WDM光网络中光层组播技术的研究

本文分析了光层组播原理。在物理层实现组播 ,使该技术在整个互联网实施实时交互音像通信和有效抑止“电子瓶颈”效应有着重大作用。文中对两种不同结构具有光层组播的OXC进行了分析比较。并且对WDM光网络中的无阻塞组播通信波长满足条件进行了分析探讨。     

Granular structure and allomorph position in C-type Chinese yam starch granule revealed by SEM,C CP/MAS NMR and XRD

The crystalline microstructure and polymorphism of C-type starch from Chinese yam were evaluated by scanning electron microscope (SEM), ¹³C cross-polarization magic-angle spinning NMR (¹³C CP/MAS NMR) and powder X-ray diffraction (XRD) technique and acid hydrolysis method. Morphological changes during acid hydrolysis showed that the amorphous or the less crystalline areas were essentially located at the center part of C-type starch granules whereas the semi-crystalline and amorphous growth rings were found mainly in the outer part of the granules. ¹³C CP/MAS NMR and XRD results revealed that B-type allomorph was hydrolyzed more rapidly than A-type one. The amorphous or less crystalline areas were predominantly composed of B-allomorph whereas the outer semi-crystalline and amorphous growth rings were mostly composed of A-type allomorph. The A- and B-type allomorph coexisted in the individual C-type starch granule. B-type allomorph basically existed at the center part of the granules which was surrounded by the A-type allomorph in the peripheral part of granules.     

Sulfur as a Bridge: Synthesis of Medium Rings via a Bicyclic Sulfonium Ion

A facile and efficient synthesis of medium rings via a bicyclic sulfonium ion was developed. Spectroscopic evidence for the formation of an intermediate sulfonium moiety is provided. The sulfur atom served as a “bridge” to access the medium ring system and could be removed after use via a Ramberg–Bäcklund process. As a result of the readily available starting materials, simple operation, and mild conditions, these reactions should be an appealing strategy in organic synthesis.     

内沟槽环件辗压成形工艺模拟研究

针对异形截面环件壁薄、断面形状较复杂的特点,可用辗压工艺成形内沟槽环件。利用有限元数值模拟技术,研究了辗压过程中金属变形流动特点、成形规律等,并分析了轧制孔型、摩擦因数、进给速度对成形效果的影响。结果表明:采用辗压成形内沟槽环件,工艺过程简单;轧制孔型、摩擦因数对成形效果影响较大。     

内燃机活塞环调质稀土离子渗氮处理的摩擦磨损性能

通过改善活塞环的磨损、腐蚀抗力来提高其使用寿命.利用相应的仪器和设备,对经调质处理后的活塞环进行了表面稀土离子渗氮处理和金相观察,并将调质后稀土离子渗氮处理的活塞环与表面未经任何处理的活塞环制出3组试样,对不同的载荷及不同时间内的磨损情况进行了对比试验研究.结果表明,采用调质后稀土离子渗氮活塞环的抗磨损性能和腐蚀抗力优于原始环.通过装机试验,经调质后稀土离子渗氮的活塞环耐磨性能明显高于其他措施处理的活塞环.     

渗流作用下圆形巷道围岩弹塑性分析

在假设岩体在无限小的区域内材料属性相同,将岩体划分为若干个塑性区域环的情况下,应用统一强度理论,结合岩石应变软化力学模型与围岩峰后强度和变形演变规律,推导了渗流作用下圆形巷道围岩破裂分区的计算公式,分析了渗流作用下巷道围岩的弹性区、塑性软化区和破裂区的力学性态。结合具体算例,对比分析了渗流作用下和无渗流作用下巷道塑性区范围影响因素,得出支护反力、巷道半径以及采深对渗流作用下的巷道塑性区域影响尤为明显。研究表明,考虑渗流作用使得分析结果更加接近于实际,能显示出巷道围岩变化破坏情况,为地下工程的优化支护设计及安全性评价提供理论依据。     

双环永磁轴承径向偏移承载能力的研究

在分析永磁轴承基本结构的基础上,提出了双环永磁轴承的结构,并进一步分析了该轴承的工作原理和径向偏移承载能力,推导了径向磁吸力、轴承间隙、剩磁之间的关系,经仿真其结果表明:大部分磁力线形成闭合回路,最大限度地减少了磁力线的对外散发,保证了永磁环性能的稳定,延长了永磁环的使用寿命;径向磁吸力随轴承间隙的增大逐渐减小,随表面剩磁的增加而增大;轴承的径向刚度等于长度为半周长的线性模型的刚度。     

牛顿环实验装置螺钉压力大小对曲率半径测量结果的探讨

研究牛顿环实验装置螺钉压力大小对平凸透镜曲率半径测量结果的影响。实验结果表明:在牛顿环的实验过程中,应把螺丝调整到合适的程度,使中心暗环直径在1~2 mm为宜。螺丝太松则导致平凸透镜和平板玻璃的触点不稳定,干涉条纹易受环境影响,使偶然误差增大。螺丝太紧则导致平凸透镜和平板玻璃之间弹力加大,使平凸透镜形变增大,导致中心斑增大,使测量系统误差增大。     

牛顿环现象及其应用

阐述了牛顿环干涉原理，解释了牛顿环实验图样和附加光程差对牛顿环图样的影响，并指出应用牛顿环现象可判断透镜表面凸凹、精确检验光学元件表面质量、测量透镜表面曲率半径和液体折射率。     

新型钢领钢丝圈系统

综述了几种新型的钢领钢丝圈系统，提出了将纳米和磁悬浮等高新技术应用于纺织器材的方法，并指出开发新型钢领结构是钢领钢丝圈系统的发展趋势。