[en] Phase-space formulation based on the Wigner distribution has been presented for analyzing phase-contrast image formation. Based on the statistical nature and affine canonical covariance of Wigner distributions in the phase space, we show that the partial coherence effects of incident x-ray wave field on image intensity are simply accounted for by a multiplication factor, which is the reduced complex degree of coherence of the incident x-ray wave field. We show especially that with the undulator sources one cannot obtain the phase-contrast intensity by summing over the contributions from all electron positions, since the van Cittert-Zernike theorem fails in general for undulators. We derive a comprehensive formula that quantifies the effects of partial spatial coherence, polychromatic spectrum, body attenuation, imaging-detector resolution, and radiation dose on phase-contrast visibility in clinical imaging. The results of our computer modeling and simulations show how the formula can provide design guidelines and optimal parameters for clinical x-ray phase-contrast imaging systems

[en] DBN-Arsenazo is a new chromogenic reagent which forms a binary purple complex with thorium instantaneously in 0.5-1.2 mol^-1 HCl, λ_max = 630 nm, ε_630nm = 1.11 x 10⁵ L mol^-1.cm^-1. Beer's law is obeyed for 0-0.8 μg Th/ml. The complex is stable, not affected by the difference in the temperatures. The interference of heavy rare earch (III) and large amount of uranium (IV) can be effectively eliminated by adding adequate oxalic acid and tartaric acid solution. This method gives high sensitivity and excellent selectively. For determination of n·10^-3% thorium in ore, relative standard deviation is 6.16%

[en] Generalizations of the *-product (e.g., n-ary *_n operations) appear in various places in the discussion of noncommutative gauge theories. These include the one-loop effective action of noncommutative gauge theories, the couplings between massless closed and open string modes, and the Seiberg-Witten map between the ordinary and noncommutative Yang-Mills fields. We propose that the natural way to understand the *_n operations is through the expansion of an open Wilson line. We establish the connection between an open Wilson line and the *_n operations and use it to (I) write down a gauge invariant effective action for the one-loop F⁴ terms in the noncommutative N=4 SYM theory; (II) find the gauge invariant couplings between the noncommutative SYM modes and the massless closed string modes in flat space; (III) propose a closed form for the Seiberg-Witten map in the U(1) case

[en] An iterative phase retrieval algorithm was previously investigated for in-line x-ray phase imaging. Through detailed theoretical analysis and computer simulations, we now discuss the limitations, robustness, and efficiency of the algorithm. The iterative algorithm was proved robust against imaging noise but sensitive to the variations of several system parameters. It is also efficient in terms of calculation time. It was shown that the algorithm can be applied to phase retrieval based on one phase-contrast image and one attenuation image, or two phase-contrast images; in both cases, the two images can be obtained either by one detector in two exposures, or by two detectors in only one exposure as in the dual-detector scheme

[en] We have approximately analyzed the excitation problem of a plasma filled circular waveguide by the TE₀₁ mode of the rectangular waveguide by means of the Fourier transform and the method of the mode expansion. Application of the continuity conditions to the junction of both waveguides leads to the simultaneous equations from which we can determine the reflection coefficients. The convergence of the solution and the reflection characteristic of the incident wave are shown in some numerical examples. (author)

[en] Comparing the device of ITER with ICF, I strongly notice that I have an advice to ITER Driven Plasma Physics. I used to study laser-plasma interaction which relates to a strong spontaneous magnetic field (in axial or in azimuthal direction) and found a new particle acceleration named laser-magnetic resonance acceleration (LMRA). The electron acceleration depends not only on the electromagnetic wave intensity, but also on the ratio between electron Larmor frequency and electromagnetic wave frequency. As the ratio approaches to unity, a clear resonance peak is observed. We point out that strong quasistatic magnetic fields affect electron acceleration dramatically in relativity. We derive an approximate analytical solution of the relativistic electron energy in adiabatic limit, which provides a full understanding of this phenomenon. ITER Driven has strong magnetic fields but no laser beam. If we add a laser beam inside plasma, it will give a quick and efficient ignition process. (author)

[en] Nano-sized Ce-doped YAG phosphor particles were synthesized by a mixed solvothermal method using the stoichiometric amounts of inorganic aluminum and yttrium salts. The formation of YAG:Ce was investigated by means of XRD and TG-DTA. The purified YAG crystalline phases was obtained under moderate synthesis condition (300 deg. C and 10 MPa), this indicated that ethanol replaced part of water as solvent favoring the formation of YAG. TEM images showed that YAG:Ce phosphor particles were basically spherical in shape, well dispersed and a mean grain size about 60 nm. The particle absorbed excitation energy in the range 403-510 nm, and the maximum excitation wavelength was near 470 nm. The crystalline YAG:Ce showed broad emission peaks in the range 480-650 nm and had maximum intensity at 528 nm. The excitation and emission intensity increased with increasing the synthesis temperature from 280 to 300 deg. C, and get the maximum brightness at 300 deg. C

[en] Highlights: • Optical and EPR spectra for CaSGG:Yb"3"+ and LuGG:Yb"3"+ garnets were explained. • The reliability and standardization of fitted CFPs were performed and discussed. • The unavailability of SPM for LuGG:Yb"3"+ garnet was found and analyzed briefly. - Abstract: The crystal-field modeling based on superposition model (SPM) for the orthorhombic Yb"3"+ centers in Ca_3Sc_2Ge_3O_1_2 (CaSGG) and Lu_3Ga_5O_1_2 (LuGG) garnets has been employed to explain their recent experimental optical spectroscopy. Furthermore, the electron paramagnetic resonance (EPR) principal g values for orthorhombic Yb"3"+ centers in LuGG garnet have been interpreted and the predicted g factors for CaSGG:Yb"3"+ garnet are also given. Both calculated optical spectra and EPR g factors for the two Yb"3"+-doped garnets could be regarded as in reasonable agreement with the experimental ones. Two important facts about reliability and standardization of the fitted phenomenological crystal-field parameters (CFPs) have been discussed and the unexpected unavailability of direct parametric modeling by SPM for LuGG:Yb"3"+ garnet is also found and analyzed briefly

[en] The optical spectra and electron paramagnetic resonance (EPR) parameters (g factors and hyperfine structure constants A) for trivalent cerium and ytterbium ions in YF_3 crystal with orthorhombic structure are investigated together by the complete diagonalization (of energy matrix) method (CDM). The obtained results are in reasonable agreement with the experimental ones. More importantly, two magnetically nonequivalent centers in YF_3 crystal observed in EPR experiments are confirmed and ascribed to their specific positions in a unit cell by our calculations based on superposition model (SPM) analysis. Such identification of local sites with different magnetic properties would help us to understand not only the EPR spectra and magnetic susceptibility of other lanthanide ions doped in crystals with the same structure as YF_3 but also the energy transfer scheme between two lanthanide ions occupying such two sites. All results are discussed carefully.

[en] The existence of a large induced magnetic moment in defect single-walled carbon nanotube(SWNT) is predicted using the Green's function method. Specific to this magnetic moment of defect SWNT is its magnitude which is several orders of magnitude larger than that of perfect SWNT. The induced magnetic moment also shows certain remarkable features. Therefore, we suggest that two pair-defect orientations in SWNT can be distinguished in experiment through the direction of the induced magnetic moment at some Specific energy points