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        검색결과 16

        1.
        2023.10 구독 인증기관·개인회원 무료
        Understanding the landscapes and the elements that make up the landscapes can help us understand the entire natural ecosystems and biodiversity. Landscape ecology has been studied since the past. however, many studies are conducted on single landscapes, and comparative studies between landscapes are few. We compared insect species diversity and community structure within a single plant community across landscapes and habitat. Additionally, identify environmental factors that affect diversity. Our results showed that above-ground and below-ground insect communities were clearly distinguished. Additionally, species diversity was high below-ground in all landscapes. Insect community structures across landscapes did not differ in above-ground. However, below-ground, the urban was differentiated from the forest and agricultural land. We identified the urbanization indices GMIS and PHBASE as factors responsible for these difference.
        2.
        2023.09 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        This study investigated the growth behavior and characteristics of compounds formed at the interface between a liquid Al-Si-Cu alloy and solid cast iron. Through microstructural analyses, it was observed that various AlFe and AlFeSi phases are formed at the interface, and the relative proportion of each phase changes when small amounts of strontium are added to the Al alloy. The results of the microstructural analysis indicate that the primary phases of the interfacial compounds in the Al-Si-Cu base alloy are Al8Fe2Si and Al4.5FeSi. However, in the Sr-added alloys, significant amounts of binary AlFe intermetallic compounds such as Al5Fe2 and Al13Fe4 formed, in addition to the AlFeSi phases. The inclusion of Sr has a slight diminishing effect on the rate at which the interfacial compounds layer thickens during the time the liquid Al alloy is in contact with the cast iron. The study also discusses the nano-indentation hardness and micro-hardness of the interfacial phases.
        4,000원
        3.
        2023.01 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        In order to broaden the range of application of light weight aluminum alloys, it is necessary to enhance the mechanical properties of the alloys and combine them with other materials, such as cast iron. In this study, the effects of adding small amounts of Cu and Zr to the Al-Si-Mg based alloy on tensile properties and corrosion characteristics were investigated, and the effect of the addition on the interfacial compounds layer with the cast iron was also analyzed. Although the tensile strength of the Al-Si-Mg alloy was not significantly affected by the additions of Cu and Zr, the corrosion resistance in 3.5 %NaCl solution was found to be somewhat lowered in this research. The influence of Cu and Zr addition on the type and thickness of the interfacial compounds layer formed during compound casting with cast iron was not significant, and the main interfacial compounds were identified to be Al5FeSi and Al8Fe2Si phases, as in the case of the Al-Si-Mg alloys.
        4,000원
        5.
        2021.03 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Cr-Si based alloys are not only excellent in corrosion resistance at high temperatures, but also have good wear resistance due to the formation of Cr3Si phase, therefore they are promising as metallic coating materials. Aluminum is often added to Cr-Si alloys to improve the oxidation resistance through which stable alumina surface film is formed. On the other hand, due to the addition of aluminum, various Al-containing phases may be formed and may negatively affect the heat resistance of the Cr-Si-Al alloys, so detailed investigation is required. In this study, two Cr-Si-Al alloys (high-Si & high-Al) were prepared in the form of cast ingots through a vacuum arc melting process and the microstructural changes after high temperature heating process were investigated. In the case of the cast high-Si alloy, a considerable amount of Cr3Si phase was formed, and its hardness was significantly higher than that of the cast high-Al alloy. Also, Al-rich phases (with the high Al/ Cr ratio) were not found much compared to the high-Al alloy. Meanwhile, it was observed that the amount of the Al-rich phases reduced by the annealing heat treatment for both alloys. In the case of the high temperature heating at 1,400 oC, no significant microstructural change was observed in the high Si alloy, but a little more coarse and segregated AlCr phases were found in the high Al alloy compared to the cast state.
        4,000원
        8.
        2019.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, we studied the alignment characteristics of liquid crystal on polyimide substrate when irradiated with ion beam in oblique direction on uniformly coated polyimide substrate. The inclined irradiation angle of the ion beam was set to 30 degree, 45 degree and 60 degree and the characteristics were observed for 1 minute and 2 minutes at an ion beam irradiation intensity of 600 to 3,000 eV for each angle. The Alignment of the liquid crystals were observed using a polarized microscope after preparing antiparallel specimens. The pretilt angle of the liquid crystal using the crystal rotation method was measured, and the applicability to actual products was evaluated. Experimental results showed that uniformly aligned liquid crystals could be obtained in samples irradiated at 1 and 2 minutes with an ion beam intensity of 1200 eV or higher when irradiated with 30 degree and 45 degree tilted ion beams. And, at 60 tilted degree, It shows that uniformly aligned liquid crystals could be obtained in samples irradiated at 1 and 2 minutes with an ion beam intensity of 2400 eV or higher. The pretilt angle of the liquid crystal showed the best characteristics when irradiated with ion beam inclined at 45 degrees, and it was confirmed that the pretilt angle was 0.2 to 1.3 degrees, which is usable for horizontally oriented LCD.
        4,000원
        9.
        2019.01 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Cr-Al alloys are attracting attention as oxidation resistant coating materials for high temperature metallic materials due to their excellent high temperature stability. However, the mechanical properties and oxidation resistance of Cr-Al alloys can be further enhanced, and such attempts are made in this study. To improve the properties of Cr-Al alloys, Si is added up to 5 wt%. Casting specimens with different amounts of Si content are prepared by a vacuum arc remelting method and isothermally heated under steam conditions at 1,100oC for 1 hour. The as-cast microstructure of low Si alloys is mainly composed of only a Cr phase, while Al8Cr5 and Cr3Si phases are also observed in the 5% Si alloy. In the high Si alloy, only Cr and Cr3Si phases remain after the isothermal heating at 1,100oC. It is found that Si additions slightly decrease the oxidation resistance of the Cr-Al alloy. However, the microhardness of the Cr-Al alloy is observed to increase with an increasing Si content.
        3,000원
        10.
        2018.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        목적: 조명에 따른 동공 크기가 고위수차에 미치는 영향을 알아보고자 하였다. 방법: 안질환이나 전신질환이 없고, 기타 관련 수술 경험이 없는 평균연령 22.5±1.04세의 35명을 대상 자로 선정하여 수차를 측정하였다. i.Profiler plus 기기의 특성상 명소시 상태에서 설정된 동공 크기 ʻ3 mmʼ 를 명소시 유사 환경, 반암실 상태에서 설정된 동공 크기 ʻmaximumʼ을 박명시 유사 환경 상태로 가정하였다. 동공 크기와 등가디포커스와 등가착란원의 상관 분석을 실시하였다. 결과: 대상자의 동공 크기를 3 mm, maximum으로 나뉘어 고위수차를 측정하였을 때, RMS는 0.30±0.13 ㎛ 및 0.38±0.15 ㎛로 나타났다. 총 고위수차의 등가디포커스가 동공 크기 3mm에서 0.28±0.14 D와 maximum에서 0.41±0.16 D 이었고, 유의한 차이를 보였다(p=0.000). 동공 크기 3 mm와 maximum 에서 구면수차, 코마수차, 트레포일 수차의 등가디포커스의 차이는 각각 0.07 D, 0.04 D, 0.02 D 이었고, 구면수차(p=0.000) 및 코마수차(p=0.000)에서 유의한 차이가 있었다. 등가디포커스와 등가착란원 사이에서 유의한 양의 상관관계가 존재하였다(총 고위수차(R2=0.7045, p<0.01), 구면수차(R2=0.9376, p<0.01), 코마 수차(R2=0.8429, p<0.01), 트레포일수차(R2=0.7824, p<0.01)). 결론: 수차 측정 결과를 등가디포커스로 나타내어 교정이 필요한 정도를 디옵터로 표현할 수 있었다. 고 위수차의 교정이 고려되지 않았을 경우, 교정시력에 변화가 있을 것으로 예측되어 고위수차의 시각적 불편함에 대한 연구가 중요하다고 사료된다.
        4,500원
        11.
        2016.10 구독 인증기관·개인회원 무료
        The glycoprotein hormone family consists of luteinizing hormone (LH), follicle stimulating hormone (FSH) and thyroid stimulating hormone, which are secreted by the pituitary gland in all mammalian species, and choriogonadotropin (CG), which is secreted by the placenta in primates and equids. The hormones are composed of a common α subunit and a hormone specific β subunit which are non-covalently associated. Recent advances in biotechnology, particularly in the production of recombinant proteins, have provided opportunities to produce sufficient quantities of recombinant fish GTHs using various expression hosts. Japanese eel Anguilla japonica is one of the most important fish species being aquacultured in Japan but is hampered from the fact that this species does not reproduce in captivity. Artificial induction of gonadal maturation has been successful by administration of pituitary extracts or human chorionic gonadotropin, but the understanding the regulatory mechanism of gonadal development moderated by follicle stimulating hormone (FSH) and luteinizing hormone (LH) remains elusive due to lack of suitable amounts of eel gonadotropins (GTHs). In the present study, we produced tethered rec-eel LH and deglycosylated mutants (56, 79 and 56-79 of α subunit; 10 of β-subunit) of Asn-linked oligosaccharides in CHO suspension cells. Luteinizing hormone acts through binding to its specific receptor. Binding of ligand to the receptor activates the adenosine 3',5'-cyclic monophosphate (cAMP) pathway (McFarland et al., 1989; Ji and Ji, 1991a; Rose, 1998) and the inositol 1 phosphate (IP1) secondary messenger systems. After stimulation of eelLH/CG receptor transfected CHO cells with rec-LH wild type (wt) and mutant hormones as a ligand, production of cAMP and IP-1 were evaluated (Cisbio). cAMP IC-50 values by rec-eelLH wt; αΔ56; αΔ79; αΔ56_79 and βΔ10 were 606.2; 374.9; 100.3; 14.2 and 210.9 ng/ml, respectively. IP-1 IC-50 values by rec-eelLH wt; αΔ56; αΔ79; αΔ56.79 and βΔ10 were 28.3; 16.04; 4.3; 2.1 and 3.6ng/ml, respectively too. As seen in both of the second messenger production, general stimulatory pattern is analogous. cAMP and IP-1 stimulation by wild type and αΔ56, as well as αΔ79 and βΔ10 were approximate, but the stimulating effect of double mutant (αΔ56_ 79) was drastically higher. According to the data, deglycosylated eelLH may bind to the receptor with high affinity and cAMP production is gradually increased. Furthermore, receptor activation by tethered rec-eel mutant ligands (FreeStyle CHO-MAX Expression System) will be evaluated with β arrestin recruitment and GPCR internalization for N-linked oligosaccharides’ biological role in activation of eelLH/CGR.
        12.
        2015.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 탐방객 인식에 기반한 보다 분석적인 접근의 국립공원 시설관리방안을 제시하고자 하였다. 덕유산국립공 원과 태안해안국립공원 탐방객 대상 총 214매를 유효표본으로 기술분석과 중요도-성취도 분석 실시 결과 태안해안국립 공원은 지속적 관리노력 필요 항목이 4개, 저우선순위 항목이 3개, 과잉 노력 지양항목이 2개로 평가되었다. 덕유산국립 공원은 지속적 관리노력 필요 항목이 3개, 우선시정 필요 항목 1개, 저우선순위 항목이 4개로 나타났다. 관리상태에 대한 전반적인 만족도는 2개소 모두 긍정적이며 국립공원 이용에 대한 종합적인 만족도 또한 3점 이상으로 나타났으나 덕유산국립공원이 태안해안국립공원에 비해 두 분야 모두 더 높게 평가되었다. 태안해안국립공원은 세부 관리속성 모두에서 관리상의 미진한 점이 나타났다. 이는 산악형 국립공원과는 상이한 해상해안형 국립공원의 탐방특성에 기인 한 결과로 보이며 국립공원 유형별로 상이한 이용특성의 분석에 기초한 시설관리가 탐방만족 제고를 위한 필수요건으 로 판단된다.
        4,000원
        13.
        2015.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        경남 창원과 진주의 농약 무살포 및 유기농 단감원에서 단감 잎을 가해하는 해충을 조사한 결과 국내에서 단감 해충으로 기록되지 않은 3종 을 채집 동정하였다. 동정된 종은 가을뒷노랑밤나방, 푸른빛집명나방, 감잎가는나방(신칭)이었다. 이들의 채집기록, 형태, 기주와 간단한 생태를 조사하여 보고한다.
        3,000원
        14.
        2013.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        약용식물 중 잔류농약의 안전성을 평가하고자 2012년 전국 9개 도시에서 유통되고 있는 인삼과 도라지에 대하여 전체 112점의 시료를 수거하여 잔류농약을 분석하였다. 122 종의 농약에 대해 GC-ECD, GC-NPD 및 HPLC-UVD를 이용한 다종농약 다성분 분석법으로 잔류농약을 분석하였고, 분석 결과 12점의 시료에서 7종의 농약이 검출되어 10.7% 검출률을 보였다. 농약 성분별 검출 빈도는 procymidone, kresoxim-methyl, endosulfan, cypermethrin, tralomethrin, tetraconazole, chlorfluazuron 순이었다. 농약 이 검출된 시료 중 잔류허용기준을 초과한 시료는 2점으 로 1.8% 검출률을 보였으며, 도라지 1점에서 tetraconazole, 인삼 1점에서 cypermethrin이 검출되었다. 해당 작물에 대한 잔류허용기준이 설정되어 있지 않거나 품목고시 되어 있지 않은 시료는 10점에서 5종의 농약이 검출되어 8.9% 검출률을 보였다. 본 연구에서 검출된 농약이 해당 약용 식물의 섭취로 인체에 유입될 일일섭취허용량 대비 일일 섭취추정량은 최저 0.006%에서 최고 0.333%로 낮은 %ADI 값을 보여 인체 위해도는 낮은 것으로 판단되었다.
        4,000원
        15.
        2018.06 KCI 등재 서비스 종료(열람 제한)
        The large extracellular domain of glycoprotein hormone receptors is a unique feature within the G protein-coupled receptors (GPCRs) family. After interaction with the hormone, the receptor becomes coupled to Gs, which, in turn stimulates adenylyl cyclase and the production of cAMP. Potential phosphorylation sites exist in the C-terminal region of GPCRs. The experiments described herein represent attempts to determine the functions of the eel follicle-stimulating hormone receptor (eelFSHR). We constructed a mutant of eelFSHR, in which the C-terminal cytoplasmic tail was truncated at residue 614 (eelFSHR-t614). The eelFSHR-t614 lacked all potential phosphorylation sites present in the C-terminal region of eelFSHR. In order to obtain the eelFSHR ligand, we produced recombinant follicle-stimulating hormone (rec-eelFSHβ/α) in the CHO-suspension cells. The expression level was 2-3 times higher than that of the transient expression of eelFSH in attached CHO-K1 cells. The molecular weight of the rec-eelFSHβ/α protein was identified to be approximately 34 kDa. The cells expressing eelFSHR-t614 showed an increase in agonist-induced cAMP responsiveness. The maximal cAMP responses of cells expressing eelFSHR-t614 were lower than those of cells expressing eelFSHR-wild type (eelFSHR-WT). The EC50 following C-terminal deletion in CHO-K1 cells was approximately 60.4% of that of eelFSHR-WT. The maximal response in eelFSHR-t614 cells was also drastically lower than that of eelFSHR-WT. We also found similar results in PathHunter Parental cells expressing β-arrestin. Thus, these data provide evidence that the truncation of the C-terminal cytoplasmic tail phosphorylation sites in the eelFSHR greatly decreased cAMP responsiveness and maximal response in both CHO-K1 cells and Path-Hunter Parental cells expressing β-arrestin.