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        검색결과 348

        161.
        2008.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        4,000원
        163.
        2008.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, the recovery rate of thermal desorbing (TD) method was investigated in relation to sample concentration and loading volume of reduced sulfur compounds (RSC). All the analysis of RSC was made by gas chromatography/pulsed flame photometric detector (GC/PFPD) combined with air server/thermal desorber (AS/TD). The RSC measurement data were obtained by loading gaseous RSC standards prepared at 4 concentrations (10, 20, 50, 100 ppb) at 6 injection volumes (40, 80, 200, 400, 800, and 1200 mL). The recovery rates of each RSC were computed in terms of relationship between expected vs. measured values. According to our analysis, the following conclusions can be drawn. First, the results were less stable at short loading time (1 and 2 min at 40 mL/min) with reduced recovery rate, especially with light RSCs (H₂S and CH₃SH). On the other hand, at sufficiently high loading volume, their quantification was limited by off-scale peaks (at a near 50 ng) due to the breakthrough of cold trap in TD. Thus, the optimization of TD-based analysis may be considered as a prerequisite for analyzing the RSC in a reliable manner.
        4,000원
        164.
        2008.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        트럭 축하중에 의한 도로포장체의 응력과 변형은 대부분 다층 탄성 이론에 의해 예측된다. 대부분의 다층 탄성 이론에 의한 이론적 계산값이 연성 포장 재료의 점탄성적 거동특성, 동적 트럭 축하중, 비균등 타이어 접지압 및 형상등을 해석에 고려하지 못하므로, 계측값에 비해 매우 작은 값을 예측하므로서 도로 포장 두께설계가 과소 설계될 우려가 크다. 이와 같은 도로 포장체 구조해석시 이용되는 중요한 변동요소를 포장 재료의 물성 모델 측면, 비균등 접지압 및 형상 측면, 동적 유한요소해석 측면에서 분석하여 이용 가능한 모델을 본 논문에서 제안하였다. 경계조건 및 민감도 분석을 수행을 통한 효과적인 3차원 연성포장의 유한요소해석모델을 결정하는 방법론을 제안하였으며, 최적 유한요소모델 분석결과와 현장에서 취득한 결과와의 상호비교를 통하여 모델의 유의성을 검증하였으며, 동적 접지하중조건, 점탄성물성 모델 등을 3차원 유한요소 모델에 접목하고, 최적 경계조건을 결정하였다.
        4,300원
        165.
        2008.11 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The snow melting system by electric heating wires which is adopted in this research is a part of road facilities to keep surface temperature of the road higher than freezing point of water for melting the snow accumulated on it. The electric heating wires are buried under paved road at a certain depth and operated automatically and manually. Design theory, amount of heating, and installation standard vary according to economic situation, weather condition, installation place and each country applying the system. A main purpose of this study is figuring out the appropriate range of required heat capacity and installation depth and pitch for solving snowdrifts and freezing problems with minimum electric power consumption. This study was performed under the ambient air temperature(-2℃, -5℃), the pitches of the electric heating wires(200 mm, 300 mm), heating value(250 W/m2, 300 W/m2, 350 W/m2).
        4,000원
        167.
        2008.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The principal objective of this study was to develop the optimal recipe for muffins containing dried broccoli powder. In this study, broccoli powder was substituted for wheat flour in order to reduce its content. The study was conducted by determining the optimal sensory composite recipe, by preparing muffins with different levels of broccoli powder (A), sugar (B), and butter (C), by C.C.D (Central composite design) and performing sensory evaluation and analysis via RSM (Response surface methodology). The sensory measurements yielded significant values for appearance, flavor (p<0.01), texture (p<0.05), overall quality (p<0.05) and color (p<0.05), whereas instrumental measurements yielded significant values in lightness (p<0.01), redness (p<0.05), yellowness, baking loss rate (p<0.05), hardness (p<0.05), cohesiveness (p<0.01) and gumminess (p<0.05). The optimum formulations processed by numerical and graphical optimization were determined as 13.58g of broccoli powder, 92.02g of sugar, and 71.97g of butter.
        4,000원
        168.
        2008.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The purpose of the present study is to investigate the optimal wavelength, frequency and energy density for set up the photobiologic treatment of periodontal disease. To establish the present study, λ scan of 500㎚ to 900㎚ was used to search the optimal wavelength for maximal proliferation of human gingival fibroblasts. Cell proliferation assay was carried out as MTT assay. Light intensity of 0.8 to 3.25mW, frequency of 0 to 584㎐ and 0 to 2hours was applied for investigation of optimal energy density, frequency and applied duration. Finally, 628㎚ with 1mW/cm2 for 1hour of LED irradiation resulted in maximal proliferation of gingival fibroblasts. These results suggest that LED irradiation on gingival fibroblast show different proliferation according to the condition of irradiation, and demonstrate that LED irradiation can control the quantity of cell proliferation.
        4,000원
        171.
        2008.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This purpose of this study was to develop a functional muffin by adding yam powder in the shape of a muffin as a partial surrogate for wheat flour. The yam has been found to be effective for liver and kidney function, as well as the digestion of protein, since it produces glucuronic acid in the body. Therefore, the purpose of this study was to determine the optimal mixing conditions of yam muffins by adjusting the amounts yam powder, butter, and sugar. The mixing conditions for the yam muffins included 3 categories: yam powder (X1), sugar (X2), and butter (X3) by Central Composite Design (CCD) which was optimized by Response Surface Methodology (RSM). The effects of the three variable additions on muffin quality were examined via physical and chemical experiments, such as the analysis of texture (hardness, cohesiveness, springiness, gumminess), coloration (lightness, redness, yellowness), and height. Lastly, we performed a sensory test, which revealed significant findings for gumminess, color, appearance, flavor, softness (p〈0.05), redness, and overall quality (p〈0.01). Consequently, the optimal mixing rate which best satisfied the sensory items were 34.35g of yam powder, 80.15 g of sugar, and 80.55 g of butter.
        4,000원
        172.
        2007.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study was carried out to develop and characterize a drinking extract of disk abalone to keep the price level and to raise a added value of disk abalone. Fresh raw disk abalone was composed of 29.3% of the shell part, 17.7% of the intestinal part, and 43.9% of the flesh part. and the amount of nutritive substances in the intestinal part were higher those in the flesh part. Arginine was the most abundant amino acid both in raw and drinking extract of disk abalone. Drinking extract prepared with 250 g of the flesh of disk abalone at 100℃ for 2 hours was better in color and overall taste than those made with 150 g or 200 g of the flesh. As the extracting temperature was gradually increased or the extracting period was gradually extended, the extracting effect was slightly improved but the color of the extract turned out to undesirable one. The desirable sea tangle extract could be made when 15 g of sea tangle was extracted in 1 l of water at 100℃ for 2 hours, and which was accorded well with the color of drinking abalone extract. From these results the best drinking extract of disk abalone can be manufactured with 250 g of the abalone flesh extracted in 1 l of water at 100℃ for 2 hours.
        4,000원
        173.
        2007.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        새로운 항균물질의 탐색이 활발하다. 선행연구에서 새로운 항균활성물질을 생산하는 세균이 한국토양에서 분리되어 Paenibacillus polymyxa DY1으로 동정 및 명명되었으며, 다제내성 장내세균들에 대한 항균활성 특성이 규명되어 새로운 항생물질로서 잠재력을 보여주었다. 본 연구에서 배지의 탄소원, 무기질소원, 유기질소원, 아미노산, 무기염류 등의 영양 조성물과 물리화학적 생장조건이 P. polymyxa DY1 균체의 생장과 항균활성 생산에 미치는
        4,000원
        174.
        2007.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 온시디움에 있어서 particle bombardment 및 아그로박테리움 매개 형질전환 최적 조건을 구명하 고자 실시하였다. 실험재료는 ‘Sharry Baby’의 PLBs를 사용하였으며, 유전자는 pCAMBIA3301 vector에 삽입 되어 있는 bar와 intron-gus를 사용하였다. Particle bombardment 법에 있어서는 직경이 0.6 μm인 금 입자 에 유전자를 혼합하여 9 cm의 거리에서 1,100 psi 헬륨 가스 압으로 발사하는 것이 유전자 도입에 효과적이었 다. 아그로박테리움 매개법에 있어서는 미성숙 PLBs를 O.D 0.6 정도인 균주에 접종 후 5일간 광조건 없이 공동 배양하는 것이 유전자 도입에 효과적이었다.
        4,000원
        175.
        2007.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        호접란 조직배양시 발생하는 체세포변이의 발생을 줄 이기 위한 적절한 다신초 유기배양 조건과 계대배양 조 건에 관한 연구를 실시하였다. 다신초 유기 및 증식의 적 정 배지로서는 1/2 MS 배지가 VW 배지와 Hyponex 배 지보다 더 효율적이었다. 다신초 유기에 적절한 생장조 절제 농도는 BA 5mg · L-1와 TDZ 1mg · L-1가 적절하였 다. 계대 배양의 횟수가 증가할수록 기형 신초수의 발생 이 증가하였다. 그러나 2개월마다 3회 계대배양할 때까 지는 기형 신초가 거의 발생하지 않았다. 특히 핑크계 호 접란 품종에서 6회 이상 계대할 경우 기형 신초 발생율 이 30%에 육박하였고 배지내 페놀 물질의 집적이 더 많 이 관찰되었다. 식물체를 배지에 치상한 후 2개월이 지 나 처음으로 계대 배양하였을 때 모든 품종에서 기형 신 초 발생이 거의 없었지만, 이후 계대배양 기간이 증가함 에 따라 기형 신초 발생율과 고사율이 증가하였다. 그러 므로 적어도 2개월에 한 번씩 계대 배양하는 것이 바람 직한 것으로 판단되었다.
        4,000원
        178.
        2006.09 구독 인증기관 무료, 개인회원 유료
        In this study, numerical analysis of TMD to estimate optimal-design-parameter is investigated using actual excitation, and evaluated by comparing results of numerical analysis and optimal-design-parameter was devised by Soong. It assumed between 1~2 seconds the 1st mode natural period of an aged apartment which has 10~15 stories and then investigated optimal-design-parameter of actual excitation for evaluate optimal frequency ratio and damping ratio according to local site condition. At this time mass ratio was 1% and range of tuned frequency ratio was 0.8Hz to 1.2Hz at intervals of 0.01Hz, and optimal damping ratio was 1% to 14% at intervals of 0.002%. It estimated Optimal-design-parameter was evaluated by numerical analysis according to peak and RMS displacement, acceleration respectively local site. And the result of evaluated respond performance parameter respectively a period was shown low numerical-value than optimal-design-parameter was devised by Soong what is more peak acceleration indicated performance difference of 20% over
        4,000원
        180.
        2005.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In general, water treatment sludge (WTS) had high concentration of heavy metal, thus it made the reuse or recycling of WTS difficult. The optimal solidification conditions for maximum suppression of heavy metal elution from WTS were decided in this study. Under the optimal solidification conditions (i.e., temperature, 320℃; ratio of WTS and MgO, 9:1; solidification time, 1hr), all of heavy metal including aluminum were not detected. Therefore there are no problems for reuse or recycling of WTS which was solidified under the optimal solidification conditions found in the study.
        4,000원