• 한국초지조사료학회지
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• 제7권1호
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• pp.18-24
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• 1987

This experiment was carried out to investigate the effects of the final cutting time and cutting height on the winter survival, regrowth, and carbohydrate reserves in stubble, and early spring yield of orchardgrass-dominated pasture before and after the winter season. The experiment was conducted at the experimental field of the Livestock Experiment Station, in Suwon, from October 1985 to early 1986. The results obtained are summarized as follows: 1. Regrowth of plant after the final cut increased significantly (P<0.05) with plot of the early cutting time (Oct. 10) and high cutting height at the final. For winter survival, cut plant should regrow over 15cm in plant height. Therefore limit cutting time and cutting height were forced to be on Oct. 25 and at 6-9cm, respectively. 2. Total water soluble carbohydrate (TSC) content in stubble after the final cut was not significantly changed by different cutting time and cutting height. 3. The percentage of dead plant after wintering was found to be high with plot of the late cutting time and low cutting height at the final cut (P<0.05). And the correlation between the percentage of dead plant after wintering and final plant height before wintering was significantly negathe (r = -0.728**). 4. Fresh and DM yield at the early spring after wintering were increased in the plot of the early cutting time and high cutting height (P<0.05) at the final cut. And significantly positive correlation was observed between the early spring yield and final plant height before wintering (r = 0.720**).

• 반도체디스플레이기술학회지
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• 제8권4호
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• pp.31-36
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• 2009

In this paper, the laser cutting characteristics of the flexible PCB using high power Nd:YAG UV laser were investigated. A specific FPCB model was selected for the experiment. Test sheets were made, which had equal materials and layer structure to those of the outline (OL) region and the contact pad (CP) region in the FPCB. The experiment is made up of two stages. In the first stage of the experiment, the laser cutting fluence was found, which is the threshold fluence to cut the test sheets completely. The laser cutting fluence of the OL sheet is $1781.26{\sim}1970.16\;J/cm^2$ and that of the CP sheet is $2109.34{\sim}2134.34\;J/cm^2$. In the second stage, cutting performance and its qualities were analyzed by the experiment. The laser cutting performance remained almost unchanged for all laser and process parameter sets. The average cutting width (top side/bottom side) of the OL sheet was $40.45\;{\mu}m/11.52\;{\mu}m$ and that of the CP sheet was $22.14\;{\mu}m/10.93\;{\mu}m$. However, the laser cutting qualities were different according to the parameters. The adjacent region of the cutting line on the OL sheet was carbonized as the beam speed was low and the overlap coefficient was high. The surface quality around the cutting line of the CP sheet was about the same. Carbonization and debris occurred on the surface of the cutting line. As a result of the experiment, the cutting qualities were better as the overlap coefficient was made low and beam speed high. Therefore, the overlap coefficient 2 or 3 is proper for the FPCB laser cutting.

• 한국초지조사료학회지
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• 제15권2호
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• pp.124-131
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• 1995

In order to find out optimum seed production date according to different defoliation and flooding period of Italian ryegrass, this studies with Tetrone were canied out on the experimental field of Honam Crop Experiment Station from 1986 to 1988. Treatments included cutting date of Nov. 20 and Apr. 10 and flooding period of 5-25 days. In soil after experiment, organic matter, phosphate and silicate content increased, but potassium content decreased 0.16% than that before experiment. Heading and maturing date of Nov. 20 cutting were same with those of non cutting, those of Apr. 10 cutting lates 6 days to heading date and 2 days to maturing date. Plant height and culm length of Nov. 20 cutting were sirniller to those of non cutting, those of Apr. 10 cutting were shorter and panicle length have no difference between non cutting and cutting. Lodging of cutting treatment was reduced than that of non cutting. Lodgin was increased as flooding period was long, also loding of all treatment occured at 30 days after heading. Two cutting times of Nov. 20 and Apr. 10 have the most fresh yield, while non cutting have the most dry matter yield. Optimun seed productin date was considered to suitable when 35 days after heading (Jun. 14), at this time, seed production was 1,640 to 2,640 kg/ha. Also if flooding j u r y have, seed production was good between 10 days and 15 days after flooding.

• International Journal of Precision Engineering and Manufacturing
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• 제7권1호
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• pp.18-23
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• 2006

Cutting by a high speed laser cutting machine is one of most effective technologies to improve productivity. This paper has presented the cutting characteristics and optimal cutting conditions in a high speed feeding type laser cutting machine by using Tacuchi method in the design of experiment. An L9(34) orthogonal array is adopted to study the effect of adjustment parameters. The adjustment parameters consist of cutting speed, laser power, laser output duty and assistant gas pressure. The surface roughness of sheet metal is regarded as a quality feature. Analysis of variance is performed in order to evaluate the effect of adjustment parameters on the quality feature of laser cutting process.

• 한국초지조사료학회지
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• 제7권2호
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• pp.87-91
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• 1987

This study was carried out to investigate the effects of different cutting times at 0, 10 and 20 days after lodging on the percentage of dead plants and bare ground, live and dead matter build-up, and botanical composition of orchardgrass dominated pasture during the mid summer season. For the test, a randomized block design with 3 replications was treated with 3 different cutting times (July 17, July 27 and Aug. 6). The results obtained are summarized as follows: 1. The percentage of dead plants with cutting times at 0, 10 and 20 days after lodging was 26.3,41.7 and 46.7'%, respectively. 2. The percentage of bare ground with cutting times at 0, 10 and 20 days after lodging was 13.3,26.7 and 3 1.7%, respectively. 3. Dead matter build-up with cutting times at 0, 10 and 20 days after lodging was increased significantly with later cutting (p<0.05). The ratio of live and dead matter build-up with cutting times at 0, 10 and 20 days after lodging was 90.2:9.8, 47.7:52.3 and 39.1:60.9%, respectively. 4. Regrowth yield after lodging was decreased significantly (p<0.05) with later cutting time. 5. The percentage of legumes in botanical composition was increased greatly with later cutting time. The ratio of grasses and legumes with cutting times at 0, 10 and 20 days after lodging was 77.8:21.6,45.5: 50.3 and 36.5:61.7%, respectively.

• 한국공작기계학회논문집
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• 제15권2호
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• pp.59-65
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• 2006

The purposes of using cutting fluid during cutting have been cooling, lubricating, chip washing and anti-corroding. However, the present manufacturing industry restricts the use of cutting fluid because cutting fluid contains poisonous substances which are harmful to the human body. Therefore environmentally conscious machining and technology have more important position in machining process because cutting fluids have significant influence on the environment in milling process. In this study, environmentally conscious machining can be obtained by the way of selecting the optimum machinig conditon using the design of experiment. Cutting using oil-mist showed better cutting characteristics than dry, air and fluid cutting with respect to by cutting force, tool wear and surface roughness. Also, the optimum machining condition for cutting using oil-mist could be selected through Taguchi method.

• 한국초지조사료학회지
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• 제8권3호
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• pp.135-140
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• 1988

본 시험은 林間草地에서 연간 예측회수(3,4,5回)와 예취높이 (3,6,9cm)가 목초의 生育과 收量 및 초지地植生에 미치는 영향을 究明하여 임간초지의 생산량증대와 이용年限延長을 위한 기초자료를 얻고자 실시되었으며, 林間地의 조건은 南向인 소나무 지대로 選光程度는 30%였다. 연간 예취回數별 乾物收量은 4회 예취구(6097kg), 3회 예취구 (5953kg) > 5회 예취구 (5305kg/ha)순이였으나, 館料價植를 고려한 수량차이는 크지 않을 것으로 사료된다. 예취높이별 乾物수량은 예취회수에 관계없이 예취높이가 3,6,9cm로 높아짐에 따라 有意的으로 증가하였으며 (P

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2002년도 추계학술대회 논문집
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• pp.192-197
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• 2002

In this study, examined the cutting characteristics of alumuminum alloy AC8A-T6 that is used to present car piston materials. And in been holding materials machining empirically escape as result that experiment comparison changing the cutting speed and feed on various condition to choose efficient machining condition. The following results can be summarized from this research. 1. As the cutting speed decreased, principal cutting force and thrust cutting force is increased, and reason that cutting force interacts greatly in the low cutting speed is thought by result by BUE's stabilization. 2. The feed speed and cutting speed increase, friction factor is decrescent and the cause appeared the thrust cutting force is fallen than cutting force relatively because chip flow according to increase of the feed rate is constraint. 3. Though specific cutting resistance grows cutting area and the feed rate are few, the cause was expose that shear angle decreases by rake face of tool gets into negative angle remarkably as wear of a cutting tool or defect part of workpiece is cut. 4. Cutting speed do greatly depth of cut is slow, surface roughness examined closely through an experiment that becomes bad, and know that it can get good surface that process cutting speed because do feed rate by 0.1mm/rev low more than 250m/min to get good surface roughness can.

• 한국작물학회지
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• 제42권4호
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• pp.483-488
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• 1997

Brittle culm 특성을 가지는 벼의 가축 조사요 이용성을 위한 적정 예취시기를 구명하여 조사요로서의 수량 및 영양가를 평가하고자 섬진벼 및 Brittle culm인 KL501 품종을 공시하여 무예취, 출수전 및 출수후 10일로 예취시기를 달리하여 1995년 호남농업시험장 수도포장에서 수행된 결과를 요약하면 다음과 같다. 1. 초장은 품종 및 예취시기간 차이가 인정되었으나 재생초장은 품종에 관계없이 1차 예취시기가 빠를수록 컸으며 분얼경수는 품종 및 예취시기간 차이가 뚜렷하였고 재생경율은 1차 예취시기를 빨리 할수록 높아지는 경향이었다. 2. 조단백질, 조지방 및 NFE 함량은 1차 예취시 예취시기가 빠를수록 많았으나 조섬유, 조회분함량은 반대의 경향이며, 2차 예취시에는 1차 예취시기가 빠를수록 조단백질, 조지방 및 NFE 함량이 적어지며 조섬유, 조회분함량은 많았다. 3. 청예수량은 출수기 예취가 다른 예취시기보다 많았는데 섬진벼는 4.49ton/ha, KL501은 4.75ton/ha이며 건물수량은 섬진벼가 1.12ton/ha, KL501은 1.16ton/ha이었다. 4. TDN 함량은 예취시기가 빠를수록 높았으나 2차 예취시에는 1차 예취시기가 늦을수록 높았고 KL501은 어느 예취시기에서나 섬진벼보다 TDN 함량이 높았으며, TDN 수량은 출수기 예취시 섬진벼는 0.60ton/ha, KL501은 0.62ton/ha으로 다른 예취시기보다 많았다.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 1999년도 추계학술대회 논문집 - 한국공작기계학회
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• pp.365-370
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• 1999

SKD11 is one of the most difficult workpiece for machining, so it is necessary to evaluate the machining characteristics of SKD11. The workpiece was made to be the pipe form and heat-treated to HRC45. In this paper, the orthogonal cutting experiment of this material was carried out with TiAlN coated WC cutting tool of 4 kinds of rake angle. After cutting experiment, cutting characteristics of SKD11 were investigated according to variation of cutting speed, feedrate and rake angle.