旋转物体温度的非接触检测原理

本文讨论了利用交流电桥作感温部件及旋转变压器原理实验对旋转体温度的非接触检测。     

钙钛矿/硅异质结叠层太阳电池:光学模拟的研究进展

近几年,钙钛矿/硅异质结叠层太阳电池发展迅速,效率已经从13.7％提升到29.1％.由于叠层电池器件的制作工艺复杂,而叠层太阳电池中的光学损失对转换效率的影响很大,所以通过光学模拟进而获得高效电池至关重要.本文首先从商业软件和自建模型两方面概述了光学模拟的方法,接着从反射损失和寄生吸收两方面针对光学模拟研究进展进行了总...     

Voltammetric Determination of Allura Red AC onto Carbone-paste Electrode Modified by Silica with Embedded Cetylpyridinium Chloride

In current study the carbon-paste electrode modified by silica with embedded cetylpyridinium chloride for determination of Allura Red AC have been developed. The optimal conditions were determined to be for the square-wave voltammetric quantification: pH=2, E_ads=300 mV, t_ads=300 s, amplitude – 40 mV, frequency – 25 Hz and potential scan rate is 250 mV sec⁻¹. The calibration plot has linearity in the concentration ranges 0.04–0.2 μM and 0.2–1.00 μM. The LOD and LOQ are equal to 0.005 μM and 0.015 μM respectively. The crafted sensor has been applied successfully to model solutions and in jelly candies analysis with RSD no more than 10 %.     

Frequency and voltage-dependent electrical and dielectric properties of Al/Co-doped PVA/p-Si structures at room temperature

In order to investigate of cobalt-doped interracial polyvinyl alcohol （PVA） layer and interface trap （Dit） effects, A1/p- Si Schottky barrier diodes （SBDs） are fabricated, and their electrical and dielectric properties are investigated at room temperature. The forward and reverse admittance measurements are carded out in the frequency and voltage ranges of 30 kHz-300 kHz and -5 V-6 V, respectively. C-V or er-V plots exhibit two distinct peaks corresponding to inversion and accumulation regions. The first peak is attributed to the existence of Dit, the other to the series resistance （Rs）, and interfacial layer. Both the real and imaginary parts of dielectric constant （er and err） and electric modulus （Mr and Mrr）, loss tangent （tan~）, and AC electrical conductivity （aac） are investigated, each as a function of frequency and applied bias voltage. Each of the M~ versus V and Mrr versus V plots shows a peak and the magnitude of peak increases with the increasing of frequency. Especially due to the Dit and interfacial PVA layer, both capacitance （C） and conductance （G/w） values are strongly affected, which consequently contributes to deviation from both the electrical and dielectric properties of A1/Co-doped PVA/p-Si （MPS） type SBD. In addition, the voltage-dependent profile of Dit is obtained from the low-high frequency capacitance （CLF-CHF） method.     

Alternating-current losses in two-layer superconducting cables consisting of second-generation superconductors coated by U-shaped ferromagnetic materials

Alternating-current losses in a two-layer superconducting cable, each layer being composed of 15 closely-spaced rectangular wires made up of second-generation superconductors when the ends of wires are coated by either a non-magnetic or strong ferromagnetic material having a U profile is numerically investigated. Computations are carried out through the finite-element method. The alternating-current losses do not increase significantly if the relative permeability of the coating is increased three orders of magnitude, provided that the current amplitude is less than half of the critical current in a superconducting wire. However, the losses are much higher for ferromagnetic coating if the amplitude of the applied current oscillating at 50 Hz is close to the critical current. The ferromagnetic coating is seen to accumulate the magnetic field lines normally on its surfaces, while the field lines are parallel to the long axes of the wires, leading to more significant flux penetration in the coated regions. This facilitates a uniform low-loss current flow in the uncoated regions of the wires. In contrast, coating with a non-magnetic material gives rise to a considerably smaller current flow in the uncoated regions, whereas the low-loss flow is maintained in the coated regions. Moreover, the current flows in opposite directions in the coated and uncoated regions, where the direction in each region is converse for the two materials.     

Induced Electronic and Thermal Effects of 86 MeV Nickel Ions in Bisphenol-A Polycarbonate

Bisphenol-A polycarbonate films were irradiated with 86 MeV swift heavy nickel ions at varying fluences, ranging from 1 × 10¹¹ to 1 × 10¹³ ions cm^?2, under vacuum at room temperature, to analyze the induced electrical and thermal modifications. AC conductivity measurements and UV-visible spectroscopy, Fourier transform infra-red (FTIR) spectroscopy, thermo-gravimetric analysis (TGA), differential scanning calorimetry (DSC), and X-ray diffraction (XRD) techniques were applied to analyze the changes. A significant, exponential increase in conductivity at higher frequency was observed with the increase of nickel ion fluence. UV-visible analysis corroborated the results of the AC conductivity measurement, revealing the increase in size of the carbon clusters embedded in the polymer network, with the increase of heavy ion fluence. FTIR analysis revealed the formation of alkene and alkyne end groups at higher doses, which further supported the suggestion that the variation in electrical properties induced by the ion irradiation of the polymer was due to development of a carbonaceous phase inside the polymer due to the irradiation. Thermal analysis, i.e., TGA and DSC patterns, showed that chain-scission was the leading phenomena in the heavy ion-irradiated polycarbonate samples, resulting in degradation of their thermal stability.     

Promotion effect of adsorbed water/OH on the catalytic performance of Ag/activated carbon catalysts for CO preferential oxidation in excess H2

Activated carbon (AC) supported silver catalysts were prepared by incipient wetness impregnation method and their catalytic performance for CO preferential oxidation (PROX) in excess H₂ was evaluated. Ag/AC catalysts, after reduction in H₂ at low temperatures (≤200 °C) following heat treatment in He at 200 °C (He200H200), exhibited the best catalytic properties. Temperature-programmed desorption (TPD), X-ray diffraction (XRD) and temperature-programmed reduction (TPR) results indicated that silver oxides were produced during heat treatment in He at 200 °C which were reduced to metal silver nanoparticles in H₂ at low temperatures (≤200 °C), simultaneously generating the adsorbed water/OH. CO conversion was enhanced 40% after water treatment following heat treatment in He at 600 °C. These results imply that the metal silver nanoparticles are the active species and the adsorbed water/OH has noticeable promotion effects on CO oxidation. However, the promotion effect is still limited compared to gold catalysts under the similar conditions, which may be the reason of low selectivity to CO oxidation in PROX over silver catalysts. The reported Ag/AC-S-He catalyst after He200H₂00 treatment displayed similar PROX of CO reaction properties to Ag/SiO₂. This means that Ag/AC catalyst is also an efficient low-temperature CO oxidation catalyst.     

Dielectric properties and study of AC electrical conduction mechanisms by non-overlapping small polaron tunneling model in Bis(4-acetylanilinium) tetrachlorocuprate(II) compound

In the present work, the synthesis and characterization of the Bis(4-acetylanilinium) tetrachlorocuprate(II) compound are presented. The structure of this compound is analyzed by X-ray diffraction which confirms the formation of single phase and is in good agreement the literature. Indeed, the Thermo gravimetric Analysis (TGA) shows that the decomposition of the compound is observed in the range of 420–520 K. However, the differential thermal analysis (DTA) indicates the presence of a phase transition at T=363 k. Furthermore, the dielectric properties and AC conductivity were studied over a temperature range (338–413 K) and frequency range (200 Hz–5 MHz) using complex impedance spectroscopy. Dielectric measurements confirmed such thermal analyses by exhibiting the presence of an anomaly in the temperature range of 358–373 K. The complex impedance plots are analyzed by an electrical equivalent circuit consisting of resistance, constant phase element (CPE) and capacitance. The activation energy values of two distinct regions are obtained from log σT vs 1000/T plot and are found to be E=1.27 eV (T<363 K) and E=1.09 eV (363 K<T).The frequency dependence of ac conductivity, σ_ac, has been analyzed by Jonscher's universal power law σ(ω)=σ_dc+Aω^s. The value of s is to be temperature-dependent, which has a tendency to increase with temperature and the non-overlapping small polaron tunneling (NSPT) model is the most applicable conduction mechanism in the title compound.     

动态法测量材料的磁电效应

根据动态法测量磁电效应的基本原理,优化设计并建立了磁电效应测量系统,对其中的一些重要参数对磁电效应测量的影响进行了研究.结果表明,综合考虑测量需要,选择适当的测量参数,对于磁电效应的正确测量十分重要.适当增加线圈长度、减小线圈匝数以及减小交变磁场场强,都是提高磁电效应测量精度、减小测量误差的有效途径.     

超细颗粒在交变电场中团聚过程的数值模拟

建立了异极性荷电颗粒在交变电场中的团聚系数模型,将其应用到Sectional算法中,模拟电场团聚作用对超细颗粒的脱除效果.比较模拟结果与文献中实验数据后发现,在初始浓度不太高时,模拟结果能较好地与实验结果相吻合,而在初始浓度很高时,两者有较大的差异.文中对造成上述现象的可能原因进行了分析.