检索结果-南通市图书馆

Collaborative control of fine particles and ozone required in China for health benefit

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

Frontiers of Environmental Science & Engineering 2023年第8期17卷 1-11页

作者： Ling Qi Zhige Tian nan Jiang Fangyuan Zheng Yuchen Zhao Yishuo Geng Xiaoli duan School of Energy and Environmental Engineering University of Science and Technology BeijingBeijing 100083China

PM2.5 concentration declined significantly nationwide,while O3 concentration increased in most regions in China in 2013–*** evidences proved that peak season O3 is related to increased death risk from non-accidental and respiratory *** on these new evidences,we estimate excess deaths associated with long-term exposure to ambient PM2.5 and O3 in China following the counterfactual analytic framework from Global Burden *** deaths from non-accidental diseases associated with long-term exposure to ambient O3 in China reaches to 579(95%confidential interval(CI):93,990)thousand in 2020,which has been significantly underestimated in previous *** addition,the increased excess deaths associated with long-term O3 exposure(234(95%CI:177,282)thousand)in 2013–2020 offset three quarters of the avoided excess deaths(302(95%CI:244,366)thousand)mainly due to PM2.5 exposure *** key regions(the North China Plain,the Yangtze River Delta and the Fen-Wei Plain),the former is even larger than the latter,particularly in 2017–*** benefit of PM2.5 concentration reduction offsets the adverse effects of population growth and aging on excess deaths attributed to PM2.5 *** of excess deaths associated with O3 exposure is mainly due to the strong increase of O3 concentration,followed by population *** the faster population aging process in the future,collaborative control,and faster reduction of PM2.5 and O3 are needed to reduce the associated excess deaths.

关键词： Excess deaths Long-term exposure Fine particle Ozone

Numerical modelling for leak oil flow in tunnel of the cave storage

在线全文

学校读者我要写书评

暂无评论

Petroleum 2021年第3期7卷 335-342页

作者： Jimiao duan Huishu Liu shuo Xu Jiang Li Tingao Shen Keyu Lin Hao Yan Department of Fuel Army Logistics University of PLAChongqing401331China Training Base Army Logistics University of PLAWuhan430035China

Oil storage in cavern tank is one of the important ways of oil *** than 80%of the oil tanks in the cave storage have been used for around 30 years in China and leakage accidents are likely to *** it occurs,the motor closing facilities preventing leakage spreading should be set *** leaking oil flow characteristic in tunnel must be known for setting up the motor closing *** on the open-channel unsteady flow theory,a numerical model of tank leakage coupling the oil flow in tunnel was developed,and the characteristic line method was used to solve the model under the given initial condition and boundary *** variation of the depth and flow rate with time of oil flowing in the tunnel can be *** order to verify the accuracy of model,the measurement data of high accuracy experimental system for unsteady open-channel flow were conducted to compare with the *** fully confirms the high precision of the numerical model and reflects the variation characteristics of each hydraulic parameter in the numerical model of unsteady open channel flow *** then,the leaking oil flow characteristic in tunnel was *** is that the farther from the leaking tank,the lower depth and flow rate of the oil in the tunnel ***,the effect of the size of oil tank crack on the depth and flow rate was *** greater size of crack makes the oil flow rate higher and the oil deeper in the tunnel and flow faster.

关键词： Cave storage Tunnel Unsteady flow Leaking Oil

在线全文

学校读者我要写书评

暂无评论

星形AB共聚物和A均聚物的共组装模拟研究

原子与分子物理学报 2025年第5期42卷 90-94页

作者：段润宇新疆大学物理科学与技术学院乌鲁木齐830017

具有独特结构的纳米粒子在高分子材料领域具有广泛的应用.本文采用耗散粒子动力学模型系统的研究了三臂星形AB二嵌段共聚物和A均聚物共混体系的共组装相行为.通过调节聚集体中星形共聚物浓度和AB嵌段的长度比有效地控制了AB/A共混体系... 详细信息

具有独特结构的纳米粒子在高分子材料领域具有广泛的应用.本文采用耗散粒子动力学模型系统的研究了三臂星形AB二嵌段共聚物和A均聚物共混体系的共组装相行为.通过调节聚集体中星形共聚物浓度和AB嵌段的长度比有效地控制了AB/A共混体系中聚集体的共组装形貌.预测了一些有趣的结构,比如,具有较厚壳层的核-壳-补丁结构、具有壳层的且中心凹陷的圆盘状结构以及不规则椭球的多室结构.本文还发现对于具有较长A嵌段的星形链,增大A均聚物在聚集体中的浓度能够消除聚集体内B嵌段形成的核;对于具有较短A嵌段的星形链,少量的A均聚物能够诱导聚集体共组装成具有长条状核的多室纳米粒子.

关键词：耗散粒子动力学星形二嵌段共聚物共组装纳米粒子

The Structure of Ammonium D,L-Tartrate

同方期刊数据库博看期刊评论

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Structural Chemistry 2001年第6期20卷 470-472页

作者： NIE Jing-Jing XU duan-Jun WU Jing-Yun CHIANG Michael Yen-nan Department of Chemistry Zhejiang University Department of Chemistry National Sun Yat-Sen University

The single crystals of the title compound NH4+C4H5O6- (C4H9NO6, Mr = 167.1) were obtained from a hot aqueous solution containing L-glutamine and D,L-tartaric acid in mole ratio1:1.5. The crystal belongs to monoclinic space group P21/c with a = 7.646(2), b = 7.804(2), c = 11.502(3)? ?= 102.26(2)o, V = 670.7(3)?, Z = 4, F(000) = 352, Dc = 1.655 ***-3, m(MoKa) = 0.16 mm-1, R = 0.035, wR = 0.094 for 1028 observed reflections (I>2s(I)). The enatiomeric anions of the tartrate with both (2S,3S)- and (2R,3R)-configuration co-exist in the unit cell. The carbon skeleton assumes a coplanar arrangement with a torsion angle of 181.5o. The three- dimensional H-bonding network exists in the crystal. While tartrate groups link each other by H-bonds between carboxyl and hydroxyl groups, the ammonium cations insert between the tartrate groups to form a sandwich-like crystal structure.

关键词： crystal structure ammonium tartrate H-bonding hydrolysis glutamine

Handedness inversion of chiral mesoporous silica: A diffuse-reflectance circular dichroism study

在线全文

学校读者我要写书评

暂无评论

Chinese Chemical Letters 2019年第1期30卷 139-142页

作者： nan Wang Ruiyu Lin Minzhao Xue Yingying duan Shun'ai Che School of Chemistry and Chemical Engineering State Key Laboratory of Composite Materials Shanghai Jiao Tong University School of Chemical Science and Engineering Tongji University

Chiral mesoporous silica ribbons and rods with inversed handedness have been synthesized with the same enantio pure N-acylaminoacidat temperatures of 0℃and 20℃ respectively. With involving Cu^(2+)and meso-tetra(4-sulfonatophenyl)porphyrin(TPPS) as probes, ribbons and rods revealed opposite signals in diffuse-reflectance circular dichroism(DRCD) spectra, indicating the existence of inversed supramolecular chiral imprintings through helical stacking of amphiphiles. The structural evolution was systematically studied by the freeze-dried products sampled at different time after the addition of silica precursors. The H-bonding-depended molecular orientation probably controls the chiral sense upon forming chiral molecular stacking, which would be the origin of such handedness inversion

关键词： Chirality Handedness inversion Circular dichroism Mesoporous Amphiphile Self-assembly

Understanding and designing magnetoelectric heterostructures guided by computation:progresses,remaining questions,and perspectives

在线全文

学校读者我要写书评

暂无评论

npj Computational Materials 2017年第1期3卷 304-324页

作者： Jia-Mian Hu Chun-Gang duan Ce-Wen nan Long-Qing Chen Department of Materials Science and Engineering Pennsylvania State UniversityUniversity ParkPA 16802USA Key Laboratory of Polar Materials and Devices Ministry of EducationEast China Normal UniversityShanghaiChina School of Materials Science and Engineering and State Key Lab of New Ceramics and Fine ProcessingTsinghua UniversityBeijing 100084China

Magnetoelectric composites and heterostructures integrate magnetic and dielectric materials to produce new functionalities,e.g.,magnetoelectric responses that are absent in each of the constituent materials but emerge through the coupling between magnetic order in the magnetic material and electric order in the dielectric *** magnetoelectric coupling in these composites and heterostructures is typically achieved through the exchange of magnetic,electric,or/and elastic energy across the interfaces between the different constituent materials,and the coupling effect is measured by the degree of conversion between magnetic and electric energy in the absence of an electric *** strength of magnetoelectric coupling can be tailored by choosing suited materials for each constituent and by geometrical and microstructural *** this article,we discuss recent progresses on the understanding of magnetoelectric coupling mechanisms and the design of magnetoelectric heterostructures guided by theory and *** outline a number of unsolved issues concerning magnetoelectric *** compile a relatively comprehensive experimental dataset on the magnetoelecric coupling coefficients in both bulk and thin-film magnetoelectric composites and offer a perspective on the data-driven computational design of magnetoelectric composites at the mesoscale microstructure level.

关键词： composites material coupling

Inverse kinematics model of parallel macro-micro manipulator system

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

Chinese Science Bulletin 2000年第24期45卷 2221-2226页

作者： WANG Wenli duan Baoyan LIU Hong nan Rendong PENG Bo School of Mechanical and Electronic Engineering Xidian UniversityXi’an 710071China Beijing Astronomy Observatory China Academy of SciencesBeijing 100012China

An improved design, which employs the integration of optic, mechanical and electronic technologies for the next generation large radio telescope, is presented in this note. The authors propose the concept of parallel macro-micro manipulator system from the feed support structure with a rough tuning subsystem based on a cable structure and a fine tuning subsystem based on the Stewart platform. According to the requirement of astronomical observation, the inverse kinematics model of this parallel macro-micro manipulator system is deduced. This inverse kinematics model is necessary for the computer-controlled motion of feed.

关键词： large radio telescope parallel manipulator kinematics.

Modulation of the octahedral structure and potential superconductivity of La3Ni2O7 through strain engineering

在线全文

学校读者我要写书评

暂无评论

Science China(Physics,Mechanics & Astronomy) 2025年

作者： Zihao Huo Zhihui Luo Peng Zhang Aiqin Yang Zhengtao Liu Xiangru Tao Zihan Zhang Shumin Guo Qiwen Jiang Wenxuan Chen Dao-Xin Yao Defang duan Tian Cui Key Laboratory of Material Simulation Methods & Software of Ministry of Education State Key Laboratory of Superhard Materials College of Physics Jilin University Center for Neutron Science and Technology Guangdong Provincial Key Laboratory of Magnetoelectric Physics and Devices State Key Laboratory of Optoelectronic Materials and Technologies School of Physics Sun Yat-sen University MOE Key Laboratory for Non-equilibrium Synthesis and Modulation of Condensed Matter Shaanxi Province Key Laboratory of Advanced Functional Materials and Mesoscopic Physics School of Physics Xi'an Jiaotong University Institute of High Pressure Physics School of Physical Science and Technology Ningbo University

The recent transport measurements of La3Ni2O7uncovered a“right-triangle”shape of the superconducting dome in the pressure-temperature （P-T） phase *** by this,we perform theoretical first-principles studies of La3Ni2O7with the pressure ranging from 0 to 100 ***,we reveal a pressure dependence of the Ni-d2zelectron density at the Fermi energy (nE Fz) that highly coincides with such *** this basis,we further explore the electronic structure under uniaxial *** tracking the stress response of nE Fz,we propose that superconductivity can be achieved by applying only～2 GPa of compression along the c *** idea is further exemplified from the perspectives of lattice distortion,band structure,Fermi surface and superconducting phase *** also discuss the possible charge modulation under the stress and provide an insight into the relation between nE Fzand the superconducting Tcin *** study provides new routes to the search of high-Tcsuperconductors in future experiments.

关键词：

Instrumented oscillographic study on impact toughness of an axle steel DZ2 with different tempering temperatures

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

International Journal of Minerals,Metallurgy and Materials 2024年第7期31卷 1590-1598页

作者： shuo Liu Peng Zhang Bin Wang Kaizhong Wang Zikuan Xu Fangzhong Hu Xin Bai Qiqiang duan Zhefeng Zhang Shi-changxu Innovation Center for Advanced Materials Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China School of Materials Science and Engineering University of Science and Technology of ChinaShenyang 110016China Technology Center Ma'anshan Iron and Steel Co.Ltd.Ma'anshan 243000China

Compared with the conventional Charpy impact test method,the oscillographic impact test can help in the behavioral analysis of materials during the fracture *** this study,the trade-off relationship between the strength and toughness of a DZ2 axle steel at various tempering temperatures and the cause of the improvement in impact toughness was *** tempering process dramatically influenced carbide precipitation behavior,which resulted in different aspect ratios of *** toughness improved along with the rise in tempering temperature mainly due to the increase in energy required in impact crack *** characteristics of the impact crack propagation process were studied through a comprehensive analysis of stress distribution,oscilloscopic impact statistics,fracture morphology,and carbide *** poor impact toughness of low-tempering-temperature specimens was attributed to the increased number of stress concentration points caused by carbide morphology in the small plastic zone during the propagation process,which resulted in a mixed distribution of brittle and ductile fractures on the fracture surface.

关键词： axle steel DZ2 tempering process impact toughness oscillographic impact test impact crack propagation carbides