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A wide-field and high-resolution lensless compound eye microsystem for real-time target motion perception

Microsystems & Nanoengineering 2022年第4期8卷 199-207页

作者： Li zhang Haiyang zhan Xinyuan Liu Fei Xing zheng You Department of Precision Instrument Tsinghua UniversityBeijing 100084China State Key Laboratory of Precision Measurement Technology and Instrument Tsinghua UniversityBeijing 100084China Beijing Advanced Innovation Center for Integrated Circuits Beijing 100084China

Optical measurement systems suffer from a fundamental tradeoff between the field of view(FOV),the resolution and the update rate.A compound eye has the advantages of a wide FOV,high update rate and high sensitivity to motion,providing inspiration for breaking through the constraint and realizing high-performance optical ***,most existing studies on artificial compound eyes are limited by complex structure and low resolution,and they focus on imaging instead of precise ***,a high-performance lensless compound eye microsystem is developed to realize target motion perception through precise and fast orientation *** microsystem splices multiple sub-FOVs formed by long-focal subeyes,images targets distributed in a panoramic range into a single multiplexing image sensor,and codes the subeye aperture array for distinguishing the targets from different sub-FOVs.A wide-field and high resolution are simultaneously realized in a simple and easy-to-manufacture microelectromechanical system(MEMS)aperture ***,based on the electronic rolling shutter technique of the image sensor,a hyperframe update rate is achieved by the precise measurement of multiple time-shifted spots of one *** microsystem achieves an orientation measurement accuracy of 0.0023°(3σ)in the x direction and 0.0028°(3σ)in the y direction in a cone FOV of 120°with an update rate~20 times higher than the frame *** study provides a promising approach for achieving optical measurements with comprehensive high performance and may have great significance in various applications,such as vision-controlled directional navigation and high-dynamic target tracking,formation and obstacle avoidance of unmanned aerial vehicles.

关键词： precise resolution compound

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An optimized texture-by-numbers synthesis method and its visual applications

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Science China(Information Sciences) 2013年第5期56卷 50-63页

作者： FAN Jing SHI Xiaoying ZHOU zhan TANG ying School of Computer Science and Technology Zhejiang University of Technology Key Laboratory of Visual Media Intelligent Processing Technology of Zhejiang Province School of Information Engineering Zhejiang University of Technology

The framework of texture-by-numbers(TBN) synthesizes images of global-varying patterns with intuitive user *** TBN synthesis methods have difficulties in achieving high-quality synthesis results and efficiency *** paper proposes a fast TBN synthesis method based on texture optimization,which uses global optimization to solve the controllable non-homogeneous texture synthesis *** algorithm produces high quality synthesis results by combining texture optimization into TBN framework with two *** initialization process is adopted to generate the initial output of the global optimization algorithm,which speeds up the algorithm’s convergence rate and enhances synthesis *** distance metrics to measure image similarities are specifically designed for different images to better match human visual perception for structural patterns and a user study is conducted to verify the effectiveness of the *** further improve the synthesis speed,the algorithm is entirely implemented on GPU based on CUDA *** optimized TBN method is applied to various visual applications including not only traditional TBN applications,but also image in-painting and texture-based flow *** experimental results show that our method synthesizes images of higher or comparable qualities with higher efficiency than other state-of-art synthesis methods.

关键词： texture-by-number texture optimization feature synthesis CUDA

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NUMERICAL PREDICTION OF BLADE FREQUENCY NOISE OF CAVITATING PROPELLER

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Journal of Hydrodynamics 2012年第3期24卷 371-377页

作者： YE Jin-ming XIONG ying LI Fang WANG zhan-zhi College of Naval Architecture and Power Naval University of Engineering Wuhan 430033 China

The blade frequency noise of a cavitating propeller in a uniform flow is analyzed in the time domain. The unsteady loading （of a dipole source） and the sheet cavity volume （of a monopole source） on the propeller surface are calculated by a potential-based surface panel method. Then the time-dependent pressure and the cavity volume data are used as the input for the Fowcs Williams-Hawkings formulation to predict the acoustics pressure. The integration of the noise source is performed over the true blade surface rather than the ideal blade surface without thickness. The noise characteristics of the cavitating propeller are discussed. With the sheet cavitation, the thickness （cavitation） noise is larger than the loading noise and is the dominant noise source. The noise directivity is not as clear as that of the noise under a non-cavitation condition. The cavitation noise is attenuated more slowly than the non-cavitation noise.

关键词： propeller surface panel method cavitation noise time domain

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Cellular response to titanium discs coated with polyelectrolyte multilayer films

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International Journal of Minerals,Metallurgy and Materials 2014年第9期21卷 925-933页

作者： Jing zhan Qiao-jie Luo ying Huang Xiao-dong Li Department of Stomatology Sir Run Run Shaw Hospital College of Medicine Zhejiang University Department of Oral and Maxillofacial Surgery the Affiliated Stomatology Hospital College of Medicine Zhejiang University

The purpose of this study was to investigate the effects ofpolyelectrolyte multilayer （PEM） coatings on the biological behavior of titanium （Ti） substrates. Collagen type I/hyaluronic acid （Col/HA） and chitosan/hyaluronic acid （Chi/HA） multilayer PEM coatings were introduced onto Ti substrates using layer-by-layer assembly. Contact angle instruments and quartz crystal microbalance were used for film characterization. The results obtained showed that both Col/HA and Chi/HA surfaces had high hydrophilicity and promoted cell adhesion in MC3T3-E1 pre-osteoblast and human gingival fibroblast cells. In addition, the synthesis of function-related proteins and gene expression levels in both MC3T3-E1 and fibroblast cells was higher for the Col/HA coating compared with the Chi/HA coating, indicating better cellular response to the Col/HA coating.

关键词： titanium surface modification polyelectrolytes multilayer films cellular response

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Effect of flow control mold on flow field during high-speed continuous casting

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Advances in Manufacturing 2017年第3期5卷 271-278页

作者： zhan Yu zheng-Qiang zhang Zhong-Ming Ren Nanjing Iron and Steel Co. Ltd. Nanjing 210035 JiangsuPeople's Republic of China Shanghai Key Laboratory of Modem Metallurgy andMaterials Processing Shanghai University Shanghai 200072 People's Republic of China

An experimental mold was built to study the flow in a flow control mold under high speed continuous casting. The effect of the magnetic field on the flow was investigated using mercury. The results show that the magnetic field can not only dampen the flow of liquid metal but also change its direction, and then redistribute the flow in the mold. When maintaining a constant distance between magnets, the fluctuation of the free surface is dampened because of the increasing magnetic flux density. The flow at the free surface is improved, and the penetration depth of the downward stream is reduced. The decrease in the dis- tance between magnets promotes the brake effect and the flow is dampened in the upper eddy.

关键词： High-speed continuous casting Flow control(FC) mold Flow of liquid metal ·Electromagnetic brake

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Biologically inspired collective construction with visual landmarks

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Journal of Zhejiang University-Science C(Computers and Electronics) 2012年第5期13卷 315-327页

作者： zheng-wei zhan Hong zhanG Yi-bin LI School of Control Science and Engineering Shandong University Jinan 250061 China Department of Computing Science University of Alberta Edmonton Alberta T6G 2E8 Canada

We describe our research in using environmental visual landmarks as the basis for completing simple robot construction *** by honeybee visual navigation behavior,a visual template mechanism is proposed in which a natural landmark serves as a visual reference or template for distance determination as well as for navigation during collective *** validate our proposed mechanism,a wall construction problem is investigated and a minimalist solution is *** results show that,using the mechanism of a visual template,a collective robotic system can successfully build the desired structure in a decentralized fashion using only local sensing and no direct *** addition,a particular variable,which defines tolerance for alignment of the structure,is found to impact the system *** decreasing the value of the variable,system performance is improved at the expense of a longer construction *** visual template mechanism is appealing in that it can use a reference point or salient object in a natural environment that is new or unexplored and it could be adapted to facilitate more complicated building tasks.

关键词： Biologically inspired Swarm robotics Collective construction Visual landmark Template

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Spatial distribution and pollution assessment of mercury in sediments of Lake Taihu,China

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Journal of Environmental Sciences 2013年第2期25卷 316-325页

作者： Chunxiao Chen Binghui zheng Xia Jiang zheng Zhao Yuzhu zhan Fengjiao Yi Jiaying Ren Beijing Normal University State Key Laboratory of EnvironmentalCriteria and Risk Assessment Chinese Research Academy of Environment Sciences Shanghai Waterway Engineering Design and Consulting Co. Ltd.

Spatial distribution patterns of total mercury （THg） in 36 surficial sediment samples representing five regions of Lake Taihu were assessed using the ArcGis geostatistical analyst module. The pollution levels of THg were also evaluated from the same five lake regions. Concentrations of THg were in a ranged of 23-168 ng/g （mean 55 ng/g） in surfical sediments, which was significantly higher than those established baseline levels of the lake. Results of THg indicated that the northern region exhibited notably higher values, the bay regions showed elevated values relative to open areas, and the lakeside regions were higher than those observed in the central area. Lake Taihu suffered moderate to high Hg pollution, and expressed clear Hg enrichment status according to monomial pollution index I geo and human activity factors. The concentrations of THg in the surficial sediments of Lake Taihu showed moderate-strong variation （coefficient of variation 52%）. Geostatistical analysis indicated a weak spatial self-correlation, suggesting the contamination of Hg in Lake Taihu is primarily the result of anthropogenic activities.

关键词： assessment geostatistics analysis mercury sediment spatial distribution

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A new method of dynamic mesh used in continuous guide vane closure of a reversible pump-turbine in generating mode

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Journal of Hydrodynamics 2019年第5期31卷 976-985页

作者： Xiu-li Mao Yuan zheng Giorgio Pavesi zhan-shan Xie College of Water Resources and Architectural Engineering Northwest A&F UniversityYangling 712100China College of Water Conservancy and Hydropower Engineering Hohai UniversityNanjing 210098China Department of Industrial Engineering University of PaduaPadovaItaly

In this paper,a new method of dynamic mesh based on two functional controls is used in the continuous guide vane closure,and the three-dimensional numerical simulation is carried out to investigate the transient flow characteristics for a Francis-type reversible pump-turbine in the turbine mode in the load regulation scenario,with the detached eddy simulation(DES)turbulent *** transient flow characteristics during the closure of the guide vanes are illustrated by analyzing the signals of the mass flow,the torque and the pressure fluctuations in the frequency and time-frequency *** is shown by the simulated results that a continuous assessment of the transient flow characteristics during the guide vane closure may be made by using the new method of the dynamic ***,the flow field analysis involves both the onset and the development of the unsteady phenomena progressively based on an organized guide vane closure *** flow pattern in the return channel maintains a relatively stable flow field before the last stage of the closure,as compared with the unstable flow field in other *** identify the unit variation under the fluid-dynamical conditions,the influence of the three-dimensional unsteady flow structures in the passage is analyzed and its evolution during this transient process is characterized by the fluid-dynamics and the spectral analysis.

关键词： Francis-type reversible turbine dynamic mesh guide vane closure flow characteristics

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An Efficient CSI Feedback Scheme for Dual-Polarized MIMO Systems Using Layered Multi-Paths Information

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China Communications 2017年第5期14卷 91-104页

作者： Feng zheng Yijian Chen Qian zhan Jie zhang Beijing Key Laboratory of Network System Architecture and Convergence Beijing University of Posts and TelecommunicationsBeijing 100876BeijingChina ZTE Corporation Shenzhen 518055China Beijing University of Posts and Telecommunications Beijing 100876China Department of Electronic and Electrical Engineering The University of SheffieldWestern BankShelffield S102TNUK

Massive MIMO is one of tile enabling technologies tbr beyond 4G and 5G systems due to its ability to provide beamforming gain and reduce interference Dual-polarized antenna is widely adopted to accommodate a large number of antenna elements in limited space. However, current CSI（channel state information） feedback schemes developed in LTE for conventional MIMO systems are not efficient enough for massive MIMO systems since the overhead increases almost linearly with the number of antenna. Moreover, the codebook for massive MIMO will be huge and difficult to design with the LTE methodology. This paper proposes a novel CSI feedback scheme named layered Multi-paths Information based CSI Feedback （LMPIF）, which can achieve higher spectrum efficiency for dual-polarized antenna system with low feedback overhead. The MIMO channel is decomposed into long term components （multipath directions and amplitudes） and short term components （multipath phases）. The relationship between the two components and the optimal precoder is derived in closed form. To reduce the overhead, different granularities in feedback time have been applied for the long term components and short term components Link and system level simulation results prove that LMPIF can improve performance considerably with low CSI feedback overhead.

关键词： communication and information system: efficient CSI feedback: channel characteristie analysis dual-polarized: massive MIMO: layered Multi-Paths information codeword model

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Clinical and genetic characteristics of Chinese hereditary nonpolyposis colorectal cancer families

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World Journal of Gastroenterology 2006年第25期12卷 4074-4077页

作者： Xu-Lin Wang ying Yuan Su-zhan zhang Shan-Rong Cai Yan-Qin Huang Qiang Jiang Shu zheng Cancer Institute the 2nd Affiliated Hospital College of Medicine Zhejiang University 88 Jie-Fang Road Hangzhou 310009 Zhejiang Province China

AIM： To analyze the clinical characteristics of Chinese hereditary nonpolyposis colorectal cancer （HNPCC） families and to screen the germline mutations of human mismatch repair genes hMLH1 and hMSH2 in the probands. METHODS： Thirty-one independent Chinese HNPCC families were collected in Zhejiang Province. All of them met Chinese HNPCC criteria. Clinical data about patient gender, site of colorectal cancer, age of onset, history of multiple colorectal cancer, associated extracolonic cancer were recorded. PCR and denaturing high performance liquid chromatography （DHPLC） were employed to screen the mutations. Sequencing analysis was used to find out the exact mutation site and characteristics of the samples showing abnormal DHPLC profiles. RESULTS： One hundred and thirty-six malignant neoplasms were found in 107 patients including 14 multiple cancers. One hundred and six of the 136 neoplasms （77.9%） were diagnosed as colorectal cancer, with an average age of onset at 48.57 ±29.00 years. Gastric cancer was the most common extracolonic cancer （10.3%） in these families. Twenty-three different sequence variations in hMLHI and hMSH2 genes were detected in these 17 families. Fifteen sequence variations were located in the exons, including 5 SNPs, 3 silent mutations, 3 missense mutations, 2 nonsense mutations and 2 frameshift mutations. The latter seven mutations seemed to be pathogenic. CONCLUSION： Germline mutations of hMLH1 and hMSH2 genes are identified in about one-third HNPCC kindreds fulfilling Chinese HNPCC criteria. Chinese HNPCC families have some particular clinical characteristics, such as a left-sided predominance, less synchronous or metachronous colorectal cancer, and frequent occurrence of gastric cancer.

关键词： Colorectal cancer Hereditary nonpolyposis DNA mutation analysis High pressure liquid Chromatography Oncogenes

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