The structure and dielectric properties of （Pb,Sr）Nb2O6-NaNbO3-SiO2 glass-ceramics with different Pb and Sr contents were investigated. The XRD pattern of glass-ceramics without Sr substitution is different from tha...The structure and dielectric properties of （Pb,Sr）Nb2O6-NaNbO3-SiO2 glass-ceramics with different Pb and Sr contents were investigated. The XRD pattern of glass-ceramics without Sr substitution is different from that with Sr substitution, which indicates the existence of orthorhombic phase in the latter ones. TEM bright field observation shows nanosized microstructures, while for samples with Sr, typical eutectic microstrncture with separated crystallized bands is found in the glass matrix. Dielectric properties measurement of the samples indicates an obvious improvement of dielectric constant, dielectric loss, DC field and temperature dependence of dielectric constant when the molar ratio of Sr to Pb is 4：6.展开更多
A fully automated atomic force microscope(AFM)is presented.The mechanical motion of the AFM stage was controlled by three steppers.The fine motion of the AFM was controlled by an MCL one-axis piezo plate.A32.768kHz cr...A fully automated atomic force microscope(AFM)is presented.The mechanical motion of the AFM stage was controlled by three steppers.The fine motion of the AFM was controlled by an MCL one-axis piezo plate.A32.768kHz crystal tuning fork(TF)was used as the transducer with a probe attached.An acoustic sensor was used to measure the interactions between the probe and the sample.An SR850lock-in amplifier was used to monitor the TF signals.An additional lock-in amplifier was used to monitor the acoustic signal.A field programmable gate array(FPGA)board was used to collect the data in automatic mode.The main controller was coded with LabVIEW,which was in charge of Z-axis scan,signal processing and data visualization.A manual mode and an automatic mode were implemented in the controller.Users can switch the two modes at any time during the operation.This AFM system showed several advantages during the test operations.It is simple,flexible and easy to use.展开更多
文摘The structure and dielectric properties of （Pb,Sr）Nb2O6-NaNbO3-SiO2 glass-ceramics with different Pb and Sr contents were investigated. The XRD pattern of glass-ceramics without Sr substitution is different from that with Sr substitution, which indicates the existence of orthorhombic phase in the latter ones. TEM bright field observation shows nanosized microstructures, while for samples with Sr, typical eutectic microstrncture with separated crystallized bands is found in the glass matrix. Dielectric properties measurement of the samples indicates an obvious improvement of dielectric constant, dielectric loss, DC field and temperature dependence of dielectric constant when the molar ratio of Sr to Pb is 4：6.
文摘A fully automated atomic force microscope(AFM)is presented.The mechanical motion of the AFM stage was controlled by three steppers.The fine motion of the AFM was controlled by an MCL one-axis piezo plate.A32.768kHz crystal tuning fork(TF)was used as the transducer with a probe attached.An acoustic sensor was used to measure the interactions between the probe and the sample.An SR850lock-in amplifier was used to monitor the TF signals.An additional lock-in amplifier was used to monitor the acoustic signal.A field programmable gate array(FPGA)board was used to collect the data in automatic mode.The main controller was coded with LabVIEW,which was in charge of Z-axis scan,signal processing and data visualization.A manual mode and an automatic mode were implemented in the controller.Users can switch the two modes at any time during the operation.This AFM system showed several advantages during the test operations.It is simple,flexible and easy to use.
