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        검색결과 41

        1.
        2024.10 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Silicon-based anode materials have attracted significant interest because of their advantages, including high theoretical specific capacity (~4,200 mAh/g), low working potential (0.4 V vs Li/Li+), and abundant sources. However, their significant initial capacity loss and large volume changes during cycling impede the application of silicon-based anodes in lithium-ion batteries. In this work, we propose a silicon oxide (SiOx) anode material for lithium-ion batteries produced with a magnesio-thermic reduction (MTR) process adopting Boryeong mud as a starting material. Boryeong mud contains various minerals such as clinochlore [(Mg,Fe)6(Si,Al)4O10(OH)8], anorthite (CaAl2Si2O8), illite [K0.7Al2(Si,Al)4O10(OH)2], and quartz (SiO2). The MTR process with Boryeong mud generates a mixture of amorphous silicon oxides (SiOx and SiO2), and magnesium aluminate which helps to alleviate the volume expansion of the electrode during charge/discharge. To observe the effects of these oxides, we conducted various analyses including X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier-Transformation infrared spectroscopy (FT-IR), Brunauer-Emmett-Teller (BET) and cyclic voltammetry (CV) galvanic cell testing. The amorphous SiO2 and MgAl2O4 suppressed the volume expansion of the silicon-based anode, and excellent cycle performance was achieved as a result.
        4,000원
        2.
        2020.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        1913년부터 2013년까지 국내에서 육성된 172품종에 대한 종실의 단백질, 지방 함량과 지방산 조성의 변이는 다음과 같다. 총 단백질 함량의 평균은 38.6%(31.6~45.3%), 지방함량의 평균은 18.4%(15.3~21.5%), 포화지방산 중 Palmitic acid의 함량은 평균11.11%(8.1~13.5%), Stearic acid의 함량은 평균 3.7%(1.9~5.4%), 불포화지방산인 Oleic acid의 함량은 평균 26.4%(13.1~41.8%), Linoleic acid의 함량은 평균 50.9% (37.2~63.0%), Linolenic acid의 함량은 평균 7.6%(5.7~9.8%), Linoleic(ω-6)/Linolenic(ω-3)acid의 비율은 평균 6.8(5.3~8.9)이여서, 포화지방산이 평균 14.8%(10.8~17.6%), 그리고 불포화 지방산 함량은 평균 84.9%(79.9~88.7%)이었다. 단백질 함량이 가장 높은 품종은 45.3%로 새단백콩이었으며, 지방함량이 가장 높은 품종은 21.5%를 함유한 늘찬콩이었다. 고 Oleic acid 함량인 동시에 저 Linoleic acid 함량인 검정콩1호는 양질의 지방산을 함유한 매우 유용한 품종이었다. 용도에 따른 단백질, 지방 지방산의 평균함량 중 단백질의 함량은 풋콩 및 올콩용 품종이 가장 높았고, 지방 함량은 장류용 품종이 가장 높았으며, 포화지방산은 장류용품종이 가장 낮았고, 불포화지방산의 함량은 풋콩 및 올콩용 품종이 가장 낮았다. ω-6/ω-3의 비율은 밥밑용 품종이 가장 낮았다. 종피색에 따라서는 단백질 함량은 녹색콩이 가장 높았으며 지방함량은 황색콩이 가장 높았다. 포화지방산은 황색콩과 검정콩이 가장 낮았으며, 불포화 지방산은 갈색콩이 ω-6/ω-3의 비율 또한 갈색콩이 가장 낮게 나타났다.
        4,000원
        3.
        2018.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The high theoretical energy density (2600 Wh kg−1) of Lithium-sulfur batteries and the high theoretical capacity of elemental sulfur (1672 mAh g−1) attract significant research attention. However, the poor electrical conductivity of sulfur and the polysulfide shuttle effect are chronic problems resulting in low sulfur utilization and poor cycling stability. In this study, we address these problems by coating a polyethylene separator with a layer of activated carbon powder. A lithium-sulfur cell containing the activated carbon powder-coated separator exhibits an initial specific discharge capacity of 1400 mAh g−1 at 0.1 C, and retains 63% of the initial capacity after 100 cycles at 0.2 C, whereas the equivalent cell with a bare separator exhibits a 1200 mAh g−1 initial specific discharge capacity, and 50% capacity retention under the same conditions. The activated carbon powder-coated separator also enhances the rate capability. These results indicate that the microstructure of the activated carbon powder layer provides space for the sulfur redox reaction and facilitates fast electron transport. Concurrently, the activated carbon powder layer traps and reutilizes any polysulfides dissolved in the electrolyte. The approach presented here provides insights for overcoming the problems associated with lithium-sulfur batteries and promoting their practical use.
        4,000원
        4.
        2018.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Unlike common nouns, proper nouns do not depend on the situation. So a proper noun is defined as either pointing to a particular object or pointing to a single object. In philosophy, these proper nouns have been known to play an important role in linking objects only to language and language extrinsic targets. For these reasons, however, proper nouns were not considered as important in foreign language education. However, after ‘the pragmatic turn of linguistics’ in the early 1960s, communication-oriented foreign language education became important. Because communication is closely related to the concept of culture, and culture and proper nouns are closely related. The purpose of this paper is to examine the status of proper nouns in the basic vocabulary of the second foreign language curriculum and how these proper nouns are presented in the College Entrance Trial Test/College Scholastic Ability Test. This paper seeks to analyze how often the same proper nouns are repeated in the test, how the proper nouns are translated, and whether such translations are consistent. Im Gegensatz zu gewöhnlichen Substantiven sind Eigennamen nicht von der Situation abhängig. Ein Eigenname ist also definiert als entweder auf ein bestimmtes Objekt zeigend oder auf ein einzelnes Objekt zeigend. In der Philosophie ist bekannt, dass diese Eigennamen eine wichtige Rolle bei der Verknüpfung von Objekten nur mit extrinsischen Zielsetzungen von Sprache und Sprache spielen. Aus diesen Gründen wurden Eigennamen im Fremdsprachenunterricht jedoch nicht als wichtig erachtet. Nach der “pragmatischen Wende der Linguistik” in den frühen 1960er Jahren wurde jedoch der kommunikationsorientierte Fremdsprachenunterricht wichtig. Es ist wichtig zu beachten, dass es eine enge Beziehung zwischen Kommunikation und Kultur gibt. Kultur und Eigennamen haben miteinander zu tun. Der Zweck dieses Artikels ist es, den Status von Eigennamen im Vokabular des zweiten Fremdsprachenlehrplans zu untersuchen und wie diese Eigennamen im College Entrance Trial Test / College Scholastic Ability Test dargestellt werden. Diese Arbeit versucht zu analysieren, wie oft dieselben Eigennamen im Test wiederholt werden, wie die Eigennamen übersetzt werden und ob solche Übersetzungen konsistent sind.
        5,500원
        5.
        2017.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The objective of this study was to investigate ELF-MF exposure levels of the elderly groups in their living environments using 24-hour personal measurement. In addition, EMF risk perception was investigated. Through evaluations of ELF-MF exposure levels in the proximity of the participants of 58 elderly groups, it was found that TWAam was 1.31 mG (TWAgm: 0.84). ELF-MF exposure levels of the elderly group that live in the proximity of a non-visible power line was high, but there were no statistically significant differences between the non-visible power line elderly group and visible power line elderly group. Moreover, there were no statistically significant differences in ELF-MF exposure according to gender, age, city classification, incomes, residence type, and size. The results showed that the perception of the ELF-MF was very low, as indicated by more than roughly 58.6% of the elderly surveyed saying that they did not know what ELF-MF was. In addition, there was no awareness among the group of how to avoid behavior of EMF from some electric equipment and facilities. Thus, these results will provide useful data for the determination of ELF-MF management and risk communication methods in the living environment for elderly people.
        4,000원
        6.
        2016.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The objective of this study was to investigate ELF-MF exposure levels in infant living environmental spaces at daycare centers. To achieve the objective of the study, we surveyed ELF-MF levels using EMDEX II at daycare centers from October 2013 to October 2014. The ELF-MF level of 53 daycare centers in terms of arithmetic mean (AM) and geometric mean (GM) were 0.59 ± 0.76 mG and 0.33 mG, respectively. And the ELF-MF level of 260 daycare center classrooms was 0.50 ± 0.71 mG (GM: 0.28 mG). The exposure levels of ELF-MF for all daycare centers were far below the recommended standards cited in guidelines in Korea (833 mG) and international reference levels proposed by WHO or ICNIRP (2,000 mG). Furthermore, we discovered out that as distance increased, ELF-MF emission levels decreased significantly in all electrical instruments. Below the 2 mG ELF-MF levels when an electrical instrument moved away stage 1 (Grade). Thus, these results will provide useful data for the determination of ELF-MF management and reduction methods at infant daycare centers.
        4,000원
        7.
        2016.11 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The objective of this study was to investigate the physicochemical characteristics of bear, pig, and cow biles to determine their authenticities for safe food distribution. The main bile acids of bear bile were tauroursodeoxycholic acid and taurochenodeoxycholic acid, while glycochenodeoxycholic acid and taurochenodeoxycholic acid for pig bile and taurocholic acid and glycocholic acid for cow bile were majorly detected by HPLC analysis. HPLC analysis was effective in monitoring of several samples imported as bear bile if employed to determine the authenticity of each bile. After the analysis of fatty acid composition by GC analysis, the ratio of the oleic acid of bear bile was relatively low compared to pig and cow biles. The ratio of the linoleic acid of bear bile was also similar to pig bile, whereas it had a tendency to be high compared to cow bear. The genetic analysis of the imported bile samples was mostly in agreement with the results of HPLC and GC analysis to identify the origin of imported biles. Finally, this study on the identification of bile origin by physicochemical analysis can give basic information to monitor the origin of biles and further to establish a reliable system for bear bile distribution.
        4,000원
        8.
        2016.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The objective of this study was to assess RF-EMF exposure levels in indoor daycare centers in a Metropolitan city. RF-EMF measurements were collected and surveyed from 50 volunteer daycare centers in the Korea between October 2013 and October 2014. Through our research, it was found that the main exposure source for indoor daycare centers is the frequency bands for TV and Radio broadcasting (FM: 88.1~107.9 MHz), mobile phone (869~894 MHz, 1840~1870 MHz, 1885~2170 MHz), wireless LAN and home electronics, etc., including TRS, Wireless Data Communication. The RF-EMF exposure levels for all daycare centers were far below the recommended standards of EMF Guideline Korea and international reference levels proposed by ICNIRP (International Commission on Non-Ionizing Radiation Protection). However, in terms of long term health effects some uncertainty exists, and thus minimizing exposure may reduce this uncertainty. The data we collected will be useful data for determining RF-EMF management and risk communication at daycare centers.
        4,000원
        9.
        2016.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Radon (222Rn) gas is a main source of ionizing radiation of natural origin. It typically moves up through the ground to the air above and into building or home through cracks and other holes in the foundation. Significantly, the Surgeon General has warned that radon is the second leading cause of lung cancer in the United States today. This survey covers the determination of indoor radon concentrations at home from 2013 to 2014 in some areas of Gangwondo, every three months (seasonal) during one year using an alpha-track detector. The results showed that the annual average concentration of indoor radon was 84.5 Bq/m3 (GM: 64.5 Bq/m3) at homes. Indoor radon level was the highest in winter and the lowest in summer. Geometric mean radon concentration in winter was 1.03~2.58 times higher than other seasons. The data obtained from this study provide a basis for the preparation of legal regulation and public health protection manuals in this area.
        4,000원
        10.
        2016.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        According to the regulations of the Korean Animal and Plant Quarantine Agency (QIA), offals include a greater diversity of internal organs than do those of other nations. The present study was conducted to investigate the microbiological quality of diverse edible offal products from pig and cattle slaughterhouses in Korea by performing aerobic plate counts (APCs) and E. coli counts. There were significant differences in E. coli values between red offal and white offal in both pigs and cattle. Significant differences in APCs were also observed between partial red offal and white offal of pigs (P < 0.05). However, no significant differences in APCs between red offal and white offal of cattle. The most frequently detected foodborne pathogen was Staphylococcus aureus (5.6% prevalence in pig offal and 12.5% % prevalence in cattle offal) followed by Clostridium perfringens (11.1 and 7.1%, respectively) and Salmonella (5.6% and 7.1%, respectively). None of the offal samples tested positive for E. coli O157:H7.
        4,000원
        11.
        2010.10 구독 인증기관·개인회원 무료
        This study is based on specimens which had been collected from Jeollabuk-do, Chungcheonbuk-do and Gyeonsangnam-do provinces in July 1994 through September 2009. As a result of this study, Cunaxa potchensis and C. mageei were identified and newly recorded from Korea.
        12.
        2006.06 KCI 등재 구독 인증기관·개인회원 무료
        β-Hydroxy-β-methylglutaryl coenzyme A reductase(HMG-CoA reductase, E.C. 1.1.1.34) is known to be rate-limiting enzyme in cholesterol biosynthesis. HMG-CoA reductase inhibitor is very useful in the remedy or precaution of hyperlipidemia. The methanol extracts of Pholiota adiposa ASI 24018 showed the highest HMG-CoA reudctase inhibitory activity of 55.8%. The HMG-CoA reductase inhibitor of Pholiota adiposa ASI 24018 was maximally extracted when it was treated with methanol at 30℃ for 12hrs. After purified the HMG-CoA reductase inhibitor by systematic solvent extraction, LH-20 gel column chromatography and RP-HPLC, finally obtained the HMG-CoA reductase inhibitor with an activity of IC50 6.8ug. Molecular weight of the purified HMG-CoA reductase inhibitor was 765.4Da by LC-Mass, NMR, FT-IR, UV spectrometry.
        13.
        2005.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, AR (aromatic resin) pitch was employed as the matrix-precursor for carbon/carbon composite because it exhibits much higher coke yield than coal tar pitch. As a result, a fabrication process of carbon/carbon composites can be shortened. It has been known that the pitches may cause swolling problem during the carbonization process. In order to restrain the swelling occurrence, a small quantity of carbon black was added to the AR pitch. Due to addition of carbon black the swelling was decreased largely and the perform can be infiltrated with the AR pitch. The densification efficiency of the performs was compared with various matrix-precursors. The coke yield of matrixprecursors, the morphology and the degree of graphitization of carbon matrix were analyzed.
        4,000원
        14.
        2003.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Carbon/carbon composites are ideal candidates for a number of aerospace applications including structural materials for advanced vehicles, leading edges, structures of re-entry and hypersonic vehicles and propulsion systems. One serious defect for such application of the carbon/carbon composites is their poor oxidation resistance in high temperature oxidizing environments. SiC coating was employed to protect the composites from oxidation. It is mechanically and chemically stable under extreme thermal and oxidative environments, provides good adhesion to the substrate, and offers good thermal shock resistance. The SiC layer on the nozzle machined from the carbon/carbon composites was formed by pack-cementation method. Then, erosion characteristic of SiC coated carbon/carbon nozzle was examined by combustion test using a liquid rocket motor. The erosion rates were measured as function of combustion pressure, ratio of oxygen to fuel, combustion time, density of the composites and geometry of reinforced carbon fibre in the composites. The morphology change of the composites after combustion test was investigated using SEM and erosion mechanism also was discussed.
        4,000원
        15.
        2003.08 구독 인증기관 무료, 개인회원 유료
        The six kinds of natural factors(It refers to wind, cold, summer-heat, dampness, dryness and fire.) is constantly moving to maintain the balance of whole climate of one year. Four seasons are the largest mediation of whole climate of one year. The cold and the heat have the relationship of mutual intervention. The dampness and the dryness have it also. In this process they raise various climate appearance. And that various climate appearance influence the whole lives on the earth. This paper is concerned with the classification of them.
        4,800원
        16.
        2003.08 구독 인증기관 무료, 개인회원 유료
        Five elements motion and six kinds of natural factors influence not only human disease but also difference of medicine effect. Because the climate of summer is very hot, that is easy to increase the properties of hot medicines, a doctor must be careful to use it in summer. Also the climate of winter is very cold, that is easy to increase the properties of cold medicines, a doctor must be careful to use it in winter. But in the certain conditions to use diaphoretics or purgatives, in spite of that regulation a doctor can use them.
        4,000원
        18.
        2023.11 서비스 종료(열람 제한)
        In KAERI, the nuclide management technology is currently being developed for the reduction of disposal area required for spent fuel management. Among the all fission products of interest, Cs, I, Kr, Tc are considered to be significantly removed by following mid-temperature and hightemperature treatment, however, a difficulty of real spent-fuel thermal treatment experiment limits the development of such thermal treatment. The test employing SimFuel (Simulated Spent Fuel) can be an alternative for such condition, however, the fabrication of SimFuel containing semivolatile species such as Cs, I and Re (substitute for Tc) was not achieved for conventional sintering method since such species are easily removed during hot temperature treatment. In this study, for the prevention of volatilization of such species and the inclusion of semi-volatile species in fabrication of SimFuel, argon-based high pressurizing up to Max 100 bar was considered to be applied in high temperature treatment. For this, lab-scale hot-isostatic press applicable up to 1,500°C was fabricated and is being waiting for the approval for high-pressure test. After approval of license, UO2 baesd SimFuel containing CsI will be fabricated and its micro-structure and composition will be evaluated through SEM-EDX and XRD
        19.
        2023.05 서비스 종료(열람 제한)
        The stabilization techniques are highly required for damaged nuclear fuel to strengthen safety in terms of transportation, storage, and disposal. This technique includes recovering fuel materials from spent fuel, fabrication of stabilized pellets, and fabrication of fuel rods. Thus, it is important to identify the leaching behavior of the stabilized pellets to verify their stability in humid environments which are similar to storage conditions. In this study, we introduce various leaching experiment methods to evaluate the leaching behavior of the stabilized pellets, and determine the most suitable leaching test methods for the pellets. Also, we establish the leaching test conditions with various factors that can affect the dissolution and leaching behavior of the stabilized pellets. Accordingly, we prepare the simulated high- (55 GWd/tU) and low- (35 GWd/tU) burnup nuclear fuel (SIMFUEL) and pure UO2 pellets sintered at 1,550°C and 1,700°C, respectively. Each pellet is placed in a vessel and filled with DI water and perform the leaching test at three different temperature to verify the leaching mechanism at different temperature range. Based on the standard leaching test method (ASTM C1308-21), the test solution is removed from the pellet after specific time intervals and replaced in the fresh water, and the vessel is placed back into the controlled-temperature ovens. The test solutions are analyzed by using ICP-MS.
        20.
        2023.05 서비스 종료(열람 제한)
        The Ag0-containing sorbents synthesized by Na, Al, and Si alkoxides have higher maximum iodine capture capacity and textural properties than zeolite-based Ag0-containing sorbents. However, these sorbents were prepared in the form of granules via a step for cutting cylindrical alcogels. Since asmade sorbents decreased packing density, they must be additionally crushed and then classified into an appropriate size for increasing packing density. The bead formation in the step of sol-gelation could bring about the simplification of sorbent preparation process and an improvement of packing density. In the Na, Al, and Si alkoxides as starting materials, sol solution was hydrophilic and lower density than vegetable oil, which transformed sol droplets to sol-gel beads. Thus, in these precursors, sol droplets, which must be sprayed by single nozzle placed at bottom side of oil column, can rise up through oil column. Acetic acid (HOAc) was used as the catalyst for the hydrolysis of Na alkoxide (TEOS) and gelation of the Na+AlSi-OH alcosol. For obtaining sol-gel beads, experiments were performed by the flowrate change of sol solution and HOAc at different nozzle sizes using soybean oil column of 1 m in length. At a sol/HOAc flowrate ratio of 3.85, some Na+AlSi-OH alcogel beads were obtained. After the Ag/Na ion-exchange, Ag content in Ag+AlSi-OH hydrogel was low due to reaction between Na+ and HOAc during sol-gelation and aging step. The Ag+AlSi-OH hydrogel with high Ag content could be prepared by Na addition. After the solvent exchange and drying at ambient pressure, the bead sorbents had higher Ag0 content and larger pore size than granular sorbents. However, further experiments are needed to increase yield rate in bead sorbent.
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