• 환경위생공학
• /
• 제16권2호
• /
• pp.38-46
• /
• 2001

In this work, the heterogeneous ion exchange membrane was used in a electrodialysis apparatus to treat a Ni planting rinse water because the heterogeneous ion exchange membrane was excellent efficiency as compared with low manufacturing cost, was easy to make, and had a good mechanical properties. For a regeneration of membrane and to obtain the optimal condition for a scale-up of apparatus after treating Ni plating rinse water, we would find about the limiting current density and the concentration polarization. When the Ni plating rinse water 150mg/L was treated with the electrodialysis apparatus using the heterogeneous ion exchange membrane, the limiting current density was about $1.49{\;}mA/\textrm{cm}^2$. And the limiting current density increased with the flow rate and concentration of Ni plating rinse water. We recognized that the used membrane could be reused by periodic backwashing because efficiency was constant when the membrane was backwashed after treating wastewater.

• 한국식품조리과학회지
• /
• 제21권5호
• /
• pp.703-708
• /
• 2005

The purposes of this study were to establish washing conditions for vegetable salad to reduce the microbial hazard by using sodium hypochlorite solution and eventually to implement HACCP for salad processing. By using the salad production line of Shinkeum Co. located in Gwacheon, Gyunggi-do, salad samples were washed under several washing conditions (chlorine dip period, chlorine concentration, rinse time, etc.) to determine the most effective conditions. The original washing line consisted of 3 baths (100 ppm chlorine water dip, water rinse, and water rinse), each with a capacity of 100 L of tap water and 5 kg of salad. First, the salad samples were washed with 100 ppm of sodium hypochlorite solution for various dip times (3, 6, 9, 12 min); however, only a 1 log- or less-reduction in total microbial counts was achieved in all groups and the time of chlorine water dip was not a significant factor in reducing the microbial hazard. When another water bath was added before the chlorine water dip (4-bath washing), a 2 log-reduction in total microbial counts was achieved. This result suggested the importance of pre-dipping salad materials in water before chlorine treatment to reduce the organic load on the surface of the vegetables. Coliforms were not detected at all after washing. As the concentration of chlorine $(50{\sim}150\;ppm)$ and rinse time $(0.5{\sim}2\;min)$ increased, greater microbial reduction was achieved; however, physical damage of the salad was observed. Finally, the optimum washing conditions for salad were determined as 3 min-water dip, 3 min-chlorine (100 ppm) dip, 2 min-rinse, and 2 min-rinse.

• 한국표면공학회지
• /
• 제36권2호
• /
• pp.194-199
• /
• 2003

Polarization measurements were peformed to investigate the electrochemical behavior of copper ions and limiting current density in waste rinse water from copper electroplating processes. A newly designed cyclone type electrolyzer was tested to recover the copper powder. Synthetic solutions were prepared using analytical grade $CuSO_4$ to the desired waste water concentration and pH was adjusted with $H_2$$SO_4$. Electrowinning was peformed at room temperature and the solution was cycled with a pump. Results showed that more than 99 percent of Cu was recovered and the size of the recovered Cu powder ranges from 0.1 - $0.5\mu\textrm{m}$. The chemical composition of the Cu powder mainly consists of $Cu_2$O and Cu and can be easily reduced to pure Cu powder.

• 한국패션뷰티학회지
• /
• 제4권3호
• /
• pp.13-17
• /
• 2006

Perm is one the of the most common thing in a beauty salon like hair-cut and hair perm needs processing solutions which is chemical substances. Those chemical substances damage the hair cuticle. Damaged hair cuticles with mistakes of perm will follow with the next performance and it will cause more damage to hair. As damage of hair cuticle become worse, it is harder to recover the hair cuticle like before. Therefore, this study shows that plain rinse is the way to reduce the damage of hair cuticle with perm as much as possible. With experiments, I suggest the right way to do plain rinse to satisfy customers' demand and reduce the damage. During the research, I figured that plain rinse with the knowledge, structure of hair cuticle, principle of perm and plain rinse, is very needed. The hair with plain rinse have more elastic curl and have less scales which came off from hair cuticle than the hair without plain rinse. This experiment concludes that hairdresser has to figure out about the time, temperature and type of water depends on the degree of damaged hair of customers. In order to perm, there is no way to not to use chemical substances to perm. Therefore, hairdresser has to choose suitable processing solutions and right steps, and as this is the age of 'well-being' boom, hairdresser must try to keep the healthy hair. Consequently, in order to meet the demands and conditions of customers, hairdresser needs to find the right method to do plain rinse and use the method in perm.

• 농업과학연구
• /
• 제2권2호
• /
• pp.423-431
• /
• 1975

석회수(石灰水)(Limewater)가 낙농세척(酪農洗滌)-살균제(殺菌劑)로서 이용가치(利用價値)가 있는지를 구명(究明)하기 위(爲)하여 idophore와 비교(比較)하여 세척(洗滌)-살균시험(殺菌試驗)을 실시(實施)한 결과(結果)는 다음과 같다. 1. 착유백수(搾乳白數)에 따른 유석(乳石) 형성(形成)은 착유(搾乳) 6일(日) 착유(搾乳) 전세척제(前洗滌劑)로서 idophore를 처리(處理)(0.1119~0.876mg per sq. 10Cm)한 것이 가장 적었고 다음이 석회수처리(石灰水處理) (0.4639~1.5831mg)이며 무처리시(無處理時)(0.6230~4.3575mg)가 가장 많았다. 2. 착유전세척수(搾乳前洗滌水)의 온도(溫度)가 높을 수록 idophore처리(處理), 석회수처리(石灰水處理) 및 수도수(水道水) 처리(處理)는 모두 유석(乳石) 형성(形成)의 증가(增加)를 보였다. 3. 유지방(乳脂肪)의 제거(除去)는 석회수처리(石灰水處理)($10{\ell}$ 세척시(洗滌時) 78~88% 제거(除去))였으며 효과적(效果的)이였고 다음이 idophore 처리(處理)(66~86% 제거(除去))였으며 수도수처리(水道水處理)(56~68% 제거(除去))는 가장 효력(效力)이 떨어졌다. 4. 우유고형물(牛乳固形物) 제거효과(除去效果)는 idophor 처리(處理)($10{\ell}$ 세척시(洗滌時)73-78%제거(除去))와 석회수(石灰水) 처리(處理)(68~73%)가 비슷했으며 수도수처리(水道水處理)(44-52% 제거(除去))가 가장 떨어졌다. 5. 세척제(洗滌劑) 살균효과(殺菌效果)는 idophore 처리(處理)가 석회수처리(石灰水處理)보다 강(强)했으나 큰 차이(差異)는 보이지 않았다. 6. idophore 및 석회수처리(石灰水處理)는 모두 위생적(衛生的)인 우유생산(牛乳生産)을 기(期)할 수 있었다.

• 전자공학회논문지D
• /
• 제35D권2호
• /
• pp.60-69
• /
• 1998

Polysilicon surface mdoification tecnique is developed to reduce the sticking of microstructures fabricated by micromachining. Modified anti-sticking grain holes are simply formed by two-step dry eth without additional photolithography nor deposition of thin films. Both process-induced sticking and in-use sticking are successfully reduced more than two times by adopting grain holed polysilicon substrate. A sticking model for cantilever beam is derived. This model includes bending moment stems from stress gradient along the thickness directionof structural polysilicon. Because the surface tension of rinse liquid and the surface energy of the solids to be stuk tend to decrease in recently developed anti-sticking techniques, the effect of stress gradient will play an important role to analyze the sticking phenomena. Effect of the temperature during post-release rinse and dry is modelled and verified experimentally. Based on developed anti-sticking polysilicon structure and the sticking model, sticking of microstructure, fabricated by simple wet process including sacrificial layer etch and rinse with deionized water without special equimpment for post-release rinse and dry was alleviated more than 3.5 times.

• 폴리머
• /
• 제26권5호
• /
• pp.551-558
• /
• 2002

술폰산형 섬유이온교환체를 이용하여 도금 폐수 중 니켈 이온 분리를 위해 각각의 조건에 따른 니켈 이온에 대한 흡착 특성을 관찰하였다. 술폰산형 섬유이온교환체의 함수율은 술폰화도 극성이 클수록 크게 나타났으며 이온교환용량은 술폰화도가 증가함에 따라 증가하였으며 술폰화도 16%에서 3.38 meq/g로 높게 나타났다. 니켈이온의 흡착은 pH 변화에 따라 크게 변화하지 않았고 모든 흡착은 10분 이내에 약 7.5 mg/min의 흡착속도로 매우 빠르게 평형에 도달하였다. 재생 시 흡착용량은 7회까지 3.15 meq/g으로 거의 100% 가까이 탈착되었으며 그 이상에서는 2.01 meq/g으로 약간 감소하는 것으로 보아 본 연구에 사용한 이온교환체는 내구성에 문제가 없는 것으로 판단되었다. 한편 흡착평형 시간은 L/D의 값이 증가함에 따라 선형적으로 증가하였으며, 최대 흡착용량은 각각 2.71∼3.01 meq/g으로 약간 증가하였고 L/D의 변화에 크게 영향이 없는 것으로 보아 L/D<2로 흡착칼럼의 설계가 가능할 것으로 사료되었다. 또한 이온교환 섬유의 충전비가 일정할 때 pH 변화에 따른 니켈 이온의 흡착량은 산성 pH에서는 큰 변화가 없는 것으로 보아 도금수세액의 pH가 산성인 점을 고려할 때 pH 5 이하가 적합한 것으로 판단되었다.

• 한국표면공학회지
• /
• 제8권2호
• /
• pp.14-19
• /
• 1975

• Restorative Dentistry and Endodontics
• /
• 제24권2호
• /
• pp.392-398
• /
• 1999

The purpose of this study was to assess the effect of catalase used following bleaching for the elimination of hydrogen peroxide residues from human teeth on the microleakage at the tooth-resin composite interface. In this study, class V cavities were prepared on the buccal or lingual surfaces of seventy extracted human molar teeth, and crown of sixty teeth were immersed in 30% hydrogen peroxide at $37^{\circ}C$ for 5 days except for negative control group. Then the teeth were rinsed with water and distributed randomly into seven groups of 10 each and were conditioned as following Negative control group: No bleaching Positive control group : bleaching and no application of catalase (C-40) Experimental group 1 : one cycle of catalase application for 3 min. and water rinse for 2 min. after bleaching Experimental group 2 : two cycles of catalase application for 3 min. and water rinse for 2 min. after bleaching Experimental group 3 : three cycles of catalase application for 3 min. and water rinse for 2 min. after bleaching Experimental group 4 : four cycles of catalase application for 3 min. and water rinse for 2 min. after bleaching Experimental group 5 : five cycles of catalase application for 3 min. and water rinse for 2 min. after bleaching The cavities of each groups were restored with composite resin. The teeth were thermocycled, stained with 2% methylene blue, and sectioned buccolingually. Degree of dye penetration at tooth-restoration interfaces were examined by stereomicroscope(${\times}30$) at occlusal and gingival margin The results were as follows : 1. On the occlusal margin, there was no significant difference in the microleakage between the negative coltrol group and experimental groups (p>0.05). But on the gingival margin, experimental groups showed higher microleakage than the negative coltrol group (p<0.05). 2. On the occlusal margin, positive coltrol group showed higher microleakage than experimental groups (p<0.05) and among the experimental groups, group 1 showed higher microleakage than group 3, 4, 5 (p<0.05). 3. On the gingival margin, there was no significant difference between the positive coltrol group and experimental groups, and between experimental groups (p>0.05). The result indicated that catalase used in bleached cavity for the elimination of hydrogen peroxide residues from human teeth maybe reduced microleakage at the tooth-resin composite interface.

• 한국막학회:학술대회논문집
• /
• 한국막학회 2001년도 추계 총회 및 학술발표회(한국막학회)
• /
• pp.111-114
• /
• 2001