• 한국수소및신에너지학회논문집
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• 제24권6호
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• pp.573-579
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• 2013

Hydrogen engine with homogeneous charged compression ignition can achieve high efficiency by high compression ratio and rapid chemical reaction rates spatially. However, it needs to expansion of the operation range with over-all load conditions which is very narrow due to extremely high pressure rise rate. The adoption of the lean boosting in a HCCI $H_2$ engine is expected to be effective in expansion of operation range since minimum compression ratio for spontaneous ignition is decreased by low temperature combustion and increased surround in-cylinder pressure. In order to grasp its possibility by using lean boosting in the HCCI $H_2$ engine, compression ratio required for spontaneous ignition, expansion degree of the operation range and over-all engine performance are experimentally analyzed with the boosting pressure and supply energy. As the results, it is found that minimum compression ratio for spontaneous ignition is down to the compression ratio(${\varepsilon}$=19) of conventional diesel engine due to decreased self-ignition temperature, and operation range is extended to 170% in term of the equivalence ratio and 12 times in term of the supply energy than that of naturally aspirated type. Though indicated thermal efficiency is decreased by reduced compression ratio, it is over at least 46%.

• 한국지열·수열에너지학회논문집
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• 제20권1호
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• pp.1-7
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• 2024

To In this study, a nozzle which is designed to work as expansion device was installed in a refrigeration system and performance test was conducted. The nozzle has 0.8mm, 1.0mm, 1.2mm diameter and inserted in a body of the devices. System performance was compared with a electronic expansion device(EEV, electric expansion valve) and designed nozzles at the environmental conditions such as dry bulb and wet bulb temperature. To reduce energy loss in the evaporator, a nozzle was inserted into the evaporator. In the comparison test, the opening of the EEV was adjusted to the same diameter as the 3 nozzles, and the experiments conducted at a 27℃ dry bulb temperature and 19.5℃ wet bulb temperature with 50% relative humidity as defined at KS C 9306 standard. To find out the effect of the environmental condition, the bulb temperature was varied 5 degree lower and higher than the standard condition temperature with the same relative humidity condition at 50%. The air flow rate to the evaporator was also changed 4, 7 and 10 m³/min. As results, the temperature drop in the nozzle was 153% higher than that of the EEV and the enhancement of the performance(COP) was up to 125.7% if install the nozzles in the refrigeration system. The highest performance was obatained at 1.0mm diameter nozzle.

• 한국문헌정보학회지
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• 제40권3호
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• pp.289-304
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• 2006

본 연구에서는 단어의 의미연상을 이용하여 시소러스를 구축하고. 이 시소러스에 대해 탐색 시소러스로서의 기능성을 확인하기 위해 질의확장 실험을 수행하였다 연상 시소러스 구축을 위해 문헌정보학 분야를 대상으로 단어연상검사를 실시한 후 자극어와 반응어간의 의미관계를 파악하고 반응어와 기존 시소러스의 디스크립터를 비교 분석하였다. 실험 및 분석결과. 단어연상검사를 이용하여 시소러스를 구축하면 기존의 시소러스에 비해 연관관계 용어들을 시소러스에 다양하게 반영할 수 있으며, 통제어휘집에 나타난 하위관계와 동등관계 용어들을 어느 정도 반영할 수 있다는 것을 확인하였다. 또한 질의확장 실험결과 단어연상 시소러스가 기존 시소러스에 비해 비교적 우수한 성능을 보여 단어연상 시소러스가 정보검색환경에서 질의 확장에 응용될 수 있음을 증명하였다.

• 한국화재소방학회논문지
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• 제21권1호
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• pp.19-28
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• 2007

구급대원의 직무만족도를 조사한 결과 119구급대원의 업무스트레스 정도는 업무스트레스 척도를 구성하고 있는 영역 전체 평균 4점 만점의 2.54(SD.44)점이었다. 119구급대원이 느끼는 영역별 피로 정도는 영역 전체 평균 4점 만점의 2.09(SD.49)점로 나타났다. 119구급대원의 직무만족도 정도는 전체 평균 5점 만점의 2.71점으로 조사됐다. 본 연구는 구급대원의 직무만족도 향상을 위해 구급대원의 신규채용확대, 임용전 교육실시, 해외연수 등을 통한 구급대원의 지속적인 교육훈련, 구급장비의 지원확대와 현대화, OAT제도 도입운영 등의 방안을 제시하였다.

• 한국식품조리과학회지
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• 제10권4호
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• pp.405-411
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• 1994

This study was conducted to know the quality of chou made with flour pastes which were stored at different conditions of quick freezing, slow freezing, cold and room temperature. Also, this study included investigation of the chou properties such as expansion, sensory evaluation, degree of gelatinization, and physical and structural properties of paste were observed. There were not significant differences m diameter, height, volume, appearance, hollow formation, and sensory evaluation between the chou made with the paste stored at freezing condition and chou directly baked after pasting. Quick and slow freezing storages did not significantly affect the properties of chou, and the same results were obtained among the chou made with pastes thawed at room temperature and in microwave ovenrange. The chou of pastes stored at room temperature and in microwave ovenrange. The chou of pastes stored at room temperature and stored in refrigerator showed lowed expansion and value of sensory evaluation than those of frozen pastes. The paste stored at room temperature had the lowest hardness and viscosity compared with the other storage conditions. According to the observation of light microscope. the lipid bodies of the paste of freezing storage smaller those of the room temperature and refrigerator storage. The expantion of chou made with paste stored at room temperature was greatly decreased due to the high coalescence of lipid bodies, and also the paste components such as lipid, starch granule gluten at room temperature had inferior dispersion condition. The general tendency of the degree of gelatinization of chou were low in all treatments of paste. The values were 23.5%~46.0% in freezing, 77.3% in room temperature, 68.7% in directly baked after pasting, and 61.0% in cold storage, respectively. The formation and the taste of chou made with frozen paste were similar to those of chou directly baked pasting.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제50권4호
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• pp.197-205
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• 2024

Objectives: To evaluate the effectiveness of decompression and various parameters that may affect volume change in cystic lesions. Patients and Methods: This retrospective study included patients who visited the Department of Oral and Maxillofacial Surgery at Ewha Womans University Medical Center between 2012 and 2022 for decompression of cystic lesions of the jaw. To measure volume changes, pre- and post-decompression cone-beam computed tomography was performed and reconstructed in three dimensions using Mimics 25.0 software (Materialise NV). A comparative analysis was performed based on sex, age, initial cyst volume, location, degree of cortical layer expansion, and pathologic diagnosis using the Mann-Whitney U and Kruskal-Wallis tests. Results: In all 20 cases, the duration of decompression was 7.84±3.35 months, and all patients successfully completed the decompression period without any complications. Significant differences were observed in the reduction rate and shrinkage speed based on the degree of cortical layer expansion. However, only the shrinkage speed (not the reduction rate) showed a significant difference with respect to the initial cyst volume. Significant differences were not observed based on sex, age, location, or pathologic diagnosis. Conclusion: Although the present study involved a small number of cases, the effectiveness of decompression was confirmed. In particular, 3D analysis overcame the shortcomings of previous studies of decompression and allowed earlier resection. Further studies with more patients are required to provide a rationale for these results and identify factors that influence decompression.

• 한국가축번식학회지
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• 제10권2호
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• pp.211-217
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• 1986

This experiment was conducted to determine the effect of FSH on in vitro maturation and in vitro fertilizing ability of oocytes recovered from normal follicles of different sizes in superovulated rabbits. Follicular oocytes recovered were cultured in modified Ham's F12 medium containing 0, 0.1, 1.0 and 10$\mu\textrm{g}$ FSH/ml for 18 hours and investigated the degree of cumulus cells expansion and nuclear maturation, which were fertilized with in vivo capacitated rabbit sperm. 1. The number of normal follicles<1.5mm, 1.6 to 2.5mm and> 2.5mm in diameter at 16 to 18hrs after HCG administration was 4.8 (38.8%), 5.5(45.4%) and 3.3(15.8%), respectively. Average percent of oocytes recovered was 69.7% and larger follicles tended to have a higher percent, recovery rate than smaller follicles. 2. The degree of cumulus expansion in medium containing 0.1$\mu\textrm{g}$ FSH/ml was similar to that of control, but markedly decreased under the level of above 1$\mu\textrm{g}$ FSH/ml. The proportions of oocytes which reached the second meiotic metaphase were 57.1, 61.5, 43.8 and 45.0% in medium containing 0, 0.1, 1.0 and 10$\mu\textrm{g}$ FSH/ml, respectively. Oocytes from larger follicles showed a higher nuclear maturation than that from smaller follicles. 3. In vitro fertilization rate of oocytes matured under 1$\mu\textrm{g}$ FSH/ml was slightly, not significant, higher than that of others. 4. Progesterone level in follicular fluid was about 67 to 71ng/ml with no difference in follicular sizes and estradiol-17$\beta$ level was under 25pg/ml.

• 한국식품과학회지
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• 제47권2호
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• pp.211-216
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• 2015

카레분말의 주원료인 강황을 유과 제조에 이용함으로써 유과의 기능성을 향상시켜 노인용 간식으로 발전시키려는 목적으로 찹쌀가루의 각각 5, 10, 15, 20%를 카레분말로 대체하여 유과를 제조한 결과, 카레분말의 첨가량이 많아질수록 경도는 증가하였으나, 바삭함에는 유의적 차이가 없었다. 색은 카레분말 첨가량에 비례하여 노란색이 유의적으로 증가하였고, 과산화물가와 산가를 측정한 결과 카레분말을 15% 이상 첨가할 경우, 효과적으로 유과의 산패를 억제할 수 있었다. 관능검사결과, 카레분말을 첨가한 유과는 첨가하지 않은 대조군에 비해 관능적 특성이 향상되었으나, 20% 첨가한 경우 짠 맛이 두드러지게 나타났다. 여러 특성들을 종합해 본 결과, 유과에 첨가하는 카레분말의 양은 찹쌀가루의 15%가 가장 적당한 것으로 보여진다.

• 한국식품영양과학회지
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• 제30권6호
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• pp.1088-1094
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• 2001

유과의 팽화도는 홍화종실 분말 첨가량이 증가할수록 감소하였으나, 기름흡수율은 반면에 홍화종실 분말 첨가량이 많을수록 높아졌다. 유과의 수분함량은 홍화종실 분말 5% 첨가군이 가장 높게 나타나 흥화종실 분말의 섬유소가 유과의 이화학적 특성에 영향을 미치는 것으로 나타났다. 관능검사의 기호도 측정에서 외관의 기호도와 맛의 기호도는 홍화종실 분말 1% 첨가군이 가장 좋다고 평가하였으며, 첨가량이 증가할수록 낮게 평가되었다. 전반적인 기호도는 홍화분말 1% 첨가군을 가장 선호하는 경향을 보였으며, 대조군이 그 다음 순으로 나타났다. 색도측정 결과 명도 L값은 홍화종실 분말 첨가량이 증가할수록 감소한 반면 적 색도 a값과 황색도 b값은 증가하였다. 조직감 측정에서 경도는 첨가량이 증가할수록 낮아졌으며, 응집성은 1% 첨가군이 가장 높았다. 관능검사와 기계적 검사의 상관관계에서 경도와 부서짐성이 높을수록 기호도가 높게 나타났다. 이화학적 검사와 기계적 검사의 상관관계에서는 팽화도가 높을수록 응집성과 탄력성이 높았고. 지방흡수율과 수분함량이 높을수록 껌성이 높게 나타났다. 이상의 결과 흥화분말 1% 첨가군의 품질특성이 가장 높게 평가되어 유과 제조시 홍화종실 분말의 첨가량은 1%정도가 적당하다고 사료된다.

• 복식
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• 제65권6호
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• pp.25-35
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• 2015

The purpose of this study is to investigate the characteristics of members and communities that have significant influence in the online fashion community through their word-of-mouth activities. In order to identify the influence and the diffusion of word-of-mouth in fashion community, the study selected one online fashion community. Then, the study sorted the online posts and comments made on fashion information and put them into the matrix form to perform social network analysis. The result of the analysis is as follows: First, the fashion community network used in the study has many active members that relay information very quickly. Average time for information diffusion is very short, taking only one or two days in most cases. Second, the influence of word-of-mouth is led by key information produced from only a few members. The number of influential members account for less than 20% of the total number of community members, which indicate high level of degree centrality. The diffusion of word-of-mouth is led by even fewer members, which represent high level of betweenness centrality, compared to the case of degree centrality. Third, component characteristic shares similar information with about 70% of all members being linked to maximize information influence and diffusion. Fourth, a node with high degree centrality and betweenness centrality shares similar interests, presenting strain effect to particular information. Specially, members with high betweenness centrality show similar interests with members of high degree centrality. The members with high betweenness centrality also help expansion of related information by actively commenting on posts. The result of this research emphasizes the necessity of creation and management of network to efficiently convey fashion information by identifying key members with high level of information influence and diffusion to enhance the outcome of online word-of-mouth.