Trace Equivalence in SU(2, 1)

In this paper it is shown that one can choose an arbitrarily large number of inconjugate elements of the group Z/2Z*Z/2Z*Z/2Z which have the property that, under all representations of the group in SU(2,1) as a discrete complex hyperbolic ideal triangle group, the elements are hyperbolic and correspond to closed geodesics of equal length on the associated complex hyperbolic surface. This is an analogue of the geometric fact that the multiplicity of the length spectrum of a Riemann surface is never bounded or the equivalent algebraic phenomenon that an arbitrarily large number of conjugacy classes in a free group can have the same trace under all representations in SL(2,R ).     

合成丙交酯中微量水分分析

合成丙交酯中微量水分分析徐溢，柳胜春（重庆大学化工学院分析教研室６３００４４）关键词丙交酯，微量水，定量分析丙交酯是人工合成骨材料聚乳酸的合成中间体，其性能决定着合成产品的品质，要获得高质量的合成材料，对中间体的分析和监测十分重要。一般要求丙交酯中间...     

An invariant trace formula for the universal covering group of SL(2,ℝ)

Automorphic forms of arbitrary real weight can be considered as functions on the universal covering group of SL(2, ). In this situation, we prove an invariant form of the Selberg trace formula for Hecke operators. For this purpose, the Fourier transforms of weightet orbital integrals, obtained by J. Arthur, R. Herb and P. Sally, jr., are explicitly calculated. Our formula does not follow from Arthur's invariant trace formula, since the group has infinite centre, and vector-valued automorphic forms with respect to non-congruence lattices are considered.     

Convergence of Krylov methods for sums of two operators

We discuss the convergence of Krylov subspace methods for equationsx =Tx +f whereT is a sum of two operators,T =B +K, whereB is bounded andK is nuclear. Bounds are given for inf Q _k (B+K) and for inf p _k (B+K), where the infimum is over all polynomials of degreek, such thatQ _k is monic andp _k is normalized:p _k (1) = 1.     

双硫腙萃取富集-石墨炉原子吸收光谱法测定水体中痕量钴

介绍利用双硫腙(D2)作为螯合萃取剂,对水体中痕量钴进行萃取富集,采用基体改进技术由自动进样器注入石墨炉测定水中痕量钴的方法.本法操作简便、价廉、灵敏度和回收率高,加标回收率为97.4%～104.4%,RSD<3.47%.     

纳米结构陶瓷(n-WC/12Co)涂层材料精密磨削的试验研究

对纳米结构陶瓷(n—WC／12Co)涂层材料在金刚石砂轮精密磨削过程中的磨削力进行了较详细的试验研究，对常规结构陶瓷(c—WC／12Co)和n—WC／12Co涂层材料的磨削力作了对比磨削试验。分析了磨削工艺参数如砂轮磨削深度、工件进给速度、金刚石砂轮粘结剂类型和磨粒尺寸以及被磨试件材料特性等对磨削力的影响。结合被磨试件表面的扫描电镜(SEM)的观察，分析了n—WC／12Co涂层材料磨削的材料去除机理。     

二甲磺酸阿米三嗪-β-环糊精包合物的鉴定

通过共沉淀法制备了二甲磺酸阿米三嗪 β 环糊精包合物,使用红外光谱、差示扫描量热法加以鉴定。证实了二甲磺酸阿米三嗪 β 环糊精包合物的生成,形成包合物后,二甲磺酸阿米三嗪得到了稳定。     

激光图案自动变幻仪的成像分析

介绍了激光图案自动变幻仪，对旋转平面镜的反射进行了理论分析，并以此理论为基础对仪器产生的扫描轨迹成像进行了数学近似处理，并编制了图案的计算机仿真程序。     

恭城沙田柚果实品质与土壤环境化学的研究

在恭城县城选择三不同情况的沙田柚环境（挂果好，当年产３００多个，挂果一般，当年产５０个，从不挂果，树龄已有８年，结果无望）采样，分析土壤，果实，树枝叶的常量元素和微量元素，结果表明，恭城沙田柚全糖含量平均值达１０％以上，可溶性固形物含量达１７％，柠檬酸０．３１％，糖酸比和固酸比多在３０以上。品质优的沙田柚生长的土壤Ｋ２Ｏ，Ｐ２Ｏ５含量分别为１．８００３％～２．２１２５％和０．１５２４％～０．１８１     

鸡不同组织中铜、锌、铁、锰含量及相关性分析

用原子吸收分光光度法测定了迪卡公鸡１０种组织铜、锌、铁、锰的含量，并对其进行了多重比较分析。结果表明，公鸡不同组织４种微量元素的含量差别很大（Ｐ＜０．０５或Ｐ＜０．０１）。大多数组织４种微量元素的含量大小为：铁＞锌＞铜＞锰；同一类组织的不同部位，其微量元素的含量也有明显差异（Ｐ＜０．０５）。在鸡体内，微量元素在各组织间均存在一定的相关关系