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Mechanical and damping performances of TPMS lattice metamaterials fabricated by laser powder bed fusion

China Foundry 2024年第4期21卷 327-333页

作者： Yan-peng Wei Huai-qian Li jing-jing Han Ying-chun Ma Hao-ran Zhou jing-chang Cheng Jian Shi Zhi-quan Miao Bo Yu Feng Lin National Key Laboratory of Advanced Casting Technologies Shenyang Research Institute of Foundry Co.Ltd.CAMShenyang 110022China Department of Mechanical Engineering Tsinghua UniversityBeijing 100084China Key Laboratory of Space Physics Beijing 100076China

Lattice metamaterials based on three-period minimum surface(TPMS)are an effective means to achieve lightweight and high-strength materials which are widely used in various fields such as aerospace and ***,its vibration and noise reduction,and damping properties have not been fully ***,in this study,the TPMS structures with parameterization were designed by the method of surface migration,and the TPMS structures with high forming quality was manufactured by laser powder bed fusion(LPBF).The mechanical properties and energy absorption characteristics of the beam and TPMS structures were studied and compared by quasi-static *** modal shapes of the beam lattice structures and TPMS structures were obtained by the free modal analysis,and the damping properties of two structures were obtained by modal *** the two structures after heat treatment with the same porosity of 70%,the yield strength of the beam lattice structure reaches 40.76 MPa,elastic modulus is 20.38 GPa,the energy absorption value is 32.23 MJ·m^(-3),the damping ratio is 0.52%.The yield strength,elastic modulus,energy absorption value,and damping ratio of the TPMS structure are 50.74 MPa,25.37 GPa,47.34 MJ·m^(-3),and 0.99%,*** results show that TPMS structures exhibit more excellent mechanical properties and energy absorption,better damping performance,and obvious advantages in structural load and vibration and noise reduction compared with the beam lattice structures under the same porosity.

关键词： lattice metamaterials TPMS energy absorption damping laser powder bed fusion

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Eco-friendly calcium alginate microspheres enable enhanced profile control and oil displacement

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Petroleum Science 2024年第3期21卷 1928-1943页

作者： Xiao-Han Zhang chang-jing Zhou Yuan-Xiang Xiao Bo Hui Yong-Gang Xie Yu-Bin Su Xin-Ru Li Jie Huang Mao-chang Liu International Research Center for Renewable Energy State Key Laboratory of Multiphase Flow in Power EngineeringXi'an Jiaotong UniversityXi'an710049ShaanxiPR.China Shaanxi Key Laboratory of Advanced Stimulation Technology for Oil&Gas Reservoirs School of Petroleum EngineeringXi'an Shiyou UniversityXi'an 710065ShaanxiPR.China Oil&Gas Technology Research Institute Changqing Oilfield Branch CompanyPetroChinaXi'an710021ShaanxiPR China Suzhou Academy of Xi'an Jiaotong University Suzhou215123JiangsuPR China

Polymer microspheres(PMs),such as polyacrylamide,have been widely applied for enhanced oil recovery(EOR),yet with environmental ***,we report a microfluid displacement technology containing a bio-based eco-friendly material,i.e.,calcium alginate(CaAlg)microspheres for *** dominant mechanisms responsible for EOR over Ca Alg fluid have been verified,including the microscopic oil displacement efficacy augmented by regulating capillary force(determined by the joint action of interfacial tension and wettability between different phases)and macroscopic sweep volume increment through profile control and mobility ratio *** comprehensive effectiveness can be further impacted when the CaAlg microsphere is embellished ulteriorly by using appropriate amount of sodium dodecyl sulfonate(SDS).The core flooding and nuclear magnetic resonance(NMR)tests demonstrate that CaAlg-SDS microsphere can balance the interphase property regulation(wettability alteration and IFT reduction)and rheology properties,enabling simultaneous profile control and oil *** introduction of SDS will have a negative impact on rheological properties,which is not favored for *** results show that the involvement of 4-m M SDS will provide the best behavior,with an EOR rate of 34.38%.This cost-effective and environmentally-friendly bio-microspherebased microfluidic displacement technology is expected to achieve“green”oil recovery in future oilfield exploitation.

关键词： Calcium alginate microspheres Wettability Interfacial tension Rheology Viscoelasticity Enhanced oil recovery(EOR)

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Risk assessment of oil and gas investment environment in countries along the Belt and Road Initiative

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Petroleum Science 2024年第2期21卷 1429-1443页

作者： Bao-Jun Tang chang-jing Ji Yu-Xian Zheng Kang-Ning Liu Yi-Fei Ma Jun-Yu Chen Center for Energy and Environmental Policy Research Beijing Institute of TechnologyBeijing100081China School of Management and Economics Beijing Institute of TechnologyBeijing100081China Collaborative Innovation Center of Electric Vehicles in Beijing BeijingChina Sustainable Development Research Institute for Economy and Society of Beijing BeijingChina Institute of Carbon Neutrality ShanghaiTech UniversityShanghai201210China

With the implementation of the Belt and Road Initiative, China is deepening its cooperation in oil and gas resources with countries along the Initiative. In order to better mitigate risks and enhance the safety of investments, it is of significant importance to research the oil and gas investment environment in these countries for China's overseas investment macro-layout. This paper proposes an indicator system including 27 indicators from 6 dimensions. On this basis, game theory models combined with global entropy method and analytic hierarchy process are applied to determine the combined weights, and the TOPSIS-GRA model is utilized to assess the risks of oil and gas investment in 76 countries along the Initiative from 2014 to 2021. Finally, the GM(1,1) model is employed to predict risk values for 2022-2025. In conclusion, oil and gas resources and political factors have the greatest impact on investment environment risk, and 12 countries with greater investment potential are selected through cluster analysis in conjunction with the predicted results. The research findings may provide scientific decisionmaking recommendations for the Chinese government and oil enterprises to strengthen oil and gas investment cooperation with countries along the Belt and Road Initiative.

关键词： Belt and Road Initiative Oil and Gas Investment Risk assessment

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Intermediate phase-assisted growth of CsPbBr_(3) for high performance of carbon-based perovskite solar cells

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Rare Metals 2024年第5期43卷 2222-2229页

作者： Bo-Yan Liu He-Ming Yang Yu-Dong Zuo Zhi-Hao Tao Jun-Chun Li Ya-jing chang Guo-Qing Tong Yang Jiang School of Materials Science and Engineering Hefei University of TechnologyHefei 230009China State Key Laboratory of Pulsed Power Laser Technology National University of Defense TechnologyHefei 230037China

CsPbBr_(3)inorganic perovskites have been regarded as the promising materials in the field of photo-voltaics because of the high tolerance against *** high energy barrier of phase transition from lead bromide(PbBr_(2))to CsPbBr_(3)perovskite and low solubility of perovskite in organic solvent impede the further improvement of device performance in terms of CsPbBr_(3)solar ***,an intermediate phase-assisted growth of CsPbBr_(3)perovskite was proposed by introducing tetraphenylphosphonium bromide(TPPB)as *** TPPB is expected to react with PbBr_(2)in organic solvent to form an intermediate phase of[***]-PbBr_(2),which not only effectively improves the crystallinity of PbBr2 crystals,but also greatly reduces the phase transition energy barrier,leading to uniform and compact CsPbBr_(3)perovskite films with large grain size and high *** combination with carbon electrode,the CsPbBr_(3)solar cells yield a champion device performance of 9.57%in comparison of pristine CsPbBr_(3)solar cells showing a low efficiency of 8.17%.Furthermore,the intermediate phaseassisted growth of CsPbBr_(3)-based solar cells displays an outstanding storage over720 h.

关键词： CsPbBr_(3) Perovskite solar cells Carbon electrode Hole transport layer free Intermediate phase

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Multivariate analysis of oral mucosal ulcers during orthodontic treatment

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World Journal of Clinical Cases 2024年第26期12卷 5868-5876页

作者： jing chang Xue Li The Fifth Clinic Peking University School and Hospital of StomatologyNational Center for StomatologyNational Clinical Research Center for Oral DiseasesNational Engineering Research Center of Oral Biomaterials and Digital Medical Devices Beijing 100081China

BACKGROUND Orthodontic treatment can easily cause local soft tissue reactions in the oral cavity of patients under mechanical stress,leading to oral mucosal ulcers and affecting their quality of *** present,only limited literature has explored the factors leading to oral ulcers in orthodontic treatment,and these research results are still *** To investigate the current status and related factors of oral mucosal ulcers during orthodontic treatment,aiming to provide a valuable reference for preventing this disease in clinical *** A total of 587 patients who underwent orthodontic treatment at the Peking University School of Stomatology and Hospital of Stomatology between 2020 and 2022 were selected and allocated to an observation or control group according to the incidence of oral mucosal ulcers during orthodontic therapy.A questionnaire survey was constructed to collect patient data,including basic information,lifestyle and eating habits,treatment details,mental factors,and trace element levels,and a comparative analysis of this data was performed between the two *** A logistic regression model with oral ulcers as the dependent variable was *** regression results showed that age(≥60 years:odds ratio[OR]:6.820;95%confidence interval[CI]:2.226–20.893),smoking history(smoking:OR:4.434;95%CI:2.527–7.782),toothbrush hardness(hard:OR:2.804;95%CI:1.746–4.505),dietary temperature(hot diet:OR:1.399;95%CI:1.220–1.722),treatment course(>1 year:OR:3.830;95%CI:2.203–6.659),and tooth brushing frequency(>1 time per day:OR:0.228;95%CI:0.138–0.377)were independent factors for oral mucosal ulcers(P1 year,tooth brushing frequency of≤1 time per day,and m

关键词： Orthodontic treatment Oral ulcers Multivariate Logistic regression Prevent disease

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Advancements in machine learning for material design and process optimization in the field of additive manufacturing

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China Foundry 2024年第2期21卷 101-115页

作者： Hao-ran Zhou Hao Yang Huai-qian Li Ying-chun Ma Sen Yu Jian shi jing-chang Cheng Peng Gao Bo Yu Zhi-quan Miao Yan-peng Wei National Key Laboratory of Advanced Casting Technologies Shenyang Research Institute of Foundry Co.Ltd.CAMShenyang 110022China Department of Mechanical Engineering Tsinghua UniversityBeijing 100084China Key Laboratory of Space Physics Beijing 100076China School of Materials Science and Engineering Nanyang Technological University639798Singapore

Additive manufacturing technology is highly regarded due to its advantages,such as high precision and the ability to address complex geometric ***,the development of additive manufacturing process is constrained by issues like unclear fundamental principles,complex experimental cycles,and high *** learning,as a novel artificial intelligence technology,has the potential to deeply engage in the development of additive manufacturing process,assisting engineers in learning and developing new *** paper provides a comprehensive overview of the research and applications of machine learning in the field of additive manufacturing,particularly in model design and process ***,it introduces the background and significance of machine learning-assisted design in additive manufacturing *** then further delves into the application of machine learning in additive manufacturing,focusing on model design and process ***,it concludes by summarizing and forecasting the development trends of machine learning technology in the field of additive manufacturing.

关键词： additive manufacturing machine learning material design process optimization intersection of disciplines embedded machine learning

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Topological edge and corner states of valley photonic crystals with zipper-like boundary conditions

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Chinese Physics B 2024年第4期33卷 480-491页

作者：沈云峰许孝芳孙铭周文佶常雅箐 School of Mechanical Engineering Jiangsu UniversityZhenjiang 212000China School of Optical and Electronic Information Suzhou City University&Suzhou Key Laboratory of BiophotonicsSuzhou 215104China

We present a stable valley photonic crystal(VPC)unit cell with C_(3v)symmetric quasi-ring-shaped dielectric columns and realize its topological phase transition by breaking mirror *** on this unit cell structure,topological edge states(TESs)and topological corner states(TCSs)are *** obtain a new type of wave transmission mode based on photonic crystal zipper-like boundaries and apply it to a beam splitter assembled from rectangular photonic crystals(PCs).The constructed beam splitter structure is compact and possesses frequency separation *** addition,we construct a box-shaped triangular PC structures with zipper-like boundaries and discover phenomena of TCSs in the corners,comparing its corner states with those formed by other *** on this,we explore the regularities of the electric field patterns of TESs and TCSs,explain the connection between the characteristic frequencies and locality of TCSs,which helps better control photons and ensures low power consumption of the system.

关键词： valley photonic crystal topological edge states topological corner states higher-order topological insulators topological phase transition

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基于DEA-Tobit模型的生猪产业绿色发展效率研究

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饲料研究 2024年第3期47卷 176-181页

作者：常静霞郑州科技学院河南郑州450000

近年来,生猪产业绿色化取得长足进展。为了解生猪产业绿色发展效率变化情况及相关影响因素,研究首先通过DEA模型对生猪产业绿色发展效率进行测算,研判样本期内生猪产业绿色发展效率变化情况;再利用面板Tobit模型分析生猪产业绿色发展效... 详细信息

近年来,生猪产业绿色化取得长足进展。为了解生猪产业绿色发展效率变化情况及相关影响因素,研究首先通过DEA模型对生猪产业绿色发展效率进行测算,研判样本期内生猪产业绿色发展效率变化情况;再利用面板Tobit模型分析生猪产业绿色发展效率的影响因素。结果表明:从时间维度观察,生猪产业绿色发展效率在研究期间展现出波动上升的趋势,而在2019年之后,这一趋势则趋于稳定并持续上升。若从空间角度审视,内蒙古、黑龙江等9个省份在生猪产业绿色发展效率方面的提升最为显著。进一步分析动态效率,我们发现规模效率在推动生猪产业绿色发展效率提升中起到了关键作用。此外,资源禀赋、经济发展水平、环境规制、开放程度、交通通达度和规模化水平等要素,均对生猪产业绿色发展效率产生了显著的正向影响,为其提升提供了强大的驱动力。资源禀赋、经济发展水平、环境规制、开放程度、交通通达度和规模化水平均可显著正向提升生猪产业绿色发展效率。因此,应从释放区域资源禀赋、差异化落实环境规制和推动规模化养殖等方面提高生猪产业绿色发展效率。

关键词： DEA-Tobit模型生猪产业绿色发展全要素生产率

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政府补贴下考虑持股合作战略的供应链减排动态协调方法

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控制与决策 2024年第4期39卷 1370-1378页

作者：王道平常敬雅北京科技大学经济管理学院北京100083

在政府补贴政策下,将持股合作战略引入供应链减排决策中,运用微分博弈理论研究供应链的最优决策和动态协调问题.构建集中式决策模型和持股合作前后的分散式决策模型,并分析持股比例和消费者低碳偏好对供应链最优决策、利润和政府补贴政... 详细信息

在政府补贴政策下,将持股合作战略引入供应链减排决策中,运用微分博弈理论研究供应链的最优决策和动态协调问题.构建集中式决策模型和持股合作前后的分散式决策模型,并分析持股比例和消费者低碳偏好对供应链最优决策、利润和政府补贴政策的影响.研究结果表明:持股合作战略会替代一部分政府补贴政策的作用,且供应链成员合作越密切,政府补贴效果越好.随着持股比例的增加,供应链总利润呈现“U”型变化,只有当持股比例满足一定条件时,供应链成员才愿意选择持股合作,且持股合作战略的实施能够实现供应链协调.消费者低碳偏好的提高会对企业减排产生激励作用,而政府作为政策的制定者不受消费者低碳偏好的影响.

关键词：政府补贴持股合作战略供应链减排动态协调微分博弈

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基于第一性原理的β-C_(3)N_(2)笼中原子嵌入引起的超硬磁性新材料设计

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Science China Materials 2024年第6期67卷 2032-2038页

作者：孙丽萍付波涛常景 College of Physics and Electronic Engineering Sichuan Normal UniversityChengdu 610068China College of Physics and Electronic Engineering Center for Computational SciencesSichuan Normal UniversityChengdu 610068China

基于第一性原理计算,我们通过将客体原子嵌入β-C_(3)N_(2)笼状结构的内在空腔中,预测了机械超硬和可控磁性的共存.以氢掺杂(H@β-C_(3)N_(2))和氟掺杂(F@β-C_(3)N_(2))为例,我们的研究表明两种掺杂构型是稳定的,并发现它们分别属于反... 详细信息

基于第一性原理计算,我们通过将客体原子嵌入β-C_(3)N_(2)笼状结构的内在空腔中,预测了机械超硬和可控磁性的共存.以氢掺杂(H@β-C_(3)N_(2))和氟掺杂(F@β-C_(3)N_(2))为例,我们的研究表明两种掺杂构型是稳定的,并发现它们分别属于反铁磁半导体和铁磁半金属.这些有趣的磁相变源于它们在费米能级周围独特的能带结构,并可通过具有半填充占据的3D Hubbard模型和Stoner模型很好地解释.此外,H@β-C_(3)N_(2)和F@β-C_(3)N_(2)的高维氏硬度(49.0和48.2 GPa)表明它们具有笼状超硬材料特征.因此,氢和氟在β-C_(3)N_(2)笼中的掺杂分别产生了一种新型的超硬反铁磁半导体和超硬铁磁半金属,这些材料在极端条件下具有潜在的应用前景.我们的工作为设计具有优异机械性能和磁性的新型高性能多功能材料提供了一种有效的策略,这可能会为超硬材料未来在自旋电子学的应用提供理论依据.

关键词： first-principles calculations clathrateβ-C_(3)N_(2) super-hard materials ferromagnetic semi-metal

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