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      • KCI등재

        종 분포 모형을 이용한 구상나무림의 지속 및 쇠퇴에 관한 연구 - 전라남도 광양시 백운산을 중심으로 -

        조선희 ( Seon Hee Cho ),박종영 ( Jong Young Park ),박정호 ( Jeong Ho Park ),이양근 ( Yang Geun Lee ),문이만 ( Lee Man Mun ),강상호 ( Sang Ho Kang ),김광현 ( Gwang Hyun Kim ),윤종국 ( Jong Guk Yun ) 한국산림과학회 2015 한국산림과학회지 Vol.104 No.3

        The present study investigated the habitats of Korean fir trees (Abies koreana E. H. Wilson) on Mt. Baekwun (Baekwun-san), determined the current distribution, quantified the contribution of biological and nonbiological environmental factors affecting the distribution, derived actual and potential habitats, presented a plan for the establishment of protected areas, applied RCP 8.5 climate change scenario to analyze the effects of climate change on the future distribution of Korean fir trees, and predicted future potential habitats. According to the results of the study, 3,325 Korean fir trees (DBH >= 2.5 cm) inhabited Mt. Baekwun, and their distribution area was approximately 150 ha. Populations of Korean fir trees were confirmed to exist at an altitude of 900 m above sea level and were distributed up to 1,200 m. Based on potential distribution, areas appropriate for habitation by Korean fir trees were analyzed to be 450 ha, three times the current distribution area, with a focus on Sang Peak (Sang-bong), Eokbul Peak (Eokbul-bong), Ddari Peak (Ddari-bong), and Dosol Peak (Dosol-bong). The forest stands near Sang Peak, the main peak, were evaluated as those with the most appropriate potential for the habitation of Korean fir trees, and populations of the trees tended to prefer the northern slope rather than the southern slope. When climate change scenario RCP 8.5 was applied and future potential distribution was analyzed, the habitats were expected to decrease in area to 20 ha by 2050, with a focus on Sang Peak, and areas appropriate for habitation were predicted not to exist by 2080. Judging from such results, as global warming accelerates, the habitats of Korean fir trees are clearly expected to move from lowlands to highlands.

      • KCI등재

        알쯔하이머병 환자의 뇌혈류 장애 : Statistical Parametric Mapping을 이용한 Tc-99m ECD SPECT 분석 Statistical Parametric Mapping analysis of Tc-99m ECD SPECT

        양동원,김범생,손영민,박정욱,정용안,손형선,김상윤 대한치매학회 2002 Dementia and Neurocognitive Disorders Vol.1 No.2

        Background and Objectives . Alzheimer's disease (AD) is the most common cause of the dementia Pathologic and functional changes of AD are known to be unevenly distributed in the brain. This study investigates changes of cerebral blood flow (CBF) in patients with AD to determine brain regions with hypoperfusion that reflects progression of disease. Methods. Tc-99m-ECD single photon emission computed tomography (SPECT) was performed to measure regional CBF and statistical parametric mapping (SPM) 99 soft ware was used for the automated and objective approach to analyze SPECT image data. Twenty-five patients with mild to moderate dementia who met NINCDS-ADRDA critena for AD (male 11 female 14) and 17 age-matched normal control subjects were studied. The severity of AD was measured by clinical dementia rating (CDR) scale Results. SPM analysis of SPECT images revealed that CBF in the anterior cingulate gyrus left superior panetal cortex left medial frontal cortex left infenor temporal cortex. right thalamus and left hippocampus was significantly decreased in AD patients compared with normal controls (corrected p<0.05). The reduction of CBF according to CDR was localized in the left hippocampus and infenor temporal cortex right antenor and postenor ciagulate cortex and right superior panetal cortex (uncorrected p<0.01). Conclusions : Our data suggest that the cognitive dysfunction of AD is strongly related with functional abnormality in discrete brain areas 99m-Tc ECD SPECT with SPM analysis could be used as a useful functional imaging tool in AD study.

      • SCOPUSKCI등재
      • KCI등재

        브라켓 부착을 위한 변형된 레이저 부식법

        윤민성,이상민,양병호 대한치과교정학회 2010 대한치과교정학회지 Vol.40 No.2

        전단결합강도를 강화하기 위해 레이저를 이용한 부식과 산을 이용한 부식의 비교 연구가 많이 진행되어왔다. 본 연구에서는 Er,Cr:YSGG laser와 전통적인 산부식법을 혼합한 방법의 전단결합강도의 변화에 대한 평가를 하고자 한다. 교정적인 목적으로 발치된 64개의 건전한 소구치를 이용하여 16개씩 4개의 군으로 나누었다. 첫 번째 군은 37% 인산을 15초 적용시키는 전통적인 부식 방법을 택하였고, 두 번째 군은 물방울레이저로 1.5 W로 10초간 부식시킨 후 전통적인 산부식 방법을 시행하였다. 세 번째 군은 두 번째 군과 같지만 산부식을 먼저 시행한 후 물방울레이저로 부식시켰다. 네 번째 군은 물방울레이저를 이용하여 1.5 W로 15초간 부식시켰다. 이후 전단결합강도의 측정 및 치아 표면의 특징 관찰, 그리고 접착제잔류지수를 평가하였다. 두 번째, 세 번째 군은 첫 번째, 네 번째 군에 대하여 전단결합강도가 높게 측정되었다. 하지만 두 가지 기법의 복합사용 순서를 달리한 두 번째, 세 번째 군 사이에는 통계적으로 유의한 차이가 나지 않았다. 기존 산부식을 이용한 브라켓 접착법보다 산부식과 Er,Cr:YSGG laser를 복합적으로 사용 시, 향상된 전단결합강도를 얻을 수 있다. Objective: Many studies have carried out research on comparisons between laser etching and conventional etching systems to investigate methods of reinforcing shear bond strength. The purposes of this study were to assess the efficiency of bonding with erbium, chromium doped: yttrium-scandium-gallium-garnet (Er,Cr:YSGG) laser etching combined with the conventional etching technique. Methods: Sixty-four sound premolars, extracted for orthodontic purposes, were randomly divided into 4 groups and treated in the following manner. First group, conventional etching of 37% phosphoric acid for 15 seconds (control); second group, 1.5 W laser etching for 10 seconds followed by conventional etching; third group, conventional etching followed by 1.5 W laser etching; fourth group, 1.5 W laser etching for 15 seconds only. We assessed the shear bond strength, the surface characteristics, and the adhesive remnant index scores between all groups. Results: Experimental groups showed higher shear bond strength than the control group. But no statistically significant differences were found between the second and third groups. Adhesive remnant scores were compared with the Kruskal-Wallis test, and no statistically significant differences were found between all groups. Conclusions: To obtain maximum shear bonding strength, a combined technique of Er,Cr:YSGG and 37% phosphoric acid is useful even though it may be inconvenient.

      • KCI등재

        피질하 혈관성 치매 환자에서 단광자방출단층촬영과 Statistical Parametric Mapping을 이용한 뇌혈류 흐름의 분석 : Adaptation of Statistical Parametric Mapping

        양동원,김범생,김의녕,손형선,김상윤 대한치매학회 2002 Dementia and Neurocognitive Disorders Vol.1 No.1

        Background: Subcortical vascular dementia(SVaD) is relatively homogeneous subtype of VaD, but the mechanisms of cognitive dysfunction of subcortical VaD are not completely understood yet This study investigated the changes of cerebral blood flow(CBF) in patients with SVaD and the contribution of the white matter hyperintensity(WMHI) and clinical severity to CBF changes. Methods: 99mTc-ethyl cysteinate dimer single photon emission computed tomography(SPECT) was performed to measure the regional CBF and statistical parametric mapping(SPM)99 software was applicated to automated and objective analysis of the SPECT image data Twenty three patients (male 12, female 11) of mild to moderate dementia who met both the criteria of the DSM-IV and probable or possible NINDS-AIREN for VaD and have subcortical white matter changes and lacunar infarction on brain MRI and seventeen normal control subjects (male 7, female 10) were evaluated The severity of the WMHI was measured by semi-quantitative scale method proposed by Mantyla. The seventy of dementia was measured by clinical dementia rating (CDR) scale Results: SPM analysis of SPECT image revealed significantly reduced regional CBF in the right thalamus, left caudatd nucleus, cingulate, bilateral superior temporal, and left ventral subcallosal gyri in SVaD patients when it compared to normal controls (corrected p<0 001). Among four WMHIs, only the WMHI was associated with the small CBF reduction in the left superior temporal gyrus (uncorrected p<0 01) The reduction of CBF according to the severity of dementia was noted in the anterior and posterior association areas (uncorrected p<0 01). Conclusions: our study suggests that cognitive dysfunction of SVaD may be related with CBF reduction in the above mentioned brain areas, which probable are not associated with the severity of periventncular WMHI and dementia.

      • KCI등재
      • 포도상구균의 약제 내성 및 β-lactamase의 생산에 관하여

        양재윤,박상욱,이용진,조규봉,이연태 단국대학교 신소재기술연구소 1994 신소재 Vol.4 No.-

        항균제의 오남용으로 내성균의 출혈빈도가 매우 높아져 임상가에서는 환자치료에 어려움이 적지 않다. 특히 많은 균종중에서 병원감염의 문제가 되고 있고 포도상구균에 대한 내성빈도는 환자치료에 중요하다고 판단된다. 따라서, 1992년 12월부터 1993년 2월 사이에 서울대 병원에 내원(來院)한 환자로부터 총 108주의 포도상구균을 분양 받아 항균제 내성검사를 실시하였고 황색포도상구균의 경우는 β-lactamase 생산유무 확인 및 methicillin에 대한 MIC 농도를 비교하였으며, methicillin에 대하여 각기 다른 MIC농도를 갖는 균종에 대한 substrate 분해능 검사를 실시하여 다음과 같은 결론을 얻었다 (1). 항균제 내성검사를 실시한 108주의 포도상구균은 penicillin에 가장 높은 내성을 나타냈다. 황색포도상 구균의 경우는 97%, 표피포도상 구균의 경우 100%, coagulase 음성포도상구균의 경우 95.7%로 나타났다 (2). vancomycin의 경우는 전 균주가 감수성을 나타냈다 (3). methicillin에 대한 내성율은 41.4%로 나타났다. 이 내성균주들은 10가지 검사 항생제중 최고 9가지에 대한 항균제 내성을 나타내어 다약제 내성임을 알 수 있었다 (4). β-lactamase 생산 실험에서는 58균주의 황색포도상 구균중 53주가 양성을 나타내어 91.4%의 결과를 얻었다. β-lactamase 생산균주와 methicillin에 대한 내성균주가 반드시 일치하지는 않았다 (5). Spectrophotometric assay에서는 내성이 높은 균주와 낮은 균주간에 β-lactamase에 의한 substrate 분해능이 서로 유사하게 나와 황색포도상 구균의 methicililin에 대한 내성 획득은 β-lactamase 뿐만이 아닌 penicillin binding protein(PBP)의 구조적 변화로 인한 내성획득도 시사함을 알 수 있다. One hundred and eight Staphylococcus aureus strains were isolated from patients of Seoul National University Hospital from December 1992 to Feburary 1993. All strains were tested for their sensitivities against antibiotics. β-lactamse producing test was also performed in order to know the relationship between the methicillin resistance and β-lactamase production. Its activity was determined by direct spectrophotometric method. Initial velocities of hydrolysis of the antibiotics were monitored at wavelength 323 nm which corresponded to maximal change in absorbance between the unhydrolyzed substrate and the hydrolyzed product. The results are summarized as follows: 1. In antibiotics sensitivity test of 108 isolated strains of Staphylococcus, they showed hightest resistance to penicillin but all of tested strains were susceptible to vancomycin. 2. 41.4% of them showed resistance to methicillin. 3. All methicillin resistant strains were found to be multi-drug resistant, from 3 to 9 antibiotics. 4. 91.4%(53 out of 58) produced β-lactamase, β-lactamase producing strains did not always coincide with the methicillin resistant strains. 5. β-lactamase activities were similar among staphylococus strains, irrespective of their methicillin resistance.

      • 인터넷상에서 Ontology를 이용한 정보의 분류와 획득을 위한 지능형 에이전트의 설계

        양성기,이광옥,최길환,오창윤,배상현 조선대학교 통계연구소 2000 統計硏究所論文誌 Vol.2 No.1

        In this paper, we propose a new method of information gathering and text classification based on Internet. The number and diversity of information resources on the internet is increasing rapidly. As more information become available on the internet, it becomes increasingly difficult to acquire knowledge we need. A number of tools are available to help people search for the information they need. However, These tools are unable to interpret the result of their search due to lack of knowledge of domain. We need more intelligent system which facilitates personal activities of producing information such as surveying, writing paper and so on. We Implemented a system called ⅡRS(Intelligent Information Retrieval System) which helps people to acquire knowledge form information resources on the internet by gathering information and classification texts. It specifies the common background knowledge shared by the user and ⅡRS, allow ⅡRS to make inexact match between the user's request and the candidates, assigns user-oriented categories. We tested ⅡRS for gathering pages on the WWW and classification articles on the network news. The result of the experiments indicated that the ontology based approach enable us to use heterogeneous information resources on the internet.

      • n개의 파장을 분리 할 수 있는 WDM 광 결합기에 관한 연구

        尹成鉉,姜羊遠,洪昌熹 東亞大學校 1989 東亞論叢 Vol.26 No.1

        The optical coupler composed of polished single mode optical fiber can divide two wavelengths. If optical fiber is polished with paraller, very long coupling length is obtainahle, so can make WDM optical Coupler that dividahle n's Wavelengths. In this paper, we propose the condition of the WDM optical coupler that can divide two wavelengths to n's Wavelengths.

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