A new graphene-based transistor in which electrons travel both over a barrier and under it (by tunneling) has exhibited one of the highest performances of graphene-based transistors to date.
 
The combination of the two types of transport enables the transistor to achieve a large difference between its on and off states, giving it a high on/off ratio, which has so far been difficult to achieve in graphene-based transistors. With this advantage, in addition to its ability to operate on transparent and flexible substrates, the new transistor could play a role in post-CMOS devices that are expected to be able to compute at much faster speeds than today's devices.

The researchers from the University of Manchester in the UK, who designed the new graphene-based transistor, have published their study on the device in a recent issue of Nature Nanotechnology.

As the researchers explain in their study, other graphene-based transistors have previously been demonstrated, many of which have a sandwich structure with atom-thick sheets of graphene forming the outer layers and a different ultrathin material forming the middle layer. This middle layer can consist of many possible materials. In the current study, the researchers used two-dimensional tungsten disulphide (WS2) as the middle layer, which served as an atomically thin barrier between the two layers of graphene.

The biggest advantage of using WS2 compared to most other barrier materials is that WS2's chemical properties allow electrons to cross either by going over the barrier, as in thermionic transport, or under it, as in tunneling. In the off state, very few electrons can cross the barrier by either transport method, but they can cross by one or both methods in the on state.

Switching between the two states involves changing the transistor's gate voltage. A negative gate voltage creates the off state, since it increases the tunneling barrier height so that few electrons can cross the barrier. A positive gate voltage switches the transistor to the on state by reducing the tunneling barrier height and—if the temperature is high enough—allowing over-barrier thermionic current as well.

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HOUSTON, TX -- 01/22/13 -- Vantage Drilling Company ("Vantage")  announces today that it has received a conditional letter of award for its newbuild drillship the Tungsten Explorer to work in West Africa. The award is for a period of up to four years commencing in mid 2014.

The contract has a minimum duration of two years, while the customer has four six-month options to extend the contract. The letter of award is subject to customary conditions including negotiating the final terms of the contract which is anticipated to be completed in the first quarter 2013. The estimated revenue over the initial two year firm period of the contract is approximately $468 million, including mobilization.

What topics should CFOs get their arms around so they won't seem out of touch at board meetings this year?

As a CFO, you’re probably not a member of the company’s board. But you might as well be. You attend the greater portion of most board meetings and are asked for a lot of input.

But are you always fully prepared? After all, a new hot item may pique the board’s interest at any time.

Conflict Minerals
It’s just one of the 398 rulemakings required by the Dodd-Frank Act (and one of 136 that have been finalized). But the Securities and Exchange Commission’s new regulations regarding “contract minerals” promise to be prominent in boardroom discussions this year and perhaps next.

The SEC estimates that about 6,000 U.S. companies, or 40% of the­ approximately 15,000 publicly held ones, will be subject to heavy new compliance requirements. That is, any company that sells products containing gold, tantalum, tin, or tungsten, or otherwise uses those substances in making products, must publicly report on the metals’ movement through its supply chain. The purpose is to determine whether they were mined in the Democratic Republic of Congo and surrounding countries, where warring parties have been looting mines for years and selling the four metals in the global market to fund their violent activities.

The reporting requirement begins in May 2014. But companies’ initial reports must cover calendar-year 2013 supply-chain activities. Reports containing false or misleading statements could expose CFOs to liability under securities laws.

Most public companies in the aerospace, automotive, construction, electronics, industrial equipment and tools, jewelry, and medical equipment industries will be subject to the rules. Privately held companies could be at risk as well, if they supply products to public companies. In the aggregate, companies will spend several billion dollars to comply with the regulations, says Dennis Whalen, executive director of KPMG’s Audit Committee Institute.

“It’s going to be an awful lot of work for companies,” says Richstone, noting that the matter did not get on many boards’ radar screens until fairly recently.

At a board meeting where she first heard about it, “we all sat there with our mouths hanging open, saying is this for real?”

Several lobbying initiatives funded by corporations are under way in Washington over the issue, most notably one spearheaded by the Direct Marketing Association, Friedman notes.

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W Resources expects the La Parrilla tailings project to be in production in the second half of 2013 - after it received final approval.

The regional authority of the Junta de Extremadura has given the go-ahead for the project in Spain, the firm told investors.

Annual plant feed is expected to be around 330,000 tonnes and annual production anticipated to be 28,000 MTU (metric ton unit) of tungsten and 26 tonnes of tin.