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排序方式: 共有56条查询结果,搜索用时 328 毫秒
1.
Ricerche di Matematica - Let D be an integral domain. G. Picozza associated to a stable semistar operation $$\star $$ on D, a semistar operation $$\star _1$$ on the polynomial ring D[X].... 相似文献
2.
The IR- and RAMAN -spectra are reported from OP(OCH3)2Cl, OP(OCH3)Cl2, SP(OCH3)Cl, SP(OCH3)Cl2. The assignement to the fundamental vibration is given and all Valence-force-constants are calculated. With increasing number of chlorine atoms decrease f P? OCH3 and f P? Cl. In the contrary, f O? P and f S? P increase. Here the influence of decreasing electro negativity is compensated by the change from an element of the first period of eight elements to an element of the second period. 相似文献
3.
Wafa B.E. Al-Othman Haitham M.S. Lababidi Imad M. Alatiqi Khawla Al-Shayji 《European Journal of Operational Research》2008
A multi-period stochastic planning model has been developed and implemented for a supply chain network of a petroleum organization operating in an oil producing country under uncertain market conditions. The proposed supply chain network consists of all activities related to crude oil production, processing and distribution. Uncertainties were introduced in market demands and prices. A deterministic optimization model was first developed and tested. The impact of uncertainty on the supply chain was studied by performing a sensitivity analysis in which ±20% deviations were introduced in market demands and prices of different commodities. A stochastic formulation was then proposed, which is based on the two-stage problem with finite number of realizations. The proposed stochastic programming approach proved to be quite effective in developing resilient production plans in light of high degree of uncertainty in market conditions. The anticipated production plans have a considerably lower expected value of perfect information (EVPI). The main conclusion of this study is that for an oil producing country with oil processing capabilities, the impact of economic uncertainties may be tolerated by an appropriate balance between crude exports and processing capacities. 相似文献
4.
5.
This paper describes different methods used to identify a large number of physical parameters of the thermo-hygro-mechanical coupling model. This model is developed on the basis of mechanics of porous media and deals with the prediction of response of a structure submitted to thermal, hygrometric and mechanical loading. The aim of this work is mainly to propose some experimental methods for the determination of physical parameters used previously in the model such as hygrometric parameters (liquid Biot's coefficient b
l
, vapour and liquid permeability v, l and tangent capillary modulus N
ll). Thermal parameters such as thermal conductivity (), specific heat (C) and the thermo-hydrous expansion coefficient (
i
p
) have been identified using some works published previously. The different physical parameters were identified in the case of cement mortar without taking into account the influence of hysteresis. 相似文献
6.
Structure and insertion properties of disordered and ordered LiNi0.5Mn1.5O4 spinels prepared by wet chemistry 总被引:1,自引:0,他引:1
We present the synthesis, characterization, and electrode behavior of LiNi0.5Mn1.5O4 spinels prepared by the wet-chemical method via citrate precursors. The phase evolution was studied as a function of nickel substitution and upon intercalation and deintercalation of Li ions. Characterization methods include X-ray diffraction, SEM, Raman, Fourier transform infrared, superconducting quantum interference device, and electron spin resonance. The crystal chemistry of LiNi0.5Mn1.5O4 appears to be strongly dependent on the growth conditions. Both normal-like cubic spinel [Fd3m space group (SG)] and ordered spinel (P4
1
32 SG) structures have been formed using different synthesis routes. Raman scattering and infrared features indicate that the vibrational mode frequencies and relative intensities of the bands are sensitive to the covalency of the (Ni, Mn)-O bonds. Scanning electron microscopy (SEM) micrographs show that the particle size of the LiNi0.5Mn1.5O4 powders ranges in the submicronic domain with a narrow grain-size distribution. The substitution of the 3d8 metal for Mn in LiNi0.5Mn1.5O4 oxides is beneficial for its charge–discharge cycling performance. For a cut-off voltage of 3.5–4.9 V, the electrochemical capacity of the Li//LiNi0.5Mn1.5O4 cell is ca. 133 mAh/g during the first discharge. Differences and similarities between LiMn2O4 and LiNi0.5Mn1.5O4 oxides are discussed. 相似文献
7.
8.
9.
The aim of this paper is to prove an uncertainty principle for the basic Bessel transform of order
. In order to obtain a sharp uncertainty principle, we introduce and study a generalized q-Bessel-Dunkl transform which is based on the q-eigenfunctions of the q-Dunkl operator newly given by:
In this work, we will follow the same steps of Fitouhi et al. (Math. Sci. Res. J., 2007) using the operator T
α,q
instead of the q-derivative.
相似文献
10.
Raghuram Reddy Kothur Flavia Fucassi Gennaro Dichello Ludovic Doudet Wafa Abdalaziz Bhavik Anil Patel 《Supramolecular chemistry》2016,28(5-6):436-443
AbstractA novel copillar[4+1]arene incorporating alkylthiol substituents was synthesised in three steps and structurally characterised as the first example of a pillar[n]arene to incorporate two terminal thiols on the same aromatic ring. The macrocycle was attached to gold electrodes through a standard dipping technique. Cyclic voltammetry demonstrated selectivity for Li+ over other alkali metal cations. The copillar[4+1]arene was also used as a capping agent in the preparation of 3 nm gold nanoparticles. 相似文献