[en] We have prepared the large-scaled gallium oxide nanowire arrays on sapphire substrates using a reaction of a trimethylgallium (TMGa) and oxygen (O₂) mixture. The cross-section of the gallium oxide nanowires had a circular shape with the diameter of about 40-110 nm. Transmission electron microscopy and X-ray diffraction analysis together showed that the nanowires were amorphous phase. Photoluminescence measurements indicated that as-prepared nanowires showed two emission band at 365 and 470 nm

[en] We formulate the helicity amplitudes for multiple bremsstrahlung processes in massless gauge theories in terms of spinor inner-products. In the non-abelian case (QCD) we show that contributions from the diagrams with gluon self-coupling can be decomposed into parts to be included together with QED-like diagrams in gauge-invariant subsets, and the amplitudes of the parts are related to the amplitudes of QED-like diagrams. This enables us to make use of the simplifying power of the helicity amplitude method as far as possible. (orig.)

[en] When nuclear potential wells are connected by an atomic potential well, a new kind of tunneling may happen even if there is no virtual energy level in nuclear potential wells. The necessary condition for this combined resonance tunneling is the resonance in the atomic potential well. Thus, the nuclear reaction may be affected by the action in atomic scale in terms of combined resonance tunneling. The nuclear spectrum data support this idea. (author)

[en] Control Element Drive Mechanism Control System (CEDMCS) plays a decisive role in regulating the reactor power and shutting down the reactor in the trip condition. But, due to the failure of CEDMCS, the operating plants have had many experiences such as unexpected reactor trip or interruption during normal plant operation. To prevent those kinds of problems, it is required to improve control logic. Zero cross detection cards in CEDMCS could be made trouble which cause unexpected reactor trip resulted from fluctuating frequency of input signal coming from from M/G set. Some of the problems have been solved by modifying zero cross detection card circuit, but the other problems, such as output voltage variation resulted from input frequency change. Because current zero-cross detector was designed by analog technology, it was difficult to resolve output voltage variation problem. In this report the zero cross detector was improved to resolve voltage fluctuating problem by using new devices such as digital noise filtering circuit is better than old one. If suggested detector is applied to plant, it is possible to use it under House Load Operation because stable output voltage can be generated by new zero-cross detector. (author). 3 tabs., 21 figs., 10 refs

[en] The Korea Next Generation Reactor (KNGR) man-machine interface(MMI) design adopting digital technologies has been developed. The KNGR MMI consists of CRT-based compact operator workstations, a Large Display Panel (LDP) and others. Many human factors experiments have been performed to evaluate and enhance the KNGR MMI design. For these experiments, training for the use of CRT-based MMI has been performed usually to the operators operating nuclear power plants in conventional control rooms. In this report, test sheets for evaluating operators' skill of using CRT process mimic, the most complex information structure among the design elements of KNGR MMI, and LDP, another important information source for operators, are developed to evaluate rather objectively that such training is suitable for the human factors experiments of KNGR MMI design evaluation. For the CRT process mimic, five sets of test sheets are developed for each reactor operator, turbine operator, and control room supervisor. For the LDP, six sets of test sheets are developed for all of the three operators. This report describes the development process and includes test sheets, performance recording sheet, and test procedures

[en] This project has been performed as cooperative research between KAERI and USNRC. Human factors issues related to soft controls, which is one of key features of advanced HSI, are identified in this project. The issues are analyzed for the evaluation approaches in either experimental or analytical ways. Also, issues requiring additional researches for the evaluation of advanced HSI are identified in the areas of advanced information systems design, computer-based procedure systems, soft controls, human systems interface and plant modernization process, and maintainability of digital systems. The issues are analyzed to discriminate the urgency of researches on it to high, medium, and low levels in consideration of advanced HSI development status in Korea, and some of the issues that can be handled by experimental researches are identified. Additionally, an experimental study is performed to compare operator's performance on human error detection in advanced control rooms vs. in conventional control rooms. It is found that advanced control rooms have several design characteristics hindering operator's error detection performance compared to conventional control rooms

[en] The ground state and its structure for a rotating, harmonically trapped N -boson system with a weak repulsive contact interaction are studied as the angular momentum L increases up to 3N . We show that the ground state is generally a fragmented condensate due to angular momentum conservation. In response to an (arbitrarily weak) asymmetric perturbation of the trap, however, the fragmented ground state can be transformed into a single condensate state. We manifest this intrinsic instability by calculating the conditional probability distributions, which show patterns analogous to the boson density distributions predicted by mean-field theory

[en] The proposed system, the ACTS(Alarm Cause Tracking System), in the 1st and 2nd development period(2001. 7 ∼ 2003. 6), tracks and displays the causes of alarms on-line from computerized logic diagrams. And the system highlights the specific procedures related the causes in the procedure of the alarm. In this period(2003. 7 ∼ 2004. 4), we developed the ACTS for Korea standard nuclear power plant. Also, we computerized control logic diagrams and alarm procedures for the ACTS. A long-term target is to apply the ACTS at the real power plant, and a short-term target is to connect the ACTS with the ITF(Intergrated Test Facility) in KAERI site to develop other applications

[en] Components of Korea Superconducting Tokamak Advanced Research (KSTAR) are irradiated by these neutrons and this results in activation of materials which is related to integrity and contamination of fusion devices. Neutron fluence map for KSTAR is necessary to be developed to ensure safety of the components and evaluate contamination for decommissioning in the future. Therefore, this study aims to develop the neutron flux map for KSTAR by Monte Carlo neutron photon transfer code (MCNP) simulation. In this study, the analysis of neutron flux at the major component of KSTAR was conducted with MCNP simulation, and neutron flux map for KSTAR was drawn using MCNP mesh simulation. KSTAR model was constructed based on the material, geometrical, and source information. The number of TF coils and ports were simplified, and PF coils and minor components were not considered in this model for rapid simulation. Results showed that the neutron flux was higher in order of distance from the plasma, and the energy distribution of the neutrons was different in high energy region at the components. The neutrons primarily decreased at the limiter and vacuum vessel based on the result.

[en] The residual magnetic field exists out of the edge in mass analyzing magnet(fringing effect). Therefore, the trajectories of charged particles are affected by the fringing field. From a study of particle trajectories, it is known that the effective magnetic field boundary is not the mechanical boundary of the magnet but the virtual field boundary determined by ∫h(S)ds=ssub(1) for the fringing field function h(S). In this experiment, the effective field boundary is found to be 1.5cm from the mechanical boundary for the magnet with 1 inch air gap. (Author)