• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.18 no.4
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• pp.79-83
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• 2018

An accurate method to measure shielding effectiveness(SE) of EMI spray coating film is presented. After high frequency simulating, Circular coaxial standard test fixture is fabricated. A sample of EMI spray coating film was fabricated for insertion into a circular coaxial standard test fixture. The measuring instrument used an Agilent 8722ES vector network analyzer for the SE measurement. The exact SE of copper and silver mixed spray coating sample was measured by the composition of the measuring instrument and the measuring sample. The SE of copper sample was measured at 70 dB and the SE of copper and silver mixed spray coating sample was measured at 60 dB. As a result of the measurement, the reliability of the circular coaxial standard test fixture was confirmed.

• Applied Chemistry for Engineering
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• v.25 no.6
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• pp.613-618
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• 2014

In this study, nitrogen doped graphene oxide (GO) was prepared using liquid phase ammonia treatment to improve its electrical properties. Also, the aminated GO was manufactured into a film format and the electromagnetic interference (EMI) shielding efficiency was measured to evaluate its electrical properties. The XPS result showed that the increase of liquid phase ammonia treatment concentration led to the increased nitrogen functional group on the GO surface. The measurement of EMI shielding efficiency reveals that EMI shielding efficiency of the liquid phase ammonia treated GO was better than that of non-treated GO. When GO was treated using the ammonia solution of 21% concentration, the EMI shielding efficiency increased by -5 dB at higher than 2950 MHz. These results were maybe due to the fact that nitrogen functional groups on GO help to improve the absorbance of electromagnetic waves via facile electron transfer.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.19 no.4
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• pp.35-39
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• 2019

The shielding effectiveness (SE) of the EMI spray coating film was measured in a three-dimensional structure. The shielding effectiveness was measured by AST D4935 using coaxial type TEM cell. A standard sample of the cylindrical slab is fabricated to measure the shielding effectiveness using the ASTM D4935. At this time, spray coating was performed by bonding a three-dimensional structure with NAND flash memory to a standard sample. In the case of spray coating, it was uniformly coated not only on the horizontal plane but also on the vertical plane of the three-dimensional structure. As a result of measurement, shielding effectiveness of maximum 59 dB was measured in a three-dimensional structure similar to the case without three-dimensional structure. As a result, it was confirmed that the spray coating can be uniformed even in the three-dimensional structure.

• Journal of Electrical Engineering and Technology
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• v.13 no.2
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• pp.936-942
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• 2018

The diagnostic multi-leaf collimator preventing unnecessary dose from entering into patients during the diagnostic examination was made in this study. The movement of the entire 50 leaves was embodied with the group of 25 ones thereof configured in a pair facing each other on the left and right of the median line. Dimensions of the length, width, and height of each shielding leaf were $5{\times}0.5{\times}0.5cm^3$ resulting in the maximum boost field of $10{\times}10cm^2$. The material of multi-leaf collimator had the excellence on the machinability with the use of the SKD-11 alloy tool steel having the high wear resistance against frequent movement, and it was devised to control both-side's shielding leaves by moving 2 motors unlike existing remedial multi-leaf collimator that use as many motors as the number of 50 shielding leaves. Thereafter, the transmission dose of leaves, cross-leaf leakage dose, and inter-leaf leakage dose were measured by the developed multi-leaf collimator attached to X-ray equipment. An ionization chamber was used to detect doses there from, and the comparative analysis was carried out by means of the radiographic film that was easy to detect the dose leakage in between each leaf. Results obtained from the test conducted in comparative analysis yielded approximately 98%, 96%, and 94% of shielding efficiency realized at each level of energy of 80kV, 100kV, and 120kV it was confirmed there was no dose leakage resulted from the varied level of irradiation energy. Thus the multi-leaf collimator to be developed based on this study is thought that it could fully reduce the unnecessary dose to patients in the diagnostic test and the shielding efficiency thereof is expected to be increasing if it is made in a miniaturized form with a way of increasing the thickness of each leaf later for an extended application to general diagnostic purposes.

• Journal of Adhesion and Interface
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• v.18 no.2
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• pp.59-67
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• 2017

Recently, integration of parts is accelerating according to the growth of the smart mobile industry. The integration of these parts causes problems of interference phenomena between the parts, and the importance of electromagnetic wave shielding technology to solve this problem is highlighted. Electromagnetic wave shielding technology is implemented so as to reflect or absorb electromagnetic waves, and generally conductive materials are utilized for electromagnetic wave shielding. Transparent shielding technology is required according to recent industrial changes. In this research, we propose transparent the shielding film using imprint technology with conductive composite binder. Utilizing UV polymerized acrylic binder to produce a conductive composite binder. Spherical, plate and stacked silver particles were used for conductivity. The changes of the curing characteristics, conductivity and adhesion were observed according to the structural characteristics of the silver particles. The use of spherical particles was the most efficient in the curing process, and an additional curing system was required to complement the UV-shadowing structure. In the conductivity evaluation, the stacked structure showed excellent characteristics. The adhesion of spherical system was the best. It is evaluated as a result of irregularities on the surface. Ultimately, the patterned film using this showed excellent transparency characteristics.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2013.05a
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• pp.58-58
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• 2013

폴리에스테르 필름상에 무전해 Cu 도금 및 무전해 Ni-P 도금층을 형성하는 방법으로 박형 전자파 차폐 필름의 제조에 대하여 연구 하였다. 무전해 도금의 전처리 방법으로 기존의 Pd 촉매를 사용하는 대신에, 증착법에 의한 Sn 피막의 형성으로 전자파 차폐 특성 및 유연성이 우수한 박형 전자파 차폐 필름의 형성이 가능하게 되었다.

• Electrical & Electronic Materials
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• v.10 no.7
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• pp.713-718
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• 1997

Polyaniline free standing films cast from N-methyl-2-pyrrolidinone(NMP) solution, camphorsulfonic acid(HCSA), dodecylbenzensulfonic acid(HDBSA), inorganic matter(carbon black, graphite) and metal(silver) were prepared by processings. The properties of these films such as crystallinity, near-infrared absorption spectra and conductivity were investigated. The HCSA and HDBSA doped polyaniline films cast from m-cresol and chloroform solvents showed the metallic property and high crystallinity, respectively. The value of conductivity in the HCSA doped polyaniline film obtained 180 S/cm. We have obtained the value of conductivity 200 S/cm in the metal(silver) doped polyaniline film, which is higher than that of the HCSA doped polyaniline film. The metal(silver) doped polyaniline film shows good properties as a electromagnetic shielding material.

• Korean Journal of Materials Research
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• v.8 no.5
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• pp.444-449
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• 1998

There are various shielding materials that have been considered; the use of a metallic plate or the layering of a conductive material on a plastic surface and the insertion of filler in plastics. All of these methods have shown their merits and weakness. Therefore, many studies have concentrated on developing materials that effectively cut down EMI without increase in weights of housing materials. In these respects, this study has focused on investigations of the shielding effect of materials that have electroless nickel plating on the lamella structured micro particles surface with low specific gravity. When a film of electroless nickel were plated on a micro particle surfaces and then mixed with paint, the electromagnetic shielding effects were measured as 63dB. Although these effects were less than that 90dB of the copper plate, trials in a series of 6 times increased the shielding effect by IOdB and is applicable to wide range of EMI shielding.

• Korean Journal of Materials Research
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• v.9 no.11
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• pp.1055-1061
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• 1999

Indium Tin Oxide (ITO) films were fabricated by vacuum deposition technique and their microwave shielding properties were investigated for the application to the transparent shield material. The vacuum coating was conducted in a RF co-sputtering machine. The film composition and structure associated with the sputtering conditions (argon and oxygen pressure. substrate temperature. RF input power) were investigated for the attainment of high electrical conductivity and good transparency. The electrical conductivity of IT0 films fabricated under the optimum deposition conditions (substrate temperature : $300^{\circ}C$. Ar flow rate : 20 sccm, Oxygen flow rate : 10 sccm, In/Sn input power : 50/30 W) showed 5.6$\times10^4$mho/m. The optical transparency is also considerably good. The microwave shielding properties including the dominant shielding mechanism are investigated from the electrical conductivity, thickness and skin depth of the ITO films. The total shielding effectiveness is then estimated to be 26 dB, which provides a suggestion that the IT0 films can be effectively used as the transparent shield material.

• The Research Journal of the Costume Culture
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• v.30 no.4
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• pp.579-593
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• 2022

This study examines the surface characteristics, electrical conductivity, electromagnetic wave blocking characteristics, infrared (IR) transmittance, stealth function, thermal characteristics, and moisture characteristics of IR thermal imaging cameras. Nylon film (NFi), nylon fabric (NFa), and 5 types of nylon mesh were selected as the base materials for aluminum sputtering, and aluminum sputtering was performed to study IR thermal imaging, color difference, temperature change, and so on, and the relationship with infrared transmittance was assessed. The electrical conductivity was measured and the aluminum-sputtered nylon film demonstrated 25.6kΩ of surface resistance and high electrical conductivity. In addition, the electromagnetic wave shielding characteristics of the sputtering-treated nylon film samples were noticeably increased as a result of aluminum sputtering treatment as measured by the electromagnetic wave blocking characteristics. When NFi and NFa samples with single-sided sputtering were placed on the human body (sputtering layer faced the outside air) and imaged using IR thermographic cameras, the sputtering layer displayed a color similar to the surroundings, showing a stealth effect. Moreover, the tighter the sample density, the better the stealth function. According to the L, a, b measurements, when the sputtering layer of NFi and NFa samples faced the outside air, the value of a was generally high, thereby demonstrating a concealing effect, and the △E value was also high at 124.2 and 93.9, revealing a significant difference between the treated and untreated samples. This research may be applicable to various fields, such as the military wear, conductive sensors, electromagnetic wave shielding film, and others.