• Asian-Australasian Journal of Animal Sciences
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• 제11권1호
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• pp.30-34
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• 1998

To compare response of feeding concentrate mixtere and wheat straw (Group I) with either urea molasses liquid diet (UMLD) as sole ration (group II) or UMLD (similar to protein equivalent of concentrate mixture) plus wheat straw (group III) on intake and utilisation of nutrients and overall performance, twelve crossbred adult male cattle (Holstein Friesian ${\times}$ Hariana) aged about 2.5 years and weighing 342 kg were randomly allotted into three equal groups following completely randomised design and fed respective diets for a period of 60 days. Thereafter, a metabolism trial of seven days duration was conducted to assess nutrient utilisation and nitrogen balance. Animals fed UMLD as sole ration consumed significantly (p < 0.01) less amount of most of the nutrients as compared to other two groups, except crude protein, intake of which was higher in this group but it was comparable between II and III and III and I. On the other hand, digestibilities of nutrients were higher (p < 0.01) in group II, though it was comparable between other two groups, except ADF, the digestibility of which was lower in group II. Inspite of positive nitrogen balance in all the three groups, being significantly (p < 0.01) higher in group I, animals of group II and III lost their body weight especially to the utmost extent in group II, although the amount of energy (TDN) intake were similar statistically. Results indicate that during a scarcity period and economic compulsions, feeding of UMLD can be practised to replace only concentrate mixture from the maintenance ration of adult crossbred cattle for shorter duration as roughage part seems to be essential for the normal functioning of the rumen microbes and overall performance of the animals.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2002년도 학술대회지
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• pp.495-498
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• 2002

This article deals with the introduction of longitudinal instability of liquid rocket (pogo) and the analytical results on the frequency responses of KSR-III propulsion feeding system. Both the stiffness of bellows and the cavitation volume of venturi affect the frequency response of the feeding system. Especially, bellows has a great roll to reduce the natural frequency of the feeding system. Also, oxidizer and fuel feeding systems of the KSR-III have natural frequencies of ${\~}280Hz\;and\;{\~}90Hz$, respectively.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2006년도 제27회 추계학술대회논문집
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• pp.122-126
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• 2006

터보펌프식 발사체 추진기관의 기체공급계 개발과정을 통하여 두 가지 방식의 가압시스템과 저중량 배관시스템에 대한 국산화 개발을 수행하였다. 서브시스템 시험을 통해 액체산소 얼리지 압력을 일정하게 유지시키기 위한 1단 및 2단 감압방식 가압시스템의 제어 성능을 확인할 수 있었다. 또한 열/유체적 측면과 구조적 측면을 체계적으로 고려하여 배관 시스템의 요구성능을 만족하고 발사체에서 요구되는 수준까지 무게가 저감된 배관 시스템 개발을 개발하였다. 이와 아울러 터보펌프에서의 케비테이션 방지 및 지상 대기시간동안에 배관에서 발생할 수 있는 가이저링을 방지하기 위한 액체 산소 컨디셔닝 기술을 확립할 수 있었다. 또한 가압부/산화제 공급계 연계시험을 통해 시스템 차원의 성능을 확인할 수 있었다.

• 한국임상수의학회지
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• 제11권2호
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• pp.553-560
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• 1994

This experiment was conducted to evaluate the feed value of Macol meal, which is one of the byproducts from the extraction of liquid syrup from barley grain, on lactating dairy cows. All of the lactating dairy cows feeding in eight dairy farms were used in feeding experiment and fed concentrates plus Macol meal 5Kg as wet basis. The milk yields and milk fit during the periods of 10 months were investigated and blood picture, blood chemistry and diseases occuring frequency before and after feeding Macol meal were analyzed. The results obtained were as follows ; 1. In the proximate compositions, the contents of moisture, crude protein, crude fat, crude fiber, crude as and nitrogen free extracts was 68.8%, 7.43%, 1.04%, 7.08%, 1.56% and 14.09% respectively. On the other hand, the contents of NDF, ADF and cellulose was 36.68%, 35.71% and 10.85%, as dry matter basis, respectively. 2. The daily milk yield per head was 22.84kg during two months before feeding Macol meal and 23.89 kg during the periods of ten months after feeding Macol meal. 3. The blood picture and blood chemistry were not affected by feeding Macol meal. 4. The diseases occuring frequency were not significantly affected by feeding Macol meal. from the results of this experiment it could be concluded that Macol meal can be used in lactating dairy cows rations without any adverse effects.

• Asian-Australasian Journal of Animal Sciences
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• 제16권10호
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• pp.1460-1468
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• 2003

An experiment was conducted to quantify the flow of soluble non-ammonia nitrogen (SNAN) in the liquid phase of ruminal (RD) and omasal digesta (OD), and to investigate diurnal pattern in SNAN flow in OD. Five ruminally cannulated Finnish-Ayrshire dairy cows in a $5{\times}5$ Latin square design consumed a basal diet of grass silage and barley grain, and that supplemented with four protein feeds (kg/d DM basis) as follows: skimmed milk powder (2.1), wet distiller' solubles (3.0), untreated rapeseed meal (2.1) and treated rapeseed meal (2.1). Ruminal digesta was sampled using a vacuum pump, whereas OD was collected using an omasal sampling system at 1.0 h interval during a 12 h feeding cycle. Both RD and OD were acidified, centrifuged to remove microbes and precipitated with trichloroacetic acid followed by centrifugation. The SNAN fractions (free amino acid (AA), peptide and soluble protein) in RD and OD were assessed using ninhydrin assay. Free AA, peptide and soluble protein averaged 60.0, 89.4 and 2.1 g/d, respectively, for RD, and 81.8, 121.5 and 2.5 g/d, respectively, for OD. Although free AA flow was relatively high, mean peptide flow was quantitatively the most important fraction of SNAN, indicating that degradation of peptide to AA rather than hydrolysis of soluble protein to peptide or deamination may be the most limiting step in rumen proteolysis. Diurnal pattern in flow of peptide including free AA in OD during a 12 h feeding cycle peaked 1 h post-feeding, decreased by 3 h post-feeding and was relatively constant thereafter. Protein supplementation showed higher flow of peptide including free AA immediately after feeding compared with no supplemented diet. There were no differences among protein supplements in diurnal pattern in flow of peptide including free AA in OD.

• 항공우주기술
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• 제9권2호
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• pp.168-175
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• 2010

우주발사체용 액체추진제 공급시스템에서 산화제가 엔진으로 공급될 때 다양한 환경 또는 외력에 의해서 탱크 내부의 출구영역에서 와류가 발생한다. 이러한 swirl을 방지하기 위한 탱크 내부에 AVD(Anti-Device Vortex)라는 와류방지 장치를 설치한다. 유동해석을 통해 LOX(액체산소) 공급에 효율적인 와류방지장치의 성능을 확인하였다. AVD 개수와 길이에 따라 공급시간에 대한 질유량과 산화제 자유표면에서 swirl의 크기 등을 분석해서 최적의 크기와 개수를 도출하고 설계에 반영하고자 한다.

• 한국연소학회지
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• 제4권2호
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• pp.43-50
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• 1999

Liquefied petroleum gas (LPG) has been used as motor fuel due to its low emissions and low cost. The fuel feeding system has been improved with stringent requirement for exhaust emissions. LPG carburetion system was first introduced, then the system has been changed to a precisely controlled gas injection system, but this gas feeding system has a limitation on improving power output. In order to improve an engine performance, a multi-point port injection system was introduced recently, and a liquid direct injection system into a cylinder was suggested as a next generation system to maximize a fuel economy as well as a power. This study addresses the analysis of the LPG spray from diesel injectors. The spray images are visualized and compared with diesel sprays in a wide injection pressure range. The photographs show much wider dispersion of LPG sprays.

• 한국연소학회:학술대회논문집
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• 한국연소학회 1999년도 제19회 KOSCO SYMPOSIUM 논문집
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• pp.21-26
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• 1999

Liquefied petroleum gas(LPG) has been used as motor fuel due to its low emissions and low cost. The fuel feeding system has been improved with stringent requirement for exhaust emissions. LPG carburation system was firstly introduced, then the system changed into a gas injection system controlled precisely, but those gas feeding system has a limitation on improving power output. In order to improve an engine performance, a multi-point port injection system was introduced recently, and a liquid direct injection system into a cylinder was suggested as a next generation system to maximize a fuel economy as well as a power. This study addresses the analysis of the LPG spray from diesel injectors. The spray images are visualized and compared with diesel sprays in a wide injection pressure range. The photographs show much wider dispersion of LPG sprays.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2010년도 제35회 추계학술대회논문집
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• pp.676-677
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• 2010

나로우주센터에서 2차에 걸친 나로호 발사가 수행되었다. 나로호 발사를 위한 나로우주센터 발사대는 연료 및 산화제, 고압가스 등 발사체 발사운용에 필요한 추진제 공급설비를 갖추고 있으며, 본 논문에서는 발사대 추진제 공급설비 중 극저온 추진제인 액체산소 충전시스템에 대한 개발 과정 및 운용방법에 대해 고찰한다.

• 한국자동차공학회논문집
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• 제11권4호
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• pp.7-14
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• 2003

Recently, LPG has been considered as more environmental friendly fuel than liquid fuels for vehicles. However because LPLi engine has the strong point that not only increases the volumetric efficiency and cold startability, but also decreases unburned hydrocarbon exhaust emission in warm-up condition, much attention has moved to development of the Liquid Phase LPG injection (LPLi) system from the mixer type LPG engine. To reduce exhaust NOx, this study investigated the effect of EGR with LPLi engine and determined optimized EGR feeding position and distribution. In addition, engine stability, performance, and exhaust emission level were evaluated.