China 
Africa 
Explore chapters and articles related to this topic
Radiochemical Activation Analysis by Accelerated Charged Particles
Published in Zeev B. Alfassi, Max Peisach, Elemental Analysis by Particle Accelerators, 2020
Vandecasteele and Hoste38 determined oxygen in germanium by distillation followed by PbClF precipitation, while Schweikert et al.43 separated the matrix by precipitation of germanium hydroxide (by addition of ammonia solution). As and Se, formed from germanium upon irradiation, were removed as silver arsenide and silver selenide by drop wise addition of 5 M HNO3. This precipitation was repeated, with extra amounts of carriers of As and Se. After removal of the matrix and the main element formed from it, 18F was further decontaminated by steam distillation of fluorosilic acid from phosphoric acid. However this process suffers from the disadvantage that the final sample for counting is of 125 mL. Better measurements of counting will be obtained by precipitation of the 18F.
Synthesis of Zinc, Copper, Cadmium, and Iron Sulfides and Their Sorption Properties
Published in D.S. Sofronov, K.N. Belikov, M. Rucki, S.N. Lavrynenko, Z. Siemiątkowski, E. Yu. Bryleva, O.M. Odnovolova, Synthetic Sorbent Materials Based on Metal Sulphides and Oxides, 2020
D.S. Sofronov, K.N. Belikov, M. Rucki, S.N. Lavrynenko, Z. Siemiątkowski, E. Yu. Bryleva, O.M. Odnovolova
Investigation of the synthesis conditions effect on the zinc sulfide particles formation leads to the interesting observation. When the aqueous ammonia solution serving as an alkaline reagent was replaced by sodium hydroxide or potassium hydroxide, diameter of spherical particles substantially decreased. That fact is very important for the further investigation of the particle dimensions impact on fundamental absorption edge in cadmium sulfide, especially in case of optical materials production. In order to examine the aforementioned effect, chloride solutions were chosen, because they produced the particles with minimal dimensions and maximal yield.
Comparison of the Results of Different Adhesion Tests Carried Out on Hot-Dip Galvanised Steel
Published in L. Fedrizzi, P. L. Bonora, Organic and Inorganic Coatings for Corrosion Prevention – Research and Experiences, 2019
The adhesion to galvanised steel pretreated by the ammonia solution showed high values when thorough rinsing was used. If a small quantity of water was used (slight rinsing) the adhesion values were low. This results proves, that the quantity of water during rinsing is of great importance for the interface adhesion. There are no publications at all on this pretreatment method and the possible chemical reactions between the ammonia solution and the zinc surface. Therefore, the present authors can only speculate on a causal connection between adhesion and the quality of rinsing after treating with ammonia solution. On the one hand, it is well known that hot dip galvanised zinc coatings form zinc oxide and zinc hydroxide on their surfaces immediately after galvanising. On the other hand, water soluble zinc di- or tetraammine hydroxide can be formed as a result of the reaction between zinc hydroxide and ammonia solution. By rinsing the zinc surface thoroughly after treating it with ammonia solution these soluble products were removed. In the case of slight rinsing these soluble compounds can remain on the zinc surface and lead to lower adhesion of the painted zinc coating.
Selective glycerol oxidation to glyceric acid under mild conditions using Pt/CeO2–ZrO2–Fe2O3/SBA-16 catalysts
Published in Journal of Asian Ceramic Societies, 2022
Yeon-Bin Choi, Naoyoshi Nunotani, Kunimitsu Morita, Nobuhito Imanaka
Mesoporous silica SBA-16 was prepared according to a method reported elsewhere [28]. Pluronic F-127 (Sigma-Aldrich) (1.6 g) as a nonionic surfactant and 1,3,5-trimethylbenzene (Kishida Chemical, ≥ 98.0%) (1.1 mL) as a swelling agent were dissolved in 90 mL of 0.2 mol·L−1 hydrochloric acid, which was prepared by diluting concentrated hydrochloric acid (Kishida Chemical, 35%) with deionized water. Tetraethoxysilane (Kishida Chemical, ≥ 99.0%) (7.1 mL) was added to the solution and stirred at 35°C for 24 h, followed by hydrothermal treatment at 140°C for 24 h using a Teflon bottle in a sealed brass vessel. The precipitates formed were collected by suction filtration, washed with deionized water and ethanol, dried at 80°C for 12 h, and finally calcined at 600°C for 4 h under a flow of air (15 mL·min−1). Ce0.64Zr0.16Fe0.20O2−δ/SBA-16 was synthesized using a co-precipitation technique. Solutions of 1.0 mol·L−1 Ce(NO3)3, 0.10 mol·L−1 ZrO(NO3)2, and 0.10 mol·L−1 Fe(NO3)3 were prepared by dissolving Ce(NO3)3 · 6H2O (Kojundo, 99.9%), ZrO(NO3)2 · 2H2O (Kishida Chemical, ≥ 99.0%), and Fe(NO3)3∙9H2O (FUJIFILM Wako Pure Chemical, 99.9%) in deionized water, respectively. The SBA-16 powder (0.4 g) was dispersed in a 1.0 mol·L−1 Ce(NO3)3 aq., 0.10 mol·L−1 ZrO(NO3)2 aq., and 0.10 mol·L−1 Fe(NO3)3 aq. in the stoichiometric ratio, followed by the addition of 30 mL of deionized water. After stirring at room temperature for 30 min, an aqueous solution of ammonia (5vol%), prepared by diluting ammonia solution (Kishida Chemical, 28%) with deionized water, was added dropwise into the solution with vigorous stirring until pH = 11. This was followed by further stirring at room temperature for 12 h. The precipitates were filtered by suction filtration, dried at 80°C for 12 h, and then calcined at 900°C for 1 h in atmospheric air. The Ce0.64Zr0.16Fe0.20O2−δ loading amount (x) varied from 0 to 60 wt%, and the samples were denoted as xwt%CZFe/SBA. Pt loading onto xwt%CZFe/SBA was carried out by the impregnation method. The xwt%CZFe/SBA powder (0.4 g) was suspended on a platinum colloid stabilized with polyvinylpyrrolidone (Pt: 4.0wt%; Tanaka Kikinzoku Kogyo) and 40 mL of ethanol (Kishida Chemical, 99.5%) was added, where the Pt amount was adjusted to 7 wt%. The solution was evaporated at 90°C for 2 h, and the resulting powder was calcined at 500°C for 4 h in atmospheric air. Hereafter, 7 wt%Pt/xwt%Ce0.64Zr0.16Fe0.20O2−δ/SBA-16 are represented as Pt/xwt%CZFe/SBA.