The curb weight of electric trucks is more than 10% higher than that of conventional internal combustion engine trucks due to the motor and battery. For this reason, cargo box developed for small electric trucks is required weight reduction, and cargo door that can reduce weight and maintain strength are being developed. In this paper, we designed the lightweight cargo door, confirmed the stability of the door through structural analysis, and developed a cargo box door that was more than 25% lighter by applying composite materials such as Sheet Molding Compound(SMC) and Fiber Reinforced Plastic(FRP).

This paper proposes a standardized vehicle body repair manual for vehicles with major damage to the rear side members caused by rear-end collisions. The manual is used to refine the vehicles. Typical work involves replacing large traffic accident modes with new members or modifying and aligning existing members. If repairs are made for various reasons, the members should be attached based on the body of a new vehicle. Unlike new vehicle members, the accident vehicle repair process depends heavily on the operator's skilled skills (i.e., the performance, purpose, level, and quality of the body replacement work due to the nature of the vehicle body replacement work). When repairing or replacing a rear side member of a body repair, three methods of operation are applied because the damage and deformation vary depending on the object of the other party, although the degree of damage varies. There is no standardized manual for side member over-hole replacement, partial replacement, or partial modification, since these repair methods vary depending on the operator's thoughts and angle of view. Therefore, customers should use standardized vehicle repair manuals to ensure that their vehicle receives the same repair when damaged. This study is expected to develop a standardized vehicle repair manual to reduce the drop in used market prices after replacement or repair of rear side members at vehicle repair plants.

Car accidents require continuous access to new technologies in the field of maintenance that cannot be achieved by textbook theory alone due to the nature of body repair without the same damage and repair conditions. In the case of vehicle repairs due to unexpected accidents, it is difficult to satisfy the needs of the vehicle owner, so in this study, it is possible to restore them to their original state with improved technology like the vehicle owner. Better maintenance technologies have been explored: complete replacement of side quarter panels, partial replacement and partial modification of side quarter panels, as well as tangible and intangible effects such as not applying depreciation rates due to traffic accidents, preventing environmental pollution and maximizing owner satisfaction.

홀로그램 이미지를 표시할 수 있는 자동차 리어 램프를 제작했다. 홀로그램은 노광할 때 물체 광은 0도, 참조 광은 60도가 되게 광학계를 설계해 투과 타입으로 제작했다. 홀로그램과 광원을 일체형으로 하면서 두께 30mm의 콤팩트 한 재생 장치를 제작했다. 홀로그램 크기는 200×100mm로 제작했다. 에지릿 홀로그램으로 콤팩트 한 재생 장치에 적 용하기 적합했다. 리어 램프는 미등, 정지등, 방향지시등, 후진등과 홀로그램 재생 장치를 포함 시켜 아크릴로 제작했 다. 리어 램프의 외관은 홀로그램 이미지의 의도와 연결되게 배트맨 모양으로 디자인했다. 에지릿 홀로그램을 이용한 콤팩트 한 재생 장치는 리어 램프의 기능과 연계해 사용하기에 적합하다는 것을 확인하였다.

The rear door of the wheeled armored vehicle is a part that provides a passage for the crew to get on and off when it is opened and plays a role in forming watertightness and airtightness when it is closed. A case where the rear door was deformed during the rear door opening/closing operation occurred. The rear door should be improved because when it has been deformed, it is impossible to form watertight and positive pressure so that damage for humans and repair cost may occur. Therefore, in this paper, the causes of deformation were analyzed, and improvement plans were derived in order to prevent the deformation of the rear door of wheeled armored vehicles. In addition, a verification test was conducted to evaluate the appropriateness of the improvement plans.

In this study, a mixed resin containing Bis-GMA was developed to produce a light-emitting sign using quantum dots. As a result of measuring the viscosity, color coordinates change, and luminance of the mixed resin, the following conclusions were obtained. The viscosity of the mixed resin decreased as the content of the diluent increased, and viscosity values ​​ranged from 3,627 to 1,349cps showed as a result. The viscosity of the mixed resin decreased as the temperature increased, and the viscosity showed a value of 5,156 to 1,132cps. For the optical properties of InP/GaP/ZnSe/ZnS quantum dots, the absolute quantum efficiency was 91% at 522nm and 90% at 618nm when the gallium was 0.01%. The luminance of the light-emitting sign using the resin mixed with quantum dots was showed 142.6cd/m2 in white and 104.2cd/m2 in the red region.

In order to develop a 1 ton truck rear wheel air suspension module, this study designed and manufactured a Z-type spring and air suspension module test jig to optimize the design and reliability of the Z-type spring and vibration-free air suspension module, which are core parts, and to secure the reliability of the developed parts. We were able to achieve the technology development goal of this thesis by making a prototype and conducting a test evaluation at an external test and research institute to perform the vibration endurance test aimed in this study.

This study investigated the effect of the addition of various levels of pig head meat (HM) as a substitute for rear leg meat (RLM) on the physico-chemical quality characteristics of non-emulsified, smoked, and cooked sausage during refrigerated storage. Sausages were prepared in four variations according to the proportion (0%, 10%, 20%, or 30%) of HM added and maintained at 4°C. Quality measurements were taken for 28 days. The sausages added with the addition of 20% and 30% HM had significantly (p<0.05) higher moisture and lower protein content compared to those without the addition of HM. The pH value during the storage period was higher (p<0.05) in the sausages to which the HM had been added than in those without HM. The sausages with 30% HM showed the lowest (p<0.05) L* and b* values and the highest (p<0.05) a* value during the storage period. The 2-thiobarbituric acid reactive substances (TBARS) content, hardness, cohesiveness, springiness, gumminess, and chewiness of the sausages showed no significant variations with the addition of various levels of HM. These data suggest that RLM could be substituted with 30% HM because it does not negatively affect the quality of the non-emulsified sausage. However, a further study on sausages made with 100% HM instead of RLM may be needed to improve its utilization.

This study was performed to analyze the effect on driving performance by identifying the flow characteristics of the rear diffuser such as drag coefficient, lift coefficient, velocity vector, velocity streamlines, turbulence kinetic energy and vortex-core region according to the angle of the sedan rear diffuser and the shape of the divider. The angle of the diffuser was analyzed at 2° intervals from 0° to 18°, and the divider was analyzed by changing from one to five. The three-dimensional modeling was performed using CATIA V5 and the vehicle model was selected as a sedan car in the form of an LF Sonata. The CFD analysis was performed in order to identify the flow characteristics of rear diffuser using ANSYS CFX 14.5.7. For each model, the analysis was performed under each condition with speeds of 80km/h, 100km/h, 120km/h, 140km/h. The results of the flow analysis showed that the rear diffuser angle was the best result in driving stability at 6°. The results of the study on the number of dividers showed the best result value in driving stability when the rear diffuser angle was 6° and the divider was 3 and selected as the optimal shape.

본 논문에서는 CR 쉘 요소 해석 기법을 활용하여 모터사이클 후방프레임의 해석을 수행하였다. CR 쉘 요소 해석기법은 적은 요소 수에서 NASTRAN보다 빠르게 수렴하는 결과를 보여주었다. 후방프레임은 수직 방향에 대해 실 주행 조건 시 엔진 RPM과 근접한 고유진동수를 가짐을 보여주었다. 2가지 설계변수를 반영한 세 가지 경우에 대한 해석이 제시되었으며, 보강용 자재는 동일한 중량 변화 내에서 두께 변화에 비해 더 유용한 수단임을 확인할 수 있었다. 본 연구의 구조 해석은 차후 모터사이클 후방프레임의 내구성을 향상하는 설계 개선 연구에 효과적으로 활용될 수 있다.

In this paper, we investigated the effect of the passivation stack with Al2O3, hydrogenated silicon nitride (SiNx:H) stack and Al2O3, silicon oxynitride (SiONx) stack in the n type bifacial solar cell on monocrystalline silicon. SiNx:H and SiONx films were deposited by plasma enhanced chemical vapor deposition on the Al2O3 thin film deposited by thermal atomic layer deposition. We focus on passivation properties of the two stack structure after laser ablation process in order to improve bifaciality of the cell. Our results showed SiNx:H with Al2O3 stack is 10 mV higher in implied open circuit voltage and 60 μs higher in minority carrier lifetime than SiONx with Al2O3 stack at Ni silicide formation temperature for 1.8% open area ratio. This can be explained by hydrogen passivation at the Al2O3/Si interface and Al2O3 layer of laser damaged area during annealing.

PURPOSES: In this study, a method of maximizing visibility by effectively installing rear reflectors on freight cars was analyzed to reduce traffic accidents caused by poor visibility of trucks at night. METHODS: Comparisons were made when a (1) rear reflector, (2) rear reflector and line contour, and (3) rear reflector and full contour were installed in a truck using virtual driving simulation. The safety level of each installation method was quantitatively analyzed by selecting the cognitive distance, safe distance maintenance, and deceleration in the case of using stone embankment as an effective safety measure. RESULTS : When the rear reflector and full contour was installed, the cognitive range was the longest, and the safety distance could be maintained for a relatively long time. In addition, it was possible to stop or avoid a collision when a sudden event occurred. CONCLUSIONS: The severity of rear-end crash with freight cars is very high at night, mostly because drivers are unaware of the freight car ahead. Accidents can be prevented if drivers can recognize cargo trucks. Based on the results of this study, the installation of a truck's rear reflector and full contour system will enhance night visibility, and the number of traffic accidents will also decrease.

후방가장자리 개체군은 전형적으로 고도의 고립된 분포에 따라 개체군의 유전적다양성이 낮고 절멸의 위험이 높다고 평가한다. 그러나 유전적다양성이 낮음에도 불구하고 오랜 기간에 걸쳐 개체군의 지속이 관찰된다. 따라서 개체군의 지속에 관여하는 생태적인 과정에 대한 이해가 필요하다. 넓은잎제비꽃은 세계적인 분포에서 한국이 후방가장자리개체군에 해당한다. 한반도의 중부 내륙에 제한적인 분포를 나타내는 넓은잎제비꽃의 지속에 관여하는 요인을 알아보기 위해 먼저 분포현황을 조사하였다. 다음으로 식생 및 토양환경, 식물계절학, 자가화합성 여부, 개체군 구조 그리고 분포지에서 관찰되는 위협요인을 조사하고 평가하였다. 넓은잎제비꽃은 석회암지대의 낙엽활엽수림 하부, 낙엽침엽수와 낙엽활엽수 식재림의 하부, 관목림의 하부 그리고 초원에 걸쳐 분포하였다. 개체군내에서 유묘의 재정착이 관찰되었고 대부분 안정적인 개체군 구조로 나타났다. 개방화는 화분매개곤충의 방문이 열매의 생산과 밀접한 연관이 있었다. 그렇지만 개체군 내에서 폐쇄화의 생산이 보다 왕성하였고 일부 개체군에서는 개체의 크기가 큼에도 불구하고 폐쇄화만을 생산하였다. 개체의 크기는 개방화의 생산에 비해 폐쇄화의 생산에 보다 더 높은 상관이 있었다. 따라서 개체군내의 유묘 보충은 폐쇄화의 기여도가 높은 것으로 판단되었다. 개방화와 폐쇄화의 생산은 토양분석 항목 중 유효인산을 제외하고는 상관이 없는 것으로 나타났다. 넓은잎제비꽃은 자가불화합성으로 이것은 왕성한 폐쇄화의 생산능력이 존재하기 때문으로 생각되었다. 생육지에서 관찰된 잠재적인 위협요인으로는 석회암광산 의 개발, 경작지의 확대 및 주택의 건설이 있었다. 넓은잎제비꽃은 한반도에서 석회암지대에 고립되어 분포하지만 초원부터 비교적 울폐도가 낮은 식생하부에 이르기까지 넓은 식생환경에 걸쳐 관찰되었다. 또한 다수의 개체군과 안정적인 개체군 구조를 유지하고 있어 현재와 같은 상태가 유지된다면 개체군의 지속은 가능할 것으로 평가되었다.

According to the automobile industry has been developing day by day, traffic accidents are increasing and the rear-end collision is the second largest of the entire collision. Due to the high social cost caused by rear-end collision, several studies are in progress at home and abroad. Previous studies have shown that neck injury caused by rear-end collisions can be prevented by seat conditions. In this study, to find the condition that reduces neck injury, change of neck injury in rear-end collision is analyzed according to headrest height, seatback angle, and seatback torque using BioRID II dummy model and passenger behavior analysis program MADYMO. Therefore, it is expected that the condition of each variable to reduce the risk of injury to the neck can be applied to the seat design, which will reduce the injury and the social cost caused by the rear-end collision.

Both theoretical and experimental investigations were conducted to analyze defrosting behavior of a window heater operating in the low outdoor temperature(-20℃). To achieve this purpose, first a warm-chamber experiment(23℃) were performed to measure inner and outer surface temperature of the rear window as functions of both time and position. Secondly, a cold chamber experiment was made to continuously record defrosting process of the frosted window. Therefore this study was carried out to presume for mutual relation of analysis condition to get the optimum temperature distribution by three-way layout. The results shown that coefficient of determination has a fine reliability over 99.77%, 99.85% and temperature distribution is made by three-way layout.

The diffuser is effective in closed systems, however, its effect is weaken in open or free flow situations. This can be solved by modifying the rear-end of the diffuser in a manner that enables the formation of strong vortex. By doing that, a large portion of fluid's energy is converted to vortex's dynamic energy, which results in the deduction of static component, or in other words, the decrease of pressure. This study involved the design of rear-end part for efficient hydrodynamic performance of shroud diffusers, and demonstrated with numerical simulation by computational fluid dynamics (CFD). This study focuses on the use of brim end for the shroud where the effect of brim's length and attaching angle are analyzed.