• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 2000년도 추계학술발표대회 논문집
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• pp.212-215
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• 2000

For the production of high strength constructional glass reinforced plastics and various composite materials continuous glass fibers of high strength and increased modulus of elasticity are used. As is known, the glasses with highest strength were obtained in magnesia alumosilicate and magnesia lime-alumosilicate systems when introducing oxides of titanium and zirconium, boric anhydride, etc. in some cases. The experimental investigations have shown that some glass compositions are characterized by the ratio viscosity/crystallization which is favourable for glass fiber drawing process that permits the attainment of high strength level at the conditions of high temperature glass melting and formation.

• Asian Journal of Business Environment
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• 제12권1호
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• pp.11-16
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• 2022

Purpose: This study is aimed to map the provinces in Indonesia based on the education and ICT indicators using several unsupervised learning algorithms. Research design, data, and methodology: The education and ICT indicators such as student-teacher ratio, illiteracy rate, net enrolment ratio, internet access, computer ownership, are used. Several approaches to get deeper understanding on provincial strength and weakness based on these indicators are implemented. The approaches are Ensemble K-Mean and Fuzzy C Means clustering. Results: There are at least three clusters observed in Indonesia the education quality, participation, facilities and ICT Access. Cluster with high education quality and ICT access are consist of DKI Jakarta, Yogyakarta, Riau Islands, East Kalimantan and Bali. These provinces show rapid economic growth. Meanwhile the other cluster consisting of six provinces (NTT, West Kalimantan, Central Sulawesi, West Sulawesi, North Maluku, and Papua) are the cluster with lower education quality and ICT development which impact their economic growth. Conclusions: The provinces in Indonesia are clustered into three group based on the education attainment and ICT indicators. Some provinces can directly implement e-learning; however, more provinces need to improve the education quality and facilities as well as the ICT infrastructure before implementing the e-learning.

• Advances in concrete construction
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• 제8권1호
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• pp.21-31
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• 2019

The rich recipe of ultra high performance concrete (UHPC) offers the higher mechanical, durability and dense microstructure property. The variable like cement/sand ratio, amount of supplementary cementitious material, water/binder ratio, amount of fiber etc. alters the UHPC hardened properties to any extent. Therefore, to understand the effects of these variables on the performance of UHPC, inevitably a stage-wise development is required. In the present experimental study, the effect of sand/cement ratio, the addition of finer material (fly ash and quartz powder) and, hybrid fiber on the fresh, compressive and microstructural property of UHPC is evaluated. The experiment is conducted in three phases; the first phase evaluates the flow value and strength attainment of ingredients, the second phase evaluates the efficiency of finer materials (fly ash and quartz powder) to develop the UHPC and the third phase evaluate the effect of hybrid fiber on the flow value and strength of ultra high performance hybrid fiber reinforced concrete (UHP-HFRC). It has been seen that the addition of fly ash improves the flow value and compressive strength of UHPC as compared to quartz powder. Further, the usage of hybrid fiber in fly ash contained matrix decreases the flow value and improves the strength of the UHP-HFRC matrix. The dense interface between matrix and fiber and, a higher amount of calcium silicate hydrate (CSH) in fly ash contained UHP-HFRC is revealed by SEM and XRD respectively. The dense interface (bond between the fiber and the UHPC matrix) and the higher CSH formation are the reason for the improvement in the compressive strength of fly ash based UHP-HFRC. The differential thermal analysis (DTA/TGA) shows the similar type of mass loss pattern, however, the amount of mass loss differs in fly ash and quartz powder contained UHP-HFRC.

• 한국심리학회지 : 문화 및 사회문제
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• 제16권3호
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• pp.355-383
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• 2010

본 연구는 기술활용도 측면의 불완전고용이 개인의 자존감과 정신건강에 미치는 영향과, 이러한 영향에 대한 일에 대한 몰입과 사회적 지지의 조절효과를 살펴보고자 수행되었다. 연구는 종단으로 설계되어 2회의 설문조사를 통해 자료가 수집되었다. 1차 조사 시점에서 실업 후 미취업 상태에 있었으나 2차 조사 시점에서는 재취업에 성공한 153명의 자료를 사용하였다. 기술활용도 측면에서의 불완전고용은 두 가지 방식으로 측정되었다. 하나는 '학력격차비'로서 현재의 직업에 요구되는 학력을 기준으로 한 개인의 실제 보유학력의 비율(요구 학력/실제 학력)이고, 다른 하나는 자기보고 방식으로 측정된 '지각된 과잉자격'으로 '성장가능성부재'와 '자격불일치'라는 하위요인으로 구성되었다. 학력격차비는 일에 대한 몰입 및 사회적 지지와 상호작용하여 정신건강에 유의한 영향을 미치는 것으로 나타났다. 일에 대한 몰입 정도가 낮은 경우 학력격차비에 따른 불완전고용의 정도가 높아질수록 사회부적응과 우울·불안의 수준이 높아지는 것으로 나타난 반면, 일에 대한 몰입 정도가 높은 경우 사회부적응과 우울·불안의 정도에 유의미한 변화가 없었다. 사회적 지지도 학력격차비와 상호작용하여, 사회적 지지를 낮게 지각하는 경우 학력격차비에 따른 불완전고용의 정도가 클수록 우울·불안의 수준도 높아지는 것으로 나타났다. 이들 두 조절변인들은 지각된 과잉자격의 두 하위요인과도 상호작용하여 학력격차비와 유사한 패턴의 상호작용효과를 나타냈다. 일에 대한 몰입은 성장가능성부재 및 자격불일치 요인과 상호작용하여 자존감과 우울·불안에 조절효과를 나타냈고, 사회적 지지는 성장가능성부재와만 상호작용하여 우울·불안에 조절효과를 나타냈다. 본 연구 결과는 개인 내적 변인인 일에 대한 몰입과 외부 상황적 변인인 사회적 지지가, 기술활용도 측면의 불완전고용이 자존감과 정신건강에 미치는 영향에 완충효과를 가짐을 시사하고 있다.

• Asian-Australasian Journal of Animal Sciences
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• 제13권10호
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• pp.1429-1432
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• 2000

Three groups of 7, 8 and 8 barrows (22 weeks age; 35 kg body weight), reared on grower diets were fed ad libitum on three isonitrogenous finisher diets containing 50, 71 and 92% wheat bran by replacing maize grain till the attainment of about 74 kg slaughter weight. Growth pattern, average daily gain, feed intake, feed/gain ratio and carcass traits were similar in all the groups. The digestibility of DM, OM, CF, NFE total carbohydrate and energy (DE) decreased (p<0.01) with the increased level of wheat bran in the diet. However, CP digestibility was comparable among all the diet and the digestibility of EE was significantly (p<0.01) higher in grainless diet ($FD_3$). It appears that maize grain may be completely replaced with wheat bran in the diet of crossbred pigs without any adverse effect on their performance with respect to feed intake, body weight gain and carcass characteristics.

• 한국광학회지
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• 제7권4호
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• pp.397-402
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• 1996

레이저 가스를 하나의 횡류팬만으로 순환시키는 동심 원통형 구조의 소형 엑시머레이저를 개발하였다. 이 방치를 1kHz의 고속으로 반복동작시켰을 때 KrF 레이저의 평균출력은 56watt였다. 본 논문에서는 kHz급의 소형 엑시머레이저를 실현할 수 있는 설계 파라메터와 레이저 가스의 CR(Clearing Ratio)특성을 분석하였다. 평균출력 56watt일 때 레이저 효율은 1.2%, CR은 2.97, 출력변동율 .+-.9%이다. 이때 레이저 가스용적은 10 liter이고 방전체적은 1.8(높이)*1.2(폭)*30(길이)=64.8$cm^{3}$이다.

• 한국국방경영분석학회지
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• 제3권1호
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• pp.83-96
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• 1977

The combustion chamber and nozzle of an end burning, small spherical rocket is designed. A spherical external shape has a number of advantages such as fixed center-of-gravity and minimum aerodynamic precession torques during flight and a better mass distribution for gyro-stabilization as contrasted to a conventional ogive rocket shape. It is shown that the cross-sectional variation of the end burning solid propellant with length is an exponential geometry to provide a constant thrust-weight ratio of the rocket device during the propellant burning period, and that the factors which affect the attainment of the constant relationship of thrust to weight in the design are the initial propellant area, initial weight of the rocket and propellant density. The measurement of the transient thrust in the ground static test using black powder propellant supports the predicted results. A wind tunnel having a $30{\times}30{\times}75cm$ test section and Mach number 0.11 is constructed, and a simple balance-type device is designed for the measurement of the drag of a spinning sphere. The experimental results indicate that the. spinning has no effect on the magnitude of the drag up to the Reynolds number $3{\times}10^5$. Numerical computation of the flight trajectories for various launching angles is presented, and the gyro-stabilization of spinning sphere is discussed.

• 한국산학기술학회논문지
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• 제13권1호
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• pp.45-50
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• 2012

본 논문은 CNC 선반에서 Al-6061의 보링 선삭 후 진원도 오차 분석에 관한 것이다. 실험은 실험계획법을 기초로 하여 신호대 잡음비, 분산분석을 사용하여 진원도 오차에 관한 파라미터의 영향을 연구하였다. 그리고 다중선형회귀분석은 진원도 오차의 예측 가능한 수학적 모델을 유도하기 위해 적용되었다. 선삭 파라미터인 고정압, 벽두께, 절삭깊이 그리고 이송속도는 논문의 목적달성을 위해 적용되었고 그 결과를 고찰하였다.

• Journal of Preventive Medicine and Public Health
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• 제52권6호
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• pp.405-415
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• 2019

Objectives: The aim of this study was to evaluate the associations of frailty with perceived neighborhood walkability and environmental pollution among community-dwelling older adults in rural areas. Methods: The participants were 808 community-dwelling men and women aged 65 years and older in 2 rural towns. Comprehensive information, including demographics, socioeconomic status, grip strength, polypharmacy, perceived neighborhood environment (specifically, walkability and environmental pollution), and frailty, was collected from participants using face-to-face interviews conducted between June and August 2018. Perceived neighborhood walkability was measured using 20 items that were selected and revised from the Neighborhood Environment Walkability Scale, the Neighborhood Walkability Checklist from the National Heart Foundation of Australia, and the Physical Activity Neighborhood Environment Survey. The Kaigo-Yobo Checklist was used to assess participants' frailty. Results: The overall prevalence of frailty in this community-dwelling population was 35.5%. Sex, age, cohabitation status, educational attainment, employment status, grip strength, and polypharmacy were significantly associated with frailty. In the logistic regression analysis, frailty was associated with low perceived neighborhood walkability (adjusted odds ratio [aOR], 0.881; 95% confidence interval [CI], 0.833 to 0.932; p<0.001) and severe perceived neighborhood environmental pollution (aOR, 1.052; 95% CI, 1.017 to 1.087; p=0.003) after adjusting for sex, age, cohabitation status, educational attainment, employment status, monthly income, grip strength, and polypharmacy. Conclusions: More studies are warranted to establish causal relationships between walkability and environmental pollution and frailty.

• 한국생활과학회지
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• 제21권3호
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• pp.611-628
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• 2012

The purpose of this study was to examine influence of home energy cost on housing cost burden of Korean and U.S. monthly renter households in urban areas and to explore influences of household and housing characteristics on their home energy cost burden. Microdata for this research was extracted from the 2011 Korean Household Budget Survey and 2009 American Housing Survey. Monthly renter households in urban areas were initially grouped based on household income, followed by a detailed analysis of housing and home energy cost. Findings are as follows: (1) The maximum ratio of home energy cost to household house hold income in Korea was 49% compared to 83% in the US; (2) Energy cost to income ratio were found to have significant influences on housing cost burden and lower income households' housing cost burden was found more vulnerable to their energy cost; (3) In general, the energy cost burden of low-income renter households in Korea tended to be influenced by household size, the number of household members staying at home during daytime hours and housing unit size. The energy cost burden of low-income renter households in the U.S. tended to be influenced by home structure type, size and age, the householder's age, race, educational attainment, the household size, number of wage earners per household, income, and the number of household members between 7 and 17 years of age.