排序方式: 共有70条查询结果,搜索用时 31 毫秒
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Ducournau G Szriftgiser P Akalin T Beck A Bacquet D Peytavit E Lampin JF 《Optics letters》2011,36(11):2044-2046
Thanks to a portable dual-frequency Brillouin fiber laser and a 1.55 μm photomixer, we report the generation of a highly coherent kilohertz level submillimeter wave emission. Low-cost telecommunications components are used to achieve very simple source architecture. The photomixer is composed of a unitravelling carrier photodiode integrated with an antenna. An emission at 316 GHz is observed and analyzed thanks to heterodyne detection with a signal-to-noise ratio >65 dB and a ~1 kHz linewidth. The phase noise of the proposed source has the same performance at 1.7 and 316 GHz. We show that this source has comparable or better phase noise compared to electrical oscillators and the tunability is much wider. 相似文献
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Toyoda H Trischuk W de Troconiz JF Truitt S Tseng J Turini N Ukegawa F Valls J Vejcik S Velev G Vidal R Vilar R Vologouev I Vucinic D Wagner RG Wagner RL Wahl J Wallace NB Walsh AM Wang C Wang CH Wang MJ Watanabe T Waters D Watts T Webb R 《Physical review letters》2000,84(10):2094-2099
We have reconstructed the radiative decays chi(b)(1P)-->Upsilon(1S)gamma and chi(b)(2P)-->Upsilon(1S)gamma in p&pmacr; collisions at sqrt[s] = 1.8 TeV, and measured the fraction of Upsilon(1S) mesons that originate from these decays. For Upsilon(1S) mesons with p(Upsilon)(T)>8.0 GeV/c, the fractions that come from chi(b)(1P) and chi(b)(2P) decays are [27.1+/-6.9(stat)+/-4. 4(syst)]% and [10.5+/-4.4(stat)+/-1.4(syst)]%, respectively. We have derived the fraction of directly produced Upsilon(1S) mesons to be [50.9+/-8.2(stat)+/-9.0(syst)]%. 相似文献
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New compounds (RFC2H4SC2H4R′F with RF=R′F ou RF≠R′F), corresponding sulfoxides and sulfones, and related compounds, were prepared, purified and characterized to investigate further the relationship between chemical structure and their usefulness as components of artificial blood.The Sulfides are chemically inert; only oxidations leading to sulfoxides and sulfones under very hard conditions (concentrated H2O2, heating) were performed.The oxygen carrier capability was leasured by two ways: —Determination of magnetic susceptibility by NMR using two different configuration spectrometers. — Gas chromatography.Results of the two methods are in good agreement and the same as the best products used as artificial blood substitutes : O2(40% vol., NMR and G.C.), N2(35% vol., G.C.), CO2(150ml/100ml G.C.). Other avantages of such products : — Synthesis quite simple, specific univocal chemical routes. -Series of homologous compounds to permit optimisation of vapor pressure and viscosity on which depends the most important parameters of emulsions - Starting materials commercially available; -Quite quantitative yields. News series of related compounds were obtained, modifying basic structure in the former step of the synthesis by chemical routes. 相似文献
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Poolman HR Boersma DJ Harvey M Higinbotham DW Passchier I Six E Alarcon R van Amersfoort PW Bauer TS Boer Rookhuizen H van Den Brand JF van Buuren LD Bulten HJ Ent R Ferro-Luzzi M Geurts DG Heimberg P de Jager CW Klimin P Koop I Kroes F van Der Laan J Luijckx G Lysenko A Militsyn B Nesterenko I 《Physical review letters》2000,84(17):3855-3858
We report on first measurements with polarized electrons stored in a medium-energy ring and with a polarized internal target. Polarized electrons were injected at 442 MeV (653 MeV), and a partial (full) Siberian snake was employed to preserve the polarization. Longitudinal polarization at the interaction point and polarization lifetime of the stored electrons were determined with laser backscattering. Spin observables were measured for electrodisintegration of polarized 3He, with simultaneous detection of scattered electrons, protons, neutrons, deuterons, and 3He nuclei, over a large phase space. 相似文献
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The crystal structures of Na2Mg3(OH)2(SO4)3 · 4H2O and K2Mg3(OH)2(SO4)3 · 2H2O, were determined from conventional laboratory X‐ray powder diffraction data. Synthesis and crystal growth were made by mixing alkali metal sulfate, magnesium sulfate hydrate, and magnesium oxide with small amounts of water followed by heating at 150 °C. The compounds crystallize in space group Cmc21 (No. 36) with lattice parameters of a = 19.7351(3), b = 7.2228(2), c = 10.0285(2) Å for the sodium and a = 17.9427(2), b = 7.5184(1), c = 9.7945(1) Å for the potassium sample. The crystal structure consists of a linked MgO6–SO4 layered network, where the space between the layers is filled with either potassium (K+) or Na+‐2H2O units. The potassium‐bearing structure is isostructural to K2Co3(OH)2(SO4)3 · 2(H2O). The sodium compound has a similar crystal structure, where the bigger potassium ion is replaced by sodium ions and twice as many water molecules. Geometry optimization of the hydrogen positions were made with an empirical energy code. 相似文献
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Zazymkina D. A. Ionin A. A. Kinyaevskiy I. O. Klimachev Yu. M. Kozlov A. Yu. Kormashova D. I. Kotkov A. A. Lampin J.-F. Mityagin Yu. A. Savinov S. A. Sagitova A. M. Sinitsyn D. V. Ionin M. V. 《Physics of Atomic Nuclei》2021,84(10):1765-1769
Physics of Atomic Nuclei - A terahertz NH3 laser optically pumped by “long” (~100 μs) pulses of an electron-beam-sustained-discharge CO2 laser is demonstrated for the first time.... 相似文献
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Ravaro M Manquest C Sirtori C Barbieri S Santarelli G Blary K Lampin JF Khanna SP Linfield EH 《Optics letters》2011,36(20):3969-3971
We report the heterodyne detection and phase locking of a 2.5?THz quantum cascade laser (QCL) using a terahertz frequency comb generated in a GaAs photomixer using a femtosecond fiber laser. With 10?mW emitted by the QCL, the phase-locked signal at the intermediate frequency yields 80?dB of signal-to-noise ratio in a bandwidth of 1?Hz. 相似文献
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