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741.
针对电梯钢丝绳运行状态存在的在线监测困难、故障检测不准确的问题,搭建模拟电梯钢丝绳运行的实验台,通过设计励磁器、检测器结构,设计基于LabVIEW的电梯钢丝绳状态监测多通道数据采集系统。对钢丝绳断丝、磨损等常见故障信号进行多通道采集并实时显示波形图、存储数据以便进行进一步分析。试验表明,该系统可以多通道采集钢丝绳的漏磁信号,提高了信号的空间分辨率,能准确地检测不同程度的钢丝绳断丝磨损等故障信号,并将采集到的数据以TDMS文件的形式保存下来进行波形回放,进一步定量分析故障部位及程度。 相似文献
742.
Conventionally manufactured 35CrMo cold heading steel must undergo spheroidization annealing before the cold heading process. In this paper, different types of deformation processes with various controlled cooling periods were operated to achieve on-line spheroidal cementite using the Gleeble-3500 simulation technique. According to the measured dynamic ferrite transformation temperature (Ad3), the deformation could be divided into two types: low temperature deformation at 810 and 780℃; “deformation-induced ferrite transformation” (DIFT) deformation at 750 and 720℃. Compared with the low temperature deformation, the DIFT deformation followed by accelerated cooling to 680℃ is beneficial for the formation of spheroidal cementite. Samples subjected to both the low-temperature deformation and DIFT deformation can obtain granular bainite by accelerated cooling to 640℃; the latter may contribute to the formation of a fine dispersion of secondary constituents. Granular bainite can transform into globular pearlite rapidly during subcritical annealing, and the more the disperse phase, the more homogeneously distributed globular cementite can be obtained. 相似文献
743.
Changchun Wang Yonghui Deng Wuli Yang Shoukuang Fu 《复旦学报(自然科学版)》2005,44(5):642-643
1 Introduction Because of the wide applications in the area of biomedical and biotechnological fields, a great efforts have been done to fabricate different kinds of microspheres with tailored structural and surface properties over the last decade~([1]). Among them, stimuli responsive microspheres are microspheres that show ability to change their physical-chemical properties and colloidal properties in response to environmental stimuli such as changes of temperature, pH, chemicals, light, ele… 相似文献
744.
Two new 2-substituted thiazolidine-4(R)-carboxylic acids (TCAs), 2-glusosaminal-TCA (GIcNH2Cys) and 2-N-acetyl-glueosanlinal-TCA (GlcNAeCys), were synthesized. Their protective effects against liver toxicity induced by acetaminophen (APAP) were investigated in a mice model. The resuits demonstrate that administration of TCAs ( i. p. , 800 mg/kg) 30 min after APAP challenge efficiently decrease ALF, AST, and LDH levels in liver. GlcNAcCys shows the best proteetive eftects, decreasing ALT, AST and LDH levels to 63%, 18.4% and 37% of the APAP group respectively. Comparison with the control showed that APAP greatly decreases total sulfhydlyl (T-SH) levels (43%), non-protein hound sulfhydryl (NP-SH) levels (50%) and total antioxidative capabilities (57%) in the liver 24 hr after challenge. TCAs treatments 30min after APAP challenge significantly elevate sulfhydryl levels and total antioxidative capabilities. APAP administration also markedly (P 〈 0.05) increases liver lipid peroxidation to 1.65 and 1.17 times that of the control 4 hr and 24 hr after APAP administration respectively. TCAs treatments can inhibit lipid peroxidation as measured by decreased malondialdehyde (MDA) contents in liver. The histopathological results also further confirm the hepatoprotective effects of TCAs. In conclusion, our data show that TCAs, GleNAcCys particularly, have hepatoprotective anti antioxidant etfects. 相似文献
745.
使用Fluent对某钢厂KR脱硫搅拌工艺过程进行数值模拟,研究桨叶长度、搅拌头插入深度及转速对搅拌效果的影响。结果表明,尺寸为2B=1 300mm的长浆叶搅拌头搅拌效果较好,搅拌头插入深度为液面下800mm左右较为适宜,搅拌头转速以80~120r/min为宜。 相似文献
746.
基于TFIDF(Term Frequency Inverse Document Frequency)算法,结合用户通话圈运用呼叫指纹方法分析用户的交往圈、呼叫特征、短信特征、位置特征、客服特征、终端特征等特征,构建家庭关系识别模型,进而挖掘家庭关联关系的手机与固话在呼叫圈相似度、平均每天通话次数、平均每次通话时长等变量上的相关性,为发现手机号码与家庭固定电话之间的关联关系提供了有效的技术手段,并有效地应用于固移捆绑套餐和可选套餐的目标客户的识别。从实际营销效果来看,该模型的使用有利于帮助市场营销人员快速、方便、有效地开展融合套餐的销售,在降低营销成本的同时提高了营销效果。 相似文献
747.
将模糊可靠性理论应用于提升机主轴的疲劳强度设计中,建立了提升机主轴疲劳强度的模糊可靠性设计数学模型,介绍了它的设计方法,并给出了算例。算例中通过分析比较,说明了模糊可靠性设计的合理性和先进性。 相似文献
748.
无线传感器网络中间件技术 总被引:4,自引:0,他引:4
目前,面向应用的无线传感器网络普遍缺乏统一开放的软件体系架构和高效的开发接口,因而阻碍了其进一步发展和应用.针对无线传感器网络特点,全面介绍无线传感器网络中间件软件的概念、设计需求与关键技术,并在此基础上分析其体系结构.同时,提出无线多媒体传感器网络中间件的概念,并构建一种基于Agent的无线多媒体传感器网络中间件体系. 相似文献
749.
Electrical conductivity changes of bulk tin and Sn-3.0Ag-0.5Cu in bulk and in joints during isothermal aging 下载免费PDF全文
The changes of electrical conductivity (resistance) between Sn-3.0Ag-0.5Cu solder joints and printed circuit board (PCB) assembly during aging at 125℃ were investigated by the four-point probe technique. The microstructural characterizations of interfacial layers between the solder matrix and the substrate were examined by optical microscopy and scanning electronic microscopy. Different types of specimens were designed to consider several factors. The experimental results indicate that electrical conductivities (resistances) and residual shear strengths of the solder joint specimens significantly decrease after 1000 h during isothermal aging. Microcracks generate in the solder matrix at the first 250 h. Besides, the evolutions of microstructural characterizations at the interface and the matrix of solder joints were noted in this research. 相似文献
750.
以卫生纸厂初级污泥作为生物质原料,采用同步糖化发酵法生产燃料乙醇,对其工艺条件进行了优化,并考察了3种非离子表面活性剂(Tween-20、Tween-60、Tween-80)对造纸污泥同步糖化发酵的促进效果.结果表明:合适的工艺条件为反应温度36℃、底物质量浓度100 g/L、酵母接种量6%(体积分数)、纤维素酶用量25 FPU/g;Tween-20能显著促进造纸污泥的同步糖化发酵,添加0.2%的Tween-20时,乙醇产率提高14%;上述工艺条件下反应48 h的乙醇质量浓度达19.5 g/L,是理论值的63.9%.对同步糖化发酵前后污泥及发酵液的主要化学成分进行分析,发现大量纤维素已糖化发酵成乙醇,仅少量半纤维素发生水解,水解产物木糖不能被酵母有效利用发酵成乙醇.扫描电镜分析显示造纸污泥经同步糖化发酵后,长条状的纤维大多被破坏,同时出现了大量椭球状的酵母细胞. 相似文献