The searching about methods to connect the variables with each other to reach equations including multi variables. The dimensional analysis is a method to facilitate the solution of difficult mathematic equations and ...The searching about methods to connect the variables with each other to reach equations including multi variables. The dimensional analysis is a method to facilitate the solution of difficult mathematic equations and experimental formulas;therefore methods of simplifying the difficult equations and obtaining a new equation with different variables is needed. In this study will use 2 methods (statically with dimensionally analysis) to obtain electric conductivity of water of Euphrates river by multi parameters that are time (t), temperature (Te), density, viscosity, discharge and water depth in upstream of Alhindya barrage which located in Babylon governorate, Iraq during winter 2019. The equations were obtained for EC with Te and t by data were collected from Alhindya barrage office with R<sup>2</sup> = 0.999 and R<sup>2</sup> = 0.995 by statically ways. Dimension analysis was utilized via 2 stages. In first stage was obtained on equation of EC with respect to Te, water density (ρ) and dynamic viscosity (μ) with constant time, depth of water and discharge and we obtain on R<sup>2</sup> was 0.994 and R<sup>2</sup> = 0.986. In second stage was obtained formula of EC with respect to Te, water density (ρ), dynamic viscosity (μ), with variable time, depth of water and discharge with we obtain on R<sup>2</sup> = 0.945 and R<sup>2</sup> = 0.94. The result of research indicates that applying the dimension analysis to connect more than one variable with each other to find best solutions and best methods to facilitate the solving the equations. From dimension analysis gave a clear visualization of the association of several variables to give a result that helps measure the electrical conductivity of water in the absence of a water test device.展开更多
Ce-doped Bi2O3 nanopowders were prepared by reverse titration chemical coprecipitation from Bi^3+and Ce^(4+)containing aqueous solution.Techniques of X-ray diffraction(XRD),transmission electron microscopic(TEM...Ce-doped Bi2O3 nanopowders were prepared by reverse titration chemical coprecipitation from Bi^3+and Ce^(4+)containing aqueous solution.Techniques of X-ray diffraction(XRD),transmission electron microscopic(TEM)and Fourier transform infrared spectroscopy(FTIR)were employed to characterize the as-synthesized materials.The XRD patterns indicated that the peaks can be easily indexed toβ-Bi2O3 and no diffraction peaks of Ce or other impurity phases were detected in the prepared samples.The calculated average crystalline size decreased from 31.72 to 11.96 nm when the Ce content increased from 1 wt%to 10 wt%.The morphology changed from flake-like into the spherical-like with increase in Ce content.The electric conductivity of Ce-doped Bi2O3 electrolyte was also investigated by two probe DC method.Conductivity analysis exhibited that the rate of conductivity increased with increasing Ce^2+ratio,when the Ce concentration was up to 5 wt%,the as-synthesized Ce-doped Bi2O3 electrolyte showed the maximum value of conductivity(0.295 S?cm^(–1)).展开更多
In this paper, instead of with the more expensive Fourier Transform Infrared Spectrometer(FTIR) a new technique of Temperature Programmed Transient Response(TP-TR) has been used with gas chromatography. Therefore, the...In this paper, instead of with the more expensive Fourier Transform Infrared Spectrometer(FTIR) a new technique of Temperature Programmed Transient Response(TP-TR) has been used with gas chromatography. Therefore, the TP-TR will be applied more widespreadly than ever before. With the technique of TP-TR and electric conductivity, the study is on the reaction mechanism and the adsorption behavior of the reactants and products to the present catalyst Mo-V-Nb/Al_2O_3 in the reaction from ethane through oxydehydrogenation to ethylene as the product. By Range-Kutta-Gill and Margarat methods, the kinetic parameters of the reaction elementary steps (i.e. rate constants, active energies and frequency factors) have been evaluated. The mathematical treatment coincides with the experimental results.展开更多
Clays have considerable influence on the electrical properties of hydrate-bearing sediments.It is desirable to understand the electrical properties of hydrate-bearing clayey sediments and to build hydrate saturation(S...Clays have considerable influence on the electrical properties of hydrate-bearing sediments.It is desirable to understand the electrical properties of hydrate-bearing clayey sediments and to build hydrate saturation(S_(h))models for reservoir evaluation and monitoring.The electrical properties of tetrahydrofuran-hydrate-bearing sediments with montmorillonite are characterized by complex conductivity at frequencies from 0.01 Hz to 1 kHz.The effects of clay and Sh on the complex conductivity were analyzed.A decrease and increase in electrical conductance result from the clay-swelling-induced blockage and ion migration in the electrical double layer(EDL),respectively.The quadrature conductivity increases with the clay content up to 10%because of the increased surface site density of counterions in EDL.Both the in-phase conductivity and quadrature conductivity decrease consistently with increasing Sh from 0.50 to 0.90.Three sets of models for Sh evaluation were developed.The model based on the Simandoux equation outperforms Archie’s formula,with a root-mean-square error(E_(RMS))of 1.8%and 3.9%,respectively,highlighting the clay effects on the in-phase conductivity.The fre-quency effect correlations based on in-phase and quadrature conductivities exhibit inferior performance(E_(RMS)=11.6%and 13.2%,re-spectively)due to the challenge of choosing an appropriate pair of frequencies and intrinsic uncertainties from two measurements.The second-order Cole-Cole formula can be used to fit the complex-conductivity spectra.One pair of inverted Cole-Cole parameters,i.e.,characteristic time and chargeability,is employed to predict S_(h) with an E_(RMS) of 5.05%and 9.05%,respectively.展开更多
Graphene(Gr)has unique properties including high electrical conductivity;Thus,graphene/copper(Gr/Cu)composites have attracted increasing attention to replace traditional Cu for electrical applications. However,the pro...Graphene(Gr)has unique properties including high electrical conductivity;Thus,graphene/copper(Gr/Cu)composites have attracted increasing attention to replace traditional Cu for electrical applications. However,the problem of how to control graphene to form desired Gr/Cu composite is not well solved. This paper aims at exploring the best parameters for preparing graphene with different layers on Cu foil by chemical vapor deposition(CVD)method and studying the effects of different layers graphene on Gr/Cu composite’s electrical conductivity. Graphene grown on single-sided and double-sided copper was prepared for Gr/Cu and Gr/Cu/Gr composites. The resultant electrical conductivity of Gr/Cu composites increased with decreasing graphene layers and increasing graphene volume fraction. The Gr/Cu/Gr composite with monolayer graphene owns volume fraction of less than 0.002%,producing the best electrical conductivity up to59.8 ×10^(6)S/m,equivalent to 104.5% IACS and 105.3% pure Cu foil.展开更多
Open-source and free tools are readily available to the public to process data and assist producers in making management decisions related to agricultural landscapes. On-the-go soil sensors are being used as a proxy t...Open-source and free tools are readily available to the public to process data and assist producers in making management decisions related to agricultural landscapes. On-the-go soil sensors are being used as a proxy to develop digital soil maps because of the data they can collect and their ability to cover a large area quickly. Machine learning, a subcomponent of artificial intelligence, makes predictions from data. Intermixing open-source tools, on-the-go sensor technologies, and machine learning may improve Mississippi soil mapping and crop production. This study aimed to evaluate machine learning for mapping apparent soil electrical conductivity (EC<sub>a</sub>) collected with an on-the-go sensor system at two sites (i.e., MF2, MF9) on a research farm in Mississippi. Machine learning tools (support vector machine) incorporated in Smart-Map, an open-source application, were used to evaluate the sites and derive the apparent electrical conductivity maps. Autocorrelation of the shallow (EC<sub>as</sub>) and deep (EC<sub>ad</sub>) readings was statistically significant at both locations (Moran’s I, p 0.001);however, the spatial correlation was greater at MF2. According to the leave-one-out cross-validation results, the best models were developed for EC<sub>as</sub> versus EC<sub>ad</sub>. Spatial patterns were observed for the EC<sub>as</sub> and EC<sub>ad</sub> readings in both fields. The patterns observed for the EC<sub>ad</sub> readings were more distinct than the EC<sub>as</sub> measurements. The research results indicated that machine learning was valuable for deriving apparent electrical conductivity maps in two Mississippi fields. Location and depth played a role in the machine learner’s ability to develop maps.展开更多
Natural soils of various types have different electrical properties due to the composition,structure,water content,and temperature.In order to investigate the electrical properties of lateritic soil,electrical conduct...Natural soils of various types have different electrical properties due to the composition,structure,water content,and temperature.In order to investigate the electrical properties of lateritic soil,electrical conductivity experiments have been conducted on a self-developed testing device.Test results show that the electrical conductivity of laterite increases with the increase of water content,degree of saturation and dry density.When the water content is below the optimum water content,the electrical conductivity of soils increases nonlinearly and the variation rate increases dramatically.However,when the water content,degree of saturation,or dry density increases to a certain value,the electrical conductivity tends to be a constant.In addition,soil electrical conductivity increases with the increase of temperature,and it is observed that the electrical conductivity decreases with the increase of the number of wetting–drying cycles.展开更多
Metal Sm has been widely used in making Al–Sm magnet alloy materials. Conventional distillation technology to produce Sm has the disadvantages of low productivity, high costs, and pollution generation. The objective ...Metal Sm has been widely used in making Al–Sm magnet alloy materials. Conventional distillation technology to produce Sm has the disadvantages of low productivity, high costs, and pollution generation. The objective of this study was to develop a molten salt electrolyte system to produce Al–Sm alloy directly, with focus on the electrical conductivity and optimal operating conditions to minimize the energy consumption. The continuously varying cell constant(CVCC) technique was used to measure the conductivity for the Na3AlF6–AlF3–LiF–MgF2–Al2O3–Sm2O3electrolysis medium in the temperature range from 905 to 1055°C. The temperature(t) and the addition of Al2O3(W(Al2O3)), Sm2O3(W(Sm2O3)), and a combination of Al2O3and Sm2O3into the basic fluoride system were examined with respect to their effects on the conductivity(κ) and activation energy. The experimental results showed that the molten electrolyte conductivity increases with increasing temperature(t) and decreases with the addition of Al2O3or Sm2O3or both. We concluded that the optimal operation conditions for Al–Sm intermediate alloy production in the Na3AlF6–AlF3–LiF–MgF2–Al2O3–Sm2O3system are W(Al2O3) + W(Sm2O3) = 3wt%, W(Al2O3):W(Sm2O3) = 7:3, and a temperature of 965 to 995°C, which results in satisfactory conductivity, low fluoride evaporation losses, and low energy consumption.展开更多
At presure 1.0-4.0 GPa and temperature 1073-1423 K and under oxygen partial pressure conditions, a YJ-3000t multi-anvil solid high-pressure apparatus and Sarltron-1260 Impedance/Gain-Phase analyzer were employed to co...At presure 1.0-4.0 GPa and temperature 1073-1423 K and under oxygen partial pressure conditions, a YJ-3000t multi-anvil solid high-pressure apparatus and Sarltron-1260 Impedance/Gain-Phase analyzer were employed to conduct an in-situ measurement of the electrical conductivity of orthopyroxene. The buffering reagents consist of Ni+NiO, Fe+Fe3O4, Fe+FeO and Mo+MoO2 in order to control the environmental oxygen fugacity. Experimental results made clear that: (1) within the measuring frequency range from 10-1 to 106 Hz, the complex impedance (R) is of intensive dependence on the frequency; (2) The electrical conductivity (a) tends to increase along to the rise of temperature (T), and Log a vs. 1/ T fit the Arrenhius linear relations; (3) Under the control of oxygen buffer Fe+Fe3O4, with the rise of pressure, the activation enthalpy tends to increase whereas the electrical conductivity tends to decrease. The activation energy and activation volume of the main current carders of orthopyroxene have been obtained, which are (1.715±0.035) eV and (0.03±0.01) cm^3/mol, respectively; (4) Under given pressure and temperature, the electrical conductivity tends to increase with increasing oxygen fugacity, while under given pressure the activation enthalpy tends to decrease with increasing oxygen fugacity; and (5) The sample's small polarons mechanism has provided a reasonable explanations to the conduction behavior at high temperature and high pressure.展开更多
The frequency and temperature dependent electrical conductivity measurements for heat-treated binary glass system with composition of (lO0-x)Bi203-xBaTi03 (x = 20, 30, 40 and 50, in mol%) were carried out. The gla...The frequency and temperature dependent electrical conductivity measurements for heat-treated binary glass system with composition of (lO0-x)Bi203-xBaTi03 (x = 20, 30, 40 and 50, in mol%) were carried out. The glass was prepared by melt quenching technique and their corresponding glass-ceramic nanocomposites were obtained by suitable heat treatment. Nanostructured behavior and electrical properties of these glasses and their corresponding glass-ceramic nanocomposites were studied. X-ray diffraction (XRD) and differential scanning calorimetry confirmed the amorphous nature of the glasses. Moreover, XRD patterns of the samples indicate nanocrystallites embedded in the glass matrix. The Fourier transform infrared spectroscopy (FT-IR) spectral analysis showed that the band positions of glass system are within the wave number range of Bi06, Bi03 and Ti06 structural units. It is observed that the electrical conductivity is enhanced by 102-103 times in the transparent glass-ceramic nanocomposite phase. With further heat treatment, the conductivity decreased considerably in the stage of glass-ceramic nanocomposite phase as compared with the glassy phase sample. Therefore, partially devitrified phase is more suitable as cathode material in secondary batteries compared to its vitreous or fully crystalline counterpart. The conduction mechanism was confirmed to obey the adiabatic small polaron hopping (SPH). AC conductivity measurements were performed as a function of temperature and frequency, showing a very slow increasing rate at low temperatures and then a fast rate at higher temperatures.展开更多
BN ceramic is an advanced engineering ceramics with excellent thermal shock resistance, good workability and excellent dielectricity.TiB 2 ceramic has excellent electric conductivity,high melting points, and corrosio...BN ceramic is an advanced engineering ceramics with excellent thermal shock resistance, good workability and excellent dielectricity.TiB 2 ceramic has excellent electric conductivity,high melting points, and corrosion resistance to molten metal.Therefore,the composite consisting of BN and TiB 2 ceramics is expected to have a combination of above mentioned properties,thereby can be used as self heating crucible.In this paper,hot pressing technology was used to fabricate the high performance BN TiB 2 composite materials.microstructure and electric conducting mechanism were studied,and the relationship between the microstructure and physical property was discussed.The results show that the microstructure of composites has a great influence on the physical property of composites.The BN TiB 2 composites with excellent mechanical strength and stable resistivity can be obtained by optimizing the processing parameter and controlling the microstructure of composites.展开更多
Monolayer chemically converted graphene (CCG) nanosheets can be homogeneously self-assembled onto silicon wafer modified by 3-aminopr- opyl triethoxysilane (APTES) to form very thin graphene film. The CCG film was...Monolayer chemically converted graphene (CCG) nanosheets can be homogeneously self-assembled onto silicon wafer modified by 3-aminopr- opyl triethoxysilane (APTES) to form very thin graphene film. The CCG film was characterized by FT-IR, XRD, SEM, TEM and AFM. Results show that CCG sheets formed monolayer film after assembled onto silicon wafer and there is a very tight chemical bond between sheets and wafer. Furthermore, the electrical measurements revealed that the monolayer graphene film has an excellent electrical conductivity.展开更多
In order to assess the effects of chemical properties of soil salinity on electrical conductivity of 1:5 soil/water extract (EC1:5), the study focused on revealing the main chemical factors contributing to EC of s...In order to assess the effects of chemical properties of soil salinity on electrical conductivity of 1:5 soil/water extract (EC1:5), the study focused on revealing the main chemical factors contributing to EC of soil extracts and their relative importance. The relationship between EC1:5 and the chemical properties of soil salinity in the delta oasis of Weigan and Kuqa rivers, China, were studied using path coefficient analysis, a path analysis method. We studied each key element affecting EC1:5 either directly or indirectly. The results obtained show that the salt content, total dissolved solids (TDS), and the sum of the sodium ion concentration and the kalium ion concentration are the most influential factors on 1:5 soil/ water extract (EC1:5) in the 0-10 cm and the 30-50 cm soil layer. The results show that the sequence of direct path coefficients in the 0-10 cm and the 30-50 cm soil layers on soil conductivity is TDS→Na^+ + K^+→Salt content→Ca^2+→Cl-→the sodium dianion ratio (SDR)→pH→ SO4^2-→HCO3^-→Mg^2+→the soluble sodium percentage (SSP) sodium absorption ratio (SAR) and TDS→Salt content→Na^+ + K^+→Ca^2+→SDR→Mg^2+→HCO3^-→SSP→pH→SO4^2-→SAR→Cl^-. The salt content, chlorine ion, and SAR are the main factors affecting 1:5 soil/water extract (EC1:5) in the 10-30 centimeter soil layer. The order of direct path coefficients result is as follows: Salt content→Cl^-→SAR→SSP→TDS→Ca^2+→Mg^2+= SO4^2-→HCO3^-→pH→SDR→Na^- + K^+. Moreover, the effects of HCO3^-, pH were very weak. Though the direct path coefficients between EC1:5 and SAR, SO4^2- and Ca^2+ were not high, influence of other chemical factors caused the coefficients to increase, making the summation of their direct and indirect path coefficients relatively high. The models of the different soil layers were structured separately. Evidences showed that multiple regression relations between EC1:5 and most of the primary factors had sound reliability and very good accuracy. The research results can serve as a reference to the scientific management amelioration and utilization of saline in the Delta Oasis of Weigan and Kuqa rivers.展开更多
The changes of electrical conductivity (resistance) between Sn-3.0Ag-0.5Cu solder joints and printed circuit board (PCB) assembly during aging at 125℃ were investigated by the four-point probe technique. The micr...The changes of electrical conductivity (resistance) between Sn-3.0Ag-0.5Cu solder joints and printed circuit board (PCB) assembly during aging at 125℃ were investigated by the four-point probe technique. The microstructural characterizations of interfacial layers between the solder matrix and the substrate were examined by optical microscopy and scanning electronic microscopy. Different types of specimens were designed to consider several factors. The experimental results indicate that electrical conductivities (resistances) and residual shear strengths of the solder joint specimens significantly decrease after 1000 h during isothermal aging. Microcracks generate in the solder matrix at the first 250 h. Besides, the evolutions of microstructural characterizations at the interface and the matrix of solder joints were noted in this research.展开更多
The effect of heat treatment on electrical conductivity of Cu alloy containing Ni, Al, and rare earth(Ce) alloying elements was studied by metallographic microscope, TEM, SEM/EDS and conductance instrument. The result...The effect of heat treatment on electrical conductivity of Cu alloy containing Ni, Al, and rare earth(Ce) alloying elements was studied by metallographic microscope, TEM, SEM/EDS and conductance instrument. The results indicate that heat treatment can improve the electrical conductivity of the material due to the reducing of the solid solution of Cr element in Cu matrix. The better conductivity was obtained after getting solid solution at 980 ℃ for 1 h, and then aging at 500 ℃ for 4 h.展开更多
Polyaluminium chlorides with sulfate ion(PACS) were prepared by using AlCl 3·6H 2O, Al(SO 4) 3·18H 2O and Na 2CO 3 as raw materials. The effects of basicity ( r ), Al 3+ /SO 4 2- molar r...Polyaluminium chlorides with sulfate ion(PACS) were prepared by using AlCl 3·6H 2O, Al(SO 4) 3·18H 2O and Na 2CO 3 as raw materials. The effects of basicity ( r ), Al 3+ /SO 4 2- molar ratio and aging time on the morphology of PACS were observed by transmission electrical microscope. The influence of aging time on charge neutralization and coagulation effect of PACS was studied. The effects of basicity ( r ), Al 3+ /SO 4 2- molar ratio and aging time on the electrical conductivity of PACS solution were also investigated. The experimental results show that the degree of polymerization of polyaluminium chloride(PAC) increases when SO 4 2- ion is added. The higher the basicity( r ) and the longer the aging time, the larger the size of polymer PACS. The ability of PACS neutralizing the charge on Kaolinite decreases with the increase of aging time. The electrical conductivity of PACS solution(the concentration of Al 3+ ion is 0.18 mol/L) with different aging time is the function of the basicity and Al 3+ /SO 4 2- molar ratios and has its maximum at r =0.5 and Al 3+ /SO 4 2- =12.展开更多
The La0.7Sr0.3CryMnzCo(1-y-z)O3-δ samples were prepared by solid state reaction.The phases,microstructure and properties of the samples were investigated by XRD,SEM,DC four-probe method and iodometry method.The singl...The La0.7Sr0.3CryMnzCo(1-y-z)O3-δ samples were prepared by solid state reaction.The phases,microstructure and properties of the samples were investigated by XRD,SEM,DC four-probe method and iodometry method.The single orthorhombic phase La0.7Sr0.3CryMnzCo(1-y-z)O3-δ perovskite oxides were obtained when sintered at l350 °C for 10 h.The oxygen nonstoichiometry of the materials varied inversely with the total electronic conductivity.The sample with composition of La0.7Sr0.3Cr0.5Mn0.35 Co0.15O3-δ had the maxima...展开更多
The effects of rare earths on electric conductivity fusion welding-resistance and erosion-resistance by electric arc of copper-based compound material by adding different amount of rare earths to copper base to get co...The effects of rare earths on electric conductivity fusion welding-resistance and erosion-resistance by electric arc of copper-based compound material by adding different amount of rare earths to copper base to get copper based compound materials were studied. Rare earths improve active ability among interfaces and optimize organizational structures. The conductivity of samples with rare earths is obviously better than that of materials without them. Moreover, wear ability and oxidization resistance of materials with rare earths can be improved greatly. For copper contact head with rare earths, electric arc corrosion resistance and welding-melting resistance are improved. Such alloys also decrease resistance change with increasing temperature. But the adding quantity of rare earths should be appropriate and formed handicraft should be properly regulated.展开更多
Electrical conductivity of molten slag is an important physicochemical property for designing the refming process in electric smelting furnaces. Though conductivities of many slag systems have been measured, the quant...Electrical conductivity of molten slag is an important physicochemical property for designing the refming process in electric smelting furnaces. Though conductivities of many slag systems have been measured, the quantitative relationships of conductivity with slag composition and temperature are still very limited. In this article, the Arrhenius law was used to describe the experimental data of conductivities for CaO-MgO-Al2O3-SiO2, CaO-Al2O3-SiO2, CaO-MnO-AlEO3-SiO2, as well as CaO-MgO-MnO- Al2O3-SiO: systems, and it is found that activation energy can be expressed as a linear function of the content of components, where the optical basicity of slag must be within the range of 0.58 to 0.68.展开更多
Several 1-vinyl-3-alkylimidazolium halogens [VRIM]X, which are functional materials with ethylenic bonds, were synthesized using the microwave-assisted synthesis method. Fourier transform infrared spectroscopy and 1H ...Several 1-vinyl-3-alkylimidazolium halogens [VRIM]X, which are functional materials with ethylenic bonds, were synthesized using the microwave-assisted synthesis method. Fourier transform infrared spectroscopy and 1H nuclear magnetic resonance spectroscopy were carded out to analyze the resultant structures. The electrochemical properties and solubility of [VRIM]Br were investigated and discussed in detail. The temperature dependence of pure [VRIM]Br over a wide temperature range of 298.15-323.15 K fitted the Arrhanius equation well. At certain low concentrations, the electrical conductivity of the [VRIM]Br solution significantly increased with increasing solution concentration. The electrical conductivities of the [VRIM]Br observed in water, methanol, and ethanol showed the trend σwater〉 σmethanol 〉σethanol Conductometry showed that the critical miceUe concentrations of the bromines in water, methanol, and ethanol were 6.8-6.9 × 10-6, 1.4-1.5 × 10-5, and 1.9-2.0×10-5 mol.L-1, respectively; these results indicate that [VRIM]Br is an excellent surfactant. The solubility of [VRIM]X in common solvents was determined at 293.15 K, and results indicated that a decrease in solubility could be observed with decreasing dielectric constant of the solvent, elongation of the alkyl chain of the cation, and increasing anion size. Solubility parameters were also determined according to the Hildebrand-Scoff equation.展开更多
文摘The searching about methods to connect the variables with each other to reach equations including multi variables. The dimensional analysis is a method to facilitate the solution of difficult mathematic equations and experimental formulas;therefore methods of simplifying the difficult equations and obtaining a new equation with different variables is needed. In this study will use 2 methods (statically with dimensionally analysis) to obtain electric conductivity of water of Euphrates river by multi parameters that are time (t), temperature (Te), density, viscosity, discharge and water depth in upstream of Alhindya barrage which located in Babylon governorate, Iraq during winter 2019. The equations were obtained for EC with Te and t by data were collected from Alhindya barrage office with R<sup>2</sup> = 0.999 and R<sup>2</sup> = 0.995 by statically ways. Dimension analysis was utilized via 2 stages. In first stage was obtained on equation of EC with respect to Te, water density (ρ) and dynamic viscosity (μ) with constant time, depth of water and discharge and we obtain on R<sup>2</sup> was 0.994 and R<sup>2</sup> = 0.986. In second stage was obtained formula of EC with respect to Te, water density (ρ), dynamic viscosity (μ), with variable time, depth of water and discharge with we obtain on R<sup>2</sup> = 0.945 and R<sup>2</sup> = 0.94. The result of research indicates that applying the dimension analysis to connect more than one variable with each other to find best solutions and best methods to facilitate the solving the equations. From dimension analysis gave a clear visualization of the association of several variables to give a result that helps measure the electrical conductivity of water in the absence of a water test device.
基金Funded by Changzhou Science and Technology Innovation Project(Nos.CC20140048,CC20130204)National Natural Science Foundation of China(No.51273027)2015 Research and Innovation Project for College Graduates of Jiangsu Province
文摘Ce-doped Bi2O3 nanopowders were prepared by reverse titration chemical coprecipitation from Bi^3+and Ce^(4+)containing aqueous solution.Techniques of X-ray diffraction(XRD),transmission electron microscopic(TEM)and Fourier transform infrared spectroscopy(FTIR)were employed to characterize the as-synthesized materials.The XRD patterns indicated that the peaks can be easily indexed toβ-Bi2O3 and no diffraction peaks of Ce or other impurity phases were detected in the prepared samples.The calculated average crystalline size decreased from 31.72 to 11.96 nm when the Ce content increased from 1 wt%to 10 wt%.The morphology changed from flake-like into the spherical-like with increase in Ce content.The electric conductivity of Ce-doped Bi2O3 electrolyte was also investigated by two probe DC method.Conductivity analysis exhibited that the rate of conductivity increased with increasing Ce^2+ratio,when the Ce concentration was up to 5 wt%,the as-synthesized Ce-doped Bi2O3 electrolyte showed the maximum value of conductivity(0.295 S?cm^(–1)).
文摘In this paper, instead of with the more expensive Fourier Transform Infrared Spectrometer(FTIR) a new technique of Temperature Programmed Transient Response(TP-TR) has been used with gas chromatography. Therefore, the TP-TR will be applied more widespreadly than ever before. With the technique of TP-TR and electric conductivity, the study is on the reaction mechanism and the adsorption behavior of the reactants and products to the present catalyst Mo-V-Nb/Al_2O_3 in the reaction from ethane through oxydehydrogenation to ethylene as the product. By Range-Kutta-Gill and Margarat methods, the kinetic parameters of the reaction elementary steps (i.e. rate constants, active energies and frequency factors) have been evaluated. The mathematical treatment coincides with the experimental results.
基金supported by the Fundamental Research Funds for the Central Universities(No.20CX05005A)the Major Scientific and Technological Projects of CNPC(No.ZD2019-184-001)+2 种基金the PetroChina Innovation Foundation(No.2018D-5007-0214)the Shandong Provincial Natural Science Foundation(No.ZR2019MEE095)the National Natural Science Foundation of China(No.42174141).
文摘Clays have considerable influence on the electrical properties of hydrate-bearing sediments.It is desirable to understand the electrical properties of hydrate-bearing clayey sediments and to build hydrate saturation(S_(h))models for reservoir evaluation and monitoring.The electrical properties of tetrahydrofuran-hydrate-bearing sediments with montmorillonite are characterized by complex conductivity at frequencies from 0.01 Hz to 1 kHz.The effects of clay and Sh on the complex conductivity were analyzed.A decrease and increase in electrical conductance result from the clay-swelling-induced blockage and ion migration in the electrical double layer(EDL),respectively.The quadrature conductivity increases with the clay content up to 10%because of the increased surface site density of counterions in EDL.Both the in-phase conductivity and quadrature conductivity decrease consistently with increasing Sh from 0.50 to 0.90.Three sets of models for Sh evaluation were developed.The model based on the Simandoux equation outperforms Archie’s formula,with a root-mean-square error(E_(RMS))of 1.8%and 3.9%,respectively,highlighting the clay effects on the in-phase conductivity.The fre-quency effect correlations based on in-phase and quadrature conductivities exhibit inferior performance(E_(RMS)=11.6%and 13.2%,re-spectively)due to the challenge of choosing an appropriate pair of frequencies and intrinsic uncertainties from two measurements.The second-order Cole-Cole formula can be used to fit the complex-conductivity spectra.One pair of inverted Cole-Cole parameters,i.e.,characteristic time and chargeability,is employed to predict S_(h) with an E_(RMS) of 5.05%and 9.05%,respectively.
基金supported substantially by the Southwest Jiaotong University for Material and Financial Support。
文摘Graphene(Gr)has unique properties including high electrical conductivity;Thus,graphene/copper(Gr/Cu)composites have attracted increasing attention to replace traditional Cu for electrical applications. However,the problem of how to control graphene to form desired Gr/Cu composite is not well solved. This paper aims at exploring the best parameters for preparing graphene with different layers on Cu foil by chemical vapor deposition(CVD)method and studying the effects of different layers graphene on Gr/Cu composite’s electrical conductivity. Graphene grown on single-sided and double-sided copper was prepared for Gr/Cu and Gr/Cu/Gr composites. The resultant electrical conductivity of Gr/Cu composites increased with decreasing graphene layers and increasing graphene volume fraction. The Gr/Cu/Gr composite with monolayer graphene owns volume fraction of less than 0.002%,producing the best electrical conductivity up to59.8 ×10^(6)S/m,equivalent to 104.5% IACS and 105.3% pure Cu foil.
文摘Open-source and free tools are readily available to the public to process data and assist producers in making management decisions related to agricultural landscapes. On-the-go soil sensors are being used as a proxy to develop digital soil maps because of the data they can collect and their ability to cover a large area quickly. Machine learning, a subcomponent of artificial intelligence, makes predictions from data. Intermixing open-source tools, on-the-go sensor technologies, and machine learning may improve Mississippi soil mapping and crop production. This study aimed to evaluate machine learning for mapping apparent soil electrical conductivity (EC<sub>a</sub>) collected with an on-the-go sensor system at two sites (i.e., MF2, MF9) on a research farm in Mississippi. Machine learning tools (support vector machine) incorporated in Smart-Map, an open-source application, were used to evaluate the sites and derive the apparent electrical conductivity maps. Autocorrelation of the shallow (EC<sub>as</sub>) and deep (EC<sub>ad</sub>) readings was statistically significant at both locations (Moran’s I, p 0.001);however, the spatial correlation was greater at MF2. According to the leave-one-out cross-validation results, the best models were developed for EC<sub>as</sub> versus EC<sub>ad</sub>. Spatial patterns were observed for the EC<sub>as</sub> and EC<sub>ad</sub> readings in both fields. The patterns observed for the EC<sub>ad</sub> readings were more distinct than the EC<sub>as</sub> measurements. The research results indicated that machine learning was valuable for deriving apparent electrical conductivity maps in two Mississippi fields. Location and depth played a role in the machine learner’s ability to develop maps.
基金The fnancial supports from the National Natural Science Foundation of China(Grant No.51209196)the Science and Technology Project of Ministry of Transport of China(Grant No.20113184931700)
文摘Natural soils of various types have different electrical properties due to the composition,structure,water content,and temperature.In order to investigate the electrical properties of lateritic soil,electrical conductivity experiments have been conducted on a self-developed testing device.Test results show that the electrical conductivity of laterite increases with the increase of water content,degree of saturation and dry density.When the water content is below the optimum water content,the electrical conductivity of soils increases nonlinearly and the variation rate increases dramatically.However,when the water content,degree of saturation,or dry density increases to a certain value,the electrical conductivity tends to be a constant.In addition,soil electrical conductivity increases with the increase of temperature,and it is observed that the electrical conductivity decreases with the increase of the number of wetting–drying cycles.
基金financially supported by the National Natural Science Foundation of China (Nos. 51564015 and 51674126)the Graduate Student Innovation Special Fund of Jiangxi Province (YC2015-B064)+2 种基金the Science and Technology Research Project of Jiangxi Department of Education (GJJ150664)the Outstanding Doctoral Dissertation Project Fund of JXUST (YB2016007)the Scientific Research Fund of JXUST (NSFJ2014-G09)
文摘Metal Sm has been widely used in making Al–Sm magnet alloy materials. Conventional distillation technology to produce Sm has the disadvantages of low productivity, high costs, and pollution generation. The objective of this study was to develop a molten salt electrolyte system to produce Al–Sm alloy directly, with focus on the electrical conductivity and optimal operating conditions to minimize the energy consumption. The continuously varying cell constant(CVCC) technique was used to measure the conductivity for the Na3AlF6–AlF3–LiF–MgF2–Al2O3–Sm2O3electrolysis medium in the temperature range from 905 to 1055°C. The temperature(t) and the addition of Al2O3(W(Al2O3)), Sm2O3(W(Sm2O3)), and a combination of Al2O3and Sm2O3into the basic fluoride system were examined with respect to their effects on the conductivity(κ) and activation energy. The experimental results showed that the molten electrolyte conductivity increases with increasing temperature(t) and decreases with the addition of Al2O3or Sm2O3or both. We concluded that the optimal operation conditions for Al–Sm intermediate alloy production in the Na3AlF6–AlF3–LiF–MgF2–Al2O3–Sm2O3system are W(Al2O3) + W(Sm2O3) = 3wt%, W(Al2O3):W(Sm2O3) = 7:3, and a temperature of 965 to 995°C, which results in satisfactory conductivity, low fluoride evaporation losses, and low energy consumption.
基金This research project was granted by the Knowledge-Innovation Program sponsored by the Chinese Academy of Sciences(KZCX3-SW-124).
文摘At presure 1.0-4.0 GPa and temperature 1073-1423 K and under oxygen partial pressure conditions, a YJ-3000t multi-anvil solid high-pressure apparatus and Sarltron-1260 Impedance/Gain-Phase analyzer were employed to conduct an in-situ measurement of the electrical conductivity of orthopyroxene. The buffering reagents consist of Ni+NiO, Fe+Fe3O4, Fe+FeO and Mo+MoO2 in order to control the environmental oxygen fugacity. Experimental results made clear that: (1) within the measuring frequency range from 10-1 to 106 Hz, the complex impedance (R) is of intensive dependence on the frequency; (2) The electrical conductivity (a) tends to increase along to the rise of temperature (T), and Log a vs. 1/ T fit the Arrenhius linear relations; (3) Under the control of oxygen buffer Fe+Fe3O4, with the rise of pressure, the activation enthalpy tends to increase whereas the electrical conductivity tends to decrease. The activation energy and activation volume of the main current carders of orthopyroxene have been obtained, which are (1.715±0.035) eV and (0.03±0.01) cm^3/mol, respectively; (4) Under given pressure and temperature, the electrical conductivity tends to increase with increasing oxygen fugacity, while under given pressure the activation enthalpy tends to decrease with increasing oxygen fugacity; and (5) The sample's small polarons mechanism has provided a reasonable explanations to the conduction behavior at high temperature and high pressure.
文摘The frequency and temperature dependent electrical conductivity measurements for heat-treated binary glass system with composition of (lO0-x)Bi203-xBaTi03 (x = 20, 30, 40 and 50, in mol%) were carried out. The glass was prepared by melt quenching technique and their corresponding glass-ceramic nanocomposites were obtained by suitable heat treatment. Nanostructured behavior and electrical properties of these glasses and their corresponding glass-ceramic nanocomposites were studied. X-ray diffraction (XRD) and differential scanning calorimetry confirmed the amorphous nature of the glasses. Moreover, XRD patterns of the samples indicate nanocrystallites embedded in the glass matrix. The Fourier transform infrared spectroscopy (FT-IR) spectral analysis showed that the band positions of glass system are within the wave number range of Bi06, Bi03 and Ti06 structural units. It is observed that the electrical conductivity is enhanced by 102-103 times in the transparent glass-ceramic nanocomposite phase. With further heat treatment, the conductivity decreased considerably in the stage of glass-ceramic nanocomposite phase as compared with the glassy phase sample. Therefore, partially devitrified phase is more suitable as cathode material in secondary batteries compared to its vitreous or fully crystalline counterpart. The conduction mechanism was confirmed to obey the adiabatic small polaron hopping (SPH). AC conductivity measurements were performed as a function of temperature and frequency, showing a very slow increasing rate at low temperatures and then a fast rate at higher temperatures.
文摘BN ceramic is an advanced engineering ceramics with excellent thermal shock resistance, good workability and excellent dielectricity.TiB 2 ceramic has excellent electric conductivity,high melting points, and corrosion resistance to molten metal.Therefore,the composite consisting of BN and TiB 2 ceramics is expected to have a combination of above mentioned properties,thereby can be used as self heating crucible.In this paper,hot pressing technology was used to fabricate the high performance BN TiB 2 composite materials.microstructure and electric conducting mechanism were studied,and the relationship between the microstructure and physical property was discussed.The results show that the microstructure of composites has a great influence on the physical property of composites.The BN TiB 2 composites with excellent mechanical strength and stable resistivity can be obtained by optimizing the processing parameter and controlling the microstructure of composites.
基金a Chinese Ministry of Education "Changjiang" Innovative Research Team Program(IRT1169)"the Fundamental Research Funds for the Central Universities" (303-47110117,303-47110118,2012-yb-04,and 2012-Ia-008)+4 种基金NCET(NCET-11-0688)RFDP(20110143120006)NSFHB(2011CDB429)NFSC(51101115)Innovative Research Funds of SKLWUT(2011-la-024,2012-Ia-008,2011-PY-2,2011-PY-3)
文摘Monolayer chemically converted graphene (CCG) nanosheets can be homogeneously self-assembled onto silicon wafer modified by 3-aminopr- opyl triethoxysilane (APTES) to form very thin graphene film. The CCG film was characterized by FT-IR, XRD, SEM, TEM and AFM. Results show that CCG sheets formed monolayer film after assembled onto silicon wafer and there is a very tight chemical bond between sheets and wafer. Furthermore, the electrical measurements revealed that the monolayer graphene film has an excellent electrical conductivity.
基金supported by the National Natural Science Foundation of China(40861020)the Natural Science Foundation of Xinjiang(200821128)+1 种基金the Key Laboratory of Oasis Ecology in Xinjiang University(XJDX0201-2008-03)the Fund of Young Teachers Scientific Research in Xinjiang University(QN070122),China
文摘In order to assess the effects of chemical properties of soil salinity on electrical conductivity of 1:5 soil/water extract (EC1:5), the study focused on revealing the main chemical factors contributing to EC of soil extracts and their relative importance. The relationship between EC1:5 and the chemical properties of soil salinity in the delta oasis of Weigan and Kuqa rivers, China, were studied using path coefficient analysis, a path analysis method. We studied each key element affecting EC1:5 either directly or indirectly. The results obtained show that the salt content, total dissolved solids (TDS), and the sum of the sodium ion concentration and the kalium ion concentration are the most influential factors on 1:5 soil/ water extract (EC1:5) in the 0-10 cm and the 30-50 cm soil layer. The results show that the sequence of direct path coefficients in the 0-10 cm and the 30-50 cm soil layers on soil conductivity is TDS→Na^+ + K^+→Salt content→Ca^2+→Cl-→the sodium dianion ratio (SDR)→pH→ SO4^2-→HCO3^-→Mg^2+→the soluble sodium percentage (SSP) sodium absorption ratio (SAR) and TDS→Salt content→Na^+ + K^+→Ca^2+→SDR→Mg^2+→HCO3^-→SSP→pH→SO4^2-→SAR→Cl^-. The salt content, chlorine ion, and SAR are the main factors affecting 1:5 soil/water extract (EC1:5) in the 10-30 centimeter soil layer. The order of direct path coefficients result is as follows: Salt content→Cl^-→SAR→SSP→TDS→Ca^2+→Mg^2+= SO4^2-→HCO3^-→pH→SDR→Na^- + K^+. Moreover, the effects of HCO3^-, pH were very weak. Though the direct path coefficients between EC1:5 and SAR, SO4^2- and Ca^2+ were not high, influence of other chemical factors caused the coefficients to increase, making the summation of their direct and indirect path coefficients relatively high. The models of the different soil layers were structured separately. Evidences showed that multiple regression relations between EC1:5 and most of the primary factors had sound reliability and very good accuracy. The research results can serve as a reference to the scientific management amelioration and utilization of saline in the Delta Oasis of Weigan and Kuqa rivers.
基金supported by the Program for New Century Excellent Talents in China Universities(NECT-04-0202)the Fok Ying Tung Foundation(No.104016)
文摘The changes of electrical conductivity (resistance) between Sn-3.0Ag-0.5Cu solder joints and printed circuit board (PCB) assembly during aging at 125℃ were investigated by the four-point probe technique. The microstructural characterizations of interfacial layers between the solder matrix and the substrate were examined by optical microscopy and scanning electronic microscopy. Different types of specimens were designed to consider several factors. The experimental results indicate that electrical conductivities (resistances) and residual shear strengths of the solder joint specimens significantly decrease after 1000 h during isothermal aging. Microcracks generate in the solder matrix at the first 250 h. Besides, the evolutions of microstructural characterizations at the interface and the matrix of solder joints were noted in this research.
文摘The effect of heat treatment on electrical conductivity of Cu alloy containing Ni, Al, and rare earth(Ce) alloying elements was studied by metallographic microscope, TEM, SEM/EDS and conductance instrument. The results indicate that heat treatment can improve the electrical conductivity of the material due to the reducing of the solid solution of Cr element in Cu matrix. The better conductivity was obtained after getting solid solution at 980 ℃ for 1 h, and then aging at 500 ℃ for 4 h.
文摘Polyaluminium chlorides with sulfate ion(PACS) were prepared by using AlCl 3·6H 2O, Al(SO 4) 3·18H 2O and Na 2CO 3 as raw materials. The effects of basicity ( r ), Al 3+ /SO 4 2- molar ratio and aging time on the morphology of PACS were observed by transmission electrical microscope. The influence of aging time on charge neutralization and coagulation effect of PACS was studied. The effects of basicity ( r ), Al 3+ /SO 4 2- molar ratio and aging time on the electrical conductivity of PACS solution were also investigated. The experimental results show that the degree of polymerization of polyaluminium chloride(PAC) increases when SO 4 2- ion is added. The higher the basicity( r ) and the longer the aging time, the larger the size of polymer PACS. The ability of PACS neutralizing the charge on Kaolinite decreases with the increase of aging time. The electrical conductivity of PACS solution(the concentration of Al 3+ ion is 0.18 mol/L) with different aging time is the function of the basicity and Al 3+ /SO 4 2- molar ratios and has its maximum at r =0.5 and Al 3+ /SO 4 2- =12.
基金supported by the National Natural Science Foundation of China (50204007)Program for New Century Excellent Talents in University (NCET-07-0387)
文摘The La0.7Sr0.3CryMnzCo(1-y-z)O3-δ samples were prepared by solid state reaction.The phases,microstructure and properties of the samples were investigated by XRD,SEM,DC four-probe method and iodometry method.The single orthorhombic phase La0.7Sr0.3CryMnzCo(1-y-z)O3-δ perovskite oxides were obtained when sintered at l350 °C for 10 h.The oxygen nonstoichiometry of the materials varied inversely with the total electronic conductivity.The sample with composition of La0.7Sr0.3Cr0.5Mn0.35 Co0.15O3-δ had the maxima...
文摘The effects of rare earths on electric conductivity fusion welding-resistance and erosion-resistance by electric arc of copper-based compound material by adding different amount of rare earths to copper base to get copper based compound materials were studied. Rare earths improve active ability among interfaces and optimize organizational structures. The conductivity of samples with rare earths is obviously better than that of materials without them. Moreover, wear ability and oxidization resistance of materials with rare earths can be improved greatly. For copper contact head with rare earths, electric arc corrosion resistance and welding-melting resistance are improved. Such alloys also decrease resistance change with increasing temperature. But the adding quantity of rare earths should be appropriate and formed handicraft should be properly regulated.
基金supported by the National Natural Science Foundation of China (No.50774004)
文摘Electrical conductivity of molten slag is an important physicochemical property for designing the refming process in electric smelting furnaces. Though conductivities of many slag systems have been measured, the quantitative relationships of conductivity with slag composition and temperature are still very limited. In this article, the Arrhenius law was used to describe the experimental data of conductivities for CaO-MgO-Al2O3-SiO2, CaO-Al2O3-SiO2, CaO-MnO-AlEO3-SiO2, as well as CaO-MgO-MnO- Al2O3-SiO: systems, and it is found that activation energy can be expressed as a linear function of the content of components, where the optical basicity of slag must be within the range of 0.58 to 0.68.
基金Funded by the Special Funds of the National Natural Science Foundation of China(No.21174111)
文摘Several 1-vinyl-3-alkylimidazolium halogens [VRIM]X, which are functional materials with ethylenic bonds, were synthesized using the microwave-assisted synthesis method. Fourier transform infrared spectroscopy and 1H nuclear magnetic resonance spectroscopy were carded out to analyze the resultant structures. The electrochemical properties and solubility of [VRIM]Br were investigated and discussed in detail. The temperature dependence of pure [VRIM]Br over a wide temperature range of 298.15-323.15 K fitted the Arrhanius equation well. At certain low concentrations, the electrical conductivity of the [VRIM]Br solution significantly increased with increasing solution concentration. The electrical conductivities of the [VRIM]Br observed in water, methanol, and ethanol showed the trend σwater〉 σmethanol 〉σethanol Conductometry showed that the critical miceUe concentrations of the bromines in water, methanol, and ethanol were 6.8-6.9 × 10-6, 1.4-1.5 × 10-5, and 1.9-2.0×10-5 mol.L-1, respectively; these results indicate that [VRIM]Br is an excellent surfactant. The solubility of [VRIM]X in common solvents was determined at 293.15 K, and results indicated that a decrease in solubility could be observed with decreasing dielectric constant of the solvent, elongation of the alkyl chain of the cation, and increasing anion size. Solubility parameters were also determined according to the Hildebrand-Scoff equation.