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Non-limit passive soil pressure on rigid retaining walls

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International Journal of Mining Science and Technology 2017年第3期27卷 581-587页

作者： Dou Guotao Xia junwu YU Wenjie Yuan Fang Bai Weigang State Key Laboratory for Geomechanics and Deep Underground Engineering China University of Mining & Technology Xuzhou 221008 China Jiangsu Collaborative Innovation Center of Building Energy Saving and Construction Technology Xuzhou 221116 China Zhengzhou Zhongding Steel Structure Engineering Co. Ltd. Zhengzhou 450000 China

This paper aims to reveal the depth distribution law of non-limit passive soil pressure on rigid retaining wall that rotates about the top of the wall(rotation around the top(RT) model). Based on Coulomb theory, the disturbance degree theory, as well as the spring-element model, by setting the rotation angle of the wall as the disturbance parameter, we establish both a depth distribution function for sand and a nonlinear depth distribution calculation method for the non-limit passive soil pressure on a rigid retaining wall under the RT model, which is then compared with experiment. The results suggest that under the RT model: the non-limit soil pressure has a nonlinear distribution; the backfill disturbance degree and the lateral soil pressure increase with an increase in the wall rotation angle; and, the points where the resultant lateral soil pressure acts on the retaining wall are less than 2/3 of the height of the wall. The soil pressure predicted by the theoretical calculation put forward in this paper are quite similar to those obtained by the model experiment, which verifies the theoretical value, and the engineering guidance provided by the calculations are of significance.

关键词： RT model Rigid wall Non-limit passive soil pressure Spring element Genetic algorithm

Preliminary investigation of seismic damage to two steel space structures during the 2013 Lushan earthquake

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Earthquake Engineering and Engineering Vibration 2013年第3期12卷 497-500页

作者： Dai junwu Qu Zhe Zhang Chenxiao Weng Xuran Key Laboratory of Earthquake Engineering and Engineering Vibration Institute of Engineering MechanicsCEA

Severe damage to steel space structures is rarely reported when compared to other structural systems damaged during past major earthquakes around the world. Two gymnasiums of steel space structures in downtown Lushan County that were damaged during the 2013 M7.0 Lushan earthquake in China were investigated and the observations are summarized in this paper. Typical damage to these two steel space structures ranges from moderate to severe. Moderate damage includes global buckling and dislocation of bolted connections of truss members, and inelastic elongation of anchor bolts and sliding of pedestal plates of supports. Severe damage includes member fracture caused by local buckling, and fracture failure of anchor bolts and welds. The distribution of structural damage to these two structures is described in detail and future research opportunities are suggested.

关键词： Lushan earthquake steel space structure gymnasitun seismic damage member buckling fracture failure

企业国际化对创新绩效的影响机制——基于知识搜索的中介作用与母国市场竞争程度的调节作用

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科技管理研究 2024年第8期44卷 190-199页

作者：董俊武王研涂智雅广东外语外贸大学商学院广东广州510006

目前对企业国际化通过何种组织学习机制作用于创新绩效需要进一步明确,同时国际化影响创新绩效的外部情境条件需要进一步揭示。因此,基于组织学习理论与知识基础观,引入双元知识搜索(包括本地搜索和跨界搜索)作为中介变量、母国市场竞... 详细信息

目前对企业国际化通过何种组织学习机制作用于创新绩效需要进一步明确,同时国际化影响创新绩效的外部情境条件需要进一步揭示。因此,基于组织学习理论与知识基础观,引入双元知识搜索(包括本地搜索和跨界搜索)作为中介变量、母国市场竞争程度作为调节变量,构建“国际化程度—知识搜索—创新绩效”的理论逻辑,以2002—2020年中国A股的977家制造业上市公司为样本,实证检验企业国际化程度对创新绩效的影响,以及知识搜索与母国市场竞争程度在其中的中介作用和调节作用。结果表明:企业国际化程度对创新绩效呈倒“U”型影响,同时对本地搜索和跨界搜索都有显著正向影响;本地搜索对创新绩效有正向影响,但跨界搜索对创新绩效呈倒“U”型影响,当跨界搜索达到199.29时,企业继续扩展自己的知识边界会负向影响创新绩效,而知识搜索在国际化程度和创新绩效之间起有效中介作用;母国市场竞争程度在国际化程度和知识搜索之间起到正向调节作用。基于此,建议企业综合运用各种管理激励方法不断降低知识转移成本、促进知识搜索,同时根据市场竞争强度的变化调整知识搜索策略,及时进行知识创建和重组,进而提升创新绩效。

关键词：国际化程度企业创新绩效双元知识搜索市场竞争组织学习机制企业国际化

Synthesis of CdS multipods from cadmium xanthate in ethylenediamine solution

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Particuology 2015年第2期13卷 45-52页

作者： Qiaofeng Han Jin Zhao Lei Wu junwu Zhu Xin Wang Key Laboratory for Soft Chemistry and Functional Materials Ministry of EducationNanjing University of Science and Technology

CdS nanocrystals of various shapes were synthesized by using cadmium ethyldithiocarbonatio （xanthate） as a single precursor under solvothermal condition. The reaction temperature, cadmium concentration, and solvents determine the CdS morphology. Multipodal CdS structures of different fractions of all particles were obtained at temperatures ranging from 100 to 180 ℃ with the corresponding precursor concentrations in ethylenediamine （EDA） solution. This approach is different from that reported in the literature, where EDA is regarded as a solvent favorable to the formation ofCdS nanorods instead of pods. Uniform CdS multipods were prepared at 160 ℃ with 1.0 g of cadmium xanthate. The formation of CdS multipods in EDA solution may be attributed to a synergistic effect between the reaction temperature and Cd concentration, i.e., thermodynamically and kinetically controlled growth of the CdS wurtzite （WZ） and zinc blende （ZB） phases, as confirmed by the structural characterization of the component CdS crys- tals. EDA and xanthate ligands act as co-assisted capping agents in the growth of CdS multipods. When using N,N-dimethylformamide （DMF） and ethylene glycol （EG） as solvents, the CdS appears as triangular particles and flower-like microspheres assembled by polyhedrons, respectively.

关键词： Nanostructurecl materials Chemical synthesis Microstructure Transmission electron microscopy

Experimental and analytical studies on multiple tuned mass dampers for seismic protection of porcelain electrical equipment

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Earthquake Engineering and Engineering Vibration 2017年第4期16卷 803-813页

作者： Bai Wen Dai junwu Zhou Huimeng Yang Yongqiang Ning Xiaoqing Institute of Engineering Mechanics China Earthquake AdministrationHarbin 150080China Key Laboratory of Earthquake Engineering and Engineering Vibration of China Earthquake Administration Harbin 150080China

Porcelain electrical equipment （PEE）, such as current transformers, is critical to power supply systems, but its seismic performance during past earthquakes has not been satisfactory. This paper studies the seismic performance of two typical types of PEE and proposes a damping method for PEE based on multiple tuned mass dampers （MTMD）. An MTMD damping device involving three mass units, named a triple tuned mass damper （TTMD）, is designed and manufactured. Through shake table tests and finite element analysis, the dynamic characteristics of the PEE are studied and the effectiveness of the MTMD damping method is verified. The adverse influence of MTMD redundant mass to damping efficiency is studied and relevant equations are derived. MTMD robustness is verified through adjusting TTMD control frequencies. The damping effectiveness of TTMD, when the peak ground acceleration far exceeds the design value, is studied. Both shake table tests and finite element analysis indicate that MTMD is effective and robust in attenuating PEE seismic responses. TTMD remains effective when the PGA far exceeds the design value and when control deviations are considered.

关键词： current transformer damping porcelain electrical equipment finite element analysis multiple tuned massdampers shake table test

Performance Limit Evaluation Strategy for Automated Driving Systems

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Automotive Innovation 2022年第1期5卷 79-90页

作者： Feng Gao Jianwei Mu Xiangyu Han Yiheng Yang junwu Zhou State Key Laboratory of Vehicle NVH and Safety Technology ChongqingChina College of Mechanical and Vehicle Engineering Chongqing UniversityChongqingChina Passenger Vehicle Technical Center Dongfeng Liuzhou Motor Co.LtdLiuzhouChina

Efficient detection of performance limits is critical to autonomous *** autonomous driving is difficult to be realized under complicated scenarios,an improved genetic algorithm-based evolution test is proposed to accelerate the evaluation of performance *** conducts crossover operation at all positions and mutation several times to make the high-quality chromosome exist in candidate offspring *** the normal offspring is selected statistically based on the scenario com-plexity,which is designed to measure the difficulty of realizing autonomous driving through the Analytic Hierarchy *** benefits of modified cross/mutation operators on the improvement of scenario complexity are analyzed ***,the effectiveness of improved genetic algorithm-based evolution test is validated after being applied to evaluate the collision avoidance performance of an automatic parallel parking system.

关键词： Autonomous driving Test and evaluation Evolution test Genetic algorithm

Well-dispersed ultrafine nitrogen-doped TiO_2 with polyvinylpyrrolidone(PVP) acted as N-source and stabilizer for water splitting

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Journal of Energy Chemistry 2016年第1期25卷 1-9页

作者： Tianyu Liu Wei Chen Xiaoheng Liu junwu Zhu Lude Lu Key Laboratory for Soft Chemistry and Functional Materials Nanjing University of Science and Technology Ministry of Education

In this paper, ultrafine nitrogen-doped TiO2 photocatalyst with enhanced photocatalytic water-splitting properties was successfully fabricated via a solvothermal method. Herein, polyvinylpyrrolidone（PVP） was used as both nitrogen source and stabilizer. The enhancement in water-splitting process can be attributed to the doping of element nitrogen, which could supply an intermediate energy level and promote the separation of photo-excited holes and electrons. Moreover, this paper provides a new application of high-molecular polymer to synthesize solar-driven water-splitting photocatalysts.

关键词： N-doped TiO2 Polyvinylpyrrolidone(PVP) Solar-light driven Water splitting

Finite element analysis of an all-steel buckling-restrained brace

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Earthquake Engineering and Engineering Vibration 2022年第4期21卷 1119-1135页

作者： Jiang Tao Dai junwu Yang Yongqiang Bai Wen Pang Hui Liu Rongheng Key Laboratory of Earthquake Engineering and Engineering Vibration Institute of Engineering MechanicsChinaEarthquake AdministrationHarbin 150080China Key Laboratory of Earthquake Disaster Mitigation Ministry of Emergency ManagementHarbin 150080China

Typical all-steel buckling-restrained braces(BRBs)usually exhibit obvious local buckling,which is attributed to the lack of longitudinal restraint to the rectangle core *** address this issue,all-steel BRBs are proposed,in which two T-shaped steel plates are adopted as the minor restraint elements to restrain the core plate instead of infilled concrete or *** order to investigate the factors that characterize the hysterical responses of this device,different finite element(FE)models are developed for the specific *** FE models are developed based on nonlinear finite element software,which incorporate continuum(shell or brick)elements,large displacement,and deformation *** these FE models,two different steel constitutive models are adopted to precisely reproduce the cyclic response of the BRB ***,comparisons between the numerical and experimental results are conducted to validate the effectiveness and accuracy of the robust FE *** agreements between experimental observations and numerical predictions demonstrate that the FE method could be utilized for in depth parametric ***,BRBs with detailed configurations can provide excellent hysteretic behavior and seismic performance through the optimal design process.

关键词： steel BRB T-shaped steel finite element model optimal design hysteretic behavior

改良血管套接法对断指再植患者断指血运及成活情况的影响

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中国医学工程 2024年第9期32卷 85-88页

作者：龚俊武闫纪涛刘东博漯河市第二人民医院显微外科河南漯河462000

目的分析改良血管套接法对断指再植患者断指血运及成活情况的影响。方法本次研究筛选漯河市第二人民医院2019年1月至2023年4月收治的断指再植患者作为研究对象,依照纳入、排除标准进行选例,共选取80例,将其纳入研究后回顾性分析相关临... 详细信息

目的分析改良血管套接法对断指再植患者断指血运及成活情况的影响。方法本次研究筛选漯河市第二人民医院2019年1月至2023年4月收治的断指再植患者作为研究对象,依照纳入、排除标准进行选例,共选取80例,将其纳入研究后回顾性分析相关临床资料,依据不同血管吻合方式进行组别的分配(血管断端吻合法组、改良血管套接法组),分组例数相等(各40例)。所有患者均接受断指再植手术治疗,但前者采用血管断端吻合法、后者采用改良血管套接法进行血管吻合。均观察至出院,随访3个月。对比两组相关指标。结果改良血管套接法组术后3 d的毛细血管充盈时间短于血管断端吻合法组,经皮氧分压高于血管断端吻合法组,断指微循环检测值低于血管断端吻合法组,血管断端吻合法组术后7 d的断指成活率为70.00%(28/40),改良血管套接法组为90.00%(36/40),改良血管套接法组更高(χ2=5.000,P<0.05);两组术后1个月、术后3个月的Carroll双上肢功能评定(UEFT)评分均升高,改良血管套接法组更高;术后3个月两组世界卫生组织生存质量测定量表(WHOQOL-100)各项生活质量评分相比于治疗前均升高,而改良血管套接法组均较血管断端吻合法组更高;两组随访期间并发症总发生率比较,改良血管套接法组低于血管断端吻合法组(P<0.05)。结论改良血管套接法可显著促进断指再植患者断指血运情况的恢复,改善其手指运动功能,提高断指再植成活率及生活质量,减少并发症的发生,有着较高的安全性。

关键词：断指再植改良血管套接法断指血运情况断指再植成活率