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SUBSTRUCTURE PRECONDITIONERS FOR NONCONFORMING PLATE ELEMENTS

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Journal of Computational Mathematics 1998年第4期16卷 289-304页

作者： Shi, ZC Xie, zh Chinese Acad Sci ICMSEC State Key Lab Sci & Engn Comp Beijing 100080 Peoples R China Chinese Acad Sci Inst Atmospher Phys LASG Beijing 100080 Peoples R China

In this paper, we consider the problem of solving finite element equations of biharmonic Dirichlet problems. We divide the given domain into non-overlapping subdomains, construct a preconditioner for Morley element by substructuring on the basis of a function decomposition for discrete biharmonic functions. The function decomposition is introduced by partitioning these finite element functions into the low and high frequency components through the intergrid transfer operators between coarse mesh and fine mesh, and the conforming interpolation operators. The method leads to a preconditioned system with the condition number bounded by C(1 + log(2) H/h) in the case with interior cross points, and by C in the case without interior cross points, where H is the subdomain size and h is the mesh size. These techniques are applicable to other nonconforming elements and are well suited to a parallel computation.

关键词： substructure preconditioner biharmonic equation nonconforming plate element

MULTIGRID METHODS FOR MORLEY ELEMENT ON NONNESTED MESHES

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Journal of Computational Mathematics 1998年第5期16卷 385-394页

作者： Shi, ZC Xie, zh Chinese Acad Sci ICMSEC State Key Lab Sci & Engn Comp Beijing 100080 Peoples R China Chinese Acad Sci Inst Atmospher Phys LASG Beijing 100080 Peoples R China

In this paper, we consider some multigrid algorithms for the biharmonic problem discretized by Morley element on nonnested meshes. Through taking the averages of the nodal variables we construct an intergrid transfer operator that satisfies a certain stable approximation property. The so-called regularity-approximation assumption is then established. Optimal convergence properties of the W-cycle and a uniform condition number estimate for the variable V-cycle preconditioner are presented. This technique is applicable to other nonconforming plate elements.

关键词： multigrid method Morley element nonnested meshes

磷化电流密度对A286合金电化学磷化膜组织结构和结合强度的影响

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材料保护 2024年第2期57卷 128-133,147页

作者：胡勇周昊杜孟飞曾宇乔张旭海方峰东南大学材料与科学工程学院江苏南京211189 宝钢金属有限公司上海200940

A286合金表面易钝化,通过传统化学磷化方法在其表面难以沉积磷化膜,而电化学磷化可避免钝化膜对磷化反应的抑制作用。因此,研究磷化电流密度对磷化膜组织结构和性能的影响规律很有必要。通过电化学磷化首次在A286合金表面形成了致密、... 详细信息

A286合金表面易钝化,通过传统化学磷化方法在其表面难以沉积磷化膜,而电化学磷化可避免钝化膜对磷化反应的抑制作用。因此,研究磷化电流密度对磷化膜组织结构和性能的影响规律很有必要。通过电化学磷化首次在A286合金表面形成了致密、高膜基结合力的磷化膜。利用电化学工作站对不同电流密度下磷化过程中电位-时间(ϕ-t)曲线进行测绘,研究电化学磷化膜生长过程的特点;使用扫描电子显微镜(SEM)观察磷化膜的显微组织形貌;使用能谱仪(EDS)分析磷化膜中不同区域的化学成分;使用X射线衍射仪(XRD)研究磷化膜的物相结构;使用划痕仪测定磷化膜与基体的结合力。结果显示:A286合金电化学磷化膜的沉积模式为逐层生长-堆叠的形式。低电流密度下,磷化膜为单一的Hopeite相,组织结构粗大、疏松,膜基结合力约为6 N。随着磷化电流密度的增加,磷化膜逐渐转变为Zn+Hopeite复相,组织结构细化、致密,膜基结合力提高。当阴极电流密度为160 mA/cm^(2)时,膜基结合力高于60 N。综合可知,磷化电流密度的增加有利于电化学磷化膜的致密化,有利于膜基结合力和耐磨性的提高。

关键词：电化学磷化膜电流密度 A286 合金组织结构膜基结合力

Laser and Fluorescence Properties of Organic Dye DCM Doped Sol-Gel-Derived Solid-State Materials

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Journal of Materials Science & Technology 1999年第6期15卷 563-566页

作者： zh.ng, QY Jiang, zh Tongji Univ Pohl Inst Solid State Phys Shanghai 200092 Peoples R China Chinese Acad Sci Shanghai Inst Opt & Fine Mech Shanghai 201800 Peoples R China

Two kinds of new Ormosil xerogels derived from GPTMS (3-glycidyl propyl trimethoxisilane) and TEOS (tetraethoxysilane) or GPTMS and Ti(OBu)4 (tetrabutoxytitanate) were synthesized viathe sol-gel method as dye laser host. Their optical properties, microstructure characteristics and sudece laser damage thresholds have been reported. The effects of dye matrix combination on the fluorescence emission, slope efficiency, photostability and tunable bandwidth were *** oscillation was easily achieved near 620 nm with a slope efficiency of 29% from DCM dopedSiO2-Ormosil pumped by a frequency-doubled radiation from a Q-switched Nd:YAG laser. The laser wavelength was tunable over 59 nm, and the laser output energy had only a 10% reduction after 2.5× 104 pulses at a pump repetition rate of 1Hz and a pump intensity of 1

关键词： GPTMS DCM EtOH

Magneto-rheological elastomer (MRE) based composite structures for micro-vibration control

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Earthquake Engineering and Engineering Vibration 2010年第3期9卷 345-356页

作者： YQ Ni ZG Ying zh.Chen Department of Civil and Structural Engineering The Hong Kong Polytechnic University Hung Horn Kowloon Hong Kong China Department of Mechanics Zhejiang University Hangzhou 310027 China

Magneto-rheological elastomers （MILEs） are used to construct composite structures for micro-vibration control of equipment under stochastic support-motion excitations. The dynamic behavior of MREs as a smart viscoelastic material is characterized by a complex modulus dependent on vibration frequency and controllable by external magnetic fields. Frequency-domain solution methods for stochastic micro-vibration response analysis of the MRE-based structural systems are developed to derive the system frequency-response function matrices and the expressions of the velocity response spectrum. With these equations, the root-mean-square （RMS） velocity responses in terms of the one-third octave frequency band spectrum can be calculated. Further, the optimization problem of the complex moduli of the MRE cores is defined by minimizing the velocity response spectra and the RMS velocity responses through altering the applied magnetic fields. Simulation results illustrate the influences of MRE parameters on the RMS velocity responses and the high response reduction capacities of the MRE-based structures. In addition, the developed frequency-domain analysis methods are applicable to sandwich beam structures with arbitrary cores characterized by complex shear moduli under stochastic excitations described by power spectral density functions, and are valid for a wide frequency range.

关键词： magneto-rheological elastomer (MRE) micro-vibration control equipment composite structure sandwich beam stochastic excitation

Investigation of the Surface Properties of Vinyl Ethers – Sodium 2-Acrylamido-2-Methylpropanesulfonate Copolymers

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Advances in Materials Physics and Chemistry 2012年第4期2卷 177-180页

作者： S. Kh. Khussain E. M. Shaikhutdinov N. zh. Seitkaliyeva A. zh. zh.nisova Department of applied chemistry Kazakh National Technical University named after Kanysh Satpaev Almaty Kazakhstan

The surface properties of water soluble copolymers vinyl ethers of monoethanolamine and ethylene glycol with sodium 2-acrylamido-2-methyl-propanesulfonate were investigated by studying adsorption at the aqueous solution – air interface. It is found that copolymers have considerably higher surface activity in comparison with poly- sodium 2-acrylamido-2-methyl-propanesulfonate.

关键词： Surface Active Copolymers Adsorption Interface Standard Free Energy of Adsorption

Solid liquid Mixed Casting of Al-Si Alloy

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Journal of Central South University 2000年第3期12卷 133-135页

作者： Chen, zh.Kang, ZT Cent S Univ Technol Dept Mat Sci & Engn Changsha 410083 Peoples R China

The paper presents a novel material preparation technology—Solid liquid mixed casting technology. In the technology, large amounts of homogeneous alloy powder or heterogenous powder with perfect wettability are added into the superheated melt. After strong agitation, the mixed melt can be cast or hot processed. Applying solid liquid mixed casting, three kinds of Al Si alloys were investigated. The results show that, when the mass of powder accession to alloy melt is about 1, the mean size of primary Si in hyper eutectic alloy can be controlled at less than 5 μm; and the mean grain size of α phase in hypo eutectic alloy is less than 10 μm. This technology has the advantage of preparing material with very fine microstructure by fairly simple casting process, and may be a new practicable and valuable metal preparation technology.

关键词： solid liquid mixed casting powder melt Document code:A

A Simple and Novel Ipso-Bromination of 1-Bromomethyl-4-t-butyl-2,6-dimethylbenzene

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Chinese Chemical Letters 1997年第4期8卷 271-274页

作者： zh.ng, WC Yu, zh CHINESE ACAD SCI INST CHEMBEIJING 100080PEOPLES R CHINA

A novel ipso electrophlic substitution of 1-bromomethyl-4-t-butyl-2,6-dimethylbenzene 1 with nitric acid in alcohol, which gives ipso-bromination product of 1-bromo-4-t-butyl-2,6-dimethylbenzene 2, is described and a ... 详细信息

关键词： NITRATION

基于卡诺模型的社区乳腺癌患者健康服务需求分析

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International Journal of Nursing Sciences 2024年第2期11卷 171-178,I0001页

作者：章毛毛张柳柳智晓旭程芳姚宇锋邓荣刘春丽王燕 Jiangsu Cancer Hospital Jiangsu Institute of Cancer ResearchNanjing Medical University Affiliated Cancer HospitalNanjingChina

目的为乳腺癌患者提供满意的医疗服务,可有效减轻患者的负担和医疗资源压力。本研究的目的是利用卡诺模型探讨社区乳腺癌患者的健康服务需求。方法2023年1月—3月对某三级肿瘤医院出院的乳腺癌患者进行横断面调查。患者填写了基于卡诺... 详细信息

目的为乳腺癌患者提供满意的医疗服务,可有效减轻患者的负担和医疗资源压力。本研究的目的是利用卡诺模型探讨社区乳腺癌患者的健康服务需求。方法2023年1月—3月对某三级肿瘤医院出院的乳腺癌患者进行横断面调查。患者填写了基于卡诺模型自行设计的健康服务需求调查问卷,同时也提供了社会人口学信息。调查问卷中包括30项健康服务内容,基于卡诺模型对这些项目的属性进行分类和优先级排序。结果共回收有效问卷296份。对30项医疗服务的需求属性进行评价的结果显示,30项服务中有1项被归类为“必备型属性”(身体形象管理),13项被归类为“期望型属性”(侧重于医疗保障支持、健康管理和健康咨询),3项被归类为“魅力型属性”(侧重于沟通需求和远程保健服务),11项被归类为“无差异型属性”(主要集中在社会心理服务领域)。结论社区乳腺癌患者对不同健康服务项目的需求程度不同。医务工作者应根据患者需求确定有效的健康服务策略,优先提供必备型和期望型属性的服务,努力提供魅力型属性服务,以提高社区乳腺癌患者的生活质量。

关键词：乳腺肿瘤癌症患者卫生保健提供需求分析卫生人员卡诺模型