• Carbon letters
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• v.25
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• pp.60-67
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• 2018

In the present work, capability of thymolphthalein-grafted graphene oxide, which was successfully synthesized in this study, in stabilization of polypropylene against thermal oxidation were investigated and compared with that of SONGNOX 1010, a commercially used phenolic antioxidant for the polymer. The modified graphene oxide were incorporated into polypropylene via melt mixing. State of distribution of the nanoplatelets in the polymer matrix was examined using scanning electron microscopy and was shown to be homogeneous. Measurements of oxidation onset temperature and oxidative induction time revealed that thymolphthalein-grafted graphene oxide modifies thermo-oxidative stability of the polymer in the melt state remarkably. However, the efficiency of the nanoplatelets in stabilization of polypropylene against thermal oxidation in melt state was shown to be inferior to that of SONGNOX 1010. Furthermore, oven ageing experiments followed by Fourier transform infrared spectroscopy showed that the modified graphene oxide improves thermo-oxidative stability of the polymer strongly in the solid state, so that its stabilization efficiency is comparable to that of SONGNOX 1010.

• Electronics and Telecommunications Trends
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• v.34 no.5
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• pp.99-112
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• 2019

A quantum light source is an essential element for quantum information technology, including quantum communication, quantum sensor, and quantum computer. Quantum light sources including photon number state, entangled state, and squeezed state can be divided into two types according to the generation mechanism, namely single emitter and non-linear based systems. The single emitter platform contains atom/ion trap, solid-state defect/color center, two-dimensional material, and semiconductor quantum dot, which can emit deterministic photons. The non-linear based platform contains spontaneous parametric down-conversion and spontaneous four-wave mixing, which can emit probabilistic photon pairs. For each platform, we give an overview of the recent research trends of the generation, manipulation, and integration of single photon and entangled photon sources. The characteristics of quantum light sources are investigated for each platform. In addition, we briefly introduce quantum sensing, quantum communication, and quantum computing applications based on quantum light sources. We discuss the challenges and prospects of quantum light sources for quantum information technology.

• Journal of the Korean Chemical Society
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• v.37 no.12
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• pp.995-1002
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• 1993

The thermal decomposition of trimethylaluminum (TMA) with ammonia has been investigated by in-situ Fourier transform infrared spectroscopy. The spectroscopic reaction cell, which permits heating interna lly up to 1100$^{\circ}C$, consists of stainless-steel hexagonal-port chamber containing two NaCl windows installed in parallel. In this work, the stoichiometric reaction between TMA and $NH_3$ is found to be completed immediately after mixing. FTIR spectra observed in the range of temperature 25∼1100$^{\circ}C$ show that TMA and TMA : $NH_3$ adduct decompose into methane as a predominant product around 500$^{\circ}C$. The assignments of the IR bands due to the gaseous TMA, $NH_3$ and TMA : $NH_3$ adduct are attempted on the basis of the published data. Furthermore, the decomposition of TMA can be described as a first-order reaction. Kinetic data about the decompositon of TMA and TMA : $NH_3$adduct will also be discussed.

• KSBB Journal
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• v.23 no.4
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• pp.345-349
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• 2008

To enhance the value as a feedstuff of distiller's dried grain (DDG) and develop fermented feedstuff, we investigated the effects of the culture conditions affecting glucoamylase activity, such as pH in submerged culture and moisture content in solid-state culture. Also, we investigated the optimal mixing ratio of DDG and wheat bran for the production of fermented feedstuff containing high content of amino acids. In culture conditions for high fermented activity, pH and moisture were optimum at pH 4 and 60%, respectively. In the case of mixing ratio, the glucoamylase activity was decreased with increase of DDG content. On the other hand, the content of crude protein was increased slowly. For the development of fermented feedstuff, the optimal mixing ratio of DDG and wheat bran was 1 to 4. Finally, we could produce approximately 1 ton (dry matter) of trial product in incubator of pilot-scale. The glucoamylase activity and the crude protein content were 1,024 U/g and 33.6%, respectively.

• Journal of the Korean Ceramic Society
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• v.42 no.9 s.280
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• pp.631-636
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• 2005

$LiNi_{1-y}Ga_yO_2$ (y = 0.005, 0.010, 0.025, 0.050, and 0.100) were synthesized by the solid-state reaction method after mechanical mixing, and their_electrochemical properties were investigated. All the $LiNi_{1-y}Ga_yO_2$ (y=0.005, 0.010, 0.025, 0.050, and 0.100) samples had the R3m structure. The sample with y = 0.025 showed the largest first discharge capacity (131.4 mAh/g) and good cycling performance [discharge capacity 117.5 mAh/g ($89.4{\%}$ of the first discharge capacity) at the 20th cycle]. The first discharge capacity decreased as the value of y increased. The samples with y = 0.010 and y = 0.005 had small R-factor but their cycling performance was worse than that of the sample with y = 0.025. All the $LiNi_{1-y}Ga_yO_2$ samples had smaller discharge capacities than $LiNiO_2$, but their cycling performances were better than that of $LiNiO_2$.

• Journal of the Korean Ceramic Society
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• v.34 no.7
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• pp.703-712
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• 1997

The PTCR devices of BaTiO3 doped with Sb2O3, SiO2 were prepared by Liquid Addition Method(LPAM) where doping sources were used in the forms of Liquid. The amounts of doping in LPMA is smaller than that in solid state mixing method. Also the doping process in LPMA is very suitable for BaTiO3-based PTCR devices because it is easy to obtain homogeneous mixing and reproductivity. By optimizing the doping condition in BaTiO3 system, (0.09 mol% Sb2O3, 0.25 wt% SiO2 and 0.02 wt% MnO2) it was possible to fabricate BaTiO3-based PTCR devices whee the room-temperature resistivity and specific resistivity were 15{{{{ OMEGA }}cm and 2$\times$106 respectively.

• Journal of the Korean Vacuum Society
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• v.6 no.S1
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• pp.127-132
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• 1997

Microstructure of the Fe-Ti system by ion beam mixing of multilayers at 300 K and 77 K has been studied in a wide composition range. The ion bombardment was carried out using $Ar^+$ ions at 80 keV. Using grazing angle x-ray diffraction we find that the lattice parameters of these bcc solid solutions are very close to that of $\alpha$-Fe. Extended x-ray absorption fine-structure spectroscopy have been performed to investgate the short-range order in the ion-beam-mixed state. The structure parameters, such as the interatomic distance and the coordination number are estmated from the Fe K-edge Fourier filtered EXAFS spectra. The interatomic distance is independent of the alloy concentration and it is almost constant. The study of x-ray absorption near-edge structure gives information on the individual $\rho$components of the partial densityof states of the conduction band of the Fe and Ti We also find that a charge transfer from Ti to Fe atoms takes place.

• Journal of the Korean Magnetic Resonance Society
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• v.3 no.2
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• pp.90-99
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• 1999

Doping of boron atoms in graphite has been well known method to increase the discharge capacity as the negative electrode material for lithium secondary battery. Herein, the boron-doped graphites are prepared by mixing 1, 2.5, 5, and 7 wt. % of boron carbide in carbon during the graphitizing process. The structural states of boron in boron-doped graphites are investigated by solid-state 11B NMR spectroscopy. The resonance lines for substitutional boron atoms are identified as the second order quadrupolar powder pattern with the quardrupole coupling constant, QCC = 3.36(2) MHz. The quantitative analysis of 11B NMR spectra with boron-doped graphite has also been performed via simulation.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2009.05a
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• pp.425-428
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• 2009

Silicone is recently used for LED chip encapsulment due to its good thermal stability and optical transmittance. To mold a solid-state silicone encapsulment, curing by mixing at elevated temperatures followed by cooling is necessary. As the silicone molding process is involved in healing and subsequent cooling, the thermal residual stress, which causes mechanical warpage or optical birefringence in the final silicone encapsulment, may be induced if there are non-uniformities in cured silicone material properties or encapsulment shape design. The prediction of residual stress is necessary to design a high-quality silicone molding process. Therefore, in the present paper, a numerical parametric study was attempted to evaluate the heating and cooling effects on the thermal residual stress induced in the cured silicone.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.2
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• pp.224-227
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• 2006

We have chained 459nm blue laser radiation generated by intracavity sum frequency generation( SFG ) due to the mixing of the 1064 nm laser output of a Nd:YVO4 pumped by diode and the 809nm radiation from higg-power semiconductor laser(500mW). The maximum blue output power of 0.95 mW was obtained using 400 mW input power of semiconductor laser at the type II phase matching condition (${\psi}=90^{\circ}\;{\theta}=90^{\circ}$). The threshold input power of blue laser generation was 120 mW.