3,9-二羟甲基-3′,9′-二苯基-1,5,7,11-四氧杂螺环[5,5]十一烷的合成及聚合反应

利用苯乙醛与甲醛之间的坎尼扎罗反应合成２－苯基－２－羟甲基丙二醇，进而合成新的螺环化合物：３，９－二羟甲基－３′，９′－二苯基－１，５，７，１１－四氧杂螺环［５，５］十一烷．通过红外光谱、核磁共振氢谱和元素分析证实了它的组成和结构．在三氟化硼单乙胺络合物的作用下，该化合物能够进行双开环聚合反应．用膨胀计法跟踪测试了在聚合反应过程中它的体积膨胀率约为３．８％，并对聚合反应机理作了初步探讨．     

FEM for evaluation of weight functions for SIF, COD and higher-order coefficients with application to a typical wedge splitting specimen

In the evaluation of accurate weight functions for the coefficients of first few terms of the linear elastic crack tip fields and the crack opening displacement (COD) using the finite element method (FEM), singularities at the crack tip and the loading point need to be properly considered. The crack tip singularity can be well captured by a hybrid crack element (HCE), which directly predicts accurate coefficients of first few terms of the linear elastic crack tip fields. A penalty function technique is introduced to handle the point load. With the use of these methods numerical results of a typical wedge splitting (WS) specimen subjected to wedge forces at arbitrary locations on the crack faces are obtained. With the help of appropriate interpolation techniques, these results can be used as weight functions. The range of validity of the so-called Paris equation, which is widely used in the evaluation of the COD from the stress intensity factors (SIFs), is established.     

清梳联技术问题和发展现状的分析与讨论

针对清梳联工艺流程，讨论了与工艺质量相关的若干问题，分析了目前技术发展水平，指出我国清梳联的发展方向是进一步提高生产效率、提高产品质量和完善系统功能．     

Risk Assessment Methodology for Underground Construction Projects

This paper presents a risk assessment methodology for underground construction projects. A formalized procedure and associated tools were developed to assess and manage the risks involved in underground construction. The suggested risk assessment procedure is composed of four steps of identifying, analyzing, evaluating, and managing the risks inherent in construction projects. The main tool of the proposed risk assessment methodology is the risk analysis software. The risk analysis software is built upon an uncertainty model based on fuzzy concept. The fuzzy-based uncertainty model is designed to consider the uncertainty range that represents the degree of uncertainties involved in both (1) probabilistic parameter estimates and (2) subjective judgments. Other tools developed in this study include the survey sheets for collecting risk-related information and the detail check sheets for risk identification and analysis. The paper finally discusses a detailed case study of the developed risk assessment methodology performed for a subway construction project in Korea.     

大尺寸容器开口接管雌雄样板的打印

针对大尺寸容器开口接管的雌雄样板打印问题,提出了先分条打印再组对的方法,以圆筒开口接管为例,利用VBA对AutoCAD进行二次开发,编制了相应雌雄样板放样软件,解决了在可绘制图幅有限的绘图机上打印大尺寸样板的问题.     

Underground space needs an interdisciplinary approach

During a very long period of time, civil engineers have been the only ones to be designated as the experts for underground space, while the planners and architects were the ones of the development at the surface. This silo approach to work is now a thing for the past in most major cities, but solving this fragmentation of the disciplines does not happen overnight. It first took a few thinkers to promote and publish on the subject, such as Edouard Utudjian, founder of GECUS in 1937, and also that planners abandon their ambiguous position on this invisible space, become part of multi-disciplinary teams and participate in the dissemination of new knowledge, particularly through some international associations such as ACUUS. With biennial scientific conferences dating back to 1983, the organization actively promotes since partnerships amongst all actors in the field of planning, management, research and uses of urban underground space in all its forms. The originality of ACUUS comes from its success in attracting public, private and university levels into a cohesive network of mutual cooperation, which is not so common in international organizations.     

Morphological enhancement of microscopy mineral image using opening‐ and closing‐based toggle operator

To enhance unclear microscopy mineral images, an algorithm based on toggle operator using opening and closing is proposed in this paper. Firstly, the specified toggle operator using opening and closing through designing the selection rules is analysed. Secondly, after importing the multiscale theory into the specified toggle operator, useful mineral image features, especially the mineral details, are extracted using the multiscale theory‐based toggle operator. Finally, the mineral image is enhanced through the strategy of enlarging the contrast between the extracted bright and dark image features. Experimental results on different types of mineral images verified that the proposed algorithm could effectively enhance mineral images and performed better than some other algorithms. The enhanced mineral image is clear and contains rich mineral details, whereas the grey scale distribution of the original mineral image is appropriately maintained. This would be useful for the further mineral analysis. Therefore, the proposed algorithm could be widely used for image‐based mineral applications.     

Geotextile filtration opening size under tension and confinement

Nonwoven geotextiles have been used as filters in geotechnical and geoenvironmental works for half a century. They are easy to install and can be specified to meet the requirements for proper filter performance. There are situations where a geotextile filter may be subjected to tensile loads, which may alter relevant filter properties, such as its filtration opening size. Examples of such situations are silty fence applications, geotextile separators, geotextile tubes and geotextiles under embankments on soft soils. This paper investigates the effects of tensile strains on geotextile pore dimensions. A special equipment and testing technique allowed tests to be carried out on geotextile specimens subjected to tension and confinement. The results obtained showed that the variation in filtration opening size depends on the type of strain state the geotextile is subjected, under which the geotextile pore diameter may remain rather constant or increase significantly. However, confinement reduces the geotextile filtration opening size independent on the strain mobilised. An upper bound for the filtration opening size of strained nonwoven geotextiles is introduced and was satisfactory for the geotextile products tested.     

Why underground space should be included in urban planning policy – And how this will enhance an urban underground future

Cities worldwide tend to overlook an invaluable asset that lies beneath their surfaces. Most cities and urban regions are unaware of the benefits underground space use has to offer, both for climate inflicted and spatial constraints: In many cities, infrastructure development is being outpaced by population growth. Climate change effects are requiring radical new approaches in terms of coping with for example excessive rainfall. The available space at the surface is rapidly being used up and the biggest danger is that built-up spaces are taking over the public green spaces of cities thereby threatening livability and quality of life. Urban underground space forms a societal asset, which is often unappreciated and underestimated in terms of the role it can play within dynamic city environments and associated challenges.This paper will explore the ways in which urban underground space can be optimally integrated into the dynamic urban context. It also explores the often contradictory functions that make underground space use complicated from a planner’s perspective. The first-come-first-served strategy of underground space use has left many cities wondering how they are going to cope with the self-inflicted “chaos” under the surface. The often mono-functional uses of the underground lead to sub-optimal space use. Most cities and urban regions are unaware of the benefits underground space use has to offer. In guiding the future use of urban underground space, a comprehensive policy framework guiding its development is lacking on which decisions can be based. This often leads to the non-sustainable use of this important asset. It will be argued that both vision and planning are needed to be able to make the best use of this underrated underground real estate.The authors will also debate that just understanding the potential of underground space is not enough. Realising its actual potential and facilitating its development will require a spatial dialogue between many stakeholders, including planners, engineers, developers and public decision makers.     

Dynamic response of a double-deck circular tunnel embedded in a full-space

A three-dimensional dynamic model for calculating the ground-borne vibrations generated by harmonic loads applied on the interior floor of a double-deck circular tunnel is developed. The response of the system is obtained coupling the interior floor subsystem and the tunnel-soil subsystem in the wavenumber-frequency domain. The interior floor is modeled as a thin plate of infinite length in the train circulation direction and the tunnel-soil system is described using the Pipe in Pipe model. Some numerical instabilities of the resulting expressions are overcome by using analytic approximations. The results show that the dynamic behavior of the interior floor clearly influences the magnitude of the coupling loads acting on the tunnel structure. The soil response to a harmonic load acting on the double-deck tunnel is compared to the one obtained for the case of a simple tunnel finding significant differences between them for the whole range of frequencies studied. The proposed model extends the prediction of train-induced vibrations using computationally efficient models to this type of tunnel structure.