• Transactions on Electrical and Electronic Materials
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• v.18 no.2
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• pp.74-77
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• 2017

In this work, we investigated the etching characteristics of TaNO thin films and the selectivity of TaNO to $SiO_2$ in an $O_2$/CF4/Ar inductively coupled plasma (ICP) system. The maximum etch rate of TaNO thin film was 297.1 nm/min at a gas mixing ratio of O2/CF4/Ar (6:16:4 sccm). At the same time, the etch rate was measured as a function of the etching parameters, such as the RF power, DC-bias voltage, and process pressure. X-ray photoelectron spectroscopy analysis showed the efficient destruction of the oxide bonds by the ion bombardment, as well as the accumulation of low volatile reaction products on the etched surface. Based on these data, the ion-assisted chemical reaction was proposed as the main etch mechanism for the $CF_4$-containing plasmas.

• Journal of the Korean Magnetics Society
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• v.3 no.1
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• pp.41-47
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• 1993

Effects of Ta addition on Co-Cr pependicular magnetic recording media were studied to obtain high perpen-dicular coercivity at lower substrate temperature. For the purpose. magnetic properties and microstructures of Co-Cr-(Ta) films were studied by varying the Cr contents from 17 to 21 at.% and Ta contents for 0 to 3.2 at.%. Effectiveness of Ta addition in increasing perpendicular coercivity was significant for lower Cr content films. The increasement of perpendicular coercivity was more pronounced for the films deposited on $100^{\circ}C$ heated substrate in the case of ${(Co_{83}Cr_{17})}_{98.4}Ta_{1.6}$ composition. The cause of the increase of perpendicular coercivity was considered due to not the grain refinement effects and the improvement of c-axis alignments but increase of Ta and Cr segregation.

• Journal of the Mineralogical Society of Korea
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• v.26 no.4
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• pp.245-262
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• 2013

We analyzed 29 surface sediment samples in five submarine volcanoes (TA12, TA19, TA22, TA25, and TA26) located in the southern part of the Tonga arc for trace elements and rare earth elements to investigate characteristics of the hydrothermal alteration of surface sediments. Based on analytical results of trace element and rare earth element (REE), surface sediments of TA12, TA19, and TA22 submarine volcanoes, which are located in the northern part of the study area, were very little or not influenced by hydrothermal fluids. In contrast, some stations of TA25 and TA26 submarine volcanoes were strongly affected by hydrothermal fluids. However, these two submarine volcanoes showed different features in element concentration in the sediments. Some stations of TA25 submarine volcano showed enrichment of Ni, Cu, Sn, Zn, Pb, Cr, Cd, Sb, W, Ba, Ta, Rb, Sr, and As, however, those of TA26 submarine volcano showed enrichment of Sn, Zn, Pb, Cd, Sb, Ba, Rb, and Sr. Stations which enriched trace elements were observed, enriched REEs were also observed. Average upper continental crust (UCC)-normalized REE patterns of the surface sediments generally showed low light REE (LREE) abundances and increased heavy REE (HREE) abundances. Eu enrichment was identified at several stations of TA25 and TA26 submarine volcanoes. In addition, enrichment of Ce was found at some stations of TA26 submarine volcano and these enrichment patterns were similar with hydrothermal fluid of near stations. Furthermore, TA25 and TA26 submarine volcanoes showed different enrichment characteristics of trace elements and REE. Trace elements were concentrated at TA25 submarine volcano. TA26 submarine volcano, on the other hand, observed highly enrichment of REE especially, Eu and Ce. As a result of the investigation, the characteristics and concentrations of REEs and trace elements in the surface sediments of each submarine volcano can be applied to identify hydrothermal alteration of sediments during exploration for hydrothermal deposits.

• Journal of Korean Medicine Rehabilitation
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• v.19 no.2
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• pp.227-239
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• 2009

Objectives : The purpose of this study is to investigate the relation of Ferguson's angle, Lumbar lordotic angle, Lumbar IVD angle in traffic accident patients. Methods : Total patients were classified into TA(traffic accident) inpatients and non-TA(lumbago) inpatients. We analyzed the characteristics of each group Ferguson's angle, Lumbar lordotic angle, L4-5 IVD angle, L5-S1 IVD angle on X-ray film. Results : 1. Ferguson's angle and Lumbar lordotic angle were smaller than normal range. Non-TA group's angles were smaller than TA group's angles. 2. L4-5 IVD angle of female showed smaller than that of male in TA groups. The older age was, the smaller L4-5 IVD angle was at non-TA groups. 3. L5-S1 IVD angle of female showed smaller than that of male in total groups. The older age was, the smaller L5-S1 IVD angle was at non-TA groups. 4. Ferguson's angle, Lumbar lordotic angle, Lumbar IVD angle were related with direct proportion in total groups. 5. Non-TA groups showed more effective VAS variation than TA groups. Conclusions : Lumbar angles were intimately related with each others. And lumbar angles have an effect on curative value.

• Journal of Periodontal and Implant Science
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• v.38 no.4
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• pp.595-602
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• 2008

Purpose: Ti-6Al-4V alloy is widely used as an implant material because of its good biocompatibility and good mechanical property compared with commercial pure titanium. Otherwise, toxicity of aluminum and vanadium in vivo has been reported. Ti-8Ta-3Nb alloy is recently developed in the R&D Center for Ti and Special Alloys and it was reported that this alloy has high mechanical strength, no cytotoxicity and similar biocompatibility to commercial pure titanium, but many studies are needed for its clinical use. In these experiment, we carried out different surface treatment on each Ti-8Ta-3Nb alloy disks, then cultured cell on it and assessed biological response. Materials and Methods: cpTi, Ti-6Al-4V, Ti-8Ta-3Nb alloy disks were prepared and carried out sandblasting and acid etching (SLA) or alkali-heat treatment (AH) on the Ti-8Ta-3Nb alloy disks. We cultured primary rat calvarial cells on each surface and assessed early cell attachment and proliferation by scanning electron microscopy, cell proliferation, alkaline phosphatase activity. Result: The rates of cell proliferation on the cpTi, Ti-8Ta-3Nb AH disks were higher than others (p<0.05) and alkaline phosphatase activity was significantly enhanced on the Ti-STa-8Nb AH disks(p<0.05). Conclusion: Most favorable cell response was shown on the Ti-8Ta-3Nb AH surfaces. It is supposed that alkali-heat treatment of the Ti-8Ta-3Nb alloy could be induced earlier bone healing and osseointegration than smooth surface.

• Journal of the Korean Vacuum Society
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• v.9 no.4
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• pp.360-366
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• 2000

$Sr_xBi_{2.4}Ta_2O_9$ (SBT) thin films of 150 nm thickness were prepared using LSMCD (Liquid Source Misted Chemical Deposition) process with variation of the Sr/Ta mole ratio of 0.35~0.65, and their crystalline phase, microstructure, ferroelectric properties and leakage current characteristics were investigated. Ferroelectric characteristics of the LSMCD-derived SBT films were optimized at the Sr/Ta moleratio of 0.425. The remanent polarization (2Pr) and coercive field (Ec) of the SBT film with the Sr/Ta mole ratio of 0.425 were measured as 15.01 $\mu$C/$ \textrm{cm}^2$ and 41 kV/cm at an applied voltage of $\pm$5 V respectively. LSMCD-derived SBT films with the Sr/Ta mole ratio of 0.35~0.5 exhibited leakage current densities lower than $10^{-5} A/\textrm{cm}^2$ at an applied field of 100 kV/cm, and excellent fatigue-free characteristics of the remanent polarization decrement less than 1% after $10^{10}$ switching cycles at$\pm$5 V.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.08a
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• pp.283.2-283.2
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• 2013

The variation of chemical and interfacial state during the growth of Ta2O5 films on the Si substrate by atomic layer deposition (ALD) was investigated using in-situ synchrotron radiation photoemission spectroscopy. A newly synthesized liquid precursor Ta(NtBu)(dmamp)2Me was used as the metal precursor, with Ar as a purging gas and H2O as the oxidant source. The core-level spectra of Si 2p, Ta 4f, and O 1s revealed that Ta suboxide and Si dioxide were formed at the initial stages of Ta2O5 growth. However, the Ta suboxide states almost disappeared as the ALD cycles progressed. Consequently, the Ta5+ state, which corresponds with the stoichiometric Ta2O5, only appeared after 4.0 cycles. Additionally, tantalum silicate was not detected at the interfacial states between Ta2O5 and Si. The measured valence band offset value between Ta2O5 and the Si substrate was 3.08 eV after 2.5 cycles.

• Journal of Food Hygiene and Safety
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• v.15 no.4
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• pp.297-303
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• 2000

Gamma irradiation at 20 kGy was applied to Kanjang (soy sauce), Doenjang (soybean paste), Kochujang (hot pepper pasts) and Chungkukjang for their possible genotoxicity. The genotoxicity of 20 kGy-irradiated samples was evaluated by Salmonella typhimurium reversion assay. The Salmonella tester strains included TA98, TA100, TA1535 and TA1537 in the absence and presence of an exogenous metabolizing system (59 mix). All samples were negative in the bacterial reversion assay with S. typhimurium TA98, TA100, TA1535 and TA1537. The results indicated that 20 kGy of gamma irradiation on water-soluble fraction of Kanjang, Doenjang, Kochujang and Chungkukjang were not shown mutagenicity.

• Journal of Korean Academy of Nursing
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• v.27 no.3
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• pp.520-530
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• 1997

Antineoplastic agents may exhibit effects not only in patients therapeutically exposed, but also in health workers who prepare and administer these drugs. This study was done to clarify whether nurses who handle anticancer drugs show signs of drug absorption. The experimental group was 14 nurses handling anticancer drugs at three medical wards of a hospital in J city ; the control group was 12 psychiatric nurses at the same hospital. The test materials were the nurses' 24hr urine specimens, which were concentrated by XAD-2 column chromatograpy. Tester strains were TA98(±S9mix), TA100(±S9 mix), TA1535(±S9 mix) and TA1537(±S9 mix) : the salmonella mammalian microsomal test (Ames test) was used for the urinary mutagenicity assay. The results are summarized as follow : 1. In qualitative analysis of the results, both experimental group and control group showed 15.4% urine toxicity. 2. The experimental group revealed significantly higher urinary mutagenicity both in the activation method test and non-activation method test of the tester strains TA98, TA100 and TA1535. In the case of TA1537, the two groups showed no difference in the non-activation method test, but the activation method revealed a difference. 3. In urinary mutagenicity of the experimental group by ward career, there was a significant difference between the group with more than 20 months experience and the group with less than 20 months on the tester strains TA98, TA100, and TA1537. No Significant difference was found between two groups by the tester strain TA1535.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.04b
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• pp.9-12
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• 2004

This paper investigated the stability of Ta-Mo alloy on thin gate dielectric. Ta-Mo alloy was deposited by using co-sputtering process after thermal growing of 3.4nm and 4.2nm silicon dioxide. When the sputtering power of Ta and Mo were 100W and 70W, respectively, the suitable work function for NMOS gate electrode, 4.2eV, could obtain. To prove interface thermal stability of thin film gate dielectric and Ta-Mo alloy, rapid thermal annealing was performed at $600^{\circ}C$ and $700^{\circ}C$ for 10sec in Ar ambient. The results of interface reaction were surveyed by change of silicon dioxide thickness and work function after annealing process. Also, the reliability of alloy gate and gate dielectric could be confirmed by quantity of leakage current. Ta-Mo alloy was showed low sheet resistance and thermal stability, namely, little change of gate dielectric and work function, after $700^{\circ}C$ annealing process.