A Mathematica interface for FormCalc-generated code

This note describes a Mathematica interface for Fortran code generated by FormCalc. The interfacing code is set up automatically so that only minuscule changes in the driver files are required. The interface makes a function to compute the cross-section or decay rate available in Mathematica. This function depends on the model parameters chosen for interfacing in the Fortran code.     

Impedance match for Stirling type cryocoolers

Impedance match in Stirling type cryocoolers is important for the compressor efficiency and available acoustic power. This paper generalizes the basic principles concerning the efficiency and acoustic power output of the linear compressor. Starting from basic governing equations and mainly from the viewpoint of energy balance, the physical mechanisms behind the principles are clearly shown. Specially, this paper focuses on the impedance match for an existing compressor, where the current limit and displacement limit should also be taken into consideration when selecting a suitable impedance. Some case studies based on a commercial compressor are also provided for a deep understanding.     

Electrochemical behavior of organic and inorganic complexes of Zn(II) as corrosion inhibitors for mild steel: Solution phase study

This work intends to study inhibitive performance of organic and inorganic complexes of Zn(II) using electrochemical techniques along with surface analysis. In this regard, inorganic zinc aluminum polyphosphate pigment as modified zinc phosphate and zinc acetylacetonate and benzimidazole mixture representing organic replacement of zinc phosphate were employed. Through taking advantage of electrochemical impedance spectroscopy and DC polarization, two mentioned approaches were indicated to be efficient. Charge transfer resistance and corrosion current density values exhibited superiority of zinc aluminum polyphosphate and mixture of zinc acetylacetonate and benzimidazole compared to zinc phosphate and also zinc acetylacetonate and benzimidazole as individual inhibitors. Corrosion inhibition efficiencies calculated based on charge transfer resistance in consistent with those calculated from corrosion current density showed the following sequence; zinc aluminum polyphosphate > mixture of zinc acetylacetonate and benzimidazole > zinc acetylacetonate > zinc phosphate > benzimidazole. Showing film formation, surface analysis SEM/EDX confirmed the results obtained by electrochemical methods.     

Enhanced conductivity of bacterial cellulose films reinforced with NH4I-doped graphene oxide

ABSTRACT

Bacterial cellulose (BC) films reinforced with reduced graphene oxide (RGO) platelets were investigated to assess their potential application as solid polymeric electrolytes. BC-RGO composites were further doped with NH₄I at different concentrations to evaluate the effect of NH₄I doping on the conductivity. Scanning electron microscopy images confirmed that GO addition did not alter BC coherent three-dimensional morphology. Electrochemical impedance spectroscopy studies revealed that the ionic conductivity increased with the ammonium iodide salt concentration. The highest conductivity found was 1.32 × 10^?4 S/cm for the samples doped with 5% NH₄I, suggesting that BC-RGO can be a promising candidate for electrochemical applications.     

A low-power readout circuit for nanowire based hydrogen sensor

This paper presents a fully integrated lock-in amplifier intended for nanowire gas sensing. The nanowire will change its conductivity according to the concentration of an absorbing gas. To ensure an accurate nanowire impedance measurement, a lock-in technique is implemented to attenuate the low frequency noise and offset by synchronous demodulation or phase-sensitive detection (PSD). The dual-channel lock-in amplifier also provides both resistive and capacitive information of the nanowire in separate channels. Measurement results of test resistors and capacitors show a 2% resolution in the resistance range 10-40 kΩ and a 3% resolution in the capacitance range 0.5-1.8 nF. Moreover, a 28.7-32.1 kΩ impedance variation was measured through the lock-in amplifier for a single palladium nanowire that was exposed to a decreasing hydrogen concentration (10% H₂ in N₂ to air). The chip has been implemented with UMC 0.18 μm CMOS technology and occupies an area of 2 mm². The power consumption of the readout circuit is 2 mW from a 1.8 V supply.     

Thick mesoporous TiO2 films through a sol–gel method involving a non-ionic surfactant: Characterization and enhanced performance for water photo-electrolysis

A method for the preparation of TiO₂ thick films made of anatase nanocrystallites and featuring a mesoporous structure is described. Modification of a typical sol–gel synthesis that uses Titanium (IV) isopropoxide (TTIP) as precursor, through both the incorporation of a non-ionic surfactant (Tween 20) and the optimization of thermal treatments, allows to increase the thickness of each spin-coated layer, and to obtain by successive runs porous, transparent, homogeneous and crackless films with thickness up to 1.2 μm. The effect of the changing the Tween 20/TTIP ratio (R, ranging from 0.25 to 1.00) on the crystallographic, morphological and optical properties has been studied by X-ray Diffraction, N₂ adsorption, UV–Visible Spectroscopy and Field Emission Scanning Electron Microscopy, in both powder and film form. The size of particles decreases slightly with increasing R, while the specific surface area increases somewhat. For all the R values, including R = 0, nanoparticles behave as direct semiconductors, in contrast with bulk anatase: changes in the band gap extent caused by the porous structure are negligible. Photo-electrochemical performance and carrier dynamics were studied using the films as anodes for the water photo-electrolysis reaction by means of Linear Sweep Voltammetry, Amperometry and Electrochemical Impedance Spectroscopy. Increasing R values improves the photo-catalytic performance of the TiO₂ films and leads to a comprehensive faster charge transfer at the oxide–solution interface, so that those with R = 1 offer highest performance, due to the combination of both higher thickness and improved quality of the material.     

Effect of mixing sequence on the properties of carbon black and silica filled rubber

Abstract

The mixing sequence is of great importance when silane coupling agents are employed for improvement of reinforcement and tyre performances. Y-sequence mixing has the potential of making it possible to produce different compounds effectively by combining one silica master-batch with various carbon black masterbatches, provided that the compound's properties are not affected negatively compared to conventional mixing processes. We have, therefore, investigated the Y-sequence mixing in terms of various compound properties such as Mooney value, modulus, tensile strength, elongation at break, hardness and visco-elasticity, and compared the results with those obtained using multistep sequence mixing and the all-in-one approach. The results have showed that the compound properties from the Y-sequence mixing weresimilar to thoseobtained by the multistep sequence,and superior to the all-in-one mixing sequence. It is thus concluded that the Y-sequence mixing has potential as a more economical alternative to currently employed mixing processes.     

接口控制文件仿真方法研究

针对装甲车辆复杂的电子信息系统的接口控制文件,若要建立其整个系统的仿真模型,不但周期长,而且分工建立起来的各个模型由于思想方案的不同,会给仿真过程带来很多麻烦,因此采用一种根据接口控制文件自动建立其UML系统模型的方法,通过将自动生成的模型联合详细设计模型一起下载到主仿真机,并联合其它相关工具来完成ICD的自动仿真.结果表明该方法是可行的,不仅很好地解决了仿真过程中ICD数据修改后模型需要重新建立的问题,而且实现了ICD仿真的自动化.     

Studies on morphological and electrical properties of Al incorporated combusted iron oxide

The aluminium incorporated iron oxide samples were prepared by combustion route using aluminium nitrate and ferric trichloride as precursors. The samples were characterized for their morphological, dielectrical, impedance and thermal conductivity properties as a function of temperature. A strong low frequency dielectric dispersion is found to exist in these samples; this is ascribed to the presence of the ionized space charge carriers such as oxygen ion vacancies and interfacial polarization. The room temperature dielectric constant and the loss tangent (tan δ) at 1 kHz are 315 and 0.0855 for optimized 10 at.% Al:Fe₂O₃ sample, respectively. The frequency analysis of dielectric and ac conduction properties of these samples suggests the conduction process in these samples to be via oxygen ion vacancy motion through various defect sites. Impedance spectroscopy is used to characterize the electrical behavior. Results indicate that the relaxation mechanism of the material is temperature and frequency dependent and has dominant bulk contribution in different temperature ranges.     

The influence of some new 2,5-disubstituted 1,3,4-thiadiazoles on the corrosion behaviour of mild steel in 1 M HCl solution: AC impedance study and theoretical approach

The new 2,5-disubstituted 1,3,4-thiadiazoles were investigated as corrosion inhibitors of mild steel in 1 M HCl using AC impedance technique. Four of these compounds exhibit good inhibition properties, while two of them, 2,5-bis(4-nitrophenyl)-1,3,4-thiadiazole and 2,5-bis(4-chlorophenyl)-1,3,4-thiadiazole, stimulate the corrosion process especially at low concentrations. The experimental data obtained from this method show a frequency distribution and therefore a modelling element with frequency dispersion behaviour, a constant phase element (CPE) has been used. Possible correlations between experimental inhibition efficiencies and quantum chemical parameters such as dipole moment (μ), highest occupied (E_HOMO) and lowest unoccupied (E_LUMO) molecular orbitals were investigated. The models of the inhibitors were optimised with the Density Functional Theory formalism (DFT) using hybrid B3LYP/6-31G (2d,2p) as a higher level of theory. The Quantitative Structure Activity Relationship (QSAR) approach has been used and composite index of some quantum chemical parameters were constructed in order to characterize the inhibition performance of the tested molecules.