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根据吊环法测量液体表面张力系数实验原理,针对现有的FD-NST-1型液体表面张力系数测量仪的不足进行改进.另外在仪器上增加样品加热装置,可以对不同温度下的液体表面张力系数进行测量.通过实验对比得出:改进后的实验装置操作方便、实验误差小,重复性好. 相似文献
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对拉脱法测表面张力系数实验数据进行了详细的不确定度计算,在常温下测量结果精度较好。在变温下进行了单次测量,由于仪器控温装置精度较低以及表面张力系数随温度变化较小,每个温度点的测量值存在一定偏差,但实验结果的变化趋势基本一致。 相似文献
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对用力敏传感器测量液体表面张力系数仪器进行研究,重新设计了吊环,便于吊环的水平调节,对待侧液体表面均匀下降的方法和实验装置做了重新设计,减小了实验误差,同时增加了待测液体的变温控制,能够精确测量液体表面张力系数与温度的关系,扩充了实验内容. 相似文献
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Due to the deformation of electronic charge clouds, the Dick-Overhauser exchange charge in ionic materials is shown to have quadratic temperature dependence as T tends to zero in non-centrosymmetric crystals. It follows that the pyroelectric coefficient π has a linear temperature dependence in the same low temperature limit. The order of magnitude of π obtained theoretically by a simple model at T = 5 K is 2 × 10?7 μC cm?2 K?1, which is in fairly good agreement with that obtained experimentally on LiTaO3 by Lines. 相似文献
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Arthur Komar 《General Relativity and Gravitation》1995,27(11):1185-1206
A measurement theory for the temperature of relativistic systems is developed. The resulting operational approach is shown to be quasi-local and therefore may be applicable in general Riemannian manifolds even when there are temperature gradients which induce heat flows. The surprising feature of our analysis is that it leads to a bifurcation of the temperature concept into two distinctly different measurable quantities: one a frame invariant scalar field which a local co-moving observer would tend to identify with the local temperature and employ in the definition of entropy, the other a frame dependent, but nevertheless locally determinable quantity which governs the flow of heat and the ability to extract work. The two quantities differ by the bookkeeping methodology employed to calibrate the thermometer. A simple relationship between the two temperatures can be established if a preferred Killing vector field is available in the Riemannian manifold. 相似文献
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A. H. Cai X. Xiong Y. Liu H. Chen W. K. An X. S. Li Y. Zhou Y. Luo 《The European Physical Journal B - Condensed Matter and Complex Systems》2008,64(2):147-151
We propose expressions for the estimation of the isenthalpic temperature T
0 (T
0 = αT
m
, α is a semi-empirical parameter and 0 ⩽ α < 1, T
m
is the solidus temperature) and the Kauzmann temperature T
k
(T
k
= T
m
exp(α−1)) for glass forming alloys. It is found that T
k
estimated by T
k
= T
m
exp(α−1) is in agreement with that directly calculated from the heat capacity data, indicating that T
k
= T
m
exp(α − 1) can be used to estimate T
k
of glass forming alloys. T
0 estimated by T
0 = αT
m
, on the other hand, widely deviates from that of directly calculated from the heat capacity data. This suggests that the
enthalpy difference of the under-cooled liquid and the crystal might be a nonlinear function of the temperature below T
k
. Moreover, the Gibbs free energy difference ΔG is not sensitive to the deviation of α. 相似文献
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Non-equilibrium carrier distributions were obtained in CdS at various temperatures from 77 to 400K. A study is made of the influence of the lattice temperature on the carrier temperature. It is found that the higher the lattice temperature the lower is the difference between carrier and lattice temperatures, though carriers are always thermalized among themselves. The results can be accounted for by carrier relaxation through optical polar phonon emission. 相似文献
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《Physica A》2005,358(1):49-57
The expressions for the nonequilibrium temperature derived from the fluctuation–dissipation theorem and from the differential of the informational nonequilibrium entropy for ideal gases under shear flow are compared. Both temperatures are different, in particular, the thermodynamic temperature derived from the entropy is lower than the local-equilibrium temperature, whereas the effective temperature defined from the fluctuation–dissipation expression is higher than the local-equilibrium temperature. 相似文献
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Ying Lu Zuying Zhang Wei Guo 《International Journal of Infrared and Millimeter Waves》1996,17(9):1567-1571
Based on the transmission-line theory, this paper describes a new procedure to calculate the radiation from layered media with nonuniform temperature profile. The result is compared with those obtained through the incoherent method and the analysis of the electromagnetic fields. 相似文献
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The transit times of ultrasonic waves have been measured in single crystal NbO2 from 295 K down to 1.5 K for quasilongitudinal and shear waves propagating in the [100] direction and down to 160 K for eight other waves. Values are obtained for the C44 elastic constant and for an elastic constant combination which is approximately equal to C11 for temperatures down to 1.5 K and for C11, C12, C13, C16, C33, and C66 down to 160 K. These results are used to deduce 0 K values for the elastic constants and an elastic Debye temperature of 596 ± 7 K at 1.5 K. The acoustic mode heat capacity calculated from the latter is significantly smaller than the heat capacity measured by Wenger and Keesom at low temperatures. Following Wenger and Keesom, the difference is attributed to phasons (excitations involving the phase modulation of charge density waves). An average velocity is deduced for the phasons. 相似文献