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991.
Diverse existing lines for the calculation of excited states are exposed, with an emphasis on those methods that consider
both types of correlation energy: the dynamic and the non-dynamic one. We analyze the possibility of to calculate the dynamic
correlation energy using a correlation energy density functional applied to a multi-determinantal wavefunction, which would
include the non-dynamic correlation energy, versus the use of mono-determinantal wavefunctions, which are not able to include
the long-range correlation energy, and versus the use of variational or perturbative calculations from multi-determinantal
wavefunctions, with their excessive computational cost. The results obtained with several methods are compared.
Contribution to the Serafin Fraga Memorial Issue. 相似文献
992.
Immunoassays have traditionally relied on antibodies as diagnostic probes. Their use outside of a laboratory, however, may be problematic because antibodies are often unstable in severe environmental conditions. Environmental monitoring requires thermostable probes, such as landscape phage, that carry thousands of foreign peptides on their surfaces, are superior to antibodies, and can operate in non-controlled conditions. While parent wild-type phage are known to be extremely stable in various media at high temperatures, no work has been done to demonstrate the stability of landscape phage probes. We examined the thermostability of a landscape phage probe and a monoclonal antibody specific for -galactosidase in parallel in an enzyme-linked immunosorbent assay (ELISA) format. They were both stable for greater than six months at room temperature, but at higher temperatures the antibody degraded more rapidly than the phage probe. Phage retained detectable binding ability for more than six weeks at 63 °C, and three days at 76 °C. The activation energy of phage degradation was determined to be 1.34×105 J/mol. These results confirm that phage probes are highly thermostable and can function even after exposure to high temperatures during shipping, storage and operation. 相似文献
993.
This paper reports the development of a method based on capillary electrophoresis with laser-induced fluorescence detection for the simultaneous determination of thiouracil (TU) and phenylthiouracil (PhTU) with high sensitivity (nanomolar range, i.e., attomoles detected). After derivatization with 5-iodoacetamidofluorescein, the analytes were separated by capillary zone electrophoresis using 20 mM phosphate buffer (pH 10.0) and quantified by fluorescence detection. The linearity range, precision, recovery, and detection limits were determined, and the method was shown to be applicable for the determination of TU and PhTU in spiked feed samples and urine. 相似文献
994.
We investigate the regular and moving Liesegang pattern formation phenomena in an open system. First, simulations have been performed at fixed coupling between the reactive medium and the reservoir, later this control parameter was varied during the simulations resulting in various phenomena. We predicted and monitored for the first time various--dynamically changing--precipitation structures and a spatial hysteresis phenomenon, which is beyond the scope of the Turing instability. The dynamics of the reaction is well detectable using specific quantities: the total amount of precipitate and its center of gravity. 相似文献
995.
P. Rajec F. Macášek M. Féder P. Misaelides E. Šamajová 《Journal of Radioanalytical and Nuclear Chemistry》1998,229(1-2):49-55
The sorption of caesium and strontium from its aqueous solutions by ten clinoptilolite-and mordenite-containing sedimentary
materials from Slovakia, Bulgaria, Ukraine and Greece was investigated by batch-type procedure and radiotracer techniques.
The concentration of the solutions, that were performed in and without the presence of competing cations (0.005 mol·dm−3 KCl) varied between 1·10−4 and 5·10−2 mol·dm−3. The uptake and distribution coefficient (K
d
) values determined for the materials of the different origin, were correlated with their mineralogical composition and gross
cation exchange capacity (CEC). The identification of the specific uptake sites was attempted on the basis of the sorption
isotherms and the content of exchangeable cations. The experimental results provide information on the suitability of the
individual materials for the treatment of radioactive wastes and their application as backfills in potential nuclear waste
repositories. 相似文献
996.
J. Rodriguez-Añón J. Prouupin M. González-Añón L. Núñez-Regueira 《Journal of Thermal Analysis and Calorimetry》1998,52(3):1005-1012
The heating values of municipal solid waste generated in three towns with a population of less than 50 000, situated in Galicia
(Spain), were measured with a static bomb calorimeter. Samples of raw refuse were burnt either as received or after sorting
of the different combustible components. A study was made of samples from controlled and uncontrolled landfills.
The calorific values were compared with those corresponding to a commercial residual derived fuel in order to study the possibility
of using municipal solid waste as a source of recovered energy.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
997.
The fact that bitumens behave as non-Newtonian fluids results in non-linear relationships between their near-infrared (NIR) spectra and the physico-chemical properties that define their consistency (viz. penetration and viscosity). Determining such properties using linear calibration techniques [e.g. partial least-squares regression (PLSR)] entails the previous transformation of the original variables by use of non-linear functions and employing the transformed variables to construct the models. Other properties of bitumens such as density and composition exhibit linear relationships with their NIR spectra. Artificial neural networks (ANNs) enable modelling of systems with a non-linear property-spectrum relationship; also, they allow one to determine several properties of a sample with a single model, so they are effective alternatives to linear calibration methods. In this work, the ability of ANNs simultaneously to determine both linear and non-linear parameters for bitumens without the need previously to transform the original variables was assessed. Based on the results, ANNs allow the simultaneous determination of several linear and non-linear physical properties typical of bitumens. 相似文献
998.
A complete strategy for the isolation of individual mono- and disialogangliosides has been elaborated. We have used straight-phase silica gel chromatography or partitioning to obtain a crude ganglioside fraction. This fraction was then peracetylated and run through a second silica gel column. After anion-exchange chromatography the gangliosides were separated by straight-phase high-performance liquid chromatography with chloroform-methanol-water mixtures as eluting solvents. The method is suitable for preparative isolation of gangliosides and subsequent structural characterization by thin-layer chromatography-enzyme-linked immunosorbent assay, fast atom bombardment mass spectrometry and/or gas chromatography-mass spectrometry, which is demonstrated by several examples, including the separation of GalNAc-II3NeuAc-GgOse4Cer from GalNAc-isoII3NeuAc-GgOse4Cer. 相似文献
999.
An electrochemical method for the determination of the ionophores monensin and lasalocid was developed, based on the polarization of an agar gel/nitrobenzene electrolyte interface. The measured current corresponding to the facilitated ion transfer across this interface is directly proportional to the concentration of an ionophore dissolved in the organic phase. Using cyclic voltammetry in a three-electrode system the detection limit for both ionophores is about 3 × 10?5 M. 相似文献
1000.
V. Suchá 《Journal of Thermal Analysis and Calorimetry》1990,36(3):1113-1121
The study of thermal properties of La(HV6O16)3.19.5H2O and Y(HV6O16)3.22H2O showed, that the dehydration of both compounds is discontinuous. After release of last water amount, the parent structure is destabilized and products of thermal decomposition, V2O5 and corresponding orthovanadates, start to be formed. The decomposition of La(HV6O16)3.19.5H2O results in formation of V2O5 and LaVO4, the temperatures of crystallization of which differ. The decomposition products of yttrium salt crystallize simultaneously. All compounds formed melt at 685°C. By crystallization of the melt, the mixtures V2O5-LaVO4 and V2O5-YVO4, respectively, are formed which are stable up to 1000°C. 相似文献