نتایج جستجو برای: precious metal

تعداد نتایج: 201716  

2008
Yu-Lung Lam Kwong-Yu Chan Patrick H. Toy Chong Yuet Ming

Polystyrene-grafted-polyglycidol (PS-PG), a water-compatible resin, is applied for the extraction of precious metal in effluents of electroplating process. The extractions of gold (I) and silver (I) cyanide using this resin are investigated. More than 99% of gold and 99% of silver ions of the originally dissolved could be extracted from the aqueous phase to polymer phase. Recycling of the resin...

2016
Saravanakumar Elangovan Jacob Neumann Jean-Baptiste Sortais Kathrin Junge Christophe Darcel Matthias Beller

Borrowing hydrogen (or hydrogen autotransfer) reactions represent straightforward and sustainable C-N bond-forming processes. In general, precious metal-based catalysts are employed for this effective transformation. In recent years, the use of earth abundant and cheap non-noble metal catalysts for this process attracted considerable attention in the scientific community. Here we show that the ...

Journal: :Dental materials journal 1998
H Ohno Y Yamane K Endo Y Araki Y Iizuka

New dental precious metal alloys for resin bonding without alloy surface modification were developed by adding base metals (In, Zn, or Sn). Before this, binary alloys of Au, Ag, Cu, or Pd containing In, Zn, or Sn were studied for water durability and bonding strength with 4-META resin. The adhesion ability of the binary alloys was improved by adding In equivalent to 15% of Au content, Zn equiva...

Journal: :Journal of Material Cycles and Waste Management 2019

2008
Walter Scheidel

The Chinese tradition of supplementing large quantities of bronze cash with unminted gold and silver represents a rare exception to the western model of precious-metal coinage. This paper provides a detailed discussion of monetary development in ancient China followed by a brief survey of conditions in the Roman empire. The divergent development of the monetary systems of the Han and Roman empi...

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