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971.
The main purpose of this paper is to discuss the asymptotic behaviour of the difference s
q,k(P(n)) - k(q-1)/2 where s
q,k (n) denotes the sum of the first k digits in the q-ary digital expansion of n and P(x) is an integer polynomial. We prove that this difference can be approximated by a Brownian motion and obtain under special
assumptions on P, a Strassen type version of the law of the iterated logarithm. Furthermore, we extend these results to the joint distribution
of q
1-ary and q
2-ary digital expansions where q
1 and q
2 are coprime.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
972.
973.
Wang Shijie 《新疆大学学报(理工版)》1995,(3)
QuicklyDrawingAnAreaFromaDigitalImageWangShijie(Dept.ofElectronits,XinjiangUniversity,Urumqi830046)QuicklyDrawingAnAreaFromaD... 相似文献
974.
本探讨了一种用于静电陀螺的小角度光电信号读出的全数字方案,通过对比、分析和讨论,说明数字化静电陀螺小角度读出方案的优越性,并提出了针对静电陀螺光电读出系统随机误差的修正算法。 相似文献
975.
数字重建编码成像的迭代算法 总被引:1,自引:1,他引:0
用矩阵方法研究数字重建编码成像的迭代方法,为克服问题的不唯一与病态,采用正规化方法,给出正视化迭代解码算法,分析了算法的收敛性,与真解的关系,所得的正规解可以抑制噪声,但不能安全反映物体的局域性质,文中分析了算法的计算复杂性,指出巨大的计算要求是限制其实用的关键因素。 相似文献
976.
利用分形图形具有无限可分和比例尺度上的自相似的特征以及可以产生无限变量重复码的特点,通过计算机控制激光双光束干涉光刻成点阵全息光栅,从而形成数字像素全息图.构造出分形图形的迭代函数系统框架,形成丰富多彩,变化多端的分形图形,以此对点阵全息光栅编码,光刻成分形数字像素全息图. 相似文献
977.
Duringthelastfifteenyears,microelectrodeswhosedimensionsarelessthanamillimeterhavebeenintroducedintoforcedconvectionsystems[1,2].Theinterestingfieldsofforcedconvectionmicroelectrodeshaveextendedtostudyingthekineticsofelectrodeprocesses[2]fromthedetectorof… 相似文献
978.
Bieniasz LK 《Journal of computational chemistry》2004,25(8):1075-1083
The fourth-order accurate, three-point finite-difference Numerov spatial discretization provides accurate and efficient solutions to the time-dependent governing differential equations of electrochemical kinetics in one-dimensional space geometry, when the equations contain first time derivatives of the solution, second spatial derivatives, and homogeneous reaction terms only. However, the original Numerov discretization is not applicable when the governing equations involve first spatial derivative terms. To overcome this limitation, an appropriately extended Numerov discretization is required. We examine the utility of one of such extensions, first described by Chawla. Relevant discrete formulae are outlined for systems of linear governing equations involving first derivative terms, and applied to five representative example models of electrochemical transient experiments. The extended Numerov discretization proves to have an accuracy and efficiency comparable to the original Numerov scheme, and its accuracy is typically up to four orders of magnitude higher, compared to the conventional, second-order accurate spatial discretization, commonly used in electrochemistry. This results in a considerable improvement of efficiency. Therefore, the application of the extended Numerov discretization to the electrochemical kinetic simulations can be fully recommended. 相似文献
979.
Three C(60) derivatives, 1, 2 and 3, have been studied by cyclic voltammetry (CV) under high vacuum in anhydrous tetrahydrofuran (THF). The CV behavior was essentially similar to that already observed for other cyclopropanated fullerene derivatives. After the second reduction processes all compounds undergo a chemical reaction that generates another electroactive species. This "new" chemical species is likely to be the compound with the cyclopropane ring open. Differences in CV behavior were observed for the different addends. Electrochemical data obtained at different scan rates for a given potential window, were fit with the BAS digital simulation program, DigiSim. The purpose of this study was to probe the proposed mechanisms and to obtain reliable estimations of the kinetic constants for the homogeneous chemical reactions taking place during the CV experiments. Calculations at the PM3 level lend additional support to the conclusions derived from digital simulations. The proposed mechanism is similar for all the compounds and involves two main chemical reactions in a reversible square scheme. 相似文献
980.
Ding L Sudakov M Brancia FL Giles R Kumashiro S 《Journal of mass spectrometry : JMS》2004,39(5):471-484
In a digital ion trap (DIT), the quadrupole trapping and excitation waveforms are generated by the rapid switching between discrete d.c. voltage levels. As the timing of the switch can be controlled precisely by digital circuitry, the approach provides an opportunity to generate mass spectra by means of a frequency scan in contrast to the conventional voltage scan, thus providing a wider mass range of analysis. An instrument has been constructed which employs a 'non-stretched' ion trap and the field fault around the aperture of the end-cap electrode can be corrected electronically using a field-adjusting electrode. The ion trap was coupled with electrospray ionization (ESI) and atmospheric pressure matrix-assisted laser desorption/ionization (AP-MALDI) sources to demonstrate the capability of the digital method. AP-MALDI mass spectra of singly charged ions with mass-to-charge ratios upto 17 000 Th were generated using a trapping voltage of only 1000 V. Forward and reverse mass scans at resolutions up to 19 000 and precursor ion isolation at resolutions up to 3500 with subsequent tandem mass spectrometric analysis were demonstrated. The method of generating the digital waveforms and period scan is described. Discussion of the issues of mass range, scan speed, ion trapping efficiency and collision-induced dissociation efficiency are also provided. 相似文献