• Clean Technology
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• v.20 no.3
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• pp.290-297
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• 2014

Batch adsorption studies were carried out for equilibrium, kinetics and thermodynamic parameters for adsorption of coomassi brilliant blue G (CBBG) using activated carbon with varying the operating variables like initial concentration, contact time and temperature. Equilibrium adsorption data were fitted into Langmuir, Freundlich and Dubinin-Radushkevich isotherms. From estimated separation factor of Langmuir and Freundlich, this process could be employed as effective treatment for removal of CBBG. Also from Dubinin-Radushkevich isotherm model, adsorption energy (E) indicated adsorption process is physical adsorption. From kinetic experiments, the adsorption reaction was found to confirm to the pseudo second order model with good correlation. Intraparticle diffusion was rate controlling step. Thermodynamic parameters like change of free energy, enthalpy, and entropy were also calculated to predict the nature of adsorption. The change of enthalpy (406.12 kJ/mol) indicated endothermic nature of the adsorption process. The change of entropy (1.66 kJ/mol K) showed increasing disorder in process. The change of free energy found that the spontaneity of process increased with increasing adsorption temperature.

• Asian-Australasian Journal of Animal Sciences
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• v.29 no.11
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• pp.1593-1600
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• 2016

This research was conducted to investigate the physiological consequences of undernourished yak. Twelve Maiwa yak ($110.3{\pm}5.85kg$) were randomly divided into two groups (baseline and starvation group). The yak of baseline group were slaughtered at day 0, while the other group of yak were kept in shed without feed but allowed free access to water, salt and free movement for 9 days. Blood samples of the starvation group were collected on day 0, 1, 2, 3, 5, 7, 9 and the starved yak were slaughtered after the final blood sample collection. The liver and muscle glycogen of the starvation group decreased (p<0.01), and the lipid content also decreased while the content of moisture and ash increased (p<0.05) both in Longissimus dorsi and liver compared with the baseline group. The plasma insulin and glucose of the starved yak decreased at first and then kept stable but at a relatively lower level during the following days (p<0.01). On the contrary, the non-esterified fatty acids was increased (p<0.01). Beyond our expectation, the ketone bodies of ${\beta}$-hydroxybutyric acid and acetoacetic acid decreased with prolonged starvation (p<0.01). Furthermore, the mRNA expression of lipogenetic enzyme fatty acid synthase and lipoprotein lipase in subcutaneous adipose tissue of starved yak were down-regulated (p<0.01), whereas the mRNA expression of lipolytic enzyme carnitine palmitoyltransferase-1 and hormone sensitive lipase were up-regulated (p<0.01) after 9 days of starvation. The phosphoenolpyruvate carboxykinase and pyruvate carboxylase, responsible for hepatic gluconeogenesis were up-regulated (p<0.01). It was concluded that yak derive energy by gluconeogenesis promotion and fat storage mobilization during starvation but without ketone body accumulation in the plasma.

• Korean Journal of Materials Research
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• v.26 no.11
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• pp.649-655
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• 2016

Ni nanoparticles (NPs)-graphitic carbon nanofiber (GCNF) composites were fabricated using an electrospinning method. The amounts of Ni precursor used as catalyst for the catalytic graphitization were controlled at 0, 2, 5, and 8 wt% to improve the photovoltaic performances of the nanoparticles and make them suitable for use as counter electrodes for dye-sensitized solar cells (DSSCs). As a result, Ni NPs-GCNF composites that were fabricated with 8 wt% Ni precursors showed a high circuit voltage (0.73 V), high photocurrent density ($14.26mA/cm^2$), and superb power-conversion efficiency (6.72%) when compared to those characteristics of other samples. These performance improvements can be attributed to the reduced charge transport resistance that results from the synergetic effect of the superior catalytic activity of Ni NPs and the efficient charge transfer due to the formation of GCNF with high electrical conductivity. Thus, Ni NPs-GCNF composites may be used as promising counter electrodes in DSSCs.

• Journal of the Korean Electrochemical Society
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• v.8 no.1
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• pp.1-5
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• 2005

Electric double layer capacitors(EDLCS) based on the charge stored at the interface between a hi팀 surface area carbon electrode and an organic electrolyte solution are widely used as a maintenance-free power source for IC memories and microcomputers. The achievement of the excellent performance of the capacitor requires an electrolyte solution which provides high conductivities over a wide temperature range and good electrochemical stabilities to allow the capacitor to be operated at high voltage. The electrochemical capacitor using a carbon material as electrodes and using an organic electrolyte with $1M-LiPF_6$ in PC-GBL-DEC(volume ratio 1:1:2) has specific capacitance of 64F/g.

• Advances in nano research
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• v.13 no.3
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• pp.207-216
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• 2022

In this paper, a novel model is developed for frequency behavior of single walled carbon nanotubes. The governing equation of motion is constructed method based on the Sander theory using Rayleigh-Ritz's method The frequencies enhances on increasing the power law index using simply supported, clamped and clamped free end conditions. The frequency curve for C-F is less than other conditions. It is due to the physical constraints which are applied on the edge of the CNT. It is observed that the C-F boundary condition have less frequencies from the other two conditions. The frequency phenomena for zigzag are insignificant throughout the aspect ratio. Moreover when index of power law is increased then frequencies increases for all boundary conditions. The natural frequency mechanism for the armchair (10, 10) for various values of power law index with different boundary conditions is investigated. Here frequencies decrease on increases the aspect ratio for all boundary conditions. The frequency curves of SS-SS edge condition is composed between the C-C and C-F conditions. The curves of frequency are less significant from small aspect ratio (L/d = 4.86 ~ 8.47) and decreases fast for greater ratios. It is found that the frequencies via aspect ratios, armchair (10, 10) have higher values from zigzag (10, 0). It is due to the material structure which is made by the carbon nanotubes. The power law index have momentous effect on the vibration of single walled carbon nanotubes. The present frequency result is also compared numerically experimentally with Raman Spectroscopy.

• Journal of the Korean Society of Tobacco Science
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• v.29 no.2
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• pp.90-97
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• 2007

This study was conducted to evaluate the effect of additives (antioxidants for free radicals reduction) in cigarette filter treated with various antioxidants (three types of proanthocyanidins and ascorbic acid) and various concentrations of ascorbic acid and loaded with activated carbon on the delivery of free radicals of mainstream smoke (MS) by ESR. Also, we analyzed Hoffmann's analytes andscavenger activity according to the storage time and in vitro cytotoxicity. The analysis of spin number of vapor and particulate phase free radicals in MS are decreased to $14{\sim}24\;%$ and $16{\sim}40\;%$, respectively. As aresult of antioxidant potential for inactivity of vapor and particulate phase free radicals, natural antioxidants were more effective than ascorbic acid. Based on the result of the analysis of Hoffmann's analytes for various antioxidantstreated cigarette filters during the smoking, cigarette filter treated with ascorbic acid showed the lower amount of the deliveries of hydroquinone, isoprene and quinoline in MS than those treated with the other antioxidants. In the significant t-test on the difference of the cytotoxicity among the various antioxidants treated-cigarette filters, there are no significant differences at the 95 % confidence level. Those results indicated that the antioxidants were useful for reducing free radicals in MS because of the fast reaction between antioxidant and free radicals.

• Journal of Energy Engineering
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• v.26 no.1
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• pp.1-8
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• 2017

This study was carried out to physicochemical properties and free CaO contents of coal ash in domestic circulating fludized bed combustion power plant using ethylene glycol method. Results of physicochemical properties, there are many differences in CaO contents for the region position in CFBC plant. The reason, It is considered to be reflected that regulation of exhaust concentration for oxides of sulfur and other operation characteristics of region position in CFBC plant. Free CaO contents are 1.96 ~ 10.78% of fly ash and 0.07~4.24 % of bottom ash, fly ash is higher than in the bottom ash. besides CaO contents of raw materials, particle distribution have a lot of influence Free CaO contents.

• Applied Biological Chemistry
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• v.43 no.2
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• pp.95-99
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• 2000

A series of hetero ring (X) substitued chalcone derivatives with farnesyl protein transferase (FPTase) inhibition activities $(pI_{50})$ values determined in vitro is analyzed by modified Free-Wilson (F-W) and Hansch method for quantitative structure activity relationship (QSARs). On the basis of F-W analysis on the FPTase inhibitory activity of a training set of the compounds, none of the (X)-substituents were not contribute the activity. But the net charge of ${\alpha}$ carbon atom is contribute the activity than that of ${\beta}$ carbon atom. And the relative orders of the (Y)-substituents on the activity are ortho>meta>para-substituents. According to Hansch approach, the activities would depend largely on the optimal, $(R_{opt.}=-0.35)$ resonance effect with ortho substituted $(I_o>0)$ electron donating group (R<0) and STERIMOL parameter, $B_1$ constant. The inhibition activity between hetro ring substituents have been a proportioned with each others and none substituent(H), 45 showed the highest FPTase inhibition $(pI_{50}=4.30)$ activity.

• Korean Chemical Engineering Research
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• v.53 no.1
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• pp.83-90
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• 2015

In this study, we investigated optimum conditions for the introduction of a lot of free radical polymerizable methacrylate groups on the multi-walled carbon nanotube (MWCNT) surface. Carboxyl groups were introduced first on MWCNT surfaces by treating with a mixture of sulfuric acid and nitric acid with ultrasonic bath for 2 hours, and oxidized MWCNTs were reacted further with thionyl chloride followed by triethylenetetramine (TETA) to introduce amino groups on the oxidized MWCNT surface, to make MWCNT-$NH_2$. To introduce free radical polymerizable methacrylate groups on the MWCNT-$NH_2$, MWCNT-$NH_2$ was reacted with 3-(acryloyloxy)-2-hydroxypropyl methacrylate (AHM) by Michael addition reaction. We investigated progress of modification reactions for MWCNT by fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA) and elemental analysis (EA). We found maximum degree of Michael addition reactions between AHM and TETA grafted on MWCNT-$NH_2$ for 10:1 mol ratio and 8 hour reaction time in our reaction conditions.

• Proceedings of the Korean Vacuum Society Conference
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• 1999.07a
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• pp.135-135
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• 1999

It is well known that Raman spectroscopy is powerful tool in analysis of sp3/sp3 bonding fraction in diamond-like carbon(DLC) films. Raman spectra of DLC film is composed of D-peak centered at 1350cm-1 and G-peak centered at 1530cm-1. The sp3/sp3 fraction is qualitatively acquired by deconvolution method. However, in case of DLC film, it is generally observed that G-peak position shifts toward low wavenumber as th sp3 fraction increases. However, opposite results were frequently observed in ta-C films. ta-C film has much higher residual compressive stress due to its high sp3 fraction compared to the DLC films deposited by CVD method. Effect of residual stress on G-peak position is most recommendable parameter in Raman analysis of ta-C, due to its smallest fitting error among many parameters acquired by peak deconvolution of symmetric spectra. In current study, the effect of residual stress on Raman spectra was quantitatively evaluated by free-hang method. ta-C films of different residual stress were deposited on Si-wafer by modifying DC-bias voltage during deposition. The variation of the G-peak position along the etching depth were observed in the free-hangs of 20~30${\mu}{\textrm}{m}$ etching depth. Mathematical result based on Airy stress function, was compared with experimental results. The more reliable analysis excluding stress-induced shift was possible by elimination of the Raman shift due to residual compressiove stress.