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As of 2020, the most expensive non- synthetic element by both mass and volume is rhodium. It is followed by caesium, iridium and palladium by mass and iridium, gold and platinum by volume. Carbon in the form of diamond can be more expensive than rhodium. Per-kilogram prices of some synthetic radioisotopes range to trillions of dollars.
Tencent QQ (Chinese: 腾讯QQ), also known as QQ, is an instant messaging software service and web portal developed by the Chinese technology company Tencent. QQ offers services that provide online social games, music, shopping, microblogging, movies, and group and voice chat software. As of March 2023, there were 597 million monthly active QQ ...
The General Electric Catalyst (formerly Advanced Turboprop, or ATP) is a turboprop engine by GE Aerospace. It was announced on 16 November 2015 and will power the Beechcraft Denali, it first ran on December 22, 2017, and should be certified in 2024. The 850 to 1,600 hp (630 to 1,190 kW) engine aims for 20% better efficiency than its competition ...
Heterogeneous gold catalysis. Model structure of a 75-atom two-layer gold cluster with a diameter of roughly 2 nm deposited on a rutile TiO 2 (110) surface. Yellow, gray and red spheres depict gold, titanium and oxygen atoms, respectively. The structure has not been optimized computationally, and thus serves only as a conceptual illustration.
Lewis acid catalysis. In Lewis acid catalysis of organic reactions, a metal-based Lewis acid acts as an electron pair acceptor to increase the reactivity of a substrate. Common Lewis acid catalysts are based on main group metals such as aluminum, boron, silicon, and tin, as well as many early (titanium, zirconium) and late (iron, copper, zinc ...
Selective catalytic reduction. CATALYTIC REDUCTION. Selective catalytic reduction (SCR) means of converting nitrogen oxides, also referred to as NO. x with the aid of a catalyst into diatomic nitrogen (N. 2), and water (H. 2O). A reductant, typically anhydrous ammonia (NH. 3), aqueous ammonia (NH. 4OH), or a urea (CO (NH.
The catalyst also demonstrated a volumetric activity of 230 A·cm −3, the highest value for non-PGM catalysts to date, [44] approaching the U.S. Department of Energy milestone. While the power density achieved by the novel FeAc/Phen/ZIF-8-catalyst is promising, its durability remains inadequate for commercial application.
The Cisco Catalyst 4500 Series is a mid-range modular chassis network switch. The system comprises a chassis, power supplies, one or two supervisors, line cards and service modules. The Series includes the E-Series chassis and the Classic chassis which is manufactured in four sizes: ten-, seven-, six-, and three-slot.