• Electric Engineers Magazine
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• v.246 no.2
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• pp.30-33
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• 2003

증발성 액체소화제 할로겐화 탄화수소는 기화되기 쉬운 액체 또는 기체이고 억제작용, 희석효과, 기화열에 의한 냉각 등 3가지의 작용을 한다. 액상인 것은 목재화재에도 다소 쓰이고 있지만 가연성약제의 소화에 쓰일 뿐만 아니라 전기의 불량도체이므로 전기화재에 대한 적응성이 있다.

• Journal of the Korean Society of Propulsion Engineers
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• v.8 no.3
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• pp.61-67
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• 2004

The extinction characteristics of the solid propellant were studied experimentally in this paper. These characteristics are required for designing TCO (thrust cut off) system of the solid rocket motor Parameters to characterize solid propellant extinction were defined by physical observation. A device was designed (or acquiring these parameters and the firing tests were implemented to get the preliminary data for the extinction characteristics of HTBP propellant.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.11a
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• pp.464-466
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• 2011

This technical paper presents a new solid propellants family. The views are based on open literature and patents recently. Electrically controlled extinguishable solid propellants (ESCSP) are capable of multiple ignitions, extinguishments and throttle control by the application of electrical power. Both core and end burning no moving parts ECESP grains/motors to three inches in diameter have now been tested. Ongoing research has led to a newer family of even higher performance ECESP providing up to 10% higher Isp, manufacturing ease, and significantly higher electrical conduction.

• Journal of Animal Science and Technology
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• v.49 no.3
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• pp.341-350
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• 2007

The present study was conducted to measure diurnal patterns in the flow of soluble non-ammonia nitrogen (SNAN) fractions in the liquid phase of digesta entering the omasum of cows fed grass-red clover silage supplemented with barley and rapeseed meal. Four ruminally cannulated cows were fed, in a 4×4 Latin square design, grass-red clover silage alone (GS) or supplemented with (on a DM basis) 6.0kg/d of barley grain, 2.1kg/d of rapeseed meal or 6.0kg/d of barley and 2.1kg/d rapeseed meal. Omasal digesta was taken using an omasal sampling system at 1.5h intervals during a 12h feeding cycle, and SNAN fractions (free AA, peptide and soluble protein) in the omasal digesta were assessed using ninhydrin assay. Dietary supplementation numerically increased the mean flow of SNAN fractions relative to GS diet despite the lack of statistical significance. Diurnal patterns in the flow of peptide entering the omasum during a 12h feeding cycle appeared to be highest immediately after feeding, declined by 10.0h post-feeding and slightly increased thereafter. In SNAN fractions, the flow of peptide was higher for supplemented diets than for GS diet throughout the feeding cycle. Based on the microbial contribution to total SNAN using 15N, diurnal patterns in the flow of dietary SNAN for dietary supplemented diets appeared to be higher compared with GS diets. Present results may conclude that peptide flow is quantitatively the most important N in SNAN fractions and that dietary supplementation can increase peptide flow entering the omasal canal.

• Proceedings of the Korean DIstribution Association Conference
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• 2000.10a
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• pp.151-162
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• 2000

철도소화물 부문의 택배시스템 도입은 원가절감이 가능하고, 경쟁력을 갖출 수 있는 장점을 갖추고 있으므로, 현실적으로 매우 필요하다. 택배시스템 도입은 철도청에서 제3자에게 위탁 운영케 하든지, 직접 운영하든지, 별도법인을 만들 수도 있다. 그러나 본고에서는 이러한 내용은 별도의 연구가 있어야할 것으로 보이므로 생략한다. 본고에서는 환경ㆍ제도적인 측면과 운영ㆍ시스템 측면에서 택배시스템을 도입하기 위한 대책방안 만을 강구한다. 본고는 철도소화물시장이 독점적으로 정부의 관할 하에 있기 때문에 철도소화물에 대한 연구가 국내에서 여러 전문가에 의하여 다양하게 전개되지 못하였다는 점이 취약점이다. 따라서 본고도 이러한 환경에서 폭넓은 연구사례를 제기하지 못한다는 한계가 있다. 그러나 설문조사나 인터뷰, 실증자료와 관련 기업과 단체의 내부자료를 통하여 이 문제를 극복하고자 노력하였다.

• Fire Science and Engineering
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• v.16 no.1
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• pp.1-7
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• 2002

Halogen-based fire suppressing agents have environmental problems because they cause the stratospheric ozone depletion and globe warming. Hence, fire suppression system using fine water mist became the center of interest as a substitution of halon. As a study about this, it is in progress to make the optimum droplet size by using water mist nozzles and to improve the extinguishing performance of water mist by using additives. Before this study, the extinguishing time of ethanol and n-heptane pool fire was measured with changing of water mist droplet size, flow density, discharge pressure, and fire size. In this study, on adding the additives to improve physical and chemical extinguishing performance of water mist, the extinguishing performance would evaluate and the optimum condition would find out. As a result, in case of ethanol pan 1 pool fire, the extinguishing time of the water mist by adding of 2.5 wt% NaCl and 0.3% AFFF got shorter 27% and 60% than the pure water mist. Adding of AFFF was to decrease the flame temperature by forming thin film on the fuel surface and to decrease the evaporation of n-heptane fuel. In case of NaCl, alkali salt crystals showed on the flame surface.

• Korean Journal of Environmental Biology
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• v.17 no.2
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• pp.129-138
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• 1999

Chlorinated aromatic compounds are one of the largest groups of environmental pollutants as a result of world-wide distribution by using them as herbicides, insecticides, fungicides, solvents, hydraulic and heat transfer fluids, plasticizers, and intermediates for chemical synthesis. Because of their toxicity, persistence, and bioaccumulation, the compounds contaminated ubiquitously in the biosphere has attracted public concerns in terms of serious influences to wild lives and a human being, such as carcinogenicity, mutagenicity, and disturbance in endocrine systems. The biological recalcitrance of the compounds is caused by the number, type, and position of the chlorine substituents as well as by their aromatic structures. In general, the carbon-halogen bonds increase the recalcitrance by increasing electronegativity of the substituent, so that the dechlorination of the compounds is focused as an important mechanism for biodegradation of chlorinated aromatics, along with the cleavage of aromatic rings. The removal of the chlorine substituents has been known as a key step for degradation of chlorinated aromatic compounds under aerobic condition. This can occur as an initial step via oxygenolytic, reductive, and hydrolytic mechanisms. The studies on the biochemistry and genetics about microbial dechlorination give us the potential informations for microbial degradation of xenobiotics contaminated in natural microcosms. Such investigations might provide biotechnological approaches to solve the environmental contamination, such as designing effective bioremediation systems using genetically engineered microorganisms.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2006.04a
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• pp.198-202
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• 2006

국내의 대표적인 지하수 오염물질인 trichloroethylene(TCE)을 반응벽체의 일종인 영가철을 이용하여 처리할 때 계면활성제가 미치는 영향을 다양한 계면활성제를 이용하여 조사하였다. 비이온성 계면활성제와 음이온성 계면활성제는 TCE의 탈염소화 반응속도는 감소시켰으나 양이온성 계면활성제는 임계미셀농도 (CMC) 미만에서는 반응속도를 증가시켰으나, CMC 이상의 농도에서는 반응속도를 감소시켰다. 양이온성 계면활성제는 TCE의 철 표면 흡착을 증가시켜, 철 표면에서 일어나는 TCE의 탈염소화 반응속도를 증가시키는 것으로 사료된다.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.65 no.4
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• pp.508-517
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• 2020

This study aimed to determine the minimum period of aeration treatment of co-digestate to develop it as liquid fertilizer and the chemical changes that occur in the aerobic liquefying process. The co-digestates were divided into three types depending on their additives: swine slurry anaerobic digestate (SS AD), swine slurry 70% + cow slurry 30% anaerobic digestate (SS + CS AD), and swine slurry 70% + apple pomace 30% anaerobic digestate (SS + AP AD). The pH of all co-digestates increased rapidly after 3 days of aerobic treatment, but had slightly decreased in SS AD after 9 days and in SS + CS AD and SS + AP AD after 15 days. All co-digestates showed a strongly reduced pH between 27 and 36 days of aeration treatment. SS AD had lower pH value, dissolved oxygen (DO), NH₄-N, and NO₃-N content under aerobic conditions than other co-digestates. To assess the fully decomposed liquid fertilizer, a germination test was performed on the undiluted and diluted co-digestate using the liquid fertilizer germination index (LFGI) method. The relative germination ratio, relative root elongation, and germination index of SS AD were higher than those of the others. When the LFGI method was used for the germination test, all co-digestates showed an appropriate germination index of 70 after 60 days of aeration treatment. Thus, we suggest that the minimum period of aeration treatment for co-digestates might be 60 days to develop the fully decomposed liquid fertilizer.

• 건강소식
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• v.35 no.6
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• pp.16-17
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• 2011

음식물을 받아들여 소화하는 위장. 최대 1,500ml 정도까지 커지는 위장은 식도와 연결된 분문으로 음식물을 받아 소화시키고 잠시 저장한 뒤 유문을 통해 십이지장으로 내려보낸다. 중요한 역할을 하는 만큼 이상이 생기면 소화 불량, 더부룩함, 배탈, 속 쓰림, 설사 등 여러 증상으로 SOS신호를 보내는데, 이 같은 경고를 쉽게 무시해 버리는 게 문제다. 특히 위암은 조기에 발견하면 90% 이상 완치될 수 있으므로 정기적으로 위장을 검사해야 한다. 내시경을 넣는 위내시경검사, 조영제를 마시고 X선 촬영을 진행하는 조영촬영검사가 대표적이다.