• Title/Summary/Keyword: Performance Rate

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Numerical and Experimental Study on the Coal Reaction in an Entrained Flow Gasifier (습식분류층 석탄가스화기 수치해석 및 실험적 연구)

  • Kim, Hey-Suk;Choi, Seung-Hee;Hwang, Min-Jung;Song, Woo-Young;Shin, Mi-Soo;Jang, Dong-Soon;Yun, Sang-June;Choi, Young-Chan;Lee, Gae-Goo
    • Journal of Korean Society of Environmental Engineers
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    • v.32 no.2
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    • pp.165-174
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    • 2010
  • The numerical modeling of a coal gasification reaction occurring in an entrained flow coal gasifier is presented in this study. The purposes of this study are to develop a reliable evaluation method of coal gasifier not only for the basic design but also further system operation optimization using a CFD(Computational Fluid Dynamics) method. The coal gasification reaction consists of a series of reaction processes such as water evaporation, coal devolatilization, heterogeneous char reactions, and coal-off gaseous reaction in two-phase, turbulent and radiation participating media. Both numerical and experimental studies are made for the 1.0 ton/day entrained flow coal gasifier installed in the Korea Institute of Energy Research (KIER). The comprehensive computer program in this study is made basically using commercial CFD program by implementing several subroutines necessary for gasification process, which include Eddy-Breakup model together with the harmonic mean approach for turbulent reaction. Further Lagrangian approach in particle trajectory is adopted with the consideration of turbulent effect caused by the non-linearity of drag force, etc. The program developed is successfully evaluated against experimental data such as profiles of temperature and gaseous species concentration together with the cold gas efficiency. Further intensive investigation has been made in terms of the size distribution of pulverized coal particle, the slurry concentration, and the design parameters of gasifier. These parameters considered in this study are compared and evaluated each other through the calculated syngas production rate and cold gas efficiency, appearing to directly affect gasification performance. Considering the complexity of entrained coal gasification, even if the results of this study looks physically reasonable and consistent in parametric study, more efforts of elaborating modeling together with the systematic evaluation against experimental data are necessary for the development of an reliable design tool using CFD method.

Electrochemical Characterization of Anti-Corrosion Film Coated Metal Conditioner Surfaces for Tungsten CMP Applications (텅스텐 화학적-기계적 연마 공정에서 부식방지막이 증착된 금속 컨디셔너 표면의 전기화학적 특성평가)

  • Cho, Byoung-Jun;Kwon, Tae-Young;Kim, Hyuk-Min;Venkatesh, Prasanna;Park, Moon-Seok;Park, Jin-Goo
    • Journal of the Microelectronics and Packaging Society
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    • v.19 no.1
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    • pp.61-66
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    • 2012
  • Chemical Mechanical Planarization (CMP) is a polishing process used in the microelectronic fabrication industries to achieve a globally planar wafer surface for the manufacturing of integrated circuits. Pad conditioning plays an important role in the CMP process to maintain a material removal rate (MRR) and its uniformity. For metal CMP process, highly acidic slurry containing strong oxidizer is being used. It would affect the conditioner surface which normally made of metal such as Nickel and its alloy. If conditioner surface is corroded, diamonds on the conditioner surface would be fallen out from the surface. Because of this phenomenon, not only life time of conditioners is decreased, but also more scratches are generated. To protect the conditioners from corrosion, thin organic film deposition on the metal surface is suggested without requiring current conditioner manufacturing process. To prepare the anti-corrosion film on metal conditioner surface, vapor SAM (self-assembled monolayer) and FC (Fluorocarbon) -CVD (SRN-504, Sorona, Korea) films were prepared on both nickel and nickel alloy surfaces. Vapor SAM method was used for SAM deposition using both Dodecanethiol (DT) and Perfluoroctyltrichloro silane (FOTS). FC films were prepared in different thickness of 10 nm, 50 nm and 100 nm on conditioner surfaces. Electrochemical analysis such as potentiodynamic polarization and impedance, and contact angle measurements were carried out to evaluate the coating characteristics. Impedance data was analyzed by an electrical equivalent circuit model. The observed contact angle is higher than 90o after thin film deposition, which confirms that the coatings deposited on the surfaces are densely packed. The results of potentiodynamic polarization and the impedance show that modified surfaces have better performance than bare metal surfaces which could be applied to increase the life time and reliability of conditioner during W CMP.

Value of Health, Multidimensonal Health Locus of Control and Level of Self-esteem in Low Income Mothers (도시빈곤여성의 건강가치, 건강통제위성격 및 자아존중감과의 관계)

  • Lee, Kwang-Ok;Yang, Soon-Ok
    • Research in Community and Public Health Nursing
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    • v.7 no.1
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    • pp.52-68
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    • 1996
  • As a product of poverty, health means the physical, mental and social instability caused by poverty. High mortality, high morbidity, and unsatisfied needs for medical care indicate the health condition of poor people. These indicators are related to the social and psychological property. This study is to develop an effective method of nursing in the poor family which is an essential unit in the nursing field of the community and to which a fundamental approach is need as a top priority. We can make such a study, though partially, by revealing the relationship among the Health-value, Health Locus of Contol, and the Level of Self esteem. We randomly sampled 243 women who are participating in the nursing department of the comnnity nursing centers in Seoul. We investigated by using questionaries and made an analysis on the result by SAS program. The result of this investigation can summarized as follows : 1. The average age of the subjects investigated is 43.4 and the participation rate in the economic activity is as high as 49.4%. Most of them are paid daily. The average members of the family are 4.28 persons, and 80.2% of which are nuclear families. The type of housing is as follows:51.4% are monthly-rent houses. Rent houses represent 23.5%. And 43.6% of the subjects graduate the high schools 2. The level of self-esteem possessed by the subjects is 37.17. The quality of task performance(3.46) and the morality(3.53) are low as compared with the other qualities. 3. In relation to the locus of control, internality is 22.39, the influence of powerrful others represents 20.24, and the effect of chance occurance is 16.41. 4. The orderings of value scale are the physical and mental health, comfortable life, happiness, mental peace, and pleasure. The lowest order is social recognition. 5. Considering in relation to the self-esteem and the locus of control, we found out that there is a negative relationship among the self-esteem, the influence of powerful others. The lower the level of self-esteem is, the higher the influence of powerful others is. There is also a negative relationship among the detailed items such as the qualities, and the positive attitude. 6. In a significant test in the general characters of the subjects and in the level of self-esteem, we can obtain the follwing results. The higher the economic level is, the higher the level of self-esteem is. And the higher the level of satisfaction with life is, the higher the level of self-esteem is. 7. In the locus of control, the higher the economic level is, the higher the internality is. 8. In the health-level, 75.72% represent the high health -level. And the group which has the low satisfaction with life represents the high level of health-value(81.6%). With these results, we can conclude that the level of self-esteem possessed by the poor women living in the city is high and that they have the multi-dimemsional health-value even though they are living in the poor condtions. Traditionally, the poverty has been recognized as an unfavorale factor in the health care. But this study shows that the poverty is no longer an unfavorale factor and, on the contrary, it has a potential power with which people can improve their health by possessing the high self-esteem and the high health value. The ultimate purpose which the nursing task of the community has is to make the patients keep and improve their own health. So, when the nurses approach the poor patients, the nurses should put an emphasis on the individual responsibilities of the patients, and respect their own health value.

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Synthesis and Electrochemical Properties of Li1-xFeO2-yFy-LixMnO2 (Mn/(Mn + Fe) = 0.8, 0≤y≤0.15)) Cathode Materials by Anion Substitution (음이온 치환을 이용한 Li1-xFeO2-yFy-LixMnO2 (Mn/(Mn + Fe) = 0.8, 0≤y≤0.15) 양극 활물질의 합성 및 전기화학적 특성)

  • Heo, J.B.;Park, G.J.;Lee, Y.S.
    • Journal of the Korean Electrochemical Society
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    • v.10 no.4
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    • pp.239-244
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    • 2007
  • In order to investigate the effect of fluorine ion in the $Li_{1-x}FeO_2Li_xMnO_2$ (Mn/(Mn + Fe) = 0.8) cathode material, it was synthesized $Li_{1-x}FeO_{2-y}F_y-Li_xMnO_2$ (Mn/(Mn + Fe) = 0.8, $0.05{\le}y{\le}0.15$) cathode materials at $350^{\circ}C$ for 10hrs using solid-state method. $Li_{1-x}FeO_{2-y}F_y-Li_xMnO_2$ (Mn/(Mn + Fe) = 0.8, $0.0{\le}y{\le}0.1$ was composed many large needle-like particles of about $1-1.5\;{\mu}m$ and small particles of about 50-100 nm, which were distributed among the larger particles. However, $Li_{1-x}FeO_{1.85}F_{0.15}-Li_xMnO_2$ material showed slightly different particle morphology. The particles of $Li_{1-x}FeO_{1.85}F_{0.15}-Li_xMnO_2$ were suddenly increased and started to be a spherical type of particle shape. $Li/Li_{1-x}FeO_{1.9}F_{0.1}-Li_xMnO_2$ cell showed a high initial discharge capacity of 163 mAh/g and a high cycle retention rate of 95% after 50 cycles. The initial discharge capacity of $Li/Li_{1-x}FeO_{2-y}F_y-Li_xMnO_2$ ($0.05{\le}y{\le}0.15$) cells increased according to the increase of F content. However, the cycleability of this cell was very rapidly decreased when the substituted fluorine content is over 0.1. We suggested that too large amount of F ion fail to substitute into the $Li_{1-x}FeO_2-Li_xMnO_2$ structure, which resulted in the severe decline of battery performance.

Noncondensable gas's influence in waster vapor absorption accompanying interfacial disturbance into aqueous solution of LiBr

  • Dong-Ho RIE;Keun-Oh Lee
    • Journal of the Korean Society of Safety
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    • v.7 no.2
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    • pp.63-70
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    • 1992
  • The aim of this research is to obtain a basic quantitative understanding of the effect of a noncondensable gas on the absorption of water vapor by a $H_2O$ / LiBr combination with n-octanol as the surfactant. Nonflowing aqueous solutions of LiBr (40,45,50 mass%) were exposed to saturated water vapor following the addition of an n-octanol sufactant (0.01 and 0.6 mass%). A small amount of a noncondensable gas (air) was allowed into the absorber (0.03 volume%) and its effect was analyzed by measuring the amount of water vapor absorbed. This study will aid to predict the performance of heat pump and safety operating condition when the noncondensable gas is not allowed in the absorber The results indicate that, in the presence of small amounts of a noncondensable gas, vapor absorption enhancement ratios are less than half o( those obtained under the same experimental conditions when a noncondensable gas is not present (1). The presence of a noncondensable gas causes the partial vapor pressure of air to increase at the vapor / liquid interface, which results in an instability of vapor absorption rate nd. hence, in an inhibition of interfacial disturbance.

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Job Preference Analysis and Job Matching System Development for the Middle Aged Class (중장년층 일자리 요구사항 분석 및 인력 고용 매칭 시스템 개발)

  • Kim, Seongchan;Jang, Jincheul;Kim, Seong Jung;Chin, Hyojin;Yi, Mun Yong
    • Journal of Intelligence and Information Systems
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    • v.22 no.4
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    • pp.247-264
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    • 2016
  • With the rapid acceleration of low-birth rate and population aging, the employment of the neglected groups of people including the middle aged class is a crucial issue in South Korea. In particular, in the 2010s, the number of the middle aged who want to find a new job after retirement age is significantly increasing with the arrival of the retirement time of the baby boom generation (born 1955-1963). Despite the importance of matching jobs to this emerging middle aged class, private job portals as well as the Korean government do not provide any online job service tailored for them. A gigantic amount of job information is available online; however, the current recruiting systems do not meet the demand of the middle aged class as their primary targets are young workers. We are in dire need of a specially designed recruiting system for the middle aged. Meanwhile, when users are searching the desired occupations on the Worknet website, provided by the Korean Ministry of Employment and Labor, users are experiencing discomfort to search for similar jobs because Worknet is providing filtered search results on the basis of exact matches of a preferred job code. Besides, according to our Worknet data analysis, only about 24% of job seekers had landed on a job position consistent with their initial preferred job code while the rest had landed on a position different from their initial preference. To improve the situation, particularly for the middle aged class, we investigate a soft job matching technique by performing the following: 1) we review a user behavior logs of Worknet, which is a public job recruiting system set up by the Korean government and point out key system design implications for the middle aged. Specifically, we analyze the job postings that include preferential tags for the middle aged in order to disclose what types of jobs are in favor of the middle aged; 2) we develope a new occupation classification scheme for the middle aged, Korea Occupation Classification for the Middle-aged (KOCM), based on the similarity between jobs by reorganizing and modifying a general occupation classification scheme. When viewed from the perspective of job placement, an occupation classification scheme is a way to connect the enterprises and job seekers and a basic mechanism for job placement. The key features of KOCM include establishing the Simple Labor category, which is the most requested category by enterprises; and 3) we design MOMA (Middle-aged Occupation Matching Algorithm), which is a hybrid job matching algorithm comprising constraint-based reasoning and case-based reasoning. MOMA incorporates KOCM to expand query to search similar jobs in the database. MOMA utilizes cosine similarity between user requirement and job posting to rank a set of postings in terms of preferred job code, salary, distance, and job type. The developed system using MOMA demonstrates about 20 times of improvement over the hard matching performance. In implementing the algorithm for a web-based application of recruiting system for the middle aged, we also considered the usability issue of making the system easier to use, which is especially important for this particular class of users. That is, we wanted to improve the usability of the system during the job search process for the middle aged users by asking to enter only a few simple and core pieces of information such as preferred job (job code), salary, and (allowable) distance to the working place, enabling the middle aged to find a job suitable to their needs efficiently. The Web site implemented with MOMA should be able to contribute to improving job search of the middle aged class. We also expect the overall approach to be applicable to other groups of people for the improvement of job matching results.

Development of KD- Propeller Series using a New Blade Section (새로운 날개단면을 이용한 KD-프로펠러 씨리즈 개발)

  • J.T. Lee;M.C. Kim;J.W. Ahn;H.C. Kim
    • Journal of the Society of Naval Architects of Korea
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    • v.28 no.2
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    • pp.52-68
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    • 1991
  • A new propeller series is developed using the newly developed blade section(KH18 section) which behaves better cavitation characteristics and higher lift-drag ratio at wide range of angle-of-attack. The pitch and camber distributions are disigned in order to have the same radial and chordwise loading distribution with the selected circumferentially averaged wake input. Since the geometries of the series propeller, such as chord length, thickness, skew and rate distribations, are selected by regression of the recent full scale propeller geometric data, the performance prediction of a propeller at preliminary design stage can be mure realistic. Number of blades of the series propellers is 4 and the expanded blade area ratios are 0.3, 0.45, 0.6 and 0.75. Mean pitch ratios are selected as 0.5, 0.65, 0.8, 0.75 and 1.1 for each expanded area ratio. The new propeller series is composed of 20 propellers and is named as KD(KRISO-DAEWOO) propeller series. Propeller open water tests are performed at the experimental towing tank, and the cavitation observation tests and fluctuating pressure measurements are carried out at the cavitation tunnel of KRISO. $B_{P}-\delta$ curves, which can be used to select the optimum propeller diameter at the preliminary design stage, are derived from a regression analysis of the propeller often water test results. The KD-cavitation chart is derived from the cavitation observation test results by choosing the local maximum lift coefficient and the local cavitation number as parameters. The caviy extent of a propeller can be predicted more accurately by using the KD-cavitation chart at a preliminary design stage, since it is derived from the results of the cavitation observation tests in the selected ship's wake, whereas the existing cavitation charts, such as the Burrill's cavitation chart, are derived from the test results in uniform flow.

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The Effect of Metabolic Syndrome Management Program in a Public Health Center (일개 보건소 대사증후군 관리프로그램의 효과분석)

  • Seo, Jae-Ryoung;Bae, Sang-Soo
    • Journal of agricultural medicine and community health
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    • v.36 no.4
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    • pp.264-279
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    • 2011
  • Objectives: The aims of this study were to evaluate the effect of a metabolic syndrome management program on participants enrolled in a public health center program in, Seoul, Korea for 6 months and to analyze the changes in their life habits and risk factors for treating their metabolic syndrome. Methods: Participants enrolled in a metabolic syndrome program at a public health center and answered questionnaires. Their waist circumference and, blood pressure were measured and their blood was tested. Based on the results, the participants were classified into 3 groups. Then, the center provided a metabolic syndrome management intervention program for the individual groups and analyzed the changes in participants' life habits and risk factors after 6 months. Results: After the intervention, the active group, showed improved physical activity, increased eating habits by 0.7 points, and decreased drinking and smoking; however, these results were not statistically significant. As for the Participants' overall health status, all groups positively changed a statistically significant result. In regard to the change in risk factors for metabolic syndrome in the active group, systolic and diastolic blood pressure and triglyceride levels were, statistically significantly decreased, meanwhile, an increase was found in HDL cholesterol level, waist measurement, and anteprandial glucose level; but the result were not statistically significant. Their review rate was 19.0%; 29.4% in the active group, 19.0% in motivating group A, and 14.5% in motivating group B. Conclusions: Participants showed changes in some life habits and risk factors, a result still far from the program's goal to improve residents' health status (improved living habits and variations in risk factors); thus, it is necessary to supplement this program for better performance.

A Study on the Perception and Attitude of Koreans toward the Welfare Rights (한국인의 "복지권"에 대한 인식과 태도 연구)

  • Kim, Mee-Hye;Jung, Jin-Kyoung
    • Korean Journal of Social Welfare
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    • v.50
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    • pp.33-59
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    • 2002
  • This study aims to provide policy suggestions by examining the perception and attitude of Koreans toward the welfare rights. The study was done through a telephone survey conducted by an opinion research institute on 2,050 respondents in 16 cities and provinces. The results are as follows. First, a majority of Koreans responded that the primary responsibility for welfare rests with the government and perceived their welfare receipt rights in a positive way. Respondents also showed an assertive attitude toward exercising their rights by stating that they intend to file a demurrer or participate in civic activities. Second, in terms of duty performance, most respondents showed different positions concerning tax hike and insurance rate increase, although they showed a stronger opposition to an increase in insurance fee. In addition, 90% of the respondents were in favor of building welfare institutions in the residential area and an overwhelming proportion of the respondents indicated that they would take an active part in welfare development by regularly paying taxes and volunteering. Third, the respondents gave a very negative rating to Koreas welfare system and its overall level. That is, people thought that the level of Koreas welfare system is on a par with that in developing or underdeveloped countries, and that the welfare system benefits no one or only the rich. People generally felt that there was not one proper welfare institution. In conclusion, the study found that Koreans have keen awareness of their welfare rights and proactive attitude toward welfare development, whereas negative viewpoint toward tax and insurance fee increases. This may stem from peoples distrust of government welfare policies and the existing welfare system. This study suggests that welfare policy is an important factor in determining peoples political attitude. Therefore, government authorities must recognize people not as passive receivers of welfare benefit but as active policy partners, and establish policies that reflect peoples high welfare rights perception and willingness to take part in welfare development.

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Smoking Status and Serum NSE Level, as Prognostic Factors in Adenocarcinoma of Lung (원발성 폐선암 환자에서 예후인자로 흡연 및 NSE 수치의 의의)

  • Kim, Hee Kyoo;Ok, Chul Ho;Jung, Mann Hong;Jang, Tae Won
    • Tuberculosis and Respiratory Diseases
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    • v.58 no.6
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    • pp.582-589
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    • 2005
  • Background : The incidence of lung adenocarcinoma, which is more prevalent in women and nonsmokers, is increasing. The aim of this study was to determine the prognostic factors of an adenocarcinoma of the lung. Material and method : The clinical information of patients diagnosed with an adenocarcinoma of the lung at the Kosin University Gospel Hospital from January 1994 to July 2004 was reviewed retrospectively. The survival time of these patients was analyzed by the patient's age, gender, performance status, weight loss, smoking history, location of the primary tumor, clinical stage, serologic tumor markers, and treatment modality. Results : For all 422 patients with an adenocarcinoma of the lung, 247 (58.5%) were male, and their mean age was 59.8 years the. The majority of patients were smokers (58.3%), and the tumors were located in the periphery (59.7%). In the smokers, the tumor was located more in the central airway compared to the non-smokers (42.8% vs. 31.9%, p=0.12). The overall median survival time was 390 days (95% CI;304-436 days). Univariate survival analysis revealed that an older age (${\geq}65$ years old), male, weight loss, smoker, central type, advanced clinical stage, elevated serum carcinoembryonic antigen (CEA, >5 ng/ml) and neuron specific enolase (NSE, >15 ng/ml), and the supportive care only were significantly poor prognostic factors. The median survival time was shorter in the smokers than nonsmokers (289 days vs. 533 days, p<0.001). In addition, it was also shorter in the elevated NSE group than in the normal range group (207 days vs. 469 days, p<0.001). Multivariate analysis showed that age, clinical stage, serum NSE, smoking status, and treatment modality were independent predictors of survival (hazard ratios: 1.68, 1.94, 1.92, 2.39 and 1.57, respectively). Conclusions : Smoking is an important prognostic factor in an adenocarcinoma of the lung, but not gender. This suggests that the better prognosis of women is more related with the lower rate of smoking. In addition, the elevated serum NSE is also an important prognostic in an adenocarcinoma of the lung.