检索结果-南通市图书馆

Multi-scale modeling of liquid-metal cooling directional solidification and solidification behavior of nickel-based superalloy casting

引用

Journal of Materials Science & Technology 2021年第8期67卷 36-49页

作者： Xuewei Yan Qjngyan Xu Guoqiang Tian quanwei Liu Junxing Hou Baicheng Liu School of Aeronautical Engineering Zhengzhou University of AeronauticsZhengzhou 450046China School of Materials Science and Engineering Tsinghua UniversityKey Laboratory for Advanced Materials Processing TechnologyMinistry of EducationBeijing 100084China

Liquid-metal cooling(LMC)process can offer refinement of microstructure and reduce defects due to the increased cooling rate from enhanced heat extraction,and thus an understanding of solidification behavior in nickel-based superalloy casting during LMC process is essential for improving mechanical performance of single crystal(SC)*** this effort,an integrated heat transfer model coupling meso grain structure and micro dendrite is developed to predict the temperature distribution and microstructure evolution in LMC *** interpolation algorithm is used to deal with the macro-micro grids coupling *** algorithm of cells capture is also modified,and a deterministic cellular automaton(DCA)model is proposed to describe neighborhood cell *** addition,solute distribution is also considered to describe the dendrite *** measuring,EBSD,OM and SEM experiments are implemented to verify the proposed model,and the experiment results agree well with the simulation *** simulations are performed with a range of withdrawal rates,and the results indicate that 12 mm·min^(-1)is suitable for LMC process in this work,which can result in a fairly narrow and flat mushy zone and correspondingly exhibited fairly straight *** mushy zone length is about 4.8 mm in the steady state and the average deviation angle of grains is about 13.9°at the height 90 mm from the casting base under 12 mm·min^(-1)withdrawal *** competitive phenomenon of dendrites at different withdrawal rates is also observed,which has a great relevant to the temperature fluctuation.

关键词： Multi-scale model Numerical simulation Liquid-metal cooling Microstructure

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Simulation and optimization of a double THGEM detector

引用

Nuclear Science and Techniques 2013年第1期24卷 17-21页

作者： WANG Xiaohu WEI Tao LONG Jidong LI quanwei ZHANG Linwen Fundamental Science on Nuclear Waste and Environmental Security Laboratory Southwest University of Science and Technology Institute of Fluid Physics China Academy of Engineering Physics

A double thick GEM (THGEM) detector with thin THGEM foils and small holes was constructed. In order to optimize the operation parameters of the detector, a simulation study of the detector was carried out using ANSYS and Garfield program. Some important characteristics, including primary electron transparency, avalanche development and the secondary electron loss were calculated. Parameters, such as electric field and gas choice were optimized.

关键词：探测器优化模拟电子损失 ANSYS 操作参数创业板透明度

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Growth inhibition and apoptosis induction of tanshinone Ⅱ-A on human hepatocellular carcinoma cells

引用

World Journal of Gastroenterology 2004年第14期10卷 2024-2028页

作者： Shu-LanYuan Yu-quanwei Xiu-JieWang FeiXiao Sheng-FuLi JieZhang KeyLaboratoryofBiotherapyofHumanDiseases MinistryofEducationofChinaandCancerCenterWestChinaHospitalWestChinaMedicalSchoolSichuanUniversityChengdu610041SichuanProvinceChina

AIM: To evaluate the effects of tanshinone II-A on inducing growth inhibition and apoptosis of human hepatocellular carcinoma (HCC) cells,METHODS: The human hepatocellular carcinoma cell line SMMC-7721 was used for the study. The cells were treated with tanshinone II-A at different doses and different *** growth and proliferation were measured by MTT assay,cell count and colony-forming assay. Apoptosis induction was detected by microscopy, DNA ladder electrophoresis and flow ***: In MTT assay, the inhibitory effect became gradually stronger with the passage of time, 24, 48, 72and 96 h after treatment with tanshinone II-A, and the most significant effect was observed at 72 h. On the other hand, the increase of doses (0.125, 0.25, 0.5, 1.0 mg/L tanshinone II-A) resulted in enhanced inhibitory *** growth and proliferation of SMMC-7721 cells were obviously suppressed in a dose- and time-dependent manner. The results of cell count were similar to that of MTT assay. In colony-forming assay, the colony-forming rates were obviously inhibited by tanshinone II-A. In tanshinone II-A group, the morphology of cellular growth inhibition and characteristics of apoptosis such as chromatin condensation, crescent formation, margination and apoptotic body were observed under light and transmission electron microscopes. DNA ladder of cells was presented in electrophoresis. The apoptosis index (AI) was 16.9% (the control group was 4.6%) in flow cytometry. The cells were arrested in G0/G1 phase, and the expressions of apoptosis-related genes bd-2 and c-myc were down-regulated and fas, bax, p53 ***: Tanshinone II-A could inhibit the growth and proliferation of HCC cell effectively in vitro by apoptosis induction,which was associated with up-regulation of fas, p53, bax,expression and down-regulation of bcl-2 and c-myc.

关键词：生长抑制作用细胞调亡感应现象丹参酮Ⅱ-A 肝细胞癌肿瘤 HCC

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Dynamic targets searching assistance based on virtual camera priority

引用

Virtual Reality & Intelligent Hardware 2021年第6期3卷 484-500页

作者： Zixiang ZHAO quanwei ZHOU Xiaoguang HAN Lili WANG State Key Laboratory of Virtual Reality Technology and Systems School of Computer Science and EngineeringBeihang UniversityBeijing 100191China Beijing Advanced Innovation Center for Biomedical Engineering Beihang UniversityBeijing 100191China Department of Mathematics and Theories Peng Cheng LaboratoryShenzhen 518052China The Chinese University of Hong Kong Shenzhen 999077China Shenzhen Research Institute of Big Data Shenzhen 999077China

Background When a user walks freely in an unknown virtual scene and searches for multiple dynamic targets,the lack of a comprehensive understanding of the environment may have a negative impact on the execution of virtual reality *** studies can help users with auxiliary tools,such as top view maps or trails,and exploration guidance,for example,automatically generated paths according to the user location and important static spots in virtual ***,in some virtual reality applications,when the scene has complex occlusions,and the user cannot obtain any real-time position information of the dynamic target,the above assistance cannot help the user complete the task more *** We design a virtual camera priority-based assistance to help the user search dynamic targets *** of forcing users to go to destinations,we provide an optimized instant path to guide them to places where they are more likely to find dynamic targets when they ask for *** assume that a certain number of virtual cameras are fixed in virtual scenes to obtain extra depth maps,which capture the depth information of the scene and the locations of the dynamic *** method automatically analyzes the priority of these virtual cameras,chooses the destination,and generates an instant path to assist the user in finding the dynamic *** method is suitable for various virtual reality applications that do not require manual supervision or *** A user study is designed to evaluate the proposed *** results indicate that compared with three conventional navigation methods,such as the top-view method,our method can help users find dynamic targets more *** advantages include reducing the task completion time,reducing the number of resets,increasing the average distance between resets,and reducing user task *** We presented a method for improving dynamic target searching efficiency in virtual scenes by virtual cam

关键词： Searching assistance Virtual environment Path guidance Redirection

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Dynamic Expression Analysis and Introgressive Gene Identification of Fiber Length Using Chromosome Segment Substitution Lines from ***×***

引用

Phyton-International Journal of Experimental Botany 2021年第1期90卷 129-144页

作者： Pengtao Li quanwei Lu Xianghui Xiao Rui Yang Xixi Duan School of Biotechnology and Food Engineering Anyang Institute of TechnologyAnyang455000China Innovation and Practice Base for Postdoctors Anyang Institute of TechnologyAnyang455000China State Key Laboratory of Cotton Biology Key Laboratory of Biological and Genetic Breeding of CottonThe Ministry of AgricultureInstitute of Cotton ResearchChinese Academy of Agricultural SciencesAnyang455000China

Fiber length is a critical trait that principally determines cotton spinning quality,while Upland cotton as the most widely cultivated Gossypium species around the world subjects to the relatively ordinary fiber *** segment substitution lines(CSSLs)have been introduced in cotton breeding to take full advantages of superior fiber quality and high yield from Sea Island and Upland cotton,respectively,which serve as ideal materials for elucidating the genetic mechanism of complex quantitative ***,three CSSLs derived from CCRI45(***)×Hai1(***),two superior(MBI7561 and MBI7747)and one(MBI7285)with ordinary fiber-quality,were subjected to transcriptome sequencing during fiber elongation together with their recurrent parent CCRI45,and 471.425 million clean reads were obtained with 91.47%average Q30 and 45.23%mean GC *** total,5,673 differentially expressed genes(DEGs)were identified from multi-sample comparisons,which were mainly involved in the oxidation-reduction process,protein phosphorylation,regulation of transcription,DNA template,and carbohydrate metabolic *** temporal expression patterns were monitored on the DEGs of different lines,of which the significantly enriched profile revealed higher similarities between two superior CSSLs or the ordinary CSSL and CCRI45 with respect to fiber *** on the intersection between the predicted introgressive genes from RNAseq data and the published gene information from the *** genome,1,535 introgressive genes were identified in three *** analysis of the three common introgressive sections in superior CSSLs revealed eight candidate genes that were identified to be involved in fiber development,namely,O-fucosyltransferase family protein(GB_A02G0240),glutamine synthetase 2(GB_A02G0272),Ankyrin repeat family protein(GB_A02G0264),beta-6 tubulin(GB_D03G1742),WRKY DNA-binding protein 2(GB_D03G1655),quinolinate synthase(GB_D07G0623),nuclear factor

关键词： Gossypium hirsutum Gossypium barbadense chromosome segment substitution lines RNA-seq fiber length

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Multi-stage Virtual Over-sample Digital Hystersis Control

引用

中国电机工程学报 2012年第36期32卷 I0001-I0022,21页

作者： HU Yihua DENG Yan LIU quanwei TAO Yong Zhejiang University

并网电流控制是分布式发电系统中的技术难点。在分析传统滞环控制策略的基础上，针对不对称多电平拓扑研究了一种分段式虚拟过采样并网滞环控制策略。通过将母线电压按正弦波形分段的方法，可以有效分配开关管开关频率，降低输出电流的... 详细信息

并网电流控制是分布式发电系统中的技术难点。在分析传统滞环控制策略的基础上，针对不对称多电平拓扑研究了一种分段式虚拟过采样并网滞环控制策略。通过将母线电压按正弦波形分段的方法，可以有效分配开关管开关频率，降低输出电流的谐波含量。在真实采样点之间插入虚拟采样点的虚拟过采样方法，解决了滞环控制中环宽失效问题。利用仿真软件对多种滞环控制策略进行对比分析，搭建实验平台对提出的算法进行实验验证。仿真与实验结果都验证了所提控制算法的正确性。

关键词：滞环控制采样数滞环电流控制分布式发电系统虚拟多级无差拍控制单周期控制

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Performance of no-till corn precision planter equipped with row cleaners

引用

International Journal of Agricultural and Biological Engineering 2015年第5期8卷 15-25页

作者： Yang Li Zhang Rui Gao Nana Cui Tao Liu quanwei Zhang Dongxing College of Engineering China Agricultural UniversityBeijing 100083China

In the continuous annual wheat-corn cropping area of North China Plain,no-till planting that promotes soil conservation and crop yield while reducing operation cost has been gradually accepted by local ***,previous wheat residue is the main limiting factor affecting the performance of existing planters in placing seeds at uniform spacing and optimum depth in residue covered *** order to solve this problem,a kind of ground-wheel-driven row cleaner was designed,developed and mounted on row units of a four-row pneumatic precision *** planter has two adjacent row units equipped with the newly designed row cleaners and the other two adjacent row units equipped with the commonly used inactive row *** was used for planting at three forward speeds(4 km/h,6 km/h and 8 km/h)into half residue(HR)and whole residue(WR)*** amount of residue removal,seeding depth,emergence rate and indices of uniformity in seed spacing(missing-seeding index,quality of feeding index and precision index)were *** newly designed row cleaner performed better with regard to residue removal,with the average percentage of residue cleared as 63.0%compared to 40.3%for the inactive row *** the HR and WR plots,percentage of residue cleared of the newly designed row cleaner reached 57.1%and 68.9%respectively,suggesting that the newly designed row cleaner can work more effectively at high residue *** contrast,with the percentage of residue cleared of the inactive row cleaner as 43.1%and 37.5%in HR and WR plots,suggesting that the inactive row cleaner just can work effectively under low residue *** of missing-seeding index,QFI,precision index,coefficient of variation of depth and percent emergence for the newly designed row cleaner under whole residue level are comparable to those for the inactive row cleaner under half residue *** result indicates that the effect of using the newly designed row cleaner is equal to that of reducin

关键词： row cleaner corn production no-till planter wheat residue management annual double cropping system

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Correlation study between the square-coneenergy-absorbing structure and the frontal collisionbehaviour of leading vehicles

引用

Transportation Safety and Environment 2023年第3期5卷 60-77页

作者： Ping Xu Ying Gao Chong Huang Chengxing Yang Shuguang Yao quanwei Che Key Laboratory of Traffic Safety on Track of Ministry of Education Centr al South UniversityChangsha 410075HunanChina CRRC Qingdao Sifang Co. LtdQingdao 266111ShandongChina

In order to study the influence of square-cone energy-absorbing structures on the mechanical behaviour of the ollision performance of the leading vehicle,a parameterization method for rapidly changing the performance of energy-absorbing structures was ***,a finite element simulation model of the collision of the leading vehicle with a square-cone energy-absorbing structure was ***,the platform force,the slope of the platform force and the initial peak force of the force-displacement curve derived from the energy-absorbing structure were studied for the collision performance of the leading ***,the correlation model of the square-cone energy-absorbing structure and the mechanical behaviour of the collision performance of the leading vehicle was established by the response surface *** results showed that the increase of the platform force of the energy-absorbing structure can effectively buffer the longitudinal impact of the train and reduce the nodding attitude of the *** increase of the platform force slope can not only effectively buffer the longitudinal impact and vertical nodding of the train,but also reduce the lateral swing of the *** increase in the initial peak force to a certain extent may lead to a change in the deformation mode,thereby reducing the energy-absorption *** correlation model can guide the design of the square-cone energy-absorbing structure and predict the deformation attitude of the leading vehicle.

关键词： square-cone energy-absorbing structure parametric method correlation model collision performance rail vehicle

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Effects of Three Major Immunization Interventions on Measles Control—China,1952–2021

引用

China CDC weekly 2023年第17期5卷 385-390页

作者： quanwei Song Chao Ma Lixin Hao Fuzhen Wang Zhijie An Zundong Yin Huaqing Wang National Immunization Program Chinese Center for Disease Control and PreventionBeijingChina

Measles,an acute respiratory infectious disease caused by the measles virus,was responsible for millions of deaths annually before the introduction of the measles vaccine(MV)(1).Widespread availability of measles vaccines and the initiation of the Expanded Program on Immunization,approved at the 27th World health Assembly in 1974(2),have significantly improved global measles *** China,measles has been a statutorily notifiable disease since the establishment of the National Notifiable Diseases Reporting System(NNDRS)in 1950(3).

关键词： annually Measles Major

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

The Anti-Penetration Performance and Mechanism of Metal Materials:A Review

引用

Engineering 2024年第9期40卷 131-157页

作者： Jialin Chen Shutao Li Shang Ma Yeqing Chen Yin Liu quanwei Tian Xiting Zhong Jiaxing Song State Key Laboratory of Target Vulnerability Assessment Beijing 100036China Institute of Defense Engineering Academy of Military SciencePLABeijing 100036China Xi’an Rare Metal Materials Institute Co. Ltd.Xi’an 710016China

This article reviews the anti-penetration principles and strengthening mechanisms of metal materials,ranging from macroscopic failure modes to microscopic structural characteristics,and further summarizes the micro-macro correlation in the anti-penetration ***,it outlines the constitutive models and numerical simulation studies utilized in the field of impact and *** the macro perspective,nine frequent penetration failure modes of metal materials are summarized,with a focus on the analysis of the cratering,compression shear,penetration,and plugging stages of the penetration *** reasons for the formation of adiabatic shear bands(ASBs)in metal materials with different crystal structures are elaborated,and the formation mechanism of the equiaxed grains in the ASB is *** the strength and the toughness of metal materials are related to the materials’crystal structures and *** toughness is mainly influenced by the deformation mechanism,while the strength is explained by the strengthening ***,the mechanical properties of metal materials depend on their microstructures,which are subject to the manufacturing process and material *** numerical simulation,the advantages and disadvantages of different constitutive models and simulation methods are summarized based on the application characteristics of metal materials in high-speed penetration *** summary,this article provides a systematic overview of the macroscopic and microscopic characteristics of metal materials,along with their mechanisms and correlation during the anti-penetration and impact-resistance processes,thereby making an important contribution to the scientific understanding of anti-penetration performance and its optimization in metal materials.

关键词： Metal materials Failure model Adiabatic shear band Strengthening mechanisms Numerical simulation

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

欢迎您,

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

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

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

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

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：