Yanhua PANG
,
Wei FENG
,
Jie CHEN
,
Yan LIU
,
Weimin CAI
材料科学技术（英文）
A series of inorganic-organic thin films based on uniformly dispersed nanoparticles of polyoxometalates (POM) entrapped in polyacrylamide (PAM) matrix were prepared by ultrasonic method with different irradiation time. The microstructure, photochromic behavior and mechanism of the films were studied by transmission electron microscopy (TEM), ultraviolet-visible spectra (UV-VIS) and Fourier transform-infrared spectroscopy (FT-IR). The microstructure and photochromic properties of the hybrid thin films could be controlled by ultrasound. TEM image revealed that the average size of phosphotungstic acid (PWA) nanoparticles decreased from 20 to 10 nm with the ultrasound irradiation time from 30 to 60 min. After irradiated with ultraviolet light, the transparent films changed from colorless to blue and showed reversible photochromism. The hybrid film, with ultrasound irradiation for 60 min had higher photochromic efficiency and faster bleaching reaction than the one with ultrasound irradiation for 30 min. FT-IR spectra showed that the Keggin geometry of heteropolyoxometalate was still preserved inside the composites, and the interactions between polyanions and polymer matrix increased as the ultrasound time prolonged. It is suggested that the mechanism of the different photochromic properties for the inorganic-organic thin films is the variation of the microstructure and interfacial interactions induced by ultrasound.
关键词:
sonochemical
,
null
,
null
,
null
Li XING
,
Jie ZHAO
,
Fuzhong SHEN
,
Wei FENG
材料科学技术（英文）
A Z-parameter method is used to evaluate the damage process of HK40 austenitic steel. By using Z-parameter based on the Larson-Miller method, the nonlinear master curve of the log stress vs Larson-Miller parameter P can be expressed as: P=27.74-3.4lgσ-0.032σ, and a family of curves parallel to the master curve can be written as: P=(27.74-Z)-3.4lgσ-0.032σ, where Z represents the magnitude of the deviation from the master curve. According to the creep rupture data both from different segments of a serviced tube and from the same segment locations with different service time, the value of parameter Z has close relationship with the deterioration of creep rupture properties. The damage state of the samples is evaluated by monitoring the changes in natural frequency f and Young0s modulus E, and the relationships between Z and the damage parameters are discussed.
关键词:
Damage evaluation
,
蠕变断裂
,
奥氏体钢
,
Z参数
Lizhi CHENG
,
Wei FENG
,
Xinquan DONG
,
Kuichang BAI and Kaiyuan HE (Dept. of Materials Science and Engineering
,
Northeastern University Shenyang 110006
,
China)
材料科学技术（英文）
The formation of nonequilibrium phase by mechanical alloying (MA) of Fe and B powders in a high energy vibration ball mill has been made for Fe100-xBx system with x=15. 30, 35, 45,55 and 70. By using the X-ray diffraction, magnetic measurement and M6ssbauer spectrummethods, it was revealed that the structure of the MA product varies with milling time and B contents.
关键词:
