Paper-thin gallium oxide transistor handles more than 8,000 volts
People love their electric cars. But not so much the bulky batteries and related power systems that take up precious cargo space.
May 29, 2020
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215
Electronics & Semiconductors
People love their electric cars. But not so much the bulky batteries and related power systems that take up precious cargo space.
May 29, 2020
3
215
Energy & Green Tech
The world's largest all-electric plane has successfully completed a test flight, the first step in a long process its developers say will led to an era of low-cost, pollution-free air travel.
Engineering
Large telescopes that could be used for detecting and analyzing Earth-like planets in orbit around other stars or for peering back in time to observe the very early universe may not necessarily have to be built and assembled ...
May 8, 2020
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24
Electronics & Semiconductors
A new supercapacitor based on manganese oxide could combine the storage capacity of batteries with the high power and fast charging of other supercapacitors, according to researchers at Penn State and two universities in ...
May 5, 2020
1
317
Energy & Green Tech
Electrical energy derived from renewable sources could be used to rearrange bonds in carbon dioxide (CO2) and water molecules into complex hydrocarbons, which can then be burnt to produce new energy and CO2, ultimately enabling ...
Energy & Green Tech
Solid oxide fuel cells, or SOFCs, are devices that produce both electricity and heat by oxidizing a fuel such as natural gas or biogas. This energy-efficient, zero-emission technology has the potential to meet domestic and ...
Feb 28, 2020
1
288
Energy & Green Tech
Across Europe's cities, the demand for delivery services is increasing. But these deliveries affect urban life as they add to traffic congestion, noise and pollution and many cities are now trying out alternative modes of ...
Feb 10, 2020
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26
Electronics & Semiconductors
At the heart of any electronic device is a cold, hard computer chip, covered in a miniature city of transistors and other semiconducting elements. Because computer chips are rigid, the electronic devices that they power, ...
Feb 6, 2020
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15
Hardware
A through-the-wall radar, built on a chip smaller than a grain of rice, has been developed by a team of researchers at the Indian Institute of Science (IISc), led by Gaurab Banerjee, Associate Professor at the Department ...
Jan 28, 2020
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24
Engineering
Metal oxide thin-film transistors (TFTs), which are built by depositing thin films of an active metal oxide-based semiconducting material on a supporting substrate, have become widely used over the past few years, particularly ...
An oxide ( /ˈɒksaɪd/) is a chemical compound that contains at least one oxygen atom in its chemical formula. Metal oxides typically contain an anion of oxygen in the oxidation state of −2.
Most of the Earth's crust consists of solid oxides. Oxides result when elements are oxidized by oxygen in air. Combustion of hydrocarbons affords the two principal oxides of carbon, carbon monoxide and carbon dioxide. Even materials that are considered to be pure elements often contain a coating of oxides. For example, aluminium foil has a thin skin of Al2O3 that protects the foil from further corrosion.
Virtually all elements burn in an atmosphere of oxygen, or an oxygen rich environment. In the presence of water and oxygen (or simply air), some elements—lithium, sodium, potassium, rubidium, caesium, strontium and barium—react rapidly, even dangerously, to give the hydroxides. In part for this reason, alkali and alkaline earth metals are not found in nature in their metallic, i.e., native, form. Caesium is so reactive with oxygen that it is used as a getter in vacuum tubes, and solutions of potassium and sodium, so called NaK are used to deoxygenate and dehydrate some organic solvents. The surface of most metals consists of oxides and hydroxides in the presence of air. A well known example is aluminium foil, which is coated with a thin film of aluminium oxide that passivates the metal, slowing further corrosion. The aluminium oxide layer can be built to greater thickness by the process of electrolytic anodising. Although solid magnesium and aluminium react slowly with oxygen at STP, they, like most metals, will burn in air, generating very high temperatures. Finely grained powders of most metals can be dangerously explosive in air. Consequently, they are often used in Solid-fuel rockets.
In dry oxygen, iron readily forms iron(II) oxide, but the formation of the hydrated ferric oxides, Fe2O3−2x(OH)x, that mainly comprise rust, typically requires oxygen and water. The production of free oxygen by photosynthetic bacteria some 3.5 billion years ago precipitated iron out of solution in the oceans as Fe2O3 in the economically important iron ore hematite.
Due to its electronegativity, oxygen forms chemical bonds with almost all elements to give the corresponding oxides. Noble metals (such as gold or platinum) resist direct chemical combination with oxygen, and substances like gold(III) oxide must be generated by indirect routes.
This text uses material from Wikipedia, licensed under CC BY-SA