• ETRI Journal
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• 제39권5호
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• pp.632-642
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• 2017

Digital all-optical parallel computing is an important research direction and spans conventional devices and convergent nano-optics deployments. Optical bus-based interconnects provide interesting aspects such as relative information communication speed-up or slow-down between optical signals. This aspect is harnessed in the newly proposed All-Optical Linear Array with a Reconfigurable Pipelined Bus System (OLARPBS) model. However, the physical realization of such communication interconnects needs to be considered. This paper considers spatial layouts of processing elements along with the optical bus light paths that are necessary to realize the corresponding interconnection requirements. A metric in terms of the degree of required physical constraint is developed to characterize the variety of possible solutions. Simple algorithms that determine spatial layouts are given. It is shown that certain communication interconnection structures have associated intrinsic topologies.

• 한국공작기계학회논문집
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• 제12권5호
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• pp.40-45
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• 2003

Optical and electronic industries are using lapping and polishing processing as a final finish rather than grinding, because they need more accurate parts of brittles non-metallic materials such as single crystals. Sapphire has been ground by the ultra-precision surface grinder having a glass -ceramic spindle of extremely-low thermal expansion with various cup-type resinoid-bonded diamond wheels of #400-#3000 in grain size. Sapphire can be ground in the ductile mode. And also, the surface roughness and grinding conditions has been clarified. The smooth surface of Sapphire less than 1nm RMS, 1nm Ra can be obtained by the ultra-precision grinding without any polishing process.

• 한국전기전자재료학회논문지
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• 제21권5호
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• pp.397-401
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• 2008

Most of the topic in PCB industry was about increasing the volume of product for the development of electronics in numerous industrial application area. However, it has been emerged that yield improvement quality manufacturing via detecting any suspicious process in order to minimize the scrapped product and material waste. In addition, recently, restriction of hazardous substances (RoHS) claims that electronic manufacturing environment should reduce the harmful chemicals usage, thus the importance of monitoring copper etchant and detecting any mis-processing is crucial for electronics manufacturing. In this paper, we have developed real-time chemical monitoring system using RGB sensor, which is simpler but more accurate method than commercially utilized oxidation reduction potential (ORP) technique. The developed Cu etchant monitoring system can further be utilized for copper interconnect process in future nano-semiconductor process.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2005년도 하계학술대회 논문집 Vol.6
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• pp.643-644
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• 2005

New methods of nano-sized material and composite coating preparations have been considered on the base of mathematical model of abrasion-reaction interaction of milling and grinding bodies in planetary centrifugal mill. The essence of the method is the abrasive and oxidative wear of the milling bodies and amorphous (better inert) additives. Interactions between them has been supplied the necessary impulse of pressure and temperature on the impact-frictional contacts and promoted chemical processes. The offered method can find application for such processing as sintering and geological minerals opening.

• Bulletin of the Korean Chemical Society
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• 제21권6호
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• pp.604-610
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• 2000

Drying-step in sol-gel processing was bypassed by exchanging alcoholic solvent in forsterite alcogel directly with MMA. By in-situ polymerization of the MMA, organic-inorganic nano-composite of PMMA-forsterite was prepared. As porous nature of inorganic networks in the gel was preserved and fixated in the composite, spherical morphology of PMMA was resulted. The PMMA-forsterite composite was optically transparent, machinable,mechanically sustainable, and thermally more stable than pristine PMMA. When doped with $Eu^{+3}$, inorganic moiety in the composite provided site environment that is very different from that in pristine PMMA. Prominent $^{5}D_0$ → $^{7}F_0$ transition at 578 nm, broken degeneracy in $^{5}D_0$ → $^{7}F_1$ and $^{5}D_0$ →$^{7}F_2$ transitions suggested that $Eu^{+3}$ was exclusively doped in the inorganic moiety of the composite, which had lower symmetry than the organic counterpart.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2007년도 춘계학술대회 논문집
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• pp.379-382
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• 2007

The MEMS (Micro Electro Mechanical Systems) process is used in a micro/nano pattern manufacturing method. This method is based on the lithography technology. But the MEMS process has some problems such as complicated process, long processing time and high production costs. Many researchers are doing research in substitute manufacturing method to work out a solution to these problems. In this paper, we apply a dieless incremental forming technology to a substitute method of MEMS process. This dieless forming technology is using in the commercial scale sheet forming such as a prototype of automobile sheet parts. 5-axes CNC (Computerized Numeric Control) method are applied in this system to get a micro-scale dieless forming results. These 5-axes system are composed of precision AC servo motor stages (4-axes) and PZT actuator (1-axis). A PZT actuator is used in a precision actuating axis because it can be operated in the nano scale stroke resolution. This micro dieless incremental forming system has the advantage of minimization in manipulating distance and working space. As equipment and tools become smaller in size, minute inertia force and high natural frequency can be obtained. Therefore, high precision forming performance can be obtained. This allows the factory to quickly provide the customer with goods because the manufacturing system and process are reduced. To construct this micro manufacturing system, many technologies are necessary such as high stiffness frame, high precision actuating part, structural analysis, high precision tools and system control. To achieve the optimal forming quality, the micro dieless forming system is designed and made with high stiffness characteristic.

• 한국정보과학회논문지:컴퓨팅의 실제 및 레터
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• 제14권1호
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• pp.13-21
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• 2008

일반적으로 센서노드간의 데이타통신은 내부처리나 센싱 작업보다 더 많은 에너지 소모를 요구한다. 본 논문에서는, 내용인지(context-aware) 라우팅 테이블(routing table)을 이용하여 인접한 노드간의 질의 송수신을 위해 필요한 패킷 송신 수를 줄여 질의 최적화를 수행하는 새로운 아이디어를 제안한다. 내용인지 라우팅 테이블에는 현재 노드로부터 도달 가능한 하위노드에서 측정할 수 있는 센서의 종류에 관한 정보가 저장되어 있다. 내용인지 라우팅 정보를 이용하여 각 노드는 자식노드에게 불필요한 질의 송신이나 결과 전달을 차단함으로써 불필요한 패킷 송신의 수를 줄일 수 있다. 본 논문에서 제안한 방법을 바탕으로 한 시뮬레이션에서 최대 약 80%의 성능 효과를 보였다.

• Bulletin of the Korean Chemical Society
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• 제33권2호
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• pp.541-548
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• 2012

New candidates composed of anthracene and 4-alkylethynylbenzene end-capped oligomers for OTFTs were synthesized under Sonogashira coupling reaction conditions. All oligomers were characterized by FT-IR, mass, UV-visible, and PL emission spectrum analyses, cyclic voltammetry (CV), differential scanning calorimetry (DSC), thermal gravimetric analysis (TGA), $^1H$-NMR, and $^{13}C$-NMR. Investigation of their physical properties showed that the oligomers had high oxidation potential and thermal stability. Thin films of DHPEAnt and DDPEAnt were characterized by spin coating them onto Si/$SiO_2$ to fabricate top-contact OTFTs. The devices prepared using DHPEAnt and DDPEAnt showed hole field-effect mobilities of $4.0{\times}10^{-3}cm^2$/Vs and $2.0{\times}10^{-3}cm^2$/Vs, respectively, for solution-processed OTFTs.

• 한국재료학회지
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• 제22권4호
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• pp.207-210
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• 2012

The preparation of $Sm_2O_3$ doped $CeO_2$ in Igepal CO-520/cyclohexane reverse micelle solutions has been studied. In the present work, we synthesized nanosized $Sm_2O_3$ doped $CeO_2$ powders by reverse micelle process using aqueous ammonia as the precipitant; hydroxide precursor was obtained from nitrate solutions dispersed in the nanosized aqueous domains of a micro emulsion consisting of cyclohexane as the oil phase, and poly (xoyethylene) nonylphenylether (Igepal CO-520) as the non-ionic surfactant. The synthesized and calcined powders were characterized by Thermogravimetry-differential thermal analysis (TGA-DTA), X-ray diffraction analysis (XRD), and Transmission electron microscopy (TEM). The crystallite size was found to increase with increase in water to surfactant (R) molar ratio. Average particle size and distribution of the synthesized $Sm_2O_3$ doped $CeO_2$ were below 10 nm and narrow, respectively. TG-DTA analysis shows that phase of $Sm_2O_3$ doped $CeO_2$ nanoparticles changed from monoclinic to tetragonal at approximately $560^{\circ}C$. The phase of the synthesized $Sm_2O_3$ doped $CeO_2$ with heating to $600^{\circ}C$ for 30 min was tetragonal $CeO_2$. This study revealed that the particle formation process in reverse micelles is based on a two step model. The rapid first step is the complete reduction of the metal to the zero valence state. The second step is growth, via reagent exchanges between micelles through the inter-micellar exchange.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2016년도 제50회 동계 정기학술대회 초록집
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• pp.189-189
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• 2016

Recently, many researchers have shown an increased interest in colloidal quantum dots (QDs) due to their unique physical and optical properties of size control for energy band gap, narrow emission with small full width at half maxima (FWHM), broad spectral photo response from ultraviolet to infrared, and flexible solution processing. QDs can be widely used in the field of optoelectronic and biological applications and, in particular, colloidal QDs based light emitting diodes (QDLEDs) have attracted considerable attention as an emerging technology for next generation displays and solid state lighting. A few methods have been proposed to fabricate white color QDLEDs. However, the fabrication of white color QDLEDs using single QD is very challenging. Recently, hybrid nanocomposites consisting of CdTe/ZnO heterostructures were reported by Zhimin Yuan et al.[1] Here, we demonstrate a novel but facile technique for the synthesis of CdTe/ZnO/G.O(graphene oxide) quasi-core-shell-shell quantum dots that are applied in the white color LED devices. Our best device achieves a maximum luminance of 484.2 cd/m2 and CIE coordinates (0.35, 0.28).