大跨度斜拉桥施工过程中几何非线性影响

本文的施工过程仿真对象为国内巢座大跨度斜拉桥平面杆系摸型,利用有限元程序SAP2000对其按照施工步骤,进行前进分析。仿真过程中,计入三种几何非线性影响因素,包括拉索垂度引起的非线性效应、梁柱效应、大位移影响.对三者在施工中各自的影响作出比较。     

浅谈大跨度斜拉桥施工过程中的风险分析与对策

进入21世纪随着我国国民经济的显著提升,我国的交通运输建设事业也取得了较大的进步,桥梁是我国的交通建筑方面的重要组成部分,科技和电子计算机技术大力发展并被广泛使用于各项领域中,在我国的桥梁工程建设施工中也得以运用,大跨度的斜拉桥的建设也提上日程,本文以大跨度斜拉桥在施工过程中的施工风险为主要研究对象,对桥梁施工过程中的风险加以分析,并在此基础上提出针对性的风险应对措施与建议。     

大跨度混凝土斜拉桥施工控制

结合上地斜拉桥的实际情况,提出了上地斜拉桥施工控制目标、施工控制内容、具体的施工控制方法和施工控制精度等施工监控方案。本文利用有限元软件MIDAS对上地斜拉桥建立了平面分析模型,进行了拉索施工阶段计算,从而确定斜拉索一张及二张力,随着施工工期的进行,调整了拉索张拉次序及时间,保证了整桥在拉索张拉施工过程中的安全。     

大跨度无粘结预应力板局部支撑施工技术

近些年来,大跨度的建筑物逐渐进入人们的生活,很多商场、广场、图书馆、展厅等大多采用这种大跨度无粘结的预应力结构形式。大跨度的预应力施工可以最大限度的对整体受力情况进行平衡,令其达到一定的设计标准。本文主要是从大跨度的无粘结预应力结构支撑技术入手,对其材料、管理、维护等方面进行了阐述,形成了大量的分析数据和科学手段,供同行参考。     

转体斜拉桥重心计算的实用方法

提出采用CAD法和有限元法计算桥梁重心,计算简便且结果准确.以绥芬河斜拉桥为例,给出该桥的理论偏心距为1.3cm.     

一斜拉桥锚拉板式索梁锚固结构有限元分析

目前,国内外修建的许多大跨度钢斜拉桥都把锚固结构作为设计的重点之一,索梁锚固区受力十分复杂;对锚拉板式索梁锚固结构在最不利工况下有限元分析,得出锚拉板应力分布情况,为类似结构的设计提供了的参考。     

厚壁受压元件的有限元建模研究

在对厚壁受压元件进行分析和研究时由于壁厚较大,与薄壁受压元件的分析方法不同,应力沿壁厚分布数值相差较大。在对这类结构进行有限元建模时一般采用实体单元来模拟。下面结合经典力学算法和有限元算法加以对比研究,从而获得在对厚壁件进行有限元分析时可以采用的优质模型。     

大跨度桥梁抗震分析中的有限元方法

从有限元角度和工程抗震角度,分析了大跨度桥梁有限元模拟中的基本概念和关键问题,着重于工程的实际可操作性和细节的处理,最后指出需要注意的问题。     

基于MRIO模型与LMDI方法的中国水产品贸易隐含碳排放转移研究

随着国际贸易强度的日益增加,隐含碳排放呈现不断增长趋势,国际贸易已成为隐含碳排放转移的重要方式。本文利用MRIO模型测算中国2005—2014年水产品贸易隐含碳排放转移量,并采用LMDI方法进行效应分解,从规模效应、结构效应及强度效应三方面研究水产品贸易发展对隐含碳排放转移的驱动影响。结果表明,中国水产品贸易隐含碳排放转移量总体呈先降后升特征,且始终为水产品贸易隐含碳排放净流出国。规模效应在水产品进出口贸易隐含碳排放表现拉动作用,而结构效应和强度效应对水产品贸易隐含碳排放进出口则具有抑制作用。因此,通过大力发展渔业低碳技术和提高渔业生态效率降低水产品贸易隐含碳排放强度、构建整体海洋生态系统、优化水产品贸易结构,是减少中国水产品贸易隐含碳排放并提升中国在国际气候谈判中话语权的重要举措。     

Design and modeling of the CVT for adjustable inerter

In this paper we investigate an inerter equipped with a prototype continuously variable transmission (CVT) designed for the novel tuned mass damper. Inerter enables stepless changes of inertance via varying transmission ratio of the CVT. The main difference from classical inerter is addition of CVT, hence we present its design and properties in details. Motion of the proposed CVT is oscillatory and we test it for the actual working conditions. We derive the mathematical model of the system that include dissipation via dry friction. We analyse the actual transmission ratio, internal motion resistances and identify the inertia of CVT components using energy conservation method and validate further. Finally, we apply actual working conditions and compare the experimental and numerical exciting torques of the CVT. We obtain good agreement between them, hence the proposed model is robust and gives reliable results.     

Coupled matrix factorization and topic modeling for aspect mining

Aspect mining, which aims to extract ad hoc aspects from online reviews and predict rating or opinion on each aspect, can satisfy the personalized needs for evaluation of specific aspect on product quality. Recently, with the increase of related research, how to effectively integrate rating and review information has become the key issue for addressing this problem. Considering that matrix factorization is an effective tool for rating prediction and topic modeling is widely used for review processing, it is a natural idea to combine matrix factorization and topic modeling for aspect mining (or called aspect rating prediction). However, this idea faces several challenges on how to address suitable sharing factors, scale mismatch, and dependency relation of rating and review information. In this paper, we propose a novel model to effectively integrate Matrix factorization and Topic modeling for Aspect rating prediction (MaToAsp). To overcome the above challenges and ensure the performance, MaToAsp employs items as the sharing factors to combine matrix factorization and topic modeling, and introduces an interpretive preference probability to eliminate scale mismatch. In the hybrid model, we establish a dependency relation from ratings to sentiment terms in phrases. The experiments on two real datasets including Chinese Dianping and English Tripadvisor prove that MaToAsp not only obtains reasonable aspect identification but also achieves the best aspect rating prediction performance, compared to recent representative baselines.     

Microstructured multi-well plate for three-dimensional packed cell seeding and hepatocyte cell culture

In this article, we present a microstructured multi-well plate for enabling three-dimensional (3D) high density seeding and culture of cells through the use of a standard laboratory centrifuge to promote and maintain 3D tissue-like cellular morphology and cell-specific functionality in vitro without the addition of animal derived or synthetic matrices or coagulants. Each well has microfeatures on the bottom that are comprised of a series of ditches/open microchannels. The dimensions of the microchannels promote and maintain 3D tissue-like cellular morphology and cell-specific functionality in vitro. After cell seeding with a standard pipette, the microstructured multi-well plates were centrifuged to tightly pack cells inside the ditches in order to enhance cell-cell interactions and induce formation of 3D cellular structures during cell culture. Cell-cell interactions were optimized based on cell packing by considering dimensions of the ditches/open microchannels, orientation of the microstructured multi-well plate during centrifugation, cell seeding density, and the centrifugal force and time. With the optimized cell packing conditions, we demonstrated that after 7 days of cell culture, primary human hepatocytes adhered tightly together to form cord-like structures that resembled 3D tissue-like cellular architecture. Importantly, cell membrane polarity was restored without the addition of animal derived or synthetic matrices or coagulants.     

大科学工程组织管理模式对比分析及对我国的启示

运用案例分析法和对比分析法,将大科学工程组织管理模式系统归类和分析,并选取美日发达国家及我国典型大科学工程案例,从适用条件、领导主体、结构效率和整体性对其进行综合对比。同时结合各国大科学工程组织实施的宏观科技环境,分析在当前形势下我国如何合理借鉴国外大科学工程组织管理模式,为进一步提升我国大科学工程组织管理能力提出建议。     

面向可适应性的产品平台功能需求建模与分析

为增强大规模定制下产品族设计的适应性能力,基于客户需求分析,对产品的功能要求进行分析并将其分成三类,结合公理设计和通用设计理论,以元模型描述产品的功能结构概念,提出了一种面向可适应性的产品平台功能需求建模与分析方法。将客户对产品的需求转化为产品功能要求,形成功能概念空间,选择相应的结构概念,并将其组合成结构概念空间。然后根据功能-结构映射,建立并重排设计矩阵,通过对功能要求与设计参数对应关系及敏感性分析,确定产品平台各类型设计参数。最后以电力液压盘式制动器实例来阐述产品平台功能需求建模与分析过程。