浅谈钢筋混凝土结构含钢量的控制措施

根据实际工程经验,简单阐述了控制钢筋混凝土结构含钢量的一些措施,重点强调了设计中应注意：地下室底板的最小配筋率;剪力墙的配筋率应根据结构高度和规则性合理调整;框架柱外围箍筋和内部箍筋可采用不同级别钢筋及楼板厚度和钢筋等级的合理选择等问题。     

重组竹热压板坯内部温度变化的研究

利用热电偶测试重组竹压制过程中板坯内部的温度变化,探讨了板坯厚度、板坯含水率、热压温度等因素对重组竹传热的影响。结果表明:①利用检测结果绘制的散点图趋势线有很好的线性关系。②重组竹热压过程中中心层温度的变化曲线可分温度缓慢传递阶段、快速升温阶段和慢速升温阶段。③板坯内含水率越高其传热效果越好。④酚醛树脂在高温下固化形成的隔热层对温度传导不利。     

裂缝密集型面板渗流的等效准连续介质模型

基于等宽缝隙稳定流的运动规律,首先建立了单一面板裂缝的渗流模型,在此基础上建立了裂缝密集型面板渗流的等效准连续介质模型。结果表明,对裂缝密集型面板按等效准连续介质模型进行模拟,可以获得较为准确的坝体渗流计算结果,且该模型具有有限元网格剖分简单、计算效率高等优点,是一种较为准确实用的面板渗流计算模型。     

基于NNDO滑模反步法的中密度纤维板板厚控制研究

针对中密度纤维板板厚纠偏位置伺服系统存在参数的不确定性以及系统外部的干扰等因素引起的板厚偏差问题,提出了一种基于NNDO的滑模反步控制方法。结果表明：加入NNDO的滑模反步控制可以实现对位置信号的快速跟踪,跟踪误差的收敛速度也更快,减弱了滑模反步控制器的控制输入抖振问题,改善了闭环系统的动态性能和对于干扰的鲁棒性,提高了控制器的控制性能。     

A Research on Submerged Entry Nozzles for Thin Slab Continuous Casting

In view of the process characteristics of thin slab casting with a vertical-arcmould and super thin submerged nozzles, the fluid flow laws in a mould and in scarch of reasonablesu bmerged nozzle patterns have been physieally simulated. The fluid flow states of several typiealnozzleS in moulds were studied through water model experimen ts. The shape and dimensions of asuitable submerged nozzle have heen optimized for industry trials.     

Chinese experience on plastic membrane-concrete thin slab lining for canals

Of the many types of canal linings in the world, concrete, compacted earth and buried plastic membrane linings are most commonly used. Another type of canal lining — plastic membrane-concrete thin slab lining — has been used in China since 1975. It has the advantages of both plastic and concrete linings, including good seepage control, smooth lining surface, steeper side slopes, effective film valve to eliminate external water pressure, reliability, durability, and lower construction cost. This type of canal lining is a viable alternative to other types of linings, especially in developing countries where the cost of labor is low or farmland is limited.     

角点支承钢筋混凝土双向密肋楼盖破坏形态研究

在角点支承钢筋混凝土双向密肋楼盖试验的基础上,提出有关这种楼盖板—次肋和板—次肋—主肋的8种可能破坏形态,并分别推导了它们的极限荷载公式 当楼盖的几何尺寸和配筋等条件已知时,可以算得每种破坏形态的极限荷载值,其中,与最小极限荷载对应的破坏形态就是真实的破坏形态 通过一块5.46m×10.92m的两跨角点支承钢筋混凝土双向密肋楼盖短期荷载试验,将计算结果与试验结果进行了比较     

Osteopetrosis in a neonatal donkey

Osteopetrosis is a rare disorder characterised by a defect in osteoclastic bone resorption. This report describes osteopetrosis in a neonatal donkey that suffered a displaced tibial fracture. Radiographic examination identified generalised reduction in medullary cavity size, thickened mid‐diaphyseal cortices and conical metaphyseal bone extending toward the mid‐diaphysis of long bones. Postmortem examination identified additional fractures and brittle bones. Histologically, osteoclasts were absent in multiple bone sections. Diaphyseal cortices consisted of concentric bone lamellae with marrow tissue infiltration. Large wedges of secondary spongiosa extended from the metaphyseal growth plate. Clinical and histopathological features were similar to an osteoclast‐deficient, autosomal recessive form of osteopetrosis in humans.     

水泥混凝土路面断板原因剖析与防治

水泥混凝土路面产生断板后，对路面的使用品质及行车的安全性和舒适性都会有较大的影响。断板数量的多少是评定路面状况的主要依据。文中较为详细地介绍了水泥混凝土路面断板危害性、产生的原因、防治及处理措施。