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拱桥断索冲击响应模型试验与有限元分析

中国公路学报 2024年第5期37卷 138-150页

作者：黄永辉霍建宏傅继阳刘爱荣饶瑞广州大学风工程与工程振动研究中心广东广州510006

为研究吊杆断裂对拱桥力学性能的影响,以广州海心桥为研究对象,设计并制作了几何相似比为1∶40的缩尺模型,采用缓慢卸载索力和突然断索2种方式开展吊杆断裂试验,讨论了2种吊杆失效模式对剩余构件静、动力响应的变化规律。然后采用ANSYS... 详细信息

为研究吊杆断裂对拱桥力学性能的影响,以广州海心桥为研究对象,设计并制作了几何相似比为1∶40的缩尺模型,采用缓慢卸载索力和突然断索2种方式开展吊杆断裂试验,讨论了2种吊杆失效模式对剩余构件静、动力响应的变化规律。然后采用ANSYS软件建立了有限元模型,通过瞬态分析方法对断索过程和结构响应进行了数值模拟。试验结果表明:位于L/4拱肋处的中吊杆失效后对邻近吊杆的冲击效应最为显著;吊杆索力的重分配比例随着距离断索区域的增加而减小;对于失效吊杆左右距离相同的邻近吊杆,索体长度越短的吊杆其索力分配比例越大。拱桥跨中和L/4附近吊杆断裂后的索力可近似全部由剩余吊杆承担;靠近拱脚处吊杆失效后,其一部分索力按照重分配比例由剩余吊杆分担,另一部分通过拱梁结合段直接传递到拱肋。不同典型位置处吊杆骤断后,引起邻近2根吊杆的索力动力放大系数在1.3~1.8范围内。结果可为吊杆断裂后拱桥的结构安全评估提供参考。

关键词：桥梁工程吊杆断裂模型试验拱桥有限元分析动力放大系数

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单向应力作用下地下采空区顶板破坏规律特征

有色金属工程 2024年第1期14卷 130-137页

作者：霍健张泉陶治臣陈晓青辽宁科技大学矿业工程学院辽宁鞍山114051 鞍钢基石矿业有限公司辽宁鞍山114051

针对单向应力作用于地下采空区顶板的破坏规律特性问题,基于弹性薄板理论和压力拱理论,利用单轴压力试验机对顶板模型进行了试验,并探究了不同荷载条件下顶板模型的受压过程和变形特性。结果表明:顶板的破坏过程与峰值应力是否超过疲劳... 详细信息

针对单向应力作用于地下采空区顶板的破坏规律特性问题,基于弹性薄板理论和压力拱理论,利用单轴压力试验机对顶板模型进行了试验,并探究了不同荷载条件下顶板模型的受压过程和变形特性。结果表明:顶板的破坏过程与峰值应力是否超过疲劳强度密切相关,超过疲劳强度时会出现加速破坏阶段;顶板的变形过程可以分为三个阶段,分别对应于不同的应力和应变变化规律;顶板的失稳破坏位置与荷载条件有关,周期荷载条件下更容易导致整体垮落塌陷;侧帮支撑作用对顶板的承载能力和稳定性有正面影响,但也会增加应力集中和变形。研究结果对于理解顶板在不同荷载条件下的力学行为和提高顶板的安全性具有重要意义。

关键词：岩石力学地下空区弹性薄板压力拱应力应变

Study on Enzymatic Hydrolysis of Gadus morrhua Skin Collagen and Molecular Weight Distribution of Hydrolysates

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Agricultural Sciences in China 2009年第6期8卷 723-729页

作者： huo jian-xin ZHAO Zheng Jinzhong University Jinzhong 030600 P.R. China College of Food Engineering ＆ Biotechnology Tianjin University of Science ＆ Technology Tianjin 300457 P.R.China

Process parameters on enzymatic hydrolysis and molecular weight （MW） distribution of collagen hydrolysates from Gadus morrhua skin were investigated. The optimal process parameters were obtained by the single-factor and orthogonal experiments. The molecular weight distribution of hydrolysates was determined using both Sephadex G25 partition and high speed liquid chromatography electricity spray mass spectrum （HPLC-ESI-MS）. Collagen hydrolysates were first gained by an alkaline protease ＂alcalase＂ for 3 h at temperature （50~C）, pH （10.0）, substrate concentration （75 g L-~）, and E/S （3%）. The molecular weight distribution of collagen hydrolysates ranged from 300 to 1 500 Da, and most of peptides were under 1 200 Da. Sephadex G25 partition and HPLC-ESI-MS should be successfully employed to determine the molecular weight distribution of collagen hydrolysates.

关键词： collagen hydrolysates Gadus morrhua molecular weight distribution alkaline protease

On Rough Marcinkiewicz Integrals along Surfaces

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Acta Mathematica Sinica,English Series 2010年第4期26卷 717-730页

作者： huo Xiong WU jian Kai XU School of Mathematical Sciences Xiamen University Xiamen 361005 P. R. China

In this paper, the authors establish the LP-mapping properties of certain classes of Marcinkiewicz integral operators along surfaces with rough kernels. The results in this paper essentially extend as well as improve ... 详细信息

关键词： Marcinkiewicz integrals surfaces maximal operator Hardy space rough kernel

Evaluation of individualized treatment of nonproliferative diabetic retinopathy:a multicenter,randomized,parallel-controlled study

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Journal of Traditional Chinese Medicine 2022年第1期42卷 90-95页

作者： huo jian DUAN Junguo LIU Lisha ZHANG Fuwen ZHU Keyu SUI Jiaqing jian Wenyuan Department of Ophthalmology Chengdu Women's and Children's Central HospitalSchool of MedicineUniversity of Electronic Science and Technology of ChinaChengdu 611731China College of Ophthalmology Chengdu University of Traditional Chinese MedicineChengdu 610075China

OBJECTIVE:To evaluate the differences in the efficacy of stationary treatment and individualized treatment for patients with nonproliferative diabetic retinopathy(NPDR).METHODS:This study was a randomized,controlled,multicenter clinical *** with NPDR were randomized into the stationary treatment group or the individualized treatment *** stationary treatment group was given the basic treatment and Qiming granules,and the individualized treatment group was given the basic treatment,Qiming granules,and individualized Chinese herbal medicines over a 12-week *** individualized therapeutic formula was also changed over time to adjust to the changes in the clinical presentation of the *** conducted observations of fundus retinal exudation and hemorrhage,visual acuity,Traditional Chinese Medicine symptom scores and other ***:A total of 140 participants with NPDR were randomized into the stationary treatment group or the individualized treatment group,and 132 participants completed this *** the 12-week treatment,significant improvements in both primary and secondary outcomes were observed in the stationary and individualized treatment *** remarkable difference in the primary outcomes between the two groups was ***,there was a significant difference in the Traditional Chinese Medicine symptom scores(18±7 vs 15±6;P<0.05).There were no severe adverse ***:Compared with stationary treatment,individualized treatment is more effective at relieving the Traditional Chinese Medicine symptoms and improving vision and fundus lesions at 12 weeks post treatment.

关键词： diabetic retinopathy individualized treatment randomized controlled trial Qiming granules

两机一洞尾水调压室阻抗损失系数模型试验研究

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水电能源科学 2024年第2期42卷 161-165页

作者：周嘉伟胡定辉刘火箭刘志雄长江科学院水力学研究所湖北武汉430014 长江勘测规划设计研究有限责任公司湖北武汉430014

水电站引水发电系统中调压室的阻抗损失系数是影响机组过渡过程计算结果的重要因素,目前阻抗损失系数一般在行业规范推荐的范围内进行取值,往往与试验值有所偏差,不利于调压室体型的优化设计。通过采用大比尺的调压室水工模型,对两机一... 详细信息

水电站引水发电系统中调压室的阻抗损失系数是影响机组过渡过程计算结果的重要因素,目前阻抗损失系数一般在行业规范推荐的范围内进行取值,往往与试验值有所偏差,不利于调压室体型的优化设计。通过采用大比尺的调压室水工模型,对两机一洞型式的水电站阻抗式尾水调压室进行大流量条件下的水力学试验,研究不同水流流态和分流比对调压室阻抗损失系数的影响,分析控制工况下调压室的流入和流出阻抗损失系数,给出了调压室阻抗损失系数与分流比的拟合公式和关系曲线。研究结果填补了两机一洞型式的水电站尾水调压室阻抗损失系数试验的空白,可为此类调压室的水力计算分析提供依据。

关键词：两机一洞尾水调压室模型试验阻抗损失系数分流比

3D打印导板辅助穿刺引流术治疗脑出血临床观察

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中国实用神经疾病杂志 2024年第2期27卷 149-153页

作者：霍健王礼东王旭范家权六安市中医院安徽六安237000

目的探讨3D打印导板辅助穿刺引流术治疗20 mL左右脑出血患者的临床疗效。方法将105例脑出血患者随机分为对照组和观察组,实施常规保守治疗的53例分为对照组,实施3D打印导板辅助穿刺引流术治疗的53例分为观察组。比较2组血肿清除率、神... 详细信息

目的探讨3D打印导板辅助穿刺引流术治疗20 mL左右脑出血患者的临床疗效。方法将105例脑出血患者随机分为对照组和观察组,实施常规保守治疗的53例分为对照组,实施3D打印导板辅助穿刺引流术治疗的53例分为观察组。比较2组血肿清除率、神经功能[美国国立卫生研究院卒中量表(NIHSS)评分]、认知功能[简易智力状态检查量表(MMSE)评分]及肢体功能[Fugl-Meyer运动功能量表(FMA)评分],并记录2组治疗期间并发症情况。结果观察组治疗后1 d、3 d及10 d的血肿清除率分别为(78.45±5.06)%、(80.73±5.29)%及(82.68±5.17)%,高于对照组的(32.16±4.12)%、(36.47±4.38)%、(42.67±4.78)%(P<0.05),观察组住院时间短于对照组(P<0.05)。治疗后,观察组NIHSS评分为(13.17±1.82)分,显著低于对照组的(18.64±2.71)分(P<0.05),MMSE评分和FMA总评分显著高于对照组[(28.67±1.24)分比(26.25±2.62)分,(77.03±10.13)分比(65.50±8.89)分](P<0.05)。观察组总并发症发生率为5.76%,低于对照组的18.87%(P<0.05)。结论相对于保守治疗,3D打印导板辅助穿刺引流术治疗20 mL左右脑出血患者疗效确切,可显著提升患者血脂清除率,改善患者认知功能和肢体功能,且能降低脑出血总并发症发生率。

关键词：脑出血 3D打印导板穿刺引流术认知功能肢体功能并发症

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三相交错并联直流变换器母排低电感设计

电力电子技术 2024年第8期58卷 116-120页

作者：陈卓贾利民程鹏霍箭华北电力大学能源电力创新研究院北京102206 北京交通大学先进轨道交通自主运行全国重点实验室北京100044 北京能高自动化技术股份有限公司北京100044

由于开关器件频率的提升和电压等级的提高,功率回路中的杂散电感引起的冲击电压影响越来越受到关注。为解决在高频器件下因母排杂散电感引起的冲击电压过高的现象,将以往研究中的解析法建模和部分元等效两种方法结合起来建立能同时反映... 详细信息

由于开关器件频率的提升和电压等级的提高,功率回路中的杂散电感引起的冲击电压影响越来越受到关注。为解决在高频器件下因母排杂散电感引起的冲击电压过高的现象,将以往研究中的解析法建模和部分元等效两种方法结合起来建立能同时反映结构参数作用机理并反映各部分电感对冲击电压影响的综合电感模型。利用模型按照叠层方式设计、基础尺寸设计和器件布局设计3步设计了一款用于三相交错并联直流变换器的叠层母排。对于其中有着复杂影响效果的结构参数,将数学模型代入双层规划算法,进行了参数寻优。最终设计了一款低杂散电感、低冲击电压母排,并通过双脉冲实验验证了设计的有效性和模型的准确性。

关键词：杂散电感变换器叠层母排

Synergistic silver-mediated and palladium-catalyzed nondirected olefination of aryl C–H bond: quick access to multi-substituted aryl olefins

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Science China Chemistry 2024年第3期67卷 882-889页

作者： jian Yao Lili Shao Xiaohong huo Xiaoming Wang Shanghai Key Laboratory for Molecular Engineering of Chiral Drugs Frontiers Science Center for Transformative MoleculesSchool of Chemistry and Chemical EngineeringShanghai Jiao Tong UniversityShanghai 200240China State Key Laboratory of Organometallic Chemistry Center for Excellence in Molecular SynthesisShanghai Institute of Organic ChemistryChinese Academy of SciencesShanghai 20032China School of Chemistry and Materials Science Hangzhou Institute for Advanced StudyUniversity of Chinese Academy of SciencesHangzhou 310024China

Transition metal-catalyzed olefination of aryl C-H bond is a powerful tool for the synthesis of alkenes. While the Pd-catalyzed oxidative C-H olefination of arenes, also known as Fujiwara-Moritani reaction, has been established as one of the most efficient methods, the substrates are largely limited to terminal olefins with electron-withdrawing group(s). Herein, we report a synergistic silver-mediated and palladium-catalyzed non-directed C-H olefination of arenes with vinyl(pseudo)halides, which offers a complementary strategy to the typical Fujiwara-Moritani reaction. The reactions proceeded well for a variety of halogenated arenes, heteroarenes, and olefin substrates, providing an efficient access to various multi-substituted aryl olefins, including trisubstituted/tetrasubstituted olefins and several complex olefins derived from medicines or natural products. Mechanistic studies indicated a bimetallic Pd/Ag cooperation is operative in the catalysis, i.e., the reaction is initiated by aryl C-H bond cleavage via ligation with phosphine/Ag species, followed by transferring of the aryl moiety to a vinyl palladium intermediate,which is in turn formed by oxidative addition of vinyl(pseudo)halide to a Pd complex. This method enables the synthesis of a wide range of challenging multi-substituted vinyl products from simple arenes(directing-group free) in a streamlined and controllable fashion.

关键词： direct C–H olefination multi-substituted aryl alkenes bimetallic Pd/Ag cooperation C–H functionalization