Browsing by Author "Li, HT"

Now showing 1 - 3 of 3

Application studies of a simulated low density room-temperature IRFPA
(1998)
Lee, TS
;
Shie, JS
;
Li, HT
;
光電工程學系
;
Department of Photonics
Recent developed thermal imagers using room-temperature IRFPA detectors have stimulated great opportunity in many commercial applications. This paper studies the possibility of using a low-density array detector for low-cost security-and-fire applications. Features on human body and plume were extracted by their infrared signatures. The human information was obtained from his spatial distribution, while a hazardous plume was supplemented with an additional temporal distribution. The function of a smaller array (less than or equal to 64x64) sensor was implemented by a high-resolution (320x240) commercial uncooled system through image downward re-sampling and pre-processing. Trade-off study between the recognition accuracy and the array size are also analyzed.
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.