• 한국추진공학회지
• /
• 제6권3호
• /
• pp.45-52
• /
• 2002

본 연구에서는 액체 로켓의 축방향 불안정성에 대한 개요와 국내 최초의 액체 추진로켓인 과학로켓 3호 (KSR-III) 추진기관 공급계 시스템에 대한 주파수 특성에 대한 결과를 다룬다. 공급계에 설치된 여러 구성품 중 벨로우즈와 벤튜리의 cavitation volume이 공급계의 주파수 특성에 미치는 영향을 파악하였다. 벨로우즈는 공급계의 고유진동수를 낮추는 데 큰 역할을 함을 알 수 있다. 또한 KSR-III의 산화제와 연료 공급계의 고유진동수는 각각 약 280Hz와 90Hz임을 알 수 있다.

• 한국추진공학회:학술대회논문집
• /
• 한국추진공학회 2017년도 제48회 춘계학술대회논문집
• /
• pp.1112-1114
• /
• 2017

액체 로켓 엔진은 채택되는 사이클, 하드웨어 구성, 기능 구현상의 짐벌 타입 등에 의해 구성품 배치와 레이아웃의 라우팅이 결정된다. 본 논문에서는 액체로켓엔진에 장착되는 주요 구성품을 기준으로 구동을 담당하는 헬륨(He) 공급 공압라인, 각종 퍼지 공압라인, 주 점화라인 등의 주요 유공압 라인의 개념 라우팅을 수행하였다.

• 한국분무공학회지
• /
• 제2권3호
• /
• pp.8-16
• /
• 1997

Ta investigate characteristics and spray of emulsified fuet we are mixed water with diesel oil using ultrasonic energy fuel feeding system. Separation ratio of emulsified fuel was shown good condition that of water content is small and longer ultrasonic energy adding time. Viscosity of emulsified fuel increased 79% with addition to water content and surface tension increased 1.6% in comparision to pure diesel oil. The SMD of emulsified fuel adding ultrasonic energy decreased with 3% in comparision to pure diesel oil. With increasing 5, 10% water content the SMD decreased 15.6, 20.1% in comparision to pure diesel oil. The mind-explosion was investigated with 4step.

• 한국축산시설환경학회지
• /
• 제5권3호
• /
• pp.203-216
• /
• 1999

Recent public concern about air pollution caused by swine production facilities has forced to develop the methods to reduce and control the swine odors. Swine odors were affected the life of pig farm neighborhoods, swine productivity, pig health, diseases, and human right, safety, sanity as negatively. The first approaches of control of swine odors are the change or improve of the classical management systems, which are manure treatment method, manure storage facility, phase feeding, sex-divided feeding, feeder type, liquid-slurry feeding, environment control of swine building and dust control of indoor swine facility. The methods to control odor emission from manure have to include the diet modification as nutritional basis. In recent, research emphasis has focused on manipulating the swine diet to increase the nutrient utilization of the diet to reduce excretion products and reduction of odors. There are lots of feed additives and pit additives introduced as practical basis for reducing odor emissions. The ozone treatment method is candidate as the good system for reducing swine odor. But this system is still too expensive to practice in present.

• 혜화의학회지
• /
• 제5권2호
• /
• pp.319-332
• /
• 1997

Experiments were performed to determine the effects of the Shiryungtang (SRT) liquid extract on the hypertension and the hyperlipidemia induced by cholesterol in Sprague-Dawley rat(SDR) and Spontaneous Hypertensive rats(SHR). The results were obtained as follows : 1. The blood pressures of Sample A, B were decreased significantly compared with control group. First day, in case of Sample B, the blood pressure depressed after 1 and 2 hour. 2. After 11days of feeding with SRT, the blood pressure was decreased significantly in the treated group as compared with the control group. 3. After 11days by fed with SRT, the cholesterol had no significant in all treated group compared with the control group. 4. After 11days by fed with SRT, the triglyceride had no significant in all treated group compared with the control group. 5. The cholesterol of hypercholesterolemic rat induced by feeding with cholesterol was decreased significantly in all treated group compared with the control group. 6. The triglyceride of hypercholesterolemic rat induced by feeding with cholesterol was decreased significantly in all treated group compared with the control group. 7. The HDL-cholesterol of hypercholesterolemic rat induced by feeding with cholesterol was decreased significantly in all treated group compared with the control group. 8. The phospholipid of hypercholesterolemic rat induced by feeding with cholesterol was decreased significantly in Sample B of the treated group. 9. The total lipid of hypercholesterolemic rat induced by feeding with cholesterol was decreased significantly in Sample B of the treated group. 10. The total protein of hypercholesterolemic rat induced by feeding with cholesterol was decreased significantly in Sample B of the treated group. 11. The albumin of hypercholesterolemic rat induced by feeding with cholesterol was decreased significantly in all treated group compared with the control group. With the above result, it is thought that Shiryungtang can be applied effectively to the hypertension and hyperlipidemia.

• Journal of Nutrition and Health
• /
• 제12권1호
• /
• pp.23-30
• /
• 1979

For the purpose of investigating the weaning practice for infants, this study of 251 infants aged from 3 months to 2 years old was conducted in Daejeon City during the the period of August 9 through 23, 1978. The results obtained were as follows: About 60% of the infants were breast-fed, 27.6%, mixed-fed, and 12.0%, bottled-fed. The reason for bottle-feeding was either the lack of breast-milk secretion or ill-health of mothers. There was no significant difference in the feeding methods according to a level of mother's education. Sixty precent of the infants began to be weaned 6. months. The most of the infants were completely weaned within 18 months. The knowledge on weaning was mainly obtained from the publications, such as newspapers, journals for women, child care booklets, etc. The difficulties in the weaning practice were the shortage of knowledge on weaning and the unacceptability by the infants. Liquid or semi-liquid foods were firstly given to the more than 60% of the infants as introducing weaning foods, while 23.3% of the babies were given solid foods. Interestingly, the earlier the birth order was, the more babies were given liquid or semi-liquid foods, The motives for weaning was either the boby's demand for other foods than milk(41.3%) or the lack of breast-milk secretion (31.3%). In the selection of supplementary foods, the nutritional value was given the highest consideration) (54.9%). many mothers (64.2%) prepared supplementary foods for infants at home, while 23.1% used commercial body foods and 12.7% gave infants adult's meals as supplementary foods. The major materials for home-made supplementary foods were fruits and vegetables (41.5%) and cereals (37.5%). The commercial supplementary foods (mainly powdered from) were not used much (never used; 53.6%) and even in the babies, who had consumed them once, nearly half of the babies (42.9) did not eat well. Accordingly, the many mothers (68.8%) welcomed the development of the domestic supplementary foods in good quality and one-third (31.2%) responded that they would consume them regardless of the price.

• Asian-Australasian Journal of Animal Sciences
• /
• 제13권4호
• /
• pp.511-515
• /
• 2000

Early weaning is a means of breaking the disease cycle from sow to piglet as well as capitalising on the enormous growth potential of the pig. However, the transition from milk to dry diets results in a growth check. Feeding of supplemental milk, fermented to reduce pH and enterotoxigenic bactetial proliferation, may be a means of gradually weaning pigs on to solid feed. This study involved 216 pigs weaned from the sow at 12 days of age, allocated to groups of 6 males and 6 females per weaner pen and allowed ad libitum access to a pelleted diet. In addition, half the pigs were given supplemental fermented skim milk for the first 8 days after weaning. Feeding supplemental fermented milk increased feed intake (104 vs. 157 g DM/d, p=0.011), average daily gain (-3 vs. 112 g/d, p<0.001) and feed conversion efficiency (0.01 vs. 0.81, p=0.003) over the first 8 days after weaning. The improvements observed in the supplemented pigs continued to be augmented such that, by 42 days of age, the pigs that had received supplemental fermented milk were heavier (9.6 vs. 11.5 kg, p=0.003) than their unsupplemented counterparts. Feeding fermented supplemental milk to early-weaned pigs can improve growth performance in the immediate and subsequent post-weaning period.

• 한국세라믹학회지
• /
• 제45권7호
• /
• pp.380-386
• /
• 2008

Optimized volume production of nanoscale phosphor powders synthesized by radio frequency (RF) plasma process was developed for the application to plasma display panels. The nano powders were synthesized by feeding the both solid and liquid type precursors, and nanoparticle phosphors were characterized in terms of particle size, shape, and photoluminescence (PL) intensities. Computer simulation was performed in advance to determine the process parameters, and nano phosphors were evaluated by comparing with current commercial micron-sized phosphor powders. Practical feeding of both solid and liquid type precursor was proved to be effective for volume production.The developed process showed a potential as a production method for red, blue and green phosphor although the PL intensity still needs further improvement.

• 한국추진공학회:학술대회논문집
• /
• 한국추진공학회 2011년도 제37회 추계학술대회논문집
• /
• pp.793-794
• /
• 2011

발사 전 발사체에 공급되는 추진제는 엔진의 정상작동을 위해 설정된 추진제 온도범위 내로 공급되어야 하며, 이는 발사체 공급계 시스템 내에서의 온도변화도 고려되어 발사 전 지상공급시스템 운용 절차에 반영된다. 본 논문에서는 나로호 발사대 액체산소 충전시스템의 액체산소 충전 온도 제어를 위한 시스템 운용절차와 액체산소 냉각방법에 대해 고찰한다.

• 유체기계공업학회:학술대회논문집
• /
• 유체기계공업학회 2006년 제4회 한국유체공학학술대회 논문집
• /
• pp.551-554
• /
• 2006

Inhibition of propellant temperature rising in liquid propulsion rocket using cryogenic fluid as a propellant is very important. Especially propellant temperature rising during stand-by after filling and pre-pressurization can bring into cavitation in turbo-pump. One of the method preventing propellant temperature rising in cryogenic feeding system is recirculating propellant through the loop composed of propellant tank, feed pipe, and recirculation pipe. The circulation of propellant is promoted through gas-lift effect by gas injection to lower position of recirculation pipe. In this experiment liquid oxygen and gas helium is used as propellant and injection gas. Under atmospheric and pressurized tank ullage condition, helium injection flow-rate is varied to observe the variation of recirculating flow-rate and propellant temperature in the feed pipe. There is appropriate helium injection flow-rate for gas-lift recirculation system.