• Ocean Systems Engineering
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• 제4권4호
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• pp.327-342
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• 2014

The tension leg platform (TLP) is one of the compliant structures which are generally used for deep water oil exploration. With respect to the horizontal degrees of freedom, it behaves like a floating structure moored by vertical tethers which are pretension due to the excess buoyancy of the platform, whereas with respect to the vertical degrees of freedom, it is stiff and resembles a fixed structure and is not allowed to float freely. In the current study, a numerical study for square TLP using modified Morison equation was carried out in the time domain with water particle kinematics using Airy's linear wave theory to investigate the effect of changing the tether tension force on the stiffness matrix of TLP's, the dynamic behavior of TLP's; and on the fatigue stresses in the cables. The effect was investigated for different parameters of the hydrodynamic forces such as wave periods, and wave heights. The numerical study takes into consideration the effect of coupling between various degrees of freedom. The stiffness of the TLP was derived from a combination of hydrostatic restoring forces and restoring forces due to cables. Nonlinear equation was solved using Newmark's beta integration method. Only uni-directional waves in the surge direction was considered in the analysis. It was found that for short wave periods (i.e., 10 sec.), the surge response consisted of small amplitude oscillations about a displaced position that is significantly dependent on tether tension force, wave height; whereas for longer wave periods, the surge response showed high amplitude oscillations that is significantly dependent on wave height, and that special attention should be given to tethers fatigue because of their high tensile static and dynamic stress.

• 한국의학물리학회지:의학물리
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• 제9권1호
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• pp.37-46
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• 1998

Beta-particle energy distributions of the radionuclides in medicine are calculated for the medical physics applications. The radial component solutions of Dirac wave equations are evaluated for a point-nucleus un screened Coulomb potential. The WKB method is employed to correct the screening due to the orbital-electron cloud. Fierz interference terms are ignored. The radionuclides considered are $\^$32/P, $\^$90/Y, $\^$131/I, $\^$166/Ho, $\^$192/Ir, $\^$198/Au, $\^$153/Sm, $\^$169/Er and $\^$188/Re. A total of 9 beta-spectra for the radionuclides, currently in domestic use or potential use in the near future, are calculated with enough accuracy and presented in graphs and tables.

• 비파괴검사학회지
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• 제36권2호
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• pp.112-120
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• 2016

The nonlinearity parameter is frequently measured as a sensitive indicator in damaged material characterization or tissue harmonic imaging. Several previous studies have employed the plane wave solution, and ignored the effects of beam diffraction when measuring the non-linearity parameter ${\beta}$. This paper presents a multi-Gaussian beam approach to explicitly derive diffraction corrections for fundamental and second harmonics under quasilinear and paraxial approximation. Their effects on the nonlinearity parameter estimation demonstrate complicated dependence of ${\beta}$ on the transmitter-receiver geometries, frequency, and propagation distance. The diffraction effects on the non-linearity parameter estimation are important even in the nearfield region. Experiments are performed to show that improved ${\beta}$ values can be obtained by considering the diffraction effects.

• Bulletin of the Korean Chemical Society
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• 제30권1호
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• pp.145-148
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• 2009

Nucleotides are the building blocks of nucleic acids and essential for many cellular functions. In this study, ultrasonic absorption spectra of $\beta$-cyclodextrin ($\beta$-CD) and adenosine 5'-monophosphate (AMP) in aqueous solution were measured over the broad frequency range 0.1-40 MHz with emphasis on the low-frequency range below 1 MHz. Here we show that the interaction of $\beta$-CD and AMP complies with a typical spectrum of a single relaxation process. We determined reliable rate (kb) and equilibrium (K) constants and a standard volume change ($\Delta$V) of the reaction. They are $k_b=2.3{\times}{{10^{-6}}_s}^{-1},\;K=89M^{-1},\;and\;{\Delta}V=13.8(10^{-6}m^3mol^{-1})$, respectively.

• 한국전자통신학회논문지
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• 제9권11호
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• pp.1277-1282
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• 2014

본 논문에서는 청소년의 집중과 관련된 EEG신호를 분석하는 것을 목적으로 하여 글자 시각자극 과제로 제시했을 때 유발되는 EEG신호를 분석한 결과를 제시한다. 시각자극 과제는 글 속에서 틀린 조사들을 찾는 것이다. 본 실험에서는 선행연구결과에 따라 EEG신호 중에서도 특히 SMR파와 중간 베타파를 분석하는데 초점을 맞추었다. 실험결과로서 피험자의 집중력과 상관성이 높은 채널의 위치와 중간 베타파 대역을 제시하였다.

• Archives of Pharmacal Research
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• 제25권6호
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• pp.903-909
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• 2002

Research in the cytokine field has grown exponentially in recent years, and the validity of such studies relies heavily on the appropriate measurement of levels of cytokines in various biological samples. Transforming growth factor (TGF)-$\beta$, a hormonally active polypeptide found in normal and transformed tissue, is a potent regulator of cell growth and differentiation. The most widely used bioassay for TGF-$\beta$ is the inhibition of the proliferation of mink lung epithelial cells. Though detection of [$^3$H]thymidine incorporation is more sensitive than the MTT assay, it presents some disadvantages due to the safety and disposal problems associated with radioisotopes. In this study, we attempted to ascertain the experimental conditions which could be used for measuring the in vitro biological activity of TGF-$\beta$ in a safer and more sensitive way compared with the currently available methods. We compared the commonly used method, the MTT assay, to the XTT assay using different parameters including cell number, incubation time and the wave length used for detecting the product. We examined the anti-proliferative activities of TGF-$\beta$ in three different cell lines: Mv-1-Lu mink lung epithelial cells, MCF10A human breast epithelial cells and H-ras-transformed MCF10A cells. Herein, we present an experimental protocol which provides the most sensitive method of quantifying the biological activity of TGF-$\beta$, with a detection limit of as low as 10 pg/ml: Mv-1-Lu or H-ras MCF10A cells ($1{\times}10^5/well$) were incubated with TGF-$\beta$ at $37^{\circ}C$ in a humidified $CO_2$ incubator for 24 hr followed by XTT treatment and determination of absorbance at 450 or 490 nm. Our results may contribute to the establishment of an in vitro bioassay system, which could be used for the satisfactory quantitation of TGF-$\beta$.

• 한국전자파학회논문지
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• 제7권4호
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• pp.353-362
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• 1996

본 논문에서는 토끼를 대상으로 하여 그 두부에 전자파가 조사(照射)된 경우에 대해 토끼 두부를 3충 구모델로 근사해서 SAR분포를 계산하였다. 계산 결과를 확인하기 위해 주파수 2,450MHz인 마이크로파를 출력세기별로 5그룹으로 설정하여 각각에 대한 노출 전 후의 EEG를 전두부(前頭部)에서 측정하였다. 실험에서 전자파 조사 후에는 뇌전위의 전체평균값은 조금 감소히였고, 특히 $\theta$, $\delta$그리고 $\beta$파의 평균합성비율은 증가하였다. 이 결과는 마이크로파 조사후 전기적 생리활동의 감소와 뇌파의 속파화 경향을 나타낸다. 측정된 뇌전위로써 생체에 대한 전기 생리적 효과를 정량적으로 파악하여 최대허용노출(Maximum Permissible Exm posure)의 객관적인 추정을 하였다.

• 한국의류학회지
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• 제29권9_10호
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• pp.1230-1240
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• 2005

The purpose of this study was to apply a scientific and systematic method for assessing fashion goods' TV ads effects by EEG and questionnaires as determined by the type of ads appeal. Ads stimulants used in the survey were limited to underwear and sportswear that were advertised during $2000{\sim}2002$ on TV: 4 information-transferring and 4 emotion-evoking ads were used. Subjects were thirty healthy male and female college students. EEG was extracted from six lobes and the recorded EEG was analyzed by the range of frequency of ${\theta},\;{\alpha}\;and\;{\beta}$ waves. Data were analyzed by SPSS 11.0 with reliability test, $x^2$-analysis, t-test and frequency analysis. The emotion-evoking ads showed higher scores in memory, recall and attitude towards the ads. The responses of ${\theta}\;and\;{\alpha}$ wave were active throughout the ads but the response of ${\beta}$ wave was not. The results by the survey and the EEG test showed high similarities, indicating the EEG tests could be used as the supplementary tool for measuring ads effects.

• 한국전자통신학회논문지
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• 제11권7호
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• pp.717-722
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• 2016

본 논문은 집중력에 대한 문제를 해결할 수 있는 과정으로서 뇌파의 변화를 관측하는 것을 목적으로 하고 있다. 본 연구에서의 실험에서는 뇌파 실험의 피험자들에게 두 가지 과제를 수행하도록 하였는데, 첫 번째 과제는 스마트폰으로 일정시간동안 게임을 하도록 한 후 단어를 암기하는 것이고, 두 번째 과제는 종이책을 읽은 후 단어를 암기하는 것이다. 본 논문에서는 피험자의 과제 수행 중에 발생하는 뇌파를 집중력과 관련된 성분인 SMR파와 중간 베타파로 나누어 분석한 결과를 제시한다.

• 대한화학회지
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• 제14권3호
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• pp.213-219
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• 1970

In the presence of hydrogen peroxide, the effects of temperature and pH to the catalytic reaction velocity of cupric -thiocyanate and the quantities of reduction products adsorbed on the D.M.E. have been studied by polarographic method. According to these experiments, the following empirical equation has been derived for the relation among temperature $T_i$, concentration of hydrogen ion $pH_i$ and adsorbed cuprous-thiocyanate in moles/$cm^2Z_{ij}$, and rate constant log$K_{ij}$ $$log\;K_{ij}=\frac{1}{T_i}\{A(pH_j)+B\}+C(pH_j)+D$$ $$Z_{ij}=\frac{1}{T_i}\{{\alpha}(pH_j)^{\frac{1}{2}}+{\beta}\}+{\gamma}(pH_j)^{\frac{1}{2}}+{\delta}$$ where, A,B,C,D and {$\alpha},{\beta},{\gamma},{\delta}$ are constants. The Calculated values by both equations are well agreed with empirical values within 8% in the error.