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        검색결과 1,536

        301.
        2018.05 구독 인증기관·개인회원 무료
        촉진수송막이란 특정기체의 이동을 촉진시키기 위한 운반체를 포함하고 있는 분리막을 말하며 일반적으로 올레핀/파라핀 분리에는 π-complexation을 할 수 있는 은이온이 운반체로 사용된다. 본 연구에서는 올레핀/파라핀 분리를 위해 은이온이 함침된 아민계 고분자를 이용하여 촉진수송막을 제조하였고 이들의 프로필렌/프로판 분리특성을 알아보았다. 순수가스 테스트를 통해 압력변화에 따른 투과도와 선택도를 구하였으며, 혼합가스 테스트를 통해 stage-cut에 따른 투과측 프로필렌 농도 및 회수율 변화를 알아보았다. 그 결과, 2bar, 25°C에서 95%의 프로필렌을 99.6%까지 농축 시킬 수 있음을 확인하였다.
        302.
        2018.05 구독 인증기관·개인회원 무료
        본 실험에서는 폴리올레핀을 이용하여 중공사 형태의 분리막을 제조하였다. 권취속도를 달리하여 중공사막을 제조하였으며, 보어로는 질소를 사용하였다. 제조된 중공사는 만능재료시험기를 이용하여 응력과 변현율을 측정하였다. 그리고 시차주사열량계(DSC)를 이용하여 각각의 샘플의 결정화도를 측정하였고, 권취속도와 어닐링 효과에 따른 결정화도의 거동을 조사하였다. 냉연신과 열연신을 거친 중공사 분리막은 전계방출형주사현미경(FE-SEM)을 이용하여 단면, 표면의 모폴로지를 관찰하였다.
        303.
        2018.05 구독 인증기관·개인회원 무료
        제련 산업 공정에서 방출되는 폐산 용액에는 다양한 유가 및 희소 금속을 함유하고 있으며 나노 분리막을 적용하여 폐산에 잔존하는 금속들을 경제적으로 분리, 회수하고자 한다. 본 연구에서는 15 wt% 폐산 용액에 적용 가능한 나노분리막을 제조하고자 하였으며, 다공성 PSf 지지막 위에 수용액상으로 다양한 aliphatic amine과 유기상으로 trimesoyl chloride (TMC), diisocyanate계를 계면중합하여 제조하였다. 분리막의 투과 평가는 75 psi 압력 하에서 cross-flow 방식으로 진행하였으며 내산성 평가는 15 wt% 황산 용액에 일별 노출한 후 투과 평가를 진행하였다. 제조막의 특성은 FTIR, XPS, FE-SEM 분석을 통해 확인하였다.
        304.
        2018.05 구독 인증기관·개인회원 무료
        본 연구에서는 roll to roll (R2R) 설비를 이용해 폭 60 cm의 역전기투석용 양이온 및 음이온교환막을 제막했다. 양이온 및 음이온교환막의 전해질로 아크릴아마이드계 술폰산 및 암모늄염, 가교제로 다이아크릴아마이드를 사용했다. 또한, 지지체로 16 um 두께의 PE계 다공성 필름을 사용했다. R2R 설비로 제작된 양이온 및 음이온교환막은 swelling 후 18 um의 두께, 0.6 Ω⋅cm² 이하의 저항, 85% 이상의 permselectivity, 1.3 meq g-1 이상의 ion exchange capacity(IEC)를 지니고 있었다. 또한, 제조된 이온교환막의 전극 유효면적 5 × 5 cm의 역전기투석 셀 test 결과 2.5 W/m²의 전력밀도를 보였다.
        305.
        2018.05 구독 인증기관·개인회원 무료
        현재 해수담수화 공정은 지속적인 연구를 통해 많은 개발이 이루어지고 있다. 그중 전기흡착탈이온(EAD) 공정은 이온교환막을 이용한 전기투석법과 이온교환수지를 이용한 이온교환수지법을 혼합하여 이루어지는 공정이다. 보다 효율적으로 이온교환이 이루어질 수 있는 공정이지만, 이온교환막 사이에 이온교환수지가 들어가기 때문에 사이즈가 비교적 크다. 또한, 이온교환수지의 크기 분포와 당량비가 모듈의 성능에 영향을 준다. 본 연구는 현재 상용화되고 있는 이온교환공정에서 쓰이고 있는 모듈의 문제해결과 성능 향상을 위해 보다 이온교환용량이 향상된 고분자와 현재 쓰이고 있는 일반적인 이온교환수지가 아닌 더 작고 균질한 이온교환능력을 가진 이온교환 나노입자를 제조하여 제막을 진행하였고, 다양한 특성평가가 이루어졌다.
        306.
        2018.05 구독 인증기관·개인회원 무료
        최근 많은 시간을 실내에서 생활하는 현대인에게 실내 공기의 질은 매우 중요한 개념으로 자리 잡고 있으며, 이는 현재 새롭게 대두되어야 할 문제이다. 실내 공기질은 온도, 습도 등으로 결정이 된다. 따라서 현재 이러한 인자를 제어하여 실내 공기질을 개선하고 있지만, 실내 공기질 개선을 위해서는 에너지소비가 심하다는 단점이 있다. 그리하여 전열 교환을 적용한 문제를 해결하려는 방법에 대한 연구가 활발히 이루어지고 있고, 전열 교환막을 이용하여 효과적으로 제어하고자 하는 많은 연구가 이루어지고 있는 추세이다. 따라서, 본 연구에서는 전열 교환 분리막 적용을 위하여, poly(styrene-ethylene-butylene-styrene)고분자에 암모늄을 도입하여 친수성을 가지는 아민화된 SEBS 고분자를 합성 및 특성평가를 진행하였다.
        307.
        2018.05 구독 인증기관·개인회원 무료
        제타전위를 이용한 분리막의 막오염 개선연구와 분리막의 표면전하 분석을 통한 고분자의 개질 확인 및 치환기 확인에 대한 연구는 활발히 진행되고 있다. 제타전위(zeta potential)란 전기역학적 현상으로 발생하는 전위차를 정량화 한값을 측정하는 것을 말한다. 이러한 제타전위를 측정하기 위해서는 전기영동(electrophoresis), 전기삼투(eletrosmosis), 유동전위(streaming potential)를 측정하는 예가 있고 그중 평막은 유동전위 측정이 적합하다. 따라서, 본 연구에서는 SEBS(polystyrene-ethylene-butylene-styrene) 고분자를 개질하여 아민화된 SEBS 평막형택의 분리막을 제조하고, 제조한 아민화된 SEBS 고분자 분리막을 계면동전위 측정기 이용으로 유동전위를 측정하여 결과를 분석하였다.
        308.
        2018.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The objective of this study was to investigate taste profiles and the correlation of Doenjang soup solution prepared with three different temperatures (5, 25, 45℃) and using an electronic nose (e-nose), electronic tongue (e-tongue), and descriptive analyses by trained panelists. A total of 17sensory attributes were generated from the descriptive analyses for the Doenjang soup solution. There were significant difference among the samples in the cooked soybean flavor, the cooked soybean odor, the soy sauce odor, the sweet odor, the sweet taste, and the sweet aftertaste attributes. The intensities of these sensory attributes tended to increase as the serving temperature of the Doenjang soup solution increased. There were seven volatile compounds detected by the electronic nose: ethanol, propanal, 2-methylpropanal, ethyl acetate, 3-methylbutanal, and beta-pinene. The intensities of the volatile compounds increased as the temperature of the Doenjang soup solution increased. On the other hand, the intensities of the basic tastes by the e-tongue decreased as the temperature of the Doenjang soup solution increased. In conclusion, the e-nose, e-tongue, and descriptive analysis results showed different correlations depending on the temperature of the Doenjang soup solutions.
        4,000원
        309.
        2018.04 구독 인증기관·개인회원 무료
        시범사업에서 생산된 쌀을 이용하여 간편식 제품 개발을 위한 기초자료를 확보하고자 고품질 밥쌀용 벼 7품종의 영양성분 및 취반특성 분석을 수행하였다. 수분함량은 진수미가 13.13%, 단백질 함량은 하이아미 품종이 6.08%, 지방은 하이아미 품종이 0.51%로 가장 높은 것으로 나타났다. 아밀로스 함량의 경우 20.15~22.51% 범위로 나타났으며, 수광이 가장 높은 것으로 확인되었다. 아밀로펙틴중합도 분석 결과 7종의 품종 모두 DP 13-24 함량이 53% 이상으로 가장 높았고, DP≥37 함량은 5.81% 이하로 가장 낮았다. 유리당 조성 분석 결과 7개의 품종 모두 maltose 함량이 46% 이상으로 높았으며, fructose 함량이 7% 이하로 가장 낮았다. 품종별 쌀 원료곡의 토요 윤기치를 측정한 결과 삼광, 대보, 진수미가 가장 높은 값을 나타내었고 취반식미 특성을 분석한 결과 대보, 진수미가 외관, 점도, 밸런스, 식미치 값이 높은 것으로 나타났다. 본 연구결과는 취반 및 재조리에 따른 밥의 품질특성 연구에 기초자료가 될 것으로 판단된다.
        310.
        2018.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        PURPOSES: The purpose of this research is to analyze the characteristics of panels that affect the evaluating results of riding quality and to evaluate the appropriateness of roughness management criteria based on ride comfort satisfaction. METHODS: In order to analyze the influence of panel characteristics of riding quality, 33 panels, consisting of civilians and experts, were selected. Also, considering the roughness distribution of the expressway, 35 sections with MRI ranging from 1.17 m/km to 4.65 m/km were selected. Each panel boarded a passenger car and evaluated the riding quality with grades from 0 to 10, and assessed whether it was satisfied or not. After removing outlier results using a box plot technique, 964 results were analyzed. An ANOVA was conducted to evaluate the effects of panel expertise, age, driving experience, vehicle ownership, and gender on the evaluation results. In addition, by using the receiver operating characteristics (ROC) curve, the MRI value, which can most accurately evaluate the satisfaction with riding quality, was derived. Then, the compatibility of MRI was evaluated using AUC as a criterion to assess whether the riding quality was satisfactory. RESULTS: Only the age of the panel participants were found to have an effect on the riding quality satisfaction. It was found that satisfaction with riding quality and MRI are strongly correlated. The satisfaction rate of roughness management criteria on new (MRI 1.6 m/km) and maintenance (MRI 3.0 m/km) expressways were 95% and 53%, respectively. As a result of evaluating the roughness management criteria by using the ROC curve, it was found that the accuracy of satisfaction was the highest at MRI 3.1-3.2 m/km. In addition, the AUC of the MRI was about 0.8, indicating that the MRI was an appropriate index for evaluating the riding quality satisfaction. CONCLUSIONS: Based on the results, the distribution of the panels’age should be considered when panel rating is conducted. From the results of the ROC curve, MRI of 3.0 m/km, which is a criterion of roughness management on maintenance expressways, is considered as appropriate.
        4,000원
        311.
        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
        312.
        2018.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        There has been growing concern over the emissions of formaldehyde and VOCs from automotive interior materials, as these could have an important impact on the in-vehicle air quality (IVAQ) of automotive vehicles. Odor, the components of which may include VOCs, refers to the automotive interior smell emitted directly or indirectly from any part of an automotive interior, based on human olfactory senses and a comfort evaluation of vehicle quality. The objective of this paper is to compare the instrument analysis with the sensory characteristics of an odor using GC/MS/Olfactometry. From the test, it was possible to identify the cause of odor, which can be difficult to distinguish among multiple odors, through the simultaneous performance of instrumental analysis and sensory evaluation.
        4,000원
        313.
        2018.02 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        In this study, ZrO2 ceramic ink was formulated for additive manufacturing three dimensional structure using dispenser printing technique. Ceramic ink with various ZrO2 loading (30, 40, 50vol%) was prepared to evaluate their rheological properties and printability. High ZrO2 loading ZrO2 ceramic ink showed higher elastic modulus and improved shape retention, when the ceramic ink was printed and sintered at 1450 oC for 1h. Microstructural analysis of printed ZrO2 objective indicated that high ZrO2 loading objective showed lower porosity and smaller pore size.
        4,000원
        314.
        2018.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구에서는 sol-gel법을 이용하여 균일하고 결함을 최소화한 세라믹 한외여과막을 제조하였다. 알루미나 중공 사 정밀여과막 지지체의 기공 크기를 줄이기 위해, 합성된 boehmite sol과 sol-ethanol 혼합 용액을 사용하여 dip coating법으 로 지지체 표면 위에 γ-알루미나 활성층을 형성시켰다. pristine sol을 이용하여 4회 이상 코팅했을 경우 박막층의 두께가 상당히 증가하여 균열 및 박리현상을 야기시키고, 3회 코팅을 진행하였을 경우 표면 결함이 최소화된 최적의 시료를 얻을 수 있었다. 또한, 소결 온도가 γ-알루미나 활성층의 기공 크기에 미치는 영향을 분석하였다. 소결 온도가 1000°C일 때 가장 높 은 순수 투과도 값을 보였으며, 10 nm 크기의 dextran 분획분자량(molecular weight cut-off (MWCO) : 51 kDa)이 관찰되었다. 600, 800°C에서 소결한 막의 경우, 12 kDa MWCO (dextran 5 nm)를 갖는 것으로 확인되었다. 결과적으로, 코팅 용액의 조성은 박막층의 두께에 큰 영향을 주었고, 소결 온도에 따라 분획분자량이 크게 영향을 받는 것을 알 수 있었다.
        4,000원
        315.
        2018.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, the whole process of 6xxx series aluminum cast alloy for high speed train interior or exterior parts are characterized. For casting, selection of optimum alloying elements, dissolution technology, de-gassing process, production of molds conforming to the conditions of use, development of casting process control technology for various shapes and materials are performed for the development of high-quality, high strength aluminum alloys. The development of more reliable lightweight aluminum and aluminum alloy for interior or exterior materials has been the scope of this study. The mechanical properties, and chemical composition of the case materials were evaluated for the 6063, 6061 and 6N01 alloy profiles and compared to the commercial materials and the evaluation results satisfied the standard.
        4,000원
        316.
        2018.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Cost-effective functional phosphor nanoparticles are prepared by introducing low-cost SiO2 spheres to rareearth phosphor (YVO4:Eu3+, YVO4:Er3+, and YVO4:Nd3+) shells using a sol-gel synthetic method. These functional nanoparticles are characterized by X-ray diffraction, X-ray photoelectron spectroscopy, transmission electron microscopy, and general photoluminescence spectra. The SiO2 sphere occupying the interior of the conventional phosphor is advantageous in significantly reducing the cost of expensive rare-earth phosphor nanoparticles. The sol-gel process facilitates the core–shell structure formation; the rare-earth shell phosphor has strong interactions with chelating agents on the surfaces of SiO2 nanoparticles and thus forms layers of several nanometers in thickness. The photoluminescence wavelength is simply tuned by replacing the active materials of Eu3+, Er3+, and Nd3+. Moreover, the photoluminescent properties of the core–shell nanoparticles can be optimized by manipulating the specific contents of active materials in the phosphors. Our simple approach substitutes low-cost SiO2 for expensive rare-earth-based phosphor materials to realize cost-effective phosphor nanoparticles for various applications.
        4,000원
        317.
        2018.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        PURPOSES: The purpose of this study is to analyze the characteristics of the weight values of evaluation items by traffic safety project type. METHODS: In general, a large-scale investment in projects such as the traffic safety project requires economic analyses to be performed in advance. However, there is an argument for considering special characteristics of the traffic safety project. Therefore, this study conducted characteristic analysis of the weight values of evaluation items. The analysis consisted of two steps. The first step was hypothesis verification using analysis of variance (ANOVA). In this process, the authors examined whether the weight of evaluation items is the same regardless of the traffic safety project type. Based on the first step's results, the authors proceeded to the second step. The objective of this step was to analyze how different the weight values are by traffic safety project type using an analytic hierarchy process. RESULTS: According to the ANOVA test results, the benefit to cost ratios have different weight values based on traffic safety project type at the 0.01 significance level. The policy evaluation items, such as the plans connection, resident opinion, and regional equity, also showed the same results except that the result for the related plans connection was statistically significant at the 0.05 level. Based on the first step's result, the AHP analysis in the second step showed that the traffic safety projects for vulnerable users and pedestrians have very low weight values in economic evaluation factors compared with other safety project types. The weight values for vulnerable users and pedestrians were 0.29 and 0.26, respectively, in economic evaluation items. On the other hand, the weight values for other safety project types were around 0.6. Among the policy evaluation items, resident opinion showed a higher weight value than other factors, such as connection and regional equity items. CONCLUSIONS: The social and economic impact of a traffic safety project varies by project type and project characteristics. Although the economic approach is overarching and a reasonable methodology is applied for large-scale projects, it should be noted that the safety issue, especially for transportation of vulnerable uses, requires a non-economical approach. Based on the analysis results, this study suggests that the priority of the projects should be determined by separating them into independent assessment groups depending on their characteristics.
        4,000원
        318.
        2018.01 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Active clay, bentonite and zeolite were used as porous materials for humidity controlling ceramic boards. The specific area and the pore volume of active clay were higher than bentonite and zeolite. The flexible strength of the gypsum board decreased with an increasing amount of porous material, and the flexible strength was lowest when active clay with a higher specific surface area than others porous materials was added. The specific surface area and total pore volume of ceramic boards containing porous material were highest at 102.25 m2/g, 0.142 cm3/g, respectively, when the active clay was added. In addition, as the amount of added porous materials increased, the specific surface area and total pore volume of the ceramic board increased, but the average pore diameter decreased. The addition of s porous materials with a high specific area and a large pore volume improved the moisture absorptive and desorptive performance of the ceramic board. Therefore, in this experiment, the moisture absorptive and desorptive properties were the best when active clay was added. Furthermore, as the amount of added porous materials increased, the moisture absorptive and desorptive properties improved. When 70 mass% of active clay was added to α-type gypsum, the hygroscopicity was the highest, about 300 g/m2, in this experiment.
        4,000원
        319.
        2018.01 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        We report on the efficient detection of NO gas by an all-oxide semiconductor p-n heterojunction diode structure comprised of n-type zinc oxide (ZnO) nanorods embedded in p-type copper oxide (CuO) thin film. The CuO thin film/ZnO nanorod heterostructure was fabricated by directly sputtering CuO thin film onto a vertically aligned ZnO nanorod array synthesized via a hydrothemal method. The transport behavior and NO gas sensing properties of the fabricated CuO thin film/ ZnO nanorod heterostructure were charcterized and revealed that the oxide semiconductor heterojunction exhibited a definite rectifying diode-like behavior at various temperatures ranging from room temperature to 250 oC. The NO gas sensing experiment indicated that the CuO thin film/ZnO nanorod heterostructure had a good sensing performance for the efficient detection of NO gas in the range of 2-14 ppm under the conditions of an applied bias of 2 V and a comparatively low operating temperature of 150 oC. The NO gas sensing process in the CuO/ZnO p-n heterostructure is discussed in terms of the electronic band structure.
        4,000원
        320.
        2017.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        For the purpose of developing new immunomodulatory agents from broccoli, ethanol extract (BCEE), hot water extract (BCHW), and crude polysaccharide (BCCP) were isolated from broccoli, and their immunomodulatory activities and chemical properties were examined. In the in vitro cytotoxicity analysis, BCHW and BCCP did not affect the growth of tumor cells and normal cells. Murine peritoneal macrophages stimulated with BCCP showed higher production of IL-6, IL-12, and TNF- α cytokines than those stimulated with BCHW. Also, BCHW and BCCP did not show proliferation of splenic lymphocytes. In the in vitro assay for intestinal immunomodulatory activities, only BCCP enhanced GM-CSF secretion and the bone marrow cell-proliferating activity via cells in Peyer’s patches at 1,000 μg/mL. Also, BCHW mainly contained 33.7% neutral sugars, such as arabinose, glucose, and galactose, and 30.7% uronic acid, and BCCP consisted of 42.6% neutral sugars, including arabinose, galactose, and glucose, and 50.5% uronic acid. The above results lead us to conclude that crude polysaccharide (BCCP) isolated from broccoli causes considerably high cytokine production in peritoneal macrophages and bone marrow cell proliferation, and the polysaccharide extraction process is indispensable for separation of new immunomodulatory agents from broccoli.
        4,000원