• Journal of Korean Academy of Nursing
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• v.25 no.4
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• pp.668-680
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• 1995

The purpose of this study was to contribute to family nursing for reducing stress and improving coping of the parents of mentally retarded children. Data were collected through self-reported questionnaires during a period of 2 months between November 1994 and January 1995 in the Kyoung-in area. The subjects consist of 180 parents (90 mothers and 90 fathers) of mentally retarded children attending schools for the handicapped and 186 parents (93 mothers and 93 fathers) of normal children. The levels of general stress and of parental role stress were measured with the General stress scale and the Parental role stress scale, respectively, while the Coping scale was adopted to measure the level of coping. The data were analyzed by using Chi-square test. fisher's exact test, Repeated masured ANOVA, oneway ANOVA and Scheffe comparison test. The results were as follows ; 1. The level of general stress was significantly higher in the mothers and the fathers of the men-tally retarded than in the respective parents of the normal. Of the parents, the mothers experienced significantly greater level of general stress than the fathers did in both groups of the retarded and of the normal. 2. As for the parental role stress, the mothers and the fathers of the mentally retarded experienced significantly greater stress than respective parents of normal children did. In particular, the stress was significantly higher in the mothers than the fathers of these children in both groups. The difference in the levels of parental role stress experienced by mothers and by fathers was significantly bigger among those of the mentally retarded tnan among those of normal children. 3. No significant difference in the level of coping was observed between the mothers of both groups and the fathers of both groups. By contrast, the fathers revealed significantly greater scores in coping than the mothers in both groups. 4. General stress experienced by the fathers of the mentally retarded was different by health status, satisfaction with spouses, and the supports from their spouses. Health status, satisfaction with spouses, and monthly income Influenced parental role stress experienced by those fathers. Their level of coping was associated with their satis-faction with spouses and family life. 5. Of the mothers of the mentally retarded, the level of general stress was different by their health status, while parental role stress was related to the satisfaction with their spouses and the child's age. The level of coping among the mothers was different by the supports from their spouses. The above findings indicate that those parents of the mentally retarded did not take more coping strategies than those of the normal did, despite greater stress experienced among themselves. Hence, nursing intervention for managing stress should be given to those parents including fathers of mentally retarded children. Mothers of the mentally retarded, in particular, should receive high priority in planning nursing care, since they experience greater levels of both general stress and parental role stress than their spouses, which is most likey due to primary responsibility in child rearing given to them at home.

• Nuclear Engineering and Technology
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• v.52 no.3
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• pp.469-476
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• 2020

Research reactors in-core experimental facilities are designed to provide the highest steady state flux for user's irradiation requirements. However, fuel conversion from highly enriched uranium (HEU) to low enriched uranium (LEU) driven by the ongoing effort to diminish proliferation risk, will impact reactor physics parameters. Preserving the reactor capability to produce the needed flux to perform its intended research functions, determines the conversion feasibility. This study investigates the neutron flux in the central experimental facility of two material test reactors (MTR), the IAEA generic10 MW benchmark reactor and the 22 MW s Egyptian Test and Research Reactor (ETRR-2). A 3D full core model with three uranium enrichment of 93%, 45%, and 20% was constructed utilizing the OpenMC particle transport Monte Carlo code. Neutronics calculations were performed for fresh fuel, the beginning of life cycle (BOL) and end of life cycle (EOL) for each of the three enrichments for both the IAEA 10 MW generic reactor and core 1/98 of the ETRR-2 reactor. Criticality calculations of the effective multiplication factor (K_eff) were executed for each of the twelve cases; results show a reasonable agreement with published benchmark values for both reactors. The thermal, epithermal and fast neutron fluxes were tallied across the core, utilizing the mesh tally capability of the code and are presented here. The axial flux in the central experimental facility was tallied at 1 cm intervals, for each of the cases; results for IAEA 10 MW show a maximum reduction of 14.32% in the thermal flux of LEU to that of the HEU, at EOL. The reduction of the thermal flux for fresh fuel was between 5.81% and 9.62%, with an average drop of 8.1%. At the BOL the thermal flux showed a larger reduction range of 6.92%-13.58% with an average drop of 10.73%. Furthermore, the fission reaction rate was calculated, results showed an increase in the peak fission rate of the LEU case compared to the HEU case. Results for the ETRR-2 reactor show an average increase of 62.31% in the thermal flux of LEU to that of the HEU due to the effect of spectrum hardening. The fission rate density increased with enrichment, resulting in 34% maximum increase in the HEU case compared to the LEU case at the assemblies surrounding the flux trap.

• Radiation Oncology Journal
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• v.28 no.4
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• pp.224-230
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• 2010

Purpose: We designed the aft-multiple-slit (AMS) system to reduce scatter in cone-beam computed tomography (CBCT). As a preliminary study, we performed a Monte Carlo N-Particle Transport Code (MCNP) simulation to verify the effectiveness of this system. Materials and Methods: The MCNPX code was used to build the AMS geometry. An AMS is an equi-angled arc to consider beam divergence. The scatter-reduced projection images were compared with the primary images only and the primary plus scatter radiation images with and without AMS to evaluate the effectiveness of scatter reduction. To obtain the full 2 dimensional (2D) projection image, the whole AMS system was moved to obtain closed septa of the AMS after the first image acquisition. Results: The primary radiation with and without AMS is identical to all the slit widths, but the profiles of the primary plus scattered radiation varied according to the slit widths in the 2D projection image. The average scatter reduction factors were 29%, 15%, 9%, and 8% when the slit widths were 5 mm, 10 mm, 15 mm, and 20 mm, respectively. Conclusion: We have evaluated the scatter reduction effect of the AMS in CBCT imaging using the Monte Carlo (MC) simulations. A preliminary study based on the MCNP simulations showed a mount of scatter reduction with the proposed system.

• Progress in Medical Physics
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• v.15 no.4
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• pp.215-219
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• 2004

Due to their excellence for the high-energy therapy range of photon beams, researchers show increasing interest in applying MOSFET dosimeters to low- and medium-energy applications. In this energy range, however, MOSFET dosimeter is complicated by the fact that the interaction probability of photons shows significant dependence on the atomic number, Z, due to photoelectric effect. The objective of this study is to develop a very detailed 3-dimensional Monte Carlo simulation model of a MOSFET dosimeter for radiological characterizations and calibrations. The sensitive volume of the High-Sensitivity MOSFET dosimeter is very thin (1 ${\mu}{\textrm}{m}$) and the standard MCNP tallies do not accurately determine absorbed dose to the sensitive volume. Therefore, we need to score the energy deposition directly from electrons. The developed model was then used to study various radiological characteristics of the MOSFET dosimeter. the energy dependence was quantified for the energy range 15 keV to 6 MeV; finding maximum dependence of 6.6 at about 40 keV. A commercial computer code, Sabrina, was used to read the particle track information from an MCNP simulation and count the tracks of simulated electrons. The MOSFET dosimeter estimated the calibration factor by 1.16 when the dosimeter was at 15 cm depth in tissue phantom for 662 keV incident photons. Our results showed that the MOSFET dosimeter estimated by 1.11 for 1.25 MeV photons for the same condition.

• Journal of the Korean Society of Radiology
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• v.10 no.3
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• pp.153-159
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• 2016

This study investigated relationship between secondary electrons produced from single gold nanoparticle as a result of its interaction with radiation and particle size and incidence energy, provided basic data related to the dose enhancement effect based on gold nanoparticles. Monte Carlo simulation was applied by using MCNPX MC code, 50, 100, 150 kV and 6, 15 MV x-ray energy was used. In a water phantom, single gold nanoparticles that are 30, 50, 70, 90, and 110 nm in diameter were placed and the tally volume was designated at every 10 nm. Difference in electrons produced from gold nanoparticles was normalized based on absence of nanoparticle. When the X ray energy decreased and the diameter of gold particles increased, more electrons were produced. When the energy was lower, in the linear formula related to nanoparticle size and electron production, the gradient was higher. And, in comparison to the MV X-ray, at kV X-ray, significantly more electrons were produced. This study can be used as data to understand the dose enhancement effect based on gold nanoparticles, and further research related to various materials that dose enhancement including gold nanoparticles needs to be conducted.