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Highly Efficient Organic Ultraviolet Photodetectors Based on Re(I) Complexes

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Chemical Research in Chinese Universities 2012年第3期28卷 503-506页

作者： liU Chun-bo WANG Long liU Min li Chuan-bi li Chun-mei CHE guang-bo SU bin College of Chemistry Jilin Normal UniversitySiping 136000P.R.China College of Environmental Engineering Jilin Normal UniversitySiping 136000P.R.China

High response organic ultraviolet photodetectors（UV-PDs） were demonstrated with 4,4＇,4”- tris[3-methyl-pheny（phenyl）amino]triphenylamine（m-MTDATA） and two Re（Ⅰ） complexes, （bathocuproine）- Re（CO）3CI（Re-BCP） and （bathophenanthroline）Re（CO）3Cl（Re-Bphen） to act as the electron donor and acceptor, re- spectively. UV-PDs have the configuration of indium tin oxide（ITO）/m-MTDATA（25 nm）/m-MTDATA：Re-complex （25-35 nm）/Re-complex（20 nm）/liF（l nm）/Al（200 nm） with different blend layer thicknesses of 25, 30 and 35 nm. The optimized PD based on Re-Bphen offers a corrected-dark photocurrent up to 760μA/cm^2 at -10 V, corresponding to a response of 310 mA/W which is among the best values reported for organic UV-PDs. Excellent electron transport ability makes for such high photo-to-electron conversion.

关键词： Organic ultraviolet photodetector Re(Ⅰ) complex High electron transport ability

linear Arboricity of Outer-1-Planar Graphs

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Journal of the Operations Research Society of China 2021年第1期9卷 181-193页

作者： Xin Zhang bi li School of Mathematics and Statistics Xidian UniversityXi’an 710071China

A graph is outer-1-planar if it can be drawn in the plane so that all vertices are on the outer face and each edge is crossed at most *** et al.(Edge covering pseudo-outerplanar graphs with forests,Discrete Math 312:2788-2799,2012;MR2945171)proved that the linear arboricity of every outer-1-planar graph with maximum degree△is exactly[△/2] provided that△=3or△≥5 and claimed that there are outer-1-planar graphs with maximum degree △=4 and linear arboricity[[(O+1)/2]=*** is shown in this paper that the linear arboricity of every outer-1-planar graph with maximum degree 4 is exactly 2 provided that it admits an outer-1-planar drawing with crossing distance at least 1 and crossing width at least 2,and moreover,none of the above constraints on the crossing distance and Crossing width can be removed..Besides,a polynomial-time algorithm for constructing a path-2-coloring(i.e.,an edge 2-coloring such that each color class induces a linear forest,a disjoint union of paths)of such an outer-1-planar drawing is given.

关键词： Outer-1-planar graph Crossing linear arboricity Polynomial-time algorithm

Topotactic reduction of layered double hydroxides for atomically thick two-dimensional non-noble-metal alloy

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Nano Research 2017年第9期10卷 2988-2997页

作者： Pengsong li Qixian Xie lirong Zheng guang Feng Yingjie li Zhao Cai Yongmin bi Yaping li Yun Kuang Xiaoming Sun Xue Duan State Key Laboratory of Chemical Resource Engineering Beijing University of Chemical Technology Beijing 100029 China College of Energy Beijing University of Chemical Technology Beijing 100029 China Beijing Advanced Innovation Centre for Soft Matter Science and Engineering Beijing University of Chemical Technology Beijing 100029 China Institute of High Energy Physics Chinese Academy of Sciences Beijing 100049 China

Layered double hydroxides (LDHs) have been widely used as catalysts owing to their tunable structure and atomic dispersion of high-valence metal ions; however, limited tunability of electronic structure and valence states have hindered further improvement in their catalytic performance. Herein, we reduced ultrathin LDH precursors in situ and topotactically converted them to atomically thick (~2 nm) two-dimensional (2D) multi-metallic, single crystalline alloy nanosheets with highly tunable metallic compositions. The as-obtained alloy nanosheets not only maintained the vertically aligned ultrathin 2D structure, but also inherited the atomic dispersion of the minor metallic compositions of the LDH precursors, even though the atomic percentage was higher than 20%, which is far beyond the reported percentages for single-atom dispersions (usually less than 0.1%). Besides, surface engineering of the alloy nanosheets can finely tune the surface electronic structure for catalytic applications. Such in situ topotactic conversion strategy has introduced a novel approach for atomically dispersed alloy nanostructures and reinforced the synthetic methodology for ultrathin 2D metal-based catalysts.

关键词： atomic thickness two-dimensional (2D) nanosheets non-noble-metal alloy atomic dispersion catalysis

RP-HPLC Determination and Pharmacokinetic Comparison of Cinnamic Acid in Rat Plasma After Administration of Di-Gu-Pi Decoction and Pure Cinnamic Acid

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Chemical Research in Chinese Universities 2006年第1期22卷 56-60页

作者： li Kang bi Kai-shun Department of Pharmacy Shenzhen Hospital Beijing University Shenzhen 518036 P.R. China College of Pharmacy Shenyang Pharmaceutical University Shenyang 110016 P.R. China

A sensitive, simple, and accurate method was developed for the determination and pharmacokinetic comparison of cinnamic acid in rat plasma after the administration of a Traditional Chinese Medicinal preparation, Di-Gu-Pi decoction, and pure cinnamic acid using RP-HPLC. Di-Gu-Pi was extracted with 5% aqueous sodium bicarbonate, which was followed by purification with ion exchange column chromatography. The plasma samples taken from rats were deproteinized with methanol. The reversed-phase （HPLC） system with a Diamonsil C18 column and methanol-acetonitfile-water （8： 32： 60, volume ratio）（adjusted to pH = 3.0 with glacial acetic acid） as the mobile phase was employed for the separation of cinnamic acid in the plasma samples. The detection was set at 272 nm and 3-（p-fluoro-phenyl）-2-propenoic acid was chosen as the internal standard. The calibration curve was linear in a range from 0. 10 to 25.0μg/mL （R2 = 0. 9988, n = 9）. The precision was 3.42%-10. 10%; the between-day precision was 2. 84%-8.91% ; the accuracy was - 1.51%-1.26% ; the mean recovery was 99. 9%. The method was found to be sensitive, simple, accurate and appropriate for the determination of cinnamic acid.

关键词： Di-Gu-Pi decoction Cinnamic Acid Pharmacokinetics RP-HPLC

An Optimal Content Caching Framework for Utility Maximization

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Tsinghua Science and Technology 2016年第4期21卷 374-384页

作者： Ran bi Yingshu li Xu Zheng Department of Computer Science Dalian University of Technology Department of Computer Science Georgia State University Department of Computer Science Harbin Institute of Technology

For desirable quality of service, content providers aim at covering content requests by large network caches. Content caching has been considered as a fundamental module in network architecture. There exist few studies on the optimization of content caching. Most existing works focus on the design of content measurement, and the cached content is replaced by a new one based on the given metric. Therefore, the performance for service provision with multiple levels is decreased. This paper investigates the problem of finding optimal timer for each content. According to the given timer, the caching policies determine whether to cache a content and which existing content should be replaced, when a content miss occurs. Aiming to maximize the aggregate utility with capacity constraint, this problem is formalized as an integer optimization problem. A linear programming based approximation algorithm is proposed, and the approximation ratio is proved. Furthermore, the problem of content caching with relaxed constraints is given. A Lagrange multiplier based approximation algorithm with polynomial time complexity is proposed. Experimental results show that the proposed algorithms have better performance.

关键词： content caching utility maximization integer optimization approximation algorithm

Short-time Lv transform and its application for non-linear FM signal detection

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Journal of Systems Engineering and Electronics 2015年第6期26卷 1159-1168页

作者： Shan Luo Xiumei li Guoan bi School of Aeronautics and Astronautics University of Electronic Science and Technology of China School of Information Science and Engineering Hangzhou Normal University School of Electrical and Electronic Engineering Nanyang Technological University

A new time-frequency transform, known as short-time Lv transform （STLVT）, is proposed by applying the inverse Lv distribution to process consecutive segments of long data sequence. Compared with other time-frequency representations, the STLVT is able to achieve better energy concentration in the time-frequency domain for signals containing multiple linear and/or non-linear frequency modulated components. The merits of the STLVT are demonstrated in terms of the effects of window length and overlap length between adjacent segments on signal energy concentration in the time-frequency domain, and the required computational complexity. An application on the spectrum sensing for cognitive ratio （CR） by using a joint use of the STLVT and Hough transform （HT） is proposed and simulated.

关键词： Lv distribution time-frequency transform frequencymodulated signal spectrum sensing.

Multi-hazard joint probability distribution model for wind speed,wind direction and rain intensity

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Science China(Technological Sciences) 2023年第2期66卷 336-345页

作者： bi WenZhe TIAN li li Chao ZHANG SiYao School of Civil Engineering Shandong UniversityJinan 250061China Faculty of Infrastructure Engineering Dalian University of TechnologyDalian 116024China

Multiple disasters such as strong wind and torrential rain pose great threats to civil ***,most existing studies ignored the dependence structure between them,as well as the effect of wind *** the dimension of the engineering sector,this paper introduces the vine copula to model the joint probability distribution(JPD)of wind speed,wind direction and rain intensity based on the field data in Yangjiang,China during 1971–***,the profiles of wind and rain in the studied area are statistically analyzed,and the original rainfall amounts are converted into short-term rain ***,the marginal distributions of individual variables and their pairwise dependence structures are built,followed by the development of the trivariate joint distribution *** results show that the constructed vine copula-based model can well characterize the dependence structure between wind speed,wind direction and rain ***,the JPD characteristics of wind speed and rain intensity show significant variations depending on wind direction,thus the effect of wind direction cannot be *** proposed JPD model will be conducive for reasonable and precise performance assessment of structures subjected to multiple hazards of wind and rain actions.

关键词： joint probability distribution wind speed rain intensity wind direction vine copulas directionality effects

Defect Formation Mechanisms in Selective Laser Melting:A Review

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Chinese Journal of Mechanical Engineering 2017年第3期30卷 515-527页

作者： bi Zhang Yongtao li Qian Bai Key Laboratory for Precision and Non-traditional Machining Technology of Ministry of Education Dalian University of Technology Department of Mechanical Engineering University of Connecticut

Defect formation is a common problem in selective laser melting （SLM）. This paper provides a review of defect formation mechanisms in SLM. It sum- marizes the recent research outcomes on defect findings and classification, analyzes formation mechanisms of the common defects, such as porosities, incomplete fusion holes, and cracks. The paper discusses the effect of the process parameters on defect formation and the impact of defect formation on the mechanical properties of a fabri- cated part. Based on the discussion, the paper proposes strategies for defect suppression and control in SLM.

关键词： Selective laser melting Process parameters -Defect Mechanical properties

Non-Metric CCD Camera Calibration Algorithm in a Digital Photogrammetry System

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Journal of China University of Mining and Technology 2006年第2期16卷 119-122页

作者： YANG Hua-chao DENG Ka-zhong ZHANG Shu-bi GUO guang-li ZHOU Ming School of Environment and Spatial lnformatics China University of Mining ＆ Technology Xuzhou Jiangsu 221008 China

Camera calibration is a critical process in photogrammetry and a necessary step to acquire 3D information from a 2D image. In this paper, a flexible approach for CCD camera calibration using 2D direct linear transformation （DLT） and bundle adjustment is proposed. The proposed approach assumes that the camera interior orientation elements are known, and addresses a new closed form solution in planar object space based on homogenous coordinate representation and matrix factorization. Homogeneous coordinate representation offers a direct matrix correspondence between the parameters of the 2D DLT and the collinearity equation. The matrix factorization starts by recovering the elements of the rotation matrix and then solving for the camera position with the collinearity equation. Camera calibration with high precision is addressed by bundle adjustment using the initial values of the camera orientation elements. The results show that the calibration precision of principal point and focal length is about 0.2 and 0.3 pixels respectivelv, which can meet the requirements of close-range photogrammetry with high accuracy.

关键词： direct linear transformation collinearity equation bundle adjustment camera calibration Hough transformation