• 한국전기화학회:학술대회논문집
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• 한국전기화학회 2003년도 추계총회 및 학술발표회
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• pp.71-71
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• 2003

• 한국재료학회:학술대회논문집
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• 한국재료학회 2001년도 추계 학술발표강연 및 논문개요집
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• pp.83-83
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• 2001

• 한국원자력학회:학술대회논문집
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• 한국원자력학회 1999년도 추계학술발표회요약집
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• pp.382.1-382
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• 1999

• Bulletin of the Korean Chemical Society
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• 제27권6호
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• pp.869-874
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• 2006

We have carried out the Glaser oxidative coupling polymerizations of diethynyldiphenylsilane, diethynylmethylphenylsilane,diethynylmethyloctylsilane, and 1,2-diethynyl-1,1,2,2-tetramethyldisilane to afford polycarbosilanes containing diethynyl and organosilane groups in the main chain, such as poly(diethynyldiphenylsilane), poly(diethynylmethylphenylsilane), poly(diethynylmethyloctylsilane), and poly(1,2-diethynyl-1,1,2,2-tetramethyldisilane), respectively. These obtained materials are almost insoluble in common organic solvents such as $CHCl_3$ and THF probably due to the presence of a rigid rod diacetylene group along the polymer main chain. Therefore, the polymers were characterized using several spectroscopic methods in solid state. FTIR spectra of all the polymeric materials show that the characteristic $C \equiv C$ stretching frequencies appear at 2147-2154 $cm ^{-1}$, in particular. The polymers in the solid state exhibit that the strong maximum excitation peaks appear at 260-283 nm and the strong maximum fluorescence emission bands at 367-412 nm, especially. Thermogravimetric analysis of the materials shows that about 55-68% of the initial polymer weights remain at 400 ${^{\circ}C}$ in nitrogen.

• 비파괴검사학회지
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• 제32권2호
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• pp.131-141
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• 2012

A field theoretical approach to deformation and fracture of solid-state material is outlined, and its application to diagnosis of deformational status of metal specimens is discussed. Being based on a fundamental physical principle known as local symmetry, this approach is intrinsically scale independent, and capable of describing all stages of deformation on the same theoretical foundation. This capability enables us to derive criteria that can be used to diagnose transitions from the elastic to plastic regime, and the plastic to fracturing regime. For practical applications of these criteria, an optical interferometric technique known as electronic speckle-pattern interferometry is proved to be quite powerful; it is able to visualize the criteria as a whole image of the object on a real-time basis without numerical processing. It is demonstrated that this method is able to reveal loading hysteresis as well.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2008년도 International Meeting on Information Display
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• pp.1350-1352
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• 2008

Research on down conversion phosphor materials is the key for the development of solid state lighting (SSL). Especially finding alternative red phosphor for white LEDs based on blue or NUV LEDs are important research task. Under this view, we have synthesized a series of $Eu^{3+}$ substituted $La_2W_{2-x}Mo_xO_9$ (x = 0 ~ 2, insteps of 0.1) red phosphor and characterized by X-ray diffraction (XRD) and photoluminescence. XRD results reveal a phase transition from triclinic to cubic structure for $x\;{\geq}\;0$. All the compositions show broad charge transfer band due to charge transfer from oxygen to tungsten/molybdenum and red emission due to $Eu^{3+}$ ions. Select compositions show high red emission intensity compared to the commercial red phosphor under NUV/blue ray excitation. Hence, this candidate can be possible red emitting phosphors for white LEDs.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2001년도 The 6th International Symposium of East Asian Resources Recycling Technology
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• pp.581-585
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• 2001

Alinite-Calciumchloroaluminate system clinker was synthesized from solid state waste. The raw materials were municipal incineration ash, sewage sludge, limestone and clay. ecocement was prepared by the mixing of synthesized clinker and optimum amount of gypsum and its hydrolysis characteristic was investigated. X-ray diffraction, conduction calorimeter and reflecting microscope were used to analyze structural and physical properties. The main phase of clinker were alinite, calcium chloroaluminate. $C_2$S, $C_3$S. From the results of hardening time, hydration reactivity of synthesized all samples was faster than that of ordinary portland cement.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 춘계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.215-217
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• 2001

This paper describes an all solid-state switch pulse generator for various applications where square pulse voltage is required. The pulse generator produces various voltage pulses: voltage $5{\sim}100kV$. current $10{\sim}200A$, pulse width $1{\sim}10{\mu}sec$, repetition rate up to 500Hz. The output power is the combination of these parameters up to 10kW. It consists of a DC-DC converter and several pulse generating modules which are connected in series to obtain higher pulse voltage. Each module contains semiconductor switches (IGBT's), energy storage capacitors and control units to trigger switches. The structure and operational principle are described and the protection circuit for reliable operation is suggested. Experimental results show that the pulse generator can be used for applications with nonlinear loads.

• 대한금속재료학회지
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• 제50권9호
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• pp.691-695
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• 2012

Calcium phosphate ceramic composites, consisting of hydroxyapatite(HA) and tricalcium phosphate (TCP), were fabricated by solid state sintering in order to investigate the effect of their initial compositions on microstructural evolutions and biocompatibility. All the sintered calcium phosphate ceramics exhibited almost full densification, while the grain growth of the composites increased with an increasing TCP content in the green body. The TCP phase transformed into a Ca-deficient HA phase during sintering via the diffusion of calcium ions from the HA phase into the TCP phase. The phases formed in the composites significantly affected the biocompatibility of the composites. The HA-matrix ceramic composites with TCP had a better cellular response than the pure HA ceramics, presumably due to the newly formed Ca-deficient HA.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2006년도 6th International Meeting on Information Display
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• pp.1583-1586
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• 2006

All non-dopant white organic light-emitting diodes (WOLEDs) have been realized by using solid state highly fluorescent red bis(4-(N-(1- naphthyl)phenylamino)phenyl)fumaronitrile (NPAFN) and amorphous bipolar blue light-emitting 2-(4- diphenylamino)phenyl-5-(4-triphenylsilyl)phenyl- 1,3,4-oxadiazole (TPAOXD), together with well known green fluorophore tris(8- hydroxyquinolinato)aluminum $(Alq_3)$. The fabrication of multilayer WOLEDs did not involve the hard-tocontrol doping process. Two WOLEDs, Device I and II, different in layer thickness of $Alq_3$, 30 and 15 nm, respectively, emitted strong electroluminescence (EL) as intense as $25,000\;cd/m^2$. For practical solid state lighting application, EL intensity exceeding $1,000\;cd/m^2$ was achieved at current density of $18-19\;mA/cm^2$ or driving voltage of 6.5-8 V and the devices exhibited external quantum efficiency $({\eta}_{ext})$ of $2.6{\sim}2.9%$ corresponding to power efficiency $({\eta}_P)$ of $2.1{\sim}2.3\;lm/W$ at the required brightness.