• Journal of Powder Materials
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• v.11 no.4
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• pp.322-327
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• 2004

Ultrafine titanium carbide particles were synthesized by the reaction of liquid-magnesium and vaporized TiCl$_{4}$+C$_{x}$Cl$_{4}$(x = 1 and 2) solution. Fine titanium carbide particles with about 50 nm were successfully produced by combining Ti and C atoms released by chloride reduction of magnesium, and vacuum was then used to remove the residual phases of MgCl$_{2}$ and excess Mg. Small amounts of impurities such as O, Fe, Mg and Cl were detected in the product, but such problem can be solved by more precise process control. The lattice parameter of the product was 0.43267 nm, near the standard value. With respect to the reaction kinetics, the activation energy for the reactions of TiCl$_{4}$+C$_{2}$Cl$_{4}$and Mg was found to 69 kJ/mole, which was about half value against the use of TiCl$_{4}$+CCl$_{4}$, and such higher reactivity of the former contributed to increase the stoichiometry until the level of TiC$_{0.96}$ and decrease the free carbon content below 0.3 wt.%.

• Journal of the Korean Society of Combustion
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• v.5 no.1
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• pp.7-18
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• 2000

Numerical simulations of counterflow non-premixed $CH_4/C_2HCl_3/Air$ flames added 8%(by volume) C2HCl3 on the fuel side are conducted at atmospheric pressure using a detailed chemical reaction mechanism in order to understand the effect of strain rates. A detailed sensitivity analysis is also performed in order to assess the relative influence of each reaction on the flame established at a strain rate of 200s-1. The structure of flames (i.e., temperature, velocity, and concentration of species) established at both a strain rate of 150s-1 and 300s-1 are investigated. As the strain rate increases, the "flame zone" is restricted to a narrower range and the position of maximum temperature is shifted to the fuel side. The concentrations of major species, H2O, CO, H2, HCl, Cl2, and Cl are decreased with increased strain rate. The reaction involving chlorine, CH4 + Cl $\rightarrow$ CH3 + HCl, instead of the reaction, CH4 + H $\rightarrow$ CH3 + H2 influences the consumption of methane. C2HCl3 + OH $\rightarrow$ CHCl2 + CHOCl and HCl + OH $\rightarrow$ H2O + Cl, are major reactions, through which OH radicals are consumed.

• Journal of Microbiology and Biotechnology
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• v.27 no.2
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• pp.219-225
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• 2017

An aqueous chlorine dioxide ($ClO_2$) treatment combined with highly activated calcium oxide (CaO) and mild heat was tested for inactivating naturally existing bacteria and Escherichia coli O157:H7 inoculated on fresh-cut kale. Kale samples were treated with different concentrations of $ClO_2$ (10, 30, and 50 ppm), CaO (0.01%, 0.05%, 0.1%, and 0.2%), and mild heat ($25^{\circ}C$, $45^{\circ}C$, $55^{\circ}C$, and $65^{\circ}C$) as well with combinations of 30 or 50 ppm $ClO_2$ and 0.2% CaO at $55^{\circ}C$ for 3 min. An increasing concentration of $ClO_2$ and CaO significantly reduced the microbial population compared with the control. In addition, mild heating at $55^{\circ}C$ elicited greater microbial reduction than the other temperatures. A combined treatment of 50 ppm $ClO_2$ and 0.2% CaO at $55^{\circ}C$ reduced the population of naturally existing bacteria on kale by 3.10 log colony forming units (CFU)/g, and the counts of E. coli O157:H7 were below the detection limit (1 log CFU/g). In addition, no significant differences in the Hunter color values were evident in any treatment during storage. Therefore, a combined treatment of $ClO_2$ and active CaO at $55^{\circ}C$ can be an effective sanitizing method to improve the microbiological safety of fresh-cut kale without affecting its quality.

• Journal of People, Plants, and Environment
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• v.23 no.4
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• pp.445-453
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• 2020

Background and objective: Calcium chloride (CaCl₂) and sodium chloride (NaCl) are commonly used as a deicing agent in South Korea and penetrate the soil on the roadside, causing damage to plants. This study was conducted to investigate the salinity reduction effect of Pennisetum alopecuroides and the chemical characteristics of soil leachate. Methods: The plants were treated with five different concentrations of CaCl₂ (0, 1, 2, 5, and 10g·L^-1) and were grouped into the Cont., C1, C2, C5, and C10 groups. CaCl₂ of 200 m·L^-1 was sprayed to each plant once every two weeks. The growth of P. alopecuroides (plant height, leaf length, leaf width and the number of leaves) was measured. The level of EC and pH, and exchangeable cations (K⁺, Ca²⁺, Na⁺, and Mg²⁺) in the leachate of soil was monitored. Results: The pH of soil leachate decreased as the CaCl₂ concentration increased, and the EC increased significantly. The content of K⁺ did not change significantly until the concentration of CaCl₂ reached 5 g·L^-1, but the content of Ca²⁺, Na⁺, and Mg²⁺ significantly increased. The plant height, leaf length, and leaf width of P. alopecuroides showed the highest value in CaCl₂ 1 g·L^-1 followed by CaCl₂ 2 g·L^-1 and the control group. Root fresh weight was the highest in CaCl₂ 2 g·L^-1. On the other hand, there was no change in the shoot fresh weight, dry weight and root dry weight, and P. alopecuroides growth inhibition at the concentration of 5 g·L^-1 or higher in the plant height and leaf length. Conclusion: P. alopecuroides is relatively highly salt-tolerant and can improve the salt damaged soil by lowering the content of the salt-based exchangeable K⁺ ions.

• Bulletin of the Korean Chemical Society
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• v.18 no.3
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• pp.305-310
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• 1997

The synthesis and characterization of the platinum heterocyclic carboxaldehyde thiosemicarbazone complexes [NC5H4CRNNC(S)NHR'PtCl] (R=H, R'=CH3(1); R=CH3, R'=CH3(2); R=CH3, R=H(3)) and diphenylphosphinophenyl carboxaldehyde thiosemicarbazone complexes [Ph2PC6H4CHNNC(S)NHRPtCl] (R=CH3(5); R=iC3H7(6); R=Ph(7)) are described. Compounds 1-3 were prepared by reaction of Pt(SEt2)2Cl2 with 2-acetylpyridine-4-alkylthiosemicarbazone in the presence of NEt3. Compounds 5-7 were prepared using Pt(SEt2)2Cl2 in toluene with diphenylphosphinophenyl carboxaldehyde alkylthiosemicarbazone. The compounds have been characterized by microanalysis, NMR (1H, 13C, 31P) spectroscopy, and single-crystal X-ray diffraction. X-ray single crystal diffraction analysis reveals that compound 5 is a mononuclear platinum compound with P,N,S-coordination mode.

• Journal of the Korean Magnetic Resonance Society
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• v.15 no.2
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• pp.146-156
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• 2011

The line widths and spin-lattice relaxation times of protons in $[N(C_2H_5)_4]_2CoCl_4$ and $[N(CH_3)_4]_2CoCl_4$ single crystals were investigated in the temperature range 160-400 K. The temperature dependences of the spin-lattice relaxation times are attributed to the molecular motions of the ethyl and methyl groups in the $[N(C_2H_5)_4]^+$ and $[N(CH_3)_4]^+$ ions respectively. The NMR line widths indicate that the ethyl groups in $[N(C_2H_5)_4]_2CoCl_4$ have one more degree of freedom than the methyl groups in $[N(CH_3)_4]_2CoCl_4$. The experimental results are interpreted in terms of the reorientations of the methyl and ethyl groups.

• Journal of Applied Biological Chemistry
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• v.54 no.3
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• pp.153-158
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• 2011

Optimal culture conditions were characterized for production of crude biosurfactant of Bacillus subtilis JK-1. During incubation of B. subtilis JK-1, the bacterial growth pattern, changes of the surface tension at variable temperatures, pH and NaCl concentrations in bacterial culture medium were studied. The strain was able to grow and produce biosurfactant at $15-45^{\circ}C$, in the pH range of 6-10, and at 0-10% (w/v) NaCl. In case, culture broth pH was gradually changed to neutral or weak alkaline. Optimal culture conditions for crude biosurfactant production were at $35^{\circ}C$ and pH 7.0 after 48 h incubation and the surface tension of biosurfactant was 24.0 mN/m. Besides, as the concentration of NaCl was increased from 0 to 10% (w/v), the growth was decreased, pH of the culture broth was converted from weak alkaline to acidic, and the surface tension rised.

• Proceedings of the Korean Society of Postharvest Science and Technology of Agricultural Products Conference
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• 2003.04a
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• pp.122-122
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• 2003

다슬기의 분말(PSB)과 그 회화분(ASB)으로부터 체내 흡수력이 높은 젖산칼슘의 제조조건과 색상, 용해도 및 관능적 품질을 조사하였다. PSB로부터 제조한 젖산칼슘(PSB-CL)의 PSB 및 젖산 100 mL에 대한 수율은 젖산농도가 10%일 때는 300% 및 15 g, 20%일 때는 260% 및 20 g이었으며, ASB로 제조한 젖산칼슘(ASB-CL)의 ASB 및 젖산 100 mL에 대한 수율은 10% 젖산에서는 400% 및 60 g, 20% 젖산에서는 329% 및 66 g으로 원료량을 기준으로 하였을 때는 다같이 젖산농도의 증가에 따라 감소하였으나 젖산의 부피를 기준으로 하였을 때는 젖산농도의 증가에 따라 증가하였다. Dehydated PSB-CL 및 ASB-CL 제조의 적정온도와 시간은 10$0^{\circ}C$에서는 각각 4 및 5시간, 12$0^{\circ}C$에서는 3 및 4시간, 15$0^{\circ}C$에서는 1 및 2시간으로 ASB-LA의 경우가 짧았다. IR 및 H-NMR spectrum의 분석결과 PBS-LA와 ASB-LA의 구조는 Ca($CH_3$CHOH$CO_2$)$_2$임이 확인되었다. 무수 PSB-CL 및 ASB-CL의 칼슘함량은 각각 15.4%(w/w)와 17.3%(w/w)로 이론 값의 각각 84.2%와 94.5%를 나타내었으며, 미량의 Fe, Na, Mn Zn을 함유하였다. PBS-CL와 ASB-CL의 색상은 각각 연한 황색과 연녹색을 지닌 백색을 띠었다. pH 3~8로 조정한 증류수에서 PSB-CL과 ASB-CL의 평균 용해도는 각각 5.43 g/100 mL 및 6.11 g/100 mL로 standard CL의 4.74 g/mL에 비하여 높았다. 국간장을 제외한 대부분의 액체식품(3% 소금물, 소주, 진간장, 국간장, 포도주스 및 오렌지주스)에서의 용해도는 PSB-CL(3.14~5.03 g/100 mL)과 ASB-CL(4.69~6.05 g/100 mL)이 standard CL(2.94~5.84 g/100 mL)에 비하여 높았다. 관능검사 결과, ASB-CL은 신맛이 낮아 사용범위가 높은 것으로 평가되었으며 PSB-CL는 쓴맛은 높으나 떫은맛이 낮고 구수한 맛이 강하여 식품에의 응용이 기대된다.

• Journal of the Korean Institute of Gas
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• v.2 no.2
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• pp.40-47
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• 1998

This study describes a synthesis of spinel-type $Fe_3O_4$ for decomposition of carbon dioxide, using $Fe_3O_4$ $7H_2O$ and NaOH, at $40^{\circ}C$ for 20 h. with change of their chemical equivalent ratio from 0.50 to 0.75, 1.00, 1.25 and 1.50, respectively. Addition of 0.1-1.00 mole percentage $NiCl_2,\;RhCl_3$ to the particles of $Fe_3O_4$, Prepared by reacting chemical equivalent ratio 1.00, afforced spinel $Fe_3O_4$. The structure of $Fe_3O_4$ and $NiCl_2,\;RhCl_3$-added $Fe_3O_4$ was investigated with XRD and SEM, respectively.

• Transactions on Electrical and Electronic Materials
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• v.4 no.2
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• pp.29-34
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• 2003

Ferroelectric YMnO$_3$ thin films were etched with Ar/C1$_2$ and CF$_4$/C1$_2$ Plasma. The maximum etch rate of YMnO$_3$ thin film was 300 $\AA$/min at a Cl$_2$/Ar gas mixing ratio of 8/2, an RF power of 800 W, a do bias of-200 V, a chamber pressure of 15 mTorr, and a substrate temperature of 3$0^{\circ}C$. From the X-ray photoelectron spectroscopy (XPS) analysis, yttrium was not only etched by chemical reactions with Cl atoms, but also assisted by Ar ion bombardments in Ar/C1$_2$ plasma. In CF$_4$/C1$_2$ plasma, yttrium formed nonvolatile YF$_{x}$ compounds and remained on and the etched surface of YMnO$_3$. Manganese etched effectively by forming volatile MnCl$_{x}$ and MnF$_{y}$. From the X-ray diffraction (XRD) analysis, the (0004) diffraction peak intensity of the YMnO$_3$ thin film etched in Ar/Cl$_2$ plasma shows lower than that in CF$_4$/Cl$_2$ plasma. It indicates that the crystallinty of the YMnO$_3$ thin film is more easily damaged by the Af ion bombardment than the changes of stoichiometry due to nonvolatile etch by-products.cts.s.