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        검색결과 118

        3.
        2024.01 KCI 등재 구독 인증기관 무료, 개인회원 유료
        A thorough knowledge and understanding of the structure–property relationship between thermal conductivity and C-fiber morphology is important to estimate the behavior of carbon fiber components, especially under thermal loading. In this paper, the thermal conductivities of different carbon fibers with varying tensile modulus were analyzed perpendicular and parallel to the fiber direction. Besides the measurement of carbon fiber reinforced polymers, we also measured the thermal conductivity of single carbon fibers directly. The measurements clearly proved that the thermal conductivity increased with the tensile modulus both in fiber and perpendicular direction. The increase is most pronounced in fiber direction. We ascribed the increase in tensile modules and thermal conductivity to increasing anisotropy resulting from the orientation of graphitic domains and microvoids.
        4,000원
        4.
        2024.01 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The discharge of industrial oily wastewater and oil spill accidents has resulted in significant environmental pollution, creating an urgent need for the treatment of oily wastewater. Nanofiber membranes, known for their high stability, flux, and efficiency, are widely employed in oil–water separation. This study systematically compared the performance of polyacrylonitrile/ graphene oxide (PAN/GO) composite nanofiber membranes prepared through immersion and electrospinning methods for oily wastewater treatment. Experimental findings demonstrated that immersion-prepared membranes achieved high flux (772.9 ± 2.9 L·m−2·h−1, n-hexane/water mixture) and efficiency (98.8%) at a GO concentration of 1.0 g/mL. On the other hand, electrospinning-prepared membranes exhibited superior flux (1500.3 ± 4.4 L·m−2·h−1, n-hexane/water mixture) and efficiency (99.6%) at a higher GO concentration (1.5 g/mL). This membrane displayed excellent stability, maintaining their exceptional performance even after ten cycles of separation. This study compared the advantages and disadvantages of the two methods for preparation of PAN/GO composite nanofiber membrane, offering valuable guidance for practical applications.
        4,600원
        5.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        ‘근본악’은 칸트가 규정하는 도덕법칙을 위협하는 ‘자연적 충 동성’이라는 악의 상태이다. 칸트는 인간이 어떤 도덕적 준칙을 자유롭게 채택할 때 선천적으로 악을 따르는 경향이 있다고 하 였다. 이는 『성경』에 나오는 아담의 원죄와 마찬가지로 ‘근본 악’도 인간의 자유에서 비롯된다는 즉, 선택의지의 자유를 따르 는 결과이다. 도덕법칙이 이성을 훈육하고 강화하는 원리로써 존중되어 왔다면 ‘근본악’은 경계해야 하는 것으로 간극되어 왔 다. 하지만 최근 현대 영상물에서는 악이라는 빌런이 주인공으 로 등장하면서 악에 담긴 의미의 재해석이 되고 있다. 따라서 본 연구는 칸트의 ‘근본악’개념을 바탕으로 중국 고전 속 대표 적인 악인 캐릭터 반금련이 현대 대중문화 속에서 감성과 이성 의 가치를 전도하면서 핫한 이슈로 존속되는 의미를 분석한 다. 또한 악에 대한 자유로운 선택의 단서는 바로 인간의 원초 적 욕망에 있다는 점에서 반금련 캐릭터는 도덕 법칙을 이탈시 키는 존재일 뿐만 아니라 사회에 문란한 질서를 재생산하는 상 징체계에 의문을 제기하는 존재로 해석하면서 그 해석을 논증 하는 것을 궁극 목적으로 삼는다.
        8,100원
        6.
        2023.11 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study investigated the surface tension and foaming properties of the hot-water extracts of pumpkin leaf and chickpea, as well as the effects of the plant hot-water extracts on white pan bread baking. Propylene glycol alginate (PGA), a synthetic emulsifier widely used in bakery, was used as a control. Pumpkin leaf water extract showed lower surface tension and comparable foaming capacity, compared with chickpea water extract and PGA solution when total solid  0.15% (w/w). Chickpea water extract showed the highest foam stability when total solid  0.15% (w/w). The dough was found to have a weak gel structure, and its viscoelastic properties were not significantly influenced by adding 0.05% or 0.15% (w/w) (based on total solid content) plant water extracts or PGA. The specific volume of the bread increased, and the baking loss was reduced by adding the two plant water extracts of total solid 0.15% (w/w). The hardness and chewiness of the bread crumb were reduced to a level comparable to the crumb containing 0.05% (w/w) PGA. The results showed that the pumpkin leaf water extract could be an effective natural emulsifier with a high phenolic content for bakery products.
        4,000원
        8.
        2023.05 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, we have fabricated the phenolic resin (PR)/polyacrylonitrile (PAN) blend-derived core-sheath nanostructured carbon nanofibers (CNFs) via one-pot solution electrospinning. The obtained core-sheath nanostructured carbon nanofibers were further treated by mixed salt activation process to develop the activated porous CNFs (CNF-A). Compared to pure PAN-based CNFs, the activated PR/PAN blend with PR 20% (CNF28-A)-derived core-sheath nanostructured CNFs showed enhanced specific capacitance of ~ 223 F g− 1 under a three-electrode configuration. Besides, the assembled symmetric CNF28-A//CNF28-A device possessed a specific capacitance of 76.7 F g− 1 at a current density of 1 A g− 1 and exhibited good stability of 111% after 5,000 galvanostatic charge/discharge (GCD) cycles, which verifies the outstanding long-term cycle stability of the device. Moreover, the fabricated supercapacitor device delivered an energy density of 8.63 Wh kg− 1 at a power density of 450 W kg− 1.
        4,500원
        12.
        2022.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Carbon fibers (CFs) are considered promising composite materials for various applications. However, the high cost of CFs (as much as $26 per kg) limits their practical use in the automobile and energy industries. In this study, we developed a continuous stabilization process for manufacturing low-cost CFs. We employed a textile-grade polyacrylonitrile (PAN) fiber as a low-cost precursor and UV irradiation technique to shorten the thermal stabilization time. We confirmed that UV irradiation on the textile-grade PAN fibers could lower the initial thermal stabilization temperature and also lead to a higher reaction. These resulted in a shorter overall stabilization time and enhancement of the tensile properties of textilegrade PAN-based CFs. Our study found that only 70 min of stabilization time with UV irradiation was required to prepare textile-grade PAN-based low-cost CFs with a tensile strength of 2.37 ± 0.22GPa and tensile modulus of 249 ± 5 GPa.
        4,000원
        13.
        2022.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study was performed to evaluate the effect of pork belly thickness on physicochemical and sensory characteristics after pan frying. Pork belly with three different thickness (5, 10, 20 mm) from three different parts (A:thoracic vertebrae no. 5-9, B:thoracic vertebrae 10-14, C:lumbar vertebrae 1-6) was pan grilled with electronic grill until it reached an internal temperature of 71℃. Cooking loss, shear force, sensory characteristics, volatile compounds of cooked pork belly were determined. Electric nose analysis was performed to support descriptive analysis and consumer sensory analysis. The cooking loss of pork belly with 20 mm thickness from all positions was significantly low (p<0.05). Shear force increased with increase in thickness (p<0.05). Electric nose identified major seven volatile compounds such as acetonitrile, (Z)-4-heptenal, 2-octanol, linalool, carbon disulfide, methylcyclohexane, n-nonanal to discriminate those samples. The part of pork belly significantly affected the intensity of volatile compounds rather than thickness. In discriminate analysis, the overall acceptability of pork belly (A and B parts) with 20 mm thickness was higher than that of pork belly with 5 mm thickness. In addition, the overall acceptability by consumers for pork belly with 20 mm thickness from A, B, and C parts was higher than the overall acceptability for pork belly with 5 mm thickness. This preliminary study suggests that it is more desirable to use pork belly with 20 mm thickness from part A when cooking on a pan gril compared with pork belly of 10 mm or 20 mm thickness from part B or C in the meat markets and restaurant.
        4,500원
        16.
        2021.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, nitric acid oxidation with varied treatment temperature and time was conducted on the surfaces of polyacrylonitrile- based ultrahigh modulus carbon fibers. Scanning electron microscopy, X-ray photoelectron spectroscopy, Raman spectroscopy and surface tension/dynamic contact angle instruments were used to investigate changes in surface topography and chemical functionality before and after surface treatment. Results showed that the nitric acid oxidation of ultrahigh modulus carbon fibers resulted in decreases in the values of the crystallite thickness Lc and graphitization degree. Meanwhile, increased treating temperature and time made the decreases more obviously. The surfaces of ultrahigh modulus carbon fibers became much more activity and functionality after surface oxidation, e.g., the total surface energy of oxidized samples at 80 °C for 1 h increased by 27.7% compared with untreated fibers. Effects of surface nitric acid oxidation on the mechanical properties of ultrahigh modulus carbon fibers and its reinforced epoxy composites were also researched. Significant decreases happened to the tensile modulus of fibers due to decreased Lc value after the nitric acid oxidation. However, surface treatment had little effect on the tensile strength even as the treating temperature and processing time increased. The highest interfacial shear strength of ultrahigh modulus carbon fibers/epoxy composites increased by 25.7% after the nitric acid oxidation. In the final, surface oxidative mechanism of ultrahigh modulus carbon fibers in the nitric acid oxidation was studied. Different trends of the tensile strength and tensile modulus of fibers in the nitric acid oxidation resulted from the typical skin–core structure.
        4,500원
        17.
        2021.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        반천수(潘天壽, Pan Tianshou, 1897-1971)는 20세기 중국 회화사를 대표하는 위대한 화가이자 중국화의 발전을 위하여 헌신해 온 교육가로서 오창석(吳昌碩1844-1927), 제백석(齊白石 1863-1957), 황빈홍(黃賓虹1864-1955)과 함께 중국 근현대화단의 4대가(四大家) 중 한 사람이다. 반천수가 활동했던 당시의 중국화단은 서양화의 유입으로 전통 문인화가 점차 쇠퇴해가던 시기였다. 이런 상황에서 반천수는 굳건히 전통을 지키면서도 그 속에서 중국화의 창신(創新) 을 이루고자 노력하였고 개성이 넘치고 독창적인 회화 형식을 창출함으로써 자신만의 예술세계를 표출해 내었다. 특히 그의 ‘화조 산수화’는 실경사생(實景寫生)을 통하여 터득한 창작 회화형식으로서 화조화와 산수화의 융합이자 전통 중국화의 회화범주를 과감히 깨뜨린 창신(創新)의 시도라 할 수 있다. 또한 그의 자연미에 대한 새로운 인식과 현대적 예술 정신이 깃들어 있다. 반천수의 ‘화조 산수화’ 작품의 특징은 첫째, 서예의 필법을 응용한 강기골의 운필로 필선이 강하고 기세가 넘치며 독창적인 구도를 가지고 있다. 둘째, 실경사생을 통한 일각식(一角式) 근경산수(近景山水)를 구현하여 현장감 넘치는 화면을 만들어 내었다. 셋째, 화면을 집중시키는 반공석(潘公石)을 과감하게 배치하여 화면을 경영하면서 조험(造险)과 파험(破脸)의 경계를 자유자재로 넘나들었다. 넷째, 화면의 네 면을 모두 에워싸는 사면 포위식(四面包圍式) 구도는 그림 속에 또 다른 여백의 공간을 만들어내어 그려진 경물들과 강한 대비를 이루며 허실 상생(虛實相生)의미를 보여주고 있다.
        6,700원
        19.
        2021.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Attempts to increase the usability of lilies led us to prepare pulverized lily bulbs, which we then added to bread flour to bake white pan bread. The properties of the frozen dough and the quality characteristics of the bread were analyzed. Our experiments showed that the addition of lily powder decreases the viscoelasticity and stability of frozen dough. The absorption rate of the frozen dough was 63.1±0.2% for the control sample, and 66.1±0.1% and 70.9±0.2% for the normally pulverized samples containing 3% and 5% of lily powder, respectively, whereas the absorption rate of the finely pulverized samples tended to increase slightly. The gelatinization results of the frozen dough decreased with the addition of lily powder in terms of the final viscosity, break down, and setback values. Compared to the control sample, the specific volume of the bread products that underwent normal pulverization (5% additive) increased slightly and decreased for the lily bulbs that were finely pulverized (3% additive). The addition of lily powder did not significantly affect the water activity during the storage period of up to 5 days. The hardness of white pan bread increased from 1,948±114.3 to 2,518±154.7 g/㎠ on the first day of storage to 2,571±160.9 to 3,265±147.4 g/㎠ on the 5th day of storage. The hardness was the highest for the 5% sample that underwent normal pulverization, and the samples differed significantly. The longer the storage period, the lower the springness value of the white pan bread became, and this result was most notable for the finely pulverized powder sample. The springness of white pan bread decreased as the amount of lily powder additive and the storage period increased. The sensory test results were excellent in that the appearance, texture, flavor, taste, and overall preference for white pan bread to which 3% of normally crushed lily powder had been added had improved relative to the control sample.
        4,000원
        20.
        2020.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study was conducted to evaluate the characteristics of bread and the rheology of flour dough containing chlorella powder(0%, 0.5%, 1.0%, 1.5%, 2.0% and 2.5%). In the farinograph test, the addition of chlorella powder changed water absorption, development time and mixing tolerance index for making bread. As the amount of chlorella powder increased, the water absorption increased, mixing tolerance index and the development time decreased. In the extensograph test, the degree of extension and resistance was decreased with increasing of chlorella powder content. In the amylograph test, the maximum viscosity was slightly decreased with increasing of chlorella powder contents. The colors of L value in bread crumb was significantly decreased as the chlorella powder addition. After fermentation treatment, The dough with 2.5% chlorella powder showed the lowest dough raising power compared to the other doughs. The addition of the chlorella powder had significant effect on bread texture. The bread consisting of 0.5% chlorella powder showed the highest volume of loaf and specific volume. Therefore, high quality of bread can be achieved by adding chlorella powder.
        4,200원
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