• Bulletin of the Korean Chemical Society
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• 제27권8호
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• pp.1186-1188
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• 2006

In this paper a new theory is presented to treat the problem of stimulated absorption and emission of photons between energy levels from the standpoint of discrete quantum jumps. In order to implement the theory a scheme to avoid the quantum Zeno effect is proposed. Numerical simulations are performed to demonstrate that this approach does not contradict the principles of the standard wave mechanics. It is shown that with this approach one can obtain photon observation statistics as well.

• Journal of Ginseng Research
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• 제8권2호
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• pp.75-81
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• 1984

The effect of the saponin fraction extracted from Panax ginseng C.A. Meyer on the absorption of ${\alpha}$-tocopherol in rat has been investigated and realized that the saponin fraction stimulated not only the absorption of ${\alpha}$-tocopherol (1.5-2 times that of control) but also its transport and excretion. ${\alpha}$-tocopherol is known to be transported mainly in the form of ${\beta}$-lipoprotein but the present study showed that the ${\alpha}$-tocopherol was transported in the form of albumin bound or micellar structure as well.

• Journal of Nutrition and Health
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• 제15권1호
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• pp.1-8
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• 1982

유당(乳糖)을 함유(含有)하지 않은 분유식(粉乳食)을 섭취한 흰쥐의 장관내(腸管內)에는 Casein함유식(含有食)을 섭취한 때와 마찬가지로 C.P.P.가 생성(生成)되며 이 C.P.P.에 의해 장관내(腸管內) 칼슘이 증가(增加)되며 소장하부(小腸下部)에서의 칼슘흡수(吸收)가 촉진(促進)되는 것을 밝혔다. 그러나 10% 또는 30% Lactose를 첨가한 경우, 위의 제(諸) 현상(現象)은 보이지 않았다. 이것은 장관내(腸管內)에서의 칼슘의 가용화(可溶化) 및 흡수(吸收)에 대 한 C.P.P의 촉진효과(促進效果)가 유당(乳糖)과는 독립적(獨立的)으로 일어나는 것임을 시사함이다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2014년도 제46회 동계 정기학술대회 초록집
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• pp.179.1-179.1
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• 2014

Si nanowires have exhibited unique optical characteristics, including nano-antenna effects due to the guided mode resonance, significant optical absorption enhancement in wide wavelength and incident angle range due to resonant optical modes, graded refractive index, and scattering. Since Si poor optical absorption coefficient due to indirect bandgap, all such properties have stimulated proposal of new optoelectronic devices whose performance can surpass that of conventional planar devices. We have carried out finite-difference time-domain simulation studies to design optimal Si nanowire array for solar cell applications. Optical reflectance, transmission, and absorption can be calculated for nanowire arrays with various diameter, length, and period. From the absorption, maximum achievable photocurrent can be estimated. In real devices, serious recombination loss occurring at the surface states is known to limit the photovoltaic performance of the nanowire-based solar cells. In order to address such issue, we will discuss how the geometric parameters of the array can influence the spatial distribution of the optical field (resulting optical generation rate) in the nanowires.

• 한국농림기상학회지
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• 제5권1호
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• pp.36-42
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• 2003

쓰레기 매립지 침출수의 중금속과 유해성분을 자작나무와 이태리 포플러 묘목이 얼마나 흡수, 제거하는지를 알아보기 위해서 침출수 원액, 50% 침출수, 25% 침출수 그리고 대조구 등 4개의 처리로 나누어서 관수하였다. 실험이 끝난 후에 뿌리, 줄기, 잎을 분쇄기로 분쇄하고 그 함량을 Inductively Coupled Plasma emission spectrometer(ICP)로 조사하였다. 위에서 살펴 본 것과 같이 이태리 포플러와 자작나무 모두 쓰레기 매립지 침출수의 유해 중금속을 흡수 할 수 있는 능력이 있어 매립지나 황폐지 같은 지역의 빠른 조림을 위해서 활용이 기대되는 수종임을 알 수 있다. 특히 토양의 비소(As), 수은(Hg), 코발트(Co)그리고 니켈(Ni)등의 오염이 문제가 되는 지역에 이들 수종을 식재하게 되면 뿌리를 통해서 이들 원소를 흡착, 흡수할 수 있는 효과를 올릴 수 있다.

• 고려인삼학회:학술대회논문집
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• 고려인삼학회 1984년도 학술대회지
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• pp.113-118
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• 1984

한국산 인삼(Panax ginseng C. A. Meyer) 뿌리에서 추출한 사포닌 성분이 ${\alpha}$-tocopherol의 항산화 활성에 미치는 영향을 실험관 내 실험과 동물실험으로 관찰하였다. 흰쥐(Sprague-Dawley, male, $18{\~}200g$)의 마이크로좀 분획을 NADPH, $Fe^{+3}$, ATP $\alpha^{-+}$-ocopherol 과 인삼 사포닌 분획 (대조군은 사포닌 분획대신 같은 부피의 물)을 함유한 혼합물에서 30분간 반응을 진행시키고 생성되는 molondialdehyde를 분석한 결과 사포닌 분획은 ${\alpha}$-tocopherol의 항산화작용을 상승적으로 증가시켰다. 그리고 ${\alpha}$-tocopherol의 항 산화작용에 상승적 효과는 반응액에서의 인삼 사포닌 분획의 농도가 $10^{-5}\%$ 전후에서 특히 현저하였다. 술로 과산화물을 유발케 한 쥐에게 ${\alpha}$-tocopherol만을 또는 ${\alpha}$-tocopherol과 인삼 사포닌 분획의 혼합물을 경구투여하고 일정 시간 후에 간의 과산화 지질을 thiobarbituric acid 방법으로 분석한 결과 사포닌 분획이 동물체내에서도 ${\alpha}$-tocopherol의 항 산화작용을 크게 촉진시키는 것으로 관찰되었다. 또한 사포닌 분획은 ${\alpha}$-tocopherol의 흡수를 촉진시키는 것으로 보고되고 있으며 본 실험에서도 이것을 확인하였고 이와 같은 사포닌 분획의 ${\alpha}$-tocopherol흡수 촉진은 ${\alpha}$-tocopherol의 항 산화작용을 더욱 효과적으로 촉진 시킬 것으로 생각된다.

• Current Optics and Photonics
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• 제2권1호
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• pp.90-95
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• 2018

Stimulated polariton scattering from the $B_1$-symmetry modes of a $KNbO_3$ crystal to generate a terahertz wave (THz-wave) with a noncollinear phase-matching scheme is investigated. The frequency-tuning characteristics of the THz-wave by varying the phase-matching angle and pump wavelength are analyzed. The expression for the effective parametric gain length under the noncollinear phase-matching condition is deduced. Parametric gain and absorption characteristics of the THz-wave in $KNbO_3$ are theoretically simulated. The characteristics of $KNbO_3$ for a terahertz parametric oscillator (TPO) are compared to those of $MgO:LiNbO_3$. The analysis indicates that $KNbO_3$ is an excellent optical crystal for a TPO, to enhance the THz-wave output.

• Current Optics and Photonics
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• 제2권3호
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• pp.261-268
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• 2018

Stimulated polariton scattering (SPS) from the $A_1$ transverse optical (TO) modes of $BaTiO_3$ bulk crystal generating a terahertz (THz) wave with the noncollinear phase-matching (NPM) condition is theoretically investigated. To our best knowledge, this is the first report on THz wave generation from $BaTiO_3$ bulk crystal via SPS. Phase-matching (PM) characteristics in the NPM configuration are analyzed. Effective parametric gain lengths for the Stokes and THz waves in the NPM configuration are calculated. The effective parametric gain coefficient and absorption coefficient of the THz wave in $BaTiO_3$ are theoretically simulated. The THz phonon flux densities generated via SPS in $BaTiO_3$ are theoretically calculated by solving the coupled wave equations under the NPM condition. The PM characteristics and THz-wave parametric gain characteristics in $BaTiO_3$ are compared to those in $MgO:LiNbO_3$. The results of the analysis indicate that $BaTiO_3$ is an attractive optical crystal for efficient THz wave generation via SPS.

• Current Optics and Photonics
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• 제3권4호
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• pp.342-349
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• 2019

We present a theoretical research concerning terahertz (THz) wave generation with $KTiOPO_4$ (KTP) by collinear phase matching (CPM) stimulated polariton scattering (SPS). Both CPM and corresponding nonzero nonlinear coefficients can be simultaneously realized with $s{\rightarrow}f+f$ in yz plane, $s{\rightarrow}f+s$ with ${\theta}$ < ${\Omega}$ in xz plane and $s{\rightarrow}f+f$ with ${\theta}$ < ${\Omega}$ in xz plane. The effective nonlinear coefficients including electronic nonlinearities and ionic nonlinearities are calculated. Based on the parameter values of refractive indices, absorption coefficients and effective nonlinear coefficients, we simulate THz wave intensities generated with CPM SPS by solving coupled wave equations and give the relationship among the maximum THz wave intensity, optimal crystal length and the angle ${\theta}$. The calculation results demonstrate that CPM SPS with KTP can generate THz waves with high intensities and quantum conversion efficiencies.

• Journal of the Korean Physical Society
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• 제73권9호
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• pp.1377-1384
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• 2018

Accurate measurement of the absorbed dose and the effective dose is required in dental panoramic radiography involving relatively low energy with a rotational X-ray tube system using long exposures. To determine the effectiveness of measuring the irradiation by using passive dosimetry, we compared the entrance skin doses by using a radiophotoluminescent glass dosimeter (RPL) and an optically stimulated luminescence detector (OSL) in a phantom model consisting of nine and 31 transverse sections. The parameters of the panoramic device were set to 80 kV, 4 mA, and 12 s in the standard program mode. The X-ray spectrum was applied in the same manner as the panoramic dose by using the SpekCalc Software. The results indicated a mass attenuation coefficient of $0.008226cm^2/g$, and an effective energy of 34 keV. The equivalent dose between the RPL and the OSL was calculated based on a product of the absorbed doses. The density of the aluminum attenuators was $2.699g/cm^3$. During the panoramic examination, tissue absorption doses with regard to the RPL were a surface dose of $75.33{\mu}Gy$ and a depth dose of $71.77{\mu}Gy$, those with regard to the OSL were surface dose of $9.2{\mu}Gy$ a depth dose of $70.39{\mu}Gy$ and a mean dose of $74.79{\mu}Gy$. The effective dose based on the International Commission on Radiological Protection Publication 103 tissue weighting factor for the RPL were $0.742{\mu}Sv$, $8.9{\mu}Sv$, $2.96{\mu}Sv$ and those for the OSL were $0.754{\mu}Sv$, $9.05{\mu}Sv$, and $3.018{\mu}Sv$ in the parotid and sublingual glands, orbit, and thyroid gland, respectively. The RPL was more effective than the OSL for measuring the absorbed radiation dose in low-energy systems with a rotational X-ray tube.