• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.6
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• pp.80-87
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• 2018

In recent years, due to the spread of various renewable energy power sources and the pursuit of high efficiency and low-power consumption, not only trends in the electric power industry but also the consumption, control methods, and characteristics are diversified. However, in this diversified electric power industry, the fuse (which is the core part responsible for safety) has not developed significantly in classical operation mode, and thus, fires continue to occur. In this paper, the effects of low melting-point metal plating and high melting-point metal plating on operating characteristics and IT curve movement of the fuse are investigated in a cartridge fuse, which is a classic fuse manufacturing method. The effects of plating on the thickness of the fuse are investigated, and various operating characteristics of the fuse are implemented. In addition, it is suggested that the plating of the low melting-point metal moves the rated current line of the fuse to a low rating, and moves operating characteristics to characteristics of delay operation. It is possible to design various operating characteristics using this characteristic.

• Macromolecular Research
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• v.8 no.1
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• pp.12-18
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• 2000

Six aromatic polyesters with ether-linkages were prepared from 4,4'-oxybis(benzoic acid) and naphthalenediol (ND) isomers which were 1,4-, 1,5-, 1,6-, 2,3-, 2,6- and 2,7-derivatives. The solution viscosity numbers ranged from 0.23 to 0.65 dL/g. The glass transition temperatures ranged from 142 to 179$\^{C}$. The initial decomposition temperatures were all above 400$\^{C}$, and the residue weights at 600$\^{C}$ were in the range of 50-64%. Only the polyesters derived from 1,5- and 2,6-NDs, which have a linear linking mode, were found to be semicrystalline and could form thermotropically nematic phase. Multiple melting phenomena and annealing of the polyester derived from 1,5-ND and related polymers are described. The experimental results show that the polyester derived from 1,4-ND of linear shape was amorphous and non-liquid crystalline. Particularly, the polyester derived from 2,3-ND could form a smectic mesophase as banana-shaped molecules, and this is ascribed to the C/sub_2v/ symmetry where highly kinked molecules are packed in the same direction.

• Proceedings of the International Microelectronics And Packaging Society Conference
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• 2004.09a
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• pp.93-99
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• 2004

At present, LG Electronics pushes ahead to eliminate the Pb(Lead) -a hazardous material- from all products. Especially, we have performed to select the optimum standard composition of lead free alloy for the application to products for about 3 years from 2000. These days, we have the chance for applying to the mass-production. This project constructed the system for applying the lead free solders on consumer electronic products, which is one of the major products of the LG Electronics. To select the lead free solders with corresponding to the product features, we have passed through the test and applied with Sn-3.0Ag-0.5Cu alloy system to our products, and for the application to the high melting temperature composition, we secured the thermal resistance of the many parts and substrate and optimized the processing conditions. We have operated the temperature cycling test and the high temperature storage test under the standards to confirm the reliability of the products. On these samples, we considered the consequence of our decision by the operating test. For the long life time of the product, we have operated the temperature cycling test at $-45^{\circ}C-+125^{\circ}C$, 1 cycle/hour, 1000 cycles. Also we have tested the tin whisker growth about lead free plating on lead finish. We have analyzed with the SEM, EDS and any other equipment for confirming the failure mode at the joint and the tin whisker growth on lead free finish.

• Bulletin of the Korean Chemical Society
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• v.25 no.4
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• pp.539-544
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• 2004

The ability of protoberberine alkaloids, berberine and berberrubine, to act as topoisomerase II poisons is linked to the anti-cancer activity. Minor alterations in structure have a significant effect on their relative activity. Berberine, which has methoxy group at the 19-position, is significantly less potent than berberrubine. Several observations support non-specific binding to HP14 by the berberine: (i) nonspecific upfield changes in $^1H$ chemical shift for protons of the berberine; (ii) the broadening of imino protons of HP14 upon binding of the berberine; (iii) very small increases in duplex melting temperature in the presence of the berberine. Our results reveal that substitution of a hydroxyl group to a methoxy group on the 19-position, thereby converting the berberrubine to the berberine is associated with a non-specific DNA binding affinity and a reduced topoisomerase II poisoning. The presence of a bulky 19-methoxy substituent decreases intercalating properties of berberine and makes it inactive as topoisomerase II poison.

• Bulletin of the Korean Chemical Society
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• v.30 no.9
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• pp.1973-1977
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• 2009

In the present study, at first, 2,4-Dihydroxy Salophen (2,4-DHS), has been synthesized by combination of 1, 2-diaminobenzene and 2,4-dihydroxybenzaldehyde in a solvent system. This ligand containing meta-quinone functional groups were characterized using UV-Vis and IR spectroscopies. Subsequently, the interaction between native calf thymus deoxyribonucleic acid (ct-DNA) and 2,4-DHS, was investigated in 10 mM Tris/HCl buffer solution, pH 7.2, using UV-visible absorption and fluorescence spectroscopies, thermal denaturation technique and viscosity measurements. From spectrophotometric titration experiments, the binding constant of 2,4-DHS with ct-DNA was found to be (1.1 ${\pm}\;0.2)\;{\times}\;10^4\;M^{-1}.$ The fluorescence study represents the quenching effect of 2,4-DHS on bound ethidium bromide to DNA. The quenching process obeys linear Stern-Volmer equation in extended range of 2,4-DHS concentration. Thermal denaturation experiments represent the increasing of melting temperature of DNA (about 3.5 ${^{\circ}C}$) due to binding of 2,4-DHS. These results are consistent with a binding mode dominated by interactions with the groove of ct-DNA.

• Proceedings of the Korean Vacuum Society Conference
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• 1999.07a
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• pp.171-171
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• 1999

We studied the charge redistribution in the Pt-M (M=Cu, Co) alloys by X-ray Absorption Near Edge Spectroscopy(XANES) and X-ray Photoelectron Spectroscopy(XPS). These analysis tools provide us information about the charge transfer in the valence band of intermetallic bonding. The samples were prepared by arc-melting method. After annealing this samples in vacuum for several hours, we cold get the ordered samples, which were confirmed with XRD analysis. the core and valence level energy shift in these system were investigated by Mg $K\alpha$(1253.6eV) x-ray source for Pt-Co alloys and monochromatized Al $K\alpha$ (1486.6eV) for Pt-Cu alloys. Pt L2, L3-edge, and Cu, Co K-edge XANES spectra were measured with the total electron-yield mode detector at the 3Cl beam line of the PLS (Pohang light source0. from the changes of White line (WL) area and the core level shifts of the each metal sites, we can obtain the information about the electrons participating in the intermetallic bonding of the Pt-Cu and Pt-Co alloys.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.28 no.8
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• pp.75-81
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• 2014

It has been widely accepted that open phase may separate one of the power lines from power supply which is mainly caused by fuse melting, malfunction for source circuit breaker, contact failure, and disconnection under normal operating conditions, and is considered a kind of failure mode during disconnection of neutral wires as well. When open phase occurs, unequal voltage between phase might happen in the unbalanced load connected each phase, and further, depending on conditions of load, malfunction by providing low voltage. Moreover, load could be burned or overheated with overvoltage, which, in turn, can be a contributor to starting fires. Accordingly, in order to clearly overcome these problems, the current study aims to introduce the theory of uninterruptible power open phase compensation device, meaning that unbalanced power automatically restores balanced power and provides continuously the power supply without blackout, and verify it through simulation and experiments.

• Journal of the Korean Society of Propulsion Engineers
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• v.22 no.4
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• pp.55-60
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• 2018

The thermal property is one of the most important characteristics in the field of energetic materials. Because energy materials release decomposition heat, differential scanning calorimetry (DSC) is frequently used for thermal analysis. However, thermodynamic events, such as melting can interfere with DSC kinetic analysis. In this study, we use isothermal mode for DSC measurement to avoid thermodynamic issues. We also merge accelerating rate calorimetry(ARC) data with DSC data to obtain a robust prediction results for small scale samples and for large scale samples as well. For the thermal property prediction, advanced kinetics and technology solutions(AKTS) programs are used.

• Proceedings of the Korean Vacuum Society Conference
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• 2000.02a
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• pp.164-164
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• 2000

Since Au-Pt alloys have various atomic structures depending upon composition and annealing temperature, it is very interesting to investigate the electronic structures of alloys. We studied the changes of the electronic structure I the Au-Pt alloys by x-ray absorption near edge spectroscopy (XANES). Two kinds of Au-Pt alloy samples were prepared by arc melting methods and ion-beam-mixing technique. The Pt L2, 3-edge and Au L2, 3-edge X-ray absorption spectra (XPS) were measured with the electron yield mode detector at the 3C1 beam line of the Pohang Light Source (PLS). It was found that there was a substantial decrease in the area of the Pt L2, 3 white lines compared with that of pure Pt. The observed decrease in white line area was attributed to an increase in the number of pure Pt. The observed decrease in white line area was attributed to an increase in the number of 5d-electrons at the Pt site upon alloy formation. However, the Au L2, 3 edge spectra for Au-Pt alloys are all similar to that of pure Au. This implies that the 5d hole count of Au is not changed by alloy formation with Pt.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.7 no.2
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• pp.196-208
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• 1997

This study was performed to estimate quartz contents in the both bulk and airborne dust samples and to determine particle size distribution of airborne dust from the selected foundry operations. Total dust samples were collected by a 37mm cassette and respirable by a 10 mm nylon cyclone. Particle size distributions were determined by a Marple's 8-stage cascade impactor at the melting, molding, shakeout and finishing operations. The presence of elements in the dust samples were confirmed by the scanning electron microscopy equipped with the energy dispersive x-ray spectrometry. The quartz contents were estimated using the intensity of the absorption peak of quartz at 799 cm-l by the Fourie Transformed Infrared Spectroscopy (FTIR). The results were as follows: 1. The analysis of data from cascade Impactor showed bimodal distributions of particle size at the melting, molding and shakeout operations. Mass median aerodynamic diameters for the distributions determined by histogram were $0.48-1.65{\mu}m$ for small and $13.43-19.58{\mu}m$ for large modes. In the dust samples collected at the finishing operations, however, only a large mode of $18.89{\mu}m$ was found. 2. The percentages of total to respirable dust concentration calculated from the impactor data ranged from 42 % to 66 %. The average concentrations of respirable dust by cyclone were $0.85-1.28mg/m^3$ collected from the workers, and were $0.23-0.56mg/m^3$ from the areas surveyed. Dust concentrations of personal samples were statistically significantly higher than those of area samples. The highest dust concentration was obtained from the personal samples of the finishing operation. 3. The mean percentages of silicon and oxygen estimated by SEM-EDXA in the bulk samples ranged from 35.83 % to 36.02 % and from 39.93 %-41.64 %, respectively. 4. The average quartz contents estimated by FTIR in the respirable dust from personal samples ranged from 4.32 % to 5.36 % and 4.54 % to 4.70 % in the bulk samples. No statistical difference of quartz content was found between foundry operations. In this study, quartz content was quantified by FTIR. Although no statistically significant difference in quartz content between airborne and bulk, samples and between different foundry operations was found, it is recommended that quartz content in the individual sample of respirable dust be analyzed and the results be used either to select an applicable quartz limits or to calculate the exposure limit. Further studies, however, are needed to compare the results by FTIR and XRD since it is reported that the quartz content determined by FTIR is different from that by XRD.