• 한국자원식물학회지
• /
• 제15권1호
• /
• pp.43-49
• /
• 2002

옻나무의 묘목생산성을 높이기 위하여 근삽에 있어서 BA의 처리방법과 삽식법을 공시하였다. 삽식 당일에 삽수를 1,000 mg/L BA 용액에 1분간 침지처리가 적하법보다 초기에 신초의 발생율은 낮았으나 5주 이후부터 급격하게 증가하여 10주 후에 는 약 85%로 가장 높았으며, 적하법에서는 BA의 처리 간격이 신초의 발생에 큰 영향이 없었다. 2일 간격으로 100 ${\mu}\ell$의 BA를 적하한 삽수에서 수장이 가장 컸으며 엽수도 많았고, 다음으로 침지처리가 묘소질에 효과적이었다. 분지의 발생은 침지처리구 보다는 적하처리구의 유묘가 삽수와 가까운 지점에서 발생하였다. 평삽이 사삽과 직삽에 비하여 신초의 발생이 약 1주일 빨랐고 신초의 발생도 3주 이후부터 6주까지 급격하게 증가하는 경향이었는데, 삽식 10주 후의 신초발생율은 약 96%로 가장 높았다. 평삽구의 묘가 약 40cm로써 가장 컸으며 평삽구의 묘가 약 40cm로써 가장 컸으며 제 1분지의 발생부위도 낮은 경향이었다. 평삽의 경우 각각 다른 부분에서 발생하는 2~3개의 신초를 각각 분리하여 하나의 묘목으로 생육시킴으로써 묘목의 대량증식에 효과적이었다.

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 2000년도 Handout for 2000 Inter. Machine Tool Technical Seminar
• /
• pp.19-27
• /
• 2000

High speed machining (HSM), specifically end milling and ball end cutting, is attracting interest in the die/mold or aerospace industries for the machining of complex 3D surfaces. HSM of difficult-to-cut materials such as die/mold steels, titanium alloys or nickel based superalloys generates the concentrated thermal/frictional damage at the cutting edge of the tool and rapidly decreases the tool life. Following a brief introduction on HSM and reated aerospace or die/mold work, the paper reviews published data on the effect of cutter/workpiece orientation and cutting environments on tool performance. First, experimental work is detailed on the effect of cutter orientation on tool life, cutting forces, chip formation, specific force and workpiece surface roughness. Cutting was performed using 8 mm diameter PVD coated solid carbide cutters with the workpiece mounted at an angle of 45 degree from the cutter axis. A horizontal downwards cutting orientation proveded the best tool life with cut lengths ∼50% longer than for all other directions (horizontal upwards, vertical downwards, vertical upwards). Second, the cutting environments were investigated for dry, flood coolant, and compressed chilly air coolant cutting. The experiments were performed for various hardened materials and various coated tools. The results show that the cutting environment using compressed cilly air coolant provided better tool life than the flood coolant or the dry.

• 한국지반공학회:학술대회논문집
• /
• 한국지반공학회 2008년도 추계 학술발표회
• /
• pp.930-937
• /
• 2008

From the result of precise field investigation and stability analysis for the cut slope, following results were acquired. 1. The cause of the collapse of cut slope came from circle sliding collapse by fault zone which remained inner weathering zone. 2. The existing destructed soil and rock can be removed by reinforcement. And to prevent the additional destruction, it is judged that applying the method after relaxing the slope would be reasonable. 3. To make cut slope stable, soft rock layer should be done cutting 1:1.5 and 1:2.0 ~ 1:2.5 for weathered rock and soil layer. 4. Heavy water leakage section should be applied horizontal drain method so that water pressure should not act to the cut slope.

• 한국가스학회지
• /
• 제21권4호
• /
• pp.70-75
• /
• 2017

본 연구에서는 차단기능형 수평식 가스밸브와 기존 수직식 가스밸브의 변형거동 안전성을 FEM으로 해석하였다. FEM 해석결과에 의하면, 차단기능형 수평식 가스밸브의 나사부와 가스방출구에 가스내압이 작용할 때 밸브몸체의 우측 끝단부에서 최대 변형량 $4.4{\mu}m$가 발생하였다. 두 번째로 큰 변형량 $2.9{\mu}m$는 안전밸브가 설치된 포트의 끝단부에 형성된 것으로 나타났다. 이렇게 작은 변형량이 발생한 것은 나사부, 가스방출구, 스템 및 스핀들 축이 장착되는 포트, 안전밸브 포트로 구성되는 수평식 가스밸브의 평형이 잘 이루어지도록 설계되었기 때문이다. 반면에 나사부와 가스방출구에 가스내압이 작용할 때, 기존 차단기능형 수직식 가스밸브의 상단부에서 최대 변형량 0.076mm가 형성된 것으로 나타났다. 가스유출구의 좌측 끝단부에서 두 번째로 큰 최대 변형량 0.055mm가 발생하였다. 이러한 변형량은 차단기능형 안전장치의 그루브에 삽입된 오링의 밀봉간극에 영향을 미칠 가능성이 높다. 따라서 본 연구에서는 LPG 용기용 가스밸브의 가스누출을 완벽하게 차단할 수 있는 메커니즘을 갖춘 차단기능형 수평식 가스밸브가 수직식 가스밸브에 비해 우수하다할 수 있다.

• 한국구조물진단유지관리공학회 논문집
• /
• 제4권1호
• /
• pp.147-155
• /
• 2000

Five reinforced concrete rigid frame and masonry infilled wall and cut off type masonry infilled wall were tesed during vertical and cyclic loads simultaneously. Experimental programs were accomplished to improve and evaluate the structural performance of test specimens, such as the hysteretic behavior, the maximum horizontal strength, crack propagation, and ductility etc. Test variables are hoop reinforcement ratio, with or without masonry infilled wall, and masonry method. All the specimens were constructed in one-third scale size. Based on the test results, the following conclusions can be made. For masonry infilled wall(IFB-1), maximum horizontal capacity was increased by 1.45 time in comparision with that of rigid frame(FB-0). For cut off masonry infilled wall (IFBC-1~3), maximum horizontal capacity was increased by 1.73~1.98 time in comparision with that of rigid frame(FB-0). For cut off masonry infilled wall(IFBG-1~3), ductility was increased by 1.48~2.08 time in comparision with that of masonry infilled wall (IFB-1).

• 지질공학
• /
• 제19권4호
• /
• pp.475-482
• /
• 2009

절토사면에 설치된 흙막이벽의 거동은 도심지 굴착공사에 적용된 흙막이벽의 거동과는 다를 것이다. 배면경사지에 설치된 흙막이벽 설계법을 확립하기 위하여는 흙막이벽 및 배면지반의 변형거동을 상세히 규명할 필요가 있다. 따라서, 본 연구에서는 아파트 신축부지 절개사면의 보강을 위하여 앵커지지 흙막이벽과 억지말뚝이 설치된 사면을 대상으로 계측을 수행하였다. 계측결과 굴착초기에는 흙막이벽의 변형이 배면경사지반의 변형보다는 크게 발생되나, 굴착깊이가 깊어짐에 따라 배면경사지반의 변형이 크게 발생되었다. 이는 굴착으로 인한 흙막이벽의 변형이 흙막이말뚝의 강성과 앵커인장력에 의하여 억제되었기 때문으로 판단된다. 앵커에 도입된 선행인장력은 흙막이벽의 거동에만 큰 영향을 미치며, 강우로 인한 흙막이벽의 변형은 지하수위의 변화보다 지표부근에서 침투된 침투수의 영향이 큰 것으로 나타났다. 한편, 굴착배면의 경사진 사면에 설치된 앵커지지 흙막이벽의 수평변위는 굴착배면지반이 수평인 흙막이 굴착의 경우 보다 2~6배 정도 크게 발생하였다.

• 지질공학
• /
• 제15권2호
• /
• pp.155-168
• /
• 2005

절개사면에 설치 된 흙막이벽의 거동은 도심지 굴착공사에 적용된 흙막이벽의 거동과 다르다. 배면경사지 설치된 흙막이벽 설계법을 확립하기 위하여는 흙막이벽 및 배면지반의 변형거동을 상세히 규명할 필요가 있다. 따라서, 본 연구에서는 아파트 신축부지 절개사면의 보강을 위하여 앵커지지 흙막이벽과 억지말뚝이 설치된 사면을 대상으로 현장계측을 수행하였다. 계측결과 굴착초기 흙막이벽의 변형은 배면경사지반의 변형보다 크게 발생되지만, 굴착깊이가 깊어짐에 따라 배면경사지반의 변형이 크게 발생됨을 알 수 있다. 이러한 이유는 굴착초기에 흙막이벽의 변형이 흙막이 말뚝의 강성과 앵커인장력에 의하여 억제되었기 때문으로 판단된다. 앵커에 도입된 선행인장력은 흙막이벽의 거동에만 큰 영향을 미치며, 강우로 인한 흙막이벽의 변형은 지하수위의 변화보다 지표면 부근에서의 침투수에 의해 영향을 받는다 한편, 굴착배면의 경사진 사면에 설치된 앵커지지 흙막이벽의 수평변위는 굴착배면지 반이 수평인 흙막이벽의 수평변위 보다 2-6배정도 크게 발생하였다.

• Geomechanics and Engineering
• /
• 제30권1호
• /
• pp.67-73
• /
• 2022

In this study, the fiber orientation distribution (FOD) is investigated using both micro-CT (computerized tomography) and image analysis of physically cut specimens prepared from Polyvinyl Alcohol (PVA) fiber reinforced cemented Toyoura sand. The micro-CT images of the fiber reinforced cemented sand specimens were visualized in horizontal and vertical sections. Scans were obtained using a frame rate of two frames and an exposure time of 500 milliseconds. The number of images was set to optimize and typically resulted in approximately 3000 images. Then, the angles of the fibers for horizontal sections and in vertical section were calculated using the VGStudio MAX software. The number of fibers intersecting horizontal and vertical sections are counted using these images. A similar approach was used for physically cut specimens. The variation of results of fiber orientation between micro-CT scans and visual count were approximately 4-8%. The micro-CT scans were able to precisely investigate the fiber orientation distribution of fibers in these samples. The results show that 85-90% of the PVA fibers are oriented between ±30° of horizontal, and approximately 95% of fibers have an orientation that lies within ±45° of the horizontal plane. Finally, a comparison of experimental results with the generalized fiber orientation distribution function 𝜌(θ) is presented for isotropic and anisotropic distribution in fiber reinforced cemented Toyoura sand specimens. Experimentally, it can be seen that the average ratio of the number of fibers intersecting the finite area on a vertical plane to number of fibers intersecting the finite area on a horizontal plane (N^V_tot/N^H_tot) cut through a sample varies from 2.08 to 2.12 (an average ratio of 2.10 is obtained in this study). Based up on the analytical predictions, it can be seen that the average N^V_tot/N^H_tot ratio varies from 2.13 to 2.17 for varying n values (an average ratio of 2.15).

• 한국연초학회지
• /
• 제24권1호
• /
• pp.32-37
• /
• 2002

This study was carried out to investigate the effects of suckers on chemical components with vertical and horizontal hanging method during stalk-cut curing in burley tobacco. The elongation and dry weights of suckers were increased until 14 days in vertical hanging method, and until 7days in horizontal hanging method after the beginning of curing. The contents of nicotine, protein-N and $NH_4$-N were decreased at treatment of more suckers during the curing. However, there was no significant difference by the hanging method. Solanone, damascenone, megastigmatrienone and 4-methyl phenol were increased gradually during curing. Those were increased with treatment of fewer suckers compared to treatment of more suckers. There was no significant difference by the hanging method.

• 산업기술연구
• /
• 제26권B호
• /
• pp.73-81
• /
• 2006

A sensitivity analysis about effects of influencing factors on the stability of Soil cut slope was performed. Slope stability analyses were carried out under dry, rainy and seismic conditions. Dominant factors controlling the slope stability were chosen such as cohesion and internal friction angle, unit weight of soil, water table and seismic horizontal coefficient used for the slope stability during earthquake. Parametric stability analysis with those factors was performed for sensitivity analysis. As results of analyzing the sensitivity of factors under dry and rainy conditions, effects of cohesion, internal friction angle and unit weight of soil on the stability of slope are more critical in the dry condition than in the rainy condition. Cohesion and internal friction angle are more dominant factors influencing the slope stability irrespective of dry or rainy conditions than unit weight of soil and the horizontal seismic coefficient. The unit weight and the horizontal seismic coefficient affects crucially the stability according to conditions of slope formation and dry or rainy seasons. For the effect of horizontal seismic coefficient on stability of slope, safety factor of slope is not affected significantly by dry or rainy conditions. However, increase of the horizontal seismic coefficient under the rainy condition floes reduce the safety factor significantly rather than the dry condition. Therefore, it is needed that the location of the water table is assigned appropriately to satisfy the required safety factor of stability in the case of checking slope stability for the rainy and seismic conditions.