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| 1 | Three-dimensional analysis of micro defect morphologies in cement-based materials using focused ion beam tomography显示文摘Although there has been much research of cracks of the cement-based materials using optical and electron microscopy two-dimensional(2D) imaging methods,the real three-dimensional(3D) crack shapes have not previously been revealed.Thanks to the focused ion beam(FIB) tomography and the follow-up image processing,two 3D subsurface cracks and a cluster of inner cracks were picked out and discussed in this research.It was found that the subsurface crack(its length is about 15 μm,width about 1 5 μm,and opening about 1 μm) was much larger than the inner crack(its length and width are about 1 5 μm,opening is from 200 nm to 1 μm),which arose from the sample preparation process.Besides,it was revealed that most of the inner cracks were in the form of clusters. | WAN KeShu SUN Wei TANG ChunKai RONG ZhiDan | 2012 | Science China(Technological Sciences)2012，55，6： | 1 |
| 2 | A low-energy ion spectrometer with half-space entrance for three-axis stabilized spacecraft显示文摘A low-energy ion spectrometer(LEIS) for use aboard three-axis stabilized spacecraft has been developed to measure ion energy per charge distribution in three-dimensional space with good energy-, angular-and temporal-resolutions. For the standard top-hat electrostatic analyzer used widely in space plasma detection, three-axis stabilized spacecraft makes it difficult to obtain complete coverage of all possible ion arrival directions. We have designed angular scanning deflectors supplementing to a cylindrically symmetric top-hat electrostatic analyzer to provide a half-space field of view as 360°×90°(–45°–+45°), and fabricated the LEIS flight model for detecting magnetospheric ions in geosynchronous orbit. The performance of this payload has been evaluated in detail by a series of simulation and environmental tests, and the payload has also been calibrated through laboratory experiments using a low-energy ion source. The results show that capabilities of the LEIS payload are in accordance with the requirements of a magnetospheric mission. | HU RenXiang SHAN Xu YUAN GuangYuan WANG ShuWen ZHANG WeiHang QI Wei CAO Zhe LI YiRen CHEN ManMing YANG XiaoPing WANG Bo SHAO SiPei LI Feng ZHONG XiaoQing FAN Dan HAO XinJun FENG ChangQing SU ZhenPeng SHEN ChengLong LI Xin DAI GuYue QIU BingLin PAN ZongHao LIU Kai XU ChunKai LIU ShuBin AN Qi ZHANG TieLong WANG YuMing CHEN XiangJun | 2019 | Science China(Technological Sciences)2019，62，6： | 1 |
| 3 | Catalytic Com- bustion of Methane over PdO Supported on Mg-Modified Alu- mina显示文摘 | Yang Lefu Shi Chunkai He Xiang'e | 2002 | ApplCatal B2002，38，2： | 1 |
| 4 | High temperature performance and low frequency noise characteristics of A1GaN/GaN/A1GaN double heterostructure MOS heterostructure field effect transistors with photochemical vapor deposition SIO2 layer 显示文摘 | Wang Chunkai Chang Shooujinn Su Yan-kuin | 2005 | Jpn J Appl Phys2005，44，4： | 1 |
| 5 | Effect of a second metal (Y, K, Ca, Mn or Cu) addition on the carbon dioxide reforming of methane over nanostructured palladium catalysts显示文摘 | Chunkai Shi Peng Zhang | 2011 | Applied Catalysis B Environmental2011，，： | 1 |
| 6 | Theoretical and experimental study of 3-D initial fracture and its significance to faulting显示文摘The experimental results of 3-D fracture under compression are introduced in brief and the theory of stress criterion of 3-D fracture is studied.Methods to imitate initial fractures are developed.It is pointed that there are important defects in the extreme value(EV)method ever proposed by Palaniswamy and Knauss. The major defect lies in that only two Euler angles(2EA)are considered,but another one is neglected.If the variation of all the three Euler angles(3EA)are considered,one can get better result which is consistent with the observation of faulting that extends on curved surfaces but not on planes.The method of evaluating maximal normal stress direction vector(NSDV)is proposed and further proved to be equivalent to the 3EA method.It is proved that the NSDV method can be further optimized to the method of composition of the first principal differential plane(CFPDP).The results from CFPDP method can fit the curved surfaces of initial growth observed in the experiments of 3-D fracture.The CFPDP method can also be used to interpret the 3-D fractures of the slipping section between the asperities in the buried fault plane that is modeled as ellipse crack.The results of 3-D fracture can be applied to interpreting the related problems of faulting including the mechanism of a lot of shatter rocks with different dimensions,the cause of earthquakes occurred at the edge of plate under low shear stress,and the mechanism of anisotropy caused by the extensive dilatancy anisotropy(EDA)cracks. | Shiyu Li Taiming He Chunkai Teng Xuyao Zheng Kuksenko Viktor | 2011 | Earthquake Science2011，24，3： | 1 |
| 7 | Research of Detection Algorithm for Time Series Abnormal Subsequence显示文摘The recent advancements in sensor technology have made it possible to collect enormous amounts of data in real time.How to find out unusual pattern from time series data plays a very important role in data mining.In this paper,we focus on the abnormal subsequence detection.The original definition of discord subsequences is defective for some kind of time series,in this paper we give a more robust definition which is based on the k nearest neighbors.We also donate a novel method for time series representation,it has better performance than traditional methods(like PAA/SAX)to represent the characteristic of some special time series.To speed up the process of abnormal subsequence detection,we used the clustering method to optimize the outer loop ordering and early abandon subsequence which is impossible to be abnormal.The experiment results validate that the algorithm is correct and has a high efficiency. | Chunkai Zhang Haodong Liu Ao Yin | 2017 | 国际计算机前沿大会会议论文集2017，，1： | 0 |
| 8 | A Classification Method of Imbalanced Data Base on PSO Algorithm显示文摘In order to improve the performance of the resampling algorithm in imbalanced data learning and the optimal combination of the weight coefficients of the base classifiers in the ensemble classification algorithm,a new algorithm based on particle swarm optimization(PSO)is proposed.In traditional sampling method,sampling rate is often set artificially.This would make the final classification can’t get a optimal solution.By using the particle swarm optimization algorithm,the sampling rate of the boundary samples and the safety samples are optimized to obtain the optimal over sampling rate self-adaptivly,the weekness of setting sampling rate of traditional method would be overcome. | Junru Lu Chunkai Zhang Fengxing Shi | 2016 | 国际计算机前沿大会会议论文集2016，，2： | 0 |
| 9 | Outsourced Privacy-Preserving Anomaly Detection in Time Series of Multi-Party显示文摘Anomaly detection has practical significance for finding unusual patterns in time series.However,most existing algorithms may lose some important information in time series presentation and have high time complexity.Another problem is that privacy-preserving was not taken into account in these algorithms.In this paper,we propose a new data structure named Interval Hash Table(IHTable)to capture more original information of time series and design a fast anomaly detection algorithm based on Interval Hash Table(ADIHT).The key insight of ADIHT is distributions of normal subsequences are always similar while distributions of anomaly subsequences are different and random by contrast.Furthermore,to make our proposed algorithm fit for anomaly detection under multiple participation,we propose a privacy-preserving anomaly detection scheme named OP-ADIHT based on ADIHT and homomorphic encryption.Compared with existing anomaly detection schemes with privacy-preserving,OP-ADIHT needs less communication cost and calculation cost.Security analysis of different circumstances also shows that OP-ADIHT will not leak the privacy information of participants.Extensive experiments results show that ADIHT can outperform most anomaly detection algorithms and perform close to the best results in terms of AUC-ROC,and ADIHT needs the least time. | Chunkai Zhang Wei Zuo Peng Yang Ye Li Xuan Wang | 2022 | China Communications2022，19，2： | 0 |
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