Discussion of “distribution equilibria of Sn, Se and Tebetween FeO-Fe2O3-SiO2-Al2O33-CuO0.5 slag and metallic copper”

1977 ◽  
Vol 8 (3) ◽  
pp. 695-696 ◽  
Author(s):  
W. J. Rankin
Author(s):  
Gabriel RIVEROS ◽  
Yon-Jin PARK ◽  
Yoichi TAKEDA ◽  
Akira YAZAWA

Polymers ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 401
Author(s):  
Ignacio A. Jessop ◽  
Yasmín P. Pérez ◽  
Andrea Jachura ◽  
Hipólito Nuñez ◽  
Cesar Saldías ◽  
...  

In the search for new materials to fight against antibiotic-resistant bacteria, a hybrid composite from metallic copper nanoparticles (CuNPs) and a novel cationic π-conjugated polyelectrolyte (CPE) were designed, synthesized, and characterized. The CuNPs were prepared by chemical reduction in the presence of CPE, which acts as a stabilizing agent. Spectroscopic analysis and electron microscopy showed the distinctive band of the metallic CuNP surface plasmon and their random distribution on the CPE laminar surface, respectively. Theoretical calculations on CuNP/CPE deposits suggest that the interaction between both materials occurs through polyelectrolyte side chains, with a small contribution of its backbone electron density. The CuNP/CPE composite showed antibacterial activity against Gram-positive (Staphylococcus aureus and Enterococcus faecalis) and Gram-negative (Escherichia coli and Salmonella enteritidis) bacteria, mainly attributed to the CuNPs’ effect and, to a lesser extent, to the cationic CPE.


Friction ◽  
2021 ◽  
Author(s):  
Liangfei Wu ◽  
Zhaozhu Zhang ◽  
Mingming Yang ◽  
Junya Yuan ◽  
Peilong Li ◽  
...  

AbstractRecently, great effort has been devoted to prepare various reinforce fillers to improve polymer performances, but ignoring the importance of raw polymer powders which are indispensable parts of hot-pressed polymer composites. Herein, we engineer raw polyimide (PI) powders with the assistance of polydopamine (PDA) in aqueous solutions. After the modification, polymer powders change from hydrophobic to hydrophilic, which makes it is possible to further modification of polymer powders in liquid phase. During the curing process of modified polymer powders, the partial dehydration of the catechol groups and crosslinking of PDA via C-O-C bonds are confirmed. Based on the features of PDA, a non-destructive mixing method is utilized to realize homogeneous dispersion of multi-walled carbon nanotubes (MWCNTs) in polymer matrix. In comparison with ball milling method, this way can preserve the integrated innate structure of MWCNTs effectively. Besides, by taking full advantage of the reducing and metal-coordination capability of PDA, Cu2+ is successfully loaded onto the surfaces of polymer powders. The related characterizations demonstrate that Cu2+in situ converts to metallic copper rather than copper oxide during the hot pressing process. The tribological properties of corresponding polymer composites are also studied. These results indicate that modifying polymer powders with PDA is multi-profit and presents practical application prospect.


Catalysts ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 1058 ◽  
Author(s):  
Leone Frusteri ◽  
Catia Cannilla ◽  
Serena Todaro ◽  
Francesco Frusteri ◽  
Giuseppe Bonura

Ternary CuxZnyAlz catalysts were prepared using the hydrotalcite (HT) method. The influence of the atomic x:y:z ratio on the physico-chemical and catalytic properties under CO2 hydrogenation conditions was probed. The characterization data of the investigated catalysts were obtained by XRF, XRD, BET, TPR, CO2-TPD, N2O chemisorption, SEM, and TEM techniques. In the “dried” catalyst, the typical structure of a hydrotalcite phase was observed. Although the calcination and subsequent reduction treatments determined a clear loss of the hydrotalcite structure, the pristine phase addressed the achievement of peculiar physico-chemical properties, also affecting the catalytic activity. Textural and surface effects induced by the zinc concentration conferred a very interesting catalyst performance, with a methanol space time yield (STY) higher than that of commercial systems operated under the same experimental conditions. The peculiar behavior of the hydrotalcite-like samples was related to a high dispersion of the active phase, with metallic copper sites homogeneously distributed among the oxide species, thereby ensuring a suitable activation of H2 and CO2 reactants for a superior methanol production.


1980 ◽  
Vol 39 (3-4) ◽  
pp. 417-450 ◽  
Author(s):  
G. J. Ehnholm ◽  
J. P. Ekstr�m ◽  
J. F. Jacquinot ◽  
M. T. Loponen ◽  
O. V. Lounasmaa ◽  
...  
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