• 한국통신학회논문지
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• 제19권7호
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• pp.1296-1303
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• 1994

이 논문에서는 TV 튜너로 사용될 수 있는 MMIC 주파수 변환기를 설계하였다. MMIC를 설계한 때에 수동인덕터는 다른 수동소자나 능동소자에 비해서 그차지하는 면적이 매우 크고 원하지 않는 상호 간섭이 일어나 동작특성이 나빠지고 신뢰성과 재현성도 의심하지 않을 수 없다. 그러나 주파수 변환기에 사용되는 증폭기에 능동인덕터를 적용시키면 높은 안정성과 넓은 대역폭을 유지하게 된다. 믹서나 필터 등에도 능동정합을 이용하면 원하는 부분에서 높은 출력을 얻을 수 있다. 이 연구에서는 능동인덕터를 주파수 변환기에 적용하여 기존의 인덕터를 사용한 것과 비교하였다. 능동인덕터와 능동정합을 이용한 주파수 변환기가 기존의 것보다 면적에서 28.6% 줄이면서도 원하는 주파수 대역에서 더 큰 출력 신호를 얻을 수 있다.

• 한국전기전자재료학회논문지
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• 제16권12S호
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• pp.1286-1291
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• 2003

Quench behavior of resistive superconducting fault current limiters (SFCLS) with various pattern shapes was investigated. The pattern shapes employed were meander, bi-spiral, and spital shapes of identical line width, gap and margin. SFCLS were fabricated from YBCO thin films grown on two-inch diameter Al$_2$O$_3$ substrates under the same conditions. The total length of current limiting paths was the shortest at the spital shape due to its larger useless space. Inductance component of SFCLs with the spiral shape was around two times as high as those of other two shapes. This is not desirable since impedance characteristics of existing power systems can be changed. Resistance rise of current limiting elements was low at a spiral shape before the whole quench completion, which may act as a disadvantage for simultaneous quench in serial connection between current limiting elements, but the temperature tended to have similar values at higher voltages. On the other hand, hi-spital shape was severe at insulation level between current limiting lines. When these aspects were considered, we concluded that a meander shape was appropriate to design for a resistive SFCL based on thin films except the concentration of electric field at edge areas of strip lines.

• Journal of the Optical Society of Korea
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• 제8권4호
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• pp.174-181
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• 2004

Various kinds of systems, that can do target recognition and position detection simultaneously by using infrared sensing detectors, have been developed. In this paper, the detection system TRSS (Thermal target Recognition by Spiral Scanning) adopts linear array shaped uncooled IR detector and uses spiral type fast scanning method for relative position detection of target objects, which radiate an IR region wavelength spectrum. It can detect thermal energy radiating from a 9 m-size target object as far as 200 m distance. And the maximum field of a detector is fully filled with the same size of target object at the minimum approaching distance 50 m. We investigate two types of lens systems. One is a singlet lens and the other is a doublet lens system. Every system includes one aspheric surface and free positioned aperture stop. Many designs of F/1.5 system with ${\pm}5.2^{\circ}$ field at the Efl=20, 30 mm conditions for single element and double elements lens system respectively are compared in their resolution performance [MTF] according to the aspheric surface and stop position changing on their optimization process. Optimum design is established including mechanical boundary conditions and manufacturing considerations.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2001년도 봄 학술발표회 논문집
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• pp.547-552
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• 2001

This research was conducted to investigate the seismic behavior and capacity assessment of circular spiral reinforcement concrete bridge piers used in high strength concrete. The displacement ductility, response modification factor(R), effective stiffness and plastic hinge region etc. was used to assess the seismic behavior and capacity of circular spiral reinforcement concrete bridge piers. The experimental variables of bridge piers test consisted of amount and spacing, different axial load levels. From the quasi-static tests on 9 bridge piers and analysis, it is found that current seismic design code specification of transverse confinement steel requirements and details may be revised.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2001년도 봄 학술발표회 논문집
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• pp.865-870
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• 2001

This paper propose a new seismic detail for ductility enhancement by interlocking spiral reinforcement in the potential yield regions of a wall. Through the theoretical consideration and experiment program, confinement with interlocking spirals lead the structural walls to ductile behavior. All specimens show stable hysteretic behavior and good energy dissipation capacity. Also the increase of shear strength mainly induces a flexural failure mode. As interlocking spiral are used in lapped splice region, they increase the bond strength and prevent a early tensile failure caused by the loss of bond stresses. Consequently, the confinement with interlocking spirals may result in a lower value of force reductions factor, newly proposed detail will be provide more economical design.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 1999년도 추계종합학술대회 논문집
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• pp.283-286
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• 1999

A 2㎓, low noise, low power CMOS voltage-controlled oscillator (VCO) with an integrated LC resonator is presented. The design of VCO relies heavily on the on-chip spiral inductor. An optimized spiral inductor with Q-factor of nearly 8 is achieved and used for the VCO. The simulated result of phase noise is as low as -l14 ㏈c/Hz at an offset frequency of a 600KHz from a 2㎓ carrier frequency. The VCO is tuned with standard available junction capacitors, resulting in an about 400MHz tuning range (20%). Implemented in a five-metal 0.25${\mu}{\textrm}{m}$ standard CMOS process, the VCO consumes only 2㎽ from a single 2.5V supply. It occupies an active area of 620${\mu}{\textrm}{m}$$\times$720${\mu}{\textrm}{m}$.

• 한국정밀공학회지
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• 제12권5호
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• pp.46-56
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• 1995

As demands on the precision bevel gears are increased in the related industry, the exact kinematical investigations of a pair of spherical involute bevel gears are required for the computer aided design. The exact angular velocity ratio based on the characteristics of the spherical involute tooth is derived and verified from the relationship between rotational angles. Elementary kinematics of the gearsets is investigated by applying the transformation of the coordinate systems. The tooth contact lines based on logarithmic tooth-wise curve are examines in three dimentional space. Contact ratio is formulated and simulated according to the system parameters such as shaft angles, pressure angle, and spiral angles. The condition of teeth interference is dervied and the critical numbers of gear teeth are calculated. The whole surface geometry of a spiral bevel gearsets are discretized and visualized by a computer graphic tool.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 하계학술대회 논문집 E
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• pp.2143-2145
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• 1999

Measurements of wind noise, generated by High-voltage overhead transmission lines placed in a uniform flow are carried out in the Anechoic windtunnel. High-voltage overhead transmission lines generates audible wind noise, which cause a serious environment problem. Accordingly, wind noise has become one of major concerns for design engineers and operations personnel. In the present research, tests were mainly performed with various configuration of transmission line with spiral wires. Remarkable noise reduction was observed for some of the spiral transmission lines, compared with the noise generated without the spiral wire.

• 전기학회논문지
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• 제57권12호
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• pp.2269-2275
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• 2008

This paper examined the simulation results after applying not only spiral inductor's 3D EM simulation but also de-embedding technique to reduce the pad's RF effects. When calculating standard deviation with measurement results not only the gain at 0.5GHz${\sim}$4GHz but also noise figure at 1.8GHz${\sim}$4GHz, the simulation results includes de-embedded inductor' model improved gain deviation by 0.171 and noise figure deviation by 0.151 than the results from simulation with foundry inductor equivalent circuit models.

• 한국의류산업학회지
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• 제7권4호
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• pp.419-425
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• 2005

The purpose of this study is to analyze the physical characteristic by directly measuring the wheelchair using disabled women. The subjects were 103 disabled women of wheelchair used women and between 20 - 55 years of age. The result of this study is as follow. There was a remarkable difference in the physical characteristic of wheelchair using disabled women due to their cause of disability. The cause of disability was classified into the 4 groups; poliomyelitis, spiral cord injury, muscular dystrophy, cerebral palsy. Poliomyelitis disability generally had a large horizontal area due to their strong upper body. People with spiral cord injury disability was shown to have the largest height, cervical height, waist back length, crotch length, knee length, The group of muscular dystrophy disabled people have the shortest length of body and also lean. The cebral palsy group of disabled people has an average length and height size body. A comparison of anthropometric measurements of wheelchair using disabled women with National Anthropometric Survey Korea(1997) was significant difference. People with poliomyelitis disability was shown to have a larger waist back length, neck point to breast point compared to normal women, but stature, crotch length was shorter compared to normal women. People with spiral cord injury disability had a similar in the vertical area. The group of muscular dystrophy and cebral palsy disabled people was short and smaller in general compared to a normal woman.