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2002年

作者： L.E. Smart j.m.f. gagan

来源：畅想之星图书光盘版（南... 评论

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规则结晶形态氮化铝颗粒的自蔓延高温合成

无机材料学报 2004年第6期19卷 1402-1406页

作者：傅仁利陈克新周和平费雷拉j.m.f. 南京航空航天大学材料科学与技术学院南京210016 清华大学新型陶瓷与精细工艺国家重点实验室北京100084 葡萄牙阿威罗大学玻璃与陶瓷工程系

以铝粉和AlN粉末为原料,按重量比60/40的比例进行混合,加入3wt％NH4f和3wt％碳黑,在8mPa的氮气气氛条件下进行高温自蔓延合成,合成产物为具有良好结晶形态的规则AlN颗粒.采用扫描电子显微镜(SEm)和X射线衍射仪(XRD)研究了加入NH4f和碳... 详细信息

以铝粉和AlN粉末为原料,按重量比60/40的比例进行混合,加入3wt％NH4f和3wt％碳黑,在8mPa的氮气气氛条件下进行高温自蔓延合成,合成产物为具有良好结晶形态的规则AlN颗粒.采用扫描电子显微镜(SEm)和X射线衍射仪(XRD)研究了加入NH4f和碳黑后合成产物形态和物相的变化情况.研究结果表明同时加入NH4f和碳黑使得燃烧过程出现了后烧现象,即样品可以维持在高温阶段较长的时间,促进了AlN气相的传输,最终使得AlN颗粒以较为规则的外形生长.

关键词：氮化铝自蔓延高温合成规则结晶颗粒

Surface morphology and impurity distribution of electron beam recrystallized silicon films on low cost substrates for solar cell absorber

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Rare metals 2006年第Z1期25卷 195-200页

作者： GROmBALL f müLLER j Department of mikrosystemtechnik Technische Universitt Hamburg-Harburg Hamburg 21073 Germany

A line shaped electron beam recrystallised polycrystalline silicon film on the low cost substrate was investigated for the use of the solar cell absorber. The applied EB energy density strongly influences the surface morphology of the film system. Lower EB energy density results in droplet morphology and the rougher SiO2 capping layer due to the low fluidity. With the energy increasing, the capping layer becomes smooth and continuous and less and small pinholes form in the silicon film. Tungstendisilicide (WSi2) is formed at the interface tungsten/silicon but also at the grain boundaries of the silicon. Because of the fast melting and cooling of the silicon film, the eutectic of silicon and tungstendisilicide mainly forms at the grain boundary of the primary silicon dendrites. The SEm-EDX analysis shows that there are no chlorine and hydrogen in the area surrounding a pinhole after recrystallization because of outgassing during the solidification.

关键词： polycrystalline silicon film solar cell recrystallization energy surface morphology outgassing

Interactive data styling and multifocal visualization for a multigrid web-based Digital Earth

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International journal of Digital Earth 2021年第3期14卷 288-310页

作者： m.j.Sherlock m.Hasan f.f.Samavati Department of Computer Science University of CalgaryCalgaryCanada

Globe-based Digital Earth(DE)is a promising system that uses 3D models of the Earth for integration,organization,processing,and visualization of vast multiscale geospatial *** growing size and scale of geospatial datasets present significant obstacles to interactive viewing and meaningful visualizations of these DE *** address these challenges,we present a novel web-based multiresolution DE system using a hierarchical discretization of the globe on both server and client *** presented web-based system makes use of a novel data encoding technique for rendering large multiscale geospatial datasets,with the additional capability of displaying multiple simultaneous *** the data needed for the current views and scales are encoded and *** leverage the power of GPU acceleration on the client-side to perform real-time data rendering and dynamic *** rendering of multiple views allows us to support multilevel focus+context visualization,an effective approach to navigate through large multiscale global *** client–server interaction as well as the data encoding,rendering,styling,and visualization techniques utilized by our presented system contribute toward making DE more accessible and informative.

关键词： Digital Earth Discrete Global Grid System data integration data fusion multilevel focus+context visualization spatial resolution context awareness

Variational Calculus With Conformable fractional Derivatives

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IEEE/CAA journal of Automatica Sinica 2017年第2期4卷 340-352页

作者： matheus j.Lazo Delfim f.m.Torres Instituto de matemática Estatística e Física-FURG Center for Research and Development in mathematics and Applications (CIDmA) Department of MathematicsUniversity of Aveiro

Invariant conditions for conformable fractional problems of the calculus of variations under the presence of external forces in the dynamics are studied. Depending on the type of transformations considered, different necessary conditions of invariance are obtained. As particular cases, we prove fractional versions of Noether's symmetry theorem. Invariant conditions for fractional optimal control problems, using the Hamiltonian formalism, are also investigated. As an example of potential application in Physics, we show that with conformable derivatives it is possible to formulate an Action Principle for particles under frictional forces that is far simpler than the one obtained with classical fractional derivatives.

关键词： Conformable fractional derivative fractional calculus of variations fractional optimal control invariant variational conditions Noether’s theorem

3D flow Past Transonic Turbine Cascade SE 1050-Experiment and Numerical Simulations

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journal of Thermal Science 2013年第4期22卷 311-319页

作者： D.imurda j.fürst m.Luxa Institute of Thermomechanics AS CR v.v.i.Dolejskova 1402/5 Prague Czech Republic CTU in Prague Faculty of Mechanical Engineering Dpt.of Technical MathematicsKarlovo Náměstí 13 Prague Czech Republic

This paper is concerned with experimental and numerical research on 3D flow past prismatic turbine cascade SE1050 （known in QNET network as open test case SE1050）. The primary goal was to assess the influence of the inlet velocity profile on the flow structures in the interblade channel and on the flow field parameters at the cascade exit and to compare these findings to results of numerical simulations. Investigations of 3D flow past the cascade with non-uniform inlet velocity profile were carried out both experimentally and numerically at subsonic （m2 = 0.8） and at transonic （m2 = 1.2） regime at design angle of incidence. Experimental data was obtained using a traversing device with a five-hole conical probe. Numerically, the 3D flow was simulated by open source code OpenfOAm and in-house code. Analyses of experimental data and CfD simulations have revealed the development of distinctive vortex structures resulting from non-uniform inlet velocity profile. Origin of these structures results in increased loss of kinetic energy and spanwise shift of kinetic energy loss coefficient distribution. Differences found between the subsonic and the transonic case confirm earlier findings available in the literature. Results of CfD and experiments agree reasonably well.

关键词： blade cascade vortex structures transonic flow CfD

Zebrafish as a possible bioindicator of organic pollutants with effects on reproduction in drinking waters

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journal of Environmental Sciences 2015年第7期27卷 254-260页

作者： m.martínez-Sales f.García-Ximénez f.j.Espinós Aquaculture and Environmental Research Group (ACUmA) Polytechnic University of Valencia

Organic contaminants can be detected at low concentrations in drinking water, raising concerns for human health, particularly in reproduction. In this respect, we attempted to use the zebrafish as a bioindicator to detect the possible presence of these substances in drinking water, aiming to define the most relevant parameters to detect these substances, which particularly affect the development and reproduction of zebrafish. To this end, batches of30 embryos with the chorion intact were cultured in drinking waters from different sources,throughout their full life-cycle up to 5 months, in 20 L tanks. Six replicates were performed in all water groups, with a total of 24 aquariums. Two generations（f0 and f1） were studied and the following parameters were tested： in the f0 generation, survival and abnormality rates evaluated at 5 dpf（days post-fertilization） and at 5 mpf（months post-fertilization）,the onset of spawning and the fertility rate from 3 mpf to 5 mpf, and the sex ratio and underdeveloped specimens at 5 mpf. furthermore, in the f0 offspring（f1）, survival and abnormality rates were evaluated at 5 dpf and the hatching rate at 72 hpf. These results revealed that the hatching rate is the most sensitive parameter to distinguish different levels of effects between waters during the early life stages, whereas the rate of underdeveloped specimens is more suitable at later life stages. Regarding adult reproduction, fertility rate was the most sensitive parameter. The possible reversibility or accumulative nature of such effects will be studied in future work.

关键词： Organic pollutants Bioindicator Development and reproduction parameters Drinking water Zebrafish

Comparison of artificial neural networks with empirical correlations for estimating the average cycle time in conical spouted beds

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Particuology 2019年第1期17卷 48-57页

作者： I. Estiatia m. Tellabidea j.f. Saldarriaga H. Altzibara f.B. freirec j.T. freirec m. Olazara Department of Chemical Engineering University of the Basque CountryP.O. box 644E48080 BilbaoSpain Department of Civil and Environmental Engineering Universidad de los AndesCr.1 Este 19A-40BogotaColombia Department of Chemical Engineering Federal University of Sao CarlosRod. Washington Luis-km 235P.O. box 67613565-905Sao CarlosSPBrazil

Conventional spouted beds have been extensively used in many real-life applications but are not suited for all types of materials, especially fine particles, which require internal devices to improve their motion in the spouted bed. However, unlike conventional spouted beds, there are almost no mechanistic or empirical models available for the design of spouted beds with internals. Given the availability of an extensive but not experimentally designed database, the main purpose of this study is to present an analysis of neural networks and empirical models in terms of their suitability to fit and predict average cycle times in conical spouted beds with and without draft tubes. The parameters investigated are particle size, density, contactor angle, gas inlet diameter, static bed height, and draft tube features. Although the amount of information is always a key factor when fitting models, the size of the database used in this study strongly affects the fitting performance of empirical models, whereas artificial neural networks are more influenced by how the data are scaled. Results of model verification show that both techniques are suitable for predicting average cycle times for data outside the range covered by the database.

关键词： Empirical correlation Artificial neural network Average cycle time Conical spouted bed Draft tubes modeling

Quantified evaluation of particle shape effects from micro-to-macro scales for non-convex grains

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Particuology 2016年第2期14卷 23-35页

作者： Y. Yang j.f. Wang Y.m. Cheng Department of Civil and Environmental Engineering The Hong Kong Polytechnic University Hong Kong China Department of Civil and Architectural Engineering City University of Hong Kong Hong Kong China

Particle shape plays an important role in both the micro and macro scales responses of a granular assem- bly. This paper presents a systematic way to interpret the shape effects of granular material during quasi-static shearing. A more suitable shape descriptor is suggested for the quantitative analysis of the macroscale strength indexes and contact parameters for non-convex grains, with special consid- eration given to the peak state and critical state. Through a series of numerical simulations and related post-processing analysis, particle shape is found to directly influence the strain localisation patterns, microscale fabric distributions, microscale mobilisation indexes, and probability distribution of the nor- malised contact normal force. Additionally, the accuracy of the stress-force-fabric relationship can be influenced by the average normal force and the distribution of contact vectors. moreover, particle shape plays a more important role than do the confining pressures in determining the friction angle. Strong force chains and the dilation effect are also found to be strongly influenced by the high confinin~ oressure.

关键词： Quantitative analysis Shape factor Statistical analysis micro-macro indexes

EBSD Characterization of microstructure and micro-texture in a friction Stir-Welded DP600 Steel

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Acta metallurgica Sinica(English Letters) 2023年第5期36卷 789-802页

作者： H.Ashrafi m.Shamanian m.Sanayei f.farhadi j.A.Szpunar faculty of Chemical and materials Engineering Shahrood University of TechnologyShahrood***Iran Department of materials Engineering Isfahan University of TechnologyIsfahan***Iran Department of mechanical Engineering University of SaskatchewanSaskatoonSKS7N 5A9Canada Department of materials Science and Engineering Worcester Polytechnic InstituteWorcesterMA01609USA

The microstructure and micro-texture in different areas of a friction stir(fS)-welded DP600 steel were investigated by means of electron backscatter *** volume fraction of martensite and non-polygonal ferrite was evaluated based on the image quality(IQ)*** of grain boundaries revealed that the fraction of sub-grain boundaries as well as that of low-angle grain boundaries in the heat-affected zone(HAZ)and stir zone(SZ)was more than doubled compared to those in the DP600 steel base metal(Bm).The micro-texture examination of the Bm showed strong{112}and{111}components with an intensity 4.6 times of that random *** texture showed a memory effect in the HAZ,with a reduced overall *** the SZ,D_(1),D_(2) and E shear texture components together with a cube component were *** of these texture components of ferrite were attributed to the transformation of B and R texture components of prior austenite,which are evidences of continuous dynamic recrystallization mechanism in the SZ of the friction stir-welded DP600 steel.

关键词： Dual phase steel friction stir welding micro-texture Image quality