To explore the effects of thermal treatment on cracking processes in granite, granite samples were thermally treated at 25-400 ℃ and then loaded under uniaxial compression. Active ultrasonic testing and passive acous...To explore the effects of thermal treatment on cracking processes in granite, granite samples were thermally treated at 25-400 ℃ and then loaded under uniaxial compression. Active ultrasonic testing and passive acoustic emission(AE) monitoring were combined to monitor the damage characteristics of the samples. The uniaxial compression strength(UCS) of the sample treated at 200 ℃ shows no apparent change compared with that of the nonheated sample, while the UCS increases at 300 °C and decreases at 400 ℃. As the temperature increases from 25 to 400 ℃, the initial P-wave velocity(Vp) decreases gradually from 4909 to 3823 m/s, and the initial Vpanisotropy ε increases slightly from 0.03 to 0.09. As the axial stress increases, ε increases rapidly in the crack closure stage and unstable cracking stage. The attenuation of ultrasonic amplitude spectra also shows an obvious anisotropy. Besides, the main location magnitude of AE events decreases after thermal treatment, and low-frequency AE events and high-amplitude AE events increasingly occur. However, there is insufficient evidence that the treatment temperature below 400 ℃ has a significant effect on the temporal characteristics, source locations, and b-values of AE.展开更多
Tetraphenylethene (TPE) is a popular luminogen characterized by aggregation-induced emission and has been widely used to construct solid-state emissive materials. In this work, two thermally stable polymers (P1 and P2...Tetraphenylethene (TPE) is a popular luminogen characterized by aggregation-induced emission and has been widely used to construct solid-state emissive materials. In this work, two thermally stable polymers (P1 and P2) consisting of TPE conjugated to the 2,7-positions of fluorene and carbazole, respectively, are synthesized and characterized. Both polymers are weakly fluorescent in solutions but show greatly enhanced emission as the aggregate formation, presenting an aggregation-enhanced emission feature. Two kinds of polymer light-emitting diodes are fabricated utilizing P1 and P2 as emitters (EML) (device I: ITO/PEDOT:PSS (45 nm)/PVK:EML (1:1 wt%, 55 nm)/TPBI (38 nm)/Ca:Ag; device II: ITO/PEDOT:PSS (45 nm)/ PVK:OXD-7:EML (3:1:3 wt%, 55 nm)/TPBI (38 nm)/Ca:Ag). The device II of P2 shows the best performances, affording a maximum luminance of 6500 cd/m 2 and a high peak efficiency of 2.11 cd/A.展开更多
The generator is the starter device of single stage heat transformer(SSHT) and its characteristics have main effects on the overall efficiency of this kind of absorption machines.This article reports a study of the ge...The generator is the starter device of single stage heat transformer(SSHT) and its characteristics have main effects on the overall efficiency of this kind of absorption machines.This article reports a study of the generation of steam and changes in the concentration of the working solution(Water/Carrol mixture) into a plate heat exchanger as a function of its horizontal and vertical position by gravity effect.It is considered the analysis of six experimental tests;two were evaluated in a plate heat exchanger in a horizontal position and four in a vertical position(90 degree inclination).The generation of steam and increased concentration of the working solution are more sensitive to the vertical position of exchanger than in horizontal position.The results of numerical-experimental analysis indicates that a heat exchanger in horizontal position,the steam generation and the change in the concentration of the working solution occurring in the middle of the plate(or at greater distance depending to the thermodynamic conditions) and instantly in vertical position(at the input of the plate).展开更多
基金Project(51934003) supported by the National Natural Science Foundation of China,ChinaProject(202105AE160023) supported by the Yunnan Innovation Team,China。
文摘To explore the effects of thermal treatment on cracking processes in granite, granite samples were thermally treated at 25-400 ℃ and then loaded under uniaxial compression. Active ultrasonic testing and passive acoustic emission(AE) monitoring were combined to monitor the damage characteristics of the samples. The uniaxial compression strength(UCS) of the sample treated at 200 ℃ shows no apparent change compared with that of the nonheated sample, while the UCS increases at 300 °C and decreases at 400 ℃. As the temperature increases from 25 to 400 ℃, the initial P-wave velocity(Vp) decreases gradually from 4909 to 3823 m/s, and the initial Vpanisotropy ε increases slightly from 0.03 to 0.09. As the axial stress increases, ε increases rapidly in the crack closure stage and unstable cracking stage. The attenuation of ultrasonic amplitude spectra also shows an obvious anisotropy. Besides, the main location magnitude of AE events decreases after thermal treatment, and low-frequency AE events and high-amplitude AE events increasingly occur. However, there is insufficient evidence that the treatment temperature below 400 ℃ has a significant effect on the temporal characteristics, source locations, and b-values of AE.
基金the National Natural Science Foundation of China (51273053, 21104012, 21284034 and 61106017)the Natural Science Foundation of Zhejiang Province (Y4110331)+1 种基金the Program for Changjiang Scholars and Innovative Research Teams in Chinese Universities (IRT 1231)the Project of Zhejiang Key Scientific and Technological Innovation Team (2010R50017)
文摘Tetraphenylethene (TPE) is a popular luminogen characterized by aggregation-induced emission and has been widely used to construct solid-state emissive materials. In this work, two thermally stable polymers (P1 and P2) consisting of TPE conjugated to the 2,7-positions of fluorene and carbazole, respectively, are synthesized and characterized. Both polymers are weakly fluorescent in solutions but show greatly enhanced emission as the aggregate formation, presenting an aggregation-enhanced emission feature. Two kinds of polymer light-emitting diodes are fabricated utilizing P1 and P2 as emitters (EML) (device I: ITO/PEDOT:PSS (45 nm)/PVK:EML (1:1 wt%, 55 nm)/TPBI (38 nm)/Ca:Ag; device II: ITO/PEDOT:PSS (45 nm)/ PVK:OXD-7:EML (3:1:3 wt%, 55 nm)/TPBI (38 nm)/Ca:Ag). The device II of P2 shows the best performances, affording a maximum luminance of 6500 cd/m 2 and a high peak efficiency of 2.11 cd/A.
基金supporting basic science project 167434:"Analysis of waste energy recovery and sustainable development"
文摘The generator is the starter device of single stage heat transformer(SSHT) and its characteristics have main effects on the overall efficiency of this kind of absorption machines.This article reports a study of the generation of steam and changes in the concentration of the working solution(Water/Carrol mixture) into a plate heat exchanger as a function of its horizontal and vertical position by gravity effect.It is considered the analysis of six experimental tests;two were evaluated in a plate heat exchanger in a horizontal position and four in a vertical position(90 degree inclination).The generation of steam and increased concentration of the working solution are more sensitive to the vertical position of exchanger than in horizontal position.The results of numerical-experimental analysis indicates that a heat exchanger in horizontal position,the steam generation and the change in the concentration of the working solution occurring in the middle of the plate(or at greater distance depending to the thermodynamic conditions) and instantly in vertical position(at the input of the plate).
