地铁环境振动预测中链式结构振级落差灵敏度分析

针对地铁环境振动预测中使用的链式结构力学简化模型,利用灵敏度分析对链式结构中各参数变化对各振级落差影响规律进行系统研究;推导给出振级落差一阶灵敏度解析表达式和一种逆矩阵偏导数求解方法;并提出利用自由衰减时域段实测数据逆求链式结构中各力学参数方法。研究结果表明:通过灵敏度分析可以确定链式结构中任一力学参数改变对其任一层振级落差影响程度,找出对系统动态响应影响较大的环节。该方法有助于提高环境振动预测精度。     

Remaining fatigue life assessment of corroded mooring chains using crack growth modelling

Failures caused by the combined actions of fatigue, corrosion and wear are important safety concerns for mooring chains used on floating structures in the oil and gas industry. Prediction of remaining corrosion fatigue life based on surface condition could therefore be a useful tool for the continued safe operation of corroded chains. This paper investigates the use of crack growth modelling for estimating the remaining corrosion fatigue life of mooring chains that exhibit significant pitting corrosion damage. A crack growth modelling approach is used to produce remaining fatigue life estimates for a selection of severely pitted mooring chains. Using fatigue crack growth rate test results for grade R4 high strength mooring chain steel, empirical crack growth laws are presented for free corrosion and cathodic protection conditions at load ratio R = 0.1. Two different methods for establishing equivalent cracks from surface scans of corrosion damage are presented. The mooring chains are proof loaded as part of their manufacturing process. Residual stresses introduced during this process have therefore been determined by finite element analysis and accounted for in the fatigue crack growth predictions. One of the equivalent crack models, accounting for the single dominant corrosion pit, provided quite accurate fatigue life predictions when compared with full scale test results.     

企业物流管理中的战略规划

本着重从企业物流管理战略目标的设定、竞争战略的定位、物流系统发展战略的制定等方面讨论了企业物流管理中的战略规划问题,研究了企业如何制定出合适的物流战略规划,为企业带来真正的竞争优势。     

HBeAg特异免疫复合物检测及临床意义

采用单克隆抗－ＨＢｅ固相ＥＬＩＳＡ法检测１１８例ＨＢＶ感染者血清中ＨＢｅＡｇ特异免疫复合物（ＨＢｅＡｇ／ＩＣ）,结果表明∶ＨＢｅＡｇ／ＩＣ与ＨＢＶ复制相关,可作为ＨＢＶ复制的一种血清学标志,ＨＢｅＡｇ阴性、ＨＢＶＤＮＡ阳性者中,６２．２％患者ＨＢｅＡｇ／ＩＣ阳性,提示ＨＢｅＡｇ／ＩＣ的形成致使夹心法不能检出ＨＢｅＡｇ,这类患者仍可以是ＨＢＶ野毒株感染,并非均为ＨＢｅＡｇ缺陷变异株感染;ＨＢｅＡｇ／ＩＣ阳性血清ＡＬＴ异常率明显高于ＨＢｅＡｇ／ＩＣ阴性血清（Ｐ＜０．０１）,提示ＨＢｅＡｇ／ＩＣ存在与肝损伤有关。     

北京市轨道交通产业化研究

分析北京城市轨道交通产业的特点,阐述其发展的优劣势,从规划设计咨询类、工程建设施工类、装备制造类、运营类及增值服务类等5个方面,分析北京城市轨道交通产业链的构成与发展情况及发展需求,并结合国家对轨道交通的战略性新型产业的定位,提出3点发展建议,为推动北京城市轨道交通产业的健康发展提供参考.     

基于交通因子状态网络的城市交叉口交通流预测

信息技术的快速发展,为交通研究和城市交通管理提供了大规模、多样化的数据资源,并为城市交通状态估计和交通流预测方法的研究提供了有力支持.将城市交叉口视为一个微观交通系统,采用数据驱动与领域知识结合的方式,建立微观层次的交通因子状态网络模型(Traffic Factor State Network,TFSN),考察交通因素...     

Achieving sustainable development of supply chain by incorporating various carbon regulatory mechanisms

Nowadays, sustainability issues have received considerable attention in supply chain management because of the governmental requirements as well as expectations of the people. This paper introduces a novel supply chain network design problem to cover three dimensions of sustainability, namely economic, environmental, and social. The advantage of the presented model stems from considering the booming development aligned with reduction in environmental impact. In this paper, to achieve the mentioned benefits and to derive a more sustainable supply chain, a novel model in the presence of the most commonly used carbon policies is proposed. This paper, addresses sustainable development through imposing proper carbon regulatory mechanisms. Main contribution of this study is to consider the effect of imposing carbon policies on environmental advantages as well as improving the regional development level in a supply chain network design problem. Moreover, the shipment consolidation decisions are utilized to reduce cost as well as environmental impact. In addition, a novel mixed uncertainty approach is proposed to capture the uncertain emission parameters. The numerical examples and a case study are analyzed to evaluate the performance of the proposed models. It is concluded that, a high-growth economy with low-carbon can be made and also almost global well-being of people is ensured by applying the proposed model. Some managerial insights are provided for the enterprises of supply chains to make the most appropriate sustainable decisions. Finally, proper carbon emission policies are suggested based on the region sustainability characteristics.     

开放式零件库TDB的一种实现方法

对零件库进行了介绍，主要研究了临时数据库(TDB)的功能，提出了在FORTRAN语言联编和UG／GRIP语言映射过程中，运用组结构实现TDB的功能，其具体操作是运用链表来实现对临时几何实体的操作，即实现临时几何实体的删除、组实体的转化等操作；将符合ISO13584．31标准的FORTRAN联编程序文件，通过用C语言编写的转换接口的编译，最终生成Unigraphics系统下的GRIP语言程序．     

锚索预应力损失的影响因素及对策

在高速公路建设中，预应力锚索桩和预应力锚索框架地梁越来越多地出现在高边坡工程中。文章就锚索预应力损失的影响因素及减小预应力损失的方法进行探讨。     

定型包装食品商品标志存在的问题

食品商品标志是卫生监督中进行标志裁决的依据 ,我国《食品卫生法》对此有明确规定。在日常卫生监督中 ,经常发现一些定型包装食品的商品标志存在标注内容不规范 ,夸大、虚假 ,缺少主要事项 ,易于清除、涂改或变更 ,标注不清晰、不易辨识等问题 ,给食品卫生安全带来严重隐患。为保证食品商品标志的正确标注 ,应进一步抓好食品生产经营者自律、消费者监督和卫生监督 3个环节。