梳毛机除草装置工艺参数的优化

本文利用系统工程原理和回归正交实验方法,在小型去草梳毛机上模拟真实加工条件,对除草装置的主要工艺参数:除草刀与莫雷尔辊(或开毛辊)之间隔距,除草刀表面线速度.除草刀罩壳前、后开口高度进行了优化。得出,①除草刀与开毛辊或莫雷尔辊之间的隔距越小,除草率和落毛率越高。②除草刀罩壳的前开口高度越大,落毛率越高。但当取小隔距时,前开口高度越大,除草率越高。③除草率与线速度比V_1/V_2成正比(指除草刀与开毛辊或莫雷尔辊之间线速度比);而落毛率则与其为负指数关系。当线速度比大于6时除草率较高同时落毛率较小.④加大除草刀罩壳的后开口高度,可提高除草率并减少落毛率。实验结果与作者提出的除草刀作用数学模型分析一致。此外,还优选出上述几个除草作用区的工艺参数调节范围。使除草效率分别提高32～52％.     

有限深抛物量子阱中的类氢杂质态

运用三参数变分法,研究了在垂直于生长方向的磁场作用下抛物量子阱中类氢杂质态的束缚能和1s→2p-态跃迁能.结果表明,束缚能和跃迁能随阱宽变化有一极大值;束缚能随磁场单调增加,而跃迁能随磁场的变化出现了极小值.     

Effect of sintering temperature on the preparation of Cu–Ti3SiC2 metal matrix composite

Ti3SiC2 has the potential to replace graphite as reinforcing particles in Cu matrix composites for applications in brush,electrical contacts and electrode materials.In this paper the fabrication of Cu-Ti3SiC2 metal matrix composites prepared by warm compaction powder metallurgy forming and spark plasma sintering(SPS) was studied.The stability of Ti3SiC2 at different sintering temperatures was also studied.The present experimental results indicate that the reinforcing particles in Cu-Ti3SiC2 composites are not stable at and above 800℃.The decomposition of Ti3SiC2 will lead to the formation of TiC and/or other carbides and TiSi2.If purity is the major concern,the processing and servicing temperatures of the Cu-Ti3SiC2 composite should be limited to 750℃ or lower.The composites prepared by warm compaction forming and SPS sintering at 750℃ have lower density when compared with the composites prepared by SPS sintering at 950℃,but their electrical resistivity values are very close to each other and even lower.     

高通量氢等离子体对CX-2002U碳复合材料的化学侵蚀研究

针对HL-2M偏滤器等离子体对碳材料的侵蚀问题,通过使用直线等离子体装置(SCU-PSI)模拟偏滤器的工况以探究高通量氢等离子体对CX-2002U碳纤维复合材料的侵蚀行为,从而为此材料能否用于HL-2M装置的偏滤器提供依据. 在通量恒定(1.48×1023 m-2s-1)的条件下,通过研究不同辐照时间下氢等离子体对样品的化学侵蚀发现,氢等离子体对样品的侵蚀是一个随时间周期变化的过程. 此外,通过在氢气中混入杂质气体探究了杂质对氢等离子体侵蚀样品的影响并发现,氢等离子体中的杂质通过侵蚀沉积在样品表面的碳颗粒以增强其对样品的侵蚀.     

The effect of Al and Cr elements on the oxidation resistance of MoSi_2 via first-principles calculation

The properties of structure, energy and oxidation resistance of interstitial and substitutable MoSi_2 systems have been investigated using the density functional theory. The calculated lattice constants for pristine MoSi_2 confirm the early experimental results. In the interstitial MoSi_2, the impurity energy of O atom was computed for the stable interstitial site in the systems. The results reveal that the O atom prefers to occupy the Oct2 site with the lowest impurity energy. In the substitution MoSi_2, the Si sites tend to be substituted with Al and Cr atoms,whereas, Mo sites do not behave like the Si sites. The co-substitution of Al/Cr atoms and the direction of the O diffusion in MoSi_2 have been analyzed as well. The results from electronic structural analysis indicate that the SiO bond is the main factor to inhibit the diffusion of O, and the alloying elements of Al and Cr contribute to the oxidation resistance of MoSi_2.     

量子棒中极化子基态能量的杂质效应

通过坐标变换把量子棒的哈密顿量由椭球边界变为球形边界.采用线性组合算符方法,研究了量子棒中弱耦合杂质极化子的基态能量与椭球纵横比、量子棒的横向和纵向有效受限长度、库仑束缚势和电子-声子耦合强度的关系.结果表明：基态能量随有效受限长度的减少而迅速增大.表现出量子棒珍奇的量子尺寸限制效应.基态能量随库仑束缚势、纵横比和耦合强度的增加而减少.     

混晶GaAs_(1-x)P_x∶N中N_X带的发光瞬态过程研究

采用皮秒量级的超快速光谱技术，分析了混晶ＧａＡｓ１－ｘＰｘ∶Ｎ材料发光瞬态过程．结果证实了材料随组份变化，从间接带到直接带（ｘｃ＝０．４５Ｋ，７７Ｋ）转变的带增强效应．对ＮＸ发光带不同能量位置的发光衰退测量还表明ＮＸ带同时存在着快速的带内隧穿转移和较慢的发光衰退过程     

杂质对切削液的危害及对策

从理论上分析了杂质对切削液的危害,提出了在各种切削加工中应使用精细过滤切削液的观点,并讨论了滤器的选择和切削液的检测问题。     

双汞探针C—V法测试硅材料杂质浓度分布

鉴于单汞探针C-V法测试半导体材料杂质浓度分布还有不方便之处及不能准确测试n/p;p/n等异型多层结构外延片电阻率分布的弊病,本文提出了双汞探针C-V法。文章中阐述了这种方法的测试原理和测试可行性分析。对各种硅材料样片大量测试结果表明:这种方法即方便又准确,测试结果的重复性相当好。