Ultrafast bond softening in bismuth: mapping a solid's interatomic potential with X-rays     

Fritz DM  Reis DA  Adams B  Akre RA  Arthur J  Blome C  Bucksbaum PH  Cavalieri AL  Engemann S  Fahy S  Falcone RW  Fuoss PH  Gaffney KJ  George MJ  Hajdu J  Hertlein MP  Hillyard PB  Horn-von Hoegen M  Kammler M  Kaspar J  Kienberger R  Krejcik P  Lee SH  Lindenberg AM  McFarland B  Meyer D  Montagne T  Murray ED  Nelson AJ  Nicoul M  Pahl R  Rudati J  Schlarb H  Siddons DP  Sokolowski-Tinten K  Tschentscher T  von der Linde D  Hastings JB 《Science (New York, N.Y.)》2007,315(5812):633-636

Intense femtosecond laser excitation can produce transient states of matter that would otherwise be inaccessible to laboratory investigation. At high excitation densities, the interatomic forces that bind solids and determine many of their properties can be substantially altered. Here, we present the detailed mapping of the carrier density-dependent interatomic potential of bismuth approaching a solid-solid phase transition. Our experiments combine stroboscopic techniques that use a high-brightness linear electron accelerator-based x-ray source with pulse-by-pulse timing reconstruction for femtosecond resolution, allowing quantitative characterization of the interatomic potential energy surface of the highly excited solid.  相似文献   

Does Rydberg state manipulation equal quantum computation?     

Meyer DA  Kwiat PG  Hughes RJ  Bucksbaum PH  Ahn J  Weinacht TC 《Science (New York, N.Y.)》2000,289(5484):1431a

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Uronic Acid of Chondroitin Sulfate B     

Hoffman P  Linker A  Meyer K 《Science (New York, N.Y.)》1956,124(3234):1252-1253

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Probing the Local Effects of Magnetic Impurities on Superconductivity     

A Yazdani  BA Jones  CP Lutz  MF Crommie  DM Eigler 《Science (New York, N.Y.)》1997,275(5307):1767-1770

The local effects of isolated magnetic adatoms on the electronic properties of the surface of a superconductor were studied with a low-temperature scanning tunneling microscope. Tunneling spectra obtained near magnetic adsorbates reveal the presence of excitations within the superconductor's energy gap that can be detected over a few atomic diameters around the impurity at the surface. These excitations are locally asymmetric with respect to tunneling of electrons and holes. A model calculation based on the Bogoliubov-de Gennes equations can be used to understand the details of the local tunneling spectra.  相似文献   

THE LIMIT OF UNIFORMITY IN THE GRADING OF COLLEGE STUDENTS BY DIFFERENT TEACHERS     

Meyer M 《Science (New York, N.Y.)》1914,40(1032):530-532

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Receptors: localization and specificity of binding of serotonin in the central nervous system   总被引：2，自引：0，他引：2  

S G Alivisatos  F Ungar  P K Seth  L P Levitt  A J Geroulis  T S Meyer 《Science (New York, N.Y.)》1971,171(973):809-812

Formation of a Schiff base between the ethylamine residue of serotonin and an appropriate carbonyl residue at the receptor site may be among the forces holding serotonin onto the receptor. Reduction of this imine may provide a means of permanently labeling receptors as a preliminary to their isolation.  相似文献   

Striatal nondopaminergic neurons: possible involvement in feeding and drinking behavior   总被引：1，自引：0，他引：1  

D J Pettibone  N Kaufman  M C Scally  E Meyer  I Ulus  L D Lytle 《Science (New York, N.Y.)》1978,200(4346):1175-1177

Intracaudate injections of kainic acid destroy striatal neurons containing acetylcholine and gamma-aminobutyric acid but leave dopaminergic nerve terminals in this brain region intact. Rats injected with the drug are aphagic and adipsic, and have other behavioral abnormalities strikingly similar to those seen in animals with lesions in the dopaminergic nigrostriatal bundle.  相似文献   

Primary structure of the beta subunit of the DHP-sensitive calcium channel from skeletal muscle   总被引：18，自引：0，他引：18  

P Ruth  A R?hrkasten  M Biel  E Bosse  S Regulla  H E Meyer  V Flockerzi  F Hofmann 《Science (New York, N.Y.)》1989,245(4922):1115-1118

Complementary DNAs for the beta subunit of the dihydropyridine-sensitive calcium channel of rabbit skeletal muscle were isolated on the basis of peptide sequences derived from the purified protein. The deduced primary structure is without homology to other known protein sequences and is consistent with the beta subunit being a peripheral membrane protein associated with the cytoplasmic aspect of the sarcolemma. The protein contains sites that might be expected to be preferentially phosphorylated by protein kinase C and guanosine 3',5'-monophosphate-dependent protein kinase. A messenger RNA for this protein appears to be expressed in brain.  相似文献   

Mineral inclusions in diamond: temperature and pressure of equilibration     

Meyer HO  Tsai HM 《Science (New York, N.Y.)》1976,191(4229):849-851

Two distinct suites of minerals included in natural diamond occur and probably represent different physical and chemical conditions during diamond growth. Minerals of the ultramafic suite appear to have equilibrated in the range 1000 degrees to 1300 degrees C between 45 and 65 kilobars, whereas the temperature range for minerals of the eclogitic suite is 850 degrees to 1250 degrees C. At present, models relating the partitioning of magnesium and iron between coexisting phases are not sufficiently rigorous to determine a value for the pressure of equilibration of these eclogitic suite inclusions.  相似文献   

Optically active carbon: kinetic resolution of c76 by asymmetric osmylation     

Hawkins JM  Meyer A 《Science (New York, N.Y.)》1993,260(5116):1918-1920

The chiral fullerene C(76) was kinetically resolved by asymmetric osmylation providing an example of an optically active allotrope of a pure element. C(76) recovered from the treatment of racemic C(76) with OsO(4) and a chiral alkaloid ligand, showed a specific rotation [alpha](D) of -4000 degrees (> 97 percent enantiomeric excess) and a circular dichroism spectrum corresponding to the ultraviolet spectrum. Regenerated C(76) formed by reducing the asymmetrically osmylated C(76) with SnCl(2) was enriched in the opposite enantiomer. Analysis of the local curvature of the C(76) molecule indicated that OsO(4) should selectively add to 2 of the 30 types of bonds in C(76). This regioselectivity was supported chromatographically and interpreted in terms of the kinetic resolution.  相似文献