• The Bulletin of The Korean Astronomical Society
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• v.37 no.2
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• pp.152.2-152.2
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• 2012

우주발사체 발사를 위해서는 발사대시스템 개발이 필수적이다. 발사대시스템은 기계설비와 추진제공급설비, 관제설비로 구성되며, 그 중 기계설비는 발사지지대(Launch Pad), 이렉터(Erector), 트랜스포터이렉터(Transport-Erector), 케이블마스트(Cable-mast), 자동체결장치(Auto-coupling Device) 총 다섯 부분으로 나눌 수 있다. 발사지지대는 발사 전까지 발사체를 지지하는 구조물로 발사체의 안전을 보장하고 공급배관 및 통신라인의 경로를 제공한다. 이렉터는 발사준비과정에서 수평으로 이송된 발사체를 2개의 대형 유압실린더를 사용하여 기립시키는 장비로 발사 취소 시 발사체를 수평으로 전환한다. 트랜스포터이렉터는 조립공간에서 조립을 마치고 최종점검이 완료된 발사체를 전용차량을 이용하여 발사대로 이동하고 발사체를 안전하게 잡아준다. 자동체결장치는 지상으로부터 발사체로 연결되는 추진제, 압축가스 등의 연결배관을 자동으로 연결/분리하는 장치이다. 케이블마스트는 우주발사체 상단부의 UCU-E(Umbilical Connectors Unit-Electrical)를 통해서 전기, 고압가스, 고온공기 등을 공급하기 위한 통로로 발사 전까지 발사체시스템과 지상장비와의 통신수단이다. 또한 발사체로 연결되는 라인들을 발사 시에 나오는 후류에 의한 충격으로부터 보호하고, UCU-E가 기계적으로 분리되도록 구성되어 있다. 본 논문은 기존에 적용된 케이블마스트에 대한 구성, 기능 및 운용절차에 관한 것으로, 현재 진행 중인 한국형발사체 개발을 위한 기초 자료조사로 활용하고자 한다.

• Journal of Practical Agriculture & Fisheries Research
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• v.11 no.1
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• pp.183-195
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• 2009

시설하우스의 공기환경은 작물생육에 큰 영향을 준다. 특히 기공주변 공기의 상대습도는 증산작용에 크게 영향을 주며, 안개가 끼게 되면 기공을 통한 증산작용이 일어나지 않아 작물은 생육을 멈추게 된다. 이에 대한 이론적 고찰을 습공기선도를 중심으로 살펴보았으며, 그 기술을 권왕림(경기도 이천시 백사면 모전2리 192) 쌈채소 재배 농장과 정기설(경기도 용인시 백암면 석천리) 백암육계 농장에 적용한 결과를 요약하면 다음과 같다. 1. 여름철 온실 공기의 온도를 낮추기 위하여 널리 사용하는 Pad & Fan, Mist & Fan 등의 증발냉각 방법은 사막 기후지역(온도는 높고 습도는 낮은 지역)에 적합한 방법으로 우리나라와 같이 고온 다습한 기후에는 적합하지 않다. 2. 겨울철 저녁에 온실을 보온하기 전에 따뜻한 공기의 열이 연료비를 절감 할 수 있다는 생각으로 환기를 하지 않으면 절대습도가 높아 약간의 온도가 떨어져도 안개가 발생하게 된다. 3. 겨울철 저녁에 온실을 보온하기 전에 외부 공기로 충분히 환기하여 절대습도를 낮추면 노점온도가 낮아지고, 약간의 난방으로도 온실의 안개를 방지할 수 있다. 4. 여름철 상추재배에서 시원한 바람으로 공기환경을 개선한 결과 41.6%의 증수효과가 있었다. 5. 겨울철 육계농장의 공기환경 개선으로 47,300수 기준으로 폐사율 2%와 난방연료 40%를 절감할 수 있었으며, 육계 성장의 균일도를 53%→73%로 20%정도 높일 수 있었다. ※ 정기설 백암육계 농장(경기도 용인시 백암면 석천리) (011-719-7597)

• Korean Journal of Microbiology
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• v.51 no.3
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• pp.221-230
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• 2015

Ground bed cultivation method for shiitake mushroom (Phogo; Lentinula edodes) has been advanced to use the oak-sawdust composted by microorganisms. This method has some advantages in saving the labors and improving productivity. The aim of this study is to analyze microbial community in oak sawdust and to provide the information for efficient cultivation of shiitake mushroom. In process of composting, the proportions of thermophiles increased from 10% to 80%. This results show the microbial community succession from mesophilic bacteria to thermophilic bacteria. T-RFLP analysis and nucleotide sequencing of 16S rRNA gene demonstrated that the change of dominant bacteria coupled with shifts in each stages. The family of Enterobacteriaceae as a mesophilic bacteria were dominant (100%) in oak sawdust sample, but Amycolatopsis (49.0%) and Saccharopolyspora (26.5%) as a thermophilic Actinomycetes were dominant in the last day of composting. In hyphal growth stage, Leuconostoc (psychrophilic bacteria) was dominant (75.0%). The composting process of sawdust is very important for growth of mushroom mycelium. Therefore, there is need for the further study for the Amycolatopsis as thermophilic Actinomycetes.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.30 no.3
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• pp.223-228
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• 1985

Photosynthetic inhibition to temperature were conducted with ginseng(4 year old) and tobacco(var. Bulgaria). The plants were kept under various temperature conditions from 1$0^{\circ}C$ to 4$0^{\circ}C$ and 440$\mu$E/$m^2$/sec for 3 and 6hrs, and net $CO_2$ uptake were measured after 2hrs at $25^{\circ}C$. Photosynthetic optimal leaf temperature of ginseng was 21$^{\circ}C$ and tobacco was $25^{\circ}C$. Stomatal resistance and mesophyll resistance increased at high temperature. Especially, stomatal resistance seemed to have a significant role in determining the temperature responses of photosynthesis. In tobacco photosynthetic capacity was not changed by temperature treatment for 3hrs. However, 6hrs exposure reduced 8% of net photosynthesis at 4$0^{\circ}C$ and 12% at 1$0^{\circ}C$. Ginseng plants exposed for 6hrs at 4$0^{\circ}C$ lost photosynthetic capacity by 83%. Temperature responses of ginseng were very sensitive at above-optimum temperature resulting greater thermal inhibition other than photoinhibition.

• Horticultural Science & Technology
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• v.34 no.5
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• pp.719-726
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• 2016

The effect of high and low temperatures on seedling quality while raising of paprika (Capsicum annuum L.) seedlings, and their early development after planting was investigated. The control raising seedling temperature (RST) was $23^{\circ}C$; high temperature, $31^{\circ}C$; and low temperature, $15^{\circ}C$ throughout the raising seedling period. At $15^{\circ}C$ and $30^{\circ}C$, plant height, stem diameter, fresh weight, dry weight, number of leaves, and seedling leaf area were significantly lower than those at $23^{\circ}C$. At 4 weeks after planting, seedling's growth characteristics showed a similar pattern. Compared to $23^{\circ}C$, seedlings raised at $15^{\circ}C$ and $30^{\circ}C$ had an increased dry weight and leaf area per unit time after planting than during the seedling raising period. At 4 weeks after planting, crop growth rate and leaf area index were unaffected by RST, and relative growth rate and net assimilation rate at RSTs of $15^{\circ}C$ and $31^{\circ}C$ were higher than those those at RST of $23^{\circ}C$. At an RST of $15^{\circ}C$, growth speed and net assimilation rates were higher after planting than before planting, according to increased photosynthetic rate. Thus, high and low temperatures during the seedling raising period significantly reduced seedling growth and plant growth after planting. After planting, seedlings raised at $15^{\circ}C$ recovered more quickly than did those raised at $31^{\circ}C$.

• Korean Journal of Poultry Science
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• v.6 no.1
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• pp.24-30
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• 1979

1. The effects of heat stress (38$^{\circ}C$), cold stress (4$^{\circ}C$) and extreme cold stress (-20$^{\circ}C$) before slaughter on the tenderness and postmortem glycolysis if the excised chicken breast muscle were studied Heat stress significantly (p 0.05) increased the toughness of breast muscle. Though statistically not significant, cold stress also adversely affected the tenderness. The heat-stressed birds showed higher zero hr glycogen higher zero hr pH and significantly (p 0.05) love. ultimate pH then the controls. The cold-stressed birds showed intermediate values in these parameters. Highly significant correlations. were observed between shear value and each of these three parameters. Glycolysis rate ana final moisture content were minor factors which affected the muscle tenderness to a limited extent. The slightly elevated lactate-dehydrogenase and creatine phosphokinase activities in serum and breast muscle of stressed birds failed to account for any variations in tenderness. 2. Chicken breast and thigh muscles were subjected to different environmental temperatures to determine if the phenomenon of cold shortening exists in chicken muscle. For both breast and thigh muscles, minimum shortening was observed in the 4-10$^{\circ}C$t range. Muscles held at 0$^{\circ}C$ showed a slightly higher extent of shortening than at 4$^{\circ}C$; where as muscles held at above 20$^{\circ}C$ showed a severe shortening effect. It was concluded that no apparent cold shortening was detected in chicken muscle except at 0$^{\circ}C$ and even at 0$^{\circ}C$ and even at 0$^{\circ}C$ the extent of shortening was of a small magnitude compared to bovine muscles. Since high temperature induces a much greater shortening, muscle temperature must be lowered to below 20$^{\circ}C$ as early as possible to prevent excessive muse]e shortening.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.35 no.11
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• pp.1499-1506
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• 2011

The IHX (intermediate heat exchanger) is a key component of nuclear hydrogen systems for the production of massive amounts hydrogen. The IHX transfers the $950^{\circ}C$ heat generated by the VHTR (very high temperature reactor) to a hydrogen production plant. The Korea Atomic Energy Research Institute established a small-scale gas loop to test the performance of key VHTR components and manufactured a small-scale PCHE (printed circuit heat exchanger) prototype, which is being considered as a candidate for the IHX, for testing in the small-scale gas loop. In this study, as a part of the high-temperature structural integrity evaluation of the small-scale PCHE prototype, we carried out high-temperature structural analysis modeling and macroscopic thermal and structural analysis for the small-scale PCHE prototype under the small-scale gas loop test conditions. This analysis serves as a precedent study to scheduled PCHE performance test in the small-scale gas loop. The results obtained in this study will be compared with the test results for the small-scale PCHE and then used to design the medium-scale PCHE prototype.

• Korean Journal of Agricultural Science
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• v.22 no.2
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• pp.134-142
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• 1995

In order to elevate the efficiency of methane fermentation using the paper mill sludge, this experiment was conducted at two temperature conditions($35^{\circ}C$ and $60^{\circ}C$), and overlooked the addition effects of ethyl acetate as a substrate, nickel as a constituent of $F_430$, and sulfur as a cell growth factor and reductant. The cellulose of paper mill sludge was degraded to lower molecular materials by heating at $60^{\circ}C$ and NaOH treatment. Methane forming rates were 4.8% from NaOH-treated paper mill sludge added with ethyl acetate, 16.5% with sodium sulfide, 19.8% with nickel trioxide, 31.9% with mixture, and 9.6% with control at $60^{\circ}C$, but 0.21% with ethyl acetate, 2.14% with nickel acetate, 3.02% with nickel sulfate, 3.34% with nickel trioxide and 0.62% with control at $35^{\circ}C$. Therefore, methane yield was increased by approximately 10-fold at $60^{\circ}C$ than $35^{\circ}C$, and fermentation liquid added with mixture(nickel trioxide+ethyl acetate+sodium sulfide) at $60^{\circ}C$ showed the medium pH(7.0), higher COD value and lower nitrogen content.

• Journal of the Korean Institute of Gas
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• v.19 no.5
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• pp.69-74
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• 2015

The study investigated numerically the heat transfer and chemical reaction characteristics of a methane-steam reforming by using a 3-dimensional computational fluid dynamics (CFD) code (Fluent ver. 16.1). The fuel temperature and its species mole fractions were estimated for various Reynolds number in the reformer tube at different burner temperatures. The catalysts were modeled as the porous medium of nicrome in the reformer tube. We considered radiation effect as well as conduction and convective heat transfer because the methane-steam was reformed at very high temperature condition above 1000 K. For two different Reynolds numbers of 49,000 and 88,000 and the burner temperatures were in the range from 1,100 K to 1,300 K. At a low Reynolds number, the fuel temperature increased, leading to increase in hydrogen reforming. However, fuel temperature and hydrogen reforming decreased because of higher convective heat transfer from relatively low fuel temperature. Moreover, the hydrogen reforming also increased with burner temperature.

• 한국해양학회지
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• v.22 no.2
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• pp.57-62
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• 1987

The Markov chain properties of the sea surface temperature (SST) anomalies, namely, the dependency of the monthly SST anomaly on that of the previous month, are studied based on the SST data for 28years(1957-1984) at 5 stations in the southeastern coast of Korea. Wi classified the monthly SST anomalies at each station into the low, the normal and the high state, and computed transition probabilities between SST anomalies of two successive months The standard deviation of SST anomalies at each station is used as a reference for the classification of SST anomalies into 3states. The transition probability of the normal state to remain in the same state is about 0.8. The transition probability of the high or the low states to remain in the same state is about one half. The SST anomalies have almost no probability to transit from the high (the low) state to the low (the high) state. Statistical tests show that the Markov chain properties of SST anomalies are stationary in tine and homogeneous in space. The multi-step Markov chain analysis shows that the 'memory' of the SST anomalies at the coastal stations remains about 3 months.