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        검색결과 215

        1.
        2024.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Acneiform eruptions are skin diseases that mimic acne vulgaris but lacking typical follicular blockage features. Acne vulgaris and some granulomatous variants of acneiform eruptions can involve Cutibacterium acnes, an anaerobic opportunistic bacterium; however, some cases remain resistant to standard antibiotics treatments. We report a 56-year-old male with facial acneiform granulomas unresponsive to long-term antibiotic and steroid treatments. The patient had no history of additional medications or other diseases, except symptomatic apical periodontitis in a molar toot. Both facial skin and dental lesions shared a key finding, intracellular infection of C. acnes within macrophages, despite differing histopathological features. The facial acneiform eruptions did not respond to initial minocycline treatment. However, following extraction of the infected tooth, the facial granuloma responded to the antibiotics and resolved without complications. PCR analysis confirmed C. acnes DNA in both the dental and skin biopsies. This case indicates the C. acnes-associated oral-skin-microbiome axis although a direct causal link between the distinct lesions could not be fully established. Odontogenic infection may act as reservoirs, impairing efficacy of antibiotic treatment. We recommend dental evaluation for case of facial acneiform granulomas that do not respond to antibiotics alone.
        4,000원
        2.
        2024.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        전통문화는 한 국가와 민족의 근본이며, 민족 정신의 중요한 구 성 요소이다. 오늘날 세계의 다원화된 문화 환경에서 전통문화의 중요성은 더욱 부각되고 있으며, 이는 민족의 문화적 기반이자 고 유한 문화적 상징으로 자리 잡고 있다. 중국의 전통 문학 명작에는 풍부한 내적 의미가 담겨 있어 현대 미술 창작의 중요한 모티프가 되고 있다. 조각 작품 《경양강상(景陽岡上)》과 《도발수류(倒拔垂 柳)》는 고전 문학 명작 《수호전(水滸傳)》에서 소재를 가져왔으 며, 원작을 존중하는 바탕 위에서 전통문화 요소와 현대 예술 기법 을 유기적으로 융합하여 새로운 시대적 배경 속에서 전통문화를 계 승하고 혁신을 시도한 유익한 작품이다. 문화의 전승은 혁신과 분 리될 수 없으며, 이 작품들은 전통과 현대의 융합을 통해 전승과 혁신을 병행하고, 현대 조형 예술 기법으로 전통 문화의 매력을 충 분히 보여준다. 중국 전통 예술에서 형태 창작에 대한 의상적(意象 的) 표현은 더욱 독특한 형식미와 깊이 있는 문화적 함의를 지니고 있다. 《경양강상(景陽岡上)》과 《도발수류(倒拔垂柳)》는 창작 과 정에서 전통 조각 기법을 넘어서 참신한 형식 언어를 사용하였으 며, 구성, 인물 표정의 조형, 동적 표현과 정적 표현의 조화, 전체적 간결함과 부분적 세밀함의 결합, 이미지 경계의 실루엣 처리, 인물· 동물·배경의 형태 구성, 전통 예술 요소와의 융합 등 여러 측면에 서 혁신적인 시도와 사고를 담고 있다. 무송(武松)과 노지심(魯智 深)의 형상에는 의상적 조형 기법을 적용하였고, 전체적인 형상은 간결하게 요약하였으며, 특징을 강조할 수 있는 세밀한 부분에서는 사실주의적 표현과 결합하여 표현하였다. 전통 문화 소재를 표현하 는 데 있어 현대적 형식 언어와 예술 기법을 융합하여, 현대적 미 적 관점으로 전통 문화의 매력을 재해석하고 현대적 미감을 충족시키는 예술 작품을 창조하는 것을 목표로 하고 있다.
        5,100원
        3.
        2024.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The performance of various types of silencers used to reduce the micropressure waves radiated from ventilation holes and inclined shafts, which are being studied as measures to reduce micropressure waves in railway tunnels, was evaluated to find an effective silencer. In order to find the optimal silencer, the magnitude and frequency characteristics of the pressure waves emitted from the inclined shaft were analyzed to find an excellent silencer. The evaluation showed that the model with a porous cylinder and a small diameter outer tube was the simplest but performed the best.
        4,000원
        4.
        2024.10 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        In this study, a composite material suitable for flexible transparent electrodes was fabricated using Norland Optical Adhesive 68 (NOA 68), an ultraviolet (UV) curable polymer, and silver nanowires (Ag nanowire, AgNW). The mechanical behavior of this composite was then analyzed. A AgNW network structure was embedded in the NOA 68 polymer and cured using UV energy. The composite was prepared with an AgNW network structure formed approximately 4 μm from the top of the NOA 68 matrix. Tensile test specimens were prepared according to ASTM standards, and tensile tests were conducted at room temperature in air. Scanning electron microscopy (SEM) and tensile tests were used to analyze the changes in mechanical behavior according to UV exposure time and the presence of AgNW. The results showed that as UV curing time increased, the yield strength of the composite increased while the elongation decreased. Regardless of the presence of the AgNW filler, the stress-strain curves of the ductile polymer exhibited the typical mechanical behavior of semi-crystalline polymers as UV curing time increased, characterized by strain softening. It was also confirmed that the composite impregnated with AgNW exhibited higher strength in response to changes in mechanical properties due to UV curing.
        4,000원
        5.
        2024.07 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        흉강담도루는 흔하지 않지만 가끔 경피경간담낭배액술 후에 발생할 수 있다. 본 증례는 경피경간담낭배액술 시행 후 발생한 흉강담도루로 진단받은 83세의 한국인 남성에 관련한 것으로, 경구용 담도경을 이용한 내시경적 경유두담낭배액술(SpyGlass DS system)을 통해 담낭 내 압력을 줄여 흉강으로 담즙의 유출을 줄일 수 있었다. 이후 환자는 호전되어 퇴원하였다.
        3,000원
        7.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Dissolved organic matter (DOM) is a key component in the biogeochemical cycling in freshwater ecosystem. However, it has been rarely explored, particularly complex river watershed dominated by natural and anthropogenic sources, such as various effluent facility and livestock. The current research developed a new analytical method for TOC/TN (Total Organic Carbon/Total Nitrogen) stable isotope ratio, and distinguish DOM source using stable isotope value (δ13C-DOC) and spectroscopic indices (fluorescence index [FI] and biological index [BIX]). The TOC/TN-IR/MS analytical system was optimized and precision and accuracy were secured using two international standards (IAEA-600 Caffein, IAEA-CH-6 Sucrose). As a result of controlling the instrumental conditions to enable TOC stable isotope analysis even in low-concentration environmental samples (<1 mgC L-1), the minimum detection limit was improved. The 12 potential DOM source were collected from watershed, which includes top-soils, groundwater, plant group (fallen leaves, riparian plants, suspended algae) and effluent group (pig and cow livestock, agricultural land, urban, industry facility, swine facility and wastewater treatment facilities). As a result of comparing characteristics between 12 sources using spectroscopic indices and δ13C-DOC values, it were divided into four groups according to their characteristics as a respective DOM sources. The current study established the TOC/TN stable isotope analyses system for the first time in Korea, and found that spectroscopic indices and δ13C-DOC are very useful tool to trace the origin of organic matter in the aquatic environments through library database.
        4,000원
        8.
        2023.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        An irradiation hardening of Inconel 718 produced by selective laser melting (SLM) was studied based on the microstructural observation and mechanical behavior. Ion irradiation for emulating neutron irradiation has been proposed owing to advantages such as low radiation emission and short experimental periods. To prevent softening caused by the dissolution of ' and '' precipitates due to irradiation, only solution annealing (SA) was performed. SLM SA Inconel 718 specimen was ion irradiated to demonstrate the difference in microstructure and mechanical properties between the irradiated and non-irradiated specimens. After exposing specimens to Fe3+ ions irradiation up to 100 dpa (displacement per atom) at an ambient temperature, the hardness of irradiated specimens was measured by nanoindentation as a function of depth. The depth distribution profile of Fe3+ and dpa were calculated by the Monte Carlo SRIM (Stopping and Range of Ions in Matter)-2013 code under the assumption of the displacement threshold energy of 40 eV. A transmission electron microscope was utilized to observe the formation of irradiation defects such as dislocation loops. This study reveals that the Frank partial dislocation loops induce irradiation hardening of SLM SA Inconel 718 specimens.
        4,000원
        11.
        2023.07 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        This study aimed to address the limitations of traditional plasma nitriding methods by implementing a short-term plasma oxy-nitriding treatment on the surface of AISI 420 martensitic stainless steel. This treatment involved the sequential formation of nitride and oxide layers, to enhance surface hardness and corrosion resistance, respectively. The process resulted in the formation of a 20 μm-thick nitride layer and a 3 μm-thick oxide layer on the steel surface. Initially, the hardness increased by 2.2 times after nitriding, followed by a subsequent decrease of approximately 31 % after oxidation. While the nitriding process reduced corrosion resistance, the subsequent oxidation process led to the formation of a passive oxide film, effectively resolving this issue. The pitting corrosion of the oxide passive film started at 82.6 mVssc, providing better corrosion resistance characteristics than the nitride layer. Consequently, the trade-off between surface hardness and corrosion resistance in plasma oxy-nitrided AISI 420 martensitic stainless steel is anticipated to be recognized as an innovative and comprehensive surface treatment process for biomedical components.
        4,000원
        12.
        2023.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, machine learning models are proposed to predict the Vickers hardness of AlSi10Mg alloys fabricated by laser powder bed fusion (LPBF). A total of 113 utilizable datasets were collected from the literature. The hyperparameters of the machine-learning models were adjusted to select an accurate predictive model. The random forest regression (RFR) model showed the best performance compared to support vector regression, artificial neural networks, and k-nearest neighbors. The variable importance and prediction mechanisms of the RFR were discussed by Shapley additive explanation (SHAP). Aging time had the greatest influence on the Vickers hardness, followed by solution time, solution temperature, layer thickness, scan speed, power, aging temperature, average particle size, and hatching distance. Detailed prediction mechanisms for RFR are analyzed using SHAP dependence plots.
        4,000원
        14.
        2023.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study compares the abundance and community structure of zooplankton organisms from pelagic regions, and considers particularly the trophic levels vs. zooplankton abundances and biomass. Zooplankton samples were collected three times from May to November 2022, at 30 temperate lakes and reservoirs, which belong to four different river basins. The total zooplankton abundance, biomass and species index were showed considerable spatial variation. The spatial pattern of rotifer abundance was similar to that of total zooplankton abundance, while there were not showed similar patterns of zooplankton biomass (μg L-1) in lentic ecosystems. The rotifer strongly dominated the zooplankton assemblage in smaller lentic system than that of larger. A total of 130 species of zooplankton were identified (83 rotifers, 34 cladocerans and 13 copepods). The total average of zooplankton abundance and biomass were 213.7±342.3 Ind. L-1 (n=129) and 1382.8±1850.4 μg L-1, respectively. Total and average of zooplankton abundance were usually dominated by the rotifers (>56.9%), while those of zooplankton biomass were dominated by the cladocerans and copepods (>73.6%) in lentic ecosystems. Considering the Trophic State Index (TSI), the factors of zooplankton abundance and biomass were included in between meso- and eutrophic states (27 lakes, 90% of all). The mean abundance and biomass of zooplankton in eutrophic systems were higher than that of meso- and hypertrophic systems. From this result, we suggest that management strategy for the lentic ecosystem water environment has to be focused more on small-sized lakes and reservoirs, in terms of zooplankton assemblages.
        4,200원
        15.
        2022.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study was evaluated based on the items of KS B 6389. The study on the calculation of angular error and measurement uncertainty of HRc hardness measurement using statistical techniques using Rockwell measurement specimens with different hardness values ​​was analyzed, and the results were derived according to the change in the angle of the indenter part of the hardness tester and the specimen. As a result of the experiment, the test statistic P values ​​for angle changes such as 0°, 1°, and 2° were all 0.000 using the HRc 30 and 40 measurement specimens, so it was confirmed through the experiment that a significant difference occurred between them. In addition, the extended uncertainty value was calculated as 0.612 at the 95.45% confidence level, and the fact that the hardness test value came out smaller than the existing test value as the inclination angle increased was verified through experiments.
        4,000원
        16.
        2022.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        목적: 입체경에서 기하학적 단안 단서를 타깃의 배경에 적용하여 거리감 지각의 변화를 확인하였으며, 가상현실에 서 거리감의 효과적인 구현 방법을 분석하였다. 방법 : 타깃의 배경에 사용된 단안 단서는 결의 밀도, 선형 전망, 대기 전망 및 음영이었다. 결의 밀도 단서 및 선형 전망 단서는 선의 개수와 대비도, 대기 전망 단서 선의 개수와 대비도 차이, 음영 단서는 음영의 농도와 범위 를 각각 변수로 선정하였다. 타깃은 모든 대상자에게 무작위로 제시하였으며, 원거리 및 근거리에서 검사 후 5점 척도의 설문조사를 통해 거리감 변화를 확인하였다. 또한, 거리감 변화에 대해 대상자의 지각이 의도한 것과 일치 했을 때 긍정적, 그렇지 못했을 때 부정적 효과로 구분하고, 거리감 변화의 효율을 평가하였다. 결과 : 원거리와 근거리 모두 단안 단서의 변수에 대해 의도한 것과 대부분 일치하는 것으로 확인되었으며, 근 거리는 일부 변수 조정 항목에서 다소 차이가 발생했다. 또한, 거리감 변화 효과는 결의 밀도 단서 및 대기 전망 단서에 의해 선의 개수가 변화했을 가장 높았고, 일부 유의하였다(p<0.050). 결론 : 입체경에서 대상자의 거리감은 주시거리가 동일해도 타깃의 배경에 적절한 단안 단서를 제공하여 조정 이 가능한 것으로 확인되었다. 원거리 및 근거리 입체시표의 기하학적 단서 중 결의 밀도 및 대기 전망 단서에서 선의 개수를 변화시켰을 때 거리감 지각 변화의 효과가 가장 높은 것으로 나타났다. 보다 정확한 거리감 지각을 위해서는 조절 및 폭주 변화 등을 추가한 후속 연구가 필요할 것으로 판단된다.
        5,700원
        17.
        2022.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The effect of the laser beam diameter on the microstructure and hardness of 17-4 PH stainless steel manufactured via the directed energy deposition process is investigated. The pore size and area fraction are much lower using a laser beam diameter of 1.0 mm compared with those observed using a laser beam diameter of 1.8 mm. Additionally, using a relatively larger beam diameter results in pores in the form of incomplete melting. Martensite and retained austenite are observed under both conditions. A smaller width of the weld track and overlapping area are observed in the sample fabricated with a 1.0 mm beam diameter. This difference appears to be mainly caused by the energy density based on the variation in the beam diameter. The sample prepared with a beam diameter of 1.0 mm had a higher hardness near the substrate than that prepared with a 1.8 mm beam diameter, which may be influenced by the degree of melt mixing between the 17-4 PH metal powder and carbon steel substrate.
        4,000원
        18.
        2022.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 부·울·경의 전국동시지방선거 중 시·도지사 선거결과를 통해 보수정당으로의 회귀 가능성과 향후 선거 결과에 대한 전망을 하는 것이 주요한 목적이다. 실제로 전국동시지방선거에서 부산은 국민의힘이 더불 어민주당을 7:1로 이겼고, 울산에서는 국민의힘이 6:1로 우세했다. 그리 고 경남에서는 국민의힘과 더불어민주당의 전적은 6:2의 결과를 보였다. 이것은 지역주의와 지연주의가 부·울·경에서 강하게 작용하고 있다는 것 을 보여준다. 제8회 전국동시지방선거에서 국민의힘이 전국에서 승리하 였고, 특히 부·울·경 지역에서는 양당 후보 간 20%~35%p의 큰 격차를 보였다. 그리고 부·울·경의 역대선거 결과를 비교분석해 볼 때, “유권자 의 선택이 중요하며, 그 점에서 부·울·경은 보수정당 지지로 선회했고, 이 흐름은 당분간 지속할 것으로 전망된다. 하지만, 박근혜 대통령의 탄 핵이라는 큰 변수는 제7회 전국동시지방선거에서 더불어민주당의 전국적 인 승리를 안겨주었다는 점에서 정치적 이슈에 따라 유권자의 선택이 언 제든 변화할 수 있다.
        6,700원
        19.
        2022.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        목적 : 입체경으로 구현된 가상공간에서 측정한 사위검사를 하웰 시표를 기반으로 하는 기존 검사와 비교하여 효용성을 알아보고자 하였다. 방법 : 전체 대상자는 51명(20~39세)으로 전신질환, 안질환, 억제가 없고, 입체시가 40 sec 이상, 나안 또는 교정시력이 양안 1.0 이상인 사람을 선정하였다. 입체경의 광학렌즈 굴절력은 +3.00 D, +5.00 D, +10.00 D이 고, 광학중심점 간 거리는 62.00 mm이었다. 하웰 시표를 기반으로, 기존과 입체경용 사위도 검사 시표를 제작하 였으며, 검사거리 500.00 cm, 40.00 cm, 33.00 cm에 대해 수평과 수직사위도 검사를 무작위로 수행하였으며, 계산 조절성폭주비를 구하였다. 결과 : 검사거리 500.00 cm, 40.00 cm 및 33.00 cm에서 측정한 기존, +3.00 D, +5.00 D, +10.00 D 입체경 에서 수평사위(△)는 각각 -1.18±1.71, +2.39±3.46, +2.23±3.36, +2.36±3.31(500.00 cm), -3.88±4.17, -4.92±5.92, -4.98±5.70, -4.91±5.58(40.00 cm), 및 -5.53±4.82, -6.50±6.67, -6.49±6.59, -6.38±6.54 (33.00 cm), 수직사위(△)는 각각 -0.03±0.97, -0.03±0.99, -0.03±0.87, +0.02±1.00(500.00 cm), 0.00±0.92, -0.05±1.00, -0.09±1.01, -0.02±1.02(40.00 cm), 및 -0.05±0.99, -0.01±1.00, -0.11±1.02, -0.05±0.99(33.00 cm)로 나타났다. 입체경의 원거리 수평사위에서 더 내사위, 근거리는 더 외사위 방향으로 나 타났으며, 원거리만 통계적으로 유의한 차이가 있었고(p<0.050), 수직사위는 유의한 차이가 없었다(p>0.050). 계 산 조절성폭주비(△/D)는 각각 5.18±1.24, 3.34±1.45, 3.38±1.37, 3.36±1.35(40.00 cm), 및 4.81±1.22, 3.30±1.41, 3.36±1.41, 3.35±1.38(33.00 cm)이었으며. 입체경에서 더 낮았으며, 유의한 차이가 있었다 (p<0.050). 결론 : 입체경을 이용한 사위도 검사는 구현된 가상공간에 대한 거리감 인지가 실제공간과 다르기 때문에 원거 리 과폭주, 근거리 저폭주의 영향이 발생되었다. 실제공간과 유사한 수준을 가지기 위해서는, 거리감 인지를 증가 를 위한 주변부 가상공간에 경험적 단서를 추가시킬 필요가 있다고 판단된다.
        4,000원
        20.
        2022.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        PURPOSES : The exposed aggregate concrete pavement (EACP) is adopted to achieve low traffic noise and long-term skid resistance in European countries such as Belgium and Germany. In Korea, it is first introduced at the Myeon Cheon field site in 2010. It reduces 3 dB(A) from tire–pavement noise compared with transverse tining. Recent investigations show that EACP can reduce tire–pavement noise by an additional 5 dB(A) compared with transverse tining. In this study, the tire–pavement interaction noise of EACP is compared with that of conventional pavements such as asphalt pavement, next-generation concrete surfaces (NGCS), and transverse tining. METHODS : EACP is constructed at two field sites on the SOC research center and Yeo-Ju test road to compare the noise level via close proximity noise measurement. In addition, the noise is measured using two vehicle type based on vehicle speeds of 60, 80, and 100 km/h. RESULTS : The results of noise measurement obtained from the SOC research center are as follows: Porous asphalt pavement 92.8 dB(A), HMA 96. dB(A), transverse tining 100.1 dB(A), and 8 mm EACP 97 dB(A) at a driving speed of 80 km/h. For the case of the Yeo-Ju test road. The noise levels at a driving speed of 80 km/h are as follows: 6 mm EACP, 93.6 dB(A); asphalt grooving pavement, 94.72 dB(A); 8 mm EACP, 95.2 dB(A); NGCS, 95.2 dB(A); transverse tining, 104.1 dB(A). CONCLUSIONS : The result of noise measurement of two sites in the SOC research center and test road shows that the noise level of the 6 mm EAC is lower than that of concrete pavement, such as tining and NGCS, and similar to that of asphalt pavement. In addition, the noise level of the 8 mm EAC is similar to that of the NGCS pavement. The noise reduction effect of the EAC is greater when small-sized coarse aggregates with lower flat and elongation ratios are used.
        4,000원
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