• Safe Food
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• v.6 no.3
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• pp.11-16
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• 2011

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2010.06a
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• pp.313-313
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• 2010

$BiFeO_3$ (BFO), when forming a solid solution with $BaTiO_3$ (BTO), shows structural transformations over the entire compositional range, which not only gives a way to increase structural stability and electrical resistivity but also applies a means to have better ferromagnetic ordering. In this respect, we have prepared and studied 0.8 BFO-0.2 BTO thin films on Pt(111)/$TiO_2/SiO_2$/Si substrates by pulsed laser deposition. Various deposition parameters, such as deposition temperature and oxygen pressure, have been optimized to get better quality films. Based on the X-ray diffraction results, thin films were successfully deposited at the temperature of $700^{\circ}C$ and an oxygen partial pressure of 10mTorr and 330mTorr. The dielectric, ferroelectric, and magnetic properties have then been characterized. It was found that the films deposited under lower and higher oxygen pressure corresponded to lower leakage current. Magnetism measurement showed an induced ferromagnetism. The microstructures associated with the magnetic and dielectric properties of this mixed-perovskite solid solutions were observed by transmission electron microscopy, which revealed the existence of complicated ferroelectric domains, suggested that the weak spontaneous magnetization was closely associated with the decrease in the extent of rhombohedral distortion by a partial substitution of $BaTiO_3$ for $BiFeO_3$.

• Proceedings of the Materials Research Society of Korea Conference
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• 1994.05a
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• pp.24-25
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• 1994

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.14 no.12
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• pp.1001-1007
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• 2001

In this study, high dielectric materials, (Pb,La)Ti $O_3$ thin films were fabricated by PLD (Pulsed Laser Deposition) method and investigated in terms of structural and electrical characteristics in order to develope the dielectric materials for the use of new capacitor layers of Giga bit-level DRAM. The deposition conditions were examined in order to fabricate uniform thin films through systematic changes of oxygen pressures and substrate temperature. The uniform thickness and smooth morphology of (P $b_{0.72}$L $a_{0.28}$)Ti $O_3$ thin films were obtained at the conditions of substrate-target distance 5.5[cm], laser energy density 2.1[J/$\textrm{cm}^2$], oxygen pressure 200[mTorr] and substrate temperature 500[$^{\circ}C$]. After the (P $b_{0.72}$L $a_{0.28}$)Ti $O_3$ thin films were fabricated under the above conditions, they were post-annealed by RTA process in order to increase the dielectric constant. The film thickness of 1200 [$\AA$] had dielectric constant 821. Assuming that operating voltage is 2V, leakage current density of (P $b_{0.72}$L $a_{0.28}$)Ti $O_3$ thin films would result into 10$^{-7}$ [A/$\textrm{cm}^2$] and satisfied the specification of 256M DRAM planar capacitor, 4$\times$10$^{-7}$ [A/$\textrm{cm}^2$]m}^2$]

• Journal of Oral Medicine and Pain
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• v.22 no.1
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• pp.125-135
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• 1997

The Author examined the clinical and histological changes on the dorsal tongue mucosa of the adult rats after lasing by pulsed Nd:YAG laser and incising with scalpel. The dorsal tongue was lased through 320$\mu\textrm{m}$optic fiber moving 2.5mm/second to make linear incision 5mm. The five conditions of lasing were three application with 1.0W, 1.75W, 3.0W and 3.0W under saline cooling, and single application with 3.0W at 20Hz. With scalpel, linear incisions through the surface epithelium were performed to 5mm in length. After observing the clinical changes of the incised wounds, the animals were sacrified and the tissues were excised to make the tissue specimens. The stained microscopic tissue slide were observed histologically under the microscope. The following results were obtained : 1. While incision with scalpel causes severe bleeding, lasing does not cause bleeding. 2. In three applications with 1.75W and 20Hz, tissue ablation was limited to areas contacted with optic fiber. 3. In three applications with 3.0W and 20Hz, deep incised wound, extensive destruction of the adjacent epithelium and charring were observed. 4. In three applications with 3.0W and 20Hz under saline cooling, tissue ablation was limite to the superficial mucosa and charring was not observed. 5. In single application with 3.0W and 20Hz, the shape of the incised wound was similar to that of the scalpel incision.

• Journal of the Korean GEO-environmental Society
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• v.12 no.10
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• pp.51-56
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• 2011

This study was conducted to investigate the applicability of pulsed electric field (PEF) treatment for the prevention of scaling formation and membrane fouling reduction. To validate the effect of PEF and to identify the mechanism, some experiments with and without PEF treatment were carried out. PEF treatment affected the precipitation of $CaCO_3$ by which $CaCO_3$ particles were actively grown and sedimented. It was confirmed that the calcium ions were decreased as 78% and particle size was grown by PEF treatment. It was also verified that the crystalline structure of $CaCO_3$ was transformed by PEF treatment from Aragonite, which is formed at a high temperature and hard to be removed, to Calcite being stable at room temperature. In PEF treatment, permeate volume and permeation flux were greater than that of without PEF, case while Langelier Index(LI) decreased. From the experiment results, PEF treatment is believed to be an effective method to prevent scaling formation and to mitigate $CaCO_3$ fouling as the pretreatment of membrane filtration.

• Korean Journal of Head & Neck Oncology
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• v.17 no.1
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• pp.19-25
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• 2001

Objectives: The clinical efficacy of the color and pulsed Doppler ultrasound with spectral waveform analysis for differentiation of malignant from benign cervical lymphadenopathy was prospectively evaluated in cervical lymphadenopathy. Materials and Methods: Color and pulsed Doppler ultrasound examination was prospectively performed in 32 cervical lymph nodes in 28 patients. These 10 nodes from 10 patients were malignant and 22 nodes from 18 patients were benign, proved by operation, biopsy, and follow-up examination. Another 12 lymph nodes from 12 normal volunteers were evaluated as control group. The peak systolic velocity (PSV), minimal diastolic velocity (MDV) , and resistive indexes (RI) of arterial flows within the 32 lymph nodes were assessed to differentiate the malignant from benign nodes with pulsed Doppler ultrasonography. The results were qualitified with one-way ANOVA and Bonferroni method of multiple comparison. Results: The mean values of PSV of malignant, benign, and control nodes were 38.2(10.1-134)cm/sec, 23.3(9-38.5) cm/sec and 11.8(6.7-18.1) cm/sec, respectively. The mean values of MDV of them were 0.9(-7.5-10.7)cm/sec, 9.7(2.9-18.6)cm/sec and 6.5(3.7-9.3)cm/sec, respectively. However, there was no statistical significance in differentiation of malignant from benign nodes with PSV and MDV. The mean values of RI of malignant, benign, and control nodes were 0.99(0.80-1.30), 0.59(0.46-0.77) and 0.45(0.38-0.50), respectively. RI value of 0.8 is suggestive value for discrimination of malignant from benign lymphadenopathy during examination of color Doppler ultrasound of cervical lymphadenopathy. Conclusion: Color and pulsed Doppler ultrasound examination with spectral waveform analysis may be quite helpful in the differentiation between benign and malignant alterations of cervical lymph nodes.

• ETRI Journal
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• v.26 no.3
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• pp.257-261
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• 2004

We grew amorphous SiCN films by pulsed laser deposition using mixed targets. The targets were fabricated by compacting a mixture of SiC and $SiC-{Si_3}{N_4}$ powders. We controlled the film stoichiometry by varying the mixing ratio of the target and the target-to-substrate distance. The mixing ratio of the target had a dominant effect on the film composition. We consider the structures of the SiCN films deposited using 30~70 wt.% SiC in the target to be an intermediate phase of SiC and $SiN_x$. This provides the possibility of growing homogeneous SiCN films with a mixed target at a moderate target-to-substrate distance.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.11a
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• pp.11-12
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• 2005

[ $Pb(Zr_{0.48}Ti_{0.52})O_3$ ] (PZT) thin films were deposited on Pt(111)/Ti/$SiO_2$/Si substrates by pulsed laser deposition. In order to study the effect of different laser pulse repetition rate on the dielectric and ferroelectric properties of PZT thin films,2 Hz and 5 Hz of laser pulse repetition rate were selected. We compared the results of XRD pattern, dielectric constant and hysteresis characteristics. From the experimental data, we found that the electrical properties of PZT thin films which grown ar 2 Hz of laser pulse repetition rate were better than those which grown at 5 Hz of laser pulse repetition rate.

• Proceedings of the KIEE Conference
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• 2000.07c
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• pp.1483-1484
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• 2000

Dielectric thin films of PLT(Pb(La.Ti)O3) for the application of highly integrated memory devices have been deposited on Pt/Ti/SiO2/Si substrates in situ by pulsed laser deposition(PLD). We have systematically investigated the variation of grain sizes depending on the condition of post-annealing and the variation of deposition rate. Both in-situ annealing and ex-situ annealing have been compared depending on the annealing time. C-V measurement, ferroelectric properties, leakage current and SEM were performed to investigate the electrical properties and the microstructural properties of Pb(La,Ti)$O_3$ films.