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Electron Beam Curing of Advanced Composites

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Journal of Materials Science & Technology 2000年第6期16卷 627-630页

作者： gang SUI, Weihong zhong Dep. of Materials Sci. and Eng. Beijing Univ. of Aeron. and Astron. Beijing 100083 China

The fundamental concept of electron beam method and the application in cure of composites are elaborated in this paper. The components of electron beam curing system are introduced. The mechanisms of interaction between electron beam and polymer matrix composites are presented. Recent studies reported including work of authors themselves on electron beam curing of composites are also discussed. Moreover, the authors believe that it is necessary to do the basic research about understanding how electron beam affects cured network and the mechanical/physical properties of the composites, for establishing a quantitative or semi-quantitative formulation.

关键词： Electron Beam Curing of Advanced Composites EB

Synchronized Firing in Coupled Inhomogeneous Excitable Neurons

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Communications in Theoretical Physics 2002年第10期38卷 415-420页

作者： ZHENG Zhi-gang WANG Fu-zhong Department of Physics Beijing Normal University Beijing 100875 China Department of Physics Jinzhou Teachers College Jinzhou 121003 Liaoning Province China Department of Physics Jinzhou Teachers College Jinzhou 121003 Liaoning Province China

We study the firing synchronization behavior of the inhomogeneous excitable media. Phase synchronizationof neuron firings is observed with increasing the coupling, while the phases of neurons are different (out-of-phase synchronization). We found the synchronization of bursts can be greatly enhanced by applying an external forcing (in-phasesynchronization). The external forcing can be either a periodic or just homogeneous thermal noise. The mechanismresponsible for this enhancement is *** numbers: 05.45.-a, 87.10.

关键词： excitable media, phase synchronization, FitzHugh-Nagumo model

Hot tearing susceptibility of Fe-20.96Cr-2.13Ni-0.15N-4.76Mn-0.01Mo duplex stainless steel

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Journal of Iron and Steel Research International 2017年第4期24卷 421-425页

作者： Zhi-qiang Wei Xiang-ru Chen Hong-gang zhong Qi-jie Zhai gang Wang State Key Laboratory of Advanced Special Steel&Shanghai Key Laboratory of Advanced Ferrometallurgy&School of Materials Science and Engineering Shanghai UniversityShanghai 200072China

The hot tearing susceptibility of a Fe-20.96Cr-2.13Ni-0.15N-4.76Mn-0.01 Mo duplex stainless steel was investigated using method of constrained solidification shrinkage in one *** apparatus for realtime measuring the contraction stress and temperature during solidification was developed,which can achieve the in-situ observation of melting and solidification and avoid the large temperature gradient of casting under the condition of *** results show that the contraction stress increases significantly when the core temperature of casting reaches the liquidus *** contraction stress is released when the core temperature of casting reaches 1456°*** this temperature,the hot tearing susceptibility of duplex stainless steel is the *** decreasing the core temperature to 1363°C,the slope of contraction stress increases,which is related to the ferrite-to-austenite transformation.

关键词： Duplex stainless steel Hot tearing Solidification Contraction stress Core temperature

Effects of Thermal Gradients and Rotational Flows on Grain Growth in 22 t Steel Ingots

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Journal of Iron and Steel Research International 2016年第9期23卷 973-980页

作者： Zheng CHEN Qi-jie ZHAI Jie-yu ZHANG Hong-gang zhong State Key Laboratory of Advanced Special Steel School of Materials Science and EngineeringShanghai University Mechanical Department Tongling University

Heavy ingots are widely used in many industrial fields. The coarse grains formed during the process of in- got solidification influence the properties and fracture behaviors of the final products. The coarse grain growth was simulated under different thermal gradients. A 30Cr2Ni4MoV steel ingot was melted in a cubic crucible with dimen-sions of 15 cm×10 cm×23 cm, and the cooling conditions on each side of the crucible were controlled by different thermal curves. The influences of thermal gradients and rotational flows on grain growth in heavy steel ingots were then investigated both numerically and experimentally. The results showed that when the amplitude of the rotation angle was 60°, the metal was solidified under a reciprocating horizontal rotational condition when the angular velocity was 10 （°）/s or 20 （°）/s. As the thermal gradient increased, the lengths of the primary columnar grains in- creased, and the diameters of equiaxed grains decreased. When the direction of flow rotation was perpendicular to the direction of grain growth, the columnar grain zone was nearly eliminated, and the average diameter of equiaxed grains was 0.5 mm.

关键词： heavy ingot thermal simulation method thermal gradient rotational flow grain refinement

BaTiO_(3)-based ceramics with high energy storage density

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Rare Metals 2023年第4期42卷 1261-1273页

作者： Yang Li Ming-Yang Tang zhong-gang Zhang Qi Li Jing-Lei Li Zhuo Xu gang Liu Fei Li Electronic Materials Research Lab Key Lab of Education Ministry and State Key Laboratory for Mechanical Behavior of MaterialsSchool of Electronic Science and EngineeringXi’an Jiaotong UniversityXi’an710049China Laboratory of Micro/Nano Systems for Aerospace Ministry of EducationNorthwestern Polytechnical UniversityXi’an710072China School of Materials and Energy Southwest UniversityChongqing400715China

BaTiO_(3)ceramics are difficult to withstand high electric fields,so the energy storage density is relatively low,inhabiting their applications for miniaturized and lightweight power electronic *** address this issue,we added Sr_(0.7)Bi_(0.2)TiO_(3)(SBT)into BaTiO_(3)(BT)to destroy the long-range ferroelectric ***^(2+)was introduced into BT-SBT in the form of CaTiO_(3)(CT),which has the effect of inhibiting the movement of A-site defects to reduce dielectric loss and refining the grains to increase the breakdown field *** addition,we have increased the density and grain uniformity of ceramics by repeated rolling of the green samples through the viscous polymer processing(VPP),to further increase the breakdown electric *** BT-SBT-CT ceramics exhibit the high recoverable energy storage density of 4.0 J·cm^(-3)under electric field of 480 kV·cm^(-1).Its recoverable energy storage density varies by less than 8%in the temperature range of 30-150℃,indicating good temperature stability of the energy storage *** this work,the energy storage performance of barium titanate-based ceramics was greatly improved by transforming ferroelectrics into relaxor ferroelectrics and VPP method,which can bring new inspiration for the research of energy storage ceramics.

关键词： Barium titanate Energy storage Viscous polymer processing(VPP)

Initial densification strain point's determination of honeycomb structure subjected to out-of-plane compression

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Journal of Central South University 2017年第7期24卷 1671-1675页

作者： WANG zhong-gang ZHOU Wei LIU Jie-fu School of Traffic&Transportation Engineering Key laboratory of Traffic Safety on Track of Ministry of EducationCentral South UniversityChangsha 410075China CRRC Qingdao Sifang Co.Ltd. Qingdao 266111China

Compression ratio is significant for cellular structures on energy absorption. In the present work, theoretical formulas to determine the initial densification strain of honeycomb structure were put forward by means of minimum energy principle. Detailed densification strain points were identified, with full fold model for kinds of specimens. To validate, corresponding numerical simulations were carried out with explicit finite element method. Excellent agreement in terms of initial densification stain point has been observed between the theoretical calculation and numerical simulation. The results show that: (1) a different honeycomb structure has different initial densification strain point, and its geometric configuration of cells plays an evident role on densification; (2) half-wave length of the wrinkle of honeycomb in folding process significantly influences on the densification strain point; (3) the initial densification point is an decreasing power function of the ratio of foil thickness to cell length, with the exponent 2/3. These achievements provide important references for design in cellular energy absorption devices.

关键词： honeycomb densification strain full fold element half-wave length

A facile electrochemical synthesis of caffeic acid derivatives in the presence of acetylacetone or methyl acetoacetate in aqueous medium

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Chinese Chemical Letters 2007年第2期18卷 130-132页

作者： Cheng Chu Zeng[a]&Email:zengcc@*** Li Ming Hu[a] Jia Zeng[a] Ru gang zhong[a] [a]College of Life Science & Bioengineering Beijing University of Technology Beijing 100022 China

The anodic oxidation of caffeic acid in the presence of acetylacetone or methyl acetoacetate in aqueous solution has been studied by cyclic voltammetry and controlled-potential electrolysis techniques. The result showed that caffeic acid was oxidized to the corresponding o-benzoquinone, which underwent further Michael-addition with acetylacetone or methyl acetoacetate to produce caffeic acid derivative 3,4-dihydroxy-6-(1-acetylacetone)-yl cinnamic acid 4a or 3,4-dihydroxy-6-(1-acetyl-methylacetate)-yl cinnamic acid 4b.

关键词： Caffeic acid Electrochemical synthesis Acetylacetone Methyl acetoacetate

A modified Johnson–Cook model for 7N01 aluminum alloy under dynamic condition

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Journal of Central South University 2017年第11期24卷 2550-2555页

作者： ZHANG Yi-ben YAO Song HONG Xiang WANG zhong-gang Key Laboratory of Traffic Safety on Track of Ministry of Education School of Traffic and Transportation EngineeringCentral South UniversityChangsha 410075China

Tensile tests at different strain rates(0.0002, 0.002, 0.02, 1000 and 3000 s^(-1)) were carried out for 7N01 aluminum alloy. Low strain rate experiments(0.0002, 0.002 and 0.02 s^(-1)) were conducted using an electronic mechanical universal testing machine, while high strain rate experiments(1000, 3000 s^(-1)) were carried out through a split Hopkinson tensile bar. The experimental results showed that 7N01 aluminum alloy is strain rate sensitive. By introducing a correction scheme of the strain rate hardening coefficient, a modified Johnson–Cook model was proposed to describe the flow behaviors of 7N01 aluminum alloy. The proposed model fitted the experimental data better than the original Johnson–Cook model in plastic flow under dynamic condition. Numerical simulations of the dynamic tensile tests were performed using ABAQUS with the modified Johnson–Cook model. Digital image correlation was used together with high-speed photography to study the mechanical characters of specimen at high strain rate. Good correlations between the experiments results, numerical predictions and DIC results are achieved. High accuracy of the modified Johnson-Cook model was validated.

关键词： aluminum alloy constitutive relation modified Johnson–Cook model high strain rate digital image correlation finite element analysis

STUDY ON SPATIAL AUTOCORRELATION OF URBAN LAND PRICE DISTRIBUTION IN CHANGZHOU CITY OF JIANGSU PROVINCE

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Chinese Geographical Science 2006年第2期16卷 160-164页

作者： LIU zhong-gang LI Man-chun SUN Yan MA Wen-bo Department of Urban and Resources Sciences Nanjing University Nanjing 210093 P. R. China National Research Center for Resettlement Hohai University Nanjing 210098 P. R. China College of Civil Engineering Nanjing Un＆ersity of Technology Nanjing 210009 P. R. China

This paper uses a spatial statistics method based on the calculation of spatial autocorrelation as a possible approach for modeling and quantifying the distribution of urban land price in Changzhou City, Jiangsu Province. GIS and spatial statistics provide a useful way for describing the distribution of urban land price both spatially and temporally, and have proved to be useful for understanding land price distribution pattern better. In this paper, we apply the statistical analysis method to 8379 urban land price samples collected from Changzhou Land Market, and it is turned out that the proposed approach can effectively identify the spatial clusters and local point patterns in dataset and forms a general method for conceptualizing the land price structure. The results show that land price structure in Changzhou City is very complex and that even where there is a high spatial autocorrelation, the land price is still relatively heterogeneous. Furthermore, lands for different uses have different degrees of spatial autocorrelation. Spatial autocorrelation of commercial lands is more intense than that of residential and industrial lands in regional central district. This means that treating land price as integration of homogeneous units can limit analysis of pattern, over-simplifying the structure of land price, but the methods, just as the autocorrelation approaches, are useful tools for quantifying the variables of land price.

关键词： spatial autocorrelation land price Moran's I GIS Changzhou