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991.
地下空间虽然已成为城市规划的一部分,但由于受制于各种因素,两者尚未能紧密结合。通过本文所举的案例,提出了可实施的方法并展示了其效果,可以支持地下空间与城市规划同步实施的设想。  相似文献   
992.
993.
When a woven fabric is subject to a normal uniform loading, its properties such as tightness and through-thickness permeability are both altered, which relates to the fabric out-of-plane deformation (OPD) and dynamic permeability (DP). In this article, fabric OPD is analytically modelled through an energy minimisation method, and corresponding fabric DP is established as the function of loading and fabric-deformed structure. The total model shows the permeability a decrease for tight fabric and an increase for loose fabric when the uniform loading increases. This is verified experimentally by fabric OPD, static and dynamic permeabilities. Experimental tests for both permeabilities showed good agreement with the corresponding predictions, indicating the fact that tight fabric becomes denser and loose fabric gets more porous during OPD. A sensitivity study showed that an increase of fabric Young’s modulus or a decrease of fabric test radius both lead to an increase of DP for tight fabric and opposite for loose fabric. The critical fabric porosity and thickness were found for inflexion of fabric DP trend during the OPD, which contributes to the optimum design of interlacing structure applied to protective textiles and composites.  相似文献   
994.
李龙 《阀门》2012,(3):4-6
介绍了圆孔方形法兰的强度分析和计算方法。  相似文献   
995.
996.
通过塑料烟密度仪和热重分析仪(TGA)研究了7种典型装饰材料的热分解特性和静态生烟性。结果表明:辐射功率越大,样品的比光密度和质量光密度越大;在相同的辐射功率下,有焰时的比光密度和质量光密度要明显小于无焰时的;材质相同时比光密度和质量光密度随着样品厚度的增加而减少。对比TGA实验结果可知,烟密度实验中的质量损失率正比于TGA的热失重率,即材料的热重失重率大,烟密度实验中的质量损失率也大。  相似文献   
997.
The mechanical properties of heat affected zone (HAZ) of two commercial high-Nb X80 grade pipeline steels with different alloy elements were investigated using thermal simulation performed on a Gleeble-3500 thermal simulator. The results showed that the high-Nb steels have excellent weldability. Embrittlement regions appear in coarse grain heat affected zone (CGHAZ) and intercritically heat affected zone (ICHAZ); Softening region appears in fine-grain heat affected zone (FGHAZ), and the strength here was even lower than 555 MPa as required in the standard. Meanwhile, with the increase of heat input, the strength and the toughness of HAZ of steel with high Nb, C and lower alloy decrease notably. Therefore, take into account the welding procedure during manufacture of weld pipe, suitable amount of alloy elements, such as Cr, Ni, Cu, Mo and so on, is necessary for high Nb X80 heavy-thick steel plate.  相似文献   
998.
999.
Abstract

Among the parameters that affect photolithography, the most important are exposure and development time which affect the coating photoresist characteristics. This study further researches the relationship between the exposure and development time using a high speed image inspection system, and the relationship between the development time and photoresist depth using a Scanning Probe Microscope (SPM). A partial scan CCD camera and high speed frame capture card were used to obtain the photoresist development processing parameters. The experimental results verified that this imaging system provides an economical and effective method for producing a micro‐photo‐etched product. It is expected that these experiments can also offer some good references useful in the micro electro mechanical industrial field.  相似文献   
1000.
Open Learner Models (OLMs) have great potential to support students’ Self-Regulated Learning (SRL) in Intelligent Tutoring Systems (ITSs). Yet few classroom experiments have been conducted to empirically evaluate whether and how an OLM can enhance students’ domain level learning outcomes through the scaffolding of SRL processes in an ITS. In two classroom experiments with a total of 302 7th- and 8th-grade students, we investigated the effect of (a) an OLM that supports students’ self-assessment of their equation-solving skills and (b) shared control over problem selection, on students’ equation-solving abilities, enjoyment of learning with the tutor, self-assessment accuracy, and problem selection decisions. In the first, smaller experiment, the hypothesized main effect of the OLM on students’ learning outcomes was confirmed; we found no main effect of shared control of problem selection, nor an interaction. In the second, larger experiment, the hypothesized main effects were not confirmed, but we found an interaction such that the students who had access to the OLM learned significantly better equation-solving skills than their counterparts when shared control over problem selection was offered in the system. Thus, the two experiments support the notion that an OLM can enhance students’ domain-level learning outcomes through scaffolding of SRL processes, and are among the first in-vivo classroom experiments to do so. They suggest that an OLM is especially effective if it is designed to support multiple SRL processes.  相似文献   
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