• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1992.11a
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• pp.31-33
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• 1992

This paper is studies the addition effects of $La_2O_3$ on the magnetic properties of Sr ferrite. Compositions were chosen according to the formula $[SrO{\cdot}nFe_2O_3]_{100-x}(La_2O_3)_x$. where n was varied between 5.8~6.1 and x between 0~3. The composition of the best value $(BH)_{max}$=1.48MGOe was n=6(stoichiometric composition) and x=2 at $La_2O_3$ addition. This value was higher than that of ordinary isotropic strontium ferrite.

• Proceedings of the KIEE Conference
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• 1994.07b
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• pp.1257-1261
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• 1994

Phsysical and dielectric properties of $(1-x)CaTiO_3-xLa(Zn_{1/2}Ti_{1/2})O_3$ ceramics were investigated at the temperature range of $25^{\circ}C$ to $80^{\circ}C$ at the frequency of 6 GHz. As increasing addition of the amount of $La(Zn_{1/2}Ti_{1/2})O_3$ to x = 5 mol,Q value was increased due to grain growth and increase of density. For more addition, Q value decreased due to electrical defect. Temperature coefficient of resonant frequency could be controlled by the amount of $La(Zn_{1/2}Ti_{1/2})O_3$, which could be explained by volume mixing rule.

• Journal of the Korean Ceramic Society
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• v.45 no.3
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• pp.157-160
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• 2008

A series of $La_2O_3$-added zincborosilicate glasses was fabricated by systematically varying $La_2O_3$ addition up to 15mol% under the constraint of a ZnO:$B_2O_3$ ratio of 1:2. The degree of water leaching after ball milling of the prepared glasses in water medium was relatively quantified by the change in zinc peak intensity in energy dispersive spectroscopy. 8mol% of $La_2O_3$ was the most efficient addition in inhibiting the glass leaching by water. The role of $La_2O_3$ in inhibiting the leaching was explained in terms of change of structural units in the glass network. When the optimum 8mol% $La_2O_3$-added ZnO-$B_2O_3$ glass was used as sintering aid for $Al_2O_3$, the fabricated alumina-glass composite at $875^{\circ}C$ demonstrated dielectric constant of 6.11 and quality factor of 15470 GHz, indicating the potential of leaching-minimized $La_2O_3-ZnO-B_2O_3$ glass for application to low temperature co-firing ceramic technology.

• Journal of the Korean Electrochemical Society
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• v.1 no.1
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• pp.45-51
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• 1998

[ $AB_2-type$ ] alloy, one kind of hydrogen storage alloys used as an anode of Ni-MH batteries, has large discharge capacity but has remaining problems regarding initial activation, cycle life and self-discharge. This study investigates the effects of Cr-addition and fluorination after La-addition on $Zr_{0.7}Ti_{0.3}V_{0.4}Mn_{0.4}Ni_{1.2}$, composition $AB_2-type$ alloy. EPMA and SEM surface analysis techniques were used and the crystal structure was characterized by XRD analysis. In addition, electrodes were fabricated out of the alloys and characterized by constant current cycling test, electrochemical impedance spectroscopy and potentiodynamic polarization. Cr-addition was found to be effective to cycle life and self-discharge but ineffective to initial activation due to formation of stable oxide film on surface. Fluorination after La-addition to the alloys improved initial activation remarkably due to formation of highly reactive particles on surface.

• Journal of Microbiology
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• v.45 no.3
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• pp.199-204
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• 2007

The objective of this study was to evaluate the effect of soluble carbohydrates (glucose, cellobiose), pH (6.0, 6.5, 7.0), and rumen microbial growth factors (VFA, vitamins) on biohydrogenation of linoleic acid (LA) by mixed rumen fungi. Addition of glucose or cellobiose to culture media slowed the rate of biohydrogenation; only 35-40% of LA was converted to conjugated linoleic acid (CLA) or vaccenic acid (VA) within 24 h of incubation, whereas in the control treatment, 100% of LA was converted within 24 h. Addition of VFA or vitamins did not affect biohydrogenation activity or CLA production. Culturing rumen fungi at pH 6.0 slowed biohydrogenation compared with pH 6.5 or 7.0. CLA production was reduced by pH 6.0 compared with control (pH 6.5), but was higher with pH 7.0. Biohydrogenation of LA to VA was complete within 72 h at pH 6.0, 24 h at pH 6.5, and 48 h at pH 7.0. It is concluded that optimum conditions for biohydrogenation of LA and for CLA production by rumen fungi were provided without addition of soluble carbohydrates, VFA or vitamins to the culture medium; optimum pH was 6.5 for biohydrogenation and 7.0 for CLA production.

• Asian-Australasian Journal of Animal Sciences
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• v.2 no.3
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• pp.533-534
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• 1989

• 한국정보디스플레이학회:학술대회논문집
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• 2005.07b
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• pp.1495-1498
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• 2005

Due to an efficient red emission, $Eu^{+3}$ ions have doped in various host materials. Eu-doped $LaPO_4/LaPO_4$ core/shell nanophosphor which emits red light in visible range, was synthesized by using a solution system. The mean size of the nanoparticle observed by TEM was about 7-8 nm. In this core/shell system, the thickness of $LaPO_4$ shell was optimized on the basis of relative PL emission intensity. In addition, the luminescent properties of $LaPO_4:Eu/LaPO_4$ core/shell particle have been compared with Eu-doped $LaPO_4$ bulk particle and nanoparticle.

• Journal of the Korean Applied Science and Technology
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• v.4 no.2
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• pp.25-30
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• 1987

In order to investigate the effect to antioxygenic substances in Pine Needles on the photooxidation of linoleic acid (linoleic acid 100mg/10ml ethanol) added antioxidants and antioxygenic substances in Pine Needles was irradiated by the tungsten lamp attached with red fitter. The Photo oxidation of linoleic acid (LA) was conformed with Lea method and rhodan method. The following results were obtained: 1. Photooxidation of LA was greatly increased the presence of photosensitizer. However the Photo oxidation of LA without photosensitizer was smoothly increased by the irradiation. 2. The Photo oxidation of LA without irradiation occured quite lately whether photosensitizer was present or absent. 3. Photooxidation of LA under the presence of photosensitizer was inhibited by the addition of $dl-{\alpha}-tocopherol$ and the acetone fraction of methanol extract of Pine Needles but inhibited by BHT. Photooxidation of LA increased gradually as the addition of BHT increased but decreased gradually as that of acetone fraction increased.

• Applied Biological Chemistry
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• v.42 no.3
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• pp.229-234
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• 1999

The effects of linoleic acid(LA, 18 : 2) and/or bovine serum albumin(BSA) on the lipid metabolism in human hepatoma cell line HepG2 cells were evaluated. HepG2 cells were cultured in basal Dulbecco's modified Eagle's(DME) medium(Basal medium), DME medium containing 0.2 mM LA(LA medium), or DME medium containing both 0.2 mM LA and 0.2-1.0% BSA(LA+BSA medium). $[^{14}C]Acetate(0.3\;{\mu}Ci/ml\;medium)$ was added as a radioactive lipid precursor and the cells were incubated for 6 hours. An addition of LA to basal medium resulted in a decrease in the incorporation of $[^{14}C]acetate$ into total cholesterol fraction. In contrast, an addition of BSA to LA-containing medium tended to increase the incorporation of $[^{14}C]acetate$ into total cholesterol. The alteration of cholesterol metabolism in HepG2 cells incubated in LA+BSA medium was attributed by an increase in the incorporation of $[^{14}C]acetate$ into free cholesterol, but not cholesteryl ester fraction. In addition, the secretion of cholesterol was increased by LA+BSA medium, suggesting that BSA stimulates cholesterol secretion. No significant change in the incorporation of $[^{14}C]acetate$ into cellular total lipids was observed among the experimental groups. However, an increased incorporation of $[^{14}C]-labelled$ fatty acid into cellular triacylglycerol and decreased incorporation into phospholipid were observed in cells incubated with LA+BSA medium as compared to those of LA medium. The secretions of $[^{14}C]-labelled$ triacylglycerol, phospholipid, and free fatty acid were also stimulated in HepG2 cells incubated with LA+BSA medium. In conclusion, the present study suggests that in human hepatocytes, LA and BSA influence lipid metabolism, and BSA enhances the secretion of lipids.

• Journal of the Korean Ceramic Society
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• v.31 no.8
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• pp.841-848
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• 1994

The sintering behavior of La-modified PbTiO3 ceramics was investigated in order to improve the poor sinterability of PbTiO3. Addition of La improved the sinterability. It was confirmed that this improvement was due to the decrease in tetragonality ratio c/a of crystal lattice. The variations of dielectric constant and pyroelectric coefficient were measured with temperature. It was observed that with the increase of La content, Curie temperature decreased and dielectric constant at room temperature increased. La-modified PbTiO3 ceramics had smaller pyroelectric figure of merits than those of pyroelectric materials in use. The effects of grain size on dielectric and pyroelectric properties were also investigated. The change of grain size had effect on maximum dielectric constant and pyroelectric coefficient, but is had little effect on pyroelectric figure of merit at room temperature. The closer examination near ferro-paraelectric phase transition temperature revealed that the behavior of phase transition approached a more relaxor character with the increase of La content and the decrease of grain size.