• Title/Summary/Keyword: protection layer

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Effectiveness of parylene coating on CdZnTe surface after optimal passivation

  • B. Park;Y. Kim;J. Seo;K. Kim
    • Nuclear Engineering and Technology
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    • v.54 no.12
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    • pp.4693-4697
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    • 2022
  • Parylene coating was adopted on CdZnTe (CZT) detector as a mechanical protection layer after wet passivation with hydrogen peroxide (H2O2) and ammonium fluoride (NH4F). Wet chemical passivant lose their effectiveness when exposed to the ambient conditions for a long time. Parylene coating could protect the effectiveness of passivation, by mechanically blocking the exposure to the ambient conditions. Stability of CZT detector was tested with the measurement of leakage current density and response to radio-isotopes. When the enough thickness of parylene (>100 ㎛) is adopted, parylene is a promising protection layer thereby ensuring the performance and long-term stability of CZT detectors.

A Development of a Framework for the Measuring National Information Security Level (국가정보보호수준 평가지표 개선 및 지수 산출에 관한 연구)

  • Lim, Gyoo Gun;Bae, Soon Han;Lee, Dae Chul;Ji, Sang-Ho;Baek, Seung Ik
    • Journal of Information Technology Services
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    • v.12 no.4
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    • pp.187-204
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    • 2013
  • In this study, we developed a comprehensive model to measure the National Information Security Level based on PRM framework. The proposed model reflected a rapidly changing technology environments such as social network service, mobile devices, and etc. This new model consists of three layers:Infrastructure Layer, the Action Layer and the Performance Layer, and there are 16 sub-indexes under the 3 layers. To develop new model and sub-indexes for measuring the National Information Security Level, much amounts of documents related to security indexes or deliberation criteria and security guidelines from international organization were reviewed and then most probable index pool were composed. The Index pool were verified by expert group consisting of professors and specialists. Through five times of screening and having an evaluation review, 16 sub-indexes were deduced and then Delphi and AHP have been conducted to obtain validity and objectiveness of the indexes. Thus the new proposed national information security index will show more exact national information security level and we expect that the indexes give much implications for establishing information protection policy.

Corrosion Resistance Evaluation of Aluminum Thermal Spray Coated AA5083-H321 (알루미늄 열용사 코팅된 AA5083-H321의 내식성 평가)

  • Il-Cho Park;Sungjun Kim;Min-Su Han
    • Corrosion Science and Technology
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    • v.22 no.2
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    • pp.108-114
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    • 2023
  • In this study, anti-corrosion effect was investigated through various electrochemical experiments after applying Al thermal spraying technology to AA5083-H321. Open circuit potential and anodic polarization curves were analyzed through electrochemical experiments in natural seawater. The shape of the surface was observed using a scanning electron microscope (SEM) and a 3D microscope before and after the experiment. Component and crystal structure were analyzed through EDS and XRD. As a result, the surface roughness of AA5083-H321 and the Al thermal sprayed coating layer increased due to surface damage caused by anodic dissolution reaction during the anodic polarization experiment. The corrosion rate of AA5083-H321 was relatively low because the Al thermal spray coating layer contained structural defects such as pores and crevices. Nevertheless, the open circuit potential of the Al thermal spray coating layer in natural seawater was measured about 0.2 V lower than that of AA5083-H321. Thus, a sacrificial anode protection effect can be expected.

Routing and Wavelength Assignment in Survivable WDM Networks without Wavelength Conversion

  • Lee, Tae-Han;Park, Sung-Soo;Lee, Kyung-Sik
    • Management Science and Financial Engineering
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    • v.11 no.2
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    • pp.85-103
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    • 2005
  • In this paper, we consider the routing and wavelength assignment problem in survivable WDM transport network without wavelength conversion. We assume the single-link failure and a path protection scheme in optical layer. When a physical network and a set of working paths are given, the problem is to select a link-disjoint protection path for each working path and assign a wavelength for each working and protection path. We give an integer programming formulation of the problem and propose an algorithm to solve it. Though the formulation has exponentially many variables, we solve the linear programming relaxation of it by using column generation technique. We devise a branch-and price algorithm to solve the column generation problem. After solving the linear programming relaxation, we apply a variable fixing procedure combined with the column generation to get an integral solution. We test the proposed algorithm on some randomly generated data and test results show that the algorithm gives very good solutions.

An Experimental Study to develope the Subsidence Equation for Riprap Protection around the Pier (교각에 설치된 사석보호공의 침하량 산정식 도출에 관한 실험 연구)

  • Ji, Un;Yeo, Woon Kwang;Lee, Won Min;Kang, Joon Gu
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.29 no.1B
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    • pp.63-71
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    • 2009
  • Riprap filter should be installed around the pier to prevent riprap subsidence due to sediment winnowing or leaching between the riprap and bed layers. However, riprap protection without filters is commonly applied in the field because of ambiguous specifications and technical and economical difficulties to install the filter layer. Therefore, the hydraulic experiments were conducted in this study to measure and analyze the riprap subsidence quantitatively with different conditions for thickness of riprap layer, approached velocity, sizes of riprap and bed material. As the velocity was increased and size of bed material and thickness of riprap layer were decreased, the subsidence was increased. Consequently, the dimensionless riprap subsidence equation was derived using the synthesized experimental results. The results of this study could be employed as a standard criterion or predictor to evaluate the subsidence stability.

The Organic-Inorganic Hybrid Encapsulation Layer of Aluminium Oxide and F-Alucone for Organic Light Emitting Diodes

  • Gwon, Deok-Hyeon;Seong, Myeong-Mo
    • Proceedings of the Korean Vacuum Society Conference
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    • 2012.08a
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    • pp.374-374
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    • 2012
  • Nowadays, Active Matrix Organic Light-Emitting Diodes (AM-OLEDs) are the superior display device due to their vivid full color, perfect video capability, light weight, low driving power, and potential flexibility. One of the advantages of AM-OLED over Liquid Crystal Display (LCD) lies in its flexibility. The potential flexibility of AM-OLED is not fully explored due to its sensitivity to moisture and oxygen which are readily present in atmosphere, and there are no flexible encapsulation layers available to protect these. Therefore, we come up with a new concept of Inorganic-Organic hybrid thin film as the encapsulation layer. Our Inorganic layer is Al2O3 and Organic layer is F-Alucone. We deposited these layers in vacuum state using Atomic Layer Deposition (ALD) and Molecular Layer Deposition (MLD) techniques. We found the results are comparable to commercial requirement of 10-6 g/m2 day for Water Vapor Transmission Rate (WVTR). Using ALD and MLD, we can control the exact thin film thickness and fabricate more dense films than chemical or physical vapor deposition methods. Moreover, this hybrid encapsulation layer potentially has both the flexibility of organic layers and superior protection properties of inorganic layer.

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Properties of Organic-Inorganic Protective Films on Flexible Plastic Substrates by Spray Coating Method (연성 플라스틱 기판위에 스프레이 코팅방법으로 제조한 유·무기 보호막의 특성)

  • Lee, Sang Hee;Chang, Ho Jung
    • Journal of the Microelectronics and Packaging Society
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    • v.24 no.4
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    • pp.79-84
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    • 2017
  • The solar cells should be protected from the moisture and oxygen in order to sustain the properties and reliability of the devices. In this research, we prepared the protection films on the flexible plastic substrates by spray coating method using organic-inorganic hybrid solutions. The protection characteristics were studied depending on the various process conditions (nozzle distance, thicknesses of the coatings, film structures). The organic-inorganic solutions for the protection film layer were synthesized by addition of $Al_2O_3$ ($P.S+Al_2O_3$) and $SiO_2$ ($P.S+SiO_2$) nano-powders into PVA (polyvinyl alcohol) and SA (sodium alginate) (P.S) organic solution. The optical transmittances of the protection film with the thicknesses of $5{\mu}m$ showed 91%. The optical transmittance decreased from 81.6% to 73.6% with the film thickness increased from $78{\mu}m$ to $178{\mu}m$. In addition, the protective films were prepared on the PEN (polyethylene naphthalate), PC (polycarbonate) single plastic substrates as well as the Acrylate film coated on PC substrate (Acrylate film/PC double layer), and $Al_2O_3$ film coated on PEN substrate ($Al_2O_3$ film/PEN double layer) using the $P.S+Al_2O_3$ organic-inorganic hybrid solutions. The optimum protection film structure was studied by means of the measurements of water vapor transmittance rate (WVTR) and surface morphology. The protective film on PEN/$Al_2O_3$ double layer substrate showed the best water protective property, indicating the WVTR value of $0.004gm/m^2-day$.

Effects of High Temperature Heat Treatment on the Microstructure and Superconducting Property of HTS Coated Conductor (Coated Conductor의 특성 및 미세조직에 미치는 고온열처리 영향)

  • Doh, Min-Ho;Hong, Gye-Won;Lee, Hee-Gyoun
    • Progress in Superconductivity
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    • v.11 no.1
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    • pp.1-7
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    • 2009
  • HTS coated conductor was heat treated at high temperatures below the melting points of silver and YBCO at different oxygen partial pressures. Current carrying capacity and microstructure were varied depending on the presence of silver protection layer. Critical current of coated conductor without silver protection layer was not changed when heat treatment was performed at $850^{\circ}C$ for 2 hr in an oxygen atmosphere. However, coated conductor with silver protection layer revealed abrupt drop of $I_c$ from 140A to 8A when heat treatment was performed at $800^{\circ}C$ for 2 hr in an oxygen atmosphere. Coated conductor with silver protection layer retained $70{\sim}80$ percent of its original $I_c$ when heat treatment was performed at $800^{\circ}C$ for 2 hr in an argon atmosphere containing 1000ppm oxygen. SEM and XRD observations showed the presence of interaction between YBCO and silver depending on the atmosphere of heat treatment. The reaction between YBCO superconductor and silver was accelerated at high oxygen partial pressure and resulted in the change in microstructure and decrease of critical current density even by the heat treatment performed at temperature much lower than the melting points of silver and YBCO.

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Implementation of a Network Provisioning System with User-driven and Trusty Protection Management

  • Lim, H.
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.9 no.11
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    • pp.4720-4738
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    • 2015
  • Proper management on user-driven virtual circuits (VCs) is essential for seamless operation of virtual networks. The Network Provisioning System (NPS) is useful software for creating user-driven VCs automatically and must take fault management into account for physical layer impairments on user-driven VCs. This paper addresses a user-driven and trusty protection management in an NPS with an open standard Network Service Interface (NSI), as a contribution to show how to implement the user-driven and trusty protection management required for user-driven VCs. In particular, it provides a RESTful web service Interface for Configuration and Event management (RICE) that enable management of a distinguished data and control plane VC status between Network Service Agents (NSAs) in the event of a node or link fault and repair in a domain. This capability represents a contribution to show how network and protection events in a domain can be monitored between NSAs (NPSs with the NSI) in multiple domains. The implemented NPS controls and manages both the primary and backup VC with disjoint path in a user-driven manner. A demonstration to verify RICE API's capability is addressed for the trusty protection in the dynamic VC network.

Selective Wetting Technique for Fabrication of Color Filters

  • Hong, Jong-Ho;Li, Hongmei;Na, Yu-Jin;Lee, Sin-Doo
    • 한국정보디스플레이학회:학술대회논문집
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    • 2009.10a
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    • pp.1386-1388
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    • 2009
  • We report on a new method of fabricating color filters based on selective wetting of color inks. The reversible formation of a hydrophobic layer provides sequential generation and protection of successive color filter patterns through a simple coating process. The transmittance and geometrical properties of the fabricated color filter were described.

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