• 한국생활과학회지
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• 제20권6호
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• pp.1153-1165
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• 2011

Decision making for gas boiler consumers depends on the characteristics of products such as the price and quality as well as the brand image. Although a gas boiler is a high involvement product in terms of price, in fact, it is a low involvement product which is greatly affected by installers. This study examined variables which affect the level of satisfaction and repurchase intention by surveying about 1,000 housewives through an on-line questionnaire. The results were as follows: first, gas boiler users' general knowledge of gas boilers showed a correct-answer rate of 54.5%. The average satisfaction score of product quality (mean=5.61 out of 7) was higher than that of the satisfactionscore of the company's service (mean=5.46). Second, the level of repurchase intention was above the mid-point (mean=4.72). Multivariate regression found that product satisfaction, service satisfaction, household size, and information sources explained repurchase intentions for gas boilers to be about 50.7%. Gas boiler marketers should pay attention to the survey result in that the level of repurchase intention depends mainly on both consumer satisfaction and information sources.

• 한국가스학회지
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• 제10권3호
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• pp.60-64
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• 2006

카본블랙 제조공정에서 발생되는 부생가스의 폭발한계와 폭발특성을 연구하였다. 부생 가스의 75% 가량은 수분과 질소였으며 가연성 성분으로는 수소를 비롯한 메탄, 아세틸렌, 일산화탄소 등을 포함하고 있어 연료로 활용하고 있다. 부생 가스중의 가연성 가스 성분들에 의해 공정상에 폭발 및 연소의 위험이 있다. 실험결과 얻어진 폭발한계범위는 17.1%에서 70.7%였으며 르샤틀리에 법칙을 이용하여 예측한 값과는 상당한 차이가 있었다. 또한 폭발특성 실험 결과 폭발압력은 최대 $5.4kg/cm^2$이었고 평균 폭발압력 상승속도는 $39.2kg/cm^2/s$였다. 이러한 결과들은 부생 가스의 취급 및 이용에 따른 폭발이나 화재 사고시 공정과 시설 등에 치명적인 손상을 입힐 수 있으므로 가스폭발 방지 및 방호조치가 필요하다.

• 한국식품영양과학회지
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• 제28권5호
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• pp.997-1002
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• 1999

The aim of the present study was to investigate effects of food preservative addition and changes in composition of herb extract product on the growth of spoilage yeast, Zygosaccharomyces sp. Herbs such as Panax ginseng, Cinnamomum cassia, Lycium chinense, Zyzyphus juiuba and Jingiber officinale were altogether put into water and essence was extracted at 80oC, and then the extract was concentrated at 75oC. The herb extract product was made by adding vitamins, amino acids and honey to the concentrated herb extract. The amount of gas produced from the herb extract product was increased as inoculated cell number increased but decreased as Brix concentration increased. Gases were produced in small amount when incubation was made at 4oC but large amounts of gases were produced at 25 or 40oC of incubation. The gas production and growth of Zygosaccharomyces sp. were measured after browning reaction was induced by heating at 85oC for 12 hours. It appeared that heating treatment did not induce any significant change in the gas production and growth of the cell. The effects of addition of various sugar to the herb extract produce were also invesigated. Amounts of gas production were in the order of glucose>sucrose>oligosaccharide>stevioside. The viable cell count was measured as 6.0$\times$107 CFU/g when glucose was added to the herb extract product. The viable cell counts were 5.0$\times$106, 3.0$\times$103, and 3.0$\times$102 CFU/g in sucrose, oligosaccharide and stevioside added herb extract product, respectively. The amount of gas production from the herb extract product was remarkably reduced by addition of such food preservatives as sodium benzoate and DF 100. TLC(thin layer chromatography) chromatogram of the herb extract showed stability of the herb extract in the above treatments.

• 한국주조공학회지
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• 제23권5호
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• pp.268-275
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• 2003

The mechanism of the hydrogen gas pore formation was investigated in Lost Foam Casting of Al-alloy by reduced pressure test and real casting. The hydrogen gas pick-up was affected by the formed gas during the decomposition of polystyrene in addition to the liquid product. It depended on pouring temperature and a proper temperature of metal front gave the minimum hydrogen pick-up. At a low pouring temperature, the hydrogen went into the melt mainly from entrapped liquid product of polystyrene but pores were formed from the gas as well as the liquid product at a high pouring temperature. The mold flask evacuation down to 710torr decreased the gas porosity down by around 0.4% vol%. The entrapped decomposition product of polystyrene in the melt was observed through the visualization of filling behavior of Al alloy-melt with the high speed camera.

• 한국수소및신에너지학회논문집
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• 제31권4호
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• pp.380-386
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• 2020

This paper represents an analysis of the economic impact of firing natural gas/diesel and natural gas/by-product oil mixtures in diesel engine power plants. The objects of analysis is a power plant with electricity generation capacity (300 kW). Using performance data of original diesel engines, the fuel consumption characteristics of the duel fuel engines were simulated. Then, economic assessment was carried out using the performance data and the net present value method. A special focus was given to the evaluation of fuel cost saving when firing natural gas/diesel and natural gas/by-product oil mixtures instead of the pure diesel firing case. Analyses were performed by assuming fuel price changes in the market as well as by using current prices. The analysis results showed that co-firing of natural gas/diesel and natural gas/by-product oil would provide considerable fuel cost saving, leading to meaningful economic benefits.

• 대한안전경영과학회지
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• 제26권1호
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• pp.99-106
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• 2024

In the event of an emergency such as facility shutdown during process operation, the by-product gas must be urgently discharged to the vent stack to prevent leakage, fire, and explosion. At this time, the explosion drop value of the released by-product gas is calculated using ISO 10156 formula, which is 27.7 vol%. Therefore, it does not correspond to flammable gas because it is less than 13% of the explosion drop value, which is the standard for flammable gas defined by the Occupational Safety and Health Act, and since the explosion drop value is high, it can be seen that the risk of fire explosion is low even if it is discharged urgently with the vent stock. As a result of calculating the range of explosion hazard sites for hydrogen gas discharged to the Bent Stack according to KS C IEC 60079-10-1, 23 meters were calculated. Since hydrogen is lighter than air, electromechanical devices should not be installed within 23 meters of the upper portion of the Bent Stack, and if it is not possible, an explosion-proof electromechanical device suitable for type 1 of dangerous place should be installed. In addition, the height of the stack should be at least 5 meters so that the diffusion of by-product gas is facilitated in case of emergency discharge, and it should be installed so that there are no obstacles around it.

• 전기전자학회논문지
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• 제19권4호
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• pp.541-547
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• 2015

현재 반도체 제조 공정에서 집적회로의 소자 크기가 점점 작아짐에 따라 플라즈마 식각 공정에서의 식각 종료점 검출이 더 어려워지고 있다. 식각 종료점 검출은 위해서는 반도체 장비에 다양한 종류의 센서를 설치하고 이 센서를 통해 데이터를 얻고 분석해야 한다. 기존의 식각 종료점 검출 방식은 주로 By-product의 OES 데이터를 분석하여 진행되었는데 본 연구에서는 By-product 와 Etchant gas 의 OES 데이터를 함께 분석하여 식각 종료점 검출 결과에 신뢰성을 더 높이고자 하였다. 또한, 데이터 분석을 위해 OES-SNR, PCA, Polynomial Regression, eHMM 등의 기법들을 사용하여 진행하였다.

• 한국가스학회지
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• 제17권2호
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• pp.50-58
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• 2013

공정플랜트에는 다양한 배관이 고압, 고온의 인화성, 폭발성 물질을 이송하고 있다. 잦은 설계 변경 및 증설 등으로 복잡한 형상으로 배관이 형성되어 있는 경우가 많으나 배관의 구조가 단순하여 실제 위험성에 비해 안전 관리가 부족한 경우가 많다. 본 연구에서는 국내 한 업체에서 부생가스를 연료로 사용하던 배관을 설계 변경하여 천연가스와 혼합하여 사용하도록 사례를 활용하여, 배관의 안전성을 평가 하는 방법을 예시하였다. 배관의 설계 변경 후 안전성을 ASME 기준에 따라 재평가하고, 배관의 주요 관리부위를 결정하는 방법을 제시하였다. 배관의 분기 및 루프 등이 다수 복잡하게 연결되어있는 가스혼합용 믹싱드럼 배관 시스템을 대상으로 해석하였다. 배관의 주요부위 응력 민감도를 이해하기 위해 배관의 지지대 구속조건 및 외부 온도를 변화시켜 가면서 이들의 영향을 연구하였다. 또한 부생가스가 포함하고 있는 수소가스에 의한 손상 가능성에 대해서도 논의하였다.

• Nuclear Engineering and Technology
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• 제50권1호
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• pp.145-150
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• 2018

A new methodology, the crack-spallation model, has been developed to analyze gas-solid reactions dominated by crack growth inside of the solid reactant and spallation phenomena. The new model physically represents three processes of the reaction progress: (1) diffusion of gas reactant through pores; (2) growth of product particle in pores; and (3) crack and spallation of solid reactant. The validation of this method has been conducted by comparison of results obtained in an experiment for oxidation of $UO_2$ and the shrinking core model. The reaction progress evaluated by the crack-spallation model shows better agreement with the experimental data than that evaluated by the shrinking core model. To understand the trigger point during the reaction progress, a detailed analysis has been conducted. A parametric study also has been performed to determine mass diffusivities of the gas reactant and volume increase constants of the product particles. This method can be appropriately applied to the gas-solid reaction based on the crack and spallation phenomena such as the voloxidation process.

• 신재생에너지
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• 제2권2호
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• pp.118-125
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• 2006

The target of this work was the process development of demonstration plant to produce the high quality alternative fuel oil by the pyrolysis of mixed plastic waste. In the first step of research, the bench-scale units of 70 t/y and the pilot plant of 360 t/y had been developed. Main research contents in this step were the process performance test of pilot plant of 360 ton/year and the development of demonstration plant of 3,000 t/y, which was constructed at Korea R & D Company in Kimjae City. The process performance of pilot plant of 360 t/y showed about 80% yield of liquid product, which was obtained by both light gas oil(LGO) and heavy gas oil(HGO), The boiling point range distribution of LO product that was mainly consisting of olefin components in PONA group appeared at between that of commercial gasoline and kerosene. On the other hand, HO product was mainly paraffin and olefin components and also appeared at upper temperature distribution range than commercial diesel. Gas product showed a high fraction of $C_3\;and\;C_4$ product like LPG composition, but also a high fraction of $CO_2$ and CO by probably a little leak of process.