• KOREAN JOURNAL OF CROP SCIENCE
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• v.37 no.3
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• pp.217-223
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• 1992

Cotton has been an important fiber crop in Korea for a long time. The objective of the study was to investigate the effects of planting and transplanting dates, transplanting density and fertilizer application rate on seed cotton and lint yields, and gross income for barley-cotton double cropping in southern part of Korea. Transplanting culture of upland cotton cultivar Mokpo 4 on June 10 to 20 produced 80 to 83% more in seed cotton yield and 79 to 82% more in lint yield compared with the yields of direct planted on June 10 just after harvesting naked-barley. Mokpo 4 was better than Suwon 17 and Paymaster for the transplanting culture after barley harvest in double cropping. Optimum fertilizer application rate was N 80-P$_2$O$_{5}$ 78-K$_2$O 106 kg /ha, and optimum transplanting density was 70$\times$20cm for the transplanting culture of upland cotton after barley in double cropping system. The highest total yields 5.03 to 5.09t /ha in barley-cotton double croppings were harvested in barley drill-seeding and cotton transplanting culture on June 10 to 20 compared with seed cotton yield 1.51t /ha of the cotton monoculture planted on May 1. Their gross income also was 40% more than that of the cotton monoculture, and 30% more than the cotton direct seeding just after barley harvest on June 10. Cotton intercropping between barley rows provided 2-11% more in gross income compared with cotton direct seeding after barley harvest on June 10. Of the cotton intercroppings between barley rows, cotton intercropping of one row between the barley rows of 60cm width provided 5 to 9% more in gross income than the other cotton intercroppings between barley rows.s.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.27 no.3
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• pp.268-275
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• 1982

This study was conducted to obtain basic informations for breeding and improving cultural practices of sesame (Sesamum indicum L.) through investigation of several agronomic characters of 82 major varieties plants in April 20, May 15 and June 20. Stem diameter and plant height were largest in early planting(April 20). On the contrary, they were smallest in late planting(June 15). Therefore, the later planting, the poorer the vegetative growth on the basis of stem diameter and plant height. Number of capsules per plant and number of grains per capsule were 88 and 54, respectively, in the early planting, while they were decreased to 25 capsules and 40 grains in late planting. The percentage of ripeness and 1000 grain weight 78 and 2.3g in the April 20planting while they were 58% and 2.1g in June 20 planting indicating the later planting, the lower the ripeness. Grain yield per m1 in April 20 and June 20 planting was 112 and 18g respectively. Consequently, grain yield significantly decreased as planting delayed. On the basis of the vegetative and reproductive growth, varieties could be classified into early, conventional, late and indetermediate planting adapted groups. The major yield components were highly and postively correlated with accmulated sunshine hours and temperatures confirming that grain yield was closely related with sunshine and temperature. Among the varieties tested, Gurye and Local 135 had more than 150 capsules. Haenam and Woogang had more than 75 grains per capsule. Since grain yield oflate planted sesame were significantly different among the varieties, breeding of sesame for after barly cropping would be more effective under late cultural condition of after barly.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.40 no.12
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• pp.785-792
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• 2016

In the present study, the effects of non-equilibrium condensation on the drag divergence Mach number with the angle of attack in a transonic 2D moist air flow of NACA0012 are investigated using the TVD finite difference scheme. For the same ${\alpha}$, the maximum upstream Mach number of the shock wave, Mmax, and the size of supersonic bubble decrease with the increase in ${\Phi}_0$. For the same $M_{\infty}$, ${\Phi}_0$, and $T_0$, the length of the non-equilibrium condensation zone ${\Delta}_z$ decreases with increasing ${\Phi}_0$. On the other hand, because of the attenuating effect of non-equilibrium condensation on wave drag, which is related to the interaction between the shock wave and the boundary layer, the drag coefficient $C_D$ decreases with an increase in ${\Phi}_0$ for the same $M_{\infty}$ and ${\alpha}$. For the same ${\alpha}$, $M_D$ increases with increasing ${\Phi}_0$, while $M_D$ decreases with an increase in ${\alpha}$.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.38 no.4
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• pp.336-342
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• 1993

To obtain the basic information necessary for the development of soybean varieties well adaptable to upland-paddy field rotational croppings, the difference of growth characteristics between upland and paddy-field including yield potentials of current recommending soybean varieties were evaluated. The growth characteristics, both above and under-ground, which were measured at flowering stage were generally greater in paddy-field but the number of root nodules was much greater in upland, thus the artificial inoculation was practically recommended for soybean growing in paddy-fields. Mean seed yield was generally higher in paddy-fields than in upland. All soybean varieties showed higher seed yield in the early planting date, April 20, were somewhat susceptible to soybean mosaic virus(SMV), thus they could be escaped from the disasterous endemic necrotic soybean mosaic virus(SMV-N). Soybean varieties showed over 4.0 tons/ha seed yield in the paddy-field were Williams 79, Union, SS77053, and Namhaekong. At the same time, Jangyeobkong and Danyeobkong were the most stable soybean varieties among the tested soybean varieties with less than 10% of coefficient variation values in all planting dates in paddy fields. Compared with Hwangkeumkong which is most widely being cultivated on farmer's fields, soybean varieties showed high yields in paddy-field were higher in plant height, less in the number of branches, and more in the number of nodes on main stem. At the same time, they had medium seed size which would bring the good germination and stands. Disease resistance especially for necrotic soybean mosaic virus was also one of the most decisive factors in seed yields for the early planted soybeans.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.43 no.4 s.346
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• pp.75-80
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• 2006

This paper has proposed a novel dual band transmitter module which can be operating either as an amplifier or as a frequency multiplier according to the input frequency. A conventional dual band transmitter consists of separate amplifiers operating at each frequency band, but the proposed dual band module operates as an amplifier for the IEEE 802.11b/g signal, and as a frequency doubler for the IEEE 802.11a signal according to input frequency and bias voltage. In this paper, we have obtained sharp stop band characteristics by using microstrip DGS(Defected Ground Structure) to suppress the fundamental frequency of the frequency doubler as well as the second harmonic of the amplifier. From measurement result, second harmonic suppression is below -59dBc in the amplifier mode, and fundamental suppression is below -35dBc in the frequency doubler mode. And the designed module has 17.8dBm output P1dB at 2.4GHz and 10.1dBm power for 5.8GHz output, and the output power in the two modes are 0.8dB and 2.8dB larger than the module with ${\lambda}g/4$ reflector, respectively.

• Korean Journal of Medicinal Crop Science
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• v.8 no.1
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• pp.64-68
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• 2000

This study was conducted to determine effects of seeding date, method, and amount on the growth and yield in dill (Anethum graveolens L.). Dill was seeded at six different dates (from Feb. 15 to May 16 at 15 days interval) and two seeding methods (drilling and broadcasting). Required days to emergence, days to flowering and days to maturity were decreased as seeding date was late. In growth characteristics, plant height was significantly different at different seeding times, and lodging affect plant growth in the case of Feb. 15 and Mar. 2 seeding. Essential oil contents was not affected by different seeding times except Feb. 15. Seed yield was different at different seeding times. In seeding method tests, yield was increased by 14% in drill seeding compared with those in broadcast seeding. Regarding the amount of seeding, the yield from the plot of 3 l /10a was increased more 24% than 1 l/10a plot. As a result, this study suggest that dill have to be seeded before April 1 with drill seeding method and the optimum seeding amount appeared to be 3 l/10a.

• 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 Navigation and Port Research
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• v.29 no.10 s.106
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• pp.853-858
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• 2005

Recently, various novel numerical models based on Navier-Stokes equation have been developed for calculating wave motions in the sea with coastal or ocean structures. Among those models, Volume Of Fluid (VOF) method might be the most popular one, and it has been used for numerical simulations of wave motions including complicated phenomena of wave breakings. VOF method, however, needs enormous computation time and large computational storage memories in general, thus it is practically difficult to use this method for calculations in the case of random waves because long and stable computation (e.g for more than 100 significant wave periods) is required to obtain statistically meaningful results. On the other hand if the wave motion is potential motion, Boundary Element Method (BEM), which is a much faster and more accurate method than VOF method, can be effectively used. The aim of this study is to develop a new efficient model applicable to calculations of wave motion and/or wave-structure interactions under random waves. To achieve this, a strictly combined BEM-VOF model has been developed by making the best use of both methods' merits; VOF method is used in a restricted fluid domain around a structure where complicated phenomena of wave breakings may exist, and BEM is used in the other domains far from the disturbance where the wave motion may be assumed to be potential. The verification of the model was performed with numerical results for Stokes' 5th order wave propagation and a random wave propagation.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.23 no.1
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• pp.5-13
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• 1978

An experiment was carried out to find out effective heading date and period of limited ripening in different regions of climatic conditions by sowing date and length of nursery stage of a new variety Milyang 23. Since varieties of Tongil line have a character of premature heading, these do not show the symptom of senescent even though length of nursey stage was delayed. And the delay of heading date is due to late transplanting date, on the other hand, length of nursery stage delayed.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.30 no.2
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• pp.39-50
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• 2018

In this study, the nonlinear interaction of irregular waves with wave breaking and currents around permeable submerged breakwater was investigated with the aid of olaFlow model which is open source CFD software published under the GPL license. The irregular wave performance of olaFlow applied in this study was verified by comparing and evaluating the target frequency spectrum and the generated frequency spectrum for applicability to irregular waves. Based on the applicability of this numerical model to irregular wave fields, in the coexistence fields of irregular waves and currents, the characteristics of wave height, frequency spectrum, breaking waves, averaged velocity and turbulent kinetic energy around porous submerged breakwater with the respect to the beach type and current direction versus wave propagation were carefully investigated. The numerical results revealed that the shape of wave breaking on the crown of the submerged breakwater and the formation of the mean flow velocity around the structure depend greatly on the current directions and the type of the beach. In addition, it was found that the wave height fluctuation due to the current direction with respect to the wave propagation is closely related to the turbulent kinetic energy.