This study aims at developing the paraglider with the enhanced function and safety of flight by performing the simulation and test of flight with two slots at each wing tip of canopy. When the distributions of velocity and shear stress at wall around the canopy were compared, the canopy with slots showed the distribution of less velocity and shear stress at wall significantly than the canopy without slots by confirming the safety of the paraglider. Series of simulation were conducted to achieve the optimal shape of slots by applying various sizes and positions of the slots, resulting nine cases with the better outcome on which flight tests were based. The flight test results in this study confirmed that canopy with slots showed the improved flight function by increasing the maximum velocity, decreasing the minimum velocity, delaying the stall timing significantly and consequently improving the safety of the paraglider. Based on the simulation and flight tests, three cases with the best outcome have been selected for merchandising strategies.

This study was to develop the automatic fin tube cutting machine, equipped with semi-automatic supplying board, automatic transfer equipment, fin tube holder, and cutting equipment assembly for the effective and safe fin tube cutting. The development of the automatic fin tube cutting machine resulted in improving 150% of productivity, 300% of cutting length precision, and 230% of a vertical angle precision on the cutting plane. In addition, we were able to secure safety of the workers and to automate production management, and further to reduce environmental pollution by recycling cutting chips.

When a bellows is subjected to various deformation conditions such as angular rotation, axial displacement or lateral deflection, the stress is produced at each convolution. These deformations play a significant role in the analysis of strength. Because of geometric complex, it is difficult to analyze the mechanical behavior of bellows. The symmetrical deformation problems of the bellows have been discussed in the study. These problems were investigated by the finite element method. The bellows was meshed with 8 node shell elements and elastic analysis was performed. The mesh consists of 112,800 elements and the lateral deflection from 0 to 21mm, the axial displacement from 0 to 6mm and the angle of rotation from 0 to 0.21 degree was applied at the end cap for the boundary condition. The effects of boundary conditions such as the angle of rotation and the lateral deflection on the stress concentration for the bellows was studied. In addition, the relationship between minimum von-Mises stress and angle of rotation and deflection of bellows was obtained

This paper presents a method for the assesment of vibration fatigues in engine exhaust system. Analysis technologies by virtual model can reduce the number of physical tests and development cycles. The prediction processes are based on the construction of FE model for the exhaust system, normal mode analysis, and frequency response analysis. The analysis results(1st mode: 152Hz) of eigen frequencies are compared with the modal test results(1st mode: 151Hz). And frequency response analysis for accelerations and stresses at critical locations were also presented. The analysis method could be applied to assess the vibration fatigue for the engine exhaust manifold. As a result, maximum stress occurred at the end of diffuser and its frequency shows around 1st natural frequency of exhaust system. It shows a good agreement between numerical and experimental results.

Recently, most of moving parts at automobile engine are required to be lighter and compacter and have high performances such as strength and endurance, etc. In particular, the crankshaft is subject to complex loadings such as shear, bending, and torsional loads as well as inertia and torsional vibration. To investigate critical area and optimize the shape of crankshaft at intial design stage, it is necessary to consider the dynamic effect of crankshaft. This paper carried out structural analysis of engine crankshaft by using multi-body dynamics and multi-axial fatigue analysis

국내 4개 지역으로부터 채집된 배추좀나방(Plutella xylostella)의 미토콘드리아 DNA중 COI 유전자 일부 (438 bp)의 염기서열을 결정, 유전적 다양도 및 유전자 이동정도를 파악함으로써 집단 유전적 구조 및 특성에 대하여 연구하였다. 총 21개체로부터 13개의 mtDNA haplotype을 얻었으며 이들의 변이는 0.3~1.4%로 다른 곤충을 대상으로 한 유사연구와 비슷한 크기를 나타내었으며 haplotype 다양도는 매우 높았다(평균 h=0.81). 지리적으로 먼 제주도의 개체군과 경남 김해 두 지역(11km 거리)의 개체군을 비교한 결과, 통계적으로 유의한 정도의 유전적 격리(p<0.05%)는 전혀 관찰되지 않았으며, 대신 상당한 정도의 세대당 암컷 이동률(Nm=2-30)을 보였다. 또한 GenBank에 등록된 하와이의 배추좀나방 haplotype은 본 연구에서 얻은 것들과 유전적으로 흡사하였다. 종합적으로, 국내 배추좀나방은 전체적으로는 많은 haplotype수에 기인한 적절한 크기의 유전적 분화율을 보유하고 있으며 국지적으로는 상당한 이동력에 의한 장거리 이동으로 개체군내 높은 haplotype 다양도를 보이며 동시에 지역간의 유전적 유사성을 나타낸다고 요약되었다.

짚시나방(Lymantria dispar)의 배자 발생에 미치는 유약호르몬의 영향을 조사하기 위하여 유약호르몬 유사체인 methoprene을 알에 도포처리(topical treatments)하여 부화율, 부화 유충의 생체량 및 알의 단백질과 탄수화물 함량 변화를 조사하였다. Methoprene 농도별 처리는 부화율에 영향을 미쳐 methoprene 처리군이 대조군(78.5%)에 비해 낮은 부화율을 나타 냈으며 5.0 처리군에서 가장 낮은율(42.5%)을 보여 주었다. 부화 직후 1령 유충의 생체량은 대조군이 0.7525mg으로 가장 높았으며 methoprene 농도 처리 순으로 감소하다가 5.0 처리군에서 0.6487mg으로 최하치를 나타냈다. 처리군별로는 대조군과 0.5 처리군이, 1.0와 2.0 처리군의 생체량이 유사하였다. 배자 발생중 알의 단백질 함량 변화에서 0.5 처리군은 2, 4일째 대조군과 뚜렷한 차이를 나타냈으며, 탄수화물도 대조군에 비해 처리군이 낮은 함량을 유지하였다.

초 록 재래종 밤나무와 저항성 품종 밤나무(축파, 단택)에 기생하는 밤나무 혹벌의 유충에서 유약 호르몬과 유약호르몬 특이에스테라제의 활성도를 Gas liquid chromatohraphy (R ller et al.1965), Galleria cuticle wax 검사 (de Loof & van Loon 1981) 및 Liquid scintilation counter (Hammock & Sparks 1977)로 비교 측정한 결과는 다음과 같다. 유충에서 GLC로 분리한 유약호르몬은 양군 모두에서 유약호르몬 I(JH-I)로 동정되었다. 저항성 품종(축파, 단택)에 기생하는 밤나무 혹벌의 유약호르몬 함량은 35,800 GU/g와 30,900 GU/g이고, 재래종에 기생하는 밤나무 혹벌의 유약호르몬의 함량은 28,600 GU/g으로 나타났다. 유약호르몬 특이 에스테라제 활성도는 저항성 품종(축파, 단택)에 기생하는 밤나무 혹벌은 1.48 n mole/min/ml와 1.63 n mole/min/ml, 그리고 재래종에 기생하는 밤나무 혹벌은 1.89 n mole/min/ml로 측정되었다. 유약호르몬 함량은 재래종 밤나무에 기생하는 밤나무 혹벌보다 저항성 밤나무(축파, 단택)에 기생하는 밤나무 혹벌에서 더 높았으나, 유약호르몬 특이에스테라제 활성도는 저항성 밤나무(축파, 단택)보다 재래종 밤나무에 기생하는 혹벌에서 더 높게 나타나 서로 역비례 경향을 나타냈다.