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21.
There is a general interest in ranking schemes applied to complex entities described by multiple attributes. Published rankings
for universities are in great demand but are also highly controversial. We compare two classification and ranking schemes
involving universities; one from a published report, ‘Top American Research Universities’ by the University of Florida's TheCenter and the other using DEA. Both approaches use the same data and model. We compare the two methods and discover important equivalences.
We conclude that the critical aspect in classification and ranking is the model. This suggests that DEA is a suitable tool
for these types of studies. 相似文献
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24.
Characteristic features of reactions involving esters of phosphorus-containing acids in highly organized media (micelles, liquid crystals, vesicles, and emulsions) are surveyed.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 298–312, February, 1996. 相似文献
25.
Gun'ko V. M. Mikhalovskii S. V. Melillo M. Voronin E. F. Nosach L. V. Pakhlov E. M. 《Theoretical and Experimental Chemistry》2004,40(3):137-143
The interaction of ibuprofen [2-(4-isobutylphenyl)propionic acid] with the surface of carbon and oxide adsorbents was investigated. The significant role of wide pores during the adsorption of ibuprofen on carbon adsorbents in the presence of protein molecules was demonstrated. At low concentrations ibuprofen is adsorbed on the surface of hydrophilic and hydrophobic adsorbents in the form of a monomer, but the contribution from the adsorbed dimer increases with increase in its concentration. 相似文献
26.
《Electroanalysis》2006,18(11):1081-1089
This paper describes the voltammetric behavior of As(III) at the hanging mercury drop electrode (HMDE) in the presence of sodium diethyl dithiocarbamate (SDDC) and a new voltammetric method for the determination of As(III) at trace levels. The method is based on the adsorptive deposition of a As(III) complex with SDDC at ?0.45 V (vs. Ag/AgCl) on the HMDE in acidic medium of 0.01 mol L?1 HCl (pH 2.0) and its cathodic stripping during the potential scan (100 mV s?1). The linear range for the determination of As(III) in the presence of SDDC (4 μmol L?1) in water samples was between 1 and 10 μg L?1 for a deposition time of 300 s (r=0.994) and between 10 and 100 μg L?1 for a deposition time of 60 s (r=0.999). For the determination of As(III) in dialysis concentrate samples, the linear range was between 5 and 25 μg L?1 for a deposition time of 180 s (r=0.992) and between 10 and 100 μg L?1 for a deposition time of 60 s (r=0.996). Detection limits of 0.3 and 2.2 μg L?1 in water and dialysis concentrate samples were calculated for the method using a deposition time of 300 and 180 s, respectively. Recovery values between 93.0 and 110.0% for As(III) added to deionized, mineral, seawater (synthetic and real) and dialysis concentrate samples prove the satisfactory accuracy and applicability of the procedure. 相似文献
27.
A. S. Said 《Journal of separation science》1979,2(2):63-67
The theory of composite chromatographic columns has been re-examined and general equations relating their efficiency to those of individual columns were derived. The derivations were based on elementary principles without reference to the principle of variance additivity. Derived also, were general equations for the efficiency of columns with continuously varying diameters, HETP and other properties from which formulae for special cases of practical interest were deduced. An example comparing the efficiencies of two columns, one conical and the other composite was given. The calculations show clearly that the conical column is superior in efficiency for the same total length and total retention volume. 相似文献
28.
This paper presents in detail a robust, efficient and accurate methodology for the computation of equilibrium composition in gaseous mixtures. The methodology is founded on the concept of the chemical basis, which is defined and formalized using a powerful matricial approach. The method is specially designed to be general, thus providing basic thermodynamic data in several areas, such as combustion, plasma chemistry and, more generally speaking, computational fluid dynamics. The performance of the method is given in terms of CPU usage and the computed results are compared with those in the published literature. The method is shown to yield results of very high quality in terms of accuracy and smoothness. 相似文献
29.
Synthesis of Highly Porous Organic/Inorganic Hybrids by Ambient Pressure Sol-Gel Processing 总被引:6,自引:0,他引:6
This paper reports the synthesis of highly porous organic/inorganic hybrids by a two-step acid-base catalyzed sol-gel process and ambient pressure drying. In the method organic and inorganic precursors are copolymerized so as to incorporate organic ligands into the solid network. The two-step acid-base catalyzed process was used to prevent phase segregation during the hydrolysis and co-condensation of organic and inorganic precursors. The organic ligands incorporated into the solid gel network modify the surface chemistry. Thus, the wetting angle is significantly increased so that the collapse of the gel network is greatly reduced upon the removal of pore fluid during drying. Organic/inorganic hybrids with BET surface areas above 1250 m2/g, porosities above 75% and pore sizes of 8 nm have been synthesized. 相似文献
30.
B. F. Myasoedov L. A. Gribov A. I. Pavlyuchko I. V. Rybalchenko G. I. Sigeikin A. F. Kireev V. N. Suvorkin 《Journal of Structural Chemistry》2006,47(3):434-441
For highly toxic organophosphorus compounds on the limiting lists of the International Chemical Weapons Ban Treaty, fragment methods may be used for calculating their IR vibrational spectra; this is shown for O-alkyl alkylfluorophosphonates used as examples. The geometrical parameters and the parameters of the potential and electrooptic functions are found for the major fragments of these compounds. Due to this, fast predictive computation of IR spectra of O-alkyl alkylfluorophosphonates is possible, the accuracy of calculation being sufficient for spectral identification of these compounds; a database of the calculated IR spectra may be created. 相似文献