• Journal of The Korean Society of Grassland and Forage Science
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• v.33 no.2
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• pp.123-130
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• 2013

This study was conducted to investigate the effects of climate change on the growth characteristics and dry matter yields of silage corn hybrids in fields of forage crops of Hanwoo Experiment Station, National Institute of Animal Science, RDA, from Apr. 2009 to Sep. 2011. Corn hybrids were cultivated in Daegwallyeong of Gangwon Province, at an altitude of 760 m. Corn varieties used in this study consisted of 5 domestic varieties and 5 foreign varieties. Differences of silk days according to years occurred at an average of 5.5 days. The silk periods of domestic varieties occurred from Aug. 8 to 12, while that of overseas varieties was from Aug. 5 to 11. Silk days of domestic varieties occurred approximately 3 to 4 days earlier than those of oversea varieties. Silk days of Kwangpyeongok and P3156 belonging to the early varieties were Aug. 8 and 5, respectively. Kwangpyeongok and P3156 were Aug. 8 and 5, respectively. Pyeonganok and DK729 belonged to late varieties. The mean plant height of corn was approximately 231 cm, while those of Kwangpyeongok and Pyeonganok were 236 cm and 237 cm, respectively. The mean stem diameter and ear height of corn were approximately 23.2 mm and 94 cm, respectively. In the case of stem diameters, those of Cheonganok and 33J56 were 86 cm and 80 cm, respectively, while Gangdaok grew to a greater height (enter height) than other varieties. Dry matter yields of Kwangpyeongok and Pyeonganok were higher than those of other varieties. The mean leaf ratio of corn was 39.3%, while that of domestic varieties increased as compared to foreign varieties. The average DM yield of corn was 16,653 kg/ha, while those of 32P75, P3156, Pyeonganok, P3394 and Kwangpyeongok were 18,901, 17,997, 17,675, 17,194, 17,188 kg/ha, respectively. Total digestible nutrient (TDN) yields of 32P75, P3156, P3394, Pyeonganok and Kwangpyeongok were 13,381, 12,590, 12,532, 12,140 and 12,036 kg/ha, respectively. Corn crude protein (CP), in vitro dry matter digestibility (IVDMD), neutral detergent fiber (NDF), acid detergent fiber (ADF) and TDN were 7.8%, 74.2%, 42.4%, 23.5% and 70.3%, respectively. In the case of nutritive values of corn, there was no significant difference between of corn varieties of domestic and foreign origin.

• Proceedings of the Optical Society of Korea Conference
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• 2009.02a
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• pp.225-226
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• 2009

본 연구에서는 마스크리스 노광장치의 두 프로젝션 광학계 사이에 있는 마이크로프리즘 어레이에 관한 연구이다. 마이크로프리즘의 원리와 종류에 대해 알아보고, 마이크로프리즘의 출사부의 모양에 따라 패턴의 모양이 변함을 확인하였다. 그리고 원하는 패턴을 만들 수 있는 마이크로프리즘을 설계하였다.

• Proceedings of the Korean Society of Crop Science Conference
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• 2018.10a
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• pp.63-63
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• 2018

• Korean Journal of Optics and Photonics
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• v.5 no.3
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• pp.356-363
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• 1994

By Gaussian optics, a zoom eyepiece is analyzed, which has the diameter of exit pupil 0.5 em, eyerelief 1 em, and angular magnification $M_a=7~15$. The initial design is based on this analysis. Telescope objective which was previously designed has focal length($(f_u')$ 21.0 em, and its clear aperture is 6.2 em. Zoom telescope has half field angle $\beta=1.5^{\circ}$ at the entrance pupil and at exit pupil it is $\beta'=1.5^{\circ}\times(7~15)=10.5^{\circ}~22.5^{\circ}$. Zoom eyepiece consists of three groups, of which each one satisfies the Seidel 3,d order aplanatization. Final design is obtained by optimization for the finite ray aberration, and the zoom eyepiece is assessed on the basis of the resolution of eyes.f eyes.

• Korean Journal of Optics and Photonics
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• v.31 no.4
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• pp.176-182
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• 2020

The possibility of replacing the condensing-prism film used in conventional backlight units with a light-guide plate engraved with a submicrometer-periodic diffraction grating was investigated. The optimal period for the diffraction grating was determined through simulation and experiment, and the transmission-mode efficiency of the diffraction grating was calculated in terms of the polar angle and azimuthal angle of the incident light. In addition, the effects of the two methods of optimizing the polar angle and the directional angle were compared by simulation, by suggesting the shape and configuration of the light-guide plate, so that more light could be extracted by diffraction. By using a ray-tracing program, the luminance angular distribution of the light-guide plate engraved with the diffraction grating was calculated and compared to the luminance angular distribution for each actual prototype.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.45 no.6
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• pp.392-399
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• 2000

This study was carried out to investigate the physicochemical characteristics of corn silks. Pollination of corn silks was finished within three days after silking, and elongation of open pollinated corn silks was stopped, but unpollinated silks elongated until eight days after silking. Moisture contents of corn silks were about 92-94% at silking stage, but continuously decreased. these were about 70-75% at 30 days after silking. Chlorophyll b was higher than chlorophyll a in corn silks, and chlorophyll a/b ratios of four hybrids were high in this order : silage ＞ sweet ＞ super sweet ＞ waxy corn. Free sugars in corn silks were mainly fructose, glucose and maltose. Their composition rate was 55% of glucose, 42% of fructose and 4% of maltose. Water soluble solid (Brix %) contents of unpollinated corn silks were ranged from 13.7 to 16.8 Brix % and pollinated corn silks were from 12.6 to 13.7 Brix %. Phytic, oxalic, malic. shikimic, glutaric and acetic acid were detected on corn silks. Phytic, oxalic and glutaric acid were considered as a major organic acids in corn silks. Amino acids in corn silks were high in this order : waxy ＞ silage ＞ sweet ＞sweet corn. Serine, glycine and thereoine were contained more than 10%, and five amino acids such as aspartic, glutaric, arginine, alanine and proline were ranged about 5 to 8%. Methionine and cystine, amino acids containing sulfur were contained only small quantity as about 2.1% and 1.3%, respectively. Acetaldehyde, ethanol, acetone, DMS, isobutylaldehyde, cis-3-hexanol, 3-hexe-1-ol, acetate, trans-2-hexanol and pentanol were detected as the volatile components in corn silks, but acetaldehyde and DMS were major volitiles in silage corn silks, and acetaldehyde, ethanol and DMS were major volitiles in waxy corn silks. The length of corn silks was a positively correlated with organic acids (r=${0.556}^*$), and a negatively correlated with amino acids (r=${-0.514}^*$), respectively. Free sugars were positively correlated with all characteristics tested and significantly correlated with organic acid (r=TEX>${0.703}^{**}$), and flavonoids (r=TEX>${0.544}^*$). Chlorophyll was significantly correlated with flavonoid contents (r=TEX>${0.523}^*$). For this reason chlorophyll was evaluated as an indirect selection character for the high flavonoid containing varieties.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.59 no.4
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• pp.445-456
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• 2014

This study was conducted to investigate the kernel characteristics of sweet corn during ripening with different sowing date. Godangok and Guseulok were sown at April 10, July 10, July 20, and July 30 in 2013. Irrespective of sowing date, fresh and dry weight of 100 kernel, starch content, crude fat content, and hardness of sweet corn kernels were significantly increased according to maturation (p<0.05). But moisture content, total sugar content, crude protein content and crude ash content of sweet corn kernels were significantly decreased according to maturation (p<0.05). The changing rates of 100 kernel weight and starch content on kernels were faster at early sowing date than at late sowing date. The moisture content of sweet corn kernels was 68~69% at optimum for harvesting. The degree of sweetness on Godangok was about 1.8 and 1.4 times higher in sowing at July 20 and July 30 than in sowing at April 10. On the other hand, the degree of sweetness was similar regardless of sowing time on Guseulok. These results will be helpful to farmers for fall-harvest sweet corn cultivation and management.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.31 no.1
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• pp.84-90
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• 1986

An experiment was conducted to know the effects of planting dates (March 5, 15, and 25 and April 4) and transparent polyethylene (P.E.) film treatments(tunnel, tunnel slit, and mulch) on air and soil temperatures and growth and yield of a sweet corn variety, Great Bell. Maximum air and soil temperatures and minimum air and soil temperatures were greater at tunnel>tunnel slit>mulch in that order. Differences in maximum air and soil temperatures among the P.E. film treatments were much greater than those in minimum air and soil temperatures. However, when film was opened due to high air temperature over 40$^{\circ}C$ in the tunnel, air temperature was similar but soil temperature was lower com-pared to mulch. High temperature stress could be avoided in tunnel slit without opening film by increase in the number of slits. Cold damage of corn seedlings was avoided by tunnel and reduced by tunnel slit, and frost-damaged seedlings under the mulch were recovered in few days. The number of days from planting to silking was reduced as planting date delayed. At early plantings, tunnel enhanced early growth and silking, but it delayed at late plantings because tunnel was opened during the most of day time due to high temperature. Black streaked dwarf virus(BSDV) disease was more severe at early plantings and it was reduced in tunnel slit at late plantings because plants were grown under the film at the time of infection. The number of marketable ears was similar among all treatments except mulch at March 5 planting where BSDV was severely infected. Gross income was high in tunnel and tunnel slit at March 25 planting which had more larger marketbale ears and tunnel and tunnel slit at March 5 planting which had higher market price.

• Proceedings of the Korean Society of Organic Agriculture Conference
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• 2009.12a
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• pp.296-296
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• 2009

국제기준(Codex)에 부합하는 유기농산물의 생산을 위해서는 저항성 품종의 유기종자 사용을 원칙으로 규정하고 있으나, 현재까지 우리나라의 경우는 찰옥수수 등 주요 식량작물에 대한 유기채종기술이 거의 전무한 실정이다. 본 연구는 찰옥수수 유기채종기술 확립을 위한 기초 자료로 이용하고자 찰옥수수 유기 채종에 따른 파종기별 생육 및 수량특성에 대하여 검토하였다. 유기종자 생산을 위한 채종시험은 홍천군 남면에 위치한 농가 유기포장에서 수행되었으며, 시험품종은 옥수수시험장에서 육성 보급되고 있는 미백2호 및 미흑찰 원종종자를 이용하였다. 파종기는 4월 16일, 5월 4일, 5월 27일 등 3처리로 구분하여 모 부본 동시파종 하였다. 재식밀도는 80${\times}$25cm로 하여 점파하였고 모 부본의 재식비율은 2:1로 웅주간파 하였다. 잡초방제는 흑색 P.E. Film으로 멀칭 재배하였고, 유기질비료는 H사에서 생산된 혼합유박비료를 전량 기비로 시용하였다. 파종기별 출사일수는 미백2호의 경우 4월 파종에서 79일로 가장 길었고, 파종 시기가 늦을수록 출사일수는 짧아지는 경향을 보였다. 미흑찰의 경우에는 미백2호의 결과와 같은 경향으로 파종시기가 늦을수록 출사일수가 빨라지는 경향을 보였으며, 간장 및 착수고 또한 미백2호와 미흑찰 모두 4월 파종에서 가장 높았고, 파종기가 늦을수록 낮아지는 경향이었다. 이삭특성에 있어서 이삭장과 착립장은 미백2호 및 미흑찰 모두 4월 중순 및 5월 상순 파종간에 큰 차이가 없었으나, 5월 하순 파종에서 현저하게 짧아지는 경향을 보였다. 발아율의 경우 미백2호는 4월 중순 및 5월 상순 파종에서, 미흑찰은 5월 상순 파종에서 높게 나타났다. 종실중과 100립중은 미백2호 및 미흑찰 모두 4월 중순과 5월 상순 파종간에 큰 차이가 없었고, 5월 하순 파종에서 현저하게 감소하였다. 10a당 채종수량은 미백2호의 경우 4월 상순 파종에서 217㎏으로 가장 높았고, 미흑찰은 5월 상순 파종에서 164kg/10a으로 가장 많았으며, 두 품종 모두 5월 하순 파종에서 채종수량의 뚜렷한 감소가 나타났다. 따라서 찰옥수수 유기종자의 안정적 채종과 정상수량 확보를 위해서 미백2호는 4월 중순 파종시에 그리고 미흑찰은 5월 상순 파종시에 채종 안전성이 가장 우수한 것으로 판단되었고, 또한 채종수량에 직접적으로 영향을 미치는 1개 이삭당 종실중과 100립중도 크게 증가하는 것으로 나타났다.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.28 no.2
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• pp.227-232
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• 1983

Two single cross maize hybrids planted on May 4 and 25 and June 15, 1982 were grown at 40,000:55,000 70,000 and 85,000 plants per hectare to evaluate plant density effect on growth and grain yield at different planting dates. Two hybrids with different leaf angle (Suweon 19 with horizontal leaves and Suweon 58 with erect leaves) and the same maturity were used. The number of days from planting to silking varied from 74 to 58 days as planting was delayed from May 4 to June 15. However, growing degree days from planting to silking was about $810^{\circ}C$ regardless planting dates. Grain yields of two hybrids were significantly decreased as planting was delayed. The number of ears per 100 plants and the number of kernels per ear of two hybrids were linearly decreased with increasing plant density. The optimum plant density for Suweon 19 estimated by Duncan's method was about 55,000 plants hectare for May 4 and 25 plantings and decreased to 32,000 plants/hectare for June 15 planting. The optimum density for Suweon 58 was estimated to be about 71,000 plants/hectare for May 4 planting and 54,000 plants/hectare for May 25 planting, respectively.