• Journal of the Korean Ceramic Society
• /
• v.45 no.11
• /
• pp.667-674
• /
• 2008

In this study, we prepared Fe-activated carbon fiber(ACF)/$TiO_2$ composites with titanium (VI) n-butoxide (TNB) as the titanium source for ACF pre-treated with iron compounds through the impregnation method. In terms of textural surface properties, the composites demonstrate a slight decrease in the BET surface area of the samples and an increase in the amount of iron compounds treated. The surface morphology of the Fe-ACF/$TiO_2$ composites was characterized by means of SEM. The composites have a porous texture with homogenous compositions of Fe and titanium dioxide distributed on the sample surfaces. The phase formation and structural transition of the iron compounds and titanium dioxide were observed in X-ray diffraction patterns of the Fe-ACF/$TiO_2$ composites. The chemical composition of the Fe-ACF/$TiO_2$ composites, which was investigated with EDX shows strong peaks for the C, O, Fe and Ti elements. The photo degradation results confirm that the Fe-ACF/$TiO_2$ composites show excellent removal activity for the COD in piggery waste due to photocatalysis of the supported $TiO_2$, radical reaction by Fe species, and the adsorptivity and absorptivity of ACF.

• Elastomers and Composites
• /
• v.33 no.3
• /
• pp.201-209
• /
• 1998

Alumina powders used as a filler in rubber compounding was extracted from kaolin in $H_2SO_4$ solution employing conventional thermal and microwave energy resources. Maximum degrees of alumina extraction from kaolin were 72.8% at $80^{\circ}C$, 1M $H_2SO_4$, and 180min in the conventional thermal extraction process and were 99.0% at $90^{\circ}C$, 1M $H_2SO_4$,, and 60min in the microwave extraction one, respectively. The samples synthesized in both processes were analyzed by means of TG/DTA, XRD, SEM, Atomic Emission Spectroscopy, and BET method. Studies are presently under way to unravel the basic interaction mechanisms between microwave and alumina power for high rates of alumina extraction from kaolin in the microwave ex-traction process.

• YAKHAK HOEJI
• /
• v.29 no.4
• /
• pp.176-182
• /
• 1985

As a part of the studies on adsorptive properties of Korean halloysite clays, Hadong white clays of premium grade were examined for geometric pore structured by mercury porosimetry and for specific surface areas by nitrogen adsorption according to the BET procedure. Three size fractions of the native clay sample were derived from passage BS #100, #200 and #325 meshes, respectively. Several parameters lhus observed in relation to the pore structures are shown below: 1. The size fraction of BS #100, #200 and #325 show internal pore volumes of 25.3, 30.2 and $35.0m^2g^{-1}$, respectively. 2. In the distribution curves of the cumulative pore volume against pore diameter, it has been shown that the larticle sizes, the steeper the distribution over the larger ranges of pore diameters. The converse is true the smaller particles. 3. Internal pore areas increase with decrease in pore sizes. It follows that the pores having diameters of $\leq$0.1$\mu\textrm{m}$ are responsible for more than 90% of the total pore area. 4. The behaviour of nitrogen adsorption can be best described by BET type IV isotherm. Further, the hysteresis loops of the adsorptiondesorption curves become narrower with decresing particle sizes. 5. The specific surface areas observed for the fractions of BS #100, BS #200 and BS #325 are 34.6, 35.4 and 43.2m $^2g^{-1}$, respectively. and the calcined clay of BS #325 has a specific surface area near $30.4m^2g^{-1}$.

• YAKHAK HOEJI
• /
• v.33 no.2
• /
• pp.111-117
• /
• 1989

The optimum reaction conditions for the acid consuming capacity of aluminum silicate synthesized from the reaction of sodium silicate solution and potassium aluminum sulfate solution were investigated by Box-Wilson experimental design, and the micromeritic properties were examined by the means of BET $N_2$ adsorption, Hg penetrometer and methylen blue adsorption. The chemical composition of the samples were analyzed by gravitic method. The results were found to be as follows: optimum reaction temperature $54.7^{\circ}C$, both concentrations of reactant soln 15.7%, reactants molar ratio (Al/Si) 0.5 and drying temperature $65.0^{\circ}C$. The acid consuming capacity of the sample prepared by above optimum conditions was 68 ml and the chemical composition was $Al_2O_3{\cdot}3.6SiO_2{\cdot}3H_2O$. The relationship between acid consuming capacity and micromeritic properties could not found in the range of experiments. Therefore, it is assumed that the acid consuming mechanism of aluminum silicate depends on the neutralization of $Al_2O_3$ and buffer action of $SiO_2$ in sample.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.13 no.2
• /
• pp.215-221
• /
• 1984

To investigate stability for the quality of selected ginseng products, their sorption properties were clarified in red ginseng extract(RGEP), and red ginseng extract powder(RGEP), and red ginseng extract tea(RGET). Simultaneously, the BET monolayer value of each product was determined in order to inquire out the possibility of establishment as a criterion for the optimum moisture content of the ginseng products. Based on the BET monolayer moisture level of spray dried RGEP which ranged from 4.08 to 4.65%, it would be desirable to establish the optimum moisture content of the products at 4.4${\pm}$0.3%. This is 1.3 to 1.9% lower than the criter on, "less than 6.0%". The optimum moisture level for RGET of which monolayer value ranged 0.93 to 1.37% would be 1.2${\pm}$0.17%. In this case, the maximum permissible limit of moisture content could presumably be raised up to 1.37% in place of current criterion, "less than l.2%". From the results of a study on the growth of molds, the optimum moisture content for RGE assumed to be extended up to 40.0${\pm}$1.07 despite 36.0${\pm}$1.0% of the present criterion. On the other hand, a storage study under the maltreated condition, $48{\pm}2^{\circ}C$ 75%RH, was also carried out in order to make it clear whether the BET monolayer values were able to be used as indices for optimum moisture level of the products. In all samples tested adsorption occurred at even higher levels of moisture than the monolayer values. However, since there are many other possible factors affecting the quality of products the optimum moisture content is preferable to be reduced to the monolayer value. As a result, it was proved that the optimum level of moisture for both RGEP and RGET could be established by the monolayer values.

• Reproductive and Developmental Biology
• /
• v.29 no.3
• /
• pp.163-168
• /
• 2005

The aim of this study was to investigate the changes in insulin-like growth factor-I (IGF-I) and growth hormone (GH) in serum, the quantitation of spermato-genesis and the comparable relationships among these measurements during pubertal period in New Zealand White male rabbits. To investigate the age-related testicular changes in DNA contents of spermatogenic cells, the fine-needle testicular biopsies from males aged 10 to 28 wks were evaluated by flow cytometry(FCM). Body weight increased significantly between the ages of 12 and 20 wks (P<0.05) and reached 3.4 kg at 28 wks of age. The highest serum IGF-I level (451.3ng/mL) was observed at 20wks of age (P<0.05) and thereafter remained stable at low levels. Serum GH level at 18 wks of age was 183.3 pg/mL which was significantly higher compared to the other ages (P<0.05), and the rising time in serum GH tend to be somewhat earlier than that of IGF-I. The relative percentage of It-cells in testicular cell compartments was $48.2\%$ at the age of 18 wks which significantly increased than those of 16-wk-old (P<0.05) and thereafter increased with the advance of age to $68\%$. The percentage of 2C-cells in testis was $26.8\%$ at 18 wks of age which was significantly lower than $54.3\%$ at 16 wks old (P<0.05). The percentage of 4C-cells was constantly maintained $2\~6\%$ except the $9.9\%$ at 18 wks of age. In conclusion, the results suggest that the puberty onset occurred at about the 18 wks of age and that the IGF-I and GH in serum during the pubertal period showed the age/growth-specific changes and these changes might be related to the spermatogenesis. The DNA FCM combined with fine-needle testicular biopsy could offer a very sensitive method to monitor the quantitative spermatogenic events related to the puberty onset.

• Clinical and Experimental Reproductive Medicine
• /
• v.44 no.4
• /
• pp.214-223
• /
• 2017

Objective: In vitro fertilization (IVF) is a well-known method for the treatment of infertility. The present study aimed to compare the differences between infertile women with successful and unsuccessful IVF outcomes regarding the expression of T helper (Th) cell transcription factors and a group of related cytokines before and after exposure to their husbands' seminal plasma. Methods: This study was performed on 19 couples with unexplained infertility undergoing IVF treatment. Among the studied group, nine and 10 couples had successful and unsuccessful IVF outcomes, respectively. This study was carried out using real-time polymerase chain reaction. Results: Before seminal plasma exposure, the expression levels of T-bet (p< 0.007), $interferon-{\gamma}$ (p= 0.013), and tumor necrosis factor $(TNF)-{\alpha}$ (p= 0.017) were higher in the infertile women with IVF failure than in those with successful IVF outcomes, while those of GATA3 (p< 0.001), Foxp3 (p= 0.001), and interleukin (IL)-35 (p< 0.003) were lower. After seminal exposure, the expression of T-bet (p= 0.02), Rorc (p< 0.001), $TNF-{\alpha}$ (p= 0.001), Foxp3 (p= 0.02), and $interferon-{\gamma}$ (p= 0.001) increased in the unsuccessful IVF group, while the expression of Foxp3 (p= 0.02), Rorc (p< 0.001), IL-23 (p= 0.04), IL-17 (p= 0.02), IL-6 (p< 0.001), transforming growth $factor-{\beta}$ (p= 0.01), and IL-35 (p< 0.001) increased in the successful IVF group. Conclusion: In summary, IVF failure was associated with imbalanced Th1/Th2/Th17/Treg responses. Moreover, our results show that seminal plasma might have a positive effect on IVF outcomes via changes in peripheral blood T cell subsets.

• Analytical Science and Technology
• /
• v.12 no.2
• /
• pp.105-110
• /
• 1999

The studies on the adsorption properties and the antibacterial effects of the Cd and Cu-treated activated carbon were carried out. From the adsorption studies on the series of these metal-treated activated carbons, typical Type-I isotherm was observed. The surface areas of the treated carbon obtained from BET equation were in the range of $1101-1418m^2/g$ for Cd-AC and of $1084-1361m^2/g$ for Cu-AC. Using ${\alpha}_s$-plot, the micropore volumes and pore size distribution were obtained. From the SEM study, it is also observed that many of micropores in activated carbon are blocked by window blocking effect of metals after the impregnation. Finally, antibacterial effects of M-activated carbon against Escherichia coli was discussed. From the study, the area of antibacterial activity becomes larger with the increase of the amount of metal treated.

• Korean Chemical Engineering Research
• /
• v.50 no.3
• /
• pp.551-555
• /
• 2012

Desorption reaction characteristics of the commercial activated carbons which were used for the removal of industrial odorants were investigated. BET specific surface area was analyzed to investigate the chemicophysical property of activated carbon. Adsorptivity of activated carbon was estimated by iodine number. Thermogravimetric analyzer (TGA) was used to investigate the desorption characteristics. Activation energies and reaction orders for reaction characteristics according to adsorption and desorption of activated carbons were estimated by employing the Friedman method and Freeman-Carroll method. Adsorptivity of reprocessed activated carbons were significantly lower than that of fresh activated carbons. In this study, it was found that the activation energies were 15.9~23.4 kJ/mol in Friedman method and 22.7~33.8 kJ/mol in Freeman-Carroll method.

• Macromolecular Research
• /
• v.16 no.6
• /
• pp.492-502
• /
• 2008

This study examined the adsorption of a synthetic cutting fluid and cutting fluid effluent on chitosan and SDS-modified chitosan, Chitosan and SDS-modified chitosan were prepared in form of beads and fibers. A series of batch experiments were carried out as a function of the initial concentration of cutting fluid, contact time and pH of the fluid. The contact angle study suggested that the SDS-modified chitosan was more hydrophobic than chitosan. The Zeta potential study showed that chitosan, SDS-modified chitosan and synthetic cutting fluid had a point of zero charge (PZC) at pH 7.8, 9 and 3.2, respectively. SDS-modified chitosan has a greater adsorption capacity than chitosan. The experimental results show that adsorption capacity of the cutting fluid on 1.0 g of SDS-modified chitosan at pH 3 and for a contact time of 120 min was approximately 2,500 g/kg. The adsorption capacity of chitosan and SDS-modified chitosan increased with decreasing pH. The Langmuir, Freundlich, and Brunauer Emmett and Teller (BET) adsorption models were used to explain the adsorption isotherm. The Langmuir isotherm fitted well with the experimental data of chitosan while the BET isotherm fitted well with the SDS-modified chitosan data. Pseudo first- and second-order kinetic models and intraparticle diffusion model were used to examine the kinetic data. The experimental data was fitted well to a pseudo second-order kinetic model. The significant uptake of cutting fluid on chitosan and SDS-modified chitosan were demonstrated by FT-IR spectroscopy, SEM and heat of combustion.