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        검색결과 102

        41.
        2012.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Kim Ha-soo, Ju Hyang-a, Son Hyun-jung, Kong Nah-yung. 2012. Geographic Information System(GIS) and sociolinguistic factors- study on the information of Korean language education. The sociolinguistic Journal of Korean 20(2). pp. 185-211. In sociolinguistic research, it has been found that linguistic phenomena are influenced more by extralinguistic factors than intralinguistic ones. In particular, issues such as language policy, language contact, langage extinction and language variation are strongly affected by geographical characteristics of the region where a language is being used and taught. In order to analyze linguistic phenomena and geographical characteristics synthetically, we introduce linguistic typological methods using Geographic Information System (GIS), an automated system for the capture, storage, retrieval, analysis and display of spacial data. Using GIS, we present some maps of the geographical distribution of foreigners living in Korea and the educational institutions of Korean language for foreigners in order to discuss the regional conditions for Korean language education in these areas. We also examine married immigrant women's accessibility to multi-cultural support centers with GIS.
        6,600원
        42.
        2012.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, we mainly focus on the study of densification of gas-atomized Cu-50 wt.%In-13 wt.%Ga alloy powder without occurrence of crack during the forming process. Cu-50 wt.%In-13 wt.%Ga alloy powder was consolidated by sintering and rolling processes in order to obtain high density. The phase and microstructure of formed materials were examined by X-ray diffraction (XRD), scanning electron microscopy (SEM) and optical microscopy (OM), respectively. Warm rolling using copper can result in the improvement of density. The specimen obtained with 80% of rolling reduction ratio at using cooper can have the highest density of .
        4,000원
        43.
        2012.06 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        This study evaluated the enhancement of microstructural and mechanical properties of a cross rolled Ni-10Cr alloy, comparing with conventionally rolled material. Cold rolling was carried out to 90% thickness reduction and the specimens were subsequently annealed at 700˚C for 30 min to obtain a fully recrystallized microstructure. Cross roll rolling was carried out at a tilted roll mill condition of 5˚ from the transverse direction in the RD-TD plane. In order to observe the deformed microstructures of the cold rolled materials, transmission electron microscopy was employed. For annealed materials after rolling, in order to investigate the grain boundary characteristic distributions, an electron back-scattering diffraction technique was applied. Application of cold rolling to the Ni-10Cr alloy contributed to notable grain refinement, and consequently the average grain size was refined from 135 μm in the initial material to 9.4 and 4.2 μm in conventionally rolled and cross rolled materials, respectively, thus showing more significantly refined grains in the cross rolled material. This refined grain size led to enhanced mechanical properties such as yield and tensile strengths, with slightly higher values in the cross rolled material. Furthermore, the<111>//ND texture in the CRR material was better developed compared to that of the CR material, which contributed to enhanced mechanical properties and formability.
        4,000원
        44.
        2011.10 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        We carried out this study to evaluate the grain refining in and the mechanical properties of alloys that undergo severe plastic deformation (SPD). Conventional rolling (CR) and cross-roll rolling (CRR) as SPD methods were used with Ni-20Cr alloy as the experimental material. The materials were cold rolled to a thickness reduction of 90% and subsequently annealed at 700˚C for 30 min to obtain a fully recrystallized microstructure. For the annealed materials after the cold rolling, electron back-scattered diffraction (EBSD) analysis was carried out to investigate the grain boundary characteristic distributions (GBCDs). The CRR process was more effective when used to develop the grain refinement relative to the CR process; as a result, the grain size was refined from 70μm in the initial material to 4.2μm (CR) and 2.4μm (CRR). These grain refinements have a direct effect on improving the mechanical properties; in this case, the microhardness, yield and tensile strength showed significant increases compared to the initial material. In particular, the CRR-processed material showed more effective values relative to the CR-processed materials. The different texture distributions in the CR (001//ND) and CRR (111//ND) were likely the cause of the increase in the mechanical properties. These findings suggest that CRR can result in materials with a smaller grain size, improved texture development and improved mechanical properties after recrystallization by a subsequent annealing process.
        4,000원
        45.
        2011.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        국내 고속도로의 60% 이상이 시멘트 콘크리트 포장으로 건설되었으며, 그 중 공용년수가 20년이 넘어선 구간이 절반 이상에 달하고 있다. 노후화된 시멘트 콘크리트 포장의 보수 보강은 국내의 교통여건상 우회도로가 준비되기 어렵기 때문에 조기 교통개방이 요구되며 현재까지는 주로 아스팔트 덧씌우기가 사용되고 있다. 반면에 아스팔트 덧씌우기 포장은 조기 파손으로 인해 많은 유지보수비용이 지출됨과 동시에 도로사용자의 불편을 초래하고 있다. 최근 들어 노후화 된 시멘트 콘크리트 포장의 효율적인 보강공법으로 접착식 콘크리트 덧씌우기 공법에 대해서 적용을 시도하고 있다. 따라서 아스팔트 덧씌우기 포장과 접착식 콘크리트 덧씌우기 포장의 합리적인 선택에 대한 비교 분석을 위해 포장의 연도별 파손상태에 대한 다양한 data가 필요하다. 하지만, 국내에서는 아스팔트 덧씌우기 포장과 접착식 콘크리트 덧씌우기 포장의 공용 중 파손상태에 대한 자료가 체계적으로 구축되어있지 않다. 본 연구에서는 아스팔트 덧씌우기와 접착식 콘크리트 덧씌우기 공법이 적용된 구간의 파손에 대해 충분한 자료를 구축하고 있는 미국의 LTPP Data를 이용하여, 공용성에 대해서 평가하였다. 단, 아스팔트 덧씌우기와 접착식 콘크리트 덧씌우기 공법은 파손형태가 서로 상이함으로써, 상대적인 비교를 위해 각각의 구간에 대해 포장상태지수(PCI, Pavement Condition Index)를 Database화 하였으며, 아스팔트 덧씌우기 구간과 접착식 콘크리트 덧씌우기 구간의 수명에 대해서 비교 분석을 수행하였다.
        4,000원
        46.
        2011.05 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        The present study was carried out to evaluate the microstructural and mechanical properties of cross-roll rolled pure copper sheets, and the results were compared with those obtained for conventionally rolled sheets. For this work, pure copper (99.99 mass%) sheets with thickness of 5 mm were prepared as the starting material. The sheets were cold rolled to 90% thickness reduction and subsequently annealed at 400˚C for 30 min. Also, to analyze the grain boundary character distributions (GBCDs) on the materials, the electron back-scattered diffraction (EBSD) technique was introduced. The resulting cold-rolled and annealed sheets had considerably finer grains than the initial sheets with an average size of 100 μM. In particular, the average grain size became smaller by cross-roll rolling (6.5 μM) than by conventional rolling (9.8 μM). These grain refinements directly led to enhanced mechanical properties such as Vickers micro-hardness and tensile strength, and thus the values showed greater increases upon cross-roll rolling process than after conventional rolling. Furthermore, the texture development of<112>//ND in the cross-roll rolling processed material provided greater enhancement of mechanical properties relative to the case of the conventional rolling processed material. In the present study, we systematically discuss the enhancement of mechanical properties in terms of grain refinement and texture distribution developed by the different rolling processes.
        4,000원
        47.
        2011.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        국내 고속도로의 60% 이상이 시멘트 콘크리트 포장으로 건설되었으며, 그 중 공용년수가 20년이 넘어선 구간이 절반 이상에 달하고 있다. 노후화된 시멘트 콘크리트 포장의 보수 보강은 국내의 도로 교통여건상 우회도로가 준비되기 어렵기 때문에 조기 교통개방이 요구되며 현재까지는 주로 아스팔트 덧씌우기가 사용되고 있다. 반면에 아스팔트 포장은 조기파손과 잦은 보수 때문에 보수 보강에 대한 비용이 크다. 현 시점에서 아스팔트 덧씌우기가 국내에서 가장 많이 사용되고 있는 현실을 감안할 때, 아스팔트 덧씌우기의 수명에 미치는 영향인자가 무엇인지 검토할 필요가 있다. 따라서 아스팔트 덧씌우기 공법의 성능에 영향을 미치는 인자에 대해 조사할 필요가 있으나, 국내의 경우 아스팔트 덧씌우기의 공용 중 파손상태에 대한 자료가 체계적으로 구축되어있지 않다. 본 연구에서는 아스팔트 덧씌우기 수명과 영향인자간의 상관성을 비교하기 위해 다양한 파손자료를 구축하고 있는 미국의 LTPP data를 이용하여 노후화 된 시멘트 콘크리트 포장의 아스팔트 덧씌우기에 대해 조기파손을 방지하고, 효율적인 보수 보강을 위해서 아스팔트 덧씌우기 구간의 수명에 미치는 영향인자에 대해서 통계분석을 수행하였다.
        4,800원
        48.
        2010.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Abnormal prions are infectious agents involved in a neuro-degenerative disease, which occurs naturally such as Chronic Wasting Disease (CWD) in deer and elk, Bovine Spongiform Encephalopathy (BSE) in cattle, Scrapie in sheep and goats and Creutzfeldt-Jakob Disease (CJD) in humans. The cellular prion protein of the elk consists of 233 amino acids (residues 25-257), which represents an autonomous folding unit with three α-helices and two-stranded anti-parallel β-sheets. Here, we demonstrated elk-recPrP (Elk recombinant prion protein) which can be obtained as follows; (1) Cloning of elk PrP gene, (2) Expression of a histidine-tagged full-length elk PrP by induction with IPTG in E. coli and (3) Purification by affinity chromatography using Ni-NTA agarose resin. In Western blot and ELISA analysis, elk-recPrP showed specific activity against anti-PrP monoclonal antibody. Thus, our elk-recPrP would be a useful tool for the understanding of basic structure and mechanism studies of PrPSC formation.
        4,000원
        50.
        2009.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        A composite of rapidly solidified Al-6061 alloy powder with graphite particle reinforcements was prepared by ball milling and subsequent hot extrusion. The microstructure and mechanical properties of these composites were investigated as a function of milling time. With increasing milling time, the gas atomized initially and spherical powders became elongated with a maximum aspect ratio after milling for 30 h. Then, refinement and spheroidization were achieved by further milling to 70 h with a homogeneous and fine dispersion of graphite particles forming between the matrix alloy layers. The best compression and wear properties were obtained in the powder milled for 70 h, associated with the increased fine and homogeneous distribution of graphite particles in the aluminum alloy matrix.
        4,000원
        51.
        2008.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The hydrosilylation is an addition reaction of Si-H bond to unsaturated double bonds, which provides a convenient mechanism to synthesize poly(dimethylsiloxane-co-methylsiloxane)copolymer having siloxy units in polymer backbone. In this study, Poly(dimethylsiloxane-co-methylsiloxane) copolymer was synthesized through the polymerization reaction of cyclopentasiloxane with poly(methyl-hydrogen) siloxane. Silicone-hydrogen functional group of the poly(dimethylsiloxane-co-methylsiloxane) copolymer was substituted to the alkyl groups by hydrosilylation. And their structure was analyzed with FT-IR, H-NMR and GPC instruments, respectively. Surface tension of the synthetic compounds is increased from 22dyne/cm to 25dyne/cm according to increase additional EO moles. The cmc which was evaluated by surface tension was ranged 10-5 to 10-4mol/L and it was decreased according to increase of dimethyl siloxyl content. HLB number of these surfactants was evaluated 9.5 to 11.5 range. These silicone surfactants is applied to self-emulsifier defoamer and personal care products as surface tension depressant, emulsifier, foam control agent.
        4,000원
        52.
        2008.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        4,800원
        53.
        2007.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The human ELAV(embryonic lethal abnormal vision)-like protein HuR stabilizes a certain group of cellul ar mHNAs that contain AU- rich elements in their 3’ - untranslated region , To test the significance of HuR in carcinogenesis of head and neck squamous cell carcinomas(HNSCCs), we have investigated HuH expression from 32 benign epithelial lesions , 14 prema lignant epitheli al lesions and 80 HNSCCs, There were two different staining patterns of HuR in HNSCCs : nuclear expression was seen in 78 7% (63 of 80) 01' cases; and an additional cyto plasmic expression was seen in 28, 7%(23 of 80) 01 cases, Nuclear expression of HuR was s ignificantly increased in premalignant lesions and HNSCCs, whereas increased cytoplasπli c expression of HuR was only observed in HNSCCs Cytoplasmic HuR expression was significantly increased in pa tients of HNSCC younger than 60 yea rs , Al though there was no significant correlation between a natomic s ites of HNSCCs and HuR express ion , cyto plasmic HuR expression was highly increased in HNSCCs of larynx, There was no significant co rrela tion between HuR expression and other clinicopathological parameters such as histological type‘ tumor s ize‘ 0 1' n odal s tatus , ln conclusion, this study s uggests that overexpression of HuR in HNSCCs may be part of a regula tory pathway tha t co ntro ls the mHNA stability 0 1' several important targets in carcinogenesis of HNSCCs
        4,000원
        54.
        2007.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        최근의 환경정책은 신설되는 도로에 대하여 비점오염저감시설 설치의무화를 요구하고 있다. 또한 도로건설시 및 유지관리시에는 발생가능한 비점오염물질을 예측하고 이를 저감할 수 있는 방향으로 노선의 계획 및 설계와 더불어 다양한 비점저감방안을 수립할 것을 요구하고 있다. 비점오염원 및 비점오염물질을 관리하기 위해서는 우선 유역의 토지이용도를 분석하여 강우시 배출되는 오염물질의 종류와 양을 산정해야 한다. 특히 도로의 경우, 발생되는 비점오염물질의 원단위가 별도로 존재하지 않고 대지항목의 오염발생원단위를 사용하고 있기에 적용함에 있어서 많은 어려움을 겪고 있는 실정이다. 따라서 본 연구는 포장지역 중 고속도로 영업소를 대상으로 강우시 유출되는 강우유출수의 특성을 파악하여, 이러한 토지이용에서의 비점오염물질 유출특성과 부하량을 산정하고자 한다. 영업소 토지이용의 경우 많은 차량이 속도를 급격히 줄이는 토지이용지역으로 브레이크 패드, 각종 오일 및 엔진파트 등으로부터 많은 양의 오염물질이 축적되고, 포장률이 높아 강우시 다량의 오염물질이 유출되는 지역이다. 본 연구를 통해서 영업소 토지이용지역에서의 초기강우현상을 수리수문 및 농도곡선을 통해 확인할 수 있었다. 또한 EMC로부터 단위면적당 부하량과 강우지속시간당 부하량을 산정하였으며, 이러한 값은 영업소 유지관리시 인근수계에의 환경적인 영향을 해석하기 위한 기초자료로 활용될 수 있다. 강우지속시간당 유출되는 평균부하량은 TSS의 경우 533.7mg/m2-hr, COD 396.2mg/m2-hr, TN 17.0mg/m2-hr, TP 4.8mg/m2-hr로 산정되었다.
        4,000원
        58.
        2007.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Ameloblastic carcinoma is an ameloblastoma wi th histological malignant transformation with 01' without metastatic di sease_ We report an ameloblastic carcinoma ex ameloblastoma of right mandibular body in 7 -year-old girl with a heterogeneo us hi stologic components_ The tumor s howed so lid s heets composed of atypical kerati nized squamous cells. small ovoid cell s. and s pind le cells in addi tion to a bit of beni gn ameloblastoma component_ Immunohis tochemically, the squ amous cells were strongly cytokemtin posi ti ve/vimentin negati ve and the small ovoid and spindle ce lls were weakJy cytokeratin positi ve/v imentin pos it ive_
        3,000원
        59.
        2007.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Human saliva conta ins a la rge number of proteins and peptides whose composition may alter as a conseq uence of disease. '1'0 date‘ however. the proteins and peptides that routinely populate t his oral fluid are largely unknown, '1'0 provid e a ca ta logue 이, sali va protei ns. we have surveyed the unstimulated human whole saliva by using shotgun proteomics. F'or the shotgun a pproach‘ whole sali va proteins were digested into peptides with ChemDigestD and the res ulting pe ptide fragments were sepa rated by RP- HPLC, followed by each fraction was tryptic di gestion ChemDiges tD- Trypsin diges ted pe pt ides were analyzed by tandem mass spectrometry (MS!MS) using a nano-LC equi pped quadru po le-time of fli ght rnass spect rometer, and the obtained spectra were searched against human protein sequence da tabase us ing MASCOT Shotgun proteomics a llowed a total of 291 human proteins to be confidently assigned. The largest gro u p (17 , 2%) of the identifi ed proteins sorted into functional categories was included in the s ignal transducti on function except for the hypothet ical or unknown functio n, This work provides a valuable starting point for the ana lys is of human sa l i va ry protei ns a nd theil‘ biological functions and candidates from human whole saliva that may prove to be of diagn ost ic and t herapeutic s ignif‘ Ica nce
        4,300원
        60.
        2007.02 구독 인증기관 무료, 개인회원 유료
        Oxidation characteristics of benzene as a VOC was investigated using a fixed bed reactor system over copper base catalysts. The copper base catalysts were made by using copper nitrate reagent and various support materials such as γ-Al2O3, TiO2, and zeolite. The parametric tests were conducted at the reaction temperature range of 200~500℃, benzene concentration of 1,000~2,000 ppm, and space velocity range of 5,000~20,000 hr-1. The property analyses such as BET, SEM, XRD and the conversions of catalytic oxidation of VOC were examined. XRD analysis on copper catalysts showed CuO crystal forms and the peak intensity of CuO increased as the impregnation weight of copper grew. The experimental results showed that the conversion was increased with decreasing space velocity. It was also found that Cu/γ-Al2O3+TiO2 catalyst showed the highest activity for the oxidation of benzene and 15% metal loading was the optimum impregnation level.
        4,800원
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