汽轮发电机振动故障专家系统诊断方法研究

通过对汽轮发电机振动故障机理、故障特征和故障原因的分析,建立了汽轮发电机振动故障特征表,根据振动故障特征表的知识以决策树的形式构建了汽轮发电机振动故障专家系统知识库,并建立了汽轮发电机振动故障专家系统决策树诊断模型。最后通过发电机振动故障实际案例对汽轮发电机振动故障专家系统诊断方法进行了验证,证明了其准确性和可行性。     

低速重载轴承的故障诊断

分析了低速重载轴承的故障特点及其诊断方法,分别就内圈故障、外圈故障、滚动体故障、保持架故障的诊断方法以及故障的严重程度的判断进行了讨论,并用此方法对两例轴承故障实例进行了分析。     

棒线裙板中继故障的解决方法

裙板中继故障是棒材生产线的一种主要故障,发生频繁、故障较难预测,同时处理时间较长,对生产影响较大。文章介绍了描述了八钢2#棒材裙板中继故障的解决办法,较好解决了此故障。     

逆变器故障处理实践

介绍了石钢小型棒材连轧生产线西门子传动柜3次过流报警故障经过,故障均为F011报警信号,记录波形和现场状况有很大差异。按照事故处理原则,通过分析和试验找出了原因,分别为:触发板故障、控制电源板连线故障和负荷故障。为今后快速查找故障,积累了实践经验。     

数控机床故障维修实例与分析

数控机床故障一般有数控系统本身的硬件故障,主轴放大器和主轴伺服电机故障,进给伺服放大器和进给电机故障,机床PMC(I/O)故障,操作错误及编程错误故障,外界干扰引起的故障,现场机床电气部分故障,机床机械本体故障等。通过介绍数控加工中心实际生产使用中的几个相关故障现象,进行故障原因分析,给出了诊断过程以及解决问题的办法。     

GK1F型机车柴油机机油压力低故障的分析与处理

分析了GK1F型机车柴油机机油压力低故障的危害,介绍了机油压力低故障产生的原因,针对故障原因提出了运用系统性方法判断处理机油压力低故障。     

矿山机电设备的故障检修与技术改造

由于矿山机电设备故障检修对矿山机电设备稳定运行具有重要作用,为此提出矿山机电设备的故障检修与技术改造。首先对矿山机电设备故障检修技术原理以及技术流程进行了概述,然后结合目前矿山机电设备故障检修技术现状,对其存在的问题进行了分析,最后针对问题对矿山机电设备故障检修技术中传感技术进行了改造,并引入了全生产保全技术提高故障检修质量,以此完成矿山机电设备的故障检修与技术改造。     

论矿山机械液压系统的故障及诊断

由于难以迅速发现矿山机械液压刺痛的故障及原因,需要对矿山机械液压系统常见故障及判断故障的方法进行分析。本文分析了矿山液压机械常见的故障,探讨了诊断故障的技术,以及进一步提升诊断故障的水平和质量。     

一起220kV输电线路故障及保护动作分析

通过对现场设备和线路的检查、故障动作报告、故障录波,分析了一起线路接地故障的类型、过程和产生原因,对故障存在的疑点进行了分析和排查,并对故障中继电保护的动作行为进行了分析,得出了结论及工作改进的方向。     

6kV同步电动机定子绕组故障修复

分析同步电机定子绕组匝间短路故障,采用甩掉故障线圈的局部修理方法对6kV同步电机定子绕组匝间故障进行修复,减少了故障停机时间,取得了良好效果。     

电感耦合等离子体原子发射光谱法测定钛及钛合金中铬和铜

铬、铜含量影响钛及钛合金组织结构和性能,须对其准确测定。采用硫酸-硝酸溶样体系溶解样品,选择Cr 267.716nm、Cu 327.393nm为分析线并采用两点校正法扣除背景,使用钛基体匹配的方法绘制校准曲线,使用电感耦合等离子体原子发射光谱法(ICP-AES)测定钛及钛合金中铬和铜。方法中各元素校准曲线线性良好,相关系数均大于0.999;检出限为0.04~6.0μg/g。按照实验方法测定3个钛及钛合金样品中铬和铜,结果的相对标准偏差(RSD,n=10)小于5%。按照实验方法测定5个钛合金标准物质中铬和铜,测定结果与认定值相吻合,分析误差在实验室允许的误差范围内。     

电感耦合等离子体原子发射光谱法测定钛及钛合金中铬和铜

铬、铜含量影响钛及钛合金组织结构和性能,须对其准确测定。采用硫酸-硝酸溶样体系溶解样品,选择Cr 267.716nm、Cu 327.393nm为分析线并采用两点校正法扣除背景,使用钛基体匹配的方法绘制校准曲线,使用电感耦合等离子体原子发射光谱法(ICP-AES)测定钛及钛合金中铬和铜。方法中各元素校准曲线线性良好,相关系数均大于0.999;检出限为0.04~6.0μg/g。按照实验方法测定3个钛及钛合金样品中铬和铜,结果的相对标准偏差(RSD,n=10)小于5%。按照实验方法测定5个钛合金标准物质中铬和铜,测定结果与认定值相吻合,分析误差在实验室允许的误差范围内。     

Comparison of high-performance liquid chromatographic serum profiles of humans and dogs

The sera of 30 healthy male beagles were analyzed by reversed-phase high-performance liquid chromatography. The profiles were compared with those obtained from the sera of 30 healthy human donors. The chromatograms of each group were very reproducible; however, there were characteristic differences between the two groups. The compounds observed in both the human and canine profiles were identified as creatinine, uric acid, tyrosine, hypoxanthine, xanthine, kynurenine, inosine and tryptophan. Compounds present only in the canine profiles were identified as cytindine, riboflavin and 5-methyl-cytidine. Compounds present only in the human profiles include uridine, guanosine, hippuric acid and the dietary dependent compounds theobromine and caffeine. The compounds present in both human and canine sera were quantitated and compared statistically. The amounts of these compounds were very similar, except for uric acid.     

Fabrication of Dense ZrO2/CNT Composites: Influence of Bead-Milling Treatment

Highly concentrated zirconia-carbon nanotube (CNT) water suspensions were prepared using an advanced milling technique. The bead-milling operation parameters were optimized for this system and used to prepare zirconia-stabilized water-based suspensions with different CNT contents. The effects of different milling conditions were studied. The particle dispersion was evaluated by SEM observations on dried suspension. Green’s density and SEM observations of compacts were used to follow the colloidal dispersability of the composites. Materials of tetragonal zirconia and CNTs were prepared with a high concentration of CNTs (1, 5, and 10 wt pct CNT). The homogeneous dispersion and distribution of the fibers in the bulk material after slip casting of the suspension were examined. The samples were sintered using spark plasma sintering (SPS) at 1473 K (1200 °C) and finally, fully dense materials were obtained. The mechanical properties were evaluated using the Vickers indentation technique.     

主流冷轧薄板工厂焊机机械结构研究与分析

研究与分析了当前主流的冷轧薄板工厂激光焊机及搭接焊机的机械结构,对其功能动作进行了简要描述,比较了它们的异同点。根据两年来的生产实践指出了其存在的问题及解决办法,并对未来焊机的选型提出了建议。     

Effects of ionizing radiation on incisor development of the prenatal mouse

The effects of 100 rad of X-irradiation of incisor development in CD1 mice were studied. 24 pregnant mice were irradiated on the 12th day post coitum and sacrificed from the 14th through the 20th gestational days. The 191 irradiated fetuses were smaller than those not irradiated, their crania and necks were malformed and their lower extremities were poorly developed. The developing incisors of the irradiated animals were retarded, the pulpal vessels were enlarged and the vessels walls did not maintain their structural integrity. The cells of the future pulp were necrotic, and the basement membranes appeared hyalinized. Ameloblasts and odontoblasts were abnormal in morphology and the formation of dental hard tissue was inhibited in places. Complete absence of incisor tooth germ was noted in three of the fetuses.     

抑制剂对超细WC-Co硬质合金性能的影响

采用高能球磨、真空烧结工艺制备超细WC-Co硬质合金。研究了抑制剂的预磨时间对WC-10Co硬质合金粒度及烧结试样性能的影响。对比了相同抑制剂配比对Co含量不同的硬质合金性能的影响以及稀土对硬质合金性能的影响。结果表明:通过对晶粒长大抑制剂的预磨,其粒度明显细化。加入预磨时间为120 h的抑制剂,WC-10Co硬质合金的平均粒度为0.3μm,硬度达到92.1 HRA。相同抑制剂配比的硬质合金,硬度和致密度随Co含量的降低而增大。稀土氧化物Y2O3的加入,有利于改善硬质合金的性能。     

Psychotherapy with a boy with depression following the death of his 2 brothers

The purpose of this study was to evaluate the relationship of alveolar bone morphology to tooth shape and form. 111 dry skulls were evaluated at Baylor College of Dentistry (Dallas, Texas). The skulls were arbitrarily divided into flat, scalloped and pronounced scalloped anatomic profiles according to alveolar bone anatomy. The number of buccal dehiscences and fenestrations was determined for each skull according to their anatomic morphotype. 10 skulls from each group were selected for bone height measurements. The measurements were made with a periodontal probe and ruler from the height of the interproximal bone to the buccal alveolar crest. Kodachrome slides were used to measure mesial-distal tooth width and length from ten skulls from each anatomic category. The average number of fenestrations for each group was 3.5. The mean number of dehiscences for flat and scalloped skulls was 0.5. The average number of dehiscences for pronounced scalloped was 1.2. There were no significant differences when the groups were compared. The mean distance from the height of the interdental bone to the alveolar crest was statistically significant when the groups were compared (flat 2.1 mm, scalloped 2.8 mm, pronounced 4.1 mm) (Tukey, p = 0.05). There were no significant differences when tooth shapes were compared with bone anatomy. Pronounced scalloped anatomic profiles were slightly narrower when compared with the other groups. The observations reported have treatment ramifications when patients with scalloped or pronounced scalloped morphotypes are being considered for dental implant placement.     

NiO-La2O3/γ-Al2O3催化剂中各组分间的相互作用

本文采用差热分析、X射线衍射、透射电镜和选区电子衍射对催化剂的物种情况及形貌加以研究 ,结合催化剂焙烧过程的相变情况 ,从而获得催化剂焙烧过程的化学反应情况。发现稀土助剂的加入使载体的晶体结构发生变化 ,从而使载体表面改性 ,抑制了 Ni Al2 O4的生成 ,提高了 Ni O的分散度。而且发现有 L a2 O2 CO3晶体存在于载体表面 ,L a2 O3以高度分散的状态存在     

电感耦合等离子体原子发射光谱法测定铝硅活塞合金中镧铈镨钕钇

采用硝酸和氢氟酸溶解样品,高氯酸冒烟赶氟避免生成氟化稀土沉淀,选择La 333.749nm、Ce 456.236nm、Pr 417.939nm、Nd 406.109nm及Y 371.030nm作为分析线,扣除背景点消除基体干扰,运用干扰系数法克服谱线间干扰,通过基体匹配法配制标准溶液系列消除基体效应的影响,使用电感耦合等离子体原子发射光谱法(ICP-AES)测定铝硅活塞合金中镧、铈、镨、钕和钇。结果表明:镧、铈的测定范围在0.01%~2.00%,镨、钕、钇的测定范围在0.005%~2.00%,校准曲线线性相关系数不小于0.9998。方法中各元素检出限为0.0003%~0.0018%。实验方法用于测定稀土铝合金合成试样中镧、铈、镨、钕和钇,结果的相对标准偏差(RSD,n=6)在0.50%~2.4%之间,加标回收率在94%~105%之间。实验方法用于含有稀土的铝合金标准样品中镧、铈、镨、钕和钇的测定,结果与电感耦合等离子体质谱法(ICP-MS)测定值相吻合,测定的稀土总量RE与认定值也相吻合。