• Research in Plant Disease
• /
• v.7 no.1
• /
• pp.42-48
• /
• 2001

The effect of cultural, physical and chemical control methods on the population density of Meloidogyne arenaria second-stage juveniles (J2) and on fruit yields of oriental melon was investigated at Seongju Fruit Vegetable Experiments Station, Kyungpook province, Korea, for two years from 1999 to 2000. Crops used in a rotation prior to Oriental melon were rice, corn, sesame, and green onion. The physical methods used were either solarization, soil addition or soil drying, and a nematicide, fosthiazate of granular formula, was used as the chemical method, applying at a rate of 300g a. i./10 a. Growing rice in the rotation, solarization, and soil addition controlled the nematode disease most effectively, reducing the number of J2 by 90% and increasing fruit yields two times. However, the effects of these control methods on the J2 population were limited to the early growing season; the J2 population increased later, suggesting that additional control practices may be needed in the following season. The next effective control methods were use of corn in the rotation, the nematicide application, and soil drying. The nematicide application was effective only for the early fruit yield, but neither for the late nor for the total yields. Use of sesame or green onion in the rotation was not effective in controlling the nematode.

• Journal of Ecology and Environment
• /
• v.38 no.2
• /
• pp.175-183
• /
• 2015

Extremely strong winds and heavy rainfall caused canopy gaps in a mixed Abies holophylla broadleaf forest and a Quercus mongolica-dominated forest in Odaesan National Park, Korea in October 2006. The impact of the combination of strong winds and torrential rain on the development of forest gaps and canopy structures were investigated. The mean size of newly created gaps were $205m^2$ in the mixed forest and $86m^2$ in the Quercus forest, and were created by 2.8 and 1.4 gapmaker trees, respectively. Among the 73 trees lost in the mixed forest, 59% succumbed because of direct wind damage while 41% were struck by neighboring trees that fell into them. Most of these trees downed by wind were uprooted (74%), while the trees downed by neighboring tree falls snapped (78%). 21 trees in the Quercus forest died from direct wind damage, and 57% of them were uprooted. Although the relative density of Abies nephrolepis and A. holophylla represented only 0.2% and 6.4%, respectively, of all species in the intact mixed forest, they accounted for 27% and 15%, respectively, of all trees affected by wind on that site. In fact, 85% of the total A. nephrolepis and 91% of the total A. holophylla in the mixed forest fell directly due to strong wind. By contrast, only one Abies species, A. nephrolepis, was found in the Quercusdominated forest, and it accounted for 7.3% of the species composition. These findings suggest that A. nephrolepis and A. holophylla are particularly susceptible to high winds because of their great heights and shallow root systems.

• Korean Journal of Medicinal Crop Science
• /
• v.9 no.1
• /
• pp.76-82
• /
• 2001

This study was conducted to find out the optimum ranges of soil physical properties for wasabi growth by the relationship of soil physical properties and plant growth. Soil bulk density and hardness were higher in decomposition of granite and river sand than hydroball. This root distribution of surface layer was higher in decomposition of granite and river sand than hydroball. Growth characteristics and yield were higher in hydroball than decomposition of granite and river sand. In inlet site, the marketable rhizome weight in decompasition of granite, river sand, hydroball were 298kg/10a, 401kg/10a, 766kg/10a, respectively. But outlet, the weight in three soils were 251kg/10a, 256kg/10a, 633kg/10a, respectively.

• Korean Journal of Medicinal Crop Science
• /
• v.18 no.2
• /
• pp.74-78
• /
• 2010

This experiment was carried out to select suitable organic matter in To-jik nursery (self soil nursery) for complement To-jik nursery's defects that are deterioration of raw material by poor quality of seed ginseng and reduction of the quantity in seed ginseng production. Organic matter used were Yacto, rice bean, defatted rice bran, soybean cake and their mixture. As follows, bulk density in soil physical property by treating organic composts was the greatest in soybean cake and the next was followed by mix, Yacto, defatted rice bran, and rice bran treatment in order. Soil pore space ratio was totally the opposite; that was rice bran the first and followed by defatted rice bran, Yacto, mix and soybean cake treatment. The incidence rate of damping off by treating organic composts was 1.5% in both soybean cake and mix while the others was 1.0%. Emergence time was the same among treatment on April 16 and Emergence rate was the highest at 73% in Yacto. There was no significant differences among treatment in the growth of aboveground part but it was a little better in defatted rice bran treatment. In Yacto treatment, the growth of underground part, total root number per kan, rate of first grade ginseng seedling, and rate of usable ginseng seedling etc. were entirely higher but there was little differences. Using defatted rice bran was slightly lower in productivity compared to Yacto, but the possibility was high as a alternative for Yacto in a view of managing cost down.

• Restorative Dentistry and Endodontics
• /
• v.20 no.1
• /
• pp.275-288
• /
• 1995

The inhibitory effect of cell wall extracts of streptococci, have been investigated to know host-parasite relationship or pathogenesis of abscess formation. Streptococci isolated from the infected root canals were sonicated to get cell wall extracts which have been known as one of the factors of pyogenesis. Lymphocytes separated by density gradient were stimulated with phytohemagglutinin and exposed to cell wall extracts of Streptococcus sanguis, S. mitis, S. uberis, S. mutans (ATCC 10449), and S. faecalis (ATCC 19433). [$^3H$]-thymidine uptake of lymphocytes was analyzed with scintillation counter and lactate dehyrogenase (LD) activity was measured with autochemistry analyzer. S. faeealis had the strongest inhibitory effect. beginning at $100\;{\mu}g/ml$ concentration of sonic extracts. S. sanguis and S. mitis had inhibitory effect at $300\;{\mu}g/ml$, while S. uberis and S. mutans showed no inhibitory, effect on DNA syntheis even at $300\;{\mu}g/ml$. Each streptococci showed different inhibitory effect on the DNA synthesis of lymphocytes, which finding indicated wide spectrum of susceptibility of lymphocytes according to streptococcus spp. There were no significant difference of LD activities between control and each streptococcal extracts. Streptococcal sonic extracts did not affect the morphological findings or number of colonies activated lymphocytes. These finding suggested the inhibitory effect of sonic extract of streptococci to lymphocytes could be detected by DNA synthesis inhibition, not by cellular membrane damage.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.13 no.9
• /
• pp.729-734
• /
• 2000

Recently, Very Large Scale Integrated (VLSI) circuit & deep-submicron bulk Complementary Metal Oxide Semiconductor(CMOS) devices require gate electrode materials such as metal-silicide, Titanium-silicide for gate oxides. Many previous authors have researched the improvement sub-micron gate oxide quality. However, few have reported on the electrical quality and reliability on the ultra thin gate oxide. In this paper, at first, I recommand a novel shallow trench isolation structure to suppress the corner metal-oxide semiconductor field-effect transistor(MOSFET) inherent to shallow trench isolation for sub 0.1${\mu}{\textrm}{m}$ gate oxide. Different from using normal LOCOS technology deep-submicron CMOS devices using novel Shallow Trench Isolation(STI) technology have a unique"inverse narrow-channel effects"-when the channel width of the devices is scaled down, their threshold voltage is shrunk instead of increased as for the contribution of the channel edge current to the total channel current as the channel width is reduced. Secondly, Titanium silicide process clarified that fluorine contamination caused by the gate sidewall etching inhibits the silicidation reaction and accelerates agglomeration. To overcome these problems, a novel Two-step Deposited silicide(TDS) process has been developed. The key point of this process is the deposition and subsequent removal of titanium before silicidation. Based on the research, It is found that novel STI structure by the SEM, in addition to thermally stable silicide process was achieved. We also obtained the decrease threshold voltage value of the channel edge. resulting in the better improvement of the narrow channel effect. low sheet resistance and stress, and high threshold voltage. Besides, sheet resistance and stress value, rms(root mean square) by AFM were observed. On the electrical characteristics, low leakage current and trap density at the Si/SiO$_2$were confirmed by the high threshold voltage sub 0.1${\mu}{\textrm}{m}$ gate oxide.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.19 no.3
• /
• pp.274-280
• /
• 1986

Velocity variability of Masan Inlet in the northernpart of Chinhae Bay is studied on the basis of the cross-sectional net velocity distributions and its root-mean-square. They were calculated during three consecutive cycles at spring tide as well as two cycles at near tide with precipitations in June and July 1985. During the spring tide, net ebb flow take place in the western channel while net flood flow in the eastern channel of the cross-section. On the contrary, the direction of both net flows during the neap tide with precipitations is reversed. R.M.S. isotachs show that the highest velocity is 15 cm/sec at spring tide and 10.3 cm/sec at neap tide, and the greatest velocity is persistently found at the surface layer of the western channel of the cross-section at each tidal cycle. It is shown that the major part of constituents of the constant flow in the Inlet is the tidal residual current. The density-driven current, however, plays an important role afer the heavy precipitations.

• Journal of Plant Biotechnology
• /
• v.43 no.1
• /
• pp.110-118
• /
• 2016

We compared germination efficiency for somatic embryos (SE) of Liriodendron tulipifera using semi-solid (SS), temporary immersion bioreactors (TIB), and continuous immersion bioreactors (CIB) to produce vigorous plants. The bioreactors were designed to be immersed in liquid media with plantlets with an adjustable immersion time. TIB and CIB improved germination rates up to 80.86% and 95.21%, respectively, however, CIB produced more hyperhydric plantlets than TIB. The height of plantlets in TIB was significantly higher than for those in CIB. Fresh weights of plantlets grown in CIB of were significantly lower than for those grown in TIB. The lowest chlorophyll concentration was found in in vitro plantlets from CIB. We examined abnormally developed leaves, stems, and apical zones of in vitro plantlets that were produced in CIB. Among the three types, SS showed the highest stomatal density and the shortest stomatal length in in vitro plantlets. After acclimatization, plants from CIB exhibited the lowest values in biomass, such as height, root collar diameter, leaf fresh weight, leaf length, leaf width, petiole length, petiole diameter, and leaf area. Photosynthesis and transpiration rates of ex vitro plants were not significantly different among the three culture types, but stomatal conductance was higher in TIB than in the SS and CIB. Therefore, the results suggest that TIB is the preferable bioreactor to improve in vitro plantlet regeneration of L. tulipifera. TIB-originated plants showed higher growth rate than SS and CIB after transferring to soil.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2012.02a
• /
• pp.466-468
• /
• 2012

Amorphous InGaZnO (${\alpha}$-IGZO) thin-film transistors (TFTs) are are very promising due to their potential use in thin film electronics and display drivers [1]. However, the stability of AOS-TFTs under the various stresses has been issued for the practical AOSs applications [2]. Up to now, many researchers have studied to understand the sub-gap density of states (DOS) as the root cause of instability [3]. Nomura et al. reported that these deep defects are located in the surface layer of the ${\alpha}$-IGZO channel [4]. Also, Kim et al. reported that the interfacial traps can be affected by different RF-power during RF magnetron sputtering process [5]. It is well known that these trap states can influence on the performances and stabilities of ${\alpha}$-IGZO TFTs. Nevertheless, it has not been reported how these defect states are created during conventional RF magnetron sputtering. In general, during conventional RF magnetron sputtering process, negative oxygen ions (NOI) can be generated by electron attachment in oxygen atom near target surface and accelerated up to few hundreds eV by self-bias of RF magnetron sputter; the high energy bombardment of NOIs generates bulk defects in oxide thin films [6-10] and can change the defect states of ${\alpha}$-IGZO thin film. In this paper, we have confirmed that the NOIs accelerated by the self-bias were one of the dominant causes of instability in ${\alpha}$-IGZO TFTs when the channel layer was deposited by conventional RF magnetron sputtering system. Finally, we will introduce our novel technology named as Magnetic Field Shielded Sputtering (MFSS) process [9-10] to eliminate the NOI bombardment effects and present how much to be improved the instability of ${\alpha}$-IGZO TFTs by this new deposition method.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.16 no.12S
• /
• pp.1187-1194
• /
• 2003

A BCl$_3$/Ne plasma chemistry was used to etch Ga-based (GaAs, AIGaAs, GaSb) and In-based (InGaP, InP, InAs and InGaAsP) compound semiconductors in a Planar Inductively Coupled Plasma (ICP) reactor. The addition of the Ne instead of Ar can minimize electrical and optical damage during dry etching of III-V semiconductors due to its light mass compared to that of Ar All of the materials exhibited a maximum etch rate at BCl$_3$ to Ne ratios of 0.25-0.5. Under all conditions, the Ga-based materials etched at significantly higher rates than the In-based materials, due to relatively high volatilities of their trichloride etch products (boiling point CaCl$_3$ : 201 $^{\circ}C$, AsCl$_3$ : 130 $^{\circ}C$, PCl$_3$: 76 $^{\circ}C$) compared to InCl$_3$ (boiling point : 600 $^{\circ}C$). We obtained low root-mean-square(RMS) roughness of the etched sulfate of both AIGaAs and GaAs, which is quite comparable to the unetched control samples. Excellent etch anisotropy ( > 85$^{\circ}$) of the GaAs and AIGaAs in our PICP BCl$_3$/Ne etching relies on some degree of sidewall passivation by redeposition of etch products and photoresist from the mask. However, the surfaces of In-based materials are somewhat degraded during the BCl$_3$/Ne etching due to the low volatility of InCl$_{x}$./.