Silicon carbide (SiC) has emerged as a promising material for next-generation power semiconductor materials, due to its high thermal conductivity and high critical electric field (~3 MV/cm) with a wide bandgap of 3.3 eV. This permits SiC devices to operate at lower on-resistance and higher breakdown voltage. However, to improve device performance, advanced research is still needed to reduce point defects in the SiC epitaxial layer. This work investigated the electrical characteristics and defect properties using DLTS analysis. Four deep level defects generated by the implantation process and during epitaxial layer growth were detected. Trap parameters such as energy level, capture-cross section, trap density were obtained from an Arrhenius plot. To investigate the impact of defects on the device, a 2D TCAD simulation was conducted using the same device structure, and the extracted defect parameters were added to confirm electrical characteristics. The degradation of device performance such as an increase in on-resistance by adding trap parameters was confirmed.

By developing molds and facilities to horizontally mold the functional part of the dry-cast concrete block, We intend to develop molds and a series of facilities to horizontally mold the functional part of the dry-cast concrete block to increase production per cycle while maintaining existing production methods and major facilities. In order to do so, CAE analysis is first required to develop molds and facilities for horizontally molding the functional part of the drycast concrete block in the horizontal direction. The procedure will be carried out by reviewing the validity of boundary conditions and physical properties, 3D modeling, grid generation, construction of analysis models, model validity, analysis according to frequency changes, and analysis according to physical properties. First, through the comparison of two-point support, three-point support, and two-point and three-point support in the constraint conditions, We would like to compare it with the actual molded product in the horizontal direction. But first of all, it is considered two-point support in the constraint conditions in this paper.

최근 이식에 강하고 도심 환경에서의 스트레스에 강한 저항성을 지니고 있으며 병해충이 많이 없는 것으로 알려진 대왕참나무가 가로수 및 조경수로 많이 식재되고 있다. 하지만 대왕참나무의 식재량이 증가하면서 일부 지역에서 해충 피해가 보고되고 있고 이들에 대한 관리 대책 마련이 시급해지고 있다. 따라서 본 연구는 대왕참나 무의 식재 환경에 따른 해충 발생 양상을 조사하기 위해 수행하였다. 2022년부터 2023년 동안 7~8월 중에 조사를 수행하였으며, 육안조사법과 고지 가위를 활용하여 줄기와 잎에서 해충의 종별 개체수를 조사하였다. 대왕참나 무의 식재 환경은 도로변과 공원으로 구분하였고, 서울, 성남, 춘천, 원주, 여수, 함안, 창원 지역을 대상으로 진행 하였다. 조사 결과 총 20과 34종 1,126개체가 관찰되었으며 그 중 가로수에서 15과 18종 699개체가 관찰되었고 공원 지역에서 17과 27종 427개체가 관찰되었다. 가로수에서 나비목과 노린재목 해충이 더 많았으며 공원에서는 딱정벌레목 해충이 더 많았다.

In this research, a new piston pinhole boring machine for simultaneous 3-axis machining using linear motor and tilting unit is developed. We propose a new method that combines the linear motor and tilting unit to overcome the limitations of existing techniques. By using the linear motor, we suggest oval machining of piston pin holes. The horizontal reciprocating motion of the linear motor allows for oval machining, creating horizontal or vertical ovals on the pin holes based on the spindle tool's rotation angle. For profile machining of piston pin holes, we propose the use of a tilting unit that converts servo motor motion into linear motion. The vertical motion of the tilting unit enables profile machining, allowing the spindle tool connected to it to translate vertically during spindle rotation and shape the pin holes. To ensure simultaneous oval and profile machining, we suggest channel synchronization, separating the oval and profile machining channels. Synchronizing these channels enables both oval and profile machining to be performed simultaneously on the pin holes. In summary, this research aims to develop a piston pinhole boring machine that effectively utilizes the linear motor and tilting unit for accurate and productive pin hole machining, achieving simultaneous 3-axis machining.

Noble metal precipitates are fission products that can be found as metallic alloys in used nuclear fuel. They do not exist homogenously inside the fuel pellets, but exists in grain boundaries in the form of immiscible particles. The first drawback that comes because they exist in grain boundaries is the degradation of mechanical integrity. The particles in the grain boundaries can be considered as defect n solid solution of uranium oxide pellets, and they can change the lattice volume. Therefore, it is known that it can cause stress corrosion cracking of fuel pellets. Furthermore, there is a negative effect from the perspective of used fuel management. However, they also have a positive effect on used fuel management. Since the noble metal has galvanic reduction effect, the particles serve as an oxidation inhibitor for uranium. There are many other effects regarding to the noble metal precipitates. However, in any case, quantifying the particles is important in order to quantitatively analyze these effects from the perspective of used fuel management. SCALE/TRITON code was applied to calculate the noble metal isotopes including Mo, Tc, Ru, Rh and Pd. In order to calculate the distribution inside the pin, the multiregion cell model was selected. In particular, a cylindrical geometry was used, and the pellet was divided into several layers. In addition, coolant and cladding surrounded the pellet. Finally, the radial distribution was evaluated using the computational code, along with neutron flux map.

In this paper, the pull-out characteristics of composite Z-pins with various groove shapes was investigated. The groove shape of composite Z-pins was made by applying temperature and pressure to the top and bottom of laminated composites inside the autoclave. Then, the dumbbell type of pull-out test specimen was made by applying adhesive bond. Six types of pull-out test specimens were fabricated by changing the groove length. Pull-out load and displacement sere observed for those specimens with different groove ratio. The results show that the maximum pull-out load of the grooved pin with grooved ratio 0.4 was increased up to 30.6% by comparing the plain pin. The grooved pin has a high pull-out resistance even after the fracture of the interface.

The molybdenum cup and molybdenum pin, which are the main materials of the molybdenum electrode used for the LCD BLU CCFL electrode, have not been developed in Japan and all of them are imported and used from Japan, is giving a competitive burden. In this research, to develop the manufacturing technology of molybdenum pin used for CCFL electrode of LCD BLU, development of linear processing technology, development of molybdenum wire surface treatment technology, development of wire cutting technology, production of molybdenum pin, design and fabrication of JIG and Fixture for inspection, molybdenum pin prototyping and analysis, and development of 100% molybdenum pin inspection technology. In this paper, especially, research on prototype manufacturing and CAE analysis is treated.

The molybdenum cup and molybdenum pin, which are the main materials of the molybdenum electrode used for the LCD BLU CCFL electrode, have not been developed in Japan and all of them are imported and used from Japan, is giving a competitive burden. In this research, the CCFL electrode of LCD BLU is used to develop the manufacturing technology of molybdenum pin. The development of linear processing technology is used to that. The development of molybdenum wire surface treatment technology is used to that. The development of wire cutting technology is ued to that. The design and fabrication of JIG and Fixture for inspection is used to that. The molybdenum pin prototyping and analysis is used to that and finally, the development of 100% molybdenum pin inspection technology is used to that. In this paper, especially, research on design technology of wire cutting is treated.

The molybdenum cup and molybdenum pin, which are the main materials of the molybdenum electrode used for the LCD BLU CCFL electrode, have not been developed in Japan and all of them are imported and used from Japan, is giving a competitive burden. In this research, to develop the manufacturing technology of molybdenum pin used for CCFL electrode of LCD BLU, development of linear processing technology, development of molybdenum wire surface treatment technology, development of wire cutting technology, production of molybdenum pin, design and fabrication of JIG and Fixture for inspection, molybdenum pin prototyping and analysis, and development of 100% molybdenum pin inspection technology. In this paper, especially, research on surface treatment technology of molybdenum wire is treated.

In this study, carbon fiber Z-pins were fabricated by applying the different manufacturing process, and pull out test was performed for the dumbbell type of test specimens. Carbon fiber Z pins with smooth surface(type I) and stepped surface(type II, type III) were fabricated by using autoclave. Carbon fiber Z-pins with stepped surface were manufacturing method, that is, mold forming and machining process. The experimantal results show that carbon fiber Z pins have superior pull-out characteristics to carbon steel Z-pins. Pull-out load and pull-out toughness of carbon fiber Z pins with stepped surface are larger than those of carbon fiber Z-pins with smooth surface. Pull-out load and pull out toughness of mold f ormed Z-pin are 31% and 218% larger than those of smooth surfaced Z-pins, respectively.

합성보에 휨모멘트가 작용하면, 콘크리트 슬래브의 아랫면과 강재보의 윗면은 각각 인장력과 압축력에 의하여 팽창과 수축을 한다. 필연적으로 두 부재의 사이에서는 미끄러지려고 하는 수평전단력이 작용하게 되며, 이에 저항할 수 있는 전단 연결재의 역할이 매우 중요하다. 이 연구에서는 화약의 폭발력을 사용하여 강재보의 플랜지에 전단연결재를 고정하는 방법을 개발하였다. 개발 고정방법의 구조성능을 검증하기 위하여 보-기둥 접합부 실험과 유한요소해석을 수행하였다. 실험 및 해석결과를 기반으로 판단했을 때, 개발된 접합방식을 통하여 충분한 연성 및 강도를 확보할 수 있을 것으로 판단된다.

The degree of interaction is a very important factor determining stiffness, strength and deflection performance in the composite beam. Because this synthesis is made through the shear connector, the structural performance of the shear connector is very important. In this study, the connection method was developed using the driving pin to solve the problem of conventional welding connection method. To verify the structural performance of the developed connection method, the push-out test was performed and analyzed against numerical analysis results. Based on the results of the analysis, it is deemed that the structural performance can be obtained by joining the shear connection in proposed method.

The genus Diadegma is a well known parasitoid group and some are known to have symbiotic virus, PDV. A novel IV was discovered from the calyx of D. fenestrale female. This virus was named as D. fenestrale Ichnovirus (DfIV). The encapsidated DfIV genome contains 65 circular DNA segments with an aggregate size of 247,191 bp. Based on BLAST analysis, a total of 120 ORFs were predicted as follows: rep; 48, cys-motif; 11, vinnexin; 10, vankyrin; 9, PRRP; 3 and other unassigned genes (39). These viral genes were expressed in lepidopteran hosts (Phthorimaea operculella and Plutella xylostella) after parasitization which means DfIV genome segments were integrated into lepidopteran hosts. This study was focused on this result. Based on gene expression profile, candidate promoter and integration motifs were selected and then, fused with eGFP as a reporter gene. Modified DfIV genome segment was ligated to a commercial containing f1 ori and Ampr gene to propagate in E. coli. We have named this fusion vector as pIN. The construction methodology of pIN and its application would be further discussed in detail.

원자력이용시설에서 발생한 작은 크기의 금속 조각들을 효과적으로 제염하는 스마트 장치를 개발하였다. 이 장치는 자성연 마재를 포함한 영역의 자속밀도를 연속적으로 변화시키는 방법과 초음파를 이용하는 다중 제염장치이다. 한편, 제염 효율을 높이기 위해 제염 장치가 제염 대상 전체에 작용하도록 장치들의 구성을 수정하였다. 개발된 장치들의 최적 작동조건을 도 출하여 샘플로 선정한 소형의 금속방사성페기물에 대하여 자기장과 초음파제염을 각각 15분간 실시하였다. 그 결과 제염계 수의 범위는18~56으로 크게 향상되었으며 제염 후 모든 샘플은 백그라운드(BKG)값 이하로 확인되었다.

A diamond-like carbon (DLC) film deposited on a WC disk was investigated to improve disk wear resistance for injection molding of zirconia optical ferrule. The deposition of DLC films was performed using the filtered vacuum arc ion plating (FV-AIP) system with a graphite target. The coating processing was controlled with different deposition times and the other conditions for coating, such as input power, working pressure, substrate temperature, gas flow, and bias voltage, were fixed. The coating layers of DLC were characterized using FE-SEM, AFM, and Raman spectrometry; the mechanical properties were investigated with a scratch tester and a nano-indenter. The friction coefficient of the DLC coated on the WC was obtained using a pin-on-disk, according to the ASTM G163-99. The thickness of DLC films coated for 20 min. and 60 min. was about 750 nm and 300 nm, respectively. The surface roughness of DLC films coated for 60 min. was 5.9 nm. The Raman spectrum revealed that the G peak of DLC film was composed of sp3 amorphous carbon bonds. The critical load (Lc) of DLC film obtained with the scratch tester was 14.6 N. The hardness and elastic modulus of DLC measured with the nano-indenter were 36.9 GPa and 585.5 GPa, respectively. The friction coefficient of DLC coated on WC decreased from 0.2 to 0.01. The wear property of DLC coated on WC was enhanced by a factor of 20.