超大型轴流转桨式水轮发电机组定子组装工艺

安谷水电站机组是超大型轴流转桨式水轮发电机组,定子机座散装运输到场,机座安装采用现场焊接方式。为克服机座尺寸大、质量重、当地温差大等定子安装精度的不利影响,介绍了定子机座焊接组装、定位筋安装调整、铁芯叠片和铁损试验等关键工序,并通过分析机组定子安装工艺和实践总结,优化了施工工序。实践证明定子组装质量得到严格控制,各项控制指标均满足规范标准,其安装工艺对同类型机组定子安装具有指导意义。     

粘土材料单轴压缩及强度特性试验研究

为探讨压实粘土材料在单轴加载条件下的强度及变形特性,考虑含水率、干密度、各向异性、碎石掺量等因素,对立方体压实粘土材料进行了单轴压缩试验,并分析了弹性模量、抗压强度的参数相关性。试验结果表明,随着含水率的减小或干密度的增加,压缩粘土材料弹性模量、抗压强度逐渐增加,其中,含水率是控制压实粘土材料脆韧性破坏特征的主要因素;当单轴加载方向与击实方向平行时,其抗压强度、弹性模量分别为加载方向与击实方向垂直时的1.7、1.1倍,说明压实粘土存在一定的各向异性;掺入碎石后使得压实粘土材料内部存在大量的软弱界面,随着碎石增多,其抗压强度逐渐减小;掺碎石前、后的粘土试样的弹性模量和抗压强度呈现一定的正相关性,可采用幂函数、线性函数进行拟合,但碎石的掺入降低了其相关性系数。     

三峡库区黄花城河段泥沙淤积情况的二维数值模拟

为准确反映三峡库区真实的泥沙淤积情况,以已有二维平面水沙模型为基础,考虑絮凝及床面泥沙固结后密度变化等因素,改进细沙冲淤判别标准,推导出泥沙运动及河床演变方程,将改进后的模型应用于三峡水库典型淤沙河段黄花城河段的泥沙冲淤变化模拟中,模型计算值与实测值对比结果表明,模型模拟精度较好,改进的泥沙模型可较真实地反映库区细沙的输移特性。在此基础上,利用该改进模型预测水库运行未来20年(2013~2032年)黄花城河段的演变趋势,发现主要淤积部位在左汊,且重点淤积部位逐渐向左汊出口转移,右汊淤积发展相对缓慢,该河段仍保持淤积状态,但整体淤积速率有所放缓。研究成果对于准确预判三峡库区的泥沙淤积状况意义重大。     

复杂层状坝基重力坝抗震安全评价

为研究复杂层状坝基的混凝土重力坝非溢流坝段的抗震性能,采用ADINA程序建立非线性有限元分析模型,以接触单元模拟缓倾角的软弱结构面,以concrete本构模型模拟混凝土材料在地震中的开裂、压碎动态特性,以Mohr-Coulomb本构模型模拟地基岩体材料在地震中的塑性屈服特性,分析了坝体位移、应力、接触面状态及极限抗震能力,研究了非溢流坝段在不同概率等级地震作用下的地震响应与破坏模式,并对复杂层状坝基重力坝的安全性能进行整体评价。结果表明,复杂层状地基结构的重力坝在地震中层间接触面能够产生一定滑移,但对坝体的应力和极限抗震能力影响不大。     

基于Web服务的中小型企业协同商务系统的研究

协同是企业发展的重要核心之一。特别在中小型企业中开展协同商务有利于企业竞争优势的提高在对Web服务技术进行分析的基础上．讨论了基于Web服务技术对中小型企业协同商务系统的构建。     

胶粘剂在刀具制造中的应用

在自动化生产中,金属切削刀具在使用条件下的质量大多数情况下取决于刀片的夹固方法。若采用粘接技术,则既可以避免传统夹固方法的一些缺点,又可以省去一些工序,如铣、磨、钳工加工等等工序。然而用胶粘剂来装配刀具的方法仍未能得到广泛的应用,这是因为已知牌号的胶粘剂不具备足够的物理饥饿性能。当研制出用含碳和有机硅的化合物改往的一系列高强度胶粘剂之后,大大地扩大了刀具胶接接头的使用温度范围。表中示有在较高温度下一些切削工具用胶粘剂的物理一机械性能试验结果。     

Thermoelectric properties of Bi_（1.5）Pb_（0.5）Sr_（2-x）La_xCo_2O_y polycrystalline materials

Polycrystalline samples of Bi 1.5 Pb 0.5 Sr 2-x La x Co 2 O y (x = 0.1, 0.2, 0.3) with a layered structure were prepared by solid-state reaction method. All samples are p-type semiconductors. The thermoelectric properties, namely, the electric resistivity (ρ), Seebeck coefficient (S), and power factor (S 2 /ρ) of the samples are dependent on chemical composition. The values of ρ, S, and S 2 /ρ increase with an increase in temperature for all samples. The substitution of Pb 2+ for Bi 3+ and La 3+ for Sr 2+ improves the thermoelectric properties of the Bi 2 Sr 2 Co 2 O y system owing to the simultaneous decrease of electric resistivity and increase of Seebeck coefficient. As a result, the optimal thermoelectric property has been obtained in Bi 1.5 Pb 0.5 Sr 1.7 La 0.3 Co 2 O y and the power factor can reach 2.1 × 10-4 W·m-1 K-2 at 998 K.     

The effect of lactose, NaCl and an aero/anaerobic environment on the tyrosine decarboxylase activity of Lactococcus lactis subsp. cremoris and Lactococcus lactis subsp. lactis

The aim of this work was to study, under model conditions, combined effects of the concentration of lactose (0-1% w/v), NaCl (0-2% w/v) and aero/anaerobiosis on the growth and tyramine production in 3 strains of Lactococcus lactis subsp. lactis and 2 strains of L. lactis subsp. cremoris. The levels of the factors tested were chosen with respect to the conditions which can occur during the real process of natural cheese production, including the culture temperature (10 ± 1 °C). In all strains tested, tyrosine decarboxylation was most influenced by NaCl concentration; the highest production of tyramine was obtained within the culture with the highest (2% w/v) salt concentration applied. Two of the strains L. lactis subsp. lactis produced tyramine only in broth with the highest NaCl concentration tested. In the remaining 3 strains of L. lactis, tyramine was detected under all conditions applied. The tested concentration of lactose and aero/anaerobiosis had a less significant effect on tyramine decarboxylation. However, it was also found that at the same concentrations of NaCl and lactose, a higher amount of tyramine was detected under anaerobic conditions. In all strains tested, tyramine decarboxylation started during the active growth phase of the cells.     

高能脉冲精密冷补技术用于修复零件表面局部缺损

高能脉冲精密冷补技术由于其独特的能量输出方式,在实现金属零件表面修复时具有修复速度快、热量输入小和结合强度高的特点。通过对液压柱塞杆划伤表面的实际修复和修复区域的性能测试,结果表明:修复层与基体无明显气孔,结合紧密,HAZ宽度为130μm,修复层平均显微硬度为520 HV,耐磨性能较基体提高36.4%。说明高能脉冲精密冷补技术是一种操作简单,性能可靠的新型修复技术。     

MARTENSITIC AND R PHASE TRANSFOR MATIONS IN NiTiand NiTiHf

１　ＩＮＴＯＤＵＣＴＩＯＮＳｈａｐｅｍｅｍｏｒｙａｌｌｏｙｓ（ＳＭＡｓ）ａｒｅｅｘｃｅｌｌｅｎｔｃａｎｄｉｄａｔｅｓｆｏｒｃｏｎｔｒｏｌｓｙｓｔｅｍｓａｎｄａｒｅｃｏｍｍｏｎｌｙｒｅｆｅｒｒｅｄｔｏａｓ“ｓｍａｒｔ”ｍａｔｅｒｉａｌｓｄｕｅｔｏｔｈｅｉｒａｂｉｌｉｔｙｔｏｃｈａｎｇｅｓｈａｐｅｗｉｔｈｔｅｍｐｅｒａｔｕｒｅ．Ｔｈｅｓｅａｌｌｏｙｓｃａｎａｌｓｏｇｅｎｅｒａｔｅｓｉｇｎｉｆｉｃａｎｔａｍｏｕｎｔｓｏｆｓｔｒａｉｎ（ａｎｄｓｔｒｅｓｓ）ａｎｄａｒｅｉｄｅａｌｆｏｒｕｓｅｉｎａｃｔ…