• Journal of Korean Society for Atmospheric Environment
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• v.16 no.6
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• pp.585-594
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• 2000

Through an application of Micrometerorological methods, we conducted measurements of Hg fluxes from Nan-Ji-Do which is well known as one of the major local areal sources in Seoul metropolitan area during Match/April of 2000. In the course of our study, we determined the concentration gradients of total gaseous Hg(between 20 and 2000 cm heights) and combined these data with Micrometerorological components to derive is fluxes. It turned out that emission from and dry deposition to soil surfaces occurred at the ratio of 72:27 from a total of 271 hourly measurements. The validity of measured concentration gradients( or resulting fluxes) was evaluated in terms of percent gradient. Accordingly, about more than 95% of gradient data derived were statistically significant. The mean fluxes of Hg across soil-air interface, when computed using the concentrations gradients and relevant parameters, were found at 253(during emission) and -846ng/$m^2$/h(during dry deposition) The occurrences of abnormalously high exchange rates appear to be the combined effects of enormously high gradient values and high transfer coefficients. While the emissions of Hg occurred constantly during the whole study periods, the occurrences of dry deposition events were observed most intensively during very limited time periods(3/29 and 4/3). The results of our study cleary indicated that the studied area is a strong local areal source, while exhibiting great potential as a major sink simultaneously.

• Journal of Welding and Joining
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• v.23 no.6
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• pp.43-48
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• 2005

This work was carried out to obtain sound welds and to select a most suitable binary metal joint among three different dissimilar binary metal combinations such as Zr-4/Ta, Mo/Ta and Ti/Ta(seal tube/sensor sheath) joints fur the instrumented nuclear fuel irradiation test. To do this, Taguchi experimental method was employed to optimize the experimental data. In addition, metallography, micro-focus x-ray radiography and hardness test were conducted to examine the welds. From the weld bead appearance, penetration depth and bead width as well as weld defects standpoint, Zr-4/Ta joint is suggested for the circumferential joining between a seal tube and a sensor sheath. The optimized welding parameters based on Zr-4/Ta joint are suggested as well.

• Laser Solutions
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• v.6 no.3
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• pp.29-35
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• 2003

In semiconductor processing, there are two types of particle contaminated onto the wafer, i.e. dry and wet state particles. In order to evaluate the cleaning performance of laser shock wave cleaning method, the removal of 1 m sized alumina particle at different particle conditions from silicon wafer has been carried out by laser-induced shock waves. It was found that the removal efficiency by laser shock cleaning was strongly dependent on the particle condition, i.e. the removal efficiency of dry alumina particle from silicon wafer was around 97％ while the efficiencies of wet alumina particle in DI water and IPA are 35％ and 55％ respectively. From the analysis of adhesion forces between the particle and the silicon substrate, the adhesion force of the wet particle where capillary force is dominant is much larger than that of the dry particle where Van der Waals force is dominant. As a result, it is seen that the particle in wet condition is much more difficult to remove from silicon wafer than the particle in dry condition by using physical cleaning method such as laser shock cleaning.

• Journal of The Korean Society of Grassland and Forage Science
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• v.10 no.2
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• pp.77-83
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• 1990

A three year's field experiment was carried out on newly reclaimed tidal saline soils to evaluate the salt tolerance and growht characteristics, and their relationship to dry matter production and nutrient quality of main selected pasture species. Nine temperate grasses (14 varieties) and two forage crops (sorghum and pearl millet) were grown under different mulching treatments with medium sand and red-yellow soils (fine loamy materials of Typic Hapludults) from 1986 to 1988. Tall wheatgrass, tall fescue, reed canarygrass and alfalfa showed a good tolerance to soil salinity, especially tall wheatgrass (cv. Alkar) produced 19.6 ton/ha dry matter yield annualy under mulching treatment with medium sand depth in lcm. Pearl millet (cv. Gahi-3) was also evaluated as a salt tolerable forage species. Under salt stress in newly reclaimed tidal lands, plant showed a decrease in the assimirable leaf area (LA) as well as specific leaf area (SP. LA) and a low leaf weight ratio(LWR), and it resulted in a low concentration of crude protein and low digestible dry matter contents. Absorption of macro and micro elements in the plant on tidal lands was increased markedly.

• Journal of Energy Engineering
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• v.13 no.3
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• pp.228-233
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• 2004

This paper reports production of low-molecular weight carboxylic acids from the hydrothermal treatment of representative organic wastes and compounds with or without oxidant (H$_2$O$_2$). Organic acids such as acetic, formic, succinic and lactic acids were obtained. This result increased to 42mg/g dry waste fish entrails in the presence of H$_2$O$_2$. Experiments on glucose representing cellulosic wastes were also carried out, getting acetic acid of about 29mg/g glucose. Studies on temperature dependance of formation of organic acids showed thermal stability of acetic acid, whereas, formic acid decomposed readily under hydrothermal conditions. In general. results demonstrated that the presence of oxidants favored formation of organic acids with acetic acid being the major product.

• Korean Journal of Medicinal Crop Science
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• v.13 no.5
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• pp.298-302
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• 2005

In order to decide the optimum planting time for Bupleurum falcatum L. which is grown widely in Korea, some experiments were carried out in different regions such as mid-north area (Gangwon-do, Gyeonggi-do and Chungcheongnamdo), mid-south area (Jeollanam-do, Jeollabuk-do, Gyeongsangnam-do and Gyeongsangbuk-do). The mid-south area had the highest total saikosaponin contents of 1.001, which is the medicinal ingredients of Bupleurum falcatum L., in accordance with the different Bupleurum falcatum L. regions. Also this area has the highest extract contents of 24.3%. Average dry root yields in mid-north area (Gangwon-do) were $450{\sim}460$ kg/ha at planting time of March 20th to March 30th, 500 kg/ha at the time of March 30th to April 10th, and $470{\sim}480$ kg/ha at the time of March 10th to March 20th in Chungcheongnam-do. The optimum planting time in the mid-south area (Jeollabuk-do) was March 10th to March 30th with the average dry root yield of $490{\sim}550$ kg/ha. Average dry root yield in Euiseong, Gyeongsangbuk-do area was 470 kg/ha, and the optimum planting time was April 10th, which suggested that the yield increased as the planting time was delayed. At Jeju-do, the volcanic soil of farsouthern area, average dry root yield was 510 kg/ha at the time of March 10th, but the yield from non-volcanic soil was lower than from volcanic soil, which had a dry root yield of 470 kg/ha.

• Korean Journal of Organic Agriculture
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• v.9 no.1
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• pp.37-49
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• 2001

This experiment was carried out to investigate the effects of application levels of nightsoil sludge compost(NSC) in 3 and 4 cuttings per annum on the dry matter yields and nutritive value of orchardgrass(Dactylis glomerata L.). Annual nightsoil sludge compost(NSC) were applied at levels of 0, 10, 20, 40 and 80 ton $㏊^{respectively}$ . Relative yields of each cut to annual dry matter yield were 29.9%, 46.% and 23.2% for 1st cut, 2nd cut and 3rd cut in 3 cutting system, 23.7%, 29.3%, 34.0% and 13.0% for 1st cut, 2nd cut, 3rd cut and 4th cut in 4 cutting system, respectively. Significantly higher dry matter yield of orchardgrass obtained were 8.11 ton $㏊^{-1}$ at level of 40 ton ㏊$^{-1}$ $yr^{-1}$ in 3 cutting systems, ranges of 7.50~10.71 ton $㏊^{-1}$ at level of 10~80 ton ㏊$^{-1}$ $yr^{-1}$ in 4 cutting systems than those of non application level of NSC, respectively(p〈0.05). The mean efficiency of dry matter production to application of NSC(kg DM/ton NSC) were 46 and 102 kg in 3 and 4 cutting systems, respectively. Although th contents of crude protein(CP, %) of orchardgrass were significantly higher at the application levels of 10~80 ton $㏊^{-1}$ $yr^{-1}$ -1/ by NSC than those of the application levels at the 0 ton $㏊^{-1}$ $yr^{-1}$ in 3 and 4 cutting systems(p〈0.05), the contents of neutral detergent fiber(NDF, %) and acid detergent fiber(ADF, %) were lower in NSC plots than those at the non-application plots of NSC. The contents of total digestible nutrient(TDN, %) and relative feed value(RFV) of orchardgrass were significantly increased with increase the applicaton levels of NSC(p〈0.05).

• Journal of The Korean Society of Grassland and Forage Science
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• v.11 no.3
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• pp.189-194
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• 1991

This experiment was carried out to investigate the effect of pure mineral nitrogen fertilization on dry matter yield and to determine the amounts of advisable mineral nitrogen according to difference of annual precipitations in permanent grassland. The results obtained were as follows: 1. Only PK-fertilizing without additional mineral nitrogen application produced 6. 9 tonlha of annual dry matter yields on average in relatively wet years that was higher than in rel. dry and normal years under 3-cut system by 0. 7 and 0.6 ton DMIha, respectively. 2. Due to the lesser rainfall the nitrogen-efficiency was substantially higher with heavy dressing of nitrogen fertilizer. The absolute differences in yield between rel. dry and wet years were 0.4 and 0.7 ton DMIhalyear respectively when dressed with 90 and 120 kgN/ha/cut at 4-, 5- and 6-cut systems, whereas at 3-cut system differences around 1.3 and 1.1 ton Dhllhalyear respectively were recorded. 3. In rel. dry years the most efficient N-dressing rates per ha and year tended to be slightly higher than in rel. wet and normal years. Particularly at 5-cut system 4-7 kg/ha/cut of more nitrogen fertilization was required in order to obtain the highest overyields. 4. The N-dressing rates needed to maintain a nitrogen-efficiency of 8 to 16 kg DM/kg N tended to be stronger particularly at high cut system, and also in rel. dry years higher dressing rates were required that in rel. wet and normal years.

• Journal of Animal Environmental Science
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• v.8 no.2
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• pp.107-110
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• 2002

This study was carried out to investigate the quantity of Holstein dry cow manure excreted and their characteristics. The results obtained in this study were summarized as follow; The average body weight of the Holstein dry cow during experiment was 619.9kg. The feed intake(DM basis) and water consumption was 10.7, 38.6kg/day/head, repectively. The manure production of Holstein dry cow was 44.8kg/day/head (feces 26.9, urine 17.9kg). The moisture content of feces and urine was 84.5%, 95.3%, respectively. Wastewater pollutant concentration of $BOD_5$(Biochemical Oxygen demand), $COD_{Mn}$ (Chemical Oxygen demand), SS(Suspended Solids), T-N(Total Nitrogen) and T-P(Total Phosphorus), excreted from Holstein dry cow was 16,874,55,763, 87,333, 2,353, $368mg/{\ell}$ in feces and 5,621, 8,673, 518, 2,423, $3mg/{\ell}$ in urine, repectively. The fertilizer content of manure, N(Nitrogen), $P_2O_5$(Phosphoric acid) and $K_2O$(Potassium oxide) was 0.24, 0.08, 0.15% in feces and 0.24, 0.001, 0.30% in urine, respectively.

• Journal of Plant Biology
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• v.17 no.3
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• pp.118-126
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• 1974

Mulberry plants cultivated in mid-Korea were studied on the growth habitat, canopy type, productive structure and vertical light intensity in relation to the quality of mulberry leaves for sericulture. The growth in length of new branch of summer cut mulberry in spring was vigorous on the uppermost of old shoot. Numbers of leaves on a branch were barely 4 leaves on lower than 20th branch from base, but those were 13 leaves on higher than 24th branch. Area of leaves completely expanded was broad on high branch, but narrow on low one. The form of canopy, the type of productive structure and the vertical light distribution depend upon varieties of cultivated mulberry plants were classified according to characteristic of each variety in two groups, respectively; globular and columnar form in canopy, broad leaves and narrow leaves types in productive structure, and seriously obstructured the light and fairly transmitted the light into lower leaf stratum invertical light distribution. Out of varieties of mulberry investigated, Suwon No. 4 and Rosang were belong to the former characters, but Illchiroe and Kaeryangsubun were to the latters. The values of leaf dry matter index and dry matter production produced by leaves were increased in direct proportion to the height of leaf stratum; the leaf dry matter index of the uppermost leaf was twice as much that of the lowest, and the dry matter production by the highest leaf was 17 times compared with that by the lowest leaf. It is assumed that the meagre leaves occurred in the lower leaf stratum of Suwon No. 4 and Rosang were caused to diminished the dry matter index and dry matter production in the under leaves of plant, which were affected by receiving the weak light.