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Decomposition of C_(70) and C_(60) Under Laser Irradiation Monitored by Raman Spectroscopy

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Chinese Physics Letters 1992年第11期9卷 621-622页

作者： cheng guangxu ZANG Wencheng YANG Ping WANG Wennai gu gang DOU Youwei FENG Duan Center of Material Analysis Nanjing UniversityNanjing 210008 the National Laboratory of Solid State Microstructures Nanjing UniversityNanjing 210008

The degradation of C_(60) in organic solution by light has been reported by Taylor et al.[Nature,351(1991)277].The powders of the mixture of C_(60) and C_(70) prepared by arc heating ofgraphite electrodes in the environment of He gas was not to be stable with respect to intense irradiation of argon laser(488.0nm),as monitored by Raman spectrascopy,C_(70) is found to be first decomposed into fragmentary graphite,then C_(60) followed *** is interesting to note that besides graphite,some traces of diamond-like structure are shown confirming some speculations of Mackay[Nature,352(1991)762].

关键词： powders graphite fir

Effect of Carburization on the Mechanical Properties of Biomedical Grade Titanium Alloys

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Journal of Bionic Engineering 2011年第1期8卷 86-89页

作者： Yong Luo Haibo Jiang gang cheng Hongtao Liu Institute of Tribology and Reliability Engineering School of Material Science and Engineering China University of Mining and Technology Xuzhou 221116 P. R. China Mechanical and Electrical Engineering Institute Xuzhou Normal University Xuzhou 221116 P. R. China

Titanium cermets were successfully synthesized on the surface of biomedical grade titanium alloys by using sequential carburization method. The mechanical properties such as hardness, fracture toughness and plasticity were measured to estimate the potential application of titanium cermets. The results show that after carburization the surface hardness of titanium cermets was 778 HV, with a significant improvement of 128% compared with that of titanium alloys. In addition, the fracture toughness of titanium cermets was 21.5 × 10^6 Pa.m^1/2, much higher than that of other ceramics. Furthermore, the analysis of the loading-unloading curve in the nanoindentation test also indicates that the plasticity of titanium cermet reached 32.1%, a relatively high value which illustrates the combination of the metal and ceramics properties. The results suggest that sequential carburization should be an efficient way to produce titanium cermets with hard surface, high toughness and plasticity.

关键词： titanium alloys hardness surfaces ceramics sequential carburization

Experimental study of drag reduction characteristics related to the multifactor coupling of a bionic jet surface

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Journal of Hydrodynamics 2019年第1期31卷 186-194页

作者： Yun-qing gu Song-wei Yu Jie-gang Mou Tian-xing Fan Shui-hua Zheng gang Zhao College of Mechanical Engineering Zhejiang University of TechnologyHangzhou 310014China College of Mechanical and Electrical Engineering Harbin Engineering UniversityHarbin 150001China

To study the drag reduction of a jet surface,an experiment is conducted with a gyrorotor *** aim of this study is to analyze the influence of the jet aperture,the jet angle and the rotational velocity coupled with the jet velocity on the friction torque acting on a jet surface model by using a jet surface drag reduction testing experimental *** drag reduction characteristics of the jet surface are also *** results show that the maximum drag reduction rate is attained when the jet diameter is 5 mm and the jet velocity is 1.2 m/*** influence of the jet velocity on the drag reduction rate decreases as the diameter ***,the maximum drag reduction rate can be attained when the angle of the jet is 30° and the velocity of the jet is 1.0 m/*** the jet diameter is small,the influence of the jet velocity on the drag reduction rate is small,whereas the maximum drag reduction rate is attained when the jet angle is 30° and the jet velocity is 1.0 m/*** the jet angle is 15°,the drag reduction rate fluctuation is *** maximum drag reduction rate is attained when the rotational velocity is 2 100 r/min and the jet velocity is 1.0 m/*** results show that the best scheme is A2B2D3 A maximum drag reduction rate of 8.57% can be *** effective control of the jet effect on the separation of the boundary layer demonstrates the drag reduction principle of a bionic jet surface.

关键词： Drag reduction bionic jet surface friction torque coupling experiment

Anemone medicinal plants:ethnopharmacology,phytochemistry and biology

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Acta Pharmaceutica Sinica B 2017年第2期7卷 146-158页

作者： Da-cheng Hao Xiaojie gu Peigen Xiao Biotechnology Institute School of Environment and Chemical EngineeringDalian Jiaotong UniversityDalian 116028China Institute of Medicinal Plant Development Chinese Academy of Medical SciencesBeijing 100193China

The Ranunculaceae genus Anemone(order Ranunculales),comprising more than 150 species,mostly herbs,has long been used in folk medicine and worldwide *** medicinal compounds have been found in Anemone plants,especially triterpenoid saponins,some of which have shown anti-cancer *** Anemone compounds and extracts display immunomodulatory,antiinflammatory,antioxidant,and antimicrobial *** than 50 species have ethnopharmacological uses,which provide clues for modern drug *** compounds exert anticancer and other bioactivities via multiple ***,a comprehensive review of the Anemone medicinal resources is *** here summarize the ethnomedical knowledge and recent progress on the chemical and pharmacological diversity of Anemone medicinal plants,as well as the emerging molecular mechanisms and functions of these medicinal *** phylogenetic relationships of Anemone species were reconstructed based on nuclear ITS and chloroplast *** molecular phylogeny is largely congruent with the morphology-based *** used medicinal herbs are distributed in each subgenus and section,and chemical and biological studies of more unexplored taxa are *** expression profiling and relevant "omics" platforms could reveal differential effects of ***,transcriptomics,proteomics,and metabolomics should be highlighted in deciphering novel therapeutic mechanisms and utilities of Anemone phytometabolites.

关键词： Anemone Ethnomedicine Chemodiversity Bioactivity Molecular mechanism Pharmacophylogeny

Study on the passive film formed on 2205 stainless steel in acetic acid by AAS and XPS

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International Journal of Minerals,Metallurgy and Materials 2009年第2期16卷 170-176页

作者： Xue-qun cheng Xiao-gang Li Chao-fang Dong Corrosion and Protection Center University of Science and Technology Beijing Beijing 100083 China

The properties of the passive film formed on 2205 stainless steel in acetic acid at high temperature that contained chloride ions were studied by atomic absorption spectrometry （AAS）, X-ray photoelectron spectroscopy （XPS）, and electrochemical polarization measurements. AAS results show that molybdenum is enriched on the surface as the passive film is dissolved. This enrichment decreases the corrosion resistance because it hinders chloride adsorption and Fe ion dissolution, and acts as a local pH buffer because it consumes protons. The dissolution ratio of Fe/Cr is approximately 10 during the active dissolution of the passive film. XPS results indicate that when the potential is in the passivation region, Cr comprises about 50% of the metal cations in the near-surface region of the passive film and is the main metal constituent in this region. When the polarization potential is much greater than the transpassivation potential, the Mo content accounts for approximately 45% of the metal cations in the nearurface region; Fe and Ni have no obvious influence on the formation, dissolution, or puncture of the passive film.

关键词： acetic acid corrosion electrochemical behavior stainless steel passive film

T-Q diagram analyses and entransy optimization of the organic flash cycle(OFC)

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Science China(Technological Sciences) 2015年第4期58卷 630-637页

作者： WANG Wen Hua cheng Xue Tao LIANG Xin gang Key Laboratory for Thermal Science and Power Engineering of Ministry of Education School of AerospaceTsinghua University

The electrical power generation from low temperature heat source attracts more and more attentions but the temperature mismatching between the heat sources and working medium in the organic Rankine cycle(ORC)becomes an *** organic flash cycle(OFC)is an effective solution to this *** this paper,the OFC is analyzed by the concept of entransy loss and the T-Q(temperature-heat flow rate)diagram for the heat-work *** equations for cycles of the basic OFC and the OFC whose heat source is the exhaust gas of the turbine in a Brayton cycle(the combined cycle)are derived theoretically and the results indicate that larger entransy loss rate leads to larger output power with prescribed inlet parameters of the hot stream in the discussed cases,which is displayed by the T-Qdiagram *** numerical examples demonstrate that the optimal mass flow rate of the working medium for the maximum entransy loss rate is the same as that for the maximum output *** T-Qdiagram analyses is in accordance with the numerical *** concept of entransy loss can be used as the criteria for the OFC optimization.

关键词： OFC T. Q diagram entransy loss combined cycle optimization

Uniformity principle of temperature difference field in heat transfer optimization

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Chinese Physics B 2019年第6期28卷 245-253页

作者： Xue-Tao cheng Xin-gang Liang Department of Science and Technology of Anhui Province Hefei 230091China Key Laboratory for Thermal Science and Power Engineering of Ministry of Education Department of Engineering MechanicsTsinghua UniversityBeijing 100084China

The uniformity principle of temperature difference field is very useful in heat exchanger analyses and *** this paper, we analyze some other heat transfer optimization problems in the thermal management system of spacecrafts,including the cooling of thermal components, the one-stream series-wound heat exchanger network, the volume-to-point heat conduction problem, and the radiative heat transfer optimization problem, and have found that the uniformity principle of temperature difference field also holds. When the design objectives under the given constraints are achieved, the distributions of the temperature difference fields are uniform. The principle reflects the characteristic of the distribution of potential in the heat transfer optimization problems. It is also shown that the principle is consistent with the entransy theory. Therefore, although the principle is intuitive and phenomenological, the entransy theory can be the physical basis of the principle.

关键词： heat transfer optimization uniformity principle of temperature difference field equipartition of potential entransy theory

Structural bonding-breakage constitutive model for natural unsaturated clayey soils

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Acta Mechanica Sinica 2010年第6期26卷 931-939页

作者： guo-Qing Cai cheng-gang Zhao Xiao-Ming Qin Department of Geotechnique.School of Civil Engineering and Architecture Beijing Jiaotong University Beijing 100044China Hydro China Zhongnan Engineering Corporation Changsha 410014China

The natural clayey soils are usually structural and unsaturated,which makes their mechanical properties quite different from the remolded saturated soils.A structural constitutive model is proposed to simulate the bonding-breakage *** this model,the unsaturated soil element is divided into a cementation element and a friction element according to the binary medium theory,and the stress-strain coordination for these two elements is obtained. The cementation element is regarded as elastic,whereas the friction element is regarded as elastoplastic which can be described with the Gallipoli＇s *** theoretical formulation is verified with the comparative experiments of isotropic compressions on the saturated and unsaturated structural *** analyses of the effects of damage variables on the model predictions are further carried out,which show that breakage deformation of natural clayey soils increases with the rising amount of initial defects.

关键词： Unsaturated clayey soils Structure Micro-mechanism of bonding-breakage Constitutive model

A FEASIBLE DIRECTION ALGORITHM WITHOUT LINE SEARCH FOR SOLVING MAX-BISECTION PROBLEMS

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Journal of Computational Mathematics 2005年第6期23卷 619-634页

作者： Feng-min Xu cheng-xian Xu Hong-gang Xue Department of Mathematics of Faculty of Science Xi'an Jiaotong University Xi'an 710049 China

This paper concerns the solution of the NP-hard max-bisection problems. NCP functions are employed to convert max-bisection problems into continuous nonlinear programming problems. Solving the resulting continuous nonlinear programming problem generates a solution that gives an upper bound on the optimal value of the max-bisection problem. From the solution, the greedy strategy is used to generate a satisfactory approximate solution of the max-bisection problem. A feasible direction method without line searches is proposed to solve the resulting continuous nonlinear programming, and the convergence of the algorithm to KKT point of the resulting problem is proved. Numerical experiments and comparisons on well-known test problems, and on randomly generated test problems show that the proposed method is robust, and very efficient.

关键词： Max-Bisection problem Feasible direction algorithm NCP function Convergence