• 한국축산식품학회지
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• 제36권5호
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• pp.671-678
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• 2016

Fractioning and/or preheating treatment on the rheological properties of myofibrillar protein (MP) gels induced by microbial transglutaminase (MTG) has been reported that they may improve the functional properties. However, the optimum condition was varied depending on the experimental factors. This study was to evaluate the effect of red bean protein isolate (RBPI) on the rheological properties of MP gels mediated by MTG as affected by modifications (fractioning: 7S-globulin of RBPI and/or preheat treatment (pre-heating; 95℃/30 min): pre-heating RBPI or pre-heating/7S-globulin). Cooking yields (CY, %) of MP gels was increased with RBPI (p<0.05), while 7S-globulin decreased the effect of RBPI (p<0.05); however, preheating treatments did not affect the CY (p>0.05). Gel strength of MP was decreased when RBPI or 7S-globulin added, while preheat treatments compensated for the negative effects of those in MP. This effect was entirely reversed by MTG treatment. Although the major band of RBPI disappeared, the preheated 7S globulin band was remained. In scanning electron microscopic (SEM) technique, the appearance of more cross-linked structures were observed when RBPI was prepared with preheating at 95℃ to improve the protein-protein interaction during gel setting of MP mixtures. Thus, the effects of RBPI and 7S-globulin as a substrate, and water and meat binder for MTG-mediated MP gels were confirmed to improve the rheological properties. However, preheat treatment of RBPI should be optimized.

• 한국재료학회지
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• 제24권7호
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• pp.370-374
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• 2014

Inorganic pigments have high thermal stability and chemical resistance at high temperature. For these reasons, they are used in clay, paints, plastic, polymers, colored glass and ceramics. $CoAl_2O_4$ nano-powder was synthesized by reverse-micelle processing the mixed precursor(consisting of $Co(NO_3)_2$ and $Al(NO_3)_3$). The $CoAl_2O_4$ was prepared by mixing an aqueous solution at a Co:Al molar ratio of 1:2. The average particle size, and the particle-size distribution, of the powders synthesized by heat treatment (at 900; 1,000; 1,100; and $1,200^{\circ}C$ for 2h) were in the range of 10-20 nm and narrow, respectively. The average size of the synthesized nano-particles increased with increasing water-to-surfactant molar ratio. The synthesized $CoAl_2O_4$ powders were characterized by X-ray diffraction analysis(XRD), field-emission scanning electron microscopy(FE-SEM) and color spectrophotometry. The intensity of X-ray diffraction of the synthesized $CoAl_2O_4$ powder, increased with increasing heating temperature. As the heating temperature increased, crystal-size of the synthesized powder particles increased. As the R-value(water/surfactant) and heating temperature increased, the color of the inorganic pigments changed from dark blue-green to cerulean blue.

• 한국축산식품학회지
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• 제33권1호
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• pp.67-74
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• 2013

The aims of this research were to produce oil-in-water ${\beta}$-lactoglobulin/alginate (${\beta}$-lg/Al) nanoemulsions loaded with coenzyme $Q_{10}$ and to investigate the combined effects of heating temperature and alginate concentration on the physicochemical properties and encapsulation efficiency of ${\beta}$-lg/Al nanoemulsions. In ${\beta}$-lg/Al nanoemulsions production, various heating temperatures (60, 65, and $70^{\circ}C$) and alginate concentrations (0, 0.01, 0.03, and 0.05%) were used. A transmission electron microscopy was used to observe morphologies of ${\beta}$-lg/Al nanoemulsions. Droplet size and zeta-potential values of ${\beta}$-lg/Al nanoemulsions and encapsulation efficiency of coenzyme $Q_{10}$ were determined by electrophoretic light scattering spectrophotometer and HPLC, respectively. The spherically shaped ${\beta}$-lg/Al nanoemulsions with the size of 169 to 220 nm were successfully formed. The heat treatments from 60 to $70^{\circ}C$ resulted in a significant (p<0.05) increase in droplet size, polydispersity, zeta-potential value of ${\beta}$-lg/Al nanoemulsions, and encapsulation efficiency of coenzyme $Q_{10}$. As alginate concentration was increased from 0 to 0.05%, there was an increase in the polydispersity index of ${\beta}$-lg/Al nanoemulsions and encapsulation efficiency of coenzyme $Q_{10}$. This study demonstrates that heating temperature and alginate concentration had a major impact on the size, polydispersity, zeta-potential value and encapsulation efficiency of coenzyme $Q_{10}$ in ${\beta}$-lg/Al nanoemulsions.

• The Korean Journal of Ceramics
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• 제6권2호
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• pp.129-133
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• 2000

Boron nitride films were synthesized with $N_2$ion flux of low energy, up to 100 eV, at different substrate temperatures of no heating, 200, 400, 500, and $800^{\circ}C$, respectively. Boron was supplied by e-beam evaporation at the rate of $1.5\AA$/sec. For all the conditions, hexagonal BN (h-BN) phase was mainly synthesized and high resolution transmission electron microscopy (HRTEM) showed that (002) planes of h-BN phase were aligned vertical to the Si substrate. The maximum alignment occurred around $400^{\circ}C$. In addition to major h-BN phase, transmission electron diffraction (TED) rings identified the formation of cubic BN (c-BN) phase. But HRTEM showed no distinct and continuous c-BN layer. These results suggest that c-BN phase may form in a scattered form even when h-BN phase is mainly synthesized under small momentum transfer by bombarding ions, which are not reconciled with the macro compressive stress model for the c-BN formation.

• 한국세라믹학회지
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• 제46권3호
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• pp.242-248
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• 2009

Forsterite is a crystalline magnesium silicate with chemical formula $Mg_2SiO_4$, which has extremely low electrical conductivity that makes it an ideal substrate material for electronics. In this study, forsterite precursors were synthesized with magnesium silicate gels from the mixture of magnesium nitrate solution and various sodium silicate solution by the geopolymer technique. Precursors and heattreated powders were characterized by thermogravimetrical differential thermal analyzer(TG-DTA), X-ray diffractometer(XRD), scanning electron microscopy(SEM), Si magic angle spinning nuclear magnetic resonance(MAS-NMR), transmission electron microscopy(TEM). As the result of analysis about the crystallization behavior by DTA, the synthesized precursors were crystallized in the temperature range of $700^{\circ}C$ to $900^{\circ}C$. The XRD results showed that the gel composition began to crystallize at various temperature. Also, it was found that the sodium orthosilicate based precursors(named as 'FO') began to crystallize at above $550^{\circ}C$. The FO peaks were much stronger than sodium silicate solution based precursors(named as 'FW'), sodium metasilicate based precursors(named as 'FM') at $800^{\circ}C$. TEM investigation revealed that the 100nm particle sized sample was obtained from FO by heating up to $800^{\circ}C$.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2015년도 제49회 하계 정기학술대회 초록집
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• pp.221.2-221.2
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• 2015

Graphene is very interesting 2 dimensional material providing unique properties. Especially, graphene has been investigated as a stretchable and transparent conductor due to its high mobility, high optical transmittance, and outstanding mechanical properties. On the contrary, high sheet resistance of extremely thin monolayer graphene limits its application. Artificially stacked multilayer graphene is used to decrease its sheet resistance and has shown improved results. However, stacked multilayer graphene requires repetitive and unnecessary transfer processes. Recently, growth of multilayer graphene has been investigated using a chemical vapor deposition (CVD) method but the layer controlled synthesis of multilayer graphene has shown challenges. In this paper, we demonstrate controlled growth of multilayer graphene using a two-step process with multi heating zone low pressure CVD. The produced graphene samples are characterized by optical microscope (OM) and scanning electron microscopy (SEM). Raman spectroscopy is used to distinguish a number of layers in the multilayer graphene. Its optical and electrical properties are also analyzed by UV-Vis spectrophotometer and probe station, respectively. Atomic resolution images of graphene layers are observed by high resolution transmission electron microscopy (HRTEM).

• 한국진공학회:학술대회논문집
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• 한국진공학회 2013년도 제44회 동계 정기학술대회 초록집
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• pp.662-662
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• 2013

Over the last several decades, innovative light-harvesting devices have evolved to achieve high efficiency in solar energy transfer. Research on the mechanisms for plasmon resonance is very desirable to overcome the conventional efficiency limits of photovoltaics. The influence of localized surface plasmon resonance on hot electron flow at a metal-semiconductor interface was observed with a Schottky diode composed of a thin silver layer on $TiO_2$. The photocurrent is generated by absorption of photons when electrons have enough energy to travel over the Schottky barrier and into the titanium oxide conduction band. The correlation between the hot electrons and the surface plasmon is confirmed by matching the range of peaks between the incident photons to current conversion efficiency (IPCE, flux of collected electrons per flux of incident photons) and UV-Vis spectra. The photocurrent measured on Ag/$TiO_2$ exhibited surface plasmon peaks; whereas, in contrast to the Au/$TiO_2$, a continuous Au thin film doesn't exhibit surface plasmon peaks. We modified the thickness and morphology of a continuous Ag layer by electron beam evaporation deposition and heating under gas conditions and found that the morphological change and thickness of the Ag film are key factors in controlling the peak position of light absorption.

• 한국세라믹학회지
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• 제18권1호
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• pp.27-34
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• 1981

The phase separation of low-alkali borosilicate glass with the composition of $6.25Na_2O$.$18.75B_2O_3$.$75.00SiO_2$(mole%) substituting $Li_2O$ for $Na_2O$ was studied. The phase separation in the temperature range of transformation was examined with various heating temperatures and soaking times. Durability to water, thermal expansion and specific density of the specimen were investigated and the microstructure of the separated phase was also observed by transmission electron micrograph techniques. The maximum alkali extraction result with the best phase separation effect was obtained when $Na_2O$ of the base glass was replaced with $1.88Li_2O$ (mole %) and electron micrograph of carbon film replica of $1.88Li_2O$$4.37Na_2O$.$18.75B_2O_3$.$75.00SiO_2$ (mole %) glass showed that the glass consisted of homogeneous two phases. The minimum specific density was shown with the specimen treated at 57$0^{\circ}C$ and it was also shown that the longer the treating time the lower the specific density. The apparent activation energies of approximately 45 kcal/mole by the alkali extraction and 43kcal/mole by the thermal expansion method were derived from the Arrhenius plots, respectively.

• Bulletin of the Korean Chemical Society
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• 제35권8호
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• pp.2477-2480
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• 2014

Thermal degradation of titanium-containing metal-organic frameworks (MOFs; MIL-125 and MIL-125-$NH_2$ at $350^{\circ}C$ for 6 h in air produced $TiO_2$ nanoparticles of ca. 10 nm in diameter. Scanning electron and transmission electron microscope analyses indicated that those nanoparticles were aggregated randomly within each crystalline particle of their MOF precursors. The $TiO_2$ nanoparticles prepared from MIL-125-$NH_2$ exhibited higher activity for the degradation of 4-chlorophenol under visible light.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2011년 춘계학술대회논문집
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• pp.117-123
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• 2011

The low electric power and high efficiency chips are required because of the appearance of smart phones. Also, high-capacity memory chips are needed. e-MMC(embedded Multi-Media Card) for this is defined by JEDEC(Joint Electron Device Engineering Council). The e-MMC memory for research and development is a memory mulit-chip module of 64GB using 16-multilayers of 4GB NAND-flash memory. And it has simplified the chip by using SIP technique. But mulit-chip module generates high heat by higher integration. According to the result of study, whenever semiconductor chip is about 10 $^{\circ}C$ higher than the design temperature it makes the life of the chip shorten more than 50%. Therefore, it is required that we solve the problem of heating value and make the efficiency of e-MMC improved. In this study, geometry of 16-multilayered structure is compared the temperature distribution of four different geometries along the numerical analysis. As a result, it is con finned that a multilayer structure of stair type is more efficient than a multilayer structure of vertical type because a multi-layer structure of stair type is about 9 $^{\circ}C$ lower than a multilayer structure of vertical type.