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61.
This note presents a variation of the well-known Silver–Meal heuristic to deal with lot sizing under a combination of a known, but time-varying, demand pattern along with an incremental quantity discount structure. The heuristic is shown to perform very well on a set of experiments presented in a recent paper in this journal. Additional experiments are performed to further explore the time horizon effects on the relative performance of the newly proposed heuristic compared to the two best performing ones from the previous paper. 相似文献
62.
Haihong Fang Binyuan Hu Lingshen Wang Rongli Lu Cui Yang 《Frontiers of Chemistry in China》2008,3(2):193-197
Nanometer MgO was prepared via a sol-gel auto-combustion technique using magnesium nitrate as raw material and citric acid
as chelating agent. IR spectra of the dried gel were used to investigate the structure of the precursors. By studying the
different TG curves of magnesium citrate gel prepared by different methods, we found that a combustion process occurred and
the nitrate ions acted as an oxidant in the combustion process. TEM photographs of synthesized powders from the sol-gel auto-combustion
showed that the crystallites were uniform in size. In addition, the XRD pattern of this sample showed that the particle size
was 8.9 nm. The BET curves, in turn, showed that the specific surface of the sample was 26.34 m2/g. The mechanism of the frothing process in restraining agglomeration is discussed.
__________
Translated from Journal of East China Normal University (Natural Science), 2007, (2): 52–57 [译自: 华东师范大学学报(自然科学版)] 相似文献
63.
Wenping Deng Gang Xu Lei Wan Anwen Liu Bo Gao Junhe Du Shuiming Hu Yang Chen 《Acta Physico》2008,24(8):1329-1334
Apparatus integrating a Fourier transform-infrared (FT-IR) spectrometer and a mid-infrared difference frequency generation (DFG) laser spectrometer was built for the study of the matrix isolation spectrum in solid molecular hydrogen. A 3-cm-long molecular hydrogen crystal was grown in a liquid-helium Dewar, and its infrared absorption spectrum in the 1-5 μm region was recorded to test the system. The W0(0) (ν=0←0, J=6←0) line around 2410 cm−1 of solid hydrogen was investigated with the DFG laser spectroscopy. High-resolution matrix isolation spectrum of CO2 co-deposited with hydrogen on a BaF2 cold plate at liquid-helium temperature was studied. 相似文献
64.
65.
Two homologous series of mesogenic materials which incorporate a 1,4-tetrafluorophenylene moiety and a terminal cyano- or nitro-substituent have been synthesized by using palladiumcatalysed coupling procedures. The compounds exhibit nematic and/or smectic A phases. 相似文献
66.
本文研究弱一致Opial条件的性质;弱一致Opial条件与弱一致Opial条件的对偶性;证明当对偶空间有弱一致Opial条件时该Banach空间具有不动点性. 相似文献
67.
The performance evaluation of many complex manufacturing, communication and computer systems has been made possible by modeling
them as queueing systems. Many approximations used in queueing theory have been drawn from the behavior of queues in light
and heavy traffic conditions. In this paper, we propose a new approximation technique, which combines the light and heavy
traffic characteristics. This interpolation approximation is based on the theory of multipoint Padé approximation which is
applied at two points: light and heavy traffic. We show how this can be applied for estimating the waiting time moments of
the GI/G/1 queue. The light traffic derivatives of any order can be evaluated using the MacLaurin series analysis procedure. The heavy
traffic limits of the GI/G/1 queue are well known in the literature. Our technique generalizes the previously developed interpolation approximations
and can be used to approximate any order of the waiting time moments. Through numerical examples, we show that the moments
of the steady state waiting time can be estimated with extremely high accuracy under all ranges of traffic intensities using
low orders of the approximant. We also present a framework for the development of simple analytical approximation formulas.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
68.
该文用顺磁离子对其近邻~(13)C核的NMR吸收增宽效应,系统地研究了抗坏血酸在不同溶剂中对金属离子Mn~(2+)、Gd~(3+)的配合行为.在水溶液中,抗坏血酸可通过两种配合方式与Mn~(2+)作用,但与Gd~(3+)的作用只有一种稳定的结构.在水中抗坏血酸对金属的配位活性部位分别是1位羟基氧,3位离解的羟基氧和6位羟基氧.在DMSO中,3位羟基由于H~+对该基团的静电遮蔽而变得对金属离子Mn~(2+)表现为配位惰性,同时6位羟基配位活性较大增强.对Gd~(3+)来说,此时没有优势配位活性部位存在.文章还讨论了抗坏血酸在H_2O-DMSO混合溶剂中的~(13)C NMR谱及在DMSO中NaOH对其~(13)C NMR谱及其与金属络合结构的影响. 相似文献
69.
玻色—爱因斯坦凝聚和兰姆位移 总被引:1,自引:0,他引:1
扼要地介绍了BEC研究的近况和研究方向,同时报道了我们在BEC的光散射和兰姆位移方面的研究工作 相似文献
70.