水力射孔对套管强度的影响研究

水力射孔技术是一种新型的完井方式，深穿透水力射孔技术辅助定向水力压裂可以实现油气层改造和油气井增产。但是，水力射孔套管会在孔眼处造成应力集中，使得局部应力过大而削弱了套管和水泥环的强度，可能会影响套管的使用寿命。因此，文章利用有限元软件建立了射孔套管的三维有限元模型，分析了水力射孔后套管管体的应力分布，重点研究了水力射孔参数-孔密、孔径、孔深、射孔方位角等对套管强度的影响规律。分析结果表明，沿着最大水平地应力方向深穿透水力射孔，选择合适的孔密、孔径可将射孔对套管的损害降至最小。研究结果为提高水力射孔完井设计水平提供了一定的参数依据。     

黄河龙口水利枢纽坝基岩体钙质充填夹层地质分析与试验研究

龙口水利枢纽坝基岩体主要由奥陶系中统马家沟组(O2m2)灰岩组成,其中发育有多层软弱夹层。作为其中之一的钙质充填夹层,强度虽不很低,但由于处于坝基下的持力层内,间距不大,发育密集,产状平缓,是坝基浅层抗滑稳定的主要控制因素,因此,在大坝抗滑稳定分析时,应进行分析和研究。     

高性能大尺寸永磁体粘合强度的测定

介绍了一种用三点弯曲试验法测定高性能大尺寸粘接永磁体粘合强度的方法，及利用布氏硬度计的加载系统，实现100％检验粘接质量的方法。     

A Bluetooth Based Sensor Network for Civil Infrastructure Health Monitoring

Communicating with sensors has long been limited either to wired connections or to proprietary wireless communication protocols. Using a ubiquitous and inexpensive wireless communication technology to create Sensor Area Networks (SANs) will accelerate the extensive deployment of sensor technology. Bluetooth, an emerging, worldwide standard for inexpensive, local wireless communication is a viable choice for SANs because of its inherent support for some of the important requirements – low power, small form factor, low cost and sufficient communication range. In this paper we outline an approach, centered on the Bluetooth technology, to support a sensor network composed of fixed wireless sensors for health monitoring of highways, bridges and other civil infrastructures. We present a topology formation scheme that not only takes into account the traffic generated by different sensors but also the associated link strengths, buffer capacities and energy availability. The algorithm makes no particular assumptions as to the placement of nodes, and not all nodes need to be in radio proximity of each other. The output is a tree shaped scatternet rooted at the sensor hub (data logger) that is balanced in terms of traffic carried on each of the links. We also analyze the scheduling, routing and healing aspects of the resulting sensor-net topology.     

复合材料空心飞轮多环套装整体变形及应力简化精细分析

采用多环过盈装配是解决复合材料飞轮径向强度过低的有效途径之一。本文作者采用平面应力简化模型,提出了计及过盈配合后变形导致实际过盈量增大计算飞轮套装后的初终应力分布的方法;提出了基于叠加原理计算多环过盈装配旋转飞轮应力的方法;提出了保证飞轮旋转时配合界面不脱离的相关临界转速的概念和计算方法。算例分析表明:过盈配合后的变形对初终应力的影响不能忽略;过盈量和套装环数与飞轮的初终应力和相关临界转速有密切的关系。     

堆石料与基岩面直剪试验

介绍了堆石料与基岩面的现场直剪试验方法，6个组次的直剪试验结果表明，堆石料与基岩面的抗剪强度指标随基岩面坚硬度的增大而增加，并随基岩面粗糙度的加大而加大。     

Micro assembly injection moulding

Injection moulding is established as one of the most common manufacturing processes of thermoplastics due to its high degree of automation and the short cycle times. Micro injection moulding is a rapidly growing technology that allows for the efficient production of very complex micro parts in high series. The “Market Analysis for Microsystems II 2002–2005” of the Nexus Task Force anticipates a yearly growth in the field of micro system technology of about 20% (Wechsung et al. 2002). This study identifies in addition to the continuous miniaturization the growing use of polymers in micro systems (Schneider et al. 2001). No other material group offers this wide range of material properties and permits to choose processing parameters and application properties according to necessities (Gächter 2000). While the production processes of micro technical components are mainly controllable, the assembly of these components to hybrid micro systems is a bottleneck to the industrial large scale production. The assembly itself represents a large fraction of the added product value and gains in importance with growing complexity and miniaturization of the systems.     

现代电子工业Cpk评价中的特殊问题

现代电子工业生产具有许多新的特点，如果不针对具体情况，均采用传统工业生产中广泛使用的常规方法计算其工序能力指数，评价生产工艺水平，将可能导致错误的结论。总结了电子工业生产中工艺参数的典型特点，并讨论了工序能力指数的正确计算方法。     

Effects of diacrylate monomers on the bond strength of polymer concrete to wet substrates

The bond strengths of polymer concretes containing up to 15% (based on polymer resin) of diacrylate (DA) monomers were examined and compared with those without DA. A change occurring with the addition of DA monomers was an increase in the bond strength of polymer concrete to wet substrates. Zinc diacrylate (ZDA) and calcium diacrylate (CDA) were each used as an additive to monomers and resins [methyl methacrylate (MMA), polyester, and two kinds of epoxies]. The variables were amount of the DA monomers and surface conditions (wet or dry and smooth or rough). Bond strengths were measured by tension bond. ZDA was found to improve the bond strength of MMA and polyester, whereas CDA improved the bond strength of epoxies. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 991–1000, 2003     

An investigation into the effect of various chemical and physical treatments of a South African phosphogypsum to render it suitable as a set retarder for cement

The work describes various physical and chemical treatments to eliminate the deleterious effects of impurities in phosphogypsum on the delayed setting time and impaired strength development behaviour of cement to which it was added as a set regulator. The physical treatments included washing, milling, and ultrasonic treatment of the material, while the chemical treatments dealt with acidic and basic additions to the phosphogypsum during the washing stage. It was found that chemical treatment with a milk of lime solution, which is often recommended in literature, was ineffective in reducing set retardation. Treatment with ammonium hydroxide or sulphuric acid was more effective in this regard. Intergrinding phosphogypsum with slaked lime improved its effectiveness in reducing set retardation, but the use of unslaked lime was less effective and also resulted in marked reductions in compressive strengths. A combined treatment of wet milling phosphogypsum with a lime slurry in a ball mall was derived from these experiments and is recommended for full-scale plant applications.