• Journal of Food Hygiene and Safety
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• v.14 no.1
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• pp.115-121
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• 1999

The effect of storage temperature and time on the contents of metal (Pb, Sn and Fe), vitamin C, color and pH was studied for canned pineapple juice (PJ) and pineapple slice (PS) which were stored for 120 hours at 5 and 2$0^{\circ}C$ and analyzed at 24 hours intervals. The results are as follows; 1. The metal contents of PJ and PS were in the rank of 24<48<72<96<120 hours by storage time at 5 and 2$0^{\circ}C$. These contents were increased to 44.1%/24 hrs of Ph, 18.0%/24 hrs of Sn, 34.6%/24 hrs of Fe but decreased to 6.0%/24 hrs of vitamin C in PJ and PS during 120 hrs. Storage times were correlation to contents of metal and pH but was not correlation to vitamin C contents. These were increased to 37.7%/24 hrs of Pb, 18.8%/24 hrs of Sn, 34.6%/24 hrs of Fe, but decreased to 6.0%/24 hrs of vitamin C. 2. These were increased to 10.6% of Pb, 3.7% of Sn, 11.3% of Fe in PJ and to 33.7% of Pb, 4.8% of Sn, 37.6% of Fe in PS at 2$0^{\circ}C$ than 5$^{\circ}C$ but vitamin C contents were decreased to 8.2% in PJ and 2.7% in PS at 2$0^{\circ}C$ than 5$^{\circ}C$. This fact suggests that more attention be paid in handling canned PJ and PS after opening in order to avoid the decreasing vitamin C and the hazard from Pb, Sn, Fe. 3. Changing factors in Pb, Sn, Fe and vatiamin C content were in the rank of storage temperature$0^{\circ}C$.

• Bulletin of the Korean Chemical Society
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• v.15 no.1
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• pp.37-45
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• 1994

$(NH_4)_{4.5}[H_{3.5}{\alpha}-PtMo_6O_{24}]{\cdot}1.5\;H_2O(A),\;(NH_4)_4[H_4{\beta}-PtMo_6O_{24}]{\cdot}1.5\;H_2O(B),\;and\;K_{3.5}[H_{4.5}{\alpha}-PtMo_6O_{24}]{\cdot}3\;H_2O(C)$ have been synthesized and their molecular structures have been also determined by single-crystal X-ray diffraction technique. The space groups, unit cell parameters, and R factors are as follows: Compound A, monoclinic, $A_{2/a}$, a= 19.074 (3), b=21.490 (3), c=15.183 (2) ${\AA};\;{\beta}$=109.67 (1) ${\AA}$; z=8; R=0.075($IF_0I>4{\sigma}(IF_0I);$ Compound B, triclinic, P$bar{1}$, a=10.776 (2), b=15.174 (4), c=10.697 (3) ${\AA};\;{\alpha}$ =126.29 (2), ${\beta}$=111.55 (2), ${\gamma}$=93.18 (2) ${\AA}$; Z=2; R=0.046($IF_0I>3{\sigma}(IF_0I);$): Compound C, triclinic, Pl, a=12.426 (2), b=13.884 (2), c=10.089 (1) ${\AA}$; ${\alpha}$=102.59 (2), ${\beta}$=110.73 (1), ${\gamma}$=53.93 (1) ${\AA}$; Z=2; R=0.074 ($IF_0I>3{\sigma}(IF_0I)$. Compounds A and C contain the well-known Anderson structure (planar structure) heteropoly oxometalate having approximate $bar{3}_m(D_{3d})$ symmetry, while compound B contains the bent structure heteropoly oxometalate having appproximate $2_{mm}(C2_v)$ symmetry. The bent structure and the planar one are geometrical isomers. These compounds are rot only novel heteroply molybdates containing platinate(IV) but also the first example of geometrical isomerism in the hexamolybdoheteropoly oxometalates. That isomerization surprisingly occurred because of the change of only 0.5 non-acidic hydrogen atom attached to the polyanion such as $[H_{3.5}{\alpha} -PtMo_6O_{24}]^{4.5-}{\to}[H_4{\beta}-PtMo_6O_{24}]^{4-}{\to}[H_{4.5}{\alpha} -PtMo_6O_{24}]^{3.5-}$. It seems that the gradual protonation of the polyanion plays an important role in that isomerism. These heteropolyanions form dimers by strong hydrogen bonds between two heteropolyanions in the respective crystal system.

• Journal of the Korean Chemical Society
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• v.43 no.2
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• pp.150-155
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• 1999

The ignition delay times behind reflected shock waves in $C_2H_6-O_2-Ar$ systems containing $CH_3Cl$ were measured for the range of temperatures between 1270 and 1544 K. The measurements indicated that $CH_3Cl$ inhibited the ignition of ethane ignition and the inhibition effects increased with increasing $CH_3Cl$ concentration. To clarify the inhibition effects of $CH_3Cl$ from the viewpoint of the reaction mechanism, computational analyses were performed in $C_2H_6-CH_3CI-O_2-Ar$ mixtures.

• Bulletin of the Korean Chemical Society
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• v.26 no.11
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• pp.1711-1716
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• 2005

Fragmentations and ion-molecule reactions of ionized cyclohexane propionic acid and cyclohexane butyric acid were studied using FTMS and theoretical calculations. The difference in bond dissociation depending on the aliphatic chain length was investigated and mechanisms for the possible rearrangements depending on the aliphatic carbon length were suggested. The most abundant fragment ion of the ionized cyclohexane propionic acid was c-$C_6H_{11}CH_2\;^+$ formed from the molecular ion by the direct C-C bond cleavage, while that of the ionized cyclohexane butyric acid was c-$C_6H_9C(OH)=OH^+$ formed by rearrangement of the molecular ion from the acid to diol form and loss of propyl radical. Stabilities of the radical and distonic ions of $C_nH_{2n}O^{+\bullet}$ formed from the molecular ion were compared. Protonated molecules were dissociated into smaller ions by losing one or two water molecules. The $[nM + H]^+$, $[nM + H - H_2O]^+$, and $[nM + H - 2H_2O]^+$ with n = 2 and 3 were generated by solvation with the neutral molecules in the ICR cell at long ion trapping time.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.7 no.2
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• pp.185-190
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• 1997

The 6H-SiC single crystals were grown using a self-designed crystal grower by the sublimation method. The grown crystals were typically 30 mm in diameter and 10 mm in length. Optimum growth conditions were established as follows : the temperature of the raw material was $2150~2250^{\circ}C$, the temperature of the substrate was $1950~2050^{\circ}C$, the temperature difference between the raw material and substrate was about $200^{\circ}C$, growth pressure was 50~200 torr and growth rate was 300~700 $\mu\textrm{m}$/hr. Optical microscopy was used for observing the surface of the 6H-SiC single crystal grown and the phenomenological approach was performed on the formation mechanism of the defects in the 6H-SiC crystal. Especially, the micropipes in the as-grown surface were examined to determine the formation mechanisms of the micropipes.

• Journal of Power System Engineering
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• v.17 no.4
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• pp.58-63
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• 2013

This paper presents the new cascade liquefaction cycles using $CO_2-C_2H_6-N_2$ and $CO_2-N_2O-N_2$. The performance of the cascade liquefaction cycles with respect to temperature differences in the LNG heat exchangers is analyzed using HYSYS software and then compared the performance of these cycles with phillips optimized cascade liquefaction cycle. The coefficient of performance of the new liquefaction cycles considered in this study decreases with the temperature differences in the LNG heat exchangers, but the compressor work, expander work and heat capacity in the LNG heat exchanger increases, respectively. From the comparison of performance of three cycles, the cascade liquefaction cycles using $CO_2-C_2H_6-N_2$ showed the highest COP. And the cycles using $CO_2-C_2H_6-N_2$ and $CO_2-N_2O-N_2$ presented the second and third highest COP, respectively. In the view of performance, the optimized cascade liquefaction cycle using $C_3H_8-C_2H_4-C_1H_4$ yields much better COP. But, in the environment view, it is found that the cascade liquefaction cycle using $CO_2-C_2H_6-N_2$ shows favorable characteristics.

• Journal of Korean Society of Environmental Engineers
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• v.28 no.1
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• pp.48-53
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• 2006

The purpose of this paper is to investigate the optimal condition of the SynGas production by reforming of propane using plasmatron. Plasma was generated by air and arc discharge. The effects of applied steam, $CO_2$ or Ni-catalyst on propane conversion, yield of hydrogen and $H_2/CO$ ratio as well as correlation of syngas were studied. When the variations of $O_2/C_3H_8$ flow ratio, $H_2O/C_3H_8$ flow ratio and $CO_2/C_3H_8$ flow ratio were $0.94{\sim}1.48,\;4.3{\sim}10\;and\;0.8{\sim}3.05$ respectively, Under the condition mentioned above, result of $H_2O/C_3H_8$ flow ratio was maximum $H_2$ concentration, or $28.2{\sim}31.6%$, and result of $H_2O/C_3H_8$ flow ratio with catalyst was minimum CO concentration or $6.6{\sim}7.1%$ and the ratio of hydrogen to carbon monoxide($H_2/CO$) were $3.89{\sim}4.86$.

• YAKHAK HOEJI
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• v.31 no.4
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• pp.219-223
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• 1987

2-Cyclohexylimino-3-cyclohexyl-5-methyl-4-oxo-2H, 5H-1, 3-oxazino [5,6-C]-1, 2-benzothiazine-6,6-dioxide 2 was hydrolized in d-HCl/$CH_3$CN to give 5-methyl-3-cyclohexyl-2H, 5H-1, 3-oxazino [5, 6-C]-1, 2-benzothiazine-2, 4(3H)-dione 6, 6-dioxide 3 in 82% yield. The alkaline hydrolysis of 3 afforded to 4-hydroxy-2-methyl-N-(cyclohexyl)-2H-1, 2-benzothiazine-3-carboxamide-1, 1-dioxide 4 in 88% yield. On the other hand 3 was synthesized from 4 and ethylchloroformate on the reversed procedure.

• Korean Journal of Ichthyology
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• v.17 no.2
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• pp.131-141
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• 2005

The ichthyofauna and structure of the fish community of Hapcheon Lake on the Hwang River were surveyed at six localities from May 2004 to Feb. 2005. There were 36 species belonging to 31 genera and 12 families in the Hapcheon Lake system. Of these, 24 species (66.7%) were cyprinids; cobitids and centropomids were next with 2 species (5.6%) each. The dominant species in the Hapcheon Lake system was Hemiculter eigenmanni (relative abundance 28.4%), the subdominant species Hemibarbus labeo (24.1%). Ten species (28.3%) of the 36 were Korean endemic species. Among the endemic species, H. eigenmanni and Squalidus chankaensis tsuchigae were abundant at each locality except site 6, but the eight other species were rare. In biomass, H. labeo comprised about 36.5% of the total weight, H. eigenmanni 22.3%, Cyprinus carpio 7.5%, Hypomesus nipponensis 6.9%, Culter brevicauda 3.7% and Lepomis macrochirus 3.6%. Average dominance, diversity, and evenness index of the fish community collected from six localities in the Hapcheon Lake system were 0.21, 0.85, and 0.67, respectively.

• Microbiology and Biotechnology Letters
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• v.20 no.2
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• pp.164-168
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• 1992

Enzymatic properties of avicelase, carboxymethyl cellulase (CMCase) and P-glucosidase produced by Cellulomonas sp. YE-5 were studied. Optimal temperature and pH of avicelase were 40t and 6.0, and those of CMCase and P-glucosidase were $45^{\circ}C$ and 6.5. Avicelase and CMCase were stable between pH 5.0 and 9.5, and &glucosidase was stable between pH 5.5 and 8.0. Avicelase and P-glucosidase were inactivated when incubated at $35^{\circ}C$ for 6 hrs, and CMCase was at $40^{\circ}C$ for 6 hrs. All cellulases were strongly inhibited by $Cu^{2+} \; and \; Zn^{2+}. K_m$ values of avicelase for avicel, CMCase I and CMCase II for CM-cellulose, and ($\beta$-glucosidase for p-nitrophenyl-$\beta$-D-glucoside (PNPG) were 4.76, 16.4, 16.4 $\mu g$/ml and 3.51 mM, respectively.