• Applied Chemistry for Engineering
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• v.3 no.3
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• pp.499-506
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• 1992

Copolymer of Styrene and GMA(glycidyl methachylate), having reactive ratios of $r_1=0.53$, $r_2=0.44$, was synthesized in dioxane using AIBN as free radical initiator. Followed by the reaction of ethylene diamine with copolymer PGS, amine groups were introduced to the PGS(NPGS). The composition of copolymer was determined by elemental analyzer. Poly(glycidyl methacrylate) (PGMA) was obtained in benzene using AIBN as free radical initiator. The NPGS-PGMA blend of 50/50 composition was prepared by mixing these polymers in THF at $65^{\circ}C$. Glass transition temperature (Tg) of NPGS-PGMA blend was measured by DSC. The blend showed a single Tg. Accordingly, it was clear that the NPGS was compatible with PGMA. An intermolecular reaction between amine groups of NPGS and epoxy groups of PGMA imparts compatibility in the NPGS-PGMA blend. When the NPGS-PGMA blend was added to the incompatible PS-PGMA blend, PS-PGMA blend showed Tg change. Scanning Electron Micrograph(SEM) showed a fine morphology in this blend. Consequently, it was apparent that the NPGS-PGMA blend acted as a compatibilizer for the PS-PGMA blend.

• Journal of Environmental Science International
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• v.26 no.5
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• pp.601-608
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• 2017

The effects of elevated atmospheric $CO_2$ on growth and photosynthesis of soybean (Glycine max Merr.) were investigated to predict its productivity under elevated $CO_2$ levels in the future. Soybean grown for 6 weeks showed significant increase in vegetative growth, based on plant height, leaf characteristics (area, length, and width), and the SPAD-502 chlorophyll meter value (SPAD value) under elevated $CO_2$ conditions ($800{\mu}mol/mol$) compared to ambient $CO_2$ conditions ($400{\mu}mol/mol$). Under elevated $CO_2$ conditions, the photosynthetic rate (A) increased although photosystem II (PS II) photochemical activity ($F_v/F_m$) decreased. The maximum photosynthetic rate ($A_{max}$) was higher under elevated $CO_2$ conditions than under ambient $CO_2$ conditions, whereas the maximum electron transport rate ($J_{max}$) was lower under elevated $CO_2$ conditions compared to ambient $CO_2$ conditions. The optimal temperature for photosynthesis shifted significantly by approximately $3^{\circ}C$ under the elevated $CO_2$ conditions. With the increase in temperature, the photosynthetic rate increased below the optimal temperature (approximately $30^{\circ}C$) and decreased above the optimal temperature, whereas the dark respiration rate ($R_d$) increased continuously regardless of the optimal temperature. The difference in photosynthetic rate between ambient and elevated $CO_2$ conditions was greatest near the optimal temperature. These results indicate that future increases in $CO_2$ will increase productivity by increasing the photosynthetic rate, although it may cause damage to the PS II reaction center as suggested by decreases in $F_v/F_m$, in soybean.

• 한국생물공학회:학술대회논문집
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• 2003.04a
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• pp.249-252
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• 2003

Maximal production of heteropolysaccharide-7(PS-7) with a batch culture for 48 hr was $10.0\;g/{\ell}$ and its conversion rate from 2% (w/v) glucose to PS-7 was 50%. After substitution of media, production of PS-7 continued and reached its maximal production. The highest productivity occurred when the fresh medium, which contained all ingredients, for the production of PS-7 was substituted. Higher production of PS-7 was maintained at a dilution rate of 0.0125, which was established as the optimal dilution rate for the production of PS-7 by B. indica HS-2001.

• Bulletin of the Korean Chemical Society
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• v.26 no.8
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• pp.1260-1264
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• 2005

Three new quaternary tantalum thiophosphates, $K_{0.18}TaPS_6,\;K_{0.28}TaPS_6,\;and\;Rb_{0.09}TaPS_6$ have been synthesized by using reactive alkali metal halide fluxes and structurally characterized by single crystal X-ray diffraction techniques. The crystal structures of $K_{0.18}TaPS_6,\;K_{0.28}TaPS_6,\;and\;Rb_{0.09}TaPS_6$ contain 3-dimensional open framework anions, $[TaPS_6]^{x-}$(x = 0.09, 0.18, 0.28) with the empty channel which disordered alkali metal cations, $K^+\;and\;Rb^+$ are located in. Crystal data: $K_{0.18}TaPS_6$, tetragonal, space group$I4_1$/acd (no. 142), a=15.874(3) $\AA$, c=13.146(4) $\AA$, V=3312.7(12) ${\AA}^3$, K, Z=16, R1=0.0545. Crystal data: $K_{0.28}TaPS_6$, tetragonal, space group $I4_1$/acd (no. 142), a=15.880(2) $\AA$, c=13.134(3) $\AA$, V=3312.1(10) ${\AA}^3$, Z=16, R1=0.0562. Crystal data: $Rb_{0.09}TaPS_6$, tetragonal, space group I41/acd (no. 142), a=15.893(3) $\AA$, c=13.163(4) $\AA$, V=3324.7(15) ${\AA}^3$, Z=16, R1=0.0432.

• Bulletin of the Korean Chemical Society
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• v.32 no.7
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• pp.2178-2182
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• 2011

Recently, the synthesis of ordered macroporous materials has received much attention due to its potential use as photonic band gap materials.$^1$ In this study, we have used the three-dimensional (3D) latex array template impregnated with benzenesulfonic acid (BSA), which is capable of catalyzing the reaction using tetraethyl orthosilicate (TEOS) as a precursor and distilled water. The polystyrene (PS) templates were reacted with TEOS in $scCO_2$ at 40 $^{\circ}C$ and at 80 bar. In the reactor, TEOS was filtrated into the PS particle lattice. After the reaction, porous silica materials were obtained by calcinations of the template. The stability test of the PS template in pure $CO_2$ was conducted before the main experiment. Scanning electron microscopy (SEM) images showed that the reaction in $scCO_2$ takes place only on the particle surface. This new method using $scCO_2$ has advantages over conventional sol-gel processes in its capability to control the fluid properties such as viscosity and interfacial tension. It has been found that the reaction in $scCO_2$ occurs only on the particle surface, making the proposed technique as more rapid and sustainable method of synthesizing inverse opal materials than conventional coating processes in the liquid phase and in the vapor phase.

• Journal of the Korean Society for Library and Information Science
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• v.52 no.1
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• pp.113-131
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• 2018

The study is to prove the necessity of librarian as the coordinator for the building and sustenance of "Community of Practice" in public libraries. Therefore, The study reviews literatures and conducts a survey how librarians think of their work from the perspective of CoP. The results of this study are as follows: "Community of Practice(CoP)" is the kind of community composed of "Domain", "Community" and "Practice" for knowledge circulation; The coordinator neither leader in CoP nor manager outside of CoP is necessary to sustain CoP by supporting management of CoP and promoting knowledge sharing; The programs and clubs designed by public librarians are potential CoPs; The potential CoPs turn into the sustainable CoPs when the participants of programs turn into the directors of programs; It means the coordinator of CoP is librarian in case of public libraries.

• Animal Bioscience
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• v.34 no.4
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• pp.734-742
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• 2021

Objective: The present study aimed to investigate the occurrence and species of coagulase-positive staphylococci (CoPS) and coagulase-negative staphylococci (CoNS) in retail pork meat samples collected during nationwide monitoring. The staphylococcal isolates were characterized for antimicrobial and zinc chloride resistance and enterotoxigenic potential. Methods: A total of 260 pre-packaged pork meat samples were collected from 35 retail markets in 8 provinces in Korea for isolation of staphylococci. Antimicrobial and zinc chloride resistance phenotypes, and genes associated with the resistance phenotypes were determined on the isolates. Furthermore, the presence and distribution of 19 staphylococcal enterotoxin (SE) genes and enterotoxin-like genes among the pork-associated staphylococci were determined by multiplex polymerase chain reaction-based assays using the specific primer sets. Results: A total of 29 staphylococcal strains (29/260, 11.1%) were isolated from samples of retail pork meat, 24 (83%) of which were CoNS. The four CoNS species identified were S. saprophyticus (n = 16, 55%), S. sciuri (n = 3, 10%), S. warneri (n = 3, 10%), and S. epidermidis (n = 2, 7%). Among the 29 isolates, four methicillin-resistant CoNS (MR-CoNS; three S. sciuri and one S. epidermidis) and one methicillin-resistant CoPS (MR-CoPS; one S. aureus) were identified. In addition, a relatively high level of tetracycline (TET) resistance (52%) was confirmed in CoNS, along with a predominant distribution of tet(K). The most prevalent SEs were sep (45%), and sen (28%), which were carried by 81% of S. saprophyticus. Conclusion: These findings suggest that CoNS, especially S. saprophyticus strains, in raw pork meat could be a potential risk factor for staphylococcal food poisoning (SFP), and therefore, requires further investigation to elucidate the role of SEls in SFP and virulence of the pathogen. Our results also suggest that CoNS from raw pork meat may act as a source for transmission of antimicrobial resistance genes such as staphylococcal cassette chromosome mec and tet(K).

• Korean journal of food and cookery science
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• v.12 no.4
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• pp.499-505
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• 1996

The facillities for Kimchi preservation were investigated in order to develop the taste, flavor and commercial quality of Kimchi during fermentation. Four kinds of facillities used for this experiment were PP(Polypropylene). PSC(Polypropylene+ceramic)and PPP was selected newly and laminated of three layers with PETG (Polyester G), PS (Polystyrene) and PETG. The change of total number of lactic acid Bacteria, pH, acidity, color, gas contents and free internal volume of package were measured for the Kimchi packaged by 4 facillities during 6 days fermentation at 15$^{\circ}C$. The total No. of lactic acid Bacteria within the Kimchi in the PPP facillity was more and remained longer time (120 hrs.) than other Kimchi in the PP, PS and PPC facillities. Also the pH of all Kimchi were decreased to pH 4 within 72 hrs. and the pH of Kimchi in the PPP facillity was kept as pH 4 for 120 hrs., so that was shown to be decreased more dully than others. In case of fimchi in the PPP facillity, the color was retained better, CO$_2$ contents was lower similar to PPC facillity, and swelling degree of free internal volume was higher than others. By the sensory evaluation, the Kimchi in the PPP facillity represented as better than others for color, flavor, texture and total preferences until 48 hrs. fermentation. And the PPP facillity is transparent, so these will be selected and confirmed more easily, also PPP facillity is so hard to endure the swelling pressure of internal gas. Therefore it is thought that the PPP facillity used as Kimchi package will be desirable for better taste, flavor, and commercial quality.

• Korean Chemical Engineering Research
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• v.57 no.4
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• pp.559-564
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• 2019

Hierarchical $ZnCo_2O_4$ hollow nanofibers were prepared by electrospinning and subsequent heat-treatment process. The spinning solution containing polystyrene (PS) nanobeads was electrospun to nanofibers. During heat-treatment process, PS nanobeads in the composite were decomposed and therefore generated numerous pores uniformly in the structure, which facilitated the heat transfer and gas penetration into the structure. The resulting hierarchical $ZnCo_2O_4$ hollow nanofibers were applied as an anode material for lithium-ion batteries. The discharge capacity of the nanofibers was $815mA\;h\;g^{-1}$ ($646mA\;h\;cm^{-3}$) after the 300th cycle at a high current density of $1.0A\;g^{-1}$. However, $ZnCo_2O_4$ nanopowders showed the discharge capacity of $487mA\;h\;g^{-1}$ ($450mA\;h\;cm^{-3}$) after 300th cycle. The excellent lithium ion storage property of the hierarchical $ZnCo_2O_4$ hollow nanofibers was attributed to the synergetic effects of the hollow nanofiber structure and the $ZnCo_2O_4$ nanocrystals composing the shell. The hierarchical hollow nanofiber structure introduced in this study can be extended to various metal oxides for various applications, including energy storage.

• Korean Journal of Environmental Agriculture
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• v.21 no.1
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• pp.17-23
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• 2002

In order to investigate effects if loess on the mycellial pellet formation a phosphate-solubilizing fungus. Aspergillus sp. PS-104 was cultured in potato dextrose broth containing loess. The strain formed an amorphous pellet or loose aggregates agitated at a low speed (50 rpm) while spherical and regular pellets at a high speed (150 rpm) The higher concentration of loess was added, the smaller size of a pellet was formed during the submerged culture of the strain. As shown in results, being cultured in the PDB medium supplemented with 1.0% loess the pellet size was maximally reduced to a fourth compared to the control. Evaluating the addition effect of several components of loess such as $SiO_2$, $Fe_2O_3$, $Al_2O_3$, $CaCO_3$, $CaSO_4$ and $MgCO_3$ on the reduction of mycellial pellet size the higher concentration was supplied, the smaller size of pellet was formed except $Al_2O_3$. And the smallest pellet size was recorded at the concentration of 1.0% (W/V) magnesium carbonate.