[en] The derivative spectra of complexes of rare earths with Tiron (disodium 1, 2-dihydroxybenzene-2, 5-disulphonate) have been studied. In 0.05∼0.3 mol.dm^-3 sodium hydroxide solution, Pu, Nd, Sm, Dy, Ho, Er and Tm form colorless complexes with Tiron which show characteristic aborption bands in visible and ultraviolet range, due to f-f transition. The sensitivity, as well as the selectivity, of the third and the fourth order derivative spectra of the complexes increases considerably in comparison with the normal spectrophotometry in the same system. Non-rare earth cations and anions do not interfere with determination of the rare earths when the concentration of Tiron is in excess. Few rare earths interfere with each other slightly except neodymium, which interferes with dysprosium seriously. But the effects can be corrected quantitatively by using correction coefficients. The accuracy of the present method has been tested with two kinds of synthetic samples (one consists mainly of light rare earths and the another heavy rare earths). Generally, relative errors and coefficients of variation of analytical results are smaller than 3% and 5% respectively. The results for the mixture of fifteen rare earths obtained by this method agree well with those of X-ray fluorescence and extraction chromatography. The coefficients of variation of most rare earths are smaller than 5%. The present method can be used to determine Pr, Nd, Sm, Dy, Ho, Er and Tm directly in mixture of rare earths with satisfactory results

[en] A new method has been developed for rapid determination of small amounts of Nd, Ho, Er and Tm in a mixture of rare earths by the third derivative spectrophotometry with thenoytrifluoroacetone. The accuracy has been tested by synthetic samples with satisfactory results. This method is more accurate, simple and rapid. No separation is required. The results obtained are identical with those of X-ray fluorescence spectroscopy and extraction-chromatographic method. (Author)

[en] Highlights: • First principles is employed to study the structure of K₂B₁₂H₁₂. • Predict the thermodynamic reversible hydrogen reactions in the KBH₄/M(M = Li, Na, Ca)(BH₄)_n(n = 1,2) system. • Predict two new hydrogen storage reactions involving KBH₄ for on-board hydrogen storage. - Abstract: Potassium borohydrides [KBH₄] is an attractive candidate for on-board storage because it contains high densities of hydrogen by weight and volume. Using a set of recently developed theoretical first-principles methods, we predict hydrogen storage reactions in the K-M(Li, Na, Ca)-B-H system. Hydrogen release from KBH₄ is predicted to proceed via intermediate K₂B₁₂H₁₂ phase. In the present study, we predict two new hydrogen storage reactions that are some of the most attractive among the presently known ones. They are predicted to have thermodynamics for hydrogen release within the target window for on-board storage being actively considered for hydrogen storage applications

[en] Highlights: •Fabrication of planar waveguides in CSBN25 crystal by MeV C ion implantation at low fluence. •The extraordinary index has a small positive change in the surface region after the implantation. •The relation between index profile parameters and C⁺ ion energy loss were considered. -- Abstract: Planar optical waveguides were fabricated in (Ca_0.28Ba_0.72)_0.25(Sr_0.6Ba_0.4)_0.75Nb₂O₆ (CSBN25) crystal by 6.0-MeV C⁺ ion implantation with fluences of 2, 4 and 6 × 10¹⁴ ions/cm² at room temperature. The mode parameters, refractive indices profiles are measured and the refractive indices behavior in the waveguide region is discussed. The shape of nuclear energy loss distribution of the C⁺ implantation was similar to those of the waveguide refractive index profiles, which means an inherent relationship between the waveguide formation and the energetic energy deposition. The extraordinary refractive index has a small positive change in the surface region after the implantation

[en] Heavy water can be used as moderator material of a nuclear reactor. The concentration of heavy water affects the safety and property of the reactor directly. This work was carried out in order to research the type of relationship curve between heavy water concentration and absorbance. Based on Lambert-Beer's law, the formulas between heavy water concentration and absorbance were theoretically derived respectively when the absorption peak of a certain kind of water molecules in liquid heavy water overlaps with the absorption peak of zero to two other kinds of water molecules. The types of relationship curve between heavy water concentration and absorbance were discussed in different cases. The absorption spectra of heavy water in the concentration range from 0.015% to 99.98% (mol vs mol) were recorded by fourier transform infrared spectrometer and the types of relationship curve were analyzed. It showed that the theory tallied with the practice. The type of relationship curve between heavy water concentration and absorbance was quadratic curved in a wide concentration range and linear when the concentration range was narrow. In special cases, the absorbance was fixed or the type of relationship curve was linear. (authors)

[en] High concentrate heavy water was used as moderator or coolant in a reactor, and its concentration directly effects the safety and performance of the reactor. The samples were generally taken from the process system manually and then analyzed with infrared spectrophotometry in the laboratory off-line. This study was carried out to quantify high concentrate heavy water of process system accurately, quickly and safely. In this work, infrared absorption spectrum of different concentrations of standard heavy water were gotten on the Fourier infra-red spectrometer off-line, with the single beam spectrum of empty optical path as the background spectrum. A working curve between the absorbance at the wavenumber of 3410 cm^-1 and concentrations of heavy water was established with linear function. On this basis, the program of high concentration heavy water on-line measurement was designed. The measurement method is accurate, rapid, non-destructive and without irradiation. For 99.85% heavy water concentration, the relative standard deviation was better than 0.01%. When the deter-mined range of heavy water was 99.06%-99.98%, the linear correlation coefficient R² was 0.9999. This method could also be extended to determine heavy water with other concentration ranges.(authors)

[en] In the current study, the two-dimensional mold model was applied to investigate the influence of different casting parameters on the initial solidification at the meniscus of the continuous casting mold. The profile of the meniscus and the slag rim, and the heat flux on the hot face of the copper plate, were compared with different locations of the mold and different casting parameters. The depth of the oscillation marks and solidified meniscus through simulation was measured with different casting parameters. With the mold oscillating downward from the peak to the valley, the maximum heat flux on the hot face of the copper plate near the meniscus increased from 4.3 to 5.5 MW/m², the thickness of the slag rim decreased from 4.7 to 4.2 mm, and the height of the curved meniscus also decreased. With the increase of casting speed from 1.2 to 1.45 m/min, the maximum speed of the upper backflow increased from 0.6 to 0.8 m/s, and the lowest location of the meniscus at approximately 310 mm from the copper plate decreased from 22 to 12 mm below the meniscus near the nozzle, where the slag entrapment easily occurred. With the increase of the casting speed, casting superheat, and oscillation frequency, and the decrease of the water flow rate in the mold and oscillation amplitude, the thickness of the slag rim decreased. With the increase of casting speed and superheat, and the decrease of the water flow rate in the mold, oscillation frequency, and oscillation amplitude, the depth of the solidified meniscus decreased. The regression equation was fitted to estimate the depth of hooks at the subsurface of slabs.

[en] The effect of heat treatment on the transformation of inclusions in linepipe steels was investigated experimentally and theoretically. During heat treatment, CaO-Al₂O₃ type of inclusions in steels before heating transformed into Al₂O₃-CaS type, and in the form of CaS-Al₂O₃-MgO eventually with CaS formed on the surface of Al₂O₃-MgO phase, depending on the heating temperature, heating time, size of inclusions, and components such as T.Ca and T.O in steels. The transformation details were revealed by thermodynamic calculations and kinetics analysis; what is more, the coefficients k_inc of each composition in inclusions such as Al₂O₃, MgO, CaO, and CaS at 1473 K (1200 °C) were calculated, respectively. The theoretical results in this paper are in good agreement with the experimental observations.

[en] To be able to deduce water holdup from the mixture conductivity measured by conductance sensors in water continuous oil–gas–water three-phase flow, the water conductivity must be known in advance. As water conductivity depends on water salinity and temperature, variation in water salinity or temperature changes the water conductivity, which seriously affects water holdup measurement. In this study, we propose a novel online technique to detect the conductivity of water in vertical upward oil–gas–water flows in 20 mm inner diameter pipe via the conductance method. A water conductivity sensor (WCS) is designed and the geometry of the electrodes in its water trapping cavity is optimized using finite element methodology. After this, the relationship between sensor response and water conductivity is investigated. WCS performance is experimentally evaluated and the results show that the WCS can effectively detect the water conductivity in a three-phase mixture online. By correcting the water conductivity in the expression for the normalized conductivity of a rotating electric field conductance sensor, water salinity and temperature independent water holdup measurement can be realized. Based on the relationship between the calculated water holdup and water cut, the superficial velocity of water is accurately predicted despite differences in water conductivity. (paper)

[en] The turbulent flow around bubbles is simulated for the fixed turbulent kinetic energy. Inclusion motion through the flow field is studied by considering the stochastic effect of turbulence to calculate the capture probability of inclusions with different sizes to a fixed-size individual bubble according to the redefinition. Using the cubic spline interpolation, the capture probability is predicted as functions of the bubble size, inclusion size and turbulent kinetic energy.