ZnO压敏陶瓷导电机理的发展与掺杂氧化物的作用

近20年来，有关ZnO压敏陶瓷研究方面的报道很多，本文从ZnO压敏陶瓷的导电机理及掺杂氧化物的作用方面进行了综合评述。

聚吡咯导电机织物的制备及电阻性能表征

采用化学聚合法制备聚吡咯导电织物，研究了其电阻的环境稳定性以及耐洗涤性能。测试结果表明，聚吡咯导电织物的电阻会随着暴露在环境中的时间延长而增加，洗涤4h并没有造成聚吡咯颗粒明显脱落，但洗涤溶剂与聚吡咯的脱掺杂反应会造成织物电阻的增加。

Formation of mesophase microbeads from bulk mesophase pitch induced by fullerene

A transformation of naphthalene-based coalescenced mesophase pitch(NMP)to mesophase microbeads was achieved by heating a mixture of NMP and fullerene(C_(60)).This is different from the conventional process of the liquid-phase carbonization of isotropic pitch to the emergence of carbon microbeads in the matrix and finally their growth to form a 100%anisotropic bulk meso-phase,but rather a reverse transformation.The effects of C_(60) loading and reaction temperature on the morphological transformation of mesophase were investigated by polarizing optical and scanning electron microscopies.The physical changes in the NMP induced by C_(60) were characterized by thermogravimetric analysis,Fourier transform infrared spectroscopy,X-ray diffractometry and Raman spectroscopy.The results show that the coalesced NMP can be converted to a spherical type at 300-320℃ with the addition of 5%C_(60),and the size of the mesophase microbeads increases with increasing temperature.Furthermore,a model is established to ex-plain the unique induction effect of C_(60) in the transformation process.This work makes the morphological transformation of MP con-trollable,and provides a new idea for the understanding and research of mesophase pitch.

Ba_(0.5)Sr_(0.5)TiO_3湿敏材料的直流特性分析

本研究工作测量了Ba_(0.5)Sr_(0.5)TiO_3湿敏陶瓷在直流电场下的电流-时间特性,用等效电路模型进行了分析,并用指数函数对实验曲线进行了拟合,计算了不同湿度下离子电导、电子电导的绝对量和相对量.结果表明,随着相对湿度的增加,离子和电子电导的绝对量均增大,而电子电导所占的比例下降.文中还对材料的导电机制进行了简单的分析讨论.

Ridge Waveguide Electro-Optic Polymer Modulator with a New Kind of Corona Poled Crosslinkable Polyurethane

A polymer electro optic modulator has been fabricated with the functional layer acting as a kind of corona poled crosslinkable polyurethane. The three optical layers, namely waveguide, photolithography and oxygen are fabricated by spin coating. With the Reactive Ion Etching method, the ridge of the waveguide is constructed. With light at 1 31μm being fiber coupled to waveguide, the mode and the modulation properties of these devices are demonstrated in a micron control system.

SYNTHESIS AND PHOTOELECTRIC PROPERTIES OF PERYLENE RED PIGMENTS

A series of N, N′ dialkyl (and aryl) perylene 3,4:9, 10 bis (dicarboximide) compounds were prepared and purified, and their photoelectric properties as organic photoconductors were explored. It is found that N, N′ dimethyl perylene 3,4:9, 10 bis (dicarboximide) and perylene 3,4:9,10 tetracarboxylic acid bisbenzimidazole show excellent photoconductivities, their charge acceptance reaches 700 V and 485 V, and the photosensitivity is 45 lx·s and 10 lx·s with dark decays 70 and 60 V/s respectively. The introduction of chlorine atoms can improve their photoelectric properties. SEM analyses also show that the dispersion of pigment in OPC could affect its photosensitivity.

Study of the Conductance Characteristic of Doped Polymer by Monte Carlo Method

The conduct mechanism of the doped polymer is considered. In an asymmetrysystem composed of high polymer and doping conductive matte, chain or congeries framework will beformed between the conductive particles to improve the conductance characteristic. In thisprocession, the conductive particles interact to each other. In this paper, we describe theconductance of the doped polymer by Monte Carlo method. The results accord with the experimentsquite well. It can be concluded that there is an evident change of doped polymer from nonconductorto metal.

Mach-Zehnder Electro-Optic Polymer Modulator with C orona Poled Core Layer

A Mach-Zehnder(MZ) electro-optic(EO) modulator are real iz ed,with three optical layers as polymer materials.The functional layer is the co rona poled crosslinkable polyurethane.The ridge waveguide is fabricated by using the spin-coating,poling,photolithography and oxygen reactive ion etching(RIE) techniques.The mode and the modulation properties of these devices are demonstra ted in a micron control system,while the light source works at the wavelength of 1 31 or 1 55 micron.

Heat Resisting Mechanism of Heat-Resisting Aluminum Alloy Conductor and Its Application in Transmission Line

In this paper the heat withstanding mechanism of heat-resisting aluminum alloy conductor is discussed, the types and performance of the conductor and its application on transmission lines are analyzed and introduced, and suggestions on accelerating exploitation and application of the conductor are put forward.

Adaptive rotor current control for wind-turbine driven DFIG using resonant controllers in a rotor rotating reference frame

This paper proposes an adaptive rotor current controller for doubly-fed induction generator (DFIG), which consists of a proportional (P) controller and two harmonic resonant (R) controllers implemented in the rotor rotating reference frame. The two resonant controllers are tuned at slip frequencies ωslip+ and ωslip-, respectively. As a result, the positive- and negative-sequence components of the rotor current are fully regulated by the PR controller without involving the positive- and negative-sequence decomposition, which in effect improves the fault ride-through (FRT) capability of the DFIG-based wind power generation system during the period of large transient grid voltage unbalance. Correctness of the theoretical analysis and feasibility of the proposed unbalanced control scheme are validated by simulation on a 1.5-MW DFIG wind power generation system.

Modelling of modern automotive petrol engine performance using Support Vector Machines

Modern automotive petrol engine performance is significantly affected by effective tune-up. Current practice of engine tune-up relies on the experience of the automotive engineer, and tune-up is usually done by trial-and-error method and then the vehicle engine is run on the dynamometer to show the actual engine performance. Obviously the current practice involves a large amount of time and money, and then may even fail to tune up the engine optimally because a formal performance model of the engine has not been determined yet. With an emerging technique, Support Vector Machines (SVM), the approximate per- formance model of a petrol vehicle engine can be determined by training the sample engine performance data acquired from the dynamometer. The number of dynamometer tests for an engine tune-up can therefore be reduced because the estimated engine performance model can replace the dynamometer tests to a certain extent. In this paper, the construction, validation and accuracy of the model are discussed. The study showed that the predicted results agree well with the actual test results. To illustrate the significance of the SVM methodology, the results were also compared with that regressed using multilayer feedforward neural networks.

Measurements of Conductivity for Low Concentration Strong-electrolytes in Organic Solvents (Ⅰ) LiBr, LiCl, and LiNO_3 in Alcohols

The conductivities of LiBr, LiCl, and LiNO 3 in methanol, ethanol, 1-propanol, and 2-propanol (with electrolyte concentrations <0.08 mol·L-1 ) were determined at 298.15 K, 313.15 K, and 323.15 K at atmosphere pressure separately by using a conductivity meter. The conductivity data were correlated with Foss-Chen-Justice (FCJ) equation and the limiting molar conductivities were obtained. The mean ionic activity coefficients of the salts in the organic solvents were calculated according to the Debye-Hückel limiting law and Onsager-Falkenhangen equations. The calculated results were compared with those activity coefficients in literature.

Analysis and Study on Physicochemical Properties Variation in Fermentation Process of Rapeseed Meal Composting

[Objective] This study aimed to screen out the methods and indices that could quickly and accurately detect the maturity of materials through evaluating the mature status of rapeseed meal composting. [Method] The physicochemical proper- ties variation of rapeseed meal composting was analyzed by testing emission of carbon dioxide, degradation of organic matter, conductivity values, coefficient of seed germination and free amino acids during the fermentation process. [Result] In the process of fermentation, the release amount of carbon dioxide per unit time was drastically reduced at the beginning and then the change became smoothly later. The organic matter was degraded quickly and then slowed down, and the total amount of degradation was 7.34%, total degradation rated of 9.06%. The seed ger- mination coefficient showed a trend of gradual decline, and after the start of fermen- tation, the germination coefficient was below the critical coefficient of 0.8. The con- ductivity value and the free amino acid content changed significantly, which showed strong regularity, and the increase amount was close to 1 times. [Conclusion] The detection of conductivity value and free amino acid content in rapeseed meal com- posting can be used as the methods and indices for the quick and accurate detec- tion of the maturity of organic fertilizer fermentation.

Conduction mechanism studies on electron transfer of disordered system

Using the negative eigenvalue theory and the infinite order perturbation theory, a new method was developed to solve the eigenvectors of disordered systems. The result shows that eigenvectors change from the extended state to the localized state with the increase of the site points and the disordered degree of the system. When electric field is exerted, the electrons transfer from one localized state to another one. The conductivity is induced by the electron transfer. The authors derive the formula of electron conductivity and find the electron hops between localized states whose energies are close to each other, whereas localized positions differ from each other greatly. At low temperature the disordered system has the character of the negative differential dependence of resistivity and temperature.

Preparation and operation characteristics of organic semiconductor transistor using thin film Al gate and copper phthalocyanine

The organic static induction transistors (OSITs) are fabricated by the method of evaporating and plating in a vacuum with copper phthalocyanine (CuPc) dye, and has a five layered structure of Au/CuPc/Al/CuPc/Au. The experiment reveals that OSITs have obtained a low driving voltage, high current density and high switch speed such as I_ DS = 1.2×10 -6 A/mm2, and the degree of 1 000 Hz. The OSITs have excellent operation characteristics of typical static induction transistors.

Crack initiation rate of brittle rock under thermal-hydro-mechanical coupling condition

A calculation formula of thermal-hydro-mechanical(THM)coupling crack initiation rate for brittle rock was derived based on the energy conservation law.The self-designed THM coupling fracture test with conductive adhesive electrical measurement method was applied to measuring the THM coupling crack propagation rate of brittle rock continuously.Research results show that both calculation and test results of crack initiation rate increased with increase of the temperature and the hydraulic pressure.They are almost in good agreement,which can prove validity of the calculation formula of THM coupling crack initiation rate.

Atrial electromechanical coupling parameters after transcatheter aortic valve replacement

The article entitled Effect of transcatheter aortic valve replacement on P-wave duration, P-wave dispersion and left atrial size by Dursun, et al. has contributed to our knowledge regarding the positive effects of transcatheter aortic valve replacement （TAVR） procedure on atrial electrical remodeling. In this study, TAVR procedure led to a decrease on P-wave duration and P-wave dinner,inn

Fast-ionic conductor Li_(2.64)(Sc_(0.9)Ti_(0.1))_(2)(PO_(4))_(3) doped PVDF-HFP hybrid gel-electrolyte for lithium ion batteries

With increasing demand on energy density of lithium-ion battery,wide electrochemical window and safety performance are the crucial request for next generation electrolyte.Gel-electrolyte as a pioneer for electrolyte solidization development aims to solve the safety and electrochemical window problems.However,low ionic conductivity and poor physical performance prohibit its further application.Herein,a fast-ionic conductor(Li_(2.64)(Sc_(0.9)Ti_(0.1))_(2)(PO_(4))_(3))(LSTP)was added into poly(vinylidene fluoride-co-hexafluoropropylene)(PVDF-HFP)base gel-electrolyte to enhance mechanical properties and ionic conductivity.Evidences reveal that LSTP was able to weaken interforce between polymer chains,which increased the ionic conductibility and decreased interface resistance during the cycling significantly.The obtained LiFePO_(4)/hybrid gel-electrolyte/Li-metal coin cell exhibited excellent rate capacity(145 mA·h/g at 1C,95 mA·h/g at 3C,28℃)which presented a potential that can be comparable with commercialized liquid electrolyte system.

An Extended Extrinsic Mechanism for Anomalous Hall Effect

The extrinsic mechanism for anomalous Hall effect in ferromagnets is extended to include the contributions both from spin-orbit-dependent impurity scattering and from the spin-orbit coupling induced by external electric fields. The results obtained suggest that, within the framework of the extrinsic mechanisms, the anomalous Hall current in a ferromagnet may also contain a substantial amount of dissipationless contribution independent of impurity scattering. After the contribution from the spin-orbit coupling induced by external electric fields is included, the total anomalous Hall conductivity is about two times larger than that due to soin-orbit dependent impurity scatterings.

Effect of carboxymethyl cellulose on dissolution kinetics of carboxymethyl cellulose-sodium carbonate two-component tablet

Sodium carbonate and carboxymethyl cellulose powders are compressed into two-component tablets with three mass ratios,97%:3%,95%:5% and 93%:7%.The dissolution tests for two-component tablets and reference pure sodium carbonate tablets are carried out at various temperatures.The dissolution process of each tablet is measured by electrical conductivity tracking method and the concentration of dissolved sodium carbonate is quanti fied with calibrated conductivity-concentration converting equation of sodium carbonate.The quanti fied dissolution data is fitted with both surface reaction model and diffusion layer model and the results clearly show that surface reaction model is suggested as the appropriate dissolution model for all measured tablets.Therefore,it is determined that carboxymethyl cellulose is a stable element to remain the dissolution mechanism of tablet unchanged.The dissolution rate constant quanti fied with surface reaction model presents that carboxymethyl cellulose-sodium carbonate two-component tablets obtain signi ficant higher dissolution rate constant than pure sodium carbonate tablet and higher proportion of carboxymethyl cellulose leads to apparent higher dissolution rate constant.The results prove for the usage of carboxymethyl cellulose in most practical applications at a relative low-level,the effect of carboxymethyl cellulose is effective and positive for two-component tablet to enhance the dissolution process and improve dissolution rate constant and this effect is speculated coming from its dynamic physical transforming process in water including dilation and conglutination.