Seismic response analysis of continuous rigid frame bridge considering canyon topography effects under incident SV waves

To evaluate the importance of the canyon topography effects on large structures, based on a rigid frame bridge across a 137-m-deep and 600-m-wide canyon, the seismic response of the canyon site is analyzed using a two-dimensional finite element model under different seismic SV waves with the assumptions of vertical incidence and oblique incidence to obtain the ground motions, which are used as the excitation input on the pier foundations of the bridge with improved large mass method. The results indicate that canyon topography has significant influences on the ground motions in terms of inci- dent angle. The peak ground acceleration values vary greatly from the bottom of the canyon to the upper comers. Under ver- tical incident SV waves, at the upper comers of canyon the peak ground accelerations greatly increase; whereas the peak ground accelerations diminish at the bottom comers of canyon. Under oblique incident SV waves, the shaking of the canyon slope perpendicular to the incidence direction is much more severe than that of the opposite side of canyon. And the ground surface has been characterized by larger deformations in the case of oblique incident waves. It is also concluded that the low piers and frame of the continuous rigid frame bridge ape more sensitive to the multi-support seismic excitations than the flexible high piers. The canyon topography as well as the oblique incidence of the waves brings the continuous rigid frame bridge severe responses, which should be taken into account in bridge design.

AIRCRAFT CONCEPT EVALUATION AND EFFECTIVENESS-BASED DECISION-MAKING

Based on effectiveness analysis , a novel method is presented for combat aircraft top-hierarchy concept evaluation and decision-making. Applying multi-criterion decision-making ( MCDM ) and analytic hierarchy process , the new method can help to overcome the limitations of existing evaluation systems and decision-make methods.The proposed method includes the following process :( 1 ) Establish a multi-criterion and multi-hierarchy evaluation attribute system by introducing combat effectiveness ;( 2 ) Assign weight to the attributes and normalize them ;( 3 ) Evaluate and decision-make top-hierarchy aircraft concept based on effectiveness to reach a satisfactory design by comprehensively applying four multi-criterion decision-making methodologies , i.e.grey correlation projection method , weighted summation method , weighted quadrature method and ideal solution decision-making method , while considering the attribute hierarchy system and the logical relations among the attributes.Finally , an example is given to indicate the validity and feasibility of the proposed method.

Structural optimization of a reusable seismic frame active link

Circular design encompasses the use of inventive construction methodologies that possess the capability to be readily dismantled,repurposed,or recycled upon reaching the conclusion of their functional lifespan.This work specifically examines the creation of a reusable design case-study idea for seismic frame design,which is commonly employed in steel-frame constructions in New Zealand.A reusable optimized design for the full seismic frame was proposed in the research.Optimizing the dimensions of welded structures,whether in terms of weight or cost,leads to a decrease in the weight of the steel utilized.The decrease in weight is directly associated with a decrease in environ-mental impact,as the environmental impact is directly proportional to the mass of the construction.The environmental consequences associated with welding technique are contingent upon the dimensions of the weld,hence exerting an indirect influence on the overall mass of the structure.Given the presence of mass dependence in all three areas,albeit in distinct manners,this work employed a multi-objective function optimization strategy to simultaneously address these areas while also partially evaluating them separately.On this way substantial reductions can be achieved both at structural mass and environmental effects.

Application of Fuzzy Decision-Making Theory and Conflict-Resolution Method to Failure Mode and Effect Analysis of Industrial Valve

It is not objective to rate the decision-making factors in the traditional failure mode and effect analysis,so fuzzy semantic theory is used in this paper.Six fuzzy semantic scales and their corresponding semantics are summarized,and a defuzzification method is studied to obtain the fuzzy value table of the six fuzzy semantic scales.For the conflicts between experts in the traditional failure mode and effects analysis,a conflict-resolution algorithm is studied to obtain the failure risk order.Finally,a certain type of industrial valve is used as an example to prove the validity of the theory proposed in this paper.

Decision-making Principles and Evaluation Frame of Harmonious Fiscal Policy

Harmonious fiscal policy is the Inner requirement for Constructing Harmonious society and is an important means of realiziug such society. The harmonious fiscal policy should realize the harmony of “two hands”, the harmony of values, the unity of short-term and long-term harmony the unity of parts and the whole harmony, the unity of internal and external efficacy harmony. To scientifically evaluate harmony of fiscal policy is the prerequisite to bring harmonious fiscal policy to its full play.

Topographic effects on seismic response of long-span rigid-frame bridge under SV seismic wave

Seismic ground motions of two neighboring mountains and the free surface between them are calculated under the SV seismic waves with three different incident angles. The results are then taken as the inputs of multi-point seismic excitations for the foundation of a long-span bridge built over the valley in the analysis considering the integrated influence of traveling wave and topography. On the basis of a dynamic analytical method, a finite element model is created for the seismic responses of a four-span rigid-frame bridge of 440 m. The pier-top displacement and the pier-bottom internal force of the bridge are calculated. Then the results are compared with those considering traveling-wave effect only. The conclusions can serve as a seismic design reference for the structures located on the complex mountain topography.

基于特效合成软件After Effects的文字动画应用创作

After Effects是一款非常优秀的影视后期合成软件,它采用基于层的工作方式,可以非常方便地调入Photoshop、Illustrator等层文件,对多层图像进行控制;关键帧、路径概念的引入,使Af-ter Effects对于控制高级的二维动画游刃有余;而令人眼花缭乱的特技、特效系统,更能够实现使用者的创意。因此,After Effects在电视节目的片头制作和包装上,可以发挥重要的作用。文章主要以文字动画为实例介绍After Effects的基本使用。

Analysis of Second-Order Effect in Frame

The second order effect is the interaction between the vertical load and the deformation in a vertically forced element. In order to deduce a more brief but practical method, which has considered the second order effect in a sway frame, some factors which affect the second order deformation in a sway frame should be generalized based on a more accurate method. Nonlinear finite element is adopted in this paper, and according to this theory, a program, which can calculate the inner force and the deformation of the sway frame considering the second order effects is coded.

Frequency Analysis on the Data of Field Fertilizer Efficiency Test and Fertilization Decision-making

To solve the problems of abnormal larger, abnormal lower or even negative of target yield and fertilizing amount recommended by part of non-typical fertilizer effect equations using agricultural experiments and statistical analysis software,Yangzhou analyzer（2.2）, regression analysis of Excel, which objected to local actual production, the study adopted the principle and method of basic knowledge and the frequency of using probability theory, and carried out statistical analysis on the rape field fertilizer experiment data by frequency analysis method, the rape yield after optimizing fertilizing amount was 1 732.4 kg/hm^2, the ranges of N, P and K optimal combinations were： N=210.36-149.64 kg/hm^2,P2O5=81.89-58.11 kg/hm^2, K2O=81.89-58.11 kg/hm^2,which was consistent with local actual production. This study was based on frequency analysis, using weighted average method to determine the production combinations of different yield objectives, hereinto, the combinations with high yield, high frequency of occurrence（dependable crop） and fertilizer-saving were viewed as the optimizing production measures, and they had the merits of increasing fertilization decision-making information, reducing or avoiding the risk of small probability event. The results of this study can solve the problem of abnormal values fertilizing amount and target yield recommended by non-typical fertilizer effect function, which did not accord with local actual production, caused by Yangzhou analyzer（2.2）, regression analysis of Excel, and DPS statistical analysis software. For the fertilizer effect function equation established by regression analysis which did not reach significance level using variance analysis, whether the method can be adapted to for carrying out fertilization decision-making, recommending optimization combinations of N, P and K fertilizers and yield under optimized fertilizing amount should be further researched in future working practice.

Frame Dragging Effect on Properties of Rotating Neutron Stars with Strong Magnetic Field

The general relativistic frame dragging effect on the properties,such as the moments of inertia and the radiiof gyration of fast rotating neutron stars with a uniform strong magnetic field,is calculated accurate to the first orderin the uniform angular velocity.The results show that compared with the corresponding non-rotating static sphericalsymmetric neutron star with a weaker magnetic field,a fast rotating neutron star(millisecond pulsar)with a strongermagnetic field has a relative smaller moment of inertia and radius of gyration.

关于在After Effects中输出高清视频的研究

通过对用户需要、视频格式、编码格式、帧速率、分辨率等几个方面的分析,对在After Effects中输出高清视频进行了研究。

考虑台地效应的泸定6.8级地震某框架结构震害调查与分析

2022年9月5日四川省泸定县发生6.8级地震,在磨西台地上某框架结构的震害调查中,发现其东区和西区的框架结构出现不同程度的震害,且差异明显。其中,东、西区框架的首层柱上端均发生了“强梁弱柱”型破坏,西区框架中等及以上破坏等级的比例达到81%,而东区框架仅为13%,呈现出与台地边缘的强关联性。为分析东、西区框架结构震害差异的原因,采用FK-SEM方法分析了磨西台地的地震放大效应。计算结果表明,距离台地边缘越近,地震放大系数越大。其中,水平和竖向的地震放大系数在西区建筑场地分别为2.30和2.25,而在东区建筑场地则分别为2.01和1.99。在此基础上,采用磨西台站的地震动记录,对东、西区框架结构进行了震害模拟,分析了其破坏原因。研究结果表明:磨西台地边缘的地震影响系数的实际放大系数超过了《抗规》规定,存在不利地段影响和近场地震效应叠加的情况,仅按《抗规》不利地段进行考虑,多层框架结构难以实现“大震不倒”的设防目标;竖向地震作用是框架柱下端破坏的直接原因,主要破坏形态为偏拉、偏压破坏,水平地震作用导致其二次破坏;“仿雀替”构造对结构整体变形能力不利,是框架结构“强梁弱柱”型破坏的主要原因。根据震害调查和分析结果,建议在9度近断层设防地区,靠近台地边缘的多层框架结构,设计前宜对建筑场地进行分析,并考虑竖向地震的影响;在有民族特色的建筑设计中,应将“仿雀替”等装饰物与框架脱离,设计为非结构构件,以减少其对框架结构抗震性能的不利影响。

短视频平台公共政策传播的信息框架效应——基于“双减”政策的视频内容分析与实验

[目的/意义]短视频作为新兴的互联网信息表达方式,已逐渐成为政策传播的重要工具。探索短视频平台在公共政策信息传播中的效力以及受众采纳意愿,有助于提升公共政策传播效果。[研究设计/方法]以“双减”政策为例,根据框架效应理论和信息采纳理论,通过内容分析法归纳总结短视频平台中“双减”政策信息框架的组织方式,同时分析不同政策信息框架对传播效果的影响;此外,采用在线控制实验法验证了不同政策信息框架对受众采纳意愿的影响。[结论/发现]在短视频平台中有近四成的信息使用了目标框架,其中损失框架居多,多数采用集体主义视角和非叙事陈述方式;目标框架、文化框架、叙事框架对受众的评论、转发、点赞意愿并未产生显著影响;双减政策信息中,损失、收益框架,集体、个人主义价值观以及叙事和非叙事要素都能增强受众的采纳意愿,并且目标框架与文化框架之间存在交互效应。[创新/价值]研究结论对于政策宣传部门及相关政府机构优化政策传播策略,提高传播效果具有启示作用。

“共赢”vs.“牺牲”:道德消费叙述框架对消费者算法推荐信任的影响

消费者在做出道德消费选择时,要面对丰富的道德产品,复杂地权衡功利利益和道德利益。算法决策推荐可以减轻道德消费决策的复杂性,但是消费者在涉及道德伦理的权衡决策中对算法存在不信任,因为算法是一种典型的以功利论来处理道德权衡问题的方式。本研究提出采用“共赢”(vs.“牺牲”)叙述框架对道德消费中的算法推荐信任有积极影响,消费者对功利论式道德观念的接受程度中介了上述积极效应。实验1发现“共赢”(vs.“牺牲”)叙述框架会增加消费者选择算法推荐的意愿。实验2验证了“共赢”(vs.“牺牲”)叙述框架对消费者算法推荐信任的正向影响,以及功利论式道德观念接受度的中介作用。实验3进一步识别了上述影响的边界条件,即道德消费的“共赢”(vs.“牺牲”)叙述框架仅会增强消费者对算法替代型决策推荐的信任,但是并不会改变消费者对于算法增强型决策推荐信任。

框架效应助推铸牢中华民族共同体意识——基于解释水平与心理距离视角

铸牢中华民族共同体意识是新时代民族工作的鲜明主线。由于共同体建设目标的抽象性、个体对目标理解的具体或抽象程度(解释水平)以及目标和个体自我相关的感知(心理距离)会影响个体对共同体建设行为的参与性,因此在不同的框架下,对有关机制的探索将助力如何更好地推动共同体建设。基于促进-防御框架、宏观-微观框架、近端-远端框架三个角度,在心理距离与解释水平双重变量影响下,结合心理阻抗的补偿效应、时间远近对个体感知的影响,研究发现:在心理距离近且解释水平低、心理距离远且解释水平高的项目中,防御框架相较促进框架更能唤起共同体建设意愿;在高解释水平下,宏观框架相较微观框架更易唤起更多的共同体建设行为;在远心理距离、高解释水平下,长时远端框架相较当前近端框架更能唤起个体的共同体建设行为意愿。因此,强调以小事讲小利、以大局讲大义、以具体讲未来、以抽象讲当下的框架方式可以更好推动共同体建设的实践效能。

三水河特大桥桥墩温度场及温度效应研究

为研究温度效应对连续刚构桥空心薄壁墩受力行为的影响,以(98+5×185+98)m变截面预应力混凝土连续刚构桥——三水河特大桥主桥为背景,通过现场温度场测试,研究桥墩垂直温度场和水平温度场的分布规律,并以实测温度场为依据,选取对桥墩刚度影响较大的桥墩高度、顺桥向宽度和壁厚作为关键参数,分析整体均匀温度T和梯度温度ΔT对空心薄壁墩受力的影响。结果表明:实测桥墩垂直温度场随着墩高的变化分布差异较小,水平温度场受日光照射影响较大,桥墩夏季的梯度温度值约为冬季的2倍。墩高对桥墩温度应力的影响基本呈反比关系,顺桥向宽度对墩底温度应力的影响呈线性增长趋势,壁厚与温度应力呈反比关系。对于长联刚构桥,为减小桥墩的温度效应,建议边主墩高度不宜小于60 m,桥墩顺桥向宽度宜尽量减小,桥墩壁厚宜取80~100 cm。

考虑结构空间作用的RC框架梁轴向约束刚度研究

为真实反映结构对框架梁的空间约束作用,提出了轴向约束刚度指标以量化结构空间约束,并建立可模拟框架结构空间约束作用的数值模型。对比足尺框架结构试验数据表明,按规范计算的框架梁抗弯承载力与试验值相对误差为42%~75%,考虑结构轴向约束作用后相对误差缩小至25%以内,说明该模型可较好地模拟框架结构轴向约束作用,验证了该数值模型的合理性和可靠性。在有限元软件SAP2000中建立等效弹性数值模型,通过单参数分析得到对RC框架梁轴向约束刚度有显著影响的关键变量。在常见工程的取值范围内对关键变量进行充分的排列组合,开展规模化数值分析并总结结构空间约束的作用机理与RC框架梁极限状态下轴向约束刚度分布规律,得出了极限状态下RC框架梁轴向约束刚度的计算方法。

框架效应视角下煤矿安全标识有效性影响研究

在煤矿技术致因事故率逐年下降、人因事故率却高居不下的背景下,煤矿安全标识作为安全信息的重要载体,如何影响矿工的安全认知和决策过程成为信息时代重要的研究内容。为探索安全标识有效性影响机理,降低煤矿安全事故发生概率,结合框架效应,借助ErgoLAB Experiment平台和Tobii Pro Nano眼动仪收集了30名被试的试验数据,研究在不同作业情境(高风险或低风险)下,不同损益框架的煤矿安全标识对矿工再认记忆任务和眼动行为的影响。结果表明:高风险作业情境及使用损失框架展示的安全标识能显著提高被试的再认记忆正确率;在低风险作业情境的安全标识设计中,可以突出潜在风险和损失,以吸引矿工有限的安全注意力。研究结果可为安全标识优化设计提供证据和参考,有助于提高煤矿的安全生产水平。

SNARC效应的空间参照机制

SNARC效应是人脑处理和解释数字信息时,数字信息与空间属性产生的一种联结现象。该效应自被发现以来,就成为认知心理学的研究热点之一。然而,关于该效应产生的空间机制仍存在争议。从SNARC效应的自我空间参照和非自我空间参照两个角度进行梳理,并基于空间参照的层级系统和内外系统两种假设,深入分析SNARC效应空间参照的组织系统。未来可在深入探讨SNARC效应在垂直方向上的空间参照机制和组织系统的基础上,进一步研究SNARC效应在水平与垂直两个方向的空间参照行为与神经机制的特点及相互关系。

New tangent stiffness matrix for geometrically nonlinear analysis of space frames

A three-dimensional beam element is derived based on the principle of stationary total potential energy for geometrically nonlinear analysis of space frames. A new tangent stiffness matrix, which allows for high order effects of element deformations, replaces the conventional incremental secant stiffness matrix. Two deformation stiffness matrices due to the variation of axial force and bending moments are included in the tangent stiffness. They are functions of element deformations and incorporate the coupling among axial, lateral and torsional deformations. A correction matrix is added to the tangent stiffness matrix to make displacement derivatives equivalent to the commutative rotational degrees of freedom. Numerical examples show that the proposed dement is accurate and efficient in predicting the nonlinear behavior, such as axial-torsional and flexural-torsional buckling, of space frames even when fewer elements are used to model a member.