• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.06a
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• pp.466-467
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• 2007

고주파 전자계에서 플라즈마 가열을 하기 위하여 긴 파장의 펄스를 발생시키는 것이 중요한 데 마이크로파의 발진을 안정시키기 위하여 테이퍼형 지파 도파관을 연계하여 분산관계를 연구하였다.

• Journal of the Korean Institute of Telematics and Electronics D
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• v.36D no.8
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• pp.1-6
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• 1999

The only transmission characteristics in frequency domain is considered when using the tapered transmission line for wide-band impedance matching in MCM and MIC designs. In this paper, the distortion of an electrical pulse with rise/fall time resulting from dispersion and reflection as it propagates along a tapered microstrip line is investigated, and the delay time and distortion rate with respect to input and load impedances are analyzed on triangular and exponential tapered lines. A dispersion model of the phase constant proposed by Kirschning-Jansen is used to meet the frequency, accuracy and microstrip parametric requirements. The triangular tapered line shows both shorter delay time and higher distortion rate than those of the exponential tapered line. Furthermore, the amplitude of signal reflected from load point is calculated in time domain.

• Journal of the Korean Geotechnical Society
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• v.23 no.4
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• pp.59-68
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• 2007

In this study, evaluation of load capacity and CPT-load capacity parameters were performed using calibration chamber tests for different types of piles including straight-side and tapered piles. Various soil conditions were considered in the investigation, aiming at establishing design procedure for foundation of electronic transmission tower structures. Test results show that no significant difference of total load capacity from straight-side and tapered piles, while individual components of base and shaft load capacities were quite different. Based on the test results, values of CPT-load capacity correlation parameters for different pile types were analyzed for the evaluation of both base and shaft load capacities.

• Tunnel and Underground Space
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• v.21 no.3
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• pp.164-173
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• 2011

In the present study, the stability of a compressed air energy storage cavern was numerically assessed by concrete plug shapes in order to investigate the optimal shape of concrete plug. The concrete plugs were cylindrical, embedded cylindrical, tapered, and wedged in shape. The stability assessment was carried out based on factor of safety through a strength reduction method and a volume ratio which refers to the ratio of the volume of yield regions in concrete induced by internal pressure to all concrete volume. The results from the present study indicated that the embedded cylindrical and taper shaped plugs were mechanically more stable than the cylindrical and wedge shaped plugs. However, from a comparison of stress distributions in rock mass between the embedded cylindrical and taper shaped plugs, the taper shaped plug was found to be more optimal than the embedded cylindrical plug, since the embedded cylindrical plug caused more stress concentration in the interface between the plug and rock mass than the taper shaped plug.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.45 no.5
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• pp.40-45
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• 2008

In this paper, a microstrip linear tapered slot antenna is designed. A tapered slot antenna(TSA) has many advantages such as low profile, low weight, easy fabrication, and compatibility with monolithic microwave integrated circuits(MMIC). In addition, it has demonstrated multi octave bandwidth, moderately high gain, and symmetrical E- and H-plane beam patterns. A feed network is implemented with transition between a microstrip and a slot line for the microstrip linear tapered slot antenna. The transition is consist of two sides. One side has a microstrip line, the other side has a slot line. The dimensions of the microstrip and slot line are ${\lambda}_m/4$ and ${\lambda}_s/4$ at the center of the cross section of the microstrip and slot line. In order to get broad bandwidth antenna characteristics, the tapered length is chosen as $4{\lambda}_o$ and termination width is chosen as $1.75{\lambda}_o$. Experimental results show that the microstrip tapered slot antenna has symmetrical E- and H-plane beam patterns with around 5GHz of bandwidth at center frequency of 5.0GHz.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.8 no.6
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• pp.620-628
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• 1997

When the Chebyshev function is applied to design the waveguide transition, it exhibits poor impedance matching characteristics due to impedance discontinuities at the ends of tapered line. In this paper, an improved Chebyshev function, which is obtained by using the convolution property, is proposed to make improvements on the impedance matching characteristics of the waveguide transition. When rectangular to circular waveguide transition is designed by improved function, then the computed return loss is approximately 5 dB better than the conventional Chebyshev function.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.37 no.8
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• pp.45-51
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• 2000

The distortion of an electrical pulse, which has a rise/fall time due to the dispersion and the reflection, on tapered microstrip lines has investigated In time domain. The voltage and current transfer functions are shown for the tapered line. The dispersion distortion obtained by using these trans(or functions are represented for the nonideal square pulse along the triangular, Tchebycheff and exponential tapered lines, and analyzed the influence of the reflection and the frequency dispersion on the distorted voltage wave in the tapered lines. The observed overshoot in front of the distorted wane is caused due to the frequency dispersion and the sustained tail of that comes from the reflection in the tapered line.

• Proceedings of the Acoustical Society of Korea Conference
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• spring
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• pp.379-384
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• 2004

체외 충격파 쇄석술 (ESWL)은 체외에서 발생된 충격파를 체내의 결석이 위치한 부위에 집속하여 결석을 분쇄하는 비 침습적인 치료술이다. 최근 충격파를 이용하여 근관절 질환을 치료하는 체외 충격 파 치료술 (ESWT)이 또한 임상적으로 주목을 받고 있다. 아직 ESWT를 위한 최적의 충격파 노출 조건은 알려져 있지 않지만, 일반적으로 ESWL에 비해 상대적으로 충격파장의 초점 영역이 넓고 낮은 강도의 충격파를 사용한다. 본 연구에서는 ESWT에 적합할 것으로 예상되는 테이퍼 원통형 충격파 발생 방식을 제안하고자 한다. 본 연구에서는 테이퍼 원통형 충격 파 발생 의 초점 부위의 파형을 수치 해석하여 평가하고, 기존 원통형의 경우와 비교하였다. 테이퍼 원통형 충격파 발생기의 시제품을 제작하고, 발생된 강도를 평가하기 위해, 모의 결석을 제작하여 분쇄 효율을 측정하였으며, 결과를 원통형 충격파 발생기와 비교하였다.

• Journal of the Korean Geotechnical Society
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• v.23 no.8
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• pp.35-45
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• 2007

It is known that the response of piles is affected by the shape of pile as well as soil conditions. In order to investigate the characteristics of the axial responses and bearing capacities of non-displacement tapered and cylindrical piles in sands, 12 model pile load tests using a calibration chamber were conducted on model tapered and cylindrical piles, which were specially manufactured to measure the base and shaft load capacities independently. Results of the model tests showed that the shaft load of tapered piles continuously increased with pile settlement, whereas the shaft load of cylindrical piles reached ultimate values at a settlement equal to 4% of pile diameter. Therefore, taper piles have greater shaft loads than cylindrical one at the same settlement. It is also observed that the total load capacity of tapered piles is lower than cylindrical piles for dense sand but is greater than that of cylindrical piles for medium sand. The ultimate unit base resistance of tapered piles was greater than that of cylindrical piles for lateral earth pressure ratio greater than 0.4, and the shaft resistance was greater than that of cylindrical piles irrespective of lateral earth pressure ratio.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.3 no.1
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• pp.81-95
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• 1995

공기의 흐름 중에 있는 유한 날개의 끝에서는 날개끝 와류로 인하여 날개에 내리흐름(downwash)이 발생하게 된다. 이러한 내리흐름은 유도항력을 발생시켜 양항특성이 감소하게 된다. 따라서 날개끝 와류를 적절히 제어하면 어느 정도 유도항력을 감소시킬 수 있다. 본 논문에서는 직사각형 날개와 테이퍼형 날개 끝에 여러 가지 형상의 strake를 장착하거나, 날개끝 와류를 제어하기 위하여 여러 개의 slot을 형성시켰을 때의 양항특성을 실험 및 수치해석으로 연구한 결과를 기술하였다. 실험결과 직사각형 날개끝에 장착한 wing tip strake의 밑변을 바깥쪽으로 절단한 wing tip strake의 양항특성이 받음각 $8^{\circ}$ 이상에서 우수하였고, 반면에 밑변을 절단하지 않은 경우는 받음각 $0^{\circ}\;^{\sim}\;8^{\circ}$ 사이에서 기본날개보다 양항비가 증가하였다. 테이퍼형 날개끝에 wing tip strake를 장착하였을 때의 양항비는 받음각 전 범위에 걸쳐 기본날개보다 증가하였으며, 받음각$8^{\circ}$ 이상에서 wing tip strake의 밑변을 절단하지 않은 wing tip strake의 양항특성이 우수하였다. 방사형 다중슬롯의 경우 날개끝의 앞전보다 뒷전 쪽에 형성시키는 것이 양항비특성이 우수하였다.