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Classification of anti-symmetric solutions to the fractional Lane-Emden system

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Science China Mathematics 2023年第4期66卷 723-744页

作者： congming li Ran Zhuo School of Mathematical Sciences and CMA-Shanghai Shanghai Jiao Tong UniversityShanghai 200240China School of Mathematics and Statistics Huanghuai UniversityZhumadian 463000China

We study the anti-symmetric solutions to the Lane-Emden type system involving fractional Laplacian(-△)^(s)(0liouville type theorem in the often-used defining space L_(2s).An interesting lower bound on the solutions is derived to estimate the lipschitz coefficient in the sub-linear *** the anti-symmetric property,one can naturally extend the defining space from L_(2s) to L_(2s+1).Surprisingly,with this extension,we show the existence of non-trivial *** is very different from the previous results of the Lane-Emden system.

关键词： Lane-Emden system fractional Laplacian maximum principle liouville type theorems existence

持续高温作用下花岗岩特征应力及声发射特征试验研究

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岩石力学与工程学报 2024年第7期43卷 1580-1592页

作者：赵奎李从明曾鹏熊良锋龚囱黄震江西理工大学资源与环境工程学院江西赣州341000 江西理工大学战略金属矿产资源低碳加工与利用江西省重点实验室江西赣州341000 江西理工大学稀有金属资源安全高效开采江西省重点实验室江西赣州341000

在核废料地质处置、地热资源开发等地下工程中,持续高温作用导致岩石强度和变形性能显著降低,易诱导工程灾害发生。因此探究持续高温作用下花岗岩特征应力及声发射特征具有重要意义。基于此,以350℃及950℃为目标温度,对不同高温持续时... 详细信息

在核废料地质处置、地热资源开发等地下工程中,持续高温作用导致岩石强度和变形性能显著降低,易诱导工程灾害发生。因此探究持续高温作用下花岗岩特征应力及声发射特征具有重要意义。基于此,以350℃及950℃为目标温度,对不同高温持续时间后花岗岩进行单轴压缩声发射试验,重点分析高温持续时间对特征应力点及其声发射特征影响规律。结果表明:(1)随着高温持续时间增加,花岗岩质量损失率、体积膨胀率、纵波衰减率呈指数型增大。(2) 350℃持续高温下,单轴抗压强度、弹性模量、峰值应变及特征应力随持续时间增加呈指数型增大;950℃持续高温下,单轴抗压强度、弹性模量及特征应力随持续时间增加呈指数型减小,峰值应变呈指数型增大。(3)特征应力受高温持续时间变化敏感度程度为:闭合应力>起裂应力>损伤应力>峰值应力。(4)随着高温持续时间增加,350℃下花岗岩特征应力处声发射主频减小、幅值增大,多重分形参数增加,小尺度破裂逐渐占主导;950℃下花岗岩特征应力处声发射主频增大、幅值减小,多重分形参数减小,大尺度破裂逐渐占主导。(5)高温引起的热致裂纹和孔隙变化主要在持续时间8 h前,超过8 h之后,高温持续时间对其影响程度显著降低。

关键词：岩石力学高温持续时间特征应力声发射多重分形 SEM

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多相催化加氢反应中H_(2)异裂解离的研究进展

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低碳化学与化工 2024年第1期49卷 1-11页

作者：姚正阳王晓月郭晓宏赵勇杰师文荣李聪明太原理工大学省部共建煤基能源清洁高效利用国家重点实验室山西太原030024

多相催化加氢反应是制备高附加值燃料及化学品的重要途径,而H_(2)异裂解离过程及其形成的氢化物(M—Hδ-)的化学性质与加氢反应活性和选择性密切相关。然而,由于多相催化剂表面结构复杂导致了H_(2)异裂解离过程及M—H^(δ-)化学性质的... 详细信息

多相催化加氢反应是制备高附加值燃料及化学品的重要途径,而H_(2)异裂解离过程及其形成的氢化物(M—Hδ-)的化学性质与加氢反应活性和选择性密切相关。然而,由于多相催化剂表面结构复杂导致了H_(2)异裂解离过程及M—H^(δ-)化学性质的多样性,为认识H_(2)异裂解离及M—H^(δ-)的化学性质对加氢反应机理的调控规律带来了巨大挑战。综述了H_(2)异裂解离的机理及M—H^(δ-)的化学性质,并介绍了常用于检测M—H^(δ-)的表征技术并分析了各自的优缺点。重点讨论了不同多相催化体系,如负载型金属催化剂、金属氧化物催化剂以及阴离子杂化金属催化剂中,H_(2)异裂解离与催化剂活性位点结构之间的内在关系及其对加氢反应性能的优化,并提出了调控H_(2)异裂解离的有效策略。最后,针对当前H_(2)异裂解离及M—H^(δ-)研究面临的主要挑战进行了总结,同时对未来发展方向进行了展望。

关键词：加氢反应 H_(2)异裂解离氢化物催化剂多相催化

Dynamic Analysis and Dimensional Synthesis of Easy-to-Protect Large-Load Robot for Extracting Fermented Grains

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Journal of Beijing Institute of Technology 2023年第4期32卷 529-550页

作者： Yubin Zhang Jinzhu Zhang congming li Xiaoyan Xiong Hongjie Du College of Mechanical and Vehicle Engineering Taiyuan University of TechnologyTaiyuan 030024China National Key Laboratory of Metal Forming Technology and Heavy Equipment Taiyuan University of TechnologyTaiyuan 030024China Engineering Research Center of Advanced Metal Composites Forming Technology and Equipment Ministry of EducationTaiyuan University of TechnologyTaiyuan 030024China

To improve the operation situation of difficulty and low efficiency in the extraction of fermented grains(FG),a high-load and large-workspace reclaiming robot for ceramic cylinder fermentation is designed,and a reclaiming effector is designed according to the operating ***,the kinematics and singularity of the mechanism are analyzed.A multi-domain polar coordinate search method is proposed to obtain the workspace and the volume of the ***,the dynamic modeling is completed and the example simulation is carried ***,the motion-force transmission index of the mechanism is *** based on the global transmissibility and the good-transmission workspace,the dimensional synthesis of the driving mechanism is completed by using the performance atlas-based ***,aiming at the regular workspace size,stiffness and loading capacity,the Pareto optimal solution set of the executive mechanism dimension is obtained by using the multi-objective particle swarm optimization(MOPSO)*** paper can provide a theoretical basis for the optimal design and control of FG reclaiming robot.

关键词： reclaiming robot configuration design performance index dynamic modeling multi-objective optimization

Bond behavior of the interface between concrete and basalt fiber reinforced polymer bar after freeze–thaw cycles

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Frontiers of Structural and Civil Engineering 2024年第4期18卷 630-641页

作者： li HONG Mingming li congming DU Shenjiang HUANG Binggen ZHAN Qijun YU Department of Structural Engineering Hefei University of TechnologyHefei 230009China Key Laboratory of Performance Evolution and Control for Engineering Structures Tongji UniversityShanghai 200092China Engineering Research Center of Low-carbon Technology and Equipment for Cement-based Materials(Ministry of Education) Hefei University of TechnologyHefei 230009China Hefei Cement Research&Design Institute Corporation Ltd. Hefei 230051China

The shear bond of interface between concrete and basalt fiber reinforced polymer(BFRP)bars during freeze–thaw(F–T)cycles is crucial for the application of BFRP bar-reinforced concrete structures in cold *** this study,48 groups of pull-out specimens were designed to test the shear bond of the BFRP-concrete interface subjected to F–T *** effects of concrete strength,diameter,and embedment length of BFRP rebar were investigated under numerous F–T *** results showed that a larger diameter or longer embedment length of BFRP rebar resulted in lower interfacial shear bond behavior,such as interfacial bond strength,initial stiffness,and energy absorption,after the interface goes through F–T ***,higher concrete strength and fewer F–T cycles were beneficial for enhancing the interfacial bond ***,a three-dimensional(3D)interfacial model based on the finite element method was developed,and the interfacial bond behavior of the specimens was analyzed ***,a degradation bond strength subjected to F–T cycles was predicted by a proposed mechanical *** predictions were fully consistent with the tested *** model demonstrated accuracy in describing the shear bond behavior of the interface under numerous F–T cycles.

关键词： F-T cycle interface shear bond strength bond stress−slip curves bond degradation

ERAS理念下人工髋关节置换术治疗股骨颈骨折合并尿毒症患者围手术期风险因素分析及处理

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皖南医学院学报 2024年第2期43卷 138-141页

作者：张银昌陈平波王超熊寿良李从明杨昕贺华正王强陶周善王雷皖南医学院第一附属医院弋矶山医院关节骨科安徽芜湖241001

目的:探讨加速康复(ERAS)理念下髋关节假体置换术在股骨颈骨折合并尿毒症患者中的疗效及安全性。方法:回顾分析2019年1月~2023年3月在弋矶山医院行人工髋关节置换术治疗股骨颈骨折合并尿毒症的18例患者,对患者进行围手术期的处理,记录... 详细信息

目的:探讨加速康复(ERAS)理念下髋关节假体置换术在股骨颈骨折合并尿毒症患者中的疗效及安全性。方法:回顾分析2019年1月~2023年3月在弋矶山医院行人工髋关节置换术治疗股骨颈骨折合并尿毒症的18例患者,对患者进行围手术期的处理,记录围手术期并发症情况,出院后门诊随访拍摄髋关节正位片并记录患者的疼痛视觉模拟评分法(VAS)评分、髋关节Harris评分及并发症等情况;同时选取20例同期行髋关节假体置换术的股骨颈骨折不合并尿毒症的患者作为对照组。结果:所有患者术后中位随访时间为16.1(3~36)月。合并尿毒症组男性占比较高、平均年龄更小、术前血红蛋白更低、围手术期输血率更高、住院时间更长(P0.05)。合并尿毒症组2例术后发生上消化道出血,1例出院后15 d发生关节假体脱位再次入院;两组患者末次随访时均未发生关节感染、假体松动、脱位、假体周围骨折等并发症。结论:通过围手术期的积极有效处理,ERAS理念下人工髋关节假体置换术治疗股骨颈骨折合并尿毒症患者效果满意。

关键词：股骨颈骨折尿毒症髋关节置换术围手术期透析并发症

CLASSIFICATION OF POSITIVE SOLUTIONS FOR NONliNEAR DIFFERENTIAL AND INTEGRAL SYSTEMS WITH CRITICAL EXPONENTS

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Acta Mathematica Scientia 2009年第4期29卷 949-960页

作者： Wenxiong Chen congming li Department of Mathematics Yeshiva University 500 W. 185th St. New York NY 10033 USA Department of Applied Mathematics Campus Box 526University of Colorado at Boulder Boulder CO 80309 USA

We classify all positive solutions for the following integral system：{ui（x）=∫Rn1/│x-y│^n-α fi（u（y））dy,x∈R^n,i=1,…,m,0〈α〈n,and u（x）=（u1（x）,u2（x）…,um（x））.Here fi（u）, 1 ≤ i ≤m, monotone nondecreasing are real-valued functions of homogeneous degree n＋α/n-α and are monotone nondecreasing with respect to all the independent variables U1, u2, ..., *** the special case n ≥ 3 and α = 2. we show that the above system is equivalent to thefollowing elliptic PDE system：This system is closely related to the stationary SchrSdinger system with critical exponents for Bose-Einstein condensate

关键词： integral and PDE systems positive solutions method of moving planes radial symmetry uniqueness

RADIAL SYMMETRY FOR SYSTEMS OF FRACTIONAL LAPLACIAN

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Acta Mathematica Scientia 2018年第5期38卷 1567-1582页

作者：李从明吴志刚 School of Mathematical Sciences Shanghai Jiao Tong University Shanghai 200240 China Department of Applied Mathematics University of Colorado Boulder USA Department of Applied Mathematics Donghua University Shanghai 201620 China

In this paper, we consider systems of fractional Laplacian equations in ]I^n with nonlinear terms satisfying some quite general structural conditions. These systems were categorized critical and subcritical cases. We show that there is no positive solution in the subcritical cases, and we classify all positive solutions ui in the critical cases by using a direct method of moving planes introduced in Chen-li-li [11] and some new maximum principles in li-Wu-Xu [27].

关键词： system of fractional Laplacian method of moving planes maximum principles with singular point Kelvin transform

AN EXTENSION OF THE HARDY-liTTLEWOOD-PóLYA INEQUAliTY

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Acta Mathematica Scientia 2011年第6期31卷 2285-2288页

作者： John Villavert Department of Applied Mathematics University of Colorado at Boulder

The Hardy-littlewood-PSlya （HLP） inequality [1] states that if a ∈ lp, b ∈ 1q and In this article, we prove the HLP inequality in the case where A = 1,p = q = 2 with a logarithm correction, as conjectured by Ding ... 详细信息

关键词： Hardy-littlewood-Polya inequality logarithm correction