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        검색결과 547

        181.
        2016.10 구독 인증기관·개인회원 무료
        Protein and polysaccharide are used as many food function including emulsifying and stabilizing agent. Some food emulsions are in low pH such as sorbet ice cream, soft drink, salad dressing etc. According to our previous study was found that fish gelatin (FG) and sodium alginate (AL) mixture provide the information to be a new food emulsifier including at low pH condition (pH 3.5). In addition the study of interfacial rheology has been interested to interpret the formation and stabilization of food emulsion. Then the objective of this study was to investigate the relationship between emulsifying characteristics and interfacial shear rheology of acidified emulsion which was stabilized by FG and AL mixture, compared with a commercial gum arabic (GA). The mixtures of FG and AL were separately prepared with phosphate-citrate buffer at pH 3.5 and 1 %w/v of total concentration. The ratio of FG:AL was 100:0, 80:20, 50:50, 80:20, and 0:100 by weight. They were mixed at 24±2 oC for 90 minutes and kept at the same temperature for 24 hours to reach equilibrium. The emulsion was prepared by adding 1.5 g of olive oil in 100 ml of mixture and homogenized by high speed homogenizer at 10,000 rpm for 10 min at 24±2 oC. The emulsion stabilized with 20:80 showed the best stability after 14 days. The result could be supported by low interfacial tension, high bulk viscosity, and electrostatic repulsion (minus value of electrophoretic mobility). For interfacial shear rheology (storage modulus, G' and loss modulus, G''), G' of 20:80 seem wider liner viscoelastic region which mean more resistance to fracture at interface. While the magnitude of G' and different value of G' and G'' were not difference. In addition, the interfacial shear viscosity of 20:80 also showed high resistance to flow at low shear rate (0.001 - 0.1 s-1). Keywords: Fish gelatin, Sodium alginate, Emulsion, Interfacial shear rheology
        182.
        2016.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 초음파 진동에 의해 발생하는 공동현상을 이용하여 다양한 유용성분과 생리활성을 가지고 있는 녹차와 애엽을 혼합하여 새로운 식품소재를 개발하기 위해서 반응표면분석법에 의한 추출특성을 모니터링 하여 최적 추출조건을 예측하였다. 초음파를 지속적으로 가하는 조건에서 Box-Behnken design에 의해 녹차와 애엽의 혼합비, 용매와 용질의 비, 추출시간을 독립변수로 하여 15구간의 추출조건을 설정하고 추출수율(Y)을 종속변수로 하여 모니터링 하였다. 반응표면분석결과 녹차 및 애엽 혼합 추출물은 녹차의 함량과 추출용매의 양이 증가 할수록 추출 수율이 증가 하였으며, 추출시간은 결과에 큰 영향을 주지 않는 것으로 나타났다. 추출수율을 최대로 얻을 수 있는 녹차 및 애엽 혼합물의 최적 추출조건은 녹차와 애엽의 혼합비 85.86%, 용매와 용질의 비 92.73 mL/g, 추출시간 56.52분으로 확인되었으며, 추출수율의 최대값은 30.03% 로 예측되었다.
        4,000원
        183.
        2016.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        A sintered body of TiB2-reinforced iron matrix composite (Fe-TiB2) is fabricated by pressureless-sintering of a mixture of titanium hydride (TiH2) and iron boride (FeB) powders. The powder mixture is prepared in a planetary ball-mill at 700 rpm for 3 h and then pressurelessly sintered at 1300, 1350 and 1400oC for 0-2 h. The optimal sintering temperature for high densities (above 95% relative density) is between 1350 and 1400oC, where the holding time can be varied from 0.25 to 2 h. A maximum relative density of 96.0% is obtained from the (FeB+TiH2) powder compacts sintered at 1400oC for 2 h. Sintered compacts have two main phases of Fe and TiB2 along with traces of TiB, which seems to be formed through the reaction of TiB2 formed at lower temperatures during the heating stage with the excess Ti that is intentionally added to complete the reaction for TiB2 formation. Nearly fully densified sintered compacts show a homogeneous microstructure composed of fine TiB2 particulates with submicron sizes and an Fe-matrix. A maximum hardness of 71.2 HRC is obtained from the specimen sintered at 1400oC for 0.5 h, which is nearly equivalent to the HRC of conventional WC-Co hardmetals containing 20 wt% Co.
        4,000원
        185.
        2016.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study amied to determine the effect of species and seed mixture on productivity, botanical composition and forage quality in middle mountainous region (Geosan) pasture. Total seven experimental pastures (T1 : Orchardgrass, T2 : Timothy, T3 : Tall fescue, T4 : Perennial ryegrass, T5 : Kentucky bluegrass, T6 : Timothy + Orchardgrass + Tall fescue + Alfalfa, T7 : Timothy + Orchardgrass + Kentucky bluegrass + White clover) were established in autumn, 2014 and evaluated for productivity and agronomic characteristics for 2015. Plant heigh was high in Orchardgrass and Perennial ryegrass pasture. Dry matter (DM) content was high in Kentucky bluegrass. Botanical composition in 1st harvest was high in shrub, but the grass composition was high in 2nd and 3rd harvest. Fresh and DM yield were higher in Orchardgrass and Perennial ryegrass (p<0.05); whreras, Kentucky bluegrass was the lowest. In seed mixture pasture, yields of T6 plot (Tall fescue) were higher than those of T7 (Kentucky bluegrass). Average CP (crude protein) content of 2nd and 3rd cutting time was 16.91 and 14.79%, respectively and Kentucky blue grass was the highest in 3rd cutting time by 17.57%. IVDMD (in vitro dry matter digestibility) showed low in 1st cutting and Kentucky bluegrass was the lowest in every cutting time. TDN (total digestible nutrient) content was the highest in 3rd cutting and the lowest in 1st cutting. These results indicated that Orchardgrass, Perennial ryegrass and T6 are recommendable for productivity and Timothy, Perennial ryegrass and T7 are recommendable for forage quality.
        4,000원
        186.
        2016.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        PURPOSES: This study aims to show the difference of the binder aging level in the hot-mix asphalt (HMA) mixture after short-term aging (SA) under different aging conditions, such as mixture temperature and duration in hour. METHODS: Three SA times (i.e., 1 h, 2 h, and 4 h) at two temperatures (i.e., 160℃ and 180℃) were used for the normal mixtures prepared using a PG64-22 asphalt. The field long-term aging (LA) was simulated by applying the same LA procedure (65 h at 110℃) to all compacted specimens, prepared at the air void of 7% using each SA-treated mixture, in a convection oven. The binder aging level was measured in terms of large molecular size by gel-permeation chromatography (GPC) from the mixture and the absolute viscosity (AV) from the recovered binder. The aging levels were evaluated using those two properties after SA and LA, and then compared based on the normal SA (NSA) mixture (1 h at 160℃). The service life reduction caused by SA in various conditions was estimated based on the aging level of the field cores from different locations in various service lives. RESULTS: The results of the laboratory evaluation indicated that the binder of the mixture, which was treated at longer SA time and higher temperature, showed a significantly higher aging level than the NSA mixture. The binder aging level from a longer time, such as 2 h and 4 h SA, or at a higher temperature (180℃), were estimated to be similar to that of the mixtures, which had already been in field service for several years. CONCLUSIONS : The HMA mixture should be produced at a moderate temperature, such as 160℃, and placed within a limited hauling and queuing time to avoid a significant short-term aging of the binder before placement in the field pavement. The SA for a longer time at a higher temperature than the NSA condition was found to be detrimental to the service life of the asphalt pavement.
        4,000원
        187.
        2016.05 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Sea cucumber (SC) or Stichopus japonicas is widely used in East Asia as a traditional medical component for the treatment of asthma, arthritis, and sinus congestion. The hydrolysate of SC (HSC) after treatment with a protease is also widely used as an ingredient for processed food application such as noodles. Tensile force and deformation are important texture properties of noodle. The peptides prepared by hydrolyzing SC could affect the tensile properties of noodle, as well as DPPH radical scavenging. The objectives of this study were to characterize the tensile properties, the texture properties, color, and DPPH radical scavenging of noodle with HSC and to determine an optimum formulation of dough with HSC for noodle. The HSC was prepared by hydrolyzing dried SC powder with distilled water (DW) and a protease, Protamex (Novozyme Nordisk, Bagsvaerd, Danmark). The tensile properties and antioxidant activity were used as major constraint functions for the optimization. The optimum ratio was determined as flour:water:HSC=69.27:22.48:7.05 (w/w). Increasing the amount of HSC in the formulation increased the tensile force but no significant difference was observed in the deformation.
        4,000원
        188.
        2016.05 구독 인증기관·개인회원 무료
        분리막을 이용한 투과증발법은 에너지 소모가 적고 경제적이며 환경친화적이기 때문에 분자스케일 액체/액체 분리에 있어서 매우 주목 받고 있는 기술이다. 방향족 화합물과 지방족 화합물을 분리하는 공정은 석유정제, 석유화학공정 등 에서 특히 중요한 분리공정 중의 하나이다. 본 연구에서는 벤젠에 대한 고선택 성을 나타내는 PEG가 함유된 폴리이미드 공중합체를 합성하였고, 1H-NMR 스 펙트럼과 FT-IR 스펙트럼에서 PEG 특성 피크의 확인을 통하여 PEG가 도입되었 음을 확인 하였다. 혼합물 분리를 위한 투과증발 실험 장치를 제작하여 PEG 함량이 다른 막을 제조하여 벤젠 조성 변화에 따른 투과증발 실험을 실시하였 으며, 그에 따른 투과유량 및 투과도를 계산하여 투과특성을 확인하였다.
        189.
        2016.05 구독 인증기관·개인회원 무료
        최근 물 부족 문제가 대두되면서 막기반 해수담수화 기술이 해결책으로 주목 받고 있다. 공정 기술에서 에너지 소모 저감이 핵심으로 고려되고 있는 가운데, 고분자 막기반 해수담수화 공정의 에너지 소모량이 더 이상 줄어들지 않는 정체 현상을 보이면서, 성능 향상 및 에너지 소모량을 줄이기 위한 막개발이 핵심 으로 고려되고 있다. 최근 신소재를 이용한 막개발이 활발한 가운데, 원자수준 의 두께 및 물리/화학적 안정성, 높은 강도 등을 장점으로 하는 그래핀 (Graphene) 막 개발 연구가 진행되고 있다. 본 연구에서는 물질이동 기작을 밝히기 위해 물 및 유기 용매가 그래핀 막에서 가지는 투과 성능을 온도 및 습도 조건을 달리하는 조건에서 측정하고, 이를 바탕으로 그래핀 막의 투과 성능 및 기작에 대해 평가하고자 하였다.
        190.
        2016.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study was designed to develop and to qualify a coffee alternative beverage using a mixture of coffee beans and roasted black beans (Rhynchosia nulubilis). Therefore, the total isoflavone content (TIC), total phenol content (TPC), antioxidant activity, anti-inflammatory activity, NFATc1 (Nuclear factor of activated T-cells c1) expression in RANKL (receptor activator of nuclear factor kappa-B ligand)-stimulated RAW264.7 cells and sensory evaluation were measured for 5 different Cb (coffee bean)-RoS (roasted seomoktae) mixture extracts (Cb100RoS0, Cb75RoS25, Cb50RoS50, Cb25RoS75, and Cb0RoS100). Cb0RoS100 had the highest TIC (516.83±36.61 mg/100 g) and TPC (18.11±1.77 mg TAE/100 g) along with the highest antioxidant activity as measured by DPPH radical scavenging activity (73.55±8.11%) and ABTS radical scavenging activity (63.27±7.27%). Also, Cb0RoS100 showed the highest anti-inflammatory activity as measured by NO production (13.57±2.21 μM) and PGE2 production (3.25±0.21 ng/mL). The more the RoS ratio was increased in the mixtures of Cb-RoS, the more the NFATc1 protein expression was decreased in RANKL-stimulated RAW264.7 cells. In case of sensory evaluation, Cb50RoS50 had the highest scores for flavor, delicate flavor and overall quality, which were similar to those in Cb alone (Cb100RoS0). We suggest that the use of RoS replacement instead of Cb in/as a coffee alternative beverage may help to reduce the risk of caffeine-related bone loss and/or bone disease by effectively blocking NFATc1 expression in RANKLstimulated RAW264.7 cells compared with Cb alone.
        4,000원
        191.
        2016.03 KCI 등재후보 구독 인증기관 무료, 개인회원 유료
        Vitis amurensis, Aralia cordata, and Glycyrrhizae radix have been widely used as oriental medicinal plants in Korea, China and Japan and found to possess anti-oxidative and anti-inflammatory activities. A previous study demonstrated a protection of an ethanol extract (SSB) of a mixture of three medicinal plants of Vitis amurensis, Aralia cordata, and Glycyrrhizae radix against β amyloid protein-induced memory impairment. The current study was conducted to investigate the neuroprotective effect of SSB against ischemiainduced brain injury. Transient focal cerebral ischemia was induced by 2 hr middle cerebral artery occlusion followed by 24 hr reperfusion (MCAO/reperfusion) in rats. Oral administration of SSB (5, 10 and 25 mg/kg) 30 min before and 1 h after MCAO, and 1 h after reperfusion reduced MCAO/ reperfusion-induced brain infarct and edema formation. SSB also inhibited development of behavioral disabilities in MCAO/reperfusion-treated rats. Exposure of cultured cortical neurons to 500 μM glutamate for 12 hr resulted in neuronal cell death. SSB (1-10 μg/mL) inhibited glutamateinduced neuronal death, elevation of intracellular calcium concentration ([Ca2+]i), and generation of reactive oxygen species (ROS). These results suggest that the neuroprotective effect of SSB against ischemia-induced brain damage might be associated with its anti-excitotoxic activity and that SSB may have a therapeutic role for prevention of neurodegeneration in stroke.
        4,000원
        192.
        2016.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        PURPOSES : This study primarily focused on evaluating the performance characteristics of 4.75-mm nominal maximum aggregate size (NMAS) asphalt mixtures for their more effective implementation to a layered flexible pavement system. METHODS: The full-scale pavements in the FDOT’s accelerated pavement testing (APT) program, including 4.75-mm mixtures at the top with different thicknesses and asphalt binder types, were considered for the faster and more realistic evaluation of the rutting performance. The results of superpave indirect tensile (IDT) tests and hot-mix asphalt fracture mechanics (HMA-FM) based model predictions were used for cracking performance assessments. RESULTS: The results indicated that the rutting performance of pavement structures with 4.75-mm mixtures may not be as good as to those with the typical 12.5-mm mixtures, and pavement rutting was primarily confined to the top layer of 4.75-mm mixtures. This was likely due to the relatively higher mixture instability and lower shear resistance compared to 12.5-mm mixtures. The energy ratio (ER) and HMA-FM based model performance prediction results showed a potential benefit of 4.75-mm mixtures in enhanced cracking resistance. CONCLUSIONS : In relation to their implementation, the best use of 4.75-mm mixtures seem to be as a surface course for low-trafficvolume applications. These mixtures can also be properly used as a preservation treatment that does not necessarily last as long as 12.5-mm NMAS structural mixes. It is recommended that adequate thicknesses and binder types be considered for the proper application of a 4.75-mm mixture in asphalt pavements to effectively resist both rutting and cracking.
        4,000원
        194.
        2015.11 구독 인증기관·개인회원 무료
        This study was carried out to investigate optimal mixture of persimmon peels for Pleurotus eryngii cultivation. The 5-50% of persimmon peels was mixed with mushroom growing medium for Pleurotus eryngii cultivation. Mycelial growth of persimmon peels treatment were 74-165 mm (28 days) and slower than that of control (treatment without persimmon peels) as 160 mm (28 days). Mycelial growth time of 5-20% persimmon peels treatment were similar to control as 34 days but that 30-50% of persimmon peels treatment were delayed for 17 days. The time of pinhead formations in control and 5-50% persimmon peels treatment were 11 days, the growth time to harvest were 6-7 days. The sizes of pileus of 15% persimmon peels treatment was tend to be smaller compared with control. The length of stipe of 15% persimmon peels treatment was 124 mm which was longer than that of the control with 118 mm. The thickness of stipes of 15% persimmon peels treatments was 48 mm which were tend to be thicker than that of the control with 47 mm. Thirty percent of persimmon peels treatment was better than other treatment comparing with control.
        195.
        2015.11 구독 인증기관·개인회원 무료
        분리막을 이용한 투과증발법은 에너지 소모가 적고 경제적이며 환경친화적이기 때문에 분자스케일 액체/액체 분리에 있어서 매우 주목 받고 있는 기술이다. 방향족 화합물과 지방족 화합물을 분리하는 공정은 석유정제, 석유화학공정 등에서 특히 중요한 분리공정 중의 하나이다. 본 연구에서는 벤젠에 대한 고선택성을 나타내는 PEG가 함유된 폴리이미드 공중합체를 합성하였고, 1H-NMR 스펙트럼과 FT-IR 스펙트럼에서 PEG 특성 피크의 확인을 통하여 PEG가 도입되었음을 확인 하였다. 혼합물 분리를 위한 투과증발 실험 장치를 제작하여 PEG 함량이 다른 막을 제조하여 벤젠 조성 변화에 따른 투과증발 실험을 실시하였으며, 그에 따른 투과유량 및 투과도를 계산하여 투과특성을 확인하였다.
        196.
        2015.11 구독 인증기관·개인회원 무료
        연료로부터 벤젠 또는 톨루엔과 같은 유독한 방향족 성분의 제거 및 분리는 최대 허용 농도의 감소로 인해 점점 더 많이 주목 받고 있다. 그 중에서도 가솔린의 벤젠 함량은 지금 법률상으로 유럽에서 1% 이하로 제한되고 있다. 이러한 분리공정에 있어서 에너지의 소모를 줄이고 분리효율을 높일 수 있는 투과증발 공정이 각광을 받고 있다. 본 연구에서는 벤젠에 대한 고선택성을 나타내는 sulfonated SEBS 공중합체를 합성하였고, 1H-NMR과 FT-IR 분석을 통해 술폰화가 되었음을 확인 하였다. 혼합물 분리를 위한 투과증발 실험 장치를 제작하여 sulfonated SEBS막을 제조하여 벤젠 조성 변화에 따른 투과증발 실험을 실시하였으며, 그에 따른 투과유량 및 투과도를 계산하여 투과특성을 확인하였다.
        199.
        2015.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Fe-30 wt% TiC composite powders are fabricated by in situ reaction synthesis after planetary ball millingof (Fe, TiH2, Carbon) powder mixture. Two sintering methods of a pressureless sintering and a spark-plasma sinteringare tested to densify the Fe-30 wt% TiC composite powder compacts. Pressureless sintering is performed at 1100, 1200and 1300oC for 1-3 hours in a tube furnace under flowing argon gas atmosphere. Spark-plasma sintering is carried outunder the following condition: sintering temperature of 1050oC, soaking time of 10 min, sintering pressure of 50 MPa,heating rate of 50oC/min, and in a vacuum of 0.1 Pa. The curves of shrinkage and its derivative (shrinkage rate) areobtained from the data stored automatically during sintering process. The densification behaviors are investigated fromthe observation of fracture surface and cross-section of the sintered compacts. The pressureless-sintered powder com-pacts are not densified even after sintering at 1300oC for 3 h, which shows a relative denstiy of 66.9%. Spark-plasmasintering at 1050oC for 10 min exhibits nearly full densification of 99.6% relative density under the sintering pressure of50 MPa.
        4,000원
        200.
        2015.10 구독 인증기관·개인회원 무료
        Analyzing asphalt mixture images can provide crucial information not only for generating advanced geometry structure in several numerical computations (i.e. FEM and/or DEM) codes, but also for numerically evaluating the material microstructure. It is well known that 3D X-Ray Computer Tomography (CT) can provide accurate and realistic microstructure information of asphalt mixtures; however, this technology still presents two limitations: 1) the equipment is very expensive and, therefore, only few pavement agencies can afford it, and 2) the software required to generate realistic image of asphalt mixture with three-phase structure (aggregate, asphalt binder and air-voids) is based on a global thresholding algorithm which cannot be easily accessed and edited by users and practitioners. In this paper, accurate and realistic 2D three-phase asphalt mixture images were generated using an advanced DIP analysis code (implemented on MATLABTM) and a common flatbed scanner, which can be easily purchased at relatively low price. The threshold algorithm was developed based on the computed results of Gmm (maximum specific gravity), Gmb (bulk specific gravity), VMA (voids in mineral aggregates) of given asphalt mixtures which can be experimentally obtained in a laboratory environment. 2D three-phase images of asphalt mixtures were derived from grey scale images (color intensity from 0 to 255) obtained from original RGB (Red-Green-Blue) scale images with a dual-threshold computation techniques (i.e. one step for computing air voids phase, T1, and a second step for computing asphalt binder (and/or mastic) phase, T2). An example of DIP analysis results is shown in Figure 1. Based on the computation results, quite accurate and good visual agreement was observed between RGB scale image and DIP analyzed image. The findings indicate that this advanced DIP analysis technique can provide reliable geometry and microstructural information for several numerical simulations such as finite element method (FEM) and discrete element modeling (DEM). This research work represents a solid base for performing simple 2D microstructure analysis using 2- and 3-point correlation function and for developing the Moon Cannone Falchetto (MCF) model which will be introduced in the next annual KSRE conference.