• Journal of the Earthquake Engineering Society of Korea
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• v.9 no.3 s.43
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• pp.51-58
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• 2005

Many RC building structures of multiple uses constructed in Korea have the Irregularities of torsion and soft story at bottom stories simultaneously. Seismic design codes generally require dynamic analysis and to take into account the effect or earthquake excitations in the orthogonal direction using the approximate methods of 100/30 and SRSS for type of building structures. And ail buildings should be designed to be safe in any direction of earthquake input. But, most of designers have difficulty in considering the orthogonal and directional effect of earthquake. The objective of the study stated herein is to verily 1) the effect of the choice of the reference axes on the seismic design member forces by comparing the analytical results on member forces using the principal axes suggested by Wilson and the global axes generally adopted in design office, 2) the validity or the 100/30 and SRSS methods by comparing the member forces obtained through linear elastic time history analysis with those obtained through using response spectrum analysis and 100/30 (or SRSS) methods. Based on the observations on the analytical results, it is concluded as follows; 1) The values of member forces by principal axes can be about $15\%$ smaller than those by the global axes in the example structure. 2) Though the values of member forces given by time history analysis are generally within the peak values predicted by 100/30 and SRSS methods, many member force vectors $(P,\;M_y,\;and\;M_z)$ by lime history analysis were located outside the boundaries predicted by the approximate method such as the 100/30 method.

• Journal of the Korean Society of Food Science and Nutrition
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• v.37 no.10
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• pp.1363-1368
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• 2008

The extraction and quantitative analysis conditions for astaxanthin from Haematococcus pluvialis, and the structural characteristics of H. pluvialis extract, H. pluvialis hydrolysate and synthetic astaxanthin were investigated using UV/visible and FT-IR spectrometers. Astaxanthin was dissolved in methanol, and then treated to enhance the solubility by sonication for 45 min. With sonication pretreatment, the solubility of astaxanthin increased up to 1.5 times compared to that without sonication. The extracts were hydrolyzed by cholesterol esterase for the analysis of H. pluvialis extract containing astaxanthin ester. A HPLC method using reverse phase C18 column with methanol-water (95:5, v/v) as mobile phase was developed to analyze astaxanthin. After hydrolysis, the absorption spectrum of H. pluvialis hydrolysat was changed to similar pattern to synthetic astaxanthin, confirming the extraction and analysis condition of astaxanthin from H. pluvialis.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.41 no.5
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• pp.435-442
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• 2017

A catadioptric optical system produces images by refraction and reflection. To improve the image quality, the shape of the secondary mirror supporters should be determined to ensure that the centering error and tilt of secondary mirror are very small, and the main mirror receives the maximum amount of light. Furthermore, random acceleration vibration has a severe effect on the optical system for observation reconnaissance. In order to obtain the best design under these circumstances, the volume of the secondary mirror supporter must be minimized while satisfying the constraints expressed in standard deviations of the centering error and tilt. It is difficult to analytically calculate the design sensitivities of the standard deviations, because they are statistically defined. Hence, after their second-order regression equations were determined using a response surface methodology, an optimal geometric design was obtained. As a result, it was found that the method proposed in this paper, which included a random vibration analysis, was effective in obtaining the optimal design for a secondary mirror supporter with robustness.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1995.10a
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• pp.289-295
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• 1995

구조물의 동적부하에 대한 동적변형 응답을 정확히 예측하고, Over Design이나 Under Design이 아닌 합리적인 설계방안의 개발은 중요한 과제이다. 동적강도해석이나 소음 승차감과 같은 진동 및 충격에 기인하는 제반 문제를 복잡한 구조물을 대상으로 합리적으로 처리하기 위한 Dynamic Design Analysis는 높은 신뢰성의 추구와 더불어 필요불가결한 기술이 되고 있다. 동적해석 방법으로는 현재 유한요소법이 널리 사용되고 있으며 여러 종류의 범용 프로그램들이 보급되어 있는 실정이다. 그러나 특히 동적문제에 있어서는 형상이나 거동이 복잡한 구조물의 경우, 또는 차량의 차체와 같이 많은 장착물이 부착된 경우에는 유한요소법의 적용이 곤란하여, 지금까지 대처할 수 있는 유용한 방법이 없었다. 따라서 비교적 용이하고 간단하게 적용가능한 진동실험을 기초로 한 구조물의 동적 응답해석 및 설계 방안의 개발이 필요하다. 본 연구에서는 진동시험으로 얻어진 부분구조물의 응답특성과 결합특성으로부터 결합 후의 응답특성을 예측할 수 있는 방법을 전달함수합성이론을 기초로하여 프로그래밍 package화 한다. 그리고 평판구조물에 대하여 진동시험과 컴퓨터 시뮬레이션을 통하여 개발된 방법의 타당성을 검증한다. 또한 실제 차량에서 차체만의 진동시험과 엔진의 자유진동시험에 의한 시험데이터로부터 차체와 엔진이 마운트 결합된 후의 진동특성을 예측한다. 진동시험시에 입력과 출력에 노이즈가 필연적으로 혼입되어 주파수응답함수의 크기(magnitude)와 위상(phase)을 왜곡시킨다. 특히 위상의 왜곡은 복소수연산을 하는 전달함수합성법의 결과에 중요한 영향을 미치게 된다. 본 연구에서는 데이타 획득시 입력과 출력의 시간지연으로 생기는 위상왜곡을 보정하는 방법을 제시하고, 그 개선 정도를 조사한다.는 소견의 확실도로서 가능성을 표현한 것이다. 예를 들면, 진동진폭 스펙트럼상에 2X 성분이 상당히 크게 나타나 정렬불량의 가능성이 0.7 정도라고 판정하는 것 등은 이러한 수치적진리치를 이용하는 방법이다. 그러나 상기의 수치적 표현만으로는 확실도를 한개의 수치로서 대표하게 하는 것은 진단의 정밀도에 문제가 있을 것으로 생각된다. 따라서 언어적진리치가 도입되어 [상당히 확실], [확실], [약간 확실] 등의 언어적인 표현을 이용하여 애매성을 표현하게 되었다. 본 논문에서는 간이진단 결과로부터 추출된 애매한 진단결과중에서 가장 가능성이 높은 이상원인을 복수로 선정하고, 여러 종류의 수치화할 수 없는 언어적(linguistic)인 정보ㄷㄹ을 if-then 형식의 퍼지추론으로 종합하는 회전기계의 이상진단을 위한 정밀진단 알고리즘을 제안하고 그 유용성을 검토한다. 존재하여도 모우드 변수들을 항상 정확하게 구할 수 있으며, 또한 알고리즘의 안정성이 보장된 것이다.. 여기서는 실험실 수준의 평 판모델을 제작하고 실제 현장에서 이루어질 수 있는 진동제어 구조물에 대 한 동적실험 및 FRS를 수행하는 과정과 동일하게 따름으로써 실제 발생할 수 있는 오차나 error를 실험실내의 차원에서 파악하여 진동원을 있는 구조 물에 대한 진동제어기술을 보유하고자 한다. 이용한 해마의 부피측정은 해마경화증 환자의 진단에 있어 육안적인 MR 진단이 어려운 제한된 경우에만 실제적 도움을 줄 수 있는 보조적인 방법으로 생각된다.ofile whereas relaxivity at high field is not affected by τS. On the other hand, the change in τV does not affect low field profile but strongly in fluences on bot

• Journal of the Korean Society for Nondestructive Testing
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• v.35 no.2
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• pp.141-149
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• 2015

In the fabrication of electronic circuits used in electronic products, molybdenum thin films are deposited on semiconductors to prevent oxidation. During the deposition, the presence of a particle or dust at the interface between the thin film and substrate causes the decrease of adhesion, performance, and life cycle. In this study, a damage measurement targeting two kinds of glass substrate, with and without particles, was performed in order to measure the change in the molybdenum thin film deposition area in the presence of a particle. Clean and dirty molybdenum thin film specimens were fabricated and directly deposited on a substrate using the sputtering method, and a reflection-type digital holographic interferometer was configured for measuring the damage. Reflection-type digital holography has several advantages; e.g., the configuration of the interferometer is simple, the measurement range can be varied depending on the magnification of a microscopic lens, and the measuring time is short. The results confirm that reflection-type digital holography is useful for the measurement of the damage and defects of thin films.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.31 no.3
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• pp.23-30
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• 2003

In this study, the various load cases by specified by the IEC61400-1 international specification and GL Regulations for the wind energy conversion system were considered, and a specific composite structure configuration which can effectively endure various loads was proposed. In order to evaluate the structure, the structural analysis for the composite wind turbine blade was performed using the finite element method(FEM). In the structural design, the acceptable configuration of blade structure was determined through the parametric studies, and the most dominant design parameters were confirmed. In the stress analysis using the FEM, it was confirmed that the blade structure was safe and stable for all the considerd load cases. Moreover the safety of the blade root joint with insert bolts, newly devised in this study, was checked against the design loads and also the fatigue loads. The fatigue life for operating more than 20 years was estimated by using the well-known S-N linear damage rule, the load spectrum and Spera's empirical equations. The full-scale static test was performed under the simulated aerodynamic loads. from the experimental results, it was found that the designed blade had the structural integrity. Furthermore the measured results were agreed with the analytical results such as deflections, strains, the mass and the radial center of gravity. The studied blade was successfully certified by an international institute, GL, of Germany.

• Journal of Radiation Protection and Research
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• v.38 no.1
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• pp.37-43
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• 2013

In case of neutron dose measurement using TLDs (thermo-luminescence dosimeters), because the neutron energy dependence of the TLD is very high, the calibration of the energy response according to the characteristics of the neutron spectrum of workplace is required. In the present study, the ambient dose equivalent rates inside and around the Long-Counter (neutron detector) with narrow and complex inside in the neutron field of $^{252}Cf$ were evaluated. The calibration factors to account for the neutron energy dependence of TLDs were established for both the bare and $D_2O$ modulated $^{252}Cf$ neutron beams, respectively. The values of the TLD's measurement were compared with the computational results of the MCNPX (Monte Carlo N-Particles transport code). When using the two calibration factors of the TLD than a single calibration factor, the measured and the calculated values at the point of verification outside and inside the Long-Counter were in more good agreement. This results show that TLD should be calibrated in the reference neutron field similar to workplace situation.

• The Journal of Engineering Research
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• v.2 no.1
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• pp.113-123
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• 1997

The purpose of this paper is an optimum design of the shaped Cassegrainian antenna system for the base station. The process of the shaped Cassegrainian antenna design is as follows : 1) the aperture field distribution is determined so as to meet design specifications, 2) a proper design parameter is selected, 3) extracting of the dimension data for the main and sub-reflector antenna To do these, Hansen's distribution is chosen as the aperture field, and the far-field pattern from the aperture is predicted by the angular spectrum. Firstly, the aperture field distribution is designed to satisfy the specification for design frequency, it is confirmed if this distribution meet the specification for another frequency band. The main- and the sub-reflectors are synthesized so as for the given beamwaveguide feed pattern to be transformed into the prescribed aperture distribution. The designed system has circular aperture, left-right symmetry and no tilted structure. The continuous surface functions of reflectors are obtained by adopting the global interpolation technique to the discrete reflector profiles. Jacobi polynomial-sinusoidal is used as the basis function. A Ka-band Cassegrainian antenna operates over 17.7 – 20.2 GHz for down-link band and 27.5 – 30 GHz for up-link band is designed.

• The Journal of the Petrological Society of Korea
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• v.22 no.1
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• pp.71-81
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• 2013

Measuring the distance between benchmarks placed on a volcano tens to thousands of meters apart can sometimes pinpoint where and when magma is rising toward the surface. Rising magma will sometimes push overlying rocks upward or shove them aside. In either case, one part of the volcano may actually move horizontally relative to another part from as little as a few millimeters to as much as several tens of meters. The challenge in measuring such changes with an electronic distance meter is putting benchmarks in the right places and making frequent measurements between pairs of benchmarks. An electronic distance meter is an instrument that both sends and receives an electromagnetic signal. Depending on the distance between the EDM and reflector, the wavelength of the returned signal will be out of phase with the transmitted signal. The instrument compares the phase of the transmitted and received signals and measures the phase difference electronically. There is a wide range of EDM capabilities in range and precision, but for volcano monitoring purposes, short-range (less than 10 km) to medium-range (less than 50 km) EDM's are typically used. Short-range EDM's transmit and receive the near visible infrared part of the electromagnetic spectrum for measuring distances with an accuracy of about 5 mm.

• Journal of Radiation Protection and Research
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• v.39 no.2
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• pp.81-88
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• 2014

Recently, a new imaging method, gamma vertex imaging (GVI), was proposed for the verification of in-vivo proton dose distribution. In GVI, the vertices of prompt gammas generated by proton induced nuclear interaction were determined by tracking the Compton-recoiled electrons. The GVI system is composed of a beryllium electron converter for converting gamma to electron, two double-sided silicon strip detectors (DSSDs) for the electron tracking, and a scintillation detector for the energy determination of the electron. In the present study, the modules of a charge sensitive preamplifier (CSP) and a shaping amplifier for the analog signal processing of DSSD were developed and the performances were evaluated by comparing the energy resolutions with those of the commercial products. Based on the results, it was confirmed that the energy resolution of the developed CSP module was a little lower than that of the CR-113 (Cremat, Inc., MA), and the resolution of the shaping amplifier was similar to that of the CR-200 (Cremat, Inc., MA). The value of $V_{rms}$ representing the magnitude of noise of the developed system was estimated as 6.48 keV and it was confirmed that the trajectory of the electron can be measured by the developed system considering the minimum energy deposition ( > ~51 keV) of Compton-recoiled electron in 145-${\mu}m$-thick DSSD.