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        검색결과 21

        1.
        2024.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The development of thermoelectric (TE) materials to replace Bi2Te3 alloys is emerging as a hot issue with the potential for wider practical applications. In particular, layered Zintl-phase materials, which can appropriately control carrier and phonon transport behaviors, are being considered as promising candidates. However, limited data have been reported on the thermoelectric properties of metal-Sb materials that can be transformed into layered materials through the insertion of cations. In this study, we synthesized FeSb and MnSb, which are used as base materials for advanced thermoelectric materials. They were confirmed as single-phase materials by analyzing X-ray diffraction patterns. Based on electrical conductivity, the Seebeck coefficient, and thermal conductivity of both materials characterized as a function of temperature, the zT values of MnSb and FeSb were calculated to be 0.00119 and 0.00026, respectively. These properties provide a fundamental data for developing layered Zintl-phase materials with alkali/alkaline earth metal insertions.
        4,000원
        3.
        2022.10 구독 인증기관·개인회원 무료
        Cement is widely used as representative industrial material. In Korea, about 50 million tons of cement are consumed every year. In the manufacture of cement, raw materials containing NORM such as fly ash and bauxite are used. Therefore, the workers can be subjected to radiation exposure. The major exposure pathway in NORM industries is internal exposure due to inhalation of aerosol. Internal radiation dose due to aerosol inhalation varies depending on physicochemical properties of the aerosol. Therefore, the objective of this study was to investigate aerosol properties influencing inhalation dose in cement industries. In this study, aerosol properties were measured for two cement manufacturers. A particulate size distribution and concentration at various processing areas in cement manufacturing industries in Korea were analyzed using a cascade impactor. The mass density of raw materials and byproducts were measured using pycnometer. Shape of particulates was analyzed using SEM. The radioactivity concentration of Ra-226, Ra-228 for U/Th decay series was measured using HPGe. Particulate concentration by size was distributed log-normally with maximum at particle size about 7.2 μm in manufacturer A and 5.2 μm in manufacturer B. The mass density of fly ash and cement were 2.3±0.06, 3.2±0.02 g/cm3 respectively in manufacturer A. In manufacturer B, the mass density of bauxite and cement were 3.4±0.02, 2.9±0.01 g/cm3 respectively. The shape of particulates appeared as spherical shape in manufacturer A and B regardless of sampling area. Thus, a shape factor of unity could be assumed. The radioactivity concentrations of Ra-226, Ra-228 were 82±9, 82±8 Bq/kg for fly ash, and 25±4, 23±3 Bq/kg for cement in manufacturer A. In manufacturer B, the radioactivity concentrations of Ra-226, Ra-228 were 344±34, 391±32 Bq/kg for bauxite, and 122±13, 145±12 Bq/kg for cement. The radioactivity concentrations of Ra-226, Ra-228 in cement were less than raw materials such as fly ash and bauxite. It is because the dilution of the radioactivity concentration occurred during mixing with other raw materials in cement production process. This study results will be used as database for accurate dose assessment due to airborne particulate inhalation by workers in cement industries.
        8.
        2017.10 구독 인증기관·개인회원 무료
        This study was carried out to investigate insect community structure from different habitats in Baengnyeong island.We performed day and night collection at two different habitats (mountain, rural area) of Baengnyeong island from Mayto September in 2015. A total of 2,879 individuals of 404 species, 81 families belonging to 10 orders were collectedand identified. A dominant species was Idisia ornata Pascoe (Tenebrionidae) despite a very low percentage (6.04%) ofthe species among the catches. Results of independent t-test showed a significant high (p<0.001) of species richness onmountain. Also, seasonal results of ANOVA (Analysis of variance) were significantly influential with species abundanceand species richness. The result of NMDS analysis showed that the community structure of the insects from the mountainis different with rural area.
        9.
        2015.10 구독 인증기관·개인회원 무료
        This study was carried out to investigate insect community structure from different habitats. We performed day and night collection at three different habitats (mountain, coast and rural area) of island Deokjeok, island Soya and island Mungap from May to September in 2014. A total of 3,482 individuals of 725 species, 119 families belonging to 10 orders were collected and identified. A dominant species was Corymbia rubra (Cerambycidae) despite a very low percentage of the species among the catches. Results of ANOVA test showed a significant effect of habitats typeon species diversity. Also, combination of seasons and habitats types were significantly influential with species abundance and species diversity. Indicator species analysis (ISA) result identified 121 significant (p < 0.05) indicator species; one species for the habitats cluster, 93 species for the season cluster and 27species for combination of habitats with seasons.
        10.
        2015.04 구독 인증기관·개인회원 무료
        An insect faunal survey was carried out to investigate insect community structure along the vegetation community to monitor insect species in forest ecosystem. We performed day and night collections from June to August along three vegetation communities of Is. Nam-hae in 2014: the first stand with Pinus thunbergii, the second P. thunbergii with Quercus serrata and the third P. thunbergii with various Quercus species. In total 2,259 individuals of 532 species, 99 families, 13 orders are identified. Cluster Analyses (CA) showed that all three vegetation communities were relatively similar between vegetation community types. According to indicator species analysis (ISA) result, nine significant indicator species were identified (p < 0.05); five species were found to be affected by the vegetation cluster and four species the month cluster.
        11.
        2014.10 구독 인증기관·개인회원 무료
        Insect pollinators of the endanger orchid Cypripedium japonicum were surveyed and identified during two years, as a part of a conservation project of the orchid at Jukyeup-san and Hwaak-san (Mt.), South Korea. In total 40 individuals of 16 species in 4 families were identified. The dominant family was Halictidae, and Lasioglossum exiliceps Vachal visited the most frequently C. japonicum during the surveys. The average visiting frequency was 2.5 individuals per hour and the highest 4.3, from 12:00 – 13:00 in a day. After 15:00 insects did not visit the flowers at all. However, all of the visiting insects were found to not carry a pollinium or pollens of the orchard on their bodies; pollen carryover by any of the visiting insects did not occur at all. The orchid seems to require certain pollinators in particular body thickness due to its unique pollination mechanism. The orchid has two exit route openings, around 1 cm in diametre, where the entrapped insects can exit and an anther is situated just in front of each opening. It was inferred that a pollen carrier should be around 1 cm in body thickness. Therefore, the candidate species as the proper pollen carriers can be Tetralonia nipponensis Perez, Xylocopa appendiculata circumvolans Smith and Bombus consobrinus Dahlbom among the surveyed visitors.
        15.
        1996.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        배관을 구속시키기 위한 원동형 배관 지지대 (Trunnion Pipe Support) 까 부착된 uß 간의 응-딱해석플 위하 여 유한요소해석을 사용하였다. 해석션파로 부터 얻어진 응역은 두께에 대한 평칸(막응역) 넷 선행 응→박( ""," 힘응력) 으로 분류 되었므며, 분류된 응벽값은 암략에 악한 언차응략겨l 수 (B 1 ) 와 이자응역겨l 수 (C 1 ) , 보멘트에 의한 일차응력계수 (B" , Bιr) 와 이차응략셰수 (C객, C!T) 플- 추성하시 위하여 ASME Code 에 성의뭔것파 일치 하게 해석되었다 무차원의 함수로써 응력 세수에 대한 경험식 얀 새만히기 위하여 여서 ~i~ l;'l 의 해삭 2~ 수행하 였다.
        4,000원
        19.
        2003.02 KCI 등재 서비스 종료(열람 제한)
        To analyze the effect of 1RS chromosome segment on anther culture efficiency in wheat, 44 cultivars released from several countries were evaluated. The cultivars applied for this investigation came from several regions and it was necessary to confirm cult
        20.
        2002.12 KCI 등재 서비스 종료(열람 제한)
        A new covered barley variety, 'Daeyeonbori' was developed from the cross between Milyangketbori, a stabile for machine harvest, and Olbori by the barley breeding team in the National Yeongnam Agricultural Experiment Station (NYAES) in 1999. An elite line,
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