检索结果-南通市图书馆

Particuology 2024年第4期87卷 1-19页

作者： Qiuhua Miao Wenchang zhu Yudong Cao Peng huang Chaobin hu Minping jia School of Mechanical Engineering Southeast UniversityNanjing211189China jiangsu Key Laboratory for Elevator Inteligent Safety Changshu215500China

Particle mixing and segregation are common phenomena in rotary drums,which are challenging to be controlled and driven artificially in powder *** this work,the discrete element method(DEM)was applied to construct the novel rotary drum composed of different shaped curved *** varying the operation parameters of particle and sidewall shapes as well as the length-to-diameter(L/D)ratio of drums,the axial mixing and segregation processes of binary size-induced particles were *** results show that the axial flow velocity of the particle mixtures is noticeably weakened once the particle angularity increases,making the non-spherical particles to mix better in rotary drums compared to the spherical ***,in the short drums with size-induced spherical particles,the axial segregation characteristics are significantly enhanced by the convex sidewalls while suppressed by the concave ***,for size-induced non-spherical particles,the axial segregation structure can be present in rotary drums with plane and concave sidewalls while not in drums with convex ***,the axial segregation band structure of spherical particles eventually increases proportionally with the increased drum L/D *** contrast,the non-spherical particles cannot form obvious multi-proportional segregation bands.

关键词： Axial flow behaviors Size-induced particles Curved sidewalls Non-spherical particles Rotary drum

Tracing the Medieval Culture through Shakespeare： A Review

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Fudan Journal of the humanities and Social Sciences 2013年第3期6卷 163-167页

作者： hu jia-zhu

When I first encountered the title of this book, Shakespeare and the Medieval World, my reaction was almost exactly as the author expected：＂blankness＂（6）. Since Shakespeare＇s works are labeled as English Renai... 详细信息

关键词：莎士比亚展望文化追踪中世纪时期文艺复兴

Designing hierarchical structures for innovative cooling textile

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Nano Research 2024年第10期17卷 9202-9224页

作者： Xiran Du Jinlei Li Bin zhu jia zhu National Laboratory of Solid State Microstructures College of Engineering and Applied SciencesJiangsu Key Laboratory of Artificial Functional MaterialsNanjing UniversityNanjing 210023China School of Sustainable Energy and Resources Nanjing UniversitySuzhou 215163China

The potential of personal cooling technologies in reducing air conditioning energy consumption and enhancing human thermal comfort is *** review focuses on recent advancements in hierarchical structure design for innovative cooling *** with insights into fundamental heat transfer processes between the human body,textile,and the surroundings,we uncover key control *** the advanced hierarchical structure designs enabling effective radiation,sweat evaporation,conduction management,and integration of cold energy sources for realizing effective human body cooling are systematically ***,we explore multifunctional designs beyond cooling,including switchable cooling-heating and ***,we engage in discussions on unifying cooling performance tests and additional multiple requirements to make strides toward practical *** review is anticipated to be a valuable resource,providing the scientific and industrial communities with a quick grasp of past advancements,current challenges,and future directions in achieving effective human body cooling.

关键词： thermal comfort personal cooling textile hierarchical structures

Chemoselective epoxidation of electron-deficient olefins with molecular oxygen via conjugated olefins epoxidation and BHT hydroxylation

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Science China Chemistry 2024年第9期67卷 3012-3018页

作者： jia Nie huanfeng jiang Chuanle zhu School of Chemistry and Chemical Engineering Key Lab of Functional Molecular Engineering of Guangdong ProvinceSouth China University of TechnologyGuangzhou 510640China Guangdong Provincial Key Laboratory of Technique and Equipment for Macromolecular Advanced Manufacturing South China University of TechnologyGuangzhou 510640China

The chemoselective epoxidation of electron-deficient olefins in the presence of electron-rich alkene moieties is *** chemoselective epoxidation strategy undergoes a conjugated olefin epoxidation and BHT hydroxylation process to give various useful oxiranes in high yields,especially for the 2-substituted ***,this protocol features mild conditions,is transition-metal free,operationally simple,and gram-scalable,and tolerates diverse functional *** candidate HSD-16 is synthesized smoothly by this *** studies indicate molecular oxygen is the terminal oxidant and the O-source of the oxiranes.

关键词： chemoselective epoxidation alkene fluorine molecular oxygen

同方期刊数据库

A compact X-band backward traveling-wave accelerating structure

在线全文

学校读者我要写书评

暂无评论

Nuclear Science and Techniques 2024年第5期35卷 13-29页

作者： Xian-Cai Lin Hao Zha jia-Ru Shi Qiang Gao Fang-Jun hu Qing-zhu Li huai-Bi Chen Department of Engineering Physics Tsinghua UniversityBeijing 100084China Key Laboratory of Particle and Radiation Imaging(Tsinghua University) Ministry of EducationBeijing 100084China

Very high-energy electrons(VHEEs)are potential candidates for FLASH radiotherapy for deep-seated *** proposed a compact VHEE facility based on an X-band high-gradient high-power *** this study,we investigated and realized the first X-band backward traveling-wave(BTW)accelerating structure as the buncher for a VHEE facility.A method for calculating the parameters of single cell from the field distribution was introduced to simplify the design of the BTW ***-domain circuit equations were applied to calculate the transient beam parameters of the buncher in the unsteady state.A prototype of the BTW structure with a thermionic cathode-diode electron gun was designed,fabricated,and tested at high power at the Tsinghua X-band high-power test *** structure successfully operated with 5-MW microwave pulses from the pulse compressor and outputted electron bunches with an energy of 8 MeV and a pulsed current of 108 mA.

关键词： Backward traveling-wave accelerating structure Equivalent circuit model High-power test Very high-energy electron radiotherapy

Design method and experimental study of a cathode tool with an extremely high leveling ratio for electrochemical machining of blisk

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Aeronautics 2024年第4期37卷 593-608页

作者： Moqi SHEN jia LIU Jingtao WANG Di zhu College of Mechanical and Electrical Engineering Nanjing University of Aeronautics and AstronauticsNanjing 210016China

To obtain final parts with the desired dimensional accuracy and repeatability via electrochemical machining(ECM), the machining process must enter an ECM balanced state. However,for the ECM processing of blisk, a key component of aerospace engines, the surface of the blade blank often has an uneven allowance distribution due to the narrow passage of the cascade. It is difficult to remedy this issue in subsequent processing steps, which is necessary to ensure the dimensional accuracy and repeatability of the final blade profile. To solve this problem, electrolytic machining must be preceded by electrolytic shaping, which requires cathode tools with large leveling ratios to quickly homogenize the blank surface of the blade. In this study, to obtain a cathode tool with an extremely high leveling ratio, a design method based on the variation in the electrode gap in the non-equilibrium electrolytic state is proposed, and a dissolution model based on the nonequilibrium state is established. In this design method, the allowance on the blank to be machined is first divided into many discrete allowances with the normal direction. The initial machining clearance, feed rate, and total machining time are then calculated using classical ECM equilibrium state theory based on the maximum allowance. Meanwhile, the point coordinates of the cathode tool at maximum allowance can be determined. The non-equilibrium model can then be used to calculate the relative coordinate positions corresponding to the remaining discrete allowances. Finally, the entire cathode tool profile is designed. Simulations, fundamental experiments, and blisk unit workpiece experiments were carried out to validate the design approach. In the simulated processing of the plane workpiece, the leveling ratio of the cathode tool designed by the proposed method(0.77)was 83% higher than that of the cathode tool designed using the traditional method. The simulation results were confirmed by processing experiments. In t

关键词： Electrochemical machining(ECM) Non-equilibrium machining Large leveling ratios Cathode design Finite element simulation Blisk

nifH Promoter Activity Is Regulated by DNA Supercoiling in Sinorhizobium meliloti

在线全文

学校读者我要写书评

暂无评论

Acta Biochimica et Biophysica Sinica 2005年第4期37卷 221-226页

作者： Yan-Jie LIU Biao hu jia-Bi zhu Shan-Jiong SHEN Guan-Qiao YU National Laboratory of Plant Molecular Genetics,Institute of Plant Physiology and Ecology,Shanghai Institutes for Biological Sciences,Chinese Academy of Sciences,Shanghai 200032,China National Laboratory of Plant Molecular Genetics Institute of Plant Physiology and Ecology Shanghai Institutes for Biological Sciences Chinese Academy of Sciences Shanghai 200032 China

In prokaryotes,DNA supercoiling regulates the expression of many genes;for example,theexpression of Klebsiella pneumoniae nifLA operon depends on DNA negative supercoiling in anaerobicallygrown cells,which indicates that DNA supercoiling might play a role in gene regulation of the *** the expression of the nifH promoter in Sinorhizobium meliloti is not repressed by oxygen,itis proposed that the status of DNA supercoiling may not affect the expression of the nifH *** this hypothesis by analyzing nifH promoter activity in wild-type and gyr Escherichia coli in thepresence and absence of DNA gyrase *** results show that gene expression driven by the *** nifH promoter requires the presence of active DNA *** DNA gyrase increases thenumber of negative superhelical turns in DNA in the presence of ATP,our data indicate that negativesupercoiling is also important for nifH promoter *** study also shows that the DNA supercoiling-dependent *** nifH promoter activity is related to the trans-acting factors NtrC and NifA that *** supercoiling appeared to have a stronger effect on NtrC-activated nifH promoter activity than onNifA-activated promoter ***,these results from the *** nifH promoter model systemseem to indicate that,in addition to regulating gene expression during anaerobic signaling,DNA supercoilingmay also provide a favorable topology for trans-acting factor binding and promoter activation regardless ofoxygen status.

关键词： nifH DNA supercoiling gyrase Sinorhizobium meliloti gene expression

Relationships between blood chromium exposure and liver injury:Exploring the mediating role of systemic inflammation in a chromate-exposed population

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Journal of Environmental Sciences 2024年第9期143卷 224-234页

作者： Zekang Su Yali Zhang Shiyi Hong Qiaojian Zhang jiayu Xu Guiping hu Xiaojun zhu Fang Yuan Shanfa Yu Tianchen Wang Guang jia Department of Occupational and Environmental Health Sciences School of Public HealthPeking UniversityBeijing 100191China School of Engineering Medicine and Beijing Advanced Innovation Center for Big Data-Based Precision Medicine Beihang UniversityBeijing 100191China National Center for Occupational Safety and Health Beijing 102308China Department of Occupational Health and Radiological Health Chongqing Centers for Disease Control and PreventionChongqing 400042China Henan Institute for Occupational Medicine Zhengzhou 450052China Department of Clinical Laboratory Third Hospital of Peking UniversityBeijing 100191China

Hexavalent chromium and its compounds are prevalent pollutants,especially in the work environment,pose a significant risk for multisystem toxicity and *** it is known that chromium accumulation in the liver can cause damage,the dose-response relationship between blood chromium(Cr)and liver injury,as well as the possible potential toxic mechanisms involved,remains poorly *** address this,we conducted a follow-up study of 590 visits from 305 participants to investigate the associations of blood Cr with biomarkers for liver injury,including serum alanine aminotransferase(ALT),aspartate aminotransferase(AST),total bilirubin(TBIL),and direct bilirubin(DBIL),and to evaluate the mediating effects of systemic ***(PLT)and the platelet-to-lymphocyte ratio(PLR)were utilized as biomarkers of systemic *** the linear mixed-effects analyses,each 1-unit increase in blood Cr level was associated with estimated effect percentage increases of 0.82%(0.11%,1.53%)in TBIL,1.67%(0.06%,3.28%)in DBIL,0.73%(0.04%,1.43%)in ALT and 2.08%(0.29%,3.87%)in AST,***,PLT mediated 10.04%,11.35%,and 10.77%increases in TBIL,DBIL,and ALT levels induced by chromate,*** addition,PLR mediated 8.26%and 15.58%of the association between blood Cr and TBIL or *** findings shed light on the mechanisms underlying blood Cr-induced liver injury,which is partly due to worsening systemic inflammation.

关键词： Blood chromate Liver injury Systemic inflammation Mediation analysis

Distributed order estimation for continuous-time stochastic systems

在线全文

学校读者我要写书评

暂无评论

Control Theory and Technology 2024年第3期22卷 406-418页

作者： Xinghua zhu Zhixin Liu Xiaoming hu Key Laboratory of Systems and Control Academy of Mathematics and Systems ScienceBeijing 100190China School of Mathematical Sciences University of Chinese Academy of SciencesBeijing 100190China Department of Mathematics KTH Royal Institute of TechnologyStockholm 10044Sweden

In this paper,we investigate the distributed estimation problem of continuous-time stochastic dynamic systems over sensor networks when both the system order and parameters are *** propose a local information criterion(LIC)based on the L_(0)penalty *** minimizing LIC at the diffusion time instant and utilizing the continuous-time diffusion least squares algorithm,we obtain a distributed estimation algorithm to simultaneously estimate the unknown order and the parameters of the *** dealing with the effect of the system noises and the coupling relationship between estimation of system orders and parameters,we establish the almost sure convergence results of the proposed distributed estimation ***,we give a simulation example to verify the effectiveness of the distributed algorithm in estimating the system order and parameters.

关键词： Stochastic differential equations Sensor networks Distributed order estimation Cooperative excitation condition.Convergence

Mapping out the reaction network of humin formation at the initial stage of fructose dehydration in water

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Green Energy & Environment 2024年第6期9卷 1016-1026页

作者： Xing Fu Yexin hu Ping hu hui Li Shuguang Xu Liangfang zhu Changwei hu Key Laboratory of Green Chemistry and Technology Ministry of EducationCollege of ChemistrySichuan UniversityChengduSichuan610064China State Key Laboratory of Southwestern Chinese Medicine Resources Innovative Institute of Chinese Medicine and PharmacyChengdu University of Traditional Chinese MedicineChengduSichuan611137China

The formation of humins hampers the large-scale production of 5-hydroxymethylfurfural(HMF)in ***,a detailed reaction network of humin formation at the initial stage of fructose-to-HMF dehydration in water is delineated by combined experimental,spectroscopic,and theoretical *** bimolecular reaction pathways to build up soluble humins are *** is,the intermolecular etherification of β-furanose at room temperature initiates the C12 path,whereas the C-C cleavage of a-furanose at 130-150℃ leads to C11 path,and that of open-chain fructose at 180℃ to C11' *** successive intramolecular dehydrations and condensations of the as-formed bimolecular intermediates lead to three types of soluble *** show that the C12 path could be restrained by using HCl or AlCl_(3) catalyst,and both the C12 and C110 paths could be effectively inhibited by adding THF as a co-solvent or accelerating heating rate via microwave heating.

关键词： Carbohydrates 5-hydroxymethylfurfural Reaction network Soluble humins Tautomer