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11.
Jane S. Murray Fakher Abu-Awwad Peter Politzer Leslie C. Wilson Allan S. Troupin Ryan E. Wall 《International journal of quantum chemistry》1998,70(6):1137-1143
The computed molecular surface electrostatic potentials of a group of anticonvulsants of various chemical types were investigated with the objective of identifying common features that may be related to their activities. The calculations were carried out with the density functional B3P86/6-31G* procedure, using HF/STO-3G*-optimized geometries. Analysis of several statistically based properties of the surface potentials indicates that the negative regions are of primary importance and that an optimum intermediate level of local polarity, or internal charge separation, is required. © 1998 John Wiley & Sons, Inc. Int J Quant Chem 70: 1137–1143, 1998 相似文献
12.
Project selection is a real problem of multicriteria group decision making (MCGDM) where each decision maker expresses his/her preferences depending on the nature of the alternatives and on his/her own knowledge over them. Thus, information, as much quantitative as qualitative, coexists. The traditional methods of MCGDM developed for project selection usually discriminates in favour of quantitative information at the expense of qualitative information, and this is due to the capability to integrate this first type of information inside their procedure. In this article, two new multicriteria 2-tuple group decision methods called “Preference Ranking Organisation Method for Enrichment Evaluation Multi Decision maker 2-Tuple-I and II” (PROMETHEE-MD-2T-I and II) are presented. They are able to integrate inside their procedure both quantitative and qualitative information in an uncertain context. This has been performed by integrating a 2-tuple linguistic representation model dealing with non-homogeneous and imprecise information data made up by valued intervals, numerical and linguistic values into the aggregation operators of Promethee methods. Although they have been developed for project selection problems, these proposed methods can be applied to all kinds of decision-making problems with heterogeneous and multigranular information. 相似文献
13.
Forecasting of the sea level plays a key role to control on- and offshore facilities. First, we start with a determinstic time series method based on the state space embedding to determine the vector field of the nonlinear dynamical system and deduce the solution of its corresponding high-order differential equation. Second, We assume that the sea state is a stochastic process governed by a deterministic part and by noise so that this dynamical system can be modelled by the Langevin equation. We extract the nonlinear dynamical system considering fluctuations directly from a measured time series by estimating the drift vector and the diffusion matrix of the Fokker-Planck equation. In order to determine the prediction accuracy, the numerical solutions of the deterministic model and the Langevin equation are compared to the data values at future time. (© 2011 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
14.
The crystal structures of the title compounds were solved using the single-crystal X-ray diffraction technique. At room temperature CsKSO4Te(OH)6 was found to crystallize in the monoclinic system with Pn space group and lattice parameters: ; ; ; β=106.53(2)°; ; Z=4 and . The structural refinement has led to a reliability factor of R1=0.0284 (wR2=0.064) for 7577 independent reflections. Rb1.25K0.75SO4Te(OH)6 material possesses a monoclinic structure with space group P21/a and cell parameters: ; ; ; β=106.860(10)°; ; Z=4 and . The residuals are R1=0.0297 and wR2=0.0776 for 3336 independent reflections. The main interest of these structures is the presence of two different and independent anionic groups (TeO66− and SO42−) in the same crystal.Complex impedance measurements (Z*=Z′—iZ″) have been undertaken in the frequency and temperature ranges 20-106 Hz and 400-600 K, respectively. The dielectric relaxation is studied in the complex modulus formalism M*. 相似文献
15.
Youssef Masmoudi Habib Chabchoub Saïd Hanafi Ahmed Rebaï 《Journal of Mathematical Modelling and Algorithms》2010,9(3):247-255
In this paper we propose a new procedure for classification based on a hybrid approach. The classification problem is solved
by minimizing the distance between the components of each clusters and the centers of the clusters. The determination of the
cluster centers is therefore a critical step in our approach and was addressed used the k-means algorithm. Once the centers
of each class are determined, the rule of center neighbourhood is applied to assign an element to a class using mathematical
programming. The implementation of our hybrid approach was validated on benchmark datasets and applied to an original biological
dataset on 84 breast cancer tumours. Each tumour was measured for five parameters corresponding to the expression of five
biomarkers (proteins). The obtained classification was discussed using biological knowledge and classical clinical experts’
classification of breast tumors. 相似文献
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17.
Fakher Chaari Tahar Fakhfakh Mohamed Haddar 《European Journal of Mechanics - A/Solids》2009,28(3):461-468
Due to excessive service load, inappropriate operating conditions or simply end of life fatigue, damage can occur in gears. When a fault, either distributed or localised, is incurred by gears, the stiffness and consequently vibration characteristics of the damaged tooth will change. In this work an analytical formulation of the time varying gearmesh stiffness was derived. An original analytical modelling of tooth cracks is presented and the gearmesh stiffness reduction due to this fault is quantified. A comparison with finite element model is presented in order to validate the analytical formulation. 相似文献
18.
Kamar Mkaouar Fakher Chabchoub Abdelouahid Samadi José Louis Marco Contelles Mansour Salem 《合成通讯》2013,43(22):3405-3414
Various imidates 3 were successfully synthesized from naphthopyrans and ethyl orthoesters in moderate yields. These intermediates undergo rapid condensation with several primary amines to give the corresponding 11-aryl-1,12-dihydro-11H-naphthopyrano[2,3-d] pyrimidin-12-ones 4. 相似文献
19.
A straightforward method has been developed for the synthesis of 1-phenyl-imidazo [2,1-c][1,2,4]triazole derivatives 5a–j and 1-phenyl-[1,2,4]triazolo[4,3-a]pyrimidinones derivatives 6a–g starting from 5-amino-1-phenyl[1,2,4]triazole and p-toluenesulfonic acid (PTSA). This methodology affords a number of 1-phenyl-imidazo [2,1-c][1,2,4]triazoles 5a–j and 1-phenyl-[1,2,4]triazolo[4,3-a]pyrimidinones 6a–g in reasonable yields and short reaction times. The structures of all new compounds were elucidated using infrared, 1H and 13C NMR, and high-resolution mass spectrometry. Some of the newly synthesized compounds were screened for their antimicrobial activity.
[Supplementary materials are available for this article. Go to the publisher's online edition of Synthetic Communications ® for the following free supplemental resource(s): Full experimental and spectral details.] 相似文献
20.
A numerical study of double-diffusive natural convection in an enclosure with a partial vertical heat and mass sources for an aspect ratio Ar = 4 has been carried out. The influence of various dimensionless parameters (Rayleigh number, buoyancy ratio, source location, Lewis number, and source length) on the flow behavior are investigated. Correlations of average Nusselt and Sherwood numbers are obtained as function of two parameters (Ra, d) and (Le, d), respectively. 相似文献