• Journal of Technologic Dentistry
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• v.26 no.1
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• pp.97-104
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• 2004

A new Ti-10Ta-10Nb alloy has designed and examined some possibility of forming more passive oxide film by oxidation treatment which is closely related to corrosion resistance and biocompatibility. Ti-6Al-4V and Ti-10Ta-10Nb alloys were prepared by consumable vacuum arc melting and homogenized at 1050$^{\circ}C$ for 24hours. Alloy specimens were oxidized at the temperature range of 400 to 750$^{\circ}C$ for 30minutes, and the oxide films on Ti alloys were analysed by optical microscope, SEM, XPS and TGA. Cytotoxicity test was performed in MTT assay treated L929 fibroblast cell culture by indirect method. It is found out that the oxide film on Ti-10Ta-10Nb alloy is denser and thinner compared to Ti-6Al-4V alloy. The weight gain during the oxidation was increased rapidly at the temperature above 650$^{\circ}C$ for Ti-6Al-4V alloy and above 700$^{\circ}C$ for Ti-10Ta-10Nb alloy respectively. It was analysed that the passive film of the Ti alloys consisted of TiO2 through X-ray photoelectron spectroscopy (XPS) analysis. It is found out by cytotoxicity test that moderate oxidation treatment lowers cell toxicity, and Ti-10Ta-10Nb alloy showed better result compared to Ti-6Al-4V alloy.

• Food Science and Preservation
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• v.11 no.2
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• pp.221-226
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• 2004

This study was carried out to determine the antimutagenic and anticancer effects of Allium victoriolis using Ames test and cytotoxicity. Allium victorialis extracted with ethanol and then further fractionated to chloroform, ethyl acetate and water. The inhibition rate of ethanol extract (200 $\mu\textrm{g}$/plate) of Allium victorialis in the Salmonella typhimurium TA100 strain showed 88.2% against the mutagenesis induced by N-methyl-N'-nitro-N-nitrosoguanidine(MNNG). The suppression ratio against 4-nitroquinoline-1-oxide(4NQO) in the Salmonella typhimurium TA98 and TA100 strains showed 76.4% and 83.0%, respectively. The cytotoxicity effects of Allium victorialis extract against the cell lines with human lung carcinoma (A549), human breast adenocarcinoma (MCF-7) and human gastric cacinoma (KATOIII) were inhibited with the increase of extract concentration. The treatment of 0.5 $\mu\textrm{g}$/plate Allium victorialis of ethanol extract showed strong cytotoxicities of 74.2%, 71.3% and 67.4% against A549, MCF-7 and KATOIII, respectively.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.619-619
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• 2013

The interfacial state between $Ta_2O_5$ and a Si substrate during the growth of $Ta_2O_5$ films by atomic layer deposition (ALD) was investigated using in-situ synchrotron radiation photoemission spectroscopy (SRPES). A newly synthesized liquid precursor Ta($N^tBu$) $(dmamp)_2Me$ was used as the metal precursor, with Ar as a purging gas and $H_2O$ as the oxidant source. After each half reaction cycle, samples were analyzed using in-situ SRPES under ultrahigh vacuum at room temperature. SRPES analysis revealed that Ta suboxide and Si dioxide were formed at the initial stages of $Ta_2O_5$ growth. However, the Ta suboxide states almostdisappeared as the ALD cycles progressed. Consequently, the $Ta^{5+}$ state, which corresponds with the stoichiometric $Ta_2O_5$, only appeared after 4.0 cycles. Additionally, tantalum silicate was not detected at the interfacial states between $Ta_2O_5$ and Si. The measured valence band offset between $Ta_2O_5$ and the Si substrate was 3.22 eV after 3.0 cycles.

• Korean journal of food and cookery science
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• v.11 no.1
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• pp.77-82
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• 1995

Croaker and pork were cooked by four kinds of methods(boiled, broiled, deep fried, pan fried) and their extracts were extracted with 50% methanol. The Ames test were performed on these methanol extracts, employing Salmonella typhimurium tester strain TA98 and TA100, with and without S9 mix and after nitrite treatment. The methanol extracts of cooked croaker and pork showed mutagenicity between original weight 0.0125 g/plate and 0.1 g/plate in all strains and induced a higher mutagenicity in all strains with S9 mix than without S9 mix. In all kinds of cooking methods, pork extracts showed higher mutagenicities than croaker extracts and especially the extract of pan fried croaker and pork showed high mutagenicities with S9 mix. The extract after nitrite treatment showed higher mutagenicities than that after non treatment and after treatment with nitrite, the mutagenicities of extracts were higher on TA98 than TA100.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.334-334
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• 2012

Transparent oxide semiconductors have recently attracted much attention as channel layer materials due to advantageous electrical and optical characteristics such as high mobility, high stability, and good transparency. In addition, transparent oxide semiconductor can be fabricated at low temperature with a low production cost and it permits highly uniform devices such as large area displays. A variety of thin film transistors (TFTs) have been studied including ZnO, InZnO, and InGaZnO as the channel layer. Recently, there are many studies for substitution of Ga in InGaZnO TFTs due to their problem, such as stability of devices. In this work, new quaternary compound materials, tantalum-indium-tin oxide (TaInSnO) thin films were fabricated by using co-sputtering and used for the active channel layer in thin film transistors (TFTs). We deposited TaInSnO films in a mixed gas (O2+Ar) atmosphere by co-sputtering from Ta and ITO targets, respectively. The electric characteristics of TaInSnO TFTs and thin films were investigated according to the RF power applied to the $Ta_2O_5$ target. The addition of Ta elements could suppress the formation of oxygen vacancies because of the stronger oxidation tendency of Ta relative to that of In or Sn. Therefore the free carrier density decreased with increasing RF power of $Ta_2O_5$ in TaInSnO thin film. The optimized characteristics of TaInSnO TFT showed an on/off current ratio of $1.4{\times}108$, a threshold voltage of 2.91 V, a field-effect mobility of 2.37 cm2/Vs, and a subthreshold swing of 0.48 V/dec.

• Korean Journal of Materials Research
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• v.1 no.1
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• pp.17-22
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• 1991

Tantalum thin films were deposited by DC sputtering on heavily doped single Si substrates. These substrates were treated by means of a rapid thermal annealing (RTA) under Ar atmosphere for various temperatures($600-1100^{\circ}C$). The silicide formation and the impurities behavior in the substrate are studied by means of XRD, SEM, four-point probe, HP4145, and SIMS. The formation of $TaSi_2$ started at $800^{\circ}C$ for all kinds of impurities and the entire Tantalum thin metal films were transformed into $TaSi_2$ above $1000^{\circ}C$ Also the contact resistance for $TaSi_2/P^+$ region had a low value; $22{\Omega}$, at contact site of $0.9{\times}0.9(\mu\textrm{m^2}$), and implanted impurities were diffused out into the $TaSi_2$ for rapid thermal annealing.

• Journal of dental hygiene science
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• v.6 no.4
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• pp.295-302
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• 2006

This study was conducted to study the effects of the TA Theory and the TA Program, an educational testing tool developed to improve functional communication skills for dental hygienists. The results taken from the experiment using the TA program has been verified by Examination Tool for Personnel Communication developed by Chung(2001). 44 in two experimental groups and 16 in control group took part in TA Program training sessions. The experimental Group I received TA technique training session for 12 hours per day in a period of three days and Group II for 6 hours per day in a period of two days. From this experiment, the following conclusion was obtained. The results are as follows: 1) As it can be seen from the results of the examination taken prior to the experiment, the subjects of the control group and experimental groups were homogenous in all categories including self-disclosure, awareness, evaluation and acceptance of feedback, self-expression, coping with feelings, clearness, avoidance, dominance, handling of differences, and perceived acceptance. 2) After the training of TA Program was completed on Group I and II, the examination results are as follows: Control Group (1.5158), Group I (1.8260) / Control Group (1.4684), Group II (1.9985). The results of Group I and II (1.7970 and 1.9985 respectively) therefore showed a meaningful difference. 3) From the results of the experiment it is shown that dental hygienists' communication skills improved after receiving the TA Program training. Therefore TA Program may be used as an effective tool for such purpose. 4) As it can be observed from the data, Group I and II showed difference in the degree of improvements. Therefore, there needs to be a further investigation on the effects of the difference in training period. 5) This program is not only limited to the education of dental hygienists but may be widely applied to various forms of education and teaching methods.

• Transactions of the Korean hydrogen and new energy society
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• v.7 no.1
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• pp.81-92
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• 1996

The Ar/Ar-$H_2$ plasma method was applied to reduce oxides and refine metals of V, Ta and B. In addition, the high temperature chemical reaction in Ar plasma and of the refining reaction in the Ar-(20%)$H_2$ plasma were analyzed. The crude V of 96wt% purity was obtained at the ratio of $C/V_{2}O_{5}=4.50$ by the Ar plasma reduction grade and the maximum reduction was obtained at $C/V_{2}O_{5}=4.50$ due to the $O_{2}$ loss from the thermal decomposition of vanadium oxide. In the Ar-(20%)$H_2$ plasma refining, the metallic V of 99.2wt% was produced at the ratio of $C/V_{2}O_{5}=4.40$. It was considered that a main refining reaction resulted from the chemical reaction between the residual carbon and residual oxygen. The metallic Ta of 99.8wt% was obtained at the ratio of $C/Ta_{2}O_{5}=5.10$ in a Ar plasma reduction and the Oz loss from the thermal decomposition of tantalum pentoxide did not take place. The deoxidation reaction was more significant than the decarburization reaction in the Ar-(20%)$H_2$ plasma refining and the metallic Ta of 99.9wt% was produced within the range of $C/Ta_{2}O_{5}$ ratio of 4.50 to 5.10. The Vickers hardness of Ta in the above mentioned range was about 220Hv due to the decrease in a residual oxygen by the deoxidation reaction. On the other hand, C is no suitable agent for the reduction of $B_{2}O_{3}$ by the Ar and Ar-$H_2$ plasma. But Fe-B-Si alloy was produced with the reduction of $B_{2}O_{3}$ in the melt when Fe, C, $B_{2}O_{3}$, and ferroboron mixtures were melted by the high frequency induction melting.

• ETRI Journal
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• v.14 no.4
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• pp.43-55
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• 1992

본 고는 광대역 ISDN 의 전송방식인 ATM(Asynchronous Transfer Mode) 프로토콜의 설계 및 구현에 대하여 기술하였으며, 설계된 ATM 프로토콜은 그 기능을 검증하기 위하여, 광대역 ISDN 을 통하여 Ethernet LAN간 연결을 지원하는 LAN TA(Terminal Adaptor), DS3 급 CBR(Constant Bit Rate) 비디오 서비스를 위한 비디오 TA에 적용하였다. LAN TA 와 비디오 TA에 적용되는 ATM 프로토콜은 공통으로 사용할 수 있도록 모듈화하여 설계하였으며 물리계층의 전송 매체 부분은 최대 100Mbit/s 까지 전송속도를 수용할 수 있도록 고려하였다.

• Korean Journal of Food Science and Technology
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• v.32 no.6
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• pp.1371-1378
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• 2000

This study was performed to determine the antimutagenic and cytotoxic effect of Agaricus blazei Murill methanol extract on Salmonella typhimurium TA98, TA100 and human cancer cell lines using Ames test and cytotoxicity assay, respectively. In Ames test, methanol extract from A. blazei Murill did not exhibit any mutagenicity and most of the samples showed high antimutagenic effects against mutation induced by N-methyl-N'-nitro-N-nitrosoguanidine(MNNG), 4-nitroquinoline-1-oxide(4NQO), 3-amino-1,4-dimethyl-5H-pyrido [4,3-b] indol(Trp-P-1) and $benzo({\alpha})pyrene(B({\alpha})P)$. The methanol extracts of A. blazei Murill$(200\;{\mu}g/plate)$ showed approximately 92.4%, 81.9% and 83.4% inhibitory effect on the mutagenesis induced by 4NQO, Trp-P-1 and $B({\alpha})P$ against TA98 strain, whereas 87.3%, 94.7%. 92.3% and 89.9% inhibitions were observed on the mutagenesis induced by MNNG, 4NQO, Trp-P-1 and $B({\alpha})P$ against TA100 strain. The solvent fractions of methanol extracts from A. blazei Murill except water fraction showed high antimutagenic effects of $70{\sim}90%$ against mutation induced by MNNG, 4NQO. Trp-P-1 and $B({\alpha})P$. In anticancer effects of A. blazei Murill extract and fraction against cancer cell lines including human breast adenocarcinoma(MCF7), human lung carcinoma(A549), human fibrosarcoma(HT1080), human hepatocellular carcinoma(Hep3B), human epitheloid carcinoma(HeLa), human gastric carcinoma(KATO III) and human chronic myelogenous leukemia(K562) were investigated. The treatment of 1 mg/mL A. blazei Murill extracts had the highest cytotoxicity with 91.9% against HeLa, followed by KATO III(88.7%), A549(86.5%) and Hpe3B(84.3%). Whereas 1 mg/mL treatment of A. blazei Murill extracts had only $10{\sim}40%$ cytotoxicity on human normal liver cell (WRL68).