• Restorative Dentistry and Endodontics
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• v.16 no.2
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• pp.143-154
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• 1991

The purpose of this study was to evaluate the sealing ability of five obturation methods in conjunction with sealer. Fifty extracted upper and lower anterior teeth were selected and the access cavities were prepared lingually with a round bur. The working length was determined with a #15K file, and the root canals were instrumented with a #40K file 1mm short of the apical foramen. The apical third of root canal was flared by step-back technique and the coronal two thirds of root canal using #2 - 3 Gates Glidden drills. And then, the teeth were randomly assigned to five groups of 10 teeth each. A thin coat of Tubliseal was placed into the canal into the canal using the # 35 reamer and the canals were filled by lateral condensation, vertical condensation, ultrasonic activated lateral condensation, ULTRAFIL injecting, and McSpadden compaction methods. All teeth were stored in 100 % relative humidity at 31c for 48 hours. The roots were suspended in 2 % methylene blue solution for 48 hours, left to dry for 24 hours and then, half side of root was removed longitudinally using the fissure bur. A Boley gauge wes used to measure the distance, to the nearest 0.1mm, from the apical foramen to the most coronal level of dye penetration. The measurement of dye penetration was statistically compared by Duncan's multiple range test The results were as follows 1. Ultrasonic group showed the best sealing ability among the all experimental groups, but there were statistically no significant difference in the sealing ability between ultrasonic group and vertical condensation group. 2. There were no statistically significant difference in the sealing ability among the lateral, vertical, and ultrasonic groups. 3. McSpadden group showed the worst sealing ability among the all exprimental groups.

• Applied Biological Chemistry
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• v.30 no.4
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• pp.340-344
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• 1987

Saponins of ginseng root, leaf and stem were identified by TLC. Eleven unknown spots were detected in ginseng leaf and ten unknown spots in ginseng stem on TLC besides seven ginsenosides such as $ginsenoside-Rg_1,\;-Rf,\;-Re,\;-Rd,\;-Rc,\;-Rb_2,\;and\;-Rb_1$ which are contained in ginseng root. $Ginsenoside-Rg_3\;and\;-Rg_2$ were identified on TLC from mild hydrolysates with 50% acetic acid of total saponins from ginseng root, leaf and stem. Meanwhile, panaxadiol, panaxatriol and oleanolic acid were identified from hydrolysates with 7% ethanolic sulfuric acid of total saponin of ginseng root, while panaxadiol and panaxatriol from those of total saponins of ginseng leaf and stem.

• Journal of the korean academy of Pediatric Dentistry
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• v.45 no.2
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• pp.144-153
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• 2018

The aim of this study was to understand the roles of Sonic Hedgehog (SHH) signaling during tooth root and periodontium formation. In this study, we generated the dental mesenchyme-specific Smoothened (Smo) activated/inactivated mice with the activity of Cre recombinase under the control of osteocalcin promoter. In the Smo activated mutant molar sections at the postnatal 28 days, we found extremely thin root dentin and widened pulp chamber. Picrosirius red staining showed loosely arranged fibers in the periodontal space and decreased cellular cementum with some root resorption. Immunohistochemical staining showed less localization of matrix proteins such as Bsp, Dmp1, Pstn, and Ank in the cementum, periodontal ligament, and/or cementoblast. In the Smo inactivated mutant mouse, there was not any remarkable differences in the localization of these matrix proteins compared with the wild type. These findings suggest that adequate suppressing regulation of SHH signaling is required in the development of tooth root and periodontium.

• JSTS:Journal of Semiconductor Technology and Science
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• v.17 no.2
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• pp.245-251
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• 2017

Niobium doped zirconium oxide (Nb-Zr-O:NZO) thin films were fabricated on Si substrates by a sol-gel technique with an annealing temperatures of $500{\sim}1000^{\circ}C$ in air ($N_2:O_2=3:1$) for 20 minutes. It was found that the NZO film is based on tetragonal $ZrO_2$ polycrystalline structure with the Nb 5+ ion state and there is almost no diffusion of Nb or Zr to Si substrate. The relative dielectric constant for the NZO film with the Nb composition of 30 mol% and annealed at $800^{\circ}C$ was around 40. The root mean roughness was 1.02 nm. In addition, the leakage current of NZO films was as low as $10^{-6}A/cm^2$ at 4.4 V.

• Journal of Industrial Technology
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• v.8
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• pp.23-30
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• 1988

In this paper, the characteristics of electrical breakdown and TDDR (Time Dependant Dielectric Breakdown) were studied to evaluate stability and reliability of thin insulator films such as oxide and nitride. As the oxide film thickness decreased, the electrical breakdown field was increased proportioning to its reverse square root, ${d^{-\frac{1}{2}}}$. As for the temperature dependance of breakdown field, its field was inclined to decrease as temperature increased. It also showed that oxide charge (Qss) was changed by stress field and stress time. Consequently, TDDB characteristics and breakdown mechanism proved the improvement of reliability and stability and provided the accurate analysis to predict a device life time.

• Proceedings of the KIEE Conference
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• 2006.04a
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• pp.108-110
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• 2006

A prediction model of charge concentration of silicon nitride (SiN) thin films was constructed by using neural network and genetic algorithm. SIN films were deposited by plasma enhanced chemical vapor deposition and the deposition process was characterized by means of $2^{6-1}$ fractional factorial experiment. Effect of five training factors on the model prediction performance was optimized by using genetic algorithm. This was examined as a function of the learring rate. The root mean squared error of optimized model was 0.975, which is much smaller than statistical regression model by about 45%. The constructed model can facilitate a Qualitative analysis of parameter effects on the charge concentration.

• Proceedings of the Ginseng society Conference
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• 1974.09a
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• pp.77-93
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• 1974

The sapogenins of two-and four-year-old A-merican ginseng plants (Panax quinquefolium L.) (Araliaceae) collected in July and September were studied. American ginseng saponins (panaquilins) differ from Korean ginseng (Panax ginseng C. A. Meyer) saponins (ginsenosides). The American ginseng saponins separated and named were panaquilins A, B, C, D, E-l, E-2, E-3, G-l, G-2, (c) and (d). One-dimensional thin-layer chromatography did not completely separate panaquilin mixture and were subject to misinterpretation. The panaquilins were more accurately separated and identified by the two-dimensional thin-layer method established. Some differences in American ginseng saponins were dependent upon the plant age, time of collection, and part extracted. The American ginseng sapogenin components are panxadiol (panaquilins B and C), oleanolic acid (panaquilin D) and panaxatriol (panaquilin G-l). The panaquilins E-l, E-2 and E-3 mixture contains both panaxadiol and panaxatriol. The genins of panaquilins A, (c), (d) and G-2 were not identified. In addition, ${\beta}-sitosterol$ and stigmasterol were identified from the root ether extracts.

• Korean Journal of Medicinal Crop Science
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• v.6 no.1
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• pp.38-43
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• 1998

This experiment was carried out to gather basic information for improvement of peeling methods in peony (Paeonia lactiflora) roots which have been used for medicinal resources in Korea. Drying time required was shortened in thin root. Optimum drying time after machine peeling appeared to be 20 hrs in 5 to 10mm of root diameter, 39 hrs in 10 to 15mm, 48 hrs in 15 to 20mm, 56 hrs in more than 20mm, but those of unpeeled roots took 11 hrs in 5mm of root diameter and 4 hrs in exposed parent material. Paeoniflorin content in dried roots after peeling was lower than that of unpeeled root. Paeoniflorin content in root below 5mm in diameter was highest (6.15 %) and that was decreased in the increased root diameter up to 20mm, but it was slightly increased in root greater than 20mm in diameter.

• 한국신재생에너지학회:학술대회논문집
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• 2010.06a
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• pp.94.2-94.2
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• 2010

Indium tin oxide (ITO) Thin films were grown on Non-alkarai glass Substrates by PVD method and Subsequently Subjected to ($100^{\circ}C-350^{\circ}C$) Thermal Annealing (TA) In Nitr Oxygen ambinent. Most of all, The effect of TA treatment on the structural properties were studied by using X-Ray diffraction and atomic force microscopy, while optical properties were studied by UV-Transmittance measurements. After TA treatment, the XRD spectra have shown an effective relaxation of the residual compressive stress, As a result, XRD peaks increase of the intensity and narrowing of full width at half-maximun (FWHM). In addtion The microstructure, The surface morphology, the optical transmittance changed and improved, and we investigated The effects of temperature, Time and atmosphere during the TA on the structural and electrical properties of the ITO/glass on TA at $300^{\circ}C$. As a results, the films are highly transparent (80%～89%) in visible region. AFM analysis shows that the films are very smooth with root mean square surface roughness 0.58nm -2.75nm thickness film. It is observed that resistivity of the films drcreases T0 $1.05{\times}10^{-4}{\Omega}cmt$ $6.06{\times}10^{-4}{\Omega}cm$, while mobility increases from $152cm^2/vs$ to $275cm^2/vs$.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.31 no.2
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• pp.117-121
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• 2018

Perovskite solar cells have received increasing attention in recent years because of their outstanding power conversion efficiency (exceeding 22%). However, they typically contain toxic Pb, which is a limiting factor for industrialization. We focused on preparing Pb-free perovskite films of Ag-Bi-I trivalent compounds. Perovskite thin films with improved optical properties were obtained by applying an anti-solvent (toluene) washing technique during the spin coating of perovskites. In addition, the surface condition of the perovskite film was optimized using a multi-step thermal annealing treatment. Using the optimized process parameters, $AgBi_2I_7$ perovskite films with good absorption and improved planar surface topography (root mean square roughness decreased from 80 to 26 nm) were obtained. This study is expected to open up new possibilities for the development of high performance $AgBi_2I_7$ perovskite solar cells for applications in Pb-free energy conversion devices.