• Journal of Biomedical Engineering Research
• /
• v.38 no.5
• /
• pp.256-263
• /
• 2017

By using the buildup characteristics of the radiophotoluminescence glass dosimeter(RPLGD), it is aimed to help the measurement of the accurate dose by measuring the radiation dose according to the time of the glass element. Five glass elements were arranged on the table and the source to image receptor distance(SID) was set to 100 cm for the build-up radiation dose measurement of the fluorescent glass dosimeter glass element(GD-352M). Radiation doses and saturation rates were measured over time according to irradiation time, with the tube voltage (30, 60, 90 kVp) and tube current (50, 100 mAs) Repeatability test was repeated ten times to measure the coefficient of variation. The radiation dose increased from 0.182 mGy to 12.902 mGy and the saturation rate increased from 58.3% with increasing exposure condition and time. The coefficient of variation of the glass elements of the fluorescent glass dosimeter was ranged from 0.2 to 0.77 according to the X - ray exposure conditions. X - ray exposure showed that the radiation dose and saturation rate were increased with buildup characteristics, and degeneration of glass elements was not observed. The reproducibility of the variation coefficient of the radiation generator was included within the error range and the reproducibility of the radiation dose was excellent.

• Journal of the Korea Computer Industry Society
• /
• v.4 no.12
• /
• pp.943-952
• /
• 2003

GDS(Grating automatic Drawing System), which is an automatic design system of metal products called grating, is a system that produces various detailed drawings on the basis of information within a Plan Drawing that represents layout of the gratings such as locations, shapes, directions, etc. However, automatically produced drawings by GDS do not fully satisfy the standard of the general dimension marking method used among the layout designers. The lack of this standard quality mainly results from the fact that overlapping among dimension markings appears frequently. To solve the overlapping problem we applied the rule-based expert system which uses the expert's knowledges and facts to solve the problems. The rules for the expert system are designed based on the expertise of skilled layout designers within the grating production lines.

• Proceedings of the Korean Society Of Semiconductor Equipment Technology
• /
• 2007.06a
• /
• pp.34-38
• /
• 2007

청, 황 2-파장 발광층의 구성에서 청색층으로 GDI602를, 황색층으로 GD1602:Rubrene(10%)를 사용하여 2-파장 백색 유기발광다이오드(WOLED)를 제작하고 이들의 특성을 분석하였다. 실험에서는 GDI602:Rubrene (10%)-황색층의 두께를 $220\{AA}$으로 일정하게 두고, GDI602-청색층의 두께를 달리하여 소자들을 제작하였다. 제작된 소자들의 발광 스펙트럼 특성으로는 GDI602 층의 두께에 따라 중심파장의 위치는 거의 일정하나 2-파장 사이의 상대적 세기가 변화되었으며, GDI602 층의 두께가 얇아질수록 황색파장의 상대적 세기가 강해지는 것을 볼 수 있었다. GDI602 층이 $60{\AA}$인 소자는 11V, $70{\AA}$인 소자는 9V, $80{\AA}$인 소자는 8V, $90{\AA}$인 소자는 7V 에서 순수 백색광(x=0.33, y=0.33)에 가까운 발광 특성을 나타내었다. 또한 GDI602 층의 두께에 따른 효율과 휘도는 백색발광 조건에서 각각 0.51m/W와 $3650cd/m^2(60{\AA})$, 0.61m/W와 $1050cd/m^2(70{\AA})$, 0.91m/W와 $490cd/m^2(80){\AA}$, 1.61m/W와 $250cd/m^2(90){\AA}$을 나타내었다.

• 제어로봇시스템학회:학술대회논문집
• /
• 2005.06a
• /
• pp.2254-2259
• /
• 2005

In this paper, we propose a wavelet based fuzzy neural network(WFNN) based direct adaptive control scheme for the solution of the tracking problem of mobile robots. To design a controller, we present a WFNN structure that merges advantages of neural network, fuzzy model and wavelet transform. The basic idea of our WFNN structure is to realize the process of fuzzy reasoning of wavelet fuzzy system by the structure of a neural network and to make the parameters of fuzzy reasoning be expressed by the connection weights of a neural network. In our control system, the control signals are directly obtained to minimize the difference between the reference track and the pose of mobile robot using the gradient descent(GD) method. In addition, an approach that uses adaptive learning rates for the training of WFNN controller is driven via a Lyapunov stability analysis to guarantee the fast convergence, that is, learning rates are adaptively determined to rapidly minimize the state errors of a mobile robot. Finally, to evaluate the performance of the proposed direct adaptive control system using the WFNN controller, we compare the control performance of the WFNN controller with those of the FNN, the WNN and the WFM controllers.

• Nuclear Engineering and Technology
• /
• v.52 no.7
• /
• pp.1367-1379
• /
• 2020

The small modular sodium-cooled fast reactor (SMSFR) is an important component of Generation-IV reactors. The objective of this work is to improve the reactivity control in SMSFR by using innovative systems, including burnable poisons and optimized control rods. SMSFR with MOX fuel usually exhibits high burnup reactivity loss that leads to high excess reactivity and potential fuel melting in control rod withdrawal (CRW) accidents, which becomes an important constraint on the safety and economic efficiency of SMSFR. This work applies two types of burnable poisons in a SMSFR to reduce the excess reactivity. The first one homogenously loads minor actinides in the fuel. The second one combines absorber and moderators in specific assemblies. The influence of burnable poisons on the core characteristics is discussed and integrated into the analysis of CRW accidents. The results show that burnable poisons improve the safety performance of the core in a significant way. Burnable poisons also lessen the demand for the number, absorption ability, and insertion depth of control rods. Two optimized control rod designs with rare earth oxides (Eu₂O₃ and Gd₂O₃) and moderators are compared to the conventional design with natural boron carbide (B₄C). The optimized designs show improved neutronic and safety performance.

• Journal of the Korean Ceramic Society
• /
• v.44 no.12
• /
• pp.715-719
• /
• 2007

STS444 with or without $La_{0.9}Sr_{0.1}MnO_3$ (LSM)-coating was contacted to $La_{0.6}Sr_{0.4}Co_{0.2}Fe_{0.8}O_3$ (LSCF) cathode on various electrolyte materials and the polarization resistance $(R_p)$ was measured by impedance spectroscopy. By making a symmetric half-cell and contacting only one side of the cathode with the interconnect, the effect of chromium (Cr) poisoning was separated from the aging effects. When the LSCF cathode was contacted with LSM-coated STS (stainless steel), $R_p$ of LSCF was lower than that contacted with the uncoated STS. Impedance patterns measured for the working electrode (W.E.), the counter electrode (C.E.) at $600^{\circ}C$ in air were analyzed. Normalized data of net Cr effect showed that $Ce_{0.9}Gd_{0.1}O_2$ (GDC) electrolyte is more tolerant to the chromium poisoning than $La_{0.9}Sr_{0.1}Ga_{0.8}Mg_{0.2}$ (LSGM) or 8 mol% $Y_2O_3-doped$ $ZrO_2$ (YSZ) electrolytes.

• Progress in Superconductivity and Cryogenics
• /
• v.19 no.2
• /
• pp.48-52
• /
• 2017

Discrepancy between a power supply current and an actual "spiral" coil current makes the conventional 4-probe measurement of a critical current ($I_c$) of a no-insulation (NI) high temperature superconductor (HTS) coil inaccurate and time-consuming. This paper presents a fast and accurate approach for $I_c$ measurement of NI HTS coils. With an NI HTS coil energized at a constant ramping rate, a complete analytic expression for the spiral coil current was obtained from a first-order partial differential equation that derived from an equivalent circuit model of the NI coil. From the analytic solution, both spiral coil current and radial leak current can be obtained simultaneously, which enables fast and accurate measurement of the NI coil $I_c$. To verify the proposed approach, an NI double-pancake (DP) coil, wound with GdBCO tapes of $6mm{\times}0.1mm$, was constructed and its $I_c$ was repeatedly measured with various ramping rates in a bath of liquid nitrogen at 77 K. The measured results agreed well with the calculated ones, which validates the proposed approach to measure $I_c$ of an NI HTS coil.

• The Korean Journal of Ceramics
• /
• v.5 no.4
• /
• pp.375-378
• /
• 1999

In tho XRD study of $56ZrF_4 \cdot34BaF_2 \cdot4AIF_3 \cdot(6-x)LaF_3 \cdotxLnF_3$ glassdLn=Ce, Nd, Gd, Th), halo pattern charactarktic fo an amorphous sample appeared. When the halo peak angle ($\theta_p$) was converted into a wavenumber with $Qp=4\pi sinG\pi/\lambda(\lambda$ is the wavolongth of the radialion used), it was found that the Qp values varied almost liuearly with the concentration 01 $LnF_3$. The emissiou spect1.a of $Ce^{3-}$-containing fluoride glasses nnder 273 nm excitation had a peak maximum at ea. 300 nm $(Ce^{3+}$ 5d-4f- transition). The maximal intensity of the fluorescence was observed when the $CeF_3$, content was extremely low (ca. 1 mol%j. DTA measurement revealed tbat these fluoride glasses had two crystallization temperatures. In $56ZrF_4. 34BaF_2. 4NF_3. (6-x)LaF_3 .xNdF_3$ glasses, the actmation energies of crystallization obtained from a Kssinger plot were 1.7 and 5.0 eV for the glass with x=2, and 1.9 and 5.6 eV for the glass with x=4.

• Environmental Mutagens and Carcinogens
• /
• v.22 no.2
• /
• pp.125-132
• /
• 2002

To evaluate the modifying effect of Kwao Kreu, Pueraria mirifica (PM) well-known as a rejuvenating folk medicine from Thailand, peri- and post-natal studies were carried out in rats. PM extract was administered to pregnant Sprague Dawley (SD) rats by oral gavage from gestation 6 (GD 6) to postnatal day 21 (PND 21). The amount of administered in this study was 0.042, 0.42 and 4.2 mg/kg/day, respectively. There were no treatment related changes of dams in deaths, clinical signs, and parturition. Treatment related changes in body weight, food consumption and lactation of dams were not observed. F1 fetuses in external abnormality, physical development, reflex/sensory functions and behavioral development were not found. No adults and F1 fetuses in organ weight was found with the exception of vagina and uterus of F1 fetuses. The results showed that PM extract, up to 4.2 mg, had no adverse effects on the peri- and post-natal development of rats. Therefore, PM extract has no adverse effects on peri- and post-natal development of rats.

• Proceedings of the KSMRM Conference
• /
• 2001.11a
• /
• pp.171-171
• /
• 2001

목적： 뇌 자기공명영상에서 Z-score를 이용한 관류 영상과 조영전후의 감산에 의한 역동 영상의 관류 양상을 비교 관찰 하고자 한다. 대상 및 방법： 뇌 자기공명영상에서 이상 소견이 없는 젊은 환자 1명, Moya moya 환자 1, 중대뇌동맥 폐색 환자 1명, 외상후 증후군 1명, 뇌종양 1예를 대상으로 하여, 뇌의 routine 자기공명 영상과 함께 Gd-DTPA 0.1 mmol/kg를 급속 주사 후 자화율 대조 EPI 영상을 얻었다. 영상 기기는 Magnetom Vision(Siemens Medical Systems, Erlangen, Germany)이며, EPI 영상 지표들은 TR/TE는 0.8/29 msec, slice 두께 6 mm, slice 수 10, 화소수 128 $\times$ 128, FOV 215 $\times$ 215 mm, 영상획득 1 회, 1회 검사시간 1.32 초, 검사수 30 회로서, 총 검사시간은 40 초였다. 검사 후 영상처리(post processing)는 Magnetom Vision의 VB31D 자체 프로그램을 이용하였는데, 2-score를 이용한 관류영상은 조영제 유입전 영상들, 조영제 최대 유입기 영상들, 그리고 조영제 배출기 영상들 4-5 회를 각각 한 군으로 하여, Z-score 1.2에서 2.0 사이에서 여러번 반복하여 영상을 재구성하였다. 감산에 의한 역동영상은 조영제 도달 전의 영상으로부터 조영제 유입 후의 영상을 차례로 빼어서 영상을 재구성하였으며, 이들 영상을 재정리하여 각 단면의 시간 경과에 따른 관류 양상을 연속하여 관찰하였다 두 방법에 의한 영상 재구성은 각각 약 10분 정도가 소요되었다.