• Nuclear Engineering and Technology
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• 제52권8호
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• pp.1706-1713
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• 2020

Functionally gradient material (FGM) is promisingly effective in mitigating the thermal stress between plasma facing materials (PFM) and structural materials. However, the corresponding research with respect to W/V FGM has not been reported yet. In this work, we firstly report the successful fabrication of W/V FGM by a combined technology of mechanical alloying (MA) and spark plasma sintering (SPS). The microhardness and microstructure of the consolidated sample were both investigated. W/V stacks show significantly enhanced microhardness (>100%) compared with pure W plate, which is beneficial to the integral strength of the hybrid structure. Furthermore, we clarify that the different ductility of W and V should be carefully considered, otherwise W/V powder might aggregate and lead to the formation of compositional segregation, and simultaneously unmask the impact of V proportion on the distribution of second phase in W-V binary alloy system. This work provides an innovative approach for obtaining W-V connections with much better performance.

• Nuclear Engineering and Technology
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• 제51권1호
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• pp.190-197
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• 2019

W-K-TiC alloys with different titanium carbide concentrations (0.05, 0.1, 0.25, 0.5, 1, 2) wt.% were fabricated through Mechanical Alloying and Spark Plasma Sintering. The effects of the addition of nano-scaled TiC particles on the relative density, Vickers micro-hardness, microstructure, crystal information, thermal shock resistance, and tensile strength were investigated. It is revealed that the doped TiC nano-particles located at the grain boundaries. The relative density and Vickers micro-hardness of W-K-TiC alloys was enhanced with TiC addition and the highest Vickers micro-hardness is 731.55. As the TiC addition increased from 0.05 to 2 wt%, the room-temperature tensile strength raised from 141 to 353 MPa. The grain size of the W-K-TiC alloys decreased sharply from $2.56{\mu}m$ to 330 nm with the enhanced TiC doping. The resistance to thermal shock damage of W-K-TiC alloys was improved slightly with the increased TiC addition.

• 대한방사선기술학회지:방사선기술과학
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• 제44권6호
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• pp.591-597
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• 2021

In the present study, we developed virtual reality education contents for radiation generator on radiation education field. The radiation generator was divided by module and even the X-ray exposure part was manufactured in detail for designing 3D models. The mechanical details of the X-ray exposure part, the function of adjusting field size of the X-ray, the function of moving the exposure part, and the demonstrating the principle of the X-ray tube were applied. For developing VR contents, the Unreal Engine was used. To evaluate the usefulness of virtual reality content, we used t-test by SPSS. The group used the simulator showed significantly higher levels of understanding of X-ray generation, X-ray irradiation unit composition, irradiation field size adjustment, irradiation unit position adjustment, and overall composition and function. We believe that this VR contents will be used well with radiation safe environment.

• 대한방사선기술학회지:방사선기술과학
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• 제46권6호
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• pp.493-499
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• 2023

This study developed education contents of measuring spatial dose with virtual reality simulation and applied to students majoring radiological science. The virtual reality(VR) contents with measuring spatial dose rate in the radiation controlled area was developed based on the simulation from pilot study. In this simulation, the tube voltage and tube current can be set from 60 to 120 kVp in 10 kVp steps and 10 to 40 mAs in 10 mAs increments, and the distance from source can be set from 30 to 400 cm continuously. Iron and lead shields can be placed between the source and the detector, and shielding thickness can be set by 1 mm increments ranging from 1 to 20 mm. We surveyed to students for evaluating improvement of understanding spatial dose rate between before and after education by VR simulation. The survey was conducted with 5 questions(X-ray exposure factors, effects by distance from the source, effects from using shield, depending on material and thickness of shield, concept and measuring of spatial dose rate) and all answers showed significant improvement. Therefore, this VR simulation content will be well used in education for spatial dose rate and radiation safety environments.

• Journal of Nutrition and Health
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• 제43권1호
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• pp.57-68
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• 2010

Worksite health promotion programs have been associated with reductions in health risks but are labor-intensive and costly to implement. Therefore, innovative strategies to provide a cost-effective approach to health education program are needed. The purpose of this study was to investigate the effects of a worksite on-line health education program by email on metabolic syndrome risk factors and dietary intakes in male workers with metabolic syndrome. Anthropometric and biochemical parameters were measured and the nutrient intakes were assessed through FFQ. The diagnosis of metabolic syndrome was adapted from NCEP-ATP III with blood pressure, fasting blood glucose, triglyceride, HDL cholesterol, and Asia-Pacific definition with waist circumference. The education group consisted of 212 male workers and the non-education group of 236 age-matched male workers. The on-line health education program provided 10 sessions by e-mail. After a worksite on-line health education program, systolic blood pressure (p < 0.001), diastolic blood pressure (p < 0.001) and fasting blood glucose (p < 0.001) were significantly decreased and HDL cholesterol (p < 0.001) was significantly increased in the education group. Intakes of total energy (p < 0.05), carbohydrate (p < 0.05), sodium (p < 0.05) were significantly decreased in the education group, but there were no significant differences in dietary intakes in the non-education group after a worksite on-line health education program. The results indicate that online health education program by e-mail is effective for improving metabolic syndrome risk factors and dietary intakes in male workers and show potential for use in the working setting.

• Journal of Radiation Protection and Research
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• 제40권3호
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• pp.174-180
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• 2015

예비 방사선 작업 종사자인 방사선학과 대학생을 대상으로 방사선 기초 개념과 공간선량 인식, 방사선 안전 인식에 대해 알아보고자 하였다. X선 촬영 실습실에서 X선 조사 시 발생하는 공간선량을 학생들이 직접 측정함으로써 방사선 기초 개념과 공간선량 인식에 따른 실험 전 후의 방사선 안전 인식 변화를 파악하고자 하였다. 그 결과 실험 후에 학생들의 방사선 안전 인식이 보수적이고 엄격하게 변화하는 것을 알 수 있었다. 그럼에도 불구하고 방사선학과 대학생들의 경우 방사선 안전 인식 보다 직업의식이 앞서는 형태를 볼 수 있었는데 이는 의료적 이용에 따른 이득을 우선적으로 고려한 결과로 생각된다. 이에 따라 의료적 이익의 범위 내에서 방사선 이용에 따른 세분화된 안전교육 프로그램이 필요성이 요구된다. 따라서 시청각 자료를 이용한 단순한 강의 중심의 안전 교육이 아닌, 직접 공간선량 측정 실험과 같은 체험적 안전 교육 프로그램을 제안하는 바이며 방사선 안전 인식의 보수적인 관점과 엄격한 태도를 지향하는 직업의식 교육이 필요한 것으로 파악되었다.

• Asian Pacific Journal of Cancer Prevention
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• 제16권18호
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• pp.8155-8161
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• 2016

The prognostic significance of AgNOR proteins in stage II-III rectal cancers treated with chemoradiotherapy was evaluated. Silver staining was applied to the $3{\mu}m$ sections of parafin blocked tissues from 30 rectal cancer patients who received 5-FU based chemoradiotherapy from May 2003 to June 2006. The microscopic displays of the cells were transferred into the computer via a video camera. AgNOR area (nucleolus organizer region area) and nucleus area values were determined as a nucleolus organizer regions area/total nucleus area (NORa/TNa). The mean NORa/TNa value was found to be $9.02{\pm}3.68$. The overall survival and disease free survival in the high NORa/TNa (>9.02) patients were 52.2 months and 39.4 months respectively, as compared to 100.7 months and 98.4 months in the low NORa/TNa (<9.02) cases. (p<0.001 and p<0.001 respectively). In addition, the prognosis in the high NORa/TNa patients was worse than low NORa/TNa patients (p<0.05). In terms of overall survival and disease-free survival, a statistically significant negative correlation was found with the value of NORa/TNa in the correlations tests. Cox regression analyses demostrated that overall survival and disease-free survival were associated with lymph node status (negative or positive) and the NORa/TNa value. We suggest that two-dimensional AgNOR evaluation may be a safe and usable parameter for prognosis and an indicator of cell proliferation instead of AgNOR dots.

• 융합정보논문지
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• 제12권4호
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• pp.205-211
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• 2022

우리 인간의 주변에는 다양한 방사성 물질이 존재하고 있다. 최근 들어서는 삶의 질 향상과 함께 건강에 대한 관심도 높아지면서 방사선을 활용한 검사 등 또한 많아지고 있다. 본 연구에서는 이런 방사선을 생활 관련 방사선으로 정의하고, 이에 대한 지식을 측정할 수 있는 측정도구를 개발해 보았다. 그 결과 신뢰성이 확보되는 18개 문항을 개발하였다. 나아가 이를 이용하여 생활방사선 안전 관련 지식에 대한 실태를 분석해 보았다. 그 결과 방사선 관련 교육을 받은 그룹이 그렇지 않은 그룹에 비하여 통계적으로 유의하게 높은 점수를 받는 것으로 나타났다. 그리고 상관분석 및 회귀분석을 통해서 보았을 때 평소 안전 관련 관심도가 높을수록 생활방사선 안전 관련 지식이 높은 것으로 분석되었다. 이를 토대로 현대인들의 안전을 위하여 학교 교육과정에서 방사선 안전 관련 교수-학습이 이루어져할 필요성이 제안되었다.

• The Korean Journal of Ecology
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• 제8권2호
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• pp.99-107
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• 1985

Photosynthetically Active Radiation (PAR) affects the growth of plants as well as their photosynthetic rates. A mathematical model for intercepted solar radiation on the tilted leaf with any azimuth angle was established and the leaf orientation in which receives the maximum solar radiation was determined each month, during the growing season, and for an year. PAR was maximized at the leaf elevation of 50。~60。 in the winter, at that of 20。~40。. On the whole the leaves of tilt angle 0。~40。 received much radiation comparing with those of other tilt angles. The theoretical tendencies were compared with the distribution of leaf orientation measused practically. The average leaf elevation of maple tree was 17.0。$\pm$12.0。, and that of ginkgo was 29.8。$\pm$16.0。. Several results from other literatures support our suggestion that cumulative effevct of the relationships between surface normal vector and a vector pointing in the direction of the radiation determine the leaf orientation.

• The Journal of the Acoustical Society of Korea
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• 제28권2E호
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• pp.51-59
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• 2009

Mutual radiation impedance becomes more important in the design and analysis of acoustic transducers for higher power, better beam pattern, and wider bandwidth at low frequency sonar systems. This review paper focused on literature survey about the researches of mutual radiation impedance in the acoustic transducer arrays over 60 years. The papers of mutual radiation impedance were summarized in terms of transducer array structures on various baffle geometries such as planar, cylindrical, spherical, conformal, spheroidal, and elliptic cylindrical arrays. Then the computation schemes of solving conventional quadruple integral in the definition of mutual radiation impedance were surveyed including spatial convolution method, which reduces the quadruple integral to a double integral for efficient computation.