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Universal and efficient hybrid modeling and direct slicing method for additive manufacturing processes

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Advances in Manufacturing 2024年第2期12卷 300-316页

作者： Sen-lin Wang li-chao zhang chao Cai Ming-Kai Tang Si Chen Jiang Huang Yu-Sheng Shi State Key Laboratory of Materials Processing and Die and Mould Technology Huazhong University of Science and TechnologyWuhan430074People’s Republic of China School of Machinery and Automation Wuhan University of Science and TechnologyWuhan430081People’s Republic of China

Model design and slicing contour generation in additive manufacturing(AM)data processing face challenges in terms of efficiency and scalability when stereolithography files generated by complex functionally graded structures have millions of *** paper proposes a hybrid modeling and direct slicing method for AM to efficiently construct and handle complex three-dimensional(3D)*** 3D solids,including conformal multigradient structures,were uniformly described using a small amount of data via signed distance *** hybrid representations were quickly discretized into numerous disordered directed lines using an improved marching squares *** establishing a directional HashMap to construct the topological relationship between lines,a connecting algorithm with linear time complexity is proposed to generate slicing contours for *** method replaces the mesh reconstruction and Boolean operation stages and can efficiently construct complex conformal gradient models of arbitrary topologies through hybrid ***,the time and memory consumption of direct slicing are much lower than those of previous methods when handling hybrid models with hundreds of millions of faces after mesh reconstruction.

关键词： Additive manufacturing(AM) Hybrid modeling Direct slicing Signed distance field

Behavior pattern extraction by trajectory analysis

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Frontiers of Computer Science 2011年第1期5卷 37-44页

作者： Jia Wen (12) wjyanyuan@*** chao li (1) zhang Xiong (1) Beihang Univ Sch Engn & Comp Sci Beijing 100191 Peoples R China Yanshan Univ Dept Comp Coll Informat Sci & Engn Qinhuangdao 066004 Peoples R China

Trajectory clustering and behavior pattern extraction are the foundations of research into activity perception of objects in motion. In this paper, a new framework is proposed to extract behavior patterns through trajectory analysis. Firstly, we introduce directional trimmed mean distance （DTMD）, a novel method used to measure similarity between trajectories. DTMD has the attributes of anti-noise, self-adaptation and the capability to determine the direction for each trajectory. Secondly, we use a hierarchical clustering algorithm to cluster trajectories. We design a length-weighted linkage rule to enhance the accuracy of trajectory clustering and reduce problems associated with incomplete trajectories. Thirdly, the motion model parameters are estimated for each trajectory＇s classification, and behavior patterns for trajectories are extracted. Finally, the difference between normal and abnormal behaviors can be distinguished.

关键词： trajectory clustering directional trimmedmean distance (DTMD) behavior pattern extraction

Ethical issues in penile transplantation

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Asian Journal of Andrology 2010年第6期12卷 795-800页

作者： li-chao zhang Yong-Bing Zhao Wei-lie Hu Department of Urology Guangzhou General Hospital of Guangzhou Military Command Guangzhou 510010 China

This article provides an overview of the ethical issues associated with penile transplantation, a form of composite tissue allografting. There is only one reported case of human penile transplantation, and, as such, this technique is considered to be experimental. The ethical issues at stake involve both the graft donor and the graft recipient. With regard to the recipient, there are significant concerns relating to surgical risks and benefits, informed consent, body image （including surgical expectations and outcomes） and compliance. Donor issues may include family consent and privacy, as well as graft harvesting （leaving the donor cadaver without a penis）. Many of these ethical issues can be explored during the recipient＇s assessment and consent process. Because no medium-term or long-term outcome data for this procedure exist---only one such operation has ever been performed--the burdens and ethical issues concerning penile transplantation remain unknown.

关键词： ethics penis transplantation

Improving Film Cooling Performance by Using One-Inlet and Double-Outlet Hole

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Journal of Thermal Science 2010年第5期19卷 430-437页

作者： Guang-chao li and Wei zhang Aeroengine and Energy Engineering College,Shenyang Areospace University Shenyang China 110136 Aeroengine and Energy Engineering College Shenyang Areospace University Shenyang China

The film cooling performance of a trunk-branch hole is investigated by numerical simulation in this paper. The geometry of the hole is a novel cooling concept, which controls the vortices-pair existing at the mink hole outlet using the injection of the branch hole. The trunk-branch holes require easily machinable round hole as compared to the shaped holes. The flow cases were considered at the blowing ratios of 0.5, 0.75, 1.0, 1.5 and 2.0. At the low blowing ratio of 0.5, the vortices-pair at the outlet of the trunk hole is reduced and the laterally coverage of the film is improved. At the high blowing ratio of 2.0, the vortices-pair is killed by the vortex which is produced by the injection of the branch hole. The flow rate of the two outlets becomes more significantly different when the blowing ratio increases from 0.75 to 2.0. The discharge coefficients increase 0.15 and the laterally averaged film effectiveness improve 0.2 as compared to the cylindrical holes. The optimal blowing ratios occur at M=1.0 or M= 1.5 according to the various locations downstream of the holes.

关键词： aerospace propulsion system gas turbine film cooling heat transfer

Cells derived from iPSC can be immunogenic -- Yes or No？

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Protein & Cell 2014年第1期5卷 1-3页

作者： Jiani Cao Xiaoyan li Xiao Lu chao zhang Honghao Yu Tongbiao Zhao State Key Laboratory of Reproductive Biology Institute of Zoology Chinese Academy of Sciences Beijing 100101 China

The induced pluripotent stem cells （iPSCs）, derived by ectopic expression of reprogramming factors in somatic cells, can potentially provide unlimited autologous cells for regenerative medicine. In theory, the autologous cells derived from patient iPSCs should be immune tolerant by the host without any immune rejections. However, our recent studies have found that even syn- geneic iPSC-derived cells can be immunogenic in syn- geneic hosts by using a teratoma transplantation model （Nature 474：212-215, 2011）. Recently two research groups differentiated the iPSCs into different germ lay- ers or cells, transplanted those cells to the syngeneic hosts, and evaluated the immunogenicity of those cells. Both of the two studies support our conclusions that some certain but not all tissues derived from iPSCs can be immunogenic, although they claimed either ＂negli- gible＂ or ＂lack of＂ immunogenicity in iPSC derivatives （Nature 494：100-104, 2013; Cell Stem Cell 12：407-412, 2013）. To test the immunogenicity of clinically valuable cells differentiated from human iPSCs are emergenUy required for translation of iPSC technology to clinics.

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Pore scale performance evaluation and impact factors in nitrogen huff-n-puff EOR for tight oil

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Petroleum Science 2022年第6期19卷 2932-2940页

作者： Yi-Lei Song Zhao-Jie Song Yun-Fei zhang Ze-Hui Xie li-chao zhang Dai-Gang Wang Gang Hui College of Carbon Neutral Energy State Key Laboratory of Petroleum Resources and Prospecting and Unconventional Petroleum Research InstituteChina University of Petroleum-BeijingBeijing102249China

Nitrogen huff-n-puff(N_(2)HnP) appears to be an economical and high-efficiency enhanced oil recovery(EOR) technique for tight oil *** is however a lack of understanding of the pore-level EOR performance of N2HnP under tight reservoir *** this work,a non-magnetic reactor was created and combined with a nuclear magnetic resonance(NMR) device for real-time monitoring of oil distribution in the HnP experiment.N_(2)HnP experiments were then performed in a tight sandstone core sample at a temperature of 353 K and an injection pressure≥ 24 *** pore-level oil distribution under reservoir conditions was monitored and the EOR performance of N2HnP in specific pores was *** pore throat structures of the core sample and the phase behavior of the N_(2)-Oil system were analyzed to elucidate the EOR mechanism of N_(2)*** oil recovery factor of 37.52% can be achieved after four cycles,which proves the EOR potential of N_(2)HnP for tight *** highest recoveries after N_(2)HnP are obtained in the large pores,followed by the medium pores,the small pores,and finally the micro *** in soaking time and injection pressure resulted in slight and pronounced increases in oil recovery,respectively,both of which are mainly reflected in the first ***,increasing the soaking time only slightly improves the cumulative oil recovery in the small pores while increasing the injection pressure significantly improves the cumulative oil recovery in the small,medium,and large pores ***,variations in both injection pressure and soaking time have a negligible effect on the cumulative oil recovery of the micro pores.

关键词： Tight oil reservoirs N_(2)huff-n-puff Pore-level production characteristics Impact factors Nuclear magnetic resonance

liquid crystal depolarizer based on photoalignment technology

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Photonics Research 2016年第2期4卷 70-73页

作者： Bing-Yan Wei Peng Chen Shi-Jun Ge li-chao zhang Wei Hu Yan-Qing Lu National Laboratory of Solid State Microstructures Collaborative Innovation Center of Advanced Microstructures and College of Engineering and Applied Sciences Nanjing University Thorlabs China

We propose a depolarizer based on the principle of a collection of half-wave plates with randomly distributed optic axes. The design is demonstrated by means of dynamically photopatterning liquid crystal into randomly aligned homogeneous domains. We characterize the liquid crystal depolarizer for 1550 nm and C-band(1520–1610 nm). A degree of polarization of less than 5% is obtained for any linearly polarized light. This study provides a practical candidate for high-performance depolarizers.

关键词： DOP liquid crystal depolarizer based on photoalignment technology

A Review on Thermal Management of li-ion Battery:from Small-Scale Battery Module to Large-Scale Electrochemical Energy Storage Power Station

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Journal of Thermal Science 2025年第1期34卷 1-23页

作者： CHEN Zhifeng JIA li YIN liaofei DANG chao REN Honglei zhang Zhiqiang Beijing Key Laboratory of Flow and Heat Transfer of Phase Changing in Micro and Small Scale School of MechanicalElectronic and Control EngineeringBeijing Jiaotong University

li-ion battery is an essential component and energy storage unit for the evolution of electric vehicles and energy storage technology in the ***,in order to cope with the temperature sensitivity of li-ion battery and maintain li-ion battery safe operation,it is of great necessary to adopt an appropriate battery thermal management system(BTMS).In this paper,the current main BTM strategies and research hotspots were discussed from two aspects:small-scale battery module and large-scale electrochemical energy storage power station(EESPS).The practical application situation,advantages and disadvantages,and the future development trend of each heat dissipation method(air,liquid,PCM,heat pipe,hybrid cooling) were described in *** them,the air cooling and liquid cooling were reviewed in-depth based on the engineering *** PCM,heat pipe and hybrid cooling were reviewed extensively based on the latest *** research provides a comprehensive understanding for the BTMS in all scales.

关键词： battery thermal management cooling methods large-scale electrochemical energy storage power station small-scale battery module

Spring Cold Bias of SST and Minimal Wind Mixing in the Equatorial Pacific Cold Tongue

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Atmospheric and Oceanic Science Letters 2010年第6期3卷 342-346页

作者： liN Peng-Fei liU Hai-Long li chao zhang Xue-Hong State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics Institute of AtmosphericPhysics Chinese Academy of Sciences Beijing 100029 China

The authors investigate the relationship between bias in simulated sea surface temperature （SST） in the equatorial eastern Pacific cold tongue during the boreal spring as simulated by an oceanic general circulation model （OGCM） and minimal wind mixing （MWM） at the surface. The cold bias of simulated SST is the greatest during the boreal spring, at approximately 3℃. A sensi- tivity experiment reducing MWM by one order of magnitude greatly alleviates cold biases, especially in March-April. The decrease in bias is primarily due to weakened vertical mixing, which preserves heat in the uppermost layer and results in warmer simulated SST. The reduction in vertical mixing also leads to a weak westward current in the upper layer, which further contributes to SST warming. These findings imply that there are large uncertainties about simple model parameters such as MWM at the oceanic surface.

关键词： cold biases the equatorial Pacific cold tongue the minimal wind mixing