Finite element modeling assumptions impact on seismic response demands of MRF-buildings

Recent seismic events have raised concerns over the safety and vulnerability of reinforced concrete moment resisting frame ＂RC-MRF＂ buildings. The seismic response of such buildings is greatly dependent on the computational tools used and the inherent assumptions in the modelling process. Thus, it is essential to investigate the sensitivity of the response demands to the corresponding modelling assumption. Many parameters and assumptions are justified to generate effective structural finite element（FE） models of buildings to simulate lateral behaviour and evaluate seismic design demands. As such, the present study focuses on the development of reliable FE models with various levels of refinement. The effects of the FE modelling assumptions on the seismic response demands on the design of buildings are investigated. the predictive ability of a FE model is tied to the accuracy of numerical analysis; a numerical analysis is performed for a series of symmetric buildings in active seismic zones. The results of the seismic response demands are presented in a comparative format to confirm drift and strength limits requirements. A proposed model is formulated based on a simplified modeling approach, where the most refined model is used to calibrate the simplified model.

Study of Suitability of Out-of-Codes Tall Slab-Column and Shearwall Structure

The purpose of this paper is to discuss the suitability of out-of-codes tall slab-column and shearwall structure and to popularize the structure in seismic region.In the research,flat-plate floor was used in slab-column and shearwall structure in the practical engineering,the key parameters of slab-column and shearwall structure and frame-shearwall structure such as deflection,punching shear behavior,story drift and capability curve were worked out by static plastic analysis,elastic-plastic time history analysis and pushover analysis,then the suitability of out-of-codes tall slab-column and shearwall structure was evaluated.The results show that the out-of-codes tall slab-column and shearwall structure studies could satisfy the require of deflection and punching shear behavior,the story drift under 7 degree expected rare earthquake waves could satisfy the limit value in the codes and the seismic design spectrum was crossed by the capability curve of the structure and the structure could not collapse.The conclusion is that slab-column and shearwall structure with reasonable design built in Ⅱ soil site of intensity 7 seismic fortification zone can be designed higher than the limit height in the codes.

环境法典污染控制制度的二元结构与体系整合

污染控制制度是环境法典的最主要内容,需要在现行污染防治单行法律法规的基础上进行体系化整合。现行立法分为两大基本类型,环境要素污染防治法围绕环境要素的污染排除进行制度设计,污染物质和能量污染防治法围绕污染物质和能量的减量和管制进行制度设计。在整合进入环境法典污染控制编时,两类污染防治制度的共通性制度要提炼出来进入污染控制编的基本规定,环境要素污染控制制度仍然围绕水、海洋、大气、土壤的污染控制展开,规定与环境要素相对应的具体污染控制制度。污染物质控制制度包括固体废物污染控制、有毒有害物质污染控制和放射性污染控制几个方面,应规定污染物质的全过程管控制度。能量污染控制制度以噪声污染控制为重心,振动、电磁辐射和光辐射污染控制应在法典中有基本规定。在协调不同类型污染控制制度的基础上,对现行污染防治规定进行归类、精简、合并、调整,并补充重要的污染控制规则,以完成环境法典污染控制编的制度设计和编排。

Improved design of special boundary elements for T-shaped reinforced concrete walls

This study examines the design provisions of the Chinese GB 50011-2010 code for seismic design of buildings for the special boundary elements of T-shaped reinforced concrete walls and proposes an improved design method. Comparison of the design provisions of the GB 50011-2010 code and those of the American code ACI 318-14 indicates a possible deficiency in the T-shaped wall design provisions in GB 50011-2010. A case study of a typical T-shaped wall designed in accordance with GB 50011-2010 also indicates the insufficient extent of the boundary element at the non-flange end and overly conservative design of the flange end boundary element. Improved designs for special boundary elements ofT-shaped walls are developed using a displacement-based method. The proposed design formulas produce a longer boundary element at the non-flange end and a shorter boundary element at the flange end, relative to those of the GB 50011-2010 provisions. Extensive numerical analysis indicates that T-shaped walls designed using the proposed formulas develop inelastic drift of 0.01 for both cases of the flange in compression and in tension.

考虑消落带岩体劣化影响的典型危岩岸坡稳定性研究

三峡库区周期性水位升降引起的消落带岩体劣化对典型危岩岸坡稳定性具有重大影响。基于野外调研及地勘资料,采用通用离散单元法程序(universal distinct element code,简称UDEC)研究了消落带劣化区形态对近水平层状高陡危岩岸坡的稳定性影响。研究表明:目前三峡库区巫山段的近水平层状危岩岸坡消落带岩体劣化严重,在不同消落带劣化区存在紧密层状、松散碎裂状、溶蚀凹腔状、含挤压碎裂带等典型消落带劣化区形态;含有第1种消落带劣化区形态的危岩岸坡稳定性较好,危岩体位移较小,失稳模式为滑移破坏;含有第2种消落带劣化区形态的危岩岸坡危岩体先向坡内偏移,其后随着消落带岩体支撑强度弱化向坡外倾倒破坏;含有第3种消落带劣化区形态的危岩岸坡危岩体向坡外位移较大,失稳模式为倾倒破坏;含有第4种消落带劣化区形态的危岩岸坡稳定性主要受挤压破碎带的力学性质控制,易产生沿破碎带切割面的旋转滑移破坏;通过对以上4种劣化区形态的危岩岸坡增加防治加固措施,危岩体的变形位移得到了不同程度的有效控制。

Investigating Earth Reaction to Pull-Out Process of Frictional Rock Bolts Using Distinct Element Method

The reaction of earth to pull-out process of frictional rock bolts was here modeled by the distinct element method (DEM). Ten frictional bolts were prepared;the expanding shells of five bolts included convex edges and the others had the shells with concave bits. The strength of bolts was measured by applying a standard pull-out test;the results confirmed that the strength of shells with convex edges was remarkably more than the strength of other shells. Furthermore, a two-dimensional DEM model of the test was developed by a particle flow code;the obtained results showed that the reaction of rock particles to the contacts occurring between the convex edges and earth was considerably more than those of the concave bits. In the other words, the convex edges transferred the pull-out force into a large area of the surrounded rock, causing these bolts to have the highest resistance against earth movements.

基于Barker码脉冲压缩技术的钢板多阵元Lamb波电磁超声换能器设计与优化

为了解决传统Barker码脉冲压缩技术受脉冲功率放大器额定参数(占空比,最大脉冲宽度等)限制而导致的脉冲压缩效果下降、检测速度降低等问题,提出一种基于Barker码脉冲压缩技术的多阵元Lamb波电磁超声换能器(EMAT)。建立了基于tone-burst信号激励-Barker码脉冲压缩技术的多阵元Lamb波EMAT检测过程的有限元模型,分析了永磁体的配置形式、阵元序列长度、激励信号周期数、曲折线圈匝数等因素对脉冲压缩后的主旁瓣比和主瓣宽度的影响,并进行了实验验证。结果表明:曲折线圈匝数为4和Barker码序列长度为13位的多阵元EMAT在配置3对外置永磁体后,其信噪比(SNR)可提高9.8 dB。综合考虑检测回波的空间分辨率和SNR,多阵元Lamb波EMAT最佳参数为:曲折线圈匝数为10、激励信号周期数为11、Barker序列为13位,并配置3对外置永磁体。

钠冷快堆燃料元件性能分析程序的开发与验证

为了评估钠冷快堆氧化物燃料元件稳态、瞬态和事故条件下的性能和行为演化,开发了钠冷快堆燃料元件性能分析程序FIBER。程序采用有限体积法实现燃料元件温度的计算,用有限元方法实现力学、裂变气体释放的计算,并通过时间步长控制模块控制程序的稳定运行。为验证程序的准确性,通过调研得到俄罗斯BN600反应堆辐照数据,与FIBER程序的裂变气体释放、柱状晶粒等计算结果进行对比分析。结果表明,FIBER程序对最大燃耗11.8at%、最大辐照损伤78 dpa的快堆燃料元件的辐照变形、柱状晶区、裂变气体释放性能评价是有效的。

卫生健康信息数据元标准2023版和2011版比较研究

目的/意义对比分析卫生健康信息数据元标准2023版和2011版,探讨差异与改进之处,以期为标准的更新与实施提供有益的参考和指导。方法/过程整理对比2023版较2011版卫生健康信息数据元标准的更新内容,分析总结修订对标准化程度、规范化水平以及数据完整性和准确性等方面的提升作用。结果/结论2023版在数据完整性和规范化等方面实现显著提升。分析2023版标准在实施过程中可能面临的挑战和问题,提出针对性建议和对策。

民法典彰显社会主义核心价值观法治元素探析

为了探究社会主义核心价值观法治元素在民法典中的体现,围绕民法典司法解释的立法诠释、民法典融入法治建设的重大成果以及民法典彰显社会主义核心价值观法治元素等多个方面,研究民法典的基本解释、概念解释、体系解释、目的解释和价值解释,揭示社会主义核心价值观法治元素在民法典中的深刻内涵和实践要求。研究表明,民法典以其系统化、综合性的法律规范,将社会主义核心价值观贯穿始终,使其成为民事主体行为的指导原则和社会发展的内在动力,在推进社会主义法治建设、保障公民合法权益方面发挥着重要作用。

Numerical and theoretical study of large-scale failure of strata overlying sublevel caving mines with steeply dipping discontinuities

The deformation and fracture evolution mechanisms of the strata overlying mines mined using sublevel caving were studied via numerical simulations.Moreover,an expression for the normal force acting on the side face of a steeply dipping superimposed cantilever beam in the surrounding rock was deduced based on limit equilibrium theory.The results show the following:(1)surface displacement above metal mines with steeply dipping discontinuities shows significant step characteristics,and(2)the behavior of the strata as they fail exhibits superimposition characteristics.Generally,failure first occurs in certain superimposed strata slightly far from the goaf.Subsequently,with the constant downward excavation of the orebody,the superimposed strata become damaged both upwards away from and downwards toward the goaf.This process continues until the deep part of the steeply dipping superimposed strata forms a large-scale deep fracture plane that connects with the goaf.The deep fracture plane generally makes an angle of 12°-20°with the normal to the steeply dipping discontinuities.The effect of the constant outward transfer of strata movement due to the constant outward failure of the superimposed strata in the metal mines with steeply dipping discontinuities causes the scope of the strata movement in these mines to be larger than expected.The strata in the metal mines with steeply dipping discontinuities mainly show flexural toppling failure.However,the steeply dipping structural strata near the goaf mainly exhibit shear slipping failure,in which case the mechanical model used to describe them can be simplified by treating them as steeply dipping superimposed cantilever beams.By taking the steeply dipping superimposed cantilever beam that first experiences failure as the key stratum,the failure scope of the strata(and criteria for the stability of metal mines with steeply dipping discontinuities mined using sublevel caving)can be obtained via iterative computations from the key stratum,moving downward toward and upwards away from the goaf.

法学课程融入思政元素的路径探究——以民法学教育为例

作为高校课程思政建设的重要组成部分,法学课程思政建设的思政目标是将专业知识和思政元素有机融合,以立德树人为根本,培养全面发展的德法兼修的法治人才。在民法学课程的教学中融入思政元素,有助于培养学生的公民意识及社会责任感,达到“内化于心,外化于行”的课程思政育人效果。将思政元素融入民法学课程教学的具体路径主要包括:明确民法学课程的思政目标,融合民法学课程专业知识和思政内容,变革民法学课程思政授课方法,以及将民法学课程思政元素融入实践环节等。

岩土球形颗粒体粒间接触力学特性及接触模型验证

针对大理岩和花岗岩两种材料,分别进行了球颗粒法向、切向接触力学试验;以大理岩为例,总结了非线性接触模型及其参数,并进行了球颗粒集合体的离心模型试验,通过数值模拟和试验结果的对比验证了接触模型及其参数的合理性。研究结果表明:颗粒法向接触以脆性断裂为破坏形态,切向接触以摩擦侵蚀为破坏特征;法向、切向刚度曲线都可以利用幂函数进行拟合;利用非线性接触模型及其参数可以有效模拟颗粒集合体的力学性状,同时还能够反映散体模型细部的离散变形特征。

硒、铁、锌和铜对动物健康的影响及其对表观遗传调控机制的研究进展

微量矿物元素(微量元素)少量存在于动物机体中,但对机体生理功能至关重要。研究证明,微量元素通过表观遗传调控对动物机体产生影响,起到提高动物生产力、防治动物疾病的作用,可降低饲养成本、提高动物产品(肉、蛋和奶等)质量。表观遗传学的定义为不依赖于DNA序列变化而导致染色体变化的、可遗传基因表达变化的现象和机制,是近年来研究的一大热点,其调控机制包括DNA甲基化、组蛋白修饰和非编码RNA调控等。本文主要论述常见的几种微量元素硒、铁、锌和铜对动物健康的影响及其表观遗传的调控作用和机制,以期为之后的研究和应用提供一定参考。

平面矩形单元及其在结构拓扑优化中的应用

在结构拓扑优化研究领域,越来越多的研究提供了简短的程序代码以验证所提方法或算法的有效性,其中应用较多的单元是平面矩形单元或更为特殊的正方形单元,但其解析公式均没有明确给出。基于此,本文以在结构拓扑优化中惯常使用的矩形单元为研究对象,推导其单元刚度矩阵、单元应力矩阵和单元质量矩阵的解析表达式,采用Matlab软件编写相关矩阵的计算代码,并通过结构拓扑优化方面的应用算例对代码进行了验证。结果表明,所给出的代码可直接使用,给出的单元矩阵的解析公式有助于更好地理解和使用相关结构拓扑优化程序。

移动互联网背景下大学物理实验课程教学资源库的建设与实践

以X射线晶体衍射实验为例,利用二维码技术,将有关实验原理、课程思政、实验内容,仪器使用方法构成的教学资源库部署于云端。在移动互联网条件下,学生能很便捷地利用手机微信或支付宝扫一扫功能,在预习、实验操作和课后各阶段查询大学物理实验课程的教学资源库,促进了主动性学习。匿名问卷调查结果表明所建设的教学资源库得到大多数学生的认可,并被建议向其他课程进行推广。

基于离散元法的三轴试验数值仿真分析

基于离散元法的思想,利用Fish语言编写程序在PFC软件上实现了三轴试验的数值模拟。实现了土体细观参数和宏观参数的标定,对于内摩擦角2°-30°的土体,可以从文章的数值模拟结果中找到大致对应的细观参数。得出细观摩擦系数、法向粘结强度和切向粘结强度等细观参数会影响应变的峰值强度与宏观内摩擦角和粘结力,细观摩擦系数与内摩擦角成正相关,与粘结力成负相关。根据数值模拟的结果,提出粘结力与细观摩擦系数关系公式和内摩擦角与细观摩擦系数关系公式,利用室内试验结果验证了拟合公式的准确性和可行性。

企业跨越边界的数字化管理:基于希音(SHEIN)公司的案例研究

衡量企业数字化转型是否成功的两个显著标志为是否真正以客户为中心和数据驱动,而对企业的供应链、其他相关企业和消费者进行有效管理是实现企业数字化转型的关键。着眼于数字经济形态下企业边界与企业价值两方面问题,以广州希音(SHEIN)公司为案例,采用扎根理论的编码方法,基于实地调研的一二手资料,探索数字经济条件下企业跨越组织边界增加价值源泉的管理方式。研究发现:在数字经济条件下,基于技术、模式、管理的集成应用,全过程、全环节数据管理综合运用构成的跨越边界的数字化管理模式是企业制胜的法宝。其中,企业及其供应链成员、消费者、数据构成数字生态,生态内各主体的价值创造构成企业价值源泉;供应链成员生产、长尾市场客户需求和数据要素力量成为企业新增价值源泉。希音公司依靠现代信息技术和中小企业生产能力、高效物流体系、数据连通消费者介入的全方位支撑和集成应用而形成的跨边界的数字化价值管理模式,以分布式生产、集中式管理的数字化管理模式开展供应链成员价值管理,以数据连通的全链路数字化管理模式对生产端和市场端进行价值管理,以快速生产、快速销售的全产品数字化管理模式对市场需求价值和消费者价值进行管理。可见,数字技术通过改变企业的生产和管理结构以及市场结果从而延伸了企业能力、扩大企业边界,数据要素给供应生态带来了深度影响。以数字化方式统合供应链并进行管理的创新模式为其他跨境电商企业提供了借鉴可能。

多物质流体动力学方法与结构动力学方法结合的流固耦合计算技术

建立一种基于重叠网格空间覆盖判断的流固耦合计算技术,把流场计算的Euler多物质流体动力学计算过程和Lagrange结构动力学计算过程相结合以描述流固间的相互作用.介绍该计算技术的具体实现过程,讨论提高几何判断效率、避免耦合遗漏、流固计算时间步协调等处理技术.应用建立的流固耦合计算程序模拟爆炸容器中爆炸流场对容器内部结构、容器壳体的作用过程.计算结果表明其可以反映流场发展过程、流场结构相互作用和结构的运动变形和破坏过程.

关于网络隐私保护的数字信息加密技术

针对当前循环编码加密算法的防破译能力不高的问题,提出基于同态码元频数检测的网络隐私保护数字信息加密技术。首先进行网络隐私保护对象的数字信息加密密钥构造,然后进行加密和解密的编码设计,采用同态码元频数检测进行数字加密的密钥优化,提高防破译水平,最后进行仿真实验。结果表明,采用该数字信息加密技术,加密深度较高,加密数据的破译率得到有效控制,性能优于传统方法,有效保障了网络隐私保护。