Advanced Materials Research Vols. 781-784

Abstract: To explore the effect of logfO₂(g), pH, uranium concentration, phosphate concentration and NaCl concentration on the predominance diagrams of dissolved uranium species and formation of solid phases containing uranium in the U-PO₄^3--NaCl-H₂O system at 25 °Cand PCO₂ =10^-3.5 MPa, the thermodynamic model of this system was constructed. Based on the results of calculation, the logfO₂(g)-pH diagrams were drawn. It can be found that: 1) the formation of uraninite needed enough reductive condition (about logfO₂(g) < -50 ), while the formation of Na-Autunite needed the strict pH range (5<pH<8) in oxidative condition. 2)The addition of phosphate concentration could promote the formation of Na-Autunite, and inhibit the formation of U₄O₉(C). 3)The independent increasing of uranium concentration can lead to more kinds of uranium species.4) The variance of NaCl concentration had little impact on the formation of solid phases containing uranium.

Abstract: A quasiclassical trajectory calculation is carried out to investigate the effect of reagent vibrational excitation on product rotational polarization in the reactions Li + DF (v=0-3, j=0) ---> LiF(v', j') + D. It is found that the reagent vibational excitation highly enhanced the product rotational alignment, however, the enhancement is not monotonically increasing with the gradual increase of the vibrational quantum number from v=0 to v=3. The product rotational orientation varies from the negative to positive direction of y axis with the increasing vibrational quantum number from v=0 to v=3.

Abstract: A first quasiclassical trajectory calculation for the reaction H + OCl OH + Cl, HCl + O has been carried out on the ground 1¹A' potential energy surface (PES) at the collision energy of 7.6 kcal/mol. The stereodynamics and product state distributions were focused on computation and analysis. It was found that, for both the OH and HCl products, the product rotational alignment and orientation were very weak. Most of the OH products are at lower vibrational levels. The HCl products dominantly populate in the ground vibrational state v'=0. Inverted rotational state distributions were found in each of the vibrational state for both the OH and HCl products. As a consequence, the title reaction takes place dominantly through an indirect mechanism involving a long-lived complex.

Abstract: A novel hydrogen storage material Mg₂Ni has been studied by the first-principle methods based on plane-wave pseudopotential theory. The corresponding electronic structure of hydrogen storage materials, Mg₂Ni, Mg₁₂Ni₅M₁ (M = Mn and Cu), and their hydride have also been investigated. The enthalpy of hydrogenation reaction is-65.07kJ/mol (H₂), which is in line with the experimental results. The stability of the new hydride alloy increased by substitution with Cu, and a small amount of alternative might be preventing powdering after several cycles. The Mn atom substitutes Ni atom of hydride alloy which would weaken the H-Ni bond, and the temperature of desorption decreased. The results will play an important role in practical application.

Abstract: It is important to find out how to strengthen the interaction between nickel porphyrins and asphaltene in the alkane solvents of the low molecular weight for raising the removal rate of nickel in the solvent deasphalting process. Therefore, the adsorption kinetics, which describes how the nickel etioporphyrins are adsorbed on asphaltene (the vacuum residue of Canadian oil sands bitumen (VTB)) in the n-pentane solvent, are investigated. The results show that a certain amount of nickel porphyrins is absorbed on the asphaltene of VTB, which means there is a certain adsorption between asphaltene and nickel porphyrins. The adsorption rate is affected by the dosage of asphaltene, the concentration of the n-pentane solution containing nickel porphyrins and the temperature. A comparison in the four kinds of kinetic models on the overall adsorption rate shows that adsorption process can be perfectly described by the pseudo second-order equation.

Abstract: Dependent component analysis (DCA), which is an extension of independent component analysis (ICA) for blind source separation (BSS) and requires no assumption on the distributions of the sources, was used to directly estimate source spectral profiles from ultraviolet spectra (UV) of mixtures. By simply assuming that the sources are dependent only through their variances and have temporal correlations, variance DCA was established. The efficiency of DCA for estimation of source UV spectral profiles was qualified by synthetic mixed UV data. It was shown that the estimation efficiency of DCA is better than that of FastICA when the sources are seriously overlapped. Then the DCA was used to directly estimate source spectral profiles from UV data that were measured at different steaming periods during the processing procedure batch for preparation of radix scutellariae. The estimated dependent components (DCs) and their variations of relative concentrations were used to characterize the processing batch. The results show that the estimated DCs are corresponding to sterol and flavonoid compounds, respectively. By inspection of the change trends of the estimated DCs, the endpoint of the processing batch was determined as 55 min, which is more accurate than that it should be located in 30~60 min by traditional sensory analysis. DCA provides an alternative approach for estimation of source spectral profiles from the overlapped spectral signals, and UV-DCA can be used as a novel way for characterization of the traditional Chinese medicines processing procedure.

Abstract: A method is developed to detect estradiol valerate which is based on the phenomenon that estradiol valerate can enhance the resonance light scattering intensity of CdS QD. Cetyl Trimethyl Ammonium Bromide (CTMAB) is added to sensitize this system. Under optimum conditions, the enhanced intensity of the system is in proportion to the concentration of estradiol valerate in the range of 5.0×10^-8 ~ 6.0×10^-7 gmL^-1. The detection limit is 1.2×10^-8 gmL^-1. It has advantages that simple, sensitivity and stable.

Abstract: Coal quality analysis is an important part in the fuel management of power system. The coal calorific value (CCV) is the basis to appraisal of coals heat balance calculation, coal consumption, heat efficiency and improving of heat utilization. There exist many methods on estimation of CCV. Artificial neural networks have many advantages in this area. This paper described the network structure, the mathematical model and the algorithm flow of BP neural network (BPNN) and Elman neural network (ENN) which are both used for the CCV estimation. Results show that both BPNN and ENN can well reflect the non-linear relationship between CCV and other factors of coal quality. And ENN is more accurate to predict CCV, with smaller absolute error.

Abstract: A method for the study of the volatile components in Atractlodesm acrocephala Koidz from different sources with combined chemometrics methods was developed. After the volatile components in Atractlodesm acrocephala Koidz from two different locations were detected by GCMS, the qualitative and quantitative analysis of the volatile components of Atractlodesm acrocephala Koidz from Tiantai was conducted with SFA. Then, the common peak in Atractlodesm acrocephala Koidz sample from Xinan was extracted with orthogonal projection method. Among the identified components, there were 37 components coexisting in the studied samples although the relative content of each component showed difference to some extent. The obtained results can provide useful information for the developing of fingerprint of Atractlodesm acrocephala Koidz. It also can be used to compare the sameness and differences of Atractlodesm acrocephala Koidz from different sources and for quality control of Atractlodesm acrocephala Koidz.