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        검색결과 592

        421.
        2001.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 논문은 경제주간지인 The Economist에서 매분기 발표하는 글로벌 자산관리회사들의 추천 글로벌 주식포트폴리오, 5개 선진국의 주식시장 수익률, 환율변화, 거시경제지표 등의 자료를 토대로 글로벌 포트폴리오 투자관리자의 행태와 성과에 관한 실증분석을 시도하였다. 1989년 1/4분기부터 2000년 2/4분기까지의 연구기간 동안 추천포트폴리오의 시장별 투자성과는 평균적으로 높지 않은 것으로 평가되었다. 이에 따라 이러한 추천포트폴리오를 받아들인 투자자는 심지어 분기 평균으로 손실을 기록할 수도 있었을 것으로 추론된다. 또한 국제투자에서 환위험이 중요한 변수임을 보여주었다. 추천포트폴리오의 분기별 수익률은 Morgan Stanley가 발표하는 벤치마크 세계시장 수익률과 비교하여 성과가 다소 높게 나타났으며, 자산관리회사의 국적별로 성과차이가 존재하였다. 국가별 투자비중은 투자대상 국가들의 거시경제지표와는 상관관계가 낮은 것으로 나타났다. 그러나 환율변화는 유의한 변수로 나타났다. 또한 투자비중 변화들간의 상관관계는 특히 미국시장에 대해 높게 나타났으며, 투자비중 결정에는 해당 국가에 속한 선도 투자회사가 주도적인 역할을 하는 것으로 해석되어, 이에 따라 군집투자 현상도 있는 것으로 추론된다. 또한, 자산관리회사의 주가예측력은 낮은 것으로 평가되었으며, 멕시코, 아시아, 러시아 금융위기시에도 선진국 주식시장에 대한 투자비중은 크게 조정되지 않는 것으로 나타났다.
        9,200원
        422.
        2001.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Quinoline insoluble formed by the heat treatment was hot-pressed near its softening point. The green body was stabilized in the temperature range of 300~400℃ and subsequently carbonized below 1300℃ in an argon atmosphere. The behaviors of QI formation was examined with varying the heat treatment temperature and the lapse of time of the sample carbonized at various temperatures. And the mechanical property, corrosion resistance, and friction behavior were also measured optimum content of mesophase pitch ensured a dense structure and high LC(002) value, which resulted in high mechanical properties, good corrosion resistance, and low-stable friction behavior.
        4,000원
        423.
        2001.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        A petroleum-based isotropic pitch fiber spun by melt-blown method was oxidized in air flow at various conditions. The oxidized pitch fiber obtained was tested for its infusibility and its elemental composition during the process of stabilization. The structural changes were traced by using solvent solubility, FT-IR spectroscopy, and elemental analysis. The samples showed a gradual increase in weight with increasing the oxidization temperature. The weight gain of sample oxidized at 320℃ for 10 min was about 4.5%. The concentration of the pyridine and toluene soluble fraction decreased with an increase in stabilization temperatures. The oxygen uptaken in the stabilization process converted aliphatic side chains into the carbonyl groups. As stabilization proceeded, the more ether and carboxylic acid groups were formed through the oxidations of aldehyde and primary alcohol, and then the carboxylic acid was dehydrated to be aromatic anhydride.
        4,000원
        424.
        2001.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, the effects of carbon black (CB) content and anodic oxidation treatment with AgNO3 on positive temperature coefficient (PTC) behavior of CB/HDPE nanocomposites were investigated. Also, the addition of elastomer as a toughing agent was studied. The 20~50 wt% of CB, 0~5 wtt% of elastomer, and 1 wt% of AgNO3-filled HDPE nanocomposites were prepared using the internal mixer in 60 rpm at 160˚C and the compression-molded at 180˚C for 10 min. As a result, the room temperature resistivity and PTC intensity of the composites were dependent, to a large extent, on the content of CB, addition of elastomer, and surface chemical properties that were controlled in the relative arrangements of the carbon black aggregates in a polymeric matrix. Moreover, the composites with relatively low room temperature resistivity and suitable PTC intensity could be achieved by treatment of AgNO3. Consequently, it was noted that PTC effect was due to the deagglomeration or the breakage of the conductive networks caused by thermal expansion or crystalline melting of the polymeric matrix.
        4,000원
        426.
        2001.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This paper is to estimate the load carrying capacities of concrete-filled steel tubular columns and the important parameters are selected the size, length and concrete strength. he concrete-filled tube structures has many excellent structural properties, that is, high load capacity, good plastic deformation and high resistance local buckling. Under these background, this study Investigated to the structural compression behaviors, the maximum strength, the confinement effects, the fracture mechanism, local buckling failure and concrete strength effects.
        4,000원
        427.
        2001.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this paper, Korean's dining-out behaviors were compared and investigated according to gender and age. The change and the problem of dietary pattern in Korea were understood and we intend to provide the basic information for guidelines of Korean's dietary habits. The subjects are composed of 46.5% male and 53.5% female. According to age, groups aged 10~19 are 26.3%, 20's are 24.6%, 30's are 16.8%, 40's are 18.7%, and 50 and over age group is 13.6%. All of the age groups ate out for celebration of a special day or for social purposes. When dining-out, the most important criteria for selecting a restaurant was the taste of food. All age groups liked Korean-style restaurants the most. All age group eat a house meal at breakfast. At lunch, age groups 40 and below go to a restaurant in school or company and 50 and over age group eats house meal. In general, all age groups ate a house meal at dinner. At breakfast, all the age groups do not eat out. For lunch, they eat out four or five times a week. For dinner, the most of age groups except the 20's eat out two or three times a month and for the 20's age group, two or three times a week. The reason for selecting a Korean-style restaurant is that the food is 'well matched with one's appetite'. According to the above results, the dietary habits of 30 and over age groups are relatively good. On the other hand, in 10's and 20's age groups, they have an irregular meal and the ratio of skipping a meal is high. And they frequently use fast-food restaurants. In the future, the unbalance of nutrition in these age groups is expected. Therefore, the correct nutritional facts should be educated so that these age groups have a healthy dietary habit.
        5,500원
        430.
        2001.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        이 연구는 철근콘크리트 구조물의 비탄성 거동을 파악하고 합리적이면서 경제적인 내진설계기준의 개발을 위한 자료를 제공하는데 그 목적이 있다. 정학하고 올바른 내진성능의 파악을 위하여 비탄선 해석프로그램을 사용하였다. 사용된 프로그램은 철근콘크리트 구조물의 해석을 위해서 유한요소법을 이용하여 개발된 RCAHEST이다. 재료적 비선형성에 대해서는 균열콘크리트에 대한 인장, 압축 전단모델과 콘크리트 소에 있는 철근모델을 조합하여 고려하였다. 이에 대한 콘크리트 균열모델로서는 분산균열모델을 사용하였다. 또한, 횡방향 구속철근으로 인한 강도의 증가 효과를 고려하였다.
        4,300원
        431.
        2001.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study was to investigate the changes in dietary practices, reasons for making dietary changes, current food consumption patterns, and eating habits. Data were collected from 515 parents whose children were attending an elementary school and a middle school in Kimcheon. Among the twenty food groups studied, subjects reported eating more fruit, vegetables, lower-fat meats, high-fat meats, reduced/skim milk, and eggs and less sugar, fats, rice, salt, potato/sweet potato, and chicken. The changes in dietary practices except high-fat meats and salt were significantly different between sex, age, education level, income level, or BMI groups. The primary reason for making dietary changes was 'concerned about family's health'. The average rate of never eating breakfast or less than 2 times per week was found to be 23.2% with a greater rate in younger age group. The rate of breakfast skipping was found to vary between different age and education groups. The regularity of mealtime and overeating practices were significantly different between age groups. Eating out practices were found to vary between different age, education, and income groups. People at younger age group in Kimcheon should be targeted for nutrition education about eating habits. These findings are applicable at the planning and implementation stages of various nutritional improvement projects.
        4,800원
        432.
        2000.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This paper describes the mechanical properties and oxidation resistance of carbon fibers with and without additions of boron oxide additives, and describes the changes in the properties resulting from increased heat treatment temperature (HTT) of the fibers. Carbon fibers in this experiment were heat treated up to 2800℃ each with and without boron oxide treated on the surface of fibers. In the case of boron oxide added carbon fibers, they do not show the improvement of tensile strength and modulus compared to those of no treated carbon fibers below 2200℃ since they are doped substitutionally with boron above 2600℃, which accelerate the graphitization of carbon fibers. Boron oxide implanted carbon fibers showed high resistance to oxidation, however, when carbon fibers were heat treated below 2200℃, they showed almost the same trend of air oxidation.
        4,000원
        433.
        2000.07 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study was to investigate the consumption pattern, behaviors, and motivational attitudes related to fruit and vegetables. Data were collected from 344 mothers whose children were attending an elementary school and a middle school in Kimcheon. The average vegetable expenses were under 10,000 won per week. The frequency of purchasing vegetables was 2-3 times a week. Housewives usually bought the vegetables at local markets and grand shopping centers. As for buying vegetables, housewives considered the organic vegetables, preference, price, and nutrition in order. In the family, the vegetables were favored by husbands most and by sons least. The average fruit expenses were under 10,000 won per week. The frequency of purchasing fruit was 2-3 times a week. Housewives usually bought the fruit at local markets and grand shopping centers. As for buying fruit, housewives considered preference, price, and nutrition in order. The fruit were favored by all members most and by husbands least. Housewives identified barriers to increasing vegetables and fruit consumption, including preference for other foods, lack of availability, cost, and time and effort to prepare. Several implications for nutrition interventions were suggested. First, a key motivation for these women was eating healthy food when they are pregnant, suggesting a persuasive appeal to use in interventions. Second, review of the women's current behaviors led to an identification of four specific behaviors that had the most potential for increasing overall consumption. Finally, the findings suggested ways in which nutrition interventions could address each of the barriers identified.
        4,600원
        435.
        2000.05 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The purposes of this study were to : (a) analyze university students' perception and patronage behaviors to the service quality dimensions, and (b) assist university residence hall foodservices in formulating improved managerial strategies. Questionnaires were hand delivered and mailed to 1,210 university students residing in the residence hall and 13 foodservice managers. A total of 1,011 was usable; resulting in 83.6% response rate. The survey was conducted between October, 1998 and May, 1999. Statistical data analysis was completed using the SAS/Win 6.12 for Descriptive Analysis, 2-test, T-test, ANOVA, and Stepwise Multiple Regression. Forty-seven percent of the respondents indicated that 'taste' was their first priority when choosing a menu. The reasons behind choosing residence hall foodservice were 'location', 'board plan', 'price', 'taste', 'opening hours', and 'menu variety'. The main reasons of dissatisfaction with the residence hall foodservice were 'board plan', 'taste', 'menu variety'. The overall satisfaction score was 2.99 out of 5. The satisfaction score of 「convenience」, 「food quality」 and 「menu variety」were 3.25, 2.94 and 2.76, respectively. Generally, male students were more satisfied than females. Graduate students and students living in residence halls over six semesters were the most dissatisfied with the residence hall foodservice. Residence hall students were dissatisfied with the variables 「menu variety」 and 「facilities」in 'self-operated' operations, whereas 「food quality」, 「menu variety」 and 「price」 in 'contracted' operations. Foodservice operations with 'less than 1,000 meals serving per day' was the highest satisfaction score(3.36) among other serving sizes. Meal price with 'less than 1,300 won' was most satisfied with students. When overall customer satisfaction and service quality dimensions were analyzed by Stepwise Multiple Regression 「food quality」(p〈.001), 「price」(p〈.001), 「facilities」(p〈.001), 「convenience」(p〈.001), 「menu variety」(p〈.001), 「manager's attitude」(p〈.0l), and 「atmosphere」(p〈.01), in decreasing order, significantly impacted on 「overall customer satisfaction」.
        4,900원
        436.
        2000.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This paper is an effort to describe dietary behaviors to keep them healthy among adults. A probability sample was drawn from residents aged between 15 and 60 living in Ulsan City area through a multi-staged cluster sampling method. The data collected by face-to-face interview includes 1,232 respondents. Both univariate and bivariate analyses were employed to describe the dietary behaviors. The dietary behaviors in this study includes preference of taking fat-part of meat, fried food, salty food, hot-taste food, drinking coffee and milk, and taking supplementary medicine. About half of the respondents reported to take fat removed when eating meat, and more than 68% of them preferred not to take any kinds of fried food. With respect to preference of salty and hot-taste food, 39.6% of the respondents take medium-salty and 39.4% do hot-taste food. A third of the respondents drink two-four cups of coffee a day. Those who reported not to drink milk at all were prevalent(37.4% of the respondents) than expected. However, less than 20% of the respondents reported to have any kinds of supplementary health food in a year. These dietary behaviors were examined by sociodemographic characteristics for bivariate analyses.
        4,300원
        438.
        2000.01 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        디지털형 압전/전왜 액츄에이터 응용을 위하여 상경계(반강유전상/강유전상) 조성인 Pb0.94Y0.04[(Zr0.6Sn0.4)0.915Ti0.085]O3 (PYZST) 계를 택하여 과잉 PbO의 첨가량 및 소결 조건 변화에 따른 상전이 특성, 유전 특성 및 전기장 유기변형 특성을 연구하였다. 사방정 구조를 갖는 PYZST 세라믹스에서 과잉 PbO 첨가에 따른 결정구조의 변화는 거의 확인되지 않았으나, 소결 후 입자가 약간 작아지며 둥근 형태로 변화하였고 첨가량 증가에 따라 적정 소결온도는 감소하였다. 과잉 PbO의 첨가량이 증가함에 따라, 분극측정시 반강유전상이 보다 안정되는 경향을 보였고, 전계유도변형 측정시 인가전기장 제거상태에서의 변형의 형상기억성이 감소하고 디지털형 변형곡선 특성이 강화되었다. 또한 최대 유전상수와 전계 유기변형량은 감소하였으나 반면 상전이(반강유전상↔강유전상) 전기장 및 비저항은 증가하는 경향을 나타냈다. 이러한 결과는 과잉으로 첨가된 PbO에 의한 격자 결함반응 및 분역벽 이동 거동 가능성과 연관시켜 설명하였다.
        4,000원
        439.
        1999.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        복합 적층 판과 보강 재를 설치한 보강된 복합 적층 패널의 좌굴을 고려한 설계에서, 좌굴이 항상 구조물의 최종 파손을 의미하는 것은 아니므로 이들의 좌굴 및 좌굴 후 거동에 대한 정확한 이해와 연구가 필요하다. 본 연구에서는 유한요소 법을 이용하여 적층 메커니즘과 섬유 배향각, 적층 순서 등이 복합 적층 판과 보강된 복합 적층 패널의 좌굴 및 좌굴 후 거동에 미치는 영향을 체계적으로 해석하였고, 각 변수에 따른 좌굴 및 좌굴 후 거동 특성을 분석하였다.
        4,000원
        440.
        1999.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 거더 상면에 연장 형성된 수직돌출부의 양측에 상부 플랜지를 가지는 주형과 바닥 면에 모서리보다 형성되어 있는 바닥 판이 현장에서 그라우팅에 의한 전단 키로 연결되어 교량구조물을 형성하는 새로운 형태의 바닥 판 조립식 교량구조를 제안하고 그에 따른 정적실험 및 유한요소해석을 통해 구조거동을 분석하여 실제 적용가능성을 입증하는데 목적이 있다. 먼저 주형과 바닥 판의 연결부에서 발생하는 구조적 평형조건을 입증하기 위해 주형과 바닥 판의 연결부에 스프링 효과를 이용한 유한요소해석을 통해 바닥 판에서 발생하는 부재 력을 해석하였다. 이때 바닥 판에 가장 불리하게 작용하는 하중위치를 관찰하였으며 이를 실제 정적실험 모델과 동일한 유한요소해석결과와 실험결과의 비교로부터 바닥 판 조립식교량은 설계하중 하에서 충분한 저항내력을 확보하고 있는 것으로 나타났다. 또한 정적실험에서의 내외측 주형의 처짐과 유한요소해석결과를 비교한 결과로부터 실험에 의한 처짐이 유한요소해석결과보다 작게 나타났으며 이러한 결과로부터 바닥 판 조립식교량의 실제 강성은 충분한 것으로 증명되었다. 또한 바닥 판 조립식교량에서 주형사이에 가로 보의 설치 갯수에 따른 하중 횡 분배효과 및 바닥 판이 합성된 후의 합성효과 등을 관찰하기 위한 유한 요소해석을 수행하였다. 하중 횡 분배효과는 편심 하중 재하 시에 가로 보의 개수가 3개로 증가하였을 때 가장 현저하게 나타났으며 합성단면에서의 하중 횡 분배는 바닥 판 연결에 의한 합성효과로 인해 비 합성 단면에서의 하중 횡 분배의 약1/2의 크기로써 효과적인 합성효과가 발생하는 것으로 나타났다. Debye 온도를 D=424K로 산출하였다.따른 NiFe층의 자기이방성의 변화는 NiFe/Cu 계면에서 NiFe/Co 계면으로 바뀜에 따른 계면 효과에 의한 것으로 사료되었다./TEX는 0.025ppm이었다. 이 두 살충제는 모기유충에 비하여 미꾸라지와 붕어에 현저히 낮은 독성을 나타내어 미꾸라지에 대한 은 Abate 에서 24.145ppm, Abate-S 에서 10.750ppm이었으며 는 Abate 에서 27.567ppm, Abate-S 에서 14.775ppm이었다. 붕어의 경우에, 은 Abate 에서 7.914ppm 그리고 Abate-S 에서 6.480ppm으로 비교적 안전한 것으로 나타났다. Abate 와 Abate-S 의 붕어에 대한 는 각각 19.898ppm과 8.568ppm으로 모기유충에 비하여 감수성이 매우 낮게 나타났다. 본 실험결과 미꾸라지와 붕어에 안전한 Abate 와 Abate-S 의 최대농도는 모기 유충의 95.0%치사농도의 8배 이상으로 나타나서 다른 수석 무척추동물에 안전하다면 이들 천적어류와 살충제를 동시에 이용한 특정 수역에서 모기의 종합적 방제(Integrated Control)를 수행하는데 매우 유용하게 사용될 수 있을 가능성을 보였다.10), 를 처리한 난자들은 1736.4192.0 (n=10)로써 유의한 (P0.05) 차이를 보였다. 이상의 결과
        4,200원