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Temporary Bearing Method in Construction of Continuous Beam Bridge Erected as Simply-Supported Beam 被引量:1
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作者 Mehadi Hassan Rabby Zhipei Guo Miaoqiang Huang 《Open Journal of Civil Engineering》 2018年第4期473-477,共5页
The present practice in Bangladesh for erection of girders is placing the girder directly on the bearing pad and joining the adjacent two spans in deck slab level by adopting expansion joints, as the bridges are prese... The present practice in Bangladesh for erection of girders is placing the girder directly on the bearing pad and joining the adjacent two spans in deck slab level by adopting expansion joints, as the bridges are presently designed as simply-supported beam bridge. The main disadvantage of this type of bridges is that, the seismic resistance is weak, and under the external force beyond the design range, the bridges are more likely to fall in danger because of failure in girders. Also they have expansion joints for each span, which affects the comfort of driving and the overall integrity of the bridge deck is poor [1]. Therefore, design and construction of the bridges have been revised to establish continuity between girders of two adjacent spans and transform the bridge as simply supported continuous beam bridge [2]. Temporary bearing (sandbox) method is proposed in this paper to solve the system transformation of continuous beam bridges. Design of the temporary bearing is very simple and can be manufactured at site. This method has been proved in construction of Arial Kha Bridge and can be applied for other similar bridges in Bangladesh. 展开更多
关键词 TEMPORARY Bearing simply supported SPAN simply supported continuous GIRDER Expansion Joints CAST-IN-SITU GIRDER Joint Section
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An Approach to Continuous Approximation of Pareto Front Using Geometric Support Vector Regression for Multi-objective Optimization of Fermentation Process 被引量:1
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作者 吴佳欢 王建林 +1 位作者 于涛 赵利强 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2014年第10期1131-1140,共10页
The approaches to discrete approximation of Pareto front using multi-objective evolutionary algorithms have the problems of heavy computation burden, long running time and missing Pareto optimal points. In order to ov... The approaches to discrete approximation of Pareto front using multi-objective evolutionary algorithms have the problems of heavy computation burden, long running time and missing Pareto optimal points. In order to overcome these problems, an approach to continuous approximation of Pareto front using geometric support vector regression is presented. The regression model of the small size approximate discrete Pareto front is constructed by geometric support vector regression modeling and is described as the approximate continuous Pareto front. In the process of geometric support vector regression modeling, considering the distribution characteristic of Pareto optimal points, the separable augmented training sample sets are constructed by shifting original training sample points along multiple coordinated axes. Besides, an interactive decision-making(DM)procedure, in which the continuous approximation of Pareto front and decision-making is performed interactively, is designed for improving the accuracy of the preferred Pareto optimal point. The correctness of the continuous approximation of Pareto front is demonstrated with a typical multi-objective optimization problem. In addition,combined with the interactive decision-making procedure, the continuous approximation of Pareto front is applied in the multi-objective optimization for an industrial fed-batch yeast fermentation process. The experimental results show that the generated approximate continuous Pareto front has good accuracy and completeness. Compared with the multi-objective evolutionary algorithm with large size population, a more accurate preferred Pareto optimal point can be obtained from the approximate continuous Pareto front with less computation and shorter running time. The operation strategy corresponding to the final preferred Pareto optimal point generated by the interactive DM procedure can improve the production indexes of the fermentation process effectively. 展开更多
关键词 continuous approximation of PARETO front GEOMETRIC support vector regression Interactive DECISION-MAKING procedure FED-BATCH FERMENTATION process
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On Continuous Programming with Support Functions
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作者 Iqbal Husain Santosh K. Shrivastav Abdul Raoof Shah 《Applied Mathematics》 2013年第10期1441-1449,共9页
A second-order Mond-Weir type dual problem is formulated for a class of continuous programming problems in which both objective and constraint functions contain support functions;hence it is nondifferentiable. Under s... A second-order Mond-Weir type dual problem is formulated for a class of continuous programming problems in which both objective and constraint functions contain support functions;hence it is nondifferentiable. Under second-order strict pseudoinvexity, second-order pseudoinvexity and second-order quasi-invexity assumptions on functionals, weak, strong, strict converse and converse duality theorems are established for this pair of dual continuous programming problems. Special cases are deduced and a pair of dual continuous problems with natural boundary values is constructed. A close relationship between the duality results of our problems and those of the corresponding (static) nonlinear programming problem with support functions is briefly outlined. 展开更多
关键词 continuous PROGRAMMING SECOND-ORDER Generalized INVEXITY SECOND-ORDER DUALITY Nonlinear PROGRAMMING support Functions Natural BOUNDARY VALUES
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Second-Order Duality for Continuous Programming Containing Support Functions
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作者 Iqbal Husain Mashoob Masoodi 《Applied Mathematics》 2010年第6期534-541,共8页
A second-order dual problem is formulated for a class of continuous programming problem in which both objective and constrained functions contain support functions, hence it is nondifferentiable. Under second-order in... A second-order dual problem is formulated for a class of continuous programming problem in which both objective and constrained functions contain support functions, hence it is nondifferentiable. Under second-order invexity and second-order pseudoinvexity, weak, strong and converse duality theorems are established for this pair of dual problems. Special cases are deduced and a pair of dual continuous problems with natural boundary values is constructed. A close relationship between duality results of our problems and those of the corresponding (static) nonlinear programming problem with support functions is briefly outlined. 展开更多
关键词 continuous PROGRAMMING SECOND-ORDER INVEXITY SECOND-ORDER PSEUDOINVEXITY SECOND-ORDER DUALITY Nonlinear PROGRAMMING support Functions Natural Boundary VALUES
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Effects of Continuous Nursing and Nutritional Support on the Quality of Life of Patients with Primary Liver Cancer Undergoing Interventional Therapy
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作者 HANWenjuan 《外文科技期刊数据库(文摘版)医药卫生》 2022年第10期136-139,共4页
Objective: to analyze the application value of continuous nursing and nutritional support. Methods: 90 patients with primary liver cancer who received interventional therapy from January 2021 to June 2022 in the First... Objective: to analyze the application value of continuous nursing and nutritional support. Methods: 90 patients with primary liver cancer who received interventional therapy from January 2021 to June 2022 in the First Affiliated Hospital of Nanjing Medical University were selected and divided into two groups. The control group received routine nursing, while the observation group received continuous nursing and nutritional support. The differences of each index between the two groups were compared. Results: the changes of serum total protein, albumin and quality of life scores in the observation group were higher than those in the control group (P<0.05);The satisfaction of the observation group was higher than that of the control group (P<0.05). Conclusion: the combination of continuous nursing and nutritional support has a good application effect, which can improve the total protein and albumin levels of patients and can be popularized. 展开更多
关键词 continuous nursing nutritional support primary liver cancer interventional therapy
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Aerodynamic characteristics of co-flow jet wing with simple high-lift devices 被引量:3
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作者 Zhenhao ZHU Tianhang XIAO +2 位作者 Haolin ZHI Shuanghou DENG Yujin LU 《Chinese Journal of Aeronautics》 SCIE EI CAS CSCD 2022年第10期67-83,共17页
Numerical investigations are conducted to explore the aerodynamic characteristics of three-dimensional Co-Flow Jet(CFJ) wing with simple high-lift devices during low-speed takeoff and landing. Effects of three crucial... Numerical investigations are conducted to explore the aerodynamic characteristics of three-dimensional Co-Flow Jet(CFJ) wing with simple high-lift devices during low-speed takeoff and landing. Effects of three crucial parameters of CFJ wing, i.e., angle of attack, jet momentum and swept angle, are comprehensively examined. Additionally, the aerodynamic characteristics of two CFJ configurations, i.e., using open and discrete slots for injection, are compared. The results show that applying CFJ technique to a wing with simple high-lift device is able to generate more lift,reduce drag and enlarge stall margin with lower energy expenditure due to the super-circulation effect. Increasing the jet intensity can reduce the drag significantly, which is mainly contributed by the reaction jet force. The Oswald efficiency factor is, in some circumstances, larger than one,which indicates the potential of CFJ in reducing induced drag. Compared with clean wing configuration, using CFJ technique allows the aerodynamic force variation less sensitive to the swept angle, and such phenomenon is better observed for small swept angle region. Eventually, it is interesting to know that the discrete slotted CFJ configuration demonstrates a promising enhancement in aerodynamic performance in terms of high lift, low drag and efficiency. 展开更多
关键词 Active flow control Co-flow jet continuous injection Discrete injection slot simple high-lift device
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An Algorithm for Idle-State Detection and Continuous Classifier Design in Motor-Imagery-Based BCI 被引量:3
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作者 Yu Huang Qiang Wu Xu Lei Ping Yang Peng Xu De-Zhong Yao 《Journal of Electronic Science and Technology of China》 2009年第1期27-33,共7页
Abstract-The development of asynchronous brain-computer interface (BCI) based on motor imagery (M1) poses the research in algorithms for detecting the nontask states (i.e., idle state) and the design of continuo... Abstract-The development of asynchronous brain-computer interface (BCI) based on motor imagery (M1) poses the research in algorithms for detecting the nontask states (i.e., idle state) and the design of continuous classifiers that classify continuously incoming electroencephalogram (EEG) samples. An algorithm is proposed in this paper which integrates two two-class classifiers to detect idle state and utilizes a sliding window to achieve continuous outputs. The common spatial pattern (CSP) algorithm is used to extract features of EEG signals and the linear support vector machine (SVM) is utilized to serve as classifier. The algorithm is applied on dataset IVb of BCI competition Ⅲ, with a resulting mean square error of 0.66. The result indicates that the proposed algorithm is feasible in the first step of the development of asynchronous systems. 展开更多
关键词 Brain-computer interface competition common spatial pattern continuous classifier idle state motor imagery support vector machine.
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Outcomes of continuous flow ventricular assist devices
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作者 Shelly Bansal Chittoor B Sai-Sudhakar Bryan A Whitson 《World Journal of Surgical Procedures》 2014年第1期1-8,共8页
Heart transplantation is commonplace, the supply is limited. Many exciting changes in the field of mechanical circulatory support have occurred in the past few years, including the axial flow pump. Left ventricular as... Heart transplantation is commonplace, the supply is limited. Many exciting changes in the field of mechanical circulatory support have occurred in the past few years, including the axial flow pump. Left ventricular assist device(LVAD) therapy is ever evolving. As the use of LVAD therapy increases it is important to understand the indications, surgical considerations and outcomes. 展开更多
关键词 LEFT VENTRICULAR assist device AXIAL FLOW Mechanical circulatory support HEART failure continuous FLOW
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Impact of the United Network for Organ Sharing allocation criteria changes on temporary mechanical circulatory support use as a bridge to transplant
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作者 Sriram Sunil Kumar Shreya Arvind +7 位作者 Sanjana Nagraj Maisha Maliha Sumant Pargaonkar Vikyath Satish Sharanya Kaushik Kuan-Yu Chi Nikolaos Diakos Miguel Alvarez Villela 《World Journal of Transplantation》 2025年第4期144-156,共13页
Temporary mechanical circulatory support (tMCS) devices such as intra-aorticballoon pumps, veno-arterial extracorporeal membrane oxygenation, and percutaneousventricular assist devices, play a major role in supporting... Temporary mechanical circulatory support (tMCS) devices such as intra-aorticballoon pumps, veno-arterial extracorporeal membrane oxygenation, and percutaneousventricular assist devices, play a major role in supporting patients withend-stage heart failure and bridging them to transplant. In 2018, the United Networkfor Organ Sharing heart allocation criteria was modified by increasing thenumber of statuses in the heart transplant waitlist to differentiate and favor thesickest patients awaiting transplantation. Within this new system, patients withtMCS devices receive the highest priority statuses. While the 2018 allocationsystem has reduced waitlist times and mortality for the highest-priority patients,some studies have shown a concomitant rise in the utilization of tMCS devices asbridge to transplant after its enaction. In this narrative review, we describe thesechanges in tMCS utilization and provide insights on how the upcoming creationof a continuous distribution allocation system may further impact these trends. 展开更多
关键词 Mechanical circulatory support Heart transplantation Ventricular assist device Allocation criteria continuous distribution
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大中型水利水电工程移民后期扶持政策走向研究——以S省B水电工程移民调查为例
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作者 潘飞 崔洪梅 +4 位作者 孙中艮 石昕川 张铭 王馨瑶 朱徐骊 《水力发电》 2026年第1期32-37,共6页
国家大中型水库移民现状人口后期扶持将于2026年到期,到期后扶持政策是否延续是关注的焦点。以S省B水电工程移民为案例,在多源流理论基础上构建了经济、心理、政策合规性、社会融合与治理、参照方案评估体系,运用专家评估法评估政策到期... 国家大中型水库移民现状人口后期扶持将于2026年到期,到期后扶持政策是否延续是关注的焦点。以S省B水电工程移民为案例,在多源流理论基础上构建了经济、心理、政策合规性、社会融合与治理、参照方案评估体系,运用专家评估法评估政策到期后5个走向方案利弊,并开展量化比较。研究发现,“到期延续直发直补和项目扶持”综合表现最优。据此提出要科学延续大中型水库移民后期扶持政策,要将困难移民同步纳入国家公民救助体系,以及持续优化项目扶持建议。 展开更多
关键词 水库移民 后期扶持 政策延续 多源流理论
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三软地层建下充填开采技术研究与应用
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作者 邹玉龙 周景奎 +1 位作者 刘明明 万蕾 《煤矿现代化》 2026年第1期80-87,共8页
梁家煤矿是典型的软岩矿井,建(构)筑物下压煤严重,为解决建下压煤开采问题,积极寻求适合软岩条件的建下充填开采方法。鉴于软岩随采随冒的特性,制约瓶颈是没有充填时间和空间,基于对煤矿安全生产先进适用技术推广目录中连采连充工艺的... 梁家煤矿是典型的软岩矿井,建(构)筑物下压煤严重,为解决建下压煤开采问题,积极寻求适合软岩条件的建下充填开采方法。鉴于软岩随采随冒的特性,制约瓶颈是没有充填时间和空间,基于对煤矿安全生产先进适用技术推广目录中连采连充工艺的不断调研、分析,结合矿井实际,系统阐述了软岩矿井实施充填开采的可行性,通过优化工作面设计、充填工艺、支护工艺、封堵工艺等,有针对性制订了软岩条件下连采连充方案。配合锚杆测力计、顶板离层仪、充填体应力计和位移计等监测方法和工具,针对充填巷双帮、单帮制定差异化支护措施,规避了顶板下沉、帮部片落的风险,经现场应用,解决了软岩顶板维护问题,开创软岩矿井充填开采的先河,填补软岩充填开采技术空白,形成一套采用固体废物实施绿色开采关键技术。 展开更多
关键词 软岩充填 随采随冒 差异化支护 连采连充
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软基区变宽截面连续梁支架预压及梁体稳定性控制技术研究
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作者 黄保良 《建筑施工》 2026年第1期63-67,共5页
针对结构复杂、地基软弱及场地受限等问题,结合某铁路特大桥道岔连续梁施工,提出适用于双线变四线变截面桥梁的支架施工与稳定性控制技术。该技术综合采用钻孔桩+条形基础布设、鱼塘区回填换填、模块化支架拼装、静载分级预压与全过程... 针对结构复杂、地基软弱及场地受限等问题,结合某铁路特大桥道岔连续梁施工,提出适用于双线变四线变截面桥梁的支架施工与稳定性控制技术。该技术综合采用钻孔桩+条形基础布设、鱼塘区回填换填、模块化支架拼装、静载分级预压与全过程监测等手段,重点解决地基不均沉降、支架失稳及线形偏差控制难题。工程监测结果表明,支架最大沉降小于28.2 mm,梁体徐变变化平稳,结构响应良好。因此,相关设计、施工与监测策略可为同类型道岔梁结构支架施工提供可复制的技术路径与控制依据。 展开更多
关键词 铁路特大桥 道岔连续梁 支架施工 梁体徐变 沉降监测
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Factors influencing self-efficacy in breastfeeding support among public health nurses in Japan 被引量:2
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作者 Noriko Toyama Kayoko Kurihara +1 位作者 Mineko Muranaka Kiyoko Kamibeppu 《Health》 2013年第12期2051-2058,共8页
This study investigated self-efficacy in breastfeeding support among public health nurses (PHNs) working at maternal and child health (MCH) services in Japanese municipalities, and its related factors such as educatio... This study investigated self-efficacy in breastfeeding support among public health nurses (PHNs) working at maternal and child health (MCH) services in Japanese municipalities, and its related factors such as education, working experience, breastfeeding experience, and postgraduate/continuous education. Directors of the MCH divisions were requested to select one PHN to answer the self-report questionnaires sent. The questionnaires were collected from October 2010 to January 2011. Of the 1750 questionnaires sent, 831 were returned (response rate: 47.5%);102 were excluded from analysis because of missing data (valid response rate: 41.7%). After adjusting the weights of PHN sampling and collection rates by prefecture and population size, Model 1 of the multiple regression analysis showed that the self-efficacy in breastfeeding support was significantly higher in large/urban municipalities (β = 0.13) and in the Kanto district. Model 2 revealed that self-efficacy was significantly associated with working experience (β = 0.13) and breastfeeding experience (β = 0.22) but not with educational background. Model 3 showed that self-efficacy was significantly associated with postgraduate education (β = 0.14) and continuous education (β = 0.12). This suggested that PHNs’ self-efficacy increased through self-enrichment. It is necessary to create training opportunities about breastfeeding support for PHNs—especially those working in remote and/or small municipalities— and to provide them with new and important information. 展开更多
关键词 BREASTFEEDING support PUBLIC Health NURSE SELF-EFFICACY Postgraduate/continuous Education
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基于连续小波变换的CNN—SVM农机滚动轴承故障诊断 被引量:6
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作者 沈伟杰 肖茂华 +1 位作者 宋新民 项腾飞 《中国农机化学报》 北大核心 2025年第4期254-264,共11页
针对农用机械滚动轴承故障诊断中轴承振动信号非线性、非平稳特性以及故障特征表征不明显的问题,提出一种基于连续小波变换(CWT)、卷积神经网络(CNN)和支持向量机(SVM)的滚动轴承故障诊断方法(CWT—CNN—SVM)。首先,利用CWT对滚动轴承... 针对农用机械滚动轴承故障诊断中轴承振动信号非线性、非平稳特性以及故障特征表征不明显的问题,提出一种基于连续小波变换(CWT)、卷积神经网络(CNN)和支持向量机(SVM)的滚动轴承故障诊断方法(CWT—CNN—SVM)。首先,利用CWT对滚动轴承振动信号进行多尺度时频分析,为后续故障诊断提供更详细的特征;然后,将提取到的时频图作为输入,利用CNN深层次学习故障特征信息;最后,采用SVM对输出结果进行分类,以实现精确的故障类型识别。与BPNN、SVM、CWT—CNN以及CWT—ResNet等方法比较,试验结果表明,CWT—CNN—SVM故障诊断准确率最高,单次准确率达到100%,5次重复试验准确率为99.62%。CWT—CNN—SVM在处理复杂的滚动轴承故障诊断问题时,不仅诊断准确,同时展现出深度学习与故障诊断相结合的优势,能进一步提升小数据集的性能。所提出的CWT—CNN—SVM方法对于提升农机滚动轴承故障诊断性能,具有一定的理论价值和实际应用前景。 展开更多
关键词 故障诊断 农机 滚动轴承 连续小波变换 卷积神经网络 支持向量机
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考虑吊杆系统性失效的多跨下承式系杆拱桥强健性设计 被引量:2
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作者 范冰辉 孙绮 +1 位作者 陈宝春 陈康明 《交通运输工程学报》 北大核心 2025年第2期204-217,共14页
为研究吊杆系统性失效对下承式系杆拱桥产生的动力冲击效应,首先采用3种数值计算方法(LS-DYNA重启动法、生死单元法、全动力分析法)模拟吊杆断索效应,并与吊杆破断试验的动力响应数据进行对比,以选择最优的吊杆系统性失效模拟方法;其次... 为研究吊杆系统性失效对下承式系杆拱桥产生的动力冲击效应,首先采用3种数值计算方法(LS-DYNA重启动法、生死单元法、全动力分析法)模拟吊杆断索效应,并与吊杆破断试验的动力响应数据进行对比,以选择最优的吊杆系统性失效模拟方法;其次,为加强多跨下承式系杆拱桥结构的强健性和防连续性垮塌性能,提出先简支后连续结构、刚性整体式系杆拱结构2种形式的结构体系,采用失效模拟方法分析对比了结构改造前后吊杆系统性失效下剩余结构的动力响应,并利用Simple-Johnson-Cook模型对桥梁破坏过程进行仿真,获取结构最终破坏形态;在此基础上,探讨了吊杆系统性失效下结构的连续性垮塌破坏机理。研究结果表明:LS-DYNA重启动法的模拟结果与试验数据误差较小,能够更好地模拟吊杆瞬时破坏时的工况;先简支后连续结构在吊杆系统性失效下桥道系的最终破坏损伤程度最小,传力路径更长,可以有效地延缓结构的破坏历程,减小发生连续性垮塌事故的风险,为交通疏散争取时间;而刚性整体式系杆拱结构由于初始刚度较高,易引发应力集中,导致桥道系局部过早失效。因此,先简支后连续结构可适用于新建的多跨下承式系杆拱桥的设计,或可通过在墩顶设置可更换式节点,从而将其便捷地应用于既有桥梁的强健性改造中。 展开更多
关键词 桥梁工程 多跨下承式系杆拱桥 损伤失效模型 吊杆系统性失效 强健性设计 先简支后连续结构 刚性整体式系杆拱结构
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连采连充式工作面矿压叠加特征及围岩控制技术应用 被引量:1
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作者 杨涛 闵恒 +3 位作者 胡嘉英 陈全秋 张庆国 张书超 《中国安全生产科学技术》 北大核心 2025年第7期99-105,共7页
为解决特厚煤层在连采连充工艺中支巷围岩变形及稳定性难题,采用数值模拟与现场实验相结合的方法,揭示采动应力场时空迁移规律及围岩破坏机制,提出“深层锚索约束+浅层锚杆支护+双向护网”的差异化协同控制技术。研究结果表明:充填后可... 为解决特厚煤层在连采连充工艺中支巷围岩变形及稳定性难题,采用数值模拟与现场实验相结合的方法,揭示采动应力场时空迁移规律及围岩破坏机制,提出“深层锚索约束+浅层锚杆支护+双向护网”的差异化协同控制技术。研究结果表明:充填后可显著降低未开采支巷应力集中水平;充填体-煤柱复合结构因刚度差异导致显著非对称变形;通过“锚索约束深部岩体+锚杆强化浅层结构+护网协同承载”的差异化支护,实现围岩应力场均衡化调控。研究结果可为特厚煤层绿色高效开采提供理论与技术支撑。 展开更多
关键词 特厚煤层 连采连充 围岩控制 数值模拟 差异化支护
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汽车服务工程专业认证的教学评价体系与持续改进研究 被引量:3
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作者 闫晟煜 邱兆文 +1 位作者 牛世峰 张凯超 《高教学刊》 2025年第5期79-84,共6页
持续改进教学体系是提高教学质量并适应行业趋势的重要一环。以工程教育专业认证为契机,该文通过明确校院两级机构在教学过程中的管理职责,完善教学质量监控体系,提出汽车服务工程专业教学质量PDCA监控机制,建立课程对指标点的支撑算法... 持续改进教学体系是提高教学质量并适应行业趋势的重要一环。以工程教育专业认证为契机,该文通过明确校院两级机构在教学过程中的管理职责,完善教学质量监控体系,提出汽车服务工程专业教学质量PDCA监控机制,建立课程对指标点的支撑算法,形成以学年为周期的专业教学质量范式评价方法,完成培养目标、毕业要求、课程体系、课程目标等教学环节的测度与量化,提出教学评价体系的持续改进机制。对2019—2021届毕业生的毕业要求达成情况进行评价,评价表明该教学环节评价方法可行。闭环教学评价体系与持续改进机制可用于对全国同类院校汽车服务工程专业的专业认证自评与日常运行状况监测。 展开更多
关键词 汽车服务工程 专业认证 教学评价体系 OBE教育理念 持续改进 PDCA闭环监控
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无砟轨道铁路简支+刚构布置梁桥抗震设计
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作者 刘尊稳 李欣婧 +3 位作者 陈兴冲 韩国庆 韩峰 李媛 《铁道工程学报》 北大核心 2025年第5期43-49,共7页
研究目的:我国西部地区高速铁路桥梁设计较多采用双块式无砟轨道简支+刚构布置梁桥,针对该类桥梁结构的抗震设计问题,分别建立传统计算模型、考虑轨道系统约束和同时考虑钢轨约束的线桥一体化模型共三种模型,同时针对不同沟谷区域调整... 研究目的:我国西部地区高速铁路桥梁设计较多采用双块式无砟轨道简支+刚构布置梁桥,针对该类桥梁结构的抗震设计问题,分别建立传统计算模型、考虑轨道系统约束和同时考虑钢轨约束的线桥一体化模型共三种模型,同时针对不同沟谷区域调整刚构桥联数和墩高,运用反应谱法研究各结构体系的地震响应规律。研究结论:(1)轨道系统及两端钢轨的约束作用均减小了引桥桥墩的地震响应,但主桥上轨道系统的存在会增大刚构边墩的墩底弯矩,钢轨的约束作用影响则较小;(2)在线桥一体化模型中,随着刚构桥联数的增加,刚构墩的耗能能力会加强,但随着墩高增加,主要耗能构件会转为刚构边墩;(3)轨道系统的存在能抑制全桥的墩顶位移,但随着刚构桥联数的增加,抑制作用会减弱;(4)主跨刚构为一联、三联时,轨道应力分别呈“V”“U”字形分布,应力峰值位于刚构边墩梁缝处,建议在该处进行特殊设计以应对应力集中;(5)本研究成果可为我国西部地区高铁桥梁的抗震设计提供一定的科学依据。 展开更多
关键词 西部地区高速铁路桥梁 双块式无砟轨道 简支+刚构布置梁桥 线桥一体化模型 抗震设计
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四点简支矩形板振动特性半解析求解方法
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作者 李志强 闫兴 +2 位作者 侯传涛 程昊 王博 《强度与环境》 2025年第3期1-9,共9页
仪器设备中大量使用了四点简支状态矩形电路板结构,电路板结构的动力学特性对于电路板结构设计的频率管理、疲劳寿命设计有着重要的意义。本文针对电路板结构设计阶段中一阶频率快速预示的需求,开展四点简支矩形板振动特性半解析求解方... 仪器设备中大量使用了四点简支状态矩形电路板结构,电路板结构的动力学特性对于电路板结构设计的频率管理、疲劳寿命设计有着重要的意义。本文针对电路板结构设计阶段中一阶频率快速预示的需求,开展四点简支矩形板振动特性半解析求解方法研究。提出了一种四点简支状态矩形板试函数表示形式,采用迭代抽样计算方式代替泛函变分方式求解试函数中的待定系数,最后基于Rayleigh-Ritz法完成四点简支矩形板一阶频率及模态振型的求解。半解析求解方法与有限元计算结果对比表明:半解析计算方法对迭代次数、网格密度不敏感,收敛性较好。对于长宽比小于1.8的矩形板,计算误差不超过8%,且计算时间极短。该方法可以应用于四点简支电路板一阶频率及疲劳寿命估算中,为仪器设备电路板结构设计提供有力的支撑。 展开更多
关键词 Rayleigh-Ritz法 四点简支 半解析 电路板 矩形板
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高速铁路CRTSⅢ型无砟轨道-减隔震桥梁系统地震响应分析
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作者 张永亮 毕明辉 郑佳轩 《世界地震工程》 北大核心 2025年第4期40-49,共10页
为研究高速铁路轨道-减隔震桥梁系统的纵向地震响应及损伤状态,以桥面铺设CRTSⅢ型无砟轨道结构的7跨32 m简支梁桥为研究对象,建立了轨道-桥梁系统有限元模型,通过非线性时程分析获得了系统在不同的地震波、地震动强度及支座类型下各关... 为研究高速铁路轨道-减隔震桥梁系统的纵向地震响应及损伤状态,以桥面铺设CRTSⅢ型无砟轨道结构的7跨32 m简支梁桥为研究对象,建立了轨道-桥梁系统有限元模型,通过非线性时程分析获得了系统在不同的地震波、地震动强度及支座类型下各关键构件的地震响应分布规律。结果表明:纵向地震激励下梁体位移呈阶梯形分布,最大值出现在桥跨中心处;扣件位移最大值出现在桥台伸缩缝处,且在每跨梁端伸缩缝处出现极值,扣件位移受不同地震波的频谱特性影响显著。钢轨应力最大值出现在边跨两侧的伸缩缝处,复合板截面正应力由轴力和弯矩分量共同引起。支座及轨道系统进入非线性后,与地震动强度增加幅度相比,易损构件纵向变形的增幅表现出显著的放大效应及分布不均衡性。考虑轨道系统,与摩擦摆支座相比,同球向双球面支座可明显降低扣件、梁体及支座的位移响应;轨道系统对支座位移具有显著的抑制作用。 展开更多
关键词 高速铁路 简支梁桥 CRTSⅢ型轨道系统 减隔震 地震响应
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