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Polymers ◽  
2021 ◽  
Vol 13 (22) ◽  
pp. 4013
Author(s):  
Jui-Teng Lin ◽  
Jacques Lalevee ◽  
Hsia-Wei Liu

This article presents, for the first time, the kinetics and the general features of a photopolymerization system (under visible light), copper-complex/Iodonium/triethylamine/gold-chloride (orA/B/N/G), with initial concentrations of A0, B0, N0 and G0, based on the proposed mechanism of Tar et al. Analytic formulas were developed to explore the new features, including: (i) both free radical photopolymerization (FRP) efficacy and the production of nanogold (NG), which are proportional to the relative concentration ratios of (A0 + B0 + N0)/G0 and may be optimized for maximum efficacy; (ii) the two competing procedures of NG production and the efficacy of FRP, which can be tailored for an optimal system with nanogold in the polymer matrix; (iii) the FRP efficacy, which is contributed by three components given by the excited state of copper complex (T), and the radicals (R and S) produced by iodonium and amine, respectively; (iv) NG production, which is contributed by the coupling of T and radical (S) with gold ion; and (v) NG production, which has a transient state proportional to the light intensity and the concentration ratio A0/G0) + (N0/(K’M0), but also a steady-state independent of the light intensity.


Author(s):  
Jui-Teng Lin ◽  
Jacques Lalevee ◽  
Haja Tar ◽  
Da-Chun Cheng

. This article presents, for the first time, the kinetics and the general features of a photopolymerization system (under visible light) G1/ Iodonium/ TEA/gold chloride (or A/B/N/G), having initial concentrations of A0, B0, N0 and G0, based on the proposed mechanism of Tar et al. Analytic formulas are developed to explore the new features including: (i) both FRP efficacy and the production of nanogold (NG) are proportional to the relative concentration ratios of (A0+B0+N0)/G0, which may be optimized for maximum efficacy; (ii) the two competing procedure of NG production and efficacy of free radical photopolymerization (FRP) can be tailored for optimal system with nanogold in the polymer matrix;(ii) the FRP efficacy is contributed by 3 components: the coupling of the excited state of copper complex (T) with the radicals (R and S) produced by the iodonium and the amine; (iii) the production of NG is contributed by 2 components: the coupling of T and radical (S) with gold ion; (iv) NG production has a transient state value which is an increasing function of light intensity and the combined concentration ratio [(A0/G0)+(N0/(K'M0). whereas it has a steady-state independent to the light intensity.


Author(s):  
Lyutsiya M. Karimova ◽  
Dmitry V. Zakharyan ◽  
Yaroslav E. Agapitov

Laboratory studies have been carried out on the processing of gold-bearing concentrate from the “Jamgyr” deposit using the JIN CHAN reagent. The influence of the concentration JIN CHAN, the duration of leaching, the temperature of the solution were studied. As a result of research, the extraction of gold and silver into solution using cyanide-free technology was 97,5% and 96%, respectively. The processing of the obtained solutions by the method of sorption was carried out on the MA940BG (gold) ion-exchange resin with the extraction of target components from the solution into the ion-exchange resin: Au – 100,0%, Ag – 77,5%


2021 ◽  
Author(s):  
Makoto Ozaki ◽  
Shuhei Yoshida ◽  
Takaaki Tsuruoka ◽  
Kenji Usui

Our method can produce uniquely shaped gold nanostructures in lower HAuCl4 concentration than conventional methods by intracellular functions using peptide assembled structures as a template.


Vacuum ◽  
2020 ◽  
Vol 182 ◽  
pp. 109700
Author(s):  
Pankaj Singh Rawat ◽  
R.C. Srivastava ◽  
Gagan Dixit ◽  
K. Asokan

Crystals ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 382
Author(s):  
Cornelia M. Schneider ◽  
Helmut Cölfen

Gold nanoclusters consisting of a specific atom number have gained popularity in research in recent years due to their outstanding properties. Due to their molecule-like behavior, their properties depend strongly on their size. Although they represent the link species between atoms and nanoparticles and are the subject of current research, a high-resolution characterization is still missing. Here, we used the band forming experiment in analytical ultracentrifugation (AUC) to characterize the gold nanoclusters in the moment of their generation using thioglycerol as a stabilizer. The concentration variation of the gold precursor, reducing agent, and stabilizer was investigated. The formation of different cluster species from the smallest Au4 up to Au911 could be observed. Very stable clusters of Au55 appear in every experiment and other cluster sizes more rarely. The extracted UV/Vis spectra could additionally be correlated to every cluster. The variation in the concentration of sodium borohydride and the stabilizer did not lead to a clear trend, but the gold ion concentration directed the size of the formed clusters. A decrease seemed to promote the generation of a higher abundance of smaller clusters accompanied by less big clusters, and vice versa. These results present the characterization of the different nanocluster generations directly in the formation process of nanoparticles and therefore are a contribution to the understanding of their formation.


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