Approximate migration coefficient of percolated interfacial transition zone by using the accelerated chloride migration test

In this study, the electrochemical technique is applied to accelerate chloride ion migration in cement-based material to estimate its migration coefficient. In order to investigate the chloride migration coefficient of percolated interfacial transition zone (ITZ) on the chloride migration coefficient of specimen, specimens with cylindrical aggregates of the same height as the specimen were cast and tested. In this study, the volume fraction of aggregate is constant and the varied lateral surface area of the aggregate cylinder was obtained by using different diameters and number of aggregate. The chloride migration coefficient of cement-based material was determined experimentally as a function of the lateral surface area of aggregate. A model obtained for the migration coefficient of cement-based material and the regression analysis are used to determine the approximate chloride migration coefficient of the percolated ITZ. Based on the experimental and regression analytical results, the approximate percolated ITZ migration coefficient is 40.6, 35.5, and 37.8 times of the altered migration coefficient of matrix mortar for the water/cement (w/c) ratio of 0.35, 0.45, and 0.55, respectively.     

Electrical analysis of Li/SOCl2 cell connected with electrochemical capacitor

A Li/SOCl₂ bobbin-type cell, connected in parallel with an electrochemical capacitor, is investigated in order to overcome the voltage delay problem at high-rate discharge. In spite of the high internal resistance of the Li/SOCl₂ cell due to the passivation, the voltage delay is suppressed. Impedance measurements, in which the cell is separated from the capacitor, explain the suppression process clearly. The electrochemical capacitor operates as a high-current buffer and voltage-delay suppressor for the Li/SOCl₂ bobbin-type cell.     

形变CuCr合金的再结晶激活能

测试了CuCr合金经50%变形后在不同温度下再结晶晶粒体积分数为20%的时间,并根据公式G=G0exp[-Q/（RT）]计算出再结晶激活能.     

Electrochemical impedance spectroscopy analysis on aluminum alloys in EXCO solution

Electrochemical impedance spectroscopy (EIS) of Al‐Zn‐Mg‐Cu alloy in EXCO solution has been investigated. The results show that the impedance spectroscopy of the investigated electrode consists of two capacitive loops in the high and middle frequency domain respectively and an inductive loop in the low frequency domain at the first 30 h of immersion; the inductive arc disappears between 30 h and 60 h while it takes on at the low frequency domain at the last 36 h of the immersion time. A model based on the corrosion mechanism of the aluminum alloy and corroding morphology was proposed and applied to analyze the EIS results.     

Uncoupled non-linear equations method for determining kinetic parameters in case of hydrogen evolution reaction following Volmer–Heyrovsky–Tafel mechanism and Volmer–Heyrovsky mechanism

Hydrogen evolution reaction following Volmer–Heyrovsky–Tafel mechanism and not under diffusion control can be characterized using Tafel polarization and alternating current admittance data at various frequencies and at various overpotentials. Such reaction has four independent kinetic parameters. One empirical constant related to charge required for complete surface coverage is also involved.

In case of systems where only one time constant (related to charging/discharging of electrical double layer) is discerned, Volmer–Heyrovsky mechanism is assumed. Such systems have three independent kinetic parameters. Experimental data may provide maximum two independent conditions at a less cathodic overpotential and maximum one independent condition at a more cathodic overpotential.

A new approach to determine kinetic parameters utilizing these data and neglecting Heyrovsky and Tafel backward reaction rates has been proposed. The conditions involved are coupled non-linear equations. Uncoupled non-linear equations have been derived and iterated using Newton–Raphson method. The approach has been validated using literature data. The graphical relationships between experimental parameters and kinetic parameters have also been shown.     

PCC在水电站调速器和励磁装置上的应用

为了提高微机型水轮机调速器和同步发动机励磁装置的各项性能,提出了用可编程计算机控制器(PCC)研制调节器的方案.PCC不仅具有可编程逻辑控制器(PLC)的高可靠性,同时还具备PC机的高速性和多任务分时操作系统的特点.运行数据表明,用PCC为调节器研制的水轮机调速器和同步发电机励磁装置,其各项性能都达到或优于国家标准和部颁标准.     

Probing the reaction pathway of dehydrogenation of the LiNH2 + LiH mixture using in situ H NMR spectroscopy

Using variable temperature in situ ¹H NMR spectroscopy on a mixture of LiNH₂ + LiH that was mechanically activated using high-energy ball milling, the dehydrogenation of the LiNH₂ + LiH to Li₂NH + H₂ was investigated. The analysis indicates NH₃ release at a temperature as low as 30 °C and rapid reaction between NH₃ and LiH at 150 °C. The transition from NH₃ release to H₂ appearance accompanied by disappearance of NH₃ confirms unambiguously the two-step elementary reaction pathway proposed by other workers.     

A Generalized Algorithm of Training a Formal Neuron

Activation functions of neurons are represented in the form of power series. An algorithm that controls the slope of an activation function is proposed. The results of numerical experiments are given.     

Assessment of intergranular corrosion (IGC) in 316(N) stainless steel using electrochemical noise (EN) technique

In the present work, an attempt was made to demonstrate the use of electrochemical noise (EN) technique in assessment of intergranular corrosion (IGC) in 316(N) stainless steel (SS). Degree of sensitization (DOS) in the specimens aged at 923 K for 24, 40, 50 and 100 h was determined using double loop electrochemical potentiodynamic reactivation (DLEPR) technique. Immediately after applying a prior preconditioning treatment, current and potential noise measurements were made. The DOS was determined from standard deviation of current noise (σ_I) versus time plot and it was found to bear a good correlation with the values obtained by DLEPR. Shot noise analysis of the EN data confirmed the above results.