• Journal of Biosystems Engineering
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• v.24 no.3
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• pp.217-224
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• 1999

우리나라의 경우 각종 장해와 주년 수요의 증가에 따른 불시재배의 증가로 인하여 저온신장성, 병해저항성 등과 같이 작물의 내성증진을 목적으로 접목묘의 이용이 급속도로 신장되고 있다. 특시 연작장해가 심한 박과형 채소류는 대부분 접목재배가 필요한 실정이다. 그러나 국내의 경우, 접목작업은 거의 수작업으로 행해지며 세밀한 조작과 숙련성 그리고 많은 노력을 필요로 한다. 따라서, 접목 생산성을 높일 수 있는 저가의 자동화 시스템 개발이 요구된다. 다양한 접목법들 중 현재 농가에서 가장 광범위하게 이용되고 있는 호접은 삽접 및 절단접에 비하여 자동화가 어렵고 활착 후 절단작업이 부가적으로 필요하나 접목 후 순화공정이 간단하고 활착률이 높다. 본 논문에서는 호접과 삽접에 대하여 접목 후의 활착률 및 접목에 소요되는 작업시간을 비교하였고, 호접법에 의거하여 작업공정을 생력화한 육묘 자동접목 시작기를 개발하였다. 시작기는 농가조합 및 중규모 육묘장의 설비를 지향하여, 묘판 및 접목묘의 취급을 제외하고 1인 접목작업 형태의 자동화 시스템으로 개발하였다. 시작기는 크게 버퍼기능을 부착한 배치형 육묘장치부, 2세트에 공압 매니퓰레이터, 대목과 접수의 원할한 접목을 위해 설계한 특수 그리퍼, 각고 조절형 절단부, 진동형 클립공급부 그리고 자동 클립 장착장치로 구성하였다. 접목 작업시간은 대략 4ch 정도이나 작업시간의 조정이 가능하도록 하였다. 실험실에서 수행한 간이접목 시험 결과, 절단날이 대목과 접수의 접촉부위를 관통할 때 접촉면이 서로 어긋나는 경우가 발생하였으나 육묘들이 호접에 적정한 기하학적 물성 요건을 갖춘다면 80% 이상의 접목 육묘의 기하학적 물성에 따른 체계적인 접목시험이 필요하다.

• Horticultural Science & Technology
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• v.33 no.5
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• pp.722-729
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• 2015

Powdery mildew (PM) caused by Podosphaera aphanis is a major disease that can result in significant yield losses in strawberry (Fragaria ${\times}$ ananassa Duchesne). For preventing PM, pesticides are usually applied in strawberry. In this study, molecular markers were developed to increase breeding efficiency of PM-resistance cultivars by marker-assisted selection (MAS). An $F_2$ population derived from a cross between PM-resistance 'Seolhyang' and PM-susceptibility 'Akihime' was evaluated for disease resistance to PM and RAPD (random amplification of polymorphic DNA)-BSA (bulked segregant analysis). Among 200 RAPD primers tested, OPE10 primer amplified a 311bp-band present in with 331bp. Sequence alignment performed for searching polymorphisms and six single nucleotide polymorphism (SNP) were found in amplified regions. To develop polymorphic marker for distinguishing between resistant and susceptible, RAPD was converted to cleaved amplified polymorphic sequence (CAPS) marker. Among restriction enzymes associated with six SNPs, Eae I (Y/GGCCR) was successfully digested to 231bp in susceptible. The results suggest that the selected CAPS marker could be used for increasing efficiency of selecting powdery mildew resistant strawberry in breeding system.

• Journal of Biosystems Engineering
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• v.8 no.1
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• pp.9-16
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• 1983

This study was conducted to find out the effects of such parameters as specific draft resistance, slip rate, and fuel consumption rate on plowing performance in paddy fields spread with chopped rice straw. The plowing operation by an 8 P.S. power tiller was carried out in 6 different fields having the soil moisture content of 27~36 percent in dry basis in clay loam soil texture, and applying chopped rice straw of 10, 20, 30 and 60cm in length in the spring of 1982. The effects of soil hardness and moisture content on the plowing performance were also investigated. The results of the study are summarized as follows; 1. The minimum draft during the plowing operation was 110kg in the 30cm rice straw plot having the soil moisture content of 32 percent in dry basis. 2. The multiple regression equation of the specific draft(D) as a function of soil moisture content(M) and cutting length of rice straw(L) was obtained as follows. $D=14.1978-0.8565M+0.0661LxM-2.9685L+0.0133M^2+1.093L^2$ 3. In the 30cm rice straw plot with the soil moisture content of 32 percent in dry basis, the minimum specific draft resistance and the rate of slip were 0.35kg per $cm^2$ and 16 percent respectively. The specific draft resistance varied sensitively in accordance with the soil moisture content, and the slip rate of power tiller was dependent upon the cutting length of rice straw rather than the soil moisture content. 4. The highest plowing performance was 5.3 ares per hour at the soil moisture content of 35 percent and soil hardness of 10kg per $cm^2$. The relationship between the plowing performance and the soil moisture content was obtained by a quadratic equation. 5. The minimum fuel consumption rate in the plowing operation was recorded 6.5 liters per 10 ares in 30cm chopped rice straw plot with the soil moisture content of 32 percent in dry basis.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2010.04a
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• pp.404-407
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• 2010

본 논문에서는 비선형 동적 해석 프로그램인 AUTODYN을 이용해 기둥의 단면 형상의 변화에 따른 폭발 하중의 영향을 분석하였다. 먼저 폭발하중 산정의 타당성을 확인하기 위해 AUTODYN을 이용한 예제해석을 수행하였으며, 폭발하중에 의한 영향을 가장 효율적으로 확인할 수 있는 인자인 압력을 비교하였다. 이를 토대로 기둥 형상에 따른 폭발 저항 성능을 평가하기 위해 같은 단면적과 높이를 갖는 정사각형과 원형 기둥을 모델링 한 후 TNT의 양에 따른 폭발전후의 부피를 비교하였다. 해석결과를 비교해보면 정사각형기둥이 원형기둥보다 폭발에 대한 손상정도는 더 크지만 기둥이 절단되지 않도록 하는 저항성능이 더 우수한 것을 확인할 수 있었다. 비록 철근의 영향을 고려하지 않았지만, 이와 같은 결과를 통해 TNT의 양에 따른 기본적인 폭발거동과 대테러 설계를 위한 기둥 단면 선택시 기초적인 자료로 활용가능 할 것으로 사료된다.

• Journal of Navigation and Port Research
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• v.34 no.10
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• pp.741-746
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• 2010

It is necessary to estimate more accurately the resistance of barge in still water and waves to compute the break load of towline and towing power for safety towing performance. The method proposed by government has calculated the total resistance of barge which is composed of frictional resistance, wave making resistance and air resistance considering the shape of hull and towing speed. However, the added resistance is equally applied with the significant wave height regardless of the type of vessels. In this study, we have carried out the numerical calculation to estimate the added resistance of wigley model in waves and compared with the experiment data to confirm the accuracy of the method. Then the computation was executed for the barge varying shape of the bow. As a result, added resistance of barge was differently occurred i.e. 0.3∼1.1 ton according to encounter angle, 0.4∼1.2 ton according to towing speed and 0.5∼1.1 ton according to shape of bow.

• Journal of Navigation and Port Research
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• v.37 no.1
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• pp.1-7
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• 2013

In this paper the developed prediction technique of wave-making resistance performance for a ship attached with a vertical blade had been verified. Numerical analysis program as a prediction technique had been developed using the Rankine source panel method and the vortex lattice method(VLM). The nonlinearity of the free surface conditions was fully taken into account using the iterative method and the trim and the sinkage of the ship were also considered in the numerical analysis program. Panel cutting method was applied to get hull surface panels. Numerical computations were carried out for a 4000TEU container carrier and the vertical blade was attached 6 different locations astern. To investigate the validity of the numerical analysis program the commercial viscous flow field analysis program FLUENT was used to obtain the viscous flow field around the ship and the model test was performed. The model test results were compared with the numerical analysis results.

• 기계와재료
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• v.2 no.3 s.5
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• pp.120-127
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• 1990

미래지향적 고부가가치의 첨단산업 전반에 걸쳐 기계요소 부품 재료로서 주목받고 있는 화인 세라믹스의 가공에 있어 다이아몬드 연삭 숫돌에 의한 연삭, 절단 가공은 가장 중요한 위치를 차지하고 있는 기계적 제거 가공법이다. 그러나 세라믹스는 고경도, 고강도, 경취성 재료이기 때문에 다이아몬드 지립의 절인 마모가 빨라 능률적인 가공을 장시간 유지하기가 곤란하다. 여기서는 국내 기계 가공 작업 현장에 있어서 부품의 신소재 대체에 따라 필연적으로 사용하게 된 다이아몬드 연삭 숫돌에 대하여 작업자들이 범용 숫돌 사용시의 고정 관념만을 갖고 새로운 공구에 관한 기초 지식이나 Know-how없이 가공작업에 임하는 경우가 많아, 압력 절입 방식에 있어서의 연삭 능률 비교를 중심으로 평면 연삭이나 절단 등의 강제 절입 방식에 있어서의 연삭비, 연삭저항 등의 데이터도 첨부하여 세라믹스 가공을 위한 다이아몬드 연삭공구의 조건에 대해 논하고자 한다.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2015.11a
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• pp.340-340
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• 2015

상지 절단 장애인들을 위한 미관형 의수는 95% 이상의 시장 보급률을 보인다. 하지만 외부 형상 향상에만 연구 초점이 맞추어져 있어 많은 장애인들이 의수를 착용할 때 차가운 표면으로 인해 이질감을 느낀다. 이로 인해 의수 제작 업체 및 절단 장애인들은 착용 시 이질감이 적은 의수의 보급을 희망하고 있다. 그러므로 본 연구에서는 인체와 유사한 온도를 발생시켜 이질감을 감소시키는 의수를 개발하기 위해 유연 기판인 TPU (Temperature Polyurethane)와 PET (Polyethylene terephthalate) 위에 상용 silver nano paste를 3D 프린터로 인쇄하였으며, UV 표면처리를 사용하여 단시간 내에 낮은 저항과, 높은 회로 접착강도를 갖는 회로를 개발 하였다.

• Journal of Aerospace System Engineering
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• v.17 no.2
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• pp.94-102
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• 2023

A nylon wire holding and release mechanism (HRM) has been widely used for deployable applications of CubeSat owing to its simplicity and low cost. In general, structural safety of solar panel with an HRM has been designed by performing structural analysis under a launch environment. However, previous studies have not performed thermal analysis for HRM in an on-orbit environment. In this study, Launch and Early Orbit Phase (LEOP) thermal analysis was performed to evaluate thermal stability of the mechanism in the orbital thermal environment of the pogo pin-based HRM applied to CubeSat. In addition, the effectiveness of the thermal design and performance of the pogo pin-based HRM were verified through a thermal vacuum test.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.50 no.3
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• pp.191-196
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• 2005

Fusarium head blight (FHB) is a severe disease problem that affects the quality and yield of barley grain. The evaluation of FHB resistance is difficult because environmental conditions greatly influence FHB infection and development. The objectives of this study were to: 1) establish an efficient screening method for selecting resistant barley to FHB, 2) compare FHB severity between the cut-spike method and pot-plant method for development of mass screening, and 3) estimate FHB resistance for barley germplasms. Barley cultivars and lines were evaluated for reaction to FHB in controlled-greenhouse condition. Spikes were spray-inoculated with a suspension $(5.0\times10^5\;macroconidia\;mL^{-1})$ of Fusarium graminearum SCK-O4 strain, and then kept in a greenhouse at $18-25^{\circ}C$ with $80-100\%$ relative humidity. Inoculation were employed at 3 different heading growth stages (heading date, three days after heading, and five days after heading). The inoculation was performed in 2 consecutive days in order to avoid escapes. The inoculated plants were maintained in the greenhouse at 4 different free moisture periods (1, 3, 5, and 7 days). The percentage of FHB severity was scored from 0 to 9 according to the rate of infected kernels per spike, and three spikes were evaluated per replication with 3 replicates. There were significant differences of FHB severity depending on the different free moisture periods, but not by the inoculation at different heading stages. The optimum evaluation point of FHB severity in the greenhouse condition was on the 7th day under free moisture condition after inoculation at the heading date. Infection level in cut-spike method highly correlated with that in pot-plant method. This suggested that cut-spike method is useful in evaluating of FHB resistance in barley. Six cultivars, such as Jinkwang, Buheung, Atahualpha 92, Chevron-b, Gobernadora-d, and MNBrite-c, were selected as resistant varieties to FHB. Correlation coefficient for the FHB severity evaluated by the pot-plant method between two seasons was 0.794, indicating the stability and accuracy of the screening method.