纯金属电阻率的统计模型

本文提出了纯金属电阻率与声子浓度及声子平均动量的平方成正比的统计模型，由此简化模型，给出了纯金属电阻率的一个解析表达式，理论与实验规律相符，即在高温时，电阻率与温度Ｔ成正比，低温时与Ｔ＾５成正比。     

高灵敏度瞬态辐射高温计

 新研制了一台瞬态辐射高温计。它在设计上做了以下改进，采用：（1）双向色性分光镜作为分光器件，将各个通道波长的分光率提高到85%以上；（2）低输入阻抗宽频高增益（50 dB）信号放大技术做为高温计的后续电路，大大提高了高温计的探测灵敏度，同时也保证了测量系统的快速响应；（3）光谱辐照度方法做零前标定，使零前标定工作方便和可靠。以氯化钠单晶作为实例，测量了它在36.0~60.0 GPa冲击压力下的热辐射历史，获得了1 500~3 600 K冲击温度范围内的瞬态光谱辐射，高温计的响应时间优于5 ns。     

Cr80-xFe20Mnx(x=10,15,20)合金的低温电阻率和热导率

报道了Cr80-xFe20Mnx(x=10,15,20)合金在10—300K的电阻率和热导率．结果表明样品的电输运性质和热输运性质均与样品的磁状态有关．在SDW反铁磁转变附近,电阻率出现极小．对Neel温度以下电阻率-温度曲线拟合结果表明：取温度相关的能隙函数2△∝√（TN-T）可以很好地描述SDW反铁磁能隙随温度降低而打开的过程．合金在反铁磁转变温度以下表现出与无序样品或者玻璃态样品类似的热导率温度关系,这可能是源于合金中磁性团簇的散射．     

Pyrometer unit for GaAs substrate temperature control in an MBE system

An optical pyrometer designed for precision measurement of the GaAs substrate temperature during MBE growth is considered. The pyrometer can be calibrated against a certain characteristic absolute temperature that is visually determined from a change in the RHEED pattern. This enables one to calculate the absolute temperature of the substrate with regard to its radiant emissivity and minimize the inaccuracy of radiation temperature measurement. The inaccuracy is associated with the deposition of growth products on the pyrometer window.     

Temperature dependence of the electrical resistivity of amorphous Co80−xErxB20 alloys

The temperature dependence of the electrical resistivity of amorphous Co_80−xEr_xB₂₀ alloys with x=0, 3.9, 7.5 and 8.6 prepared by melt spinning in pure argon atmosphere was studied. All amorphous alloys investigated here are found to exhibit a resistivity minimum at low temperature. The electrical resistivity exhibits logarithmic temperature dependence below the temperature of resistivity minimum T_min. In addition, the resistivity shows quadratic temperature behavior in the interval T_min<T<77 K. At high temperature, the electrical resistivity was discussed by the extended Ziman theory. For the whole series of alloys, the composition dependence of the temperature coefficient of electrical resistivity shows a change in structural short range occurring in the composition range 8–9 at%.     

Calculation of electrical resistivity of Mg,Cd, and Zn in solid and liquid state. local pseudopotential approximation

Pseudopotential method, thermodynamic perturbation theory, and the formula due to Ziman are used for calculating the temperature dependence of the electrical resistivity of solid and liquid Mg, Cd, and Zn. In solid metals, a system of Einstein oscillators is chosen as the ground state, and in melts, solid spheres are chosen. Electrical resistivity of a solid metal is represented by a sum of a diffusion and a continuous contribution, with the latter practically completely determining the temperature dependence of electrical resistivity. The local pseudopotential approximation is found to be sufficiently correct for calculating the electrical resistivity of Mg; however, it gives lower values of electrical resistivities of Cd and Zn, which is due to neglecting hybridization effects.Translated from Izvestiya Vysshikh, Uchebnykh Zavedenii, Fizika, No. 3, pp. 93–100, March, 1984.     

Hall-Koeffizient und elektrischer Widerstand flüssiger Al-Ga-Legierungen

The dependence of the Hall coefficient and the electrical resistivity on temperature and concentration has been measured for liquid Al-Ga alloys. The experimental Hall coefficients were found to agree with their respective free-electron values when the assumption is made that liquid Al and Ga provide 3 free electrons per atom. The electrical resistivity versus concentration is approximately a straight line and the temperature coefficient of the electrical resistivity is always positive.     

烧结温度对La0.9Sr0.1FeO3热电性能的影响

利用传统的固相反应分别在1250℃,1300℃,1350℃.烧结条件下制备出钙钛矿结构的La_0.9Sr_0.1FeO₃陶瓷样品.样品的XRD粉末衍射结果显示不同烧结温度的La_0.9Sr_0.1FeO₃陶瓷样品都是单相的正交结构,同时晶胞体积随着烧结温度的升高而减小.从样品的SEM结果看出,随着烧结温度的升高,晶粒逐渐变大,并且晶粒间的空隙逐渐减小,样品更加致密.在室温到800℃的 关键词： 铁酸镧陶瓷 热电性能 烧结温度     

DC electrical resistivity for CoxNi5/3−xSb1/3Fe1O4 ferrites

The DC electrical resistivity (p) was studied for Co substituted SbNi ferrites as a function of temperature and composition. The experimental results showed that DC resistivity, Curie temperature and activation energies for electrical conduction increase as Co-ion substitution decreases. The DC electrical conductivity increases as temperature increases. The real part of dielectric constant (e') was found to be inversely proportional to the root mean square value of the electrical resistivity.     

Measurement performance of an optical CCD-based pyrometer system

The measurement performance of a CCD-based pyrometer system using a three-color method was evaluated for scientific and engineering metrology. The relationships between the system parameters (exposure time and sensor gain) and the intensity measurements in an integrating sphere experiment were determined for a specific CCD sensor. The pyrometer system uses the three-color method based on the intensity ratio without geometry calibrations. The field measurement characteristics and the effectiveness of coupling the three-color channels were investigated in terms of the temperature measurement uniformity, temperature sensitivity and temperature range of the pyrometer system in standard blackbody tests. The results showed that the temperature non-uniformity is not proportional to the intensity non-uniformity and is in the range of 0.13-2.14%. The relative temperature sensitivities of intensity ratios for different channel combinations are different, which may provide a way to improve the measurement results. The temperature range bandwidth for object with a non-uniform temperature distribution varies from 190 to 270 K for this specific CCD-based pyrometer. The performance evaluation conclusions for the system with this specific CCD sensor are general and applicable for pyrometer systems using other CCD sensors.     

用于固体火箭羽焰真温测量的宽量程多光谱高温计

现有的多光谱高温计的测量下限均大于1 173 K(900 ℃),不适用于新型火箭羽焰真温测量范围的要求(900~2 700 K)。为了解决现有的多光谱高温计无法测量1 173 K以下羽焰真温的问题,研制了用于固体火箭发动机羽焰真温测量的宽量程多光谱高温计。该多光谱高温计采用了并联光电探测器阵列相邻像元的方法,并且创建了基于对数函数的900~1 173 K温区的温度标定方法,从而拓宽了高温计的温度测量范围。针对某型号固体火箭发动机羽焰的三个目标点进行了现场测量,实验结果验证了该高温计的有效性。     

Electrical resistivity of metastable copper-iron solid solutions

Metallic solid solutions of CuFe are produced by simultaneous condensation of both components onto a sapphire substrate held at 80 K. The electrical resistivity of the CuFe films is measured as a function of temperature throughout the whole concentration range. Maxima in the residual resistivity appear at 20 at-% and 80 at-% Fe. A low temperature minimum in the electrical resistivity is observed on the Fe rich side of the system.     

Constant electrical resistivity of Zn along the melting boundary up to 5 GPa

We measured the electrical resistivity of high purity Zn along the melting boundary, up to 5?GPa in a large volume press. The electrical resistivity remained constant on the melting boundary, as predicted in a thermodynamics-based model for simple metals. The effects of pressure and temperature on the electrical resistivity of the solid and liquid states are interpreted in terms of their antagonistic effects on the electronic structure of Zn. Within the error of measurements, our melting temperature data agree well with those of the previous studies. The electronic thermal conductivity was calculated from resistivity data using the Wiedemann–Franz law and shows a decrease with temperature in the solid state and an increase in the liquid state, with a large decrease on melting. Comparison of calculated electronic and measured total thermal conductivities indicates that the electronic component dominates over the phonon component in Zn.     

Influence of copper intercalation on the resistive state of compounds in the Cu-HfSe<Subscript>2</Subscript> system

Polycrystalline samples of intercalated compounds Cu _x HfSe₂ have been synthesized for the first time and their electrical resistivity has been measured at both direct current and alternating current (with a frequency ranging from 200 Hz to 150 kHz) in the temperature range 80–300 K. It has been shown that the intercalation of copper atoms between three-layer Se-Hf-Se blocks leads to an increase in the electrical resistivity of the samples, as well as to a more pronounced activated character of the temperature dependence of the electrical resistivity. A time dependence of the electrical resistivity of the Cu _x HfSe₂ samples at room temperature, which is associated with the presence of copper ions in the sample, has been determined.     

Low-temperature electrical resistivity characteristics of fast-neutron-irradiated CdS: New concepts in neutron detection

Time dependent electrical resistivity changes at low temperature in fast-neutron irradiated CdS have been studied. The experiments were on low-resistivity single crystals, and the electrical changes result from radioactive decay effects induced by the fast-neutron irradiation. Results show that following neutron irradiation and upon lowering the sample temperature, the resistivity decreases with time and approaches a stable value. These effects are attributed to trapping phenomena, and can be erased by increasing the temperature. The time dependent electrical changes associated with radioactive decay provide a new means for neutron detection.     

Comment on “variable range hopping in Si:P at very low temperature” surface conduction in Si:P

The electrical resistivity of doped semiconductor Si:P in the intermediate concentration range was measured under various surface conditions. The surface treatments are shown to have a great influence upon the low temperature electrical conduction, and T^-2-like temperature dependence of resistivity is attributed to the surface layer electrical conduction.     

用于真空弧等离子体放电阴极温度场测量的多光谱高温计

阴极表面温度是真空弧等离子体放电过程中一个重要参数,对真空弧等离子体的形成、电极腐蚀预测、热传导以及离子源的寿命都有重要影响。真空弧离子源的阴极具有目标小,放电过程快等特点,其温度的测量,对于时间分辨率和空间分辨率要求都很高,阴极表面温度的测量技术的欠缺,使得仅靠理论解析获得的结果难以得到验证。并且等离子体放电过程中测量仪器极易受到弧光的影响,如何避免放电过程中等离子体的辐射也是采用辐射法测量阴极表面温度要考虑的问题。这无疑给其温度场的测试研究带来困难。针对脉冲真空弧等离子体开展阴极表面温度测试实验有着重要意义,在分析了真空弧等离子体放电特性以及背景辐射特性和等离子体放电阴极测温的实际需求,本文基于高速CCD相机研制了一种新型的多光谱高温计。该高温计采用单色高速CCD相机,主要避免RGB彩色相机不能完全滤除背景辐射的弧光。为使用单色CCD相机实现多光谱辐射测温,设计了高温计的光学系统,该系统采用4孔径分光系统。将4种不同波长的滤光片嵌入到1个滤光片中。该研究设计的高温计可用于2 000~6 000 K的等离子体温度测量。并在中国工程物理研究院电子工程研究所进行现场测试,测试过程中将研制的高温计,通过外部触发形式对等离子体放电过程进行跟踪拍摄,高温计完全拍摄到等离子体放电过程。利用真空弧等离子体金属电极阴极放电的实测数据对高温计进行了验证。实验结果表明,设计的新型多光谱高温计能够用于测量真空弧等离子体放电时阴极温度场信息,测量的温度值低于放电电极的沸点温度,与等离子体放电过程中出现气化现象相符,说明高温计测的是等离子体放电阴极的温度。     

CdSe在高压下的电学性质及相变

 利用在金刚石压砧上集成的微电路,原位测量了CdSe多晶粉末在温度为300~450 K、压力达到23 GPa时电阻率随温度和压力的变化关系。实验结果表明：在加压过程中,电阻率在2.6 GPa压力时出现的异常改变,对应着CdSe从纤锌矿向岩盐矿结构的转变,而在6.0、9.8、17.0 GPa等压力处出现的电阻率异常,则是由CdSe中的电子结构的变化所引起的;在卸压过程中,只在约14.0和3.0 GPa压力下观察到了两个电阻率异常点。通过对电阻率随压力变化曲线的模拟,得出了CdSe高压相的带隙随压力的变化关系,据此预测CdSe金属化的压力应在70~100 GPa之间。变温实验结果表明,在实验的温度和压力范围内,CdSe的电阻率均随温度的增加而升高。     

Effect of magnetic domains on the electrical resistivity of a ferromagnet just below the critical temperature

The motion of magnetic domains has been detected by measurements of the electrical resistivity temperature derivative in the vicinity of the critical temperature of various ferromagnetic systems. The case of TbZn serves as an illustration. A theoretical model is based on a mean field expression for the electrical resistivity.     

InSe的高压电输运性质研究

高压下对InSe样品进行原位电阻率和霍尔效应测量. 电阻率测量结果显示, 样品在5–6 GPa区间呈现金属特性, 在12 GPa 的压力下发生由斜六方体层状结构到立方岩盐矿的结构相变, 且具有金属特性. 霍尔效应测量结果显示, 样品在6.6 GPa由p型半导体转变成n型半导体, 电阻率随着压力的升高而逐渐下降是由于载流子浓度升高引起的. 关键词： InSe 高压 电阻率 霍尔效应