检索结果-南通市图书馆

Preparation and Characterization of Chitosan/Carboxymethylated Konjac Glucomannan Blend Films

在线全文

学校读者我要写书评

暂无评论

wuhan university Journal of Natural Sciences 2002年第1期7卷 107-112页

作者： Zheng Hua 1 , Du Yu-min 2.1. Department of Chemical engineering, wuhan {2. of technology, wuhan 430070, hubei, china 2. college of Chemistry and Molecular Sciences, wuhan {2., wuhan 430072. hubei, china wuhan university of {2. Department of Chemical Engineering Wuhan Hubei China (GRID:grid.162110.5) (ISNI:***) wuhan university College of Chemistry and Molecular Sciences Wuhan Hubei China (GRID:grid.49470.3e) (ISNI:***)

In order to improve the mechanical and water swelling properties of the chitosan (CS) film, a series of transparent films were prepared by blending 2.(weight) chitosan acetic acid solution with 1.5%(weight) carboxymethylated konjac glucomannan (CMKGM) aqueous solution according to predetermined ratio and drying at 30°C. The morphological structure, miscibility, thermal stability, mechanical properies, and swelling capacity of the blend films were studied by infrared (IR), X-ray diffraction (XRD), differential thermal analysis (DTA), scanning electron micrograph (SEM), and measurements of the mechanical properties and swelling properties. The results demonstrated that there was strong interaction and good miscibility between CS and CMKGM resulted from intermolecular hydrogen bonding and electrostatic force. The mechanical properties in dry state and wet state, thermostability, and water swelling properties of the blend films were obviously improved. The best values of the tensile strength in the dry and wet state achieved 89 MPa and 49 MPa, respectively, when the CMKGM content was 30%(weight). The CS/ CMKGM blend films provided promising biomedical applications.

关键词： Key words chitosan carboxymethylated konjac glucomannan blend films structure characterization

HCWCI/Carbon Steel Bimetal Liner by Liquid-Liquid Compound Lost Foam Casting

在线全文

学校读者我要写书评

暂无评论

Journal of Iron and Steel Research International 2012年第10期19卷 13-19页

作者： XIAO Xiao-feng1,2. YE Sheng-ping2. YIN Wei-xin3, XUE Qiong4 (1. School of mechanical engineering and Automation, {2. Textile university, {2. 430073, hubei, china 2. State Key Laboratory of Material Processing and Die and Mould technology, Huazhong university of Science and technology, {2. 430074, hubei, china 3. {2. Zhike Abrasive-Resistant Material Science and technology Development Co Ltd, {2. 430073, hubei, china 4. college of Science, {2. university of technology, {2. 430079, hubei, china) [a] School of mechanical engineering and Automation Wuhan Textile University Wuhan 430073 Hubei China [b] State Key Laboratory of Material Processing and Die and Mould technology Huazhong University of Science and Technology Wuhan 430074 Hubei China [c] wuhan Zhike Abrasive-Resistant Material Science and technology Development Co Ltd Wuhan 430073 Hubei China [d] college of Science Wuhan University of Technology Wuhan 430079 Hubei China

Impact, friction and corrosion from the grinding balls and the grinding medium during the mineral processing result in liner breakage. Liner, made from Hadfield steel or alloyed steel, could not have served in wet grinding environment for more than ten months. Composite liner, made from HCWCI (high Cr white cast iron) and carbon steel, has been developed successfully with liquid-liquid composing process based on LFC (lost foam casting). The microstructure of composite was analyzed with optical microscope, SEM (scanning electron microscope)/EDX energy-dispersive X-ray and XRD (X-ray diffraction). According to micrograph, the combination region of two metals was staggered like dogtooth, no mixtures occurred between two liquid metals, and its interface presented excellent metallurgical bonding state. The results of mechanical property test show that, the hardness of HRC, the fracture toughness, and the bending strength are more than 61, 16.5 J/cm2.and 1 600 MPa, respectively. Comparison between liners made from bimetal composite and alloyed steel has also been investigated in industrial hematite ball mill. The results of eight months test in wet grinding environment prove that the service life of bimetal composite liner is three times as long as that of one made from alloyed steel.

关键词： composite liner bimetal liquid-liquid compound composite interface lost foam casting high Cr white cast iron

Robust H-infinity fuzzy control for uncertain Markovian jump nonlinear singular systems with wiener process

在线全文

学校读者我要写书评

暂无评论

控制理论与应用（英文版） 2010年第2期8卷 205-210页

作者： Aiqing ZHANG 1 , Huajing FANG 2.(1.college of Mathematics and Computer Science, Jianghan university, {2. hubei 430056, china 2.Department of Control Science and engineering, Huazhong university of Science and technology, {2. hubei 430074, china) college of Mathematics and Computer Science Jianghan University Wuhan Hubei China Department of Control Science and engineering Huazhong University of Science and Technology Wuhan Hubei China

This paper deals with the problems of robust stochastic stabilization and H-infinity control for Markovian jump nonlinear singular systems with Wiener process via a fuzzy-control approach. The Takagi-Sugeno (T-S) fuzzy model is employed to represent a nonlinear singular system. The purpose of the robust stochastic stabilization problem is to design a state feedback fuzzy controller such that the closed-loop fuzzy system is robustly stochastically stable for all admissible uncertainties. In the robust H-infinity control problem, in addition to the stochastic stability requirement, a prescribed performance is required to be achieved. Linear matrix inequality (LMI) sufficient conditions are developed to solve these problems, respectively. The expressions of desired state feedback fuzzy controllers are given. Finally, a numerical simulation is given to illustrate the effectiveness of the proposed method.

关键词： Fuzzy control H-infinity control Singular systems Stochastic stability Linear matrix inequality (LMI)

Kinetics analysis of volume phase transition of intelligent neutral thermo-sensitive hydrogels

在线全文

学校读者我要写书评

暂无评论

Science china(Physics,Mechanics & Astronomy) 2008年第5期51卷 532-540页

作者： WANG XiaoGui1 & LI YiQuan2.1 college of mechanical {2.,Zhejiang university of technology,Hangzhou 310032.china 2.School of mechanical & Electronic {2.,Changchun university of Science and technology,Changchun 13002.,china 1. college of mechanical {2. Zhejiang University of Technology Hangzhou 310032 China 2. School of mechanical & Electronic engineering Changchun University of Science and Technology Changchun 130022 China

In this work,utilizing the first law of thermodynamics and the Flory mean-field theory,the kinetic deformation studies concerning the volume phase transition of the neutral thermo-sensitive hydrogels were performed *** hydrogel was assumed as a biphasic mixture medium in the framework of the continuum mixture *** the energy conservation of the thermodynamics system of the hydrogel,the governing equations for the kinetics of the nonlinear large deforma-tion were *** explicit analytical expressions of the effective stress tensor and the chemical potential of the fluid of the thermo-sensitive hydrogel PNIPA were also obtained from the Helmholtz free energy,which can model the steady-static volume phase transition quantitatively.

关键词： thermo-sensitive hydrogel volume phase transition effective stress energy conservation

Sensitive Determination of DNA by RLS Enhancement of Metal Ions

在线全文

学校读者我要写书评

暂无评论

wuhan university Journal of Natural Sciences 2004年第2期9卷 234-238页

作者： Huang Jian-ping 1,2. Chen Fang 1, Ai Xin-ping 1, He Zhi-ke 1 1. college of Chemistry and Molecular Sciences, wuhan {2., wuhan 430072. hubei, china 2. Department of Environmental engineering, hubei Agricultural college, Jingzhou 43402., hubei, china wuhan university College of Chemistry and Molecular Sciences Wuhan Hubei China (GRID:grid.49470.3e) (ISNI:***) hubei Agricultural college Department of Environmental Engineering Jingzhou Hubei China (GRID:grid.49470.3e) wuhan university College of Chemistry and Molecular Sciences Wuhan Hubei China (GRID:grid.49470.3e) (ISNI:***)

The interactions between metal ions and DNA have been studied by the resonance light scattering (RLS) spectra. In the acidic condition, the RLS signals of metal ions, especially the transition metal ions in group IB and IIB, were increased by DNA. And it is found that the enhancement of RLS signals is linear to the concentration of DNA, so the RLS method for DNA determination was proposed in the presence of Cu2.. On the optimum conditions, the linear range and the detect limit of ctDNA is 4×10?8–4×10?6 g· mL?1 and 1. 13×10?8 g·mL?1, respectively. The proposed method is successfully applied to determine the extracted plasmid DNA ofBacillus subtilis DB104. Key words resonance light scattering - DNA - metal ions CLC number O 657.3 Foundation item: Supported by National Natural Science Foundation of china (2.2.502.) and the National Key Basic Research and Development Program (973 Program 2.02.B2.1800).Biography: Huang Jian-ping(1964-), male, Associate professor, research direction: bioanalysis.

关键词： resonance light scattering DNA metal ions

Determination of the Thermal Expansion Coefficient of Concrete at Early Ages by Using Temperature-stress Testing Machine

在线全文

学校读者我要写书评

暂无评论

Journal of wuhan university of {2.(Materials Science) 2006年第4期21卷 146-149页

作者：霍凯成 hubei Key Laboratory of Roadway Bridge & Structure engineering Wuhan University of TechnologyWuhan 430070China

By using the uptodate temperatuer-stress testing machine, the thermal expansion coefficient of concrete at early ages was studied and indicative conclusions were achieved ： temperature rising due to hydration heat is not directly correlated with cracking, but the temperature and stress evolation process should be taken into consideration in the same time. Proper chemical admixtures and mineral cornpasitions can improve the mechanical properties of concrete such as thermal expansion coefficient, which is very indicative in practice.

关键词： concrete coefficient of thermal expansion temperature-stress test

Mechanism of Strength Loss of No-bake Phosphate Bonded Sand Mold/Core

在线全文

学校读者我要写书评

暂无评论

Journal of wuhan university of {2.(Materials Science) 2009年第1期24卷 5-8页

作者：张友寿 School of Automobile engineering Wuhan University of Technology School of mechanical engineering Hubei University of Technology

The strength loss mechanism of the phosphate bonded sand mold/core was studied. The morphology and composition of phosphate membrane on the surface of sands was analyzed with electron probe X-ray microanalyzer. Results show that magnesium causes cracks in cured phosphate membrane and results in the decrease of sand molds/cores strength. However, the addition of magne-sium significantly enhanced hygroscopy resistance of phosphate membrane. In addition, the phosphate binder added with the magnesium modifier has more rapid hardening reaction speed compared that without or with low magnesium binder. It can be concluded that the phosphate binder with the addition of magnesium modifier is favorably used in high humid and cold circumstance.

关键词： phosphate mechanism of strength loss crack hygroscopy resistance

Second-order consensus in networks of dynamic agents with communication time-delays

在线全文

学校读者我要写书评

暂无评论

Journal of Systems engineering and Electronics 2010年第1期21卷 88-94页

作者： Bo Yang1,2. Huajing Fang3, and Hua Wang4 1. School of Navigation, wuhan university of {2., wuhan 430063, P. R. china 2. wuhan Second Ship Design and Research Institute, wuhan 430064, P. R. china 3. Department of Control Science and engineering, Huazhong university of Science and {2., wuhan 430074, P. R. china 4. Department of Aerospace and mechanical engineering, Boston university, Boston MA02.15, USA School of Navigation Wuhan University of Technology Wuhan 430063 P. R. China wuhan Second Ship Design and Research Institute Wuhan 430064 E R. China Department of Control Science and engineering Huazhong University of Science and Technology Wuhan 430074 P. R. China Department of Aerospace and mechanical engineering Boston University Boston MA02215 USA

This paper proposes second-order consensus protocols with time-delays and gives the measure of the robustness of the protocols to the time-delay existing in the network of agents with second-order dynamics. By employing a frequency domain method, it is proven that the information states and their time derivatives of all the agents in the network achieve consensus asymptotically, respectively, for appropriate communication timedelay if the topology of weighted network is connected. Particularly, a tight upper bound on the communication time-delay that can be tolerated in the dynamic network is found. The consensus protocols are distributed in the sense that each agent only needs information from its neighboring agents, which reduces the complexity of connections between neighboring agents significantly. Numerical simulation results are provided to demonstrate the effectiveness and the sharpness of the theoretical results for second-order consensus in networks in the presence of communication time-delays.

关键词： second-order consensus protocols dynamic networks algebraic graph theory frequency domain analysis com-munication constraints.

METHOD TO SOLVE ELASTIC CONJUGATE SURFACES IN MULTI-TEETH MESHING

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of mechanical engineering 2002年第4期15卷 348-352页

作者： Yi ChuanyunSchool of mechanical Science and engineering, Huazhong {2. of Science and technology,wuhan 430074, china School of mechanical Science and engineering Huazhong University of Science and Technology Wuhan 430074

A method to solve the elastic conjugate surfaces in multi-teeth meshing ispresented. In mechanical manufacturing and design, there exist a lot of problems relating toconjugate surfaces, such as three-dimensional engagement, steel rolling and workpiece machining,which cause great effects on the quality of machining and performances of transmission. This methoddescribes relation between conjugate motion and elastic deformation in the process of mesh-in andmesh-out, and can be used to determine the profile of gear tooth by a certain given load sharing.

关键词： multi-teeth meshing elastic conjugate surfaces