• Transactions of the Korean Society of Machine Tool Engineers
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• v.15 no.5
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• pp.1-6
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• 2006

The purpose of this study is to develop to portable near infrared analyzer measuring the sugar content of the fruits on a tree before harvesting ones. The portable near infrared system consists of a tungsten lamp, a coaxial optical fiber bundle and a multi-channel detector, which has 256 pixels and a concave transmission grating. Reflectance NIR spectra of orange were recorded by using a coaxial optical fiber bundle. The spectra were collected over the spectral range $400{\sim}1100nm$. Partial least squares regression(PLSR) was applied for a calibration and validation for determination of sugar contents. The multiple correlation coefficient was 0.99 and standard errors of calibration(SEC) was 0.069 brix. The calibration model predicted the sugar content for validation set with standard errors of prediction(SEP) of 0.092 brix. The sugar content in fruits was successfully quantified using the portable near infrared analyzer.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.24 no.3
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• pp.229-233
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• 2011

Diamond thin films were deposited on pretreated Co cemented tungsten carbide (WC-6%Co) inserts as substrate by microwave plasma chemical vapor deposition (MPCVD) system, equipped with a 915MHz, 30kW generator for generating a large-size plasma. The substrates were pretreated with two solutions Murakami solution $[KOH:K_3Fe(CN)_6:H_2O]$ and nitric solution $[HNO_3:H_2O]$ to etch, WC and Co at cemented carbide substrates, respectively. The deposition experiments were performed at an input power of 10 kW and in a total pressure of 100 torr. The influence of various $CH_4$ contents on the crystallinity and morphology of the diamond films deposited in MPCVD was investigated using scanning electron microscopy (SEM) and Raman spectroscopy. The diamond film synthesized by the $CH_4$ plasma shows a triangle-faceted (111) diamond. As $CH_4$ contents was increased, the thickness of diamond films increased and the faceted planes disappeared. Finally, Faceted diamond changed into nano-crystalline diamond with random crystallinity.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.1322_1323
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• 2009

The $V_{1.85}W_{0.15}O_5$ thin films deposited on Pt/Ti/$SiO_2$/Si substrates by RF sputtering method exhibited fairly good TCR and dielectric properties. It was found that film crystallinity, dielectric properties, and TCR properties were strongly dependent upon the annealing temperature. The dielectric constants of the $V_{1.85}W_{0.15}O_5$ thin films annealed at $400^{\circ}C$ were 38.11, with a dielectric loss of 1%, respectively. Also, the TCR values of the $V_{1.85}W_{0.15}O_5$ thin films annealed at $400^{\circ}C$ were about -3.45%/K.

• Proceedings of the KIEE Conference
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• 2008.10a
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• pp.117-118
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• 2008

The $V_{1.85}W_{0.15}O_5$ thin films deposited on Pt/Ti/$SiO_2$/Si substrates by RF sputtering method exhibited fairly good TCR and dielectric properties. It was found that film crystallinity, dielectric properties, and TCR properties were strongly dependent upon the annealing temperature. The dielectric constants of the $V_{1.85}W_{0.15}O_5$ thin films annealed at $400^{\circ}C$ were 38.11, with a dielectric loss of 1%, respectively. Also, the TCR values of the $V_{1.85}W_{0.15}O_5$ thin films annealed at $400^{\circ}C$ were about -3.45%/K.

• Proceedings of the KIEE Conference
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• 2006.07a
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• pp.603-604
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• 2006

We investigated the effects of oxidizer additive on the performance of Cu-CMP process using commonly used tungsten slurry. According to the CMP removal rates and particle size distribution, and the micro- structures of surface layer as a function of oxidizer contents were greatly influenced by the slurry chemical composition of oxidizers. The difference in removal rate and roughness of copper surface are believed to cause by modification in the mechanical behavior of $Al_{2}O_3$ abrasive particles in CMP slurry.

• Proceedings of the KIEE Conference
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• 2006.07b
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• pp.1269-1270
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• 2006

We investigated the effects of oxidizer additive on the performance of Cu-CMP process using commonly used tungsten slurry. According to the CMP removal rates and particle size distribution, and the micro-structures of surface layer as a function of oxidizer contents were greatly influenced by the slurry chemical composition of oxidizers. The difference in removal rate and roughness of copper surface are believed to cause by modification in the mechanical behavior of $Al_2O_3$ abrasive particles in CMP slurry.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.28 no.11
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• pp.33-41
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• 2014

This paper is research result for a development of sapphire silicon ingot glowing(SSIG) PWM converter system for 80kW 10kA. The system include 3-phase AC-DC diode rectifier of input voltage AC 380V and 60Hz, DC-AC single phase full bridge PWM inverter of high frequency, AC-DC single-phase full wave rectifier using center-tapped of transformer for low voltage 8.0V and large current 10,000A of output specification, tungsten resistor load 0.1[$m{\Omega}$]. PWM switching frequency for IGBT inverter control set 30kHz. The suggested researching contents are designed data sheets of power converter system, PSIM simulation, operating characteristics and analysis results of developed SSIG system. This paper propose

• Proceedings of the KIEE Conference
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• 2006.07c
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• pp.1729-1730
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• 2006

We investigated the effects of oxidizer additive on the performance of Cu-CMP process using commonly used tungsten slurry. According to the CMP removal rates and particle size distribution, and the micro-structures of surface layer as a function of oxidizer contents were greatly influenced by the slurry chemical composition of oxidizers. The difference in removal rate and roughness of copper surface are believed to cause by modification in the mechanical behavior of $Al_{2}O_{3}$ abrasive particles in CMP slurry.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2015.05a
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• pp.107-107
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• 2015

In order to investigate electrochemical behavior and biocompatibility of Co-Cr dental alloy by electrochemical corrosion test and MTT assay, the xCo-25Cr-yW-zNi alloys were used in this study. Samples of Co-Cr-W-Ni alloys were manufactured using arc melting furnace. The microstructure of the alloys was examined by optical microscopy (OM), Field emission scanning electron microscopy (FE-SEM), energy dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), MTT assay, and corrosion test. Corrosion resistance increased slightly as cobalt (Co) content increased. And bioactivity was concerned with nickel (Ni) and tungsten (W). Biocompatibility of Co-Cr alloy depended on Ni and W contents.

• Economic and Environmental Geology
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• v.31 no.4
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• pp.277-290
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• 1998

The purpose of this research is to investigate the dispersion pattern of gold during skarnization and genesis of gold mineralization in the Sangdong skarn deposits. The Sangdong scheelite orebodies are embedded in the Cambrian Pungchon Limestone and limestone interbedded in the Myobong Slate of the Cambrian age. The tungsten deposits are classified as the Hangingwall Orebody, the Main Orebody and the Footwall Orebody as their stratigraphic locations. Recently, the Sangdong granite of the Cretaceous age (85 Ma) were found by underground exploratory drillings below the orebodies. In geochemisty, the W, Mo, Bi and F concentrations in the granite are significantly higher than those in the Cretaceous granitoids in southern Korea. Highest gold contents are associated with quartz-hornblende skarn in the Main Orebody and pyroxene-hornblende skarn in the Hangingwall Orebody. Also Au contents are closely related to Bi contents. This could be inferred that Au skarns formed from solutions under reduced environment at a temperature of $270^{\circ}C$. According to the multiple regression analysis, the variation of Au contents in the Main Orebody can be explained (87.5%) by Ag, As, Bi, Sb, Pb, Cu. Judging from the mineralogical, chemical and isotope studies, the genetic model of the deposits can be suggested as follows. The primitive Sangdong magma was enriched in W, Mo, Au, Bi and volatiles (metal-carriers such as $H_2O$, $CO_2$ and F). During the upward movement of hydrothermal ore solution, the temperature was decreased, and W deposits were formed at limestone (in the Myobong Slate and Pungchon Limestone). In addition, meteoric water influx gave rise to the retrogressive alterations and maximum solubility of gold, and consequently higher grade of Au mineralization was deposited.