检索结果-南通市图书馆

An Efficient Boron Source Activation Strategy for the Low‑Temperature Synthesis of Boron Nitride Nanotubes

在线全文

学校读者我要写书评

暂无评论

Nano-Micro Letters 2025年第1期17卷 548-558页

作者： Ying Wang Kai zhang Liping Ding Liyun Wu Songfeng E Qian He Nanyang Wang hui Zuo Zhengyang Zhou feng Ding Yue hu jin zhang Yagang Yao National Laboratory of Solid State Microstructures College of Engineering and Applied SciencesJiangsu Key Laboratory of Artificial Functional Materialsand Collaborative Innovation Center of Advanced MicrostructuresNanjing UniversityNanjing 210093People’s Republic of China School of Electronic Information and Artificial Intelligence Shaanxi University of Science&TechnologyXian 710000People’s Republic of China College of Bioresources Chemical and Materials Engineering Shaanxi University of Science&TechnologyXian 710000People’s Republic of China Key Laboratory of Carbon Materials of Zhejiang Province College of Chemistry and Materials EngineeringWenzhou UniversityWenzhou 325000People’s Republic of China Shenzhen Institutes of Advanced Technology Chinese Academy of SciencesShenzhen 518000People’s Republic of China College of Chemical and Molecular Engineering Peking UniversityBeijing 100871People’s Republic of China

Lowering the synthesis temperature of boron nitride nanotubes(BNNTs)is crucial for their *** primary reason for adopting a high temperature is to enable the effective activation of highmelting-point solid *** this study,we developed a novel approach for efficiently activating boron by introducing alkali metal compounds into the conventional MgO–B *** approach can be adopted to form various low-melting-point AM–Mg–B–O growth *** growth systems have improved catalytic capability and reactivity even under low-temperature conditions,facilitating the synthesis of BNNTs at temperatures as low as 850℃.In addition,molecular dynamics simulations based on density functional theory theoretically demonstrate that the systems maintain a liquid state at low temperatures and interact with N atoms to form BN *** findings offer novel insights into the design of boron activation and are expected to facilitate research on the low-temperature synthesis of BNNTs.

关键词： Boron nitride nanotubes Low-temperature Boron activation Density functional theory

Fe、Ir掺杂MoS_(2)表面对N_(2)气敏吸附与解离反应性能提升的第一性原理研究

在线全文

学校读者我要写书评

暂无评论

原子与分子物理学报 2025年第1期42卷 13-19页

作者：肖香珍胡林峰张建伟河南科技学院新乡453003

基于第一性原理方法,采用周期性平板模型,研究了N_(2)分子在掺杂体系TM-MoS_(2)(TM=Fe、Ir)表面的吸附和解离行为.研究表明:N_(2)分子在TM-MoS_(2)(TM=Fe、Ir)表面吸附能依次为0.62和0.47 eV,而完整MoS_(2)表面的吸附能只有0.08 eV,说... 详细信息

基于第一性原理方法,采用周期性平板模型,研究了N_(2)分子在掺杂体系TM-MoS_(2)(TM=Fe、Ir)表面的吸附和解离行为.研究表明:N_(2)分子在TM-MoS_(2)(TM=Fe、Ir)表面吸附能依次为0.62和0.47 eV,而完整MoS_(2)表面的吸附能只有0.08 eV,说明掺杂之后对N_(2)表现出略好的吸附性能.差分电荷密度分析表明,N_(2)吸附后,掺杂Fe、Ir原子与两个N原子之间电荷有所增加,N-N键之间的区域电荷密度减少,N-N键的强度减弱.态密度计算结果发现,N_(2)在吸附过程中,主要是N原子的2p_(y)、2p_(z)轨道与Ir的5d_(xy)和5d_(z^(2))以及Fe的3d_(xy)和3d_(z^(2))发生杂化作用.通过分析解离活化能,N_(2)在掺杂体系TM-MoS_(2)(TM=Fe、Ir)表面解离需要活化能均较高,且远大于在相应掺杂表面的吸附能,说明N_(2)在掺杂体系TM-MoS_(2)(TM=Fe、Ir)表面解离应该表现为分子吸附或脱附.

关键词： Fe、Ir 掺杂单层MoS_(2) N_(2) 吸附与解离活化能密度泛函理论

维普期刊数据库博看期刊

Modelling of the Vortex-Induced Motion of A Single-Column Platform with Non-Linear Mooring Stiffness Using the Coupled Wake Oscillators

在线全文

学校读者我要写书评

暂无评论

China Ocean Engineering 2019年第4期33卷 459-467页

作者： hu xiao-feng zhang Xin-shu YOU Yun-xiang DUAN jin-long State Key Laboratory of Ocean Engineering School of Naval Architecture Ocean and Civil Engineering Shanghai Jiao Tong University Shanghai 200240 China Collaborative Innovation Center for Advanced Ship and Deep-Sea Exploration (CISSE) School of Naval Architecture Ocean and Civil Engineering Shanghai Jiao Tong University Shanghai 200240 China

A phenomenological model for predicting the vortex-induced motion (VIM) of a single-column platform with non- linear stiffness has been proposed. The VIM model is based on the couple of the Duffing-van der Pol oscillators and the motion equations with non-linear terms. The model with liner stiffness is presented for comparison and their results are compared with the experiments in order to calibrate the model. The computed results show that the predicted VIM amplitudes and periods of oscillation are in qualitative agreements with the experimental data. Compared with the results with linear stiffness, it is found that the application of non-linear stiffness causes the significant reductions in the in-line and transverse motion amplitudes. Under the non-linear stiffness constraint, the lock-in behavior is still identified at 8

关键词： vortex-induced motion single-column platform wake oscillators non-linear stiffness

REAL-TIME FLOOD FORECASTING METHOD WITH 1-D UNSTEADY FLOW MODEL

在线全文

学校读者我要写书评

暂无评论

Journal of Hydrodynamics 2007年第2期19卷 150-154页

作者： MU jin-bin zhang xiao-feng State Key Laboratory of Water Resources and Hydropower Engineering Science Wuhan University Wuhan 430072China

A real-time forecasting method coupled with the I-D unsteady flow model with the recursive least-square method was developed. The 1-D unsteady flow model was modified by using the time-variant parameter and revising it dynamically through introducing a variable weighted forgetting factor, such that the output of the model could be adjusted for the real time forecasting of floods. The application of the new real time forecasting model in the reach from Yichang to Luoshan of the Yangtze River was demonstrated. Computational result shows that the forecasting accuracy of the new model is much higher than that of the original 1-D unsteady flow model. The method developed is effective for flood forecasting, and can be used for practical operation in the flood forecasting.

关键词： unsteady flow hydraulic model least squares,time variant forgetting factor real-time forecasting

Novel Cylinder Movement Modeling Method Based on Aerodynamics

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Mechanical Engineering 2017年第5期30卷 1193-1202页

作者： Jian-Qing zhang xiao-Mei hu jin-Sheng Kang feng Xiong Ning Zeng School of Mechatronic Engineering and Automation Key Laboratory of Intelligent Manufacturing and RoboticsShanghai University College of Engineering Design and Physical SciencesBrunel University London

The cylinder movement is affected by multiple factors and it is difficult to establish the accurate movement model of the cylinder. In order to improve the reliability of the production line design and to speed up the production line debugging, a novel cylinder movement modeling method based on aerodynamics is proposed. The kinetic theory, thermodynamic theory and kinematics knowledge are applied and integrated various factors which affect the movement characteristics of the cylinder are considered. According to the proposed mathematical model of cylinder movement, thecombined simulation software of cylinder movement based on Visual Studio and Visual Component （3D Create） is developed to calculate thevelocity, accel- eration and movement time of the cylinders during the running of the assembly line. Comparison results of cylinder＇s movement time under different intake air and displacement show that the mathematical model of cylinder movement based on aerodynamic is more accurate and the degree of fittingis 0.9846, which proves the effectiveness of the combined simulation software of cylinder movement. By the cylinder movement modeling method based on aerodynamic, accurate value of takt and the debug parameters can be calculated as a reference for the designers and debuggers of the cylinder-driven assembly lines.

关键词： Aerodynamics Thermodynamics Cylindercharacteristic Combined simulation

Numerical study via total Lagrangian smoothed particle hydrodynamics on chip formation in micro cutting

在线全文

学校读者我要写书评

暂无评论

Advances in Manufacturing 2020年第2期8卷 144-159页

作者： jin-Shi Wang xiao-Dong zhang feng-Zhou Fang State Key Laboratory of Precision Measuring Technology and Instruments Centre of Micro/Nano Manufacturing Technology(MNMT)Tianjin UniversityTianjin 300072People's Republic of China Centre of Micro/Nano Manufacturing Technology(MNMT-Dublin) University College DublinDublinIreland

Numerical simulation is an effective approach in studying cutting *** widely used methods for cutting simulation include finite element analysis and molecular ***,there exist some intrinsic shortcomings when using a mesh-based formulation,and the capable scale of molecular dynamics is extremely *** contrast,smoothed particle hydrodynamics(SPH)is a candidate to combine the advantages of *** is a particle method which is suitable for simulating the large deformation process,and is formulated based on continuum mechanics so that large scale problems can be handled in *** a result,SPH has also become a main way for the cutting *** some issues arise while using conventional SPH to handle solid materials,the total Lagrangian smoothed particle hydrodynamics(TLSPH)is *** instabilities would still occur during the cutting,which is a critical issue to *** paper studies the effects of TLSPH settings and cutting model parameters on the numerical instability,as well as the chip formation *** deformation,stress field and cutting forces are analyzed as *** shows that the hourglass coefficient,critical pairwise deformation and time step are three important parameters to control the stability of the simulation,and a strategy on how to adjust them is provided.

关键词： Cutting Total Lagrangian smoothed particle hydrodynamics(TLSPH) Numerical instability Chip formation

Mapping of Least ρ-Dirichlet Energy between Doubly Connected Riemann Surfaces

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

Acta Mathematica Sinica,English Series 2020年第6期36卷 663-672页

作者： Li zhang Sheng jin huO hui GUO xiao Gao feng College of Mathematics and Information China West Normal UniversityNanchong 637002P.R.China Department of Mathematics Tianjin Polytechnic UniversityTianjin 300387P.R.China College of Mathematics and Statistics Shenzhen UniversityShenzhen 518060P.R.China

In this note,we consider the mappings h:X→Y between doubly connected Riemann surfaces having leastρ-Dirichlet *** a pair of doubly connected Riemann surfaces,in which X has finite conformal modulus,we establish the following principle:A mapping h in the class H2(X,Y)of strong limits of homeomorphisms in Sobolev space W1,2(X,Y)isρ-energy-minimal if and only if its Hopf-differential is analytic in X and real along?*** improves and extends the result of Iwaniec et al.(see Theorem 1.4 in[***.,209,401–453(2013)]).Furthermore,we give an application of the ***ρ-energy minimal diffeomorphism isρ-harmonic,however,we give a 1/|w|~2-harmonic diffemorphism which is not 1/|w|~2-energy minimal *** last,we investigate the necessary and sufficient conditions for the existence of 1/|w|~2-harmonic mapping from doubly connected domainΩto the circular annulus A(1,R).

关键词： ρ-Dirichlet energy Hopf-differential ρ-harmonic mapping ρ-Nitsche conjecture

Surface recrystallization of a single crystal nickel-base superalloy

在线全文

学校读者我要写书评

暂无评论

International Journal of Minerals,Metallurgy and Materials 2011年第2期18卷 197-202页

作者： Jie Meng Tao jin xiao-feng Sun Zhuang-qi hu Department of Superalloys Institutes of Metal Research Chinese Academy of Sciences Shenyang Beijing 110016 China State Key Laboratory for Advanced Metals and Materials University of Science and Technology Beijing 100083 China

The recrystallization behavior of a single crystal nickel-base superalloy was investigated by shot peening and subsequent annealing. Two kinds of recrystallization microstructures, which are intensively dependent on the annealing temperature, are shown in the nickel-base superalloy after shot peening and subsequent annealing. Surface recrystallized grains are obtained when the superalloy is annealed at solution treatment temperature. The nucleation of recrystallization originates from the dendritic core, where rapid dissolution of γ＇ particles occurs. Cellular recrystallization is observed after annealing at lower temperatures. Cellular structures induced by high diffusivity of the moving boundary and more γ＇ particles dissolution led by residual stress are developed from the surface region. Recrystallized kinetics of the shot-peened alloy annealed at 1050°C accords with the Johnson-Mehl-Avrami-Kolmogorov equation. The low Avrami exponent is caused by the inhomogeneous distribution of stored energy, the decreasing of stored energy during recovery, and the strong resistance of boundary migration by γ＇ particles.

关键词： nick-base superalloy single crystals recrystallization shot peening annealing

A consensus model for group decision making under interval type-2 fuzzy environment

在线全文

学校读者我要写书评

暂无评论

Frontiers of Information Technology & Electronic Engineering 2016年第3期17卷 237-249页

作者： xiao-xiong zhang Bing-feng GE Yue-jin TAN College of Information System and Management National University of Defense Technology Changsha 410073 China

We propose a new consensus model for group decision making(GDM) problems, using an interval type-2 fuzzy environment. In our model, experts are asked to express their preferences using linguistic terms characterized by interval type-2 fuzzy sets(IT2 FSs), because these can provide decision makers with greater freedom to express the vagueness in real-life situations. Consensus and proximity measures based on the arithmetic operations of IT2 FSs are used simultaneously to guide the decision-making process. The majority of previous studies have taken into account only the importance of the experts in the aggregation process, which may give unreasonable results. Thus, we propose a new feedback mechanism that generates different advice strategies for experts according to their levels of importance. In general, experts with a lower level of importance require a larger number of suggestions to change their initial preferences. Finally, we investigate a numerical example and execute comparable models and ours, to demonstrate the performance of our proposed model. The results indicate that the proposed model provides greater insight into the GDM process.

关键词： Group decision making (GDM) Interval type-2 fuzzy sets (IT2 FSs) Feedback mechanism