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91.
92.
A reversed-phase gradient elution, UV detection method is developed for the simultaneous determination of mono (2-ethylhexyl) phthalate [MEHP] and di (2-ethylhexyl) phthalate [DEHP] in tissue samples. The method is validated with respect to extraction recovery, inter and intra-day precision, linearity of response, detect ability, and specificity. The validated method has been successfully applied to the study of DEHP and MEHP in liver, kidney, testis, brain, and plasma samples from rat. 相似文献
93.
The effects of the sorption and the regeneration temperatures on the performance of a novel rapid thermal swing chemisorption
(RTSC) process (Lee and Sircar in AIChE J. 54:2293–2302, 2008) for removal and recovery of CO2 from an industrial flue gas without pre-compression, pre-drying, or pre-cooling of the gas were mathematically simulated.
The process directly produced a nearly pure, compressed CO2 by-product stream which will facilitate its subsequent sequestration. Na2O promoted alumina was used as the CO2 selective chemisorbent, and the preferred temperatures were found to be, respectively, 150 and 450 °C for the sorption and
regeneration steps of the process. The specific cyclic CO2 production capacity of the process and the pressure of the by-product CO2 gas were substantially increased over those previously achieved by using the sorption and regeneration temperature of, respectively,
200 and 500 °C (Lee and Sircar in AIChE J. 54:2293–2302, 2008). The net compressed CO2 recovery from the flue gas (∼92%) did not change. However, substantially different amounts of high and low pressure steam
purges were necessary for comparable degree of desorption of CO2. A first pass estimation of the capital and the operating costs of the RTSC process was carried out for a relatively moderate
size application (flue gas clean up and CO2 recovery from a ∼80 MW coal fired power plant). Both costs were substantially lower than those for a conventional absorption
process using MEA as the CO2 solvent (Desideri and Paolucci in Energy Convers. Manag. 40:1899–1915, 1999). 相似文献
94.
Metallo-guanines of the type [M(G)2·2H2O] [M = NiII, FeII, CuII and UO2
II; G = anionic guanine], [M(G)2(GH)· H2O] (M = CoII and MnII; GH = neutral guanine), [Pd(G)2]·2H2O and [Zn(G)Cl]2 have been isolated and characterised. Anionic guanine functions as a bidentate ligand and links through N(3) and N(9). E.p.r. data indicate that the CuII complex has a highly distorted octahedral structure. The magnetic susceptibility data suggest that the CoII and NiII complexes possess pseudooctahedral geometry. Neutral guanines are probably unidentate and coordinate either through N(3) or N(9). The isolated guanosine complexes are of the types: [M(Gs)2·H2O] [M = NiII and CuII, Gs = anionic guanosine] [Pd(Gs)2]·2H2O and [UO2(Gs)2]. I.r. data indicate that guanosine also functions as a bidentate ligand, but coordinates through N(1) and C2 — NH2. The electronic absorption spectra of the complexes indicate that guanine is a stronger ligand than guanosine. 相似文献
95.
High pressure adsorption measurements for light gases on volumetric equipment are prone to error. Differential units reduce the sensitivity to leakage, gas compressibility, and temperature gradients, but remain highly sensitive to volume uncertainties, the calibration of which is difficult in the presence of low-density, microporous samples. Calibration error can be reduced using a high initial pressure differential and large calibration volume; however, systematic error is prevalent in the literature. Using both analytical and multivariate error analysis, we demonstrate that calibration of the differential unit with the differential pressure transducer significantly decreases volume sensitivity. We show that hydrogen adsorption to GX-31 superactivated carbon at 298 K and 80 bar can be measured with a 7 % error in measurement (i.e. within 0.05 wt% for a 100 mg sample), even when experimental volume calibration is determined only within ~1 %. This represents approximately a 2–7 fold increase in sensitivity relative to previous reports using differential measurements. We also provide a framework for optimizing the design of a volumetric adsorption unit. For virtually any system design, the improved differential methods offer a significant increase in precision relative to the conventional volumetric measurement (from 10- to over 250-fold, depending on the precision of the pressure transducer). This improvement further enhances advantages of the differential unit, in addition to advantages that arise for treating gas compressibility and temperature fluctuations. 相似文献
96.
97.
A highly regioselective conversion of DHP
to DHP
has been achieved for the first time in high yield. Treatment of the bromide
with different nucleophiles under basic conditions produced 2-substituted 1,4-dihydropyridines in high yields and purity. 相似文献
98.
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100.