scholarly journals Electrochemical synthesis of Sn–Ag alloy coatings in sulphate solution

2019 ◽  
pp. 51-61
Author(s):  
Olga N. Vrublevskaya ◽  
Marina A. Shikun
Keyword(s):  
Electrochemical Reduction ◽  
Electrochemical Synthesis ◽  
Silver Content ◽  
Sulfate Electrolyte ◽  
Total Current ◽  
Current Yield ◽  
Optimal Conditions ◽  
Electrolyte Temperature ◽  
Temperature Growth ◽  
Contact Displacement

The optimal conditions for the electrochemical synthesis in the sulfate electrolyte of low-melting Sn–Ag alloy coatings used in the assembly of electronic equipment containing 7.1–8.3 at. % of silver and with total current yield of metals equal to 88.8–87.0 % are determined. It is established that electrochemical reduction of Sn(II) and Ag(I) on the surface of the alloy is accompanied by the process of contact displacement of Ag(I) with tin included into the coating. The process of contact displacement is intensified with the electrolyte temperature growth and leads to the increase in silver content in the alloy, to the appearance of dendrites on the surface of the coating due to its passivation.

scholarly journals The electrochemical synthesis of TiC reinforced Fe based composite powder from titanium-rich slag

2015 ◽  
Vol 39 (6) ◽  
pp. 4391-4397 ◽  
Author(s):  
Sun Lin ◽  
Song Qiushi ◽  
Xu Qian ◽  
Ning Zhiqiang ◽  
Lu Xionggang ◽  
...  
Keyword(s):  
Electrochemical Reduction ◽  
Electrochemical Synthesis ◽  
Composite Powder ◽  
Composite Particles

Nano-sized TiC reinforced Fe based composite particles with a multi-core microstructure were synthesized by electrochemical reduction.

Main Physiological Factors Affecting the Germination of Annona muricata L. Seeds

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 464d-464
Author(s):  
German Corchuelo ◽  
Hector Villamil
Keyword(s):  
Moisture Content ◽  
Experimental Unit ◽  
Annona Muricata ◽  
Optimal Conditions ◽  
Physiological Factors ◽  
Tropical Fruit ◽  
Temperature Growth ◽  
Factors Affecting ◽  
Randomized Design ◽  
Old Trees

Dormancy and latency factors such as moisture content, temperature, growth regulators, and seed-coat affecting germination of the Annona muricata L., a tropical fruit, were studied. Three types of fruits were used with presence of stylar residues (medium and big size) and absent of stylar residues. The fruits were taken from 4-year-old trees, which were naturally pollinated. A complete randomized design was used for the study, with 50 seeds per experimental unit and four replications per treatment. The variables measured were days and percent of germination, and average germination velocity. The seed germination was affected by the moisture and oxygen content, because the structure of the seed and their high content of the lipid in there. The length of the germination period was determinated by the concentration of the exogen hormones applied, the temperature range, the kind of scarification used, the substrate utilized and the moisture content present during the assays. Highly significant differences were found among treatments. The optimal conditions for germination (97.5%) were: 30 °C of temperature, no scarification, sand as substrate, and 750 ppm of gibberellic acid. The average of days to germination was 24.5 days. No significant differences were found for the different kind of fruits used in this assay. The results showed that this species presented characteristics of recalcitrant seeds.

The effect of halides, pseudohalides, and some organic substances on the initial rate of peroxodisulphate formation

1981 ◽  
Vol 46 (11) ◽  
pp. 2809-2817 ◽  
Author(s):  
Jan Balej ◽  
Martin Kadeřávek
Keyword(s):  
Anodic Polarization ◽  
Initial Rate ◽  
Polarization Curves ◽  
Oxidation Products ◽  
Total Current ◽  
Organic Substances ◽  
Current Yield ◽  
Platinum Anode ◽  
Low Degree ◽  
Total Current Density

The effects of various additions of halides, pseudohalides and selected organic substances on the overall anodic polarization curves and the polarization curves of oxygen evolution and peroxodisulphate formation were examined under conditions of low degree of sulphate-to-peroxodisulphate conversion. Of the tested substances, SCN- and CN- ions, thiourea, urea and acetonitrile have proved to cause the greatest increase in the current yields of peroxodisulphate. However, the current yield varies as a function of the concentration of additive and the total current density, and goes through a maximum in both cases. The observed phenomena are discussed in terms of potential-dependent adsorption of additives or their oxidation products or intermediates on the oxidized surface of platinum anode.

Polarographic and voltammetric determination of 6-nitrobenzimidazole and mechanism of its electrochemical reduction

2009 ◽  
Vol 74 (10) ◽  
pp. 1443-1454 ◽  
Author(s):  
Dana Deýlová ◽  
Jiří Barek ◽  
Vlastimil Vyskočil
Keyword(s):  
Electrochemical Reduction ◽  
Mercury Electrode ◽  
Differential Pulse ◽  
Differential Pulse Polarography ◽  
Optimal Conditions ◽  
Pulse Polarography ◽  
Dropping Mercury Electrode ◽  
Constant Potential ◽  
Pulse Voltammetry

Optimal conditions were found for the determination of 6-nitrobenzimidazole by tast polarography (at 1 × 10–4–1 × 10–6 mol l–1), by differential pulse polarography at dropping mercury electrode (at 1 × 10–4–1 × 10–7 mol l–1), and by differential pulse voltammetry at hanging mercury drop electrode (at 1 × 10–4–1 × 10–8 mol l–1). Practical applicability of the developed methods was verified on the determination of 6-nitrobenzimidazole in drinking water (at 10–8 mol l–1). Coulometry at constant potential and cyclic voltammetry were used for elucidation of the mechanism of electrochemical reduction.

scholarly journals Electrochemical synthesis of flat-[Ga13−xInx(μ3-OH)6(μ-OH)18(H2O)24(NO3)15] clusters as aqueous precursors for solution-processed semiconductors

2014 ◽  
Vol 2 (40) ◽  
pp. 8492-8496 ◽  
Author(s):  
Matthew E. Carnes ◽  
Christopher C. Knutson ◽  
Athavan Nadarajah ◽  
Milton N. Jackson ◽  
Anna F. Oliveri ◽  
...  
Keyword(s):  
Thin Film ◽  
Electrochemical Reduction ◽  
Electrochemical Synthesis ◽  
Thin Film Transistors ◽  
Solution Processed ◽  
Indium Gallium

Electrochemical reduction is used to synthesize indium-gallium-hydroxide-nitrate nanoclusters which are shown to be promising precursors for thin-film transistors.

Amorphous silica coating on α-alumina particles

1995 ◽  
Vol 53 ◽  
pp. 210-211
Author(s):  
J. W. Mellowes ◽  
C. M. Chun ◽  
I. A. Aksay
Keyword(s):  
Amorphous Silica ◽  
Heterogeneous Nucleation ◽  
Homogeneous Nucleation ◽  
Silica Coating ◽  
Full Density ◽  
Optimal Conditions ◽  
Fine Grained ◽  
Alumina Particles ◽  
Complete Mullitization ◽  
Powder Compacts

Mullite (3Al2O32SiO2) can be fabricated by transient viscous sintering using composite particles which consist of inner cores of a-alumina and outer coatings of amorphous silica. Powder compacts prepared with these particles are sintered to almost full density at relatively low temperatures (~1300°C) and converted to dense, fine-grained mullite at higher temperatures (>1500°C) by reaction between the alumina core and the silica coating. In order to achieve complete mullitization, optimal conditions for coating alumina particles with amorphous silica must be achieved. Formation of amorphous silica can occur in solution (homogeneous nucleation) or on the surface of alumina (heterogeneous nucleation) depending on the degree of supersaturation of the solvent in which the particles are immersed. Successful coating of silica on alumina occurs when heterogeneous nucleation is promoted and homogeneous nucleation is suppressed. Therefore, one key to successful coating is an understanding of the factors such as pH and concentration that control silica nucleation in aqueous solutions. In the current work, we use TEM to determine the optimal conditions of this processing.

Immunocytochemical methodology for the localization of neuronal antigens at the ultrastructural level

1990 ◽  
Vol 48 (3) ◽  
pp. 876-877
Author(s):  
Jorge Pecci Saavedra ◽  
Mark Connaughton ◽  
Juan José López ◽  
Alicia Brusco
Keyword(s):  
Spinal Cord ◽  
Substantia Nigra ◽  
Polyclonal Antibodies ◽  
Ultrastructural Level ◽  
Point Of View ◽  
Nerve Tissue ◽  
Tissue Fixation ◽  
Optimal Conditions ◽  
Interpeduncular Nucleus ◽  
Technical Point

The use of antibodies as labels for the localization of specific molecules in the nervous systan has been extensively applied in recent years. Both monoand polyclonal antibodies or antisera have been employed. The knowledge of the organization of neuronal connectivities, gliovascular relationships, glioneuronal relationships and other features of nerve tissue has greatly increased.A number of areas of the nervous systan have been analyzed in our laboratory, including the nuclei of the raphe system, the reticular formation, interpeduncular nucleus, substantia nigra, caudate nucleus, putamen, pallidum, spinal cord, pineal gland and others.From a technical point of view, a number of variables needed to be taken into account in order to obtain reliable and reproducible results. The design of the optimal conditions of tissue fixation, embedding, sectioning, dilution of antibodies, and adaptation of Sternberger PAP technique were sane of the parameters taken into account to optimize the results. It is critical that each step of the technique be defined for each particular case.

Stability of antioxidant vitamins in whole human blood during overnight storage at 4°C and frozen storage up to 6 months

2018 ◽  
Vol 88 (3-4) ◽  
pp. 151-157 ◽  
Author(s):  
Scott W. Leonard ◽  
Gerd Bobe ◽  
Maret G. Traber
Keyword(s):  
Ascorbic Acid ◽  
Whole Blood ◽  
Healthy Subjects ◽  
Frozen Storage ◽  
Blood Collection ◽  
Plasma Samples ◽  
Optimal Conditions ◽  
Plasma Ascorbic Acid ◽  
Blood Samples ◽  
Sample Handling

Abstract. To determine optimal conditions for blood collection during clinical trials, where sample handling logistics might preclude prompt separation of erythrocytes from plasma, healthy subjects (n=8, 6 M/2F) were recruited and non-fasting blood samples were collected into tubes containing different anticoagulants (ethylenediaminetetra-acetic acid (EDTA), Li-heparin or Na-heparin). We hypothesized that heparin, but not EDTA, would effectively protect plasma tocopherols, ascorbic acid, and vitamin E catabolites (α- and γ-CEHC) from oxidative damage. To test this hypothesis, one set of tubes was processed immediately and plasma samples were stored at −80°C, while the other set was stored at 4°C and processed the following morning (~30 hours) and analyzed, or the samples were analyzed after 6 months of storage. Plasma ascorbic acid, as measured using HPLC with electrochemical detection (LC-ECD) decreased by 75% with overnight storage using EDTA as an anticoagulant, but was unchanged when heparin was used. Neither time prior to processing, nor anticoagulant, had any significant effects upon plasma α- or γ-tocopherols or α- or γ-CEHC concentrations. α- and γ-tocopherol concentrations remained unchanged after 6 months of storage at −80°C, when measured using either LC-ECD or LC/mass spectrometry. Thus, refrigeration of whole blood at 4°C overnight does not change plasma α- or γ-tocopherol concentrations or their catabolites. Ascorbic acid is unstable in whole blood when EDTA is used as an anticoagulant, but when whole blood is collected with heparin, it can be stored overnight and subsequently processed.

Sign in / Sign up

Export Citation Format

Share Document