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多重节点法并行求解大规模稀疏线性方程组

Acta Mechanica Sinica 2024年第4期40卷 159-171页

作者：王永庆刘彬 Applied Mechanics Laboratory Department of Engineering MechanicsTsinghua UniversityBeijing100084China

本文以弹性力学为例,提出了多重节点法用于求解大规模稀疏线性方程组.多重节点法利用叠加性将复杂问题分解为简单的子问题,并利用局部性减少计算量.粗节点刚度阵和子区域刚度阵在迭代时不变,使得多重节点法适合求解多工况问题.粗节点和... 详细信息

本文以弹性力学为例,提出了多重节点法用于求解大规模稀疏线性方程组.多重节点法利用叠加性将复杂问题分解为简单的子问题,并利用局部性减少计算量.粗节点刚度阵和子区域刚度阵在迭代时不变,使得多重节点法适合求解多工况问题.粗节点和细节点之间的映射关系通过求解局部有限元模型得到而非插值法,使得多重节点法能够快速求解复杂拓扑问题.为了加快收敛速度,提出了最优粗节点刚度阵,并基于正则化最小二乘法给出了其计算方法.大规模数值实验表明,多重节点法具有很好的可扩展性以及近似线性加速比.与主流算法如多重网格法相比,多重节点法在求解多工况问题时收敛速度更快.

关键词：正则化最小二乘法节点法细节点局部性多重网格法叠加性并行求解插值法

Quantifying the impacts of COVID-19 on Sustainable Development Goals using machine learning models

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Fundamental Research 2024年第4期4卷 890-897页

作者： Chenyang Shuai Bu Zhao Xi Chen Jianguo Liu Chunmiao Zheng Shen Qu Jian-Ping Zou Ming Xu School of Management science and Real Estate Chongqing UniversityChongqing 400044China bSchool for Environment and Sustainability University of MichiganAnn ArborMI 489United Stats Michigan Institute for Computational Discovery&engineering University of MichiganAnn ArborMI 48109United States College of Economics and Management Southwest UniversityChongqing 400044China Center for Systems Integration and Sustainability Department of Fisheries and WildlifeMichigan State UniversityEast LansingMI 48824United States Guangdong Provincial Key Laboratory of Soil and Groundwater Pollution Control School of Environmental Science and EngineeringSouthern University of Science and TechnologyShenzhen 518055China School of Management and Economics Beijing Institute of TechnologyBeijing 100081China Center for Energy&Environmental Policy Research Beijing Institute of TechnologyBejing 100081China Key Laboratory of Jiangxi Province for Persistent Plutants Control and Resources Recycle Nanchang Hangkong UniversityNanchang 330063China department of Civil and Environmental engineering University of MichiganAnn ArborMI 48109United States

The COvID-19 pandemic has posed severe threats to global sustainable ***,a comprehensive quantitative assessment of the impacts of COVID-19 on Sustainable Development Goals(SDGs)is still *** research quantified the post-COVID-19 SDG progress from 2020 to 2024 using projected GDP growth and population and machine learning models including support vector machine,random forest,and extreme gradient *** results show that the overall SDG performance declined by 7.7%in 2020 at the global scale,with 12 socioeconomic SDG performance decreasing by 3.0%-22.3%and 4 environmental SDG performance increasing by 1.6%-9.2%.By 2024,the progress of 12 SDGs will lag behind for one to eight years compared to their pre-COVID-19 trajectories,while extra time will be gained for 4 environment-related ***,the pandemic will cause more impacts on countries in emerging markets and developing economies than those on advanced economies,and the latter will recover more quickly to be closer to their pre-covID-19 trajectories by ***-COVID-19 economic recovery should emphasize in areas that can help decouple economic growth from negative environmental *** results can help government and non-state stakeholders identify critical areas for targeted policy to resume and speed up the progress to achieve SDGs by 2030.

关键词： Sustainable development goals COVID-19 Machine learning Global development Sustainable development assessment

化学气相沉积技术助力构建更好的锂硫电池（英文）

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science Bulletin 2024年第13期 2013-2016页

作者：宋英泽宋丽贤王梦蕾蔡文龙 State Key Laboratory of Environment-Friendly Energy Materials School of Materials and Chemistry Southwest University of Science and Technology School of Material science and engineering Henan University of Technology department of Advanced Energy Materials College of Materials Science and Engineering Sichuan University

The burgeoning demand for modern electronic devices and electric vehicles has driven the development of efficient, reliable, and environmentally friendly batteries [1,2]. Lithium–sulfur （Li–S）batteries with high theoretical capacity (1672 mA h g-1) and energy density (2600 W h kg-1), have garnered significant interest in both academic and industrial research [3,4]. However, the widespread production and commercialization of Li–S batteries are impeded by the inherent characteristics of sulfur and lithium, along with their complex electrochemical behaviors. Notably, challenges such as the polysulfide shuttle effect and the slow kinetics of the sulfur nucleation/decomposition reaction hinder capacity utilization and cycling stability.

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Erratum to:Soft multifunctional neurological electronic skin through intrinsically stretchable synaptic transistor

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nano Research 2024年第9期17卷 8652-8652页

作者： Pengcheng Zhu Shuairong Mu Wenhao Huang Zeye Sun Yuyang Lin Ke Chen Zhifeng Pan Mohsen Golbon Haghighi Roya Sedghi Junlei Wang Yanchao Mao Key Laboratory of Materials Physics of Ministry of Education School of Physics and MicroelectronicsZhengzhou UniversityZhengzhou 450001China School of mechanical and Power engineering Zhengzhou UniversityZhengzhou 450001China department of Chemistry Shahid Beheshti UniversityTehran ***Iran

The original article has been corrected due to the incorrect PDF uploaded by the vendor's production.

关键词： stretch intrinsic electronic

Determinants of Tobacco Cultivation and the Associated Impacts of Adoption in Hurungwe District, Zimbabwe

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Agricultural sciences 2024年第4期15卷 505-531页

作者： Spencer Sibanda Satoshi Tsuyuki department of Information and Computer sciences Graduate School of Science and Engineering Saitama University Saitama Japan department of Global Agricultural sciences Graduate School of Agricultural and Life Sciences The University of Tokyo Tokyo Japan

Tobacco is an essential cash crop in Zimbabwe and a strategic livelihood option for hundreds of thousands of rural households. However, the crop is linked to negative environmental, economic, and social impacts. The existing studies on tobacco cultivation in Zimbabwe present contradictory findings on the determinants and impacts of adoption, leaving unanswered questions about the crop’s sustainability impact in the country. This article investigates the determinants of smallholder farmers’ decisions to grow tobacco and the associated impacts of adoption. Random and purposive sampling were used to select 273 household surveys, including tobacco and non-tobacco smallholder farmers, and 56 expert interviews to answer the research questions. We employed regression models alongside expert interviews and document analysis to identify the determinants influencing the decision-making process of smallholder farmers in Zimbabwe regarding tobacco cultivation. Additionally, our investigation aimed to elucidate the perceived impacts associated with the adoption of this agricultural practice. The regression analysis indicated that the farmer’s age, education level, farming experience, family size, household income, and perceived high farm profitability are significant drivers of tobacco adoption. We also discovered divergent and convergent perceptions of the critical impacts of tobacco cultivation. The study highlights the need for proactive multi-stakeholder collaboration and sustainable financial arrangements to address the negative impacts of tobacco production. As the primary stakeholder responsible for regulating and promoting agricultural activities, the Zimbabwean government should provide meaningful financial support, increase access to credit, and ensure better market facilities for alternative crops to reduce the over-dependence on tobacco.

关键词： Tobacco Cultivation Determinants of Adoption Sustainability Impacts Economic Livelihood Stakeholder Perceptions

Effect of Blasting Stress Wave on Dynamic Crack Propagation

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工程与科学中的计算机建模(英文) 2024年第1期138卷 349-368页

作者： Huizhen Liu Duanying Wan Meng Wang Zheming Zhu Liyun Yang Key Laboratory for Old Bridge Detection&Reinforcement Technology of the Ministry of Transportation Beijing100088China School of Mechanics and Civil engineering China University of Mining and TechnologyBeijing100083China MOE Key Laboratory of Deep Underground science and engineering School of Architecture and EnvironmentSichuan UniversityChengdu610065China

Stress waves affect the stress field at the crack tip and dominate the dynamic crack ***,evaluating the influence of blasting stress waves on the crack propagation behavior and the mechanical characteristics of crack propagation is of great significance for engineering *** this study,ANSYS/LS-DYNA was used for blasting numerical simulation,in which the propagation characteristics of blasting stress waves and stress field distribution at the crack tip were closely ***,ABAQUS was applied for simulating the crack propagation path and calculating dynamic stress intensity factors(DSIFs).The universal function was calculated by the *** results show that:the compressive wave causes the crack to close and the reflected tensile wave drives the crack to initiate and propagate,and failure mode is mainly tensile *** crack propagation velocity varies with time,which increases at first and then decreases,and the crack arrest occurs due to the attenuation of stress waves and dissipation of the blasting *** addition,crack arrest toughness is smaller than the crack initiation toughness,applied pressure waveforms(such as the peak pressure,duration,waveforms,wavelengths and loading rates)have a great influence on *** is conducive to our deep understanding or the study of blasting stress waves dominated fracture,suggesting a broad reference for the further development of rock blasting in engineering practice.

关键词： Crack propagation blasting stress wave dynamic stress intensity factor pressure waveform numerical simulation

Interfacial molecular screening of polyimide dielectric towards high-performance organic field-effect transistors

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Chinese Chemical Letters 2024年第2期35卷 268-271页

作者： Yingshuang Zheng Huchao Li Ting Jiang Fei Jiao Jie Li Yong Lei Guofeng Tian Jinshun Bi Yundong Xuan Liqiang Li Deyang Ji Wenping Hu department of Chemistry Tianjin Key Laboratory of Molecular Optoelectronic SciencesInstitute of Molecular Aggregation ScienceTianjin UniversityTianjin 300072China GPL Photonics Laboratory State Key Laboratory of Applied OpticsChangchun Institute of OpticsFine Mechanics and PhysicsChinese Academy of SciencesChangchun 130033China Haihe Laboratory of Sustainable Chemical Transformations Tianjin 300192China department of Chemistry Tianjin Key Laboratory of Molecular Optoelectronic SciencesSchool of ScienceCollaborative Innovation Center of Chemical Science and EngineeringTianjin UniversityTianjin 300072China Joint School of National University of Singapore and Tianjin University Fuzhou 350207China Fachgebiet Angewandte nanophysik Institut für Physik & IMN MacroNanoTechnische Universität IlmenauIlmenau 98693Germany State Key Laboratory of Chemical Resource engineering Beijing University of Chemical TechnologyBeijing 100029China Institute of microelectronics Chinese Academy of SciencesBeijing 100029China University of Chinese Academy of sciences Beijing 100101China

The compatibility of the gate dielectrics with semiconductors is vital for constructing efficient conducting channel for high charge ***,it is still a highly challenging mission to clearly clarify the relationship between the dielectric layers and the chemical structure of semiconductors,especially vacuum-deposited small ***,interfacial molecular screening of polyimide(Kapton)dielectric in organic field-effect transistors(OFETs)is comprehensively *** is found that the semiconducting small molecules with alkyl side chains prefer to form a high-quality charge transport layer on polyimide(PI)dielectrics compared with the molecules without alkyl side *** this basis,the fabricated transistors could reach the mobility of 1.2 cm^(2) V^(−1)s^(−1) the molecule with alkyl side chains on bare PI *** is more,the compatible semiconductor and dielectric would further produce a low activation energy(E_(A))of 3.01 meV towards efficient charge transport even at low temperature(e.g.,100 K,0.9 cm^(2) V^(−1)s^(−1)).Our research provides a guiding scheme for the construction of high-performance thin-film field-effect transistors based on PI dielectric layer at room and low temperatures.

关键词： Interfacial molecular screening Polyimide dielectrics Organic semiconductors Interface engineering Thin-film transistors

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Bending Crashworthiness of Thin-Walled Square Tubes Partially Filled with Metallic Foams

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Journal of Harbin Institute of Technology(New series) 2024年

作者： Zhongyou Xie Limin Guo Cheng Li Jianwen Cai School of Architectural engineering Tongling University School of science Changzhou Institute of Technology School of Automotive engineering Changzhou Institute of Technology

Two cross-sectional configurations of thin-walled square tubes partially filled with lightweight metallic foams are proposed， and termed as double-cell configuration partially filled with foam (DC-PF) and double-tube configuration partially filled with foam (DT-PF)， respectively. The bending crashworthiness is investigated based on three-point bending tests using finite element ABAQUS/Explicit code. The two key mechanical indicators including Crash Load Efficiency (CLE) and Specific Energy Absorption (SEA) are introduced to evaluate the effect of foams in comparison with empty square tubes and fully filled square tubes. The numerical results show that the two partially filled configurations， especially DT-PF， display dramatically excellent bending crashworthiness compared to empty and fully filled square tubes. There exists a foam density threshold， beyond which the CLE of DT-PF achieves a maximum constant. In addition， there seems to be another foam density threshold， beyond which the SEA of DT-PF gets to the maximum value. It is also shown that the foam density threshold corresponding to the maximum SEA varies with the thickness of thin-walled square tubes.

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Biodegradable,strong,and clear wood package for plastic alternative

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nano Research 2024年第9期17卷 8531-8541页

作者： Jianfu Tang Xueqin Fan Haozhou Huang Xiaofei Dong Xueqi Li Peiru Wang Ran Yin Yanjun Xie Jian Li Gang Tan Zhenqian Pang Wentao Gan Key Laboratory of Bio-based Material science&Technology(Ministry of Education) Northeast Forestry UniversityHarbin 150040China department of Architecture College of Civil Engineering and ArchitectureZhejiang UniversityHangzhou 310027China Smart Materials for Architecture Research Lab Innovation Center of Yangtze River DeltaZhejiang UniversityJiaxing 314100China Heilongjiang Key Laboratory of Complex Traits and Protein Machines in Organisms Northeast Forestry UniversityHarbin 150040China

Using biodegradable material derived from renewable resources as petroleum-based plastics replacement is a promising way towards sustainable ***,the insufficient mechanical properties and complex manufacturing process of bioplastics still need to be improved for high-quality food ***,we report a top-down strategy to transform natural wood into a clear wood packaging film through scalable delignification and polyvinyl alcohol(PVA)*** wood packaging film demonstrates a laminated structure with completely collapsed cell walls and PVA intertwined together after energy-saving air drying,resulting in high light transmittance with low haze,good mechanical performance,and high barrier performance for oxygen and water *** dynamics simulations reveal the underlying fracture mechanism between cellulose and PVA,which effectively enhances the Young’s modulus and strength of the wood packaging *** findings contribute to the development of biodegradable and strong packaging materials,as well as other food-related applications,using sustainable wood.

关键词： wood food package mechanical enhancement plastic replacement biodegradability