촉매반응에 의한 연탄 연소가스로부터 일산화탄소의 제거 (제1보)

정기호,이원국,Chung Ki Ho,Lee, Won Kook Korean Chemical Society 1976 대한화학회지 Vol.20 No.5

연탄 연소가스중의 일산화탄소와 산소 사이의 반응을 몇가지 촉매에 대해 조사했다. 이산화망간, 산화 동 및 그 혼합촉매를 사용하였으며, 그 실효반응 온도(effective reaction temperature)는 각각 다음과 같다. 즉, $MnO_2$ 단독촉매 및 30% $MnO_2$-70% CuO 혼합촉매는 $250^{\circ}C,\;CuO$는 $450^{\circ}C$, 50% $MnO_2$-50% CuO는$200^{\circ}C$, 70% $MnO_2$-30% CuO는$180^{\circ}C$였다. 실효반응온도 이하에서 일산화탄소의 산화율은 일산화 탄소의 농도가 증가함에 따라 감소하는 경향을 보였으며, 실효반응 온도 이상에서는 변화가 없었다. 반응기 내 체재시간은 0.9 ∼ 1.8초의 범위 내에서는 일산화탄소 산화반응에 조금도 영향을 주지 않았다. On the condition of adequate air supply, complete removal of carbon monoxide,occurred above $650^{\circ}C$. Using catalysts, the oxidation of carbon monoxide occurred at lower temperatures; on both $MnO_2 \;and\;30%\;MnO_2-70%\;CuO\;at\;250{\circ}C,\;on\;CuO\;at\;450{\circ}C,\;on\;50%\;MnO_2-50%\;CuO\;at\;200{\circ}C,\;and\;on\;70%\;MnO_2-30%\;CuO\;at\;180{\circ}C$. Manganese dioxide (p-type) showed higher activity than cupric oxide (n-type) and a catalyst consisting of 60% $MnO_2-40%$ CuO had the highest activity of all the $MnO_2$-CuO mixture. Over the range of transitional temperature, carbon monoxide removal efficiency decreased linearly with increasing inlet carbon monoxide concentration while temperature was fixed. Residence time of gases in the catalytic reactor, in the range of 0.9 to 1.8 seconds, gave no effect on carbon monoxide conversion.

국내 기업의 CPFR 도입 환경에 관한 고찰

정기호(Ki Ho Chung),한창엽(Chang Yup Han) 한국SCM학회 2004 한국SCM학회지 Vol.4 No.1

비용과 리드타임을 고려한 3단계 공급사슬 네트워크 최적 설계에 관한 연구

정기호(Ki Ho Chung) 한국SCM학회 2014 한국SCM학회지 Vol.14 No.1

This paper deals with the problem of designing 3-stage supply chain network consisting of suppliers, plants, distribution centers(DCs) and retailers. To define the problem considered in this paper it is assumed that there are single product, multiple raw materials, and two objective functions and there exists a lead time for DCs to replenish the order from retailers. The problem determines the locations and numbers of plants and DCs to be open among the potential plants and DCs, and allocates the raw materials from suppliers to open plants and finished goods from plants to DCs and from DCs to retailers while minimizing total costs as well as maximizing the customer service levels. This paper formulates the mathematical model for this problem and develops the solution procedure exploiting the fuzzy set theory. In order to show the applicability of the proposed solution procedure five different sized numerical examples are generated and solved.

컨테이너 수송차량의 할당 및 스케쥴링을 위한 모델

정기호 ( Ki Ho Chung ),고창성 ( Chang Seong Ko ),신재영 ( Jae Young Shin ) 한국로지스틱스학회 2005 로지스틱스연구 Vol.13 No.1

한국기업의 공급사슬관리 전략의 적합성에 관한 실증연구

정기호(Ki Ho Chung),손승호(Seung Ho Son),정동섭(Dong Seop Chung) 한국경영학회 2005 經營學硏究 Vol.34 No.1

Today's business environment has become rapidly changed. The development of internet and information technology makes customer needs more segmented and increases customer's demand for product variety and then customers require higher level of customization than ever. Moreover globalization in procurement, manufacturing and distribution makes lead time increasing and product life cycles have become shorter, while customers want products to be quickly supplied at lower price. Under these business environments, managing supply chain effectively is very important for firms to differentiate products and services and to achieve their competitive advantages. The importance of supply chain management(SCM) has been emphasized and there have been many researches on SCM or SCM-related topics. Each product has different product life cycle, demand uncertainty and product variety from others. So many researchers pointed out that since the characteristics of products and customer needs are different according to the product, supply chain performance is improved only when supply chain is designed appropriately to the characteristics of products and customer needs. Since successful SCM depends on how well supply chain strategies are aligned with the characteristics of products and customer needs, strategic fit of SCM has emerged as an important issue in managing supply chains. However there has been no research on empirical analysis for the relationship between supply chain performance and strategic fit of SCM. This paper empirically analyzed whether there exists a difference in supply chain performances according to the extent of strategic fit between implied demand uncertainty and SCM strategies. As in previous researches we translate characteristics of products and customer needs into the metric of implied demand uncertainty and represent SCM strategies as tradeoff between responsiveness and efficiency.We developed two main hypotheses; one is that there exists a difference in supply chain performance according to the extent of strategic fit between implied demand uncertainty and SCM strategy and the other is that for each subgroup with different level of implied demand uncertainty there exist differences in supply chain performance according to the extent of strategic fit. To test the proposed hypotheses, survey data were collected from 122 Korean manufacturing firms and analyzed with factor analysis and clustering analysis. The factors are examined on the basis of preceding researches, and extensible factors are clearly extracted from the literature review. Furthermore, the determinants of a SCM strategy are drawn through a detailed cluster analysis framework.The results of analysis showed that there existed a significant difference in supply chain performances between two groups; group achieving high level of strategic fit and group achieving low level of strategic fit. Interestingly, the difference in supply chain performances was also found within the group achieving high level of strategic fit; that is, the subgroup having high responsive supply chain with high implied demand uncertainty showed higher performance than the subgroup having low responsive supply chain with low implied demand uncertainty. These results imply that i) to achieve the strategic fit, firms should change their supply chain strategies if the characteristics of products and/or customers are changed, and ii) even though the strategic fits are achieved, supply chain of the innovative product has higher performance than the functional product. As a result, this research strongly suggests that companies should employ a right supply chain strategy according to their product attributes and supply chain environments.

자동차부품산업의 수요 및 공급불확실성과 공급사슬 유형의 적합성에 관한 연구

정기호(Ki Ho Chung) 한국SCM학회 2007 한국SCM학회지 Vol.7 No.1

구연산을 함유한 시판 차음료가 치아 표면에 미치는 영향

정기호 ( Ki-ho Chung ) 대한예방치과·구강보건학회 2017 大韓口腔保健學會誌 Vol.41 No.3

Objectives: The purpose of this study was to evaluate the erosive potential of tea beverages containing citric acid on tooth surfaces. Methods: Specimens of extracted bovine teeth enamel were embedded in resin and polished. The specimens were subjected to one of three treatments (n=10 per treatment group): mineral water, brewed black tea, or black tea beverage. Tooth specimens were exposed to the treatment for 30 minutes and then analyzed using Vickers surface hardness testing and scanning electron microscopy. Results: After 30 minutes of treatment, there were statistically significant differences between the hardness of the enamel pre- and post-treatment in both, the brewed black tea and black tea beverage groups (P<0.05). The differences in microhardness (△VHN) were ―71.49±14.99, ―9.05±10.25, and ―2.43±15.44 in the black tea beverage, brewed black tea, and mineral water groups, respectively. In the difference of microhardness (△VHN) between groups, the black tea beverage group showed significantly greater changes than the brewed black tea and mineral water groups (P< 0.05). However, there was no significant difference between the brewed black tea group and the mineral water group (P >0.05).On observation using a scanning electron microscope, the tooth surfaces exposed to the black tea beverage containing citric acid were rougher than the tooth surfaces in the other two groups. Conclusions: This study demonstrates the erosive potential of citric acid-containing tea beverages on tooth surfaces. Thus, there is need to caution people regularly consuming tea beverages containing citric acid, regarding the possibility of tooth surface erosion.

택배산업의 효율적 공동수배송을 위한 수리적 모형 개발에 관한 연구

정기호 ( Ki Ho Chung ),정원재 ( Won Jae Jeong ) 한국물류학회 2008 물류학회지 Vol.18 No.2

특별강연발표초록 : 광섬유 소재의 개발 및 현황

정기호 (정)( Ki Ho Chung ) 한국화학공학회 1984 춘계총회초록집 Vol.- No.-

해운산업 전략적 제휴를 위한 슬롯교환모형

정기호(Ki Ho Chung) 한국SCM학회 2018 한국SCM학회지 Vol.18 No.2

Since the mid-2000s, the global shipping industry has been unable to escape from the vicious circle of the long-term depression. In order to get rid of the vicious cycle of shipping industry, shipping companies around the world are avoiding excessive competition and plans to cooperate to reduce costs. The most widely used method among these alliances is the slot exchange method. Using the slot exchange method can reduce the competition and increase profitability by increasing the utilization rate of the vessels. As a result, it is possible to reduce the cost and increase the profit of the affiliated companies. It is important to pursue maximizing profits or minimizing costs from the perspective of all affiliates, rather than attempting to maximize the benefits of each other. Recently, several studies have been made to apply optimization technique using mathematical model of slot exchange method. However, the researches so far have limited the practical application because they deal with only the alliance model between two companies due to the complexity of the problem. The purpose of this study is to develop a mathematical model for three or more affiliated companies and to apply the problem to the sample in order to find out the applicability of the problem. And this study also proposes how to distribute the cost reduction effect of partnership rationally among the affiliated companies using the Shapley value.