Zum statischen System von Kellerwänden aus unbewehrtem Beton unter Erddruck

Static System of Earth Pressure loaded Basement Walls made of Non‐Reinforced Concrete Basement walls in housing are usually made of masonry or reinforced concrete. Both styles are more labor‐ and material‐intensive and therefore more expensive than basement walls without reinforcement. The required wall‐thickness of non‐reinforced walls is the most important reason for the general restraint. The design according to DIN 1045‐1 results in thicker walls compared to the design of masonry according to DIN 1053. The article illustrates the reason for the conservative design according to DIN 1045‐1 and its supposed static system in comparison to the developed design method deduced from finite‐element‐simulations. Hereby the wall thickness of non‐reinforced concrete walls can be reduced by using their ability of deformation.     

An alternative evaluation of FMEA: Fuzzy ART algorithm

Failure Mode and Effects Analysis (FMEA) is a technique used in the manufacturing industry to improve production quality and productivity. It is a method that evaluates possible failures in the system, design, process or service. It aims to continuously improve and decrease these kinds of failure modes. Adaptive Resonance Theory (ART) is one of the learning algorithms without consultants, which are developed for clustering problems in artificial neural networks. In the FMEA method, every failure mode in the system is analyzed according to severity, occurrence and detection. Then, risk priority number (RPN) is acquired by multiplication of these three factors and the necessary failures are improved with respect to the determined threshold value. In addition, there exist many shortcomings of the traditional FMEA method, which affect its efficiency and thus limit its realization. To respond to these difficulties, this study introduces the method named Fuzzy Adaptive Resonance Theory (Fuzzy ART), one of the ART networks, to evaluate RPN in FMEA. Copyright © 2008 John Wiley & Sons, Ltd.     

利用高效液相色谱-蒸发光检测器法分析鮰鱼脑中磷脂组成

对鮰鱼脑中的磷脂进行提取纯化,利用高效液相色谱-蒸发光检测器法对鮰鱼脑的磷脂含量进行检测。结果表明：鮰鱼脑磷脂中磷脂酰胆碱含量最高,占磷脂含量的45.73%,磷脂酰乙醇胺次之,含量为17.39%,磷脂酰丝氨酸含量为5.01%,磷脂酰肌醇含量为1.20%,相对较低。磷脂标准品在各自的质量浓度检测范围内线性关系良好,并且鮰鱼脑的磷脂中各组分分离效果良好,对于其他磷脂样品的测定也具有重要的参考价值。     

高钛型高炉渣熔化性温度影响因素

针对增加钒钛磁铁矿使用比例渣中TiO2质量分数提高后,对二元碱度以及MgO、TiO2和Al2O3质量分数等对高钛型高炉渣熔化性温度的影响进行了分析。结果表明,在二元碱度为0.9~1.3、MgO质量分数为7.00%~13.00%、TiO2质量分数为21.00%~25.00%、Al2O3质量分数为13.00%~16.00%、其他组? 槐涞奶跫拢孀哦疃取gO质量分数升高,熔化性温度升高;随着TiO2质量分数升高,熔化性温度先升高后降低;随着Al2O3质量分数升高,炉渣熔化性温度降低。二元碱度可以在较大范围内变化,对炉渣熔化性温度的调控作用最明显;MgO、TiO2和Al2O3的质量分数只能在较小的范围内变化,对炉渣熔化性影响不显著。在渣中TiO2质量分数为21.00%~25.00%的条件下,炉渣二元碱度不宜超过1.15,三元碱度不宜超过1.60,否则炉渣熔化性温度将显著升高。     

基于保护特性的P类电流互感器选型

为深入了解P类电流互感器饱和特性,防范互感器饱和导致保护不正确动作,通过理论推导和计算详细分析了铁芯剩磁、故障电流非周期分量、时间常数等因素对电流互感器暂态饱和特性的影响。分析结果表明关于保护用电流互感器给定暂态系数不宜低于2的选型规定不能满足线路保护和变压器保护的要求。根据分析结果,针对不同保护装置技术要求给出了保护用P类电流互感器的选型建议,并综合考虑电网实际情况,从电流互感器、保护装置、电网运行等方面提出了防范措施。     

土的动剪切模量比和阻尼比的经验模型研究

收集了大量近年来国内外公开发表的关于动剪切模量比和阻尼比的文章,提取了文中关于动剪切模量比和阻尼比随剪应变变化的试验数据,选择了统一的经验模型对粘土、淤泥质土、砂土及岩石的试验数据进行回归分析,得到了针对不同土及岩石的回归方程。将拟合结果同国内外学者给出的实测值平均曲线进行对比,验证了所选择经验模型和拟合曲线的可靠性。本文所选用的试验数据包含了新近发表文章中的试验数据,因此,本文的拟合结果可为岩土及地下工程的抗震分析提供更有意义的帮助。     

基于三次样条函数算法的逆阿贝尔变换

等离子体有关参数的径向分布,在等离子体研究中十分有意义的.只要等离子体具有轴对称和光性薄的性质,那么利用Abel逆变换便可以从所测量得到的某种物理量,沿测量方向的积分求出径向分布值.激光等离子体实验中的轴对称的X光体发射强度分布及通过多通道方法可测量电子密度和温度分布,需要采用逆阿贝尔(Abel)变换.本文采用三次样条函数近似方法计算逆Abel变换,并对两种有代表性的分布进行了计算,数值模拟结果表明:此方法反演的精度高,计算也比较简便,程序实现很容易.     

WC-Co based cemented carbides with large Cr3C2 additions

Five model alloys based on WC-16.6 vol% Co with different amounts of Cr₃C₂ (0–12 vol%) substituting WC were studied. Their microstructures were characterised with X-ray diffraction, scanning electron microscopy and transmission electron microscopy in combination with energy dispersive X-ray analysis. Thermodynamic calculations on the C-Co-Cr-W system were carried out using the Thermo-Calc software. The microstructures were related to previously published results on properties (magnetic coercivity, hardness, transverse rupture strength and indentation fracture toughness) of these materials. The aim of this work was to investigate whether the positive effect of small Cr₃C₂ additions on grain refinement and various properties remains also for large Cr₃C₂ additions. For Cr₃C₂ additions larger than 2 vol%, the most obvious effect on the microstructure was the formation of a chromium- and cobalt-rich M₇C₃ carbide. The Cr/Co ratio of this phase depends on the amount of Cr₃C₂ substituting WC. Some large WC grains were present in the WC-Co material, but not in the materials with Cr₃C₂ additions. Apart from this, no major changes of the WC grain size with Cr₃C₂ content were observed. The partial replacement of tough binder by presumably brittle M₇C₃ carbide might explain the lower toughness of these materials.     

Thin Electrolyte Layers for SOFC via Wet Powder Spraying (WPS)

The potential of the wet powder spraying (WPS) process for the depositon of thin dense films for solid oxide fuel cell electrolytes is demonstrated. In contrast to many other production methods the process allows high deposition rates. Economical aspects such as good up‐scaling, low investment costs for the equipment and short sintering times for the layers make the WPS process an interesting alternative to other deposition techniques.