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交变电场作用下黏性射流的稳定性分析

Acta Mechanica Sinica 2024年第2期40卷 15-27页

作者：谢络崔孝贾伯琦李强胡海豹 School of Marine Science and Technology Northwestern Polytechnical UniversityXi’an710072China Chongqing Science and Technology Innovation Center Northwestern Polytechnical UniversityChongqing400799China institute of Magnetic Levitation and Electromagnetic Propulsion Beijing100074China School of Mechanical and Electronic Control engineering Beijing Jiaotong UniversityBeijing100044China Department of Mechanical engineering Faculty of EngineeringNational University of SingaporeSingapore117575Singapore

液体射流在静电或交变电场作用下的失稳和破裂问题在许多工业应用中都有涉及.与静电场作用下射流稳定性研究相比,交变电场下射流的稳定性分析研究要少得多.因此,本文采用电场力和黏性力共同修正压强的黏势流模型来描述交变电场作用下漏... 详细信息

液体射流在静电或交变电场作用下的失稳和破裂问题在许多工业应用中都有涉及.与静电场作用下射流稳定性研究相比,交变电场下射流的稳定性分析研究要少得多.因此,本文采用电场力和黏性力共同修正压强的黏势流模型来描述交变电场作用下漏电介质液体射流的线性不稳定性,主要研究了交变电场、流体电学性质等参数的影响.交变电场作用下射流的毛细不稳定与静电场作用下射流不稳定特性是相似的.在足够强交变电场作用下,参数不稳定主导表面扰动的发展,从而进入共振电雾化模式.参数不稳定会被黏性耗散抑制,甚至随着频率的增加会完全消失.同时,导电电荷(主要取决于流体导电性)的作用与表面电荷是相反的,因此当电荷弛豫时间接近交变电场周期时,参数不稳定会受到强烈的抑制作用.此外,当气动作用足够强时,参数不稳定会被覆盖.

关键词：液体射流静电场射流稳定性交变电场电场力黏性力电介质表面电荷

光学微球纳米成像技术——进展与挑战（英文）

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engineering 2024年第5期 102-123页

作者：吴光兴洪明辉 Department of Electrical and Computer engineering National University of Singapore Pen-Tung Sah institute of Micro-Nano Science and Technology Xiamen University Innovation Laboratory for Sciences and Technologies of Energy Materials of Fujian Province (IKKEM)

The optical diffraction effect imposes a radical obstacle preventing conventional optical microscopes from achieving an imaging resolution beyond the Abbe diffraction limit and thereby restricting their usage in a multitude of nanoscale *** the past decade,the optical microsphere nanoimaging technique has been demonstrated to be a cost-effective solution for overcoming the diffraction limit and has achieved an imaging resolution of up to about ■in a real-time and label-free manner,making it highly competitive among numerous super-resolution imaging *** this review,we summarize the underlying nano-imaging mechanisms of the microsphere nanoscope and key advancements aimed at imaging performance enhancement:first,to change the working environment or modify the peripheral hardware of a single microsphere nanoscope at the system level;second,to compose the microsphere compound lens;and third,to engineer the geometry or ingredients of *** also analyze challenges yet to be overcome in optical microsphere nano-imaging,followed by an outlook of this technique.

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浮置板轨道周期结构弹性波传播特性及异常多普勒效应

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Journal of Central South University 2024年第5期31卷 1711-1722页

作者：张鑫浩赵才友惠庆敏耿明婧乐明静易强吕涛王平 School of Civil engineering Southwest Jiaotong UniversityChengdu 610031China Key Laboratory of High-speed Railway engineering Southwest Jiaotong UniversityChengdu 610031China Railway engineering Research institute China Academy of Railway Sciences Corporation LimitedBeijing 100081China SWJTU-Leeds Joint School Southwest Jiaotong UniversityChengdu 611756China

浮置板轨道因其良好的减振性能被广泛应用于城市轨道交通中。为研究浮置板结构的弹性波传播模式,本文基于广义平面波展开法,对其特征方程进行程序求解,得到了无限周期结构的复频散曲线。发现在0至300 Hz范围内存在八个带隙,并提出了相... 详细信息

浮置板轨道因其良好的减振性能被广泛应用于城市轨道交通中。为研究浮置板结构的弹性波传播模式,本文基于广义平面波展开法,对其特征方程进行程序求解,得到了无限周期结构的复频散曲线。发现在0至300 Hz范围内存在八个带隙,并提出了相应的理论分析。力锤激励试验也验证了带隙对弹性波的阻碍作用。根据波模式特性,发现双周期轨道结构的带隙形成机制与单周期轨道结构不同,即在双周期情况下,局部布拉格散射或局部共振无法阻止耦合弹性波的传播。频率-波数域的计算结果表明,异常多普勒效应发生在带隙范围,而常规多普勒效应发生在通带范围。

关键词：浮置板轨道带隙弹性波多普勒效应力锤激励试验

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De Novo Dissecting the Three‑Dimensional Facial Morphology of 2379 Han Chinese Individuals

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Phenomics 2024年第1期4卷 1-12页

作者： Hui Qiao Jingze Tan Shaoqing Wen Menghan Zhang Shuhua Xu Li Jin State Key Laboratory of Genetic engineering Center for Evolutionary BiologyCollaborative Innovation Center for Genetics and DevelopmentSchool of Life SciencesFudan UniversityShanghai 200438China Ministry of Education Key Laboratory of Contemporary Anthropology Human Phenome InstituteZhangjiang Fudan International Innovation CenterFudan UniversityShanghai 201203China institute of Archaeological Science Fudan UniversityShanghai 200433China institute of Modern Languages and Linguistics Fudan UniversityShanghai 200433China Department of Liver Surgery and Transplantation Liver Cancer institute Zhongshan HospitalFudan UniversityShanghai 200032China

Phenotypic diversity,especially that of facial morphology,has not been fully investigated in the Han Chinese,which is the largest ethnic group in the *** this study,we systematically analyzed a total of 14,838 facial traits representing 15 categories with both a large-scale three-dimensional(3D)manual landmarking database and computer-aided facial segmented phenotyping in 2379 Han Chinese *** results illustrate that homogeneous and heterogeneous facial morphological traits exist among Han Chinese populations across the three geographical regions:Zhengzhou,Taizhou,and *** identifed 1560 shared features from extracted phenotypes,which characterized well the basic facial morphology of the Han *** particular,heterogeneous phenotypes showing population structures corresponded to geographical *** greatest facial variation among these geographical populations was the angle of glabella,left subalare,and right cheilion(p=3.4×10^(−161)).Interestingly,we found that Han Chinese populations could be classifed into northern Han,central Han,and southern Han at the phenotypic level,and the facial morphological variation pattern of central Han Chinese was between the typical diferentiation of northern and southern Han *** result was highly consistent with the results revealed by the genetic *** fndings provide new insights into the analysis of multidimensional phenotypes as well as a valuable resource for further facial phenotype-genotype association studies in Han Chinese and East Asian populations.

关键词： Phenotypes Three-dimensional facial imaging Facial morphology Han Chinese

OsFK1 encodes C-14 sterol reductase,which is involved in sterol biosynthesis and affects premature aging of leaves in rice

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The Crop Journal 2024年第4期12卷 1010-1021页

作者： Ping Li Xia Zhang Wuzhong Yin Yang Shui Jie Zhang Nana Xu Dasong Bai Qingxiong Huang Yuanyuan Li Pan Qi Xing Li Qianlong Li Shihong Yang Guotao Yang Hong Chen Peng Qin Yungao Hu Youlin Peng Rice Research institute School of Life Science and EngineeringSouthwest University of Science and TechnologyMianyang 621010SichuanChina Hainan Yazhou Bay Seed Laboratory Sanya 572025HainanChina Rice Research institute State Key Laboratory of Crop Gene Exploration and Utilization in Southwest ChinaSichuan Agricultural UniversityChengdu 610061SichuanChina Yazhouwan National Laboratory Sanya 572704HainanChina

The enzyme C-14 sterol reductase is involved in biosynthesis of brassinosteroids(BR)and sterols,as well as plant ***1,a member of the sterol biosynthesis pathway located in the endoplasmic reticulum(ER),encodes C-14 sterol ***,there is little research on the function of C-14 sterol reductase in *** with the wild type,an osfk1 mutant showed dwarf phenotype and premature aging in the second leaf during the trefoil stage,and abnormal development of leaf veins during the tillering *** osfk1 mutant showed signs of aberrant PCD,as evidenced by TUNEL *** suggested that high ROS buildup caused DNA damage and ROS-mediated cell death in the *** osfk1 mutant also showed decreased chlorophyll content and aberrant chloroplast *** of the osfk1 mutant allele revealed a non-synonymous G to A mutation in the final intron,leading to early ***,we identified the OsFK1 allele,cloned it by Mutmap sequencing,and verified it by ***-MS/MS assays demonstrated that the osfk1 mutation caused lower phytosterol *** findings showed that the OsFK1 allele encoding C-14 sterol reductase is involved in phytosterol biosynthesis and mediates normal development of rice plants.

关键词： Leaf development ROS Phytosterol biosynthesis Rice

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Mobility of Major and Trace Elements during the Bauxitization Processes in Ngaoundal Area (Adamawa Cameroon): Implication on Mining Perspectives

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Open Journal of Geology 2024年第1期14卷 81-100页

作者： André Sini Harouna Boukari Ondoa Augustin Désiré Balla Djetenbe Beral Salomon Wangmené Awé Simon Djakba Basga Jean Pierre Nguetnkam Department of Mining engineering School of Geology and Mining Engineering University of Ngaoundere Ngaoundere Cameroon Department of Mining engineering and Environment School of Mining Industry and Geology University of Abdou-Moumouni Niamey Niger Department of Earth Sciences Faculty of Science University of Ngaoundere Ngaoundere Cameroon Department of Mining engineering Saint Jerome Polytechnic Saint Jerome Catholic University Institute of Douala Douala Cameroon institute of Agricultural Research for Development (IRAD) Garoua Cameroon

This study was focused to assess major and trace elements in bauxitic duricrusts from Ngaoundal and its surroundings in order to establish their mining interest. To this end, fieldworks, mineralogical and geochemical analyses were carried out. Four facies of duricrust were identified and characterized from the summit to the top of the slope of the Ngaoundal mountain: scoriaceous, pisolitic, nodular and massive. Mineralogical and geochemical analyses performed on 16 samples, revealed a significant concentration of Al2O3 mainly in the scoriaceous facies (over 45% in grade), moderate in Fe2O3 (averaging 23.69%) and SiO2 (averaging 21.7%). Trace elements were generally low, excluding Cr (421 ppm on average), Zr (327 ppm on average and V (213 ppm on average). In addition, the limited quantities of alkalis (Na2O, K2O) and alkaline earths metals (MgO, CaO) coupled with the very high values of Chemical Index of Alteration (CIA) and Mineralogical Index of Alteration (MIA), (more than 99%) attest to the intense weathering of the studied materials. Allitization and monosiallitization constituted the crystallochemical phenomena that have led to the development of bauxitic minerals. More than 90% of gibbsite in scoriaceous facies, 52.21% - 76.01% of kaolinite in pisolitic facies and more than 40% of hematite in nodular facies were quantified. The relationships between the constitutive components indicated their interdependency during the bauxitization phenomenon. The mineralogical and geochemical properties highlighted the mining interest of the studied duricrusts to be valorized.

关键词： Duricrust Bauxitization Phenomenon Mineralogical and Geochemical Characterization Major and Trace Elements Mining Potential

Enhanced Sampling Simulations on Transition-Metal-Catalyzed Organic Reactions:Zirconocene-Catalyzed Propylene Polymerization and Sharpless Epoxidation

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CCS Chemistry 2024年第4期6卷 964-975页

作者： Xu Han Tian-Yu Sun Yi Isaac Yang Jun Zhang Jing Qiu Zhaoping Xiong Nan Qiao Yun-Dong Wu Yi Qin Gao institute of Theoretical and Computational Chemistry College of Chemistry and Molecular EngineeringPeking UniversityBeijing 100871 Shenzhen Bay Laboratory Shenzhen 518132 Changping Laboratory Beijing 102200 Laboratory of Health Intelligence Huawei Cloud Computing Technologies Co.Ltd.Guizhou 550025

The bond breaking and forming in chemical reactions is a typical rare event,which is one of the difficult problems in molecular dynamics *** enhanced sampling methods have been developed to extend the time scale covered by molecular ***,the difficulties of obtaining appropriate collective variables from complicated reaction pathways and a controlled sampling over the desired phase space remain as ***,we use MetaITS,which combines metadynamics and integrated tempered sampling,to increase the sampling efficiency for chemical *** with collective variables obtained by harmonic linear discriminant analysis can efficiently decrease the main energy barrier of chemical ***,integrated tempered sampling can enhance the exploration of other degrees of *** this study,we applied the MetaITS method to two transition-metal-catalyzed organic reactions with complicated reaction *** simulated here a zirconocene-catalyzed propylene polymerization to investigate the regioselectivity and temperature *** also studied a Sharpless epoxidation reaction,for which both chiral products are observed through simulation.

关键词： molecular dynamics enhanced sampling metadynamics integrated tempering sampling propylene polymerization Sharpless epoxidation

Establishment of Constraint Relation of Robot Dynamics Equation Based on Kinematic Influence Coefficients Method

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Journal of Shanghai Jiaotong university(Science) 2024年第3期29卷 450-456页

作者：徐亚茹李克鸿商新娜金晓明刘荣张建成 Beijing engineering Research Center of Smart Mechanical Innovation Design Service Beijing Union UniversityBeijing 100027China College of Robotics Beijing Union UniversityBeijing 100020China Robotics institute Beihang UniversityBeijing 100191China

Due to the diversity of work requirements and environment,the number of degrees of freedom(DOFs)and the complexity of structure of industrial robots are constantly *** is difficult to establish the accurate dynamical model of industrial robots,which greatly hinders the realization of a stable,fast and accurate trajectory tracking ***,the general expression of the constraint relation in the explicit dynamic equation of the multi-DOF industrial robot is derived on the basis of solving the Jacobian matrix and Hessian matrix by using the kinematic influence coefficients ***,an explicit dynamic equation with general constraint relation expression is established based on the Udwadia-Kalaba *** problem of increasing the time of establishing constraint relationship when the multi-DOF industrial robots complete complex task constraints is *** the SCARA robot as the research object,the simulation results show that the proposed method can provide a new idea for industrial robot system modeling with complex constraints.

关键词： industrial robot constraint relationship kinematic influence coefficients method Jacobian matrix Hessian matrix

The role of Piezo1 and Piezo2 proteins in tissue engineering:A Comprehensive review

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Engineered Regeneration 2024年第2期5卷 170-185页

作者： Tejaswini Tadge Ashwini Pattewar Namdev More Srivalliputtur Sarath Babu Ravichandiran Velyutham Govinda Kapusetti National institute of Pharmaceutical Education and Research KolkataWest Bengal 700054India National institute of Pharmaceutical Education and Research AhmedabadGujarat 382355India

Almost every life form,from the tiniest bacterium to humans,is mechanosensitive,implying it can use mechani-cal stresses to trigger certain physiological responses in the form of electric *** largely relies on ion channels that respond to mechanical forces,such as the epithelial sodium channels/degenerins,tran-sient receptor potential channel,and the two-pore domain potassium ***1 and Piezo2 proteins were discovered to be the biggest non-selective mechanosensitive cation channels in the cell membrane.A substantial amount of research has previously been published on the Piezo channel’s function in touch sensation,balance,and cardiovascular ***,the mechanistic perspective must be refined to fully understand the role of Piezo proteins in tissue *** review centers on the latest insights into the structure of Piezo chan-nels,activation mechanisms,and its interactions with cytoskeletal components,by emphasizing the physiological activities of Piezo channels in different *** study also places focus on the possibilities of targeting this cation channel family as a tissue regeneration aid.

关键词： Piezo1 Piezo2 Mechanotransduction Tissue regeneration Mechanoreceptors