Crashworthiness design and experimental validation of a novel collision post structure for subway cab cars

This paper proposes a novel collision post structure designed to improve the crashworthiness of subway cab cars.The structure provides two innovative features:1)a simpler connection between the post and the car roof,which gives a more reasonable load transfer path to reduce the stress concentration at the joint;and 2)a stiffness induction design that provides an ideal deformation model to protect the safe space of the cab cars.The novel collision post structure was evaluated with finite element analysis,and a prototype cab car was mechanically tested.The results demonstrate that the deformation response was stable and agreed well with the expected ideal mode.The maximum load was 874.17 kN and the responses remained well above the elastic design load of 334 kN as required by the design specification.In addition,there was no significant tearing failure during the whole test process.Therefore,the novel collision post structure proposed has met the requirements specified in new standard to improve the crashworthiness of subway cab cars.Finally,the energy absorption efficiency and light weight design highlights were also summarized and discussed.

Finite element analysis on nut post structure of Three Gorges Project ship lift

A nonlinear finite element model of the nut post reinforced concrete （RC） structure of the safety mechanism in the Three Gorges Project （TGP） ship lift was built by ANSYS software. Some irregular structures such as the nut post and the rotary rod were divided by curved surface into a series of regular parts, and the structures were all meshed to hexahedron. Constraint equations were defined between two interfaces with different element sizes and mesh patterns. PRETS179 elements were used to simulate the preload in the tendons and the pre-stressed screws, and the loss of prestressing force was calculated. Five extreme load cases were analyzed. The stress of each part in the structure was obtained. The results indicate that the maximum compressive stress of concrete C35 is 24.13 MPa, so the concrete may be partially crushed; the maximum tensile stress of the grouting motar is 6.73 MPa, so the grouting motar may partially fracture; the maximum yon Mises stress of the rotary rod is 648.70 MPa, therefore the rotary rod may partially yield.

Innovative Applications of Post-Tension for Restoration and Rehabilitation of Bridges and Structures--Case Studies in India

This paper deals with new and innovative case studies of application of post-tensioning for restoration of structures for buildings, bridges and rock stabilization in India. In earlier situations for these types of cases conventional method of repair and rehabilitation has been used. These innovative approaches for restoration have led to enormous saving of cost and time. The advantages of post tensioning are well known in the civil industry and are being used for the last 40 to 50 years. Post tensioning is one of the best methods to induce stresses in the concrete before application of live load and this technique can also be widely used for restoration and rehabilitation of structures. Unlike the use of post-tensioning in new structures there are no definite methods or codes for application in restoration and rehabilitation of structures. For restoration and rehabilitation of structures, PT （post tensioned） technique can be applied in combination with other techniques and materials available. Bridge lifting is a tricky and risky job especially when the superstructure is displaced appreciably by a natural calamity, etc.. Not only the present state of structure needs proper study before commencement of restoration and rehabilitation but also calls for careful execution. This paper deals with case studies of innovative applications of post tensioning in restoration and rehabilitation of structures and restoration of bridge structure in Andaman ＆ Nicobar Island, India affected by Sumatra quake.

Barrellite and Pillarrite: A Description and a Mode of Formation of a Novel Post-Sedimentary Twin Structures from As-Subbiyah, North of Kuwait Bay, Kuwait

I report on the occurrence of a pair of novel and related post-sedimentary structures that form in the Neogene cross-bedded red sandstones in the As-Subbiyah area, north of Kuwait Bay, Kuwait. I named them barrellite and pillarrite. Barrellite forms as vertical tubes of concentric sheaths of siltstone with partially hollow interior or intervening homogeneous and structure-less sandstone. It stands as barrels above the background sandstone. Pillarrite forms as discrete, vertical and solitary spines of homogeneous sandstone and siltstone, or inside barrellite masses from which successive siltstone sheaths were stripped. The structures range in diameter from one-centimeter poke marks to one-meter-wide barrels and hunks, and their vertical length exceeds two meters. Barrellite, pillarrite and their complex intergrowths develop near thin quartz veins and chaotic zones, and form with them complex geometrical relationships. The dual structures are genetically related and fall within the general class of tubular structures in sedimentary rocks. I consider them as a special type of sand injectites. The mode of formation of these structures is enigmatic. They develop in a geological setting that displays evidence of a widespread and vigorous oil field brine. I suggest a tentative scenario for their formation, involving flushing of the brine through hydraulic fracturing of the sedimentary succession above the Ebharah Oil Field reservoir in the As-Subbiyah area. The brine plucks mineral and rock fragments and mixes with them along its paths, producing a heterogeneous slurry. Ultimately, the slurry solidifies as barrellite and pillarrite, chaotic zones and quartz veins. The vertical nature of the structures, circular and internal concentric arrangements, as well as the homogenous lithology inside their masses mimic characteristics of flow and deposits in vertical and horizontal pipelines.

Analysis of nonlinear stability and post-buckling for Euler-type beam-column structure

Based on the assumption of finite deformation, the Hamilton variational principle is extended to a nonlinear elastic Euler-type beam-column structure located on a nonlinear elastic foundation. The corresponding three-dimensional （3D） mathematical model for analyzing the nonlinear mechanical behaviors of structures is established, in which the effects of the rotation inertia and the nonlinearity of material and geometry are considered. As an application, the nonlinear stability and the post-buckling for a linear elastic beam with the equal cross-section located on an elastic foundation are analyzed. One end of the beam is fully fixed, and the other end is partially fixed and subjected to an axial force. A new numerical technique is proposed to calculate the trivial solution, bifurcation points, and bifurcation solutions by the shooting method and the Newton- Raphson iterative method. The first and second bifurcation points and the corresponding bifurcation solutions are calculated successfully. The effects of the foundation resistances and the inertia moments on the bifurcation points are considered.

The Appreciation of “Everyday Use” from the Perspective of Post-structuralism

"Everyday Use" is well-known story written by Alice Walker, who is a very famous black female writer. This paper will focus on using the decontructionism strategy to dismantle the binary oppositions of the story. The binary oppositions are "Pretty VS. Ugly, Civilized VS. Unenlightened, Hang VS. Use and The Mainstream Culture VS. Non-mainstream Culture". By analyzing, the paper concludes that no culture can be defeated and each culture needs to be passed on. Different cultures should respect each other.

Remote structural health monitoring with serially multiplexed fiber optic acoustic emission sensors

Development and testing of a serially multiplexed fiber optic sensor system is described.The sensor differs from conventional fiber optic acoustic systems,as it is capable of sensing AE emissions at several points along the length of a single fiber.Multiplexing provides for single channel detection of cracks and their locations in large structural systems. An algorithm was developed for signal recognition and tagging of the AE waveforms for detection of' crack locations,Labora- tory experiments on plain concrete beams and post-tensioned FRP tendons were pcrlormed to evaluate the crack detection capability of the sensor system.The acoustic emission sensor was able to detect initiation,growth and location of the cracks in concrete as well as in the FRP tendons.The AE system is potentially suitable lot applications involving health monitoring of structures following an earthquake.

张力腿平台POST结构强度分析

为确保深海中张力腿平台(TLP)结构的安全和可靠运行,针对TLP平台关键部位:连接船体与上部组块的对接立柱(POST)的结构强度,采用ANSYS软件建立TLP平台的"POST"结构模型,分析在位工况:一年一遇、百年一遇以及千年一遇等环境条件下的POST结构强度,确定POST这一TLP关键结构满足强度要求,计算分析结果合理,可为TLP平台的POST结构强度评估提供参考。

Photovoltaic Properties of CdSe Quantum Dot Sensitized Inverse Opal TiO₂Solar Cells: The Effect of TiCl₄Post Treatment

Recently, semiconductor quantum dot (QD) sensitized solar cells (QDSSCs) are expected to achieve higher conversion efficiency because of the large light absorption coefficient and multiple exciton generation in QDs. The morphology of TiO2 electrode is one of the most important factors in QDSSCs. Inverse opal (IO) TiO2 electrode, which has periodic mesoporous structure, is useful for QDSSCs because of better penetration of electrolyte than conventional nanoparticulate TiO2 electrode. In addition, the ordered three dimensional structure of IO-TiO2 would be better for electron transport. We have found that open circuit voltage Voc of QDSSCs with IO-TiO2 electrodes was much higher (0.2 V) than that with nanoparticulate TiO2 electrodes. But short circuit current density Jsc was lower in the case of IO-TiO2 electrodes because of the smaller surface area of IO-TiO2. In this study, for increasing surface area of IO-TiO2, we applied TiCl4 post treatment on IO-TiO2 and investigated the effect of the post treatment on photovoltaic properties of CdSe QD sensitized IO-TiO2 solar cells. It was found that Jsc could be enhanced due to TiCl4 post treatment, but decreased again for more than one cycle treatment, which indicates excess post treatment may lead to worse penetration of electrolyte. Our results indicate that the appropriate post treatment can improve the energy conversion efficiency of the QDSSCs.

Nonlinear thermo-structural behavior of sandwich panels with truss cores under through-thickness gradient temperature field

A theoretical analysis is presented to predict the nonlinear thermo-structural response of metallicsandwich panels with truss cores under through-thickness gradient temperature field, which is acommon service condition for metallic thermal protection system （TPS）. The in-planetemperature distribution is assumed to be uniform, and through-thickness temperature field isdetermined by heat conduction. Two typical conditions are analyzed： nonlinear thermal bendingin fixed inside surface temperature, and thermal post-buckling in fixed temperature differencebetween two surfaces. Temperature-dependent mechanical properties are considered, andgradient shear stiffness and bending stiffness due to non-uniform temperature is included. Resultsindicate that the temperature-dependent material properties obviously affect bending resistance;however, the effect is negligible on post-buckling behavior. Influences of geometric parameters onthe thermo-structural behavior of the sandwich panel according to the present theoretical modelare discussed.

关于小学英语单课教学中Post-task部分的语用情境创设研究

语用情境创设是目前小学英语课堂操练的主要教学方法之一。文章主要研究单课中Post—task部分的语境创设。在辨析单课中Post—task语境创设基本涵义的基础上，运用翔实的案例对Post-task语境创设的原则和方法进行了深入的研究，最后进一步讨论了语境创设时应注意的几个问题。

基于后结构化技术的临床病种库系统设计与应用

目的:为解决传统临床病种库系统存在的依赖大量人工判断、缺乏辅助标注、电子病历数据可用性差等问题,设计一种基于后结构化技术的临床病种库系统。方法:先通过I2B2标准以及双向长短期记忆网络(bi-directional long short-term memory,BiLSTM)模型构建实体识别模型,形成病历模板库,然后组合病历模板库形成关系模板,抽取复杂的医学实体,实现电子病历的后结构化。之后,基于电子病历后结构化技术构建包括病历结构化、结构化评估、数据标注、常规功能和系统管理5个模块的临床病种库系统。结果:该系统可以将电子病历文本转化为结构化语言,提供更精细化的数据要素提取、更智能的结构化服务,提高了临床和科研工作的效率。结论:该系统提高了临床病种的数据可用性,减轻了用户数据加工的工作强度,保证了数据应用的高质量,为医学研究、临床辅助决策打下了坚实的基础。

区域产业结构对灾后恢复韧性的影响——以汶川县和北川县为例

灾后恢复是评价地震恢复韧性的重要指标。不同的区域经济产业所提供的就业数量存在差异,将对灾后恢复韧性产生极大影响。该文基于5.12汶川地震中受灾最严重的汶川县和北川县共736户受灾家庭的灾后恢复调查,研究了区域产业结构对恢复韧性的影响。研究表明:北川的家庭生活恢复滞后汶川近2年,主要是由于北川的外地务工家庭比例(49.60%)高于汶川(5.79%),这些受灾家庭恢复重建的主要资金来源是外地务工,但家庭成员长期外出不能参与恢复重建,造成其灾后恢复缓慢。外地务工家庭比例高的原因是北川第一产业占比高达27.20%,汶川仅为8.40%,第一产业所提供的本地就业数量远低于第二产业。因此,农业产业为主地区是灾后恢复最缺乏韧性的地区,需要大力提高防灾减灾能力,也可以通过产业结构调整,提高韧性。

基于自动纤维定量技术研究卒中后抑郁的纤维束改变

目的通过自动纤维定量(automated fiber quantification,AFQ)技术研究卒中后抑郁(post-stroke depression,PSD)神经纤维束的结构改变,并探索与抑郁程度相关的纤维节段。方法纳入单部位前循环脑梗死患者,分为PSD组和卒中后非抑郁(non-PSD)组,收集发病1个月时的汉密尔顿抑郁量表(Hamilton depression scale,HAMD)和MRI数据,采用AFQ提取神经纤维束节段的部分各项异性(fractional anisotropy,FA),评估纤维束节段FA组间差异,以及差异纤维束节段FA与HAMD的相关性。结果共收集8例PSD和18例non-PSD患者。与non-PSD组相比,PSD组胼胝体、左侧下纵束和钩状束的节段FA降低(P<0.05)。所有患者胼胝体小钳(r=-0.418,P=0.047)和左侧钩状束(r=-0.467,P=0.029)部分节段FA与其HAMD呈负相关。结论AFQ精确地揭示了PSD患者的神经纤维束存在节段性的微结构损害,且胼胝体小钳和钩状束节段性微结构损害与抑郁严重程度有关。

后结构主义视角下旅游资源课程教学模式优化研究

课程是人才培养的核心要素,而高质量的旅游资源课程教学是高素质应用型旅游人才培养的重要环节。为解决结构主义思想下旅游资源课程教学模式与旅游教育发展方向和人才培养需求不适应的局面,文章按照后结构主义的“解构—建构”思维,对旅游资源课程教学模式进行了改革,从教学目标生成逻辑优化、教学内容模块体系建构、教学环境角色场景整合及教学过程理念方法转向等4个方面进行了提升。实践结果表明:教学模式是提供解决课程问题分析思路和方法的动态变化过程,面向国家战略要求和产业需求是教学模式不断创新演进的动力,教学模式路径创新是课程思政建设和新时代教学改革的必然要求,而后结构主义视角下的教学模式优化符合旅游人才培养的现实需求。

基于卷积神经网络的RC框架通信机楼震后损伤评定方法

为解决震后大量钢筋混凝土框架通信机楼损伤评定需求,基于卷积神经网络研究从构件层次至整体结构的损伤评定方法。首先对汶川地震、鲁甸地震、芦山地震等多次地震后大量钢筋混凝土框架结构损伤调查图片筛选处理,建立了钢筋混凝土框架梁、柱损伤评定数据集。然后通过对3个关键问题的研究建立了钢筋混凝土框架基于卷积神经网络的震损评定方法:训练和建立YOLOv5网络模型完成从结构震害照片中检测识别出梁、柱构件的任务,并改进优化了YOLOv5网络模型的检测性能;优选比较3种网络模型(ResNet50、MobileNetV2和AlexNet模型)对梁、柱构件损伤水平评定的精确性,最终建立了基于ResNet50的梁、柱构件损伤评定模型;给出了从构件层次到整体结构的损伤水平确定方法,并通过对一栋实际震损框架进行损伤评定验证了文中方法的可用性。结果表明,文中方法与专家的损伤评定结论一致性高,优化后的卷积神经网络模型精确度和稳定性好,对震后钢筋混凝土框架结构损伤评定具有良好的适用性。

大庆SN油田东部过渡带油水边界综合确定

为确定大庆SN油田东部过渡带油水界面,综合钻井、测井、地震资料,结合岩心含油产状分析和老井油水层二次解释,基于双相介质理论的叠后属性油气检测以及基于叠前地震波形指示反演的流体识别等技术,探讨构造油气藏外扩区油水边界的综合确定方法。研究区油水边界具有以下特征:岩心含油产状为油斑以上;测井解释外推为油层或油水同层;叠后属性低高频能量比大于0.85;叠前反演预测含水饱和度小于75%。因此,以“井点定深度、地震定边界、动态来验证”为原则,从“点—线—面—空”,经过综合分析,确定最终油水边界位置。研究成果有效指导了研究区外扩评价部署,对同类型构造油田油水边界研究具有参考意义。

寒区某超长隔震结构建造全过程温缩变形分析

针对严寒地区某超长隔震结构建造周期长、平面形状复杂、结构跨度大、季节温差显著及分阶段施工的特点,建立了超长隔震结构建造全过程隔震层温缩变形的计算方法,结合现场的施工进度、方案和步序,采用有限元软件对建造全过程进行了详细的模拟,分析了结构建造全过程隔震层的温缩变形大小及演化规律,并与现场实测结果进行对比验证,最后探讨了结构分阶段施工、施工路径及后浇带设置方式对隔震层温缩变形的影响规律.结果表明:建造全过程温缩变形的模拟结果与实测结果吻合较好,隔震层的温缩变形随着施工进度推移大体呈周期性变化,且与环境温度变化有很大的相关性;超长隔震结构分阶段施工时,各阶段结构之间存在相互约束作用,结构最终的温缩变形是各阶段结构协调变形的结果;合理的施工路径和结构单元划分,能有效减小隔震层的温缩变形;相较于不设置后浇带的情形,当结构后浇带处附加钢筋连通时,隔震层最大温缩变形仅降低了6.3%,而当后浇带处钢筋全部搭接时,隔震层最大温缩变形降低36.3%.

半密闭腔室内冲击闪络电弧观测及弧后气体逸散过程研究

多腔室灭弧装置可保护绝缘子、抑制故障电弧存续,具有成为配电网线路防护增补措施的潜力。半密闭腔室作为多腔室灭弧装置的基本单元,腔室内冲击闪络电弧演变进程尚缺乏完备的观测手段和针对不同电极结构的直观对比,以及弧后气体状态的量化分析。为进一步完善半密闭腔室内电弧演变过程观测方法,优化结构设计,该文搭建了用于观测半密闭腔室电弧及弧后气体演变的高速纹影系统,对比分析了开放气隙与半密闭腔室气隙、U型电极和球形电极下半密闭腔室内冲击闪络电弧演变过程,根据纹影图像数据定义密度恢复率,并采用光流法探讨了弧后气体逸散过程中气体密度恢复和速度场分布。电弧演变过程的纹影图像表明,半密闭腔室较开放气隙具有主动“吹弧”作用,由于自感应磁场的分布差异,U型电极较球形电极加速腔室内电弧运动;弧后气体演变为近似涡环结构,促使腔室出口邻近区域气体密度率先恢复,空气自恢复能力得到提升。

科研机构自主确定专业技术岗位结构比例的探索与思考——江苏省某科研机构的实践分析

在部分高校、科研院所开展自主确定主系列专业技术岗位结构比例试点,是事业单位人事制度改革的一项创新尝试。江苏省某研究院作为先期省属试点单位之一,在自主设岗试点中,根据“三定”方案和院战略发展规划,区分主、辅系列专业技术岗位,构建岗位结构比例模型;从专业技术能力发展和公益职能履行的角度,明确各级各类岗位职责和能力需求;通过完善“竞聘上岗”“多维激励”“立体评价”等机制,有机整合岗位聘任、考核评价、表彰奖励、福利保障、教育培训等规章制度,形成全面的人事管理体系,规范引导各级各类人员立足岗位干事创业。