Browsing by Author "Wang, MW"

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3D monochromatic image synthesized with vertical area-partitioned recording of master hologram in multiple-exposure holography
(2001-08-01)
Zhai, HC
;
Mu, GG
;
Wang, MW
;
Liu, FM
;
Pan, D
We report for the first time theoretical analysis and experimental results of a vertical-area partition method for recording master holograms in multiple-exposure rainbow holography to synthesize monochromatic 3D image from a series of medical tomograms. In this novel method, the master hologram is area partitioned into elementary master holograms, which are recorded in a periodic arrangement along the vertical direction. Under the white-light reconstruction, a 3D monochromatic image composed of a series of medical tomograms can be synthesized with wide viewing angle, high resolution, and low color blur. (C) 2001 Published by Elsevier Science B.V.
Accelerated ageing behavior of compatible IPNs based on epoxy and methacrylated epoxy resins
(1998)
Lin, MS
;
Wang, MW
;
Lee, CT
;
Shao, SY
;
應用化學系
Methacrylated diglycidyl ether of bisphenol A (MADGEBA) was synthesized from the reaction of the diglycidyl ether of bisphenol A (DGEBA) and methacrylic acid. The MADGEBA was blended with DGEBA in weight ratios of 100/0, 50/50 and 0/100, and cured simultaneously with dicumyl peroxide (DICUP) and hexahydrophthalic anhydride (HHPA) to obtain interpenetrating polymer networks (IPNs). The three samples were irradiated with ultraviolet in a Q-UVA weatherometer for various periods to study their ageing behavior. Experimental results indicate that the methacryloyl moiety thus incorporated confers significant stabilization against photodegradation. (C) 1998 Elsevier Science Limited. All rights reserved.
An error evaluation technique for the angle of incidence in a rotating element ellipsometer using a quartz crystal
(1999-09-07)
Chao, YF
;
Wang, MW
;
Ko, ZC
;
交大名義發表
;
National Chiao Tung University
The error in the angle of incidence for a rotating element ellipsometer is evaluated using a uniaxial quartz crystal. At a fixed angle of incidence with respect to the surface of reflection, the ratio of reflectance in the parallel to that in the perpendicular electromagnetic field is measured by rotating the quartz crystal through a full cycle. We determine the deviation in the angle of incidence by comparing: the experimentally measured reflectance ratio to its calculated value.
Azimuth alignment in photoelastic modulation ellipsometry at a fixed incident angle
(2002-06-01)
Wang, MW
;
Chao, YF
;
光電工程學系
;
Department of Photonics
A high intensity ratio technique is proposed to align all the azimuthal angles of a photoelastic modulation ellipsometric system in a fixed incident angle. This technique is used to determine the azimuthal orientations of the polarizer, the photoelastic modulator and the analyzer to the incident plane, Two pre-designed testing samples and two probing wavelengths for a thin film are introduced to locate the incident plane by the intensity ratio technique in a polarizer-sample-analyzer ellipsometric setup. Then, the azimuth of the pholoelastic modulator is directly obtained from two DC radiances separated by 45degrees. In addition to azimuth deviation, the ellipsometric parameter psi can also be determined from the same measurement for determining the incident angle on-line.
Calibrations of phase modulation amplitude of photoelastic modulator
(2004-02-01)
Wang, MW
;
Chao, YF
;
Leou, KC
;
Tsai, FH
;
Lin, TL
A multiple harmonic intensity ratio technique is proposed for calibrating the modulation amplitude (Delta(0)) of a photoelastic modulator (PEM). A data acquisition system is utilized to investigate the frequency response of this technique. Delta(0) determined by this technique is independent of frequency, which is proved using the reflection and transmission setups. In addition to confirm our calibration using the digitized oscilloscope waveform, we also obtain a set of ellipsometric parameters under various values of Delta(0) before and after calibration. We also introduce a correction factor to correct the effect caused by the shift of the modulation amplitude in the process of etching. An optical thick film is used to calibrate Delta(0) using PEM ellipsometry, and its refractive index and extinction coefficient are also obtained in etching. Finally, we suggest the use of the traces of the ellipsometric parameters under various thicknesses for monitoring instead of calculating the thickness in real time.
Curing behaviour of compatible interpenetrating polymer networks based on epoxy and methacrylated epoxy
(1997-12-01)
Wang, MW
;
Lee, CT
;
Lin, MS
;
應用化學系
;
Department of Applied Chemistry
Compatible interpenetrating polymer networks (IPNs) based on diglycidyl ether of bisphenol A (DGEBA) and methacrylated diglycidyl ether of bisphenol A (MADGEBA) in weight ratios of 100/0, 75/25, 50/50, 25/75 and 0/100 were blended and cured simultaneously by using dicumyl peroxide (DICUP) and hexahydrophthalic anhydride (HHPA) as curing agents. Fourier transform infrared spectroscopy (FTIR) was employed to investigate the intermolecular interactions and functional group changes. Viscosity increases during crosslinking were examined with a Brookfield viscometer. Curing exothermic peaks were studied with differential scanning calorimetry (DSC). The gel fractions of various IPN compositions were measured with a Soxhlet extractor. Samples thus prepared were checked for their compatibility by measuring glass transitions with DSC and damping peaks with rheometric dynamic spectroscopy (RDS). Experimental results revealed that good compatibility between components induced a network interlock, which subsequently resulted in incomplete cure of the IPN materials.
In situ calibration technique for photoelastic modulator in ellipsometry
(2004-05-01)
Wang, MW
;
Tsai, FH
;
Chao, YF
;
光電工程學系
;
Department of Photonics
The modulation amplitude of a phase modulator is calibrated under a fixed incident angle in photoelastic modulation (PEM) ellipsometry. In addition to its modulation amplitude (Delta(o)), we also calibrated its static phase retardation at 632.8 nm. The ellipsometric parameters of a sample were measured by a multiple harmonic intensity ratio technique and proved that ellipsometric parameters can be obtained under various modulation amplitudes. Since the physical size of PEM is constant, we calibrated the modulation amplitude at multiple wavelengths by setting the Delta(o) value at 0.383 for 568.2 nm. These calibrations provided enough information for establishing an in situ/real time spectroscopic ellipsometry. (C) 2003 Elsevier B.V. All rights reserved.
Kinetic study on epoxy bisphenol-A diacrylate IPN formation
(1999-12-01)
Lin, MS
;
Wang, MW
;
應用化學系
;
Department of Applied Chemistry
Interpenetrating polymer networks (IPN) based on diglycidyl ether of bisphenol-A (DGEBA) and bishenol-A diacrylate (BADA) in weight ratios of 100/0, 50/50, and 0/100 were blended and were cured simultaneously by using benzoyl peroxide (BPO) and 4,4'-methylenedianiline (MDA) as curing agents. Kinetic study during IPN formation was carried out at 65, 70, 75 and 80 degrees C. Absorbance changes at 1623.3 cm(-1) and 914 cm(-1) relating to concentration changes of C=C and epoxide were monitored with Fourier-transform infrared spectroscopy (FTIR). The epoxide cure kinetic data revealed a combination of non-catalytic bimolecular reaction and a catalyzed termolecular reaction, while the C=C cure kinetic data fitted a first-order reaction. The calculated kinetic parameters indicated decreased rate constants and increased activation energies of the IPN compared with those of the individual components. Presumably, chain entanglements between the two networks provide a sterically hindered environment for the cure reactions and vitrification restrains the chain mobility, accounting for the kinetic parameters. (C) 1999 Society of Chemical Industry.
Photoelastic modulation polarimetry and its measurement of twisted nematic liquid crystal
(2001)
Chao, YF
;
Lin, A
;
Wang, MW
;
光電工程學系
;
Department of Photonics
For in situ/real time measurement, a retarder is substituted by a photoelastic modulator (PEM) in a polarimetry. The azimuthal position of the strain axis of PEM is directly determined with respect to the orientation of the transmission axis of polarizer and analyzer. The Mueller matrix of a twisted nematic liquid crystal (TN-LCD) is derived analytically. The phase retardation and the twisted angle of a TN-LCD are numerically obtained through two successive measurements of the Mueller polarimeter.
Photostabilization of an epoxy resin by forming interpenetrating polymer networks with bisphenol-A diacrylate
(1999)
Lin, MS
;
Wang, MW
;
Cheng, LA
;
應用化學系
;
Department of Applied Chemistry
Bisphenol-A diacrylate (BADA) was synthesized from the reaction of bisphenol-A and acrylol chloride. Interpenetrating polymer networks (IPNs) based on diglycidyl ether of bisphenol-A. (DGEBA) and BADA in weight ratios of DGEBA/BADA = 100/0, 75/25 and 50/50 were prepared by using 4,4'-diaminodiphenylmethane (MDA) and benzoyl peroxide (BPO) as curing agents. Samples were irradiated with ultraviolet in a Q-WA weather-o-meter to study their aging behavior. Experimental results indicated that the BADA thus incorporated in the IPN structure confers significant photostabilization of the epoxy, as shown by less chain scission at C-O-C in the epoxy, with less property loss in mechanical tests. (C) 1999 Elsevier Science Ltd. All rights reserved.
Siloxane- and imide-modified epoxy resin cured with siloxane-containing dianhydride
(2005-10-01)
Li, HT
;
Lin, MS
;
Chuang, HR
;
Wang, MW
;
應用化學系
Hydrosilylation of nadic anhydride by tetramethyldisiloxane yielded 5,5'-(1, 1,3,3-tetramethyl- 1, 1,3,3-disiloxanediayl)-bisnorborane-2,3-dicarboxylic anhydride (I), which further reacted with 4-aminophenol to form N,N'-bis(4-hydroxyphenyl)5,5'-(1,1,3,3-tetramethyl-1,1,3,3-disiloxanediallyl)-binorborane-2,3-dicarboximide(II) reacted with epichlorohydrin to form siloxane- and imide-modified epoxy (i.e. N,N'-diglycidylether-bis-(4-phenyl)-5,5'-(1,1,3,3-tetramethyl-1,1,3,3disloxanediallyl)-bis-norborane-2,3-dicarboximide (III) (Scheme 1). Various equivalent ratios of III/I for 1/1, 1/0.8 and Bisphenol F epoxy (830LVP DIC Co.)/I for 1/1, 1/0.8 were prepared and cured to produce four crosslinked materials. Thermal and dynamic mechanical properties were measured with TMA and DMA. Kinetic analysis was studied with dynamic DSC, which revealed a relatively lower curing activation energy of III/I systems, because the tertiary amine on the imide group catalyzed the curing reaction. III/I system also indicated moderate Tg, storage modulus but higher loss modulus as compared with Bisphenol F epoxy/I systems. These phenomena were interpreted by the fact that the siloxane group in III toughened the crosslinked materials. In addition, photos of SEM, carbon-mapping-SEM, oxygen-mapping SEM and siloxane-mapping-SEM indicated all homogeneity of these materials.
Synthesis, properties and pyrolysis of siloxane- and imide-modified epoxy resin cured with siloxane-containing dianhydride
(2005-10-01)
Li, HT
;
Chuang, HR
;
Wang, MW
;
Lin, MS
;
應用化學系
Hydrosilylation of nadic anhydride with tetramethyl disiloxane yielded 5,5'-(1,1,3,3-tetramethyl disiloxane-1,3-diyl)-bis-norborane-2,3-dicarboxylic anhydride (1), which further reacted with 4-aminophenol to give N,N'-bis(4-hydroxyphenyl)-5,5'-bis-(1,1,3,3-tetramethyl disiloxane-1,3-diyl)-bisnorborane-2,3-dicarboximide (II). Epoxidation of II with excess epichlorohydrin formed a siloxane-and imide-modified epoxy oligomer (ie diglycidyl ether of N,N'-bis(4-hydroxyphenyl)-5,5'-bis(1,1,3,3-tetramethyl disiloxane-1,3-diyl)-bis-norborane-2,3-dicarboximide) (III). Equivalent ratios of IIIII of 1/1 and 1/0.8 were prepared and cured to produce crosslinked materials. Thermal mechanical and dynamic mechanical properties were investigated by TMA and DMA, respectively. It was noted that each of these two materials showed a glass transition temperature (T-g) higher than 160 degrees C with moderate moduli. The thermal degradation kinetics was studied with dynamic thermogravimetric analysis (TGA) and the estimated apparent activation energies were 111.4 kJ mol(-1) (in N-2), 117.1 kJ mol(-1) (in air) for III/I = 1/0.8, and 149.2 kJ mol(-1) (in N-2), 147.6 kJ mol(-1) (in air) for III/I = 1/1. The white flaky residue of the TGA char was confirmed to be silicon dioxide, which formed a barrier at the surface of the polymer matrix and, in part, accounted for the unique heat resistance of this material. (c) 2005 Society of Chemical Industry.
Viewing effects of 3-D images synthesized from a series of 2-D tomograms by VAP and HAP approaches
(2002)
Zhai, HC
;
Wang, MW
;
Liu, FM
;
Hsu, KY
;
光電工程學系
We report, for the first time, the experimental result and its analysis of synthesizing a series of simulating 2-D tomograms into a 3-D monochromatic image. Our result shows clearly the advantage in monochromaticity of a vertical area-partition (VAP) approach over a horizontal area-partition (HAP) approach during the final white-light reconstruction. This monochromaticity will ensure a 3-D image synthesis without any distortion in gray level or positional recovery.