scholarly journals ACTIVITY AND ACTIVITY COEFFICIENTS OF DISSOLVING PHASE OF HETEROGENEOUS ALLOY UNDER CONDITIONS OF LOCAL VOLTAMPEROMETRY

Author(s):  
Vyacheslav V. Slepushkin ◽  
Yuliya V. Rublinetskaya ◽  
Elena Yu Moshchenskaya ◽  
Boris I. Kashkarov

The new expressions for the activity coefficients of dissolving phase and for calibration curves i=f(С) are presented as the result of development of previous studies of an anode dissolution process of heterogeneous alloys at the conditions of local voltammetry.

2017 ◽  
Vol 72 (2) ◽  
pp. 203-205
Author(s):  
E. Yu. Moshchenskaya ◽  
V. V. Slepushkin ◽  
Yu. V. Rublinetskaya ◽  
B. I. Kashkarov

2015 ◽  
Vol 788 ◽  
pp. 11-16
Author(s):  
Boris A. Krasilnikov ◽  
Svetlana I. Vasilevskaya

This article is devoted to investigating a possibility of using electrochemical machining (ECM) technology in manufacturing of printed circuits. Some investigations into the anodic dissolution of copper in aqueous electrolytes under stationary conditions were conducted. The analysis of potentiodynamic polarization curve character allowed revealing both areas of active and passive copper dissolution as well as areas of only active and only passive dissolution. Electrolytes were identified and the concentration of electrolyte solutions where the dissolution process occurs in the above areas was determined. It is shown how to assess a degree of the ECM process localization in electrolytes with surface activation in the treatment area. A simplified function of the localization degree L = i 0 /i without regard for current efficiency was used in the research. Electrolytes with a high degree of electrochemical dissolution localization were revealed. Potential ranges for each of the electrolytes providing a maximum degree of the localization copper dissolution process localization were determined.


2020 ◽  
Author(s):  
Chendong Wang

BACKGROUND Perihilar cholangiocarcinoma (pCCA) is a highly aggressive malignancy with poor prognosis. Accurate prediction is of great significance for patients’ survival outcome. OBJECTIVE The present study aimed to propose a prognostic nomogram for predicting the overall survival (OS) for patients with pCCA. METHODS We conducted a retrospective analysis in a total of 940 patients enrolled from the Surveillance, Epidemiology, and End Results (SEER) program and developed a nomogram based on the prognostic factors identified from the cox regression analysis. Concordance index (C-index), risk group stratification and calibration curves were adopted to test the discrimination and calibration ability of the nomogram with bootstrap method. Decision curves were also plotted to evaluate net benefits in clinical use against TNM staging system. RESULTS On the basis of multivariate analysis, five independent prognostic factors including age, summary stage, surgery, chemotherapy, together with radiation were selected and entered into the nomogram model. The C-index of the model was significantly higher than TNM system in the training set (0.703 vs 0.572, P<0.001), which was also proved in the validation set (0.718 vs 0.588, P<0.001). The calibration curves for 1-, 2-, and 3-year OS probabilities exhibited good agreements between the nomogram-predicted and the actual observation. Decision curves displayed that the nomogram obtained more net benefits than TNM staging system in clinical context. The OS curves of two distinct risk groups stratified by nomogram-predicted survival outcome illustrated statistical difference. CONCLUSIONS We established and validated an easy-to-use prognostic nomogram, which can provide more accurate individualized prediction and assistance in decision making for pCCA patients.


1994 ◽  
Vol 59 (8) ◽  
pp. 1738-1744
Author(s):  
Vladislav Holba

The solubilities of tetraalkylammonium dianilinetetraisothiocyanatochromates(III) (alkyl = methyl, ethyl, 1-propyl, and 1-butyl) in water, water - methanol, water - tert-butyl alcohol and water - acetonitrile solutions were measured at 25 °C. The results were used to evaluate the activity coefficients and Gibbs energies of transfer of the saturating salts from water to the mixed systems. The Gibbs energies of transfer of the [Cr(C6H5NH2)2(NCS)4]- ion were obtained by means of known ionic transfer functions for the tetraalkylammonium ions based on the TATB assumption.


1989 ◽  
Vol 54 (11) ◽  
pp. 2840-2847 ◽  
Author(s):  
Ivona Malijevská ◽  
Alena Maštalková ◽  
Marie Sýsová

Isobaric equilibrium data (P = 101.3 kPa) for the system cyclohexane-acetic acid-propionic acid have been measured by two different analytical techniques. Activity coefficients calculated by simultaneous solving of equations for the chemical and phase equilibria were subjected to a consistency test based on inaccuracies determined from the error propagation law, and were correlated by Wilson’s equation. The activity coefficients measured were compared with those calculated from binary vapour-liquid equilibrium data and with values predicted by the UNIFAC method.


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