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碳纤维表面性质分析及其对复合材料界面性能的影响

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航空材料学报 2010年第3期30卷 43-47页

作者：石峰晖代志双张宝艳北京航空材料研究院北京100095 北京航空航天大学北京100191

研究了T300-3K和T300-6K碳纤维的表面物理和化学特性,并对其与环氧树脂复合材料体系的界面性能进行了测试与分析。结果表明T300-6K碳纤维表面的O/C比和活性碳原子比例均高于T300-3K碳纤维。T300-6K碳纤维表面沟槽深度、宽度和长度均大于... 详细信息

研究了T300-3K和T300-6K碳纤维的表面物理和化学特性,并对其与环氧树脂复合材料体系的界面性能进行了测试与分析。结果表明T300-6K碳纤维表面的O/C比和活性碳原子比例均高于T300-3K碳纤维。T300-6K碳纤维表面沟槽深度、宽度和长度均大于T300-3K碳纤维但表面粗糙度较小。T300-6K碳纤维环氧树脂体系的界面剪切强度与相应的T300-3K体系基本相当。

关键词：碳纤维复合材料界面

全自动三维超声右心室定量软件评价系统性红斑狼疮患者右心室收缩功能

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实用医学杂志 2023年第5期39卷 636-641页

作者：代爽冯艳红锦州医科大学附属第一医院超声科辽宁锦州121001

目的应用全自动三维超声右心室定量软件(3DAutoRV)技术在系统性红斑狼疮(SLE)患者的右心室收缩功能评价中的应用价值。方法选取2020年10月至2022年6月在锦州医科大学附属第一医院临床诊断为SLE患者,对入选的87例患者进行分组(A组:40例... 详细信息

目的应用全自动三维超声右心室定量软件(3DAutoRV)技术在系统性红斑狼疮(SLE)患者的右心室收缩功能评价中的应用价值。方法选取2020年10月至2022年6月在锦州医科大学附属第一医院临床诊断为SLE患者,对入选的87例患者进行分组(A组:40例,三尖瓣反流峰值低速率≤2.8 m/s,无其他肺动脉高压超声心动图表现;B组:27例,三尖瓣反流峰值速率≤2.8 m/s,有其他肺动脉高压超声心动图表现或三尖瓣峰值速率2.9~3.4 m/s,无其他肺动脉高压超声心动图表现;C组:20例,三尖瓣反流峰值速率> 3.4 m/s),另选健康对照组29例(D组)。记录所有研究对象年龄、性别、心率、体质指数(BMI)、血压等,常规超声获得三尖瓣环收缩期峰值速度(S′)、右心室舒张末期横径(RVED)、右心室前壁厚度(RVAW)、三尖瓣环位移(TAPSE)、右心室面积变化率(RVFAC)。3DAutoRV软件获得三尖瓣环位移(TAPSE)、右心室面积变化率(RVFAC)、右心室舒张末期容积(RVEDV)、右心室收缩末期容积(RVESV)、右心室每搏量(RVSV)及右心室射血分数(RVEF)、右室基底段横径(RVD1)、右室中间段横径(RVD2)、右室长径(RVD3)、右心室游离壁纵向应变(FWLS)、右心室室间隔纵向应变(SLS)。结果 (1)对照组与SLE患者相比,年龄、收缩压、舒张压及BMI差异均无统计学意义(P> 0.05),而C组与其他组相比心率明显增快,差异有统计学意义(P 0.05)。与B组相比,C组TAPSE、FAC、S′、SLS、FWLS、RVEF、RVSV减低,EDV、ESV均增加(P <0.05)。(3)FWLS预测SLE-PAH的最佳截断值为-23.32(AUC=0.90,P <0.001)。(4)一致性检验与重复性分析显示RVEF和FWLS具有良好的重复性。结论 3DAutoRV软件可以为评估SLE患者右心室收缩功能提供依据。

关键词：肺动脉高压右心室功能三维超声右心室定量系统性红斑狼疮

Exploration of Strong Metal-Support Interaction in Heterogeneous Catalysts by in situ Transmission Electron Microscopy

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Chinese Journal of Chemistry 2024年第9期42卷 1004-1008页

作者： Yongjun Jiang Sheng dai Key Laboratoryfor Advanced Materials and Feringa Nobel Prize Scientist Joint Research Center Institute of Fine ChemicalsSchool of Chemistry&Molecular EngineeringEast China Universityof Science and TechnologyShanghai 200237China

The phenomenon of strong metal-support interaction(SMSI)observed in supported metal catalysts,usually accompanied by the formation of the encapsulation layer on metal nanoparticles,has attracted extensive research attention due to its significance in heterogeneous ***,great progress has been made in recent years in investigating SMSI by in situ transmission electron microscopy(TEM),along with an enhanced comprehension of the underlying mechanisms governing SMSI *** emerging topic summarizes recent progress utilizing in situ TEM to study the interaction between metal and support and the relationship between the structure and performance of the supported catalyst under reaction conditions.A brief perspective about the use of in situ TEM for further study of SMSI is also presented,showing prospects in this field that will stimulate further upsurging research in promoting the catalytic efficiency of supported catalysts.

关键词： Heterogeneous catalysis In situ TEM Strong metal-support interaction Structure changes Interfaces Structural evolution

SEMI-PROXIMAL POINT METHOD FOR NONSMOOTH CONVEX-CONCAVE MINIMAX OPTIMIZATION

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Journal of Computational Mathematics 2024年第3期42卷 617-637页

作者： Yuhong dai Jiani Wang Liwei Zhang LSEC ICMSECAMSSChinese Academy of SciencesBeijing 100190China School of Mathematical SciencesUniversity of Chinese Academy of SciencesBeijing 100049China Academy of Mathematics and Systems Science Chinese Academy of SciencesBeijing 100190China School of Mathematical Sciences Dalian University of TechnologyDalian 116024China

Minimax optimization problems are an important class of optimization problems arising from modern machine learning and traditional research *** there have been many numerical algorithms for solving smooth convex-concave minimax problems,numerical algorithms for nonsmooth convex-concave minimax problems are *** paper aims to develop an efficient numerical algorithm for a structured nonsmooth convex-concave minimax problem.A semi-proximal point method(SPP)is proposed,in which a quadratic convex-concave function is adopted for approximating the smooth part of the objective function and semi-proximal terms are added in each *** construction enables the subproblems at each iteration are solvable and even easily solved when the semiproximal terms are cleverly *** prove the global convergence of our algorithm under mild assumptions,without requiring strong convexity-concavity *** the locally metrical subregularity of the solution mapping,we prove that our algorithm has the linear rate of *** numerical results are reported to verify the efficiency of our algorithm.

关键词： Minimax optimization Convexity-concavity Global convergence Rate of con-vergence Locally metrical subregularity

Potential effects of automated driving on vehicle travel demand: A comparison of three case cities

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Journal of Traffic and Transportation Engineering(English Edition) 2024年第2期11卷 348-361页

作者： Jingchen dai Ruimin Li Zhiyong Liu School of Civil Engineering Tsinghua UniversityBeijing 100084China Hang Lung Center for Real Estate Tsinghua UniversityBeijing 100084China School of Traffic and Transportation Beijing Jiaotong UniversityBeijing 100044China

Automated vehicles(AVs)hold the potential to reduce road accidents,mitigate traffic congestion,and improve travel ***,the possible countervailing impacts from the changes in underserved populations’vehicle travel demand tend to be *** determine the vehicle travel demand changes that resulted from underserved populations aged between 6 and 80,this paper explores the latent effect of AVs on vehicle kilometers traveled(VKT)in a fully AV environment using person trip survey data from the cities of Sanya,Shijiazhuang,and Shenzhen in *** paper uses the natural decline hypothesis of travel demand and proposes a regression model to investigate the difference among the cities’latent vehicle travel *** show that the average VKT of the overall population in Sanya,Shijiazhuang,and Shenzhen increased by 33.4%,47.0%,and46.8%,*** analysis of the regression model confirms that the current travel behavior of individuals can affect the degree of increase in their average *** AVs into public transport,increasing the acceptance of automated shared mobility options,transforming road space use type,and prototyping AV designs with various features and needs are potential methods to cope with the countervailing *** total VKT of the overall population increased by approximately 10%-25%depending on the *** conclusions of this paper provide informative insights into the evaluation of VKT for underserved populations and contribute to the deployment of AVs to address equity and inclusion issues.

关键词： Automated vehicles Vehicle kilometers traveled Aging population Travel behavior Natural decline hypothesis

Study on the optimal incident proton energy of ^(7)Li(p,n)^(7)Be neutron source for boron neutron capture therapy

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Nuclear Science and Techniques 2024年第3期35卷 170-180页

作者： Yi-Nan Zhu Zuo-Kang Lin Hai-Yan Yu Ye dai Zhi-Min dai Xiao-Han Yu Shanghai Institute of Applied Physics Chinese Academy of SciencesShanghai 201800China University of Chinese Academy of Science Beijing 100049China

Boron neutron capture therapy(BNCT)is recognized as a precise binary targeted radiotherapy technique that effectively eliminates tumors through the^(10)B(n,α)^(7)Li nuclear *** various neutron sources,accelerator-based sources have emerged as particularly promising for BNCT ***^(7)Li(p,n)^(7)Be reaction is highly regarded as a potential neutron source for BNCT,owing to its low threshold energy for the reaction,significant neutron yield,appropriate average neutron energy,and additional *** study utilized Monte Carlo simulations to model the physical interactions within a lithium target subjected to proton bombardment,including neutron moderation by an MgF_(2)moderator and subsequent BNCT dose analysis using a Snyder head *** study focused on calculating the yields of epithermal neutrons for various incident proton energies,finding an optimal energy at 2.7 ***,the Snyder head phantom was employed in dose simulations to validate the effectiveness of this specific incident energy when utilizing a^(7)Li(p,n)^(7)Be neutron source for BNCT purposes.

关键词： Boron neutron capture therapy ^(7)Li(p,n)7Be neutron source Incident proton energy Monte Carlo simulation

Rockburst criterion and evaluation method for potential rockburst pit depth considering excavation damage effect

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第5期16卷 1649-1666页

作者： Jinhao dai Fengqiang Gong Lei Xu Engineering Research Center of Safety and Protection of Explosion & Impact of Ministry of Education (ERCSPEIME) Southeast UniversityNanjing211189China School of Civil Engineering Southeast UniversityNanjing211189China

Excavation-induced disturbances in deep tunnels will lead to deterioration of rock properties and formation of excavation damaged zone(EDZ).This excavation damage effect may affect the potential rockburst pit *** two diversion tunnels of Jinping II hydropower station for example,the relationship between rockburst pit depth and excavation damage effect is first *** results indicate that the rockburst pit depth in tunnels with severe damage to rock masses is relatively ***,the excavation-induced damage effect is characterized by disturbance factor D based on the Hoek-Brown criterion and wave velocity *** is found that the EDZ could be further divided into a high-damage zone(HDZ)with D=1 and weak-damage zone(WDZ),and D decays from one to zero *** this,a quantitative evaluation method for potential rockburst pit depth is established by presenting a three-element rockburst criterion considering rock strength,geostress and disturbance *** evaluation results obtained by this method match well with actual *** addition,the weakening of rock mass strength promotes the formation and expansion of potential rockburst *** potential rockburst pit depth is positively correlated with HDZ and WDZ depths,and the HDZ depth has a significant contribution to the potential rockburst pit depth.

关键词： Deep tunnel Rockburst Rockburst pit Excavation damage effect Hoek-Brown criterion

The Influence of the Sun and Moon on the Observation of Very High Energy Gamma-ray Sources Using EAS Arrays

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Research in Astronomy and Astrophysics 2024年第6期24卷 245-252页

作者： Tao Wen Songzhan Chen Benzhong dai School of Physics and Astronomy Yunnan UniversityKunming 650091China Key Laboratory of Particle Astrophysics Institute of High Energy PhysicsChinese Academy of SciencesBeijing 100049China Tianfu Cosmic Ray Research Center Chengdu 610000China

With great advance of ground-based extensive air shower arrays,such as LHAASO and HAWC,many very high energy(VHE)gamma-ray sources have been discovered and are being monitored regardless of the day and the ***,the Sun and Moon would have some impacts on the observation of gamma-ray sources,which have not been taken into account in previous *** this paper,the influence of the Sun and Moon on the observation of very high energy gamma-ray sources when they are near the line of sight of the Sun or Moon is *** tracks of all the known VHE sources are scanned and several VHE sources are found to be very close to the line of sight of the Sun or Moon during some *** absorption of very high energy gamma rays by sunlight is estimated with detailed method and some useful conclusions are *** main influence is the block of the Sun and Moon on gamma rays and the shadow on the cosmic ray *** influence is investigated considering the detector angular resolution and some strategies on data analysis are proposed to avoid the underestimation of the gamma-ray emission.

关键词： astroparticle physics Sun:general methods:observational Sun:UV radiation

The Early Cenozoic Uplift of Qilian Mountain: detailed description by magnetic susceptibility and grained-size

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The Early Cenozoic Uplift of Qilian Mountain: detailed descr...