• 한국재료학회지
• /
• 제9권8호
• /
• pp.837-842
• /
• 1999

Ta/TaN 다층피막구조는 경도는 떨어지지만 연성이 큰 Ta 막과 취성을 가지며 경도가 높은 TaN 막을 교대로 반복하여 만든 다층구조로서 경도와 연성의 장점이 잘 조화되어 높은 인성을 나타낼 것으로 기대된다. 본 연구에서는 고속도강 기판위에 Ta/TaN 복합다층피막과 compositional gradient Ta-TaN 막을 각각 반응성 스퍼터링에 의하여 증착하고 열처리에 따른 경도 및 접착성을 조사하였다. $N_2$/Ar 유량비가 0.4일 때 결정성이 가장 우수한 TaN 막이 얻어지며, Ta/TaN 복합다층피막의 경도 및 스크래치 테스트 결과도 가장 우수하였다. 또한 Ta/TaN 복합다층피막 증착후의 어닐링 처리 시 어닐링 온도가 증가할수록 피막의 경도와 접착성이 악화되었으며, compositional modulation wavelength가 감소함에 따라 Ta/TaN 복합다층피막의 경도는 증가하지만 접착성은 wavelength에 대한 의존성이 약하게 나타났다. 그리고 compositional gradient Ta-TaN 막 증착후의 어닐링 처리 시 경도와 스크래치 테스트 값은 각각 20$0^{\circ}C$와 40$0^{\circ}C$에서 최대값을 나타내었다.

• 한국연초학회지
• /
• 제19권2호
• /
• pp.129-135
• /
• 1997

This study was carried out to investigate the influence of triacetin(TA) on some phisico-chemical properties of cigarette filter rods. To find the effect of TA on physical properties, we made six kinds of filters varying the TA levels(0%, 2%, 4%, 6%, 8%, 10%) and measured the hardness, resilience and roundness. The hardness of filter rods was increased from 83.2% to 94.6% with increasing the TA level hut the roundness was not affected by TA levels. After manufacturing the cigarette with the filters, we have analysed the delivery amount of phenol and TA with the content of TA. The amount of phenol was decreased from 20.6$\mu\textrm{g}$/cig. to 12.0 $\mu\textrm{g}$/cig. with increasing the TA level of the filters. The decreasing of phenol amount was thought to be caused by solution effect. Also the TA delivery of TPM was increased from 0% to 5% of TPM with increasing the amount of TA. We have found the interesting phenomena that ventilation rate was also decreasing up to 6oye with increasing TA. It seemed to be due to the encapsulated pressure drop and the reduction of the plugwrap porosity which also caused by the smear with TA on the surface of plugwrap. From this results, we could find that not only the hardness, resilience and ventilation rate but also the contents of phenol and TA in cigarette smoke was affected by the TA levels on the cigarette filter rods.

• 한국표면공학회:학술대회논문집
• /
• 한국표면공학회 2014년도 추계학술대회 논문집
• /
• pp.256-257
• /
• 2014

The effects of the preparation conditions of ZnO-modified TaON on the photocatalytic activity for degradation of rhodamine B dye (Rh. B) under simulated solar light were investigated. The ZnO/TaON nanocomposite were prepared by loading particulate $Ta_2O_5$ with ZnO using different ZnO contents, followed by thermal nitridation at 1123 K for 5 h under $NH_3$ flow (20 ml min.1). The asprepared samples were characterized by XRD, UV-Vis-DRS, and SEM-EDX. The results revealed that the band gap energy absorption edge of as prepared nanocomposite samples was shifted to a longer wavelength as compared to ZnO and $Ta_2O_5$, and the 60 wt% ZnO/TaON nanocomposite exhibited the highest percentage (99.2 %) of degradation of Rh. B and the highest reaction rate constant ($0.0137min^{-1}$) in 4 h which could be attributed to the enhanced absorption of the ZnO/TaON nanocomposite photocatalyst. Hence, these results suggest that the ZnO/TaON nanocomposite exhibits enhanced photocatalytic activity for the degradation of rhodamine B under simulated solar light irradiation in comparison to the commercial ZnO, $Ta_2O_5$, and TaON.

• 한국결정성장학회지
• /
• 제18권4호
• /
• pp.165-168
• /
• 2008

동시스퍼터법을 이용하여 Ta이 도핑된 $TiO_2$ 박막을 석영 및 ITO 기판위에 제작하였다. Ta의 도핑량은 동시스퍼터법에 의하여 조절되는 Ta 금속선 길이에 의하여 제어 되었다. Ta이 도핑된 $TiO_2$ 박막은 rutile상에서 anatase상으로 구조변화를 유발 시키며 고용체를 형성했다. Ta의 도핑량이 증가함에 따라 rutile상 보다는 anatase상이 많은 것으로 나타났다. XPS 분석에 따르면 도핑된 Ta은 금속이 아닌 $Ta_2O_5$의 산화물을 형성하는 것으로 나타났다. Ta이 도핑된 $TiO_2$ 전극에서는 자외선(UV) 영역을 포함하여 가시광(VIS) 영역의 빛의 조사에 광전류응답 특성을 발현하였다. 가시광선 영역에서 발현된 광전류 응답 특성은 Ta 도핑에 의하여 $TiO_2$ 밴드갭내에 불순물 준위의 형성에 기인한 것으로 사료된다.

• 한국자기학회지
• /
• 제3권1호
• /
• pp.41-47
• /
• 1993

Co-Cr계 수직자기기록매체에서 비교적 낮은 기판온도에서 높은 보자력을 얻기위하여 제 3원소로서 Ta의 첨가효과에 대하여 연구하였다. Cr함량이 17-21 at.%로 다른 Co-Cr 계에 Ta함량을 3.2 at.%까지 첨가시켜서 여러조성의 Co-Cr-Ta 박막을 제조하고, 자기적 성질 및 미세구조를 조사하였다. Ta첨가로 인한 수직보자력의 향상효과는 Cr함량이 낮은 박막의 경우에 컸으며, 특히 기판온도가 $100^{\circ}C$인 경우 그 향상효과가 더욱 뚜렷하였다. Ta의 첨가로 인한 수직보자력 향상은 결정립 미세화나, c-축 배향성향상에 의한 것이기 보다는 비강자성원소의 편석이 심화됨에 기인하는 것으로 판단된다.

• 한국자기학회지
• /
• 제10권6호
• /
• pp.310-317
• /
• 2000

먼지 입자에 의한 thermal asperity(TA)써 발생은 드라이브의 신뢰성에 큰 영향을 미친다. 본 논문에서는 드라이브의 입자 분사 시험 등을 통하여 헤드 및 디스크의 TA민감도를 분석하고 TA발생의 중요 인자들을 고찰하였다. 헤드의 TA 민감도는 MR 및 GMR 센서의 재질 및 특성에 많은 영향을 받으며 특히 바이어스 전류가 증가함에 띠라 TA 민감도는 증가한다. 한편 슬라이더의 ABS 형태를 적절히 설계 함으로서 TA를 어느 정도 감소시킬 수 있다. 디스크의 경우 디스크 카본 overcoat층의 scratch저항력을 증가시킴으로써 TA의 발생을 감소시킬 수 있다. 그러나 먼지 입자가 디스크 표면에 부착되는 정도를 결정하는 표면에너지는 TA 발생에 거의 영향을 미치지 않는다. 이는 TA 발생을 초래하는 먼지 입자의 크기가 1-2 $\mu\textrm{m}$로서 디스크 표면의 윤활막에 의한 모세관력이 너무 커서 입자들이 디스크표면으로부터 이탈할 수 없기 때문이다

• 한국표면공학회지
• /
• 제38권2호
• /
• pp.65-68
• /
• 2005

The effect of crystal orientation and microstructure on the mechanical properties of $TaN_x$ was investigated. $TaN_x$ films were grown on $SiO_2$ substrates by ultrahigh vacuum unbalanced magnetron sputter deposition in mixed $Ar/N_2$ discharges at 20 mTorr (2.67 Pa) and at $350^{\circ}C$. Unlike the Ti-N system, in which TiN is the terminal phase, a large number of N-rich phases in the Ta-N system could lead to layers which had nano-sized lamella structure of coherent cubic and hexagonal phases, with a correct choice of nitrogen fraction in the sputtering mixture and ion irradiation energy during growth. The preferred orientations and the micro-structure of $TaN_x$ layers were controlled by varing incident ion energy $E_i\;(=30eV\~50eV)$ and nitrogen fractions $f_{N2}\;(=0.1\~0.15)$. $TaN_x$ layers were grown on (0002)-Ti underlayer as a crystallographic template in order to relieve the stress on the films. The structure of the $TaN_x$ film transformed from Bl-NaCl $\delta-TaN_x$ to lamellar structured Bl-NaCl $\delta-TaN_x$ + hexagonal $\varepsilon-TaN_x$ or Bl-NaCl $\delta-TaN_x$ + hexagonal $\gamma-TaN_x$ with increasing the ion energy at the same nitrogen fraction $f_{N2}$. The hardness of the films also increased by the structural change. At the nitrogen fraction of $0.1\~0.125$, the structure of the $TaN_x$ films was changed from $\delta-TaN_x\;+\;\varepsilon-TaN_x\;to\;\delta-TaN_x\;+\;\gamma-TaN_x$ with increasing the ion energy. However, at the nitrogen fraction of 0.15 the film structure did not change from $\delta-TaN_x\;+\;\varepsilon-TaN_x$ over the whole range of the applied ion energy. The hardness increased significantly from 21.1 GPa to 45.5 GPa with increasing the ion energy.

• Corrosion Science and Technology
• /
• 제22권5호
• /
• pp.368-376
• /
• 2023

Dental Ni-Ti files must ensure stability and resistance to fatigue fracture. DLC and ta-C were coated to remove defects on the surface and ensure stability, and the surface characteristics were investigated. When coated with DLC, it was black, and in case of ta-C coating, it was blue-black. Scratches, which are defects caused by mechanical processing, were formed on the surface of the un-coated Ni-Ti file from the end of the file along the direction of processing, with the Pro-file appearing in the vertical direction and the K-file appearing in the file direction. Scratches were reduced on the coated surface, and the surface roughness was greatly reduced after coating compared to before coating. The un-coated Ni-Ti file had the lowest hardness, the DLC-coated file had the highest hardness, and ta-C showed relatively high hardness. The elastic modulus of the DLC coating film was high, and the ta-C elastic modulus was low. The adhesion of the DLC coating film tended to be higher than that of ta-C, and the wear loss amount of DLC coating of taC was lower. The corrosion potential of the ta-C coating increased significantly, and the corrosion current density decreased.

• 한국식품위생안전성학회지
• /
• 제15권4호
• /
• pp.297-303
• /
• 2000

우리나라 전통 장류인 간장, 된장, 고추장, 청국장의 위생화를 위한 방사선 조사기술의 이용 가능성을 검토할 목적으로 방사선 조사를 실시한 후 유전독성학적 안전성 실험의 일환으로 Ames test를 실시하였다. 감마선 조사 및 비조사된 간장, 된장, 고추장, 청국장 물추출 분획의 Salmonella typhimurium TA98, TA100, TA1535 및 TA1537에 대한 복귀변이 집락수를 조사한 결과, 대사활성계 도입 및 부재시 모두, 모든 시험균주에서 시험적용 농도인 10,000 $\mu\textrm{g}$/plate까지의 농도에서 복귀변이 집락수의 농도 의존적인 증가 혹은 감소를 보이지 않아 20 kGy의 고선량 감마선 조사된 간장, 된장, 고추장, 청국장은 돌연변이원성이 없는 것을 확인할 수 있었다.

• 대한간호학회지
• /
• 제27권3호
• /
• pp.520-530
• /
• 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.