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        검색결과 1,832

        1201.
        1995.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        등유전성 용매로 알려진 methanol과 acetonitrile의 이성분 혼합용매에서 p-치환 benzyl bromide와 p-치환 N, N-dimethylaniline과의 친핵성 치환반응을 반응속도론적으로 연구하여 다음과 같은 결론을 얻었다. 1. Hammett ρ_X값으로부터 전이상태에서 반응기질의 반응 중심 원자에 양(+)하전이 증가하고 결합 형성보다는 결합파괴가 진전됨을 알 수 있었다. 그러나 친핵체에 -NO_2기가 치환된 Y-p-NO_2인 경우 반응 중심 원자에 음(-)하선이 증가하여 결합파괴와 동시에 결합형성도 크게 진전되었음을 알 수 있었다. 2. Hammett ρ_Y값으로부터 기질의 치환기가 전자주게기일수록 결합형성이 작게 되고 기질의 치환기가 전자 받게기일수록 결합형성이 크대 되었음을 알 수 있었다. 3. 교차 상호작용 상수, ρ_XY값으로부터 80%(v/v)의 methanol조성에서 친핵체가 반응 기질을 공격하는 능력이 가장 크게 나타나고 동시에 결합형성이 잘 진전됨을 보여 주었다. 4. 퍼텐셜 에너지 표면 모델에 적용했을 때 반응은 각 반응지수로부터 구한 반응물의 전이상태의 구조와 잘 일치하였다. 5. 분광용매화 피라미터식에 적용하였더니 본 반응은 용매의 편극-극성 효과에 크게 지배됨을 알 수 있었다.
        4,300원
        1202.
        1995.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        자동단열온실시스템을 개발할 목적으로 실험용 온실의 천정과 벽체를 이중벽으로 제작하여 이중벽 내부에 단열입자를 자동으로 충전 회수할 수 있도록 시스템을 구성하여, 입자의 송풍성능, 투광성, 입자의 마모실험, 온실의 단열성능 및 차광효과를 분석한 결과를 요약하면 다음과 같다. 1. 약 2㎥의 입자를 충전 회수하는데 약 1시간 15분이 소요되었으나, 온실의 규모에 적합한 송풍기의 용량, 배기구의 면적, 충전관 및 회수관의 조절로 소요시간을 감소시킬 수 있을 것으로 판단되었다. 2. 단열입자의 회수 직후에 이중벽온실의 투광성을 객관성 있게 평가할 수 있는 10시에서 15시까지의 평균 투광율은 67%로 나타났다. 3. 입자의 충전 및 회수를 직송방식으로 하였을 때, 입자마모율이 연속 5개월 사용시 20%로 나타나, 입자의 충전 및 회수를 간접방식으로 수행하는 것이 타당한 것으로 분석되었다. 4. 겨울철 야간에 단열입자를 회수한 이중벽 온실의 내부온도는 외기온보다 평균 3.4℃ 높았으나, 입자를 충전한 단열온실의 내부온도는 단열면적비가 73%일때 외기온보다 평균 6.6℃ 높았고, 단열면적비가 100%일때 외기온보다 평균 13.5℃ 높게 나타나 단열온실의 야간단열성능이 우수함을 알 수 있었다. 5. 일사가 양호하고 외기온이 높은 주간에 입자를 충전한 단열온실(단열면적비 100%)의 차광성능을 분석한 결과, 외기온의 평균이 36.9℃일 때 온실내부온도의 평균은 30℃로 외기온보다 평균 7℃ 낮게 나타나 차광효과가 크다는 사실을 알 수 있었다.
        4,000원
        1205.
        1995.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        One of the most destructive forces around greenhouses is wind. Wind loads can be obtained by multiplying velocity pressure by dimensionless wind force coefficient. Generally, wind force coefficients can be determined by wind tunnel experiments. The wind force coefficient distribution on a single - span arched greenhouse was estimated using experimental data and compared with reported values from various countries. The results obtained are as follows : 1. The coefficients obtained from this study agree with the values proposed by G. L. Nelson except about 0.5 of difference in the middle region of roof section. This discrepancy is mainly attributed to the dissimilarity of experimental conditions (or wind tunnel test such as Reynolds number, type of terrain, surface roughness of model, location of the lapping and measuring methods. 2. Considering that the wind force coefficients are varied along the height of a wall at wind direction perpendicular to wall, structural analysis using subdivided wind force coefficient distribution is more resonable for wall. 3. It is recommendable that wind force coefficient distribution on a roof should take more subdivision than the existing four equal divisions for more accurate structural design. 4. Structural design using wind forces close to real values is more advantageous in safety and expense.
        4,000원
        1207.
        1994.12 구독 인증기관 무료, 개인회원 유료
        The Purpose of this study was to establish the belter residential environment in Apt. complex. In this study, the management consciousness of exterior space and the degree of satisfaction were investigated and analyzed on the GI-SAN Apt. complex in Taegu city. The data were obtained through the questionnaire survey about the exterior space of Apt. complex and analyzed by the SPSS/PC. The results of this analysis are as follow; The result of the image analysis were the cleanness factor and the arrangement factor, which have great influenced in residents image of exterior space. The dissatisfaction source of the management conditions were owing to the lake of management techniques and the discord of residents. The subject of management in the residents consciousness was the management office. In additionally, the management form by the residents were highly showed the cleaning and weeding. The main issues of their dissatisfaction about the exterior space was the lake of size, quantity of plants and rest space. The place of the most demand on management was investigated the children playground which was regarded to be the most damaged.
        4,800원
        1208.
        1994.04 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        일방향 응고한 AI-CuAI2공정 복합재료의 미세조직에 미치는 응고조건과 진동의 영향에 대해서 조사하였다. 진동하에서 성장속도(R) 변화에 따라 일방향응고 시켰을때 열구배(G)는 32˚C/cm와 35˚C/cm를 유지했다. 공정조직은 성장조건(G/R)에 따라 변화되었다. 조직미세화는 진동의 영향도 컸지만 G/R의 영향이 더 크다는 것을 알 수 있었다. 층상 간격은 λ2 =상수 라는 관계에 따라 성장속도와 더불어 변화 되었다.
        4,000원
        1209.
        1994.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        D-xylan은 최근 대체 에너지원인 알콜 생산의 기질로서 주목받고 있을 뿐만 아니라 butanol과 butandiol과 같은 유기 용매와 xylitol과 같은 감미료, xylooligosaccharide와 같은 bifidogenic factor 등의 원료로 사용된다. 본 논문에서는 발효된 톱밥으로부터 xylanase 강력 생산성 균주를 분리하고 제 특성을 확인하여 Bacillus sp. GS로 동정하였다. Xylanase 생산성을 높이기 위해 효소 생산 배지 성분과 배양 조건을 최적화 하였는데, 각각 xylan 1.25%, yeast extract 0.1%, NaNO_3 1.2%, K_2HPO_4 0.1%, MgSO_4 0.02%, mineral salt 0.005%와 pH 6.5, 배양 온도 37℃였다.
        4,000원
        1210.
        1993.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The Automated Eichner Iris Photometer(AEIP) at the Korea Basic Science Center was tested for its function and the proper procedure for photographic photometry. The AEIP requires about three hours for reaching the electrical stability. When the iris is controlled automatically, the repeatability of density unit (DU) is accurate in the uncertainty of (0.0028∼0.0048 0.0028∼0.0048 )DU. The iris reading is found to be accurate within the mean error of 0.m05 0.m05 , which could be reduced to 0.m02 0.m02 by the manual control. To check the applicability of the AEIP. each two photographic plates for UBV colors which were taken by Dupuy and Zukauskas(l976) for the open cluster Byur 2, were measured by using the AEIP. and the photographic magnitudes and colors of the stars in Byur 2 were determined. discussing the previous results.
        5,500원
        1217.
        1993.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The wind pressure distributions were analyzed through the wind tunnel experiment to provide fundamental criteria for the structural design on the three-span arched house according to the wind directions. In order to investigate the wind force distribution, the variation of the wind force coefficients, the mean wind force coefficients, the drag force coefficients and the lift force coefficients were estimated from the experimental data. The results obtained are as follows : 1. The variation of the wind force with the wind directions on the side walls was the greatest at the upwind edge of the walls. The change of pressure from the positive to the negative on the side walls occurred at the wind direction of 30˚ in the first house and 60˚ in the third house. 2. The maximum negative wind force along the length of the roof appeared at the length ratio of 0-0.2, when the wind directions were 90˚ in the first house, 60˚ in the second house and 30˚ in the third house. 3. The maximum negative wind force along the width of the roof appeared at the width ratio and the wind direction of 0.4 and 0˚ in the first house, 0.4-0.6 and 30˚ in the second house and 0.6 and 30˚ in the third house, respectively. 4. The maximum mean positive and negative wind forces occurred at the wind direction of 60˚ and 30˚, respectively, on the side walls of the first house, and the maximum mean negative wind force on the roof occurred at the wind direction of 30˚ in third house. 5. The maximum drag and lift forces occurred at the wind direction of 30˚, and the maximum lift force appeared in the third house. 6. The parts to be considered for the local wind forces were the edges of the walls, the edges of the x-direction of the roofs, and the locations of the width ratio of 0.4 of the first and third house and the center of the width of the second house for the y-direction of the roofs.
        4,000원
        1218.
        1992.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The wind pressure distributions were analyzed to provide fundamental criteria for the structural design on the two-span arched house according to the wind directions through the wind tunnel experiment. In order to investigate the wind force distributions, the variation of the wind force coefficients, the mean wind force coefficients, the drag force coefficients and the lift force coefficients were estimated using the experimental data. The results obtained are as follows : 1. The variation of the wind force with wind directions on the side walls was the greatest at the upwind edge of the walls. 2. The maximum negative wind force along the length of the roof appeared at the upwind edge at the wind direction of 60˚. 3. The maximum negative wind force along the width of the roof appeared at the width ratio and wind direction of 0˚ and 0.4 in the first house and 0.6 and 30˚ in the second house, respectively. 4. The mean negative wind force on the side walls of the first house at the wind direction of 0˚ was far greater than that of the second house, and the maximum negative wind force on the roof occurred at the wind direction of 30˚. 5. The maximum lift force appeared on the second house at the wind direction of 30˚, but the lift force on the first house was far greater than that on the second house at the wind direction of 0˚. 6. The parts to be considered for the local wind forces were the edges of the walls, and the edges of the x-direction and the width ratio, 0.4 of the y-direction in the roofs.
        4,000원
        1219.
        1992.12 구독 인증기관 무료, 개인회원 유료
        기관분화(器官分化)된 유채의 조직으로부터 재분화되는 식물체의 획득빈도를 높이고자 이에 관여하는 몇가지 요인에 대한 실험을 수행하여 얻어진 결과는 다음과 같다. 유채의 종자, 무균배양(無菌培養)된 자엽(子葉), 하배축(下胚軸) 및 엽절편(葉切片)배양에서 명상태에서 보다는 암상태에서 캘러스의 생장이 왕성하였고, 하배축(下胚軸)과 자엽조직(子葉組織)에서 형성된 캘러스에서 shoot 분화능력이 높은 편이었다. 자엽(子葉) 및 하배축(下胚軸) 조직(組織)의 캘러스형성에는 2, 4-D 단용보다 2, 4-D와 kinetin 또는 BAP를 혼용하는 것이 효과적이었으며, 자엽조직(子葉組織)의 경우는 2, 4-D(1.0 mg/)와 0.1mg/의 kinetin이 첨가된 배지에 형성된 캘러스를 0.1mg/의 NAA와 2.0 mg/의 kinetin이 첨가된 배치에 이식하였을 때 shoot 분화율이 16.7%로 가장 높게 나타났다. 하배축(下胚軸) 조직(組織)에서는 1.0mg/의 2, 4-D와 0.5mg/의 kinetin이 첨가된 배지에서 형성된 캘러스를 0.1mg/의 NAA와 4.0mg/의 kinetin이 혼용된 배지에 이식하였을 때 shoot 분화율(分化率)이 24%로 가장 높게 나타났다. 자엽(子葉) 및 하배축(下胚軸) 조직(組織)의 캘러스 형성과 shoot분화능력의 유채 품종간(品種間) 차이는 매우 뚜렷하게 인정되었고, 자엽(子葉)보다는 하배축(下胚軸) 조직(組織)에서 형성된 캘러스에서 shoot 분화능력이 현저히 높게 나타났다.
        4,000원
        1220.
        1992.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study was carried out to find out the effect of dietary intake on cognitive function retardation in old age using dietary survey and cognitive function test. The subjects were 332 men of 50-94 years old and their activities of daily living were very similar. The cognitive function was tested by Mini Mental State Examination (MMSE)-K which was translated from MMSE, and the 24-hour recall method was used for dietary survey. Scoring of MMSE-K was a little different from MMSE, that is, in case of no education, one to four points were added to exclude the effect of education which has been considered as a confounder by many researchers. The number of subjects belonging to below 23 of MMSE-K score was increased by increasing age. Even though points were added in case of no education, the ratio of below 23 MMSE-K score group was diminished by increasing education. Therefore, education seems not to be a confounder but a independent variable on cognitive function. Income, past occupation, family type, self-evaluated health status did not play any effect on cognitive function significantly. On the other hand, the correlation between each nutrients and the score of cognitive function test showed that the more consumption of vitamin A and protein, the higher cognitive function score was obtained. In case of iron and Ca, even though it was not statistically significant, there was a tendency of increasing cognitive function score by increasing the intake of those nutrients. This study suggests that micronutrient intakes might be more related to cognitive function than macronutrients.
        4,000원