본 연구에서는 PET(PentaEthoxy Tanatalum:Ta(OC2H5)5) 유기금속 화합물 전구체를 사용하여 차세대 초고집적회로 제조시 고유전체 물질로 유망한 Ta2O5 박막을 열화학증착 방법에 의하여 증착하였다. 본 증착실험을 통하여 여러 가지 운속기체, 기판온도, 반응압력 등의 공정변수가 층덮힘에 미치는 영향을 고찰하였으며 Monte Carlo 전산모사 결과와 기판온도 변화에 따른 층덮힘 패턴의 변화에 대한 실험결과를 비교하여 부착계수를 산출하였다. 운송기체로는 N2, Ar, He을 바꿔가며 실험하였으며 He>N2>Artns으로 층덮힘이 양호한 것으로 나타났다. 이는 운송기체의 종류에 따라 운동량 확산도, 열 확산도, 물질 확산도 등의 이동현상 특성값들이 다르기 때문이라 생각된다. 기판온도의 증가는 운송기체의 종류에 관계없이 층덮힘을 악화시켰으며 도랑내부에서의 Knudsen 확산과 표면반응물의 탈착에 비해 표면반응이 보다 지배적인 역할을 담당함을 알 수 있었다. 또한 질소를 운송기체로 사용한 경우에 부착계수의 겉보기 활성화 에너지는 15.9Kcal/mol로 나타났다. 그리고 3Torr 이하에서 반응압력이 증가하는 반응압력이 증가하는 경우에는 물질 확산도의 감소 효과 때문에 층덮힘이 악화되었다. 본 연구결과 3Torr, 350˚C에서 He 운송기체를 이용한 경우가 가장 우수한 층덮힘을 얻을 수 있는 최적 공정 조건임을 알 수 있었다.

With the introduction of the tele-monitoring system (TMS) in South Korea, monitoring of the concentration of pollutants discharged from nationwide water quality TMS attachments is possible. In addition, the Ministry of Environment is implementing a smart sewage system program that combines ICT technology with wastewater treatment plants. Thus, many institutions are adopting the automatic operation technique which uses process operation factors and TMS data of sewage treatment plants. As a part of the preliminary study, a multilayer perceptron (MLP) analysis method was applied to TMS data to identify predictability degree. TMS data were designated as independent variables, and each pollutant was considered as an independent variables. To verify the validity of the prediction, root mean square error analysis was conducted. TMS data from two public sewage treatment plants in Chungnam were used. The values of RMSE in SS, T-N, and COD predictions (excluding T-P) in treatment plant A showed an error range of 10%, and in the case of treatment plant B, all items showed an error exceeding 20%. If the total amount of data used MLP analysis increases, the predictability of MLP analysis is expected to increase further.

Hazardous metals leaching experiment was carried out in accordance with various usage environments for camping cooking utensils distributed in the market. There was a significant difference in the degree of migration for lead, arsenic, cadmium and nickel defending on the solvent and how to use, although they were all appropriate for criteria. In general, the migrated amount of aluminum was increased in acidic condition, and the migrated amount of arsenic was increased in salty condition. Physical scratches increased the overall release of hazardous metals from the portable pots and pans for camping in all solvents. Especially, in 0.5% citric acid solution, cadmium was migrated by physical scratch in stainless steel and hard aluminum pots and pans. The longer the leaching time, the higher the migration of aluminum in acid condition and arsenic in basic condition. From these results, it is desirable to use the cooking utensil for camping without being exposed to strong acidic or basic solution and scratches in order to reduce the migration of hazardous metals from them.

Laboratory investigation was conducted to evaluat the mixing effects on organic removal efficiency to treat low-strength synthetic wastewater using modified anaerobic filter reactor combining anaerobic filter and upflow anaerobic sludge blanket. Using the modified process the low-strength wastewater like municipal sewage could be treated with 85% T-COD removal efficiency at hydraulic retention time of 6 hours. At the constant organic loading of 0.5㎏ COD/㎥-day, the organic removal efficiency and effluent COD concentration are increased as influent COD concentration increased from 125 ㎎/ℓto 500 ㎎/ℓ. Mixing effects on organic removal efficiency are evident and optimum mixing speed is found as 50RPM. Placing the granular studge and media on which slime layer was pre-formed into the reactor seemed to be very effective in achieving short start-up period. Therefore the steady state was achived after 4 weeks and 1 week based on T-COD and S-COD, respectively.

This study was conducted to evaluate the effects of pressure and dissolved oxygen concentration on the activated sludge and to determine the optimum depth of deep shaft process. Some results from this study were summarized as follows. 1. It is considered that low sludge product in the activated sludge system maintaining high dissolved oxygen concentration is attributed to the increase of endogeneous respiration rate caused by the increase of aerobic zone in the sludge floc. 2. The increase of dissolved oxygen concentration does not affect to the increase of organic removal efficiency greatly and therefore the limiting factor is the substrate transfer into the inner part of floc. 3. The yield coefficient, Y is decreased in proportion to the increase of oxygen concentration. In this study, Y values arre ranged from 0.70 to 0.41 according to the variation of dissolved oxygen concentration from 18.0㎎/ℓ to 258 ㎎/ℓ. 4. The optimum depth of deep shaft process should be determined within the limits of non-toxicity to the microorganism and it is about 100m in this study.