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습식법을 이용하여 전구체 Gd₂O₃나노튜브를 제조한 후, 공기중에서의 열처리를 통하여 Eu^(3+)가 첨가된 Gd₂O₃ 나노튜브를제조하였다. 제조된 시료의 구조 및 형상은 XRD, 라만분광 및 FE-SEM을이용하여 분석하였으며, 광활성제로 첨가된 Eu^(3+)의 광학적 특성은여기 및 발광스펙트럼 등의 측정을 통하여 분석하였다. 라만스펙트럼의분석을 통하여 기존에 보고되지 않은 새로운 피크가 존재한다는 사실을확인하였으며, 전하이동밴드에 의한 여기효율은 Gd₂O₃ 나노튜브에첨가된 Eu^(3+)의 농도가 7%일 때에 가장 좋았다. 254 nm의여기파장으로 시료를 여기하여 Eu^(3+)에 기인한 발광스펙트럼을측정한 결과, 전형적인 Eu^(3+)에 기인한 발광특성를 보여주고 있으며,모든 천이들 가운데에 ^5(D_0)-^7(F_2)천이에 해당하는 613 nm 에서발광세기가 가장 강하였다. 또한, Gd₂O₃의 용융온도가 2,330℃ 매우 높은데도 불구하고, 열처리 온도가 1,100℃이상에서는 나노튜브가 용융되기 시작한다는 사실도 확인하였다. Eu^(3+) doped Gd₂O₃nanotubes were prepared by employing a simple wet-chemical route through heat treatment in air by using Gd(OH)3 as the precursor. Their structural and morphological features were analyzed by using X-ray diffraction (XRD), Raman spectroscopy and field-emission scanning electron microscopy (FE-SEM). The photoluminescent properties of Eu^(3+) doped Gd₂O₃ nanotubes were studied by measuring their excitation and emission spectra. New Raman peaks, not previously reported were found at 250 cm^(-1) through an analysis of Raman spectra. We also noticed a strong charge transfer band in the excitation spectrum of Eu^(3+) doped Gd₂O₃ nanotubes, and it quenched at 7 mol% of Eu^(3+). Using 254 nm as the excitation wavelength, we recorded the emission spectr of Eu^(3+) doped Gd₂O₃ nanotubes, and it exhibited all the characteristic transitions of the Eu^(3+) dopant ion, and among all, the ^5(D_0)-^7(F_2) transition at 614 nm was most intense. Even though bulk Gd₂O₃ has a high melting temperature of 2,330℃, the studied nanotube samples began to melt at 1,100℃.
Catalyst free Gd2O3:Eu3+sphere phosphors were prepared by using hydrolysis method, and their structural & optical properties were investigated. Their structural and morphological features were analyzed by using X-ray diffraction (XRD) and Field-emission scanning electron microscopy (FESEM). The photoluminescence properties of the Eu3+-doped Gd2O3 spheres were studied by using a spectrophotometer to measure their excitation and emission spectra. The X-ray diffraction profiles showed that all peaks could be attributed to the cubic phase which is in good agreement with the standard JCPDS (86-2477) card. FE-SEM indicated that the morphology of the phosphor sphere had with an outer diameter of about 500 nm. We also observed a strong charge transfer band in the excitation spectrum of Eu3+-doped Gd2O3-sphere phosphors, which quenched at Eu3+ concentrations over 7 mol%. We also recorded the emission spectra of Eu3+-doped Gd2O3-sphere phosphors at excitation wavelength of 254 nm. The results showed all the characteristic transitions of the Eu3+ dopant ion, along with a high-intensity peak at 613 nm which corresponded to the 5D0-7F2 transition. 가수분해법을 응용하여 별다른 촉매없이 Gd2O3:Eu3+구형형광체를 제조하고 결정구조와 광학적 특성에 대하여 연구하였다. 제조된시료의 결정구조 및 형상은 XRD, FE-SEM을 이용하여 분석하였으며,광활성제로 첨가된 Eu3+의 광학적 특성은 여기 및 발광스펙트럼등의 측정을 통하여 분석하였다. XRD 분석을 통하여 Gd2O3결정에대한 표준 JCPDS와 제조된 시료에 대한 주요 피크들이 잘 일치함을관찰할 수 있었고, 이들로부터 Eu3+가 첨가된 Gd2O3:Eu3+ 시료는입방 구조임을 확인하였다. FE-SEM을 이용해 측정한 결과, 직경이 약 500nm 정도인 구형모양이었다. 전하이동밴드에 의한 여기효율은 구형의Gd2O3 모체에 첨가된 Eu3+의 농도가 7%일 때에 가장 좋았다. 또한 254 nm의 여기파장으로 시료를 여기하여 Eu3+에 기인한발광스펙트럼을 측정한 결과, 전형적인 Eu3+에 기인한 발광특성을보였으며, 모든 천이들 가운데에 5D0-7F2 천이에 해당하는613 nm 에서 발광세기가 가장 강하였다.
Objective : Because of the complex anatomical association among vascular,dural, and bony structures, paraclinoid internal carotid artery (ICA)aneurysms remain a major challenge for vascular neurosurgeons. Westudied the clinical outcomes of 61 paraclinoid ICA aneurysms after microsurgicalclipping in comparison with endovascular coiling. Materials and Methods : Between January 2008 and December 2012, wetreated 61 paraclinoid ICA aneurysms created by surgical clipping or endovascularcoiling. Preoperative neurologic status and postoperative outcomewere evaluated using the Glasgow coma scale (GCS) and themodified Rankin scale (mRS). Postoperative hydrocephalus and vasospasmwere reviewed using the patients' medical charts. Results : Most patients were in good clinical condition before the operationsand had good treatment outcomes. Clinical vasospasm was observedafter the operation in five patients, and hydrocephalus occurred insix patients. No statistically significant difference regarding aneurysm size,sex, GCS score, H-H grade, and mRS was observed between the surgicalclipping group and the endovascular coiling group. In addition, the treatmentresults and complications did not show statistically significant differencein either group. Conclusion : Surgical occlusion of paraclinoid ICA aneurysms is difficult;however, no significant differences were observed in the treatment resultsor complications when compared with coil embolization. In particular, useof an adequate surgical technique may lead to better outcomes thanthose for coil embolization in the treatment of large and/or wide-neckparaclinoid ICA aneurysms.
Titanium/aluminum/stainless steel(Ti/Al/STS) clad materials have received much attention due to their high specific strength and corrosion-resisting properties. However, it is difficult to fabricate these materials, because titanium oxide is easily formed on the titanium surface during heat treatment. The aim of the present study is to derive optimized cladding conditions and thereupon obtain the stable quality of Ti/Al/STS clad materials. Ti sheets were prepared with and without pre-heat treatment and Ti/Al/STS clad materials were then fabricated by cold rolling and a post-heat treatment process. Microstructure of the Ti/ Al and STS/Al interfaces was observed using a Scanning Electron Microscope(SEM) and an Energy Dispersed X-ray Analyser(EDX) in order to investigate the effects of Ti pre-heat treatment on the bond properties of Ti/ Al/STS clad materials. Diffusion bonding was observed at both the Ti/Al and STS/Al interfaces. The bonding force of the clad material with non-heat treated Ti was higher than that with pre-heat treated Ti before the cladding process. The bonding force decreased rapidly beyond 400℃, because the formed Ti oxide inhibited the joining process between Ti and Al. Bonding forces of STS/Al were lower than those of Ti/Al, because brittle Fe3Al, Al3Fe intermetallic compounds were formed at the interface of STS/Al during the cladding process. In addition, delamination of the clad material with pre-heat treated Ti was observed at the Ti/Al interface after a cupping test.
In order to meet increasingly complex and rigorous technical specifications, extensive effort has been devoted to fabricate clad materials with multi-layered metal plates. In this study, novel stainless steel/aluminum/copper (STS/Al/Cu) three-ply clad materials were fabricated by a hot rolling process for cookware applications. The effect of the testing temperature on the mechanical properties of the clad materials and on each component metal was investigated during the tensile tests. The interface properties of the clad materials were also examined by optical microscopy (OM) and an electron probe micro-analyzer (EPMA). The best mechanical and interfacial properties for a warm working process were found in a sample annealed at a temperature of 300℃. For the sample annealed at 400℃, the results of the tensile test indicated that interface delamination occurred only in the region of the Al/Cu interfaces. This was due to the formation of the thick and brittle intermetallic compound of Al2Cu in the Al/Cu interface. In contrast, no interface delamination was observed in the STS/Al interface, most likely due to its strong bond strength.
목적 : 자궁경부상피내종양 및 침윤성암종을 대상으로 우리나라에 많은 다양한 인유두종바이러스 감염을 DNA chip을 이용하여 검사하고 또한 p53 코돈 72의 유전자다형성을 대립유전자 특이중합효소연쇄반응 (allele specific polymerase chain reaction) 기법으로 검사하여 우리나라 여성에서의 p53 코돈 72 유전자 다형성과 인유두종바이러스 감염과의 관계를 연구하고자 하였다. 연구 방법 : 순천향대학교 천안병원 산부인과에서 2000년 3월부터 2003년 3월까지 자궁경부종양 및 침윤 암으로 진단된 자궁경부 생검 혹은 자궁적출 조직 125예를 대상으로 하였다. 이들의 조직에서 DNA를 추출하고 이어 DNA chip을 이용하여 인유두종바이러스 유전형을 검사하였다. 결과 : 총 125예의 평균 연령은 53.8세 이었고, 이들중 low grade squamous intraepithelial lesion (LSIL) 30예, high grade squamous intraepithelial lesion (HSIL) 50예, 및 침윤성암이 45예 이었다. 1) 한국인 여성에서 자궁경부 종양 발생과 관련이 있는 인유두종바이러스 유전형은 16형(25.6%), 58형(16%), 기타 유전형(10.4%), 52형(10%), 및 18형(4.8%) 순으로 나타났다. 2) 200명의 여성을 대상으로 검사한 p53 코돈 72의 유전자다형성 유전형 빈도는 Arg/Arg, Arg/Pro, 및 Pro/Pro 각각 47%, 43% 및 10% 이었다. 3) 인유두종바이러스 감염과 관련된 자궁경부종양에서 p53 코돈 72의 유전자다형성은 Arg/Arg, Arg/Pro 및 Pro/Pro 각각 55.5%, 38.9% 및 5.5%로 대조군의 47%, 43% 및 10%와 비교하여 통계적 의의가 없었다(p>0.05). 4) 상이한 인유두종바이러스 유전형 간 p53 코돈 72의 유전자다형성은 Arg/Arg, Arg/Pro 및 Pro/Pro 각각 16/18 감염군에서 44.8%, 42.1% 및 13.1% 이었고, 58/52/기타 유전형/33/35/40/44형 군에서는 36.5%, 50% 및 13.5%로 각 형에 따른 대조군의 47%, 43% 및 10%와 비교할 때 상호 특이한 차이가 없었다(p>0.05) 결론 : 이상의 결과를 종합해 보면, 우리나라여성의 자궁경부종양과 관련된 인유두종바이러스 유전형은 16형과 58형으로 서구의 16형과 18형과 비교할 때 상이함을 알 수 있고, 또한 감염된 바이러스 유전형에 따른 종양발생과 p53유전자 코돈 72의 다형성은 바이러스관련 자궁경부종양 발생과 관련이 없었다. Objective : The uterine cervical neoplasia is one of the most frequent gynecologic tumor in Korean women. Though the precise pathogenic mechanisms were not elucidated, human papillomaviruses (HPVs) has been considered as a strong candidate for the cause of uterine cervical neoplasm. Methods : About 100 subtypes of HPV were known, and they were divided into two groups as "high-risk HPVs" and "low-risk HPVs" according to their oncogenic potentialities. It was known that arginine (Arg) residue at codon 72 of p53 tumor suppressor gene could be used as a marker for the risk of cevical epithelial neoplasia associated human appilloma virus infection. But the notions are still controversal. Studies to date have focused mainly on Caucasians despite marked ethnic variations in both the p53 polymorphism and the different genotypes of human papillomavirus associated with cervical neoplasia. In this study, the p53 codon 72 status in 125 Korean women with cervical neoplasia and 200 Korean healthy women was determined. In addition, the different genotypes of human papillomavirus associated with cervical neoplasia was also determined by DNA Chip. Results : The most frequent subtypes of HPV associated with uterine cervical neoplasia in korean women were 16 (25.6%), 58 (16%), other type (10.4%), 52 (10%) and 18 (4.8%) in order of frequency. The polymorphic rate of p53 codon 72 in 200 Korean women was Arg/Ar (47%), Arg/Pro (43%) and Pro/Pro (10%) respectively. The polymorphic rate of p53 codon 72 in HPV associated uterine cervical neoplasia was Arg/Ar (55.5%), Arg/Pro (38.9%) and Pro/Pro (5.50%) respectively, which was not statistically significant compared to the normal control. In 16/18 genotypes associated cervical neoplasia, the polymorphic rate of p53 codon 72 was 44.8% (Arg/Arg), 42.1% (Arg/Pro) and 13.1% (Pro/Pro) respectively, while in 58/52/other type/33/35/40/44 genotypes, it was 36.5% (Arg/Arg), 50% (Ar/Pro), and 13.5%(Pro/Pro) respectively. There was no statistical significance between two groups. Conclusion : Above results showed that the genotypes of HPV associated with uterine cervical neoplasia in Korean women were different from those of Western countries, and there was not significant difference between the polymorphism of p53 codon 72 and genotypes of HPV associated with uterine epithelial neoplasia.