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ON THE COLliSION DETECTION PROBLEM OF TWO MOVING OBJECTS DESCRIBED BY ALGEBRAIC SETS

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Journal of Systems Science & Complexity 2007年第1期20卷 108-118页

作者： Shurong li Chunwang hou College of Information and Controlling Engineering University of Petroleum (East China) Dongying 257061 China.

In this paper, the collision problem of two moving objects is investigated. The objects are described by two algebraic sets （ellipses or circles in the paper）. The collision problem discussed involves both static and dynamic case. The static case is that each object moves with known velocity. We use nonlinear programming to decide whether the objects collide. The dynamic case is that each object is controlled by a constraint external force which can be regulated online. For the dynamic case, the collision problem can be modelled as a Minmax problem which can be solved by using differential games. If collision occurs, the time and place of the first collision are given. The moving trajectories are provided in the paper.

关键词： Differential games mathematical mechanization moving object collision optimization.

The Folded(2D+1)-cube and Its Uniform Posets

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Acta Mathematicae Applicatae Sinica 2018年第2期34卷 281-292页

作者： li-hang hou BO hou Suo-gang GAO College of Mathematics and Information Science Hebei Normal University

Let F denote the folded （2D ＋ 1）-cube with vertex set X and diameter D ≥ 3. Fix x∈ X. We first define a partial order ≤ on X as follows. For y,z ∈ X let y ≤ z whenever （x,y）＋（y,z） =- （x, z）. Let R （resp. L） denote the raising matrix （resp. lowering matrix） of P. Next we show that there exists a certain linear dependency among RL2, LRL, L2R and L for each given Q-polynomial structure of F. Finally, we determine whether the above linear dependency structure gives this poser a uniform structure or strongly uniform structure.

关键词： distance-regular graph the folded (2D + 1)-cube uniform poset

Reverse genetics systems for SARS-CoV-2:Development and applications

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Virologica Sinica 2023年第6期38卷 837-850页

作者： hou-li Cai Yao-Wei Huang Department of Veterinary Medicine Zhejiang UniversityHangzhou310058China State Key Laboratory for Animal Disease Control and Prevention South China Agricultural UniversityGuangzhou510642China Guangdong Laboratory for lingnan Modern Agriculture College of Veterinary MedicineSouth China Agricultural UniversityGuangzhou510642China

The recent emergence of severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)caused serious harm to human health and struck a blow to global economic *** on SARS-CoV-2 has greatly benefited from the use of reverse genetics systems,which have been established to artificially manipulate the viral genome,generating recombinant and reporter infectious viruses or biosafety level 2(BSL-2)-adapted non-infectious replicons with desired *** tools have been instrumental in studying the molecular biological characteristics of the virus,investigating antiviral therapeutics,and facilitating the development of attenuated vaccine ***,we review the construction strategies,development,and applications of reverse genetics systems for SARS-CoV-2,which may be applied to other CoVs as well.

关键词： SARS-CoV-2 Reverse genetics systems Infectious clones Replicons live attenuated vaccines

Evaluation on Fatigue Performance and Fracture Mechanism of Laser Welded TWIP Steel Joint Based on Evolution of Microstructure and Micromechanical Properties

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Journal of Iron and Steel Research International 2016年第7期23卷 677-684页

作者： li-li MA Ying-hui WEI li-feng hou Chun-li GUO College of Materials Science and Engineering Taiyuan University of Technology Taiyuan 030024Shanxi China Shanxi Institute of Technology Yangquan 045000 Shanxi China

The fatigue performance and fracture mechanism of laser welded twinning induced plasticity（TWIP）steel joint were investigated experimentally based on the evolution of microstructure and micromechanical *** optical microscopy was used to analyze the evolution of *** variation of composition and phase structure of fusion zone were detected by energy dispersive X-ray and X-ray diffraction *** micromechanical behaviors of the various zones were characterized using *** static tensile test and high cycle fatigue test were performed to evaluate the mechanical properties of welded joint and base *** microstructures,tensile properties and fatigue strength of base metal as well as welded metal were *** fatigue fracture surfaces of base metal and welded joint were observed by means of scanning electron microscopy,in order to identify fatigue crack initiation sites and propagation ***,the fatigue fracture characteristics and mechanisms for the laser welded TWIP steel joints were analyzed.

关键词： TWIP steel laser welding microstructure high cycle fatigue fatigue performance fatigue fracture mechanism

SiC-Si-ZrSiO_4 Multiphase Oxidation Protective Coating for Carbon/Carbon Composites

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Journal of Materials Science & Technology 2008年第6期24卷 941-944页

作者： Yulei ZHANG Hejun li Qiangang FU Kezhi li Dangshe hou C/C Composites Technology Research Center Laboratory of Superhigh Temperature Composites Northwestern Polytechnical University Xi/an 710072 China

In order to improve the anti-oxidation property of carbon/carbon （C/C） composites, a novel SiC-Si-ZrSiO4 multiphase oxidation protective coating was produced on the surface of C/SiC coated carbon/carbon compo ites by a pack cementation technique. The phase composition and microstructure of the as-prepared coatings were characterized by XRD （X-ray diffraction）, SEM （scanning electron microscopy） and EDS （energy dispersive spectroscopy）. Oxidation behavior of the multiphase coated C/C composites was also investigated. It showed that the as-prepared coating characterized by excellent oxidation resistance and thermal shock re- sistance could effectively protect C/C composites from oxidation at 1773 K for 57 h in air and endure the thermal cycle between 1773 K and room temperature for 12 times, whereas the corresponding weight loss is only 1.47%. The excellent oxidation protective ability of the SiC-Si-ZrSiO4 coating could be attributed to the C/SiC gradient inner layer and the multiphase microstructure of the coating.

关键词： Carbon/carbon composites Oxidation Coating

Investigating Ion Transport through Artificial Transmembrane Channels Containing Introverted Groups

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Chinese Journal of Chemistry 2022年第11期40卷 1293-1297页

作者： Ya-Wei li Yong-Hong Fu Jun-li hou Department of Chemistry Fudan University220 Handan RoadShanghai 200433China

The investigation on the relationship between structure and transport activity of artificial transmembrane channels has still re-mained a challenge because of lacking strategy to precisely arrange the functional group in the channel ***,we report a general strategy to monitor ion transport through the artificial channels by using unimolecular tubular molecules containing intro-verted *** found that the ion transport rate decreased with elongation of the introverted sidechains and the channel with propyl group as the introverted sidechain exhibited the longest opening duration ***,we have revealed that,comparing to the ion transport rate,the opening duration is a more important factor for determining the transport activity of the artificial channels.

关键词： Supramolecular chemistry Self-assembly Nanostructures Artificial transmembrane channels Pillararene

Optical enhanced interferometry with two-mode squeezed twin-Fock states and parity detection

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Chinese Physics B 2020年第3期29卷 202-208页

作者： li-li hou Shuai Wang Xue-Fen Xu School of Mathematics and Physics Jiangsu University of TechnologyChangzhou 213001China Department of Fundamental Courses Wuxi Institute of TechnologyWuxi 214121China

We theoretically investigate the quantum enhanced metrology using two-mode squeezed twin-Fock states and parity detection. Our results indicate that, for a given initial squeezing parameter, compared with the two-mode squeezed vacuum state, both phase sensitivity and resolution can be enhanced when the two-mode squeezed twin-Fock state is considered as an input state of a Mach–Zehnder interferometer. Within a constraint on the total photon number, although the two-mode squeezed vacuum state gives the better phase sensitivity when the phase shift φ to be estimated approaches to zero, the phase sensitivity offered by these non-Gaussian entangled Gaussian states is relatively stable with respect to the phase shift itself. When the phase shift slightly deviates from φ= 0, the phase sensitivity can be still enhanced by the two-mode squeezed twin-Fock state over a broad range of the total mean photon number where the phase uncertainty is still below the quantum standard noise limit. Finally, we numerically prove that the quantum Cramer–Rao bound can be approached with the parity detection.

关键词： quantum optics phase sensitivity quantum metrology

Microstructure and Mechanical Properties of TWIP Steel Joints

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Journal of Iron and Steel Research International 2014年第8期21卷 749-756页

作者： li-li MA Ying-hui WEI li-feng hou Bin YAN College of Materials and Engineering Taiyuan University of Technology

As a new type of high manganese steel, the twinning induced plasticity （TWIP） steels have attracted a growing interest in the automotive industry due to their good performance. Thin plates of TWIP steel were welded by laser beam welding （LBW） and gas tungsten arc welding （GTAW）. The microstructure result shows that GTAW joint has obvious heat-affected zone （HAZ）, while the HAZ of LBW joint is almost invisible. The X-ray diffraction result shows that the phase compositions of both joints are austenitic and no phase transition occurs. Energy disper- sive spectrometry result shows that there is violent evaporation of Mn element in LBW joint, while the proportion of Mn element in GTAW joint is almost unchanged. Tensile tests and micro-hardness measurements were performed to take into account the mechanical properties of joints manufactured by the two different processes. The micro-hard- ness profiles of both joints present a typical saddle distribution, and the hardness of GTAW seam is lower than that of LBW seam. The failure positions of LBW joints are all located in base metal while the GTAW joints are all at the weld toe due to the softening of HAZ. By means of scanning electron microscopy, a typical ductile fracture is observed in LBW joint, while a brittle fracture with quasi-cleavage fracture characteristic is observed in GTAW joint.

关键词： TWIP steels high manganese steels LBW GTAW

Pillar[n]arenes: Chemistry and Their Material Applications

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Chinese Journal of Chemistry 2020年第2期38卷 215-217页

作者： Harekrushna Behera Lu Yang Jun-li hou Department of Chemistry Fudan University220 Handan RoadShanghai 200433China Department of Chemistry Western UniversityLondonOntarioCanada

Background Pillar[n]arene(PA[n])contains a symmetrical structures,where para-bridge connection between the units looks like a column-like or pillar shape and polygonal structure from side and top views,*** attached gr... 详细信息

关键词： attached directions opposite