Interferometer experiment with independent local oscillators   总被引：1，自引：0，他引：1  

Bare C  Clark BG  Kellermann KI  Cohen MH  Jauncey DL 《Science (New York, N.Y.)》1967,157(3785):189-191

We have operated an interferometer with independent local oscillators and without any communication link of wide bandwidth between the elements of the interferometer. This makes operation possible at very long base lines because, heretofore, construction of the communications link has been the factor limiting the separation of the elements. In our system, coherence at the two elements is maintained through the use of two highly stable, atomic oscillators. The intermediate-frequency output signals are recorded at each element on a high-speed digital tape recorder. Interference fringes are produced later by cross-correlating the two tape records in a digital computer.  相似文献   

X-ray Scattering Studies of Aligned, Stacked Surfactant Membranes     

Sirota EB  Smith GS  Safinya CR  Plano RJ  Clark NA 《Science (New York, N.Y.)》1988,242(4884):1406-1409

X-ray scattering studies were performed to understand the structure and correlations in the lamellar phases of thick, freely suspeded films of (i) the hydrated phospholipid dimyristoylphosphotidylcholine (DMPC) and (ii) the ternar system consisting of the surfactant sodium dodecyl sulfate (SDS), cosurfactant (pentanol), and water. The films were drawn in a temperature- and humidity-controlled environment, where the layers were oriented to within 0.1 degrees . In the DMPC system, this made it possible to directly observe the orientation of the P(beta') modulation and to identify phase L(beta') as three distinct phases distinguished by the direction of chain tilt with respect to the lattice. In the L(alpha) phase of the ternary system, power law behavior of the (0,0,L) structure factor arising from the algebraic decay of layer correlatios was observed in single crystals.  相似文献   

"Coulomb Staircase" at Room Temperature in a Self-Assembled Molecular Nanostructure     

RP Andres  T Bein  M Dorogi  S Feng  JI Henderson  CP Kubiak  W Mahoney  RG Osifchin  R Reifenberger 《Science (New York, N.Y.)》1996,272(5266):1323-1325

Double-ended aryl dithiols [alpha,alpha'-xylyldithiol (XYL) and 4,4'-biphenyldithiol] formed self-assembled monolayers (SAMs) on gold(111) substrates and were used to tether nanometer-sized gold clusters deposited from a cluster beam. An ultrahigh-vacuum scanning tunneling microscope was used to image these nanostructures and to measure their current-voltage characteristics as a function of the separation between the probe tip and the metal cluster. At room temperature, when the tip was positioned over a cluster bonded to the XYL SAM, the current-voltage data showed "Coulomb staircase" behavior. These data are in good agreement with semiclassical predictions for correlated single-electron tunneling and permit estimation of the electrical resistance of a single XYL molecule (approximately18 ± 12 megohms).  相似文献   

Freshwater forcing: will history repeat itself?     

Clark PU  Delworth TL  Weaver AJ 《Science (New York, N.Y.)》2008,320(5874):316-317

  相似文献   

GLOVER MORRILL ALLEN     

Clark AH 《Science (New York, N.Y.)》1942,95(2463):266-268

  相似文献   

Spontaneous formation of macroscopic chiral domains in a fluid smectic phase of achiral molecules     

DR Link  G Natale  R Shao  JE Maclennan  NA Clark  E Korblova  DM Walba 《Science (New York, N.Y.)》1997,278(5345):1924-1927

A smectic liquid-crystal phase made from achiral molecules with bent cores was found to have fluid layers that exhibit two spontaneous symmetry-breaking instabilities: polar molecular orientational ordering about the layer normal and molecular tilt. These instabilities combine to form a chiral layer structure with a handedness that depends on the sign of the tilt. The bulk states are either antiferroelectric-racemic, with the layer polar direction and handedness alternating in sign from layer to layer, or antiferroelectric-chiral, which is of uniform layer handedness. Both states exhibit an electric field-induced transition from antiferroelectric to ferroelectric.  相似文献   

Letters to the editor     

Clark C 《Science (New York, N.Y.)》1966,151(3708):279-281

  相似文献   

A POSSIBLE METHOD OF ENHANCING THE THERAPEUTIC ACTION OF ANTIBACTERIAL SERUMS     

Gay FP  Clark AR 《Science (New York, N.Y.)》1929,69(1797):604-605

  相似文献   

Mercury cratering record viewed from MESSENGER's first flyby     

Strom RG  Chapman CR  Merline WJ  Solomon SC  Head JW 《Science (New York, N.Y.)》2008,321(5885):79-81

Morphologies and size-frequency distributions of impact craters on Mercury imaged during MESSENGER's first flyby elucidate the planet's geological history. Plains interior to the Caloris basin displaying color and albedo contrasts have comparable crater densities and therefore similar ages. Smooth plains exterior to Caloris exhibit a crater density approximately 40% less than on interior plains and are thus volcanic and not Caloris impact ejecta. The size distribution of smooth-plains craters matches that of lunar craters postdating the Late Heavy Bombardment, implying that the plains formed no earlier than 3.8 billion years ago (Ga). At diameters less than or equal to 8 to 10 kilometers, secondary impact craters on Mercury are more abundant than primaries; this transition diameter is much larger than that on the Moon or Mars. A low density of craters on the peak-ring basin Raditladi implies that it may be younger than 1 Ga.  相似文献   

A COMPARISON OF THE "MAMMOTH" AND SPANISH PEANUTS AS GROWN IN CENTRAL IOWA     

Clark HW 《Science (New York, N.Y.)》1912,36(928):488-490

  相似文献