ZL型悬移顶梁液压支架在薄煤层超前支护中的推广与应用

翟镇煤矿为解决超前支护难题,不断探索新型支护形式。ZL型悬移顶梁液压超前支架应用为顺槽超前支护提供了一种全新的、机械化程度较高的支护方式。该型超前支护支架的应用切实解决了现场存在的高度、支护强度问题,取得了较好的效果,具有较高的推广价值。     

某小区地下车库入口坡道抗浮事故处理方法

针对某小区地下车库入口处汽车坡道抗浮事故,通过对一些常用抗浮措施进行比较和分析,最后选用增加底板翼缘,用毛石混凝土反压,在坡道侧墙上增加混凝土构架等系列措施来保证车库入口坡道的抗浮稳定性。经实施,取得了良好效果,值得进一步推广。     

Improved hydrogen storage reversibility of LiBH4 destabilized by Y(BH4)3 and YH3

In the present study, the synthesis of two different LiBH₄–Y(BH₄)₃ and LiBH₄–YH₃ composites was performed by mechanochemical processing of the 4LiBH₄–YCl₃ mixture and as-milled 4LiBH₄–YCl₃ plus 3LiH. It was found that Y(BH₄)₃ and YH₃ formed in situ during milling are effective to promote LiBH₄ destabilization but differ substantially from each other in terms of the dehydrogenation pathway. During LiBH₄–Y(BH₄)₃ dehydriding, Y(BH₄)₃ decomposes first generating in situ freshly YH₃ and subsequently, it destabilizes LiBH₄ with the formation of minor amounts of YB₄. About 20% of the theoretical hydrogen storage was obtained via the rehydriding of YB₄–4LiH–3LiCl at 400 °C and 6.5 MPa. As a novel result, a compound containing (B₁₂H₁₂)²⁻ group was identified during dehydriding of Y(BH₄)₃. In the case of 4LiBH₄–YH₃ dehydrogenation, the increase of the hydrogen back pressure favors the formation of crystalline YB_4, whereas a reduction to ≤0.1 MPa induces the formation of minor amounts of Li₂B₁₂H₁₂. Although for hydrogen pressures ≤0.1 MPa direct LiBH₄ decomposition can occur, the main dehydriding pathway of 4LiBH₄–YH₃ composite yields YB₄ and LiH. The nanostructured composite obtained by mechanochemical processing gives good hydrogen storage reversibility (about 80%) regardless of the hydrogen back pressure.     

基于偏最小二乘法的综合弹性模量反演分析

为获取符合实际的坝体综合弹性模量,利用引张线实测资料,将偏最小二乘法运用于统计模型中分离出水压分量,采用Hypermesh软件构建了有限元模型,并应用Marc程序计算水压作用下的位移量,基于常规反演法推求坝体及坝基的综合弹性模量。实例表明,偏最小二乘法分离效果更好,反演结果精度更高,能满足对大坝安全监控的要求。     

人工神经网络及其在盐田水体遥感图像分类中的研究

卫星遥感技术的发展为盐业生产资源监测提供了有效的手段.文章首先介绍了遥感图像分类的原理及其常用方法,接着就人工神经网络基本概念和常用算法进行阐述,并着重介绍了反向传播网络(BP网络),最后以天津塘沽盐场区域为研究对象,用BP网络进行了盐田水体识别实验.     

岩土工程数值分析中反分析方法探讨

通过查阅大量关于岩土工程方面的反分析文献资料,简要叙述了岩土工程反分析的概念,主要方法,并且介绍了目前具有代表性的反分析模型及各自的特点和适用性,同时阐述了在岩土工程非确定性反分析研究的发展方向,以期解决复杂岩土问题。     

桥涵台背回填材料的评价与施工质量控制

为提高桥涵台背回填质量,本文在分析桥涵台背病害成因基础上,评价目前主要回填材料的优劣,总结台背回填施工要点及其质量控制方法。分析表明,桥涵台背回填可因地制宜选择回填料,但不同的填料应采用相适应的施工方法和质量控制手段。     

赤峰桥斜拉索张拉施工技术

通过介绍赤峰桥环氧涂层钢绞线群锚拉索张拉施工工艺,解析施工特点和工艺流程,运用＂等值张拉法＂的施工技术以单根等值张拉的方式解决整根索体一次张拉的困难,从而使得成桥线型与设计线型相吻合,保证了成桥质量和安全。     

利用粒子群算法优化反向传播人工神经网络模型预测熏肠中4种多环芳烃含量

构建基于粒子群优化(particle swarm optimization,PSO)算法的反向传播人工神经网络(back propagation artificial neural network,BP-ANN)预测模型,对熏肠中4种多环芳烃(polycyclic aromatic hydrocarbons,PAHs)...     

Variation in optic zone radii of a contact lens during manufacturing and the effects of temperature on this variation

There is little information in the literature on the causes of variation in the optic zone radii of a contact lens and the effects of temperature on this variation. In this study, the lathe cutting method of producing contact lenses was reviewed. The cause of the variation in the back optic zone radius was then identified as change in the operating condition from that of the calibrating one. Also, using finite element and theoretical methods, it was found that the effect of an increase in lens blank temperature is to make the back optic zone radius obtained steeper than that required, and this effect was verified experimentally.