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        검색결과 19

        2.
        2019.12 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        We present the results of near-infrared imaging observations of the galaxy overdensity around the z = 1.44 radio-loud active galactic nucleus (AGN) 6CE1100+3505, which was carried out with the purpose of sampling the redshifted Hα emission from the actively star-forming galaxies that could constitute the overdensity. The existence of the structure around this AGN was spectroscopically confirmed by previous grism observations which are however limited to the central region. Using the CH4Off narrow/medium-band and H broad band filters in the Wide Infrared Camera (WIRCam) on the Canada-France-Hawaii Telescope (CFHT), we constructed a sample of objects that show a flux excess in the CH4Off band due to line emission. The emission line flux is ∼ 4.9 × 10−16 erg s−1 cm−2 , corresponding to a star formation rate (SFR) of ∼ 50 M⊙ yr−1 for galaxies at redshifts z ∼ 1.4. None of the galaxies with medium-band flux excess is located within 1 Mpc from the central AGN, and there is no evidence that the selected galaxies are associated with the proposed cluster. Along with the star formation quenching near the center that was found from the previous grism observations, the lack of extreme starbursts in the structure suggests that at z ∼ 1.4, overdense regions are no longer favorable locations for vigorous star formation.
        4,000원
        4.
        2018.04 구독 인증기관·개인회원 무료
        환경부 지정 보호지역인 특정도서는 현재 249개소로 이들을 대상으로 지형․경관, 지질, 식생, 동・식물상 및 해안무척 추동물, 해조류 분류군 대상으로 1차 특정도서기본계획(‘05~’14) 이후 2차 특정기본계획(‘15~’24)에 따라 매년 10~15개 씩 정밀조사가 수행되고 있다. 특정도서의 곤충조사는 2006~2008년 3년간 39개 도서를 제외하고 전무하였다. 특정도서 의 지정사유 중 자연경관․지질의 우수성이 가장 높고 식생이 우수가 다음으로 높아 시간이 지남에 따라 식생과 관련된 해충 및 외래종의 기착지로도 이용될 수 있는 특성을 가지고 있어 2015년부터 곤충에 대한 조사가 이루어지고 있다. 본 연구는 2016년 인천광역시 옹진군 일대 소초지도, 신도, 어평도, 항도, 뭉퉁도, 서만도, 할미염 7개 특정도서에 대한 곤충상 및 군집분석 결과와 각 도서별 과거 2007년 보고된 곤충상을 비교한 결과를 보고하는 바이다.
        5.
        2017.06 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        We study the angular correlation function of bright (Ks ≤ 19.5) Extremely Red Objects (EROs) selected in the Subaru GTO 2 deg2 field. By applying the color selection criteria of R − Ks > 5.0, 5.5, and 6.0, we identify 9055, 4270, and 1777 EROs, respectively. The number density is consistent with similar studies on the optical − NIR color selected red galaxies. The angular correlation functions are derived for EROs with different limiting magnitude and different R −Ks color cut. When we assume that the angular correlation function w() follows a form of a power-law (i.e., w() = A−), the value of the amplitude A was larger for brighter EROs compared to the fainter EROs. The result suggests that the brighter, thus more massive high-redshift galaxies, are clustered more strongly compared to the less massive galaxies. Assuming that EROs have redshift distribution centered at hzi ∼ 1.1 with z = 0.15, the spatial correlation length r0 of the EROs estimated from the observed angular correlation function ranges ∼ 6-10 h−1Mpc. A comparison with the clustering of dark matter halos in numerical simulation suggests that the EROs are located in most massive dark matter halos and could be progenitors of L∗ elliptical galaxies.
        4,000원
        6.
        2017.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Biodegradable epoxy (B-epoxy) was prepared from diglycidyl ether of bisphenol A and epoxidized linseed oil. The mechanical properties of B-epoxy composites reinforced with multi-walled carbon nanotubes (MWCNTs/B-epoxy) were examined by employing dynamic mechanical analysis, critical stress intensity factor (KIC) tests, and impact strength tests. The electromagnetic interference shielding effectiveness (EMI-SE) of the composites was evaluated using reflection and absorption methods. Mechanical properties of MWCNTs/B-epoxy were enhanced with an increase in the MWCNT content, whereas they deteriorated when the MWCNT content was >5 parts per hundred resin (phr). This can likely be attributed to the entanglement of MWCNTs with each other in the B-epoxy due to the presence of an excess amount of MWCNTs. The highest EMI-SE obtained was ~16 dB for the MWCNTs/B-epoxy composites with a MWCNT content of 13 phr at 1.4 GHz. The composites (13 phr) exhibited the minimum EMI-SE (90%) when used as shielding materials at 1.4 GHz. The EMI-SE of the MWCNTs/B-epoxy also increased with an increase in the MWCNT content, which is a key factor affecting the EMI-SE.
        4,000원
        7.
        2017.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, a finite element analysis approach is proposed to predict the fluid-structure interaction behavior of active materials for lithium-ion batteries (LIBs), which are mainly composed of graphite powder. The porous matrix of graphite powder saturated with fluid electrolyte is considered a representative volume element (RVE) model. Three different RVE models are proposed to consider the uncertainty of the powder shape and the porosity. Pwave modulus from RVE solutions are analyzed based on the microstructure and the interaction between the fluid and the graphite powder matrix. From the results, it is found that the large surface area of the active material results in low mechanical properties of LIB, which leads to poor structural durability when subjected to dynamic loads. The results obtained in this study provide useful information for predicting the mechanical safety of a battery pack.
        4,000원
        10.
        2013.09 구독 인증기관 무료, 개인회원 유료
        Transgenic chickens have been spotlighted as an highly potent bioreactor for their fecundity, short generation time, and eggs associated with mass production of protein. In this study, we generated transgenic chickens exhibiting oviduct specific expression of human growth hormone fused to human transferrin for oral administration. Gene of the modified growth hormone located at downstream ovalbumin promoter (∼3.6 kb) was introduced to stage X blastodermal cell employing retrovirus vector system. Several transgenic chickens were successfully generated. However, genomic analyses showed unexpected deletion within the transgene. The modification of the transgene seemed to occur during germ cell formation because the deletion was detected only from the sperm DNA of the G0 founder animal. There was no evidence of deletion in the somatic cell DNA samples of the same chicken. Consequently, same pattern of the deletion was confirmed in both somatic and germ cells of the G1 progeny.
        4,000원
        11.
        2012.05 구독 인증기관·개인회원 무료
        This study was conducted to identify an insect species in Genus Ostrinia (Lepidoptera: Crambidae) that gave serious damage to the red bean, Vigna angularis. The species has ever been described as O. zaguliaevi in the previous presentation (Jung et al., 2010). Because, however, inconsistent information has been recognized for the species, we reviewed characteristics in morphological, molecular and sex pheromone levels, and host-range. Male genitalia had 3-lobed uncus and tibia of midleg showed massive type. The morphology indicated that the species might be one of O. zaguliaevi, O. scapulalis and O. zealis. Partial nucleotide sequences of cytochrome oxidase subunit Ⅰ(COⅠ) and Ⅱ genes were not identical with those of the 3 species in GenBank, respectively. The deduced amino acid sequence of COⅠ was not identical with that of O. zealis. In the 23 analyses that sex pheromones were checked, (Z)-9-tetradecenyl acetate, which was reported in the sex pheromone components of both O. zaguliaevi and O. zealis, was not detected at all. An intensive study in Japan has reported that the feeding habit of O. scapulalis is polyphagous, while that of O. zaguliaevi is monophagous (only in Petasites japonicus) (Ishikawa et al., 1999). After considering all these information, we concluded that it is reasonable to decide that the insect species in the red bean in Korea is O. scapulalis.
        12.
        2011.12 구독 인증기관 무료, 개인회원 유료
        Pneumatosis cystoides intestinalis (PCI) is a rare condition characterized by multiple intramural pockets of gas filled cysts in the intestinal wall. PCI is usually found incidentally on an imaging study. Many different causes of PCI have been suggested, including mechanical, pulmonary, and bacterial causes. Treatment is usually conservative, including oxygen and antibiotic therapy. We report on two cases of PCI, without symptoms, in a 62-year-old male and a 72-year-old male. Computed tomography showed numerous, small, round, and air densities on the sigmoid colon. Colonoscopy showed numerous, variable-sized, sessile polypoid, balloon-like distended, and protruding subepithelial masses covered with normal colonic mucosa on the sigmoid colon. We observed that when the cyst was stuck with a needle, the size of the cyst was reduced and showed a flat termination. Therefore, we made a diagnosis of PCI and report on the case with references.
        4,000원
        13.
        2009.05 구독 인증기관·개인회원 무료
        DNA barcode is known to be successfully applied in identification on the members of Insecta. In recent studies, however, it was known that the DNA approach may fail in several taxa with following cases: (1) very recent speciation and hybridization, (2) recent diverged groups with complex gene histories, (3) the spread of maternally transmitted bacteria, (4) adding more than one geographical race and at least one congener, (5) different levels of dispersal. In this study, we taxonomically review on the Korean Hatchiana using the morphological data and DNA barcodes. In morphology, they are distinct from each other by the characteristics of body coloration, eye, pronotum, scutellum, and aedeagus. In molecular data, however, the interspecific sequence distance ranged from 0.0-3.4%. This result is caused by H. glochidiatus, of which the sequence divergence is 0.2-2.8% in H. rosinae, 0.8-2.6% in H. baekripoensis, and 0.0-3.3% in H. jirisanensis. Also, H. glochidiatus produces mixed-clusters with H. rosinae and H. jirisanensis in NJ phenogram. Through this presentation, therefore, we discuss on why the four Korean Hatchiana species distinct by morphological characters produce mixed-clusters in DNA barcoding.
        14.
        2016.12 KCI 등재 서비스 종료(열람 제한)
        최근 다엽콜리메이터를 부착한 선형가속기를 이용한 방사선수술의 빈도가 점차 높아지고 있다. 이러한 정교한 방사선 수술은 소조사면 내에 고선량의 방사선이 집중적으로 조사되기 때문에 체계적이고 정확한 정도관리가 필수적이다. 본 연구는 PIB(Particle in Binder) 방식 중 침전법을 이용하여 400 ㎛ 두께의 요오드화납(PbI2)과 요오드화수은(HgI2) 광도전체 센서 시편를 제작하였다. 제작된 시편의 전기적 특성은 암전류, 출력전류, 응답특성 및 선형성을 평가하였다. 평가 결과, HgI2 가 우수한 신호발생량과 선형성을 보였다. 끝으로, 두께에 따른 HgI2 센서의 신호반응 특성 결과, 400 ㎛ 두께에서 신호발생효율이 가장 높았고, ±2.5 % 이내의 우수한 재현성을 보였다.