• Korean Journal of Medicinal Crop Science
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• v.4 no.2
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• pp.157-162
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• 1996

Experiments were conducted from 1994 to 1995 to understand the effects of the labor-saving seeding and planting density on growth and root yield of Astragalus membranaceus. The drilling seeder reduced seeding time than the hand seeding; It takes 3. 5hrs/l0a to seed by drilling seeder while 33. 0hrs/l0a by hand seeding, which labor reducing rate was 89. 4 %. Emergence rate in the drilling seeder was increased 17% than in the hand seeding, so the root yield were increased 23% to 136. lkg/l0a in using drilling seeder compared to 110. 3kg in hand seeding. On the effect of planting density on the growth characteristics plant height was long in dense planting and stem diameter was thick in spacious planting. Root diameter and dry root weight root per plant were decreased in dense planting and root yield was highest in optimum planting densities $(6\;row\;(15cm)\;{\times}\;10cm)$ in the harvest of 1 year old plants in Astragalus membranaceus. The gross profit were increased 23% to 1,933 thousand won per l0a in the drilling seeder compared to 1,566 thousand won in the hand seeding, also the managing costs were reduced 18% to 406 thousand won per l0a in the drilling seeder than 494 thousand won per l0a in the hand seeding.

• 한국생물공학회:학술대회논문집
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• 2005.04a
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• pp.65-66
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• 2005

Anaerobic digestion is one of the well-known methods for biological treatment handling of concentrated organic matter such as swine $wastewater.^{1)} The anaerobic digestion can reduce organic loading but also hydrolyze non-biodegradable organic $matter.^{2)}$ The feces from the scrapper-type barn are usually collected to make compost and the urine is discarded with swine-slurry wastewater by ocean-dumping or treated by biological methods. The lagoon, aerobic digestion, anaerobic digestion, SBR, $A^{2}/O$, and UCT have been applied for treating swine $wastewater.^{3)} In this study, as a result of the analysis of swine wastewater, the total and soluble chemical oxygen demand was 130g/L and 60g/L, respectively. And the volatile fatty acid as chemical oxygen demand equivalent was 45g/L, which was 75% of soluble chemical oxygen demand. Before everything else, ammonia nitrogen concentration was 6.5 g/L. From biochemical acidogenic potential test, it was concluded that the enhanced acidification process to manage swine waste should be operated in the ammonia nitrogen concentration of less than 1.2 g/L. In the result of seeding ratio experiments with artificial $wastewater^{4)}, the lag period of acidogens was taken the long time because of the inhibition by the $ammonia^{5)}$, however no difference of period by the seeding ratio was not shown. The Haldane-based biokinetics were also evaluated using a method of fourth order Runge-Kutta $approximation.^{6,7)}$ The nonlinear least squares (NLLS) method with a 95% confidence interval was also used. The ranges of maximum microbial growth rate, ${/mu_{max}}$, and half saturation coefficient, $K_{s}$, for acidogenesis of various seeding ratio with artificial wastewater were 6.1 ~ 12.6 $d^{-1}$ and 45,000 ~ 53,500 mg glucose/L, respectively. Also, the methanogenic microbial yield coefficient, Y, and microbial decay rate coefficient, $k_{d}$, and inhibition substrate concentration, $K_{si}$, for the reactors were determined to be 0.32 ~ 0.465 ${/mu}g$/mg glucose; 0.42 ~ 1.01 $d^{-1}$ and 51,500 ~ 55,600 mg glucose/L, respectively.

• The Korean Journal of Ceramics
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• v.5 no.1
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• pp.50-54
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• 1999

$(Pb_xLa_{1-x}) (Zr_yTi_{1-y})O_3$ (PLZT) thin films with electrooptic effect are promising for the optical application such as display or light shutter. However, it is difficult to use inexpensive and transparent glass substrates because the conventional process for preparation of PLZT requires temperatures above $600^{\circ}C$. In order to deposit a perovskite PLZT thin films at low processing temperatures through alkoxide route, we have offered several seeding processes which reduce the activation energy for crystallization. In this study, we optimized the stacking structure of multilayered PLZT for obtaining single phase perovskite at lower temperatures. As a result, ferroelectric PLZT thin films with different compositions were successfully prepared at a temperature as low at $500^{\circ}C$.

• Korean journal of applied entomology
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• v.33 no.3
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• pp.173-177
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• 1994

his study was conducted to Investigate the occurrence of small brown planthopper (SBPH), LaodeIpahx striatellus Fallen, and the ind~cence 01 rice virus diseases by d~fferent seeding dates in dryseeded rice. The occurrerlce of SBPH was the highest an nce seeded in May 11, followed byMay 1, May 21 and May 31. However. SBPH dld not occur on the rice seeded in June 10 duelo the rice was emerged after peak occurrence of first generailon adult of SBPH. The occurrenceof the first generation adult of SBPH was May 11 and it was 3-day earlier than that of infantnce transplanting. The ~nd~cencofe rice vlrus diseases, rice stripe vilus (RSV) and rice black-streakeddwarf virus (RBSDV), was the most severe at seeding date May 11. and then followed by May1, May 21 and May 31 Thus the incidence of "ce virus diseases was closely related with thedensity of the first generat~on adult of SBPH Rice yield was decreased by later seeding dates, although rice yield from May 1 to May 21 was relatively stable and hqii compared with laterseeding dates. Accordingly, there was slgniilcant relatlonsh~p between rice yield and seeding datesice yield and seeding dates

• Journal of The Korean Society of Grassland and Forage Science
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• v.19 no.2
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• pp.105-114
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• 1999

This experiment was carried out to determine seeding rate and planting date effects on the forage performance and quality of winter rye(Secale cereale L.) at Suweon in 1997 and 1998. The experiment was arranged in a spilt plot design with three replications. Main plots consisted of three seeding rates; 100, 150, and 200kg/ha. Sub-plots consisted of four planting dates; 5 September, 20 September, 5 October and 20 October. The first heading date of rye was not strongly influenced by planting dates. On a day basis, a 1:15 ratio was existed between heading and planting dates of rye, as a 1-day delay in spring heading date for each 15-day delay in fall planting date. Dry matter content of rye for a seeding rate of 200kg/ha was the lowest of 13.6%, and that for the planting dates was decreased to 15.2, 14.2, 14.3, and 13.8% with delayed seeding (P<0.05). There was an interaction between seeding rate and planting date in dry matter content of rye(P<0.01). Acid detergent fiber (ADF) percentage of rye for the seeding rates was not significant and that for the planting dates was decreased to 32.1, 31.6, 31.6, and 29.3%, as the planting was delayed(P<0.05). There was an interaction between seeding rate and planting date for ADF. Effect of seeding rate and planting date on neutral detergent fiber(NDF) of rye was similar to the observations made on ADF. Crude protein content of rye for the seeding rates was not significant, but that for the planting dates was increased to 17.3, 17.7, 18.2, and 18.9%, as the planting was delayed(P<0.05). In vitro dry matter digestibility(IVDMD) of rye for the seeding rates was not significant, but that for the planting dates was increased to 77.5, 80.6, 80.9, and 80.9%, as the planting was delayed(P<0.05). Dry matter yield of rye for a seeding rate of 100 kg/ha was the highest of 9,059 kg/ha, and that for a seeding rate of 200 kg/ha was the lowest of 7,647 kg/ha(P<0.01). In this experiment, the highest forage yield(8,945 kg/ha) was obtained when planting was completed by early October(5 October), with yield decreased as planting was delayed until 20 October (7,249 kg/ha)(P<0.01). This trend was also observed for the crude protein(CP) and in vitro digestible dry matter(IVDDM) yields of rye. A significant interaction between seeding rate and planting date for the dry matter yield was occurred(P<0.01). Based on the results of this experiment, it appears that the forage dry matter yield of rye could be enhanced by sowing from 20 September to 5 October under upland condition in the middle plain area of Korea. The seeding rates from 100 to 150 kg/ha and that of 200 kg/ha would be suitable for the early-fall and late fall sowing, respectively.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.47 no.3
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• pp.167-173
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• 2002

This experiment was conducted to figure out the change of soil physical properties, rice growth and yield with the years of continuous cultivation in direct dry-seeding and no-tillage machine transplanting. Experiments were conducted at NHAES(National Honam Agricultural Experiment Station, RDA, Iksan, Cheon Buk Province, South Korea) with a rice variety "Dongjinbyeo" from 1995 to 2000. In no-tillage machine transplanting cultivation, organic matter in soil was higher than that on direct dry-seeding and was significantly high in topsoil. Problematic weed species were E. crus-galli B., A. keisak H., and L. japonica M. Plant height and tiller number m-2 were higher in common-tillage during the total growth duration. The highest weedy rice occurrence of 27.5% was observed in live years' continuous direct dry-seeding and followed by 6.2%, in four years', and 3.7%, in three years'. The highest yield reduction of 38% was observed in five years' continuous direct dry-seeding. The reduction may resulted from the competition between weedy rice and cultivated rice.

• Journal of the Korean Ceramic Society
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• v.32 no.4
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• pp.482-488
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• 1995

The phase transformation temperature from $\theta$- to $\alpha$-alumina was lowered from 1214$^{\circ}C$ to 114$0^{\circ}C$ in DSC by treating ${\gamma}$-alumina obtained by calcination of boehmite at $700^{\circ}C$ for 2hrswith $\alpha$-Al2O3 seeds (d50=0.36${\mu}{\textrm}{m}$) and 3wt% of the alumina sol. $\alpha$-Al2O3 seeds seemed to lower to the transformation temperature and the alumina sol suppressed the high temperature agglormeration. The effect was increased as the amount of the sol was increased, which was supported by TEM and particle size distribution. For an example, spherical ${\gamma}$-alumina powder with d50=0.54${\mu}{\textrm}{m}$ was prepared by treating the ${\gamma}$-alumina with 9 wt% of the alumina sol and 3wt% of the $\alpha$-Al2O3. It sintered to 99% of the theoretical density at 150$0^{\circ}C$ for 2hrs. and it had relatively homogeneous microstructure with 2~3${\mu}{\textrm}{m}$ sized grains.

• Journal of the Institute of Convergence Signal Processing
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• v.22 no.3
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• pp.104-109
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• 2021

In this paper, we experimentally demonstrate a self-seeding FP-LD (Fabry Perot Laser Diode) to verify the possibility of a new tunable light source that can be used in WDM-PON (Wavelength Division Multiplexing - Passive Optical Network) system. The conventional implementation of WDM-PON using a tunable light source has a disadvantage that the center wavelength of the AWG (Arrayed Waveguide Grating) device and the tunable light source must be precisely aligned. However, the proposed tunable light source has the advantage that the tunable wavelength is automatically aligned with the center wavelength of the AWG as well as simple structure. The implemented tunable light source had a tunable band of about 14 nm or more, and the maximum RIN (Relative Intensity Noise) of about -124 dB/Hz, which showed the possibility of modulating 10 Gb/s signal by an external modulator.

• Journal of The Korean Society of Grassland and Forage Science
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• v.23 no.1
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• pp.49-58
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• 2003

This study was conducted to determine the effect of seeding times and mixture rates of oat and forage rape on the growth characteristics and forage yields during rest periods from March to June after the harvest of potatoes in potato cultivation fields located in the areas about 600m above the sea level in Jeju. The experiment was a split plot desist with seeding times(early, middle and late March) sown . at intervals of ten days from early March to late March as the nam plots and mixture rates as subplots, consisted of oat single(150kg/ha), forage rape single(15kg/ha), oat/rape mixtures 75 : 25% (112.5kg/ha of oat and 3.75kg/ha of rape), oat/rape mixtures 50 : 50％(75kg/ha of oat and 7.5kg/ha of rape) and oat/rape mixtures 25 : 75％(37.5kg/ha of oat and 11.3kg/ha of rape). The germination and establishment of eat and rape were not significantly different among seeding times and mixture rates. The plant heights were higher when seeded middle March compared to seeding times of early and late March. The growth stage of the oats seeded early March was dough stage, while that of oats seeded middle or late March was milk stage. The dry matter yields per ha were higher(p<0.05) when seeded middle March than those of seeding time of early and late March. The crude protein contents of rape single, mixtures and oat single treatments were 15.9, 12.4∼14.5 and 8.5％, respectively.

• Korean Journal of Weed Science
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• v.16 no.4
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• pp.282-291
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• 1996

This experiment was conducted to investigate the phytotoxicity of several herbicides for rice and weed control with herbicides application times and seeding times in flooded direct-seeded rice field. The phytotoxicity of herbieides(bensulfuron methyl+dimepiperate, bensulfuron methyl+mefenacet+dymron, bensulfuron methyl+quinclorac, pyrazosulfuron-ethyl+molinate, pyrazosulfuron-ethyl+thiobencarb, pyrazosulfuron-ethyl+cyhalofop, imazosulfuron+molinate, imazosul-furon+cyhalofop) for rice in different seeding dates was the most high at 7 days after seeding(DAS) Followed by 12 and 17 DAS. In particular, the bensulfuron methyl+mefenacet+dymron showed very high phytotoxicity to rice plants. Weed species occurred in direct-seeding field seeded on May 1 were 10 species (grasses ; 1, broad-leaves ; 6, sedges ; 3) and Echinochloa crus-galli was the most dominant weed among them. Whereas weed species occurred rice field seeded on May 22 were 7 species(grasses ; 1, broad-leaves : 3, ridges ; 3) and Echirochloa crus-galli was the most dominant weed among them. The weed control for annual weeds(Echinochloa crus-galli, Aneilema keisak, and so on) and perennial weeds(Cyperus serotinus, Scipurus juncoides) was remarkably effective at the application of 7 and 12 DAS, but it of Eleocharis kuroguwai was effective at the application of 17 DAS on two seeding times. The yields were decreased significantly at the plot affected severely by herbicides applied at 7 DAS and the plots showed low efficacy at herbicides application of 17 DAS.