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        검색결과 1,248

        181.
        2018.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        We used the upland field rotated from matured rice paddy field, which have been used as a rice paddy field long time, for three years from 2015 to 2017. Therefore, this study was conducted for three main purposes. The first was to investigate yearly changes of growth and yield for waxy maize in the organic farming waxy maize at rice paddy-upland rotation system, the second was to investigate yearly changes of soil physical and chemical characteristics of rice paddy field soil in organic farming waxy maize at rice paddy-upland rotation system and the third was to select the suitable varieties for organic farming waxy maize at rice paddy-upland rotation. The test varieties were that 8 varieties of waxy maize of Mibaek 2, Ilmichal, Daehakchal, Chalok 4, Miheukchal, Eolrukchal 1, Heukjinjuchal, Heugjeom 2. For yearly yield, the highest yield was obtained in the first year of 949.6 kg, the second highest was in the third year of 680.6 kg 10a-1, while the second year was the lowest yield (675.4 kg 10a-1). Both varieties of Chalok 4 and Ilmichal showed the highest yield with about 900 kg 10a-1 in the threeyear average of 8 varieties. Solid phase of deep soil was 10% higher than that of top soil. Porosity rate of the top soil (54.7%) was higher than that of deep soil (49.4%), and the porosity in the third year was 2.7% higher than that of the first year. Soil organic matter content was significant different between soil depths and between three years. Soil solid and liquid phase decreased by 1.6% and 4.3%, respectively, compared to the first year, and the gas phase increased by 4.3%. The porosity of the third year was 2.7% higher than that of the first year. The soil organic matter content was 9.5 g kg-1 in the third year compared with 12 g kg-1 in the first year. It has also trend to decrease as the number of years rotated from rice paddy field increased. In the three-year average yields of Ilmichal and Chalok 4 were 898.1 kg 10a-1 and 891.6 kg 10a-1 respectively and the yield of Chalok 4 was greater than the other 7 varieties. We compared and selected the two best waxy maize varieties of Chalok 4 and Ilmichal for rice paddy-upland rotation. When we look at the yearly variation for waxy maize, Waxy maize yield was the highest in the first year and decreased year by year. Therefore, it would be better to restore upland field to rice paddy fields after the first year.
        4,000원
        182.
        2018.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구에서는 vitamin C를 넣어 발효시킨 오징어 액젓을 조미용도로 활용하기 위해 발효 과정 중 아미노산함량 변화, 염도별 이화학적 특성, 오징어 액젓과 시판 저염간장 과의 관계양상을 파악하였다. 발효 중 총 아미노산은 증가 하였으며, 그중 Asp, Pro, Gly, Ala, Val, Ile, Leu의 함량은 발효 기간에 따라 증가하였다. 소금 첨가량에 따라 오징어 액젓의 염도와 당도는 증가하였으며, 수분과 pH는 감소하는 것으로 나타났다. 색도의 경우 소금을 넣을 경우 명도, 적색도, 황색도 모두 감소하였고, 소금 첨가량에 따른 차이는 있으나 특별한 경향을 보이지는 않았다. 동일한 염도의 오징어 액젓과 시판 저염간장의 관능검사 결과, 색은 모든 염도에서 차이를 보였으며, 향은 1, 2, 4%에서 차이를 보 였다. 짠맛은 염도가 높아질수록 기호도가 높아지는 경향 을 보였다. 오징어 액젓의 단맛은 가장 낮았으며, 신맛은 가장 높은 기호도를 가졌다. 오징어 액젓과 저염간장의 기 호도 양상은 83.84~94.51%의 설명력을 가지며, 향과 색의 기호도는 저염간장보다 오징어 액젓이 높았고, 감칠맛은 반대로 저염간장이 높은 것으로 나타났다. 또한 감칠맛과 단맛은 전반적 기호도와 양의 상관관계를 가지는 것으로 조사되었다. 오징어 액젓의 염도가 높아질수록 저염간장군과 가까워지는 것으로 나타나 일정 염도를 가질 때 간장과 유사한 용도로 사용이 가능할 것으로 보인다.
        4,000원
        183.
        2018.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        코팅, 발수 및 접착특성이 우수한 불소함유 아크릴계 공중합체를 설계, 제조하였다. 공중합체용 모노머로 methyl methacrylate(MMA), 2,2,2-trifluoroethyl acrylate(FMA) 그리고 2-hydroxyethyl methacrylate(HEMA)를 사용하여 괴상 중합 및 유화 중합으로 반응하여 > 95 %이상 고수율로 공중합체를 제조하였다. 1H-NMR로 화학구조를 확인하였고 DSC와 DMA로 물성분석을 한 결과, FMA의 함량이 5 %에서 10 %로 증가함에 따라 유리전이온도는 3 ℃ 감소하였으며 HEMA의 경우에는 감소폭이 2 ~ 8 ℃로 나타났다. Instron 및 TGA를 이용한 분석에서는 FMA 혹은 HEMA 함량이 10 % 증가함에 따라 괴상 및 유화 중합체 모두에서 인장강도는 29 MPa에서 22 MPa로 감소하였고 Td는 200 ℃에서 180 ℃로 감소하는 경향을 나타내었다. 접촉각은 친수성인 HEMA의 함량이 증가함에 따라 상대적으로 감소하였다.
        4,000원
        186.
        2018.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The purpose of this study is to examine the mediating effect of the organizational trust, acceptance of organizational change on the relationship between job characteristics and organizational commitment. For this study, data were collected from convenient sample of 241 employees at small and medium enterprises in Ulsan city and Gyeongju city. All data collected from the survey were analyzed using with SPSS 18.0 and AMOS 18.0. This study reports findings as followed: 1. The relationship between the job characteristics and the organizational trust is positively related. 2. There was a positive correlation between the job characteristics and the acceptance of organizational change. 3. There was a positive correlation between the job characteristics and the organizational commitment. 4. The relationship between the organizational trust and the acceptance of organizational change is positively related. 5. There was a positive correlation between the organizational trust and the organizational commitment. 6. There was a positive correlation between the acceptance of organizational change and the organizational commitment. Finally, the organizational trust and acceptance of organizational change played as a partial mediator on the relationship between job characteristics and organizational commitment.
        4,000원
        187.
        2018.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        PURPOSES : The main purpose of this study is suggest of field bond strength evaluation method for more objective evaluation method through Evaluation of Bond Strength Properties with changing aspect ratio and temperature. METHODS : The evaluation is laboratory bond strength test. Using the core machine, the pull-off test method ; the bond strength test of interface layer the universal testing machine. RESULTS: As a result of the laboratory bond strength evaluation, it was verified that the bond strength by aspect ratio decreases linearly with increasing aspect ratio and the bond strength properties by temperature change existed at high and low temperature condition relative to odinary temperature condition. CONCLUSIONS: According to the results of laboratory bond strength evaluation, the field bond strength evaluation results suggest applying the proposed correction factor (0.8, 1.0, 1.4, 1.9) according to aspect ratio(0.5, 0.1, 1.5, 2.0), For more objective evaluation of the bond strength, it is analyzed that the evaluation value is within 6 ~ 32℃ and the result can be obtained within 5% of the coefficient of variation.
        4,000원
        188.
        2018.05 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Effects of annealing temperature on the microstructure and mechanical properties through thickness of a Cu-3.0Ni- 0.7Si alloy processed by differential speed rolling are investigated in detail. The copper alloy with a thickness of 3 mm is rolled to a 50 % reduction at ambient temperature without lubricant and subsequently annealed for 0.5 h at 200-900 oC. The microstructure of the copper alloy after annealing is different in the thickness direction depending on the amount of the shear and compressive strain introduced by the rolling; the recrystallization occurs first in the upper roll side and center regions which are largely shear-deformed. The complete recrystallization occurs at an annealing temperature of 800 oC. The grain size after the complete recrystallization is finer than that of the conventional rolling. The hardness distribution of the specimens annealed at 500-700 oC is not uniform in the thickness direction due to partial recrystallization. This ununiformity of hardness corresponds well to the amount of shear strain in the thickness direction. The average hardness and ultimate tensile strength has the maximum values of 250 Hv and 450 Mpa, respectively, in the specimen annealed at 400 oC. It is considered that the complex mode of strain introduced by rolling directly affects the microstructure and the mechanical properties of the annealed specimens.
        4,000원
        191.
        2018.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Climate change is believed to increase the amount of dissolved organic matter in surface water, as a result of the release of bulk organic matter, which make difficult to achieve a high quality of drinking water via conventional water treatment techniques. Therefore, the natural water treatment techniques, such as managed aquifer recharge (MAR), can be proposed as a alternative method to improve water quality greatly. Removal of bulk organic matter using managed aquifer recharge system is mainly achieved by biodegradation. Biodegradable dissolved organic carbon (BDOC) and assimilable organic carbon (AOC) can be used as water quality indicators for biological stability of drinking water. In this study, we compared the change of BDOC and AOC with respect to pretreatment methods (i.e., ozone or peroxone). The oxidative pretreatment can transform the recalcitrant organic matter into readily biodegradable one (i.e., BDOC and AOC). We also investigated the differences of organic matter characteristics between BDOC and AOC. We observed the decreases in dissolved organic carbon (DOC) and the tryptophan-like fluorescence intensities. Liquid chromatographic - organic carbon detection (LC-OCD) analysis also showed the reduction of the low molecular weight (LMW) fraction (15% removed, less than 500 Da), which is known to be easily biodegradable, and the biopolymers, high molecular weight fractions (66%). Therefore, BDOC consists of a broad range of organic matter characteristics with respect to molecular weight. In AOC, low molecular weight organic matter and biopolymers fraction was reduced by 11 and 6%, respectively. It confirmed that biodegradation by microorganisms as the main removal mechanism in AOC, while BDOC has biodegradation by microorganism as well as the sorption effects from the sand. O3 and O3 + H2O2 were compared with respect to biological stability and dissolved organic matter characteristics. BDOC and AOC were determined to be about 1.9 times for O3 and about 1.4 times for O3 + H2O2. It was confirmed that O3 enhanced the biodegradability by increasing LMW dissolved organic matter.
        4,000원
        192.
        2018.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study was carried out to determine the optimal storage conditions by examining the effects of the storage conditions on the quality of red pepper powder during storage in households. Red pepper powder was stored at room temperature (20oC), refrigeration (2 and -1oC) and frozen (-5 and -20oC) for 3, 6, 9 and 12 months. The ASTA color value, capsanthin content and redness (a*) of the red pepper powders stored at -5 and -20oC were not decreased significantly depending on the storage temperatures until 9 months. The pH of red pepper powder stored at 20oC decreased significantly until 9 months and increased at 12 months. The microbiological quality of the red pepper powder stored at -5 and -20oC was more stable during long-term storage. In the sensory evaluation of red pepper powder stored under all conditions, the overall freshness, redness, hot flavor, moisture release, and edibility decreased with increasing storage period from the control to 12 months. Moisture release increased from 3 months to 12 months. Overall, red pepper should be stored at low temperatures (2 , -1oC) for up to 6 months, and frozen (≥ -5oC) for 6 to 9 months. The optimal temperature for long-term storage (≥9 months) was -20oC.
        4,000원
        194.
        2018.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        As the number of high-rise buildings increases, a mid-story isolation system has been proposed for high-rise buildings. Due to structural problems, an appropriate isolation layer displacement is required for an isolation system. In this study, the mid-story isolation system was designed and the seismic response of the structure was investigated by varying the yield strength and the horizontal stiffness of the seismic isolation system. To do this, a model with an isolation layer at the bottom of 15th floor of a 20-story building was used as an example structure. Kobe(1995) and Nihonkai-Chubu(1983) earthquake are used as earthquake excitations. The yield strength and the horizontal stiffness of the seismic isolation system were varied to determine the seismic displacement and the story drift ratio of the structure. Based on the analytical results, as the yield strength and horizontal stiffness increase, the displacement of the isolation layer decreases. The story drift ratio decreases and then increases. The displacement of the isolation layer and the story drift ratio are inversely proportional. Increasing the displacement of the isolation layer to reduce the story drift ratio can cause the structure to become unstable. Therefore, an engineer should choose the appropriate yield strength and horizontal stiffness in consideration of the safety and efficiency of the structure when a mid-story isolation system for a high-rise building is designed.
        4,000원
        195.
        2018.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        중부 평야지에서 중생종 벼 하이아미의 이앙시기에 따른 출수기의 변동과 출수 전후의 기상 및 수량 특성을 파악하고 적절한 재배시기를 제안하기 위하여, 이앙시기를 5월 10일부터 6월 24일까지 조절하여 3년간 국립식량과학원 중부작물부 수원 벼 재배시험 포장에서 시험한 결과는 다음과 같다. 1. 이앙기가 늦을수록 출수기까지는 일 평균기온이 높았으나 출수소요일수가 단축됨에 따라 적산온도가 적어졌고, 출수 후 40일간은 평균기온이 낮고 일조시간이 많은 경향이었다. 2. 이앙기~출수기와 출수 후 40일간의 평균기온은 시험연차보다 이앙시기에 따른 변이가 컸으나 일 평균 일조시간은 이앙시기 보다 시험연차에 따른 변이 정도가 더 커서, 이앙시기 조절에 의한 기상요인의 변화는 평균기온에서 뚜렷하게 나타났다. 3. 이앙시기가 늦어짐에 따라 수수는 감소하였으나 수당영화수가 증가하였고, 결과적으로 이앙시기 지연에 의한 출수소요일수의 단축이 sink size의 감소로 이어지지는 않았다. 4. 이앙시기 조절에 의한 m2당 영화수의 변화는 등숙비율과 뚜렷한 상관을 보이지 않았으나, 출수 후 40일간 평균기온이 낮아짐에 따라 현미천립중은 유의하게 증가하는 추세를 보였다. 5. 쌀수량은 이앙시기에 따라 유의차를 보이지 않았던 반면, 완전립 비율은 6월 24일까지 이앙이 늦어짐에 따라 높아지는 추세를 보였으며 그에 따라 완전미 수량도 비슷한 경향을 보였다. 6. 결과적으로, 중부 평야지에서 하이아미는 이앙시기를 6월 중~하순으로 늦춤으로써 쌀 품위를 높이고 완전미 수량을 향상시킬 수 있는 것으로 분석되었는데, 등숙 후기의 저온 피해 우려를 고려하면 6월 중순에 이앙하는 것이 안전할 것으로 판단된다.
        4,000원
        196.
        2018.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The change of quality and physicochemical characteristics of mung-bean flours after germination and roasting treatment were evaluated. The moisture content of the roasted mung-bean flours decreased significantly according to the roasting temperatures and times, and the crude ash, protein and fat contents increased. The lightness of the roasted mung-bean flours significantly decreased, and the redness and yellowness increased. The water binding capacity of the roasted mung-bean flours without and with germination were 151.71 and 192.77% at 240℃ for 20 min, respectively. The water solubility index and swelling power decreased with an increase in roasting temperatures and times. The phenolic compounds and radical scavenging activity of the roasted mung-bean flours increased with an increase in the roasting temperatures and times. The total polyphenol contents of the roasted mung-bean flours without and with germination were 4.81~7.71 and 4.22~5.63 mg GAE/g, and the total flavonoid contents were 2.46~3.05 and 2.45~2.87 mg CE/g, respectively. The DPPH radical scavenging activity of the roasted mung-bean flours, without and with germination, were 106.83~376.08 and 174.41~346.70 mg TE/100 g, and the ABTS radical scavenging activity was 251.67~534.31 and 274.39~430.02 mg TE/100 g, respectively. As a result, it is necessary to set quality standards for each application considering the quality and antioxidant properties of the roasted mung-bean flours.
        4,200원
        197.
        2018.02 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Effects of annealing temperature on the microstructure and mechanical properties through thickness of a cold-rolled Cu-3.0Ni-0.7Si alloy were investigated in detail. The copper alloy with thickness of 3 mm was rolled to 50 % reduction at ambient temperature without lubricant and subsequently annealed for 0.5h at 200~900 oC. The microstructure of the copper alloy after annealing was different in thickness direction depending on an amount of the shear and compressive strain introduced by rolling; the recrystallization occurred first in surface regions shear-deformed largely. The hardness distribution of the specimens annealed at 500~700 oC was not uniform in thickness direction due to partial recrystallization. This ununiformity of hardness corresponded well with an amount of shear strain in thickness direction. The average hardness and ultimate tensile strength showed the maximum values of 250Hv and 450MPa in specimen annealed at 400 oC, respectively. It is considered that the complex mode of strain introduced by rolling effected directly on the microstructure and the mechanical properties of the annealed specimens.
        4,000원
        198.
        2018.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study investigated the effect of various freezing and thawing conditions on the quality characteristics of radish. White radish was blanched and cooled down to corresponding freezing temperatures of -20℃, -40℃ and -60℃ and, thereafter, the radish was finally frozen in a -20℃ refrigerator for 24 h. The frozen radish was thawed at 4℃, 25℃ and with running water, radio-frequency thawing machine. As quality parameters, pH, drip loss, hardness, color, and sensory evaluation were evaluated. No effect of freezing and thawing conditions on color, pH, and total bacterial count was observed for the samples. Samples that underwent immersion freezing (-60℃) had lower drip loss and higher hardness than samples in other freezing conditions. Sensory evaluation showed that color, hardness, and overall acceptability increased with a decrease in freezing temperature. These results indicate that the temperature of freezing affects the quality of radish.
        4,000원
        199.
        2018.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study was conducted to investigate the quality of pumpkin paste added with different starches during storage at 4℃ for 8 days. Pumpkin paste was evaluated for pH, carotenoid, syneresis, color values, texture, and sensory characteristics. The properties of the pumpkin paste were studied on three different starches (CON: control, MCP: cow pea starch, MMB: mung bean starch, and MSP: sweet potato starch). The initial pH of the pumpkin paste with starches were 6.13~6.16. The pH of pumpkin paste increased as the starches added increased. The carotenoid content of CON was higher in the pumpkin paste processing. The change of syneresis significantly increased with the storage period, and the amount of change of MCP and MMB added with starch was smaller than CON without the added starch. The Hunter's L-values of the pumpkin paste increased, whereas the a- and b-value decreased as the amount of starches added increased. The results of the textural analysis showed that the hardness of MCP and MMB was different from that of other pumpkin paste, showing a lower value such as 38.26 g, 38.93 g, while CON and MSP was 40.43 g and 42.49 g, respectively. A sensory evaluation indicated that starches could enhance the overall texture characteristics of pumpkin paste. In terms of the overall acceptance of the pumpkin paste, the experimental group with MCP scored the best.
        4,000원
        200.
        2017.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        석유제품은 다양한 형태의 탄화수소화합물로 구성되어진 화합물로, 다른 종류의 액체류와 마찬가지로 온도변화에 따른 밀도와 부피의 변화가 발생한다. 액상에서 석유제품의 밀도를 측정하는 방법은 분별 증류된 각 석유제품에 대해 주로 얻어진 실험 데이터를 기반으로 한다. 본 연구에서는 등유와 자동차용 경유의 온도변화에 따른 밀도와 부피변화를 실제 측정하여 온도변화에 따른 변화추이를 분석하고, 국제규격인 ASTM에서 제시하는 밀도부피 환산표를 이용한 환산값을 계산하고 두 값을 비교분석하였다. 또한, 국내 계량 관련법에서 규정하고 있는 온도변화에 대한 기준과 실측값과의 상호 비교를 통해 차이점을 분석하였다.
        4,000원