• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1993.04a
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• pp.128-133
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• 1993

본 연구에서는 보강 원통쉘에 대하여 주위 유체의 영향을 고려하여 진동 및 음향방사를 해석하였다. 원통셀의 운동방정식은 Donnell 이론을 적용하였으 며, Contour 적분을 풀지 않고 FFT 알고리즘(Fast Fourier Transform Algorithm)을 이용하여 원통쉘의 진동을 계산하였다. 현재까지의 방사패턴에 관한 연구는 주로 원주 방향에 집중되어 왔으나, 보강 원통쉘의 방사패턴은 원추파 모형에 가까우므로 극좌표 .theta. 방향에 대한 음향방사 패턴에 관한 연구가 이루어져야 한다. 그러므로, 본 연구에서는 극좌표에 관한 방사패턴 에 관하여 주로 고찰하였다.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2014.10a
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• pp.718-722
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• 2014

A method for estimating the cylindrical shape of a sound radiator is presented. It assumes that sound field can be measured by a linear array. A sound field, due to the radiator vibrating with uniform velocity, can be determined by its shape, size, and orientations. Measured data also can be varying from the array's position. To predict the shape of radiators from these measured data, mathematical relation between geometric parameter and measured information is needed. Assume that a radiator is cylinder, the magnitude and phase of measured pressure is related with the length and diameter of radiator, respectively. In this paper, the method for estimating length and shape of a finite cylinder by using its radiated pressure is proposed and verified through experiment.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.40 no.4
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• pp.54-59
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• 2003

In this paper, a cylindrical dielectric antenna with dielectric clad is designed and analyzed. Design parameters of a cylindrical dielectric resonator antenna are calculated from the wave equation of cylindrical dielectric. The variations of characteristics of the antenna are analyzed as varying the thickness and the relative permittivity of its clad. From the results, when the ratio of the outside radius of the dielectric clad to the radius of the cylindrical dielectric is 1.3 and the relative permittivity of the dielectric clad is one-third of the cylindrical dielectric resonator antenna, the relative bandwidth of the antenna is 49%, which is improved by 2.3 times than the cylindrical dielectric resonator antennas. However, the thickness and the relative permittivity of the dielectric clad have not effect on the radiation pattern, beamwidth and gain of the antenna.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.12 no.3
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• pp.425-431
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• 2001

In this paper, on aperture-coupled microstrip cylindrical dielectric resonant antenna(DRA) consisting of dielectric material with permittivity ${\epsilon}_{r}$ = 36 is designed and fabricated fir wireless LAN. First of all, the feedline length, width, slot length and width of the feeding element were calculated using the theory of microstrip transmission line. Radiation element is designed using the theory of cylindrical dielectric cavity, Resonant frequency of the fabricated cylindrical DRA is 2.449 GHz and VSWR, return loss and bandwidth is 1.009, -47 dB and 70 MHz, respectively. Front-to-back radiation ratio is about 12 dB and 3 dB beamwidth of E-plane and H-plane is 110$^{\circ}$ and 90$^{\circ}$ , respectively.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.16 no.5 s.96
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• pp.518-525
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• 2005

In this paper, radiation patterns are simulated and analyzed for inverted-F antenna(IFA) on a cylindrical conducting body like a satellite launcher. First, parametric studies are performed for IFA itself to analyze its characteristics. Then, IFAs on a cylindrical conducting body are simulated and analyzed. Especially, by changing the number of IFAs, the length and the diameter of the cylinder radiation patterns are simulated and analyzed. Finally, IFAs on a cylindrical conducting body are fabricated and their return losses and radiation patterns are measured. Good agreements are observed between the simulated and measured results.

• The Journal of the Acoustical Society of Korea
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• v.13 no.2
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• pp.23-29
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• 1994

In this paper, the measured in-water radiation impedance of cylindrical piezoelectric radiator with finite baffle is compared to the existing theoretical result of that with infinite baffle and the effect of baffle on the radiation impedance is examined. Comparision between measurement and theoretical result of radiation impedance shows that the measured radiation impedance tends to be that of the infinite baffle as the baffle length increases. Another finding of the comparision in that the effect of baffle is more dominant in radiation reactance than in radiation resistance. Therefore, for the use of theoretical radiation impedance of infinite baffle on the design of acoustic transducer, the impedance compensation to the baffle length should conducted.

• Journal of the Korean Society for Nondestructive Testing
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• v.14 no.4
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• pp.228-236
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• 1995

In this paper the method to evaluate shielding deficiency by gamma scanning test was presented and verified theoretically by Monte Carlo code which is one of the best effective method for radiation shielding calculation. The cylindrical shielding model was selected to evaluate shielding deficiency by gamma scanning test. First, the reference shielding according to the design requirement of cask was fabricated specially and reference values were measured with Co-60 source and scintillation detector. As a result with which calculated the reference values, it is shown that maximum deficiency thickness for lead of true cylindrical shielding model was 12mm. To verify this, thickness of lead was calculated by MCNP code and maximum deficiency thickness was 11.6mm. The experimental result obtained by the use of reference shielding was in good agreement with the theoretical result within 4.1%. So, this method can be applied to inspect the shielding ability for great shielding or cask which the radioactive material is used. To perform measurement more exactly, the further work on the development of measuring equipment to display the results on the screen will be required.

• The Journal of the Acoustical Society of Korea
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• v.29 no.1
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• pp.1-9
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• 2010

The mutual radiation impedance was calculated using the spatial convolution in the cylindrical structure. The Cartesian coordinate was transformed into the cylindrical coordinate using the spatial convolution for the cylindrical array structure. This method cannot consider the cylindrical baffle, but can reduce the computation time. The error for not considering the cylindrical baffle was analyzed by the comparison of the spatial convolution method with the quadruple integration method in the cylindrical structure. The mutual radiation resistance in the cylindrical structure was compared with the one in the planar baffle. Based on two kinds of the comparison, we presented the error of the suggesting method in this paper, confirming that the spatial convolution method could be applied to compute the mutual radiation impedance in the cylindrical structure at certain conditions.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.16 no.7 s.98
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• pp.720-731
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• 2005

In this paper, radiation patterns of electrically small inverted-F antennas(IFAs) on an electrically large cylindrical conducting body like a satellite launcher are experimentally studied. First, radiation patterns are obtained by using method of moment and a commercial software tool, HFSS(High Frequency Structure Simulator) and the results are compared and analyzed with experimental ones. Especially, when the size of a cylindrical conducting body is electrically large, the effects of the size of a cylindrical conducting body on radiation patterns are studied by considering only the partial ground in vicinity of antennas. And then, when one and two inverted-F antennas are on the cylindrical conducting body, radiation patterns are simulated and investigated by using method of moment and HFSS. Good agreements are observed among the results by method of moment, HFSS, and experiments.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2009.11a
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• pp.173-174
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• 2009

"방사성폐기물 고화체의 물성시험"에 사용되는 시편을 실험실적으로 제조한 소규모 모의 고화체 시편과 고화공정에서 직접 채취한 소규모 시편, 200L 드럼으로부터 코아시편을 채취 가공하여 만든 시편과 같이 3종류가 있다. 고화공정에서 발생되는 고화체는 일반적으로 200 L 드럼에 주입되며, 고화체의 균일성 정도는 고화공정의 특성, 폐기물/고화매질 혼합비, 200 L 고화체 드럼의 냉각방식에 따라 다르다. 따라서, 실험실에서 제조한 시편과 공정에서 채취한 소규모 시편을 실제 고화공정을 대표할 수 없으며 또한 실제 발생된 고화체의 조성과도 동일하다고 볼 수 없다. 따라서 200 L 실드럼에서부터 코아시편을 채취하여 만든 시편이 고화공정과도 고화체를 대표할 수 있는 시편으로 볼 수 있다. 기 발생고화체(시멘트와 파리핀 고화체 및 잡고체 폐기물)의 영구처분을 위하여 과기부 고시 05-18호 "폐기물 인도기준" 규정과 한국방사성폐기물관리공단의 중 저준위 방사성폐기물 인수기주(안)의 준수 여부를 평가하기 위하여 각 원전의 대표 드럼에 대하여 특성평가시험인 압축강도, 침출, 침수, 열 순환, 내방사성 영향시험을 수행하기위해 실 드럼으로부터 원통형 코아시편을 채취하여 이를 시험검사에 필요한 시험시편으로 가공한 후 표준 특성시험법을 이용하여 물성들을 평가하며 특성평가시험을 위한 시편으로는 L/D=2, L/D=1인 두 종류의 시편을 가공하였으며 압축, 침수, 열순환 및 방사선조사시편은 L/D=2 시편을 제조하였고 침출시험시편은 L/D=1인 시편을 채취하였다.