[en] The combination of the two types of mode conversion when the lower-hybrid turning point is in the vicinity of a cyclotron harmonic requires a sixth-order equation with a quadratic coefficient, for which the usual technique utilizing the Laplace transform has no advantage since the transformed equation is second order and the general solution is not available. Some numerical methods are applied without success. Another type of six-order equation, which has only linear coefficients and represents the three-wave problem marginally, is solved analytically without including the absorption term. Applying the results of this analysis, it is shown that the direct-mode coupling to the ion-Bernstein wave from the incident lower-hybrid wave takes place effectively only when the lower-hybrid turning point is very close to the harmonic resonance such that the distance between their respective turning points is similar in magnitude to the common wave length of the coupling. Finally, the damping and the absorption of the wave are compared for the unmagnetized dispersion relation, the full magnetized dispersion relation, and the mode-conversion analysis as the wave propagates in a magnetically confined plasma with slab geometry

[en] 

Summary

A robust scheme of moiré interferometry for real-time observation of thermal deformations was developed. It was implemented with a convection-type heating/cooling environmental chamber, which produced rapid temperature control. Vibrations caused by the environmental chamber were circumvented by rigid links that connected the specimen to the moiré interferometer rather than supporting the specimen by the chamber. The result was exceptionally stable fringes. The system was utilized to document temperature-dependent behavior of a PBGA package assembly.

[en] The problem of ion cyclotron harmonic absorption for a lower hybrid wave is shown to be a mode conversion problem. A new form of the dispersion relation is developed and then expanded to get a differential equation identical to that for the second harmonic problem. The validity of this model is restricted to the region far from the lower hybrid resonance layer. It is shown that mode couplings occur among the incident cold wave and two other waves, and the tunneling factor becomes singular there

[en] The existing heat transfer model through the sparger was examined and compared against the experimental data for the reactor drain tank using MELCOR. The amount of steam condensed under water was well agreed each other. Furthermore, the sparger heat transfer module was applied to APR1400. The hydrogen concentration as well as heat transfer behavior in IRWST during the station blackout sequence was examined with this model

[en] DLC (Diamond-like carbon) thin film-deposited polycarbonate specimens were irradiated by high level gamma-ray and made observation of their irradiation effects. In order to do that, diamond-like carbon thin films were deposited on polycarbonate specimens by plasma-enhanced chemical vapor deposition, and then those specimens were irradiated in the high level irradiation facility in KAERI at the same dose rate of 10⁶ rad. Relative concentration of free radicals generated during irradiation of the DLC-deposited and undeposited specimens was determined by the analysis of EPR (electron paramagnetic resonance) spectrum at the elapsed time of 4 hours and 2 months after irradiation of those specimens. As a result of the analysis, it was found that the radical concentration in the DLC-undeposited specimen at the elapsed time of 2 months reduced rapidly in 4 % compared with that at the elapsed time of 4 hours, whereas the concentration in the DLC-deposited specimens decreased slowly in the vicinity of 60 %. Consequently, DLC thin film-deposited polycarbonate specimens resulted in the increase of radiation-oxidation resistance

[en] Purpose: This study investigates the validity of the interval method to determine the anisotropy factors of high dose rate (HDR) ¹⁹²Ir sources. Methods and Materials: A calculation method, which is one of the various numerical implementations of the Sievert integral and known as the interval method, is applied to determine the anisotropy factors of a HDR ¹⁹²Ir source. Calculated results from r = 1 cm to 10 cm are compared to published data. Results: The comparison shows that the error resulting from the interval method increases from 1.3 to 28.1% as the radial distance increases from r = 1 cm to 10 cm and is significantly smaller than that previously reported. Conclusions: The interval method might be considered as a method that provides a very rough estimate of the anisotropy of HDR ¹⁹²Ir sources whenever no conclusive anisotropy data is available

[en] The thickness dependence of interface layers in FeCo-Si multilayers on sputtering voltage, argon pressure and substrate bias potential was examined. The multilayers were characterised by in situ kinetic ellipsometry, X-ray reflection, X-ray diffraction, polarized neutron reflection and atomic force microscopy. A minimum thickness for the sum of both interface layers per period between 23 A and 24 A was found for different combinations of production parameter values. For an argon pressure of 1.3x10^-3 mbar the minimum interface thickness was found at a sputtering voltage of 708 V, and for an argon pressure of 2.3x10^-3 mbar at 880 V. These values were determined for a floating substrate potential of approximately +60 V relative to ground. Applying a substrate bias potential of -70 V the minimum interface thickness occurred for a sputtering voltage of 880 V at an argon pressure of 1.3x10^-3 mbar. This study confirmed the results of the former empirical optimisation. By revealing the existence of several sets of optimum parameters it opens up a further parameter to adjust other properties like stress. The interface layer on top of the FeCo layer is 16% thicker than the one on top of the Si layer due to the larger roughness of the FeCo layers

[en] In situ fast kinetic ellipsometry, X-ray and polarized neutron scattering are used to investigate the growth of sputtered Fe₈₉Co₁₁-Si multilayers with atomic resolution and to determine interface thickness and composition. The values of these properties depend on the sputtering parameters. Under the conditions of minimal thickness of the interface layers we find on top of the silicon layer 15 A (Fe₈₉Co₁₁)_0.5Si_0.5 and on top of the iron cobalt layer 19 A (Fe₈₉Co₁₁)_0.67Si_0.33. During the growth of the iron cobalt layer a phase transition occurs. After the formation of the interface layer on top of the silicon layer the iron cobalt alloy starts to grow in an amorphous phase until a thickness of 25 A is reached. Then it crystallizes down to the interface layer whereby it shrinks to 18.5 A, the atomic density changes nearly proportionally to the imaginary part of the index of refraction. As will be shown, the growth of the layers and the formation of the interface layers can be followed on an atomic scale

[en] A tritium transport model called BETTY has been developed to describe and predict the kinetics of tritium transport in irradiated beryllium in fusion blanket applications. Some USA SIBELIUS experimental data were released and provided useful input data for tritium transport models and code development. An analysis of these USA SIBELIUS experimental data was performed in this paper. A comparison of the tritium kinetics results predicted by the model with those from the experiments shows reasonable agreements. In addition, a parametric sensitivity analysis for the variance of surface activation energies and diffusion coefficient is performed and the minimal effects are observed based on the modeling results

[en] It has been shown that propagation of lower hybrid rays sometimes involves cases where three types of waves are coupled through linear mode conversion in the same region of space, namely the cold lower hybrid wave, the warm lower hybrid wave, and an ion Bernstein mode. This three wave mode conversion problem is analyzed in terms of a sixth order differential equation which describes coupling between all branches, and analytic coupling coefficients are found for the case without the local absorption term. The formal solution of this equation shows that a non-trivial amount of the incident cold wave energy goes into an ion Bernstein mode, which is then absorbed by electrons via Landau damping, rather than converting into the warm branch totally, when they are closely coupled in space