• Journal of the Korean institute of surface engineering
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• v.29 no.6
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• pp.745-752
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• 1996

Wear property of plasma spray coating in $Cr_2O_3$ powder manufatured of spray dry method on the aluminum substrate was inspected for the application of piston-ring of automotive enginel. The plama spray coatings were varied with feed rate and particle size. Used the ball-on disc type tribometer, wear volume, friction, surface rougness were investigated. The delamination of the coating layer were observed with SEM. Also the cross-section of wear track were investigated, using optical microscopy. As a result of experiment, wear mechanism was addressed in the various coating process.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.1B
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• pp.56-61
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• 2000

The maximum number of nodes in WDM self healing ring network in limited by several factors including network architecture and ASE noise due to EDFAs at each optical ADM node. In this paper, the maximum node numbers for several protection architectures and bit rates limited by ASE are calculated and compared with the number limited by wavelength numbers. Appropriate design rules can be deduced from these results.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.489-489
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• 2012

The vibrational distribution of $N_2$ (B, v') in after-glows in $N_2$ RF flowing plasma was investigated. The optical emission of the after-glow was studied as function of distance from plasma. In a tube 2.1 cm, the gas pressure varied 8 Torr with 1000sccm nitrogen gas flowing late.. The discharges were excited by two ring-electrode powered by RF 13.56 MHz 100 Watt. $N_2$ (B, v') vibrational distribution was analyzed to see depends of position in after-glow. Dissociation rate of $N_2$ varied showing maximum in the late after-glow region. We studied $N_2$ RF capacitive flowing plasmas and afterglows by emission spectroscopy and by NO titration to determine the density of N-atoms.

• Journal of The Korean Astronomical Society
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• v.31 no.2
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• pp.141-160
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• 1998

We have conducted BV RI CCD surface photometry of three spiral galaxies ESO 598-G009, NGC 1515 and NGC 7456. In order to understand the morphological properties and luminosity distribution characteristics for each galaxy, we derived isophotal map, position angle profile, ellipticity profile, luminosity profile, color profile and color contour map. ESO 598-G009, which has a bright bulge component and a ring, shows a trace of gravitational interaction. NGC 1515 is a spiral galaxy with a bar and dust lane. NGC 7456 shows typical characteristics of a late type spiral galaxy.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.28 no.1
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• pp.85-91
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• 2004

The sapphire wafers for blue light emitting devices were manufactured by the implementation of the surface machining technology based on micro-tribology. This process has been performed by chemical and mechanical polishing process. The sapphire crystalline wafers were characterized by double crystal X-ray diffraction. The sample quality of sapphire crystalline wafer at surfaces has a full width at half maximum of 89 arcsec. The surfaces of sapphire wafer were mechanically affected by residual stress during the polishing process. The wave pattern of optical interference of sapphire wafer implies higher abrasion rate in the edge of the wafer than its center from the Newton's ring.

• Journal of the Korean Chemical Society
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• v.20 no.4
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• pp.295-298
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• 1976

The fact that a reaction between organothioenamine phosphonate and styrene oxide produces a derivative of cyclopropane has been proved by structural identification. This suggests that an anionic oxygen atom from the ring opening of the styrene oxide by nucleophilic attack of thioenamine phosphonate links to the phosphorous atom to from a betaine as an intermediate which is followed by cleavage of the weak P-C bond. The dextrorotatory optical activity of the product showed that the reaction was under the control of steric stability of the benzyl carbon in styrene which leads to the product through a sterically stable pathway.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.37 no.5
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• pp.49-54
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• 2000

We propose a new structure of bidirectional add/drop multiplexer that is a key component to implement bidirectional ring network. The proposed bidirectional add/drop multiplexer is based on fiber Bragg gratings. In experiment, we demonstrate the operation of the proposed bidirectional add/drop multiplexer in optical spectrum domain.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.8
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• pp.1412-1415
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• 2008

A glucose biosensor using a microdisk resonator in polymeric waveguides was developed by observing either the shift in the resonant wavelength or the variation in the optical power. The deformation in the transfer curve of the vertically coupled resonator sensor resulting from the variation in the disk-to-ring coupling, which was incurred by the application of the target analyze, was suppressed. And the refractive index of the polymeric waveguide was devised to closely follow that of the analyze itself for enhancing the sensitivity of the sensor. The sensitivity and measurement range were observed to be respectively 0.14 pm/(mg/dL) and 1500 mg/dL (theoretically up to 4700 mg/dL, for the wavelength shift method and 0.04 dB/(mg/dU and 140 mg/dL the power variation scheme.

• Journal of information and communication convergence engineering
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• v.11 no.2
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• pp.139-146
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• 2013

This paper proposes a new spatial filtering approach for increasing the depth-of-field (DOF) of imaging systems, which is very useful for obtaining sharp images for a wide range of axial positions of the object. Many different techniques have been reported to increase the depth of field. However the main advantage in our method is its simplicity, since we propose the use of purely absorbing beam-shaping elements, which allows a high focal depth with a minimum modification of the optical architecture. In the filter design, we have used the analogy between the axial behavior of a system with spherical aberration and the transverse impulse response of a 1D defocused system. This allowed us the design of a ring-shaded filter. Finally, experimental verification of the theoretical statements is also provided.

• Bulletin of the Korean Chemical Society
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• v.17 no.5
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• pp.433-436
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• 1996

Cobalt(Ⅲ) complexes of trifunctional amino acid and N,N'-diethylethylenediamine-N,N'-di-α-butyrate(deedba), s-cis-[Co(deedba)(L-aa)] (L-aa=S-methyl-L-cysteine, L-aspartic acid, L-glutamic acid) have been prepared from the reaction between the s-cis-[Co(deedba)(Cl2)]- complex and the corresponding amino acid. The amino acids have been found to coordinate through the amine and carboxylate groups. The S-methyl-L-cystene is coordinated not by the sulfur donor atom, but by the nitrogen and oxgen donor atoms, and the L-aspartic and L-glutamic acids are coordinated to the cobalt(Ⅲ) ion via formation of the five-membered glycinate chelate ring. Relatively small optical activity shown by the complexes is due to the chiral center present in the amino acids.