DH型添加剂对水玻璃石英砂铸型与铸钢件界面烧结的影响

通过对水玻璃石英砂铸型与铸件之间界面层进行模拟,并对含DH型添加剂的界面层进行了烧结试验,研究了DH型添加剂对界面层烧结状态及力学性能的影响,并对铸钢件进行实际浇注.结果表明:在水玻璃石英砂中加入适量的DH型添加剂能提高型砂的耐火度,铸造过程中,易在铸型与铸件界面产生适度烧结的烧结层;DH型添加剂可提高浇注前水玻璃石英砂的初始强度以及浇注后界面烧结层的高温强度,降低界面烧结层冷却至室温的强度;并且,这种适度烧结的界面层具有高温塑性、室温脆性的特点.铸钢件浇注试验发现,添加DH型添加剂的水玻璃石英砂铸型和铸件界面产生的适度烧结的烧结层,易剥离,铸件表面光洁.     

Effect of moisture condensation on long-term reliability of crystalline silicon photovoltaic modules

Moisture condensation (MC) can occur in photovoltaic (PV) modules in hot and humid climates, and the resulting water droplets can cause more areas of corrosion. Therefore, in this study, MC history of PV modules exposed to Miami climate (FL, USA) has been derived employing corresponding meteorological data. The duration of MC versus temperature of PV module (T_module) was calculated over 1 year. Furthermore, five types of accelerated tests were conducted to develop a MC-induced degradation prediction model. The thermal activation energy, 0.4524 eV, was calculated. The Brunauer–Emmett–Teller (BET) model was used to predict the degradation rate. The accumulated degradation rate of a PV module exposed to the accelerated condition of MC was 1.45 times greater than that of damp heat (DH). The effect of encapsulant materials on the frequency of MC and accumulated degradation rate over 1 year were calculated in the Miami climate.     

牛肉水解液的制备及其抗氧化活性的研究

以牛肉为原料,采用四种蛋白酶进行酶解效果比较;通过预煮、微波和超声波三种预处理的观察,根据对酶解效果的影响来选择最好的预处理方法;并探讨了复合酶所制备的牛肉水解液抗氧化活性的效果。其结果表明:当采用复合酶酶解牛肉蛋白时,酶底物浓度比(E/S)为462 414 U/g、温度60℃、pH4．5、水解时间5h、底物浓度8%,抗氧化活性效果最好。     

基于WinCC6．0及ABPLC的可控硅整流监控系统

介绍一种应用于大电流整流系统的动态计算机监控系统,该系统以上位机的西门子WinCC6．0和下位机的ABSLC5／04系列PLC为核心进行动态监控。论述监控系统中上位机软件的设计与实现,以及人机界面动画的制作．介绍了上位机与下位机PLC的通信方式,阐述了镍、铜大电流整流系统的结构和特点。     

Preparation of sesame peptide and evaluation of antibacterial activity on typical pathogens

The antibacterial activity of sesame peptides on common pathogen was evaluated. The preparation of sesame protein hydrolysate was carried out in an enzymatic membrane reactor followed by fractionation through several ultrafiltration stages to obtain desired peptide fractions and evaluation of their antibacterial activity using two pathogens namely, Pseudomonas aeruginosa and Bacillus subtilis. Potential sesame peptides were characterized by mass spectroscopy (TOF-MS) followed by determination of their corresponding amino acid compositions. Sesame peptide fraction of molecular mass less than 1 kDa exhibited significant inhibition against growth of P. aeruginosa as compared to B. subtilis. Thus, these findings confirm the bacteriostatic effect of sesame peptide on growth of pathogens which can be exploited in bacteriostat composition.     

Efficient parity placement schemes for tolerating up to two disk failures in disk arrays

In order to achieve high reliability in disk array systems, two new schemes using dual parity placement, called DH1 (diagonal–horizontal) and DH2 schemes, are presented. Both DH schemes can tolerate up to two disk failures by using two types of parity information placed in the diagonal and the horizontal directions, respectively, in a matrix of disk partitions. DH1 scheme can reduce the occurrences of the bottleneck problem significantly because the parity blocks are evenly distributed throughout the disk array. DH2 scheme uses one more disk than DH1 scheme in order to store the horizontal parities, while the diagonal parities are placed in the same way as in DH1 scheme with a minor change. Even though both DH schemes use almost optimal disk space for storing the redundant information, the encoding algorithms for them are quite simple and efficient. Moreover, both DH schemes can recover rapidly from any two disk failures.     

波浪载荷作用下海洋平台用钢焊接接头的疲劳寿命预测

采用有限元建模分析初始裂纹形状对表面裂纹疲劳扩展过程中形状演化的影响,并基于BS 7910中FAD图的评定方法,预测了DH36焊接接头不同形状的初始裂纹在波浪载荷作用下的疲劳寿命。结果表明:c₀ /a ₀ 比值大的裂纹在扩展开始阶段均沿深度方向扩展,而长度方向上扩展极慢;而对于c0 /a0比值小的裂纹,在扩展过程中近似保持与初始相似的形状扩展。在波浪载荷的作用下,DH36焊接接头结构件能承受105 252个循环。     

正火型DH36高强度船板钢的开发

以C-Mn钢为基础,添加Nb、V、Ti等微合金元素复合合金化,采用控制轧制和正火热处理手段,开发出了综合性能优良的DH36高强度船板。经正火处理后,DH36钢板组织为均匀细小的铁素体和弥散分布的珠光体,带状组织减轻,消除了轧态钢板心部贝氏体组织,力学性能得到改善,最低抗拉强度为540 MPa,﹣40 ℃时冲击吸收能量＞150 J,均满足DH36船板对力学性能的要求。     

双指标评价核桃蛋白酶法增溶改性

为了提高脱脂核桃粉中核桃蛋白的溶解性,文中以水解度(DH)和可溶性固形物(SS)含量为指标,分别对木瓜蛋白酶、菠萝蛋白酶和风味蛋白酶的单酶水解、复合酶解效果进行分析。结果显示,复合酶解可以显著提高核桃蛋白的溶解性,适宜的酶组合是:木瓜蛋白酶1.2%+菠萝蛋白酶0.4%+风味蛋白酶0.2%,底物浓度12%,60℃下酶解3 h。所得速溶核桃粉的DH为5.57%,SS为48.33%,其中蛋白质质量分数83.26%,吸水性和吸油性分别提高了68.99%和52.48%,达到了核桃蛋白的增溶目的。此外,分析结果表明,酶解过程中DH和SS间存在极显著相关性,说明SS可以作为蛋白质酶解效果的评价指标,与DH一起对核桃蛋白酶解效果进行准确评价。     

大线能量焊接DH36钢焊接热影响区组织与性能研究

利用双丝埋弧焊接试验,对比分析了传统DH36钢和大线能量焊接DH36船板钢焊接热影响区的组织与性能。结果表明,利用新型的Ti处理技术生产的大线能量DH36钢母材具有良好的强韧性和大线能量焊接性。经大线能量(100 kJ/cm)焊接后,传统DH36钢焊接热影响区低温韧性显著降低,不能满足指标要求(34 J)。大线能量DH36船板钢在50 kJ/cm和100 kJ/cm热输入焊接时均表现出良好的低温韧性,-20℃冲击功大于100 J。同传统的DH36钢相比,大线能量DH36钢焊接接头出现了软化区,但接头强度并未显著下降。总体上大线能量焊接DH36钢优越性在于:大线能量焊接时,焊接热影响区主要得到大量交错排列的晶内针状铁素体组织,热影响区硬度降低,低温韧性显著提高。