• Textile Coloration and Finishing
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• v.3 no.1
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• pp.8-16
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• 1991

In order to investigate the fine structure of PET films, PET films were stretchd at various draw ratios (2, 3, 4, 5) below $T_g$ ($72^{\circ}C$) and then annealed at various temperatures (125, 150, 175, $200^{\circ}C$) under free-annealed (FA) and taut-annealed (TA) conditions. Such changes as thermal shrinkage, crystallinity, crystallite size, dynamic viscoelasticity and thermal behaviour were measured in relation to the draw ratio and annealing condition.The following results were obtained. 1. Thermal shirinkage increased with increasing annealing temperature and draw ratio, but decreased in case of draw ratio 4 (draw ratio 3 at $200^{\circ}C$) and above it. 2. The degree of crystallinity of FA samples were higher than those of TA samples. 3. Tan 5 of TA samples were less than those of FA samples, and storage moduli (E') and loss moduli (E") of FA samples were less than those of TA samples; moreover, maximum tan '||'&'||' temperature of FA samples were shifted toward higher temperature than those of TA samples. 4. The melting endotherm ($T_m$) and heat of fusion $(\DeltaH)$ of the PET film increased with the draw ratio and annealing temperature; in addition, premelting endotherm ($T_m$) and heat of fusion $(\DeltaH)$ of the local crystallization in the FA samples were larger than those of TA samples. 5. The X-ray diffraction pattern displayed sharp peaks gradually with the draw ratio and annealing temperature. 6. Crystallite sizes of FA samples were larger than those of TA samples.

• Journal of the Korean Ceramic Society
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• v.37 no.11
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• pp.1084-1090
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• 2000

(Bi$_2$O$_2$)$^{2+}$층 사이에 두 개의 Ta-O 팔면체로 연결된 Bi 계의 층상 페로브스카이트 구조인 SrBi$_2$Ta$_2$O$_{9}$ (SBT) 박막을 XPS를 이용하여 깊이별 화학 상태 변화를 분석하였다. 아르곤 이온으로 SBT 박막을 식각하면, SBT 박막의 각 구성물들은 가속 Ar$^{+}$ 이온의 에너지에 따라 변화한다. SBT 각 구성물 중 Sr 3d의 화학 상태는 Ar$^{+}$ 이온의 에너지변화에 따라 근소하게 변화한다. 반면에, Ta 4f와 Bi 4f의 화학 상태 변화는 인가되는 Ar$^{+}$ 이온 에너지에 확실하게 의존한다. 특히, Bi 4f는 Sr과 Ta에 비해 낮은 Ar$^{+}$ 이온 에너지에서도 Bi-O의 화학 상태가 금속 Bi 화학 상태로 현저하게 변화한다. 이러한 SBT 박막의 화학 상태 변화는 산호 원자의 선택적인 식각 때문에 발생하며 선택적인 식각은 SBT 박막 내에서 각 구성물과 산소간의 질량 차이와 각 구성물의 열적 안정성에 의존함을 알 수 있다.

• Applied Science and Convergence Technology
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• v.26 no.4
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• pp.70-73
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• 2017

The dielectric constant and loss of poling/non-poling was measured in the $Pb_{1-3x/2}La_x[(Mg_{1/3}Ta_{2/3})_{0.66}Zr_{0.34}]O_3$ samples. The addition of $La^{3+}$ to the $Pb_{1-3x/2}La_x[(Mg_{1/3}Ta_{2/3})_{0.66}Zr_{0.34}]O_3$ did not cause a large change in grain size. But the addition of $La^{3+}$ did show transition temperature, which shifted toward low temperature in the $Pb[(Mg_{1/3}Ta_{2/3})Zr]O_3$ systems. In addition, the dielectric and pyroelectric properties (${\varepsilon}{\sim}20000$, $p{\sim}0.03C/m^2K$) of this system using $La^{3+}$ have been greatly improved. Pyroelectrics $Pb_{0.97}La_{0.02}(Mg_{1/3}Ta_{2/3})_{0.66}Zr_{0.34}]O_3$ system was found to have a relatively high ferroelectric FOMs ($F_V{\sim}0.035m^2/C$, $F_D{\sim}0.52{\times}10^{-4}Pa^{-1/2}$) at room temperature. Spontaneous polarization showed a value of $0.27{\sim}0.35C/m^2$ in the composition added to $La^{3+}$. The piezoelectric constant ($d_{33}=350{\sim}490pC/N$) and electromechanical coupling factor ($k_P=0.25{\sim}0.35$) are obtained in $Pb_{1-3x/2}La_x[(Mg_{1/3}Ta_{2/3})_{0.66}Zr_{0.34}]O_3$ compositions with $La^{3+}$ dopant.

• Food Science and Preservation
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• v.5 no.4
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• pp.386-391
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• 1998

Lactobacillus plantarum KLAB21 isolated from kimchi has been shown to produce antimutagenic subtance(s) into the culture medium using Salmonella typhimurium TA100 and S. typhimurium TA98 (Rhee and Park, Korean J. Appl. Microbiol.. Biotechnol., 1999, in press). In this study, the effects of culture conditions were investigated to maximize the production of antimutagenic substance(s) against 4-nitro-O-phenylenediamine(NPD) by the strain KLAB21. Glucose(255) as a carbon source and yeast extract or bactopeptone(1%) as a nitrogen source showed the highest production of the antimutagenic substance(s). Optimal initial pH of the culture medium, culture temperature and shaking speed for the antimutagenic substance(s) production were pH 7.0, 37$^{\circ}C$ and 150rpm, respectively. Under the optimal conditions, the antimutagenic activity of L. plantarum KLAB21 culture supernatant against NPD on Salmonella typhimurium TA100 and S. typhimurium TA98 were 73.95% and 59.74%, respectively.

• Journal of Environmental Health Sciences
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• v.20 no.1
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• pp.39-53
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• 1994

This study aims to investigate organic compounds and its toxicity by Ames test and chromosomal aberration in the water of the Nak Dong River. Six sampling sites such as Goryung, Hagueun, Maelie, Duksan, Haedong and Myungiang were selected for these pur15oses. 200 l water samples were absorbed on XAD-2 resin columns (2.5X30cm), eluted with organic solvents mixture of acetone: cyclohexane and then dried under vacuum condition. The extracts from the XAD-2 resin was injected into GC/MS and 184 organic compounds were identified such as aldehydes, aromatic compounds, ketones, phenols, hydrocarbons, alcohols, carboxylic acids, alkanes and some unknowns. The US EPA priority pollutants such as naphthlene, bis(2-ethylhexyl)phthalate and other pollutants, 1,2-diethyl benzene, 1,2,3,4-tetrahydronaphthalene and cyclohexanol were detected in these samples. The concentration of chemical pollutants such as 1,2-diethyl benzene, nephthalene, 1,2,3,4-tetrahydronaphthalene, bis(2-ethylhexyl)phthalate and cyclohexanol were ranged into 1.228 $\mu$g/l, 298 $\mu$g/l, 30.191 $\mu$g/l, 1.147 $\mu$g/l and 2.839 $\mu$g/l, respectively. The mutagenic activity of XAD-2 extracts were tested on Salmonella typhimurium TA 98, TA 100, TA 1535 and TA 1537 and then exhibited strong mutagenic activity against S. typhimurium TA 98 and TA 100 in the presence of S$_9$. Amon them, bis(2-ethylhexyl)phtalate and 1,2-diethyl benzene showed the most strongest mutagenic activity against S. typhimurium TA 98 and TA 100 in the presence of S$_9$. On the other hands, chromosomal aberration of XAD-2 extracts in the human blood cells were not occurred by the sampling water at Goryung, Hagueun, Maelie and Duksan, Chromosomal aberration were also not occurred by the each concentration of 0.05, 0.1 amd 0.3 mg/l of each 1,2-diethyl benzol, bis(2-ethylhexyl)phthalate, naphthalene, phenol, cyclohexanol and benzothiazol test solution.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.08a
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• pp.178-178
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• 2010

With the scaling down of ULSI(Ultra Large Scale Integration) circuit of CMOS(Complementary Metal Oxide Semiconductor)based electronic devices, the electronic devices become more faster and smaller size that are promising field of semiconductor market. However, very narrow line width has some disadvantages. For example, because of narrow line width, deposition of conformal and thin barrier is difficult. Besides, proportion of barrier width is large, thus resistance is high. Conventional PVD(Physical Vapor Deposition) thin films are not able to gain a good quality and conformal layer. Hence, in order to get over these side effects, deposition of thin layer used of ALD(Atomic Layer Deposition) is important factor. Furthermore, it is essential that copper atomic diffusion into dielectric layer such as silicon oxide and hafnium oxide. If copper line is not surrounded by diffusion barrier, it cause the leakage current and devices degradation. There are some possible methods for improving the these secondary effects. In this study, TaNx, is used of Tertiarybutylimido tris (ethylamethlamino) tantalum (TBITEMAT), was deposited on the 24nm sized trench silicon oxide/silicon bi-layer substrate with good step coverage and high quality film using plasma enhanced atomic layer deposition (PEALD). And then copper was deposited on TaNx barrier using same deposition method. The thickness of TaNx was 4~5 nm. TaNx film was deposited the condition of under $300^{\circ}C$ and copper deposition temperature was under $120^{\circ}C$, and feeding time of TaNx and copper were 5 seconds and 5 seconds, relatively. Purge time of TaNx and copper films were 10 seconds and 6 seconds, relatively. XRD, TEM, AFM, I-V measurement(for testing leakage current and stability) were used to analyze this work. With this work, thin barrier layer(4~5nm) with deposited PEALD has good step coverage and good thermal stability. So the barrier properties of PEALD TaNx film are desirable for copper interconnection.

• Journal of Welding and Joining
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• v.23 no.6
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• pp.43-48
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• 2005

This work was carried out to obtain sound welds and to select a most suitable binary metal joint among three different dissimilar binary metal combinations such as Zr-4/Ta, Mo/Ta and Ti/Ta(seal tube/sensor sheath) joints fur the instrumented nuclear fuel irradiation test. To do this, Taguchi experimental method was employed to optimize the experimental data. In addition, metallography, micro-focus x-ray radiography and hardness test were conducted to examine the welds. From the weld bead appearance, penetration depth and bead width as well as weld defects standpoint, Zr-4/Ta joint is suggested for the circumferential joining between a seal tube and a sensor sheath. The optimized welding parameters based on Zr-4/Ta joint are suggested as well.

• JSTS:Journal of Semiconductor Technology and Science
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• v.1 no.4
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• pp.202-208
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• 2001

In Recent results suggested that doping $Ta_2O_5$ with a small amount of $TiO_2$ using standard ceramic processing techniques can increase the dielectric constant of $Ta_2O_5$ significantly. In this paper, this concept is studied using RTCVD (Rapid Thermal Chemical Vapor Deposition). Ti-doped $Ta_2O_5$ films are deposited using $TaC_{12}H_{30}O_5N$, $C_8H_{24}N_4Ti$, and $O_2$ on both Si and $NH_3$-nitrided Si substrates. An $NH_3$-based interface layer at the Si surface is used to prevent interfacial oxidation during the CVD process and post deposition annealing is performed in $H_2/O_2$ ambient to improve film quality and reduce leakage current. A sputtered TiN layer is used as a diffusion barrier between the Al gate electrode and the $TaTi_xO_y$ dielectric. XPS analyses confirm the formation of a ($Ta_2O_5)_{1-x}(TiO_2)_x$ composite oxide. A high quality $TaTi_xO_y$ gate stack with EOT (Equivalent Oxide Thickness) of $7{\AA}$ and leakage current $Jg=O.5A/textrm{cm}^2$ @ Vg=-1.0V has been achieved. We have also succeeded in forming a $TaTi_x/O_y$ composite oxide by rapid thermal oxidation of the as-deposited CVD TaTi films. The electrical properties and Jg-EOT characteristics of these composite oxides are remarkably similar to that of RTCVD $Ta_2O_5, suggesting that the dielectric constant of $Ta_2O_5$ is not affected by the addition of $TiO_2$.

• Korean Journal of Optics and Photonics
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• v.8 no.4
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• pp.283-290
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• 1997

Scattering measurement on high reflection dielectric multilayer mirrors deposited on quartz substrate in a vacuum chamber were performed using a total integrated scattering method. Scattering of (Ta$_2$$O_5$/SiO$_2$) multilayer mirrors deposited at 250-30$0^{\circ}C$ was 0.048-0.050% and did not change with an annealing at 30$0^{\circ}C$ for 4 hours. On the other hand, scattering of (TiO$_2$/SiO$_2$) multilayer mirror at 25$0^{\circ}C$ was 0.029% and it showed the heavy tensile stress after an annealing. The rms roughness of (Ta$_2$$O_5$/SiO$_2$) multilayer mirror was almost the same as that of (TiO$_2$/SiO$_2$)multilayer mirror. The column size of Ta$_2$$O_5$ film was smaller than that of TiO$_2$film and the packing density of (Ta$_2$$O_5$/SiO$_2$) multilayer mirrors was higher than that of (TiO$_2$/SiO$_2$) multilayer mirror. It seems that the higher packing density and smaller column size of Ta$_2$$O_5$ films lead to more scattering.

• Transactions of the Korean hydrogen and new energy society
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• v.28 no.2
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• pp.137-143
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• 2017

In the present study, Ni and $TaF_5$ were chosen as additives to enhance the hydriding and dehydriding rates of Mg. A sample with a composition of 80 wt% Mg + 14 wt% Ni + 6 wt% $TaF_5$ (named $80Mg+14Ni+6TaF_5$) was prepared by high-energy ball milling in hydrogen. Its hydriding and dehydriding properties were then examined. At the fourth cycle, the activated sample absorbed 3.88 wt% H for 2.5 min, 4.74 wt% H for 5 min, and 5.75 wt% H for 60 min at 593 K under 12 bar $H_2$. $80Mg+14Ni+6TaF_5$ had an effective hydrogen-storage capacity (the quantity of hydrogen absorbed for 60 min) of about 5.8 wt%. The sample desorbed 1.42 wt% H for 5 min, 3.42 wt% H for 15 min, and 5.09 wt% H for 60 min at 593 K under 1.0 bar $H_2$. Line scanning results by EDS for $80Mg+14Ni+6TaF_5$ before and after cycling showed that the peaks of Ta and F appeared at different positions, indicating that the $TaF_5$ in $80Mg+14Ni+6TaF_5$ was decomposed.