检索结果-南通市图书馆

Cigarette Use and Secondhand Smoke Exposure Among Secondary School Students—China,2023

在线全文

学校读者我要写书评

暂无评论

China CDC weekly 2024年第22期6卷 509-515页

作者： Xinying zeng Shiwei Liu Lin Xiao Tobacco Control Office Chinese Center for Disease Control and PreventionBeijingChina

What is already known about this topic?In 2021,the prevalence of experimental and current cigarette use among secondary school students in China stood at 16.7%and 4.7%,***,39.9%of these students were exposed to secondhand smoke at *** is added by this report?In comparison to 2021,the prevalence of current cigarette use remained unchanged at 4.2%in 2023,whereas experimental use declined to 13.7%.Notably,rates were significantly higher among vocational senior high school(VSHS)students relative to their peers in senior high school(SHS)and junior high school(JHS).Furthermore,exposure to secondhand smoke in schools decreased to 35.4%in 2023 from previously recorded levels,with more pronounced reductions observed in JHS and SHS populations and no notable change among VSHS *** are the implications for public health practice?Targeted tobacco control policies are imperative for secondary school students,including the establishment of smoke-free school ***,it is crucial to pay close attention to the needs of VSHS students.

关键词： smoke unchanged senior

Influence of oxygen-rich hot air composite gas medium on sintering performance and function mechanism

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Iron and Steel Research International 2024年第5期31卷 1071-1081页

作者： Min Gan Hao-xiang Zheng Xiao-hui Fan Zhi-yun Ji Qiang Li Ming Wu Yi-fan Wang Xiao-long Wang Yu-feng Wu Xu-ling Chen zeng-qing Sun Xiao-xian Huang School of Minerals Processing and Bioengineering Central South UniversityChangsha410083HunanChina Shanxi Taigang Stainless Steel Co. Ltd.Taiyuan030003ShanxiChina

Hot air sintering technology is used to improve the quality and production efficiency of sintered ***,the current thick layer condition highlights the disadvantage of the low oxygen potential of the hot air sintering ***,it is considered to use oxygen enrichment sintering to improve the environment of hot air *** sintering,hot air sintering,and oxygen-rich hot air sintering were compared through sintering cup experiments,and the influence of hot air and oxygen-rich hot air on sintering indexes was *** air reduced the vertical sintering velocity,while improved the yield and tumbler ***-rich hot air sintering contributed to improving the vertical sintering velocity while ensuring the quality of sintered ore,thus comprehensively improving production *** the action of hot air,the highest temperature of the sintering layer increased and the high-temperature holding time was *** oxygen enrichment,the combustion efficiency of fuels in the upper layer of materials was promoted,which optimized heat distribution in the middle and lower layers of materials and increased the content of calcium ferrite in the sintered ore,thus strengthening the sintering process.

关键词： Iron ore sintering Hot air sintering Oxygen enrichment Function mechanism

State of China’s climate in 2023

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Atmospheric and Oceanic Science Letters 2024年第5期17卷 54-60页

作者： Linhai Sun Xiaying Zhu Wei Li Wanxiu Ai Xianyan Chen Yundi Jiang ling Wang Xukai Zou Shanshan Zhao Hongling zeng Hailing Zhong National Climate Center China Meteorological AdministrationBeijingChina

China witnessed a warm and dry climate in *** annual surface air temperature reached a new high of 10.71℃,with the hottest autumn and the second hottest summer since ***,the annual precipitation was the second lowest since 2012,at 615.0 *** was less than normal from winter to summer,but more in *** with the annual condition,precipitation in the flood season from May to September was also the second lowest since 2012,which was 4.3%less than normal,with the anomalies in the central and eastern parts of China being higher in central areas and lower in the north and *** the contrary,the West China Autumn Rain brought much more rainfall than normal,with an earlier start and later *** there was less annual precipitation in 2023,China suffered seriously from heavy precipitation events and *** particular,from the end of July to the beginning of August,a rare,extremely strong rainstorm caused by Typhoon Dussuri hit Beijing,Tianjin,and Hebei,causing an abrupt alteration from drought to flood conditions in North *** contrast,Southwest China experienced continuous drought from the previous autumn to current *** early summer,North China and the Huanghuai region experienced the strongest high-temperature process since ***,there were more cold-air processes than normal impacting China,with the most severe of the year occurring in ***,in spring,there were more sand and dust occurrences in northern China.

关键词： Climate in China Hottest year Extreme events Dussuri

Second-order error analysis of the averaged L1 scheme L1 for time-fractional initial-value and subdiffusion problems

在线全文

学校读者我要写书评

暂无评论

Science China Mathematics 2024年第7期67卷 1641-1664页

作者： Jinye Shen Fanhai zeng Martin Stynes School of Mathematics Southwestern University of Finance and EconomicsChengdu611130China School of Mathematics Shandong UniversityJinan250100China Applied and Computational Mathematics Division Beijing Computational Science Research CenterBeijing100193China

Fractional initial-value problems(IVPs) and time-fractional initial-boundary value problems(IBVPs), each with a Caputo temporal derivative of order α ∈(0, 1), are considered. An averaged variant of the well-known L1 scheme is proved to be O(N^(-2)) convergent for IVPs on suitably graded meshes with N points, thereby improving the O(N^(-(2-α))) convergence rate of the standard L1 scheme. The analysis relies on a delicate decomposition of the temporal truncation error that yields a sharp dependence of the order of convergence on the degree of mesh grading used. This averaged L1 scheme can be combined with a finite difference or piecewise linear finite element discretization in space for IBVPs, and under a restriction on the temporal mesh width, one gets again O(N^(-2)) convergence in time, together with O(h^(2)) convergence in space,where h is the spatial mesh width. Numerical experiments support our results.

关键词： time-fractional subdiffusion averaged L1 scheme

Finite Groups with Some Bounded Codegrees

在线全文

学校读者我要写书评

暂无评论

Acta Mathematica Sinica,English Series 2024年第7期40卷 1778-1784页

作者： Dong Fang YANG Yu zeng Heng LV School of Mathematics and Statistics Southwest UniversityChongqing400715P.R.China Department of Mathematics Changshu Institute of TechnologyChangshu215500P.R.China

For a characterχof a finite group G,the number cod(χ) := ∣G:ker(χ)∣/χ(1)is called the codegree ofχ.In this paper,we give a solvability criterion for a finite group G depending on the minimum of the ratioχ(1)^(... 详细信息

关键词： Finite group codegree degree simple group

Optimal Time-of-use Pricing for Renewable Energy-powered Microgrids: A Multi-agent Evolutionary Game Theory-based Approach

在线全文

学校读者我要写书评

暂无评论

CSEE Journal of Power and Energy Systems 2024年第1期10卷 162-174页

作者： Yu zeng Yinliang Xu Xinwei Shen Hongbin Sun Tsinghua-Berkeley Shenzhen Institute.Tsinghua Shenzhen International Graduate School Tsinghua UniversityShenzhen 518055China Department of Electrical Engineering Tsinghua UniversityBeijing 100084China

While price schedules can help improve the economic efficiency of renewable energy-powered microgrids,timeof-use(TOU)pricing has been identified as an effective way for microgrid development,which is presently limited by its high *** this study,we propose an evolutionary game theoretic model to explore optimal TOU pricing for development of renewable energy-powered microgrids by applying a multi-agent system,that comprises a government agent,local utility company agent,and different types of consumer *** the proposed model,we design objective functions for the company and the consumers and obtain a Nash equilibrium using backward *** pricing strategies,namely,the TOU seasonal pricing and TOU monthly pricing,are evaluated and compared with traditional fixed *** numerical results demonstrate that TOU schedules have significant potential for development of renewable energy-powered microgrids and are recommended for an electric company to replace traditional fixed ***,TOU monthly pricing is more suitable than TOU seasonal pricing for microgrid development.

关键词： Game theory microgrid multi-agent system renewable energy time-of-use pricing

Control of electromechanical performance in 3D printing latticestructured BaTiO_(3) piezoelectric ceramics

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Advanced Ceramics 2024年第7期13卷 987-1001页

作者： Zhujun Jiang Yinghong Sun Jimin Chen Yong zeng Faculty of Materials and Manufacturing Beijing University of TechnologyBeijing 100124China Beijing Engineering Research Center of 3D Printing for Digital Medical Health Beijing University of TechnologyBeijing 100124China

Barium titanate(BaTiO_(3))piezoelectric ceramics with triply periodic minimal surface(TPMS)structures have been frequently used in filters,engines,artificial bones,and other fields due to their high specific surface area,high thermal stability,and good heat ***,only a limited number of studies have analyzed the effect of various parameters,such as different wall thicknesses and porosities of TPMS structures,on ceramic electromechanical *** this study,we first employed vat photopolymerization(VPP)three-dimensional(3D)printing technology to fabricate high-performance BaTiO_(3) *** investigated the slurry composition design and forming process and designed a stepwise sintering postprocessing technique to achieve a density of 96.3%and a compressive strength of 250±25 MPa,with the piezoelectric coefficient(d_(33))reaching 263 pC/***,we explored the influence of three TPMS structures,namely,diamond,gyroid,and Schwarz P,on the piezoelectric and mechanical properties of BaTiO_(3) ceramics,with the gyroid structure identified as exhibiting optimal ***,we examined the piezoelectric and mechanical properties of BaTiO_(3) ceramics with the gyroid structure of varying wall thicknesses and porosities,thus enabling the modulation of ceramic electromechanical performance.

关键词： three-dimensional(3D)printing piezoelectric ceramics porous structure mechanical properties electrical properties

Attitude-adjusting dynamical behavior of cubic rover on low-gravity testbed

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Astrodynamics 2024年第1期8卷 149-159页

作者： Bowen Jiang Muhammad Talha Hussain Xiangyuan zeng School of Automation Beijing Institute of TechnologyBeijing100081China

Cubic rovers that traverse by hopping systems are promising in low-gravity *** several analyses of the control methods and mobility of the cubic rover are available,investigations of its attitude-adjusting behavior are still *** study derives the dynamic equations of the two attitude-adjusting modes of the cubic rover,referred to as walking and *** relationships between the speed threshold and rotation angle of the cubic rover were investigated in both rigid and regolith environments using a self-designed low-gravity *** studies were conducted by considering the experimental and simulated *** results of this study can be interesting for roving mission planning when exploring planetary moons and small celestial bodies.

关键词： low-gravitytestbed attitude-adjusting motion cubic rover experimental study

Lake microbiome composition determines community adaptability to warming perturbations

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Ecological Processes 2024年第2期13卷 177-191页

作者： Xiaotong Wu Qixing Zhou Hui zeng Xiangang Hu Key Laboratory of Pollution Processes and Environmental Criteria (Ministry of Education) Carbon Neutrality Interdisciplinary Science Centre/College of Environmental Science and Engineering Nankai University

Background Microbial communities are crucial for ecosystems. A central goal of microbial ecological research is to simplify the biodiversity in natural environments and quantify the functional roles to explore how the ecosystems respond under different environmental conditions. However, the research on the stability and dynamics of lake microbes in response to repeated warming stress is *** To exclude confounding environmental factors, we conducted a 20-day repeated warming simulation experiment to examine the composition and function dynamics of lake microbial *** Experimental warming significantly altered the community structure of bacteria instead of fungi. Microbial community structure, together with microbial biomass, jointly regulated the function of microbial communities. The plummeting of aerobic denitrifiers Pseudomonadaceae decreased by 99%(P < 0.001) after high temperature, leading to reduced microbial nitrogen metabolism on nitrogen respiration and nitrate respiration. Under warming conditions, the microbial community with higher adaptability showed more positive correlations and less competitive relationships in co-occurrence networks to acclimate to *** Microbiome composition controlled carbon and nitrogen metabolism, thus determining lake microbial communities' adaptability to heat stress. This study extended our insights on the lake microbial community response and adaptability under warming drivers.

关键词： Temperature Environmental stress Bacteria Fungi Freshwater ecosystem