基于谐波分析氧化锌避雷器阻性泄漏电流带电测量的一种新方法

本文讨论了通过测量泄漏电流确定氧化锌避雷器绝缘状况的几种方法。提出了一种基于泄漏电流谐波分析的新方法,它的主要优点是对系统电压谐波的低灵敏度,减小系统电压谐波对测量结果的影响,因而获得很好的效果。     

耐腐蚀的动态可靠性和寿命RD理论和方法

根据腐蚀的特点 ,确定腐蚀深度值的概率分布形式呈Ⅰ型极大值分布、腐蚀寿命呈I型极小值分布。并据此建立了耐腐蚀的可靠度计算方法和零件的耐腐蚀可靠寿命的计算方法     

纳米TiO_2、SiO_(2-X)的紫外屏蔽性能分析及其在聚酯中的应用

介绍了纳米材料TiO2 和SiO2 X 粉体。应用透射电子显微镜、X射线衍射仪、紫外分光光度计等对纳米TiO2 和SiO2 X 的表面形貌、微观结构进行了表征。通过实验证明了纳米TiO2 具有优良的吸收紫外线的性能 ;而纳米SiO2 X具有较好的反射紫外线的性能。纳米材料有催化作用 ,缩聚时加入纳米材料 ,能减少缩聚时间     

紫羊绒脱色处理工艺初探

叙述紫羊绒脱色漂白的新工艺，即羊绒先经过媒处理后，再经氧化还原漂白，并对工艺进行了初步探讨。     

耐候性AAS树脂的制备及对PVC的改性

采用乳液聚合接枝法,以丙烯酸丁酯橡胶为核,以苯乙烯丙烯腈共聚物为壳,制备了AAS树脂。并用AAS树脂对硬质聚氯乙烯(PVC)进行了改性。同时考察了复合稳定剂对PVC加工性能的影响。实验结果发现:当AAS树脂质量分数由10%提高到30%时,材料的冲击强度由200 J/m提高到了1 000 J/m,复合稳定剂的加入明显提高了PVC树脂的挤出性能。     

345 MPa级耐候钢切割分层及冷弯开裂原因分析

345 MPa级耐候钢在冷加工过程中出现切割分层以及冷弯开裂两种缺陷。利用金相显微镜、扫描电镜、能谱仪对以上缺陷进行了观察、检测与分析。结果表明,切割分层缺陷与钢材基体中的Mn S夹杂有关。带状Mn S夹杂硬度高,脆性大,在切割变形过程中与基体组织变形不协调导致分层。冷弯开裂缺陷与钢材基体中的P偏析有关。P含量较高的偏析带组织异常粗大,塑性低。在冷弯变形过程中,偏析带内的夹杂物周围、偏析带与基体结合处易滋生裂纹。随着变形量的加大以及裂纹扩展,偏析带和钢板外侧基体断裂,形成冷弯开裂缺陷。     

抗冲型ACR树脂的改性效果及应用

介绍齐鲁石化公司研究院生产的抗冲性ACR树脂QWM－981,考察了ACR树脂的改性效果,结果表明,QWM－981的改性效果与国外同类型产品相似,但玻璃化温度低约－48.79℃,流变加工性能与国外同类型产品相似,可改进硬PVC的加工性和表面光洁。     

Properties of retrograded and acetylated starch preparations Part 2. Dynamics of saccharification with amyloglucosidase and rheological properties of resulting pastes and gels

Various procedures have been used to produce preparations of retrograded starch, by subjecting it to acetylation with methods used in the food industry. The resultant starch preparations were evaluated for their degree of acetylation through titration, swelling power and solubility in water at 80 °C, and saccharification dynamics as affected by amyloglucosidase. Rheological properties of pastes and gels of native starch and modified starch preparations were characterized with the use of a sweep temperature test as a dependency of the storage modulus (G′) and loss modulus (G″) on temperature. In addition, flow curves of pastes were plotted and mechanical spectra of gels of the preparations examined were determined. These modifications had a significant effect on the preparations produced. Retrograded and acetylated starch preparations were characterized by greater solubility in water and greater swelling power, and were less susceptible to amyloglucosidase than the non-acetylated preparations. Rheological properties of the pastes and gels were affected by the methods of their production. Acetylation was found to significantly affect a decrease in the storage modulus value during heating. Pastes of the native starch and modified starch preparations were characterized by the non-Newtonian flow, shear thinning with a tendency to yield stress. In turn, the mechanical spectra demonstrated that - in the concentration applied - both native starch and modified starch preparation were forming weak gels.     

抗性消声器内部流场对传递损失的影响研究

柴油客车需求量剧增导致市区噪声等级提升,高性能配套消声器是抑制此类声源的有效措施之一.运用流体力学原理和声学有限元法,进行数值仿真试验能降低设计成本,缩短研发周期.首先在UG环境建立目标消声器三维模型,导入ANAYSICEM CFD网格划分平台作网格划分;其次将验证的消声器网格模型导入ANSYS Fluent环境,量化...     

耐蚀泵用高硅铸造不锈钢的组织与耐蚀性能的研究

设计了新型高硅铸造不锈钢，研究了该钢的组织和耐蚀性能。结果表明，在高温浓硫酸介质中，新型高硅不锈钢比Lewment55合金具有更好的耐蚀性，且其成本低，综合性能好，具有广阔的应用前景。