Temperature dependence of capacitance on DNA solutions

We have measured the temperature dependence of the capacitance on the poly(dA), poly(dA)–poly(dT), and DNA solutions with both A–T and G–C base pairs to investigate the relation between the capacitance and the DNA structure. As the temperature increases, the capacitance of the single-stranded DNA solution increases, whereas that of the double-stranded one decreases with increasing the temperature and exhibits an upturn when DNA molecules are denatured. Moreover, the temperature dependence of the capacitance is found to be different depending on the DNA sequence. These results suggest that the conformational change of DNA molecules can be detected through the capacitance measurements that do not require any labeling and immobilization on a solid support.     

Temperature dependence of the diffusion coefficients of gases

The use of empirical power laws to calculate the diffusion coefficients of gases is considered. The method of similitude is used to obtain generalized relations which permit the calculation of the diffusion coefficients of gases in temperature ranges not covered by experiment.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 17, No. 3, pp. 530–534, September, 1969.     

Temperature coefficients of the electroelastic constants of quartz

In the domain between -40 degrees and 60 degrees C the temperature derivatives of the electroelastic constants of alpha-quartz are on the order of 10(-3) to 10(-4) N/(V-m- degrees C). This is about 100 times less than hitherto believed. The temperature coefficients T(e(ijk)) given in degrees C(-1 ) are on the same order of magnitude. Also contrary to earlier beliefs, available data cannot be used to determine all eight fundamental independent temperature coefficients T(e (ijk)) existing in the basic reference frame of quartz. Only six relevant quantities can be calculated, five of them as linear combinations of the fundamental T(e(ijk)). Their estimates, based on the available data, are given for 25 degrees C.     

On the calculation of the temperature field in solids with variable heat-transfer coefficients

A method is presented for the approximate determination of the temperature field in solids with variable heat-transfer coefficients.     

Temperature dependence of the transport coefficients of monatomic gases

We study the range of applicability of the power-function approximation for the temperature dependence of viscosity and thermal conductivity of monatomic gases.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 52, No. 4, pp. 642–649, April, 1987.     

Temperature dependence of the transfer coefficients of liquid homologs and their mixtures

A generalized method is proposed for the calculation of the thermal conductivity and viscosity of liquid hydrocarbons and their mixtures belonging to the same homologous series;its use requires no initial information other than the molecular mass.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 58, No. 3, pp. 456–461, March, 1990.     

电容传感器新型电容测量电路设计

提出了一种基于V／T变换的用于电容传感器的电容测量电路。它将被测微小电容变化量转换成时间信号并由单片机进行处理，电路结构简单，电路中没有影响测量稳定性和产生零点漂移的元器件，大幅度地降低了测量过程中的噪声。     

Two capacitance dilatometers

Two different dilatometric devices designed for magneto-strictive strain measurements at low temperatures are described. Their sensitivity is of the order of 10^?10 for relative length changes. They are provided with an adjustable gap system which makes it possible to change the gap between the capacitor plates at helium temperature.     

Temperature dependence of the mutual diffusion coefficients in aqueous solutions of alkali metal chlorides

Measurements of mutual diffusion coefficients at infinite dilution in aqueous solutions of alkali-metal chlorides have been made with the Taylor dispersion technique. Data were obtained for the series LiCl/H₂O, NaCl/H₂O, KCl/H₂O, RbCl/H₂O, and CsCl/H₂O, at five temperatures between 298.15 and 318.15 K. A linear dependence with temperature was found. This technique is very convenient in comparison with other more time-consuming techniques.     

Pulse-fed capacitance measuring circuit

Translated from Izmeritel'naya Tekhnika, No. 11, pp. 55–56, November, 1990.     

Temperature coefficients of SAW delay and velocity for Y-cut and rotated LiNbO(3)

Measurements that indicate that the surface-acoustic-wave (SAW) temperature coefficients of delay and velocity over approximately room temperature to +100 degrees C for the popular cuts of lithium niobate are presented. These values of delay coefficient are close to the value previously given for Y-cut LiNbO(3) but are significantly different from values given for the rotated cuts.     

Oscillation of capacitance inside nanopores

Porous carbons of high surface area are promising as cost-effective electrode materials for supercapacitors. Although great attention has been given to the anomalous increase of the capacitance as the pore size approaches the ionic dimensions, there remains a lack of full comprehension of the size dependence of the capacitance in nanopores. Here we predict from a classical density functional theory that the capacitance of an ionic-liquid electrolyte inside a nanopore oscillates with a decaying envelope as the pore size increases. The oscillatory behavior can be attributed to the interference of the overlapping electric double layers (EDLs); namely, the maxima in capacitance appear when superposition of the two EDLs is most constructive. The theoretical prediction agrees well with the experiment when the pore size is less than twice the ionic diameter. Confirmation of the entire oscillatory spectrum invites future experiments with a precise control of the pore size from micro- to mesoscales.     

Temperature patterns in soils with variable thermophysical coefficients with given temperature conditions in greenhouses

An analytic method is proposed for solving nonstationary heat conduction with transport coefficients dependent on the coordinates. The temperature distributions in soils have been examined for harmonic and exponential laws of variation for the air temperature in greenhouses.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 42, No. 2, pp. 313–320, February, 1982.