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[en] The chemical vapor condensation (CVC) process was applied to produce nanosized tungsten carbide powders. Characteristics of the synthesized powders with variations in the CVC parameters were studied. Loosely agglomerated WC_1-x powders could be obtained. The size of the CVCed powders decreased with increasing CVC reaction temperature

[en] Nanocavities created in Ge(111) by 5 keV Xe ion irradiation are characterized by ex situ transmission electron microscopy (TEM). Nanocavities with average diameter of 10 nm are observed at 500 deg. C, while nanocavities with average diameter of 2.9 nm are observed at 400 deg. C. The nanocavities grow beyond equilibrium size at 500 deg. C mainly due to absorption of vacancies produced during 5 keV Xe ion irradiation. The sink strengths of the nanocavities and the Ge surface for absorption of interstitials and vacancies are examined to elucidate the growth of the nanocavities in the absence of apparent biased sinks such as dislocations

[en] Electron beam decomposition of volatile organic compounds (VOCs) was studied in order to obtain information for developing effective treatment method of off-gases from industries. We have examined the combination of electron beam and catalyst honeycomb which is either 1% platinum based or ceramic honeycomb- based aluminum oxide, using a hybrid reactor in order to improve removal efficiency and CO₂ formation; and to suppress undesirable by-product formation e.g. O₃, aerosol, H_xC_y., and tar. The experiments were conducted using a pilot-scale treatment system (maximum capacity; 1800 N m³/h) that fitted the field size to scale up from the traditional laboratory scale system for VOC removal with electron beam irradiation. Toluene was selected as a typical VOC that was irradiated to investigate product formation, effect of ceramic and catalyst, and factors effecting overall efficiency of degradation. Styrene was selected as the most odorous compound among the VOCs of interest. It was found that VOCs could be destroyed more effectively using a hybrid system with catalyst bed than with electron beam irradiation only

[en] We fabricated contact electrodes in Si for nanoelectronic device fabrication using 40 keV As ion implantation. Complete amorphization of the Si surface with contact electrodes using 400 eV Ar ion irradiation at room temperature followed by annealing at 700 deg. C produced Si surface with negligible SiC crystallites suitable for ultrahigh vacuum scanning tunneling microscope nanolithography. We could locate the implanted and unimplanted regions on Si and fabricate Si dangling bond wires between two contact electrodes, which is the first step for the fabrication of nanoelectronic devices in Si using UHV STM nanolithography

[en] The effect of dietary vitamin A and NO2 exposure on the hamster lung was evaluated by histopathology, electron microscopy, and thymidine uptake studies. Hamsters were maintained on deficient (0 micrograms), adequate (100 micrograms), and high (200 micrograms) dose levels of vitamin A while being exposed repeatedly to 10 ppm of NO2 for 5 hours once a week over an 8-week period. Hamsters of the deficient group exhibited clinical and morphologic changes characteristic of vitamin A deficiency. Animals maintained on adequate and high dose levels of vitamin A were not affected by vitamin A deficiency. Hypertrophy and hyperplasia of the epithelial cells of the terminal bronchiolar alveolar region of lungs of adequately and highly dosed animals were greater than those observed in the deficient animals, when NO2 exposure was given. However, the extent of the lesions observed in all three groups was less than that seen in normal hamsters given a single, 5-hour NO2 exposure. Ultrastructural changes observed in vitamin A-deficient hamsters exposed to NO2 were hypertrophy and hyperplasia of bronchiolar epithelial cells, diffuse loss of cilia, membrane damage, and mitochondrial damage manifested by calcium deposition. Tritiated thymidine uptake studies of lungs of animals exposed repeatedly revealed a rather erratic cell renewal pattern following NO2 exposure in comparison to the group of animals exposed singly

[en] A brief description for the basic principle of accelerator mass spectrometry is given followed by an introduction of Seoul National University ¹⁴C-AMS system. Some results of our recent measurements are also presented

[en] Pipelines have the highest capacity and are the safest and the least environmentally disruptive means for gas or oil transmission. Recently, failures due to corrosion defects have become of major concern in maintaining pipeline integrity. A number of solutions have been developed for the assessment of remaining strength of corroded pipelines. However, these solutions are known to be dependent on material properties and pipeline geometries. In this paper, a fitness-for-purpose (FFP) type limit load solution for corroded gas pipelines made of X65 steel is proposed. For this purpose, a series of burst tests with various types of machined pits are performed. Finite element simulations are carried out to derive an appropriate failure criterion. Then, further, extensive finite element analyses are performed to obtain the FFP type limit load solution for corroded X65 gas pipelines as a function of defect depth, length and pipeline geometry

[en] Short communication

[en] A cross section of (12.9+-2.6) nb for the reaction ₂H (₄He, ₆li) at Esub(Lab)=6MeV has been measured. The method consisted of bombarding a ₂H target with a ₄He beam and observing the ₆Li recoils at 0deg through a magnet spectrometer. The result establishes the intrinsic background of direct capture origin for the resonance capture cross section measurement of the 3.562 MeV state of ₆Li. (Author)