• Defense and Technology
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• no.4 s.290
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• pp.18-29
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• 2003

냉전의 또 하나의 부산물은 우주경쟁인데, 인공위성 등 발사체의 추진기관은 거의 예외 없이 액체연료를 사용하는 액체추진로켓이고, 이것의 연료가 되는 액체산소, 액체수소 등은 발사체에 저장된 상태로 보관 할 수 없다는 단점 때문에 거의 군사용으로 적용되고 있지 않다. 지금은 SATURN-V와 같은 거대한 액체 추진 로켓을 대신해서 부분적으로 재활용이 가능한 우주왕복선이 사용되고 있는데, 여기에는 처음 이륙단계 대부분의 추력을 고체추진제에 의존하고 있기 때문에 이들의 성능 향상을 위한 좀 더 강역하고, 안전성을 높일 수 있는 에너지 물질에 대한 요구가 증대되고 있는 실정이다.

• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 2003.05a
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• pp.289-321
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• 2003

o연료전지 시장은 기술의 경쟁력 확보에 따라 Market Potential이 큰 사업 분야임. o연료전지 사업이 활성화되기 위해서는 경제성과 안전성의 문제 때문에 연료전지용 연료변환장치의 기술개발이 필수적임. o연료변환장치의 활용 분야에 따라 적정 연료, 적정 촉매 선정 및 열전달 효율을 극대화하는 반응기 설계 필요. o연료전지 자동차의 경우 기술의 난이도 때문에 궁극적으로는 On-board fuel processor보다 On-site fuel processor에 의한 수소 공급 station의 형태가 바람직함. o정부주도하에 조직적이고 체계적인 연구개발 필요.

• Korean Journal of Plant Tissue Culture
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• v.21 no.4
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• pp.201-206
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• 1994

The influx of glycine, valine, alanine, and histidine was inhibited by all tested neutral amino acids competitively and the reciprocal inhibitory studies showed the neutral amino acids possess the same transport system as neutral amino acids process to the same catalytic site of one carrier to each other, The molecules of histidine were transported actively as a neutral form through the neutral amino acid transport system but were not transported as a charged form. The Km values of the neutral amino acid transport system have been divided into three different category on basis of the affinity to the carrier, below 0.1mM, etween 0.1ImM-0.5mM and above 0.5mM. The $V_{max}$ was between $3.12{\mu}mole{\cdot}h^{-1}{\cdot}g$ fresh $weight^{-1}\;-\;15.1\;{\mu}mole{\cdot}h^{-1}{\cdot}g$ fresh $weight^{-1}$. Neutral amino acids cotransported with one $H^{+}per$ one molecule and one $K^{+}-efflux$ per one molecule for charge compensation. Histidine cotransported with proton per one molecule, however the movement of cotransported proton can't detectable because of the release of proton from the charged molecules of histidine in the medium.

• Transactions of the Korean hydrogen and new energy society
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• v.17 no.4
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• pp.461-469
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• 2006

This paper deals with the national competitiveness of hydrogen energy. The effectiveness of investments for hydrogen energy R&D and constructions of hydrogen energy infrastructures can be evaluated by the national competitiveness of hydrogen energy, and it is evaluated by an AHP(analytic hierarchy process) method. The evaluation indices of the national competitiveness are selected as the technical level, the number of researchers, the investments for R&D, and the infrastructure of hydrogen energy. Similarly, the technical level is divided into the number of published papers, the number of foreign patents, and the number of published proceeding papers. The evaluation indices of the technical level and the number of researchers were investigated by database searches. It appears that South Korea locates the sixth position in the world. The results of our study suggest that South Korea is relatively competitive in the technical level and the number of researchers. However, our country needs the long-term and well-focused R&D, and the expansion of infrastructures to enhance the national competitiveness of hydrogen energy in the future.

• Polymer(Korea)
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• v.32 no.6
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• pp.566-572
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• 2008

Polyethylene has been prepared via metallocene catalysts [(TMDS)$Cp_2$]$ZrCl_2$, 1, and [$(n-Bu)_2Cp_2$]$ZrCl_2$, 2, in the presence of hydrogen as a chain transfer reagent. Increase of hydrogen flow to the polymerization reactor resulted in the drop of catalytic activity, reduction of molecular weight of polyethylene, getting narrow of molecular weight distribution of polyethylene, and melting point of the polyethylene wax. It should be noticed that it was possible to control molecular weight down to 1500 and melting temperature to 60 $^\circ$C of polyethylene wax using the catalyst 1 that has been developed by authors as well as the catalyst 2 from Exxon.

• Journal of the Korea Organic Resources Recycling Association
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• v.12 no.1
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• pp.49-57
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• 2004

The effect of gas sparging on continuous fermentative $H_2$ production was investigated using external gases ($N_2$, $CO_2$) with various flow rates (100, 200, 300, 400 ml/min). Gas sparging showed a higher $H_2$ yield than no sparging, indicating that the decrease of $H_2$ partial pressure by gas sparging had a good effect on $H_2$ fermentation. Especially, $CO_2$ sparging was more effective in the reactor performance than $N_2$ sparging. The composition of butyrate, the main metabolic product of $H_2$ fermentation by Clostridium sp., was much higher in $CO_2$ sparging. $H_2$ production increased with increasing flow rate only in $CO_2$ sparging. The best performance was obtained by $CO_2$ sparging at 300 ml/min, resulting in the highest $H_2$ yield of 1.65 mol $H_2/mol$ hexoseconsumed and the maximum $H_2$ production of 6.77 L $H_2/g$ VSS/day. Compared to $N_2$ sparging, there could be another beneficial effect in $CO_2$ sparging apart from lowering down the $H_2$ partial pressure. High partial pressure of $CO_2$ had little effect on $H_2$ producing bacteria but inhibitory effect on other microorganisms like lactic acid bacteria and acetogens which were competitive with $H_2$ producing bacteria.

• Journal of Korea Society of Industrial Information Systems
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• v.9 no.4
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• pp.8-15
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• 2004

Gilding process make thin membrane with other metals to surface of metal and metalloid. It control the hydrogen ion and oxalic acid density with rinsing work since the process used to acid and alkali. Therefore, in this study, several control method applied the gilding process. It desired to the optimal controller and their results can be save on water resource by useful feed of rinsing. And there is quite a possibility of uniform production due to fixed control of acid and alkali. Also it can be contributed the competition power because of lower production unit cost. Especially, this control method to be developed can be applied to any process without mathematical model. And it can be changed their algorithm more easily, if control object is changed.

• Journal of the Korean Chemical Society
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• v.53 no.3
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• pp.368-376
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• 2009

In this study we investigated and tried to understand problems monitored in an experiment on reactivity of metals in chemistry I. Three problems were discussed. First, the reason that aluminium plate does not react with other metal ions such as zinc, iron and copper was studied and the way to overcome this problem was suggested. Second, the reason that the bubbles were generated when FeS$O_4$(aq) and Zn(s) react was discussed. Third, the precipitates which appeared in the reaction of FeS$O_4$(aq) and Zn(s) were identified. Through reference study and experimental investigation, we could reach the following results. First, aluminium could not react with other metal ions due to the surface oxide layer that is formed very fast and prevents aluminium from reacting with metal ions in solution. This problem could be overcome by allowing a competing reaction of acid and aluminium during the reaction of aluminium and metal ions. Second, the observed bubbles were identified to be hydrogen gas, produced by the reaction between metals and hydronium ion in the solution. Third, black precipitates that were produced on the surface of zinc plate and exhibited magnetic property were characterized to be $Fe_3O_4$(s), and brown precipitates that were produced in the solution phase were to be $Fe_2O_3$(s) by the analysis of X-ray photoelectron spectra.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.23 no.11
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• pp.1414-1419
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• 2019

Patent indicators were used to analyze the movements of local industries in order to derive blank technologies due to rapid changes in technology in the 4th Industrial Revolution and to discover promising technologies. Currently, Changwon-si is gathering a lot of technical information to develop hydrogen electric vehicle technology as a future regional flagship industry to discover it as a promising technology in the future. Collecting technical information has many problems in terms of time and cost due to classification methods, technical trends, and similar technologies. Therefore, a systematic classification of technical information and a method for easily deriving technical trends are needed. In this paper, we analyzed the blank technology and promising technology trends for the future core industries of the region through the method of measuring the growth rate of patents and the frequency of patent application through the patent indicators.

• 월간 기계설비
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• no.11 s.220
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• pp.29-37
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• 2008

최근들어 국제 유가가 급등하고 지구 온난화 등 환경문제가 부각되면서 기존의 에너지를 대체하는 대안으로 신재생 에너지가 전 세계적으로 뜨거운 이슈로 떠오르고 있다. 더구나 온실가스 감축 등 본격적인 환경경제 시대가 도래하면서 환경친화적이고 고갈 염려가 없는 신재생에너지가 효과적인 대안으로 주목받고 있다. 또한 고유가 및 기술개발 가속화도 신재성에너지 시장 확대를 부채질하고 있어 신재생에너지에 대한 관심이 신성장동력으로 집중되고 있다. 이처럼 환경문제 해결에 대한 관심은 '선택'이 아닌 '필수'가 되었다. 우리나라도 국가 차원에서 이산화탄소 배출을 줄이기 위해 '저탄소 녹색성장' 정책을 마련하면서 신재생에너지 확대 보급을 위한 제도 및 대책이 새롭게 마련되고 있다. 건설산업은 대표적인 에너지 다소비업종에 속하기 때문에 이산화탄소 저감을 위해 에너지 저소비형 건축물 연구에 많은 투자를 하고 있으며, 신재생에너지를 이용한 생태토시 조성 등에 노력을 기울이고 있다. 특히 에너지를 다루는 기계설비는 이러한 신재생에너지와 밀접한 관련이 있기에 더욱 관심을 기울이고 있다. 태앙광을 비롯하며 지열, 풍력, 바이오 등 신재생에너지 개발은 물론 빗물이용 시스템 쓰레기 이송 설비와 같은 첨단과 환경이 조화를 이루는 아파트의 보급도 차츰 늘어나고 있는 추세다. '누구의 영역도 아닌' 곳이자 '누구의 영역도 될 수 있는' 신재생에너지가 설비건설업계에 확대, 보급되기 위해서는 설비건설업계의 관심이 집중되어야하며, 기술개발을 활발히 하여 선점경쟁에서 유리 한 고지를 접할 수 있을 것이다. 그렇다면 국내 신재생에너지의 개발 수준은 어디까지 왔을까? 이번 호는 그 현황을 집중 조명해 보고, 다음 호에는 풍력, 바이오에너지, 지열, 연료전자 수소 등을 하나씩 분석해 본다.