• Journal of the Optical Society of Korea
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• v.19 no.6
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• pp.560-565
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• 2015

We report efficient direct coupling of THz dipole antenna pulses onto air spaced two-wire transmission lines and Teflon covered two-wire lines. The air spaced two-wire lines show TEM mode propagation with very small group velocity dispersion (GVD) and relatively low attenuation. The Teflon covered two-wire lines showed comparatively much higher attenuation and GVD. However, the Teflon covered two-wire lines show a very good guiding property when the lines are curved. Although the lines are circled only 5.0 cm in diameter, there is no additional attenuation compared to straight the lines.

• Restorative Dentistry and Endodontics
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• v.47 no.2
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• pp.16.1-16.9
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• 2022

Objectives: This study compared the cyclic fatigue resistance of One Curve (C wire) and F6 Skytaper (conventional austenite nickel-titanium [NiTi]), and 2 instruments with thermos-mechanically treated NiTi: Protaper Next X2 (M wire) and Hyflex CM (CM wire). Materials and Methods: Ten new instruments of each group (size: 0.25 mm, 6% taper in the 3 mm tip region) were tested using a rotary bending machine with a 60° curvature angle and a 5 mm curvature radius, at room temperature. The number of cycles until fracture was recorded. The length of the fractured instruments was measured. The fracture surface of each fragment was examined with a scanning electron microscope (SEM). The data were analyzed using one-way analysis of variance and the post hoc Tukey test. The significance level was set at 0.05. Results: At 60°, One Curve, F6 Skytaper and Hyflex CM had significantly longer fatigue lives than Protaper Next X2 (p < 0.05). No statistically significant differences were found in the cyclic fatigue lives of One Curve, F6 Skytaper, and Hyflex CM (p > 0.05). SEM images of the fracture surfaces of the different instruments showed typical features of fatigue failure. Conclusions: Within the conditions of this study, at 60° and with a 5 mm curvature radius, the cyclic fatigue life of One Curve was not significantly different from those of F6 Skytaper and Hyflex CM. The cyclic fatigue lives of these 3 instruments were statistically significantly longer than that of Protaper Next.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2000.04a
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• pp.537-542
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• 2000

Wire deflection, surface roughness and roundness were observed on changing discharge time for electrical discharge machining(EDM) of STD-11 in various conditions of thickness. The wire deflection was decreased as increasing discharge time and wire tension. The deflection is the smallest at the speed of wire of 10.6m/min and the water specific resistivity of 5k$\Omega$.cm. The deflection is found to be decreased as increasing dwell time. But if the water pressure is high, it is found not to be changed after the vibration of 4sec. The component of copper(Cu) and zinc(Zn), which is the main material of wire electrode, is observed for rough wire-cutting EDM of STD-11. This phenomena is found to be similar in spite of the change of EDM energy level. But it will be improved by changing the material and the shape of wire. The roundness of middle is found to be worse than that of upper and it is increased as the thickness of material is increased.

• Transactions on Electrical and Electronic Materials
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• v.10 no.2
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• pp.62-65
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• 2009

YBCO-coated conductors, called "second-generation wires," show a remarkably greater increase in the amount or speed of their resistance than BSCCO wires when a quench occurs. This is probably because of the specific resistance at their stabilizer layer, which also affects their voltage grade. YBCO coated conductors with copper as a stabilizer layer have a voltage grade of 1.5-2 V/cm, and those with stainless steel as a stabilizer layer have a voltage grade of about 0.5-0.6 V/cm. The voltage grade of YBCO coated conductors is important in selecting and applying superconducting wires to power instruments later. In this study, two kinds of YBCO-coated conductors with different stabilizer layers and one kind of BSCCO wire were prepared. Among them, based on the YBCO coated conductors that had a stainless steel stabilizer layer with a low voltage grade, five kinds of experimental samples for joining were prepared with the remaining two kinds of wires. Using the prepared samples, the current application properties and the resistance increase in the flux-flow and the quench states of the single wire and the joined wires were compared.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.5
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• pp.862-867
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• 2016

In this study, the embroidery textile conductive wire of conductive yarn was designed into the wearable integrated clothing for sensing the infant's body temperature. To develop a high quality of the stable fiber-based textile conductive wire, firstly the five types of conductive yarns were twisted or covering polyester yarns and the coated conductive fiber with silver(Ag) or iron(Fe). As a result of comparative conductivity in conductive yarns of yarn processing, the 250 denier of conductive yarns with $0.74{\Omega}$/1~5cm were proposed and used for the integrated embroidery textile conductive wire for sensing. During experiments using the proposed embroidery textile conductive wire, measured resistance of thermistor according to the body temperature was correctly delivered to amplifier module, and showed feasible reliability of temperature sensing. As a wearable application, conductive yarns which takes forms of embroidery textile conductive wire would seems to be reliable as a conductive wire and could be replaced by the conductive metal wires.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1988.05a
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• pp.7-9
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• 1988

This paper considers problems which must be overcome to produce long lengths of superconductor wire from the 90K Tc superconducting ceramic material, $Y_1Ba_2Cu_3Ox$. Attention is focused on the powder-in-tube process where the superconducting powder is placed in a tube which is then formed into wire. Two major problems are considered, control of the oxygen level and improvement of Jc in the final wire. The results show that Jc of the wire were $400A/cm^2$ at liquid nitrogen temp.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1999.11a
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• pp.81-84
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• 1999

For the research of the effects on suspension solution with YBCO and BSCCO for elcectrophoretic deposition to prepare superconducting thick-film wire, it was investigated that the preheating technique for the superconducting powders in vacuum system was used with various solvent solutions of acetone, ethanol, toluene and buthanol for electrophoresis. As a result it was useful to remove the influence of remaining and adsorbed solvent solution which was existed between and on the particle surfaces when the specimens of superconducting wire by electrophoresis were treated in vacuum of 10$\^$-3/ Torr and temperature around 200$^{\circ}C$ in bell-jar system. From the prepared superconducting wire samples, the critical current density, Jc was measured by 4-point prove method in liquid N$_2$ at the value of 10$\^$3/ to 10$\^$4/ A/$\textrm{cm}^2$, respectively, for the YBCO and BSCCO superconducting wires.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2003.04a
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• pp.164-170
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• 2003

In this paper, we studied on the firing characteristics and electrical fire analysis of power cord deteriorated by thermal stress. The cross section of PVC insulating cord deteriorated by indirect flame decreased through heat convection. PVC insulating cord deteriorated by direct flame was bumpy shape. The exothermic peak of normal cord was shown at ($526.7^{\circ}C$), but the peaks or on(heat treatment temperature) ($150^{\circ}C$) cord was shown at ($299.6^{\circ}C$) and [$502.2^{\circ}C$]. The exothermic peaks according to high temperature were similar to those of amorphous carbon. In the FT-IR analysis, the absorption peak of normal cord indicated double bond of oxygen and carbon in benzene ring at 1720.0$cm^{1}$. As the HTT was high, the height of characteristic peak decreased and the peak of carbonyl group was shown at about 1625.7$cm^{-1}$. The characteristic peak of single bond(O-H) was shown at about 3479.2$cm^{-1}$. In case of the internal part of wire covering deteriorated by over current, the characteristic peak were shown at about 3417.3$cm^{-1}$ and 1600.2$cm^{-1}$. The above results show that we can distinguish the differences according to the fire pattern through the internalㆍexternal analysis of wire covering deteriorated by heat.

• Progress in Superconductivity
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• v.9 no.1
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• pp.111-114
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• 2007

We have investigated the effect of different heat treatment processes on electrical and magnetic properties of Bi2212/Ag ROSAT wire. The ROSAT wire was fabricated by stacking and arranging 12 filaments Bi2212/Ag tapes in triple rotation symmetry in a Ag tube. ROSAT wires have been prepared using a partial melting method with changing $T_{max}$ and $T_a$ in oxygen atmosphere. The highest critical current density($J_c$) at 65 K under 0 T was $21,158\;A/cm^2$ for wire prepared $890\;^{\circ}C(T_{max})$ and $840\;^{\circ}C(T_a)$, respectively. SEM results indicated that the wire prepared at $890\;^{\circ}C(T_{max})$ and $840\;^{\circ}C(T_a)$ showed better directional phases than the other samples. However the result of magnetic susceptibility measurement indicates that the wire prepared $890\;^{\circ}C(T_{max})$ and $835\;^{\circ}C(T_a)$ had better superconducting phases than the other samples. It was revealed that heat treatment temperature was important factor for superconducting properties of the ROSAT wire.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.48 no.6
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• pp.57-62
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• 2011

This paper proposed a method which is the three types of magnet model for improving field inhomogeneity of superconducting magnet. The length of coil wire was compared for the optimized current pattern using minimum power methods and field inhomogeneity under the specific simulation condition in case of same magnet field strength about each magnet type field inhomogeneity. Length of wire and field inhomogeneity were compared under the same condition(18 target points, 20cm DSV). According to the simulation results, the smaller target points can reduce the wire length but it can not improve the field inhomogeneity. Length of wire and low field inhomogeneity can not improve in same time. However, small DSV and reducing target points can overcome the these problem. And to conclude, if it processes shimming as reducing target points in case of magnet model which is open to space, about the size of same imaging region it needs a lot of current values(or the length of wire) and decreases field homogeneity but it is useful to get small ROI.