schumann@puff.UUCP (02/17/87)
This morning (Tuesday), I saw a small story on Headline News about some scientist at a Houston University (I think) that has made a great advancement in the practicality of superconducters. Well, What's the scoop? What did he do, how will it affect *us*, and what should be known, etc, etc.... Chris Schumann schumann@puff.wisc.edu
dplatt@teknowledge-vaxc.UUCP (02/18/87)
Based on what I saw in the San Jose Mercury-News, a research team has developed an alloy which begins exhibiting superconducting behavior at an extremely high temperature (well above the boiling-point of liquid helium, and well below the boiling point of liquid nitrogen) at "normal" pressures. If I've got these details correctly, then it is indeed a major breakthrough... all previous "high"-temperature semiconductors have required extremely high pressures to operate (e.g. several thousand or million PSI), and none have switched to semiconducting behavior at liquid-nitrogen temperatures. In short, it means that semiconductive circuits (e.g. magnetic-levitation systems) can now be refrigerated with liquid nitrogen, which is MUCH cheaper and easier to handle than liquid helium. This should increase the practical use of semiconductors in maglev systems, power-generation, lasers, etc. by an order of magnitude.
ch@well.UUCP (02/19/87)
In article <503@puff.WISC.EDU> schumann@puff.WISC.EDU (Christopher Schumann) writes: >This morning (Tuesday), I saw a small story on Headline News about some >scientist at a Houston University (I think) that has made a great >advancement in the practicality of superconducters. What you are referring to, I believe, is detailed in Science magazine, Vol. 235, 30 January, 1987. There are two seperate articles, pp. 531, and 567. Briefly, the article details the research of several independent teams who have reportedly observed the onset of superconductivity at temperatures as high as 70 degrees Kelvin. The Houston team has observed an onset temperature of 52 degrees Kelvin in a material that became fully superconductive at 25 K. The material used was a lathanum-barium-copper-oxygen compound under hydrostatic pressure. Scientifically, these findings are notable because they seem to indicate that superconductivity may be possible at at temperatures higher than those predicted by previous theories. Practically, the availability of inexpensive materials that superconduct at much higher temperatures than previously known materials will key the development of motors, coils, magnets, etc., of unprecedented efficiency, size, and power. -- Chris Hayes UUCP: ucbvax!dual!well!ch OR : {hplabs, ptsfa, lll-lcc}!well!ch
haddock@ti-csl.UUCP (02/19/87)
In article <503@puff.WISC.EDU> schumann@puff.WISC.EDU (Christopher Schumann) writes: >This morning (Tuesday), I saw a small story on Headline News about some >scientist at a Houston University (I think) that has made a great >advancement in the practicality of superconducters. > >Well, What's the scoop? What did he do, how will it affect *us*, and >what should be known, etc, etc.... > I heard the same thing on one of the local radidio stations here. I was still half asleep so the numbers are probably wrong but.... It appears that the researchers have found a way to have superconductance at relatively "high" temperatures. What they meant by "high" is they've found a way to use "cheap" liquid nitrogen to acheive superconductance. The great idea behind this is that liquid nitrogren is about 10X cheaper than the liquid helium(?) and superconductance is attained at 20X the temperature. No immediate benefits (for the public) are perceived but with more research hopefully a more efficient means of transmitting electrical energy will be found via the use of superconductance. -Rusty- -- ================================================================ Rusty Haddock +++ Texas Instruments, Inc. +++ Dallas, Texas Computer Science Center, CRD&E +++ CSNET: Haddock@TI-CSL USENET: {ut-sally!im4u,convex!smu,sun!texsun}!ti-csl!haddock
daveh@cbmvax.UUCP (02/19/87)
> In-reply-to: schumann@puff.WISC.EDU's message of 17 Feb 87 19:27:10 GMT > > Based on what I saw in the San Jose Mercury-News, a research team has > developed an alloy which begins exhibiting superconducting behavior at > an extremely high temperature (well above the boiling-point of liquid > helium, and well below the boiling point of liquid nitrogen) at > "normal" pressures. I never saw the article, but about a month ago a friend who works with superconducting magnets at MIT mentioned such a breakthough. The new superconducting material will superconduct at around 40K, and its probably going to be much cheaper to make than the previous record holder, which superconducts at around 20K. Because of the cost of the 20K superconductor, they've done little to no magnetics research with it, they're still well into liquid He and occasionally He3. -- ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Dave Haynie {caip,ihnp4,allegra,seismo}!cbmvax!daveh You too can put the POWER of RANDOM NUMBERS to work for you! ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
jewett@hpl-opus.UUCP (02/19/87)
A recent New York Times article (in the SF Cronicle) says that Chu and Wu (Univ. Houston and Univ. Alabama resp.) have reported supercondutivity at -283F which is 98 kelvins. Their work is to be reported soon in Phys. Rev. Lett. The latest Scientific American reported that the 70K claim from China had been withdrawn.
piner@pur-phy.UUCP (02/22/87)
In article <1439@cbmvax.cbmvax.cbm.UUCP> daveh@cbmvax.cbm.UUCP (Dave Haynie) writes: >> In-reply-to: schumann@puff.WISC.EDU's message of 17 Feb 87 19:27:10 GMT >> developed an alloy which begins exhibiting superconducting behavior at >> an extremely high temperature (well above the boiling-point of liquid >> helium, and well below the boiling point of liquid nitrogen) at >> "normal" pressures. >superconducting magnets at MIT mentioned such a breakthough. The new >superconducting material will superconduct at around 40K, and its >probably going to be much cheaper to make than the previous record >holder, which superconducts at around 20K. Because of the cost of the >20K superconductor, they've done little to no magnetics research with it, >they're still well into liquid He and occasionally He3. >-- This is old news. Things are happening very fast right now. The latest superconductor transition is around 90K, well above liquid N2. Rumor has it that a 150K transition has been seen. Rumor also has it that a "dry ice" superconductor may be possible. There is a rub however. These materials are oxides. No one knows how to make a wire out of them. Yet. Richard Piner piner@galileo.physics.purdue.edu
witters@fluke.UUCP (02/24/87)
Does anyone else remember an article some years back in Electronics about a possible room temperature superconductor? Apparently someone used a 4 terminal Ohm meter to measure the resistance of some titanium alloy they were trying to make ductile, and it indicated zero resistance. However, this is only one characteristic of a true superconductor, and the article said that further experiments would have to be done to determine if the material would repel a magnetic field. I never saw a followup article. If I remember correctly, the article appeared sometime in 1979 or 1980. Since I haven't seen anything more about this, I can think of three possibilities. 1. The experiments were performed, and it turned out that the material wasn't a superconductor. It seems to me that if this was the case, there would have been a followup article. 2. The NSA classified the research. If I remember correctly, the research was originally being done for the Air Force (titanium, remember?), so it would be easy for the stuff to get classified. 3. The article appeared in the April issue. If so, I think there should have been a followup revealing the article as a prank. -- I'm not a lumberjack and I'm not O.K. John Witters (206) 356-5274 John Fluke Mfg. Co. Inc. cryptography DES drugs cipher NSA CIA DIA P.O.B. C9090 M/S 245F NRO IRS coke crack missile atom Libyan RSA Everett, Washington 98206