• Title/Summary/Keyword: 실측실험

Search Result 653, Processing Time 0.029 seconds

Dose Distribution Study for Quantitative Evaluation when using Radioisotope (99mTc, 18F) Sources (방사성 동위원소 (99mTc, 18F) 선원 사용 시 인체 내부피폭의 정량적 평가를 위한 선량분포 연구)

  • Ji, Young-Sik;Lee, Dong-Yeon;Yang, Hyun-Gyung
    • Journal of the Korean Society of Radiology
    • /
    • v.16 no.5
    • /
    • pp.603-609
    • /
    • 2022
  • The dose distribution in the human body was evaluated and analyzed through dosimetry data using water phantom, ionization chamber and simulated by Monte Carlo simulation for 99mTc and 18F sources, which are frequently used in the nuclear medicine in this study. As a result of this study, it was found that the dose decreased exponentially as the distance from the radioisotope increased, and it particularly showed a tendency to decrease sharply when the radioisotope was separated by 5 cm. It means that a large amount of dose is delivered to an organ located within 4 cm of source's movement path when a source uptake in the human body. Numerically, it was formed in the rage of 0.16 to 2.16 pC/min for 99mTc and 0.49 to 9.29 pC/min for 18F. In addition, the energy transfer coefficient calculated using the result was found to be similar to the measured value and the simulation value in the range of 0.240 to 0.260. Especially, when the measured data and the simulation value were compared, there was a difference is within 2%, so the reliability of the data was secured. In this study, the distribution of radiation generated from a source was calculated to quantitatively evaluate the internal dose by radioisotopes. It presented reliable results through comparative analysis of the measurement value and simulation value. Above all, it has a great significance to the point that it was presented by directly measuring the distribution of radiation in the human body.

An Esitimation of Lognitudinal Dispersion Coefficient in Natural Stram Using Hydraulic Model (수리모형을 이용한 자연하천에서 종확산계수 추정)

  • Yun, Se-Ui;Han, Geon-Yeon;Han, Jeong-Seok;Kim, Jeong-Su
    • Journal of Korea Water Resources Association
    • /
    • v.33 no.4
    • /
    • pp.407-417
    • /
    • 2000
  • To estimate the longitudinal dispersion coefficient at the downstream of Jungrang-River, the undistorted 1/20 scale hydraulic model was used in this study. Experiments were conducted for dry season discharge, and Rhodamine B was used as a tracer. The relationship curve between concentration and conductivity of Rhodamine B was otained by laboratory test, and the conductivity which was measured in hydraulic model was converted to concentration using this curve. The longitudinal dispersion coefficient was calculated using the relationship between the peak concentration and the time to peak concentration. The results of this study were compared with the calculated values by the empirical equations for the longitudinal dispersion coefficient and with the field data. The results of comparison show that Parker's equation underestimates, and Liu'g equation and Iwasa and Aya's one overestimate, and McQuivey and Keefer's equations, Fischer's one, Magazine's one, and Seo and Cheong's one predict relatively well. The measured data sets were relatively close to the observed ones in natural river. The longitudinal dispersion coefficient at the downstream of Jungrang-River was estimated $10\textrm{m}^2/s$.

  • PDF

Mid Frequency Band Reverberation Model Development Using Ray Theory and Comparison with Experimental Data (음선 기반 중주파수 대역 잔향음 모델 개발 및 실측 데이터 비교)

  • Chu, Young-Min;Seong, Woo-Jae;Yang, In-Sik;Oh, Won-Tchon
    • The Journal of the Acoustical Society of Korea
    • /
    • v.28 no.8
    • /
    • pp.740-754
    • /
    • 2009
  • Sound in the ocean is scattered by inhomogeneities of many different kinds, such as the sea surface, the sea bottom, or the randomly distributed bubble layer and school of fish. The total sum of the scattered signals from these scatterers is called reverberation. In order to simulate the reverberation signal precisely, combination of a propagation model with proper scattering models, corresponding to each scattering mechanism, is required. In this article, we develop a reverberation model based on the ray theory easily combined with the existing scattering models. Developed reverberation model uses (1) Chapman-Harris empirical formula and APL-UW model/SSA model for the sea surface scattering. For the sea bottom scattering, it uses (2) Lambert's law and APL-UW model/SSA model. To verify our developed reverberation model, we compare our results with those in Ellis' article and 2006 reverberation workshop. This verified reverberation model SNURM is used to simulate reverberation signal for the neighboring seas of South Korea at mid frequency and the results from model are compared with experimental data in time domain. Through comparison between experiment data and model results, the features of reverberation signal dependent on environment of each sea is investigated and this analysis leads us to select an appropriate scattering function for each area of interest.

Far Field Test on Electromagnetic Wave Absorber for X-Band Radar (X-Band Radar용 전파흡수체의 실장실험)

  • 김동일;안영섭;정세모
    • Proceedings of the Korean Institute of Navigation and Port Research Conference
    • /
    • 1993.10b
    • /
    • pp.31-43
    • /
    • 1993
  • 전파흡수체의 전파흡수능 측정방법은 기본적으로 다양한 마이크로파 측정법이 이용될수 있지만 레이다용 전파흡수체의 경우 전파의 주파수가 높기 때문에 파장이 짧아서 측정오차가 큰 문제점이 있다. 따라서 한국해양대학교 마이크로파연구실에서는 전파흡수체의 전파흡수능을 실험적으로 간단히 측정할 수 있게 하기 위한 20mm$\Phi$동축관 샘플홀더 및 Type-N connector로부터 20mm$\Phi$동축관으로의 변환 Adaptor를 제작하여 전파흡수체의 설계 및 특성(전파흡수능) 평가에 사용할 수있게 한 바 있으며 또 구형도파관을 이용한 재료정수 측정법을 채용하여 시료의 형상등의 영향을 적게 받는 실측 방법에 관하여 검토하여왔다 본 논문에서는 그동안 실험실적으로 설계하여 온 X-Band Radar용 전파흡수체를 실용의 상태에 가까운 반사전력법에 의하여 그 성능을 예비평가하고 실제의 target를 제작하여 X-Band Radar로 실장실험한 결과에 대하여 보고하고자 한다.

  • PDF

Development of Displacement Estimation Technique for Bridges Located under Poor Measurement Circumstances (계측이 어려운 환경에 가설된 교량의 변위 추정 기술 개발)

  • Jeon, Junchang;Lee, Heehyun
    • Journal of the Korean Society for Railway
    • /
    • v.19 no.6
    • /
    • pp.755-764
    • /
    • 2016
  • In this paper, to verify the field application of a displacement estimation technique based on the relationship between displacement and strain, static and dynamic field load test are performed on three-span continuous real bridge structures. The superstructure types of the test bridges are IPC girder highway bridge and steel box girder AGT bridge. LVDTs and strain gauges are attached to them; then, the responses due to test vehicle are measured. To obtain the displacement-strain relationship of the test bridges, the bridges are modeled as grillage system with 6 DOFs for the purpose of structural analyses. Static and dynamic displacements, which are estimated using both the calculated displacement-strain relationship and the measured strain signal, agree well with the values measured by LVDT. This study demonstrates that the displacement estimation technique using the strain signal can be effectively applied to the displacement measurement of bridge structures that cross rivers/roads/railways or have high clearance.

Evaluation of the Apron Effectiveness during Handling Radiopharmaceuticals in PET/CT Work Environment (PET/CT 업무 환경에서 선원 취급 시 Apron의 실효성 평가)

  • Cho, Yong-In;Ye, Soo-Young;Kim, Jung-Hoon
    • Journal of radiological science and technology
    • /
    • v.38 no.3
    • /
    • pp.237-244
    • /
    • 2015
  • Health professionals in nuclear medicine were known that they get high radiation exposure. To reduce radiation exposure, using shielding materials is needed. In this study, we analyzed the shielding effect about apron during 18F-FDG treatment by using simulation based on Monte Carlo techniques and actual measurement. As a result, absorbed dose distribution of organ varies with handling position of the source. Dose reduction ratio by lead thickness of apron tended to decease, when handling position of the source come close to organ and away from radiation source for simulation. In the case of actual measurement with the dosimetry device, It showed that mean spatial dose distribution was different due to characteristics of dosimetry device. However, spatial dose rate was exponentially reduced according to distance with increasing lead content.

Bending strength assessment of Larix logs by nondestructive evaluation techniques (비파괴 시험방법을 이용한 낙엽송재 원목의 휨강도 특성 평가)

  • 박준철;홍순일
    • Journal of Korea Foresty Energy
    • /
    • v.22 no.2
    • /
    • pp.60-68
    • /
    • 2003
  • In forest products industry, a variety of nondestructive evaluation techniques are now being used to assess the mechanical properties of structural lumber. Ultrasonic and longitudinal vibration technique are frequently used to assess the modulus of elasticity(MOE) of lumber. The objective of this research was to evaluate the MOE and modulus of rupture(MOR) of small-diameter of Larix log(Larix kaempferi Carr.), using these techniques. In this study, 50 small-diameter logs were nondestructiveively evaluated. The dynamic modulus of elasticity(Eu) of the logs was first evaluated, using an ultrasonic method. After ultrasonic tests, the logs were measured using a longitudinal vibration technique(Ev). Static bending test was then performed on the logs to obtain the static modulus of elasticity(Es) and modulus of rupture of these logs. In general, the dynamic MOE (Ev) of logs was closely co..elated with the stati, MOE for log. Based on the results of these experiments, it can be concluded that small-diameter Larix logs can be successfully evaluated by Ultrasonic and longitudinal vibration technique. The experimental results indicated that the ultrasonic technique is effective to the log, which contains many knots. The longitudinal vibration technique is effective to the log, in which many cracks are included.

  • PDF

Measurement and Analysis of Electric Filed Distributions under 154[kV] Overhead Tranamission Lines (154[KV] 가공송전선로 아래에서 전장분포의 측정과 분석)

  • 이복희;이정기;안창환;이경옥;박동화;곽희로;송진호
    • The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
    • /
    • v.11 no.1
    • /
    • pp.92-98
    • /
    • 1997
  • In this paper, the results of the measurement and analysis of extremely low freqency(ELF) eletric field in the vicinity of 154[kV] overhad transmission lines have been described. The planar-type electric field sensor has been fabricated by three dimensional structure with special consideration of taking the power frequency and lower components. The calibration experiments have been carried out according to the procedures of IEEE recommendation. The electric field measuring system has the frequency bandwidth of 7[Hz] to 2.7[MHz] and the response sensitivity of 0.094[mV/V/m]. Also the practical measurements of electric field under an 154[kV] double corcuit overhead transmission lines have been made abd abalyzed. It was known that the lateral electric field profiles under an 154[kV] double circuit overhead transmission lines show the asymmetrical distributions owing to the environmental metal frame structures and their maximum electric field magnitude is less than 3[kV/m]. It can be concluded that the measured results of the electric fields satisfy with all limits or guide -lines of the various authorized international institutes' recommendations.

  • PDF

An Experimental Study on the characteristics of Flow and Bed Topography with Changing Bed Material in a Curved Channel (만곡수로에서 하상재료 변화에 따른 흐름과 하상변동 특성에 관한 실험적 연구)

  • Jeong, Jae-Uk;Yun, Se-Ui
    • Journal of Korea Water Resources Association
    • /
    • v.31 no.3
    • /
    • pp.291-301
    • /
    • 1998
  • The objective of this study is to analyze the characteristics of flow and bed topography with changing bed material in a 180-degree, with constant-radius curved experimental channel. Sand($D_{50}$ = 0.56 mm, s = 2.65) and anthracite($D_{50}$ = 0.26 mm, s = 1.54) were selected as bed materials. The maximum scour depth was found to be about two times for the mean flow depth at the outer bank of bend angle $30^{\circ}~60^{\circ}$, and in case of anthracite, it was found upper part of bend angle $5^{\circ}~15^{\circ}$ than that of sand. Regardless of bed materials the path of maximum streamwise velocity is skewed inwards in the upper part of the bend, the maximum velocity shifts outwards, and it lagged downward as bed roughness increases. The maximum skewed angle of flow grows faster in the smooth bottom than in the rough one, and its value also increases. The secondary flow in anthracite bottom was measured larger than that of sand one, and two cells of secondary flow was found in this experiment.

  • PDF

A Study on the Estimating the Ultra-High Strength Concrete using Rock Test Hammer (Rock Test Hammer를 사용한 초고강도 콘크리트 강도추정에 관한 기초적 연구)

  • Nam, Kyung-Yong;Kim, Seong-Deok;Choi, Suk;Lee, Young-Do
    • Journal of the Korea Institute of Building Construction
    • /
    • v.19 no.3
    • /
    • pp.229-237
    • /
    • 2019
  • This study examines the estimation of strength through a ultra-high strength concrete mock-up specimen using the rock compressive strength test hammer. According to the test result, the commonly used strength estimation formulae showed differences among them when the data of this test were applied. In additional, it show that these formulae underestimated the actual measurements further when the compressive strength was 30MPa or greater and deviated the distribution range of actual measurements in all strength ranges. The rock test hammer showed a higher correlation than type N Schmidt hammer regardless of the direction of hit for each type of W/B and the inclusion of coarse aggregate, and mortar showed a little higher correlation than concrete. As a result, it can be suggested that the coefficient of variation and the standard deviation of the mortar(2.26%/1.36) are lower than those of the concrete(4.06%/2.5), and the smaller the size of the coarse aggregate, the smaller the coefficient of variation and the more accurate the value.