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41.
42.
根据作者多年工作经验,详细介绍了复混肥料中钾合量的到定,且与标准GB/T8574—1988进行了逐一比较。 相似文献
43.
Resilient optical networks are predominately designed to protect against single failures of fiber links. But in larger networks, operators also see dual failures. As the capacity was planned for single failures, disconnections can occur by dual failures even if enough topological connectivity is provided. In our approach the design of the network minimizes the average loss caused by dual failures, while single failures are still fully survived. High dual failure restorability is the primary aim, capacity is optimized in a second step. For WDM networks with full wavelength conversion, we formulate mixed integer linear programming models for dedicated path protection, shared (backup) path protection, and path rerouting with and without stub-release. For larger problem instances in path rerouting, we propose two heuristics. Computational results indicate that the connectivity is of much more importance for high restorability values than the overall protection capacity. Shared protection has similar restorability levels as dedicated protection while the capacity is comparable to rerouting. Rerouting surpasses the protection mechanisms in restorability and comes close to 100% dual failure survivability. Compared to single failure planning, both shared path protection and rerouting need significantly more capacity in dual failure planning. 相似文献
44.
低光照和抗晕CCD的设计和制作 总被引:2,自引:1,他引:1
针对帧转移可见光CCD低光照响应、抗电晕能力和动态范围,较详细讨论了CCD光响应灵敏度、动态范围和抗电晕的设计与计算。设计的具有抗晕功能CCD,采用2μm工艺制作,达到了设计技术指标要求,满足了工程应用需求。 相似文献
45.
46.
Shizuo Arichi Noriyuki Sakamoto Shozo Himuro Mayumi Miki Masafumi Yoshida 《Polymer》1985,26(8):1175-1180
In order to obtain the additional data concerning the unperturbed dimension of poly-4-substituted styrene, light scattering measurements are performed on the twenty-two fractions with molecular weight of (0.91–352)·104 of poly(4-acetoxystyrene) in dioxan at 25°C, from which the molecular weight obtained was found easily to be evaluated with the gel permeation chromatography using THF. Phase separation experiments for this polymer indicate that the theta state is attained in isopropyl acetate at 19.7°C and butyl acetate at 26.8°C. By making viscosity measurements at that state, the value of KΘ is directly evaluated as 5.4·10?4 dl g?1. The limiting viscosity number is also obtained in good solvents, THF and dioxan, at 25°C and constants of the Mark-Houwink-Sakurada equation in each solvent are determined. Further, approximately the same KΘ as above is obtained from these data with the Stockmayer-Fixman plot. The calculated value of steric factor, 2.37, on this polymer may be plausible, compared with those of polyvinylaromatic derivatives. 相似文献
47.
Critical-point drying and freeze drying were compared both quantitatively and qualitatively as preparative procedures for scanning electron microscopy. Isolated hepatocytes were used as model cells. Nomarski differential interference contrast microscopy was used for light microscopic measurements of the hepatocytes in the unfixed, the glutaraldehyde fixed, the glutaraldehyde + OsO4 fixed, the critical-point dried and the freeze dried states. Critical-point dried hepatocytes were found to shrink to 38% of glutaraldehyde + OsO4 fixed volume, whereas optimal freeze dried hepatocytes (frozen in water saturated with chloroform and freeze dried at 183 K for 84 h) were found to shrink to 51% of glutaraldehyde + OsO4 fixed volume. Transmission and scanning electron micrographs of the critical-point dried cells showed well-preserved ultrastructure and surface structure. Micrographs of the freeze dried cells showed ultrastructure destroyed by internal ice crystals and surface structure destroyed by external ice crystals. Double-fixed isolated hepatocytes were shown to swell during storage in buffer and to shrink during storage after critical-point drying. For low magnification scanning electron microscopy (up to about 3000 times) both critical-point drying and freeze drying can be used. However, for high magnification scanning electron microscopy, critical-point drying is superior to freeze drying. 相似文献
48.
天然多糖类/蛋白质复合材料的研究进展 总被引:5,自引:0,他引:5
在参考了 31篇文献的基础上 ,详述了天然多糖类与蛋白质复合材料的研究进展 相似文献
49.
二维多孔数控钻床加工路径的生成及优化 总被引:7,自引:0,他引:7
印刷电路板 PCB的加工是二维多孔数控钻的典型。实践表明加工同一零件不同的走刀路径其长度相差极大。为提高生产率 ,应使刀具的走刀路径尽量短 ,这其实是大型的 TSP问题。本文提出了几种路径的生成方法 ,分析了各自的适用场合。并用实例验证所提出的路径生成方法可极大地提高实际钻孔的加工效率。 相似文献
50.
复合式水力旋流器油水分离实验研究 总被引:5,自引:0,他引:5
复合式水力旋流器将动态与静态旋流分离技术有机地结合在一起 ,具有动态与静态水力旋流器的双重优点。这种旋流器由动力组件 (包括电动机、空心驱动轴、旋转栅及溢流嘴等 )、静态旋流单体、入口腔、底流腔及溢流腔等部分组成。对额定处理量为 8m3/h样机的分离特性测试表明 ,当电动机驱动轴转速低于 30 0 0r/min时 ,入口压力为 0 10~ 0 35MPa ,底流压差为0 0 5~ 0 2 0MPa ,处理量为 3~ 10m3/h ,选用单螺杆泵增压和离心泵增压两种方式 ,分离效率分别为 97%和 84 % ,均取得满意的分离效果。 相似文献