• KOREAN JOURNAL OF CROP SCIENCE
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• v.30 no.3
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• pp.340-346
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• 1985

Field experiments were carried out to investigate the effects of sowing dates, ferrilizer levels and clipping treatment of forage production and quality of barley and rye in paddy field. The field emergence rates in barley varieties was decreased rapidly at sowing after November. But in rye varieties, it was not decreased even in sowing until Nov. 3. Winter survival of barley and rye varieties were not affected by fertilizer levels. And winter survival decreased with delay in sowing dates in barley varieties, but, it was not influenced by sowing dates in rye varieties. The production of forage dry matter at heading stage was increased with fertilizer levels, and was decreased with delay in sowing dates. Content of crude protein and crude fat of dry forage at heading stage were increased with fertilizer levels. But, content of crude ash, crude fiber and TDN were not influenced by fertilizer levels. As increased fertilizer levels, NFE Content was decreased and TDN yield was increased with fertilizer levels. In comparisons of TDN yield between barley and rye varieties, TDN yield of rye were superior to those of barley. Clipping twice produced more forage yield than clipping once in both crops. However, optimum clipping interval was about 40 days between first and second clipping in rye but not determined in barley. The l2cm clipping height was the highest production in average total yield.

• Journal of The Korean Society of Grassland and Forage Science
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• v.26 no.3
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• pp.171-176
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• 2006

This experiment was carried out to breed the cold-tolerant variety of Italian ryegrass(Lolium multiflorum Lam.) in Grassland and Forages Division, National Livestock Research Institute, RDA, Suwon from 1987 to 2005. New variety, Kowinner as a tetraploid variety was dark green in leaf color and growth habit in autumn and early spring was semi-prostrate and medium, respectively Kowinner as a medium or late-heading variety was 19th May in heading date. Flag leaf length of Kowinner was 29 cm that was the same as control variety, Hwasan 101. Length of longest stem and plant length of Kowinner were 70 cm and 97 cm that was longer 3 cm than those of Hwasan 101, respectively. Stem width of Kowinner was thicker than that of Hwasan 101. Expecially, Kowinner was very good in regrowth. Cold tolerance of Kowinner was slightly weaker than that of Hwasan 101 and slightly stronger than that of Florida 80. Dry matter(DM) yield(12,884 kg/ha) of Kowinner was 8% more than that of Hwasan 101. In vitro dry matter digestibility and total digestible nutrient(TDN) of Kowinner were 76.2 and 63.3% that was 1.6 and 0.4% lower than those of Hwasan 101, respectively.

• Journal of The Korean Society of Grassland and Forage Science
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• v.5 no.2
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• pp.106-110
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• 1985

This trial was carried out to find out the optimum ridge and seeding rate for the seed production of Festuca arundinacea S. (variety Alta). It was composed of three ridge level (12, 18 and 24cm) and four seeding rates (10, 15, 20 and 25kg/ha) in a split-plot design with 4 replications. The experiment lasted from September 1979 to October 1981. 1. The beginning of heading state was May 12 and the date of full flowering stage was June 2. The optimum stage for the seed harvesting of Festuca arundinacea was about 43 days after beginning of heading stage. 2. The number of panicles were 157 per square meter from the best treatment 18cm ridge with 15kg seed/ha. And the 1000 grain weight was 2.79g for the treatment 12cm ridge with 10kg seed/ha. 3. The average seed yield for two years was 681kg/ha and the largest 831kg/ha for the treatment 18cm ridge with 25kg seed/ha. 4. the average germination rate of the harvested seed was 90.7 percent, and it showed a little higher germination rate from the lower level of seeding rate. 5. The average total DM production with two cuttings of aftermath was about 6715kg/ha. According to the increasing seeding rate and narrowing the ridge, DM yield was higher.

• Journal of The Korean Society of Grassland and Forage Science
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• v.30 no.2
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• pp.109-114
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• 2010

This experiment was carried out to know adaptability and forage production and quality of sorghum and sorghum ${\times}$ sudangrass and sudangrass hybrids at paddy field from 2007 to 2008 at Chonnam province. Among growth characters of six Hybrids, 'SX17' hybrid was somewhat strong for waterlogging, and higher sugar content and very good at the 2nd regrowth and disease resistance. Fresh yield of 'SX17' hybrid was the highest as 89,192kg per ha among 6 Sorghum and Sorghum ${\times}$ Sudangrass and Sudangrass hybrids. The dry matter yield of 'SX17' hybrid was also the highest as 21,038 kg per ha. The result of this study showed that 'SX17' hybrid had good growth characters and forage productivity and crude protein (CP) and in vitro dry matter digestibility (IVDMD).

• Journal of The Korean Society of Grassland and Forage Science
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• v.28 no.1
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• pp.1-6
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• 2008

Korditwo is a new orchardgrass(Dactylis glomerata L.) variety developed by the National Institute of Animal Science(NIAS) in 2005. To develope the new variety of orchardgrass, 5 superior clones, Dg8533, Dg9518, EDg9133, U8504 and U8519, were selected and polycrossed for seed production. That synthetic variety was designated newly as "Korditwo", and it's agronomic growth characteristics and forage productivity were examined at Suwon from 2001 to 2002, and regional yield trials were conducted in Suwon, Pyungchang, Youngju, Iksan, and Jeju from 2003 to 2005, respectively. "Korditwo" showed medium type growth habit in fall and spring and short in length of flag leaf and upper internode. Plant height of "Korditwo" was similar to that of standard variety, "Ambassador" and heading date was 4 days later than 14th May compared to Ambassador. Characteristics such as winter hardiness, lodging tolerance, disease resistance of "Korditwo" were stronger or better than those of Ambassador, specially in winter hardiness and lodging tolerance. "Korditwo" showed 10% higher dry matter yield(11.3 ton/ha) compared to Amabassador. Nutritive value was appeared to be similar in both varieties.

• Explosives and Blasting
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• v.27 no.1
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• pp.62-78
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• 2009

Recently, construction techniques have been rapidly developed with reconstruction of old buildings, urban regeneration and efforts of restoring natural ecology, so demolition of deteriorated buildings has been rapidly increasing. Demolition work of building should be executed without damaging surrounding environments according to relevant regulations. There are various demolition methods and among them, explosives demolition is the most practical way for expenses and safety of work. As a part of Daejeon stream ecological restoration project, this thesis is a case of executing demolition of Chung-Ang Department Store which was built 35 years ago as covered structure on the upper part of Daejeon stream with explosives demolition. This structure is 8 stories high, total height of 41.6 m including basement floor, $1,650m^2$ for building area and $18,351m^2$ for total floor area. It is located in the center of Daejeon city where shopping centers and buildings are crowded and main facilities are Daejeon subway (18m), backside shopping center (20m), underground shopping center(15m), Mokchuk bridge, Eunjung bridge(0.25m) and fiber-optic cable(0.25m). In this project, implosion was selected for explosives demolition methods by considering this area being a busy urban area, and this project was executed after examining collapse movement of structure in advance using simulation program not to damage main facilities. Total 80kg of explosives and 1,000 detonators were being used. This project will be a good case of executing explosives demolition successfully by applying implosion on urban area in the country.

• Journal of The Korean Society of Grassland and Forage Science
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• v.30 no.3
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• pp.199-204
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• 2010

A new tall fescue variety (Festuca arundinacea Schreb.) named "Greenmaster" was developed by the National Institute of Animal Science, RDA, at Suwon from 1999 to 2007. For synthetic seed production of this new variety, 5 superior clones, EFa9111, EFa9122, EFa9211, EFa9225, and EFa9234 were selected and polycrossed. The agronomic growth characteristics and forage production capability of the seeds were studied at Suwon from 2003 to 2004, and regional trials were conducted in Suwon, Pyungchang, Jeju, and Ikcsan from 2005 to 2007. Greenmaster showed enhanced winter hardiness, disease resistance, and regrowth ability as compared to Fawn. The dry matter yield of Greenmaster was 11% higher as 19,156 kg/ha than that of Fawn. However, the nutritive value of both varieties was similar.

• Journal of The Korean Society of Grassland and Forage Science
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• v.6 no.1
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• pp.65-70
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• 1986

This experiment was carried out to identify the main pathogens infected with Piper sudangrass and to evaluate the qualitative and quantitative damage of the plants infected with leaf blight (Helminthosporium turcicum PASS) under different levels of nitrogen fertilizer (20, 30 and 40 kg/10a). The experiment was design as a randomized block design with 4 replications at experimental field of Livestock Experiment Station in Suweon, 1984. The results obtained are summarized as follows: 1. The main fungi isolated from sudangrass were identified as Helminthoporium turcicum and Collectotricum graminicolum, but 1 species fungus was not identified. 2. Leaf blight was first found on June 20 and appeared extremely in the regrowth plants from July to September. The rate of attack was associated with increasing of nitrogen fertilization (P<0.01). 3. Fresh and dry matter yields were as much as 47 and 38 percentage lower in leaf blight infected plants (disease severity: V) than those of no visible infection. 4. Concentrations of crude fat and crude protein were decreased in the plants infected with Helminthosporium leaf blight, but lignin content was increased. Dry matter and organic matter digestibility of the plants were negative correlated with the infection of leaf blight(P<0.01).

• Journal of The Korean Society of Grassland and Forage Science
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• v.3 no.2
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• pp.58-66
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• 1983

This experiment was carried out to investigate the effects of the nitrogen rates and cutting heights on the appearance dry weight and death of new bud (branch and tiller) of sorghum-sudangrass hybrid (Sorghum bicolor (L.) Moench). The cultivar used in the present study was Pioneer 988. The experiment was arranged as a split plot design and undertaken in the Experimental Livestock Farm of Agriculture Coll., Seoul Nat'l Univ. in Suweon, 1981 and 1982. The results obtained are summarized as follows: 1. The appearance and death of branch and tiller were not influenced with high nitrogen fertilization. 2. The frequency of the branching was decreased as the low stubble height, and the rate of the tillering was decreased in the high stubble height. 3. The yield of forage mostly depended on the tiller regardless of cutting height, and minor portion of the yield was resulted from the branch. 4. The low cutting height resulted in the increased number of dead bud (p<0.05).

• 한국신재생에너지학회:학술대회논문집
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• 2010.06a
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• pp.58.1-58.1
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• 2010

In solar cell module manufacturing, single solar cells has to be joined electrically to strings. Copper stripes coated with tin-silver-copper alloy are joined on screen printed silver of solar cells which is called busbar. The bus bar collects the electrons generated in solar cell and it is connected to the next cell in the conventional module manufacturing by a metal stringer using conventional hot air or infrared lamp soldering systems. For thin solar cells, both soldering methods have disadvantages, which heats up the whole cell to high temperatures. Because of the different thermal expansion coefficient, mechanical stresses are induced in the solar cell. Recently, the trend of solar cell is toward thinner thickness below 180um and thus the risk of breakage of solar cells is increasing. This has led to the demand for new joining processes with high productivity and reduced error rates. In our project, we have developed a new method to solder solar cells with a laser heating source. The soldering process using diode laser with wavelength of 980nm was examined. The diode laser used has a maximum power of 60W and a scanner system is used to solder dimension of 6" solar cell and the beam travel speed is optimized. For clamping copper stripe to solar cell, zirconia(ZrO)coated iron pin-spring system is used to clamp both joining parts during a scanner system is traveled. The hot plate temperature that solar cell is positioned during lasersoldering process is optimized. Also, conventional solder joints after $180^{\circ}C$ peel tests are compared to the laser soldering methods. Microstructures in welded zone shows that the diffusion zone between solar cell and metal stripes is better formed than inIR soldering method. It is analyzed that the laser solder joints show no damages to the silicon wafer and no cracks beneath the contact. Peel strength between 4N and 5N are measured, with much shorter joining time than IR solder joints and it is shown that the use of laser soldering reduced the degree of bending of solar cell much less than IR soldering.