• Korean Journal of Environmental Agriculture
• /
• v.29 no.3
• /
• pp.273-281
• /
• 2010

Concentration of antibiotics including a tetracycline group (TCs) of tetracycline (TC), chlortetracycline (CTC), and oxytetracycline (OTC), a sulfonamide group (SAs) of sulfamethoxazole (SMX), sulfathiazole (STZ), and sulfamethazine (SMT), an ionophore group (IPs) of lasalocid (LSL), monensin (MNS), and salinomycin (SLM), and a macrolide group (MLs) of tylosin (TYL) was determined from samples collected from the agricultural soil, stream water, and sediment. For the agricultural soil samples, the concentration of TCs had the highest value among all tested antibiotic's groups due to its high accumulation rate on the surface soils. The lower concentrations of SAs in the agricultural soils may be resulted from its lower usage and lower distribution coefficient (Kd) compared to TCs. The concentration of TCs in stream water was significantly increased through June to September. It would be likely due to soil loss during an intensive rainfall event and a reduction of water level after the monsoon season. A significant amount of TCs in the sediment was also detected due to its accumulation from runoff, which occurred by complexation of divalent cations, ion exchange, and hydrogen bonding among humic acid molecules. To ensure environmental or human safety, continuous monitoring of antibiotics residues in surrounding ecosystems and systematic approach to the occurrence mechanism of antibiotic resistant bacteria are required.

• Food Science of Animal Resources
• /
• v.31 no.3
• /
• pp.460-468
• /
• 2011

We evaluated the effect of adding mechanically deboned chicken meat (MDCM) (0, 10, 20, 30 or 50%) on quality characteristics of chicken sausage. Adding MDCM decreased the protein content of chicken sausage, but ash content increased significantly. Adding MDCM had no effect on pH and water holding capacity of sausage. Adding MDCM increased cooking loss, but did not affect the shear force value of the sausage. Adding MDCM decreased the L- (lightness) and b- (yellowness) values but increased the a- (redness) value of sausage. Adding MDCM decreased the hardness and cohesiveness values, but did not affect the springiness value of chicken sausage. Adding MDCM decreased the juiciness and hardness but increased the flavor and chewiness scores of chicken sausage. Regardless of the MDCM addition level, all chicken sausage contained low residual nitrite ion (<4 ppm). During the 10 d of storage at $4^{\circ}C$, adding MDCM did not affect total microbial count or TBA values of chicken sausage, but the VBN value of the sausage increased slightly. However, all storage characteristic values in the sausage were within the safety range. Adding MDCM (0, 10 or 20%) to chicken sausage resulted in a finely structured protein matrix under scanning electron microscopy (SEM), which indicated a good meat emulsion, but adding MDCM at more than 20% resulted in a very coarse protein matrix structure.

• Journal of Energy Engineering
• /
• v.25 no.3
• /
• pp.66-72
• /
• 2016

In this study, a sulfonated poly(arylene ether ketone) block copolymer was prepared from hydrophilic oligomer and hydrophobic oligomer. The structure of the prepared membrane was characterized by $^1H$-NMR, FT-IR and GPC. The $M_w$(weight-average molecular weights) of the polymer was $209,700g\;mol^{-1}$ and the molecular weight distribution($M_w/M_n$) of 1.25 was obtained. The prepared membrane showed excellent thermal stability with gradual weight loss up to $200^{\circ}C$. The proton conductivity of SPAEK block copolymer reached the maximum of $9.0mS\;cm^{-1}$ at $90^{\circ}C$ under 100% relative humidity (RH). From the observed results, it is necessary to do more aggressive attempt to study the possibility of application as an ion-conductive composite electrolyte.

• Economic and Environmental Geology
• /
• v.25 no.1
• /
• pp.27-39
• /
• 1992

Several pyrophyllite deposits occur around the Milyang area where Cretaceous andesitic rocks and spatially related granitic rocks are widely distributed. Pyrophyllite ores consist mainly of pyrophyllite, and quartz with small amount of sericite, pyrite, dumortierite, and diaspore. The andesitic rocks and spatially related granitic rocks in this area suggest that they could be formed from the same series of a calc-alkaline magma series. The contents of $SiO_2$, $Al_2O_3$, LOI(loss on ignition) are enriched, and $K_2O$, $Na_2O$, CaO, MgO, $Fe_2O_3$ are depleted in altered andesitic rocks and ores. Enrichment of As, Cr, Sr, V, Sb and depletion of Ba, Cs, Ni, Rb, U, Y, Co, Sc, Zn are characteristic during mineralization. The pyrophyllite ores can be discriminated from the altered-and unaltered wall-rocks by an increasing of $(La/Lu)_{cn}$ from 4.18~22.13 to 8.98~55.05. In R-mode cluster analysis, Yb-Lu-Y, La-Ce-Hf-Th-U-Zr, $TiO_2-V-Al_2O_3$, Sm-Eu, $CaO-Na_2O-MnO$, Cu-Zn-Ag, $K_2O-Rb$ are closely correlated. In the discriminant analysis of multi-element data, $P_2O_5$, As, Cr and $Fe_2O_3$, Sr are helpful to identify the ores from the unaltered-and altered wall-rocks. In the factor analysis, the factors of alteration of andesitic rocks and ore mineralization were extracted. In the change of ions per unit volume, $SiO_2$, $Al^{3+}$ and LOI are enriched and $Na^+$, $K^+$, $Ca^{2+}$, $Mg^{2+}$, $Mn^{2+}$ and $Fe^{3+}$ are depleted during the alteration processes. The Milyang and the Sungjin pyrophyllite deposits could be mineralized by hydrothermal alteration in a geochemical condition of low activity ratio of alkaline ions to hydrogen ion with reference to spatially related granitic rocks.

• Applied Chemistry for Engineering
• /
• v.31 no.5
• /
• pp.575-580
• /
• 2020

In this study, we simulated an amine regeneration process with heat-stable salts removal unit. We derived the optimal operating conditions considering the flow rate of waste, the removal rate of heat-stable salts, and the loss rate of MDEA (methyl diethanolamine). In the amine regeneration process that absorbs and removes acid gas, heat-stable salt impairs the absorption efficiency of process equipment and amine solution. An ion exchange resin method is to remove heat-stable salts through neutralization by using a strong base solution such as NaOH. The acid gas removal process was established using the Radfrac model, and the equilibrium constant of the reaction was calculated using Gibbs free energy. The removed amine solution is separated and flows to the heat-stable salts remover which is modeled by using the Rstoic model with neutralization reaction. Actual operation data and simulation results were compared and verified, and also a case study was conducted by adjusting the inflow mass of removal unit followed by suggesting optimal conditions.

• Journal of Hydrogen and New Energy
• /
• v.13 no.2
• /
• pp.143-150
• /
• 2002

The thermal behavior of $(Co_{0.5}\;Mn_{0.5})Fe_2O_4$ prepared by a co-precipitation wasinvestigated for Hz generation by the thermochemical cycle. The reduction reaction of $(Co_{0.5}\;Mn_{0.5})Fe_2O_4$ started from $480^{\circ}C$, and the weight loss was 1.6 wt% up to $1100^{\circ}C$. At this reaction, $(Co_{0.5}\;Mn_{0.5})Fe_2O_4$ was reduced by release of oxygen bonded with the $Fe^{3+}$ ion in the B site of ($CO_{0.5}$ $(Co_{0.5}\;Mn_{0.5})Fe_2O_4$. In the $H_2O$ decomposition reaction, $H_2$ was generated by oxidationof reduced $(Co_{0.5}\;Mn_{0.5})Fe_2O_4$. The crystal structure of $(Co_{0.5}\;Mn_{0.5})Fe_2O_4$ for reduction reaction maintained spinel structure and the lattice constant of $(Co_{0.5}\;Mn_{0.5})Fe_2O_4$ ($8.41\AA$) was enlarged to $8.45\AA$. But the lattice constant of $(Co_{0.5}\;Mn_{0.5})Fe_2O_4$ after $H_2O$ decomposition reaction did not change to $8.45\AA$. Then, $(Co_{0.5}\;Mn_{0.5})Fe_2O_4$ is excellent material in the thermochemical cyclic reaction due to release oxygen at low temperature for the reduction reaction and produce $H_2$ maintaining crystal structure for redox reaction.

• Korean Journal of Microbiology
• /
• v.41 no.1
• /
• pp.81-86
• /
• 2005

One of the endoglucanases, F-I-III, was purified from the culture filtrate of T. sp. C-4 through procedures including chromatography on Sephacryl S-200, DEAE-Sepharose A-50, and Chromatofocusing on Mono-P (FPLC). The molecular weight of the enzyme was determined to be about 56,000 Da by SDS-PAGE, and pI of 4.9 by analytical isoelectric focusing. F-I-III showed the highest enzyme activity at $55^{\circ}C$, and the pH optimum of the enzyme was 5.0. There was no loss of activity when the enzyme was incubated at $50^{\circ}C$ for 24 hours. The specific activity of the enzyme F-I-III toward the CMC was 315.4 U/mg. The Km value for $PNPG_2$ of F-I-III was 2.69 mM. N-terminal sequence of F-I-III was analyzed to be QPGTSTPEVHPKKLTTYK. It showed $95\%$ of homology to that of EGI from T. reesei. The presence of some metal ions (1 mM) had only a little effect on CMCase activity. The treatment of the reducing agents resulted in the increase of endoglucanase activity.

• Journal of the Korean Chemical Society
• /
• v.55 no.4
• /
• pp.603-611
• /
• 2011

Ethoxylacetyl oxime ligands [HL, (1) and $H_2L^1$, (3)] react with copper(II) acetate monohydrate yield octahedral and square planar complexes, respectively. The complexes have been postulated due to elemental analyses, IR, UVVis. spectra, magnetic susceptibility, conductivity and ESR spectra. Molar conductance of the complexes in DMF indicates a non-ionic character. The ESR spectra of [$(L)_2Cu(H_2O)_2$], (2) complex at room temperature and 77K are characteristic of an axial symmetry ($d_{x2-y2}$) with covalent bond character and have a large line width typical of dipolar interactions. However, [$(L^1)Cu$], (4) complex in the solid state showed spectra of marked broadening and loss of hyperfine splitting confirming spinexchange interactions between the copper(II) sites. The spectrum of the doped copper(II) complex at room temperature showed super-hyperfine splitting from coordinated nitrogen atoms and it has an axial type ($d_{x2-y2}$) with covalent bond character and an essentially square-planar arrangement around the copper(II) ion. The spectrum of [$(L^1)Cu$], (4) in frozen methanol at 77K was characteristic of the triplet state of a dimer species and the distance found between the two copper(II) centers was calculated and is equal to 4.8 ${\AA}$.

• Korean Journal of Agricultural Science
• /
• v.29 no.1
• /
• pp.44-54
• /
• 2002

The fresh eggs of African ostrich in Korea were used in this study to investigate their interior and exterior quality characteristics. In ostrich egg shape characteristics, long and short length were measured as 15.1~16.1 cm and 12.1~13.6 cm, respectively. The egg shape index was calculated as 81.0 and the egg shell showed a more g loss white in color than that of hen egg. Calculated breaking strength of egg shell and egg shell surface based on the equation were $41.155kg/cm^3$ and $804.7cm^2$, respectively. Average egg shell thickness including egg shell membrane was 1.89 mm and there are no differences among parts of the shell. The egg shell membrane thickness was 0.10 mm showing relatively thick in equator compared with that of blunt end. The ave rage number of egg shell pores was counted as $19.7/cm^2$ showing relatively high number of egg shell pores at point end and the total number of egg shell pores in an egg was estimated as 15,241. The relative port ion of each parts based on egg weight was estimated as 25.1% for egg yolk, 58.2% for egg white, 16.7% for egg shell and the ratio of egg yolk to egg white (Y/W) was 0.43. The average diameter and the ave rage height of ostrich egg white were 19.7 cm and 13.2 mm, respectively. Calculated the H.U (Haugh Unit) was -69.7 and the pH was 8.3. In ostrich egg yolk, the diameter, the height, the egg yolk index, and it's pH were calculated as 14.4 cm, 29.4 mm, 0.20, and 6.6, respectively. And the egg yolk color showed a more thin in yellow chroma compared with that of hen egg as due to it's thicker membrane.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.26 no.2
• /
• pp.147-156
• /
• 1981

Most of the currently available rice threshers in Korea are of head-feeding type originally developed for threshing paddy at grain moisture content of 15 to 17% on wet basis. And prevailing rice harvesting system is swathing or cutting and bundling upright rice crop at a maturity stage of grain moisture content of ca. 28 to 20%, followed by transient natural drying in the field and threshing at grain moisture content of about 17%. The system often allows rather high field loss of rice both quantitatively and qualitatively. These necessitate use of a preharvest desiccant, and diquat has been registered recently as a rice desiccant. Aim of the present study is to determine the best time and rate of diquat application and to evaluate its utility as a rice desiccant under its optimal usage conditions in Korea. Diquat was not so effective for japonica rice varieties while it was very effective for the new varieties bred from indica x japonica crosses. The best time of application was the period from 2 days before to 3 days after physiological maturity of grain (moisture content of 28% w.b.) and the optimal rate was about 330g of diquat ion/ha. Applying diquat at the right time and rate dropped grain moisture to 15 to 16% (w.b.) within a week after treatment in contrast to that of 20 to 24% in untreated rice. Desiccation of rice crop with diquat resulted in 10 to 15% increase in grain resistance to shattering and significant reduction in percent green rice. However, there was no reduction in milled rice yield and percent whole kernel and was no change in the percent chalky rice and percent tinted rice. Diquat use appears highly desirable, if there is no residue problem which has not been studied in the present study.