• Korean Journal of Materials Research
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• v.9 no.1
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• pp.3-7
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• 1999

The change of phosphorescent property with chemical modification and co-doping of Nd as an auxiliary activator in CaAl$_2$$O_4$: Eu\ulcorner, Nd\ulcorner phosphor, employing Nd\ulcornerion(0.6%) and an co-activator maintained its afterglow for 4.5 hours. And also the initial persistent brightness and phosphorescent property were further improved both by substituting Al by B atoms and incorporation of Nd\ulcorner ion. It was found that the persistent time was 30 hours for&Ca(Al_{0.97}\;B_{0.03}) $_2$$O_4$:EU\ulcorner(0.3%), Nd\ulcorner(0.6%) phosphor.

• Journal of Magnetics
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• v.4 no.2
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• pp.39-45
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• 1999

Sandwich structures of$ Nd_2Fe_{14}B/Fe/Nd_2Fe_{14}B $magnetic films have been grown by a KrF excimer laser (λ=248 nm) ablation technique. Magnetic properties were characterized by varying the thickness of hard ($Nd_2Fe_{14}B$) and soft (Fe) magnetic films and the volume fraction as well. In the (x)nm[NdFeB]/(y)nm[Fe]/(x)nm[NdFeB]/(100) Si structure the thickness (x) was varied from 3.6 to 54 nm, and (y) from 15 to 112 nm. At (y) = 15~20 nm where the volume fraction of Fe corresponded to 61~75%, the sandwich structure exhibited an enhanced Mr/Ms and iHc as well from the result of the exchange coupling between the magnetic layers. Experimentally calculated exchange constant$ (A_s) of A_s = 2.5{\times}10^{-10} J/m$ was estimated using the intrinsic coercivity (iHc) of 1.2 kOe at 5 K for the sandwich magnetic trilayers.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.12 no.1
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• pp.50-55
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• 2002

$Nd_2O_3$0.2~0.5 wt.% doped $LiNbO_3$single crystals were grown by the Czochralski method. The ZnO doping by 2~8 mole% can improve the resistance of optical damage. In this study, Nd : LiNbO$_3$ single crystals with the periodical domain structure were obtained by CZ method.

• Journal of Preventive Medicine and Public Health
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• v.23 no.1 s.29
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• pp.57-64
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• 1990

Since the reservoir of leptospires organism is consisted of a broad spectrum of animals, the best method of prevention is vaccination. The clinical trial of leptospires vaccine conducted on human volunteer for its immunogenicity and safety. Summarized results are as following : 1. The Oral temperature among vaccinated group ranged from $36.7{\pm}0.46^{\circ}C\;to\;37.0{\pm}0.34^{\circ}C$, while in placebo injected group it ranged from $36.4{\pm}0.46^{\circ}C\;to\;36.7{\pm}0.53^{\circ}C$. There was no association between vaccination and fever (p>0.05) 2. Mild local reactions revealed in vaccinees were swelling (50-75% ), Redness($75{\sim}90%$), and induration ($25{\sim}40%$). Placebo injected group revealed only redness in 12.5% in 1st injection and 37.5% in second injection. The duration local reactions on injection site for th vaccinees and place groups disappeared within 48 hours. 3. Generalized Symptoms complained by the vaccinees were myalgia (25%), back pain(15%), headache (15%), pruritus(15%), and abdominal pain(10%), whereas placebo group complained of headache (25%), myalgia(12.5%), back pain(12.5%), pain in eyes(12.5%), abdominal pain(12.5%) pruritus (12.5%) and nausea(12.5%). 4. The serological test(MAT) of vaccinees showed geometric mean antibody titer as follows : a. L. icterohemorrhagiae lai 1 week after 1st vaccination : 22.45 1 week after 2nd vaccination : 111.23 3 week after 2nd vaccination : 266.64 b. L. canicola canicola 1 week after 1st vaccination : 24.62 1 week after 2nd vaccination : 123.92 3 week after 2nd vaccination : 276.55 c. L. icterohemorrhagiae copenhageni 1 week after 1st vaccination : 28.28 1 week after 2nd vaccination : 128.55 3 week after 2nd vaccination : 247.88 Whereas all of the place injected group showed below 1:20 titers. The sero-conversion rate of vaccinees were 100 percent.

• Journal of Magnetics
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• v.4 no.2
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• pp.46-51
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• 1999

A solid-HDDR characteristics of the Nd-Fe-B-type alloys magnetic properties of the solid-HDDR treated materials have been investigated using three types of alloys; $Nd_{15}Fe_{77}B_8 (alloy A), Nd_{16}Fe_{75.9}B_8Zr_{0.1}(alloy B), and Nd_{12.6}Fe_{68.7}Co_{11.6}B_8Ga_{1.0}Zr_{0.1} $(alloy C). It has been found that the four-components alloy B and six-components alloy C have showed higher hydrogenation temperatures than the ternary alloy A. The alloys A and B appeared to absorb more hydrogen gas more rapidly as well compared to the alloy C. The disproportionation temperature of hydrogenated materials was exhibited no significant difference among the alloys. The thermal stability of the hydrided materials of the three types of alloys was found to become more stable in order of number of components. The disproportionation and the recombination kinetics were significantly sluggish in the solid-HDDR manner with respect to the conventional manner. Some degree of anisotropic nature was found to exist in the ingot and this anisotropic nature was retained even after the solid-HDDR treatment. It was suggested the solid-HDDR treatment may possibly be used for a preparation of an isotropic or anisotropic Nd-Fe-B-type cast magnets.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.12 no.1
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• pp.57-61
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• 1982

The author has made a study on the classification of the mandibular 3rd molars of Korean youths through dental radiography by means of Pell & Gregory's classification and on the prevalence of the dental caries of distal surface of the mandibular 2nd molar adjacent to the mandibular 3rd molars turned anteriorly. The results are as follow; 1. It was found that the largest case number was class I (272 cases, 52.9%) in the relation of the tooth to the ramus of the mandible and 2nd molar. 2. The mesio-angular position was the largest number (239 cases, 46.5%) in the relation of the long axis of the impacted mandibular 3rd molar to the long axis of the 2nd molar. 3. The mesio-angular position of class I was the largest number (140 cases, 27.2 %) in the relation of the tooth to the ramus of the mandible and 2nd molar and the long axis of the impacted mandibular 3rd molar to the long axis of the 2nd molar. 4. The average angle of the long axis of mandibular 3rd molar in mesioangular position or horizontal position to the occlusal plane was 143° 5. Mandibular 3rd molar with lesion such as dental caries or pericoronitis was 73 cases (14.2). 6. The caries incidence rate of the distal surface of the 2nd molar was about 3.1%.

• Journal of the Korean Institute of Telematics and Electronics
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• v.20 no.6
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• pp.23-28
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• 1983

Two measures of similarity between contours, the 1 st-order similarity measure and the 2nd-order similarity measure are proposed. They are based on the residual errors of the least squares fit. In particular, the 2nd-order similarity measure has a good reliability with respect to contours of many variations such as imperfection, affine transform or combination of these properties. By taking experiments of aircraft identification and recognition we show that in the matching performance the 2nd -order similarity measure is superior not only to the 1 st-order similarity measure but also to the previous matching techniques.

• Applied Chemistry for Engineering
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• v.28 no.6
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• pp.720-725
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• 2017

M(10)-Ni(5)/SBA-15(M=Ce, Nd, Sm) catalysts were prepared for the partial oxidation of methane (POM) to syngas. The catalysts were characterized by BET, TEM, and XPS. The BET-specific surface area and average pore size for M(10)-Ni(5)/SBA-15(M=Ce, Nd, Sm) were 538.8, 504.3, and $447.3m^2/g$ and 6.4, 6.8, and 7.1 nm, respectively. TEM results showed that the mesoporous hexagonol structure was formed for SBA-15, while the homogeneous dispersion of Ni and Ce particles on the surface was formed for Ce(10)-Ni(5)/SBA-15 caused by the confinment effect of SBA-15. XPS data confirmed that $Ce^{4+}$ and $Ce^{3+}$ on the surface catalyst have two oxidation states due to the lattice oxygen species ($O^{2-}$, $O^-$). The yields of POM to syngas over Ce(10)-Ni(5)/SBA-15 were 52.9% $H_2$ and 21.7% CO at 1 atm, 973 K, $CH_4/O_2=2$, $GHSV=1.08{\times}10^5mL/g_{cat.}{\cdot}h$, and these values were kept constant even after 75 h on streams. The same tendency of syngas yields was observed for M(10)-Ni(5)/SBA-15(M=Ce, Nd, Sm). These results confirm that the redox reaction of promoters including Ce, Nd, and Sm enhanced the stability and yield of catalysts.

• Korean Journal of Food Science and Technology
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• v.36 no.6
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• pp.872-878
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• 2004

Food products selected based on their annual sales and international acrylamide research data were analyzed for quantitation of acrylamide. Samples including raw food, substitute meal, snack, drink, and sauce products were analyzed by LC/MS/MS methods adopted by PDA. Upon comparison, concentrations of acrylamide in these products were similar to those analyzed in other countries.

• Nuclear Engineering and Technology
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• v.38 no.3
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• pp.301-310
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• 2006

Destructive methods were used for the burnup determination of U-Zr alloy nuclear fuel irradiated in the High-flux Advanced Neutron Application Reactor (HANARO) at KAERI. The dissolution rate of unirradiated U-Zr alloy fuel in $HNO_3$/HF mixtures was investigated for the experimental conditions of a different temperature, and initial concentrations of HF and $HNO_3$. The irradiated U-Zr alloy fuel specimen was dissolved in a mixed acid condition of 3 M HNO3 and 1 M HF at $90^{\circ}C$ for 8 hours under reflux. The total burnup was determined from measurement of the Nd isotope burnup monitors. The method includes U, Pu, $^{148}Nd,\;^P{145}Nd+^{146}Nd,\;^{144}Nd+^{143}Nd$ and total Nd isotopes determination by the isotope dilution mass spectrometric method (IDMS) using triple spikes $(^{233}U,\;^{242}Pu\;and\;^{150}Nd)$. The effective fission yield was calculated from the weighted fission yields averaged over the irradiation period. The results are compared with that obtained by the destructive -spectrometric measurement of the $^{137}Cs$ monitor.