• The Plant Pathology Journal
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• 제17권6호
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• pp.354-356
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• 2001

In August 2001, pod rot of cowpea caused by Choanephora cucurbitarum was found in the experimental fields of the Gyeongsangnam-do Agricultural Research and Extension Services, Korea. Initial symptoms of the disease were the appearance of water-soaked, dark-green lesions and followed by rapid rotting of the infected tissues. As the disease progressed, whitish mycelia and monosporous sporangiophore with monosporous sporangiola were produced on the lesions. The fungus produced white to pale yellowish brown mycelia with scattered monosporous sporangiophore and monosporous sporangia containing sporangiospores on potato dextrose agar (PDA). Monosporous sporangiophore was long, slender and branched at the apex, with each branch bearing a sporangiospore. Sporangium was subglobose in shape and 42.6-112.6 ㎛ in size. Monosporous sporangiola were elliptic, fusiform or ovoid, brown in color, and 9.8-23.4$\times$7.2-12.8 ㎛ in size. Sporangiospores were elliptic, fusiform or ovoid in shape, dark brown or brown in color, 12.9-24.6$\times$8.6-15.4 ㎛ in size, and had three or more appendages. Zygospores were black and 43.6-72.4 ㎛ in size. The fungus grew on PDA at 15-40$\^{C}$, and optimum temperature was 30$\^{C}$. This is the first report on pod rot of cowpea caused by C. cucurbitarum in Korea.

• 항공우주산업기술동향
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• 제7권1호
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• pp.97-104
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• 2009

위성이 궤도에서 성공적인 임무수행을 하기 위해서는 위성시스템에 손상이 없도록 발사체로부터 분리되어야 하며 태양전지판과 안테나와 같은 부속장치의 전개를 성공적으로 수행하여야 한다. 이를 위해 분리장치가 사용되며, 특히 분리 시의 충격(500g이하) 및 오염이 적은 비폭발식 분리장치가 널리 쓰이고 있다. 본 논문에서는 우주산업에서 사용되고 있는 비폭발식 분리장치의 종류 및 기술현황에 대해 정리하였으며, 국내연구동향에 대해 살펴보았다.

• 한국항공우주학회지
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• 제30권8호
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• pp.71-77
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• 2002

본 논문에서는 강성 중앙동체에 끝단 질량을 갖는 두 개의 유연구조물이 부착되어 있는 구조 모델의 선회기동과 진동억제를 동시에 제어하는 문제를 고려하였다. 구조모델의 선형 운동방정식을 구하기 위해 유한요소법을 사용하였다. 우주구조물 모델의 LQR문제에 있어서 물리적 의미를 갖는 성능지수를 제공하는 간단한 방법을 제안하였다. 제안된 성능지수는 일반적으로 사용하는 에너지 형식의 성능지수와 비교할 때 수학적으로는 큰 차이가 없으나 물리적으로는 의미있는 차이를 갖는다. 특수해 방법을 사용하여 부등호 제어 제약조건이 있는 시변 LQR문제를 해결하는 수치적 절차를 소개하였다.

• 항공우주시스템공학회지
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• 제10권3호
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• pp.15-22
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• 2016

The on-board appendages of satellites with mechanical moving parts such as the fly-wheel, the control-moment gyro, the cryocooler, and the gimbal-type directional antenna can generate an undesirable micro-vibration disturbance, which is one of the main causes of the image-quality degradation that affects high-resolution observation satellites. Consequently, the isolation of the micro-vibration issue has always been considered as salient, and the micro-vibration is therefore the focus of this study wherein a complex system that can provide the dual functions of a guaranteed vibration-isolation performance and electrical energy harvesting is proposed. The vibration-isolation and energy-harvesting performances of the complex system are predicted through a numerical analysis based on the characteristics that are obtained from component-level tests. In addition, the effectiveness of the complex system that is proposed in this study is verified through an assembly-level functional-performance test.

• 대한조선학회논문집
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• 제43권4호
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• pp.460-466
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• 2006

The three-dimensional RANS equations were applied to analyze the flow field of a submarine. To validate the code, the DARPA SUBOFF bare hull and an eliipsoid at angles of attack of $10^{\circ}\;and\;30^{\circ}$ were simulated and good agreement with experiments was obtained. After the code validation, the flows over the full configuration of DARPA SUBOFF model having a fairwater and four stern appendages were simulated at four angles of attack $(0^{\circ},\;10^{\circ},\;20^{\circ},\;30^{\circ})$ and three yaw angles $(10^{\circ},\;20^{\circ},\;30^{\circ})$ Specifically, the pressure contours and streamlines of fairwater and stern appendage were compared as the angle of attack and yaw angle changed. The variations of hydrodynamic forces were also calculated.

• Mycobiology
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• 제33권3호
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• pp.163-165
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• 2005

In April 2002 and 2003, soft rot on fruit of eggplant (Solanum melongena) caused by Choanephora cucurbitarum was observed in the experimental fields at Gyeongnam Agricultural Research and Extension Services in Korea. The disease began with water-soaking and dark-green lesions, and then the infected tissues were rapidly rotten. Sporangium was subglobose in shape and sized $40{\sim}130\;{\mu}m$. Monosporous sporangiola were elliptic, fusiform or ovoid, brown in color, and measured as $12{\sim}20\;{\times}\;6{\sim}14\;{\mu}m$. Sporangiospores having three or more appendages were elliptic, fusiform or ovoid in shape, dark brown or brown in color, and sized $14{\sim}20\;{\times}7{\sim}16\;{\mu}m$. The fungus grew well on potato dextrose agar between 15 and $40^{\circ}C$ and its optimum growth temperature was $30^{\circ}C$. Based on morphological characteristics, the causal fungus of the fruit soft rot of eggplant was identified as C. cucurbitarum. This is the first report on the soft rot of S. melongena caused by C. cucurbitarum in Korea.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2005년도 ICCAS
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• pp.1641-1644
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• 2005

Magnetic actuation utilizes the mechanic torque that is the result of interaction of the current in a coil with an external magnetic field. A main obstacle is, however, that torques can only be produced perpendicular to the magnetic field. In addition, there is uncertainty in the Earth magnetic field models due to the complicated dynamic nature of the field. Also, the magnetic hardware and the spacecraft can interact, causing both to behave in undesirable ways. This actuation principle has been a topic of research since earliest satellites were launched. Earlier magnetic control has been applied for nutation damping for gravity gradient stabilized satellites, and for velocity decrease for satellites without appendages. The three axes of a micro-satellite can be stabilized by using an electromagnetic actuator which is rigidly mounted on the structure of the satellite. The actuator consists of three mutually-orthogonal air-cored coils on the skin of the satellite. The coils are excited so that the orbital frame magnetic field and body frame magnetic field coincides i.e. to make the Euler angles to zero. This can be done using a Neural Network controller trained by PD controller data and driven by the difference between the orbital and body frame magnetic fields.

• 한국산림과학회지
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• 제94권2호통권159호
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• pp.67-72
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• 2005

The objectives of this study were to identify the period of initiation of floral primordia in black locust (Robinia pseudoacacia L.) and subsequent development of floral buds until following spring. Four mature trees of black locust located in Suwon, Korea were selected. Bud samples were collected from the current-year shoots, starting from mid June to July every week, from August to October and from February to April every month. The buds were fixed in FAA solution, dehydrated, and imbedded in paraffin for microscopic observation. Buds collected on June 16, and 23, 1997, contained primitive primordia that might be interpreted as early floral primordia. By June 30, a bud showed a positive indication of inflorescence primordium with a well-formed shoot apex. All the inflorescence primordia observed throughout the collection periods were always associated with unique hairy appendages around the primordium and enclosed within a sclerenchymatous chamber. By July 7 and 15, a floral apex had early bud scales. By July 22, primitive inflorescence developed into visible arrangement of individual floral primordial By July 29, the inflorescence developed into whirl arrangement of individual floral primordia in a transverse section, but showed little further development until October 15. The inflorescence primordia seemed to over-winter at this stage. Buds collected from February 15 and March 24 the following year also showed no further development of inflorescence primordia. By April 7 the inflorescence started to show further development with elongated axis. At this time individual flowers were easily recognized.

• 한국해양공학회지
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• 제24권4호
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• pp.59-65
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• 2010

This study presents the design procedure for optimizing the semi-planing hull form, including appendages, using numerical and experimental methods. Four different referenced semi-planing hull forms were compared to determine their hydrodynamic performances, and one of the hull forms was modified for optimum operation at high-speed conditions (0.4 < $F_{NL}$ < 0.9). The optimized, semi-planing hull form was tested in the towing tank to investigate its resistance characteristics. Also, the results of the model tests with differing design parameters were used to choose the stern wedge and the spray strip to improve the hydrodynamic performance at high speeds.

• Animal cells and systems
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• 제13권2호
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• pp.161-167
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• 2009

The cuticle of spider's exoskeleton is a hydrophobic and non-adhesive material, but the jumping spiders have the distinctive attachment apparatus for adhesion on smooth dry surface without sticky fluids. We have examined the whole tarsal appendages of the jumping spider, Plexippus setipes with using scanning electron microscope to reveal the fine structural characteristics of the dry adhesion system. All eight legs have the scopulae with a pair of claws on the tip of feet. Each scopula is composed of two groups of setae that are capable of dry adhesion on smooth surface, and the hook structure of the claw is advanced to move on the rough surface. The setae toward the bottom of the tarsal segment are densely covered by numerous setules on the underside which broadened from middle to distal portion. It has been revealed by this research that the contact area of the setule is always a triangular shape, and these cuticular surfaces are connected by the elongated stalks from the underlying setae. It is likely that the nano-scale structures including a triangular depression and a longitudinal groove on each setule could functionate when the spider detach its feet from the substrate.