• Applied Chemistry for Engineering
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• v.9 no.7
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• pp.961-967
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• 1998

In order to improve the optical properties and printability of paper, various fillers are used in papermaking. This study was performed to investigate several fillers-precipitated calcium carbonate(PCC), ground calcium carbonate(GCC), and blends(PCC/talc or micro-talc(MVP) and GCC/talc or micro-talc(MVP)-for their effects on various newsprint properties. Results obtained from the study were summarized as follows ; 1) PCC treatment gave about 16.8% higher retention than GCC treatment at the filler level of 5% and the retention of filler in the handsheet increased as average particle size of mixed filler was increasing($PCC{\leq}GCC<MVP<talc$). 2) PCC treatment kept opacity more highly than no filler treatment and opacity decreased as average particle size of mixed filler was increasing. 3) Independent treatment of PCC kept tear strength more effectively than GeC did, and tear strength increased as average particle size of mixed filler was increasing. 4) Independent treatment of pee kept tensile strength more highly than other treatments and Gee treatment kept tensile strength highly than pee treatment under mixed filler treatment. 5) Burst strength under PCC treatments decreased linearly as average particle size of mixed filler was increasing. 6) Compared "With non-filler treatment, filler treatment gave much better printability.

• Archives of design research
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• v.12 no.3
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• pp.43-52
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• 1999

For Bauhaus, the vaious typography experiments developed around the printing workshops, and it was only in the later Weimar Period that L. Moooly-Nagy, who came to be in charge of the rxinting workshops, approached it from the functional way of thinking and demanded print type reforms Using this as the basis, a new form of typograph called "typophoto" was developed by combining images and characters together using photography techniques and Bauhaus Unification Chaacter producyion. Harbert Bayer, striving at molds based on the ideologies of L. Moody-Nagy, prepared the framework for modern informational advertisements by producing a variety of advertisements based on several law of psychology and physiology. Bayer's successor, Joost Schmidt focused on lettering based on functionalism and typographic training and practice, while pioneering in the new area of display design wiwh efficient usage of space for exhibitions a1d dsplays. Thus, despite being carried doWl by the same leader in the sane era, the series of typographic experiments undertaken by the artists Bauhaus present guidelines to the direction modern visual communication must take through creativity and insight into the upcoming future that is not contained within the boundaries of traditions and customs.and customs.

• Proceedings of the KWS Conference
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• 2009.11a
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• pp.76-76
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• 2009

눈부신 전자산업의 발달로 대부분의 전자제품이 다기능/경박단소화 되고 있어, 고밀도 실장 기술인 양면 표면실장과 고집적 패키징 기술인 패키지 적층 공정의 적용이 점차 확대되고 있다. 따라서 양면 표면실장 및 패키지 적층 공정에 사용되는 저온 접합용 무연 솔더 즉, $183^{\circ}C$(Sn-37Pb 공정 솔더 융점) 이하의 융점을 가지는 저온 무연 솔더에 대한 관심이 높아지고 있다. 한편, 미세피치 적용 분야에 있어 ACF/P를 이용한 COG 접속 분야 외에도 최근 저온 접합용 무연 솔더를 이용한 접속 분야가 각광을 받고 있다. 따라서, 접속피치 미세화에 대응하기 위해 스크린 인쇄성을 향상시킬 수 있는 저온 무연 솔더 paste 제조 및 공정 기술의 개발이 필요한 실정이다. 현재 대표적인 저온 무연 솔더 조성은 Sn-Bi계($138^{\circ}C$ 융점)와 Sn-In계($120^{\circ}C$ 융점)이다. 하지만, 이들 조성의 신뢰성 등에 있어 개선의 여지가 있으므로 이를 해결하기 위한 무연솔더 조성의 개발이 필요하다. 이와 같은 관점에서, 본 연구는 $137^{\circ}C$의 융점을 갖는 Sn-57.6Ag-0.4Ag 저온 무연 솔더 paste를 $217^{\circ}C$의 융점을 갖는 Sn-3.0Ag-0.5Cu 솔더 paste와 비교하여 인쇄성, reflow 특성, void inspection, 미세조직 관찰 및 underfill 적용 등의 실험을 실시하였다.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.44 no.4
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• pp.77-84
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• 2012

The lithographic process depends on a satisfactory ink-in-water emulsion being formed during printing and the speed of wet presses makes the choice of fountain solution vitally important as the ink and fount must react quickly to form a stable emulsion. Ink and water come into contact with each other on the rolls of the press and are forced together in the roll nips. The water is not soluble in the ink since it is slightly fat. Instead, an emulsion is formed, a heterogeneous mass consisting of small water drops mixed into the ink, if the water feed is too great. This emulsification can affect the properties of an off-set ink and negatively affect the printability. So we investigated the effects of the emulsification of phenol free heat-set ink and existing heat-set ink on printed quality, such as amount of ink transfer, printed density, print-through and uniformity. We used Duke emulsification tester for the emulsification of inks, and used IGT printability tester for printed quality. The printed quality were measured by densitometer and were evaluated by the image analysis system. Compared to conventional printing ink, phenol-free ink showed better results of the printability at the emulsification.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2015.10a
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• pp.65-67
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• 2015

In this paper, small WLAN antenna was designed and investigated. Proposed antenna was configured for microstrip patch antenna ($29mm{\times}29mm$) that was mounted on RF4 dielectric substrate (relative permittivity 4.4, thick 1.6mm, tangent loss 0.025) with $45mm{\times}45mm$. In order to obtain a wide band characteristic, the cutting process was 3.2mm diagonal corners of the patch antenna located on the top of the substrate. Antenna feeding position for 50 ohm impedance matching was decided to be 5.1mm at the central axis in the horizontal direction. As a result, frequency bandwidth satisfying the condition of VSWR<2dB was 2.365-2.45GHz (85MHz, 3.53%) for considering WLAN.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.12
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• pp.2816-2822
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• 2014

In this paper, a wideband loop antenna for UWB applications is studied. The structure of the proposed wideband loop antenna is a circular loop antenna with appended circular sectors to obtain an ultra-wideband characteristic. The circular sectors are used instead of conventional triangular sectors to match with the 50 ohm feed line. Optimal design parameters are obtained by analyzing the effects of the gap between the circular sectors and the radius of the circular loop on the input reflection coefficient and gain characteristics. The optimized wideband loop antenna is fabricated on an FR4 substrate with a dimension of 41 mm by 41 mm. Experiment results show that the proposed antenna has a frequency band of 3.1-11.0 GHz for a VSWR < 2.25, which assures the operation in the UWB band. Measured gain ranges 1.3-5.3 dBi in the UWB band.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.11
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• pp.695-700
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• 2018

This paper presents the development of compact and lightweight broadband power amplifier module using HMIC (Hybrid Microwave Integrated Circuit) technology that could be high-density integration for many non-packaged microwave components into the small area of a high dielectric constant printed circuit board, such as a ceramic substrate, also using the special design and fabrication schemes for the structure of minimized electromagnetic interference to obtain the homogeneous electrical performance at the wideband frequency. The results confirmed that the small signal gain has a gain flatness of ${\pm}1.5dB$ within the range of 32 to 36 dB. In addition, the output power satisfied more than 30 dBm. The noise figure was measured within 7 dB, and OIP3 (Output Third Order Intercept Point) was more than 39 dBm. The fabricated broadband power amplifier satisfied the target specification required to electrically drive the high power amplifiers of jamming generators for electronic warfare, so the actual applicability to the system was verified. Future studies will be aimed at designing other similar microwave power amplifiers in the future.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.46 no.3
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• pp.1-10
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• 2014

Offset paper printing is a promising roll-to-roll technique for color printed materials. Although it is no doubt that understanding ink transfer mechanism in offset printing process is necessary to achieve high printing quality, investing the relationship between inks and substrates at the nip is difficult experimentally due to high printing speed. In this paper, rheological behavior and splitting point of the ink at the nip is studied using package software Ployflow and Flow 3D based on Navier-Stokes equation. Polydimethylsiloxane (PDMS) ink and IGT printability tester were used for an model ink and experiment to compare with that of simulation data, respectively. As a result, higher viscosity at state flow and pressure increased ink transfer due to higher possibility of presence of cavitation at the nip and increase in covering area ratio. These results have shown good agreements with experimental data compared by measuring density of print through.

• Journal of the Microelectronics and Packaging Society
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• v.30 no.2
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• pp.1-12
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• 2023

In the current era of the global mobile smart device revolution, electronic devices are required in all spaces that people interact with. The establishment of the internet of things (IoT) among smart devices has been recognized as a crucial objective to advance towards creating a comfortable and sustainable future society. In-mold electronic (IME) processes have gained significant industrial significance due to their ability to utilize conventional high-volume methods, which involve printing functional inks on 2D substrates, thermoforming them into 3D shapes, and injection-molded, manufacturing low-cost, lightweight, and functional components or devices. In this article, we provide an overview of IME and its latest advances in application. We review biomimetic nanomaterials for constructing self-supporting biosensor electronic materials on the body, energy storage devices, self-powered devices, and bio-monitoring technology from the perspective of in-mold electronic devices. We anticipate that IME device technology will play a critical role in establishing a human-machine interface (HMI) by converging with the rapidly growing flexible printed electronics technology, which is an integral component of the fourth industrial revolution.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.3
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• pp.547-551
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• 2010

In this paper, Double rectangular patch with 4-bridges is investigated for solution of IEEE 802.11b/g(2.4GHz) and 802.11a(5.7GHz). Rectangular patch for 5.7GHz frequency band is printed on the PCB substrate and connected to another rectangular patch for 2.4GHz frequency band with 4-bridges to obtain dual band operation in a antenna element. The proposed antenna has a low profile and is fed by $50{\Omega}$ coaxial line. The dielectric constant of the designed antenna substrate is 3.27. Two rectangular patches have each resonance frequencies that are 2.4GHz and 5.7GHz. A dual-band characteristic is shown as connecting two rectangular patch using four bridges. Also, the proposed antenna is shown input return loss that is below -10dB at 2.4GHz and 5.7GHz of WLAN(Wireless LAN).