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71.
P. Maroni 《Journal of Difference Equations and Applications》2013,19(9):1519-1530
In the present work, we deal with the quadratic decomposition of symmetric semi-classical polynomial sequences of even class. An example from class 2 is settled. We give an integral representation of the considered symmetric form. 相似文献
72.
J. Herzberger 《Numerical Functional Analysis & Optimization》2013,34(5-6):521-533
A family of higher-order iterative methods for inverting a linear bounded operator in a Banach space is presented. This family depending on two integer parameters can be considered as hyperpower methods of [1]. A convergence Theorem is proved and an optimal class with respect to the efficiency index is determined . Several error bounds are derived and compared with those in the literature. 相似文献
73.
74.
75.
Jinhua Wang Dr. Barbara Wicher Dr. Victor Maurizot Prof. Ivan Huc 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(3):1031-1038
Quinoline based aromatic amide foldamers are known to adopt stable folded conformations. We have developed a synthetic approach to produce similar oligomers where all amide bonds, or part of them, have been replaced by an isosteric vinylene group. The results of solution and solid state structural studies show that oligomers exclusively containing vinylene linkages are not well folded, and adopt predominantly flat conformations. In contrast, a vinylene segment flanked by helical oligoamides also folds in a helix, albeit with a slightly lower curvature. The presence of vinylene functions also result in an extension of π-conjugation across the oligomer that may change charge transport properties. Altogether, these results pave the way to foldamers in which both structural control and specific electronic properties may be engineered. 相似文献
76.
Interpolating minimal energy C1‐Surfaces on Powell–Sabin Triangulations: Application to the resolution of elliptic problems
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M. A. Fortes P. González M. J. Ibáñez M. Pasadas 《Numerical Methods for Partial Differential Equations》2015,31(3):798-821
In this article, we present a method to obtain a C1‐surface, defined on a bounded polygonal domain Ω, which interpolates a specific dataset and minimizes a certain “energy functional.” The minimization space chosen is the one associated to the Powell–Sabin finite element, whose elements are C1‐quadratic splines. We develop a general theoretical framework for that, and we consider two main applications of the theory. For both of them, we give convergence results, and we present some numerical and graphical examples. © 2014 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq 31: 798–821, 2015 相似文献
77.
目的 探讨右半结肠癌行完全结肠系膜切除术(CME)清扫肠系膜根部淋巴结的临床疗效。方法 以2010年12月
至2012 年12 月行CME 的57 例右半结肠癌患者作为观察组,同期接受传统结肠癌根治术的99 例右半结肠癌患者作为对照组,对两组患者的淋巴结清扫数量、平均出血量、手术时间、住院时间、术后排气、排便时间、手术并发症、2年局部复发率及生存率等情况进行比较,初步评价CME 清扫肠系膜根部淋巴结的临床效果。结果 CME 组与对照组总淋巴结清扫数量分别为(22.6±2.8)、(14.6±2.7)枚,CME 组淋巴结清扫数量明显多于对照组(P<0.05);CME 组平均出血量为(167.4±20.8)ml,对照组为(205.4±19.3)ml,CME 组出血量少于对照组(P<0.05);两组的手术时间、住院时间、术后排气、排便时间比较差异均无统计学意义(均P>0.05);CME 组手术并发症发生率与对照组比较差异无统计学意义(P >0.05);Ⅲ期患者CME 组2 年局部复发率38.2%、生存率88.2%,对照组分别为64.8%和68.5%,两组差异有统计学意义(均P<0.05)。结论 右半结肠癌患者采用CME 清扫肠系膜根部
淋巴结是安全和有效的。 相似文献
78.
This paper presents the theoretical analysis of adaptive multiuser RAKE receiver scheme in frequency selective fading channel for direct-sequence code division multiple access (DS-CDMA) system. Least mean square (LMS) algorithm is used to estimate the channel coefficients. Chaotic sequences are used as spreading sequence and corresponding bit error rate (BER) in closed form is derived for imperfect channel estimation conditions. Performances of chaotic sequences are compared with pseudorandom noise (PN) sequences. Under perfect synchronization assumption, various simulation results are shown to investigate the performance of the proposed system. 相似文献
79.
一种四次有理插值样条及其逼近性质 总被引:3,自引:0,他引:3
1引言有理样条函数是多项式样条函数的一种自然推广,但由于有理样条空间的复杂性,所以有关它的研究成果不象多项式样条那样完美,许多问题还值得进一步的研究.近几十年来,有理插值样条,特别是有理三次有理插值样条,由于它们在曲线曲面设计中的应用,已有许多学者进行了深入研究,取得了一系列的成果(见[1]-[7]).但四次有理插值样条由于其构造所花费的计算量太大以及在使用上很不方便而让人们忽视了其重要的应用价值,因此很少有人研究他们.实际上,在某些情况下四次有理插值样条有其独特的应用效果,如文[8]建立的一种具有局部插值性质的分母为二次的四次有理样条,即一个剖分 相似文献
80.
Pure enantiomers of chiral (atropisomeric) polychlorinated biphenyls (PCBs) obtained by high-performance liquid chromatography were used to establish the gas chromatographic elution sequences of the (+)- and (−)-enantiomers of six PCB atropisomers on Chirasil-Dex. The elution order was found to be (−/+) for PCBs 84, 132, 136, and 176 and (+/−) for PCBs 135 and 174. The retention characteristics of all 19 tri- and tetra-ortho atropisomeric PCBs were also investigated. Nine of the atropisomers could be separated using this chiral selector. PCBs 95, 132, and 149 were completely resovled and PCBs 84, 91, 135, 136, 174, and 176 were partially separated (R = 0.7–0.9). All of the separated congeners are 2,3,6-substituted in at least one ring, and conversely – none of the congeners that lacks 2,3,6-substitution could be separated. Thus, chiral recognition and enantiomer separation seems to be strongly governed by 2,3,6-substitution. 相似文献