拉森钢板桩基坑支护施工工艺

文章介绍了拉森钢板桩基坑支护施工工艺、沉桩措施;指出了拉森钢板桩支护是切实可行的.     

钕对AZ91镁合金组织及机械性能的影响

采用微观分析、机械性能测试及断口分析等方法研究了钕对AZ91-Nd镁合金(w(Nd)=0,0.1%,0.3%,0.5%,1.0%,1.5%)的微观组织和机械性能的影响。结果表明:Nd以固溶和金属间化合物(A l11Nd3)的形式存在时具有细化晶粒、抑制二次β相析出、使不完全离异共晶转化为离异共晶的作用;Nd通过固溶强化、析出强化和细晶强化增加了合金强度和硬度,并改善了塑性;加入Nd后合金的断裂机制从脆性解理断裂转变为准解理断裂。     

活性污泥生物吸附性能的研究

探讨了活性污泥生物吸附作用的影响因素。吸附性能随温度升高而降低,在20~30min之间,可达到吸附平衡,且温度越高,达到吸附平衡的时间越长;活性污泥对悬浮性有机物的吸附性能高于对溶解性和胶体性有机物的吸附;对高浓度污水吸附性能高于低浓度污水的吸附性能;抑制剂对污泥的吸附作用有影响。     

链轮齿数对链传动动载荷的影响

在链传动设计中链轮齿数的选择与链节距的选择有关，而分析链轮齿数对动载荷影响时所得的结论也与链节距相关．但作为一独立参数的链轮齿数对链传动动载荷的影响必有其独立的一面．就此分析了链轮齿数对链传动动载荷的影响，并就链传动设计中链轮齿数的选择进行了定性分析．     

Effect of Ca on microstructure and high temperature creep properties of AM60-1Ce alloy

A series of AM60-1Ce-xCa(x=0, 0.5, 1.5, 2.5) magnesium alloys were prepared by gravity casting method and analyzed by means of XRD, DSC and SEM. The effects of Ca on normal temperature mechanical properties and high temperature creep behavior of alloys were characterized by tensile and constant creep test.Microstructure analysis indicated that Ca was preferentially combined with Al in the alloy to form the high melting point Al_2Ca phase at the grain boundary. The addition of Ca can refine the crystal grains and reduces the content of β-Mg_(17)Al_(12) phase. With the increase of Ca content in the alloy, Al_2Ca phases at the grain boundary gradually changed to the network of lamellar structure, and replaced the β-Mg_(17)Al_(12) phase as the main strengthening phase gradually. The creep resistance of the alloy continuously increases because the high-temperature stable phase Al_2Ca firmly nailed at grain boundaries impedes the sliding of grain boundaries. However, when the addition of Ca was more than 1.5%, mechanical properties of the alloy started to decrease, which was probably due to the large amount of irregularly shaped Al_2Ca phases at the grain boundary. Experimental results show that the optimal addition amount of Ca is 1.5 wt.%.     

轧钢技术的现状和新发展

介绍了最近十几年轧钢行业的技术进步、最新发展和目前的状况,分析了热轧带钢、宽厚板、冷轧、不锈钢生产的新技术新装备以及品种开发的方向和趋势.     

对氟苯甲醛的合成

首次以对氟苯甲酸为原料,在亚磷酞胺(P[NCH,3(OCH3)]3)作用下,将之转变为4-氟-N-甲氧基-N-甲基苯甲酰胺,再经红铝(Vitride)溶液还原得到标题化合物,总收率59.4%,产物结构经IR和1HNMR表征.该法具有原料易得、操作简单、条件温和、收率好等特点.     

风味纸型香菇的研究

文章围绕香菇纸的风味和生产工艺进行了具体研究.结果表明蔗糖、食盐、生姜、胡椒粉和鸡精的添加量依次为6%,1%,0.9%,0.8%和0.5%.     

火灾场冲击波荷载作用下简支钢梁动力响应

根据火灾场不同时刻温度的变化,考虑火灾高温对结构钢弹性模量、屈服强度和钢梁塑性弯矩的影响,分析了火灾场中冲击波荷载作用下简支钢梁各个阶段不同时刻的动力响应,通过具体算例计算了火灾场工字形简支钢梁在冲击波荷载作用下弹性阶段和塑性阶段的变形,分析表明在计算火灾场冲击波荷载作用下简支钢梁的动力响应时,火灾高温对结构钢的弹性模量、屈服强度以及梁的塑性弯矩和动力响应有显著的影响。     

火灾场钢筋混凝土简支梁抗弯性能分析

通过对火灾中钢筋混凝土简支梁截面温度场和材料热力学性能分析，将混凝土分为弹性区和塑性区来分别计算其强度，建立了火灾场简支梁截面内混凝土应力和梁极限抗弯承栽力的计算公式，通过具体算例分析了钢筋混凝土简支梁截面温度场和极限承载力的变化规律和原因。