论述壁面剪应力在提高固井水泥浆顶替效率的研究

固井工程是一项应用工程,是建井过程中的重要环节,它直接影响钻井周期和建井成本,以及油田开发方案的实施。深井、超深井的井下地质条件非常复杂,对固井质量有许多不利的因素,在井下条件确定的情况下,决定性的因素是环空流动的壁面剪应力,它是影响顶替效率的主要因素。     

铁路桥连续刚构边跨现浇段的吊架设计及受力检算

采用挂篮施工的连续刚构边跨现浇段的支架形式多种多样,其设计目的是施工简便、安全牢固、确保质量及节约成本。在遂渝二线铁路薛家坝涪江左线特大桥连续刚构梁边跨现浇段施工时采用型钢吊架支撑,吊架分别利用原施工悬浇节段的挂篮及在墩顶预埋工字钢作支承点。吊架施工现浇段不仅结构简单、施工方便,而且在安全、质量及效益方面均取得了很好的效果。文章对型钢吊架的设计、施工方法进行了详细介绍,并对吊架进行了受力分析及验算,验证了方案的可行性,为以后同类桥型的施工提供参考。     

工程建设中的混凝土裂缝控制与处理

建设工程中的混凝土裂缝控制是一项复杂的工作,需要材料、设计、施工等方面的相互协调、共同配合。在各个环节采取严密的措施,混凝土裂缝是可以得到有效控制的。文章结合工程实践,分析了混凝土工程中常见裂缝的产生原因,提出了混凝土施工中应注意的事项,以完善混凝土施工工艺,避免混凝土产生裂缝,从而保证建筑工程的质量,延长建筑物的使用寿命。     

Development of the ‘Travelcard’ Concept in Urban Public Transport

Traditionally, urban bus operators have collected fares in cash for each trip. Some limited mechanisation has occurred in ticket issue at stations. Partly for reasons of operating convenience, there has recently been a shift to simpler fares and prepayment, notably through the introduction of ‘Travelcards', that is, tickets or passes permitting unlimited use of the network (or zones thereof) for a defined period. These cover both all-bus systems, and bus/rail networks (such as the West Midlands PTE system). They are now used in all main British conurbations, following introduction of the London Transport bus/rail Travelcard in May 1983. The Travelcard in effect redefines the ‘product’ being sold. Instead of the public transport service being perceived as a series of separate journeys, payment is made periodically for use of the network as a whole. Cost perception is thus put on a similar basis to that for the private car. The marginal money cost for each trip becomes zero. Interchange penalties associated with re-booking are eliminated. Payment may be made by cheque or credit card, rather than cash, further changing the perception of costs. Product quality is also enhanced through speeding up of services (one-person- operated buses), and enabling the user to select the quickest and/or most convenient route in a network by removing the interchange penalty.     

The relationships between stress,health, and physically active leisure as a function of life‐cycle

This article examines relationships between stress, health, and participation in physically active leisure using data collected as part of the 1985 and 1990 U.S. National Health Interview Surveys (NHIS). In particular, the article analyzes: (a) the effects of life‐cycle progression (controlled for gender) on subjectively perceived stress and self‐reported health; (b) the role of physically active leisure in enhancing health or buffering adverse health outcomes of stress; and (c) the effects of selected social‐economic factors, such as education and income, on the relationships between life‐cycle, stress, health, and physically active leisure. According to our analyses: (1) stress is unevenly distributed across the life span; (2) stress‐reducing effects of physically active leisure are present among retired older people more so than in the middle‐aged life‐cycle groups; and (3) direct health‐enhancing effects of participation in physically active leisure are more evident than the buffering effects of leisure on stress‐health relationships. A critical discussion of methodological and substantive issues facing researchers interested in the relationships between leisure, stress, and health is provided.     

某校行政办公楼预应力砼梁施工方案

在进行预应力砼梁施工时,施工用材要符合设计要求,设备满足施工要求。文章从设备、配件的安装检查,预应力钢绞线的安装、锚固、张拉应力的控制及施工技术要点,砼梁的浇筑及灌浆养护,安全文明施工、环境要求及工程资料的整理等方面对预应力砼梁施工进行了探讨。     

Challenging The Spirit Level: Is There Really a Relationship between Inequality and Obesity?

This paper examines the proposition, set out in The Spirit Level, that inequality is associated with high levels of obesity. It reviews existing literature and uses British Household Panel Survey data to study how district‐level and regional‐level income inequality is related to obesity in the UK. This is likely to be the first study of its type that uses individual‐level data that is representative of the UK population. We find little evidence to support policies that reduce income inequality with the aim of reducing obesity levels in the UK.     

开敞式泄水闸稳定应力计算

对某开敞式泄水闸进行了整体抗滑稳定和基底应力计算,计算结果表明泄水闸的结构布置是合理的。     

预制桩填土复合地基的设计与施工

论述了小预制方桩与压实填土复合地基在大型污水处理池中的设计与施工应用情况，提出了粘性填土分层压实、具有不小于80kPa承载能力的观点，如桩端土层良好，则可大幅度提高复合地基的强度。     

考虑应力作用影响的黄泛区粉土土水特征曲线分析与预测

为了研究应力作用对土水特征曲线的影响，采用应力关联土水特征仪测定不同应力下粉土的脱湿-吸湿曲线，讨论应力变化对粉土土水特征的影响规律，并利用应力与孔隙比的关系提出考虑应力作用的粉土土水特征曲线预测方法。研究发现：试样在应力逐渐增加时不易脱水，但更易吸水，非饱和粉土的持水能力随着正应力的增大而增强；脱湿曲线与吸湿曲线并不重合，有明显的回滞现象，并且吸湿曲线饱和度的变化比脱湿曲线更加剧烈；随着正应力的增大，滞回圈面积减小，滞回特性减弱。此外，将预测曲线与测得的试验曲线对比, 可知提出的考虑应力的土水特征曲线预测方法具有较好的预测精度。