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G.R. Jahanshahloo F. Hosseinzadeh Lotfi N. Shoja A. Gholam Abri M. Fallah Jelodar Kamran Jamali Firouzabadi 《Mathematical and Computer Modelling》2011,53(5-6):587-596
One important issue in DEA which has been studied by many DEA researchers is the sensitivity of the results of an analysis to perturbations in the data.This paper develops a procedure for performing a sensitivity analysis of the inefficient decision making units (DMUs). The procedure yields an exact “Necessary Change Region” in which the efficiency score of a specific inefficient DMU changes to a defined efficiency score.In what follows, we identify a new frontier, and prove the efficiency score of each arbitrary unit on it which is defined as the efficiency score. 相似文献
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A. Gholam Abri G. R. Jahanshahloo F. Hosseinzadeh Lotfi N. Shoja M. Fallah Jelodar 《Optimization Letters》2013,7(2):309-324
Data envelopment analysis (DEA) evaluates the performance of decision making units (DMUs). When DEA models are used to calculate efficiency of DMUs, a number of them may have the equal efficiency 1. In order to choose a winner among DEA efficient candidates, some methods have been proposed. But most of these methods are not able to rank non-extreme efficient DMUs. Since, the researches performed about ranking of non-extreme efficient units are very limited, incomplete and with some difficulties, we are going to develop a new method to rank these DMUs in this paper. Therefore, we suppose that DMU o is a non-extreme efficient under evaluating DMU. In continue, by using “Representation Theorem”, DMU o can be represented as a convex combination of extreme efficient DMUs. So, we expect the performance of DMU o be similar to the performance of convex combination of these extreme efficient DMUs. Consequently, the ranking score of DMU o is calculated as a convex combination of ranking scores of these extreme efficient DMUs. So, the rank of this unit will be determined. 相似文献
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Several 2-alkyl-7-aryltetrahydro-1,6,2-dioxazepines 5a-i have been synthesized by a Meisenheimer-type rearrangement of 3-alkyl-2-aryltetrahydro-1,3-oxazine N-oxides 4a-i . These dioxazepines have not been previously described and for the first time compounds with the tetrahydro-1,6,2-dioxazepine ring-system have been made available. The structure assigned to members of this novel heterocycle is based on elemental analysis, infrared, and 1H nmr spectral evidence. Further definitive evidence for the structure of these heterocycles is provided by an X-ray crystallographic analysis of 5c . 相似文献
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One‐pot Synthesis of Novel 2,8‐dithioxopyrano[2,3‐d:6,5‐d′]dipyrimidine‐4,6(1H)‐dione Catalyzed by p‐Toluenesulfonic Acid
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N. O. Mahmoodi B. Sharifzadeh M. Mamaghani K. Tabatabaeian S. Shoja 《Journal of heterocyclic chemistry》2016,53(5):1646-1650
Novel 2,8‐dithioxopyrano[2,3‐d:6,5‐d′]dipyrimidine‐4,6(1H)‐dione derivatives were synthesized by a clean and efficient methodologies involving one‐pot regioselective and chemoselective reactions between two moles substituted thiobarbituric acid and 1 mol various aromatic aldehydes in the presence of p‐toluenesulfonic acid as a catalyst in EtOH with good yields in compression with alternative conditions such as microwave and promoted ultrasound. All of the compounds have been characterized by IR, 1H NMR, 13C NMR spectral data, and elemental analyses. 相似文献
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Research on Chemical Intermediates - A multi-functionalized Na-Y/ZnO/NH2/SH composite adsorbent was synthesized for Pb2+ and Ni2+ removal from single and binary aqueous systems. The prepared... 相似文献
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Morteza Hajizadeh-Oghaz Reza Shoja Razavi Ali Ghasemi 《Journal of Cluster Science》2016,27(2):469-483
Ceria–yttria co stabilized zirconia (CYSZ) was synthesized from solutions through the polymerizable complex method. The only difference in the preparation of the CYSZ samples was the pH of the starting solution, which was set at 1, 7 and 12, respectively. Transmission electron microscopy and scanning electron microscopy analysis revealed that the sample with the pH value of 1 had good homogeneity, low agglomeration, and a quasi-spherical shape with the particle size of 41 nm, while by increasing the pH up to 7 and 12, the particles became more disordered and no more in the range of nano sized materials (≤100 nm). Fourier transform infrared spectroscopy was employed to evaluate the bonding characteristics of the obtained gels at different pH values. thermogravimetric analysis, together with differential thermal analysis, was used to study the differences in the properties of dried gels with temperature. Crystallographic structure of the final product was also studied using X-ray diffraction. 相似文献
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Morteza Hajizadeh-Oghaz Reza Shoja Razavi Mohammad Reza Loghman-Estarki 《Journal of Sol-Gel Science and Technology》2014,70(1):6-13
A simple soft chemical method of synthesizing tetragonal yttria stabilized zirconia nanopowders is described here. Zirconium oxy-chloride octahydrate and yttrium nitrate hexahydrate were taken as a source of zirconium, citric acid was taken as a chelating agent, and ethylene glycol was used as a polysterification agent. The synthesized powders were characterized by X-ray diffraction, thermogravimetric analysis and differential scanning calorimetry, transmission electron microscopy, field emission scanning electron microscope, Fourier transform infrared spectroscopy and Raman spectroscopy. Furthermore, precise cell parameters were calculated in order to exactly determine non-transformable tetragonal crystal structure, which was the best zirconia phase for thermal barrier coatings applications. In this process, tetragonal yttria stabilized zirconia nanopowders could be prepared at a temperature of 1,000 °C and the process was simple and cost-effective. 相似文献