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Current status of radiology in China

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World journal of Gastroenterology 2000年第2期6卷 193-197页

作者： Zeng SM Zhou KR Zhang ZY Peng Wj Yang FH Lin j Yang j Han XY Shanghai Med Univ Zhongshan Hosp Dept Radiol Shanghai 200032 Peoples R China

INTRODUCTIONRadiology has been greatly advanced in China sinceits founding in 1949 and has been developed fasterand further more since China adopted the policy ofsocioeconomic reform in *** plays anincreasingly important role in the medical healthcare and treatment in the country and has reachedthe world’s advanced level in certain *** nowbriefly review the history of China’s radiology so asto give a clear picture of its development.

关键词： radiology/history radiology/leducation radiology/trends China

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DSS设计:对决策支持的一个系统化看法

计算机科学 1987年第4期 45-52页

作者： Gad Ariav michael j. Ginzberg 仲源

对DSS的系统化看法可以为有效设计DSS提供一具体框架结构,也为积累DSS研究成果奠定了基础。

关键词： DSS 决策过程决策支持

EFFECT OF BRAZING TIME ON TiC CERMET/IRON jOINT BRAZED WITH Ag-Cu-Zn FILLER METAL

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Acta Metallurgica Sinica(English Letters) 2004年第1期17卷 107-110页

作者： L.X.Zhang j.C.Feng Z.R.Li H.j.Liu National Key Laboratory of Advanced Welding Production Technology Harbin Institute of Technology Harbin 150001 ChinaNational Key Laboratory of Advanced Welding Production Technology Harbin Institute of Technology Harbin 150001 ChinaNational Key Laboratory of Advanced Welding Production Technology Harbin Institute of Technology Harbin 150001 ChinaNational Key Laboratory of Advanced Welding Production Technology Harbin Institute of Technology Harbin 150001 China

The brazing of TiC cermet to iron was carried out at 1223K for 5-20min using Ag-Cu-Zn filler metal. The formation phase and interface structure of the joints were investigated by electron probe microanalysis (EPMA), scanning electron microscopy (SEM) and X-ray diffraction (XRD), and the joint strength was tested by shearing method. The results showed: there occurred three new formation phases, Cu(s.s), FeNi and Ag(s.s) in TiC cermet/iron joint. The interface structure was expressed as TiC cermet/Cu(s.s)+FeNi/Ag(s.s)+a little Cu(s.s)+a little FeNi/Cu(s.s)+FeNi/iron, With brazing time increasing, there appeared highest shear strength of the joints, the value of which was up to 252.2MPa when brazing time was 10min.

关键词： brazing TiC cermet interface shear strength

Assessing dominant factors affecting soil erosion using a portable rainfall simulator

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International journal of Sediment Research 2008年第4期23卷 376-386页

作者： j.VAHABI D.NIKKAMI Soil Conservation and Watershed Management Research Institute

Investigating the causes of soil erosion is difficult in natural conditions owing to the presence of other factors. Without simplifying the experimental conditions, studying soil behavior with its numerous parameters while considering factors such as vegetation cover, topography, and rainfall is difficult and in most conditions impossible. The application of simulation approaches is therefore necessary to simplify the prototype. In this research, the effects of physical soil factors such as texture and antecedent soil moisture, along with land slope and vegetation cover were evaluated in the Taleghan watershed, Iran, using a rainfall simulator and soil erosion plots. For this purpose, a 89 × 120 cm rainfall simulator producing 24.5 and 32 mm/h rainfall intensities of 30 min duration, as a common condition of the study area, was used at 144 locations over soil erosion plots with dimensions of 95 × 125 cm. Plots had slope classes of 12–20 and 20–30 %, different soil textures, different antecedent soil moistures, and medium to poor vegetation cover conditions. It was found that for 24.5 and 32 mm/h rainfall intensities, the sediment yield had high correlations of –0.771 and –0.796 with vegetation cover and slight correlations of 0.045 and 0.029 with land slope respectively. Regression equations for predicting the sediment yield were also developed for different conditions.

关键词： Rainfall simulator Soil erosion Soil physical parameters Vegetation cover Taleghan watershed Iran

DAMPING BEHAVIOR OF ULTRAFINE-GRAINED PURE ALUMINUM L2 AND THE DAMPING MECHANISM

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Acta Metallurgica Sinica(English Letters) 2006年第3期19卷 223-227页

作者： Z.M. Zhang C.j. Xu j.C. Wang H.Z. Liu School of Materials Science ＆ Engineering Xi＇an University of Technology Xi＇an 710048 Ghina State Key Laboratory of Solidification Processing Northwestern Polytechnical University Xi＇an 710072 Ghina

Ultrafine-grained pure aluminum L2 with a mean grain size of 1.01μm was produced by equal channel angular pressing （ECAP） and annealing at 150℃ for 2h. Damping behavior of the alloy was measured using a dynamic mechanical thermal analyzer. The alloy had an excellent damping capacity Q^-1 with the ambient value being 9.8×10^-3 at 1.0Hz when the strain amplitude was 2.0×10^-5. The damping behavior of the alloy showed a non-linear damping variation tendency, that is, with an increase in temperature and a decrease of frequency, the damping capacity of the alloy increased. The damping capacity increased with the strain amplitude when the strain amplitude was less than 4.6×10^-5. When the strain amplitude was higher than 4.6×10^-5, the damping capacity became a constant and independent of strain amplitude. The high damping capacity was attributed to dislocation unpinning and a drag of dislocation on pinning points.

关键词： ECAP ultrafine grain damping capacity aluminum alloy

A Mathematical Analysis of Scale Similarity

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Communications in Computational Physics 2017年第1期21卷 149-161页

作者： Z.j.Wang Yanan Li Department of Aerospace Engineering University of Kansas2120 Learned HallLawrenceKS 66045USA

Scale similarity is found in many natural phenomena in the universe,from fluid dynamics to *** large eddy simulations of turbulent flows,some sub-grid scale(SGS)models are based on scale *** earliest scale similarity SGS model was developed by Bardina et al.,which produced SGS stresses with good correlation to the true *** the present study,we perform a mathematical analysis of scale *** analysis has revealed that the ratio of the resolved stress to the SGS stress is g2,where g is the ratio of the second filter width to the first filter width,under the assumption of small filter *** implications of this analysis are discussed in the context of large eddy simulation.

关键词： Scale similarity large eddy simulation sub-grid scale models

SUPERPLASTICITY OF A Ni-28.5Al-20.4Fe INTERMETALLIC ALLOY

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Acta Metallurgica Sinica(English Letters) 2000年第3期13卷 888-892页

作者： Zhou, W.L. Guo, j.T. Chen, R.S. Zhou, j.Y. Inst of Metal Research Chinese Acad of Sciences Shenyang China

Our previous investigation examined the superplastic behavior of an extruded Ni-28.5Al-20.4Fe alloy. Its tensile properties were determined at temperature from 1123 K to 1323 K and initial strain rates from 1.04×10-2s-1 to 1.04×10-4s-1. A maximum elongation of 233% was obtained at 1123 K and a strain rate of 5.2×10-4s-1. Furthermore, microstructural features, such as decrease in the average grain size after deformation at 850 °C and 980 °C, the presence of many dislocation-free grains adjacent to grains with a high dislocation density, indicate that dynamic recrystallization has occurred as an efficient accommodation mechanism. SEM examination of the fracture sample after superplastic deformation reveals many voids on the fracture surface. By correlating with the result of TEM observation, it is suggested that the superplastic deformation in this alloy should be controlled by a grain boundary sliding-based mechanism accommodated by the movement of dislocation and dynamic recrystallization.

关键词： Activation energy Aluminum alloys Intermetallics Iron alloys Microstructure Recrystallization (metallurgy) Superplasticity Tensile testing

Strategies to improve fiber utilization in swine

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journal of Animal Science and Biotechnology 2013年第2期4卷 112-123页

作者： Brian j Kerr Gerald C Shurson USDA-ARS-National Laboratory for Agriculture and the Environment University of Minnesota

Application of feed processing methods and use of exogenous feed additives in an effort to improve nutrient digestibility of plant-based feed ingredients for swine has been studied for decades. The following review will discuss several of these topics, including： fiber characterization, impact of dietary fiber on gastrointestinal physiology, energy, and nutrient digestibility, mechanical processing of feed on fiber and energy digestibility, and the use of exogenous enzymes in diets fed to growing pigs. Taken together, the diversity and concentration of chemical characteristics that exists among plant-based feed ingredients, as well as interactions among constituents within feed ingredients and diets, suggests that improvements in nutrient digestibility and pig performance from mechanical processing or adding exogenous enzymes to diets fed to swine depends on a better understanding of these characteristics, but also relating enzyme activity to targeted substrates. It may be that an enzyme must not only match a target substrate（s）, but there may also need to be a ＇cocktail＇ of enzymes to effectively breakdown the complex matrixes of fibrous carbohydrates, such that the negative impact of these compounds on nutrient digestibility or voluntary feed intake are alleviated. With the inverse relationship between fiber content and energy digestibility being well described for several feed ingredients, it is only logical that development of processing techniques or enzymes that degrade fiber, and thereby improve energy digestibility or voluntary feed intake, will be both metabolically and economically beneficial to pork production.

关键词： Energy Enzymes Fiber Growing-finishing pigs Nutrient digestibility Processing

Nonlinear robust H-infinity filtering for a class of uncertain systems via convex optimization

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控制理论与应用（英文版） 2012年第2期10卷 152-158页

作者： Masoud ABBASZADEH Horacio j. MARQUEZ United Technologies Research Center East HartfordCT 06108U.S.A. Department of Electrical and Computer Engineering University of AlbertaEdmontonAlbertaCanada T6G 2V4

A new approach for robust H-infinity filtering for a class of Lipschitz nonlinear systems with time-varying uncertainties both in the linear and nonlinear parts of the system is proposed in an LMI framework. The admissible Lipschitz constant of the system and the disturbance attenuation level are maximized simultaneously through convex multi-objective optimization. The resulting H-infinity filter guarantees asymptotic stability of the estimation error dynamics with exponential convergence and is robust against nonlinear additive uncertainty and time-varying parametric uncertainties. Explicit bounds on the nonlinear uncertainty are derived based on norm-wise and element-wise robustness analysis.

关键词： Nonlinear uncertain systems Robust observers Nonlinear H-infinity filtering Convex optimization