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        검색결과 220

        61.
        2016.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        디젤엔진에서는 2차 분사 시스템은 다양한 배기 시스템에 적용이 가능하고, 엔진 제어와 관계없이 독립적으로 제어가 가능하기 때문에 환원제 희석 면에서도 후분사 또는 다른 농후한 환원제 분위기 형성 방법 등에 비해 장점이 많다. 2차 분사 시스템에서는 환원제의 공급 방법에 따라서 촉매의 효율은 달라질 수밖에 없다. 환원제는 일정압력 이상으로 유지 및 최적화가 필요하고, 인젝터의 위치 및 각도의 선정은 매우 중요한 인자이다. 본 논문에서는 2차 분사 조건을 변화시켜 환원제의 농도와 양을 변화시켰다. De-NOx 촉매 시스템에서 최대의 NOx 정화 효율에 적합한 환원제 분사 조건들의 선정이 필요하고, 분무 도달거리, 분무 평균 입경, 분무각, 분사량 등의 분무 특성과 환원제의 균일 분포를 잘 파악하여야 한다. 이와 같은 목적을 위하여 2차 분사에서 충돌판 형상에 의한 분무 및 거동 특성은 가시화 방법과 디지털 화상 처리 기법을 사용하여 분석하였으며, 충돌판 형상의 영향성과 각 형상에 대한 최적 각도 범위를 도출하였다.
        4,000원
        62.
        2016.10 구독 인증기관·개인회원 무료
        White rice with grains is a nutritious meal that richly contains fiber, vitamin and mineral, but it is difficult for elderly people to masticate some grains and beans due to its hardness. This study was aimed to find the optimal mixing ratio of rice with texture modified grains and beans by comparing rheological properties. Beans were soaked in tap water for 24 hr at 20°C, cooked under pressure (1hr at 121°C), frozen for 24 hr at -18°C, and thawed in water bath for three hr at 30°C. The samples were submerged in macerating enzyme solution, left under vacuum at 60 mmHg for 5 min to infuse the enzyme into the intercellular spaces of samples, and rapidly returned to the atmospheric pressure. The samples were removed from enzyme solution, sealed in plastic bag, placed at 70°C for 20 min for enzyme activation and inactivated at 95°C for 15 min. The grains and texture modified beans were added to white rice with different ratio, soaked for one hr in enzyme solution under warming condition at 70°C, and steamed with electric pressure cooker. Cooked meals were rapidly cooled at -18°C for one hr, placed at 20°C for another one hr, and then rheological properties were measured with texture analyzer. The hardness of texture modified rice with grains was reduced to 2.3 ~ 4.1 × 104 N/m2 and the hardness of rice with beans was reduced to 3.8 ~ 4.8 × 104 N/m2 depending on mixing ratio. The cohesiveness was reduced by 1/3 ~ 2/3 respectively, while adhesiveness was not changed significantly, compared to those of cooked rice. These results suggest that cooked rice mixed with 30 ~ 40% of grain and 6 ~ 10% of bean would be appropriate for elderly people to consume without chewing difficulty.
        63.
        2016.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, the mixing method of positive paste and mixing temperature to improve the capacity of the lead-acid batteries has been investigated. The results show that the initial current capacity of lead acid battery depend on the mixing temperature and mixing method of positive paste. In the results of the capacity cycle repetition tests for estimating the life cycle, the 3BS showed the PCL. but the fine 4BS represented certain improved cycles compared to that of the coarse 4BS. It was considered that the fine 4BS showed higher bond strength between active materials than the coarse 4BS and represented large contact areas and that lead to prevent possible sulfation due to the suppression of insulating layers.
        4,000원
        64.
        2016.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The MLCC electronic materials are used to make many industrial parts, for instance, such as smart phone, radio, LCD TV and so on. The screen ways and the rotor ways are known as methods that form electrode in MLCC. In these days, rotor ways have been frequently utilized because of its stability of quality. In this study, mixing characteristics for the inside of barrel of planetary mixer driver were investigated by numerical analysis using k-ε model of unsteady state, including effects for rotation and revolution. As the results, it showed that the flow of radius direction was mixed with regular pattern depending on time, however, the flow of longitudinal direction was mixed with same pattern regardless of time.
        4,000원
        65.
        2016.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        음식물류폐기물의 에너지 잠재량은 2,206 천TOE 임에도 대부분 사료화와 퇴비화로 약 85.5%가 재활용 되고 있으며, 해당 시설에서 생산된 제품 중 사료화는 72%, 퇴비화는 61%가 무상판매 되고 있다. 이에 본 연구는 음식물류폐기물을 반탄화 반응을 이용하여 연료화하고자 한다. 하지만 음식 물류폐기물만 단독으로 연료화 할 경우 연료적 가치가 낮아짐을 예방하고자 하수슬러지를 일정 비율로 혼합하여 진행하였다. 음식물류폐기물과 하수슬러지의 혼합비율은 10:0, 8:2, 6:4, 5:5로 하였다. 실험 결과 혼합 비율에 상관없이 반응온도 240℃이상에서 함수율 10% 이하로 감소하는 것을 확인 할 수 있 었다. 고정탄소의 경우 반응온도가 높아질수록, 하수슬러지의 비율이 높아질수록 증가하였으며, 초기 1.1%에서 최대 약 36% 로(혼합비율 6:4, 반응온도 270℃) 측정 되었으며, 발열량의 경우 반응온도 24 0℃부터 고형연료제품기준인 3,000Kcal/Kg 이상에 만족하는 발열량을 나타내었으며, 초기시료보다 약 6 배 정도 증가한 발열량을 얻을 수 있었다. Van krevelen Diagram이 Lignite 범위까지 이동하였으며, 슬 러지 혼합비율이 높아질수록 높은 연료비와 5,500Kcal/kg 이하의 연소성지수를 얻을 수 있었다. 하수슬 러지 혼합 비율이 높아질수록 발열량은 감소하지만, 고정탄소 함량 증가, 연료비 개선 등으로 음식물류 폐기물만 단독 고형연료화 한 것 보다 연료로써의 품질이 좋아지는 것을 확인 할 수 있었다.
        4,000원
        66.
        2016.05 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The purpose of this study was to formulate the optimal ratio of tofu ice cream made with crushed tofu and soybean milk. Also, to compare characteristics of tofu ice cream and soybean ice cream. Mix viscosity, overrun and melting down are measured as characteristics of ice cream. The optimal mixing ratio of tofu ice cream was determined by response surface methodology based on overall quality. As a result of optimization, tofu ice cream was made with 65.90% tofu cream (9% solid contents), 4.35% whipping cream, 14.35% canola oil, 15.00% sugar, 0.2% emulsifier and 0.2% guar gum. Soybean ice cream made with three different treated (blanched, steamed, roasted) soybean and each preprocess are treated for 0-20 min. Mix viscosity was enhanced preprocessing time increasing. Also, overrun and melting down was decline preprocessing time increased. As a result of comparison of ice cream overall quality, 15 min roasted soybean ice cream was shown the best quality.
        4,000원
        67.
        2016.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The flow acting on a confined jet flow can be represented as a conventional turbulence flow with its complex phase and characteristics. This is still effectively applied in a variety of industries, for example in ejectors. In this study coaxial confined model made of transparent acrylic pipe and driving water nozzle in order to figure out of recirculation flow near the wall of pipe and prove how flow in the pipe can be developed. It was revealed that length of the recirculation flow adjacent to wall of pipe was characterized to be larger when Reynolds Number is getting bigger.
        4,000원
        68.
        2015.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The effects of mixing speed (3, 6 and 10 speed) and time (2, 5 and 10 min) on the dynamic viscoelasticity of dough and the baking properties of gluten-free rice bread were investigated. The specific gravity of the dough was not affected by the mixing speed and time before and after fermentation. The elasticity (G') and viscosity (G") of the dough increased and the tan δ (G"/G') decreased with higher mixing speeds and longer mixing times. The specific volume of the gluten-free rice bread was affected by the mixing time in response surface methodology (RSM). The hardness of the gluten-free rice bread showed a decreasing trend as the specific volume for the gluten-free rice bread increased. The appearance of the gluten-free rice bread was symmetrical at high mixing speeds and long mixing times. Overall results indicated that the quality of gluten-free rice bread could be improved by controlling the mixing speeds and mixing times for the dough.
        4,000원
        69.
        2015.11 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The purpose of this study was to formulate the optimal mixing ratio for Korean vinegared cabbages harvested in fall from Haenam, Hongseong and Gyeongsan regions. The general compositions such as moisture and ash, and hardness were not significant different among 3 cabbages. The vinegared cabbage was made with vinegar, salt and sugar, and stored at 5oC for 5 d. The diffusion of salt, sugar and vinegar to the cabbage was completed within 3 h. The optimal mixing ratio of those components was determined by response surface methodology (RSM) based on overall preference. As a result of analysis, optimal mixing ratio of Haenam vinegared cabbage was 8.94% vinegar, 1.88% salt, and 18.18% sugar, whereas 8.91% vinegar, 2.12% salt, and 17.97% sugar in Hongseong vinegared cabbage, lastly 8.24% vinegar, 2.50% salt, and 18.26% sugar in Gyeongsan vinegared cabbage. Storage characteristics were investigated at different storage times and temperatures using overall preference, texture, and pH. Overall preference and texture were enhanced after 1 wk storage, but vinegared cabbage was spoiled after 3 wk at 20oC. Change in pH was the fastest during 1 wk at all temperatures, and then reached equilibrium.
        4,000원
        70.
        2015.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        PURPOSES : This study was conducted to derive the optimum mixing ratio of phosphorescent pigment for the development of phosphorescent line marking. METHODS: In this study, we utilized a literature review and case study methodology, to describe the domestic and foreign state of practice for the production and mixing of phosphorescent pigment for use in line marking. The optimal mixing ratio was derived by comparing the reduction in luminance over time for the various phosphorescent pigment mixing ratios identified in the literature. In addition, performance and construction characteristics were analyzed using field testing techniques. RESULTS : The results were as follows: 1) the results of the luminance performance standards tests showed that all of the phosphorescence test specimens satisfied the phosphorescent fire protection standard. As the phosphorescent pigment mixing ratio increased, the luminance value increased, 2) the luminance reduction rate was minimum at the mixing ratio of 50%. However, when compared to a mixing ratio 40%, a small difference was recorded, the luminance reduction rate from the mixing ratio of 40% is judged as being converged. Therefore, in view of the economic efficiency, it was determined that the optimal mixing ratio was 40%, 3) as a result of construction on the field, a mixing ratio of 40% was found to have a higher luminance value than the general line marking for up to three hours after sunset, 4) it was found that the phosphorescent line markings without glass beads spraying had a higher luminance value than the phosphorescent line markings with glass beads spraying. CONCLUSIONS : Through the results of the basic experiments of the line markings obtained by blending a phosphorescent pigment, the results could be applied to play an important role in the development of phosphorescent line marking paint technology and in establishing application planning for on-site construction characteristics.
        4,000원
        71.
        2015.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The synthesis of NiTi alloy powders by hydrogen reduction and dehydrogenation process of NiO and TiH2 powder mixtures is investigated. Mixtures of NiO and TiH2 powders are prepared by simple mixing for 1 h or ball milling for 24 h. Simple-mixed mixture shows that fine NiO particles are homogeneously coated on the surface of TiH2 powders, whereas ball milled one exhibits the morphology with mixing of fine NiO and TiH2 particles. Thermogravimetric analysis in hydrogen atmosphere reveals that the NiO and TiH2 phase are changed to metallic Ni and Ti in the temperature range of 260 to 290oC and 553 to 639oC, respectively. In the simple-mixed powders by heat-up to 700oC, agglomerates with solid particles and solidified liquid phase are observed, and the size of agglomerates is increased at 1000oC. From the XRD analysis, the presence of liquid phase is explained by the formation and melting of NiTi2 intermetallic compound due to an exothermic reaction between Ni and Ti. The simple-mixed powders, heated to 1000oC, lead to the formation of NiTi phase but additional Ni-, Ti-rich and Ti-oxide phases. In contrast, the microstructure of ball-milled powders is characterized by the neck-grown particles, forming Ni3Ti, Ti-oxide and unreacted Ni phase.
        4,000원
        72.
        2015.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        PURPOSES : Recently, bonded concrete overlay has been used as an alternative solution in concrete pavement rehabilitation since its material properties are similar to those of the existing concrete pavements. Deteriorated concrete pavements need rapid rehabilitation in order to prevent traffic jams on Korean expressways. Moreover, speedy and effective repair methods are required. Therefore, the use of bonded concrete overlay with ultra-rapid hardening cement has increased in an effort to reopen promptly the expressways in Korea. However, mobile mixer is required for ultra-rapid hardening cement concrete mixing in the construction site. The use of mobile mixer causes various disadvantages aforementioned such as limitation of the construction supply, open-air storage of mixing materials, increase in construction cost, and etc. In this study, therefore, hydration accelerator in-situ mixing on polymer modified concrete produced in concrete plant is attempted in order to avoid the disadvantages of existing bonded concrete overlay method using ultra-rapid hardening cement. METHODS: Bonded concrete overlay materials using ultra-rapid hardening cement should be meet all the requirements including structural characteristics, compatibility, durability for field application. Therefore, This study aimed to evaluate the application of hydration accelerator in-situ mixing on polymer modified concrete by evaluating structural characteristics, compatibility, durability and economic efficiency for bonded concrete overlay. RESULTS : Test results of structural characteristics showed that the compressive, flexural strength and bond strength were exceed 21MPa, 3.15MPa and 1.4MPa, respectively, which are the target strengths of four hours age for the purpose of prompt traffic reopening. In addition, tests of compatibility, such as drying shrinkage, coefficient of thermal expansion and modulus of elasticity, and durability (chloride ions penetration resistance, freezing-thawing resistance, scaling resistance, abrasion resistance and crack resistance), showed that the hydration accelerator in-situ mixing on polymer modified concrete were satisfied the required criteria. CONCLUSIONS: It was known that the hydration accelerator in-situ mixing on polymer modified concrete overlay method was applicable for bonded concrete overlay and was a good alternative method to substitute the existing bonded concrete overlay method since structural characteristics, compatibility, durability were satisfied the criteria and its economic efficiency was excellent compare to the existing bonded concrete overlay methods.
        4,200원
        73.
        2015.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Multi-walled carbon nanotube (MWCNT)/polycarbonate (PC) nanocomposite was prepared by direct melt mixing to investigate the effect of the shear rate on the surface resistivity of the nanocomposites. In this study, an experiment was carried out to observe the shear induced orientation of the MWCNT in the polymer matrix using a very simple melt flow indexer with various loads. The compression-molded, should be eliminated. MWCNT/PC nanocomposite sample exhibited lower percolation thresholds (at 0.8 vol%) and higher electrical conductivity values than those of samples extruded by capillary and injection molding. Shear induced orientation of MWCNT was observed via scanning electron microscopy, in the direction of flow in a PC matrix during the extrusion process. The surface resistivity rose with increasing shear rate, because of the breakdown of the network junctions between MWCNTs. For real applications such as injection molding and the extrusion process, the amount of the MWCNT in the composite should be carefully selected to adjust the electrical conductivity.
        4,000원
        74.
        2015.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The present experimental study investigates single-phase heat transfer coefficients downstream of support grid in 6×6 rod bundles. Support grid with Split mixing vanes enhance heat transfer in rod bundles by generating turbulence but this turbulence is confined to a short distance. Support grid with large scale vortex flow(LSVF) mixing vanes enhanced heat transfer to a longer distance. In this study, the experiments were performed at reynolds numbers of 50,000. The characteristics of the heat transfer enhancement of the Split mixing vane and those of the LSVF mixing vane were compared. The results showed that the characteristics of the heat transfer enhancement of rods by the Split mixing vane were limited to 10 Dh after the spacer grid, but those by the LSVF mixing vane were maintained until 15 Dh after the spacer grid. For the reynolds number of 50,000, the heat transfer enhancement effect was 3.0% greater when using the LSVF mixing vane than when using the Split mixing vane between the 1 ∼ 15 Dh interval after the spacer grid.
        4,000원
        75.
        2015.03 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        The effects of the mixing of an active material and a conductive additive on the electrochemical performance of an electric double layer capacitor (EDLC) electrode were investigated. Coin-type EDLC cells with an organic electrolyte were fabricated using the electrode samples with different ball-milling times for the mixing of an active material and a conductive additive. The ball-milling time had a strong influence on the electrochemical performance of the EDLC electrode. The homogeneous mixing of the active material and the conductive additive by ball-milling was very important to obtain an efficient EDLC electrode. However, an EDLC electrode with an excessive ball-milling time displayed low electrical conductivity due to the characteristic change of a conductive additive, leading to poor electrochemical performance. The mixing of an active material and a conductive additive played a crucial role in determining the electrochemical performance of EDLC electrode. The optimal ball-milling time contributed to a homogeneous mixing of an active material and a conductive additive, leading to good electrochemical performance of the EDLC electrode.
        4,000원
        76.
        2014.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구에서는 메탄 대향류 확산 화염내 탄소나노튜브의 합성에 대하여 실험 및 수치적 연구를 수행하였다. 아세틸렌을 일정비율로 메탄에 혼합하여 연료 가스로 사용하였으며, 탄소나노튜브의 합성을 위한 촉매로서 페로센이 이용되었다. 주요 인자로는 메탄 연료에 대한 아세틸렌의 혼합비율이며, 2 %, 6 %, 10 %로 혼합하였다. 탄소나노튜브를 채취한 그리드 위의 탄소나노튜브 합성 특성은 SEM 이미지로 분석되었다. 수치해석에서 화학반응 메카니즘으로는 GRI-Mech 3.0 이 적용되었다. 수치결과로는 아세틸렌 혼합 비율이 증가할수록 화염 온도도 증가하며 CO 몰분율도 증가하는 것을 알 수 있다. 실험결과로는 2% 아세틸렌 혼합 화염이 6 % 및 10 % 혼합 화염과 비교해 탄소나노튜브 합성이 잘 이루어졌음을 알 수 있었다. 이것은 6 % 및 10 % 아세틸렌 혼합화염의 경우 과도한 카본 소스의 생성이 발생해 오히려 화염 내 카본소스가 촉매입자로의 공급을 방해하기 때문이라 생각한다. 이 결과로부터 양호한 질의 탄소나노튜브 생성을 위해서는 적정한 양의 카본소스가 생성되어야 한다는 것을 알 수 있었다.
        4,000원
        77.
        2014.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 옥수수 사일리지를 이용하여 TMR 제조 시 배합시간에 따른 물리적 특성(Particle size, peNDF 및 laceration)의 변화를 조사하고, 반추위 내 in situ 건물분해율 및 비유중기 착유우의 유생산성에 미치는 영향을 조사하고자 수행되었다. TMR 시험사료는 동일한 원료를 이용하여 배합시간을 30분(T1구)과 50분(T2구)으로 제조하였다. Penn State Particle Size Separator (PSPS, 19 mm와 8mm 체)로 분리하여 입자크기의 분포를 분석한 결과 배합 시간이 30분(T1)에서 50분(T2)로 증가함에 따라 하층(<8mm)의 비율이 유의적으로 증가하였고(p<0.01), peNDF>8.0는 유의적으로 감소하였으며(p<0.01), 굵은 비율(≥1mm) 이 유의적으로 감소하였다(p<0.01). 반추위 내 in situ 건물 분해율은 모든 배양시간에서 처리구간 차이가 없었지만 24시간 배양에서 T1구에서 유의적으로 높게 나타났다. (p<0.01). 산유량은 처리구간 차이가 없었지만 유지방은 T1이 유의적으로 높게 나타났다(p<0.01). 본 연구 결과에서 옥수수 사일리지 위주의 TMR 제조 시 배합시간을 단축 조절함으로서 산유량 및 유성분에 대한 부정적 영향 없이 조사료의 물리적 사료가치를 증진하는데 효과가 있을 것으로 기대된다.
        4,000원
        78.
        2014.11 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The objectives of this study were to evaluate the antimicrobial effects of ε-poly-L-lysine mixture (EPM) on cheon-ggukjang and to determine the optimal mixing ratio in cheonggukjang. Increasing the EPM up to 2% decreased via-ble cell counts at both 15oC and 30oC storage. The pH of cheonggukjang without EPM increased slowly over thestorage periods, but cheonggukjang with EPM showed a slight increasing tendency, with the highest pH at 2% EPM.The sensory scores, such as texture and flavor, were highest in samples containing 2% EPM; however, overall pref-erence was not significantly different when compared to the control. For the optimum cheonggukjang processingconditions, 13 experimental points were selected. Soybean and EPM were chosen as independent variables. Viablecell count, pH, texture, and overall preference were measured. The optimum formulation of cheonggukjang usingthe numerical analysis was found to be 98.52% soybean and 1.48% EPM, resulting in a 0.722 desirability value.
        4,000원
        79.
        2014.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Multi-walled carbon nanotube reinforced epoxy composites were fabricated using shear mixing and sonication. The mechanical, viscoelastic, thermal, and electrical properties of the fabricated specimens were measured and evaluated. From the images and the results of the measurements of tensile strengths, the specimens having 0.6 wt% nanotube content showed better dispersion and higher strength than those of the other specimens. The Young's moduli of the specimens increased as the nanotube filler content was increased in the matrix. As the concentrations of nanotubes filler were increased in the composite specimens, their storage and loss moduli also tended to increase. The specimen having a nanotube filler content of 0.6 wt% showed higher thermal conductivity than that of the other specimens. On the other hand, in the measurement of thermal expansion, specimens having 0.4 and 0.6 wt% filler contents showed a lower value than that of the other specimens. The electrical conductivities also increased with increasing content of nanotube filler. Based on the measured and evaluated properties of the composites, it is believed that the simple and efficient fabrication process used in this study was sufficient to obtain improved properties in the specimens.
        4,000원
        80.
        2014.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Au 정광으로부터 Au Ag의 용출율을 향상시키기 위하여 기계적-화학적 활성화와 티오요소-티오시안산염 혼합용액을 적용하였다. 기계적-화학적 활성화를 이루기 위하여 정광 시료를 건식으로 그리고 습식으로 미분쇄하였다. 입도분포 분석과 XRD 분석 결과, 평균 입도 크기와 결정크기는 정광 시료보다 건식-시료에서 그리고 건식-시료보다 습식-시료에서 더 작게 나타났다. SEM과 XRD 분석 결과 기계적-화학적 활성화에 의해서 습식-시료에서 비정질화 현상이 관찰되었다. Au Ag에 대한 용출실험을 티오요소 용액, 티오시안산염 용액 그리고 티오요소-티오시안산염 혼합 용액으로 각각 수행하였다. Au Ag 용출율은 정광 시료보다 건식-시료에서 그리고 건식-시료보다 습식-시료에서 더 높게 나타났다. Au Ag는 티오요소 용액에서 보다 티오시안산염 용액에서 그리고 티오시안산염 용액에서보다 티오요소-티오시안산염 혼합 용액에서 더 높게 용출되었다. 습식-시료와 티오요소-티오시안산염 혼합 용액을 적용할 때 Au Ag가 99% 이상으로 용출되었다.
        4,200원
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