相变偶氮苯衍生物可以基于异构化储存和释放热量.热量输出量和速率受偶氮苯结晶和异构化的影响,同时也受分子结构和相互作用的制约.因此,优化分子结构是控制不同温度下热量释放的一种有效方式.在此,我们制备了三个不对称的烷氧基取代的...相变偶氮苯衍生物可以基于异构化储存和释放热量.热量输出量和速率受偶氮苯结晶和异构化的影响,同时也受分子结构和相互作用的制约.因此,优化分子结构是控制不同温度下热量释放的一种有效方式.在此,我们制备了三个不对称的烷氧基取代的偶氮苯分子(sAzo),其分子量相似但取代基不同,以研究结晶和异构化之间的权衡.我们研究了s-Azo的温控结晶性和光诱导的异构化动力学.结果表明,由于较强的范德华力,正烷氧基取代使s-Azo具有较高的结晶焓(ΔHCE),但立体阻碍降低了异构化程度.短烷基支化降低了分子相互作用,有利于异构化,使异构化焓(ΔHIE)增加,但降低了ΔHCE.正烷氧基取代的sAzo在-60.49至34.76℃的宽温度范围内表现出光诱导的高能热释放,焓值高达343.3 J g^(-1),功率密度为413 W kg^(-1).同步放热使分布式能量利用的环形装置在低温环境(-5℃)下实现了6.3℃的温升.结果表明,相变偶氮苯衍生物可以通过优化分子结构和相互作用应用于理想的储能系统.展开更多
Pressure sensors based on fiber-optic extrinsic Fabry-Perot interferometer(EFPI)have been extensively applied in various industrial and biomedical fields.In this paper,some key improvements of EFPI-based pressure sens...Pressure sensors based on fiber-optic extrinsic Fabry-Perot interferometer(EFPI)have been extensively applied in various industrial and biomedical fields.In this paper,some key improvements of EFPI-based pressure sensors such as the controlled thermal bonding technique,diaphragm-based EFPI sensors,and white light interference technology have been reviewed.Recent progress on signal demodulation method and applications of EFPI-based pressure sensors has been introduced.Signal demodulation algorithms based on the cross correlation and mean square error(MSE)estimation have been proposed for retrieving the cavity length of EFPI.Absolute measurement with a resolution of 0.08 nm over large dynamic range has been carried out.For downhole monitoring,an EFPI and a fiber Bragg grating(FBG)cascade multiplexing fiber-optic sensor system has been developed,which can operate in temperature 300℃with a good long-term stability and extremely low temperature cross-sensitivity.Diaphragm-based EFPI pressure sensors have been successfully used for low pressure and acoustic wave detection.Experimental results show that a sensitivity of 31 mV/Pa in the frequency range of 100 Hz to 12.7 kHz for aeroacoustic wave detection has been obtained.展开更多
The effect of pre-deformation on nanoscale precipitates and hardness of a maraging stainless steel strengthened by the coprecipitation of Ni_(3)Ti,Mo-enriched and Cr-enriched precipitates was systematically studied us...The effect of pre-deformation on nanoscale precipitates and hardness of a maraging stainless steel strengthened by the coprecipitation of Ni_(3)Ti,Mo-enriched and Cr-enriched precipitates was systematically studied using electron back scattered diffraction,transmission electron microscopy and atom probe tomography(APT).Hardness measurements showed that the hardness of specimen with a deformation ratio of 90%peaked at HV 718 aged for 24 h,which is higher than that in the undeformed specimen(HV 603)aged for 72 h at 480℃.APT characterization revealed that pre-deformation could shorten the incubation time of the Mo-enriched and Cr-enriched precipitates.At the early-aged stage,pre-deformation increased the stain energy that inhibited the nucleation of Ni_(3)Ti precipitates,but accelerated the rejection of Mo from Ni-Ti clusters.Besides,the strengthening model indicated that strain hardening(43%)makes a larger contribution to the hardness at the early-aged condition,while precipitation hardening(58%)has most contribution to the hardness at the peak-aged conditition.展开更多
基金financially supported by the National Key R&D Program of China (2022YFB3805702)the State Key Program of National Natural Science Foundation of China (51973152 and 52130303)the Science Foundation for Distinguished Young Scholars in Tianjin (19JCJQJC61700)。
文摘相变偶氮苯衍生物可以基于异构化储存和释放热量.热量输出量和速率受偶氮苯结晶和异构化的影响,同时也受分子结构和相互作用的制约.因此,优化分子结构是控制不同温度下热量释放的一种有效方式.在此,我们制备了三个不对称的烷氧基取代的偶氮苯分子(sAzo),其分子量相似但取代基不同,以研究结晶和异构化之间的权衡.我们研究了s-Azo的温控结晶性和光诱导的异构化动力学.结果表明,由于较强的范德华力,正烷氧基取代使s-Azo具有较高的结晶焓(ΔHCE),但立体阻碍降低了异构化程度.短烷基支化降低了分子相互作用,有利于异构化,使异构化焓(ΔHIE)增加,但降低了ΔHCE.正烷氧基取代的sAzo在-60.49至34.76℃的宽温度范围内表现出光诱导的高能热释放,焓值高达343.3 J g^(-1),功率密度为413 W kg^(-1).同步放热使分布式能量利用的环形装置在低温环境(-5℃)下实现了6.3℃的温升.结果表明,相变偶氮苯衍生物可以通过优化分子结构和相互作用应用于理想的储能系统.
文摘Pressure sensors based on fiber-optic extrinsic Fabry-Perot interferometer(EFPI)have been extensively applied in various industrial and biomedical fields.In this paper,some key improvements of EFPI-based pressure sensors such as the controlled thermal bonding technique,diaphragm-based EFPI sensors,and white light interference technology have been reviewed.Recent progress on signal demodulation method and applications of EFPI-based pressure sensors has been introduced.Signal demodulation algorithms based on the cross correlation and mean square error(MSE)estimation have been proposed for retrieving the cavity length of EFPI.Absolute measurement with a resolution of 0.08 nm over large dynamic range has been carried out.For downhole monitoring,an EFPI and a fiber Bragg grating(FBG)cascade multiplexing fiber-optic sensor system has been developed,which can operate in temperature 300℃with a good long-term stability and extremely low temperature cross-sensitivity.Diaphragm-based EFPI pressure sensors have been successfully used for low pressure and acoustic wave detection.Experimental results show that a sensitivity of 31 mV/Pa in the frequency range of 100 Hz to 12.7 kHz for aeroacoustic wave detection has been obtained.
基金sponsored by the Youth Innovation Promotion Association of Chinese Academy of Sciences(No.2017233)。
文摘The effect of pre-deformation on nanoscale precipitates and hardness of a maraging stainless steel strengthened by the coprecipitation of Ni_(3)Ti,Mo-enriched and Cr-enriched precipitates was systematically studied using electron back scattered diffraction,transmission electron microscopy and atom probe tomography(APT).Hardness measurements showed that the hardness of specimen with a deformation ratio of 90%peaked at HV 718 aged for 24 h,which is higher than that in the undeformed specimen(HV 603)aged for 72 h at 480℃.APT characterization revealed that pre-deformation could shorten the incubation time of the Mo-enriched and Cr-enriched precipitates.At the early-aged stage,pre-deformation increased the stain energy that inhibited the nucleation of Ni_(3)Ti precipitates,but accelerated the rejection of Mo from Ni-Ti clusters.Besides,the strengthening model indicated that strain hardening(43%)makes a larger contribution to the hardness at the early-aged condition,while precipitation hardening(58%)has most contribution to the hardness at the peak-aged conditition.
