• Proceedings of the KIEE Conference
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• 2003.11a
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• pp.379-381
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• 2003

The sharing of common corridors by electric power transmission lines and pipelines is becoming more common place. However, such corridor sharing can result in undesired coupling of electromagnetic energy from the power lines to the near facilities. This causes induced voltages on underground metallic pipelines due to the power line currents. This could cause AC corrosion in the pipeline, which could in turn lead to disastrous accidents, such as gas explosion or oil leakage. This paper investigates for the limitation of induced voltage on the buried metal structures which is used in the inside and outside of the country. And then we measure the earth resistance and leakage current of 22.9kV distribution lines and pipe to soil potential of near pipelines in Seoul Korea. Hereby we can see the leakage current flowing through the earthing electrode have an effect on near pipelines.

• Journal of Astronomy and Space Sciences
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• v.24 no.3
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• pp.227-234
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• 2007

A comet that passes extremely close to the Sun at perihelion is called a sungrazing comet (of sungrazer). Around 1270 sungrazing comets have been discovered on coronagraph images from the SOHO (SOlar and Heliospheric Observatory) spacecraft since 1996 up to April, 2007. The major groups orbiting around the Sun in similar orbits are named as Kreutz, Meyer, Marsden, and Kracht 1&2 families. About 85% of SOHO comets belong to the Kreutz family with perihelion on distances of less than about $2{\sim}3R_{\bigodot}$. The distributions of perihelia and the orbital elements of SOHO sungrazing comets are analyzed. We investigated closely spaced pairs and clusters in the orbital element space. Here, we suggest three prospective groups of the sungrazing cornets: [(C/2000 Y6, C/2000 Y7), (C/2000 V4, C/2001 T5), (C/2003 H6, C/2003 H7)].

• Korean Journal of Crystallography
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• v.18 no.1_2
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• pp.1-6
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• 2007

An Organometallic compound, $C_{16}H_{35}B_{10}IrS_2Si$, was synthesized from o-carborane, $Cp^*Ir(S_2C_2B{10}H_{10})$, and $Me_3SiCHN_2$. The molecular structure of this complex has been determined by X-ray diffraction. Crystallographic data : monoclinic, space group $P2_1/n$, $a=10.1986(12)\;{\AA}$, $b=14.834(5)\;{\AA}$, $c=17.139\;{\AA}$, ${\beta}=92.24(2)^{\circ}$, Z=4, $V=2591.0(14)\;{\AA}^3$. The structure was solved by direct methods and refined by full-matrix leat-squares methods to give a model with a reliability factor R=0.053 for 5080 reflections.

• Bulletin of the Korean Chemical Society
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• v.26 no.12
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• pp.1981-1985
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• 2005

Kinetic studies have been performed for alkaline hydrolysis of a series of [(methoxy)(p-substituted styryl)carbene]pentacarbonyl chromium(0) complexes ($(CO)_5$Cr=$C(OCH_3)CH=CHC_6H_4X$, X = p-$OCH_3$, p-$CH_3$, H, p-Cl, p-$NO_2$). Second-order rate constants $(k_{{OH}^-})$ for the alkaline hydrolysis in 50% acetonitrile-water(v/v) were determined spectrophotometrically at various temperatures. At a low pH region (pH < 7.5), the observed rate constant $(k_{obs})$ remained constant with a small value, while in a high pH region (pH > 9.5), $k_{obs}$ increases linearly with increasing the pH of the medium. The second-order rate constants $(k_{{OH}^-})$ increase as the substituent X changes from a strong electron donating group to a strong electron withdrawing group. The Hammett plot obtained for the alkaline hydrolysis is consisted of two intersecting straight lines. The nonlinear Hammett plot might be interpreted as a change in the rate-determining step. However, the fact that the corresponding Yukawa-Tsuno plot is linear with $\rho$ and r values of 0.71 and 1.14, respectively indicates that the nonlinear Hammett plot is not due to a change in the rate-determing step but is due to ground-state stabilization through resonance interaction. The positive $\rho$ value suggests that nucleophilic attack by $OH^-$ to form a tetrahedral addition intermediate is the rate-determining step. The large negative ${\Delta}S^\neq$ value determined in the present system is consistent with the proposed mechanism.

• Journal of Embryo Transfer
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• v.32 no.3
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• pp.249-255
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• 2017

In this experiment, we determined the effect of curcumin supplementation in freezing buffer for miniature pig sperm cryopreservation. Each ejaculate was diluted with modified Modena B extender and mixed with lactose-egg yolk (LEY extender, 80% v/v lactose solution [310 mM], 20% v/v egg yolk, and $100{\mu}g/mL$ kanamycin sulfate) and LEY-glycerol Orvus ES Paste (LEYGO, 89.5% v/v LEY, 5% v/v glycerol, 1.5% v/v Orvus ES Paste), 100 mM trehalose supplemented with 0, 10, 50, 100, and $500{\mu}M$ of curcumin from turmeric, respectively. Following equilibration, the 0.5 mL French straws were frozen and plunged into $LN_2$ tank for 7 days at least. Sperm parameter and oxidative byproducts were determined by the computer assisted sperm motility analysis (CASA) and fluorescence-activated cell sorting (FACS) as compared with each groups. Supplementation of curcumin had no effect on sperm motility, progressive motility and curvilinear velocity. However, average-path velocity and straight-line velocity were significantly higher in $10{\mu}M$ curcumin group ($100.9{\pm}8.8{\mu}m/s$, $61.7{\pm}2.9{\mu}m/s$, respectively) than control group ($77.8{\pm}3.9{\mu}m/s$, $46.4{\pm}3.0{\mu}m/s$, respectively) (p < 0.05). In addition, the level of the O2 radical and H2O2 were comparatively decreased in curcumin groups by evaluation of ethidium and DCF fluorescence. According to the results, curcumin can improve sperm kinetic variables and alleviate ROS induced cryoinjury to pig sperm.

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

• Nuclear Engineering and Technology
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• v.48 no.1
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• pp.164-168
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• 2016

Lean duplex stainless steels with 0.087 wt.% gadolinium (Gd) were inert arc-melted and cast in molds of size $10mm{\times}10mm{\times}20mm$. The micro-hardnesses of the rolling direction (RD), transverse direction (TD) and short transverse (ST) direction were $258.5H_V$, $292.3H_V$, and $314.7H_V$, respectively. A 33% cold rolled specimen had the crystallographic texture that (100) pole was mainly concentrated to the normal direction (ND) and (110) pole was concentrated in the center of ND and RD. The corrosion potential and corrosion rate in artificial seawater and $0.1M\;H_2SO_4$ solution were in the range of $105.6-221.6mV_{SHE}$, $0.59-1.06mA/cm^2$, and $4.75-8.25mV_{SHE}$, $0.69-1.68mA/cm^2$, respectively. The friction coefficient and wear loss of the 0.087 w/o Gd-lean duplex stainless steels in artificial seawater were about 67% and 65% lower than in air, whereas the wear efficiency was 22% higher. The corrosion and wear behaviors of the 0.087 w/o Gd-lean duplex stainless steels significantly depended on the Gd phases.

• Korean Journal of Crystallography
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• v.5 no.1
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• pp.1-6
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• 1994

Two possible space groups of the comfound, VP6N3018C24H:60, are: P 1, a=14.022(1), b=12.644(2), c= 12.640(1)A, a=8038(1), B=102.12(1), r=102.16(1), V=2124.1A3, Z=2, μ=0.47cm-1, d=1.46g/cm3, R=0.083 for 3350 independent reflections with Fo>4o IFI, and C2/c, a=19.32(2), b=16.32(2), c=14.02(1)A, B=105.98(5), β=105.98(5), V=4248.2A3, Z=4 R=0.083 for 1590 independent reflections with Fo>4c IFoI . In the space group P T, there are two monlecules in a unit cell. Vanadium atoms in the two monlecules occupy the two different special positions such that the complete monlecules are accomplished by the two independent center of symmetry. Therefore two different half molecules of bis(trimetaphosphate)vanadate and three molecules of tetraethylammonium are the asymmetric unit in a unit cell. In the space group C2/c, however, the vanadium atom is located at a special position with centrosymmetry, and a two-fold symmetry axis passes through C2/c, N2 and C25 atoms. Therefore the asymmrtic unit in a unit cell consists of a half molecule of bis(trimetaphosphate)vanadate and one and a half molecules of tetraethylammonium. All the molecular conformations in both space groups are very similar: six oxygen atoms coordinated to a vanadium atom in the bi s(trimetaphosphate)vanadate molecule form an octahedron and the four carbon atoms bonded to a nitrogen atom in the tetraethylammonium molecule are disordered so that the eight carbon atoms around nitrogen atom exhibit an irregular dodecahedral form.

• Journal of Dental Rehabilitation and Applied Science
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• v.22 no.4
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• pp.349-365
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• 2006

State of problem : A number of investigation about increase of surface area via various surface treatments and modification of surface constituent have been carried out. Purpose : The surface characteristics and stability of implants treated with anodic oxidation, fluoride ion incorporation, and groups treated with both methods were evaluated. Material and method : Specimens were divided into six groups, group 1 was the control group with machined surface implants, groups 2 and 3 were anodic oxidized implants (group 2 was treated with 1M $H_2SO_4$ and 185V, group 3 was treated with 0.25M $H_2SO_4$ and $H_3PO_4$ and 300V). Groups 4, 5 and 6 were treated with fluoride. Group 4 was machined implants treated with 0.1% HF, and groups 5 and 6 were groups 2 and 3 treated with 10% NaF respectively. Using variable methods, implant surface characteristics were observed, and the implant stability was evaluated on rabbit tibia at 0, 4, 8 and 12 weeks. Result : 1. In comparison of the surface characteristics of anodic oxidized groups, group 2 displayed delicate and uniform oxidation layer with small pore size containing Ti, C, O and showed mainly rutile, but group 3 displayed large pore size and irregular oxidation layer with many crators. 2. In comparison of the surface characteristics of fluoride treated groups 4, 5, 6 and non-fluoride treated groups 1, 2, 3, the configurations were similar but the fluoride treated groups displayed rougher surfaces and composition analysis revealed fluoride in groups 4, 5, 6. 3. The fluoride incorporated anodic oxidized groups showed the highest resonance frequency values and removal torque values, and the values decreased in the order of anodic oxidized groups, fluoride treated group, control group. 4. According to implant stability tests, group 2 and 3 showed significantly higher values than the control group (P<.05). The fluoride treated groups showed relatively higher values than the non fluoride treated groups and there were significant difference between group 4 and group 1 (P<.05). Conclusion : From the results above, it can be considered that the anodic oxidation method is an effective method to increase initial bone stability and osseointegration and fluoride containing implant surfaces enhance new bone formation. Implants containing both of these methods should increase osseointegration, and reduce the healing period.

• Journal of Dental Anesthesia and Pain Medicine
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• v.16 no.4
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• pp.295-302
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• 2016

Background: Reactive oxygen species play critical roles in homeostasis and cell signaling. Dexmedetomidine, a specific agonist of the ${\alpha}2$-adrenoceptor, has been commonly used for sedation, and it has been reported to have a protective effect against oxidative stress. In this study, we investigated whether dexmedetomidine has a protective effect against $H_2O_2$-induced oxidative stress and the mechanism of $H_2O_2$-induced cell death in normal human fetal osteoblast (hFOB) cells. Methods: Cells were divided into three groups: control group-cells were incubated in normoxia without dexmedetomidine, hydrogen peroxide ($H_2O_2$) group-cells were exposed to $H_2O_2$ ($200{\mu}M$) for 2 h, and Dex/$H_2O_2$ group-cells were pretreated with dexmedetomidine ($5{\mu}M$) for 2 h then exposed to $H_2O_2$ ($200{\mu}M$) for 2 h. Cell viability and apoptosis were evaluated. Osteoblast maturation was determined by assaying bone nodular mineralization. Expression levels of bone-related proteins were determined by western blot. Results: Cell viability was significantly decreased in the $H_2O_2$ group compared with the control group, and this effect was improved by dexmedetomidine. The Hoechst 33342 and Annexin-V FITC/PI staining revealed that dexmedetomidine effectively decreased $H_2O_2$-induced hFOB cell apoptosis. Dexmedetomidine enhanced the mineralization of hFOB cells when compared to the $H_2O_2$ group. In western blot analysis, bone-related protein was increased in the Dex/$H_2O_2$ group. Conclusions: We demonstrated the potential therapeutic value of dexmedetomidine in $H_2O_2$-induced oxidative stress by inhibiting apoptosis and enhancing osteoblast activity. Additionally, the current investigation could be evidence to support the antioxidant potential of dexmedetomidine in vitro.