An alternate non-Fourier heat conduction equation is derived from consideration of translation motion of spinless electron under a driving force due to an applied temperature gradient. This equation is a eapite ad cal...An alternate non-Fourier heat conduction equation is derived from consideration of translation motion of spinless electron under a driving force due to an applied temperature gradient. This equation is a eapite ad calcem,temperature. Elimination of the rate of change of velocity with respect to time leads to a non-Fourier heat conduction equation with a accumulation of temperature or ballistic term in it. The new constitutive heat conduction equation is combined with the energy balance equation in one dimension. The governing equation for transient temperature a partial differential equation （Eq. （23）） is solved for by the method of Laplace transforms. The problem considered is the semi-infinite medium with constant thermo physical properties with constant wall temperature boundary condition. A closed form analyticalexpression for the transient temperature was obtained （Eq. （36）） after truncation of higher order terms in the infinite binomial series and use of convolution and lag properties. This solution is compared with that obtained using the parabolic Fourier model and the damped wave model as presented in an earlier study. The predictions of Eq. （36） are closer to the Fourier model. The convex nature of the temperature curve is present.展开更多
The prediction method of dynamic wavelength is proposed for temperature tuning process. The temperature of the thermistor integrated in laser diode(LD) module is recorded to predict the LD chip temperature. Then accor...The prediction method of dynamic wavelength is proposed for temperature tuning process. The temperature of the thermistor integrated in laser diode(LD) module is recorded to predict the LD chip temperature. Then according to the injection current and priori tuning characteristics of the LDs, the emission wavelength is estimated in real time. The method is validated by using a 1.58 μm distributed feedback(DFB) LD. The absorption spectra of mixture gas of CO_2 and CO are measured by means of the thermal tuning gas sensing system. The center wavelength of each absorption line is compared with the data in HITRAN2012 database. The results show that the deviations are less than 5 pm. This method fully meets the needs of spectroscopic measurement, and can be applied to spectroscopy, optical communications and other fields.展开更多
文摘An alternate non-Fourier heat conduction equation is derived from consideration of translation motion of spinless electron under a driving force due to an applied temperature gradient. This equation is a eapite ad calcem,temperature. Elimination of the rate of change of velocity with respect to time leads to a non-Fourier heat conduction equation with a accumulation of temperature or ballistic term in it. The new constitutive heat conduction equation is combined with the energy balance equation in one dimension. The governing equation for transient temperature a partial differential equation （Eq. （23）） is solved for by the method of Laplace transforms. The problem considered is the semi-infinite medium with constant thermo physical properties with constant wall temperature boundary condition. A closed form analyticalexpression for the transient temperature was obtained （Eq. （36）） after truncation of higher order terms in the infinite binomial series and use of convolution and lag properties. This solution is compared with that obtained using the parabolic Fourier model and the damped wave model as presented in an earlier study. The predictions of Eq. （36） are closer to the Fourier model. The convex nature of the temperature curve is present.
基金supported by the National Natural Science Foundation of China(No.61505142)the Tianjin Natural Science Foundation(No.16JCQNJC02100)
文摘The prediction method of dynamic wavelength is proposed for temperature tuning process. The temperature of the thermistor integrated in laser diode(LD) module is recorded to predict the LD chip temperature. Then according to the injection current and priori tuning characteristics of the LDs, the emission wavelength is estimated in real time. The method is validated by using a 1.58 μm distributed feedback(DFB) LD. The absorption spectra of mixture gas of CO_2 and CO are measured by means of the thermal tuning gas sensing system. The center wavelength of each absorption line is compared with the data in HITRAN2012 database. The results show that the deviations are less than 5 pm. This method fully meets the needs of spectroscopic measurement, and can be applied to spectroscopy, optical communications and other fields.
