International round Robin test for mechanical properties of BSCCO-2223 superconductive tapes at room temperature

International RRT was carried out in order to establish the test method for mechanical properties of commercial BSCCO superconductive tapes under cooperation of seven research laboratories. From the stress versus strain curve, the following quantities were evaluated; modulus of elasticity, 0.2% proof strength, fracture strength and stresses at fixed strains. The scatter of measured values was analyzed by evaluating the relative standard uncertainty (RSU), which is the standard uncertainty divided by the average. The expected value of RSU for N = 3 was derived for each mechanical quantities. In order to make clear the major contribution to the scatterings, the F test was applied. The major source of RSU’s was attributed mostly to the influence of inter-laboratory scattering.     

Characterizing acrylic foam pressure sensitive adhesive tapes for structural glazing applications-Part II: Creep rupture results

The objective of this study was to determine relevant, primary mechanical characteristics of high-performance acrylic foam pressure sensitive adhesive (PSA) tapes, an alternate fastening method for structural glazing applications. Traditional fastening methods for structural glazing typically employ structural silicones and, consequently, relevant ASTM test standards and specifications appear to be more appropriate for silicones and similar products that exhibit limited time dependence. This study was aimed at characterizing and evaluating acrylic foam PSA tapes for structural glazing applications, and because of their time dependence, viscoelastic characterization was included. Since there may be significant differences in the viscoelastic responses of acrylic foam PSA tapes and silicones, the study may account for important differences between acrylics and silicones in structural glazing applications. The acrylic foam PSA used in the study was 3M™ VHB™ Tape G23F. For comparison, parallel ramp-to-fail tests were also conducted on 3 silicones: two one-part and one two-part compositions. Mechanical characteristics determined for the VHB™ Tape included the viscoelastic properties over a range of temperatures and test rates. Mechanical characteristics available in the literature were assumed for the silicones and confirm their limited time dependence. Ramp-to-fail strength data (Part I paper) and creep rupture (accompanying paper, Part II paper) data was collected for the VHB™ Tape and the silicones. Using the time–temperature superposition principle, master curves of VHB™ Tape storage and loss moduli in shear and tension were developed with data from a dynamic mechanical analyzer (DMA). The thermal shift factors obtained from these constitutive tests were successfully applied to the VHB™ Tape creep rupture and ramp-to-fail data collected at 23, 40, and 60 °C, resulting in master curves of ramp-to-fail strength (in Part I of paper) and creep rupture durability (Part II paper) in shear and tension.     

新型输送带毛边切割装置的应用研究

介绍了一种新型的输送带毛边切割装置的应用,该装置可实现对带式输送机报废输送带的回收再利用。输送带在切割毛边后不会发生跑偏现象,保持了原有输送带的抗拉强度和性能,可满足使用要求。     

宁波梅山岛商务中心单元式玻璃幕墙防水技术

宁波梅山岛商务中心单元式玻璃幕墙通过工字插芯实现单元板块组件的连接,并选择合适的EPDM胶条进行多道密封设计,幕墙板块通过可靠的组角技术提高板块强度,同时对开启扇与百叶进行严密的防水设计,最终达到完美的防水效果.     

胶带用8011-O铝箔退火工艺研究

采用拉伸试验和表面润湿试验测定,分析了三种不同生产工艺方案生产的8011-O铝箔的力学性能和表面润湿性,确定了合理的8011-O态胶带箔生产工艺。结果表明,采用铸轧坯料可以生产高质量胶带用铝箔,其最佳成品退火工艺为200℃12 h+250℃30 h,同时通过调整除油段的温度和除油时间段的分布,获得高表面质量的胶带箔。     

Estimation of uncertainty with the modulus of elasticity measured by means of tensile test for BSCCO tapes

The international round robin test (RRT) was conducted in order to establish the international standard for the tensile test method for BSCCO-2223 tape shaped wires. The measurands of mechanical properties were statistically analyzed to estimate their standard uncertainties and their correlation among laboratories. Consequently the large variance was observed with the modulus of elasticity determined from the initial loading curve. The reason has been examined by estimating type B uncertainties causing at every step of the experimental procedure. With respect to the modulus of elasticity, the grand intra-lab average of relative standard uncertainty (RSU) obtained from the RRT coincided roughly with that derived by means of type B evaluation. Thus it is emphasized that the type B evaluation is very effective tool for expecting the uncertainties of the observations like the modulus of elasticity. On the other hand, the grand over-all RSU was larger than the grand intra-lab one. The combined standard uncertainties were calculated by changing the strain rate, but kept other parameters constant. In order to suppress the influence from the strain rate to the variance, it has been recommended that the strain rate shall be regulated less than 2 × 10⁻⁴ 1/s in the tensile test method.     

以TEA和PAA为分散剂的水基流延SDC

分别以三乙醇胺(TEA)和聚丙烯酸(PAA)为分散剂,用水基流延法制备Sm2O3掺杂的CeO2(Ce0.8Sm0.2O1.9,SDC)陶瓷,研究了pH值对SDCζ电位的影响,分析了SDC生坯的物理性能。TEA和PAA分散的SDC,最大ζ电位绝对值分别为62 mV和49 mV,TEA分散的生坯在基板上铺展得更好,外观更均一,显微结构更均匀、致密,TEA和PAA分散的生坯,相对密度分别为51.7%和46.2%,极限抗拉强度分别为1.25 MPa和1.06 MPa。TEA是SDC陶瓷较好的水基流延分散剂。     

高速无梭织带机在玻纤织带上的应用

介绍了玻纤高速织带的生产工艺流程；详细介绍了高速无梭织带机的主要织带参数、工作流程及开口机构、送纬机构、锁边机构、打纬机构及卷取机构等主要五大机构的工作原理；对高速无梭织带机与普通有梭织带机进行了产量比较；详细分析了应用高速无梭织带机时需注意的问题，如送纬速度的选择、玻纤单丝直径的选择、玻纤浸润剂的选用、室内温湿度的控制、锁边线的选择、织带机的调试等诸多问题。     

铁磁性基底对第二代高温超导带材交流损耗的影响

对采用不同工艺制备的不同基底的第二代高温超导带材的交流损耗进行了测量,并研究了铁磁性基底对其交流损耗的影响。结果表明,电流较小时,具有铁磁性基底的带材损耗要远大于Norris临界态模型计算值,并且制备工艺的不同也会对带材交流损耗产生一定影响。考虑铁磁基底的铁磁损耗,将铁磁损耗和磁滞损耗进行相加后,实验测量值和Norris模型很好地吻合,说明铁磁基底高温超导带材的损耗具有很大的影响。实验研究结果表明,对于采用PLD工艺制备的YBCO超导带材,基底没有磁性,带材交流损耗不受铁磁损耗影响,而采用IBAD工艺制备的哈氏合金基底YBCO带材和采用RABiTS工艺制备的Ni-W基底YBCO带材,由于基底具有磁性,在通电电流较小时,带材交流损耗不仅要考虑超导体的磁滞损耗,还要考虑基底铁磁损耗的影响。     

生瓷带冲孔工艺设备应用及发展趋势

主要对(应用于LTCC和HTCC)生瓷带冲孔工艺的特性以及几种主要的冲孔设备应用的现状和发展趋势进行了论述。且分析了生瓷带冲孔设备应该具备的高位置精度、边缘精度和高冲孔速度。同时研究了气动冲孔机和激光冲孔机在生瓷带冲孔工艺中的应用和发展趋势。