检索结果-南通市图书馆

Preparation and UV property of size-controlled monodisperse nickel nanoparticles (<10 nm) by reductive method

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

Rare Metals 2013年第2期32卷 179-185页

作者： Xiao guo Feng Zheng min guo Mei Zhang Kuo-Chih Chou State Key Laboratory of Advanced Metallurgy School of Metallurgical and Ecological EngineeringUniversity of Science and Technology Beijing

Nickel nanoparticles （〈10 nm） were success fully synthesized using a reductive method of nickel chloride with sodium borohydride in the ethanol/poly vinylpyrrolidone （PVP） system. The effects of three fac tors, such as the concentration of the nickel ions, the time of reaction, and the amount of PVP （surfactant）, were discussed. The possible growth process of the particles and optimum reactive conditions was also investigated. The result of transmission electron microscopy （TEM） reveals that these nickel nanoparticles are spherical. The average diameter could be controlled as 25 nm under selected conditions. Highresolution TEM and energydispersive spectroscopy results indicates that the nickel nanoparticles are pure. The UVvisible light absorption spectrum shows that the peaks of nickel nanoparticles moves toward the short wavelength along with the decrease of sizes.

关键词： Reductive method Nickel nanoparticles Size controllable UV-visible light absorption

Interior Regularity on the Abreu Equation

在线全文

学校读者我要写书评

暂无评论

Acta Mathematica Sinica,English Series 2013年第1期29卷 33-38页

作者： bo Hui CHEN An-min LI Li SHENG Yangtze Center of Mathematics Department of Mathematics Sichuan University Department of Mathematics Sichuan University

In this paper, we prove the interior regularity for the solution to the Abreu equation in any dimension assuming the existence of the C^0 estimate.

关键词： Toric geometry Abreu's equation interior estimates

An Effective Medium Approximation of Nonlinear Composites with Spherical Particle

在线全文

学校读者我要写书评

暂无评论

Chinese Physics Letters 2001年第7期18卷 960-962页

作者： WEI En-bo GU guo-Qing College of Power Engineering University of Shanghai for Science and TechnologyShanghai 200093

We have proposed a nonlinear effective medium approximation(EMA)method to estimate the bulk effective conductivities of weakly nonlinear composite media,which obey a current-field relation of the form J=σE+X|E|2 *** an example in three dimensions,we apply the EMA method to deal with a spherical inclusion in a host and derive the approximate analytic formulas of nonlinear effective response,which are suitable for the larger volume fraction of spherical *** our results,we can exactly obtain the generalized Landau formulas in the dilute limit.

关键词： nonlinear formulas spherical

Microstructure and texture evolution of Mg–3Zn–1Al magnesium alloy during large-strain electroplastic rolling

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

International Journal of minerals,Metallurgy and Materials 2015年第4期22卷 411-416页

作者： Yan-bin Jiang Lei Guan guo-yi Tang bo Cheng Da-bo Liu Key Laboratory for Advanced Materials Processing of the ministry of Education Institute of Advanced Materials and Technology University of Science and Technology Beijing Beijing Institute of Aeronautical Materials Aviation Industry Corporation of China Advanced Materials Institute Graduate School at Shenzhen Tsinghua University

Large-strain deformation by single electroplastic rolling （EPR） was imposed on AZ31 magnesium alloy strips. During EPR at low temperature （150-250℃）, numerous twins formed in the alloy. After EPR at a high temperature （350℃）, the number of twins reduced and some dynamic recrystallization （DRX） grains formed at grain boundaries and twinned regions. The synergic thermal and athermal effects generated by electropulsing, which promoted dislocation motion, induced a few small DRX grains, and ductile bandings were mainly re- sponsible for large-strain deformation during EPR. The inclination angle of the basal pole stemmed from the counterbalance of the inclina- tion direction of the basal pole between the DRX grains and deformed coarse grains.

关键词： magnesium alloys electroplastic rolling microstructure texture recrystallization

Interaction of humic substances and hematite:FTIR study

在线全文

学校读者我要写书评

暂无评论

Journal of Environmental Sciences 2005年第1期17卷 43-47页

作者： FUHong-bo QUANXie CHENShuo ZHAOHui-min ZHAOYa-zhi SchoolofEnvironmentalandBiologicalScienceandTechnology DalianUniversityofTechnologyDalian116023China

The present work extended the knowledge on the binding and complexation of humic substances(humic acid or fulvic acid) and hematite by Fourier transform infrared spectroscopy(FTIR). The FTIR data gained gave the consist evidences by two different sampling preparation methods that the interaction mechanism between humic substances and hematite was mainly conform to the ligand exchange involving carboxylic functional groups of humic substances and the surfaces sites of hematite. The present method, although associated with some uncertainties, provided an opportunity to increase the knowledge in this field.

关键词： humic substances fulvic acid humic acid hematite FTIR complex

Insight into element segregation mechanisms during creep in γ'-strengthened Co-based superalloy by elastoplastic phase-field simulation

在线全文

学校读者我要写书评

暂无评论

Progress in Natural Science:Materials International 2024年第5期34卷 873-879页

作者： Jia Chen min guo min Yang Tingting Cui borong Cui Jun Zhang State Key Laboratory of Solidification Processing Northwestern Polytechnical University

The element segregation accompanying the creep process has been shown to significantly affect the deformation resistance of the superalloys. However, the processing and mechanism of element segregation are still *** paper investigated the concentration evolution of a model Co–9Al–9W(at. %) alloy during 900°C/275 MPa using developed ternary elastoplastic phase-field model coupled with CALPHAD method and crystal plasticity model. The results of simulation show that co-depletion of Al and W element occurs in γ' precipitate and in γ side at γ/γ' interface, and this depletion is gradually increasing with the accumulation of plastic strain. From the perspective of changes of driving force of element diffusion, it is found that these segregation phenomena are attributed to the high elastic potential caused by the large local plastic strain. In addition, the effects of these segregations on creep property are also predicted. The current research provides a new method for exploring the mechanism of element diffusion.

关键词： Element segregation Creep Phase-field simulation Co-based superalloys

A Wavelet and Neural Networks Based on Fault Diagnosis for HAGC System of Strip Rolling Mill

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Journal of Iron and Steel Research International 2011年第1期18卷 31-35页

作者： LI guo you DONG min Key Laboratory of InduslriaI Computer Control Engineering of Hebei Province Yanshan University Qinhuangdao 066004 Hebei China College of Mechanical Engineering Yanshan University Qinhuangdao 066004 Hebei China

The fault diagnosis of HAGC （Hydraulic Gauge Control） system of strip rolling mill is researched. Taking the advantage of the accompanying characteristics of the closed loop control system, rolling force forecasting model is built based on neural networks. The comparison results of the prediction and the actual signal are taken as residual signals. Wavelet transform is used to obtain the components of high and low frequency of the residual signal. Wave let decomposition results make fault feature clear and time-domain positioning accurately. Fault numerical criterion is established through Lipschitz exponent. By analyzing the varied fault features which correspond to varied fault rea sons, the fault diagnosis of HAGC system is implemented successfully.

关键词： HAGC fault diagnosis neural network wavelet transform

Gas Holdups of Small and Large Bubbles in a Large-scale Bubble Column with Elevated Pressure

在线全文

学校读者我要写书评

暂无评论

Chemical Research in Chinese Universities 2004年第4期20卷 462-465页

作者： JINHai-bo YANGSuo-he ZHANGTong-wang TONGZe-min DepartmentofChemicalEngineering BeijingInstituteofPetrochemicalTechnologyBeijing102617P.R.China

Gas holdups of large bubbles and small bubbles were measured by means of dynamic gas disengagement approach in the pressured bubble column with a diameter of 0.3 m and a height of 6.6 m. The effects of superficial gas velocity, liquid surface tension, liquid viscosity and system pressure on gas holdups of small bubbles and large bubbles were investigated. The holdup of large bubbles increases and the holdup of small bubbles decreases with an increase of liquid viscosity. Meanwhile, the holdup of large bubbles decreases with increasing the system pressure. A correlation for the holdup of small bubbles was obtained from the experimental data.

关键词： Bubble column Elevated pressure Large bubble Small bubble Holdup

Compressive properties of homemade carbon fiber composite laminates with delamination defect

在线全文

学校读者我要写书评

暂无评论

航空动力学报 2013年第1期28卷 10-15页

作者： FU Hui-min YANG Yu-song ZHANG Yong-bo Research Center of Small Sample Technology Beijing University of Aeronautics and Astronautics

Large numbers of aircraft composite structures were researched,and the distribution of delamination sizes and though thickness positions in the composite laminates were *** experiment was conducted to probe into the effect of delamination sizes and through thickness positions on the compressive strengths of laminates with single embedded circular delamination with the most dangerous delamination sizes and positions defined from the distribution.A shell model was established for compressive strength prediction,and the virtual crack closure technique(VCCT) was employed for the strain energy release rate *** finite element(FE) prediction was in good agreement with the experimental measurements,for the predicted compressive strengths stood within 10%error of experimental *** was observed that the compressive strength was highly effected by the delamination size,while the though thickness position of delamination did not have significant effect on the compressive strength.

关键词： homemade carbon fiber composite compressive strength virtual crack closure technique element simulation