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Chinese Physics Letters 2011年第12期28卷 312-312页

作者： liu Tao huang Zheng National Key Laboratory for Electronic Measurement Technology and Key Laboratory of Instrumentation Science and Dynamic Measurement North University of ChinaTaiyuan 030051 Xi'an Institute of Electromechanical Information Technology Xi'an 710065

The authors withdraw the research paper“High-Efficiency Graphene Photo Sensor Using a Transparent Electrode”,which was published in Chinese Physics Letters 28(10),107301(2011),due to the major mistakes in management and experiment,which led to the authors adopting inappropriate data published without sufficient examination and permission processes.

关键词： Efficiency Photo mistake

Effect of trace tungsten on the microstructure of TiAl alloys containing Nb and B

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Rare Metals 2007年第4期26卷 323-329页

作者： liu Bin liu Yong huang Lan huang Jinsong ZHANG Yonghong huang Boyun State Key Laboratory of Powder Metallurgy Central South University Changsha 410083 China

New TiAl alloys, containing 45 at.% A1, 7 at.% Nb, x at.% W, and 0.15 at.% B （x = 0, 0.2, 0.4, and 0.7） were prepared by arc melting and drop casting consequently. Using optical microscopy, scanning electron microscopy （SEM）, and electron superprobe technologies, the effects of tungsten on the microstructural evolution of the TiA1 alloys, including the colony size and lamellar spacing, were analyzed. It was found that cellular structures and dendrites were formed in the as-cast TiA1 alloys, and heavy metals, such as niobium and tungsten, tend to segregate strongly at the interface of the cellular structures and dendrites. Trace tungsten can effectively impede the grain growth and narrow the interlamellar spacing. 0.4 at.% tungsten is more effective in refuting the microstructure of the TiAI alloys.

关键词： TiAl alloys tungsten grain size β(B2)phase microstructure

Research on ambiguity resolution aided with triple difference

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Journal of Systems Engineering and Electronics 2008年第6期19卷 1090-1096页

作者： liu Zhenkun huang Shunji Dept. of Electronic Engieering Univ. of Electronic Science and Technology of China Chengdu 610054 P. R. China

The ambiguity resolution in the field of GPS is investigated in detail. A new algorithm to resolve the ambiguity is proposed. The algorithm first obtains the floating resolution of the ambiguity aided with triple difference measurement. Decorrelation of searching space is done by reducing the ambiguity covariance matrix＇s dimension to overcome the possible sick factorization of the matrix brought by Z-transformation. In simulation, the proposed algorithm is compared with least-squares ambiguity decorrelation adjustment （LAMBDA）. The result shows that the proposed algorithm is better than LAMBDA because of lesser resolving time, which approximately reduces 20% resolving time. Thus, the proposed algorithm adapts to the high dynamic real-time applications.

关键词： carrier phase measurement integer ambiguity triple-difference measurement decorrelation.

GPS dynamic cycle slip detection and correction with baseline constraint

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Journal of Systems Engineering and Electronics 2009年第1期20卷 60-64页

作者： liu Zhenkun huang Shunji Dept. of Electronic Engieering Univ. of Electronic Science and Technology of China Chengdu 610054 P. R. China

When the cycle slips take place in the attitude determination of a moving platform, the precision of the attitude will be impaired badly. A method of cycle slip detection and correction is proposed, which is suitable to the dynamic measurement using GPS carrier phase： the cycle slips detection is first achieved by triple difference observables, then the cycle slips correction is performed with baseline length constraint. The simulation results show that the proposed method is effective to the dynamic cycle slips problem.

关键词： dynamic cycle slip dectection triple difference observable baseline constraint attitude determination.

Monitoring desertification processes in Mongolian Plateau using MODIS tasseled cap transformation and TGSI time series

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Journal of Arid Land 2018年第1期10卷 12-26页

作者： liu Qingsheng liu Gaohuan huang Chong State Key Laboratory of Resources and Environmental Information System Institute of Geographic Sciences and Natural Resources ResearchChinese Academy of SciencesBeijing 100111China Jiangsu Center for Collaborative Innovation in Geographical Information Resource Development and Application Nanjing 210023China

Most remote sensing studies assess the desertification using vegetation monitoring method. But it has the insufficient precision of vegetation monitoring for the limited vegetation cover of the desertification region. Therefore, it offers an alternative approach for the desertificafon research to assess sand dune and sandy land change using remote sensing in the desertification region. In this study, the indices derived from the well-known tasseled cap transformation （TCT）, tasseled cap angle （TCA）, disturbance index （DI）, process indicator （PI）, and topsoil grain size index （TGSI） were integrated to monitor and assess the desertification at the thirteen study sites including sand dunes and sandy lands distributed in the Mongolian Plateau （MP） from 2000 to 2015. A decision tree was used to classify the desertification on a regional scale. The average overall accuracy of 2000, 2005, 2010 and 2015 desertification classification was higher than 90%. Results from this study indicated that integration of the advantages of TCA, DI and TGSI could better assess the desertification. During the last 16 years, Badain Jaran Desert, Tengger Desert, and Ulan Buh Desert showed a relative stabilization. Otindag Sandy Land and the deserts of Khar Nuur, Ereen Nuur, Tsagan Nuur, Khongoryn Els, Hobq, and Mu Us showed a slow increasing of desertification, whereas Bayan Gobi, Horqin and Hulun Buir sandy lands showed a slow decreasing of desertification. Compared with the other 11 sites, the fine sand dunes occupied the majority of the Tengger Desert, and the coarse sandy land occupied the majority of the Horqin Sandy Land. Our findings on a three or four years＇ periodical fluctuated changes in the desertification may possibly reflect changing precipitation and soil moisture in the MR Further work to link the TCA, DI, TGSI, and PI values with the desertification characteristics is recommended to set the thresholds and improve the assessment accuracy with field investigation.

关键词： desertification MODIS desert sand dune sandy land Mongolian Plateau

Mobility of the Myard 5R Linkage Involved in “Gogu Problem”

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Chinese Journal of Mechanical Engineering 2009年第3期22卷 325-330页

作者： liu Jingfang huang Zhen LI Yanwen Robotics Research Center Yanshan Univers#y Qinhuangdao 066004 China

Since the traditional Griibler-Kutzbach criterion fails in many overconstrained mechanisms, developing a general mobility formula is a hot topic lasting for more than 150 years in mechanisms. GOGU systematically investigated various mobility methods, and pointed that the methods were not fit for two kinds of paradoxical overconstrained mechanisms. The mobility on the two kinds of mechanisms is regarded as ＂Gogu problem＂. The Modified Griibler-Kutzbach criterion has solved the mobility of the second kind of mechanisms in ＂Gogu problem＂, and has developed into a systematic mobility methodology. Myard 5R linkage is one of the single-loop mechanisms involved in ＂Gogu problem＂, its joint axes are distributed in space with special geometric conditions, which increases the difficulty of mobility analysis. The study is to calculate the global mobility of the Myard 5R linkage using the mobility methodology. Firstly, the mobility methodology based on screw theory is briefly introduced. Secondly, some homogeneous transforms are performed according to the D-H parameters and the invariance of the linkage plane symmetry is revealed, which provides an idea to judge a plane-symmetric loop. The special geometric features of the axes distribution are discussed as well. Finally, the global mobility of the Myard 5R linkage is determined by the Modified Grubler-Kutzbach criterion. The results show that the methodology can be applied to more paradoxical mechanisms.

关键词： overconstrained linkage screw theory mobility

Physical quantity synergy in the field of turbulent heat transfer and its analysis for heat transfer enhancement

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Chinese Science Bulletin 2010年第23期55卷 2589-2597页

作者： liu Wei liu ZhiChun huang SuYi School of Energy and Power Engineering Huazhong University of Science and Technology Wuhan 430074 China

Based on the principle of physical quantity synergy in the field of laminar heat transfer,and according to the models of zero equation and k-ε two equations for the turbulent flow,the synergy equations for both energy and momentum conservation in the turbulent heat transfer are *** synergy regulation among heat flux,mass flow and fluid driving force,and the mechanism of heat transfer enhancement it reflects are *** synergy principle of physical quantity in the thermal flow field is extended from laminar flow to turbulent *** principle is verified to be universal by the calculation of heat transfer enhancement in a tube with an insert of helical twisted ***,corresponding to the synergy relation among physical quantities in the turbulent flow field,the performance of convective heat transfer and flow resistance for the tubes with different heat transfer components and surface can be compared through theoretical and computational analysis,which thereby provides a guidance for designing heat transfer units and heat exchangers.

关键词：场协同原理传热强化湍流换热物理量动量守恒方程强化传热机理方程模型协同作用

Towards Stereochemical Control＂ Two Approaches for the Highly *** Construction of the Spirolactone Moieties of Some Stemona Alkaloids

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Chinese Journal of Chemistry 2013年第1期31卷 55-62页

作者： Shichuan Tuo Xuekui liu Peiqiang huang Department of Chemistry and Fujian Provincial Key Laboratory for Chemical Biology College of Chemistry and Chemical Engineering Xiamen University Xiamen Fujian 361005 China

Some Stemona alkaloids belonging to the tuberostemospironine group possess a spirolactone moiety with anti-configuration （C-9/C-9a）. In this paper, we describe two approaches to this structural unity. By using bromine atom as a traceless directing group, the SmI2-mediated reductive coupling of ketone 6 and fl-bromomethacrylate proceeded with complete anti-diastereoselectivity. In the absence of an a-directing （chelation） group, the one-pot reaction of the ketone derived from alcohol 15 with the organozinc reagent generated from bromomethacrylate af- forded spiro-a-methylene-y-lactone derivative 16 as a single diastereomer. These two highly diastereoselective methods would find application in the synthesis of stemona alkaloids containing anti-configured spiro-lactone/pyr- rolidine moieties. In addition, on the basis of our previous work, the total synthesis of （-）-9-epi-11-demethyl- sessilifoliamide J （11）, and an improved synthesis of （-）-9,11-di-epi-sessilifoliamide J （9） were accomplished.

关键词： Stemona alkaloids spirolactone SmI2 organozinc reagent sessilifoliamide J

From Simple to Smart:The Development of Sensor Network

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稀有金属材料与工程 2006年第A3期35卷 617-620页

作者： Ping liu Xunxiang huang Feng liu Lianghua Zhang Institute of Chemical Defense Beijing 102205 China

Sensor networks have come a long way since the first point-to-point analog *** development of industrial applications imposes more challenges on traditional sensors and sensor *** World Wide Web browsers and object-oriented programming techniques are also helping shaping the next generation of sensor *** a trend,smart sensor networks are getting more attention in industrial areas for the values they can bring into *** IEEE 1451 family of smart sensor interface standards tends to resolve the issues and problems associated with the proliferation and the heterogeneity of sensor *** evolution and current state of the art of sensor networks is captured in this article,where the characteristics of their generations are discussed under the networking *** is also pointed out that the challenges sensor networks will face and intends of this field.

关键词： development sensor network

Reliability Simulation and Design Optimization for Mechanical Maintenance

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Chinese Journal of Mechanical Engineering 2009年第4期22卷 594-601页

作者： liu Deshun huang Liangpei YUE Wenhui XU Xiaoyan Hunan Provincial Key Laboratory of Health Maintenance for Mechanical Equipment Hunan University of Science and Technology Xiangtan 411201 China

Reliability model of a mechanical product system will be newly reconstructed and maintenance cost will increase because failed parts can be replaced with new components during service, which should be accounted for in system design. In this paper, a reliability model and reliability-based design optimization methodology for maintenance are presented. First, based on the time-to-failure density function of the part of the system, the age distributions of all parts of the system during service are investigated, a reliability model of the mechanical system for maintenance is developed. Then, reliability simulations of the systems with WeibuU probability density functions are performed, the system minimum reliability and steady reliability for maintenance are defined based on reliability simulation during the life cycle of the system. Thirdly, a maintenance cost model is developed based on replacement rates of the parts, a reliability-based design optimization model for maintenance is presented, in which total life cycle cost is considered as design objective and system reliability as design constrain. Finally, the reliability-based design optimization methodology for maintenance is used to design of a link ring for the chain conveyor, which shows that optimal design with the lowest maintenance cost can be obtained, and minimum reliability and steady reliability of the system can satisfy requirement of system reliability during service of the chain conveyor.

关键词： maintenance reliability simulation design optimization