• Proceedings of the Korean Institute of Building Construction Conference
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• 2012.11a
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• pp.171-172
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• 2012

In this study the continuous rectangular spiral hoop is used for saving cost and time, solving manpower shortage, and the quality of structures. Generally the use of continuous spiral reinforcement in reinforced concrete elements improve the strength and the ductility of the concrete. Savings in cost and time is demonstrated with the continuous rectangular spiral hoop through the mock up test of beam and column elements. In case of a 4m column element the time of rebar work decreases up to 40% compared with traditional hoop, and in case of a 8m beam the time also decreases 40%. This study present the construction method and details.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.13 no.5
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• pp.468-474
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• 2002

In this paper a novel two-arm microstrip spiral antenna with a circular slot on the ground plane is presented. The proposed antenna structure is constructed in a planar form without a balun circuit and the radiation characteristics of conventional and eccentric spiral antennas are obtained simultaneously. The main beam direction is normal to the plane of the spiral for characteristic frequency band and the direction of the main beam moves linearly into $\theta$ and $\phi$ direction as the frequency increases.

• Journal of the Korean Solar Energy Society
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• v.24 no.1
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• pp.47-52
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• 2004

An experimental investigation was performed to compare ice making characteristics of ice storage system with smooth and spiral tube. During the freezing processes in the shell and tube type ice storage tank with smooth tube, heat resistance of the ice layer caused a decrease in freezing rate. Also, the phenomena of bridging made the increasing rate of ice making less. In order to improve the ice making rate, spiral tube(pitch=6mm) was used in the present study. The ice making rate and the decreasing of bridging for the spiral tube were higher than those for the smooth tube.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.18 no.3
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• pp.216-218
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• 2005

Planar spiral inductors on silicon substrates were optimally designed using MATLAB, which is a tool to perform numerical computations with matrices. The equivalent circuit parameters of the spiral inductors were extracted from the data measured from the spiral inductors fabricated using a 0.18 $\mu\textrm{m}$ RF CMOS process. The metal width, which is a critical design parameter, was optimized for the maximum quality factor with respect to the operating frequency.

• Proceedings of the IEEK Conference
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• 2003.07b
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• pp.987-990
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• 2003

This paper presents a cross-coupled RF VCO with high-Q MEMS-based spiral inductors. Since the use of high-Q inductors is critical to VCO design, MEMS-based spiral inductors with the Q-factor of nearly 22 are used for the RF VCO with an active cascode current source. The RF VCO circuits including spiral inductors have been designed and simulated in GaAs MMIC-MEMS process. The simulation results of the VCO circuits showed the phase noise of -180dBc/Hz at an offset frequency of 500KHz. The RF VCO circuit simulatinon used 2mA DC current and 3.3V supply.

• ETRI Journal
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• v.31 no.1
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• pp.71-73
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• 2009

In this letter, novel antennas with two spiral elements are presented for ultra-wideband application. The original antenna consists of a T-shaped microstrip feed line, two spiral radiating elements, and a ground plane with two circular slots. It measures 30 mm ${\times}$ 40 mm ${\times}$ 1.6 mm. Spiral elements are used to increase the lower bandwidth limit. To further reduce the size of the antenna, the original antenna is cut in half by using the symmetry of the surface current distributions. The proposed antennas feature omnidirectional radiation patterns and good gain flatness.

• Journal of The Korean Astronomical Society
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• v.29 no.spc1
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• pp.79-80
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• 1996

We performed CCD surface photometry in B,V,R and I filters for three southern spiral galaxies:ESO598-G009,NGC1515 and NGC7456. Isophotal map, luminosity profile, ellipticity profile and position angle profile were obtained for these galaxies using SPIRAL package. The results show that one of the galaxies, ESO598-G009 has relatively large bulge component and changes in position angle due to spiral arms. The NGC7456 has very small bulges; and the isophotal map of the NGC1515 shows that it is a typical spiral galaxy with bar.

• 한국가시화정보학회:학술대회논문집
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• 2007.11a
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• pp.143-148
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• 2007

In comparison with previous researches for swirling flow, the spiral flow self-generated in the spiral flow nozzle has some different characteristics. It is not needed a compulsive tangential momentum to get its velocity component and has long potential core, relatively low swirl ratio, and high focusing ability. In this study, the self-generated mechanism of the spiral flow was clarified and the effect on the width of annular slit on spiral flow characteristics was investigated experimentally and numerically. As a result, the existence of tangential velocity component regardless of a compulsive angular momentum is clarified and the results obtained by experiment have a satisfactory agreement with those by numerical method, quantitatively and qualitatively.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.11a
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• pp.379.1-379
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• 2002

In this paper the leakage prediction and rotordynamic analysis of an annular seal with a smooth rotor and spiral-grooved stator are performed. For developing a theoretical model, the three-control-volume analysis of the circumferentially-grooved seal is expanded by considering pressure reduction due to the pumping effect of spiral groove and pressure flow through the spiral groove. Validation to the present analysis is achieved by comparisons with available experimental data. (omitted)

• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2003.11a
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• pp.260-264
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• 2003

It is possible to design the high performance, integration and low cost radio frequency components by using LTCC(Low Temperature Cofired Ceramic) technology. But there is a critical point to design the spiral inductor because of crosstalk effects. of the crosstalk effect of the spiral inductor are investigated using full-wave analysis of the FEM(Finite Element Method) in this paper. The results show that input power of the spiral inductor are coupled from 0.1% to 10% above 3GHz. Therefore, we should consider the crosstalk effects when we design the LTCC.