PCD拉丝模坯材料微结构对比分析研究

文章对国内外典型PCD拉丝模坯材料进行了SEM观察、EDS能谱分析和XRD物相分析,研究了国内外产品在微观结构和成分上的差距,结合拉丝模实际拉丝效果探讨了其微观结构与性能的关系,并提出为开发国产高档PCD拉丝模坯材料,应注意尽量减小其晶粒尺寸、优化粘结剂组分以及提高粘结剂的分布均匀性。     

纺粘法非织造布双狭缝正压牵伸器应用分析

概述了纺粘法非织造布牵伸器的分类,介绍了双狭缝正压气流牵伸器的设计制造,说明了其使用优势及维护保养。     

基于DYNAFORM软件的水壶拉伸模具改进

水壶拉伸模由于结构复杂,在模具设计时往往需要反复试模,成本较高,采用计算机模拟冲压过程可以减少试模次数。水壶冲压件冲压时容易在悬空区起皱（即内皱）,为此,根据产品形状特点,采用特殊形状压边圈的方法来消除内皱,并用DYNAFORM软件对其效果进行数值模拟,结果显示冲压产品中没有出现内皱,为曲面拉深模具设计提供参考。图8参8     

Structure and properties of MDO stretched polypropylene

Two polypropylene cast films of different crystalline structures (one with coexisting small rows of lamellae and spherulites and the other with only a spherulitic structure) were prepared by extrusion. The produced cast films were uniaxially hot drawn at T = 120 °C using a machine direction orientation (MDO) unit and the changes in structure and morphology were examined and related to barrier as well as tear and puncture properties. Structural changes in terms of the degree of crystallinity and crystal size distribution, orientation of the amorphous and crystalline phases, and the deformation behavior at the crystal lattice and lamellae scales were investigated using differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR), wide angle X-ray diffraction (WAXD), and small angle X-ray scattering (SAXS), respectively. A significant effect of the original crystal morphology on the alignment of the amorphous and crystalline phases was observed from FTIR and WAXD. The results also revealed that the deformation behavior of the crystal structure was dependent on the draw ratio (DR). Our findings showed that by increasing DR the crystal lamellae first broke up and oriented along the drawing direction and then, at large DR, they were deformed and created a fibrillar structure. Morphological pictograms illustrating the effects of original morphology and draw ratio on the stretched film microstructure are proposed. The tear resistance along the machine direction (MD) decreased significantly with increasing DR whereas the puncture resistance increased drastically. Finally, the oxygen transmission rate (OTR) of the MDO stretched films could be correlated with the orientation parameters as well as the β-relaxation peak magnitude of the amorphous tie chains.     

谈计算机技术与建筑的关系

从建筑画的发展谈起,阐述了计算机辅助建筑设计的发展及其在建筑画表达方面的巨大影响和不足之处。并结合全球能源紧缺的现实,论述了计算机技术在建筑能耗模拟和工况运行监测等新领域的应用情况。     

高浓度铜拉丝废液处理试验研究

针对铜拉丝厂的铜拉丝废液浓度高、难处理的特点,研究开发了一条切实可行的工艺路线:除油→除铜→混凝→回用、生化处理或并人污水处理厂.得出了最佳工艺条件:破乳剂投加量400 mg/L,除铜剂投加量1 500mg/L,PAC 50 mg/L+PAM 0.5 ms/L,在适宜工艺条件下,废水的CODCr浊度、总铜和油分的去除率分别达90.5%、99.5%、99.6%、99.9%.最后估算了该工艺的药剂成本为4元/t,是经济可行的.     

关于我国碳纤维用聚丙烯腈原丝质量的若干认识

分析了我国碳纤维用聚丙烯腈原丝质量欠佳的原因,主要是生产工艺包括聚丙烯腈的聚合方法、聚合物相对分子质量及其分散性、纺丝原液的纯度及其流变性、纺丝方法以及拉伸工艺等存在弊端。指出我国碳纤维用聚丙烯腈原丝生产过程中,应加强对聚合物及纺丝原液的质量控制,开发干-湿法工艺,从而提高原丝质量。     

求解带AGV柔性作业车间调度问题的改进灰狼算法

针对带AGV的柔性作业车间调度问题,以最小化完工时间为目标,考虑AGV在装载站、机器、卸载站之间的有效负载时间和空载时间,构建了数学规划模型。其次,提出一种有效的灰狼算法进行求解,基于该问题特征,设计机器选择、工序排序和AGV搬运的3段编码,有效地保证每个个体均可产生可行解;灰狼算法中改进了关键参数a和E设定方式,有效平衡了算法的勘探能力和局部搜索能力;为进一步提升算法跳出局部最优解的能力,该算法融合了领域搜索等方法。最后,案例测试结果表明,改进灰狼算法在求解带AGV柔性作业车间调度问题中具有优越的性能。     

DC06超深冲连退板表面缺陷形貌分类及控制措施

DC06超深冲连退板因表面硬度极低,表面缺陷发生率比普通钢种高出几倍。其缺陷形成原因涉及炼钢、热轧、冷轧、连退等多道工序,且表面缺陷形貌表现各异。目前,在缺陷成因分析上耗时耗力,改善措施更是严重滞后。为此,在某产线收集了DC06超深冲带钢表面缺陷,根据缺陷形貌进行分类分析,明确了4类典型缺陷产生的工序,并提出了控制措施,使该产品的表面缺陷率降低了50%以上。     

All Night Long: The Architectural Jazz of the Texas Rangers

In the mid-1950s, a group of young faculty at the University of Texas School of Architecture in Austin - aka the Texas Rangers - entertained themselves with weekly sessions of a sophisticated, collective drawing game, ‘Dot-the-Dot’, in which there was an emphasis on inventive fluency in hand drawing as well as an innate knowledge of historic European city plans. What happened when Mark Morris , Visiting Associate Professor at Cornell University, decided in a design studio to ask present-day students to revive the game?