• 환경위생공학
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• 제23권2호
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• pp.55-63
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• 2008

All over the world, the existing process of water purification needs more flocculants and chlorine due to a gradual decline in the quality of source water. Therefore, the problem of the remaining aluminium and DBPs in purified water is on the rise. To solve this problem, the process of membrane filter has recently come into the spotight. This study reaches the following conclusions concerning TMP variation in order to solve the dropping of flux throgh a membrane filter when operating a membrane filter system in the process of water purification. 1. In case that a cohesion-precipitation process was introduced to pre-treatment of a membrane filter, initial TMP was very satisfactory(0.27kg/cm) in producing the constantly safe quality of water, $0.04{\sim}0.1$(mean 0.05) NTU by pouring 2mg/l of PACI(10% $Al_2O_3$) used for the existing process of water purification in high-density turbidity at a dry or flood season and at occurrence of high algae. 2. As flux increased at 0.5m/day.m, TMP increased 0.05 kgf/cm. 3. As filtering, operation mode of PVDF MF membrane filtering was 48 minutes and 1 cycle of back washing was 42 minutes, flux was increased 1.5m/day.m and TMP increased $0.25{\sim}0.27kgf/cm$. Without back washing, TMP increased 0.03 kgf/cm per a cycle.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2013년도 제45회 하계 정기학술대회 초록집
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• pp.244.2-244.2
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• 2013

Contact Pattern을 Plasma Etching을 통해 Pattering 공정을 진행함에 있어서 Plasma 내에 존재하는 High Energy Ion 들의 Bombardment 에 의해, Contact Bottom 의 Silicon Lattice Atom 들은 Physical 한 Damage를 받아 Electron 의 흐름을 방해하게 되어, Resistance를 증가시키게 된다. 또한 Etchant 로 사용되는 Fluorine 과 Chlorine Atom 들은, Contact Bottom 에 Contamination 으로 작용하게 되어, 후속 Contact 공정을 진행하면서 증착되는 Ti 나 Co Layer 와 Si 이 반응하는 것을 방해하여 Ohmic Contact을 형성하기 위한 Silicide Layer를 형성하지 못하도록 만든다. High Aspect Ratio Contact (HARC) Etching 을 진행하면서 Contact Profile을 Vertical 하게 형성하기 위하여 Bias Power를 증가하여 사용하게 되는데, 이로부터 Contact Bottom에서 발생하는 Etchant 로 인한 Damage 는 더욱 더 증가하게 된다. 이 Damage Layer를 추가적인 Secondary Damage 없이 제거하기 위하여 본 연구에서는 원자층 식각방법(Atomic Layer Etching Technique)을 사용하였다. 실험에 사용된 원자층 식각방법을 이용하여, Damage 가 발생한 Si Layer를 Secondary Damage 없이 효과적으로 Control 하여 제거할 수 있음을 확인하였으며, 30 nm Deep Contact Bottom 에서 Damage 가 제거될 수 있음을 확인하였다. XPS 와 Depth SIMS Data를 이용하여 상기 실험 결과를 확인하였으며, SEM Profile 분석을 통하여, Damage 제거 결과 및 Profile 변화 여부를 확인하였으며, 4 Point Prove 결과를 통하여 결과적으로 Resistance 가 개선되는 결과를 얻을 수 있었다.

• 한국지하수토양환경학회지:지하수토양환경
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• 제26권4호
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• pp.1-7
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• 2021

The removal of PCBs (Polychlorinated biphenyls) in aqueous phase was investigated in the ultraviolet (UV) process, ultrasonics (US) process and ultraviolet/ultrasonic (UV/US) process using PCB No.7 and Aroclor 1260. For PCB No.7 relatively high removal efficiency over 90% was obtained during 20 min in the UV process and UV/US process. On the other hand, lower removal efficiency of 50 - 70% was achieved for it consisted of individual congeners of PCBs containing 3~8 of chlorine atom. It was found that the dechlorination reaction (the photolytic cleavage of C-Cl bond) was considered as a main removal mechanism in the UV process while PCBs were removed by cavitation-induced radical reaction in the US process. No significant dechlorination occurred in the US process. Consequently, it was suggested that the UV process or UV/US process was applicable for the removal of PCBs in aqueous phase in terms of the removal efficiency and operation time. In addition, the application of saturating gas such as Ar and Air could be considered to control redox condition and enhance the severity of acoustic cavitation for the removal of PCBs.

• 한국환경과학회지
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• 제30권7호
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• pp.537-545
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• 2021

This study aimed to investigate the improvement effect of 5% (w/w) mung bean (Phaseolus aureus L.) on lipid composition and protein concentration in hyperlipidemic rats. Seven-week-old male (Sprague-Dawley) rats were divided into four groups (n=6, each), and fed experimental diets containing mung bean meal [basal diet+5% (w/w) mung bean (BM), basal-hyperlipidemic diet+5% (w/w) mung bean (BHM)], basal-hyperlipidemic diet (BH), and control (basal diet, BD). Lipid composition in the mung bean diet groups (BM and BHM) evidenced significant reductions in serum total cholesterol, low-density lipoprotein cholesterol, atherosclerotic index, cardiac risk factor, triglyceride, phospholipid, free cholesterol, cholesteryl ester, blood glucose, nonesterified fatty acid, and an elevation in high-density lipoprotein cholesterol. The serum albumin/globulin ratio was increased in mung bean diet-supplemented rats compared to that in hyperlipidemic rats (p < 0.05). Total calcium, phosphorus and potassium concentrations in sera were higher in the BM, BHM and BD groups than in the BH group. Concentrations of sodium and chlorine in sera were lower in the mung bean diet-supplemented groups than in the hyperlipidemic group. The in vivo experiments showed that ingestion of mung bean was effective in improving lipid composition, protein concentration, and blood glucose.

• 한국어병학회지
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• 제37권1호
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• pp.139-145
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• 2024

In this study, nylon mash and silicone tube mainly used as shrimp farm equipment were contaminated with Enterocytozoon hepatopenaei (EHP) which is the cause of Hepatopancreatic microsporidiosis (HPM), and were treated with calcium hypochlorite or UV-C disinfection methods for EHP eradication. As a result, similar with the control group (not disinfected), EHP was detected on the nested PCR until the 10 days in the UV-C single treated group. On the other hand, EHP was not detected from 7 days in calcium hypochlorite single treated group (total concentration 200 ppm as available chlorine), and combination of calcium hypochlorite and UV-C treated group revealed no detection of EHP from 3 days. It is appropriate that treated with UV-C and calcium hypochlorite for 3 days or single treated with calcium hypochlorite for 7 days to eradicate EHP on contaminated instrument used in shrimp farms. In contrast, disinfection effect of only using UV-C is very low.

• 한국환경보건학회:학술대회논문집
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• 한국환경보건학회 2005년도 국제학술대회
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• pp.263-272
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• 2005

Chlorine disinfection has been used in drinking water supply to disinfect the water-borne microbial disease which may cause to serious human disease. it is still the least costly, relatively easy to use, Chlorination is the primary means to disinfect portable water supplies and control bacterial growth in the distribution system. However, chlorine reacts with natural organic matter(NOM), that presents in nearly all water sources, and then produces disinfection by-products(DBPs), that have adverse health effects. Although the existent DBPs have been reported in drinking water supplies, it is not feasible to predict the levels of the various DBPs due to the complex chemistry reaction involved. 1. The objectives of this study is to investigate seasonal variation difference concentration of DBPs in the plant to tap water. The average concentration of THMs was 20.04 ${\mu}g/{\ell}$ , HAAs 8-15 ${\mu}g/{\ell}$ , HANs 2-4.5 ${\mu}g/{\ell}$ respectively. 2. Distant variation of DBPs furmation by the distance is that THMs concentration increased by 17% at 2km point from the plant and by 28% at 7km and HAAs, HANs also increase each by 16%, 32% at 2 km from the plant and 35%, 56% at 7 km. DBPs increase in water supply pipe continually, 3. The seasonal occurrence of BBPs is that in May and August DBPs concentration is very higher than in march, in May DBPs concentration is highest. The temperature is main factor of DBPs formation, precursor also. 4. Precursor which was accumulated for winter flowed into the raw water by flooding in spring and summer and produced DBPs. 5. Therefore for the supply of secure drinking water, it is required to protect precursor of flowing into raw water and to add to BCAA and DBAA to drinking water standards.

• 분석과학
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• 제16권3호
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• pp.249-260
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• 2003

한강에서 채취한 원수에 염소소독제인 hypochlorite를 $10{\mu}g/m{\ell}$의 농도로 투여한 후 1시간~14일까지 TOC (total organic carbon), 잔류염소량 및 탁도 등을 측정하고 THMs (trihalomethanes), HANs (haloacetonitriles), HKs (haloketones), chloral hydrate 및 HAAs (haloacetic acids) 등의 염소소독 부산물의 생성율을 조사하였다. 그 결과 잔류염소량은 투여후 1시간 경과 시 $6{\mu}g/m{\ell}$ 이상에서 14일째에 $1.23{\mu}g/m{\ell}$으로 감소하였으며 TOC 및 탁도는 큰 차이가 없었다. 7일 후 발생한 총 소독부산 물의 농도는 $101.3ng/m{\ell}$ (789.6 nM)이며 이 중 THMs이 69%로 가장 큰 비중을 차지하였다. 그 외에 HAAs가 19%, chloral hydrate가 10% 정도 검출되었으며, HANs와 HKs 및 chloropicrin 등은 미량 검출되었다. THMs 중에서는 chloroform이 $61.5ng/m{\ell}$로 총 THMs 중 약 89% 정도를 차지하였으며 HANs 중에서는 DCAN이 95%인 $0.72ng/m{\ell}$, HAAs 중에서는 TCAA가 50% 등으로 가장 높은 비율로 검출되었다. 각 부산물의 발생량의 상관관계를 조사한 결과 THMs과 HANs의 경우 THMs의 농도가 $40ng/m{\ell}$인 지점을 경계로 HANs과 경쟁적 발생관계가 있음이 나타났다. HAAs의 경우는 특별한 경향성을 나타내지 않았으나 전체적으로 초기에 산화상태가 큰 화합물에서 산화상태가 작은 화합물로 점차 변화하는 것으로 관찰되었다.

• 한국재난정보학회 논문집
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• 제18권2호
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• pp.306-313
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• 2022

연구목적: 본 연구에서는 암모니아 화학사고 발생 시, 사고 피해 최소화와 사고예방을 위한 현 제도의 개선방안을 제시하고자 한다. 연구방법: 화학사고 발생통계자료를 바탕으로 빈번한 화학사고를 일으키는 대표적인 독성물질 중 하나인 암모니아를 누출물질로 선정하였다. 또한, 실제 암모니아 화학사고 발생 사례를 바탕으로 CARIS 모델링을 활용해 암모니아, 염산, 염소의 피해영향범위를 비교해보았으며, 현 제도의 문제점을 파악하였다. 연구결과: 암모니아 화학사고 발생 시 주위에 확산되는 영향범위를 산정한 결과 염산의 사고영향거리보다 더 길게 나타났으며 염소의 사고영향거리보다는 더 짧게 나타났다. 또한, 암모니아, 염산, 염소 사고 발생시 아파트, 학교 등의 민감수용체가 존재하고 있어 영향을 미칠 수 있는 것으로 나타났다. 결론: 암모니아를 취급하는 사업장에 대해서 화학사고예방관리계획서, 통계조사 등의 제출여부를 파악하는 것이 필요하다고 판단되며 구체적인 세부지침 및 검토가 필요하다고 사료된다. 또한, 암모니아 취급사업장의 DB 구축이 필요하다고 판단되며 관계기관들 간의 정보공유 및 합동점검 등을 지향하여야 한다고 사료된다.

• 대한환경공학회지
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• 제22권4호
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• pp.661-669
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• 2000

본 연구는 6개 관종으로 구성된 모의순환관로시스템에서 정수의 부식성을 조절하여 관로내의 부식을 저감시킬 목적으로 pH 및 알칼리도 조절 수질제어시스템을 운전하여 관로의 금속용출 저감 및 부식성 지수의 변화를 파악하고, 수질제어에 따른 다른 수질인자들 즉, 미생물, 잔류염소농도, 그리고 소독부산물(THMs) 및 이온류 등의 농도 변화를 평가하고자 하였다. 실험결과, pH 및 알칼리도 조절을 통한 수질제어시스템은 부식성 지수의 변화와 함께 금속의 용출율이 감소하였으며, 소독부산물(THMs)의 형성 및 미생물의 재성장에도 별다른 영향을 미치지 않는 것으로 나타나 수질제어에 따라 관 표면에 형성된 탄산칼슘 피막은 부식저감과 함께 관로내 수질의 안정화를 가져오는 것으로 판단된다. 따라서 pH 및 알칼리도 동시 조절을 통한 부식성 수질 제어시스템은 고형물의 침전 및 용출에 가장 큰 영향을 미치는 pH 및 TIC 등 수질인자들을 안정화시켜 전체적인 수돗물의 수질관리에 매우 효과적일 것으로 사료된다.

• 한국환경보건학회지
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• 제22권1호
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• pp.45-50
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• 1996

The application of HACCP system, which was adopted by Codex Alimentarius Committee for the safe meat and poultry production, is one of the urgent task for competing in the world trade markets. But there have been no useful analytical studies to identify the causes of contamination in the poultry meat processing plants in Korea. This study was conducted to investigate the potential hazards during the operations by the microbiological examination for the poultry meat processing plant (20,000 birds capacity a day) located in Kangwon province. In spite of air contamination of work places, it may not directly affect the surface contamination of poultry meats. But the risk of Campylobacter jejuni/coli contamination was high. The number of total count was decreased about ten times, but remarkable changes of microbial contamination could not be recognized in each procedure during the operations. The washing water was already contaminated as much as $10^{3-6}CFU/ml$ in SPC before the operations. It means that to keep water tanks hygienic is a primary step to prevent the occurrences of microbial contamination. The overflow and recirculation of water in scalding, washing, and chilling was aslo an important factor for a hygienic control. Based on this study, the followings could be regarded as an important factors for hygenic control in the poultry slaughtering plants on a small scale. The temperature of water used for scalding should be constantly maintained on a required temperature, and the overflow rate of 1~1.5 liter per bird. The carcass surface and the body cavity should be washed thoroughly and the cross-contamination due to facilities, workers, and tools should be prevented. The chilling water sholud be maintained under 5$\circ$C of temperature with ice and overflow, and residual chlorine level of 50 ppm.