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        검색결과 2,202

        1.
        2024.10 구독 인증기관·개인회원 무료
        도로분야와 관련된 기준에서 도로법, 도로의 구조·시설 기준에 관한 규칙, 도로 건설기준(KDS/KCS 44 00 00) 등 관련 법령을 근거로 제정된 기준은 상위기술기준으로 분류되며 그 외 지침, 편람, 매뉴얼, 가이드라인 등은 하위기술기준으로 구분된다. 상위기술기준은 도 로법, 건설기술진흥법 등을 근거로 제정되어 활용되고 있으나, 지침, 편람, 가이드라인 등으로 분류되는 하위기술기준은 소관부서에서 주관하여 필요한 상황에 따라 제정하여 현장에서 활용되고 있다. 법령을 근거로 하는 상위기술기준은 국가건설기준센터, 소관부서 등 에 의해 지속적으로 관리되고 있는 반면에 하위기술기준은 제정 당시 시점의 상위기술기준을 준용하여 제정 후 현행화 등의 후속 관 리가 체계적으로 수행되고 있지 않아 현행 상위기술기준과의 연계성이 떨어지고, 상충되는 문제가 야기되고 있다. 본 연구에서는 현재 까지 발행, 고시 또는 배포된 도로분야의 하위기술기준의 관리를 위한 현황 조사와 함께 전문가 검토를 통한 하위기술기준의 활용성 을 확보하기 위한 방안을 모색하기 위한 기초자료를 마련하고자 하였다. 도로분야 하위기술기준에 대한 현황 조사를 수행한 결과에서 는 현재 150여 개의 하위기술기준이 배포된 것으로 파악되었다. 조사 결과를 바탕으로 도로분야 설계 및 도로 시공 분야 전문가 검토 를 통해 현장에서의 활용 가치가 있는 하위기술기준은 존치하는 방향으로, 현행 상위기술기준과의 연계성, 현장 활용도가 떨어지는 하 위기술기준은 폐지하는 방향으로 분석하여 도로분야 하위기술기준의 현장 활용성 확보를 위한 자료를 마련하였다.
        3.
        2024.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Habitat environment and food sources of fish, benthic macroinvertebrates, and brown trout (Salmo trutta) downstream of Soyang River Dam were analyzed. Water temperature at the site where brown trout was identified ranged from approximately 12.4 to 13.4°C, confirming that this environment could provide an optimal water temperature for the growth of brown trout. Most of the riverbed structures at this site had a high proportion of cobble and pebble substrates. Brown trout constituted less than 5% of the total fish population, more abundant in the upstream. The total lengthweight relationship of brown trout showed a parameter b value of 3.234, with the condition factor (K) increasing with length. Dominant benthic macroinvertebrates were Limnodrilus gotoi and Chironomidae spp. (non-red type). Stomach content analysis indicated that brown trout primarily consumed aquatic insects (R.A., 73.8%), non-insects (R.A., 23.3%), ground insects (R.A., 2.7%), and fish (R.A., 0.2%, TL: 246 mm). Correlation analysis revealed a positive relationship between total length and species preferring flowing water (p<0.05) and a negative relationship of total length with species favoring low-flow, sandy habitats (p<0.05). Larger brown trout showed active feeding behavior and resilience to flow speed and riverbed structure. The primary food source for the largest brown trout (TL: 246 mm) was Hypomesus nipponensis. Future analyses should include brown trout with a total length of 30 cm or more. Given that samples were limited, comprehensive population management will require ongoing research.
        5,200원
        4.
        2024.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study conducted field surveys targeting benthic macroinvertebrates and fish in Andong Dam and Yeongsan River, with the specific aim of analyzing bluegill stomach contents. Bluegills in Andong Dam ranged from 40-220 mm, with 93.0% between 80-220 mm, while those in Yeongsan River ranged from 50-210 mm, with 71.4% between 120-210 mm. The highest feeding rates in both sites were for Chironomidae spp., with findings of 72.6% in Andong Dam and 80.4% in Yeongsan River. In Andong Dam, H. nipponensis and Baetidae sp. were also significant at 17.5% and 6.5%, respectively, while in Yeongsan River, Baetidae sp. (7.5%) and Hymenoptera sp. were the next most common at 3.8%. The EI index showed that bluegills generally avoided H. nipponensis and S. tsuchigae (-0.373 and -0.975) whereas they preferred Chironomidae spp. (0.759, 0.892) and Baetidae sp. (0.723). The parameter b values of the total length-weight relationship of bluegill were calculated as 3.452 in Andong Dam and 3.449 in the Yeongsan River, respectively. The slope values of the condition factor were 0.0067 in Andong Dam and 0.0065 in the Yeongsan River. Both values were positive, indicating that the nutritional status of bluegill was good. Aquatic insects constituted the primary food source, particularly in Yeongsan River. Feeding patterns did not significantly differ by habitat orientation groups, but Yeongsan River bluegills consumed more diverse food sources. In Andong Dam, larger bluegills likely consume food sources with larger biomass, while Yeongsan River’s diverse and abundant food sources support opportunistic feeding tailored to the water ecological environment.
        4,600원
        5.
        2024.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Seismic fragility curves present the conditional probability of damage to target structures due to external seismic load and are widely used in various ways. When constructing such a seismic fragility curve, it is essential to consider various types and numbers of ground motions. In general, the earthquake occurrence characteristics of an area where the target structure of the seismic fragility curve exists are analyzed, and based on this, appropriate ground motions are selected to derive the seismic fragility curve. If the number of selected ground motions is large, the diversity of ground motions is considered, but a large amount of computational time is required. Conversely, if the number of ground motions is too small, the diversity of ground motions cannot be considered, which may distort the seismic fragility curve. Therefore, this study analyzed the relationship between the number of ground motions considered when deriving the seismic fragility curve and the parameters of the seismic fragility curve. Using two example structures, numerical analysis was performed by selecting a random number of ground motions from a total of two hundred, and a seismic fragility curve was derived based on the results. Analysis of the relationship of the parameter of the seismic fragility curve and the number of selected ground motions was performed. As the number of ground motions considered increases, uncertainty in ground motion selection decreases, and when deriving seismic fragility curves considering the same number of ground motions, uncertainty increases relatively as the degree of freedom of the target structure increases. However, considering a relatively large number of ground motions, uncertainty appeared insignificant regardless of increased degrees of freedom. Finally, it is possible that the increase in the number of ground motions could lower the epistemic uncertainty and thus improve the reliability of the results.
        4,000원
        6.
        2024.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The damage to structures during an earthquake can be varied depending on the frequency characteristics of seismic waves and the geological properties of the ground. Therefore, considering such attributes in the design ground motions is crucial. The Korean seismic design standard (KDS 17 10 00) provides design response spectra for various ground classifications. If required for time-domain analysis, ground motion time series can be either selected and adjusted from motions recorded at rock sites in intraplate regions or artificially synthesized. Ground motion time series at soil sites should be obtained from site response analysis. However, in practice, selecting suitable ground motion records is challenging due to the overall lack of large earthquakes in intraplate regions, and artificially synthesized time series often leads to unrealistic responses of structures. As an alternative approach, this study provides a case study of generating ground motion time series based on the hybrid broadband ground motion simulation of selected scenario earthquakes at sites in the Nakdonggang delta region. This research is significant as it provides a novel method for generating ground motion time series that can be used in seismic design and response analysis. For large-magnitude earthquake scenarios close to the epicenter, the simulated response spectra surpassed the 1000-year design response spectra in some specific frequency ranges. Subsequently, the acceleration time series at each location were used as input motions to perform nonlinear 1D site response analysis through the PySeismoSoil Package to account for the site response characteristics at each location. The results of the study revealed a tendency to amplify ground motion in the mid to long-period range in most places within the study area. Additionally, significant amplification in the short-period range was observed in some locations characterized by a thin soil layer and relatively high shear wave velocity soil near the upper bedrock.
        4,800원
        7.
        2024.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study conducted morphological and molecular phylogenetic analyses on three presumed natural interspecific hybrids of the genus Sarcocheilichthys, collected from the main stream of the Seomjin River and its tributary, Dongbokcheon Stream, as well as their parent species, S. nigripinnis morii and S. variegatus wakiyae, to identify whether they are natural hybrids and to determine their maternal and paternal species. The results of the molecular phylogenetic analysis clearly demonstrated that the three presumed natural hybrids are indeed natural hybrids of S. nigripinnis morii and S. variegatus wakiyae, with S. nigripinnis morii identified as the maternal species and S. variegatus wakiyae as the paternal species. The three natural hybrids exhibited intermediate or unique morphological traits that were not biased towards either parent species, and distinct morphological characteristics were observed in the dorsal fin and caudal fin. In the water bodies where the natural hybrids were collected, a variety of Acheilognathinae species and spawning hosts coexisted alongside the parent species S. nigripinnis morii and S. variegatus wakiyae. It is presumed that the overlapping spawning periods and locations of S. nigripinnis morii and S. variegatus wakiyae promoted the occurrence of hybrids. The unidirectional occurrence of natural interspecific hybridization is attributed to interspecific competition and population imbalance, and the sneaker behavior of S. variegatus wakiyae males was proposed as an important mechanism.
        4,600원
        8.
        2024.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 충북 청주시 소재 C대학교 인근 커피숍의 외부 및 내부사용 접근성 실태를 시설의 접근과 이 동에 있어서 약자로 간주되는 수동 휠체어 사용자 관점에서 평가하여 개선 방안을 제안하고 접근성 실 태를 시각적으로 확인할 수 있도록 돕는 접근성맵 제작하는 것을 목적으로 진행되었다. C대학교 인근 4개 동의 115개 커피숍을 대상으로 2024년 3월부터 5월까지 자체 제작한 체크리스트를 이용하여 현장 조사를 실시하였으며, 그 결과를 바탕으로 각 동별 커피숍 접근성맵을 제작하였다. 주요 결과와 적용점 은 다음과 같다. 첫째, 113개 진입형 및 혼합형 매장 중 수동휠체어 사용자의 자력진입과 내부 자력주행 및 사용이 모두 가능한 매장은 15.0%에 불과한 반면 수동휠체어 사용자의 자력진입이 불가능하거나 자력 내부 주행 및 사용이 불가능한 매장은 75.2%로 나타났다. 둘째, 비진입형 및 혼합형 커피숍 11개소 의 경우 수동휠체어 사용자의 자력 주문 및 대기가 가능한 매장은 단 한 개소도 나타나지 않았으며, 수동 휠체어 사용자의 주문과 대기가 불가능한 경우가 54.5%였다. 셋째, 충족률이 저조한 항목 중 가장 빈번 한 항목은 계산대나 키오스크 등의 무릎공간 확보였다.
        4,000원
        9.
        2024.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 논문은 죽음을 사유하는 인간, ‘호모 싸나토스’(Homo Thanatos)의 죽음인식을 분석하여 죽음 불안의 본질을 궁구하고 인간이 왜 죽음을 회피하고 죽음을 초월하려는 지에 대해 탐구한다. 또한 호모 싸나토스로서의 인간이 죽음을 사유함을 통해 삶의 가치를 재발견하고, 궁극적으로 죽음을 삶의 자연스러운 과정으로 받아들이며, 삶의 진정한 자아와 의미를 찾을 수 있는지에 대해 논의한다. 아울러 ‘죽음학’인 ‘싸나톨로지’(Thanatology)를 통해 죽음인식의 출현을 탐구하고, 문학에서 인간의 근원적인 질문인 죽음이 어떻게 묘사되고 죽음에 대한 통찰력을 주는지, 그리고 죽음에 대한 인식이 역사 전반에 걸쳐 어떻게 진화해 왔는지 탐색해본다. 그 과정 속에 서로 다른 시대와 사회적 맥락이 죽음에 대한 이해와 경험을 어떻게 형성해 왔는지 보여준다. 특히 AI 시대의 디지털 불멸의 혼란 속에서 죽음에 대한 사유와 인식이 더욱 필요함을 강조한다. 결론적으로 죽음 인식으로 삶의 성찰과 의미를 찾는 호모 싸나토스로서의 실존을 위해 진지한 열린 토론과 학술 연구가 보다 활발하게 이루어져야 한다.
        5,800원
        10.
        2024.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        4,900원
        11.
        2024.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study is about the design of an elastic support system to isolate the structural noise of the low accumulator of the naval artillery among the equipment mounted on a warship. As the structural noise measurement value of the low accumulator transmitted to the ship exceeded the standard value, a method of applying an elastic mount between the equipment and the ship was devised to isolate the structural noise. By calculating the target vibration isolation efficiency, the vibration isolating system was designed in consideration of design factors such as the system's natural frequency and static displacement. Finally, the performance of the structural noise reduction of the designed vibration isolating system was verified by evaluating the structural noise transmitted to the foundation plate of the equipment from the low accumulator to which designed elastic support system was applied.
        4,000원
        12.
        2024.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        이 연구는 통합기술수용이론(UTAUT)을 확장한 UTAUT2 모델을 활용 하여 치의학과 학생들의 UBT 수용의도에 영향을 미치는 요인을 분석하 고, 성별에 따른 조절효과를 검토하였다. 이를 위해 한 국립대학교 치의 학과 졸업시험에 응시한 학생 157명을 대상으로 설문조사를 실시하였다. 설문조사는 연구참여자의 성별, 나이, 입학 유형, 태블릿 PC 보유 여부, 스마트기기 활용 능력 등 인구통계학적 정보와 스마트기기 사용 경험, 그리고 UTAUT2 모델에 기반한 성과기대, 노력기대, 사회적 영향, 촉진 조건, 습관 등 요인과 UBT 수용의도를 평가하는 21개의 문항 등 총 27 개의 문항을 활용하였다. 설문조사 분석 결과에 따르면 사회적 영향과 습관 요인이 치의학과 학생들의 UBT 수용의도에 유의미한 영향을 미쳤 으며, 습관 요인과 UBT 수용의도간 관계에 대한 성별의 조절효과가 확 인되었다. 이러한 결과를 바탕으로 UBT 도입을 촉진하기 위해 학생들의 긍정적인 인식을 높이는 홍보 활동, 정기적인 연습 기회 제공, 성별 맞춤 형 접근, 기술적 지원과 자원 제공 등의 전략을 제안하였다.
        5,500원
        13.
        2024.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        PURPOSES : This study aims to improve pedestrian safety by analyzing the effectiveness of displaying the remaining time of red crosswalk signal that provide pedestrians with information regarding the time available for crossing METHODS : This study analyzes the effectiveness of newly installed displays for remaining time of the red pedestrian signal in the cities of Yeongcheon and Yeongju in Gyeongsangbuk-do. The data collection was divided into periods before and after the installation of the facilities. Pedestrian departure delays were measured at the introduction and subsequent stages of installation, and changes in pedestrian behavior were quantitatively analyzed. Statistical significance of the results was verified using a t-test. RESULTS : For the displays of remaining time of crosswalk red signals installed in Yeongju, the pedestrian departure loss time decreased from 3.36 seconds before installation to 1.85 seconds after installation. Additionally, compared to the pre-installation situation, the postinstallation situation showed a relatively lower standard deviation, indicating that the pedestrians exhibited a more consistent pattern when starting to cross. Similarly, for the displays of remaining time of crosswalk red signal installed in Yeongcheon, the pedestrian departure loss time decreased from 2.37 seconds before installation to 1.89 seconds after installation. As in Yeongju, the post-installation situation showed a relatively lower standard deviation, indicating that the pedestrians exhibited a more consistent pattern when starting to cross. CONCLUSIONS : In this study, we verified the effect of newly installed pedestrian countdown signals on improving pedestrian safety at two intersections in Yeongcheon and Yeongju, which were selected through a survey of traffic accident-prone areas in Gyeongsangbuk-do. Pedestrian countdown signals were quantitatively confirmed to have a positive impact on pedestrian safety. Based on the observations, it is anticipated that expanding the installation of these signals will have a positive effect on pedestrian safety, particularly in areas with frequent traffic accidents and the senior and children protection zones. Results of this study indicate that the proposed policy measures are expected to strengthen pedestrian safety and reduce traffic accidents.
        4,000원
        14.
        2024.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        PURPOSES : Construction standards have resolved overlaps and conflicts between different standards and fields through the introduction of a code system. However, the sub-technical standards were established based on the construction standards at the time of their creation and have not been revised. This has resulted in poor integration and conflicts with revised construction standards, reducing their practical applicability in the construction field. Consequently, to enhance the practical applicability of sub-technical standards and ensure their integration with construction standards, this study aimed to devise technical guidelines for sub-technical standards. METHODS : A brainstorming session was conducted with field experts to evaluate the applicability and necessity of the currently distributed sub-technical standards in the field. Each sub-technical standard was reviewed to determine whether it should be retained or abolished. On the basis of the review results, this study developed a set of draft technical guidelines (Korean Design Standard Guideline (KDSG)/Korean Construction Specification Guideline (KCSG)) for the sub-technical standards that required retention. RESULTS : A comprehensive survey of sub-technical standards identified a total of 154 standards. Of these, 109 were deemed necessary to retain, whereas 45 were considered unnecessary to retain. Among the sub-technical standards requiring retention, 20 were selected for the development of technical guidelines based on their relevance and applicability to the construction standards. A draft of these technical guidelines was subsequently prepared. CONCLUSIONS : A plan was devised to assign technical guideline codes to 20 subordinate technical standards that were deemed consistent with the road construction standards (KDS/KCS 44 00 00). This approach can provide a foundation for reorganizing the system of road construction standards and subordinate technical standards, thereby enhancing their practical usability in the construction field.
        4,300원
        15.
        2024.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study sought to reveal the architectural characteristics of Quonset church built in the Archdiocese of Gwangju, and the conclusions are as follows. The Quonset structure, which was used as a military barracks during World War II and was designed to be easily assembled and disassembled quickly, was used in Damyang, Hwasun, and Gokseong churchs. They were all built in 1958, after the Korean War, and can be related to the historical background of the rapid increase in the number of Catholics. They are utility buildings that can accommodate many believers, that is, large quonsets measuring 40 feet (width) x 100 feet (length). The floor plan was largely divided into two spaces, with about 3/4 reserved for the nave and altar, and the remaining 1/4, or 24 to 30 feet, used as a sacristy or confessional. The cross-section is a semicircle with a radius of 20 feet, framed by 6-inch ribs, and its unique structure, in which bricks are stacked on the outside to form the exterior, makes it different from a typical brick church. Unlike other stone churches built around the same time, Quonset church was not expanded. This may be due to the difficulty in supplying special materials such as the ribs that make up the frame, as well as the absence of relevant experts.
        4,000원
        16.
        2024.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        PURPOSES : The skid resistance between tires and the pavement surface is an important factor that directly affects driving safety and must be considered when evaluating the road performance. In especially wet conditions, the skid resistance of the pavement surface decreases considerably, increasing the risk of accidents. Moreover, poor drainage can lead to hydroplaning. This study aimed to develop a prediction equation for the roughness coefficient—that is, an index of frictional resistance at the interface of the water flow and surface material—to estimate the thickness of the water film in advance to prevent human and material damage. METHODS : The roughness coefficient can be changed depending on the surface material and can be calculated using Manning's theory. Here, the water level (h), which is included in the cross-sectional area and wetted perimeter calculations, can be used to calculate the roughness coefficient by using the water film thickness measurements generated after simulating specific rainfall conditions. In this study, the pavement slope, drainage path length, and mean texture depth for each concrete surface type (non-tined, and tined surfaces with 25-mm and 16-mm spacings) were used as variables. A water film thickness scale was manufactured and used to measure the water film thickness by placing it vertically on top of the pavement surface along the length of the scale protrusion. Based on the measured water film thickness, the roughness coefficient could be back-calculated by applying Manning's formula. A regression analysis was then performed to develop a prediction equation for the roughness coefficient based on the water film thickness data using the water film thickness, mean texture depth, pavement slope, and drainage path length as independent variables. RESULTS : To calculate the roughness coefficient, the results of the water film thickness measurements using rainfall simulations demonstrated that the water film thickness increased as the rainfall intensity increased under N/T, T25, and T16 conditions. Moreover, the water film thickness decreased owing to the linear increase in drainage capacity as the mean texture depth and pavement slope increased, and the shorter the drainage path length, the faster the drainage, resulting in a low water film thickness. Based on the measured water film thickness data, the roughness coefficient was calculated, and it was evident that the roughness coefficient decreased as the rainfall intensity increased. Moreover, the higher the pavement slope and the shorter the drainage path length, the faster the drainage reduced the water film thickness and increased the roughness coefficient (which is an indicator of the friction resistance). It was also evident that as the mean texture depth increased, the drainage capacity increased, which also reduced the roughness coefficient. CONCLUSIONS : As the roughness coefficient of the concrete road surface changes based on the environmental factors, road geometry, and pavement surface characteristics, we developed a prediction equation for the concrete pavement roughness coefficient that considered these factors. To validate the proposed prediction equation, a sensitivity analysis was conducted using the water film thickness prediction equation from previous studies. Existing models have limitations on the impact of the pavement type and rainfall intensity and can be biased toward underestimation; in contrast, the proposed model demonstrated a high correlation between the calculated and measured values. The water film thickness was calculated based on the road design standards in Korea—in the order of normal, caution, and danger scenarios—by using the proposed concrete pavement roughness coefficient prediction model under rainy weather conditions. Specifically, because the normal and caution stages occur before the manifestation of hydroplaning, it should be possible to prevent damage before it leads to the danger stage if it is predicted and managed in advance.
        4,600원
        17.
        2024.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Environmental pollution has led to global warming, which threatens human life. In response, hydrogen is gaining attention as a next-generation energy source that does not emit carbon. Due to its explosive nature, special care must be taken in the safe storage and transportation of hydrogen. Among various storage methods, liquefied storage, which can reduce its volume to 1/800, is considered efficient. However, since its boiling point reaches -253°C, the design of an insulation system is essential. For the design of insulation systems applied to large containers, a membrane-type design is required, which necessitates the use of cryogenic adhesives. To evaluate whether the cryogenic adhesive is properly implemented, assessments such as tensile and shear tests are necessary. This study presents a methodology for shear evaluation. Conventional methods for shear evaluation of adhesives result in slippage, preventing proper assessment. Therefore, a method involving drilling holes in the gripper and pulling from the holes must be applied. Optimal design concerning the size and location of the holes is required, and this study derives optimal values based on finite element analysis. By conducting experiments based on the results of this study, it is expected that the risk of gripper damage will be minimized, allowing for accurate evaluation of the adhesive’s performance.
        4,000원
        18.
        2024.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Advancements in technology for large aircraft have led to the development of new materials for aviation. Traditional alloy-based components in aircraft, once prevalent, are now being replaced by composite materials that offer superior performance in terms of strength and operational limits. Notably, propellers have evolved from wood to composite materials, finding application in contemporary small aircraft. In this context, there is a need for research on the composite propellers of the 3-blade "W Company," based on the widely used Rotax 914 engine in South Korea. This study aims to investigate the changes in noise and thrust corresponding to variations in propeller blade angles and engine RPM, with the goal of selecting the optimal propeller pitch angle. Particularly, the "W Company's" propellers are durable and cost-effective, widely adopted in domestic aircraft. The research seeks to propose an effective method to minimize noise while maintaining the necessary thrust, contributing to the smooth operation of aircraft and promoting coexistence with local communities.
        4,000원
        19.
        2024.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        세계적인 환경 규제로 인해 마그네슘 합금과 같은 경량 소재에 대한 수요가 증가하고 있으며, 마그네슘 합금 소재의 다양한 산업계 적용을 위한 용접 및 접합 방식에 대한 연구도 지속적으로 수행되고 있다. 앞선 Part I 연구에서는 마그네슘 합금에 대한 파이버 레이저 Bead on Plate(BOP) 실험을 수행하여 맞대기 용접 조건의 확보를 위한 기초 연구를 수행하였으며, 본 연구에서는 Part I의 기초 BOP 실험에서 도출된 적합한 레이저 출력과 용접 속도를 바탕으로 두께 3mm의 AZ31B 마그네슘 합금에 대해 맞대기 용접을 시행하였고, 인장시험 및 경도시험을 수행한 후 기계 물성 데이터를 분석하였다. 분석 결과 레이저 출력 2.0 kW, 50 mm/s (Heat input)의 조건에서 항복강도 151.5 MPa, 인장강도 224.1 Mpa으로 우수한 인장, 항복강도를 얻을 수 있었다.
        4,000원
        20.
        2024.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In the past, aviation technology developed from wood to alloys to composite materials. Propellers have also evolved from wood to composite materials for modern small aircraft. In this context, research is needed on a three-blade composite propeller based on the Rotax 912 engine, which is widely used in Korea. In this study, the goal is to select the optimal propeller pitch angle by investigating noise changes according to changes in blade angle and engine 4000RPM of three types of three-blade propellers different from each propeller manufacturer. By comparing the noise of the three types of propellers most commonly used in Korea and suggesting the minimum noise blade angle for each propeller, we aim to help aircraft operators select propellers and resolve noise complaints around airfields.
        4,000원
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