Browsing by Author "Liu, TF"

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Aggregation of zinc protoporphyrin in anodized aluminum oxide (AAO) nanoporous environments
(2006-02-01)
Lin, JS
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Chen, YC
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Chen, CC
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Diau, EWG
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Liu, TF
The aggregation behavior of zinc protoporphyrin (ZnPP) inside nanoporous environments of anodized aluminum oxide (AAO) has been investigated through observation of the variation of UV/visible absorption and emission spectra of the system. The Soret band in the absorption spectrum of ZnPP/AAO thin-film samples becomes much broader than that observed for ZnPP/THF solutions, and the relative intensity of the Q band is distinctly enhanced for the former. The broad Soret band overlaps the enhanced Q band increasingly as the degree of aggregation increases with increasing duration of immersion, with initial concentration of ZnPP/THF solutions, or with decreasing pore size of AAO nanotubes. A strong excitonic coupling between the Soret and Q transition dipoles causes the absorption spectrum of the ZnPP/AAO system to cover the entire visible spectral region. Emission spectra of ZnPP/AAO samples in the steady state contain multiple resolvable components assigned to monomer, dimer and higher aggregates. The observed systematic variation of emission spectra of ZnPP/AAO samples is consistent with the observation in absorption spectra of the system and reflects the significance of aggregation of ZnPP in a specific nanoporous environment.
As-quenched microstructure of a Cu-14.6Al-4.3Ni alloy
(2001-04-02)
Tan, J
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Liu, TF
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材料科學與工程學系
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Department of Materials Science and Engineering
In the as-quenched condition, the microstructure of the Cu-14.6Al-4.3Ni alloy is DO3 phase containing extremely fine precipitates. Transmission electron microscopy examinations indicated that the extremely fine precipitates are L-J phase, rather than 2H phase. In addition, electron diffraction analyses indicated that the L-J precipitate has two variants with the DO3 matrix. These results are quite different from those reported by other workers in a Cu-14.2Al-4.3Ni alloy. (C) 2001 Elsevier Science B.V. All rights reserved.
As-quenched microstructure of a Cu-24.8Mn-30.0Al alloy
(1996-01-01)
Chu, KC
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Jeng, SC
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Liu, TF
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交大名義發表
;
材料科學與工程學系
As-quenched microstructures of Cu-14.2Al-xNi alloys
(2000-11-27)
Tan, J
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Liu, TF
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材料科學與工程學系
;
Department of Materials Science and Engineering
As-quenched microstructures of Cu3-XMnxAl alloys
(2006-08-01)
Yang, SY
;
Liu, TF
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材料科學與工程學系
;
Department of Materials Science and Engineering
In the as-quenched condition, the microstructure of the Cu2.9Mn0.1 Al alloy was of DO3 phase containing gamma(')(1) martensite. This is similar to that reported by other workers in the Cu3Al alloy. However, the as-quenched microstructure of the Cu2.8Mn0.2Al or Cu2.7Mn0.3Al alloy were found to be of DO3 phase containing extremely fine L-J precipitates, whereas for Cu2.6Mn0.4Al alloy, it was a mixture of (DO3 + L2(1) + L-J) phases. These results are different from those proposed by Bouchard et al. (c) 2005 Elsevier B.V. All rights reserved.
Grain boundary precipitation behaviors in an Fe-9.8Al-28.6Mn-0.8Si-1.0C alloy
(1996-01-01)
Chao, CY
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Hwang, CN
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Liu, TF
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交大名義發表
;
材料科學與工程學系
Grain boundary precipitation reactions in a wrought Fe-8Al-5Ni-2C alloy prepared by the conventional ingot process
(1998-02-01)
Hwang, CN
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Liu, TF
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材料科學與工程學系
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Department of Materials Science and Engineering
Orientation relationship between beta-Mn and L2(1) matrix in a Cu2MnAl alloy
(1999-07-01)
Chu, KC
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Liu, TF
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材料科學與工程學系
;
Department of Materials Science and Engineering
In the as-quenched condition, the microstructure of the Cu2MnAl alloy was L2(1) phase containing extremely fine L-J precipitates. This result is different from that reported by other workers in the as-quenched Cu2MnAl alloy. When the as-quenched alloy was aged at 350 degrees C, gamma-brass precipitates started to appear within the L2(1) matrix. The orientation relationship between the gamma-brass and the L2(1) matrix was determined to be cubic to cubic. This result is consistent with that observed by other workers in the aged Cu-Mn-Al alloy. When the alloy was aged at 460 degrees C, the gamma-brass precipitates disappeared and platelike beta-Mn precipitates occurred within the L2(1) matrix. As the aging temperature was increased to 560 degrees C, the morphology of the beta-Mn precipitates changed from platelike to granular shape. Electron diffraction examinations indicated that in spite of the morphology change the same orientation relationship between the beta-Mn and the L2(1) matrix is maintained, and it could be best stated as follows: (210)(beta-Mn)//(100)(m), ((1) over bar 20)(beta-Mn)//(010)(m), (001)(beta-Mn)/(001)(m) This result is in disagreement with that reported by Kuzobski et al. in the aged Cu2MnAl alloy. In their study, it was concluded that both the morphology of the beta-Mn precipitates and the orientation relationship between the beta-Mn and the L2(1) matrix would vary with the aging temperature.
Phase transformations in a Cu-14.2Al-12.0Ni alloy
(2002-10-11)
Chen, CH
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Liu, TF
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材料科學與工程學系
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Department of Materials Science and Engineering
The as-quenched microstructure of the Cu-14.2Al-12.0Ni alloy was D0(3) phase containing extremely fine L-J precipitates, where the D0(3) phase was formed by an A2 --> B2 --> D0(3) continuous ordering transition during quenching. Besides, the addition of nickel to the Cu-14.2Al binary alloy would raise the B2 --> beta transition temperature. (C) 2002 Acta Materialia Inc. Published by Elsevier Science Ltd. All rights reserved.
Phase transformations in a Cu-14.2Al-7.8Ni alloy
(2003-03-01)
Chen, CH
;
Liu, TF
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工學院
;
材料科學與工程學系
;
College of Engineering
In the as-quenched condition, the microstructure of the Cu-14.2 wt pct Al-7.8 wt pet Ni alloy was D0(3) phase containing extremely fine L-J precipitates with two variants. The L-J precipitate has an orthorhombic structure with lattice parameters a = 0.413 nm, b = 0.254 nm and c = 0.728 nm, which was a new phase found firstly by the present workers. The orientation relationship between the L-J phase and the matrix is (100)(L-J)//(011)(m), (010)(L-J)//(111) and (001)(L-J)//(211)(m). The rotation axis and rotation angle between two variants of the L-J phase are [021] and 90 deg. When the alloy was aged at 500 degreesC for short times and then quenched, gamma(2) particles started to precipitate within the D0(3) matrix at the aging temperature and the remaining D0(3) matrix would transform to gamma(1)' martensite during quenching. This is similar to that observed by other workers in a Cu-14Al-4Ni alloy. However, when the alloy was aged at 500 degreesC for longer times, the remaining D0(3) matrix would transform to a mixture of (B2 + alpha) phases. This feature has never been observed by other workers in the Cu-Al-Ni alloys.
Phase transformations in a Cu-142Al-15.0Ni alloy
(2003-02-17)
Chen, CH
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Liu, TF
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材料科學與工程學系
;
Department of Materials Science and Engineering
In the as-quenched condition, the microstructure of the Cu-14.2Al-15.0Ni alloy was D0(3) phase containing extremely fine L-J precipitates. Since both fine D0(3) domains with a/2(100) anti-phase boundaries (APBs) and small B2 domains with a/4(111) APBs could be observed, the D0(3) phase existing in the as-quenched alloy should be formed by an A2 --> B2 --> D0(3) continuous ordering transition during quenching. It is worthwhile to note that the a/4(111) APBs have never been observed by other workers in the Cu-Al-Ni ternary alloys before. When the as-quenched alloy was aged at temperatures ranging from 400 to 1000 degreesC for longer times, the phase transformation sequence as the aging temperature increased was found to be (alpha + B2 precipitate) --> (B2 + B2 precipitate) --> B2 --> A2. This transformation has also never been observed by other workers in the Cu-Al-Ni ternary alloys before. (C) 2002 Elsevier Science B.V. All rights reserved.
Phase transformations in a Cu-142Al-15.0Ni alloy
(2002-02-17)
Chen, CH
;
Liu, TF
;
材料科學與工程學系
;
Department of Materials Science and Engineering
In the as-quenched condition, the microstructure of the Cu-14.2Al-15.0Ni alloy was D0(3) phase containing extremely fine L-J precipitates. Since both fine D0(3) domains with a/2(100) anti-phase boundaries (APBs) and small B2 domains with a/4(111) APBs could be observed, the D0(3) phase existing in the as-quenched alloy should be formed by an A2 --> B2 --> D0(3) continuous ordering transition during quenching. It is worthwhile to note that the a/4(111) APBs have never been observed by other workers in the Cu-Al-Ni ternary alloys before. When the as-quenched alloy was aged at temperatures ranging from 400 to 1000 degreesC for longer times, the phase transformation sequence as the aging temperature increased was found to be (alpha + B2 precipitate) --> (B2 + B2 precipitate) --> B2 --> A2. This transformation has also never been observed by other workers in the Cu-Al-Ni ternary alloys before. (C) 2002 Elsevier Science B.V. All rights reserved.
Phase transformations in a Cu-25at.%Al-7.5at.%Mn alloy
(2006-03-01)
Yang, SY
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Liu, TF
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材料科學與工程學系
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Department of Materials Science and Engineering
The as-quenched microstructure of the Cu-25at.%Al-7.5at.%Mn alloy was D0(3) phase containing extremely fine L-J precipitates (the L-J phase is a new type of precipitate, which was firstly observed and identified by Liu and Jena (designated L-J phase) in a Cu-2.2-Mn0.8Al alloy.). When the as-quenched alloy was aged at temperatures ranging from 500 degrees C to 700 degrees C, the phase transition sequence was found to be (gamma-brass + L-J + D0(3)) (gamma-brass + L-J + B2) -> beta This result is different from that reported by previous workers in Cu-25at.%Al-(0-8)at.%Mn alloys. (c) 2005 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.
Phase transformations in a Cu-35 at.% Mn-25 at.% Al alloy
(2006-06-29)
Yang, SY
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Liu, TF
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材料科學與工程學系
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Department of Materials Science and Engineering
The phase transformations in the Cu-35 at.% Mn-25 at.% Al alloy have been investigated by means of transmission electron microscopy (TEM) and energy-dispersive X-ray spectrometry (EDS). In as-quenched condition, the microstructure of the alloy was a mixture of (L2(1)+B2+L-J) phases. This is different from that observed by previous workers in the Cu3-xMnxAl alloys with x <= 1.0. When the as-quenched alloy was aged at 460 degrees C for short times, gamma-brass precipitates started to occur at anti-phase boundaries (APBs). After prolonged aging at 460 degrees C, the gamma-brass precipitates grew and beta-Mn precipitates were formed at the regions contiguous to the gamma-brass precipitates. The coexistence of (gamma-brass + beta-Mn) has never been observed by previous workers in Cu-Mn-Al alloy systems before. (c) 2005 Elsevier B.V. All rights reserved.
Phase transformations in an Fe-8Al-10Ni-2C alloy
(2001-02-02)
Lee, JW
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Liu, TF
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材料科學與工程學系
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Department of Materials Science and Engineering
Phase transformations in an Fe-8Al-30Mn-1.5Si-1.5C alloy
(2001-03-01)
Lee, JW
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Liu, TF
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材料科學與工程學系
;
Department of Materials Science and Engineering
The phase transformations in an Fe-8Al-30Mn-1.5Si-1.5C alloy has been investigated by means of transmission electron microscopy. In the as-quenched condition, the microstructure of the alloy was austenite phase containing fine (Fe,Mn)(3)AlC carbides. The fine (Fe,Mn)(3) AlC carbides were formed during quenching by a spinodal decomposition. When the as-quenched alloy was aged at temperatures ranging from 550 to 1000 degreesC, the phase transformation sequence as the aging temperature increased was found to be (Fe,Mn)(3)AlC carbide + D0(3) --> (Fe, Mn)(3)AlC carbide + B2 --> (Fe, Mn)(3)AlC carbide + alpha --> gamma. This transformation has never before been observed in the Fe-Al-Mn-C and Fe-Al-Mn-Si-C alloys. (C) 2001 Elsevier Science B.V. All rights reserved.
Phase transition in a Cu-14.1A1-9.0Ni alloy
(2003-08-15)
Chen, CH
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Yang, CC
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Liu, TF
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材料科學與工程學系
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Department of Materials Science and Engineering
The phase transition of the Cu-14.1 wt.% Al-9.0 wt.% Ni alloy has been examined by transmission electron microscopy and energy-dispersive X-ray analysis. In the as-quenched condition, the microstructure of the alloy was Do(3) phase that contained extremely fine L-J precipitates. During the early stage of isothermal aging at 500 degreesC, a high density of the extremely fine B2 particles was observed within the extremely thin lamellar gamma(1)' martensite, which was formed by a D0(3) --> gamma(1)' martensitic transformation during quenching. With increasing aging time at 500 degreesC, the isothermal phase transition sequence was found to be D0(3) --> D0(3) --> B2 --> D0(3) + B2 + alpha --> B2 + alpha + gamma(2). This transition significantly differs from that observed by other researchers. Besides, both Kurdjumov-Sachs (K-S) and Nishiyama-Wassermann (N-W) orientation relationships between the B2 particle and the alpha phase could be detected in the aged alloy. (C) 2003 Elsevier Science B.V. All rights reserved.
Self-aligned platinum-silicide nanowires for biomolecule sensing
(2005-11-01)
Ko, FH
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Yeh, ZH
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Chen, CC
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Liu, TF
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材料科學與工程學系奈米科技碩博班
A self-aligned platinum-silicide nanowire for biomolecule sensing is developed in this work, The 40 nm nanowire is fabricated through a sequence of electron-beam writing on the polysilicon film, line shrinkage with alkaline solution, platinum film deposition, 550 degrees C annealing, and aqua regia dissolution. The immobilization of single-stranded capture DNA onto the platinum-silicide nanowire is verified from the fluorescence-labeled technique, The field-effect transistor can distinguish the complementary, mismatched, and denatured DNA via the conductance difference. Although the nanowire sensor has not been integrated into a fluid channel system, we can sense the minimal target DNA concentration down to 100 fM, and the signal is still 1000-fold larger than the noise signal. (c) 2005 American Vacuum Society.
Suppression of boron penetration for p(+) stacked poly-Si gates by using inductively coupled N-2 plasma treatment
(1999-10-01)
Cheng, HC
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Lai, WK
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Hwang, CC
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Juang, MH
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Chu, SC
Nitridation of the stacked poly-Si gates by the inductively coupled N-2 plasma (ICNP) treatments has been shown to suppress the boron penetration and improve the gate oxide integrity. The ICNP treatments on the stacked poly-Si layers would create the nitrogen-rich layers not only between the stacked poly-Si layers but also in the gate oxide after post implant anneal, thus resulting in effective retardation of boron diffusion. In addition, the position of ICNP treatment closer to gate oxides leads to higher nitrogen peaks in the gate oxide region, resulting in further suppression of boron penetration and improvement of gate oxide reliability.
The AS-quenched microstructures of Fe-9Al-30Mn-1.2C-xSi alloys
(1997-04-15)
Hwang, CN
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Liu, TF
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材料科學與工程學系
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Department of Materials Science and Engineering