• 대한방사선방어학회:학술대회논문집
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• 2011.04a
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• pp.78-79
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• 2011

• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.1
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• pp.9-15
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• 2011

This paper suggested the fast and easy method of the dielectric constant measurement for planar dielectrics using a microstrip line. The complex permittivity and permeability were presented by the first reflection and transmission coefficient which were derived from the scattering parameters. This method was verified by the measurement of a known planar dielectric using a microstrip line. This method can be applied to the dielectric constant measurement of unknown planar dielectric.

• Journal of the Korean Society of Radiology
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• v.17 no.6
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• pp.889-896
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• 2023

Changes in the energy spectrum were analyzed using ^99mTc as a point source and a scattering phantom, and the shielding effect of the lead apron according to the changed gamma ray energy was evaluated. In the gamma ray energy spectrum of the scattering phantom, the photo peak area decreased and the compton scattering area increased compared to the point source. The coefficients for each energy range according to the change in the shape of the gamma ray source showed a reduction rate of up to 66.1 % at a distance of 20 cm compared to the coefficient of the point source, and in the compton scattering area, the coefficient of the scattering phantom was 122.2 % at a distance of up to 40 cm compared to the coefficient of the point source. In the difference in shielding rate according to the distance between the source and the scattering phantom using a gamma camera, the photo peak area showed similar results, but in the Compton scattering area, the shielding rate of the scattering phantom at a distance of 20 cm increased by 29.2 % compared to the shielding rate of the point source. As the distance increased, the difference in shielding rate decreased. In measuring the shielding rate of the lead apron using a radiation dosimeter, the difference in the shielding rate of the scattering phantom was up to 15.3 %, and as the distance increased, the difference in the shielding rate between the two sources decreased. The shielding rate of the lead apron of the scattering phantom is higher than that of the point source, and the effectiveness of the lead apron increases as the distance to the source increases. As a result, wearing a lead apron when directly confronting a patient who has injected radioactive pharmaceuticals is expected to be helpful in reducing radiation exposure.

• Journal of Biomedical Engineering Research
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• v.18 no.4
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• pp.499-505
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• 1997

A non-invasive technique to measure absorption and scattering coefficients was investigated The reflected backscattered light from the surface of phantom and biological tissue was obtained by using a time-correlated single photon counting system in pico-second time domain. The absorption and scattering coefficients were acquired by the time of peak and asymptotic behavior of the time-resolved reflectance curve and agreed well the ones that is obtained with deconvolution method It was found that the approximation method was good for biological medium to calculate optical properties due to its convenience and accuracy.

• Proceedings of the Acoustical Society of Korea Conference
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• 1992.11a
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• pp.69-76
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• 1992

섬유강화 복합재료의 동탄성계수와 감쇠특성을 규명하기 위하여 랜덤하게 분포된 무한 실린더 형상의 산란체를 가진 점탄성 매질내에서 , 축방향으로 분극되어 조화 운동을 하는 탄성파의 전파에 관하여 연구하였다. 다중 산란에 관한 이론으 이용하여 매질내에서의 파동전파 특성을 내포하는 분산관계식을 얻었다. 다중산란에 의한 실린더간의 상호작용을 수식화하기위하여 필요한 실린더의 쌍분포함수는 몬테카를로 모의 실험을 이용하여 구하였다. 수치적으로 구한 감쇠계수 및 유효전단강성을 주파수와 체적율의 함수로 제시하였다. 또한 감쇠계수의 주파수에 따른 변화에 있어서, 저주파에서는 매질의 점탄성 손실이 지배적이며, 고주파수로 갈수록 다중산란에 의한 손실이 지배적인 것으로 나타났다.

• Progress in Medical Physics
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• v.13 no.1
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• pp.37-43
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• 2002

Effect of scatter media materials and thickness, located between radioactivity and small gamma camera, on imaging characteristics was evaluated. The small gamma camera developed for breast imaging was consisted of collimator, NaI(T1) crystal(60$\times$60$\times$6 ㎣), PSPMT(position sensitive photomultimplier tube), NIMs and personal computer. Monte Carlo simulation was performed to evaluate the system sensitivity with different scatter media thickness(0~8 cm) and materials(air and acrylic) with parallel hole collimator and diverging collimator. The sensitivity and spatial resolution was measured using the small gamma camera with the same condition applied to the simulation. Counts was decreased by 10%(air) and 54%(acryl) with the parallel hole collimator and by 35%(air) and 63%(acryl) with the diverging collimator. Spatial resolution was decreased as increasing the thickness of scatter media. This study substantiate the importance of a gamma camera positioning and the minimization of the distance between detector and target lesion in the clinical application of a gamma camera.

• Korean Journal of Poultry Science
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• v.29 no.1
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• pp.19-23
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• 2002

This studs was conducted to investigate the effects of dietary carbohydrase (multi-enzyme: $\alpha$-galactosidase and mannanase) on egg quality and nutrient digestibility in laying hens. One hundred forty four, 47-wk-old, ISA Brown commercial layers were used in a 28-d feeding trial after a 7-d adjustment period. Dietary treatments were 1) CON(basal diet), 2) ME 0.1 (basal diet +0.1% multi -enzyme), 3) ME 0.2 (basal diet + 0.2% multi-enzyme). Fer overall Period, hen-day egg Production, egg weight, egg shell breaking strength and egg shell thickness were not influenced by the multi-enzyme. As the adding levels of multi-enzyme increased in the diet, egg Yolk color and egg Yolk index tended to increase with significant differences. Digestibility of DM was not affected by multi-enzyme. However, digestibility of N increased significantly as the concentration of multi-enzyme in the diet was increased. In conclusion, supplemental carbohydrase in laying hen diets nay have some roles in improving the egg Yolk color and N digestibility.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.7
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• pp.204-210
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• 2016

This paper presents an experimental analysis of the growth and oxidation processes of soot particles generated in an isooctane diffusive laminar flame due to incomplete combustion. The effects of iron-based diagnostics were employed to measure the elastic scattering light from soot particles in a flame at different flame heights, and the differential scattering coefficients were calculated through a calibration process. The growth and oxidation of soot particles in flame was investigated by comparing differential scattering coefficients, and the soot volume fraction was seen to decrease in the soot oxidation process. In the same manner, the differential scattering coefficients were calculated for iron-based fuel-additive seeded flame, and these coefficients were revealed to be smaller than those obtained in the fuel-additive unseeded flame. In addition, transmission through the radial direction of the flame was measured, and transmission in the soot oxidation regime was approximately 5% higher for the seeded flame. The propensity of the data coincided well with the differential scattering coefficients, and it can be concluded that the iron component of the fuel additive plays a crucial role as a catalyst, which eventually enhanced soot particle oxidation.

• Korean Journal of Poultry Science
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• v.3 no.1
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• pp.19-28
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• 1976

본 시험은 1967년 4부터 5월에 걸쳐 실시되었으며 공시자계수는 270수, 공시난수는 981개이었다. 공시정액은 혼합 사용하였고 주정부위는 질내 2-3cm 하였다. 조조 5시부터 각시각별로 9개구를 설정하여 1수당 0.04$m\ell$씩 1회 주정하여 수정상황을 관찰하였던 바 그 결과를 요약하면 다음과 같다. 1, 주정익일 수정율은 5시구 25%, 6시구 21.7%, 7시구 21.1%, 9시구 15.8%이었으며, 기타 시각에는 전혀 얻어지지 않았다. 2. 질내 2-3cm 부위 주정에 의하여 익일수정란을 많이 얻으려면 산란전주정의 경우와 휴산당일 주정의 경우 산란 또는 배란전 최소 3-5시간의 시차를 두고 주정하여야 된다. 질내 6-7cm 부위에 주정할 경우보다 1-2시간의 시차를 더 요한다. 산란후 주정의 경우에는 익일수정란이 전혀 얻어지지 않았다. 3. 1주간의 주정시각별 수정율은 오전의 평균은 29.9%, 오후의 평균은 55.2%로서 양자사이에 고도의 유의차가 인정된다. 4. 산란전(오전)에 주정하여 높은 일주간 수정율을 얻으려면 주정익일 경우와 마찬가지로 최소 3-5시간 이상의 시차를 두고 주정하여야 된다. 이에 적합한 주정시각은 오전 3-5시로 추찰된다. 5. 산란후 주정의 경우는 산란후 2시간 이상의 시차에서 높은 1주간 수정율이 얻어졌다. 6. 휴산당일 주정의 경우에 있어서의 수정율은 오전의 평균은 32.6%, 오후의 평균은 51.5%로서 양자 사이에 고도의 유의차가 인정된다. 7. 종합적으로 보아 오후 3시경부터 일몰시까지가 실지 인공수정에 있어 가장 적당한 주정시각임이 밝혀졌다. (중략)

• Bulletin of the Korean Space Science Society
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• 2011.04a
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• pp.31.3-31.3
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• 2011

달의 양방향 분포 함수는 Hapke에 의하여 처음 이론적 모델이 만들어졌고, 이후 Foote에 의해 아폴로 11호의 달 토양 샘플 10084의 양방향 분포 함수가 측정된 바 있다. 이 연구에서는 실제 크기의 달의 표면에 Hapke의 양방향 분포 함수를 적용하여 광학 모델은 개발하였다. 달 표면의 산란특성 중 반 무한하고 매끄러운 지면에 적용되는 후방산란 효과와 산란각에 따른 위상 함수가 적용된 모델이 사용되었으며, 위상함수로는 Henyey-Greenstein 함수가 사용되었다. 달의 3D 모델에 사용된 매개 변수는 Foote가 측정한 Hapke의 변수를 따랐으며 달의 단일 산란 알베도는 w=0.33, 핫스팟의 넓이는 h=0.017, Legendre 다항 계수인 b와 c에는 각각 b=0.308, c=0.425의 값이 사용되었다. 구성된 달의 양방향 분포 함수를 이용한 통합적 광선 추적 수치 모사 결과, 달 반사광의 복사 휘도율은 1차 근사 해석적 방법을 이용한 계산 결과의 복사 휘도율과 측정 오차 범위 이내의 오차를 보였다.