• Journal of Magnetics
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• v.8 no.4
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• pp.138-141
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• 2003

$Ni_{0.65}Zn_{0.35}Fe_2O_4$thin films were prepared by using a sol-gel method. Their crystallographic, dielectric and magnetic properties were investigated as a function of Cu contents by means of an X-ray diffractometer (XRD), X-ray reflectivity, LCZ meter (NF2232), a vibrating sample magnetometer (VSM), and an atomic force microscope (AFM). From typical C-V measurements for $Ni_{0.65}Zn_{0.35}Fe_2O_4$ thin films on p-type silicon substrate, the surface charge density was calculated as 1.4 ${\mu}$C/$m^2$. The dielectric constant evaluated from the capacitance at the accumulation state was 28. The high $H_{c}$ and low $M_{sat}$ at x=0.0 and 0.1 were due to the growth of the ${\alpha}$-$Fe_2O_3$ phase having antiferromagnetic properties. The rapidly decreased $H_{c}$ and increased $M_{sat}$ at x=0.2 and 0.3 can be explained that the ${\alpha}$-$Fe_2O_3$ phases have completely disappeared at x=0.3 and so, non-magnetic defects are minimized. The $M_{sat}$ was slightly decreased and the $H_{c}$ was increased above at x=0.3 because the increase of grain boundary due to smaller grain size acts as defects during magnetization process.

• Proceedings of the Korean Magnestics Society Conference
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• 2002.04a
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• pp.82-83
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• 2002

• Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
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• 2003.02a
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• pp.129-132
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• 2003

Yttria stabilized zirconia (YSZ) buffer layers were deposited by a metal organic chemical vapor deposition (MOCVD) technique using single liquid source for the application of YBa$_2$Cu$_3$$O_{7-x}$ (YBCO) coated conductor. Y:Zr mole ratio was 0.2:0.8, and tetrahydrofuran (THF) was used as a solvent. The (100) single crystal MgO substrate was used for searching deposition condition. Bi-axially oriented CeO$_2$ and NiO films were fabricated on {100}〈001〉 Ni substrate by the same method and used as templates. At a constant working pressure of 10 Torr, the deposition temperatures (660~80$0^{\circ}C$) and oxygen flow rates (100~500 sccm) were changed to find the optimum deposition condition. The best (100) oriented YSZ film on MgO was obtained at 74$0^{\circ}C$ and $O_2$ flow rate of 300 sccm. For YSZ buffer layer with this deposition condition on CeO$_2$/Ni template, full width half maximum (FWHM) values of the in-plane and out-of-plane alignments were 10.6$^{\circ}$ and 9.8$^{\circ}$, respectively. The SEM image of YSZ film on CeO$_2$/Ni showed surface morphologies without microcrack.k.

• Journal of the Korean Magnetics Society
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• v.11 no.1
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• pp.14-20
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• 2001

The structure, shape, size, and magnetic properties of Ni$_{0.5}$Cu$_{0.1}$Zn$_{0.4}$Fe$_2$O$_4$ have been investigated as a function of annealing temperatures. In order to control the microwave absorbing properties of ferrite-rubber composite and the complex losses (magnetic loss and conduction loss), the effect of carbon addition was also studied. It was found that the coercive force decreased with increasing heat-treatment temperatures. Relative complex permeability and reflection loss were measured by the network analyzer. As a result, the natural resonance occurred in the low frequency tinge, and the matching frequency of the ferrite-rubber composite prepared at 130$0^{\circ}C$ was found to be lower. As heat-treatment temperatures were increased, the magnetic loss ($\mu$$_{r}$", $\mu$$_{r}$′) and the dielectric loss ($\varepsilon$$_{r}$"/$\varepsilon$$_{r}$′) were increased. It was caused that the absorption characteristics of the absorber were improved. The conduction loss and magnetic loss were expected to be occurred together because two matching frequencies were shown with carbon addition. It was confirmed that the matching frequency of the microwave absorber could be controlled by controlling heat-treatment temperatures and carbon additions.ons.tions.

• Environmental Engineering Research
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• v.19 no.3
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• pp.205-214
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• 2014

Petroleum a vital commodity affecting every aspect of 21st century. Toxicity and adverse effects of sulphur as catalyst in petroleum products is of great concern required development of techniques for desulphurization in compliance with the International standards. Installation of desulphurizing units costs over $200 million per unit placing economic burden on developing countries like Pakistan. Present study analysis of commercial fuels (station petrol and jet fuel JP8) on gas chromatography-mass spectrometry (GC-MS) identified sulphur concentration of 19.94 mg/L and 21.75 mg/L, respectively. This scenario urged the researcher to attempt synthesis of material that is likely to offer good adsorption capacity for sulphur. Following protocol of sol-gel method, transition metals (Ni, Cu, Zn) solution is gelated with tetraethoxysilane (TEOS; silica precursor) using glycerol. Fourier transform infrared spectroscopy (FTIR) spectra revealed bonding of Zn-O, Cu-O, and Ni-O by stretching vibrations at $468cm^{-1}$, $617cm^{-1}$, and $468cm^{-1}$, respectively. Thiophene and Benzothiophene mixed in n-heptane and benzene (4:1) for preparation of Model Fuels I and II, respectively. Each of silica based metal was applied as adsorbent in batch mode to assess the removal efficiency. Results demonstrated optimal desulphurization of more than 90% following efficacy order as Si-Ni > Si-Zn > Si-Cu based adsorbents. Proposed multilayered (Freundlich) adsorption mechanism follows ${\pi}$-complexation with pseudo secnd order kinetics.

• 한국초전도학회:학술대회논문집
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• v.13
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• pp.32-32
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• 2003

• Bulletin of the Korean Chemical Society
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• v.17 no.9
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• pp.790-793
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• 1996

The azacrown compound, 1,7-dioxa-4,10,13-triazacyclopentadecane-N,N',N"-tri(methyl-acetic acid)(N3O2-tri(methylacetic acid)) was synthesized by modified procedure of Krespan. Potentiometric method has been used to determine the protonation constants of N3O2-tri(methylacetic acid) and stability constants of complexes on the divalent transition metal ions (Co2+, Ni2+, Cu2+, and Zn2+) and trivalent metal ions (Ce3+, Eu3+, Gd3+, and Yb3+) with N3O2-tri(methylacetic acid). The stability constants for the complexes of the divalent transition metal ions studied in the present work with N3O2-tri(methylacetic acid) were 11.4 for Co2+, 11.63 for Ni2+, 13.51 for Cu2+, and 11.65 for Zn2+, respectively. Thus, the order of the stability constants for complexes on the transition metal ions with N3O2-tri(methylacetic acid) was shown Co2+ < Ni2+ < Cu2+ > Zn2+ as same as the order of Irving-Williams series. The stability constants of Ce3+, Eu3+, Gd3+, and Yb3+ trivalent lanthanide metal ion complexes of N3O2-tri(methylacetic acid) were, respectively, 11.26 for Ce3+, 11.56 for Eu3+, 11.49 for Gd3+, and 11.80 for Yb3+. The values of the stability constants on trivalent metal ions with the ligand are increasing according to increase atomic number, due to increase acidity. But the value of stability constant of Gd3+ ion is less than the value of Eu3+ ion. This disordered behavior is also reported by Moeller.

• Proceedings of the Materials Research Society of Korea Conference
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• 2003.11a
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• pp.229-229
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• 2003

Enhancement of the exchange bias and optimization of the structure have been the focus that many researchers studied, recently [1]. In this report, magnetic properties of MTJs with structure of Si/Ta (5)/Cu (10)/ Ta (5)/ Ni$\sub$80/Fe$\sub$20/ Cu (5)/ Mn$\sub$75Ir$\sub$25/ (10)/ Co$\sub$70/Fe$\sub$30/ (2.5)/ Al-O (1.5)/ Co$\sub$70/Fe$\sub$30/ (2.5)/ Ni$\sub$80/Fe$\sub$20/ (t)/ Ta (5) (t=0,10, 30, 60 and 100 nm, respectively) were investigated. The relationship between the structure and magnetic parameters of interfacial exchange coupling and interlayer coupling in as-deposited and annealed junctions was studied. The temperature dependence of exchange coupling was considered.

• Journal of the Korean earth science society
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• v.32 no.7
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• pp.707-718
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• 2011

We study the natural background and geochemical characteristics on geological groups of stream sediment in the Boseong-Hwasun area. We collected 186ea stream sediment samples along the primary channels and dried them naturally in laboratory. The contents of major, trace and rare earth elements were determined by XRF, ICP-AES and NAA analysis methods. In order to know the natural background and geochemical characteristics of geological groups, we classified the studied area into granitic gneiss (GGn) area and porphyroblastic gneiss (PGn) area. The contents range of major elements for GGn area is $SiO_2$ 45.5-73.09 wt.%, $Al_2O_3$ 12-20.76 wt.%, $Fe_2O_3$(T) 3.72-8.85 wt.%, $K_2O$ 2.38-4.2 wt.%, MgO 0.75-2.77 wt.%, $Na_2O$ 0.78-1.88 wt.%, CaO 0.27-2.1 wt.%, $TiO_2$ 0.56-1.72 wt.%, $P_2O_5$ 0.06-0.73 wt.% and MnO 0.03-0.95 wt.%, and for PGn area it is $SiO_2$ 43.74-70.71 wt.%, $Al_2O_3$ 11.54-25.05 wt.%, $Fe_2O_3$(T) 3.44-13.46 wt.%, $K_2O$ 2.08-3.86 wt.%, MgO 0.65-2.99 wt.%, $Na_2O$ 0.63-1.7 wt.%, CaO 0.35-2.07 wt.%, $TiO_2$ 0.68-4.17 wt.%, $P_2O_5$ 0.1-0.31 wt.% and MnO 0.07-0.33 wt.%. The contents range of hazard elements for GGn area is Cr 41.7-242 ppm, Co 7.6-25.1 ppm, Ni 12-61 ppm, Cu 10-47 ppm, Zn 48.5-412 ppm, Pb 17-215 ppm, and for PGn area, it is Cr 29.6-454 ppm, Co 5.9-53.7 ppm, Ni 8.7-287 ppm, Cu 6.4-134 ppm, Zn 43.6-370 ppm, Pb 15-37 ppm area. There is a good correlation between Cr and MgO and Co among $Al_2O_3$, $Fe_2O_3$(T), MgO and Ni among $Fe_2O_3$(T), CaO, MgO whereas Cu, Zn and Pb have a low correlation for major elements in GGn area. Generally Cr, Co, Ni, and Cu have a good correlation with major elements, but a low correlation with Zn and Pb in PGn area.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.24 no.2
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• pp.70-76
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• 2014

$Zn_2TiO_4$, using an anatase form of $TiO_2$ on zinc crystalline glaze, was shown as effective nuclear agent. Thus the effects on glaze were studied with synthesized $Zn_2TiO_4$ at low temperature. First, the chromophore elements were employed in synthesized $Zn_2TiO_4$ then add them in the zinc crystalline glaze. Crystal creation and development of color by $Zn_2TiO_4$ addition on the zinc crystalline glaze were more effective. Addition of $Zn_2TiO_4$, which is developed in low range temperature, is effected as zinc crystalline nuclear in the willemite glaze. When 5 wt% of synthesized $Zn_2TiO_4$ was added to the willemite glaze, nuclear creation increases and steadily retains. Therefore addition of respectively doped $Zn_2TiO_4$ with CoO, NiO, and CuO would increase doped effects in the glaze, various color willemite crystal were obtained.