• The Journal of the Petrological Society of Korea
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• v.20 no.4
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• pp.207-217
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• 2011

Here we report major element composition, trace and rare earth element abundance, Sm-Nd and Rb-Sr isotopic composition from Deokgu leucogranite. Chondrite-normalized REE pattern and its Eu anomaly are divided into 3 types systematically, and have close relationship with $SiO_2$ contents. Such geochemical characteristic indicates that the leucogranite was derived by feldspar fractionation from a common source magma. Sm-Nd and Rb-Sr whole rock ages are $1,785{\pm}180Ma$ (initial $^{143}Nd/^{144}Nd\;ratio=0.51003{\pm}0.00016,\;2{\sigma}$; ${\varepsilon}_{Nd}(T)=-5.9$) and $1,735{\pm}260Ma$ (initial $^{87}Sr/^{86}Sr\;ratio=0.702{\pm}0.046,\;2{\sigma}$), respectively. Initial ${\varepsilon}_{Nd}$ value indicates that the magma should be derived from the crustal material. This initial ${\varepsilon}_{Nd}$ value also corresponds well with those from the Precambrian granitoids from North-China Craton rather than those of South-China Craton.

• Korean Journal of Optics and Photonics
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• v.14 no.5
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• pp.515-520
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• 2003

Characteristics of an amplifier with repetition rate of a few KHz is investigated. The continuous flash lamp pumped Nd:YAG laser head is used as an amplifier. The thermally induced birefringence of the laser medium is compensated and the depolarization is reduced to 5% in a double-pass amplifier. The amplification factor of a four pass amplifier reaches to about 3.2 at the repetition rate 5-10 KHz and the pulse width is lengthened from 40 ns to 48 ns.

• Proceedings of the Korean Vacuum Society Conference
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• 2000.02a
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• pp.59-59
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• 2000

Recently low resistance of bus line is required for large screen size TFT-LCD panels. As a result, lower resistance Al-alloy is currently reviewed extensively. The resistivity is required smaller than 10 $\mu$$\Omega$cm. In this paper, Al-Nd thin film were deposited on glass substrates by D.C. magnetron sputtering system under various condition. Its properties were characterized by SEM, AFM, XRD, 4-ping-probe. The optimal condition of Al-Nd was 12$0^{\circ}C$, 125W, 0.4Pa, 30sccm(Ar) and 35$0^{\circ}C$, 20min. annealing. At that condition the resistivity of Al-Nd(2wt.%) was about 4 $\mu$$\Omega$cm. The minimum contact resistance of ITO/Nd was about 110$\mu$$\Omega$cm in the condition of 30$0^{\circ}C$, Ar 30 sccm. O2.

• Journal of the Korean Magnetics Society
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• v.1 no.1
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• pp.6-11
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• 1991

In order to investigate electronic and magnetic properties of permanent magnets, we have performed self-consistent electronic structure calculations on compounds of rare-earth and transition metals, such as $SmCo_{5},\;NdB_{6},\;NdFe_{5},\;NdFe_{4}B$. Employing the local density LMTO(linearized muffin tin orbital) band method, we have obtained the ground state parameters, such as band structures, density of states, Stoner parameters, and magnetic moments. We have also investigated interactions between d,f-electrons of Nd, Sm rare-earths and d-electrons of Fe, Co transition metals, and the s,p electrons of boron and explored effects of such interactions on the bonding mechanism and the electronic and magnetic structures in these rare-earth compounds.

• Korean Journal of Optics and Photonics
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• v.3 no.4
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• pp.222-226
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• 1992

The lasing characteristics of a Nd:phosphate glass laser pumped by 514 nm of an $Ar^{+}$ laser has been investigated. The oscillator consists of a Nd:glass gain medium set at Brewster angle, and two concave mirrors, and a flat mirror with a reflectance of 98%. The $Ar^{+}$ laser pumping beam is focused longitudinally at the beam waist of laser mode for efficient pumping. The pumping beam is chopped at 100 Hz to reduce the heat loading to prevent the thermal damage of the gain medium by the latent heat from the absorbed pumping beam. The maximum laser output power of 70 mW at 1.5 W pumping and the threshold input power of 520 mW have been obtained.

• Journal of Magnetics
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• v.7 no.4
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• pp.127-131
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• 2002

HDDR characteristics and magnetic properties of $Nd_{15}{(Fe_{1-x}Co_{x})}_{77}B_{8}$(x=0-0.6) alloys were investigated. The effect of applying magnetic field during the recombination step on the anisotropic nature of the HDDR-treated material was also examined. The $Nd_{15}{(Fe_{1-x}Co_{x})}_{77}B_{8}$ phase in the Nd-Fe-B alloys with high Co-substitution alloy had remarkably enhanced phase stability. The $Nd_{15}{(Fe_{1-x}Co_{x})}_{77}B_{8}$(x=0-0.6) alloys with high Co-substitution could be HDDR-treated successfully by only using high pressure hydrogen. However, these alloys had no appreciable coercivity. The poor coercivity of the HDDR-treated $Nd_{15}{(Fe_{1-x}Co_{x})}_{77}B_{8}$(x=0-0.6) alloys with high Co-substitution was attributed to the $Nd{(Fe,Co)}_2$ phase in the alloys. The magnetic filed applied during the recombination step had little effect on the anisotropic nature of the HDDR-treated powder.

• Proceedings of the Materials Research Society of Korea Conference
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• 2000.11a
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• pp.67-67
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• 2000

• Korean Journal of Poultry Science
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• v.11 no.1
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• pp.49-64
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• 1984

During the 1978-79 Newcastle disease (ND) epizootic period, a detailed survey was conducted on the five representative farms which had been following one of the recommended vaccination programs. When the disease broke out during laying period, clinical symptoms were mild to moderate respiratory distress and greenish diarrhea. Affected flocks experienced weekly mortality from less than 1% to 17%. Egg production returned to normal 18 to 36 days after the initial signs appeared although some flocks never returned to normal. On postmortem examination,, most affected chickens showed severe hemorrhagic lesions in the duodenum, hematoma on ova, and heavy fat accmulation on various visceral organs. Most of the NO affected flocks had geometric mean hemagglutination inhibition antibody(HIA) titers of 7 log$_2$ or higher two to three weeks after the appearance of clinical signs. These HIA titers were at least 16-fold higher than those before infection. Flock mean HIA titers before infection were usually lower than 3 log$_2$. Severity of clinical signs and anamnestic antibody response were maximum in the flocks whose vaccination immunity was insufficient or waned considerably. Observations showed that even young birds, if properly vaccinated, could get effective protection from field ND exposure.

• Journal of Food Hygiene and Safety
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• v.25 no.3
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• pp.245-250
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• 2010

The post-harvest concentration change of four kind of pesticides, captan, chlorpyrifos, methidathion and kresoxim-methyl was investigated with the storage period for the import fruit. Then the post-harvest concentration was set to 1000, 250, 400 and 157 $mgkg^{-1}$ for captan, chlorpyrifos, methidathion and kresoxim-methyl respectively. In case of captan, 0.9-12.5 $mgkg^{-1}$ in total fruit base and ND-0.23 $mgkg^{-1}$ in the sarcocarp were measured after atomization and 0.7-3.2 $mgkg^{-1}$ in total fruit base and ND-0.67 $mgkg^{-1}$ in the sarcocarp were measured after four week. For chlopyrifos, menthidathion, and kresoxim-methyl 0.4-2.2, 0.7-3.1 and 1.3-2.1 $mgkg^{-1}$ in total fruit base and ND-0.32, ND-0.05 and ND-0.16 $mgkg^{-1}$ in the sarcocarp were measured after atomization respectively. After four week 0.3-0.9, 0.4-2.0 and 1.3-1.8 $mgkg^{-1}$ in total fruit base and ND-0.02, ND-0.05 and ND-0.15 $mgkg^{-1}$ in the sarcocarp were investigated for other three pesticides. The concentration decreasing ratio of pesticides was largest for captan, 52% and other components were in order of chlopyrifos, menthidathion, and kresoxim-methy, 47, 41, 11% each other.

• Korean Journal of Optics and Photonics
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• v.9 no.4
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• pp.231-235
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• 1998

Passively Q-switched, laser diode(LD) end-pumped Nd:YAG laser was demonstrated by using $Cr^{4+}$:YAG as a saturable absorber. In addition , we could calculate an excitation efficiency, which is an important parameter to evaluate the pumping geometry, directly by measuring the absorbed power in Nd:YAG at threshold condition. We found that output parameters such as average power, pulse duration, and repetition rate strongly depended on the low intensity transmission of $Cr^{4+}$:YAG and driving current of lase diode. The maximum Q-switched output power of 1 W was obtained with 40 kHz repetition rate. The pulse duration was varied from 50 ns to 200 ns.