[en] We present a new spatial discretization of the discrete-ordinates transport equation in two-dimensional cylindrical (RZ) geometry for arbitrary polygonal meshes. This discretization is a discontinuous finite element method that utilizes the piecewise linear basis functions developed by Stone and Adams. We describe an asymptotic analysis that shows this method to be accurate for many problems in the thick diffusion limit on arbitrary polygons, allowing this method to be applied to radiative transfer problems with these types of meshes. We also present numerical results for multiple problems on quadrilateral grids and compare these results to the well-known bi-linear discontinuous finite element method

[en] The ion channeling technique has been applied to study the stacking defects in heteroepitaxially grown silicon. He ion backscattering experiments were performed on 0.4 μm Si layers grown on sapphire at a beam energy of 1.5 MeV and crystal axes of (100), (110), and (111). A comparison with a single crystal Si wafer developed comparative data which was subsequently used to analyze the depth profile of the density of imperfections. The calculation of dechanneling cross section is based upon the model of 'parallel shift of equipotential contours'. (orig.)

[en] This paper presents a numerical method to solve the electromechanically coupled equations in a brushless DC (BLDC) motor, i.e. Maxwell equation, voltage equation and Newton's equations by introducing the nonlinear finite element analysis and the time stepping method. It also investigates the coupling effect of the eccentric motion of a rotor on the characteristics of the magnetic force and the resulting motion of a BLDC motor by analyzing the free response and Fourier transform of the excitation force and the resulting displacement

[en] The annealing behavior of electroplated copper deposits is reported in this study. The copper deposits were electroplated with a current density of 0.7 A/cm² at 53 deg. C in a sulfuric acid bath containing various concentrations of thiourea. The hardness values of the copper deposits were measured before and after annealing, and the differential scanning calorimetry (DSC) diagrams of the as-electroplated copper deposits were recorded. An improvement of the softening resistance of the copper deposits was observed when the bath contained thiourea ≥3 mg/L. By adding thiourea in the plating bath, smaller grain size of the copper deposits can be achieved. As thiourea content increased ≥3 mg/L, the twin boundary of the copper deposits was significantly increased, and many sulfur-rich particles were deposited along the grain boundaries and a few within the grains of the deposit. These sulfur-rich particles are capable of impeding migration of the grain boundaries and improving the softening resistance of the copper deposits during annealing. The aforementioned microstructures of the copper deposits were examined with transmission electron microscope (TEM) integrated with energy-dispersive X-ray spectrometer (EDX) for chemical composition analysis

[en] We present a new spatial discretization of the discrete-ordinates transport equation in two-dimensional Cartesian (X-Y) geometry for arbitrary polygonal meshes. The discretization is a discontinuous finite element method (DFEM) that utilizes piecewise bi-linear (PWBL) basis functions, which are formally introduced in this paper. We also present a series of numerical results on quadrilateral and polygonal grids and compare these results to a variety of other spatial discretizations that have been shown to be successful on these grid types. Finally, we note that the properties of the PWBL basis functions are such that the leading-order piecewise bi-linear discontinuous finite element (PWBLD) solution will satisfy a reasonably accurate diffusion discretization in the thick diffusion limit, making the PWBLD method a viable candidate for many different classes of transport problems.

[en] The neutron induced nuclear data for Pd-107, I-129 and Cs-135 were calculated and evaluated from 10 keV to 20 MeV for nuclear waste transmutation, using a modular typed empire code package. The energy dependent optical model potential was investigated and applied up to 20 MeV. The optical model, the full feature Hauser-Feshbach model and the multistep direct and multistep compound model were used in the calculation. The direct and semi-direct (DSD) capture model was applied for fast neutron capture in the pre-equilibrium energy region. The theoretically calculated cross sections were compared with the experimental data and the evaluated files. However, experimental data are rare for those nuclei. With the experimental data, the calculated total and capture cross sections were in good agreement. The evaluated cross section results were compiled to ENDF-6 format. The enhanced cross section data will be helpful and more efficient for better transmutation of toxic nuclei. (orig.)

[en] A sensitivity simulation of neutron tomography was performed for the analysis of the spatial distribution of nuclear materials in the HANARO fuel rod. The internal distribution of the nuclear materials in the fuel rod is very important for the increase of the safety and economics of fuel burnup in the reactor. The neutron radiography facility installed at HANARO will be used for the spatial fuel analysis with a real-time image processing system. Monte Carlo simulation was performed to study the feasibility and sensitivity of the HANARO neutron beam for the spatial fuel assay and to find the optimum conditions for neutron detection. From the sensitivity simulation, the location of the nuclear materials in the rod was evident as expected

[en] Neutron data for total and capture cross sections were evaluated on ¹⁶⁰Dy, ¹⁶¹Dy, ¹⁶²Dy, ¹⁶³Dy, and ¹⁶⁴Dy up to 20 MeV. The resolved resonance parameters were adopted from the Mughabghab compilation, but one bound level resonance for each isotope except ¹⁶²Dy was invoked to reproduce the reference thermal cross sections. The average resonance parameters for s-wave neutrons were obtained from the analysis of the statistical behavior of resolved resonance parameters. Recent measurements of the capture cross sections were taken into account in adjusting the average resonance parameters for p- and d-waves. From the first excited energy to 20 MeV, the optical model, Hauser-Feshbach model, and quantum mechanical models were used to produce total, elastic scattering, and capture cross sections. The energy-dependent optical model potential was decided based on the recent experimental data. The calculated cross sections were in good agreement with the experimental data. The present evaluation resulted in improvement over the ENDF/B-VI.7 code

[en] Background X-rays from an Al target bombarded with protons of 0.5, 0.75 and 1.0 MeV and α-particles of 0.5 MeV/amu from the 2.5 MV Van de Graff accelerator were measured with a Si(Li) detector. Production cross section and spectra of continuum X-rays are compared with predictions from the atomic bremsstrahlung(AB) and the secondary electron bremsstrahlung(SEB). Good agreements are obtained. Atomic bremsstrahlung is the most predominant process in this projectile-energy region. The experimental angular distribution of 2.85 - 3.00 keV X-rays for 0.5-MeV proton bombardment is also in good agreement with the calculation of atomic bremsstrahlung. This distribution is symmetric about 90 deg with respect to the incident beam. These results make possible to estimate the sensitivity of the trace-element analysis by PIXE. (author)

[en] Level cross sectioins of /sup 238/U have been deduced from gamma-ray measurements at 125/degree/ following inelastic neutron scattering over an incident energy range of 0.70 to 1.96 MeV. A pulsed source of neutrons was produced via the /sup 3/H(p,n)/sup 3/He reaction. The spectrometer system consisted of a 40-cm/sup 3/ Ge(Li) detector surrounded by a large annular NaI anti-Compton detector, used in conjunction with time-of-flight electronics. Forty-five gamma transitions were observed for twenty-seven levels up to 1516 keV. Finite sample corrections, including neutron attenuation, gamma-ray attenuation and neutron multiple scattering were made for the disk-shaped scatterer. Results are compared to statistical compound-nucleus model calcultions and ENDF. 4 refs