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[en] Monoclinic bismuth vanadate (BiVO4) powders were prepared by a mild hydrothermal method, using an aqueous solution of bismuth nitrate and two different vanadium sources (V2O5 and NaVO3). The characterization of as-prepared BiVO4 was carried out by X-ray diffraction (XRD), Raman spectroscopy, Fourier transform infrared (FTIR) and scanning electron microscopy (SEM). The results revealed that in the present work the temperature of 200 and 140 deg. C are sufficient to prepare phase pure BiVO4 powders from V2O5 and NaVO3, respectively. The BiVO4 sample prepared from V2O5 consists of an agglomeration of small rod-like particles. When BiVO4 was prepared from NaVO3, monoclinic BiVO4 powder with a plate form is obtained
Journal
Materials Science and Engineering. B, Solid-State Materials for Advanced Technology; ISSN 0921-5107; 
; CODEN MSBTEK; v. 104(1-2); p. 36-39
; CODEN MSBTEK; v. 104(1-2); p. 36-39
[en] This work numerically investigates the radiative properties of film-coupled metamaterials made of a two-dimensional metallic concave grating on a continuous metal film separated by an ultrathin dielectric spacer. Spectrally-selective absorption is demonstrated in the visible and near-infrared regime, and underlying mechanisms are elucidated to be either localized magnetic polaritons (MPs) or surface plasmon polaritons (SPPs). The unique behaviors of MPs and SPPs are explained with the help of electromagnetic field distributions at respective resonance frequencies. An inductor–capacitor model is utilized to further confirm the excitation of MP, while dispersion relation is used to understand the behaviors of different SPP modes. Geometric effects of ridge width and grating period on the resonance absorption peaks are discussed. Moreover, directional responses at oblique incidences for different polarization states are studied. Fundamental understanding gained here will facilitate the design of novel metamaterials in energy harvesting and sensing applications. - Highlights: • Selective absorption was numerically realized with film-coupled concave gratings. • Underlying mechanisms were elucidated as magnetic and surface plasmon polaritons. • An inductor–capacitor model was employed to confirm the magnetic polaritons. • Dispersion relation was used to explain the behavior of surface plasmon polariton. • Effects of geometric factors, oblique angle and polarization were also discussed
Journal
Journal of Quantitative Spectroscopy and Radiative Transfer; ISSN 0022-4073; ; CODEN JQSRAE; v. 158; p. 127-135
; CODEN JQSRAE; v. 158; p. 127-135
[en] Hf hydride is proposed to be used as neutron control materials for fast reactors. The electronic, mechanical and thermal properties of its three phases: δ′-HfH1.5, δ-HfH1.75, ε-HfH2, are investigated. Their relative stabilities at 0 K by our calculation are consistent with the explanation of Jahn–Teller mechanism. The mechanical properties like elastic constants are calculated and agree well with the experiments. At finite temperatures, in addition to the direct method for phonon calculation, electronic free energy is also calculated in order to investigate the thermal expansion and bulk moduli of three phases. Hf–H system has an increasing relationship in bulk moduli with respect to the H concentration before about 360 K, after which ε-HfH2 seems to decrease more quickly in the softness of the structure than δ-HfH1.75 as the temperature increases. The relation between heat capacity and Hf and H atoms vibration is discussed
Journal
[en] Nanocomposite Co-C thin films of about 15 nm thick were prepared by pulsed filtered vacuum arc deposition. The films were characterized by X-ray photoelectron spectroscopy, non-Rutherford backscattering spectrometry, X-ray diffraction, and magnetic force microscopy. The as-deposited films were amorphous. After annealing at 350 deg. C for 1 h in vacuum (<10-3 Pa), the films were found to consist of nanocrystalline Co grains encapsulated in carbon. The superparamagnetism of the annealed Co36C64 film was demonstrated by the measurement of DC susceptibility and magnetic hysteresis using a SQUID magnetometer. The superparamagnetic relaxation blocking temperature was marked to be about 12 K by the peak of the zero-field-cooled magnetization under a field of 100 Oe. The magnetic properties of these annealed granular Co-C films transform from superparamagnetism to ferromagnetism when the Co concentration increases
Journal
[en] Microcalorimetric titrations have been performed in acidic aqueous solution at 25 deg. C to calculate the complex stability constants (KS) and thermodynamic parameters (ΔG deg., ΔH deg., and TΔS deg. ) for the stoichiometric 1:1 complexation of lanthanoid(III) nitrates (La-Gd, Tb) with 5,11,17,23-tetrasulfonato-25,26,27,28-tetrakis (hydroxycarbonylmethoxy)calix[4]arene (2) and 5,11,17,23-tetrasulfonato-thiacalix[4]arene (3). Using the present and previous reported data on water-soluble calix[4]arenesulfonates (1) and structurally related analogues 2 and 3, the complexation behavior is discussed comparatively from the thermodynamic point of view. Possessing four carboxyls at the lower rim of parent calix[4]arenesulfonate (1), the derivative 2 displays the enhanced binding abilities for Sm3+. As compared with 1 and 2, p-sulfonatothiacalix[4]arene (3) gives not only the lower binding constants for all of lanthanoid(III) ions but also lower cations selectivity. Thermodynamically, the resulting complexes of lanthanoid(III) ions with 1 and its derivatives 2 and 3 is absolutely entropy-driven in aqueous solution, typically showing larger positive entropy changes. These larger positive entropy changes (TΔS deg.) and somewhat smaller positive enthalpy changes (ΔH deg.) are directly contributed to the complexes stability as a compensative consequence
Journal
[en] Amorphous CoxC1-x thin films, with x in the range of 60-75% in atomic percentage, have been prepared by pulsed filtered vacuum arc deposition. The structures of the films were characterized by transmission electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. The in-plane magnetic hysteresis loops were measured by a superconducting quantum interference device magnetometer at room temperature. The electrical transport properties were measured by the four-probe technique at various temperatures ranging from 20 to 300 K. The films were found to be magnetically soft with coercivities in the range of 2 to 12 Oe, resistivities in the range of 130 to 300 μΩ cm, and magnetic saturation flux densities in the range of 6 to 13 kG. The films also showed good thermal stability in their structural, electrical and magnetic properties upon annealing up to 200 deg. C in a vacuum furnace
Journal
[en] In the EPR project construction progress, with method of observing schedule system part by part, then as a whole, compare the EPR schedule management methods with CPR1000. Especially focus on EPR nuclear island design schedule construction method-First construction schedules divided, then establish links with different project schedule as a whole. And compare EPR NI design schedule with CPR1000 in EPS, WBS and so on, at the same time also explaining the important function of interface project which between upstream schedule and downstream schedule. Present civil work, system and layout design schedule construction ways of nuclear island, and discuss about the time arrangement of these milestones, to achieve the target of experience feed back. (authors)
Source
Chinese Nuclear Society, Beijing (China); 460 p; ISBN 978-7-5022-5040-9; ; Nov 2010; p. 346-350; '09: academic annual meeting of China Nuclear Society; Beijing (China); 18-20 Nov 2009; 1 fig., 1 tab., 2 refs.
; Nov 2010; p. 346-350; '09: academic annual meeting of China Nuclear Society; Beijing (China); 18-20 Nov 2009; 1 fig., 1 tab., 2 refs.
[en] The saturated flow boiling heat transfer of water (H2O, R718) is encountered in many applications such as compact heat exchangers and electronic cooling, for which an accurate correlation of evaporative heat transfer coefficients is necessary. A number of correlations for two-phase flow boiling heat transfer coefficients were proposed. However, their prediction accuracies for H2O are not satisfactory. This work compiles an H2O database of 1055 experimental data points from micro/mini-channels from nine independent studies, evaluates 41 existing correlations to provide a clue for developing a better correlation of saturated flow boiling heat transfer coefficients for H2O, and then proposes a new one. The new correlation incorporates a newly proposed dimensionless number and makes great progress in prediction accuracy. It has a mean absolute deviation of 10.1%, predicting 81.9% of the entire database within ±15% and 91.2% within ±20%, far better than the best existing one. Besides, it also works well for several other working fluids, such as R22, R134a, R410A and NH3 (ammonia, R717), being the best for R22, R410A and NH3 so far. - Highlights: • Compiles a database of 1055 data points of H2O flow boiling heat transfer. • Evaluates 41 correlations of flow boiling heat transfer coefficient. • Generalize approach for developing experiment-based correlation. • Propose a correlation of H2O flow boiling heat transfer in small channels. • The new correlation has a mean absolute deviation of 10.1% for the database
Journal
[en] A mild hydrothermal method has been adopted to prepare La0.5Sr0.5MnO3 and La0.5Ba0.5MnO3, which is of interest for a number of possible applications. The results from X-ray diffraction (XRD) indicate that in the present work the temperature of 200 and 240 deg. C are sufficient to prepare phase pure La0.5Sr0.5MnO3 and La0.5Ba0.5MnO3 crystals. At 200 deg. C, La0.5Sr0.5MnO3 nanowires are obtained. The average width and length of the nanowires are 40 nm and 4 μm, respectively. At 240 deg. C, La0.5Ba0.5MnO3 powders obtained have a cubic structure with the average size of 3-5 μm
Journal
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