The ultrafine titanium carbonitride particles () below 100nm in mean size were successfully synthesized by Mg-thermal reduction process. The nanostructured sub-stoichiometric titanium carbide () particles were produced by the magnesium reduction at 1123K of gaseous and the heat treatments in vacuum were performed for five hours to remove residual magnesium and magnesium chloride mixed with . And final phase was obtained by nitrification under normal gas at 1373K for 2 hrs. The purity of produced particles was above 99.3% and the oxygen contents below 0.2 wt%. We investigated in particular the effects of the temperatures in vacuum treatment on the particle refinement of final product.

Ultrafine titanium carbide particles were synthesized by the reaction of liquid-magnesium and vaporized TiCl+CCl(x = 1 and 2) solution. Fine titanium carbide particles with about 50 nm were successfully produced by combining Ti and C atoms released by chloride reduction of magnesium, and vacuum was then used to remove the residual phases of MgCl and excess Mg. Small amounts of impurities such as O, Fe, Mg and Cl were detected in the product, but such problem can be solved by more precise process control. The lattice parameter of the product was 0.43267 nm, near the standard value. With respect to the reaction kinetics, the activation energy for the reactions of TiCl+CCland Mg was found to 69 kJ/mole, which was about half value against the use of TiCl+CCl, and such higher reactivity of the former contributed to increase the stoichiometry until the level of TiC and decrease the free carbon content below 0.3 wt.%.

n-Octyldimethylbenzylammonium chloride, dodecyldimethylbenzylammonium chloride, and octadecyldimethylbenzylammonium chloride were synthesized to be used as the accelerating weight loss agent. These synthesized compounds were used for the weight loss treatment of PET textile with sodium hydroxide. From the treatments, it was found that the lower carbon number of high alkyl group existed in quaternary ammonium salts, the better effect of weight loss was acquired. The proper concentration of accelerating weight loss agent was 8~10g/l, the proper treatment time was 60~90 minutes, the proper treating bath ratio was 1 : 50. It is proved that n-octyldimethylbenzylammonium chloride and dodecyldimethylbenzylammonium chloride are good accelerating weight loss agent.

해상 강교량은 특성상 혹독한 부식환경에 가설되어 있으며 장기간 공용중인 강구조물의 경우 염분에 의한 부식손상과 도막노화로 구조물의 정기적인 보수도장이 필요하다. 또한 부식손상과 도막노화, 온습도, 비래염분등의 다양한 원인에 의하여 발생된다. 하지만 도막표면에 부착되는 염분량은 비래염분량의 영향뿐만 아니라 구조형식 및 강우 유무에 따라 변화하게 되며, 해상강교량에서 12개월간 도막표면에 부착되는 염분량을 측정 하였다. 그리고 구조형식에 따라 누적 부착염분량의 차이로 도막노화 및 부식손상의 속도가 다르게 나타날 수 있으며, 보수도장을 위한 의사결정 과장에 기초자료로 활용할 수 있다.

In this research, airborne chlorides of sea bridges in terms of height were measured every month in the West and South coast for 1 year. The results showed that the decreasing tendency of airborne chlorides to height strongly depends on the maximum amount of airborne chlorides of the target area.

In this study, airborne chlorides by height of sea-crossing bridges in West and South seashore were discussed. As the results during spring and summer, the higher altitude, the less airborne chlorides was detected. However, the closer height to the traffic road, the more abundant airborne chlorides were showed.

There increasing demand for technologies that are capable of producing heat and electric energy by burning fuels such as solid refuse fuel (SRF) and biomass to mitigate the effects of greenhouse gas emissions from fossil fuels and global warming in the field of thermal power generation. In particular, conversion of SRF into energy (Waste to Energy) is the promising technology with high economic and social benefits. The high temperature corrosion of the heat exchange tube is the most important factor that affects the economic deterioration of a circulating fluidized bed boiler using solid refuse fuel, due to operating time decrease and the periodic shutdown during plant operation. The purpose of this study was to examine the high temperature corrosion characteristics of boiler superheater tubes. The change of corrosion characteristics according to the temperature and alkali chloride salt can be investigated by analyzing the morphology of the surface and the microstructure of specimen cross-section and examining the changes in the physical and chemical properties. The degree of corrosion increased as the temperature increased and the weight of the alkali chloride specimen deposit decreased due to the volatilization of the metal chloride compound above 700°C. Deposits of KCl were found to accelerate corrosion by destroying the oxide layer and forming potassium compounds.

The airborne chlorides environment by de-icing salts of the Suam road tunnel in motorway were examined. It was found that higher airborne chlorides were detected inside road tunnel than outside. Therefore, there is a need to appreciate that RC structures inside tunnel might be exposed to salt attack environment.

The airborne chlorides environment by de-icing salts of the Suam road tunnel in motorway were examined. It was found that higher airborne chlorides were detected inside road tunnel than outside. Therefore, there is a need to appreciate that RC structures inside tunnel might be exposed to salt attack environment

The airborne chlorides environment by de-icing salts of retaioning wall in motorway were examined. It was found that in the retaining wall, height of 14m, the airborne chlorides tend to be decreased by height ranged between 81.0-73.8%.

Nitrate in edible vegetables is converted to nitrite by nitrate reductase(NR) and/or bacteria in intestines. Nitrite and amino, in the intestine of some animals and human, bind to form nitrosamine, which is toxic and known as carcinogen. This study was carried out to examine the effect of added chlorides and their concentrations on growth, yield and nitrate content in leaf lettuce plants in hydroponics. Seeds of lettuce cv, "Samsunjokchukmyon" were planted on April 29, and seedlings were planted on June 2, and were cultured until July 5 in 1998. KCI and CaCl₂ were used as chloride source and their concentrations were 1, 2 and 4 me/L, respectively, in the lettuce standard nutrient solution for National Horticultural Research Institute(NHRI). Completely randomized design with 3 replications was used. Nitrate content and NR activity were measured 2 and 5 weeks after planting(WAP). The obtained results were summarized as the follows : Leaf weight per plant was difference from harvest dates and treatments, but total leaf weight was not significantly different among treatments. Number of leaves was higher in KCI 2 me/L, CaCl₂1 me/L and control at 2 WAP than the others, and was higher in KCI 1 me/L, and control at 3 WAP than others, and was higher in control at 5 WAP. Total number of harvested leaves was the highest in control with 14, which followed by KCI 2 me/L and CaCl₂1 me/L. Nitrate content was decreased by addition of chloride in nutrient solution. Nitrate content in the 3rd and 9th leaves was significantly decreased. NR activity was higher in control and CaCl₂ addition treatments, while KCI addition treatments reduced NR activity. However, no direct relationship with nitrate was observed. Growth characteristics such leaf length and leaf width were not significantly influenced by chloride addition.

Gernerally, it is difficult to predict water quality in a tidal river, because tidal flows make the transport phenomena more complicated. The purpose of this study is to clarify long-term mass transport in a tidal river through suggestion of simulation model. A simulation model based on a Lagrangian coordinate system, which has the advantage reducing numerical dispersion, was used to calculate changes in concentration of chlorides. Several field surveys were conducted to verify calculated results. Concludingly, long-term behavior of mas transport in a tidal river can be represented using the model.

Laboratory batch experiments were conducted,using suspended solids and sediments taken from a tidal section of the Rokkaku river,to study the effect of salinity on nitrification and to estimate kinetic parameters of it. Experimental results indicated much more inhibitation of NO_2-N oxidation by chlorides than that of NH_4-N oxidtion. Nitrifying bacteria in sediments were less sensitive to chlorides than those in SS. The change of nitrogen concentration with time was clearly explained with the Monod growth model and the kinetic parameter, were obtained by the curve fitting method.