• Title/Summary/Keyword: printed density

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Evaluation of Thermal Conductivity for Screen-Printed AlN Layer on Al Substrate in Thickness Direction (알루미늄 기판에 스크린 인쇄한 AlN 후막의 두께 방향으로 열전도도 평가)

  • Kim, Jong-Gu;Park, Hong-Seok;Kim, Hyun;Hahn, Byung-Dong;Cho, Young-Rae
    • Journal of the Microelectronics and Packaging Society
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    • v.22 no.4
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    • pp.65-70
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    • 2015
  • A study on thermal properties for a single-layer metal and two-layer composites was investigated for the heat-sink application. For the single-layer metal, an aluminum alloy (Al6061) was selected. A screen printed aluminum nitride (AlN) layer on the Al6061 substrate was chosen for the two-layer composites. The thermal conductivity of the sample was determined from the thermal diffusivity measured by the light flash analysis (LFA), specific heat and density. Measured thermal property values were compared to calculated values using the data from the references. The thermal conductivity of composites with screen printed AlN layer on the Al6061 substrate decreased linearly with increasing the thickness of AlN layer. Measured values of the thermal conductivity for composites with $53{\mu}m$ and $163{\mu}m$ thick AlN layers were $114.1W/m{\cdot}K$ and $72.3W/m{\cdot}K$, respectively. In particular, the thermal conductivity of the screen-printed AlN layer was demonstrated by appling the rule of mixture in view point of thermal resistivity. Measured values of the thermal conductivity for AlN layers with the thickness of $53{\mu}m$ and $163{\mu}m$ showed $9.35W/m{\cdot}K$ and $12.40W/m{\cdot}K$, respectively.

Evaluation of Metal Composite Filaments for 3D Printing (3D 프린팅용 금속 입자 필라멘트의 물성 및 차폐 능력 평가)

  • Park, Ki-Seok;Choi, Woo-Jeon;Kim, Dong-Hyun
    • Journal of the Korean Society of Radiology
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    • v.15 no.5
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    • pp.697-704
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    • 2021
  • It is hard to get Filaments which are materials of the 3D printing Fused Deposition Modeling(FDM) method as radiation shielding in Korea. and also related research is insufficient. This study aims to provide basic data for the development of radiation shields using 3D printing by evaluating the physical properties and radiation shielding capabilities of filaments containing metal particles. after selecting five metal filaments containing metal particle reinforcement materials, the radiation shielding rate was calculated according to the Korean Industrial Standard's protective equipment test method to evaluate physical properties such as tensile strength, density, X-ray Diffraction(XRD), and weight measurement using ASTM's evaluation method. In the tensile strength evaluation, PLA + SS was the highest, ABS + W was the lowest, and ABS + W is 3.13 g/cm3 which value was the highest among the composite filaments in the density evaluation. As a result of the XRD, it may be confirmed that the XRD peak pattern of the particles on the surface of the specimen coincides with the pattern of each particle reinforcing material powder metal, and thus it was confirmed that the printed specimen contained powder metal. The shielding effect for each 3D printed composite filament was found to have a high shielding rate in proportion to the effective atomic number and density in the order of ABS + W, ABS + Bi, PLA+SS, PLA + Cu, and PLA + Al. In this study, it was confirmed that the metal particle composite filament containing metal powder as a reinforcing material has radiation shielding ability, and the possibility of using a radiation shielding filament in the future.

A Study of the Printability Coefficients on the Newspaper(III) - A study of the printability coefficients on the color newspaper printing - (신문용지의 인쇄적성 계수에 관한 연구(제3보) - 칼라 신문인쇄의 인쇄적성 계수 -)

  • Ha, Young-Baeck;Kim, Chang-Keun;Oh, Sung-Sang;Lee, Yong-Kyu;Koo, Chul-Whoi;Youn, Jong-Tae
    • Journal of Korea Technical Association of The Pulp and Paper Industry
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    • v.38 no.3 s.116
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    • pp.1-6
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    • 2006
  • The increasing use of newsprints in the media and an advertisement have brought the needs to improve the printing quality of the advance full-color newspaper. The printability coefficients used in this research such as Ymax for the density and Tollenaar's density smoothness constant value $\ulcorner$m$\lrcorner$ were introduced early in Europe and have been in use to control printing quality. In order to improve printing quality of domestic full-color newsprints, those printability coefficients could be used to control printing quality. This study was carried out to measure the printability coefficients of domestic full-color newspapers. Four kinds of domestic newspapers and two kinds of newspaper printing inks were tested by IGT printability tester. The printed density smoothness coefficient $\ulcorner$m$\lrcorner$ value showed good results when the samples have low porosity and roughness. The printability coefficients obtained are expected to be useful to the korean newspaper printing industry.

Synthesis of a New Cathode Redox Polymer for High Performance in Biofuel Cells

  • Choi, Young-Bong;Lee, Jung-Min;Kim, Hyug-Han
    • Bulletin of the Korean Chemical Society
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    • v.35 no.9
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    • pp.2803-2808
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    • 2014
  • High potential and fast electron transfer of a cathode mediator are significant factors for improving the performance of biofuel cells. This paper reports the first synthesis of a cathode redox polymer that is a coordination complex of poly (acrylic acid-vinylpyridine-acryl amide) (PAA-PVP-PAA) and [Os(4,4'-dicarboxylic acid-2,2'-bipyridine)$_2Cl_2]^{/+}$ ($E^{\circ}=0.48V$ versus Ag/AgCl). Bilirubin oxidase can be easily incorporated into this polymer matrix, which carried out the four-electron oxygen under typical physiological conditions (pH 7.2, 0.14 M NaCl, and $37^{\circ}C$). This new polymer showed an approximately 0.1 V higher redox potential than existing cathode mediators such as PAA-PVI-$[Os(dCl-bpy)_2Cl]^{+/2+}$. In addition, we suggest increasing the polymer solubility with two hydrophilic groups present in the polymer skeleton to further improve fast electron transfer within the active sites of the enzyme. The maximum power density achieved was 60% higher than that of PAA-PVI-$[Os(dCl-bpy)_2Cl]^{+/2+}$. Furthermore, high current density and electrode stability were confirmed for this osmium polymer, which makes it a promising candidate for high-efficiency biofuel cells.

Library Space Efficiency Improvement Through Closed Access System -Focused on Academic Libraries- (공간효율 개선을 위한 폐가식 도서관 운용 -지역 대학도서관 시설을 중심으로-)

  • Ahn, Joon Suk
    • Journal of the Korean Institute of Rural Architecture
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    • v.18 no.4
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    • pp.17-24
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    • 2016
  • Since the users have direct access to search and browse freely, the open access system has been employed to all the usual modern libraries. However, library space shortage problem created by the continuously increasing printed materials caused the degradation of usability and quality of the library space. Open Access system is superior in user convenience but is inferior in space efficiency. Keeping the open access system is considered as one of the reasons of the space shortage problem. Even though the closed access system does not provide free access or easy browsing for the uses, it's space efficiency is much higher than the open access system. The closed access system should be employed as a plan to relieve space shortage problem. Since the closed access system does not allow the public direct access to books, it is very economical. It also provides much better space efficiency with higher book shelving density. In this article, closed access library system models and their characteristics are examined as the reduction plans for the library space shortage problems.

Effect of Nano-Sized Silver Powders in CNT Paste on Field Emission Characteristics of Carbon Nanotube Cathode (탄소나노튜브 캐소드의 전계방출 특성에 미치는 CNT 페이스트용 나노입자 은분말의 영향)

  • An, Young-Je;Lee, Ji-Eon;Shin, Heon-Cheol;Cho, Young-Rae
    • Korean Journal of Materials Research
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    • v.18 no.1
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    • pp.12-17
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    • 2008
  • Carbon nanotube (CNT) cathodes were fabricated using nano-sized silver (Ag) powders as a bonding material between the CNTs and cathode electrodes. The effects of the powder size on the sintering behavior, the current density and emission image for CNT cathodes were investigated. As the diameter of the Ag powders decreases to 10 nm, the sintering temperature of the CNT cathode was lowered primarily due to the higher specific surface area of the Ag powders. In this study, it was demonstrated that nano-sized Ag powders can be feasibly used as a bonding material for a screen-printed CNT cathode, yielding a high current density and a uniform emission image.

A Study on Elbow Phantom Production and Usability Evaluation by Adjusting Infill Density using 3D Printing (3D 프린팅을 사용한 Infill 조절에 따른 Elbow 팬텀 제작 및 유용성 평가에 관한 연구)

  • Myung-In Kim;Seung-Ho Ji;Hyun-Seop Wi;Dae-Won Lee;Hui-Min Jang;Myeong-Seong Yun;Dong-Kyoon Han
    • Journal of the Korean Society of Radiology
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    • v.17 no.6
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    • pp.929-937
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    • 2023
  • Human equivalent phantoms manufactured using 3D printers are cheaper and can be manufactured in a short time than conventional human phantoms. However, many phantoms are manufactured with less than 100 % of Infill Density, one of the 3D printer output setting variables. Therefore, this study compared the Bone Phantom CT number, which differs from the ratio of five Infill Density produced using a 3D printer, to the CT number of the actual human body Bone. In addition, the usefulness of the manufactured phantom was evaluated by producing a 100 % elbow joint phantom with Infill Density and setting the Infill Density to 100 % through CT number comparison for each tissue on computed tomography (CT). As a result, the Bone Phantom printed with 100 % Infill Density did not show the most statistically significant difference from the CT number value of the actual human Bone, and the CT number of each tissue did not show a statistically significant difference from the CT number value of each tissue of the actual human elbow joint.

Patent Survey on Build-up PCB (Build-up PCB 특허출원동향)

  • Yeo Woon Dong;Kim Kang Hoe;Kim Jae Woo;Bae Sang Jin
    • Proceedings of the IEEK Conference
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    • 2004.06a
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    • pp.269-272
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    • 2004
  • Printed circuit boards (PCB) replaced conventional wiring in most electronic equipment I, reducing the size and weight of electronic equipment while improving reliability, uniformity, precision and performance. PCB is used in all kinds of electronic products because they can be mass-produced with very high circuit density and also enable easier trouble-shooting. This paper presents the analyses of the patent information of Build-up PCB which is seen as the most promising solution, as its substrate supports multi-level packaging, thinner board profiles and smaller pitches.

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Embedded Passives (내장형 수동소자)

  • 이호영
    • Journal of the Microelectronics and Packaging Society
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    • v.9 no.2
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    • pp.55-60
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    • 2002
  • The recent trend in electronic devices has been towards light weight, low cost, high performance and improved reliability. Passive components are very important parts of microelectronic devices. The number of passive components used in hand held devices and computers continue to increase. To achieve improvements in costs, component density, performance, and reliability, embedding of these passive components into the printed circuit boards (PCBs) is required. This paper introduces the embedding of passive components, and discusses the remained challenges in the commercialization of this technique.

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Back EMF Design of an AFPM Motor using PCB Winding by Quasi 3D Space Harmonic Analysis Method

  • Jang, Dae-Kyu;Chang, Jung-Hwan;Jang, Gun-Hee
    • Journal of Electrical Engineering and Technology
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    • v.7 no.5
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    • pp.730-735
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    • 2012
  • This paper presents a method to design the waveform of a back electromotive force (back EMF) of an axial flux permanent magnet (AFPM) motor using printed circuit board (PCB) windings. When the magnetization distribution of permanent magnet (PM) is given, the magnetic field in the air gap region is calculated by the quasi three dimensional (3D) space harmonic analysis (SHA) method. Once the flux density distribution in the winding region is determined, the required shape of the back EMF can be obtained by adjusting the winding distribution. This can be done by modifying the distance between patterns of PCB to control the harmonics in the winding distribution. The proposed method is verified by finite element analysis (FEA) results and it shows the usefulness of the method in eliminating a specific harmonic component in the back EMF waveform of a motor.