• 조명전기설비학회논문지
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• 제28권11호
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• pp.1-8
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• 2014

Recently, damages resulting from light trespass that affects the human body (sleep) as one of light pollution control elements of outdoor Luminaires equipment are leading to continuous civil complaints and disputes and this is gradually expanding into a social problem. Accordingly, this study considers the need to develop a shielding plate in consideration of light distribution performance as an efficient measure to cope with damages from light trespass. Therefore, this study developed a shielding plate for LED Luminaires with a fine view that maximally inhibited light toward the backlight area compared to existing shielding plates and verified its performance.

• Nuclear Engineering and Technology
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• 제52권10호
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• pp.2387-2393
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• 2020

In this study, a gradient material for shielding neutrons and gamma rays was developed, which consists of epoxy resin, boron carbide (B₄C), lead (Pb) and a little graphene oxide. It aims light weight and compact, which will be applied on the transportable nuclear reactor. The material is made up of sixteen layers, and the thickness and components of each layer were designed by genetic algorithm (GA) combined with Monte Carlo N Particle Transport (MCNP). In the experiment, the viscosities of the epoxy at different temperatures were tested, and the settlement regularity of Pb particles and B₄C particles in the epoxy was simulated by matlab software. The material was manufactured at 25 ℃, the Pb C and O elements of which were also tested, and the result was compared with the outcome of the simulation. Finally, the material's shielding performance was simulated by MCNP and compared with the uniformity material's. The result shows that the shielding performance of gradient material is more effective than that of the uniformity material, and the difference is most noticeable when the materials are 30 cm thick.

• 대한방사선기술학회지:방사선기술과학
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• 제42권5호
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• pp.373-377
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• 2019

Radiation exposure is on the rise as the working hours of radiation workers increase. Accordingly, the importance of protection products for decreasing the dose of exposure has risen, and excellent X-ray shielding ability and light weight are required. The purpose of this study is to compare the Pb which use currently and other elements in order to reduce the exposure of workers to the most effective protection products. For experiment, we used the general X-ray equipment and angiography equipment, and obtained the Pb and apron's shielding rate. When the shielding rate of Pb and apron was compared in general X-ray equipment, the shielding rate was 95.1% for Pb 0.5 mm, 96.1% for apron 0.5 mmPb and 95.6% for Bi+W 0.5 mmPb. When compared the shielding rate of each aprons in angiography equipment, 0.5 mmPb apron was the highest as 96.4% and Bi+W 0.25 mmPb apron was the lowest as 90.2% at the 50 cm distance. The shielding rate of 0.5 mmPb apron was the highest as 95.7% and Bi+W 0.25 mmPb apron was the lowest as 85.9% at the 100 cm distance. As a result of evaluating the apron efficiency through this study, 0.5 mmPb apron showed the best shielding rate, but it was the heaviest apron. 0.35 mmPb apron and Bi+W 0.25 mmPb apron weighed light but had low shielding rate. Through the results of this experiment, it is recommended that radiation workers reduce radiation exposure by using more efficient protection products.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2000년도 추계학술대회 논문집
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• pp.306-309
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• 2000

The conductive polymers, polyaniline (PANI) emeraldine base and 3, 4-polyethylene dioxythiophene (PEDOT) were synthesized and coated on the PET film primer-dealt with acryl type to find out the electromagnetic shielding effectiveness. When conductive polymer such as PANI and PEDOT is used, if the thickness of coating increases then the electromagnetic shielding effectiveness increases, too, but the visible light transmittance decreases. For PANI, when its conductivity increased, its electromagnetic shielding effectiveness increased, too. For PANI, if the surface resistance is about 140 $\Omega$/$\square$, the shielding effectiveness is about 11 dB in the far field, and about 13 dB in the near field at 1 GHz. For PEDOT, when the surface resistance is about 200 $\Omega$/$\square$, the shielding effectiveness is about 3 dB.

• 한국방사선학회논문지
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• 제15권7호
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• pp.949-956
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• 2021

본 연구의 목적은 전자빔 치료에서 산란선을 차폐하는 데 사용되는 납의 단점을 극복하기 위한 대체 재료로 텅스텐 나노입자를 선택하여 고선량에서 발생하는 산란선에 차폐 효과가 있는지 여부를 평가하는 것이다. 선량계의 위치와 조사야의 크기를 일정하게 설정하기 위해 판을 자체 제작하였다. 유리 선량계는 10 × 10 cm² 크기의 조사야의 중앙에서 십자로 1, 2, 4 cm 떨어진 지점에 위치하여 12곳의 지점에 위치시켰다. 10 × 10 cm² 크기의 텅스텐 나노입자 차폐체를 0.4, 0.75, 1 mm의 소재로 두께 0.75 mm에서 최대 두께 4.0 mm의 총 12가지 유형의 차폐가 적용되었다. 선형가속기를 사용해서 6 MeV에서 4회, 12 MeV에서 4회 측정하였고 선량의 세기는 100 MU로 조사하였다. 실험 결과 조사야로부터 1 cm 거리에서 4 mm 차폐판이 가장 높은 차폐 효과를 보였다. 조사야로부터 2 cm 거리에 적용된 1 mm 차폐판이 차폐 효과가 가장 낮았다. 텅스텐 차폐판의 두께가 두꺼워짐에 따라 전자선 차폐 효과는 급격히 증가하였다. 결론적으로 텅스텐 나노입자는 전자빔 치료에서 납의 대체 재료로 사용이 가능함을 확인하였다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2003년도 추계학술대회 논문집(III)
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• pp.547-551
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• 2003

This paper presents the magnetic fields shielding properties of the light rail transit which are produced by the ripple-shaped currents in the power lines. To analyze these properties, the equivalent circuit model of the DC power supply system at the light rail transit system was induced by MATLAB-SIMULINK, and with the calculated results of the ripple-shaped currents, the magnetic fields shielding properties of the light rail transit were analyzed. The results are as follows. First The frequency of the ripple-shaped currents is 200[Hz] and its magnitude is 1.5[A]. Second the magnetic fields produced by the ripple-shaped currents of the DC power supply systems are well shielded by the aluminum made body of the light rail transit.

• 대한한의진단학회지
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• 제17권3호
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• pp.225-232
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• 2013

Objectives The aim of this study is to design a part in contact with the face of computerized tongue diagnosis system (CTDS), so that external light is effectively shielded even if the facial appearance and degree of protrusion differ when a patient opens or closes his/her jaws. Methods Each of the 4 researchers manually produced clay models of the part in contact with the face of CTDS. Shielding and contact feeling of the clay models were evaluated by 20 assessors. Based on the evaluation, we selected the appropriate model and produced the final silicon model. Then we evaluated the performance of the shielding of the completed silicon model. We took tongue pictures of 60 participants with a CTDS applying the silicon model in condition with external light and without it. The color values in RGB color model and gray scale of the tongue pictures in condition with external light were compared with those without external light. Results There was no significant difference between the color values of the picture taken in condition with external light and those without external light. Conclusions We concluded that the produced part in contact with the face of CTDS can effectively block out the external light.

• Nuclear Engineering and Technology
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• 제52권1호
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• pp.178-184
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• 2020

The traditional methods for radiation shield design always only focus on either the structure or the components of the shields rather than both of them at the same time, which largely affects the shielding performance of the facilities, so in this paper, a novel method for designing the structure and components of shields simultaneously is put forward to enhance the shielding ability. The method is developed by using the genetic algorithm (GA) and the MCNP software. In the research, six types of shielding materials with different combinations of elements such as polyethylene (PE), lead (Pb) and Boron compounds are applied to the radiation shield design, and the performance of each material is analyzed and compared. Then two typical materials are selected based on the experiment result of the six samples, which are later verified by the Compact Accelerator Neutron Source (CANS) facility. By using this method, the optimal result can be reached rapidly, and since the design progress is semi-automatic for most procedures are completed by computer, the method saves time and improves accuracy.

• 한국전기전자재료학회논문지
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• 제32권4호
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• pp.287-295
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• 2019

Privacy films are typically manufactured by combining black resin and transparent louver-shaped patterns. The use of black resin results in excellent light-shielding. However, black resin can reduce the transmittance of privacy films at the front viewing angle. In this study, we applied $SiO_2/SiON$ multi-layer thin films on a privacy film to maintain transmittance at the front viewing angle and improve light-shielding at the side viewing angle. We determined the optimum combination of thicknesses of the $SiO_2/SiON$ multi-layer stacks to increase the overall transmittance; the light shielding could be maximized at the side viewing angle.

• 펄프종이기술
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• 제38권4호
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• pp.68-75
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• 2006

Electromagnetic shielding sheet using the carbon and wood fiber mixture was manufactured in an effort to develop an electromagnetic shielding packaging material. Carbon fibers were cut into 5, 10, and 15 mm using the automatic cutting device and blown and dispersed using compression air passed through the fine nozzle. Then carbon fibers were slurried with water (0.1% consistency), and softwood kraft pulp along with cone starch were added. The wet mats were manufactured by dewatering in modified hand-sheet machine. The wet mats were pressed upto $4kgf/cm^2$ in the carbon and wood fiber mixture mat press. The wet mats were dried in the automatic controlled plate dryer. Investigation on the formation and surface structure of the newly developed carbon and wood fiber mixture electromagnetic shielding sheet were carried out using the scanning electron microscopy and the image analyzer. Finally electromagnetic shielding characteristics of the newly developed carbon and wood mixture sheet were measured using net-work analyser. The result was promising in the light of the fact that this method could open a new way to substitute the expensive imported electromagnetic shielding sheet.