一类非交换群环的零因子图的性质

讨论了非交换群环Zn Dm的零因子图的性质，对非交换群环Zn Dm的零因子图的围长、直径和平面性给出了刻画，其中Zn为模n剩余类环， Dm为2m阶二面体群。     

微/纳米氧化锌的制备与粒度表征

微/纳米氧化锌是一类重要的新型无机材料。本文主要采用溶胶-凝胶法,用乙酸锌、草酸和无水乙醇制备微/纳米氧化锌,分别从反应物浓度、表面活性剂种类、表面活性剂添加量三个方面进行探究。实验结果表明,当草酸乙醇溶液和乙酸锌溶液浓度分别为0.6 mol/L、0.9 mol/L时,pH为1,按质量比1:1复配的比例添加十二烷基硫酸钠和聚乙烯吡咯烷酮,煅烧,测得所制备的氧化锌纯度高,晶型良好,粒径分布均匀。     

图的最大亏格与直径

设G是直径为4的简单图,若G不含3阶完全子图K3,则G的Betti亏数ξ(G)≤2,即G的最大亏格γM(G)≥1/2β(G)-1,并且不等式的下界是可达的。这种结合图的直径等条件的证明方法改进了相关结果。     

基于光衍射法的细丝线度测量

用光衍射法对头发丝直径进行测量,且对其作误差分析.对光衍射法做了扩展实验,测量标准丝的微小位移.实验数据表明,用光衍射法测量细丝的线度和微小位移是可行的.     

Modified model of bubble formation in non-Newtonian fluids

Based on the comprehensive forces balance model,a modified model of the formation of a single bubble in non-Newtonian fluid under constant flowrate was developed by taking account of the effect of the ingoing gas through orifice as well as its variation OH the radial expansion of bubble.The modified model involves the radial expansion equation of bubble surface and the forces balance equation in vertical direction of the bubble respectively.The shape variation of bubbles formed in polyacrylamide(PAM)aqueous solutions under various conditions was predicted numerically.The practical formation of bubbles was real-time visualized and recorded by a CCD camera and a computer by means of a special laser image measurement system.Results show that the predicted shapes of the bubbles by the present model agree well with experimental observation.     

锥形壳体按中径公式设计的限定条件

按GB150《钢制压力容器》的规定,圆筒形壳体、球形壳体和锥形壳体的壁厚都可按中径公式进行计算,且对圆筒形壳体和球形壳体给出了公式应用的限定条件,但对锥形壳体却没有给出限定条件.通过对圆筒形壳体和锥形壳体薄膜应力及壁厚计算公式的分析和比较,提出了锥形壳体按中径公式计算壁厚时的限定条件.     

Coalescence Behaviors of Drop Swarms on Liquid-Liquid Interface

The trajectory model of dispersed phase drops and distribution model of drop diameters were derived.By numerical simulation,the analytical results indicate that a large number of dispersed phase drops accumulate on the upper plate in different directions and form a hydrodynamic area with the stream-wise location in the range of 0—0.4m,where the flow of trickling film obtains kinetic drive from flowing field.The flowing field of trickling film exhibits an unstable state if the stream-wise location is less than 0.02m,and a stable state otherwise.Moreover,different velocity vectors of drops in the x-y plane result in different interactions between the trickling film and drops.For the non-uniform distribution of drop diameters,there is a stronger interaction between the trickling film and drop if the stream-wise location is less than 0.02m,because the amplitudes of velocity vectors are higher than those in the range of 0.02—1.0m.The result reveals a complexity and diversity of stratified two-phase flowing field.On the other hand,both the basic flowing field and distributions of drop diameters have a great influence on the distributions of comparable kinetic energy of drops.The complicated motions of larger drops are helpful to coalescence because they will consume much more kinetic energy on the trickling film than those of smaller drops.The change of comparable kinetic energy of smaller drops is continuous and steady.The smaller drops are easily entrained by the liquid-liquid flowing field.     

k-超图的直径

研究超图的直径,首先给出直径与拉普拉斯张量最大特征值的关系;其次给出直径与秩k的关系;最后给出直径为1的极小k-超图的边数的下界,并证明对任意的k,下界都是紧的.     

大芯径直锥形塑料光纤的制作

理论分析了子午光线通过直锥形塑料光纤的光线传输原理,模拟计算了直锥形光纤的锥角α、光纤中心轴线夹角θ(m)与反射次数m三者的变化关系.通过重力垂直拉锥实验制作了大芯径直锥形塑料光纤,并得出相关的实验结论.     

浅谈带节流圈的小径管焊缝超声波探伤方法

本文是针对某电厂1#机组低温再热器联箱短接管焊缝加节流圈的焊缝,因其特殊结构,不能进行射线探伤检验,而采用超声波方法进行检验,通过实践证明这种方法是有效可行的。