• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.18 no.6
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• pp.107-112
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• 2018

Shielding effectiveness (SE) improvement with EMI shield layers fabricated by conformal spray coating system was studied. Silver or Nickel powder filled acrylic resin were sprayed on the samples. We compared the performance with the viscosity of 400 cPs and 100 cPs cases. The thickness range of the coating layer was 20 to 50 um for the silver, 60 to 120 um for the nickel. The shielding effectiveness was measured by ASTM D4935 using coaxial type TEM-cell. The silver-filled resin showed much better performance than that of the nickel-filled resin. The shielding effectiveness increased almost proportional to the thickness of the coating layers until being saturated around 63 dB for the silver-layer or around 34 dB for the nickel-layer. The best performance measured in this study was the shielding effectiveness of 63 dB with $35{\mu}m-thick$ of silver-layer.

• Restorative Dentistry and Endodontics
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• v.35 no.5
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• pp.368-373
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• 2010

Objectives: This study investigated the effect of infection control barrier thickness on power density, wavelength, and light diffusion of light curing units. Materials and Methods: Infection control barrier (Cleanwrap) in one-fold, two-fold, four-fold, and eightfold, and a halogen light curing unit (Optilux 360) and a light emitting diode (LED) light curing unit (Elipar FreeLight 2) were used in this study. Power density of light curing units with infection control barriers covering the fiberoptic bundle was measured with a hand held dental radiometer (Cure Rite). Wavelength of light curing units fixed on a custom made optical breadboard was measured with a portable spectroradiometer (CS-1000). Light diffusion of light curing units was photographed with DSLR (Nikon D70s) as above. Results: Power density decreased significantly as the layer thickness of the infection control barrier increased, except the one-fold and two-fold in halogen light curing unit. Especially, when the barrier was four-fold and more in the halogen light curing unit, the decrease of power density was more prominent. The wavelength of light curing units was not affected by the barriers and almost no change was detected in the peak wavelength. Light diffusion of LED light curing unit was not affected by barriers, however, halogen light curing unit showed decrease in light diffusion angle when the barrier was four-fold and statistically different decrease when the barrier was eight-fold (p < 0.05). Conclusions: It could be assumed that the infection control barriers should be used as two-fold rather than one-fold to prevent tearing of the barriers and subsequent cross contamination between the patients.

• Journal of the Korean GEO-environmental Society
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• v.15 no.1
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• pp.13-23
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• 2014

Geotechnical evaluation on the reactive drain pile which can achieve simultaneously both the soft ground improvement and the remediation of contaminated pore water in reclamation site was performed. Applicability of steel-making slag used as a inside reactive material was confirmed. To investigate the consolidation characteristics of the soft ground improved by reactive drain pile, testing devices to form and install the reactive drain pile were developed and laboratory tests were performed according to the existence of outside sand drain and the length of impermeable barrier. Test results showed that the consolidation time was decreased as the shortening of impermeable barrier. However, the effect of outside sand drain on consolidation time was dominant compared with the length of impermeable barrier.

• Journal of Korean Society of Disaster and Security
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• v.11 no.1
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• pp.1-5
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• 2018

Power plant is the important infrastructure to generate electricity. This plant in normally located next to river and seashore in order to take cooling water through intake. However, the plant is stopped when marine organism blocks the intake, and it caused damages by social and commercial. Therefore, air bubble barrier has been used to block marine organism in order to operate the plant properly. The aim of this study was to test the rates of cut off of floating substance by air bubble barrier to develop the facility for the plant. The test was conducted by current velocity, pressure of air, specific gravity of the substance and the layer of the barrier, and the result showed the blocking rates by the condition. It will be used as basic data to develop the air bubble barrier and to operate power plant properly from the marine organism.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.3
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• pp.575-580
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• 2015

Asymmetric double gate(DG) MOSFET is a novel transistor to be able to reduce the short channel effects. This paper has analyzed a off current for conduction path of asymmetric DGMOSFET. The conduction path is a average distance from top gate the movement of carrier in channel happens, and a factor to change for oxide thickness of asymmetric DGMOSFET to be able to fabricate differently top and bottom gate oxide thickness, and influenced on off current for top gate voltage. As the conduction path is obtained and off current is calculated for top gate voltage, it is analyzed how conduction path influences on off current with parameters of oxide thickness and channel length. The analytical potential distribution of series form is derived from Poisson's equation to obtain off current. As a result, off current is greatly changed for conduction path, and we know threshold voltage and subthreshold swing are changed for this reasons.

• Elastomers and Composites
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• v.46 no.2
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• pp.94-101
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• 2011

The conventional radiation barriers may show some disadvantages such as heavy weight and possibility of poisoning human bodies because they are composed of lead plates or resin plates containing large amounts of lead powders. Another disadvantage may be direct penetration of radiation through small pin holes. In this article, technologies of multi-layered polymer barriers against radiation, which has been extensively focused recently, will be introduced. A new concept of radiation protection as well as improving endurance with employing nano-layered inorganic particles is introduced.

• Restorative Dentistry and Endodontics
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• v.35 no.4
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• pp.235-237
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• 2010

When curing the composite restorations with light curing units, the light guides are often in direct contact with oral tissues, therefore contamination of light guides is inevitable. Curing light guides fall into the "semicritical" instrument category according to the Centers for Disease Control and Prevention (CDC) and must be heat or vapor-sterilized or at a minimum, these semicritical instruments must be sterilized in a liquid chemical agent. Currently, most common methods of maintaining sterility of the light guides are wiping the guide with a disinfectant, such as glutaraldehyde, after each patient use; using autoclavable guides; using presterilized, single-use plastic guides; and using translucent disposable barriers to cover the guide.

• Membrane Journal
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• v.33 no.6
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• pp.447-453
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• 2023

The performance of computer systems and the development of various computer simulation programs have made it possible to analyze chemical systems composed of more complex elements, and accordingly, research using molecular dynamics simulation is being actively conducted. Research on calculating the gas permeation characteristics of polymer membranes by molecular dynamics, which was previously conducted mainly through experiments, is receiving attention for gas barrier membranes used in food packaging and pharmaceuticals. Recently, there has been a report that a gas barrier effect appears when a coating film is made using silk fibroin, and in this study, a study was conducted using molecular dynamics simulation to confirm whether an oxygen barrier effect appears when a composite film is made using silk fibroin. We built a single model, calculated the gas permeation characteristics, and compared it with the experimental value to confirm that the model reflects the actual experimental results. Actual composite membrane models were then built and the gas movement path within the polymer was analyzed. As a result, oxygen molecules were found that they could not pass through and was blocked in the fibroin region. Therefore, the composite membrane with silk fibroin has excellent oxygen barrier property and is expected to be useful in food packaging, etc.

• Electrical & Electronic Materials
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• v.9 no.5
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• pp.490-497
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• 1996

RF마그네트론 스파터링에 의한 $sSnO_2$ 박막을 증착한 결과 작동조건에 따라 표면에서 막손상이 발생하였는데, 이는 target에서 생성된 높은 에너지의 고속입자가 기판에서 직접 충돌로 일어나며, 마그네트론의 자계분포와도 관계된다. 또한 기판의 위치에 따라 박막의 전기적, 구조적 특성이 급격히 변하는데 본 논문은 중심자석의 세기와 RF power, 가스압력, 그리고 기판온도 등의 스파터링 작동조건을 변화시키면서 박막의 비손상을 검토하였고, 물성특성을 평가하였다. 실험결과로 부터 기판의 외축부에서 제작된 박막은 전반적으로 막손상이 없었고, 특히 target의 중심자석을 Cobalt로 설치하고 15 mTorr의 가스압력과 50 W의 RF power로 한 경우 가장 우수한 특성을 가진 박막을 얻을 수 있었다. 추가로 막손상을 방지하고자, 환원형의 masking glass를 target위에 설치하였는데, 고에너지 입자의 직접 충돌을 확실히 차단할 수 있었으며, 비저항율도 target의 부식부위 (erosion)에 대응하는 부분에서 100배 정도로 개선하였다.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.487-487
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• 2012

플라즈마 디스플레이 패널(PDP)은 공정 절차가 간단하고 가격 경쟁력이 매우 뛰어나 일찌감치 대형 평판 디스플레이 시장을 주도해 왔으며 빠른 응답 속도를 기반으로 한 생생한 화질의 구현으로 3D TV 시장에서도 꾸준한 사랑을 받고 있다. 향후 더 큰 화면을 요구하는 PID(Public Information Display) 시장에서도 PDP 는 두각을 나타낼 수 있을 것으로 보인다. 하지만 PDP 는 여전히 LCD, OLED 등의 디스플레이에 비해 발광 효율이 낮고 소비 전력이 높다는 단점을 가지고 있다. 또한 미국 환경청(EPA)과 에너지부(DOE)가 공동으로 마련한 전자 제품의 효율 등급제인 에너지 스타(Energy Star) 제도가 끊임없이 개편되면서 소비 전력에 대한 규제가 점차 강화되고 있기 때문에 발광 효율 및 소비 전력 특성의 개선은 현재 PDP 업계가 해결해야 할 가장 중요한 과제라고 할 수 있다. 발광 효율의 개선과 관련하여 최근에는 PDP의 보호막으로 널리 쓰이고 있는 MgO 보다 2차 전자 방출 계수가 높아 PDP의 구동 전압을 낮추는 동시에 휘도와 발광 효율 특성을 개선시킬 수 있는 신 보호막에 대한 연구가 활발히 이루어지고 있다. MgO를 대체 가능한 신 보호막으로 언급되는 물질은 SrO 혹은 CaO 등이 대표적이다. 하지만 이러한 물질들은 공기 및 수분에 대한 용해도가 높기 때문에 증착된 막이 이후의 공정 과정(합착 및 가열 배기 등)에서 대기 중에 노출 될 경우 심하게 변질될 수 있다. 이러한 문제점을 해결하기 위해서 신 보호막 위에 기존의 MgO 보호막을 얇게 증착하여 공기로부터의 접촉을 차단하거나 펠렛을 제조하는 과정에서 MgO 에 신 보호막 물질을 소량만 첨가하는 등의 방법들이 제안되어 왔으며 그 결과 기존의 PDP 대비 구동 전압을 낮추고 발광 효율을 획기적으로 개선하는데 성공한 결과들이 지속적으로 보고되고 있다. 하지만 신 보호막이 공기 및 수분에 민감한 만큼, 고온의 공정으로 인해 PDP의 하판 유리로부터 상판에 증착된 박막으로 확산되는 불순물에 의해서도 오염되며 이 역시 신 보호막의 특성을 구현하는데 방해 요소로 작용한다. 본 연구에서는 PDP 하판의 불순물이 상판의 박막으로 확산되는 것을 방지하고자 하판 형광체 인쇄전 PECVD 증착법으로 확산 방지막을 1 가량 형성하였다. 이후 SIMS 분석을 통하여 하판 불순물의 확산이 효과적으로 차단됨을 확인하였고 신 보호막의 오염을 최소화하여 결과적으로 PDP의 구동 전압을 낮추고 효율을 획기적으로 개선하는데 기여할 수 있음을 확인하였다.