Deformation behavior ofA6063 tube with initial thickness deviation in free hydraulic bulging

Experiment on seamless tubes of aluminum alloy A6063 with initial thickness deviation of 0-20% was conducted through a free hydraulic bulging with tube ends free. The influence of initial thickness deviation on the cross-section profile, thickness distribution, maximum internal pressure and maximum radial expansion was investigated. FEM simulation was also performed in order to examine and help explaining the experimental results. The results indicate that the internal pressure and maximum internal pressure appear to be little influenced by the initial thickness deviation, and that the cross-section profile of the bulged tube changes diversely and can not be a perfect circle. The results also suggest that the increase in initial thickness deviation may lead to a remarkable decrease in maximum radial expansion, and a rapid increase in thickness deviation and the center eccentricity of the inner and outer profiles.     

水压轴向柱塞泵配流盘最小水膜厚度的理论分析——结构参数的影响

最小水膜厚度是保证配流盘静压支承工作的基本条件，本文提出了最小水膜厚度应满足的基本要求，在两种不同的运动副表面粗糙度下，分别讨论了配流盘静压支承的主要结构参数对最小水膜厚度的影响，另一方面，分析结果又为结构参数的设计提供了参考依据。     

Diffusion bonding/superplastic forming of Ti-6Al-6V-2Sn/SUS 304 stainless steel/Ti-6Al-6V-2Sn

The superplasticity of the Ti- 6Al- 6V- 2Sn alloy for different temperatures was evaluated by single-sheet free blowing. The optimal superplastic temperature for the Ti- 6Al- 6V- 2Sn alloy was found to be 850 °C. Diffusion bonding of Ti- 6Al- 6V- 2Sn and 304 stainless steel was carried out in a vacuum. The interface of both bonded alloys was examined by EPMA. The concentration profile of Ni exhibited a peak at the interlayer and a valley adjacent it, whereas that of Cr exhibited a peak where Ni showed the valley. X- ray diffraction (XRD) analyses showed that the Fe ₂ Ti, NiTi, and CrMn Intermetallic compounds and the Cr element formed at the interface. The thickness profiles of the blown specimens were measured and compared with theoretical calculations.     

薄膜厚度对HfO2薄膜残余应力的影响

HfO2薄膜是用电子束蒸发方法制备的，利用ZYGO干涉仪测量了基片镀膜前后曲率半径的变化，计算了薄膜应力。对样品进行了XRD测试，讨论了膜厚对薄膜残余应力的影响。结果发现不同厚度HfO2薄膜的残余应力均为张应力，应力值随薄膜厚度的增加而减小，当薄膜厚度达到一定值后，应力值趋于稳定。从微观结构变化对实验结果进行了分析，发现微结构演变引起的本征应力变化是引起薄膜残余应力改变的主要因素。     

冷连轧机末机架AGC控制方式分析

介绍了冷连轧机末机架AGC控制3种方式的特点和适用范围，得出控制方式的选取须同时考虑轧制产品、轧机能力的发挥、板形、轧辊和后道工序的要求等多方面因素。     

一种智能纸张厚度计设计

根据纸张厚度测量控制系统的功能要求,应用β射线吸收原理,完成了一种智能纸张厚度计设计。它以MSP430FG479为微处理器,具有CAN和RS—485通信接口,具有自检测和自标定功能。给出了系统硬件实现方法,软件设计流程。经实验验证,检测精度达到0.1%以上。该设计方案,换用不同的放射源,可对各种纸和纸板的厚度进行检测,易于操作,工作稳定。     

电磁超声检测钢板厚度实验的参数优化

为提高电磁超声检测信号的信噪比,研究激励信号频率、脉宽及换能器提离距离对厚度测量结果的影响,搭建了电磁超声实验系统。该系统利用RITEC-SNAP 5000产生高能正弦波激励电磁超声换能器EMAT ( Electromagnetic Acoustic Trans-ducer),通过调节激励信号的频率、脉宽,改变提离距离来观测超声回波幅度的变化。实验结果表明：当激励频率和EMAT固有频率相同时其换能效率最高,采用6个周期的脉冲串时前后波包之间分界明显,为获得较大的回波幅度应尽可能减小提离距离。     

以临界屈曲应变为判断依据的非开挖内衬修复设计改进方法

《城镇排水管道非开挖修复更新工程技术规程》(CJJ/T 210-2014)选取管道的长期弹性模量EL进行内衬修复设计,并规定EL为短期弹性模量Es的0.5倍,但是对于这一做法的理论依据仍然存在较多质疑,也导致设计过于保守。据此考虑引入临界屈曲应变理论,提出以内衬的临界屈曲应变εr为破坏判据,并选取管道短期弹性模量Es进行设计的改进方法。研究表明,改进后的设计方法能够保证内衬设计在理论上的正确性,满足内衬的长期强度要求,减小大约21%的内衬设计壁厚,能够有效降低工程成本。     

Figure of merit for environmental SEM and its implications

A recently introduced figure of merit for environmental and low vacuum scanning electron microscopes has now been computed in the full operational pressure range for one commercial instrument. The direct simulation Monte Carlo method has been used in lieu of experimental measurements. The theory of this figure of merit is further consolidated. It is shown that a thin pressure limiting aperture can indeed be used as an optimum reference system for all instruments employing differential pumping in the transfer of an electron beam from high vacuum to high pressure. The implications of the results obtained are discussed both in relation to existing commercial instruments and associated literature to pave the way for future progress in the field.     

Ketamine effects on the urogenital system--changes in the urinary bladder and sperm motility

Different doses of ketamine (10 mg/kg, 20 mg/kg, 30 mg/kg, 40 mg/kg, 50 mg/kg, and 60 mg/kg) were injected i.p. (I.P.), respectively, to male ICR mice to determine the optimal dosage for chronic administration. At and above 40 mg/kg I.P. injection, mice had almost no hindlimb movement during swimming test. Subsequently, 30 mg/kg was used as the dose for the study in the toxicity of long-term ketamine administration on urinary bladder and sperm motility. The treatment group were subdivided into two (n = 10 each group); one received daily ketamine treatment i.p. for 3 months and another group for 6 months. Corresponding number of mice in control groups (n = 5 each group) received saline injection instead of ketamine. Terminal dUTP nick and labeling (TUNEL) study and Sirius red staining were carried out on the sectioned slides of the urinary bladders to study the degree of apoptosis in both epithelium and muscular layers of the urinary bladder and the relative thickness of the muscular layers in this organ was also computed. Apoptosis in the bladder epithelium was observed initially in the 3-month ketamine treated mice and the number of apoptotic cells was significantly different (P < 0.05) between the 3-month and 6-month ketamine treated mice and the control. The relative thickness of muscular layers in the bladder wall also decreased significantly (P < 0.05) when the 6-month treated mice and the control were compared. Sirius red staining revealed increase of collagen in the urinary bladder of the treated mice, most evidently 6 months after ketamine treatment. In addition, the sperm motility was studied and there was a statistically significant difference between the control and ketamine treated groups in the percentages of sperms which were motile (P < 0.05). This suggested that the chronic administration of ketamine affected the genital system as well.