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41.
介绍了钢丝绳探伤仪漏磁检测原理,并使用有限元分析方法分析了传感器零件的材料、钢丝绳的提离距离及断丝根数等对基于漏磁原理的钢丝绳探伤仪检测结果的影响。分析结果表明,提离距离、断丝根数等因素对探伤仪检测结果影响较大,断丝角度、深度等因素影响较小。  相似文献   
42.
本文主要对计算机硬盘数据丢失的原因、恢复软件的应用方法进行分析。  相似文献   
43.
介绍一种使用WinHex软件恢复找回u盘文件的方法,利用这种方法,u盘使用者通过一些简单的操作步骤,可尝试对偶尔出现的文件误删、误格式化操作进行恢复,挽回损失。  相似文献   
44.
该研究以吐鲁番地区无核白葡萄为试验材料,在25 ℃常温和30 ℃热风干燥后,取失水25%、50%时褐变和未褐变的样品。利用转录组测序技术筛选出膜脂降解代谢相关的关键基因,并利用实时荧光定量PCR技术对其进行验证,研究结果显示,转录组测序共获得了11.63亿的clean data,当无核白失水50%时未褐变与褐变的相比,在快速脱水组筛选出718个差异表达基因,慢速脱水组2 259个。将上述基因进行GO功能富集和KEGG富集分析后,筛选出43个膜脂代谢相关的差异基因,归类于5种代谢途径。从已获得的差异基因中最终筛选出乙醛脱氢酶7B4(Aldehyde Dehydrogenase7B4,ALDH7B4)、双半乳糖甘油二酯合成酶1(Digalactose Diglycerol Synthetase1,DGD1)、脂氧合酶(Lipoxygenase,LOX)、磷脂磷酸水解酶2(Lipid Phosphate Phosphatase2,LPP2)、二酰基甘油激酶5(Diacylglycerol Kinase5,DGK5)、非特异性磷脂酶C4(Non-specific Phospholipase C4,NPC4)、磷脂酶Dα1(Phospholipase Dα1,PLDα1)7个膜脂代谢相关的关键基因,经qRT-PCR验证,基因表达趋势与转录组测序结果基本一致。结果表明,膜脂降解代谢相关基因表达量变化对无核白脱水褐变有一定影响。  相似文献   
45.
Precise adjustment of the pore size, damage repair, and efficient cleaning is all challenges for the wider application of inorganic membranes. This study reports a simple strategy of combining dry-wet spinning and electrosynthesis to fabricate stainless-steel metal–organic framework composite membranes characterized by customizable pore sizes, targeted reparability, and high catalytic activity for membrane cleaning. The membrane pore size can be precisely customized in the range of 14–212 nm at nanoscale, and damaged membranes can be repaired by targeted treatment in 120 s. In addition, advanced oxidation processes can be used to quickly clean the membrane and achieve 98% flux recovery. The synergistic actions of the membrane matrix and the selective layer increase the adsorption energy of active sites to oxidant, shorten the electron transfer cycle, and enhance the overall catalytic performance. This study can provide a new direction for the development of advanced membranes for water purification and high-efficiency membrane cleaning methods.  相似文献   
46.
This paper proposes an improved sine–cosine algorithm (ISCA) based 2-DOF-PID controller for load frequency control. A three-area test system is built for study, while some physical constraints (nonlinearities) are considered for the investigation of a realistic power system. The proposed method is used as the parameter optimizer of the LFC controller in different scenarios. The 2-DOF-PID controllers are used because of their capability of fast disturbance rejection without significant increase of overshoot in set-point tracking. The 2-DOF-PID controllers’ efficacy is observed by examining the responses with the outcomes obtained with PID and FOPID controllers. The simulation results with the suggested scheme are correlated with some of the existing algorithms, such as SCA, SSA, ALO, and PSO in three different scenarios, i.e., a disturbance in two areas, in three areas, and in the presence of physical constraints. In addition, the study is extended to a four-area power system. Statistical analysis is performed using the Wilcoxon Sign Rank Test (WSRT) on 20 independent runs. This confirms the supremacy of the proposed method.  相似文献   
47.
采用交联改性的方法对较低分子量的乙烯基硅橡胶进行了改性研究,制备了高通量的富氧膜,结合单因素实验法和Design-expert正交实验设计,考察了原料配比、交联反应时间、固化温度和固化时间等因素对富氧膜性能的影响,确定了最佳富氧性能膜的制备条件:原料配比4.3,反应时间2.15h,固化温度86.25℃,固化时间1.75h;获得了富氧浓度为28.68%,透气量为4696.33 barrer的富氧膜,该膜的富氧浓度与常规商品化膜相当,透气量为常规商品化膜的2~4倍,有应用于发动机富氧进气系统的前景。通过扫描电镜检测、机械性能检测等手段对复合膜进行了进一步表征。  相似文献   
48.
In the present work, the influence of process parameters such as welding current (I), welding speed (S), and flux coating density (F) on different aspects of weld bead geometry for example depth of penetration (DOP), bead width (BW), depth to width ratio (D/W), and weld fusion zone area (WA) were investigated by using the central composite design (CCD). 9–12% Cr ferritic stainless steel (FSS) plates were welded using A-TIG welding. It was observed that all input variables have a direct influence on the DOP, BW, and D/W. However, flux coating density has no significant effect on WA. Mathematical models were generated from the obtained responses to predict the weld bead geometry. An optimized DOP, BW, D/W, and WA of 6.95?mm, 8.76?mm, 0.80, and 41.99?mm2, respectively, were predicted at the welding current of 213.78 A, the welding speed of 96.22?mm/min, and the flux coating density of 1.99?mg/cm2. Conformity test was done to check the practicability of the developed models. The conformity test results were in good agreement with the predicted values. Arc constriction and reversal in Marangoni convection were considered as major mechanisms for the deep and narrow weld bead during A-TIG welding.  相似文献   
49.
Product recovery involves the recovery of materials and components from returned or end-of-life products. Disassembly, an element of product recovery, is the systematic separation of an assembly into its components, subassemblies or other groupings. Stricter environmental regulations together with dramatic decrease in natural resources and landfills have increased the importance of disassembly as all product recovery options require some level of disassembly. Due to changes made during the lifetime of a product by customers or service personnel, the number and the version of components prior to disassembly is unknown. Customers may also discriminate between and demand different versions of components. The existence of non-functional components further adds to the uncertainty associated with disassembly yield. Sensors implanted into products during their production can address this uncertainty by providing information on the number, condition and version of components prior to disassembly. In this study, we evaluate the impact of sensor embedded products (SEPs) on the various performance measures of a washing machine (WM) disassembly line controlled by a multi-kanban system, which takes into consideration the highly stochastic behavior of the line while managing material and kanban flows. First, separate design of experiments studies based on orthogonal arrays are performed for conventional products and SEPs. In order to observe the response of each experiment, detailed discrete event simulation (DES) models for both types of products are developed considering the precedence relationships among the components of a WM. Then, pair-wise t-tests are conducted to compare the two cases based on different performance measures. According to the results, SEPs provide significant reductions in all costs (viz., backorder, holding, disassembly, disposal, testing and transportation) while increasing revenue and profit.  相似文献   
50.
湿法相分离不对称超滤膜形成机理   总被引:1,自引:0,他引:1  
本文选择了憎水的极怀非普质子性聚砜和亲水的极性质子怀聚砜酰胺两种膜材料,从铸膜液组成和凝胶过程两方面,用气相色谱和高效液相色谱研究了表征膜材料-溶剂-添加剂-水作用力的混合自由焓,平衡分配常数,及其与膜性能,不同溶剂特性粘度,雾点值和溶解度参数的关系,提出了铸膜液中有机溶剂的作用机理,及不对称超滤膜形成的一些规律。  相似文献   
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