一种实用的恒温控制电路

介绍一种使用方便的恒温控制电路,绘出其原理图并给出元件清单及安装调试方法     

一种气压传感器新型标定补偿方法（英文）

通常气压传感器的标定补偿方法复杂耗时,开发了一种新的方法去简化气压传感器的标定补偿。首先,设计恒温结构,并通过PID算法自动调节,使气压传感器的核心敏感元件工作于某一个固定温度(此温度稍高于气压传感器需要工作的最高温度点);其次,把气压传感器在与这个固定温度点相等的环境温度下进行标定;最后,完成标定后不管环境温度如何变化,气压传感器敏感元件始终工作在一个恒定的温度,因此气压传感器的标定与补偿可以得到简化。经测试,气压传感器在一定的环境温度范围内实现恒温工作,标定后可以以较高的精度测量气压,实验结果表明经过标定补偿后的气压传感器可以在实际中应用。     

超导直线增能器低温恒温柜的研制

文中详细介绍了超导直线增能器用低温恒温柜的研制过程.采用液氮冷屏保护,液氦作冷源,冷却四只QWR超导腔;静态热损耗小于10W,高频功率负载条件下总热损耗小于50W.该装置还具有机械调谐和功率调谐功能,设备的测量、控制和数据采集采用壹套PLC和工控机来完成,设备的自动化程度和可靠性较高.     

一种气压传感器新型标定补偿方法（英）

通常气压传感器的标定补偿方法复杂耗时,开发了一种新的方法去简化气压传感器的标定补偿。首先,设计恒温结构,并通过PID算法自动调节,使气压传感器的核心敏感元件工作于某一个固定温度（此温度稍高于气压传感器需要工作的最高温度点）;其次,把气压传感器在与这个固定温度点相等的环境温度下进行标定;最后,完成标定后不管环境温度如何变化,气压传感器敏感元件始终工作在一个恒定的温度,因此气压传感器的标定与补偿可以得到简化。经测试,气压传感器在一定的环境温度范围内实现恒温工作,标定后可以以较高的精度测量气压,实验结果表明经过标定补偿后的气压传感器可以在实际中应用。     

一种气压传感器新型标定补偿方法（英）

通常气压传感器的标定补偿方法复杂耗时,开发了一种新的方法去简化气压传感器的标定补偿。首先,设计恒温结构,并通过PID算法自动调节,使气压传感器的核心敏感元件工作于某一个固定温度（此温度稍高于气压传感器需要工作的最高温度点）;其次,把气压传感器在与这个固定温度点相等的环境温度下进行标定;最后,完成标定后不管环境温度如何变化,气压传感器敏感元件始终工作在一个恒定的温度,因此气压传感器的标定与补偿可以得到简化。经测试,气压传感器在一定的环境温度范围内实现恒温工作,标定后可以以较高的精度测量气压,实验结果表明经过标定补偿后的气压传感器可以在实际中应用。     

HB型恒温补偿微压计

本发明提供了一种测定气体微小压力的新型高精度微压计——HB型恒温补偿微压计. 随着科技和生产的迅速发展,人们对测定空气微小压力仪器(尤其是微压计)的要求越来越高.而仪器的高精度和可靠程度则是最突出的问题.据国外有影响的杂志报道,目前也许是因为可以应用计算机和先进电子元件的原因,世界各国大都采用无液气压表进行空气压力测量.但此种气压表毕竟是十分昂贵和娇脆,使用前后通常射均需要大量的时间进行校准.不少类型的压力表在获得最后结果前,还需要进行十分麻烦的计算.此外,这类仪器的最大缺点是,在实际应用中数据离散程度大,不能以…     

夫兰克—赫兹实验中一种新的控温方式

本介绍了一种电路简单、精度高的恒温控制电路。     

恒温恒湿空调三种工况下自动控制研究

针对恒温恒湿空调在夏季、冬季和过渡季节三种典型工况下的自动控制,详细分析了三种工况下空气处理过程,对温度和湿度的控制进行了分解、给出了实现框图并分析了控制系统本身造成的控制精度问题,为恒温恒湿空调的控制改进提供参考。     

在C_(70)固体p-GaAs结构中的甚深深能级

发展了恒温电容瞬态数据处理方法 ,称新方法为恒温电容瞬态时间积谱 (ICTTS) .用ICTTS方法测量分析了C70固体 p GaAs异质结的深能级 ,结果发现在C70 固体中存在两个很深的空穴陷阱 ,H1 和H2 ,它们的能级位置分别为Ev 0 85 6eV和Ev 1 0 37eV     

在LPE生长中降温和恒温对InAsPSb外延层组分分布的影响

采用LPE技术,生长出InAsPSb外延层,研究了降温、恒温两种方法对外延层组分分布的影响。结果表明,用恒温方法生长时,外延层中P、Sb组分分布较为均匀,在脉冲电流激发下,得到了3.09μm激光输出。     

Linear temperature dependence of low temperature pyroelectric coefficient

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.     

Relativistic temperature

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.     

Estimation of Kauzmann temperature and isenthalpic temperature of metallic glasses

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.     

Dependence of hot carriers temperature on lattice temperature in CdS

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.     

Nonequilibrium temperature and fluctuation–dissipation temperature in flowing gases

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.     

Brightness temperature emitted by layered media with nonuniform temperature profile

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.     

Low temperature elastic constants and Debye temperature of NbO2

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.