When the organic vapors absorbed to the surface of porous silicon(PS), capillary condensation takes place due to the porous structure of the PS layer, accordingly resulting in the effective refractive index changing. ...When the organic vapors absorbed to the surface of porous silicon(PS), capillary condensation takes place due to the porous structure of the PS layer, accordingly resulting in the effective refractive index changing. For PS multi-layer microcavities, the different resonant peaks shift in the reflectivity spectrum of porous silicon microcavities(PSMs). The optical sensing model is set up by applying Bruggeman effective medium approximation theory, capillary condensation process and transfer matrix theoretically analytical method of one-dimensional photonic crystals. At the same time, comprehensively researched on are the sensing characteristics of PSMs which are exposed to give concentration organic vapors. At last, made is the theoretical simulation for sensing model of the PSMs in case of saturation by using computer numerical calculation, and found is the linearity relation between the refractive index of organic solvent and the peak-shift. At the same time deduced is the peak-shift as a function of the concentration of ethanol vapors.展开更多
Conductive additives are used in the cathode of a Li-ion battery to improve electrical conductivity.However,these additives can negatively impact the ionic conductivity and specific capacity of the battery.Therefore,d...Conductive additives are used in the cathode of a Li-ion battery to improve electrical conductivity.However,these additives can negatively impact the ionic conductivity and specific capacity of the battery.Therefore,design of additive-free cathodes is gaining attention in the research community.In this paper,we explore the effective electrical conductivity of randomly generated two-phase conductive-free cathode microstructures using a mathematical homogenization method.Over thousand microstructures with various combinations of particle size,volume fraction and conductivity ratios are considered to evaluate effective electrical conductivity values using this method.An explicit formulation is proposed based on the results to provide a simple method for evaluation of the effective conductivity values.The intrinsic properties of each phase of the microstructure are used to obtain the effective electrical conductivity values.With the microstructure geometry information being utilized for the evaluation of the effective properties,the results obtained from this formulation are expected to be more accurate and reliable than those obtained using the popular Bruggeman’s approximation,providing better estimates of discharge characteristics.Finally,the significance of incorporation of micro-structural information to model cathodes is highlighted by studying the discharge characteristics of Li-ion battery system.展开更多
Using time domain reflectometry (TDR),dielectric relaxation studies were carried out on binary mixtures of amides (N-methylformamide (NMF) and N,N-dimethylformamide (DMF)) with alcohols (1-butanol,1-pentanol,1-hexanol...Using time domain reflectometry (TDR),dielectric relaxation studies were carried out on binary mixtures of amides (N-methylformamide (NMF) and N,N-dimethylformamide (DMF)) with alcohols (1-butanol,1-pentanol,1-hexanol,1-heptanol,1-octanol,and 1-decanol) for various concentrations over the frequency range from 10 MHz to 10 GHz at 303 K. The Kirkwood correlation factor and excess dielectric constant properties were determined and discussed to yield information on the molecular interactions of the systems. The relaxation time varied with the chain length of alcohols and substituted amides were noticed. The Bruggeman plot shows a deviation from linearity. This deviation was attributed to some sort of molecular interaction which may take place between the alcohols and substituted amides. The excess static permittivity and excess inverse relaxation time values varied from negative to positive for all the systems indicating that the solute-solvent interaction existed between alcohols and substituted amides for all the dynamics of the mixture.展开更多
文摘When the organic vapors absorbed to the surface of porous silicon(PS), capillary condensation takes place due to the porous structure of the PS layer, accordingly resulting in the effective refractive index changing. For PS multi-layer microcavities, the different resonant peaks shift in the reflectivity spectrum of porous silicon microcavities(PSMs). The optical sensing model is set up by applying Bruggeman effective medium approximation theory, capillary condensation process and transfer matrix theoretically analytical method of one-dimensional photonic crystals. At the same time, comprehensively researched on are the sensing characteristics of PSMs which are exposed to give concentration organic vapors. At last, made is the theoretical simulation for sensing model of the PSMs in case of saturation by using computer numerical calculation, and found is the linearity relation between the refractive index of organic solvent and the peak-shift. At the same time deduced is the peak-shift as a function of the concentration of ethanol vapors.
文摘Conductive additives are used in the cathode of a Li-ion battery to improve electrical conductivity.However,these additives can negatively impact the ionic conductivity and specific capacity of the battery.Therefore,design of additive-free cathodes is gaining attention in the research community.In this paper,we explore the effective electrical conductivity of randomly generated two-phase conductive-free cathode microstructures using a mathematical homogenization method.Over thousand microstructures with various combinations of particle size,volume fraction and conductivity ratios are considered to evaluate effective electrical conductivity values using this method.An explicit formulation is proposed based on the results to provide a simple method for evaluation of the effective conductivity values.The intrinsic properties of each phase of the microstructure are used to obtain the effective electrical conductivity values.With the microstructure geometry information being utilized for the evaluation of the effective properties,the results obtained from this formulation are expected to be more accurate and reliable than those obtained using the popular Bruggeman’s approximation,providing better estimates of discharge characteristics.Finally,the significance of incorporation of micro-structural information to model cathodes is highlighted by studying the discharge characteristics of Li-ion battery system.
文摘Using time domain reflectometry (TDR),dielectric relaxation studies were carried out on binary mixtures of amides (N-methylformamide (NMF) and N,N-dimethylformamide (DMF)) with alcohols (1-butanol,1-pentanol,1-hexanol,1-heptanol,1-octanol,and 1-decanol) for various concentrations over the frequency range from 10 MHz to 10 GHz at 303 K. The Kirkwood correlation factor and excess dielectric constant properties were determined and discussed to yield information on the molecular interactions of the systems. The relaxation time varied with the chain length of alcohols and substituted amides were noticed. The Bruggeman plot shows a deviation from linearity. This deviation was attributed to some sort of molecular interaction which may take place between the alcohols and substituted amides. The excess static permittivity and excess inverse relaxation time values varied from negative to positive for all the systems indicating that the solute-solvent interaction existed between alcohols and substituted amides for all the dynamics of the mixture.
