• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.46 no.1
• /
• pp.35-39
• /
• 2001

It is important to accelerate rooting and establishment of seedlings after transplanting for higher dry matter production and tuber yield in sweet potato cultivation. Therefore, this study was conducted to obtain some information about the effects of vine-cutting holding on rooting and plant growth after transplanting. Vines were cut 20-25cm long and stored for 1, 3, 5, 7 or 9 days in a shade room at 20$\pm$0.5$^{\circ}C$, RH 68$\pm$,/TEX>1%. Peroxidase activity in the vine cuttings increased as the holding period increased and the highest catalase activity was detected in the 5-day holding. Length of main vine, number of branches and nodes on main vine also increased in the 5-day holding. There was little difference in the diameter of main vine among the various holding periods. The data obtained indicate that transplanting of vine cuttings after 5-day holding could promote rooting and vine growth.

• Journal of Welding and Joining
• /
• v.20 no.3
• /
• pp.109-115
• /
• 2002

In this study high power Nd:YAG laser welding of structural steel was investigated. For the test steel blocks of $50{\times}50{\times}200mm$ were cut and machined, and bead-on-plate weld was made on the machined surface. Argon, nitrogen, helium, dry air or mixed gases were used to find the effect of shielding conditions on the bead formation. Results demonstrated that there were Fe I rich region and Fe II rich region in the laser induced plasma column based on the spectral analysis with S-2000 field spectrometer The Fe I region was located at the root of the column near keyhole opening. On the other hand, Fe II region was found at the middle of the plasma column. In the Nd:YAG laser welding, Fe I region emitted continuum which had peak value at wave length of around 710nm, and Fe II region had the peak at 580nm. In the welding of steel by $CO_2$ laser, however, no continuum was observed. There showed two groups of strong spikes in the $CO_2$ laser welding; the first group was displayed at the wave band of 450-560nm. This spike group emitted stronger intensity of light and sharper peaks than those group at 680-800nm.

• Journal of Korean Society of Forest Science
• /
• v.1 no.1
• /
• pp.1-6
• /
• 1962

Hysteresis Loops explaining relationship between E.M.C. and relative humidities of some commercial woods grown in Korea which have not been inspected were studied. Because of Hysteresis Loops are differently constructed among species, the loop of each species is necessary to plot in order to apply for seasoning of wood directly. Therefore relationship between E.M.C. and relative humidities, and Hysteresis Loops were inspected and compaired between species. Small sized ($3{\times}3{\times}1.3cm$) twenty pieces of wood blocks for each species were taken from log which cut few years ago and already attained air dry condition. Five relative humidity conditions (9, 32, 58, 82 and 91%) were controlled to keep constant in the cabinet under temperature $25^{\circ}C$. According to the results, it is concluded that there are considerable differences on the E.M.C. among two types of sorption, eight species and five different relative humidity conditions. Adsorption and desorption curves are showing characteristic Sigmeid Curves and desorption curves always are on the adsorption curves at all compaired species. Average hysteresis ratio is 0.75, the constructed loops of tested species are showing open hysteresis generally and flatten loop constructions of Qnerets aemitissima and Robinia pseudoaeaeia of hard wood species than other soft wood are considered to be established by differences of stability between hard and soft wood.

• Proceedings of the KIEE Conference
• /
• 2006.07c
• /
• pp.1623-1624
• /
• 2006

It is a paper for design, manufacture and estimation of industry inkjet head. Simulations for Actuator, Ink flow and Ejection are executed for securing design ability. Relations between droplet and properties of ink are explained closely through simulation for nozzle. Actually, two silicon plates are made by dry and wet etching and directly bonded. PZT materials is attached on the bended ink flow part and cut to $540{\mu}m$ interval by dicing saw. Actuator was seen variation within 10% between simulation and actual head. Through the ejection estimation, it is shown that stabilized driving voltages change according to viscosity and surface tension of metal ink. Using the metal ink of viscosity of 4.8 cps and surface tension of 0.025 N/m, it is possible to eject the stable droplets with 5m/s, 20 pl, 5 kHz.

• Textile Coloration and Finishing
• /
• v.25 no.3
• /
• pp.194-205
• /
• 2013

In this study, we report dyeing properties and functionality of cotton and silk fabrics dyed with methanol extract from Juniperus chinensis heartwood. Non-aqueous dye of Juniperus chinensis heartwood extracted with methanol was expressed reddish color. It showed relatively good affinity to silk than cotton. Dye uptake of cotton and silk continued to increase according to the increase of the dye concentration. Cotton was not affected by the dyeing temperature and time, however, dye uptake of silk was increased as the dyeing time and temperature were increased. Dye uptake of cotton and silk were the highest at pH 8 and pH 6 respectively. Dyed fabrics showed various colors depending on mordant types and mordant concentration. Washing, light and perspiration fastness were not good. However, rubbing and dry cleaning fastness showed relatively good grade. Dyed fabrics of ultraviolet-cut ability and deodorant ability were improved. Also, dyed fabrics showed very good antimicrobial abilities of 99.9%.

• Textile Coloration and Finishing
• /
• v.25 no.3
• /
• pp.181-193
• /
• 2013

The purpose of this study is to investigate dyeing properties and functionality of cotton and silk fabrics dyed with hot-water extract from Juniperus chinensis heartwood. Water-soluble dye of Juniperus chinensis heartwood extracted with distilled water was expressed YR color series. Dye uptake of cotton continued to increase according to the increase of the dye concentration. Its variation trends were shown to be similar to the isothermal absorption curve of the Freundlich. Dye uptake of silk was better than cotton, increased depending on increasing concentration of the dye, dyeing time and temperature. Its variation trends were shown to be similar to the isothermal absorption curve of the Langmuir. As the pH increased, the dye uptake of fabrics reduced and showed increased on red tinge. Colors of the dyed fabrics were various, depending on dye concentration and the mordant type and mordant concentration. Washing fastness, light fastness and perspiration fastness were not good. However, rubbing and dry cleaning fastness showed relatively good grade. Dyed fabrics of ultraviolet-cut ability and deodorant ability were improved. And dyed fabrics showed antimicrobial abilities of 99.9% against Staphylococcus aureus.

• Journal of the Korean institute of surface engineering
• /
• v.32 no.3
• /
• pp.428-432
• /
• 1999

As metallic surface has its unique lustrous appearance and optical reflectance in visible range of light, the metallization of plastic surface has been an essential drive toward weight reduction for fuel economy and decorations in transportation industry and has been put into practiced from wet chemical-electrochemial to dry vacuum process in view of an environmental effect. Electron-beam metallization was used in this work with an aim at improving the scratchproof surface hardness of plastic substrate with metallic finish character. Thin film of Al ($1000\AA$) and $SiO_2$($7000\AA$) were metallized on substrate of PC and PMMA and the films were evaluated by pencil test for surface hardness and by cross-cut tape test for adhesion. The ion beam treatment improved around twice as hard as non-treat surface. The ion beam is effect on its hardness and adhesion to surface hardened PC substrate.

• Journal of the Korean Society of Industry Convergence
• /
• v.26 no.4_2
• /
• pp.605-613
• /
• 2023

The multi-axis combined machining technology has enabled combined machining, which was difficult. However, the reality is that manufacturing costs are rising due to expensive equipment and there is a shortage of machine operation engineers. The purpose of this research is to present the optimum cutting conditions for the surface roughness when processing the inner diameter of SUS440C, which is an egg material, using a CNC automatic lathe. As a result of measuring the surface roughness, dry machining was the best at R_a0.481㎛ at a spindle speed of 4,000rpm, a feed rate of 0.05rev/min, and a cutting depth of 0.3mm. In wet machining, the highest value was R_a0.317 at a spindle speed of 2,000 rpm, a feed rate of 0.05 rev/min, and a cutting depth of 0.2 mm. The lower the feed rate, the better surface roughness appears. It was found that the feed rate had more influence than the number of revolutions and depth of cut.

• Journal of Korea Water Resources Association
• /
• v.42 no.8
• /
• pp.643-657
• /
• 2009

The major reason to construct large dams is to store surplus water during rainy seasons and utilize it for water supply in dry seasons. Reservoir storage has to meet a pre-defined target to satisfy water demands and cope with a dry season when the availability of water resources are limited temporally as well as spatially. In this study, a Hedging rule that reduces total reservoir outflow as drought starts is applied to alleviate severe water shortages. Five stages for reducing outflow based on the current reservoir storage are proposed as the Hedging rule. The objective function is to minimize the total discrepancies between the target and actual reservoir storage, water supply and demand, and required minimum river discharge and actual river flow. Mixed Integer Linear Programming (MILP) is used to develop a multi-reservoir operation system with the Hedging rule. The developed system is applied for the Han River basin that includes four multi-purpose dams and one water supplying reservoir. One of the fours dams is primarily for power generation. Ten-day-based runoff from subbasins and water demand in 2003 and water supply plan to water users from the reservoirs are used from "Long Term Comprehensive Plan for Water Resources in Korea" and "Practical Handbook of Dam Operation in Korea", respectively. The model was optimized by GAMS/CPLEX which is LP/MIP solver using a branch-and-cut algorithm. As results, 99.99% of municipal demand, 99.91% of agricultural demand and 100.00% of minimum river discharge were satisfied and, at the same time, dam storage compared to the storage efficiency increased 10.04% which is a real operation data in 2003.

• Korean Journal of Agricultural and Forest Meteorology
• /
• v.7 no.4
• /
• pp.282-288
• /
• 2005

This study was carried out to estimate aboveground carbon contents associated with four years of thinning treatment of Quercus acuta stands in Wando Arboretum, Jeonnam. Stand thinning was conducted over four years using stand table projection for each thinning treatment. Ten sample trees were cut in the surveyed area. Estimation of aboveground biomass was made using the equation model $W=aD+bD^2$ where W is oven dry weight and D is DBH in cm. The total aboveground biomass for each intensity treatment area was : control (148.4 ton/ha), light (105.6 ton/ha), moderate (68.7 ton/ha) and heavy (39.1 ton/ha). Aboveground carbon storage for Quercus acuta stands was found by multiplying dry weigh t (ton/ha) by 0.5. Carbon storage and increment after four years was: control (74.2 tonC/ha), light (52.8 tonC/ha), moderate (34.3 tonC/ha) and heavy thinning intensity area (38.2tonC/ha).