratory for New Processes of Ironmaking and Steelmaking Wuhan University of Science and TechnologyWuhan430081HubeiChina

A rotating stopper-rod technique was proposed to suppress the formation of free-surface vortex in the *** large eddy simulation model coupled with volume of fluid model was developed to study the steel–slag–gas three-phase flow *** critical slag entrapment height of the free-surface vortex and mass of residual steel were predicted at different rotating speeds(30,60,90 and 120 r/min)of the rotating *** numerical model was verified by water model *** results showed that by rotating the stopper-rod in the opposite direction of the vortex above the submerged entry nozzle,the formation of vortex can be effectively disturbed and the critical height of the free-surface vortex can be *** for the 2nd strand,when the rotating speeds are 30,60,90 and 120 r/min,the critical height of the free-surface vortex above the 2nd strand is 7.3,4.7,6.3 and 7.4 cm,respectively.A reasonable rotating speed should be 60 r/min,which can reduce about 2 tons of residual *** rotating speeds just can reduce about 1.6 tons of residual steel.

关键词： Tundish Free-surface vortex Stopper-rod Numerical simulation Multiphase flow

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NN-based Output Tracking for More General Stochastic Nonlinear Systems with Unknown Control Coefficients

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International Journal of Automation and computing 2017年第3期14卷 350-359页

作者： Na Duan hui-fang Min School of Electrical Engineering & Automation Jiangsu Normal UniversityXuzhou 221116 China

This paper considers the output tracking problem for more general classes of stochastic nonlinear systems with unknown control coefficients and driven by noise of unknown covariance. By utilizing the radial basis function neural network approximation method and backstepping technique, we successfully construct a controller to guarantee the solution process to be bounded in *** tracking error signal is 4th-moment semi-globally uniformly ultimately bounded（SGUUB） and can be regulated into a small neighborhood of the origin in probability. A simulation example is given to demonstrate the effectiveness of the control scheme.

关键词： Stochastic nonlinear systems unknown control coefficients output tracking neural networks backstepping

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STRUCTURE AND RESTRUCTURING OF BEIJING-TIANJIN-HEBEI MEGALOPOLIS IN CHINA

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Chinese Geographical Science 2006年第1期16卷 1-8页

作者： yu Tao-fang School of Architecture Tsinghua University Beijing 100084 P. R. China

Scott proposes to use the term global city-regions to designate the phenomena that bear some resemblance to the "world cities" firstly identified by Hall and Friedmann and Wolff, and to the "global cities" of Sassen but whose essential social logic and contextual characteristics have evolved considerably since these pioneering studies were published. In simple geographical terms, a global city-region can be refered to comprise any major metropolitan area or any contiguous set of metropolitan areas together with a surrounding hinterland of variable extent-itself a locus of scattered urban settlements-whose internal economic and political affairs are bound up in intricate ways in intensifying and far-flung extra-national relationships. Scott refers to these extra-national relationships as a symptom of "globalization". As economic motors and political actors, the global city regions have been regarded as crucial parts of development strategies in China. In the "Eleventh Five-year Plan" issued by the National Development and Reform Commission of P. R. China, the Beijing-Tianjin-Hebei Province (Jing-Jin-Ji) region, one of the typical megalopolises or global city regions in the East Coastal China is paid more attention. This paper first analyzes the regional structure of the Jing-Jin-Ji region based on data of the fifth national population census of China. And then through the changes of the population growth, the dynamic process and mechanisms of the regional restructuring in the Jing-Jin-Ji is explored and discussed.

关键词： regional structure regional restructuring Beijing-Tianjin-Hebei (Jing-Jin-Ji)

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Low-computation certificateless hybrid signcryption scheme

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Frontiers of Information Technology & Electronic Engineering 2017年第7期18卷 928-940页

作者： hui-fang yu Bo YANG School of Computer Qinghai Normal University Xining 810008 China School of Computer Science Shaanxi Normal University Xi 'an 710062 China State Key Laboratory of Information Security Institute of Information Engineering Chinese Academy of Sciences Beijing 100093 China

Hybrid signcryption is an important technique signcrypting bulk data using symmetric encryption. In this paper, we apply the technique of certificateless hybrid signcryption to an elliptic-curve cryptosystem, and construct a low-computation certificateless hybrid signcryption scheme. In the random oracle model, this scheme is proven to have indistinguishability against adaptive chosen-ciphertext attacks （IND-CCA2） under the elliptic-curve computation Diffie-Hellman assumption. Also, it has a strong existential unforgeability against adaptive chosen-message attacks （sUF-CMA） under the elliptic-curve discrete logarithm assumption. Analysis shows that the cryptographic algorithm does not rely on pairing operations and is much more etticient than other algorithms. In addition, it suits well to applications in environments where resources are constrained, such as wireless sensor networks and ad hoc networks.

关键词： Hybrid signcryption Scalar multiplication Certificateless cryptosystem Provable security

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Drag reduction and shear resistance properties of ionomer and hydrogen bond systems based on lauryl methacrylate

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Petroleum Science 2011年第3期8卷 357-364页

作者： yu Ping Li Changyu Zhang Changqiao Chen Shiwei fang Shu Sun hui School of Chemistry and Chemical Engineering Shandong University Jinan 250061 China

Based on molecular dynamics simulation results, a lauryl methacrylate polymer with drag reduction and shear resistance properties was designed, and synthesized by emulsion polymerization using 2-vinyl pyridine and methyl methacrylate as the polar polymerization monomer. After ionization of lauryl methacrylate polymer, an ion-dipole interaction based drag reduction agent （DRA） was obtained. The existence of ion-dipole interaction was proven through characterization of the drag-reducing agent from its infrared （IR） spectrum. The pilot-scale reaction yield of the DRA under optimum conditions was investigated, and the drag reduction and shear resistance properties were measured. The results show that： l） The ion-dipole or hydrogen bonding interaction can form ladder-shaped chains, therefore the synthesized DRA has shear resistance properties; 2） The larger the molecular weight （MW） and more concentrated the distribution of MW, the better the drag reduction efficiency and the performance of the ionomer system was superior to that of the hydrogen bonding system; 3） With increasing shear frequency, the drag-reduction rates of both the DRAs decreased, and the drag reduction rate of the ionomer system decreased more slowly than of the corresponding hydrogen bonding system. From the point of view of drag reduction rate and shear resistance property, the ionomer system is more promising than the hydrogen bonding system

关键词： Molecular design ion-dipole interaction hydrogen bonding drag reduction rate shearresistance property

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