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Simultaneously enhancing erosion and compression resistance:designing AlCoCrFeNi high-entropy alloy strengthened Ag-based contacts

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Rare Metals 2024年第9期43卷 4476-4492页

作者： Xiao-Yang Xue zhe Wang Hui-Ling Nie Zhao Yuan Jun Wang chang-Hu Xu Kai Wen Cong-Hao Yu School of Materials Science and Engineering Xi’an Polytechnic University School of Physics Xi’an Jiaotong University Key Laboratory of Pulsed Power Technology School of Electrical and Electronic EngineeringHuazhong University of Science and Technology State Key Laboratory of Advanced Electromagnetic Engineering and Technology School of Electrical and Electronic EngineeringHuazhong University of Science and Technology

Designing microstructures and unveiling dynamic erosion mechanisms remain important challenges for Ag-based contacts. To simultaneously enhance erosion and compression resistance, an Al Co Cr Fe Ni high-entropy alloy(HEA) is introduced into Ag-based materials to fabricate novel Ag-HEA contacts with island-and skeletonrestricted microstructures. The arc erosion experimental results reveal that the skeleton-restricted HEA microstructure is the key factor in reducing the hill and crater morphologies of the contact surface, effectively delaying material transfer between the movable and stationary contacts. The molten bridge evolution and compressive deformation behavior of Ag-HEA contacts with various microstructures are investigated using molecular dynamics(MD) simulations. MD results indicate that the constraint of Ag atom diffusion in the molten pool and the involvement of HEA atoms in the molten bridge are the primary mechanisms for improving erosion resistance. The skeleton-restricted HEA microstructure reduces the total energy and structural stability of the molten bridge system and promotes its fracture and disintegration. Moreover, the synergistic effect of the twin and Lomerz–Cottrell lock structures can hinder dislocation glide, generating dispersed and small-area stacking faults in the Ag matrix and mitigating the concentration of shear strains. Thus, the skeleton-restricted HEA microstructure contributes positively to compression resistance. This study presents a novel approach to designing Ag-based contacts.

关键词： Arc erosion Electrical contact materials High entropy alloys Microstructures Molecular dynamics

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Mechanisms of fracture propagation from multi-cluster using a phase field based HMD coupling model in fractured reservoir

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Petroleum Science 2024年第3期21卷 1829-1851页

作者： Yun-Jin Wang Bo Wang Hang Su Tu chang Ren-Cheng Dong Li-zhe Li Wei-Yu Tang Ting-Xue Jiang Fu-Jian Zhou State Key Laboratory of Petroleum Resources and Engineering China University of Petroleum-BeijingBejing2249China China University of Petroleum-Beijing at Karamay Karamay834000XinjiangChina China National Oil and Gas Exploration and Development Corporation Ltd. Beijing100034China University of Texas at Austin United States SINOPEC Research Institute of Petroleum Engineering Beijing100101China

Natural fractures(NFs)are common in shale and tight reservoirs,where staged multi-cluster fracturing of horizontal wells is a prevalent technique for reservoir *** NFs and stress interference are recognized as significant factors affecting hydraulic fracture(HF)propagation,the combined influence of these factors remains poorly *** address this knowledge gap,a novel coupled hydromechanical-damage(HMD)model based on the phase field method is developed to investigate the propagation of multi-cluster HFs in fractured *** comprehensive energy functional and control functions are established,while incorporating dynamic fluid distribution between multiple perforation clusters and refined changes in rock mechanical parameters during hydraulic *** HMD coupled multi-cluster HF propagation model investigates various scenarios,including single HF and single NF,reservoir heterogeneity,single HF and NF clusters,and multi-cluster HFs with NF *** results show that the HMD coupling model can accurately capture the impact of approach angle(θ),stress difference and cementation strength on the interaction of HF and *** criterion of the open and cross zones is not *** NF angle(a)is not a decisive parameter to discriminate the *** to the relationship between approach angle(θ)and NF angle(a),the contact relationship of HF can be divided into three categories(θ=a,θa).The connected NF can increase the complexity of HF by inducing it to form branch fracture,resulting in a fractal dimension of HF as high as2.1280 at angles of±45°.Inter-fracture interference from the heel to the toe of HF shows the phenomenon of no,strong and weak ***,under the influence of NFs,distant HFs from the injection can become dominant ***,as a gradually increases,inter-fracture stress interference becomes the primary factor influencing HF propagation,gradually superseding the dominance of NF

关键词： HMD coupling Phase field Natural fracture Flow distribution Hydraulic fracturing Inter-fracture interference

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产学研深度融合动态演化博弈机制研究——基于创新过程视角

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技术经济 2023年第9期42卷 24-40页

作者：常哲郭彬太原理工大学经济管理学院太原030024

产学研深度融合是完善我国科技创新体制机制系列部署中的关键环节,但现有研究未体现出深度融合过程的动态性、阶段性及多主体性等特征。鉴于此,将过程阶段思想引入产学研机制中,构建多方参与的产学研深度融合演化博弈模型,分析创新主体... 详细信息

产学研深度融合是完善我国科技创新体制机制系列部署中的关键环节,但现有研究未体现出深度融合过程的动态性、阶段性及多主体性等特征。鉴于此,将过程阶段思想引入产学研机制中,构建多方参与的产学研深度融合演化博弈模型,分析创新主体的策略选择,并用Matlab软件对主体行为策略的演化过程进行仿真研究。结果表明:地方政府的资金支持、政策支持及合理的惩罚机制均有助于深度融合,但是过多的资金支持会弱化地方政府的引导效应;基于相对风险分担的收益分配机制相比于平均分配、成本分配机制更符合创新主体的利益诉求;通过深度融合既能降低创新过程中的不确定性风险又能实现风险分担。最后,针对产学研深度融合机制的构建提出相关建议。

关键词：产学研深度融合创新过程演化博弈复制动态方程

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Constraining the anisotropy of the Universe with the Pantheon supernovae sample

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Chinese Physics C 2019年第12期43卷 180-187页

作者：常哲赵东周勇 Institute of High Energy Physics Chinese Academy of SciencesBeijing 100049China School of Physical Sciences University of Chinese Academy of SciencesBeijing 100049China

We test the possible dipole anisotropy of the Finslerian cosmological model and the other three dipolemodulated cosmological models,*** dipole-modulated ACDM,wCDM and Chevallier-Polarski-Linder(CPL)models,by using the recently released Pantheon sample of SNe *** Markov chain Monte Garlo(MGMC)method is used to explore the whole parameter *** find that the dipole anisotropy is very weak in all cosmological models *** the dipole amplitudes of four cosmological models are consistent with zero within the 1σuncertainty,the dipole directions are close to the axial direction of the plane of the SDSS subsample in *** may imply that the weak dipole anisotropy in the Pantheon sample originates from the inhomogeneous distribution of the SDSS subsample.A more homogeneous distribution of SNe la is necessary to constrain the cosmic anisotropy.

关键词： supernovae:general large-scale structure of the Universe cosmology

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Particles accelerated in Hertzian magnetic dipole field of a pulsar

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Chinese Physics C 2021年第11期45卷 136-142页

作者：常哲朱庆华 Institute of High Energy Physics Chinese Academy of SciencesBeijing 100049China University of Chinese Academy of Sciences Beijing 100049China

Supernova remnants are supposed to be the most possible sources of cosmic ***,alternative sources of cosmic rays,such as an active galactic nucleus,gamma-ray bursts,and pulsars,have not be *** this study,we investigate the possibility of cosmic rays being generated by *** pulsar is simply described as a rotational magnetic dipole,the so-called Hertzian magnetic dipole,an exact solution of the d'Alembert *** the rotational magnetic dipole field,charged particles experience an accelerated electric field with their radiation *** particles,which are initially static out of the light cylinder radius,can be accelerated up to a high energy.

关键词： pulsars cosmic rays acceleration of particles

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产业协同集聚对绿色创新效率的影响研究--基于空间溢出视角

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财经问题研究 2023年第10期 53-67页

作者：常哲仁郑梦江苏省社会科学院财贸研究所江苏南京210004 北京联合大学管理学院北京100101

本文基于2006—2019年中国285个地级市面板数据,采用时空双重固定空间杜宾模型系统地考察了产业协同集聚对绿色创新效率的影响。研究发现,产业协同集聚和绿色创新效率均具有明显的空间集聚特征。产业协同集聚不仅显著地提升了本地区城... 详细信息

本文基于2006—2019年中国285个地级市面板数据,采用时空双重固定空间杜宾模型系统地考察了产业协同集聚对绿色创新效率的影响。研究发现,产业协同集聚和绿色创新效率均具有明显的空间集聚特征。产业协同集聚不仅显著地提升了本地区城市绿色创新效率,还对邻近地区产生空间溢出效应。但空间溢出效应具有地理衰减特征,在312.2千米以内为空间溢出区域,687.2千米为空间溢出的地理阈值。产业协同集聚对绿色创新效率的空间影响存在时间异质性、区域异质性和行业异质性。在服务业综合改革试点前,产业协同集聚对绿色创新效率无影响;在服务业综合改革试点后,产业协同集聚不仅提升了本地区绿色创新效率,而且也产生了空间溢出效应;东部地区存在虹吸效应,中部地区存在涓滴效应,西部地区既不存在虹吸效应也不存在涓滴效应;不同类型生产性服务业与制造业协同集聚均能辐射邻近地区,中低端生产性服务业与制造业协同集聚并不能直接影响本地区绿色创新效率,但高端生产性服务业与制造业协同集聚可以显著提升本地区绿色创新效率。本文为进一步优化中国产业区域布局、提升城市绿色创新效率提供了决策参考。

关键词：产业协同集聚绿色创新效率空间杜宾模型地理衰减边界

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Redshift drift in uniformly accelerated reference frame

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Chinese Physics C 2020年第7期44卷 199-210页

作者：常哲朱庆华 Institute of High Energy Physics Chinese Academy of SciencesBeijing 100049China University of Chinese Academy of Sciences Beijing 100049China

We construct an alternative uniformly accelerated reference frame based on a 3+1 formalism in adapted *** this frame,a time-dependent redshift drift exists between co-moving observers,which differs from that in Rindle... 详细信息

关键词： non-inertial frame uniform acceleration redshift drift Unruh effect

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Early electrical field stimulation prevents the loss of spinal cord anterior horn motoneurons and muscle atrophy following spinal cord injury

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Neural Regeneration Research 2018年第5期13卷 869-876页

作者： Cheng Zhang Wei Rong Guang-Hao Zhang Ai-Hua Wang chang-zhe Wu Xiao-Lin Huo Beijing Key Laboratory of Bioelectromagnetism Institute of Electrical Engineering Chinese Academy of Sciences Beijing China Department of Orthopedics Beijing Tsinghua Changgung Hospital Medical Center Tsinghua University Beijing China University of Chinese Academy of Sciences Beijing China

Our previous study revealed that early application of electrical field stimulation（EFS） with the anode at the lesion and the cathode distal to the lesion reduced injury potential, inhibited secondary injury and was neuroprotective in the dorsal corticospinal tract after spinal cord injury（SCI）. The objective of this study was to further evaluate the effect of EFS on protection of anterior horn motoneurons and their target musculature after SCI and its mechanism. Rats were randomized into three equal groups. The EFS group received EFS for 30 minutes immediately after injury at T_（10）. SCI group rats were only subjected to SCI and sham group rats were only subjected to laminectomy. Luxol fast blue staining demonstrated that spinal cord tissue in the injury center was better protected; cross-sectional area and perimeter of injured tissue were significantly smaller in the EFS group than in the SCI group. Immunofluorescence and transmission electron microscopy showed that the number of spinal cord anterior horn motoneurons was greater and the number of abnormal neurons reduced in the EFS group compared with the SCI group. Wet weight and cross-sectional area of vastus lateralis muscles were smaller in the SCI group to in the sham group. However, EFS improved muscle atrophy and behavioral examination showed that EFS significantly increased the angle in the inclined plane test and Tarlov＇s motor grading score. The above results confirm that early EFS can effectively impede spinal cord anterior horn motoneuron loss, promote motor function recovery and reduce muscle atrophy in rats after SCI.

关键词： nerve regeneration spinal cord injury electrical field stimulation anterior horn motoneurons vastus lateralis muscle Tarlov's motor grading scale inclined plane test choline acetyltransferase transmission electron microscopy neural regeneration

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Predictive value of angiopoietin-like protein 8 in metabolic dysfunction-associated fatty liver disease and its progression:A case-control study

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World Journal of Diabetes 2024年第3期15卷 418-428页

作者： Lu-Lu Gan Can Xia Xuan Zhu Yue Gao Wen-chang Wu Qi Li Ling Li zhe Dai Yi-Min Yan Medical College Wuhan University of Science and TechnologyWuhan 430071Hubei ProvinceChina Department of Endocrinology Xiaogan Hospital Affiliated with Wuhan University of Science and TechnologyThe Central Hospital of XiaoganXiaogan 432000Hubei ProvinceChina Department of Endocrinology Zhongnan Hospital of Wuhan UniversityWuhan 430071Hubei ProvinceChina

BACKGROUND The prevalence of metabolic dysfunction-associated fatty liver disease(MAFLD)is rapidly increasing,currently affecting approximately 25%of the global *** fibrosis represents a crucial stage in the development of MAFLD,with advanced liver fibrosis elevating the risks of cirrhosis and hepatocellular *** serum markers are less effective in diagnosing liver fibrosis compared to more complex ***,imaging techniques like transient elastography face limitations in clinical application due to equipment and technical ***,it is imperative to identify a straightforward yet effective method for assessing MAFLD-associated liver *** To investigate the predictive value of angiopoietin-like protein 8(ANGPTL8)in MAFLD and its *** We analyzed 160 patients who underwent abdominal ultrasonography in the Endocrinology Department,Xiaogan Central Hospital affiliated to Wuhan University of Science and Technology,during September 2021-July *** abdominal ultrasonography and MAFLD diagnostic criteria,among the 160 patients,80 patients(50%)were diagnosed with *** MAFLD group was divided into the liver fibrosis group(n=23)and non-liver fibrosis group(n=57)by using a cut-off fibrosis-4 index≥*** regression was used to analyze the risk of MAFLD and the risk factors for its *** operating characteristic curves were used to evaluate the predictive value of serum ANGPTL8 in MAFLD and its *** Compared with non-MAFLD patients,MAFLD patients had higher serum ANGPTL8 and triglyceride-glucose(TyG)index(both P<0.05).Serum ANGPTL8(r=0.576,P<0.001)and TyG index(r=0.473,P<0.001)were positively correlated with *** ANGPTL8 was a risk factor for MAFLD[odds ratio(OR):1.123,95%confidence interval(CI):1.066-1.184,P<0.001).Serum ANGPTL8 and ANGPTL8+TyG index predicted MAFLD[area under the curve(AUC):0.832 and 0.886,respectively;both P<0.05].Compared with MAFL

关键词： Angiopoietin-like protein 8 Metabolic dysfunction-associated fatty liver disease Fibrosis-4 index Liver fibrosis

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Characteristics of Chinese Medicine Education Under British Education System in New Zealand

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Chinese Journal of Integrative Medicine 2019年第12期25卷 936-938页

作者： chang zhe ZHANG Chen-ming SUN Zi-xue WANG Zu-long CHEN Jian-she WANG zheng School of Foreign Language Henan University of Chinese MedicineZhengzhou(450046)China Second Clinical Medical School Henan University of Chinese MedicineZhengzhou(450002)China Department of Reproductive Medicine Henan Province Hospital of Traditional Chinese MedicineZhengzhou(450002)China Department of Ultrasound Henan Province Hospital of Traditional Chinese MedicineZhengzhou(450002)China

With the globalisation of Chinese medicine(CM), the local CM education institutions were established in many other countries outside of China. These CM education institutions have formed a new mode in CM education after integrating with local culture, law and national conditions. This article takes New Zealand CM education institutions as an example to discuss the characteristics of CM education under the British education system, aiming to provide ideas on CM education in China and other countries.

关键词： British education system Chinese medicine education education grading system moderation system

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