• 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.

• ETRI Journal
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• v.18 no.1
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• pp.15-27
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• 1996

The effects of $Nd_2O_3$ and $TiO_2$ addition on the microstructures and microwave dielectic properties of $BaO-Nd_2O_3-TiO_2$ system were investigated. $BaNd_2Ti_4O_{12}$ or $BaNd_2Ti_{5}O_{14}$ phases were observed for compositions based on BaO/$Nd_2O_3$ = 1 ratio. The compositions deviated from $BaO/Nd_2O_3=1$ ratio were composed of major phases of $BaNd_2Ti_4O_{12}$ or $BaNd_2Ti_5O_{14}$, and the compound of $Nd_2O_3$ and $TiO_2(Nd_2Ti_2O_7)$ or that of BaO and $TiO_2(BaTi_4O_9)$. The microstructure of ceramic with $BaO{\cdot}Nd_2O_3{\cdot}4TiO_2$ composition varied from spherical grains to needlelike grains with increasing sintering temperature. With increasing $Nd_2O_3$, the optimum sintering temperature with maximum density increased, and the dielectric constant(${\varepsilon}_r$) and quality factor(Q) decreased due to the formation of secondary phases. With increasing $TiO_2$, the optimum sintering temperature and the dielectric constant decreased with increased Q value. And the temperature coefficient of resonant frequency, ${\tau}_f$ shifted toward positive direction. The dielectric ceramics with $BaO/Nd_2O_3=1$ showed Q values of above 2000 and dielectric constants of above 80 at 3GHz.

• Korean Journal of Optics and Photonics
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• v.3 no.1
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• pp.37-42
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• 1992

Nd:YLF regenerative amplifiers have proved to be reliable source for producing stable short pulses of high repetition rate. We used a convex-concave mirror design to optimize output energy and stability while minimizing the energy density on critical intracavity optical components. The Kd:YLF laser pulse is used as a seed pulse which has pulse width of 40 ps, energy of 100pJ, and wavelength of 1053 nm. The amplifier yields stable 1 mJ pulses at 3.5 kHz repetition rate, and the maximum energy is measured as 5 mJ.

• Korean Journal of Environmental Agriculture
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• v.15 no.3
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• pp.282-288
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• 1996

Because of the high water content of the household garbage, it is difficult to compost it. Therefore, this study was conducted to investigate the possibility of using coal fly ash as humidity conditioner for the household garbage composting. The summarized results are as follows : 1. The maximum temperatures were $35^{\circ}C$ in spring, $47^{\circ}C$ in summer, and $43^{\circ}C$ in winter during the composting periods. 2. The mass was reduced to 70.5% after 60 days. The average volume reduced down to 74.7% after 60 days. 3. The seasonal variation of pH values showed a similar tendency and reached 8.5 after 60 days. 4. The water content was reduced at an early stage of composting and not much changed thereafter. It had 49.7% in spring, 33.9% in summer, and 56.5% in winter after 60 days. Ash contents were not much changed during the composting periods. 5. The contents of inorganic compounds were in the range of $0.06{\sim}4.03%$ $P_2O_5$, $0.01{\sim}2.87%$ CaO, $0.18{\sim}1.43%$ MgO, and $0.39{\sim}2.03%$ $K_2O$. Heavy metal contents were in the range of $ND{\sim}14.08$ Hg ${\mu}g/kg$, $ND{\sim}0.80$ Cd mg/kg, $4.99{\sim}28.95$ Cu mg/kg, $ND{\sim}242.62$ Cr mg/kg, $ND{\sim}20.24$ Pb mg/kg, and $ND{\sim}59.87$ Zn mg/kg.

• The Korean Journal of Malacology
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• v.29 no.4
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• pp.335-341
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• 2013

The seven mitochondrial DNA regions (ND2, ND5, ND4, ND4L, ND6, ND1 and 12SrRNA) of Haliotis discus hannai were examined to estimate the availability as a genetic marker for the study of population genetic. The region with the highest genetic variation was ND4 (Haplotype diversity = 1.0000, Nucleotide diversity = 0.0108). On the other hand, ND2 and ND1 regions have significantly appeared genetic divergence between clusters (divergence of 90% and 87%). Also, pairwise $F_{ST}$ between clusters within ND2 and ND1 regions showed high values; 0.4061 (P = 0.0000), 0.4805 (P = 0.0000) respectively. Therefore we can infer that it is the most efficient and accurate way to analyze the region of ND4 with the highest variation in addition to the regions of ND2 and ND1, which formed clusters with high bootstrap value, for study of population genetic structure in this species.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.06a
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• pp.243-243
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• 2007

We have studied the electrical properties and microstructure of $(Y_{0.5}Nd_{0.25}Sm_{0.25})Ba_2Cu_3O_y[(YNS)-123]$ Oxides by rod-type seeded melt growth process(RSMG) in air atmosphere. Rod-type $NdBa_2Cu_3O_y${Nd-123) seed crystals made a extrusion process method, were used for achieving the ab-plane alignment having large grains perpendicular to the center of (YNS)-123 samples. The observations using SEM and TEM micrographs of the melt-textured (YNS)-123 samples revealed that the nonsuperconducting $(Y_{0.5}Nd_{0.25}Sm_{0.25})Ba_2Cu_3O_y[(YNS)-211]$ inclusions are uniformly distributed in the superconducting matrix. The microstructure and electrical properties were investigated by XRD, SEM, TEM and DC SQUID magnetometer. The sample showed a sharp superconducting transition at 90 K. The magnetization values of the (YNS)-123 sample exhibited the enhanced electrical properties, compared with $YBa_2Cu_3O_y$(Y-123) sample.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.07a
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• pp.195-196
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• 2005

In recent years, as the needs of MOS's a high quality is desired to get the superior electrical characteristics and reliability on MOSFET. As an alternative gate dielectric have drawn considerable alternation due to their superior performance and reliability properties over MOSFET, 2'nd silicidation formation process has been proposed as a dielectric growth/annealing process. In this study the author observed process characteristics on MOS structure. In view points of the process characteristics of MOS capacitor, the oxygen & polysilicon was analyzed by SIMS analysis on l'st & 2'nd Ti process, the oxygen and Si2 contents[Count/sec] of 1.5e3 & 3.75e4 on l'st process and l.1e3 & 2.94e4 on 2'nd process, the Ti contents' of 8.2e18 & 6.5e18 on 1'st and 2'nd process. The sheet resistance[$\Omega/sq.$] was 4.5 & 4.0, the film stress[dyne/cm 2] of 1.09e10 & 1.075e10 on l'st and 2'nd process. I could achieved the superior MOS characteristics by 2'nd silicidation process.

• KIEE International Transactions on Electrophysics and Applications
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• v.5C no.6
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• pp.251-256
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• 2005

Directionally melt-textured high $T_c\;(Y_{0.5}Nd_{0.25}Sm_{0.25})Ba_{2}Cu_{3}O_y$ [(YNS)-123] superconductor was systematically investigated by the zone melt growth process in air. A sample prepared by this method showed well-textured microstructure, and $(Y_{0.5}Nd_{0.25}Sm_{0.25})_{2}BaCuO_5$[(YNS)211] inclusions were uniformly dispersed in large $(Y_{0.5}Nd_{0.25}Sm_{0.25})Ba_{2}Cu_{3}O_y$ [(YNS)123] matrix. High irreversibility field and magnetization hysteresis loop of the zone melt-textured (YNS)-123 sample exhibited the enhanced flux pinning, compared with $YBa_{2}Cu_{3}O_y$ (Y-123) sample without RE(rare earth). Critical current density of (YNS)-123 sample was $2.5{\times}10^4\;A/cm^2$ at 2 T and 77 K.

• Korean Journal of Materials Research
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• v.20 no.3
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• pp.142-147
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• 2010

Nano-sized $BaNd_2Ti_5O_{14}$ powders were prepared by the spray pyrolysis process. Sucrose used as the organic additive enabled the formation of nano-sized $BaNd_2Ti_5O_{14}$ powders. The powders prepared from the spray solution without sucrose had a spherical shape, dense structure and micron size before and after calcination. However, the precursor powders prepared from the spray solution with sucrose had a large size, and hollow and porous morphology. The precursor powders had an amorphous crystal structure because of the short residence time of the powders inside the hot wall reactor. The complete decomposition of sucrose did not occur inside the hot wall reactor. Therefore, the precursor powders obtained from the spray solution with sucrose of 0.5M had a carbon content of 39.2wt.%. The powders obtained from the spray solution with sucrose of 0.5M had a slightly aggregated structure of nano-sized primary powders of $BaNd_2Ti_5O_{14}$ crystalline phase after calcination at $1000^{\circ}C$. The calcined powders turned into nano-sized $BaNd_2Ti_5O_{14}$ powders after milling. The mean size of the $BaNd_2Ti_5O_{14}$ powders was 125 nm.

• Journal of Periodontal and Implant Science
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• v.26 no.1
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• pp.293-308
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• 1996

Recently, dental laser have been applied for removal of soft tissues, hemostasis and blood coagulation, removal of benign and malignant tumor, treatment of leukoplakia, aphthous ulcer and herpetic lesion, implant second surgery, removal of granulation tissue, frenectomy, clinical crown lengthening, gingivectomy, gingivoplasty, and treatment of dentin hypersensitivity. Even though the frequency of laser treatment is increasing, the research on the healing process after gingivectomy using pulsed Nd : YAG laser is very rare. The purpose of this study was to observe and compare the wound healing after gingivectomy using scalpel and pulsed Nd : YAG laser in the rat. Gingivectomy was performed using pulsed Nd : YAG laser(SUNRISE Technologies, U.S.A., 1.5 Watts, 10 pps) on the buccal gingiva of right maxillary first molar and using scalpel(No.12) on the contralateral side. Those sites treated by surgical scalpel were designated as the control, and by pulsed Nd : YAG laser as the experimental group. Animals were sacrificed at 1, 2, 3, 5, 7, 11 and 14 days postoperatively, and specimens were histologically observed under light microscope. The results were as follows : 1. Clinical observation Normal color and shape were observed at the 5th day ill the control group and the 7th day in the experimental group. 2. Histologic findings 1) In the control group, denser inflammatory infiltration was observed. 2) Epithelialization started at the 2nd day in the control group, similar to the experimental group, and completed at the 11th to the 14th day postoperatively. 3) In the experimental group, connective tissue showed the vacuole formation and degenerative change during early healing period. Healing of connective tissue was slower in the experimental group than in the control group by 2 days. 4) In the both groups, wound healing was completed at the 2nd week. From this study, gingivectomy using pulsed Nd : YAG laser seems to result in a little delayed wound healing process, compared to the gingivectomy using scalpel. Considering the clinical advantages of laser surgery, pulsed Nd : YAG laser might be useful device for gingivectomy.