• Nuclear Engineering and Technology
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• 제39권1호
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• pp.1-8
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• 2007

Hydrogen and electricity are expected to dominate the world energy system in the long term. The world currently consumes about 50 million metric tons of hydrogen per year, with the bulk of it being consumed by the chemical and refining industries. The demand for hydrogen is expected to increase, especially if the U.S. and other countries shift their energy usage towards a hydrogen economy, with hydrogen consumed as an energy commodity by the transportation, residential and commercial sectors. However, there is strong motivation to not use fossil fuels in the future as a feedstock for hydrogen production, because the greenhouse gas carbon dioxide is a byproduct and fossil fuel prices are expected to increase significantly. An advanced reactor technology receiving considerable international interest for both electricity and hydrogen production, is the modular helium reactor (MHR), which is a passively safe concept that has evolved from earlier high-temperature gas-cooled reactor (HTGR) designs. For hydrogen production, this concept is referred to as the H2-MHR. Two different hydrogen production technologies are being investigated for the H2-MHR; an advanced sulfur-iodine (SI) thermochemical water splitting process and high-temperature electrolysis (HTE). This paper describes pre-conceptual design descriptions and economic evaluations of full-scale, nth-of-a-kind SI-Based and HTE-Based H2-MHR plants. Hydrogen production costs for both types of plants are estimated to be approximately $2 per kilogram.

• 한국품질경영학회:학술대회논문집
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• 한국품질경영학회 2007년도 춘계학술대회
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• pp.187-195
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• 2007

최근 우리나라에서 도요타를 벤치마킹하여 TPS를 도입하는 회사가 늘어나고 있다. 다품종 소량생산의 Lean 생산방식을 적용하기 위해서는 셋업시간의 단축 뿐만 아니라 이에 따른 셋업 품질능력이 향상되어야 한다. 따라서, 공정을 셋업하는 작업자들에게 이러한 Complex Target & Control Chart를 적용한다면, 통계적인 지식 없이도 공정의 불량을 예방 할 수 있으리라 확신한다. 이러한 관리도를 사용하여 공정능력을 향상한다면, 일본과 같은 높은 수준의 공정능력을 확보 할 수 있을 것이다. 단, 본 관리도는 현장 작업자를 위한 불량예방을 위한 품질관리 도구이며, 공정변동을 관리하기 위해서는 엔지니어 측면에서 관리도의 활용도 병행되어야 한다.

• Journal of Periodontal and Implant Science
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• 제38권3호
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• pp.511-520
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• 2008

Purpose: Diabetes mellitus is a clinically and genetically heterogeneous group of metabolic disorders manifested by abnormally high levels of glucose in the blood. Mounting evidence demonstrates that diabetes is a risk factor for gingivitis and periodontitis. The circulating mononuclear phagocytes in diabetic patients with hyperglycemia are chronically exposed to high level of serum glucose. Thus, this study attempted to determine the effect of pre-exposure of monocytes and macrophages to high concentration of glucose on lipopolysaccharide (LPS)-induced production of pro-inflammatory mediators. Material and Methods: For this purpose, cells were cultured in medium containing normal (5 mM) or high glucose (25 mM) for 4-5 weeks before treatment for 24 h with LPS. LPS was highly purified from Porphyromonas gingivalis or Prevotella intermedia by phenol extraction. Result: Results showed that prolonged pre-exposure of cells to high glucose markedly increased LPS-stimulated NO secretion when compared to normal glucose. In addition to NO, high glucose also augmented LPS-stimulated IL-6, IL-8, and TNF-$\alpha$ secretion after cells were exposed to high glucose for 4 weeks. Conclusion: The present study demonstrates that pre-exposure of mononuclear phagocytes with high glucose augments LPS-stimulated production of pro-inflammatory mediators. These findings may explain why periodontal tissue destruction in diabetic patients is more severe than that in non-diabetic individuals.

• 만화애니메이션 연구
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• 통권33호
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• pp.173-202
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• 2013

본 연구 기획개발(development) 단계에 대한 이론적 검토를 통해 한국의 애니메이션 산업 구조에 가장 적합한 제작과정의 초기 단계를 정립시키고자 한다. 그 중요성에 비해 잘 알려지지 않은 기획개발 단계는 애니메이션 제작을 하기 전 어떤 작품을 만들 것인가를 구상하는 단계로서 가장 초기 단계이자 동시에 가장 기초적인 부분이다. 이 단계는 작품의 주제가 결정되고, 제작을 위해 필요한 기초 준비가 이루어지는 단계로서, 애니메이션 제작 과정 중 프리 프로덕션(pre-production) 단계 이전에 설정된다. 기획개발 단계의 역할을 살펴보면 크게 두 가지 유목으로 정리될 수 있다. 하나는 프로젝트 콘텐츠 부분으로서 스토리와 직접적으로 연관되는 것들이다. 구체화된 아이디어를 가지고 제작에 필요한 지원을 받기 위한 활동에 들어갈 준비를 해야 하기 때문에 매우 중요하다. 다른 하나는 프로젝트 제작지원 혹은 사업 부분으로서 재정, 인사, 일정에 관한 부분이다. 이와 같은 업무를 수행해낼 역할과 권한을 가진 자는 바로 제작자(producer) 혹은 총괄제작자(executive producer)이다. 이들의 참여는 기획개발 단계에서도 가능한 빨리 참여하는 것이 중요하다. 구매예정자가 원하는 스타일과 내용을 작가와의 협력을 통해서 만들어내야 하고, 그러한 내용이 과연 애니메이션으로 적합한지를 초기에 판단, 결정해야 하기 때문이다. 기획개발 단계에 대한 연구는 부족하기 때문에 이론화된 모델과 함께 실제사례를 중심으로 한 다양한 관점에서의 연구가 지속되어야 한다.

• 산업경영시스템학회지
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• 제38권3호
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• pp.78-86
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• 2015

Up-to-date business environment for manufacturers is very complex and rapidly changing. In other words, companies are facing a variety of changes, such as diversifying customer requirements, shortening product life cycles, and switching to small quantity batch production. In this situation, the companies are introducing the concept of JIT (just-in-time) to solve the problem of on-time production and on-time delivery for survival. Though many companies have introduced ERP (enterprise resource planning) systems and MRP (material requirement planning) systems, the performance of these systems seems to fall short of expectations. In this paper, the case study on introducing an APS (advanced planning and scheduling) system based on dispatching rules to a machining company and on finding a method to establish an efficient production schedule is presented. The case company has trouble creating an effective production plan and schedule, even though it is equipped with an MRP-based ERP system. The APS system is applied to CNC (computer numerical control) machines, which are key machines of the case company. The overall progress of this research is as follows. First, we collect and analyze the master data on individual products and processes of the case company in order to build a production scheduling model. Second, we perform a pre-allocation simulation based on dispatching rules in order to calculate the priority of each order. Third, we perform a set of production simulations applying the priority value in order to evaluate production lead time and tardiness of pre-defined dispatching rules. Finally, we select the optimal dispatching rule suitable for work situation of the case company. As a result, an improved production schedule leads to an increase in production and reduced production lead time.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2009년도 춘계학술대회 논문집
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• pp.727-730
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• 2009

Highly active and stable nano-sized Ni catalysts supported on MgO-$Al_2O_3$ calcined from hydrotalcite-like materials have been successfully developed with a strong metal to support interaction (SMSI) to enhance the coke resistance in combined $H_2O$ and $CO_2$ reforming of $CH_4$ (CSCRM) for syngas ($H_2$/CO=2) production. The change of the surface area and NiO crystallite size with varying the pre-calcination temperature of support and Mgo content was investigated in relation to the coke resistance. As increasing the pre-calcination temperature, the surface area decreases and the metal to support interaction becomes weak. As a consequence, the coke deposition was more severe on catalysts pre-calcined at high temperature. It was concluded that highly dispersed Ni metal in the surface of Ni/MgO-$Al_2O_3$ catalyst (MgO=30 wt%) pre-calcined at $800^{\circ}C$ had a strong metal to support interaction (SMSI) resulting in an increase of coke resistance and high activity.

• Asian-Australasian Journal of Animal Sciences
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• 제18권5호
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• pp.661-666
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• 2005

The effects of pre-partum feeding management in terms of birth weight, growth, metabolic profile and immunity of calves were studied using 24 crossbred (Bos taurus${\times}$Bos indicus) cows, divided into three equal groups. The dietary treatments included feeding of either 3.0 kg concentrate/head/d throughout the 60 d pre-partum (T$_1$), or 3.0 kg concentrate during 60-22 d pre-partum and thereafter at an increased allowance at 0.25 kg/d during the next 21 d till it reached 1% of live weight (T$_2$). The third group of cows was fed similar to T$_2$, except that the concentrate feeding during 60-22 d pre-partum was reduced to 2.0 kg (T$_3$). All the groups had access to ad libitum green fodder throughout. The results revealed that the mean daily dry matter (DM) intake by the cows was similar (p>0.05) among the three groups during the 60 days of the pre-partum but T2 animals tended to gain more live weight (41.25 kg) than T$_1$ (38.12 kg) and T$_3$ (36.25 kg). The body condition score of the cows did not change appreciably over the experimental period. The mean birth weight of the calves was 24.00${\pm}$1.10, 24.63${\pm}$1.17 and 23.25${\pm}$1.19 kg for the three groups, respectively, with the corresponding average daily gain of 154.2, 155.0 and 169.7 g during the subsequent 60 days; both these parameters did not vary significantly ascribable to prepartum feeding regimens of their dams. The total immunoglobulin (Ig) concentration in the colostrum was 6.31${\pm}$0.34, 5.80${\pm}$0.21 and 6.13${\pm}$0.30 g/dl for the three groups, respectively, showing no influence of dietary treatments. The mean serum Ig levels (T$_1$ 2.10${\pm}$0.09, T$_2$ 2.05${\pm}$0.09 and T$_3$ 2.10${\pm}$0.12 g/dl) of calves at 5 d of age were similar among the dietary groups as was the case with various serum biochemical constituents. It is concluded that the variations in pre-partum dietary management elicited no significant influence on the calf performance including the immune status.

• 대한영양사협회학술지
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• 제19권3호
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• pp.236-252
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• 2013

The purpose of this study was to assess the microbiological quality of home-delivered meals during production and delivery for children from low-income families. Production flows from a facility in Seoul that provides home-delivered meals were analyzed and the time-temperature of the food was measured. Microbiological assessment was performed for the production environment, personal hygiene, and food samples at each production and delivery step based on the process approach. It took 2 hours or longer from completion of production to meal delivery. An aerobic colony count (ACC) and coliform were not detected at knives, cutting boards, and dish towels. However, ACC (at pre-preparation, preparation, and packing areas) and coliform (at the preparation area) were detected on the hands and gloves of employees. Air-borne bacterial counts varied according to day and preparation area (ND~6 CFU/plate/15 min). Food temperatures, on the completion of production and meal delivery, fell into temperature danger zones. ACC and coliform counts of raw ingredients did not decrease after pre-preparation (washing and sanitizing) for menus involving food preparation with no cook step. ACC decreased after cooking step for menus of food preparation with cook step, but the ACC of the stir-fried and seasoned dried filefish fillet on the completion of cooking was too numerous to count due to improper heating. The ACC of seasoned young Chinese cabbages (a menu with complex food preparation) increased during delivery (from 2.5 log CFU/ml to 5.0 log CFU/ml). This qualitative assessment of foodborne pathogens revealed that B. cereus was detected in vegetable and meat product menus. These results suggest time-temperature control is necessary during production and delivery and management guidelines during production of home-delivered meals are provided for safe production.

• 대한한의학회지
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• 제24권2호
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• pp.138-147
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• 2003

Objectives : In this study, we investigated the mechanism by which Chelidonium majus (CM) regulates nitric oxide (NO) production. Methods : Using mouse peritoneal macrophages, the mechanism by which CM regulates NO or tumor necrosis $factor-{\alpha}(TNF-{\alpha})$ production was examined. NO release was measured by the Griess method. $TNF-{\alpha}$ production was measured by the ELISA method. The protein extracts were prepared and samples were analyzed for the inducible NOS(iNOS) expression and nuclear factor kappa $B(NF-{\kappa}B)$ activation by Western blotting. Results : When CM was used in combination with recombinant $interferon-{\gamma}{\;}(rIFN-{\gamma})$, there was a marked cooperative induction of NO production. CM had an effect on NO production by itself. The expression of the iNOS gene was increased in $rIFN-{\gamma}$ plus CM-stimulated peritoneal macrophages and almost completely inhibited by pre-treatment with pyrrolidine dithiocarbamate (PDTC), an inhibitor of $NF-{\kappa}B$. The $NF-{\kappa}B$ activation was increased in rIFN-{\gamma} plus CM-induced peritoneal macrophages. The increased production of NO from $rIFN-{\gamma}$ plus CM-stimulated peritoneal rnacrophages was decreased by the treatment with $N^{G}-monomethyl-{_L}-arginine{\;}(N^{G}MMA){\;}N^{\alpha}-Tosyl-Phe$ chloromethyl ketone (TPCK) , and was almost completely inhibited by pre-treatment with PDTC. Furthermore, treatment with CM alone or rIFN-{\gamma} plus CM in peritoneal macrophages caused a significant increase in $TNF-{\alpha}$ production. PDTC decreased CM-induced $TNF-{\alpha}$ production significantly. After CM treatment in HT-29 or AGS cells, cell viability decreased. Conclusions : These findings demonstrate that CM increases the production of NO and $TNF-{\alpha}{\;}by{\;}rIFN-{\gamma}-primed$ macrophages and suggest that NF-B plays a critical role in mediating these effects of CM.

• 한국물환경학회지
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• 제35권4호
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• pp.299-307
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• 2019

The purpose of this study was to investigate the effect of low temperature thermal pre-treatment on biodegradation of waste activated sludge for anaerobic digestion as a countermeasure for increasing sludge generation. The experimental condition was accomplished in 2 %, 4 %, and 6 % TS concentration, and $70^{\circ}C$, $80^{\circ}C$, $90^{\circ}C$ of temperature for a maximum of 120 minutes retention time. Then, it was followed by analysis of physical/chemical properties, BMP test and composition of biogas. The biogas characteristic was evaluated by applying the modified Gomperz model. As a result, solubility of dissolved substrate, such as $SCOD_{Cr}$, soluble carbohydrate, and soluble protein, and biogas production increased as temperature increased. Solubilization efficiency at $90^{\circ}C$ was 18.4 %, 17.03 % and 16.88% in 2 %, 4 %, and 6 % TS concentration respectively. Also, solubilization rates of carbohydrate and protein similarly increased. BMP test results also showed that methane production in excess sludge increased to 0.194, 0.187 and $0.182m^3/kg$ VS. respectively, and lag phase decreased to 0.145, 0.220, 0.351 day due to acceleration of the hydrolysis step. Consequently, low-temperature thermal pre-treatment could increase biodegradability of sludge, positively affecting biogas production and sludge reduction.