检索结果-内蒙古大学图书馆

Design of Lattice Structures Using Local Relative Density Mapping Method

Chinese Journal of Mechanical Engineering 2018年第5期31卷 110-118页

作者： Guo-Hua Song Shi-Kai Jing Fang-Lei Zhao Ye-Dong Wang Hao Xing Long-Fei Qie Beijing Xinghang Mechanical-electrical Equipment Co.Ltd. Beijing 100074 China School of Mechanical Engineering Beijing Institute of Technology Beijing 100081 China

In order to solve the problem of substantial computational resources of lattice structure during optimization, a local relative density mapping(LRDM) method is proposed. The proposed method uses solid isotropic microstructures with penalization to optimize a model at the macroscopic scale. The local relative density information is obtained from the topology optimization result. The contour lines of an optimized model are extracted using a density contour approach, and the triangular mesh is generated using a mesh generator. A local mapping relationship between the elements’ relative density and the struts’ relative cross?sectional area is established to automatically determine the diameter of each individual strut in the lattice structures. The proposed LRDM method can be applied to local finite element meshes and local density elements, but it is also suitable for global ones. In addition, some cases are con?sidered in order to test the e ectiveness of the LRDM method. The results show that the solution time of the LRDM is lower than the RDM method by approximately 50%. The proposed method provides instructions for the design of more complex lattice structures.

关键词： Lattice structures Local relative density mapping Topology optimization Additive manufacturing

来源：评论

学校读者我要写书评

暂无评论

research and Realization of a Master-Slave Robotic System for Retinal Vascular Bypass Surgery

引用

Chinese Journal of Mechanical Engineering 2018年第4期31卷 48-57页

作者： Chang-Yan He Long Huang Yang Yang Qing-Feng Liang Yong-Kang Li School of Mechanical Engineering and Automation Beihang University Beijing Institute of Ophthalmology Beijing Tongren Eye CenterBeijing Tongren HospitalCapital Medical UniversityBeijing Key Laboratory of Ophthalmology and Visual Sciences

Retinal surgery continues to be one of the most technical demanding surgeries for its high manipulation accuracy requirement, small and constrained workspace, and delicate retinal tissue. Robotic systems have the potential to enhance and expand the capabilities of surgeons during retinal surgery. Thus, focusing on retinal vessel bypass surgery, a master-slave robot system is developed in this paper. This robotic system is designed based on characteristics of retinal vascular bypass surgery and analysis of the surgical workspace in eyeball. A novel end-effector of two degrees of freedom is designed and a novel remote center of motion mechanism is adopted in the robot *** kinematics and the mapping relationship are then established, the gravity compensation control strategy and the hand tremor elimination algorithm are applied to achieve the high motion accuracy. The experiments on an artificial eyeball and an in vitro porcine eye are conducted, verifying the feasibility of this system.

关键词： Retinal robotic system Mechanism design Kinematics Gravity compensation

来源：评论

学校读者我要写书评

暂无评论

Sorption of vanadium (V) on three typical agricultural soil of the Loess Plateau, china

引用

ENVIRONMENTAL POLLUTANTS AND BIOAVAILABILITY 2019年第1期31卷 120-130页

作者： Jiang, Yanji Yin, Xianqiang Luo, Xiuhua Yu, Lin Sun, Huimin Wang, Nong Mathews, Shiny Northwest A&F Univ Coll Nat Resources & Environm Yangling Shaanxi Peoples R China Minist Agr Key Lab Plant Nutr & Agrienvironm Northwest China Yangling Shaanxi Peoples R China Suzhou Wetland Protect & Management Stn Suzhou Peoples R China Minist Agr Peoples Republ China Agroenvironm Protect Inst Tianjin Peoples R China North Dakota State Univ Soil Sci Dept Fargo ND USA

Selected three soil (yellow cinnamon soil, manual loessial soil and aeolian sandy soil) to study the kinetics and isotherms sorption of V(V), and further explore the differences in the adsorption mechanism caused by initial V (V) concentration, ionic strength (IS), pH and different reaction times. It was observed that V(V) adsorption onto the soil had three processes and completed rapid adsorption in 60, 100 and 120 min. The maximum adsorbing capacity of V(V) on yellow cinnamon soil, manual loessial soil and aeolian sandy soil reached stable in pH range from 4 to 8. The adsorption capacity decreased with the increase of IS. V(V) adsorption onto soil varied greatly with mineralogy and properties of soil, the surface area, soil organic carbon content and composition of particulate matter. This research enhanced the understanding of how soil properties affect vanadium (V) sorption onto agricultural *** investigate the reaction mechanism between vanadium (V) and soil, and further explore the differences in the adsorption mechanism caused by initial V(V) concentration, ionic strength, pH and different reaction times. Selected three soil (yellow cinnamon soil, manual loessial soil and aeolian sandy soil) which are the typical agricultural soil from Shaanxi province to study the kinetics and isotherms sorption of V(V). SEM study is used to probe the morphological features of the soil in the presence of vanadium and to investigate the change of surface functional groups on the three soils after adsorption by the FTIR spectra. It was observed that V(.) adsorption onto the soil had three processes and completed rapid adsorption in 60 min, 100 min and 120 min. The maximum adsorption concentration of V(V) derived from experimental data for the yellow cinnamon soil, manual loessial soil and aeolian sandy soil were 1124.6mg kg, 854.4mg kg and 748.6mg kg, respectively. The maximumadsorbing capacity of V(V) on yellow cinnamon soil, manual loessial soil and aeolian sandy soil re

关键词： Adsorption vanadium soil pH IS

来源：评论

学校读者我要写书评

暂无评论

Stereo PIV measurement of vortices in a model pump intake 29

Stereo PIV measurement of vortices in a model pump intake

引用

29th IAHR Symposium on Hydraulic Machinery and Systems (IAHR)

作者： Guo, Miao Tang, Xuelin Li, Xiaoqin Wang, Fujun China Agr Univ Coll Water Resources & Civil Engn Beijing 100083 Peoples R China China Agr Univ Beijing Engn Res Ctr Safety & Energy Saving Techn Beijing 100083 Peoples R China

In the present paper, in order to improve and understand of various vortices which form in pump intake, a stereo PIV (Particle Image Velocimetry) technique has been used to investigate the vortex flows in a model pump intake comprising a vertical intake pipe with a bell mouth in a horizontal hexahedral intake under conditions of consistent flow rate and different water level. Two different flow regimes are observed for two cases: a "critical water level (CWL)" for a critical flow rate (case 1);a "higher water level" for a consistent flow rate with previous one (case 2), and the velocity vector, streamline and vorticity distributions on selected measurement sections are analyzed systematically. Comparing the experimental results between case 1 and 2: the number and strength of the vortex decrease with the increase of the water level on selected measurement sections of the free surface, one sidewall and floor. Moreover, there is not any distinct vortex formed on the section of another side wall for two cases neither. The number of vortex on the section of the back wall for case 1 is more than that for case 2, but the strength and the scale for case 1 are lower than that for case 2 on the same section.

关键词： Vortex flow

来源：评论

学校读者我要写书评

暂无评论

Design and optimization of equivalent consumption minimization strategy for 4WD hybrid electric vehicles incorporating vehicle connectivity

引用

Science china(technological Sciences) 2018年第1期61卷 147-157页

作者： QIU LiHong QIAN LiJun ZOMORODI Hesam PISU Pierluigi Department of Vehicle Engineering Hefei University of Technology International Center for Automotive Research Clemson University

This paper presents an optimized equivalent consumption minimization strategy(ECMS) for four-wheel-drive(4 WD) hybrid electric vehicles(HEVs) incorporating vehicle connectivity. In order to be applicable to the 4 WD architecture, the ECMS is designed based on a rule-based strategy and used under the condition that a certain propulsion mode is activated. Assuming that a group of 4 WD HEVs are connected and position information can be shared with each other, we formulate a decentralized model predictive control(MPC) framework that compromises fuel efficiency, mobility, and inter-vehicle distance to optimize the velocity profile of each individual vehicle. Based on the optimized velocity profile, an optimization problem considering both fuel economy and battery state of charge(SOC) sustainability is formulated to optimize the equivalent factors(EFs) of the ECMS for HEVs over an appropriate time window. MATLAB User Datagram Protocol(UDP) is used in the codes run on multiple computers to simulate the wireless communication among vehicles, which share position information via UDP-based communication, and dSPACE is used as a software-in-the-loop platform for the simulation of the optimized ECMS. Simulation results validate the control effectiveness of the proposed method.

关键词： equivalent consumption minimization strategy(ECMS) hybrid electric vehicles(HEVs) model predictive control(MPC) connected vehicles signal phase and timing(SPAT) optimization

来源：评论

学校读者我要写书评

暂无评论

Deletion of Atg22 gene contributes to reduce programmed cell death induced by acetic acid stress in Saccharomyces cerevisiae

引用

BIOtechNOLOGY FOR BIOFUELS 2019年第1期12卷 298-298页

作者： Hu, Jingjin Dong, Yachen Wang, Wei Zhang, Wei Lou, Hanghang Chen, Qihe Zhejiang Univ Dept Food Sci & Nutr Key Lab Food Microbial Technol Zhejiang Prov Hangzhou 310058 Zhejiang Peoples R China Cleveland Clin Dept Cardiovasc & Metab Sci Lerner Res Inst Cleveland OH 44106 USA Zhejiang Acad Agr Sci Inst Qual & Stand Agr Prod Hangzhou 310021 Zhejiang Peoples R China

Backgroundprogrammed cell death (PCD) induced by acetic acid, the main by-product released during cellulosic hydrolysis, cast a cloud over lignocellulosic biofuel fermented by Saccharomyces cerevisiae and became a burning problem. Atg22p, an ignored integral membrane protein located in vacuole belongs to autophagy-related genes family;prior study recently reported that it is required for autophagic degradation and efflux of amino acids from vacuole to cytoplasm. It may alleviate the intracellular starvation of nutrition caused by Ac and increase cell tolerance. Therefore, we investigate the role of atg22 in cell death process induced by Ac in which attempt is made to discover new perspectives for better understanding of the mechanisms behind tolerance and more robust industrial strain *** this study, we compared cell growth, physiological changes in the absence and presence of Atg22p under Ac exposure conditions. It is observed that disruption and overexpression of Atg22p delays and enhances acetic acid-induced PCD, respectively. The deletion of Atg22p in S. cerevisiae maintains cell wall integrity, and protects cytomembrane integrity, fluidity and permeability upon Ac stress by changing cytomembrane phospholipids, sterols and fatty acids. More interestingly, atg22 deletion increases intracellular amino acids to aid yeast cells for tackling amino acid starvation and intracellular acidification. Further, atg22 deletion upregulates series of stress response genes expression such as heat shock protein family, cell wall integrity and *** findings show that Atg22p possessed the new function related to cell resistance to Ac. This may help us have a deeper understanding of PCD induced by Ac and provide a new strategy to improve Ac resistance in designing industrial yeast strains for bioethanol production during lignocellulosic biofuel fermentation.

关键词： Saccharomyces cerevisiae atg22 Acetic acid programmed cell death Amino acid transport Cell wall and cytomembrane

来源：评论

学校读者我要写书评

暂无评论

Duplicated major histocompatibility complex class II genes in the tongue sole (Cynoglossus semilaevis)

引用

INTERNATIONAL JOURNAL OF IMMUNOGENETICS 2018年第4期45卷 210-224页

作者： Li, C. Jiang, J. Zhang, Q. Wang, X. Ocean Univ China Coll Marine Life Sci Key Lab Marine Genet & Breeding Minist Educ Qingdao Peoples R China

The major histocompatibility complex (MHC) molecule plays an important role in the vertebrate immune system. However, we have a limited understanding of the MHC genomic structure in teleosts. Using gene cloning and family analysis, we isolate the MHC class II genes in the tongue sole (Cynoglossus semilaevis) and find that both class II A and class II B genes are duplicated (named Cyse-DAA and Cyse-DBA, Cyse-DAB and Cyse-DBB, respectively). The class II A genes consist of four exons with a highly conserved genomic structure, but each gene has unique and defining exon 2 and intron 2 sequences. The class II B genes have a conserved six-exon genomic structure, with intron 3 splitting the 2 encoding region into two exons. Each class II B gene has unique variations in exon 2 and intron 1 sequences. The two class II A genes have similar expression patterns among tissues, with high levels in spleen and gill. Both class II B genes have similar patterns, with high expression in spleen, gill and intestine. The alleles of MHC class II have wide distribution and reliable inheritance in the families analysed. This indicates that the duplicated MHC genes are all classical class II genes. The class II gene duplication with divergent exon and intron sequences, but similar expression patterns in tongue sole provides new insights into MHC evolution.

关键词： fish gene duplication major histocompatibility complex pleuronectiformes teleost

来源：评论

学校读者我要写书评

暂无评论

Connected vehicle-based red-light running prediction for adaptive signalized intersections

引用

JOURNAL OF INTELLIGENT TRANSPORTATION SYSTEMS 2018年第3期22卷 229-243页

作者： Li, Meng Chen, Xiqun (Michael) Lin, Xi Xu, Dingyuan Wang, Yinhai Tsinghua Univ Dept Civil Engn Beijing Peoples R China Zhejiang Univ Coll Civil Engn & Architecture 866 Yuhangtang RdB828 Anzhong Bldg Hangzhou 310058 Zhejiang Peoples R China Univ Washington Dept Civil & Environm Engn Seattle WA 98195 USA

This article proposes a connected vehicle (CV)-based dynamic all-red extension (DARE) framework for adaptive signalized intersections to avoid potential crashes caused by red-light running (RLR) behavior. The conceptual framework consists of three components: CVs, road-ide equipment (RSE), and traffic control devices. The RLR prediction of signalized intersections is a crucial component of DARE that avoids potential collisions caused by RLR behavior. This article formulates the RLR prediction as a binary classification problem based on continuous trajectories measured by radar sensors. In the CV environment, vehicle trajectories and real-time signal timing could be obtained via vehicle-to-infrastructure and vehicle-to-vehicle communications. Using continuous trajectories, individual speed, acceleration, and distance to the stop line at the red-light onset time are selected as classification attributes. Nonweighted and weighted least square support vector machines (LS-SVM) are adopted to solve the RLR prediction problem. Parameter tuning is conducted by the cross-validation in the discrete parameter space and the Bayesian inference in the continuous parameter space, respectively. As a comparison, the existing DARE approach at adaptive signalized intersections based on inductive loop detectors is discussed. In field experiments, vehicle trajectories collected by radar sensors were used to simulate the CV environment. Results showed merits of the proposed continuous trajectories-based DARE approach in terms of prediction rate, missing rate and false alarm rate, and thus a better RLR prediction improved the intersection safety.

关键词： connected vehicle (CV) dynamic all-red extension (DARE) intersection least squares support vector machines (LS-SVM) radar red-light-running (RLR)

来源：评论

学校读者我要写书评

暂无评论

Vertical holding capacity of torpedo anchors in underwater cohesive soils

引用

OCEAN ENGINEERING 2018年 161卷 291-307页

作者： Wang, Wenkai Wang, Xuefeng Yu, Guoliang Shanghai Jiao Tong Univ Sch Naval Architecture Ocean & Civil Engn SKLOE CISSE Shanghai 200240 Peoples R China China Waterbome Transport Res Inst Beijing 100088 Peoples R China

Torpedo anchors are regarded as one of the most efficient mooring solutions for taut mooring systems and can withstand vertical loads. The estimation of the undrained pullout capacity of the anchors is vital for the design of offshore floating facilities. There have been some achievements obtained for the calculation of the holding capacity of a torpedo anchor via field tests, conventional model tests under one gravity, centrifuge tests with a high value of gravity acceleration and numerical tests. However, a simple and reliable formula is still required to calculate the holding capacity of a torpedo anchor. In this study, 240 sets of laboratory tests were performed, and 11 differently shaped model anchors, vertically embedded in a soft sedimentary bed, were pulled out vertically from different types of cohesive soils and different embedment depths. The characteristics of the loading curves were analyzed, and the relationship between the pullout capacities and properties of the anchors and types of soils were investigated. Based on force analysis and the laboratory data, a formula was proposed for the calculation of the undrained monotonic holding capacity of a torpedo anchor, which mainly depends on the embedded depth of the anchor, net weight, geometry, and in situ soil properties. The calculated vertical holding capacities were consistent with the laboratory and field data obtained by the authors and other scientists.

关键词： Torpedo anchor Pullout force Vertical pullout capacity Cohesive soil Embedded depth

来源：评论

学校读者我要写书评

暂无评论

Structural basis for the acetylation of histone H3K9 and H3K27 mediated by the histone chaperone Vps75 in Pneumocystis carinii

引用

Signal Transduction and Targeted Therapy 2019年第1期4卷 550-561页

作者： Yiping Chen Yang Zhang Hui Ye Yanshu Dou Deren Lu Xiaolu Li Andrew H.Limper Junhong Han Dan Su State Key Laboratory of Biotherapy and Cancer Center West China HospitalSichuan UniversityChengduSichuanP.R.China Center of Infectious Diseases West China Hospital of Sichuan UniversityChengduSichuanP.R.China International Center for Translational Chinese Medicine Sichuan Academy of Chinese Medicine SciencesP.R.ChinaChengduSichuanP.R.China Thoracic Diseases Research Unit Mayo Clinic College of MedicineRochesterMNUSA

Rtt109 is a histone acetyltransferase(HAT)that is a potential therapeutic target in conditioned pathogenic fungi Pneumocystis carinii(***).The histone chaperone Vps75 can stimulate the Rtt109-dependent acetylation of several histone H3 lysines and preferentially acetylates H3K9 and H3K27 within canonical histone(H3–H4)2 ***75 shows two protein conformations assembled into dimeric and tetrameric forms,but the roles played by multimeric forms of Vps75 in Rtt109-mediated histone acetylation remain *** ***,we identified that Vps75(PcVps75)dimers regulate H3K9 and H3K27 acetylation by directly interacting with histone(H3–H4)2 tetramers,rather than by forming a Vps75-Rtt109 *** PcVps75 tetramers,the major histone-binding surface is buried within a walnut-like structure in the absence of a histone *** on crystal structures of dimeric and tetrameric forms of PcVps75,as well as HAT assay data,we confirmed that residues 192E,193D,194E,195E,and 196E and the disordered C-terminal tail(residues 224–250)of PcVps75 mediate interactions with histones and are important for the Rtt109 in ***(PcRtt109)-mediated acetylation of H3K9 and H3K27,both in vitro and in yeast ***,expressing PcRtt109 alone or in combination with PcVps75 variants that cannot effectively bind histones could not fully restore cellular growth in the presence of genotoxic agents that block DNA replication owing to the absence of H3K9 and H3K27 ***,these data indicate that the interaction between PcVps75 and histone(H3–H4)2 tetramers is a critical regulator of the Rtt109-mediated acetylation of H3K9 and H3K27.

关键词： residues Together acetylation

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：