The EV electric vehicle market is growing rapidly worldwide. Magnet fixing technology is important for mass production of driving motors, a key part of electric vehicles. The magnet fixing method was carried out by the PAM (Polyamide molding) method. This study conducted the injection of rotor core magnet PA of EV traction motor and is a study on the amount of rotor core deformation. In this study, the change in the outer diameter of the product after injection and the non-molding phenomenon were tested. An injection mold was made and the results and phenomena of product deformation types are discussed.

The need for lightweight yet strong materials is being demanded in all industries. Carbon fiber-reinforced plastic is a material with increased strength by attaching carbon fiber to plastic, and is widely used in the aerospace industry, ships, automobiles, and civil engineering based on its low density. Carbon-reinforced fiber plastic is a material widely used in parts and manufactured products, and structural analysis simulation is required during design, and application of actual material properties is necessary for accurate structural analysis simulation. In the case of carbon-reinforced fiber plastics, it is reported that there is a porosity of around 0.5% to 6%, and it is necessary to check the change in material properties according to the porosity and pore shape. It was confirmed by applying the method. It was confirmed that the change in elastic modulus according to the porosity was 10.7% different from the base material when the porosity was 6.0%, and the Poisson's ratio was confirmed to be less than 3.0%. It was confirmed that the elliptical spherical pore derived different material properties from the spherical pore depending on the pore shape, and it was confirmed that the shape of the pore had to be confirmed to derive equivalent material properties.

The effect of the stacking order of carbon fiber composites on impact damage was studied. The main form of damage was delamination starting at the interface between individual ply. The force-time response when the impact was applied was monitored and the energy absorbed by the panel was analyzed. The energy absorbed during interlayer separation was found to be affected by the stacking order, and the residual energy absorbed by peel propagation increased linearly as the total peel area increased. It was found that the compressive strength after impact was related to the maximum delamination area.

High-strength low-alloy steel is one of the widely used materials in onshore and offshore plant engineering. We investigated the alloying effect of solute atoms in α-Fe based alloy using ab initio calculations. Empirical equations were used to establish the effect of alloying on the Vicker’s hardness, screw energy coefficient, and edge dislocation energy coefficient of the steel. Screw and edge energy coefficients were improved by the addition of V and Cr solute atoms. In addition, the addition of trace quantities of V, Cr, and Mn enhanced abrasion resistance. Solute atoms and contents with excellent mechanical properties were selected and their thermal conductivity and thermal expansion behavior were investigated. The addition of Cr atom is expected to form alloys with low thermal conductivity and thermal expansion coefficient. This study provides a better understanding of the state-of-the-art research in low-alloy steel and can be used to guide researchers to explore and develop α-Fe based alloys with improved properties, that can be fabricated in smart and cost-effective manners.

국제적인 선박 배출 가스에 대한 환경 규제가 점차 강화됨에 따라 전기추진 및 하이브리드 추진선박에 대한 관심이 증대되고 있으며, 이러한 선박에 적용하기 위한 다양한 솔루션이 개발 및 적용되고 있는데 특히 전력계통의 안정화, 시스템의 효율성을 높이기 위 한 방안으로 직류배전시스템이 적용되고 있다. 또한, 선박용 직류배전시스템에 대한 안전 및 성능에 대한 검증 및 시험의 중요성이 요구 되고 있다. 본 연구는 직류배전 테스트베드 구축 및 직류배전(가변속 발전)시스템에 대한 성능을 검증하고 연료소모량 분석한 결과로서 선박용 직류배전에 적용되고 있는 가변속 발전시스템을 적용하였으며, 발전기에서 출력되는 전력을 정류기를 통해 직류전력으로 변환하 여 시스템에 연계하고 이러한 장치들을 감시 및 제어하기 위한 시스템을 개발하였다. 이러한 직류배전 시스템을 적용한 시험을 통해 최 대 전압은 751.5V이고 최소전압은 731.4V가 계측되어 전압변동률은 2.7%로 3% 이내에서 안정적으로 전압이 공급되는 것을 확인하였고 부 하변동에 따라 가변속 발전시스템을 적용하였을 경우 연료소모량이 기존 정속발전시스템과 비교하여 구간에 따라 최대 20%이상 연료절 감이 되는 것을 시험을 통해 확인하였다.

The air dilution olfactory method to measure complex odors needs to store and carry odor samples from the field sampling until the analysis in laboratories. Until the analysis of sample in the laboratory, odor dilution factor (odor sensitivity) in the sample bag may decrease over time depending on the characteristics of each odor substances. This is one of the limitation for the air dilution olfactory method. Thus, the air dilution device enable to measure without loss in complex odors of samples. Recently, many studies on the performance test of on-site air dilution devices, i.e., field olfactometer, has been conducted to figure out the feasibility of the field olfactometers. In this study, seven odor samples were collected from five odor emission source sites. And comparative analysis with the air dilution olfactory method was carried out to assess the field applicability of the olfactometer. As results, the performance of the field olfactometer used in this study is regared as the affordable method. The dilution factors from between two methods showed the similar values, indicating low values of standard deviations. In order to ensure the accuracy and precision of measurement data using the field olfactometer, methodology minimized variables (that may affect measurement) needs to establish.

Ethyl formate (EF) is a naturally occurring insecticidal compound and is used to control pests introduced from abroad, in quarantine, by a fumigation method. In particular, it is mainly used as a substitute for methyl bromide and is less toxic to humans and less harmful to plants. This study aimed to investigate the possible acute toxicity of EF to useful organisms, and how to reduce phytotoxicity in watermelon, zucchini, and oriental melon. After fumigation with EF for 2 h, the LC50 values for earthworms, honey bees, and silkworms were 39.9, 7.09, and 17.9 g m-3, respectively. The degree of susceptibility to EF was in the order of earthworms, silkworms, and honey bees based on the LC50 value, and EF fumigation induced stronger acute toxicity to honey bees. Phytotoxicity was observed in watermelon leaves treated with a concentration of 7.5 g m-3 EF, and when treated with a concentration of 10.0 g m-3, it was confirmed that the edges of watermelon leaves were charred and seemed to be damaged by acids. Zucchini and melon, and other cucurbits, showed strong damage to the leaves when treated with a concentration of 10 g m-3, and sodium silicate, at concentrations of 10% and 20%, was used to reduce phytotoxicity. Therefore, acute toxicity towards nontarget organisms and phytotoxicity during the fumigation of EF should be reduced for efficient agricultural pest control.

본 연구는 지강과 이규의 견문록에 나타난 19세기 말 일본과 미국의 화교를 분석 한 것이다. 1860년 중국인의 해외 이주가 합법화하면서 해외로 진출하는 중국인들이 증가하였다. 이들이 현지에서 겪는 차별과 학대의 상황이 출사대신의 견문록을 통해 청 정부에 전달되면서 해외 영사 파견과 공사관 설립에 대한 논의가 본격적으로 진 행되었다. 지강은 1868년 벌링게임 사절단으로 출국하여 구미를 견문한 내용을 초사 태서기라는 책으로, 이규는 1878년 필라델피아 박람회의 중국 대표로 참가한 경험을 바탕으로 환유지구신록을 펴냈다. 두 인물이 견문록에서 일본과 미국의 화교의 어려 운 상황을 널리 알린 것은 청 정부의 화교 보호 정책 수립에 중요한 자료가 되었다.

The purpose of this paper is to examine how late Joseon art scene interpreted and reflected the concept of “The four masters of Yuan dynasty (元四大家, from this out I’ll mark it as a Yuan-sadaega)” into landscape paintings during the late 18th to the first half of the 19th century. This study employs a comparative approach, analyzing paintings created during this period in Korea and China, particularly those featuring Yuan-sadaega, while also investigating written records. The understanding of the Yuan-sadaega and their paintings began through the early 17th century Gosi's painting manuals(顧氏畵譜). Through Heo Guseo (許九敍)'s works and literary records, It can be observed that the perception of Yuan sadaega's artworks and artistic aspects during at least the late 18th century was established within the art community. Notably, a distinct shift in the understanding of painters and the composition of Yuan-sadaega is observed in the trends of the late 18th and first half of the 19th century. In the late 18th century, the use of dwelling in the mountain(山居) image into landscapes in Yuan-sadaega compositions is evident, particularly in works by artists like Won Myeong-ung(元命雄) and Jeong Su-yeong(鄭遂榮). This trend is rooted in the contemporaneous significance of the art scene that produced a variety of paintings with the theme of ‘benevolence and daily life and in the shared understanding of the Yuan-sadaega as recluse(隱士) within the artistic community. This collective perception of the Yuan-sadaega seems to have been influenced by the influx of theories and writings on painting by Dong qi chang(董其昌) and by the circulation of painting manuals. The early 19th century, a new a new type of painting emerged alongside Bangjak(倣作, paintings of creative imitation) about the Yuan-sadaega, known as ‘Bangjak about Yuan dynasty painters(倣元人山水圖). Through the works of Kim Jeong-hee(金正喜) and Heo Ryeon(許鍊), it is noteworthy that various scenes are depicted under the same theme. This reflects the establishment of universal values and standards for literary painting within the art community. This process led to the term ‘Ni-hwang(倪黃, abbreviation of Ni zan and Hwang gong wang)’ emerging and the concept expanding under the term ‘Yuan-in’ (元人, the symbol of Yuan art scean). As a result, the desired artistic style pursued by the contemporary artistic community was encompassed under the universal concept of ‘Yuan-in,’ and ‘Bangjak about Yuan dynasty painters’ came to embody this comprehensive theme

The coda /s/ is the most extensively studied phonological segment in Hispanic dialectology and sociolinguistics. However, the coda /s/ in Peruvian Andean Spanish has received relatively little attention. This study examines the variation in syllables and word-final /s/ in the city of Cusco, Peru. The statistical analysis of 2400 tokens from 24 sociolinguistic interviews reveals that the Spanish of Cusco is located within the conservative dialects with the predominant use of the sibilant [s] and that coda /s/ weakening is conditioned by linguistic factors, such as word position and the following phonological context. Additionally, younger speakers and those who have higher levels of education weaken codal /s/ more frequently than older generations and speakers with lower levels of education.

The construction industry stands out for its higher incidence of accidents in comparison to other sectors. A causal analysis of the accidents is necessary for effective prevention. In this study, we propose a data-driven causal analysis to find significant factors of fatal construction accidents. We collected 14,318 cases of structured and text data of construction accidents from the Construction Safety Management Integrated Information (CSI). For the variables in the collected dataset, we first analyze their patterns and correlations with fatal construction accidents by statistical analysis. In addition, machine learning algorithms are employed to develop a classification model for fatal accidents. The integration of SHAP (SHapley Additive exPlanations) allows for the identification of root causes driving fatal incidents. As a result, the outcome reveals the significant factors and keywords wielding notable influence over fatal accidents within construction contexts.

본 연구는 중국 산시성(山西省)에 있는 대학 교수를 대상으로 교수의 그릿, 직무만족도, 교사효능감, 소통능력 간의 구조적 관계 분석을 목적 으로 한다. 연구 문제는 다음과 같다. 중국 대학교수의 그릿, 교사효능 감, 소통능력, 직무만족도의 수준은 어떠한가? 변수 간의 상관관계는 어 떠한가?, 중국 대학교수의 그릿, 교사효능감, 소통능력이 직무만족도에 미치는 직접적 영향은 어떠한가?, 중국 대학교수의 그릿과 직무만족도의 관계에서 교사효능감과 소통능력의 부분 매개효과는 어떠한가? 분석 결 과, 연구 변인 중에 그릿(M=3.288)의 평균이 가장 높은 수준이었으며 직 무만족(M=3.119), 교사효능감(M=3.102), 소통능력(M=3.042) 순서로 나타 났다. 변인 간의 상관관계 분석 결과에서는 중국 대학 교수들의 그릿, 교 사효능감, 소통능력 및 직무만족 간에 모두 유의미한 양(+)의 상관관계가 나타났다. 중국 대학 교수의 그릿은 교사효능감, 소통능력, 직무만족에 통계적으로 유의한 영향을 미치는 것으로 나타났다. 또한 그릿은 교사효 능감과 소통능력을 통해 직무만족에 간접적으로 영향을 미치는 것으로 확인되었다. 연구 결과를 바탕으로, 대학교수의 그릿을 향상시키는 교육 및 훈련 프로그램이 개발되고 실행될 필요가 있다는 것을 제안하였다. 이는 교수들의 교수 효능감과 소통능력을 높이는 데 도움이 되어, 결국 직무만족도의 향상에 기여할 것으로 보기 때문이다.

유역 내 산림은 생태계 유지에 있어 중요한 역할을 맡고 있으며 생태네트워크 체계를 구성하는 주요 기반 환경이다. 그러나 지난 수십여 년간 행해진 무분별한 개발사업으로 인해 산림 파편화 및 토지이용 변화가 가속화되었으며 본래의 기능을 상실하게 되었다. 산림 생태계를 파악하는 데 있어 산림의 구조적 패턴은 생태적 과정과 기능에 직접적인 영향을 미치기 때문에 변화패턴을 파악하고 분석하는 것은 중요한 인자라 할 수 있다. 이에 본 연구는 금강 상류 댐 유역을 대상으로 FRAGSTATS 모델을 통해 시계열적인 토지피복변화에 따른 산림 경관의 구조적 변화를 분석하였다. 토지피복 변화탐지를 통한 금강 상류 댐 유역 내 토지피복변화는 1980년대부터 2010년대까지 산림 33.12㎢(0.62%), 시가화건조지역 67.26㎢ (1.26%) 증가하였고 농업지역 148.25㎢(2.79%) 감소하였다. 유역 내 산림 경관분석결과 No sampling 분석에서는 경관백분 율(PLAND), 면적가중근접지수(CONTIG_AM), 평균 중심지 면적(CORE_MN), 인접지수(PLADJ)가 증가하였고 패치 수(NP), 경관형태지수(LSI), 응집지수(COHESION)가 감소하였다. Moving window 분석을 통해 구조적 변화패턴을 파악한 결과, 경상북도 상주시, 충청북도 보은군, 전라북도 진안군 내 산림 경관은 상대적으로 잘 보전되어 있었으나 충청북도 옥천군, 영동군 그리고 충청남도 금산군 사이의 경계부와 전라북도 무주군과 장수군 인접 지역의 산림 경관에서는 파편화가 진행되고 있었다. 결과를 토대로 추후 해당 지역의 산림 관리전략 수립 시 파편화 지역을 대상으로 조림사업을 수립할 필요가 있을 것으로 사료된다. 본 연구를 통해 산림 경관의 파편화가 예상되는 지역을 도출할 수 있었으며, 유역 산림의 건전성 평가 및 관리계획 수립을 위한 기초자료로써 활용될 가능성을 기대할 수 있다.

Recently, it has been applied and used in various fields using 3D printing. Since it is closely connected to our lives, the mechanical properties of the output are actively studied. Therefore, in this study, tensile specimens were manufactured using the FDM lamination method using PLA materials, and the changes in tensile properties were compared and evaluated. First, 120 tensile specimens were manufactured using the spacing angle and lamination density of the lamination angle as control factors. After that, a tensile test was conducted at the same tensile speed of 5mm/s to compare and evaluate the tensile strength and elastic modulus. As a result, it was found that the tensile strength and elastic modulus increased linearly with density than the lamination angle. In addition, when the laminating angle was 0°, the tensile strength and elastic modulus were the largest. When the laminating angle was 108°, the lowest tensile strength and elastic modulus were confirmed.