• 생명과학회지
• /
• 제14권2호
• /
• pp.235-238
• /
• 2004

The possibility for developing multistage culture system to cultivate larvae by computer simulation with basic experiments was investigated. This culture system was composed of 3 stages. At the 1st stage, Chlorella sp. were cultivated and at 2nd stage Chlorella sp. were supplied to rotifer (Brachionus plicatilis), and rotifer were supplied to larvae at the 3rd stage. In this study, Chlorella sp. were cultivated by batch culture to search for the possibility of continuous feeding to rotifer at 2 nd stage. The maximum specific growth rate ($\mu$$_{max}$) of Chlorella sp. at the logarithmic phase was 0.56 [1/day]. Rotifer was cultivated by fed-batch culture at the feeding rate of Chlorella sp., $10^3$, $10^4$, $10^{5}$ and $10^{6}$ [cells/rotiferㆍh] to search for the relation between the feeding rate of Chlorella sp. and the growth rate of rotifer. As the results, the minimum feeding rate of Chlorella sp. was 2.8 ${\times}$ $10^4$ [cells/rotiferㆍday] in the multistage culture system, then the change of rotifer concentration at 2nd stage was simulated by computer. The required amount of rotifer for the growth of larvae was also increased as the growth of larvae. On the 9th day of the culture, the rotifer uptake rate of larvae was 250 [cells/rotiferㆍday]. Based on these basic experiments and results, It was suggested that the possibility of multistage culture system to cultivate larvae with continuous feeding of Chlorella sp. and rotifer.r.

• 한국결정성장학회지
• /
• 제3권2호
• /
• pp.117-124
• /
• 1993

연속성장법은 crystal growth chamber의 상부에 있는 reservoir에서 원료 분말을 연속적으로 공급하면서 도가니 하부에 용융대를 형성시킨 후, 종자결정을 용융대에 dipping하여 회전시키면서 아래로 끌어내려 단결정을 성장시키는 방법이다. 본 연구에서는 연속 성장법을 이용하여 silicon 단결정을 육성시켰으며 연속성장에 영향을 미치는 인자는 critical melt level, 원료공급속도, 성장속도, graphite crucible과 gruphite susceptor의 형태, work coil의 위치에 따른 graphite susceptor의 수직온도구배, 중력과 종자결정의 회전에 의한 원심력이 용융대의 안정화에 미치는 영향과 용융액 표면에서 일어나는 소결현상에 관해 고찰하였다.

• 한국세라믹학회지
• /
• 제29권7호
• /
• pp.539-543
• /
• 1992

The continuous growth method was developed for Mn-Zn Ferrite single crystals. It is a new process that the polycrystalline MnχZn1-χFe2O4 raw materials are supplied continuously from the powder feeding system to the crucible heated by R.F. induction and melted in the crucible, and after the single crystals seed is attached to crucible's hole, the crystals are pulled downward with rotation. Growing the crystals by using the growth method different from the conventional Bridgman or Floating Zone method, we defined the factors having effect on the crystal growing through the pre-experiments. They are temperature distribution in the crucible, melt velocity according to its height, wettability between the crucible's bottom and melt. Therefore, Mn-Zn Ferrite single crystals were to be grown by attaining the appropriate melt height in the crucible, powder feeding rate, temperature gradient between the crucible and interface, crystal growing speed, and this method was confirmed to have possibility for single crystal growing.

• 동력기계공학회지
• /
• 제18권6호
• /
• pp.84-90
• /
• 2014

The degradation of 2,3-dichlorophenol(2,3-diCP) by various advanced oxidation systems with continuous feeding of hydrogen peroxide including the ultraviolet/hydrogen peroxide, the Fenton and the photo-Fenton process has been conducted. The highest removal efficiency for 2,3-diCP in the aqueous phase was obtained by the photo-Fenton process among the advanced oxidation systems. In the photo-Fenton process, The removal efficiency of 2,3-diCP decreased with increasing pH in the range of 3 to 6, and it decreased with increasing initial concentration. As the intermediates of 2,3-diCP by photo-fenton reaction, 3,4-chlorocatechol and 2,3-dichlorohydroquinone were detected, thus the degradation pathways were proposed.

• Child Health Nursing Research
• /
• 제9권3호
• /
• pp.272-284
• /
• 2003

Purpose: The purpose of this research is to provide basic informations for the encouragements of premature infants' breast feeding. Method: From August 10 to October 9, 2002, we have carried out a statical research which surveyed 148 mothers of premature infants registered in NICU. The sample had generated cluster-randomly from 25 General Hospitals, all over the Korea peninsula and being surveyed with 74 questionnaires. Result: Mean hospitalized day of premature infants was 27.9 days. The mean total feeding period was 19.1 days and continuous breast feeding period 12.4days. They were interested in breast feeding education-they answered that they would join the breast feeding education if they were given the chance 87.8％. There was significant relation between babies fed only breast milk and the body weight of birth(p<.05). The reasons why mother gave the baby her breast milk include 'for her baby's health' and 'people said breast milk is good for babies' with a portion of 99％. The main reason why mothers could not execute breast feeding was 'the deficit of breast milk volume' 50.0％ and other reason were 'because of start to support more nutritions '18.2％, 'difficulty to carry out the breast milk to hospital'13.6％. The reasen why mothers could not try breast feeding at first were 'deficit of breast milk volume'37.0％, 'not to be prepared for breast feeding because of unexpected delivery'32.6％. Conclusion: We need a program to inform importance and excellent of the breast feeding and a plan to increase the premature infants' breast feeding through the importation of fortifier.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 1994년도 하계학술대회 논문집 A
• /
• pp.85-87
• /
• 1994

Feeding biological cells one by one is the key point in the manipulation of cells. The conventional valve systems have many difficulties in feeding cells one by one, because they shut the whole flow of fluids when they are closed and have possibilities of breaking the fragile cells. They need some other equipments for continuous supply of suspension and to protect the cells. We design a check valve for feeding biological cells one by one using polyimide all the silicon substrate. The cells are fed by hydraulic pressure through the isotropically etched cavity. When the suspension flows continuously along the channel the valve is bent by hydraulic pressure and a cell is fed to the outlet. We have studied a cell fusion device fabricated with polyimide and electroplating. If the designed check valve is located in front of the cell fusion device it is helpful to fuse two different kinds of cells.

• 보건교육건강증진학회지
• /
• 제17권1호
• /
• pp.61-79
• /
• 2000

This study to study and analyze the current state of infancy breast-feeding ＆ practice and related factors and to provide basic data for the effective practice of breast-feeding and breast-feeding percentage improvement. For the object, 474 mothers of the infants who were born between Jan. 1, 1998 and Dec. 31, 1998 were selected, and the survey period ＆ method were from Oct. 15, 1999 through Nov. 14, 1999 (1 month period) and telephone interview, respectively. To examine by month breast-feeding type, the average breast-feeding percentage in 1 month after a child's birth was 42.4%, but after 6 month it decreased to 23.0%. To see breast-feeding percentage by academic background, the breast-feeding of elementary school graduated mothers was 33.3%, which was highest, and it decreased as the academic background of mothers went better (p〈0.01). By employment state, the percentage for the mothers who were not employed was higher (24.6%) than that of those who were employed at the time, which was 8.0% (p〈0.001). There was no meaningful difference found in breast-feeding percentage by infant mothers age, delivery place, infant sex, child order in family, weight at the time of birth. To examine breast-feeding percentage by delivery method, natural delivery was 27.0% which was higher than 13.1% of Caesarean section (p〈0.01), and by breast-feeding experience before leaving the hospital, 35.6% of those who have breast-fed were breast-feeding while it was 16.4% for those who never did it while in the hospital (p〈0.001). After conducting logistics multi return analysis having breast-feeding percentage as a variable at the time of 6 months after babys birth, I found that infant mothers employment state, delivery method, and breast-feeding experience before leaving the hospital become meaningful variables. As unemployed mothers (p〈0.05), as chose natural delivery (p〈0.05), as experienced breast-feeding before leaving the hospital (p〈0.001), there was more tendency to do breast-feeding. Summing the above results, I would like to suggest the following to raise breast-feeding percentage. Firstly, systematic education about the importance and advantages of breast-feeding and correct breast-feeding method should be practised for women. Secondly, vacation before and after childbirth for working women should be practised and the support of systems for working womens breast-feeding such as installation of nursery in work place are needed. Thirdly, continuous publicity and education for natural delivery inducement is necessary, and for the ones who chose Caesarean section, recommendation of breast-feeding is also needed. Fourth, for breast-feeding within fastest time after delivery, rooming-in required and legal and systematic support is also needed. Lastly, in the governmental level, publicity for breast-feeding and breast-feeding recommending programs that promotes 10 rules for successful breast-feeding bringing-up, provided by UNISEF and WHO, are to be provided.

• Pediatric Gastroenterology, Hepatology & Nutrition
• /
• 제11권sup1호
• /
• pp.143-148
• /
• 2008

조사에 의하면 정상적으로 발달하는 유아 아동의 25%~40%정도가 발달의 어떤 단계에서 섭식에 문제를 보일 수 있다고 한다. 많은 경우에 특별한 전문가적 도움없이 발달 과정을 거치면서 문제가 저절로 해결되는 경우도 있으나, 그 중 일부는 성장과 발달 및 가족 생활에 큰 스트레스가 될 정도의 섭식문제를 보이며 심한 경우 그 문제가 오랫동안 지속될 수 있다. 섭식문제는 섭식 그 자체의 문제뿐 아니라 음식거부를 위한 다양한 문제행동을 수반하게 되는데, 기존의 연구 결과는 행동수정의 한 형태인 응용행동분석이 가장 효과적인 치료법이라 보고한다. 문제가 극심한 경우엔 다학제적 팀으로 구성된 전문적인 치료가 필수적이나, 중경도의 문제는 그 종류에 따라서 부모교육을 통해 해결될 수 있기도 하다. 섭식 치료에는 문제를 규명하는 평가 절차가 가장 먼저 선행되어야 하며, 이를 근간으로한 치료책을 개발하고 적용할 때 가장 효과적인 결과를 얻을 수 있다. 치료는 보이는 문제 유형에 따라 달라져야 하는데, 유아 아동들이 가장 빈번하게 보이는 섭식문제 종류와 그에 적절한 구체적인 방법들을 제시하였다. 마지막으로, 부모교육을 통해 유아 아동의 섭식문제를 다룰 때 전문가들이 고려해 주어야 하는 사항들에 대해서 열거해 보았다.

• 한국미생물·생명공학회지
• /
• 제27권4호
• /
• pp.327-332
• /
• 1999

A highly productive fed-batch fermentation process was developed for the production of L-ornithine by using a new stabilized strain, Breviabcterium ketoglutamicum BK52. Fed-batch cultures with a continuous feeding of the complex medium were conducted on various operating conditions. The optimal concentration of phosphate in the complex medium was 2.1g/L. The optimal feeding rate of L-arginine was 0.028g/L/hr. The optimal feeding point of the complex medium was determined to be at 40 OD of the cell mass. The final L-ornithine concentrations within 64hrs of cultivation in 5 and 50 liter fermenters were 73g/L and 71g/L, respectively. The maximum overall L-ornithine productivity was 1.14g/L/hr which was about 2 times higher than that of the conventional fed-batch culture with intermittent feeding. The overall productivity of the fermentation system is remarkably improved by employing the optimized conditions, and it offers a significant potential for industrial application.

• 한국미생물·생명공학회지
• /
• 제24권4호
• /
• pp.500-506
• /
• 1996

Bacillus subtilis SH-1 screened from coastal sea water of South Korea was used to produce bacteriolytic enzyme. The production of bacteriolytic enzyme by immobilized cells was investigated. The optimum conditions for the continuous production of the bacteriolytic enzyme using immobilized cells were 2.4 mm diameter of 0.3% alginate beads, 20 ml/h of substrate feeding rate and 20 l/min of aeration rate. A productivity of 76.5 to 88.0 units/ml could be obtained for 25 days by continuous column reactor under the optimum conditions.