Halictidae 전 세계적으로 3,500종 이상 발견된 큰 그룹이며 사람들의 땀에 이끌리는 특성을 보여 Sweat bee라는 이름으로 불린다. 이번 연 구에서는 꼬마꽃벌과에 속하는 Halictus hedini hedini Blüthgen, 1934을 한국에서 처음으로 보고한다. 본 종의 기재, 분포정보, 그리고 삽화를 제공 한다.
개나무좀과 (Bostrichidae)에 속하는 Lyctoxylon dentatum (Pascoe, 1866)(가슴각진개나무좀; 신칭), Melalgus batillus (Lesne, 1902)(큰머 리개나무좀; 신칭)을 채집하여 한반도에서 처음으로 보고한다. 본 연구는 이들에 대한 간단한 진단형질과 종 정보 및 사진자료를 제공하고자 한다.
The purpose of this study is to develop the protection of passengers in the event of a side collision with a school bus for children. Rub-rail is installed in the United States and other countries to protect the side of school buses for children to some extent. However, in the case of Korea, there are no safety devices to protect the side of school buses for children. Therefore, the FE model was analyzed to see if there is a difference depending on whether or not Rub-rail installed on school buses in the United States is applied, and whether it affects the damage to the human body. As a result, the maximum amount of intrusion at the point of collision differs depending on whether Rub-Rail is installed. It is expected that the evaluation results of IIHS for Rub-Rail may vary depending on the degree of intrusion.
With the mandatory implementation of ESC for trucks starting in 2023, domestic truck manufacturers in South Korea are advocating for a relaxation of the maximum safe slope angle to achieve cost savings. However, there is a lack of research on the dynamic safety of trucks based on ESC installation and the relaxation of the maximum safe slope angle. This study evaluates the relationship between static safety factor (SSF) and the maximum safe slope angle, analyzing the dynamic stability of trucks through simulation considering various experimental variables. The results quantitatively demonstrate the impact of relaxing the maximum safe slope angle on dynamic safety and provide recommendations for future safety regulations.
2015년부터 2022년도까지 6개목(딱정벌레목, 노린재목, 나비목, 벌목, 파리목, 총채벌레목) 곤충들에 대해서 식물검역현장 검출실적과 국내 보고된 미기록종을 분석하였다. 해당기간 동안 국경검역에서 6개목 곤충은 총 45,084건이 검출되었다. 같은 기간 국내에서는 총 545종이 미기록종 으로 보고되었으며, 이중 9종은 국경검역에서도 검출된 것으로 확인되었다. 검역현장에서는 딱정벌레목, 총채벌레목, 노린재목이 높은 검출률을 보 였으며, 국내 미기록종 중에서는 벌목이 176종으로 가장 많이 보고되었다. 본 연구를 통해 침입압력(국경검역 검출)과 실제 침입(국내 미기록종 발 견) 사이에 비동시성이 확인되었다. 향후 보다 장기적인 분석이 필요할 뿐만 아니라 지속적인 식물검역시스템 개선이 필요할 것으로 판단된다.
This study examines the persistent decline of the motorcycle industry despite governmental interventions, using the perspective of path dependency. Drawing from W. B. Arthur's concept of 'Lock-in by insignificant historical events', the research delves into the lock-in phenomena within the industry's life cycle. We identified path dependency lock-in categories: contingency, historicity, and technological lock-in. The industry's licensing production method during its embryonic phase led to limited technological capabilities, establishing a technological path dependency. During the currency crisis and in alignment with China's open-door policy, the industry chose to import cheaper components, opting for economies of scale over technological innovation, intensifying the lock-in. Furthermore, the classification of motorcycle as a free industry before the currency crisis resulted in a lack of governmental support. This neglect has continued, with even modern electric motorcycle facing regulation. In conclusion, to overcome this entrenched path dependency and lock-in, significant governmental policy restructuring is essential.
In the context of the 4th Industrial Revolution, the rise of electric vehicles and personal mobility is evident. However, regulatory authorities seem to overlook vast opportunities, placing two-wheelers in a deregulated category and focusing mainly on regulations. This paper addresses a notable trend in e-mobility, emphasizing aspects often overlooked in traditional motorcycle regulatory research. Using the industrial life cycle theory as a basis, we identify challenges that have affected traditional combustion-engine two-wheelers and offer insights to navigate similar obstacles in the future. Consequently, the domestic two-wheeler market experienced a brief surge but lacked sustainable growth prospects. However, considering Japan's success in establishing global standards and design dominance in the two-wheeler industry despite its late entry, there appears to be potential for a rebound in the domestic market.
호박꽃과실파리(Z. scutellata)는 박과작물에 피해를 주는 중요한 해충이다. 현재 큐루어(Cuelure)는 국내에서 검역 대상 해충으로 규정된 오이과실파리, 타우과실파리, 및 퀸슬랜드과실파리와 더불어 호박꽃과실파리 수컷 성충의 예찰에 다양한 제형으로 활용되고 있다. 본 연구는 액 체, 고체, 및 왁스제형의 큐루어에 대한 호박꽃과실파리 수컷 성충의 야외 유인효과를 검증하기 위한 것으로 2021년 4월부터 10월까지 제주 2개 지역과 경북 1개 조사에서 2주 간격으로 모니터링하였다. 호박꽃과실파리의 발생밀도가 높은 제주지역에서는 7월부터 8월에 액체와 왁스제형의 큐루어에 호박꽃과실파리가 더 많이 유인되어 통계적인 유의차가 있었으나, 호박꽃과실파리의 발생밀도가 낮은 경북지역에서는 제형별 유인력 에 차이가 없었다. 야외조사 결과를 바탕으로 액체와 왁스제형의 큐루어가 호박꽃과실파리 수컷 성충 예찰에 권장되며, 이 두 제형의 큐루어에 유 인되는 검역 대상 과실파리류의 국내 예찰에 효과적일 수 있다.
We propose a method for developing an in-pipe inspection robot based on multiple inertial sensors. Estimating the position of underground pipelines where satellite signals do not reach remains challenging. High-precision inertial sensors and high-tech mobile robots can be solutions, but their high price limits their general use. We developed an in-pipe inspection robot by combining various low-cost sensors with a microcomputer-based RC car platform. First, we fabricated a multi-inertial sensors module by combining commercial grade low-cost MEMS inertial sensors. The sensor values measured by the multi-inertial sensor are transmitted to the main computer through the MCU, and the attitude angle of the vehicle is finally calculated through the inverse variance weighted average. The travel distance of the robot is estimated by using hall sensors and neodymium magnets attached to the inside of the wheels. Also, we measured the pipe diameter using multiple ultrasonic sensors. We verified the estimation accuracy of each sensor through experiments and consequently estimated the 3D trajectory of the in-pipe robot.
The purpose of this study was to develop a side protection device for school buses for children. In the case of the door side impact beam, it plays a very important role because it protects passengers from external collisions. However, in the case of a school bus for children, the space between the door and the door trim is very narrow, unlike a general passenger car. So, as an alternative to this, we are trying to develop Rub Rail, which is compulsory for children's school buses in the United States. Based on the results of structural analysis according to the cross-sectional shape of the rub rail, we want to find out the appropriate shape of the rub rail.
In this paper, we propose a dynamic stability prediction method for heavy vehicles based on Lateral Load Transfer Ratio. The key factors influencing vehicle roll motion are the vehicle's load, the position of the center of mass, the tread and the vehicle speed. Using these factors, we derive the lateral load transfer ratio (LTR) formula. In addition, we investigated LTR changes and vehicle rollover of heavy vehicles in various scenarios using TruckSim. As a result, the threshold value of the change rate of the LTR at which the vehicle rolls over was 0.68-0.72. Finally, we performed a numerical experiment to prevent rollover by calculating the optimal speed in the rollover situation.
In this study, corrosion fatigue crack propagation was investigated in pH buffer environment using the giga strength steel and its heat-affected zone, and the results were compared with theoretical model prediction. Also, the pure corrosion effect on fatigue crack propagation in a corrosive environment was compared with the modified Forman equation. As results, the average value of corrosion rate obtained as the ratio of the net corrosion-induced crack length to the total crack length under cyclic loading in the base metal and heat-affected zone under experimental loading conditions. These results exhibit a new theoretical method for corrosion fatigue crack propagation that predicts a purely corrosion effect on the behavior to be determined.
In this paper, a simulation computerized crash analysis evaluation method through reverse engineering was applied to the Defender vehicle to systemize and simplify the certification of small-scale electric vehicles. The Defender vehicle was selected as a benchmarking vehicle that converts into an electric vehicle, and the layout of the frame and element analysis of individual parts were conducted through reverse engineering. To review the vehicle package layout, the fastening and assembly method for each part was analyzed referring to the Defender maintenance guide and parts list, and it was used for frame element technology analysis. In addition, collisions according to the main frame material and the shape of the crash box were analyzed, and various cases were analyzed through parameter study. As a result of the crash analysis, it was found that the mild steel main frame could not guarantee the safety of the vehicle in a fixed wall collision situation, and the ATOS material would increase the collision safety of the Defender relatively. Through the crash analysis according to the shape of the crash box, it was found that the strength of the crash box is too high compared to the main body, and this should be reflected in the design for small-volume production of multiple products.
This research propose a vehicle attitude estimation method using sensor fusion of speedometer and six-axis inertial sensor. External acceleration generated in a dynamic environment such as high-speed movement of a vehicle causes a considerable error in the attitude angle measured by the accelerometer. The external acceleration is estimated using velocity data obtained from speedometers mounted on most vehicles. The vehicle velocity is decomposed into three vector components using the angular velocity and attitude angle measured by the inertial sensor in the previous time step. The attitude angle estimated by the speedometer and the accelerometer is used to correct the error of the gyro sensor in the Kalman filter. In order to verify the performance of the proposed algorithm, experiments on a scenario of rapid acceleration/deceleration of a truck in a straight section and a scenario of high-speed driving on a long-distance highway are conducted.
In this research, a capacitance pressure sensor with graphene membrane and titanium substrate have been developed and studied as a potential robust substrate and a sensitive membrane material for micromachined devices. Mechanical lamination process combined with micromachining processes have been selected for the fabrication of the pressure sensor. Prior to the fabrication, capacitive pressure sensors based on a graphene diaphragm and titanium substrate have been designed. The fabricated pressure sensor uses a titanium substrate, a graphene film laminated with a floating movable plate, and a fixed surface micromachined back electrode of electroplated nickel. Finite element method is adopted to investigate the residual stresses formed in the process.Also, the out-of-plane strain is calculated under the pressure of the diaphragm. The sensitivity of devices manufactured using these techniques is 7.5 to 4 kPa-1, and the net capacitance change in the range of 0 to 180 kPa is 013 pF.
벌목 개미과 시베리아개미아과(Hymenoptera: Formicidae: Dolichoderinae)의 Linepithema humile (Mayr, 1868) (신칭 민개미)가 국내에서 처음 발견되었다. 진단학적 형질, 분포 범위, 해충으로서의 잠재적 가능성에 대하여 논의되었다.
수입되는 서양뒤영벌과 그에 대한 화분매개 대체안들을 비교 평가하기 위해 증분이익을 추정하여 분석하였다. 분석결과, 판매수익에서 공통 생산원가를 차감한 증분수익은 인공수분을 사용할 때보다 화분매개곤충을 사용할 때 더 많았으며, 증분원가는 수입산 서양뒤영벌이나 꿀벌을 사용할 때보다 국내산 서양뒤영벌이나 인공수분을 사용할 때 더 적었다. 각 대안별 증분이익을 살펴보면, 수입산 서양뒤영벌 46,801 백만원, 국내산 서양뒤영벌 47,170 백만원, 꿀벌 46,975 백만원, 인공수분 29,839 백만원 이었다. 증분이익은 각 대안을 선택했을 경우 얻을 수 있는 회계적 이윤을 의미한다. 다만, 회계적 이윤 전부를 화분매개 대안이 기여한 것으로 볼 수 없으며, 귀속지대나 정상이윤과 같은 잠재적 비용이 포함되어 있다. 잠재적 비용에 해당하는 기회원가를 고려할 때, 수입산 서양뒤영벌을 사용하는 대안은 경제적 손실이 발생하는 것으로 나타났다. 이는 과수⋅작물 생산농가가 수입산 서양뒤영벌을 사용하는 대신 다른 대체안을 선택할 경우 추가적인 경제적 이윤을 창출할 수 있음을 의미한다.
For the automotive application, graphene-glass composites were fabricated using E-glass fiber(GF) coated with various types of graphene nanosheets deposited by electrophoretic deposition. Graphene oxide(GO) was first synthesized using a modified Hummer’s method and its subsequent ultrasonic treatment in deionized water produced a stable stop of the GO. Glass fiber was immersed in water and GO suspension near the copper anode. The potential applied between the electrodes caused the GO to move toward the anode. In addition, the GO coated yarn was exposed to hydrazine hydrate at 100℃ to obtain a reduced graphene oxide(rGO) coating yarn. Both GO and rGO coated glass fiber yarns were used to fabricate unidirectional epoxy-based multi-scale composites by passive lay-up. The presence of a conductive rGO coating on glass fiber improves both the electrical conductivity and thermal conductivity of the composite. In addition, rGO-based epoxy-glass composites have been used to improve the dielectric constant, providing the option of using this structure for electromagnetic interference shielding.