The day after - No-17/ 04-11-22 18:33:12
|Dr inż. Hieronim Piotr Janecki email@example.com|
|Current topic Issues from Nanoscale and Macro scale Materials|
Dla przybliżenia Państwu zagadnień związanych z nowymi technikami laboratoryjnymi, nanoskalą /mikroskalą
i problemami etyki oraz dobrymi obyczajami w nauce pozwolę sobie przytoczyć poniżej fragment pewnej dyskusji, która odbywa się aktualnie w Świecie Nauki w USA. Problem dotyczy organicznych laserów wysokotemperaturowych opracowanych przez mojego kolegę ze studiów w Politechnice Śląskiej Dr Christiana Kloca. Wczoraj wysłałem list do USA z zapytaniem co sądzi o dołączeniu publikacji o nim do naszej strony, oto odpowiedź Pana Doktora Christiana Kloca.
To concern you with the problems connecting with new laboratory techniques e.g. Nanoscale/micro scale and good jobs in science and searching area. I will try to show you an example discussion from the Science World of USA Today. The Problem is concerned with so called high temperature organic lasers co created from Dr Christian Kloc Yesterday I send an @ to him with the Question and proposal to link his works to my Website. That is what Dr Christian Kloc answered to me. ( The letter in Polish and linked comments in English )
Użytkownik Christian Kloc <firstname.lastname@example.org> napisał:
>chyba zly czas wybrales na te informacje. Jesli chcesz doloz to co
>zalanczam Ci z teraz. A to dopiero poczatek polowania na czarownice i ja
>nie wiem, tak jak wszyscy inni, czy moj kolega jest taki genialny czy
A Sudden Host of Questions on Bell Labs Breakthroughs
n a ski slope in Utah in March, Paul Grant and Rick Greene made a bet — about superconductors.
Dr. Grant and Dr. Greene, who had been longtime colleagues at the
Dr. Grant doubts the findings. Dr. Greene said he thought that they they would be verified.
Last week, Dr. Grant sent an e-mail message reminding Dr. Greene of
the wager, because the lead researcher of the experiment was Dr. J.
Hendrik Schön, the Bell Labs scientist who is now the center of a
scientific misconduct investigation. Nearly identical graphs appear in
several of Dr. Schön's scientific papers, even though the graphs
represent different data from different experiments. Bell Labs, part of
But even before the two main papers cited in the investigation were published, a debate had arisen over the superconductor claims.
"There's been a lot of buzz for well over a year," said Dr. Grant, now a science fellow at the Electric Power Research Institute in Palo Alto, Calif.
Dr. Schön and his collaborators have developed a revolutionary technique that allows them to explore systematically the electronic properties of various materials. Dr. Grant had called the team's "buckyball" work paper "a tour de force of physics" when it was announced. Other scientists said it might be worthy of a Nobel Prize.
The superconductor work is not among the seven papers that include the suspect graphs, which report advances in organic transistors and molecular electronics. But the investigation casts a pall over all of Dr. Schön's research. He has been an author on more than 70 scientific papers in the last two and a half years — a remarkably prodigious output — and some people wonder whether there might be undiscovered problems with other papers.
"That has to be the question on everybody's minds," said Dr. Arthur Hebard, a professor of physics at the University of Florida and a former Bell Labs scientist. "I have more skepticism about the data."
Dr. Schön's collaborators on the superconductor work — Dr. Christian Kloc, a chemist at Bell Labs, and Dr. Bertram Batlogg, ex-director of solid state physics research at Bell Labs and now a professor of physics at the Swiss Federal Institute of Technology in Zurich — are also co-authors of several of the questioned papers. Some researchers are increasingly disturbed that no one has reproduced the superconducting results since they were reported a year and a half ago.
"Good stuff will repeat itself in other laboratories," Dr. Hebard said.
Dr. Schön has declined to comment on the questions about his work other than that he stands by his results and that he will cooperate with the panel. Dr. Kloc also declined to comment, and efforts to reach Dr. Batlogg have been unsuccessful.
Bell Labs officials have said that the panel will investigate those questions and that Lucent will act on its recommendations.
Dr. Hebard was on a Bell Labs team that discovered in 1991 that buckyballs, molecules made of 60 carbon atoms arrayed in the shape of a soccer ball, could be turned into superconductors when mixed with potassium, a process that adds electrons to carry the electrical current. Buckyballs are named after R. Buckminster Fuller, designer of the geodesic dome that they resemble.
But the buckyballs switched back into insulators at temperatures above minus 427 degrees Fahrenheit. Other researchers verified that work. But because so-called high-temperature superconductors work at considerably warmer temperatures, most researchers in the field soon lost interest.
The new team at Bell Labs, Drs. Schön, Kloc and Batlogg, took a radically different approach to making buckyball superconductors. In Nature on Nov. 30, 2000, the researchers reported that they had essentially built a transistor out of buckyballs. They placed a layer of aluminum oxide on top a neatly stacked crystal of buckyballs and then gold electrodes on the aluminum oxide.
The electrodes, the team reported, generated an electric field strong enough to yank an average of three electrons away from each buckyball. The "holes" left behind by the missing electrons were then able to condense into a superconducting current. The electron-depleted buckyballs were superconducting up to a temperature of minus 366 degrees, the scientists said.
In the paper, they also wrote that calculations indicated that if the buckyballs could be moved farther apart from one another, the superconducting temperature could be pushed up even more.
A year later, they reported in Science that they had achieved just that. By wedging bromoform, a molecule containing bromine, between the buckyballs, the team said it had raised the superconducting temperature to minus 249 degrees, warmer than most high-temperature superconductors.
But scientists who tried to reproduce the experiment have been stymied at the first step of the first experiment, making the layer of aluminum oxide, which acts as an insulator to prevent electric charge on the gold electrodes from arcing across to the buckyballs.
Because buckyballs hold their electrons tightly, pulling off one electron requires a strong electric field. Pulling three off requires a very strong electric field. But for everyone else, the oxide layer failed at electric fields far weaker than those reported in the Bell Labs papers.
"We're off almost by a factor of 10," Dr. Hebard said, adding that it was possible that the Bell Labs researchers used special techniques not yet discovered by others.
"If it's correct," Dr. Hebard said, "it's a wonderful challenge. If it's not correct, it's very troubling."
Dr. Arthur P. Ramirez, a scientist at the Lawrence Livermore National Laboratory who was on the 1991 team that discovered buckyball superconductivity, said he believed that the researchers had achieved what they claimed — superconducting buckyballs at minus 249 degrees. "It seems to hold together with previous work we did," he said.
Dr. Ramirez has also come closest to reproducing the work.
Using buckyball crystals provided by Dr. Kloc, Dr. Ramirez has produced transistors with aluminum oxide layers that withstand electric fields three times as strong as Dr. Hebard's, although it still needs to be three times as great as it is now to achieve superconductivity.
"It requires a combination of different expertises that is not commonly found in one place," Dr. Ramirez said. "We've been working on this for half a year, and it's pretty difficult."
The field of superconductivity is littered with remarkable claims that never reappeared in other laboratories. "When there's a real event, it reproduced relatively quickly," said Dr. Greene.
Even though the buckyball experiment has not been reproduced, Dr. Greene, director of the Center for Superconductivity at the University of Maryland, took the side of the Bell Labs researchers in his bet with Dr. Grant because of the credibility of Dr. Batlogg, a well-respected researcher in the field.
"On the other hand," Dr. Greene said, "there are some competent groups that have been working on this. I'm a little surprised it hasn't been reproduced."
Dr. Grant said the Bell Labs researchers should have gone out of their way to have someone else reproduce the experiment. "You want the greatest credibility you can gather," he said.
After protecting any potential commercial applications with patent applications, the researchers should have invited other scientists into their laboratory and provided a hands-on demonstration or gone to another lab and reproduced the experiment there, Dr. Grant said.
Although the first task of the investigating panel, headed by Dr. Malcolm Beasley, a professor of applied physics at Stanford, is to examine the issues raised so far, it has free rein to look at other areas of Dr. Schön's research, including the buckyball superconductors.
Similar Graphs Raised Suspicions on Bell Labs Research
hat had been hailed a few months ago as a breakthrough in molecule-size electronics is now in doubt, and a rising star at Bell Laboratories is under suspicion of improperly manipulating data in research papers published in prestigious scientific journals.
The accusations, by scientists not connected with the research, came to light this week, when Bell Labs appointed an independent panel to look into them. Yesterday, the scientists said that their concerns focused on graphs that were nearly identical even though they appeared in different scientific papers and represented data from different devices. In some graphs, even the tiny squiggles that should arise from purely random fluctuations matched exactly.
This is the first time in its 77-year history that Bell Labs, the distinguished research division of Lucent Technologies, has convened such a panel to look at possible misconduct by its researchers. Lucent has forwarded five papers — three published in Science, one in Nature and one in Applied Physics Letters — to the panel for investigation. The lead author of all five is Dr. J. Hendrik Schön, 31, a Bell Labs physicist in Murray Hill, N.J., who has produced an extraordinary body of work in the last two and a half years, including seven articles each in Science and Nature, two of the most prestigious journals.
In an e-mail message, Dr. Schön wrote that he would help the panel "to clarify everything as much as I can."
"Since the committee is already in place," he added, "I think it would be inappropriate to comment further at this time."
Editors at Science and Nature said they would wait for the panel's conclusions before taking action. A spokesman for Bell Labs, Saswato Das, said the panel would have full access for its inquiry. "There are serious scientific concerns," Mr. Das said, "and we would like them reviewed fully, independently and objectively."
Two articles have attracted the most attention. Last October, Dr. Schön and two other Bell Labs researchers published a paper in Nature reporting that they had made a transistor whose electronic switch was a film just one molecule thick. The finding puzzled other scientists, however. The Lucent researchers said that by applying an electric field at the edge of the film they could change the electronic properties of molecules at the center. Other scientists said the field would not penetrate that far.
In November, the Lucent researchers published a follow-up in Science saying they had produced a transistor whose switch consisted of exactly one molecule. That raised more wonderment.
"There were funny things about the data that just shouldn't have occurred," Dr. Lydia Sohn, a professor of physics at Princeton, said. "The data was just too perfect, and we knew something was wrong."
Others tried to repeat the Lucent experiments, but without success.
"We found the results to be extremely intriguing and potentially revolutionary," said Dr. Thomas N. Theis, director of physical sciences at the I.B.M. Watson Research Center in Yorktown Heights, N.Y. "We had a significant team focusing on this work and trying to reproduce the published results. So far, we have not been able to reproduce the results."
Cutting-edge research often requires new techniques that take time to learn. That other researchers cannot repeat experiments raises concern among scientists, but does not by itself suggest misconduct.
The recent molecular electronics work has been blemished, at least, by sloppiness. In a correction published in Nature, the Lucent researchers acknowledged that they had misreported the conductivity of the molecules — the numbers were too large by a factor of 10 — but said the error did not affect the conclusions.
A figure in the Science paper also turned out to be identical to one in the Nature paper, even though they referred to different transistors. Science is to publish a correction tomorrow. Dr. Schön said he had included the wrong figure by mistake.
Then someone noticed almost the same graph in yet another paper. Dr. Paul L. McEuen, a physics professor at Cornell, said he was looking through old papers on May 9 when he saw a figure in a Science article in February 2000 that looked almost identical in shape, including the noise fluctuations. That curve was for data for a transistor of a different design made of a different material, but the values appear to be greater by exactly a factor of 5.
Further examination turned up more similar graphs. A second figure in the February 2000 paper is almost identical to a figure in a Science paper published in April 2000. The shapes of the curves are again almost identical, including the random squiggles, and the values differ by a factor of almost exactly 2.
"Statistically," Dr. Sohn said, "noise is random. You know, if anything the noise should not reproduce."
Dr. McEuen said, "We found these things that seemed quite disturbing to us."
He called Dr. Schön and Lucent executives the next morning with his concerns. Lucent executives immediately started assembling their panel.
"I'm very happy with the way they responded," Dr. McEuen said. "Lucent reacted very quickly and very appropriately, I think."
Dr. Sohn cited two additional articles not among the original list of five that Lucent has given the panel. A figure in an article in Science in November 2000 appeared almost identically in Applied Physics Letters the next month and the journal Synthetic Metals last year.
"Again, it's the same curves," Dr. Sohn said. "You can put them one on top of the other, and they're identical."
Dr. Sohn and Dr. McEuen said they awaited the panel's findings to decide what caused the identical graphs.
"We're not passing judgment on anyone," Dr. Sohn said.
let's go peoples
|organized on Thursday 04-11-22 at 18:33:12|
polish Issues before Examination Gaz ziemny "Komputerowe wspomaganie w Chemii"