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101.
L. Mohammadzadeh A. Asgari S. Shojaei E. Ahmadi 《The European Physical Journal B - Condensed Matter and Complex Systems》2011,84(2):249-253
In this paper the excitons of armchair graphene nanoribbons with layers of different width and thickness have been investigated.
In this investigation, the band structure and energy gap of armchair graphene nanoribbons have been calculated using a tight-binding
model including edge deformation effects (all edge atoms have been passivated with hydrogen atoms). Also, by calculating the
conductance in armchair graphene nanoribbons (A-GNRs) optical absorption of armchair graphene nanoribbon in the single-electron
approximation has been obtained. Finally, the binding energy of excitons in armchair graphene nanoribbons has been calculated
using the Wannier model, Hartree-Fock approximation and the Bethe-Salpeter equation. 相似文献
102.
M. Eskandari N. HaghighiV. Ahmadi F. HaghighiSH.R. Mohammadi 《Physica B: Condensed Matter》2011,406(1):112-114
In this study, we have investigated the antifungal activity of ZnO nanorods prepared by the chemical solution method against Candida albicans. In the study, Zinc oxide nanorods have been deposited on glass substrates using the chemical solution method. The as-grown samples are characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD). X-ray diffraction (XRD) showed zinc oxide nanorods grown in (0 0 2) orientation. The antifungal results indicated that ZnO nanorod arrays exhibit stable properties after two months and play an important role in the growth inhibitory of Candida albicans. 相似文献
103.
Gerhard Post Jeffrey H. Kingston Samad Ahmadi Sophia Daskalaki Christos Gogos Jari Kyngas Cimmo Nurmi Nysret Musliu Nelishia Pillay Haroldo Santos Andrea Schaerf 《Annals of Operations Research》2014,218(1):295-301
We present the progress on the benchmarking project for high school timetabling that was introduced at PATAT 2008. In particular, we announce the High School Timetabling Archive XHSTT-2011 with 21 instances from 8 countries and an evaluator capable of checking the syntax of instances and evaluating the solutions. 相似文献
104.
A multiobjective binary integer programming model for R&D project portfolio selection with competing objectives is developed when problem coefficients in both objective functions and constraints are uncertain. Robust optimization is used in dealing with uncertainty while an interactive procedure is used in making tradeoffs among the multiple objectives. Robust nondominated solutions are generated by solving the linearized counterpart of the robust augmented weighted Tchebycheff programs. A decision maker’s most preferred solution is identified in the interactive robust weighted Tchebycheff procedure by progressively eliciting and incorporating the decision maker’s preference information into the solution process. An example is presented to illustrate the solution approach and performance. The developed approach can also be applied to general multiobjective mixed integer programming problems. 相似文献
105.
K. Ahmadi F. Hasani B. Kheirfam 《Journal of Mathematical Modelling and Algorithms》2014,13(2):191-208
We present a full-Newton step primal-dual infeasible interior-point algorithm based on Darvay’s search directions. These directions are obtained by an equivalent algebraic transformation of the centering equation. The algorithm decreases the duality gap and the feasibility residuals at the same rate. During this algorithm we construct strictly feasible iterates for a sequence of perturbations of the given problem and its dual problem. Each main iteration of the algorithm consists of a feasibility step and some centering steps. The starting point in the first iteration of the algorithm depends on a positive number ξ and it is strictly feasible for a perturbed pair, and feasibility steps find strictly feasible iterate for the next perturbed pair. By using centering steps for the new perturbed pair, we obtain strictly feasible iterate close to the central path of the new perturbed pair. The algorithm finds an ?-optimal solution or detects infeasibility of the given problem. The iteration bound coincides with the best known iteration bound for linear optimization problems. 相似文献
106.
Seyed Jalal Hosseinimehr Amirhossein Ahmadi Reza Taghvai 《Journal of Radioanalytical and Nuclear Chemistry》2010,284(3):563-566
Free radicals and oxidative stress are the primary causes of several chronic diseases such as cancer and heart disease. Quercetin
is a natural compound with potent antioxidant activity. We have prepared and evaluated technetium-99m (99mTc)-labeled quercetin as a potential radical scavenging radiotracer. A 99mTc-quercetin complex was prepared using quercetin, SnCl2 and Na99mTcO4 in a buffered solution over 30 min. The participation coefficient was measured in octanol and queues solutions. The stability
was determined in phosphate buffered saline and serum. The biodistribution in normal mice was evaluated at 0.5, 2, 6 and 24 h
post-injection. The radiochemical purity (>99%) was determined by thin layer chromatography (TLC) in normal saline solution
as the mobile phase. It has a log P of 0.204. It was mainly cleared by the kidneys and showed negligible brain uptake at four time points measured post-injection.
The pharmacological properties of quercetin, mainly its free radical scavenging, may potentially cat as a radiopharmaceutical
agent for radical-targeted imaging of tissue with high levels of reactive oxygen species. 相似文献
107.
Zeinab Noroozi TissehFereshteh Ahmadi Minoo DabiriHamid Reza Khavasi Ayoob Bazgir 《Tetrahedron letters》2012,53(28):3603-3606
A practical, simple, and efficient method for the synthesis of pyrano-fused spirooxindoles via an organocatalytic three-component reaction of isatins, malononitrile, and dialkyl acetylenedicarboxylate in the presence of 3,4-dimethylaniline as an organocatalyst in ethanol is reported. The structures of these products are confirmed by IR, 1H NMR and 13C NMR spectroscopy, mass spectrometry, and single-crystal X-ray diffraction studies. 相似文献
108.
This paper was published online on 10 October 2008 (DOI: 10.1002/pat.1279 ) and appears in the January 2009 issue (Vol. 20, No. 1, pp. 48‐57). The following changes should be recognized: The second corresponding author should be changed to M. Rafiena. ** Correspondence to: M. Rafienia, Medical Physics and Medical Engineering Department, Isfahan University of Medical Sciences (IUMS), P.O. Box 81744‐176, Isfahan, Iran. E‐mail: m_rafienia@med.mui.ac.ir 相似文献
109.
In the Capacitated Clustering Problem (CCP), a given set of n weighted points is to be partitioned into p clusters such that, the total weight of the points in each cluster does not exceed a given cluster capacity. The objective is to find a set of p centers that minimises total scatter of points allocated to them. In this paper a new constructive method, a general framework to improve the performance of greedy constructive heuristics, and a problem space search procedure for the CCP are proposed. The constructive heuristic finds patterns of natural subgrouping in the input data using concept of density of points. Elements of adaptive computation and periodic construction–deconstruction concepts are implemented within the constructive heuristic to develop a general framework for building efficient heuristics. The problem-space search procedure is based on perturbations of input data for which a controlled perturbation strategy, intensification and diversification strategies are developed. The implemented algorithms are compared with existing methods on a standard set of bench-marks and on new sets of large-sized instances. The results illustrate the strengths of our algorithms in terms of solution quality and computational efficiency. 相似文献
110.
We obtain criteria of stability of the unsteady motion of an incompressible Cosserat fluid in an arbitrary time-dependent domain, employing a general energy method due to J. Serrin. It is shown that the original motion is stable if R
e
2
80 + 12800 C
0 or if R
e80 + 6400 C
0. The quantities R
e and C
0 are the Reynolds number and Cosserat number, respectively, and - is the lower bound for the eigenvalues of the strain rate tensor D
ij.The theorems established for the stability criteria are universal in the sense that they do not depend either on the shape of the domain or on the distribution of the basic field variables. Finally an experimental scheme is proposed to determine the upper bound of the Cosserat number and consequently the characteristic length of a Cosserat fluid. 相似文献