检索结果-南通市图书馆

Double stabilizations and convergence analysis of a second-order linear numerical scheme for the nonlocal Cahn-Hilliard equation

在线全文

学校读者我要写书评

暂无评论

Science China Mathematics 2024年第1期67卷 187-210页

作者： Xiao Li Zhonghua Qiao cheng Wang Department of Applied Mathematics The Hong Kong Polytechnic UniversityHong KongChina Department of Mathematics The University of MassachusettsNorth DartmouthMA 02747USA

In this paper,we study a second-order accurate and linear numerical scheme for the nonlocal CahnHilliard *** scheme is established by combining a modified Crank-Nicolson approximation and the Adams-Bashforth extrapolation for the temporal discretization,and by applying the Fourier spectral collocation to the spatial *** addition,two stabilization terms in different forms are added for the sake of the numerical *** conduct a complete convergence analysis by using the higher-order consistency estimate for the numerical scheme,combined with the rough error estimate and the refined *** regarding the numerical solution as a small perturbation of the exact solution,we are able to justify the discrete?^(∞)bound of the numerical solution,as a result of the rough error ***,the refined error estimate is derived to obtain the optimal rate of convergence,following the established?∞bound of the numerical ***,the energy stability is also rigorously proved with respect to a modified *** proposed scheme can be viewed as the generalization of the second-order scheme presented in an earlier work,and the energy stability estimate has greatly improved the corresponding result therein.

关键词： nonlocal Cahn-Hilliard equation second-order stabilized scheme higher-order consistency analysis rough and refined error estimate

在线全文

学校读者我要写书评

暂无评论

基于用户需要与功能融合的已有产品创新设计

机床与液压 2022年第20期50卷 106-112页

作者：于志刚成思源杨雪荣广东工业大学机电工程学院广东广州510006

针对已有产品的创新设计,为充分考虑不同类型的用户需要信息,利用可拓创新方法对其进行形式化和流程化研究,提出基于用户需要与功能融合的已有产品创新设计方法。建立用户需要事元,并与已有产品功能事元进行比较,若类型一致,则通过功能... 详细信息

针对已有产品的创新设计,为充分考虑不同类型的用户需要信息,利用可拓创新方法对其进行形式化和流程化研究,提出基于用户需要与功能融合的已有产品创新设计方法。建立用户需要事元,并与已有产品功能事元进行比较,若类型一致,则通过功能分析对原系统进行分析,找到问题功能并利用基元理论和可拓变换改进原系统功能结构模型;若类型不同,通过用户需要事元与功能事元的映射关系获得功能动作表现的物元;根据功能事元和结构关系元的映射关系获得结构关系元的特征和量值,建立新功能系统模型;将两类模型进行功能融合并得到新产品的功能配置及设计方案。通过对已有光伏电池板清洁设备进行创新设计,验证了该方法的可行性与有效性。

关键词：创新设计用户需要与功能融合基元理论映射关系

Manipulating the Phase Transition Behavior of Dual Temperature-Responsive Block Copolymers by Adjusting Composition and Sequence

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Polymer Science 2024年第2期42卷 176-187,I0006页

作者： Zhi Zou Xiang Xu Hai-Tao Zhao Jian-Nan cheng Wei-Wei He Li-Fen Zhang Zhen-Ping cheng Suzhou key Laboratory of Macromolecular Design and Precision Synthesis Jiangsu Key Laboratory of Advanced Functional Polymer Design and ApplicationState and Local Joint Engineering Laboratory for Novel Functional Polymeric MaterialsCollege of ChemistryChemical Engineering and Materials ScienceSoochow UniversitySuzhou215123China State Key Laboratory of Radiation Medicine and Protection School for Radiological and Interdisciplinary Sciences(RAD-X)and Collaborative Innovation Center of Radiation Medicine of JiangsuSoochow UniversitySuzhou215123China

Temperature-responsive polymers have garnered significant attention due to their ability to respond to external *** this work,dual temperature-responsive block copolymers are synthesized via reversible addition-fragmentation chain transfer polymerization(RAFT)polymerization utilizing zwitterionic monomer methacryloyl ethyl sulfobetaine(SBMA) and N-isopropyl acrylamide(NIPAAm) as *** thermal responsive behaviors can be easily modulated by incorporating additional hydrophobic monomer benzyl acrylate(BN) or hydrophilic monomer acrylic acid(AA),adjusting concentration or pH,or varying the degree of polymerization of the block chain *** cloud points of the copolymers are determined by UV-Vis spectrophotometry,and these copolymers exhibit both controlled upper and lower critical solu bility temperatures(LCST and UCST) in aqueous *** study analyzes and summarizes the influencing factors of dual temperature responsive block copolymers by exploring the effects of various conditions on the phase transition temperature of temperature-sensitive polymers to explore the relationship between their properties and environment and structure to make them more selective in terms of temperature application range and regulation *** is very interesting that the introduction of poly-acrylic acid(PAA) segments in the middle of di-block copolymer PSBMA_(55)-b-PNIPAAm_(80) to form PSBMA_(55)-b-PAA_(x)-b-PNIPAAm_(80) results in a reversal of temperature-responsive behaviors from 'U'(LCST UCST) type,while the copolymer PSBMA_(55)-b-P(NIPAAm_(80)-co-AA_(x)) *** work provides a clue for tuning the phase transition behavior of polymers for manufacture of extreme smart materials.

关键词： Temperature responsive polymers High critical solubility temperature(UCST) Low critical solubility temperature(LCST) Block copolymers

Reconstruction of biomimetic ionic channels within covalent organic frameworks for ultrafast and selective uranyl capture

在线全文

学校读者我要写书评

暂无评论

Science China Chemistry 2024年第10期67卷 3423-3431页

作者： cheng-Rong Zhang Xiao-Juan Chen cheng-Peng Niu cheng Meng Shun-Mo Yi Xin Liu Jia-Xin Qi Qiu-Xia Luo Ru-Ping Liang Jian-Ding Qiu State Key Laboratory of Nuclear Resources and Environment East China University of TechnologyNanchang 330013China College of Chemistry and Chemical Engineering Nanchang UniversityNanchang 330031China

The efficient extraction of uranium,as the primary component of nuclear energy,holds significant *** inspiration from the charge interaction observed in biological ion channels,we encapsulated negatively charged polystyrene sulfonate(PSS)or sodium polystyrene carboxylate(PVBA)into the nanochannels of amidoxime functionalized covalent organic framework(COF-AO)in-situ to alter the cavity environment of *** synthesized COF-AO-PSS and COF-AO-PVBA are used for ultra-fast and highly selective uranium *** negatively charged PSS/PVBA was confined in the COF-AO channel providing the driving force for uranium transport and blocking other ions,thus creating a highly selective“uranium highway”.Additionally,introducing sulfonate groups or carboxyl groups into COF-AO offers supplementary coordination environments and weak interactions with *** to charge-assisted migration and various interaction mechanisms,both COF-AO-PSS and COF-AO-PVBA exhibit faster adsorption kinetics and higher selectivity compared to COF-AO *** adsorption capacities are 3.8 times and 2.4 times that of COF-AO alone respectively which highlights the necessity for constructing biomimetic ion channels in uranium adsorption *** work presents a bionic adsorbent based on covalent organic frameworks(COFs)for the first time,overcoming environmental and equipment limitations associated with traditional photocatalysis and electrocatalysis methods for uranium capture,opening up new avenues for designing multifunctional materials that mimic biological systems.

关键词： covalent organic frameworks Uranium biomimetic ion-channels adsorption

Study on site selection planning of urban electric vehicle charging station

在线全文

学校读者我要写书评

暂无评论

High Technology Letters 2024年第1期30卷 75-84页

作者：刘娜 cheng Jiaxin DUAN Yukai School of Business Shanghai Dianji UniversityShanghai201306 P.R.China

The large-scale development of electric vehicles(EVs)requires numerous charging stations to serve them,and the charging stations should be reasonably laid out and planned according to the charging demand of electric *** the costs of both operators and users,a site selection model for optimal layout planning of charging stations is constructed,and a queuing theory approach is used to determine the charging pile configuration to meet the charging demand in the planning *** solve the difficulties of particle swarm global optimization search,the improved random drift particle swarm optimization(IRDPSO)and Voronoi diagram are used to jointly solve for the optimal layout of electric *** final arithmetic analysis verifies the feasibility and practicality of the model and algorithm,and the results show that the total social cost is minimized when the charging station is 9,the location of the charging station is close to the center of gravity and the layout is reasonable.

关键词： charging station electric vehicle(EV) improved random drift particle swarm optimization(IRDPSO) optimal planning

在线全文

学校读者我要写书评

暂无评论

基于逆向建模元素的个体化医疗器械设计

现代制造工程 2018年第10期 130-135页

作者：李明宇丛海宸成思源姜自伟广东工业大学机电工程学院广州510006 广东省创新方法与决策管理系统重点实验室广州510006 广州中医药大学第一附属医院广州510504

逆向工程中的参数化建模方法是逆向建模研究的重要方向之一。通过对目前广泛应用的逆向参数化建模方法进行分析,提出了基于逆向建模元素的产品模型设计,将功能分析和形态分析相结合,用于提取建模元素,建立基于功能-形态-参数模型的建模... 详细信息

逆向工程中的参数化建模方法是逆向建模研究的重要方向之一。通过对目前广泛应用的逆向参数化建模方法进行分析,提出了基于逆向建模元素的产品模型设计,将功能分析和形态分析相结合,用于提取建模元素,建立基于功能-形态-参数模型的建模方法,并详细介绍了这种建模方法的优势及其一般流程。同时以逆向参数化建模软件Geomagic Design X为平台,通过典型医疗器械实例的参数化建模验证了该建模方法的优势,为个体化医疗器械逆向建模提供了一种更加有效的建模方法。

关键词：逆向工程医疗器械功能分析形态分析建模元素

基于9,10-二羟基硬脂酸的锂基润滑脂制备及流变学性能研究

在线全文

学校读者我要写书评

暂无评论

重庆理工大学学报（自然科学） 2018年第10期32卷 121-126页

作者：成思远郭小川何燕刘万杰中国人民解放军陆军勤务学院军事油料应用与管理工程系重庆401331

采用自制9,10-二羟基硬脂酸作为稠化剂制备了锂基润滑脂,与12-羟基硬脂酸锂制备的传统锂基润滑脂进行了流变学性能对比,并从分子结构角度对两者的性能差异进行了分析。结果表明:与传统锂基润滑脂相比,9,10-二羟基硬脂酸制备的锂基润滑... 详细信息

采用自制9,10-二羟基硬脂酸作为稠化剂制备了锂基润滑脂,与12-羟基硬脂酸锂制备的传统锂基润滑脂进行了流变学性能对比,并从分子结构角度对两者的性能差异进行了分析。结果表明:与传统锂基润滑脂相比,9,10-二羟基硬脂酸制备的锂基润滑脂受外力剪切时更容易发生形态转变和流动,但受剪切后结构恢复能力更强。

关键词： 9,10-二羟基硬脂酸 12-羟基硬脂酸锂基润滑脂流变学性能

A Reliable Iteration Algorithm for One-Bit Compressive Sensing on the Unit Sphere

在线全文

学校读者我要写书评

暂无评论

Acta Mathematicae Applicatae Sinica 2024年第3期40卷 801-822页

作者： Yan-cheng LU Ning BI An-hua WAN School of Mathematics Sun Yat-sen UniversityGuangzhou 510275China

The one-bit compressed sensing problem is of fundamental importance in many areas,such as wireless communication,statistics,and so ***,the optimization of one-bit problem coustrained on the unit sphere lacks an algorithm with rigorous mathematical proof of convergence and *** this paper,an iteration algorithm is established based on difference-of-convex algorithm for the one-bit compressed sensing problem constrained on the unit sphere,with iterating formula■,where C is the convex cone generated by the one-bit measurements andη_(1)>η_(2)>1/*** new algorithm is proved to converge as long as the initial point is on the unit sphere and accords with the measurements,and the convergence to the global minimum point of the l_(1)norm is discussed.

关键词： one-bit compressed sensing difference of convex algorithm iteration algorithm ■1-minimization

Force-position collaborative optimization of rope-driven snake manipulator for capturing non-cooperative space targets

在线全文

学校读者我要写书评

暂无评论

CHINESE JOURNAL OF AERONAUTICS 2024年第9期37卷 369-384页

作者： Li, Xiaofeng Tian, Jian Wei, cheng Cao, Xibin Harbin Inst Technol Sch Astronaut Harbin 150001 Peoples R China China Acad Space Technol Beijing Inst Spacecraft Syst Engn Beijing 100094 Peoples R China

With the rapid development of space activities, non-cooperative space targets increase swiftly, such as failed satellites and upper stages, threating normal spacecrafts seriously. As there are some problems in the capture process, such as excessive collision and fast tumbling of targets, manipulator with redundant Degrees of Freedom (DOFs) can be used to improve the compliance and therefore solve these problems. The Rope-Driven Snake Manipulator (RDSM) is a combination of hyper-redundant DOFs and better compliance, and therefore it is suitable for capturing mission. In this paper, a snake manipulator mechanism is designed, and the complete kinematic model and system dynamic model considering RDSM, target and contact is established. Then, to obtain the configuration of joint with hyper-redundant DOFs, an improved motion dexterity index is proposed as the joint motion optimization target. Besides, the force-position collaborative optimization index is designed to adjust active stiffness, and the impedance control method based on the modified index is used to capture the space target. Finally, the proposed force-position collaborative optimization method is verified by virtual prototype co-simulation. The results demonstrate that based on the proposed method, the collision force is reduced by about 25% compared to normal impedance control, showing higher safety. (c) 2024 Production and hosting by Elsevier Ltd. on behalf of Chinese Society of Aeronautics and Astronautics. This is an open access article under the CC BY-NC-ND license (http://***/ licenses/by-nc-nd/4.0/).

关键词： Capturing non-cooperative space targets Rope-driven snake manipu- lator Force-position collaborative optimization Redundant degrees of free- dom Active stiffness adjustment DUAL-ARM SPACE IMPEDANCE CONTROL ROBOT DEXTERITY INDEX