Densification of plasma deposited silicon nitride films by hydrogen dilution

The effects of hydrogen dilution on the bonding characteristics, composition, and properties of SiN films deposited from a SiH₄/NH₃ mixture by r.f. plasma enhanced chemical vapor deposition were studied. The addition of relatively small amounts of hydrogen increased the Si/N ratio resulting in a corresponding increase in the Si---H/N---H bonding ratio. At higher hydrogen dilutions, the Si/N ratio decreased towards stoichiometric with significant changes in the hydrogen bonding characteristics. Changes in the physical properties are discussed in terms of the measured changes in bonding structure. Changes normally associated with changes in bulk film density were found to be well correlated to the Si---N bond density. The effects of substrate temperature and NH₃/SiH₄ ratio on films deposited under conditions of high hydrogen dilution were similar to those widely reported in the literature for plasma-enhanced chemical vapor deposition films deposited without hydrogen. Films deposited by remote plasma using hydrogen as the excitation exhibited high Si---N bond densities and low hydrogen. Experiments are planned to clarify the mechanism responsible for the observed changes in film properties.     

CaF_2-CaO-MgO-Al_2O_3-SiO_2电渣渣系高温力学性能的研究

本文针对结晶器与铸锭作相对移动的电渣重熔过程中对渣系的高温强度及塑性的要求,对10种CaF_2-CaO-MgO-Al_2O_3-SiO_2渣组成进行了渣的高温强度及塑性的测定,建立了渣组成—渣的岩相结构—渣高温强度及塑性间的对应关系,并选择出较合适的成分范围为CaF_2 35～60％,CaO 10～25％,Al_2O_3 10～20％,SiO_25～15％,MgO≈5％。对其中一个成分的渣进行了电渣热穿孔熔铸中空锭生产实验,并取得了良好的表面质量。     

铝液夹杂物检测DMIRT－Ⅲ法的试验研究

提出了一种新的铝液夹杂物快速检测方法。导出了该法的检测原理方程。分析并试验研究了影响检测重复性和分辨率的因素。试验选择了较好的检测参数，并获得了较好的检测结果。     

极尖断面为折线的四极透镜磁性能研究

对传统双曲线极尖的四极透镜进行了磁性能分析。在此基础上，提出了极尖断面为折线的四极透镜结构。磁场的数值分析以及测量结果表明：该结构产生的场梯度均匀，且具有磁场集中、磁场梯度高、便于加工和安装的对称性控制等优点。该结构的四极透镜已用于ＣＹＣＩＡＥ－３０回旋加速器和ＨＩ－１３串列加速器束流输运线之中     

TiNi shape memory alloys prepared by normal sintering

This paper covers the use of conventional press and sinter of titanium and nickel equiatomic blends, involving transient liquid phases. A notable development has been the fabrication of homogeneous compacts from the elemental powders. Results indicate that employment of a double-stage sintering cycle is effective to sustain the geometrical integrity of the sintered sample. The TiNi alloy prepared in this manner exhibits a recovery strain of 4.6% by generating a restoring stress of 230 MPa, with a martensitic transformation point M_s of 34 °C.     

单元系T—p相图的数学结构

作者以化学元素的稳定单质为基准,推演出了任意物质M_i(相态Ω)的热力学生成活度{相态Ω)的函数形式:?D_Ω数值的大小体现着相态Ω的热力学相对稳定性.根据集合论原理沿D(稳定性)座标取极大值的方法把物理性质互不连续的各个异相态连结在一起,建立了单元系在T-p面上的优势分布方程(PSDE):■作者以H_2O为实例,计算了T-p相图,与实验相图基本一致.     

The Effect of Initial Inventories in a Two-Echelon System

A model in which jointly optimal stocks of material and finished products are to be chosen is reexamined. While it costs less to hold material, a certain percentage of the random demand not immediately satisfied by previously finished products is lost. We pay particular attention to the dependence of the optimal stocks on the initial ones, which assumes an interesting form. For example, if the stock of finished products is high but the combined stock is low, die quantity of material ordered depends on the stock of finished products.