• Journal of Forest and Environmental Science
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• 제30권1호
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• pp.71-75
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• 2014

Forest roads failure is one of the most common problems caused by heavy rainfalls. This study investigated the characteristics on stabilization measures installed for cutting slopes failure of forest road resulted from heavy rainfalls. Three primary factors (slope length, slope gradient, soil type) affecting cutting slope failure were considered and stabilization measures were classified into two types (A type: wooden fence, vegetation sandbag, stone masonry; B type: wire cylinder, gabion, concrete retaining wall) through discriminant analysis based on their capacity of resistance to slope failure. Results showed that A type was mainly installed in such conditions as cut slope <8 m, cut slope gradient $30-40^{\circ}$ and soil type with soil while B type occurred in locational conditions as cut slope length >8 m, cut slope gradient < $30^{\circ}$ and > $30^{\circ}$, and soil type of gravelly soil and rock.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2010년도 추계 학술발표회
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• pp.722-726
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• 2010

Inventory survey is process collecting data about cut slope. It's different from inspection. It contains not only basic information about cut slope, especially location, GPS positioning, height, length, weathering, joint direction, water conditions but also level of danger and damage. Collected data are being used get at status about cut slope along national roads. And It helps judging about priority of detailed investigation. According to results of analysis, we found better method about maintenance of cut slope. Later on, if inventory research is finished, we will understand characteristics of collapse slopes.

• Asian-Australasian Journal of Animal Sciences
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• 제4권1호
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• pp.7-14
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• 1991

An experiment was carried out to investigate the effect of change in length of hay offered on eating and rumination behaviour in sheep using three types of hay diets (L: long, M: 8.0-cm cut, S: 1.2-cm cut) and 3 Japanese Corriedale wethers, and the experiment was designed as $3{\times}3$ latine square. The time spent eating per 100 g hay was significantly shorter with long (L) hay (p < 0.05) than with chopped (M and S) hay, and therefore, the eating rate (g D.M./min.) was significantly higher in the former (p < 0.05) than in the latter. Rumination appearance (the lag time after eating) tended to be longer with long hay than with chopped hay, but not significantly (p > 0.05). Daily time spent ruminating, the actual chewing time and daily number of chews tended to be more in feeding long hay than in feeding chopped hay, but not significantly. Daily number of rumination periods was significantly more with long hay (p < 0.01) than with chopped hay. Cyclic rate tended to be longer with long hay than with chopped hay, in particular, the difference in values between long hay and 8.0-cm cut hay was significant statistically (p < 0.01). The rumination index (time spent ruminating/100 g D.M, eaten) tended to be higher with long hay than with chopped hay, and the difference in values between long hay and 1.2-cm cut hay was significant statistically (p < 0.05). Bolus time was significantly longer with long hay (p < 0.01) than that with 8.0-cm cut hay. The circadian pattern of ruminating time was not changed by the changes in length of hay eaten.

• 원예과학기술지
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• 제30권1호
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• pp.13-20
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• 2012

본 연구는 스탠다드 국화 '백마' 품종의 플러그 묘 생산에 있어서 삽수의 조건이 지상부 생육과 발근 및 정식 후의 절화 생육에 미치는 영향을 알아보고자 실시하였다. 삽수에 잎을 많이 부착할수록 삽목묘의 지상부 생육이 양호하였고, 잎을 4-6장 부착하여 삽목하는 것이 다른 처리에 비해 발근에 효과적이었다. 삽수길이에 따른 삽목묘의 지상부 생육은 큰 차이가 없었으며, 삽수길이를 5-7cm로 처리하는 것이 발근상태가 양호하였다. 삽수 굵기는 3.1mm 처리에 비해 3.6mm와 4.2mm 처리에서 삽목묘의 지상부 생육과 발근이 양호하였다. NAA 처리농도가 높을수록 삽목묘의 지상부 생육이 억제되었으며, 뿌리의 길이도 짧아졌다. NAA $100mg{\cdot}L^{-1}$를 1시간 처리하여 삽목하는 것이 삽목묘의 지상부 생육과 발근에 효과적이었다. 피트모스와 펄라이트를 2:2로 혼합한 배지에서 다른 처리에 비해 뿌리의 길이, 수 및 무게 등이 뿌리의 생육이 양호하였다. 잎이 적은 것보다 4-6개 부착된 삽수의 삽목묘를 정식했을 때, 절화장이 길고, 무게가 무거웠으며, 엽수도 많았다. 삽수길이에 있어서 7-9cm 처리가 절화장, 절화무게, 설상화 수 등 전반적인 절화의 생육에 효과적이었다. 따라서 '백마' 플러그 묘 생산시 7cm 길이에 3.6mm 굵기의 4-6장의 잎을 부착한 삽수를 삽목하는 것이 삽목묘의 지상부 생육과 발근 및 정식 후의 절화 생육을 위해 바람직하였다.

• 한국전자파학회논문지
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• 제11권2호
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• pp.143-150
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• 2000

본 논분에서는 시간영역 유한 차분법을 이용하여 마이크로스트립 안테나의 급전홈에 대한 최적 크기를 제시 하였다. 먼저 여러 모양과 형태의 급전홈을 가지는 마이크로스트립 안테나의 반사손실을 주어진 주파수와 기판에 대하여 수치 해석적으로 계산 하였다. 다음으로 주어진 조건에 대하여 반복 계산 과정을 통하여 최적의 급전홈의 크기름 제시하였다. 그 결과 안테나의 너비가 안테나 길이의 0.78배일 경우에 급전홈의 최적 폭은 50Q 급 전선로 폭의 약 0.42배임을 알았고. 급전홈의 최적 길이는 안테나 패치 길이의 약 0.36배 임을 알 수 있었다. 이 결과는 여러 형태의 급전홈을 갖는 마이크로스트립 안테나를 제작하여 측정함으로써 검증되었다. 또한 급전홈의 최적의 크기는 주파수, 안테나 기판의 높이, 유전율에 대하여 영향 받지 않음을 알 수 있었다.

• 한국터널지하공간학회 논문집
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• 제11권4호
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• pp.419-425
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• 2009

최근에 저토피 및 터널 갱구부에 반개착식 공법을 적용하여 구조적인 안전성과 자연친화성을 높인 사례가 증가하고 있다. 반개착식 공법은 저토피구판에시 원지반을 터널 천단아치에 해당하는 기초까지만 굴착하고 아치형 구조달을 설치하여 복토한 후에 터널하반을 굴착하여 기존 개착공법에서 발생되는 지반 과다절취에 따른 대절토 비탈면 발생과 굴착면 보강에 따른 고비용과 불안정성 증대 문제를 해결할 수 있는 공법이다. 본 논문에서는 저토피 구간에서 반개착식으로 굴착한 Braced Rib Arch의 거동에 대하여 연구하였다. 아치형구조물의 Rib Arch는 지간이 1.8 m인 아치형 강재를 간격재는 목재를 사용하였으며 1:10의 축척으로 4.0 m(폭)$\times$3.3 m(높이)$\times$4.0 m(연장)의 크기를 가진 대형토조에서 실험을 수행하였다. 모형실험결과 아치형 구조물에 작용하는 성토하중은 기존 개착터널에서 사용하는 하부구조물의 폭에 해당하는 상부토체의 크기보다 작은 것으로 나타났다.

• International Journal of CAD/CAM
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• 제6권1호
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• pp.167-172
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• 2006

Recently, wire-EDM became a necessity for many engineering applications, particularly in the dies making. No-Core cut process is helpful for operations in which falling slug can jam the machine or wire. In this paper a proposed CAM system (called NCPP) is introduced, to overcome the limitations of the existing CAM systems in the machining of No-Core cut. The proposed CAM system (NCPP) provides pocketing of No-core cut and optimal selection of the position of starting hole (wire threading point), to minimize toolpath length. It was written for data exchange between CAD-CAM-CNC machines. This data model will become part of the ISO (Data model for Computerized Numerical Controllers) international standard. The NCPP system has been implemented in Visual C++. Many examples are used to illustrate NCPP system. The results show that, NCPP saves the machining time by significant value. This value depends on the shape and complexity of the workpiece that is being cut.

• 소성∙가공
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• 제15권4호
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• pp.311-318
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• 2006

One of the most important quality problems in flat plate leveled from hot rolled coils in cut-to-Iength lines is bowing and cambering when they are cut in small width parts. It is verified analytically and experimentally that residual stress remained in plate is th ε source of the problem. In order to produce low residual stress flat plate from hot rolled coils, the proper conditions of leveling are studied and two things are implemented. One is proper plastic deformation area ratio to reduce residual stress within customer requirement by applying suitable plastic deformation and maintain leveling load within structural strength limit of leveler. The other is maintaining uniform plastic deformation along the width of the plate during leveling. Customer requirement for residual stress is met by applying above 70% of plastic deformation area ratio and uniform deformation along width of coil by adjusting back up rolls according to deformation analysis of work roll and back up roll assembly and leveling tests.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2011년도 제40회 동계학술대회 초록집
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• pp.200-200
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• 2011

Although the cut-off probe, a precise measurement method for the electron density, is widely used in the industry, the physics on the wave spectrum of the cut-off is not understood yet, only cut-off point frequency containing the information of electron density has been analyzed well. This paper analyzes the microwave frequency spectrum of the cut-off probe to see the physics behind using both microwave field simulation (CST Microwave Studio) and simplified circuit simulation. The result shows that the circuit model well reproduces the cut-off wave spectrum especially in the low frequency regime where the wavelength of the driving frequency is larger than the characteristic length and reveals the physics of transmission characteristics with frequency as resonances between vacuum, plasma and sheath. Furthermore, by controlling the time domain in solver of the microwave simulator, the cut-off like transmission peaks above the cut-off frequency which has been believed as cavity effect is verified as chamber geometry effect. The result of this paper can be used as the basis for the improvement of cut-off probe.

• 한국해양공학회:학술대회논문집
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• 한국해양공학회 2000년도 추계학술대회 논문집
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• pp.47-52
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• 2000

F.R.P specimens were made by mixture CM(chopped mat) 450-104 matrix & RC(roving clothes)570-100 Roving, the mixture ratio Resin: hardener (92:8) for tensile test. It was also made of plates by hand lay-up method and was been cured for 24 hours and then was cut tensile specimens in accordance with ASTM D638 Type 3. Knowing exact behavior of bonded area's stress and strain when the tensile test was going on, the test specimens were made of 2 plies laminae of F.R.P in each for supporting cut part in middle of specimen length. And in middle part also were covered of F.R.P plies of 1/2, 2/3 length of specimen in each as well. Also we consider shear stress in adhered area. This study reveals that as plys length is more longer, rupture stress grows remarkably larger.