新型可见光固化树脂

针对一些过氧化物固化不能满足特殊的施工环境,以及紫外光固化存在对人体有害、应用范围窄、厚膜固化性不好等缺点,开发了1种利用可见光光源进行固化的变性乙烯基酯树脂(VLC树脂),通过测定其黏度、比重、酸价、力学性能、Tg、热变形温度、积层板在一定浓度的酸、碱、水、有机溶剂等介质里面的强度保持率,分别对树脂液态特性、树脂浇铸体及积层板的力学性能以及积层板的耐腐蚀性能进行了表征,通过与一般的过氧化物固化的乙烯基酯树脂的浇铸体及积层板性能比较,可以看出:可见光固化与常见的过氧化物固化相比,性能相当甚至更佳,并且可见光固化速度极快,苯乙烯挥发极少,作业简单,无须加促进剂和固化剂,无须繁琐的搅拌和脱泡过程,提高生产效率的同时,大幅度降低施工成本。     

Al_4O_4C的碳热还原合成及其反应动力学

以氧化铝(Al2O3)和石墨(C)为原料,采用碳热还原工艺合成铝氧碳(Al4O4C),借助于X射线衍射仪和场发射扫描电子显微镜研究了加热温度和保温时间对合成铝氧碳(Al4O4C)的影响。结果表明:提高加热温度,可加快Al2O3和C反应生成Al4O4C的反应速率;延长保温时间可增大Al2O3和C反应生成Al4O4C的反应程度。在反应初期主要为固-固反应,Al2O3和C直接接触反应生成Al4O4C和一氧化碳(CO);后期主要为气-固反应,Al2O3和CO气体反应生成Al4O4C和二氧化碳(CO2)。计算得到气-固反应的频率因子和活化能分别为338.66和264.19kJ/mol。     

Formation Reaction of ZrO2 Scatterers in ZrF4-Based Fluoride Fibers

This paper clarifies the formation reaction of ZrO₂ crystals which appear as extrinsic scatterers in fluoride fibers. EPMA analysis indicates that BaO exists at grain boundaries of BaF₂ purified by sublimation. BaO reacts with ZrF₄ to form ZrO₂ at 600°C during a glass-melting process. The ZrO₂ formation reaction is influenced by H₂O. Ba(OH)₂, which is formed by the reaction between BaO and water vapor, melts at 370° to 420°C and reacts with ZrF₄ to form ZrO₂ at 450° to 520°C. When low-oxide-content BaF₂ is used for fiber preparation, scatterers significantly decrease.     

Precise Determination of the 3CaO·SiO2 Cells and Interpretation of Their X-Ray Diffraction Patterns

The cell dimensions of pure triclinic 3CaO·SiO₂ and monoclinic 3CaO·SiO₂ solid solution (54CaO·16SiO₂·Al₂O₃·MgO) were determined and the powder diffraction patterns were indexed by the method of precise measurement of the spacings. The lattice constants are expressed in terms of triclinic or monoclinic cells corresponding to pseudo-orthorhombic cells derived from Jeffery's trigonal cell. The apparent lattice constants for pure 3CaO·SiO₂ are a = 12.195 a.u., b = 7.104 au., c = 25.096 a.u., α= 90°, β= 89°44'γ= 89°44'; for 54CaO·16SiO₂.-Al₂O₃MgO, a = 12.246 a.u., b = 7.045 a.u., c = 24.985 a.u., β= 90°04'. Precise lattice constants of Jeffery's monoclinic lattice for 54CaO.-16SiO₂-Al₂O₃·MgO are derived as a = 33.091 a.u., b = 7.045 a.u., c = 18.546 a.u., β= 94°08'. High-temperature X-ray patterns showed that pure triclinic 3CaO·SiO₂ transformed to a monoclinic form at about 920°C. and then to a trigonal form at about 970°C. Monoclinic 54CaO.16SiO₂·Al₂O₃–MgO transformed to trigonal at about 830°C. These transitions were reversible and reproducible and were accompanied by only slight deformation of the structure forms.     

‘Jishu Kanri’ activities in the Japanese steel industry Small group activities being promoted by the industry as a whole

The group activities called ‘ Jishu Kanri ’ by foremen and workers in the forefront of production has been actively promoted in the Japanese Steel Industry by establishing a committee for ’ Jishu Kanri’ activities in the Japan Iron and Steel Federation, with the positive cooperation of its member companies. Nearly 8 years have elapsed since the establishment of this committee, and during this period the ability and skill of the group leaders and members in managing group activities and their awareness of problems and solutions have been greatly improved, thereby contributing much to the improvement of quality, attainment of production targets, reduction in the production costs, and improvement of safety

This report describes the ’ Jishu Kanri ’ activities being carried out by the industry as a whole.     

Window functions obtained by convolution integrals of rectangular windows

The rectangular, triangular, and Parzen windows, which have been defined independently of each other, are obtained by repeating convolution integrals of the rectangular window with itself. They are extended to make a series of window functions. This series has the advantage that the sidelobe fall-off is variable though it has the disadvantage that the mainlobe band-width for the same highest sidelobe level is 1–1·3 times those of the gaussian, Kaiser, Dolph–Chebyshev or Blackman–Harris windows. Moreover, this series has a desirable mainlobe bandwidth of 0·85–1 times that of cos^x x windows for the same highest sidelobe level and sidelobe fall-off. Thus, this series is useful in designing window functions whose mainlobe bandwidth is in between that of the gaussian or Kaiser windows and that of cos^x x windows and whose sidelobe fall-off is as good as that of the cos^x x windows.