检索结果-南通市图书馆

A High-Accuracy Curve Boundary Recognition Method Based on the Lattice Boltzmann Method and Immersed Moving Boundary Method

引用

Computer Modeling in Engineering & Sciences 2024年第9期140卷 2533-2557页

作者： Jie-Di Weng yong-zheng jiang Long-Chao Chen Xu Zhang Guan-yong Zhang Hunan Provincial Key Laboratory of Health Maintenance for Mechanical Equipment Hunan University of Science and TechnologyXiangtan411201China School of Mechanical Engineering Hunan Chemical Vocational Technology CollegeZhuzhou412000China

Applying numerical simulation technology to investigate fluid-solid interaction involving complex curved bound-aries is vital in aircraft design,ocean,and construction ***,current methods such as Lattice Boltzmann(LBM)and the immersion boundary method based on solid ratio(IMB)have limitations in identifying custom curved ***,IBM based on velocity correction(IBM-VC)suffers from inaccuracies and numerical ***,this study introduces a high-accuracy curve boundary recognition method(IMB-CB),which identifies boundary nodes by moving the search box,and corrects the weighting function in LBM by calculating the solid ratio of the boundary nodes,achieving accurate recognition of custom curve *** addition,curve boundary image and dot methods are utilized to verify *** findings revealed that IMB-CB can accurately identify the boundary,showing an error of less than 1.8%with 500 ***,the flow in the custom curve boundary and aerodynamic characteristics of the NACA0012 airfoil are calculated and compared to *** showed that IMB-CB yields lower lift and drag coefficient errors than IBM-VC,with a 1.45%drag coefficient *** addition,the characteristic curve of IMB-CB is very stable,whereas that of IBM-VC is *** the moving boundary problem,LBM-IMB-CB with discrete element method(DEM)is capable of accurately simulating the physical phenomena of multi-moving particle flow in complex curved *** research proposes a new curve boundary recognition method,which can significantly promote the stability and accuracy of fluid-solid interaction simulations and thus has huge applications in engineering.

关键词： Fluid-solid interaction curve boundary recognition method Lattice Boltzmann method immersed moving boundary method

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

Method for Improving Transverse Wall Thickness Precision of Seamless Steel Tube Based on Tube Rotation

引用

Journal of Iron and Steel Research International 2015年第10期22卷 924-930页

作者： yong-zheng jiang Hua-ping TANG State Key Laboratory of High Performance Complex Manufacturing Central South University

The tube rotation method （TRM） refers to the rotational movement of steel tube about its axis as well as translation in rolling direction in stretch reducing rolling process. The influence of the TRM on transverse wall thickness precision of seamless steel tube was studied. Thickness distribution of the TRM was obtained by superimposing the thickened amount of single pass rolling. Results show that the TRM can effectively improve the evenness of thickness distribution. In order to analyze the influence mechanism of the TRM, the finite element method was adopted to simulate the thickness distribution in stretch reduction process. Results show that the TRM changes the roundtrip flow between two fix places of conventional stretch reducing and inhibits the directional accumulation of metal. In addition, the TRM has a correction effect on thickness cusp. All these advantages of the TRM help to improve the transverse wall thickness precision of seamless steel tube.

关键词： seamless tube stretch reducing transverse unevenness tube rotation method

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

Spatial Vibration and Its Numerical Analytical Method of Four-high Rolling Mills

引用

Journal of Iron and Steel Research International 2014年第9期21卷 837-843页

作者： yong-jiang zheng Guang-xian SHEN Yi-geng LI Ming LI Hong-min LIU School of Mechanical Engineering Yanshan University National Engineering Research Center for Equipment and Technology of Cold Strip Rolling Yanshan University

The rolls in contemporary four-high mills cannot be maintained parallel during the rolling process. There- fore, four-high rolling mill vibrations take place in six degree of freedom （DOF） leading to spatial behaviors invol- ving vertical, horizontal, axial, torsional, cross and swinging vibration modes resulting in complex relative motions between the rolls. Two numerical methods, modified Riccati-transfer matrix method （Riccati-TMM） and finite ele- ment method （FEM）, are presented to analyze a spatial vibration characteristic of two four-high rolling mills with different stability. The natural frequency and mode shape of four-high rolling mills are obtained, and the clearance has a great effect on natural frequency and mode shape. In addition, field testing experiment is also conducted to measure natural frequency by power spectrum analysis of rolling mill vibration. Experimental results basically agree with those calculated by Riccati-TMM and FEM, which means that the Riccati-TMM and the FEM can be used for analysis of spatial vibration of four-high rolling mill. Meanwhile, the spatial vibration shows more compound vibra- tion behaviors and the negative effect of horizontal, vertical, cross and swinging vibration modes are effectively con- trolled after redesign of rolling mill. These advantages have a great significance for the rolling mill to be operated with a much higher rolling speed and improved yield of products.

关键词： four-high roiling mill spatial vibration transfer matrix method FEM simulation

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

Bright InP quantum dots by Ga-doping for red emitters

引用

Nano Research 2024年第7期17卷 6721-6733页

作者： Kai-zheng Song Xiao-Hang He Zhe-yong Chen Ge Tang Jin-Zhao Huang Feng-Lei jiang College of Chemistry and Molecular Sciences Wuhan UniversityWuhan 430072China

Environment-friendly indium phosphide(InP)-based quantum dots(QDs)with efficient red-emitting properties are sufficiently needed to satisfy the requirement of burgeoning display and lighting ***,the syntheses of InP QDs using tris(trimethylsilyl)phosphine as the precursor are highly toxic and ***,we successfully introduced gallium(Ga)ions into tris(dimethylamino)phosphine-based red InP cores through thermally-promoted cation exchange,and the obtained Ga-doped InP cores exhibited significantly increased photoluminescence quantum yields(PLQY)of up to 26%.The existence of Ga was directly confirmed by energy-dispersive X-ray spectroscopy and X-ray photoelectron spectroscopy,and the functions of Ga were systematically *** subsequent coating of Ga-doped InP cores with ZnSeS and ZnS shells,the resulting Ga-InP/ZnSeS/ZnS QDs achieved a high PLQY of 62%with an emission maximum at 640 *** contrast,without Ga-doping,the PLQY only attained 36%using the same synthetic *** indicated an approximate 1.7-fold increase in *** enhancement of photoluminescence was related to the Ga^(3+),as it not only passivated surface defects of InP cores but also reduced core–shell interface *** Ga-InP/ZnSeS/ZnS QDs exhibited good stability towards heat treatment and ultraviolet(UV)***,the red light-emitting diode(LED)based on Ga-InP/ZnSeS/ZnS QDs performed well in a wide injected current range of 2 to 200 mA,with a maximum power efficiency of 0.68 lm/*** work showcases Ga-doping through cation exchange as a promising strategy for enhancing the efficiency of InP-based red emitters.

关键词： indium phosphide gallium doping optical properties light emitting diode

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

Refining the Factors Affecting N_(2)O Emissions from Upland Soils with and without Nitrogen Fertilizer Application at a Global Scale

引用

Advances in Atmospheric Sciences 2024年第9期41卷 1804-1820页

作者： Wenqian jiang Siqi LI yong LI Meihui WANG Bo WANG Ji LIU Jianlin SHEN Xunhua zheng State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China Key Laboratory for Agro-ecological Processes in Subtropical Regions Institute of Subtropical AgricultureChinese Academy of SciencesChangsha 410125China Changsha Research Station for Agricultural&Environmental Monitoring Chinese Academy of SciencesChangsha 410125China University of Chinese Academy of Sciences Beijing 100049China State Environmental Protection Key Laboratory of Formation and Prevention of the Urban Air Pollution Complex Shanghai Academy of Environment SciencesShanghai 200233China Institute of Carbon Neutrality Qilu ZhongkeJinan 251699China Hubei Province Key Laboratory for Geographical Process Analysis and Simulation Central China Normal UniversityWuhan 430079China Department of Ecohydrology Leibniz Institute of Freshwater Ecology and Inland FisheriesBerlin 12587Germany Key laboratory of Environment Change and Resources Use in Beibu Gulf Ministry of EducationNanning Normal UniversityNanning 530001China Golden Mantis school of Architecture Soochow UniversitySuzhou 215123China

Nitrous oxide(N_(2)O)is a long-lived greenhouse gas that mainly originates from agricultural *** and more studies have explored the sources,influencing factors and effective mitigation measures of N_(2)O in recent ***,the hierarchy of factors influencing N_(2)O emissions from agricultural soils at the global scale remains *** this study,we carry out correlation and structural equation modeling analysis on a global N_(2)O emission dataset to explore the hierarchy of influencing factors affecting N_(2)O emissions from the nitrogen(N)and non-N fertilized upland farming systems,in terms of climatic factors,soil properties,and agricultural *** results show that the average N_(2)O emission intensity in the N fertilized soils(17.83 g N ha^(-1)d^(-1))was significantly greater than that in the non-N fertilized soils(5.34 g N ha^(−1) d^(−1))(p<0.001).Climate factors and agricultural practices are the most important influencing factors on N_(2)O emission in non-N and N fertilized upland soils,*** different climatic zones,without fertilizer,the primary influence factors on soil N_(2)O emissions are soil physical properties in subtropical monsoon zone,whereas climatic factors are key in the temperate *** fertilizer,the primary influence factors for subtropical monsoon and temperate continental zones are soil physical properties,while agricultural measures are the main factors in the temperate monsoon *** enhanced agricultural practices,such as reduced N fertilizer rate combined with the addition of nitrification and urease inhibitors can potentially mitigate N_(2)O emissions by more than 60%in upland farming systems.

关键词： N_(2)O emissions influencing factors nitrogen cycling upland farming systems

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

Experimental and numerical simulation study on forced ventilation and dust removal of coal mine heading surface

引用

International Journal of Coal Science & Technology 2024年第1期11卷 204-220页

作者： Haotian zheng Bingyou jiang Haoyu Wang Yuannan zheng Key Laboratory of Industrial Dust Prevention and Control&Occupational Health and Safety Ministry of EducationAnhui University of Science and TechnologyHuainan232001China Joint National-Local Engineering Research Centre for Safe and Precise Coal Mining Anhui University of Science and TechnologyHuainan232001China School of Safety Science and Engineering Anhui University of Science and TechnologyHuainan232001China

In order to study the problems of unreasonable airflow distribution and serious dust pollution in a heading surface,an experimental platform for forced ventilation and dust removal was built based on the similar *** the similar experiment and numerical simulation,the distribution of airflow field in the roadway and the spatial and temporal evolution of dust pollution under the conditions of forced ventilation were *** airflow field in the roadway can be divided into three zones:jet zone,vortex zone and reflux *** dust concentration gradually decreases from the head to the rear of the *** the forced ventilation conditions,there is a unilateral accumulation of dust,with higher dust concentrations away from the *** position of the equipment has an interception effect on the *** maximum error between the test value and the simulation result is 12.9%,which verifies the accuracy of the experimental *** research results can provide theoretical guidance for the application of dust removal technology in coal mine.

关键词： Heading surface Forced ventilation Airflow field Dust pollution

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

Different mechanisms underlie similar species-area relationships in two tropical archipelagoes

引用

Plant Diversity 2024年第2期46卷 238-246页

作者： Shengchun Li Tieyao Tu Shaopeng Li Xian Yang yong zheng Liang-Dong Guo Dianxiang Zhang Lin jiang Key Laboratory of Plant Resources Conservation and Sustainable Utilization South China Botanical GardenChinese Academy of SciencesGuangzhou 510650China ECNU-Alberta Joint Lab for Biodiversity Study Tiantong Forest Ecosystem National Observation and Research StationSchool of Ecological and Environmental SciencesEast China Normal UniversityShanghai 200241China School of Biological Sciences Georgia Institute of TechnologyAtlantaGA 30332USA jiangxi Academy of Forestry Nanchang 330032China Institute of Eco-Chongming(IEC) Shanghai 202162China State Key Laboratory of Biocontrol School of EcologySun Yat-sen UniversityGuangzhou 510275China School of Geographical Sciences Fujian Normal UniversityFuzhou 350007China State Key Laboratory of Mycology Institute of MicrobiologyChinese Academy of SciencesBeijing 100101China

Despite much research in the field of island biogeography,mechanisms regulating insular diversity remain ***,we aim to explore mechanisms underlying plant species-area relationships in two tropical archipelagoes in the South China *** found positive plant species-area relationships for both coral and continental ***,our results showed that different mechanisms contributed to similar plant species-area relationships between the two *** coral islands,soil nutrients and spatial distance among communities played major roles in shaping plant community structure and species *** contrast,the direct effect of island area,and to a lesser extent,soil nutrients determined plant species richness on continental ***,increasing soil nutrients availability(N,P,K)had opposite effects on plant diversity between the two *** summary,the habitat quality effect and dispersal limitation are important for regulating plant diversity on coral islands,whereas the passive sampling effect,and to a lesser extent,the habitat quality effect are important for regulating plant diversity on continental *** generally,our findings indicate that island plant species-area relationships are outcomes of the interplay of both niche and neutral processes,but the driving mechanisms behind these relationships depends on the type of islands.

关键词： Coral and continental islands Plant diversity Soil nutrients Species-area relationships The sampling effect

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

On the Strong Approximation for a Simple Reentrant Line in Light Traffic Under First-buffer First-served Service Discipline

引用

Acta Mathematicae Applicatae Sinica 2024年第3期40卷 823-839页

作者： Kai-ming YANG yong-jiang GUO School of Science Beijing University of Posts and TelecommunicationsBeijing 100876China

For a 2-station and 3-class reentrant line under first-buffer first-served(FBFS)service discipline in light traffic,we firstly construct the strong approximations for performance measures including the queue length,workload,busy time and idle time *** on the obtained strong approximations,we use a strong approximation method to find all the law of the iterated logarithms(LILs)for the above four performance measures,which are expressed as some functions of system parameters:means and variances of interarrival and service times,and characterize the fluctuations around their fluid approximations.

关键词： reentrant line queueing network FBFS service discipline strong approximation LIL Brownian motion

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

Immunobiology of COVID-19: Mechanistic and therapeutic insights from animal models

引用

Zoological Research 2024年第4期45卷 747-766页

作者： Hong-Yi zheng Tian-Zhang Song yong-Tang zheng State Key Laboratory of Genetic Evolution&Animal Models KIZ-CUHK Joint Laboratory of Bioresources and Molecular Research in Common DiseasesCenter for Biosafety Mega-ScienceKunming Institute of ZoologyChinese Academy of SciencesKunmingYunnan 650223China National Resource Center for Non-Human Primates National Research Facility for Phenotypic&Genetic Analysis of Model Animals(Primate Facility)Kunming Institute of ZoologyChinese Academy of SciencesKunmingYunnan 650107China

The distribution of the immune system throughout the body complicates in vitro assessments of coronavirus disease 2019(COVID-19)immunobiology,often resulting in a lack of reproducibility when extrapolated to the whole ***,developing animal models is imperative for a comprehensive understanding of the pathology and immunology of severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)*** review summarizes current progress related to COVID-19 animal models,including non-human primates(NHPs),mice,and hamsters,with a focus on their roles in exploring the mechanisms of immunopathology,immune protection,and long-term effects of SARS-CoV-2 infection,as well as their application in immunoprevention and immunotherapy of SARS-CoV-2 *** among these animal models and their specific applications are also highlighted,as no single model can fully encapsulate all aspects of *** effectively address the challenges posed by COVID-19,it is essential to select appropriate animal models that can accurately replicate both fatal and non-fatal infections with varying courses and *** animal model libraries and associated research tools is key to resolving the global COVID-19 pandemic,serving as a robust resource for future emerging infectious diseases.

关键词： SARS-CoV-2 COVID-19 Animal models Infection immunology Immunotherapy

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

Feedback processing in the primate brain and in AI systems

引用

Science China Technological Sciences 2024年第8期67卷 2297-2309页

作者： jiang yong HE Sheng Institute of Biophysics Chinese Academy of Sciences University of Chinese Academy of Sciences Institute of Artificial Intelligence Hefei Comprehensive National Science Center

The primate brain and artificial intelligence(AI) can both be conceptualized as information processing systems, each with its own distinct biological and computational architectures. While there are parallels between them, their respective structural and functional connections show significant differences. In this paper, we examine the central role of feedback processing in both the primate brain and AI systems, which has been shown to be crucial in shaping neural processing. By reviewing the key features of feedback processes in the primate brain, which allows the brain to incorporate prior knowledge, contextual information, and taskdemands into early-stage processing, we highlight the divergence in goals and functions between biological and AI *** these differences is crucial for elucidating the cognitive capabilities of the primate brain and for addressing computational challenges in AI. In advocating “Cognition-Inspired-Computation”, we suggest that integrating insights from feedback processing in the primate brain into AI research will offer potentially significant improvements for the advancement of AI systems.

关键词： cognitive neuroscience artificial intelligence feedback processing attention learning

来源：

同方期刊数据库

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

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：