• Journal of Integrative Natural Science
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• v.8 no.4
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• pp.250-257
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• 2015

The crystal structure of the potential active 3-(4-ethylphenyl)-3H-chromeno[4,3-c]isoxazole-3a(4H)-carbonitrile ($C_{19}H_{16}N_2O_2$) has been determined from single crystal X-ray diffraction data. In the title compound crystallizes in the monoclinic space group $P2_1/c$ with unit cell dimension a=6.6869 (8) ${\AA}$, b=15.8326 (19) ${\AA}$ and c= 15.237 (2) ${\AA}$ [${\alpha}=90^{\circ}$, ${\beta}=100.663^{\circ}$ and ${\gamma}=90^{\circ}$]. In the structure chromene, isoxazole and carboxylate are almost coplanar each other. All geometrical parameters revelled that chromene ring of pyran ring adopt sofa conformation. The crystal packing is stabilized by intermolecular C-H...N and C-H...O hydrogen bond interaction.

• Bulletin of the Korean Chemical Society
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• v.20 no.1
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• pp.65-68
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• 1999

Novel mononuclear group 13 metal complexes with the formula (R2M){NC5H4C(CH3)NNC(S)NH(C6H5)} (M=Al, R=iC4H9 (1); M=Ga, R=iC4H9 (2); M=Al, R=CH2SiMe3 (3); M=Ga, R=CH2SiMe3 (4)) result when 2-acetyl pyridine 4-phenyl-thiosemicarbazone ligand is mixed with trialkyl aluminum or trialkylgallium. These compounds 1-4 are characterized by microanalysis, NMR (1H, 13C) spectroscopy, mass spectra, and singlecrystal X-ray diffraction. X-ray single-crystal diffraction analysis reveals that 1 is mononuclear metal compound with coordination number of 5 and N, N, S-coordination mode.

• Journal of the Korean Ceramic Society
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• v.28 no.2
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• pp.130-140
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• 1991

The powders of the system Si3N4-Y2O3-AlN were prepared using Si(OC2H5)4 and YCl3.6H2O together with commercial AlN powder. $\alpha$-Si3N4 was prepared by the carbothermal reduction and nitridation of the hydrolyzed gel at 135$0^{\circ}C$ for 10h in N2 atmosphere. YCl3.6H2O was observed to be changed to Y2O3 during the reaction. $\alpha$-Sialon(X=0.2, 0.4, 0.6) ceramics were obtained by hot-pressing the Si3N4-Y2O3-AlN mixture at 178$0^{\circ}C$ for 1h under 30 MPa. The content of $\alpha$-Sialon increased with increasing metal solubility(x value) and $\alpha$-Sialon single phase was obtained at the metal solubility of 0.6. With increasing metal solubility, flexural strength, fracture toughness and thermal shock resistence were decreased, while the microhardness was increased. Large elongated $\beta$-Si3N4 grains were mainly observed at lower metal solubility. Mechanical prorerties of the sintered ceramics with X=0.2 were measured as follows : flexural strength ; 650 MPa, fracture toughness ; 3.63 MN/m3/2, hardness ; 14.7 GPa, thermal shock resistence temperature ; 58$0^{\circ}C$.

• Analytical Science and Technology
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• v.20 no.4
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• pp.355-360
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• 2007

The title complex, $(C_3H_{12}N_2)[\{Cd(H_2O)(C_6H_5O_7)\}_2]{\cdot}6H_2O$, I, has been prepared and its structure characterized by FT-IR, EDS, elemental analysis, ICP-AES, and X-ray single crystallography. It is triclinic system, $P{\bar{1}}$ space group with a = 10.236(2), b = 11.318(2), c = $13.198(2){\AA}$, ${\alpha}=77.95(1)^{\circ}$, ${\beta}=68.10(1)^{\circ}$, ${\gamma}=78.12(1)^{\circ}$, V = $1373.5(3){\AA}^3$, Z = 2. Complex I has constituted by protonated 1,3-diaminopropane cations, citrate coordinated cadmium(II) anions, and free water molecules. The central cadmium atoms have a capped trigonal prism geometry by seven coordination with six oxygen atoms of three different citrate ligands and one water molecule. Citrate ligands are bridged to three different cadmium atoms. Each cadmium atom is linked by carboxylate and hydroxyl groups of citrate ligand to construct an one-dimensional ladder-type assembly structure. The polymeric crystal structure is stabilized by three-dimensional networks of the intermolecular O-H${\cdots}$O and N-H${\cdots}$O hydrogen-bonding interaction.

• Journal of Environmental Health Sciences
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• v.27 no.1
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• pp.27-35
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• 2001

This aim of the work presented in this paper is to investigate the factors that affcet chlorine decay and to develop functional relationships that can be used to enhance the durability of network models. predictive relationships were established that correlated the rate of chlorine decay to the various water conditions such as DOC, N $H_3$-N, initial chlorine, contact time, temperature and pH values. Free chlorine residual decreased with increasing temperature, DOC, N $H_3$-N, reaction time and chlorine dose. At 2$0^{\circ}C$, pH 7, The initial chlorine demand per mg as DOC/L and mg as N $H_3$-N/L was about 0.43, 2.69 mg/$\ell$ respectively at 180 minutes contact time. The Reaction between chlorine and humic acids was lasted intil 48hr, but the reaction between chlorine and N $H_3$-N was almost completed in 180 min. When the temperature is raised by 1$0^{\circ}C$, chlorine is more consumed about 0.25 mg/$\ell$ in the absence of organic substances and it is more consumed about 3.4 mg/$\ell$ in the presence of humic acid (5 mg/$\ell$) in water at pH 7 for 180 min. Regression Analysis created the resulting prediction equation for the chlorine decay in a SPSS package of the computer system. The model is as follows; $C_{t}$=1.239+0.707(Co)-0.000529(Time)-0.0112(Temp)+0.02227(pH)-0.42(DOC)-2.132(N $H_3$-N).).

• Journal of Korean Society of Environmental Engineers
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• v.28 no.3
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• pp.286-291
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• 2006

We studied possibility of mixing treatment of livestock wastewater and sewage using Phanerochaete chrysosporium PSBL-1. Our study showed that 97.6% of SS and 95% of T-P removal efficiency was achieved when 2 mL BF02(a coagulant) and 100 mL C-210EL(a cationic polymer) were added to the mixture(2:1, v/v) of livestock wastewater and sewage. We studied treatment characteristic of Phanerochaete chrysosporium PSBL-1, after were mixed pretreated wastewater and sewage by dillution ten times about livestock wastewater. The removal efficiency of NBDCOD(non-biodegradable COD), $NH_3-N$ and T-N was increased according to increase of pH. That is, T-N concentration of effluent was satisfied 60 mg/L by drain water waterqulity standard of livestock wastewater public treatment facilities with 35 mg/L from a lapse of five days at pH 6.7, 51 mg/L from a lapse of three days at pH 8 and 33 mg/L from a lapse of one day at pH 10. Moreover $COD_{Mn}$ concentration of effluent was satisfied 40 mg/L by drain water waterqulity standard of livestock wastewater public treatment facilities after a laps of one day at all pH. Organics and nitrogen concentrations of effluent were higher case with addition of V.A.(veratryl alcohol) than case without addition of V.A.(veratryl alcohol). $COD_{Mn}$ concentration of effluent satisfied drain water qulity standard of livestock wastewater public treatment facilities from a lapse of one day, when C/N rate(3:1) of influent was not controled. T-N satisfied that from a lapse of two days, when C/N rate was controled with $4{\sim}6$.

• Analytical Science and Technology
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• v.19 no.4
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• pp.309-315
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• 2006

Two piperazine-templated metal sulfate complexes, $(C_4N_2H_{12})[Ni(H_2O)_6](SO_4)_2$, I and ($C_4N_2H_{12}$) $[Co(H_2O)_6](SO_4)_2$, II, have been synthesized by hydro/solvothermal reactions and their crystal structures analyzed by single crystal X-ray diffraction methods. Complex I crystallizes in the monoclinic system, $P2_1/n$ space group, a=12.920(3), b=10.616(2), $c=13.303(2){\AA}$, ${\beta}=114.09(1)^{\circ}$, Z=4, $R_1=0.030$ for 3683 reflections; II: monoclinic $P2_1/n$, a=12.906(3), b=10.711(2), $c=13.303(2){\AA}$, ${\beta}=114.10(2)^{\circ}$, Z=4, $R_1=0.032$ for 4010 reflections. The crystal structures of the piperazine-templated metal(II) sulfates demonstrate zero-dimensional compound constituted by diprotonated piperazine cations, metal(II) cations and sulfate anions. The structures of complex I and II are substantially isostructural to that of the previously reported our piperazine-templated copper(II) sulfate complex $(C_4N_2H_{12})[Cu(H_2O)_6](SO_4)_2$. The central metal(II) atoms are coordinated by six water molecules in the octahedral geometry. The crystal structures are stabilized by three-dimensional networks of the $O_{water}-H{\cdots}O_{sulfate}$ and $N_{pip}-H{\cdots}O_{sulfate}$ hydrogen bonds between the water molecules and sulfate anions and protonated piperazine cations. Based on the results of thermal analysis, the thermal decomposition reactions of the complex I was analyzed to have three distinctive stages whereas the complex II proceed through several stages.

• Bulletin of the Korean Chemical Society
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• v.33 no.10
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• pp.3177-3183
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• 2012

The carbon nanofibers (CNFs) used in this study were synthesized with an iron catalyst and ethylene as a carbon source. A concentration of 30 wt % iron(III) acetylacetonate was dissolved in resol type phenol resin and polyurethane foam was put into the solution. The sample was calendered after being cured at $80^{\circ}C$ in air for 24 h. Stabilization and carbonization of the resol type phenol resin and reduction of the $Fe^{3+}$ were completed in a high-temperature furnace by the following steps: 1) heating to $600^{\circ}C$ at a rate of $10^{\circ}C/min$ with a mixture of $H_2/N_2$ for 4 h to reduce the $Fe^{3+}$ to Fe; 2) heating to $1000^{\circ}C$ in $N_2$ at a rate $10^{\circ}C/min$ for 30 minutes for pyrolysis; 3) synthesizing CNFs in a mixture of 20.1% ethylene and $H_2/N_2$ at $700^{\circ}C$ for 2 h using a CVD process. Finally, the structural characterization of the CNFs was performed by scanning electron microscopy and a synthesis analysis was carried out using energy dispersive spectroscopy and X-ray photoelectron spectroscopy. Specific surface area analysis of the CNFs was also performed by $N_2$-sorption.

• Journal of the Korean Mathematical Society
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• v.32 no.3
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• pp.471-482
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• 1995

A complex n-dimensional Kaehlerian manifold of constant holomorphic sectional curvature c is called a comples space form, which is denoted by $M_n(c)$. A complete and simply connected complex space form consists of a complex projective space $P_nC$, a complex Euclidean space $C^n$ or a complex hyperbolic space $H_nC$, according as c > 0, c = 0 or c < 0. The induced almost contact metric structure of a real hypersurface M of $M_n(c)$ is denoted by $(\phi, \zeta, \eta, g)$.

• Journal of the Korean Ceramic Society
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• v.28 no.3
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• pp.189-196
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• 1991

Si(OC2H5)4, commercial AlN and Y2O3 powder were used as the precusor of Si3N4, AlN, Y2O3, respectively. After Si3N4 powder was synthesized by carbothermal reduction and nitridation at 135$0^{\circ}C$ for 13h in N2 atmosphere, characteristics of synthesized powder and the ceramics sintered at 178$0^{\circ}C$ for 1h under 30MPa were investigated. In order to evaluate the reliability of sintered body, Weibull modulus was investigated. Premixing of carbon black as a reduction agent had no effect on Si(OH)4 formation, and Si3N4 powder synthesized from Si(OC2H5)4 was $\alpha$-Si3N4 single phase. Mechanical properties of sintered body were measured as follows : flexural strength ; 750MPa, fracture toughness ; 3.71Mn/3/2, hardness : 17.4GPa, thermal shock resistence temperature ; $600^{\circ}C$. Flexural strength at room temperature was 750MPa and was retained up to 110$0^{\circ}C$. The Weibull modulus of sintered body was 10.7.