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Microstructure and creep properties of Ni-based single-crystal superalloys with Mo/Al addition at 760℃/850 MPa

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Rare Metals 2023年第11期42卷 3806-3813页

作者： Pei-Shan Cao Hui Wang Yi Ru Yun-Fei Liang Sheng-Kai gong Key Laboratory of Aerospace Materials and Performance(Ministry of Education) School of Materials Science and EngineeringBeihang UniversityBeijing100191China

The effect of Mo and Al addition on the microstructure as well as creep rupture properties at760.C/850 MPa was investigated by transmission electron microscopy(TEM)in a Ni-based single-crystal(SC)alloy with the composition of Ni-6.5Al-8.0Mo-2.4Cr-6.2Ta-4.9Co-1.5Re-(0.01-0.05)Y(wt%).The microstructure analysis shows that 0.5 wt%Al addition induces rapid decrease in creep rupture life,and this can be attributed to the formation of dense stacking faults cutting intoγ'precipitates,which can be explained by the increase in Orowan stress caused by the narrowerγchannel width and the decrease in stacking faults ***,1.5 wt%Mo addition increases the anti-phase boundary energy and decreases the stacking faults energy,resulting in fewer stacking faults and thus a slight decrease in the creep rupture life.

关键词： Ni-based single-crystal superalloy Transmission electron microscopy Stacking faults Mo and Al addition Creep rupture properties

Zonal disintegration phenomenon in enclosing rock mass surrounding deep tunnels——Elasto-plastic analysis of stress field of enclosing rock mass

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Mining Science and Technology 2009年第3期19卷 84-90页

作者： WU Hao FANG Qin ZHANG Ya-dong gong Zi-ming Engineering Institute of Engineering Corps PLA University of Science and Technology Nanjing Jiangsu 210007 China

The zonal disintegration phenomenon （ZDP） is a typical phenomenon in deep block rock masses. In order to investigate the mechanism of ZDP, an improved non-linear Hock-Brown strength criterion and a bi-linear constitutive model of rock mass were used to analyze the elasto-plastic stress field of the enclosing rock mass around a deep round tunnel. The radius of the plastic region and stress of the enclosing rock mass were obtained by introducing dimensionless parameters of radial distance. The results show that tunneling in deep rock mass causes a maximum stress zone to appear in the vicinity of the boundary of the elastic and the plastic zone in the surrounding rock mass. Under the compression of a large tangential force and a small radial force, the rock mass in the maximum stress zone was in an approximate uniaxial loading state, which could lead to a split failure in the rock mass.

关键词： enclosing rock mass around deep tunnels zonal disintegration equivalent material Hoek-Brown strength criterion

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A TLP approach for BGP based on local speculation

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Science in China(Series F) 2008年第11期51卷 1772-1784页

作者： GAO Lei gong ZhengHu LIU YaPing LAI MingChe PENG Wei Department of Computer National University of Defense Technology Changsha 410073 China

With the explosive growth of Internet, the low efficiency of BGP has seriously influenced its usability. In this work, a TLP （thread level parallelism） approach with local speculation is proposed to improve the BGP performance. The thread partition is locally performed on each separated sub-module at route processing, and the speculation strategy is implemented to guarantee the memory consistency and sequential commit. Experiments on Intel Quad-core server show that this approach reaches an average speedup of 1.46 under single peer, multi-peers and route flapping. It is also shown that the packet throughput can be improved greatly under multiple sessions by taking advantage of TLP.

关键词： BGP multi-core local speculation parallelism

Automated String Constraints Solving for Programs Containing String Manipulation Functions

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Journal of Computer Science & Technology 2017年第6期32卷 1125-1135页

作者： Xu-Zhou Zhang Yun-Zhan gong Ya-Wen Wang Ying Xing Ming-Zhe Zhang State Key Laboratory of Networking and Switching Technology Beijing University of Posts and Telecommunications Beijing 100876 China Automation School Beijing University of Posts and Telecommunications Beijing 100876 China

The ability to solve various constraints is a principal factor of automatic constraint solvers. Most object-oriented languages treat a character string as a primitive data type which is manipulated by string library functions. Most constraint solvers have limitations on their input constraints, such as strong restrictions on the expressiveness of constraints or lack of the ability to solve hybrid constraints. These limitations hinder applying automated constraint solvers on program analysis techniques for programs containing strings and string manipulation functions. We propose an approach to automatically solve program constraints involving strings and string manipulation functions. Based on the character array model, we design a constraint language which contains primitive operations to precisely describe the constraints of commonly used string manipulation functions. The translated string constraints together with numeric constraints are then solved by a two- phase test generation procedure： firstly, a partial solution is obtained to satisfy the arithmetic constraints of the position variables, and the solution is utilized to simplify the string constraints into pure character array constraints; secondly, the pure array constraints are solved by an off-the-shelf array-specific theory based constraint solver. We integrate the approach into an automated testing tool to support the generation of string test cases, and then perform experiments. The results of the experiments prove that the integration of the proposed approach promotes the testing coverage of the existing testing tool, and the integrated tool has an advantage of handling specific string manipulation functions compared with an existing string solver.

关键词： string constraints solving satisfaction module theory program analysis software testing automated testinput generation

An Improved Semi-Orthogonal User Selection Algorithm Based on Condition Number for Multiuser MIMO Systems

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China Communications 2014年第A01期11卷 23-30页

作者： LU Xinlu WU Jun HUANG Xinlin LI Wenfeng LU Jianmin gong Zhengwei ComputerScienceandTechnologyDepartment TongjiUniversityShanghai201804China HuaweiTechnologiesCo. LtdShanghai201206China

In Multiple-Input Multiple-Out （MIMO） systems, the user selection algorithm plays an important role in the realization of multiplexing gain. In this paper, an improved Semi-orthogonal User Selection algorithm based on condition number is proposed. Besides, a new MIMO pre- coding scheme is designed. The proposed SUS- CN （SUS with condition number） algorithm outperforms the SUS algorithm for the selection of users with better matrix inversion property, thus a higher information rate for selected user pair is achieved. The designed MIMO precoding matrix brings benefits of the power equality at transmitted terminals, the limited dynamic range of the power over time, and a better power efficiency. The simulation results give the key insights into the im- pact of the different condition number value and users on the sum-rate capacity.

关键词： Multiple-Input Multiple-Output sumrate capacity condition number semi-orthogonaluser selection

Economic Value Evaluation of Wetland Service in Yeyahu Wetland Nature Reserve,Beijing

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Chinese Geographical Science 2011年第6期21卷 744-752页

作者： ZHU Lin CHEN Yun gong Huili JIANG Weiguo ZHAO Wenji XIAO Yanfang College of Resources Environment and Tourism Capital Normal University Beijing 100048 China CSIRO Land and Water Laboratory Canberra 2601 Australia Laboratory of Environmental Changeand Natural Disaster Beijing Normal University Beijing 100048 China）

Based on multi-source data,this paper evaluated the economic value of ecological services in the Yeyahu Wetland Nature Reserve,Beijing,*** ecological services of wetland included gas regulation,water quality im-provement,biodiversity maintenance,erosion control,water supply,recreational opportunity,raw material supply and existence *** conventional evaluation methods were used to calculate the value of eight wetland *** results showed that significant values came from biodiversity maintenance and recreational *** main reasons were as ***,Yeyahu Wetland Nature Reserve was the habitat for migrant birds,and government had payed more efforts to protect precious ***,the population is large in *** enjoyed going outside and enjoyed the natural and artificial wetland *** the same time,most people were prepared to pay for wetland *** decline of vegetation cover made the economic value of erosion control the *** the shrink of water resource and the deteriorative water quality caused the economic value of water supply *** evaluation results could help decision-makers understand the present status of the Yeyahu Wetland Nature Reserve and provide a scientific basis for strategic decision.

关键词： economic value evaluation wetland service Yeyahu Wetland Nature Reserve Beijing

HJ-1A HSI on-orbit radiometric calibration and validation research

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Science China(Technological Sciences) 2010年第11期53卷 3119-3128页

作者： GAO HaiLiang GU XingFa YU Tao gong Hui LI JiaGuo LI XiaoYing State Key Laboratory of Remote Sensing Science Jointly Sponsored by the Institute of Remote Sensing Applications of Chinese Academy of Sciences and Beijing Normal UniversityBeijing 100101China Graduate University of Chinese Academy of Sciences Beijing 100039China Center for National Spaceborne Demonstration Beijing 100101China

The calibration experiment data at Dunhuang radiometric calibration site in October, 2008 were used to achieve the on-orbit radiometric calibration for HJ-1A hyper spectral imager (HSI). Two other field experiments data were used to validate the Dunhuang calibration results. One field experiment took place in Inner-Mongolia, China in September, 2008, and the other field experiment took place in Lake Frome, Australia in February, 2009. Finally, the ‘confidence interval of calibration error’ concept was put forward for quantitatively computing the calibration coefficient error confidence interval. The results showed that the Dunhuang calibration results in 2008 had high reliability. The confidence intervals of calibration error for all HSI channels were between 2% to 12%, which could satisfy the requirement of the HSI quantitative applications.

关键词： HJ-1A hyper spectral imager(HSI) radiometric calibration validation confidence interval

Synergetic effect of FeVO_4 andα-Fe_2O_3 in Fe-V-O catalysts for liquid phase oxidation of toluene to benzaldehyde

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Chinese Chemical Letters 2012年第2期23卷 145-148页

作者： Gui Quan Zhang Xin Zhang Tao Lin Ting gong Min Qi School of Chemical Engineering Northwest UniversityXi'an 710069China

Synergistic effect of FeVO_4 withα-Fe_2O_3 was found in Fe-V-O catalyst,which was responsible for the high apparent formation rate（A.F.R.） of benzaldehyde in liquid phase oxidation of toluene by hydrogen *** synergistic effect might create VO_πspecies as active sites;moreover,it improved the reducibility and the reactivity of Fe-V-O *** order to gain the high A.F.R. of benzaldehyde,the catalyst should have the moderate reducibihty.

关键词： Liquid oxidation Synergistic effect Toluene Benzaldehyde FeVO_4 α-Fe_2O_3

Subdiffraction optical manipulation of the charge state of nitrogen vacancy center in diamond

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Light(Science & Applications) 2015年第1期4卷 554-561页

作者： Xiangdong Chen Changling Zou Zhaojun gong Chunhua Dong Guangcan Guo Fangwen Sun Key Lab of Quantum Information University of Science and Technology of ChinaHefei 230026China Synergetic Innovation Center of Quantum Information and Quantum Physics University of Science and Technology of ChinaHefei 230026China

As a potential candidate for quantum computation and metrology,the nitrogen vacancy(NV)center in diamond presents both challenges and opportunities resulting from charge-state *** utilizing different lasers for the photon-induced charge-state conversion,we achieved subdiffraction charge-state *** charge-state depletion(CSD)microscopy resolution was improved to 4.1 nm by optimizing the laser pulse ***,the electron spin-state dynamics of adjacent NV centers were selectively detected via the *** experimental results demonstrated that the CSD can improve the spatial resolution of the measurement of NV centers for nanoscale sensing and quantum information.

关键词： charge state NV center photon ionization super-resolution microscopy