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The cooperative migration dynamics of particles correlates to the nature of hexatic-isotropic phase transition in 2D systems of corner-rounded hexagons

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Fundamental Research 2024年第2期4卷 284-290页

作者： Zhanglin Hou Mingwei Liu yiwu zong Fangfu Ye Kun Zhao Wenzhou Institute University of Chinese Academy of SciencesWenzhouZhejiang 325001China Frontiers Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering(Ministry of Education) School of Chemical Engineering and TechnologyTianjin 300072China School of Physical Science University of Chinese Academy of SciencesBeijing 100049China Beijing National Laboratory for Condensed Matter Physics Institute of PhysicsChinese Academy of SciencesBeijing 100190China Oujiang Laboratory(Zhejiang Lab for Regenerative Medicine Vision and Brain Health)WenzhouZhejiang 325001China Sichuan Provincial People’s Hospital University of Electronic Science and Technology of ChinaChengduSichuan 610054China Institute of Fundamental and Frontier Sciences University of Electronic Science and Technology of ChinaChengduSichuan 610054China

In the two-dimensional(2D)melting transition of colloidal systems,the hexatic-isotropic(H-I)transition can be either first-order or ***,how particle dynamics differs at the single-particle level during these two different melting transitions remains to be *** this work,by Brownian dynamics(BD)simulations,we have systematically studied the dynamic behavior of corner-rounded hexagons during the H-I transition,for a range of corner-roundness𝜁=0.40 to 0.99 that covers the crossover from the continuous to first-order nature of H-I *** results show that hexagons with𝜁≤0.5 display a continuous H-I transition,whereas those with𝜁≥0.6 demonstrate a first-order H-I *** analysis shows different evolution pathways of the dominant cluster formed by migrating particles,which results in a droplet-like cluster structure for𝜁=0.40 hexagons and a tree-like cluster structure for𝜁=0.99 *** investigations on the hopping activities of particles suggest a cooperative origin of migrating *** work provides a new aspect to understand the dependence of the nature of H-I transition on the roundness of hexagons through particle dynamic behavior.

关键词： Melting transition Colloids Hexatic phase Cooperative migration Hexagons

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Phase behavior of rotationally asymmetric Brownian kites containing 90°internal angles

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Chinese Physics B 2021年第12期30卷 467-472页

作者： Huaqing Liu yiwu zong Zhanglin Hou Thomas G.Mason Kun Zhao Key Laboratory of Systems Bioengineering(Ministry of Education) School of Chemical Engineering and TechnologyTianjin UniversityTianjin 300072China Wenzhou Institute University of Chinese Academy of SciencesWenzhou 325001China Department of Physics and Astronomy University of California-Los AngelesLos AngelesCA 90095USA Department of Chemistry and Biochemistry University of California-Los AngelesLos AngelesCA 90095USA Physics Department Tianjin UniversityTianjin 300072China

Previous Monte Carlo simulations have shown that ordered tetratic phases can emerge in a dense two-dimensional Brownian system of rotationally asymmetric hard kites having 90°internal ***,there have been no experimental investigations yet to compare with these simulation ***,we have fabricated two types of micron-sized kites having internal angles of 72°-90°-108°-90°and 72°-99°-90°-99°,respectively,and we have experimentally studied their phase behavior in two-dimensional *** and in contrast to the Monte Carlo simulations,the experimental results show a phase sequence of isotropic fluid-hexagonal rotator crystal-square crystal as the area fractionφA increases for both types of *** observed square crystal displays not only a quasi-long-range translational order but also(quasi-)long-range 4-fold bond-and molecular-orientational order;these characteristics confirm that tetratic order can emerge even in dense Brownian systems of rotationally asymmetric particles.A model based on local polymorphic configurations(LPCs)is proposed to understand the origin of the square lattice order in these dense kite *** results in this study provide a new route to realize custom-designed self-assembly of colloids by controlling LPCs.

关键词： tetratic order colloidal kites two-dimentional system phase behavior

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Ray-optics model for optical force and torque on a spherical metal-coated Janus microparticle

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Photonics Research 2015年第5期3卷 265-274页

作者： Jing Liu Chao Zhang yiwu zong Honglian Guo Zhi-Yuan Li Key Laboratory of Optical Physics Institute of PhysicsChinese Academy of SciencesBeijing 100190China Key Laboratory of Soft Matter Physics Institute of PhysicsChinese Academy of SciencesBeijing 100190China

In this paper, we develop a theoretical method based on ray optics to calculate the optical force and torque on a metallo-dielectric Janus particle in an optical trap made from a tightly focused Gaussian beam. The Janus particle is a 2.8 μm diameter polystyrene sphere half-coated with gold thin film several nanometers in thickness. The calculation result shows that the focused beam will push the Janus particle away from the center of the trap,and the equilibrium position of the Janus particle, where the optical force and torque are both zero, is located in a circular orbit surrounding the laser beam axis. The theoretical results are in good agreement qualitatively and quantitatively with our experimental observation. As the ray-optics model is simple in principle, user friendly in formalism, and cost effective in terms of computation resources and time compared with other usual rigorous electromagnetics approaches, the developed theoretical method can become an invaluable tool for understanding and designing ways to control the mechanical motion of complicated microscopic particles in various optical tweezers.

关键词： Ray-optics model for optical force and torque on a spherical metal-coated Janus microparticle

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微生物细胞工厂合成甲基萘醌的研究进展

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科学通报 2022年第34期67卷 4055-4067页

作者：孙盼星李锋宗奕吾宋浩天津大学化工学院天津300072 天津大学合成生物学前沿科学中心系统生物工程教育部重点实验室天津300072 天津大学青岛海洋技术研究院青岛266237

甲基萘醌又称维生素K2,是人体必需的维生素之一,可以有效预防和治疗维生素K2缺乏性出血症、骨质疏松症、心血管疾病、慢性肾病等疾病,因此在食品和药品等领域有重要的应用价值.甲基萘醌的合成方法有两种:化学合成和生物合成.化学合成法... 详细信息

甲基萘醌又称维生素K2,是人体必需的维生素之一,可以有效预防和治疗维生素K2缺乏性出血症、骨质疏松症、心血管疾病、慢性肾病等疾病,因此在食品和药品等领域有重要的应用价值.甲基萘醌的合成方法有两种:化学合成和生物合成.化学合成法的产率低下、分离过程复杂等缺点限制了其规模化应用,而生物合成则利用可以天然合成甲基萘醌的微生物来生产甲基萘醌,具有操作简单、产物易分离等优点.本文首先总结了甲基萘醌生物合成过程及代谢途径的概况,包括底物摄取途径、莽草酸途径、萜烯骨架途径和甲基萘醌途径的研究进展.其次,针对这些途径的代谢工程改造,总结了大肠杆菌和枯草芽孢杆菌两种细胞工厂应用了哪些代谢工程策略,并介绍了限制甲基萘醌合成的关键途径和已构建的微生物细胞工厂合成甲基萘醌的产量情况.最后,比较了两种细胞工厂的工业应用价值,并对未来提高细胞工厂的产物合成能力进行了展望.

关键词：甲基萘醌代谢途径代谢策略微生物细胞工厂

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DUAL BASES FOR A NEW FAMILY OF GENERALIZED BALL BASES

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Journal of Computational Mathematics 2004年第1期22卷 79-88页

作者： Hong-yiwu DepartmentofMathematics HefeiUniversityofTechnologyHefei230009China

This paper presents the dual bases for a new family of generalized Ball curves with a position parameter K, which includes the Bezier curve, generalized Said-Ball curve and some intermediate curves. Using the dual bas... 详细信息

关键词： Bezier曲线 Marsden恒等式 Said-Ball曲线基底变换

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Singular formalism and admissible control of spacecraft with rotating flexible solar array

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Chinese Journal of Aeronautics 2014年第1期27卷 136-144页

作者： Lu Dongning Liu yiwu Science and Technology on Intelligent Space Control Laboratory Beijing Institute of Control Engineering Beijing Institute of Control Engineering

This paper is concerned with the attitude control of a three-axis-stabilized spacecraft which consists of a central rigid body and a flexible sun-tracking solar array driven by a solar array drive assembly. Based on the linearization of the dynamics of the spacecraft and the modal identities about the flexible and rigid coupling matrices,the spacecraft attitude dynamics is reduced to a formally singular system with periodically varying parameters,which is quite different from a spacecraft with fixed appendages. In the framework of the singular control theory,the regularity and impulse-freeness of the singular system is analyzed and then admissible attitude controllers are designed by Lyapunov’s method. To improve the robustness against system uncertainties,an H1optimal control is designed by optimizing the H1norm of the system transfer function *** numerical experiments are performed to verify the theoretical results.

关键词： Admissible control H1optimal control Modal identity Rotating flexible solar array Singular system

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Vapor-liquid equilibrium modeling for binary system of R152a/R1234ze(E)

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Chinese Journal of Chemical Engineering 2023年第10期62卷 124-131页

作者： Chuang Pan Yuande Dai yiwu Yi Yu Liao School of Advanced Manufacturing Nanchang UniversityNanchang 330031China

At present,the environment impact of refrigerants has been given *** binary mixture R152a/R1234ze(E)is an environmentally friendly refrigerant,which solves problems of poor cooling performance of the R1234ze(E)cycle and flammability of *** order to obtain its basic thermal and physical parameters,it is necessary to carry out vapor-liquid equilibrium(VLE)research,and the cubic equation of states(EOS)is often used in the calculation of the thermodynamic properties of *** this paper,the VLE predicted models for R152a/R1234ze(E)in the temperature range of 298.15-328.15 K were constructed using Soave-Redlich-Kwong(SRK),Peng-Robinson(PR)equations of state(EOS)combined with van der Waals(vd W),Huron-Vidal(HV)mixing rules,*** equilibrium pressures and vapor-phase mole fractions of the models were obtained by calculation,and all four models presented an extreme correlation with the experimental *** it can be concluded that the calculated results of the PR+HV model are closer to the experimental data than those of the other three models,with the average absolute deviation of 0.0027 for vapor-phase mole fraction(AAD(ycal))and the average absolute relative deviation of 0.243%for equilibrium pressure(AARD(pcal)),which provides a basis for accurately calculating the thermophysical properties of the mixture R152a/R1234ze(E).

关键词： Binary mixture Binary interaction coefficient PR+HV model SRK+HV model Vapor-liquid equilibrium

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Thermal Wind Imbalance along the Curved Streamline of the Secondary Circulation in Tropical Cyclones

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Journal of Meteorological Research 2023年第1期37卷 107-111页

作者： yiwu HUANG Yihong DUAN Xinyan LYU National Meteorological Centre China Meteorological AdministrationBeijing 100081 Chinese Academy of Meteorological Sciences China Meteorological AdministrationBeijing 100081

The thermal wind balance in tropical cyclone(TC)eyewalls has been controversial for *** study reveals the relationship between the acceleration and curvature on the TC secondary circulation streamline,providing a way to judge thermal wind balance or imbalance in TCs from a simple but clear *** to the relationship between the curvature and acceleration on the streamline,the vertical and radial components of the acceleration cannot be zero simultaneously on the streamline curve,implying that the thermal wind imbalance corresponds to the curvature of the *** the regular scales of TCs,we discuss the conditions of the thermal wind balance approximation and find that the conditions become more stringent with increasing *** the TC secondary circulation,as an indication of thermal wind imbalance,gradient wind imbalance can be found in the low-level eyewall since there is usually a large curvature when the inflow in the low-level eyewall turns into updrafts ***,gradient wind imbalance also appears at the top level of TC eyewalls because the stringent conditions are too easily broken there.

关键词： imbalance curvature secondary circulation tropical cyclone

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Classification of Multiple Scattering Sequences in the Glauber Amplitude for Nucleus-Nucleus Scattering

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Chinese journal of nuclear physics 1994年第1期16卷 17-20页

作者： Ruan, Wenying Chen, Fangzhen Duan, yiwu South China Univ of Technology Guangzhou China

A procedure is proposed to classify multiple scattering sequences in nucleus-nucleus scattering,with α-12C taken as an example.

关键词： Glauber multiple scattering Fourier transformation Matrix

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Effects of glucocorticoid and glucocorticoid receptors on stress-induced neurogenesis suppression

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Neural Regeneration Research 2010年第17期5卷 1330-1336页

作者： Xin Zhou Jiapei Dai Dan Liu Shangxun Li yiwu Zhou Department of Forensic Medicine Tongji Medical CollegeHuazhong University of Science and TechnologyWuhan 430030Hubei ProvinceChina Criminal Justice School Zhongnan University of Economics and LawWuhan 430073Hubei ProvinceChina Wuhan Institute for Neuroscience and Neuroengineering South-Central University for NationalitiesWuhan 430074Hubei ProvinceChina

Studies have shown that cerebral ischemia activates neurogenesis and that stress inhibits ***,the role of stress hormone levels on neurogenesis following cerebral ischemia remains poorly *** present study explored the possible regulatory mechanisms of adult neurogenesis under pathological conditions by examining changes and regulation of glucocorticoid receptors in adult rats subjected to transient unilateral middle cerebral artery suture *** levels gradually increased following middle cerebral artery occlusion,and the number of glucocorticoid receptor-positive cells *** number of5-bromodeoxyuridine-and nestin-positive cells significantly increased at 1 and 2 weeks after ischemia.A large number of doublecortin-positive cells migrated from the hippocampus to the *** 3 weeks post-surgery,the number of 5-bromodeoxyuridine-and nestin-positive cells significantly reduced in the subventricular *** corticosterone levels decreased vascular endothelial cell proliferation and neurogenesis,and the number of glucocorticoid receptor-positive cells *** the sham surgery group,vascular endothelial cell proliferation related to post-ischemic cerebral rehabilitation was not *** levels increased,but the number and distribution of glucocorticoid receptor-positive cells were not ***,normal neuregenesis and migration of neural stem cells existed in the adult rat brain in the sham surgery *** suggested that glucocorticoid receptors influenced neurogenesis and were negatively regulated by glucocorticoid levels following focal cerebral ischemia and reperfusion.

关键词： cerebral ischemia glucocorticoid receptor stress regulation neurogenesis neural regeneration

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