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Using the notion of biconnected sum we define the biconnected sum (T1, M1)§(T2,M2) of two involutions (T1M1) and (T2,M2) which is an involution on the biconnected sum M1,§M2. A connected involution is said to be reducible if it can be expressed as a biconnected sum of two connected involutions.Theorem Each connected involution (T, M) can be decomposed into a bi-connected sum of connected irreducible involutions (T, M)=(T1, M1)§…§(Tq,Mq),and (?) where the coefficients of Hn_1(M) are in Z/2 Z if M is unoriented, in Z if is oriented . 相似文献
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将文献[1]给出的由一维连续型随机变量的概率密度函数构造二维连续型随机变量的概率密度函数的方法,推广为由一维连续型随机变量的概率密度函数构造三维连续型随机变量的概率密度函数的情况,并作出了证明和举例说明.说明利用本文的方法构造多维概率密度函数,其方法简单易行. 相似文献
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Preparation of Cu(In,Ga)Se2 Thin Film Solar Cells by Selenization of Metallic Precursors in an Ar Atmosphere 总被引:1,自引:0,他引:1 下载免费PDF全文
Cu(In, Ga)Se2 thin films are deposited on Mo-coated glass substrates by Se vapour selenization of sputtered metallic precursors in the atmosphere of Ar gas flow under a pressure of about 10 Pa. The in situ heat treatment of as-grown precursor leads to the formation of a better alloy. During selenization, the growth of CuInSe2 phase preferably proceeds through Se-poor phases as CuSe and InSe at relatively low substrate temperature of 250℃, due to the absence of In2Se3 at intermediate stage at low reactor pressure. Subsequently, the Cu(In,Ga)Se2 phase is produced by the reactive diffusion of CuInSe2 with a Se-poor GaSe phase at high temperature of up to 560℃. The final film exhibits smooth surface and large grain size. The absorber is used to fabricate a glass/Mo/Cu(In, Ga)Se2/CdS/ZnO cell with the total-area efficiency of about 7%. The low open-circuit voltage value of the cell fabricated should result from the nonuniform distribution of In and Ga in the absorber, due to the diffusion-controlled reaction during the phase formation. The films, as well as devices, are characterized. 相似文献
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研究了邻苯二酚与乙醇气固相单醚化反应用固体酸催化剂表面上的积炭行为,并用TG-DTA,BET,GC-MS,FT-IR和元素分析等手段对积炭物种进行了表征.结果表明,催化剂上有两种类型的积炭,一类属可溶性积炭,主要由二苯醚及其衍生物组成,可在低温燃烧除去;另一类属不可溶性积炭,主要为缺氢的芳烃类聚合物或类石墨碳,需在高温下才能烧除.积炭主要发生在4~8nm范围的中孔内,导致反应后的催化剂大孔范围的孔分布所占的分数增大.随着反应的进行,总积炭量逐渐增多. 相似文献
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The mononuclear macrocyclic polyamine metal complexes 5a-5e have been shown to form stable 1 : 1 complexes with bases and nucleosides. Their binding constants (K) were determined by UV-visible spectrometric titration. The results show that recognition ability of the complexes 5a--5e for uracil, U (Uridine), dT (Thymidine) is higher than that for the other bases or nucleosides (such as Cytidine, Guanosine, Adenosine). The metal ion also plays an important role for the recognition ability of complexes. 相似文献