• Journal of The Korean Astronomical Society
• /
• v.19 no.2
• /
• pp.69-89
• /
• 1986

The global morphology and geometric parameters of 39 barred galaxies are investigated, by using isophote map and isodensity tracings obtained from detailed surface photometry with the Kiso V-band plates. The observed results are as follows: i) There is no strong indication that the ratio of bar length to disk size is correlated with Hubble type, except that the largest bars appear in the SBb galaxies. ii) The mean value of axial ratios of bars is $2.0{\pm}0.4$ and there is a trend that early type galaxies have smaller axial ratios than late type galaxies. iii) About 15% of early type barred galaxies(Sb0-SBb) have triaxial bulges.

• Journal of the Korean Vacuum Society
• /
• v.6 no.4
• /
• pp.354-358
• /
• 1997

Crystal properties of wurtzite GaN films grown on $Al_2O_3$(0001) substrates under various nitrogen pressure and plasma power by electron cyclotron resonance molecular beam epitaxy were investigated by full width at half maximum of X-ray diffraction peak and scanning electron microscope. It was found that the nitrogen pressure has a large effect on the FWHM value of XRD, and the GaN film grown under the optimum nitrogen pressure contains high density of dislocations. These results suggest that the crystal quality is sensitive to the plasma source conditions and that the relaxation of stress depends of V/III ratio. However, substrate-surface nitridation has little effect on the relaxation of misfit stress.

• Journal of the Korean Chemical Society
• /
• v.18 no.4
• /
• pp.267-271
• /
• 1974

The tetradentate schiff base, N,N'-bis(salicylaldehyde)-ethylene diimine has been reacted with a series of Mo(IV), Mo(V), Mo(IV), and Mo(III) oxidation states to form new Complexes; $[MoO_2(C_{16}H_{14}O_2N_2)], (MoO(C_{16}H_{14}O_2N_2)]_2O, (Mo(SCN)(C_{16}H_{14}O_2N_2)]_2O, and (Mo(H_2O)(C_{16}H_{14}O_2N_2)]_2O.$ These complexes have hexa coordinated configurations and the mole ratio of these ions to the ligand was 1:1. These complexes have been identified by visible spectra, infrared specra, T.G.A., D.T.A., and elemental analysis.

• Journal of Forest and Environmental Science
• /
• v.34 no.6
• /
• pp.472-480
• /
• 2018

This study was conducted to estimate carbon storage in Quercus mongolica stands based on stand age class, and to provide basic data on the carbon balance of broad-leaved forests of Korea. The research was conducted at the experimental forest of Kangwon National University, Hongcheon-gun County, Gangwon-do Province, Korea. Three plots were set up in each of three Q. mongolica forest stands (III, V, and VII) to estimate the amount of carbon stored in Q. mongolica aboveground vegetation, coarse woody debris (CWD), organic layer, mineral soil, and litterfall. The carbon storage of the aboveground vegetation increased with an increase in stand age, while the carbon storage ratio of stems decreased. The carbon storage of the organic layer, CWD, and litterfall did not show any significant differences among age classes. In addition, the carbon concentration and storage in the forest soils decreased with depth, and there were no differences among age classes for any soil horizon. Finally, the total carbon storage in the III, V, and VII stands of Q. mongolica were 132.2, 241.1, and $374.4Mg\;C\;ha^{-1}$, respectively. In order to predict and effectively manage forest carbon dynamics in Korea, further study on deciduous forests with other tree species in different regions will be needed.

• Journal of the Korean Chemical Society
• /
• v.33 no.2
• /
• pp.192-202
• /
• 1989

Tetradentate schiff bases cabalt (II) complexes; Co(SED) and Co(ο-BSDT) were synthesized and these complexes allowed to reaction with dry oxygen to form oxygen adduct cobalt(III) complexes such as $[Co(o-BSDT)(DMSO)]_2O_2,\;[Co(SED)(Py)]_2O_2\;and\;[Co(o-BSDT)(Py)]_2O_2$ in DMSO and pyridine solutions. It has been found that the oxygen adduct cobalt(III) complexes have hexacoordinated octahedral configuration with tetradentate schiff base cobalt(II), DMSO or pyridine and oxygen, and the mole ratio of oxygen to cobalt(II) complexes are 1:2. The redox processes, were investigated for Co(SEDT) and Co(ο-BSD) complexes in 0.1M TEAP-DMSO and 0.1M TEAP-pyridine by cyclic voltammetry with glassy carbon electrode. As a result the redox processes of Co(II)/Co(III) and Co(II)/Co(I) found to be reversible or quasi-reversible for non uptake oxygen complexes but oxygen adduct complexes found to be irreversible processes and reaction processes of oxygen for oxygen adduct complexes are quasi-reversible process, the potential range was $E_{pc}=-0.85{\sim}-1.19V\;and\;E_{pa}=-0.74{\sim}-0.89V$.

• Journal of the Korean Chemical Society
• /
• v.33 no.3
• /
• pp.295-303
• /
• 1989

Tetradentate Schiff base cobalt(II) complex; Co(SND) and Co(SOPD) were synthesized, and these complexes were allowed to react with dry oxygen to form oxygen adducts cobalt(III) complexes such as $[Co(SND)(Py)]_2O_2$ and $[Co(SOPD)(Py)]_2O_2$ in pyridine. These complexes have been identified by IR specta, T.G.A., magnetic susceptibilities measurements and elemental analysis. It has been found that the oxygen adducts coblat(III) complexes have hexacoordinated octahedral configuration with tetradentate Schiff base cobalt(II), pyridine and oxygen, and the mole ratio of oxygen to cobalt(II) complexes are 1;2. The redox reaction processes of $Co(SND)(Py)_2$ and $Co(SOPD)(Py)_2$ complexes were investigated by cyclic voltammetry with glassy carbon electrode in 0.1M TEAP pyridine. The result of redox reaction processes of Co(III)/Co(II) and Co(II)/Co(I) for $Co(SND)(Py)_2$ and $Co(SOPD)(Py)_2$ complexes are reversible or quasi reversible process but oxygen adducts complexes are irreversible processes. Redox process for oxygen of oxygen adducts complexes was quasi reversible and redox range of potential was $E_{pc}\;=\;-0.96{\sim}-1.03V$ and $E_{pa}\;=\;-0.78{\sim}-0.80V.$

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.14 no.11
• /
• pp.5930-5938
• /
• 2013

The sigmoid functionally graded mateiral(S-FGM) theory is reformulated using the nonlocal elatictiry of Erigen. The equation of equilibrium of the nonlocal elasticity are derived. This theory has ability to capture the both small scale effects and sigmoid function in terms of the volume fraction of the constituents for material properties through the plate thickness. Navier's method has been used to solve the governing equations for all edges simply supported boundary conditions. Numerical solutions of biaxial buckling of nano-scale plates are presented using this theory to illustrate the effects of nonlocal theory and power law index of sigmoid function on buckling load. The relations between nonlocal and local theories are discussed by numerical results. Further, effects of (i) power law index, (ii) length, (iii) nonlocal parameter, (iv) aspect ratio and (v) mode number on nondimensional biaxial buckling load are studied. To validate the present solutions, the reference solutions are discussed.

• Journal of Korean Society of Environmental Engineers
• /
• v.28 no.11
• /
• pp.1186-1191
• /
• 2006

Removal efficiency of As(III) through oxidation and adsorption in column reactors was investigated at different ratios of manganese-coated sand(MCS) and iron-coated sand(ICS) : MCS-alone, ICS-alone and both of ICS and MCS. The breakthrough of arsenic immediately occurred from a column reactor with MCS-alone. However, most of the arsenic present in the effluent was identified as As(V) due to the oxidation of As(III) by MCS. While five-times delayed breakthrough of arsenic was observed from a column reactor with ICS-alone. At a complete breakthrough of arsenic, the removed As(III) was 36.1 mg with 1 kg ICS. To find an optimum ratio of ICS and MCS in the column packed with both ICS and MCS, the removal efficiency of As(III) was investigated at three different ratios of ICS/MCS with a fixed amount of ICS. The breakthrough time of arsenic was quite similar in the different ratios ICS/MCS. However, much slower breakthrough of arsenic was observed as the ratio of ICS/MCS decreased. As the ratio of ICS/MCS decreased the concentration of As(III) in the effluent decreased and then showed below 50 ppb at an equal amount of ICS and MCS, suggesting more efficient oxidation of As(III) by greater amount of MCS. When a complete breakthrough of arsenic occurred, the removed total arsenic with an equal amount of ICS and MCS was 68.5 mg with 1 kg of filter material.

• The Journal of Korean Physical Therapy
• /
• v.18 no.3
• /
• pp.37-45
• /
• 2006

Purpose: This study analyzed changes in spinal neuron and action potential of motor unit depending on voluntary contraction on spinal neuron adaptation. Methods: It selected 80 university students in their twenties and divided into experimental groups of 25% MVIC (I), 50% MVIC (II), 75% MVIC (III) and 100% MVIC (IV) depending on maximum voluntary isometric contraction (MVIC) and performed isometric exercise of plantar flexor muscle to each experimental group with given contraction for 20 times. It measured Mmax, H/Mmax, Hmax latency, V/Mmax, V wave latency before and after exercise, compared method and volume of contraction. Results: H/Mmax ratio showed significant difference in comparison among groups (p<0.01) and there was difference in I and IV groups. V/Mmax ratio showed significant difference in comparison among experimental groups (p<0.05) and there was difference in I and IV groups. When voluntary contraction level was maximum, changes were greatest. However, no significantly difference was to Mmax, H latency and V wave latency. Conclusion: These results suggest that amplitude changes of voluntary contraction level, spinal neuron and supra-spinal neuron had a dose connection that the more contraction level, the better central activation seem to decrease highly for a short time.

• Journal of Biosystems Engineering
• /
• v.35 no.2
• /
• pp.100-107
• /
• 2010

This study was conducted to investigate the effects of electric current stimuli and high-voltage electric field treatments on brown rice germination. The brown rice stimulated by electrical current stimuli, functional electrical stimuli of a pulse type, and high-voltage electric field treatments were observed (Type I, II and III). Treatment Type I was a method of semi-soaking brown rice with electric current stimuli of 0.13 V/cm, 0.19 V/cm, and 0.25 V/cm into Petri-dishes for 72 hours. Type II was a method of semi-soaking brown rice with functional electrical stimuli of a pulse type(DC 1 V, 1 Hz, 5%, and duty cycles of 5%, 20%, and 35%) into Petri-dishes for 72 hours. Type III was a method of water-soaking with high-voltage electric field treatments for 60 hours. High-voltage electric field treatments at 15 kV/cm were also conducted for 2.5 min, 7.5 min, and 10 min, respectively. The germination rate and the sprout growth of brown rice germinated by electric current stimuli with 0.13 V/cm, 0.19 V/cm, and 0.25 V/cm were increased by about 10-15% compared with those of the control group. The germination rate and the sprout growth of brown rice germinated by functional electrical stimuli of pulse type(DC 1 V, 1 Hz, 5% duty cycle) were increased by about 10∼15% compared to those of the control group. Also, the best effective treatment among high-voltage electric field treatments was the 10 min group at 15 kV/cm. The germination rate and the sprout growth of brown rice germinated by this treatment of 10 min at 15 kV/cm were increased by about 10∼20% compared to those of the control group. The treatments of electric current stimuli and high-voltage electric field accelerated the germination rate and sprout growth of brown rice by about 10∼15% compared to those of the control group.