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排序方式: 共有131条查询结果,搜索用时 31 毫秒
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Paolo Finocchiaro Salvatore Failla Giuseppe A. Consiglio Mark Wehner Thomas Grawe Thomas Schrader 《Phosphorus, sulfur, and silicon and the related elements》2013,188(6-7):1633-1636
We present here a new class of cleft-like receptor molecules containing two or four phosphonates anions, tailored for multipoint binding of their substrates. Depending on the accessibility of the cleft, these hosts are water soluble and selective for short or long f , y -diammonium compounds. Due to their inherent chirality, we found that only those host-guest combinations which allow a three-point-interaction were effective. 相似文献
64.
针对液氧/煤油火箭发动机模型燃烧室实现了三维非稳态两相燃烧过程的数值模拟,得到的燃烧室截面平均压力和平均速度与实验吻合。在初边值条件不施加任何扰动的情况下,得到了燃烧室压力自激振荡过程,并研究了液氧和煤油喷嘴雾化角对燃烧室压力振荡的影响。计算结果表明:当雾化角为40°或120°时,由于燃料与氧化剂喷雾锥重叠区域较小或较大,导致了推进剂混合很差或很好,不易在燃烧室头部出现局部爆炸性的可燃混气团,致使燃烧室压力振荡强度较弱;而当雾化角为中间值65°时,易于出现爆炸性的可燃气团并导致剧烈的压力振荡,使燃烧室中出现燃烧不稳定性。因此,雾化角的合理设计是抑制燃烧不稳定性的一种途径。 相似文献
65.
S. V. Borisov M. Boezio S. A. Voronov A. M. Galper G. Jerse A. V. Karelin E. Mocchiutti P. Picozza O. Adriani G. A. Bazilevskaya R. Bellotti V. Bonvicini L. Bonechi S. Bottai A. Bruno A. Vacchi E. Vannuccini G. Vasil’ev J. Wu L. Grishantseva M. P. De Pascale C. De Santis N. De Simone V. Di Felice W. Gillard G. Zampa N. Zampa V. G. Zverev M. Casolino D. Campana R. Carbone G. Castellini P. Carlson F. Cafagna A. N. Kvashnin S. V. Koldashov L. Consiglio S. Yu. Krutkov A. Leonov V. Malvezzi L. Marcelli W. Menn V. V. Mikhailov A. Monaco N. Mori N. Nikonov G. Osteria P. Papini M. Pearce S. B. Ricciarini M. Ricci L. Rossetto M. Simon R. Sparvoli P. Spillantini Yu. I. Stozhkov P. Hofverberg Yu. T. Yurkin 《Bulletin of the Lebedev Physics Institute》2010,37(6):184-190
The PAMELA magnetic spectrometer onboard the Resurs DK1 satellite no. 1 was put into (Earth) orbit on June 15, 2006; measurements continue at the present time. The scientific objective of the spectrometer is the study of antiproton, proton, positron, electron and light nucleus fluxes in cosmic rays. In this paper, we present the technique for measuring electron and positron spectra in the energy range from 20 to 800 GeV. 相似文献
66.
在 pH 6.0的 HAc-NaAc缓冲溶液中,用活性炭吸附沙枣中的色素,Cu(Ⅱ)催化氧化维生素C,在λmax=268 nm处可直接测定沙枣中维生素C含量.与传统碘量法相比,测定结果基本一致.为内蒙古地区沙枣天然植物资源的药用开发、食品加工等提供了参考数据. 相似文献
67.
G. Alonzo M. Consiglio F. Maggio N. Bertazzi 《Phosphorus, sulfur, and silicon and the related elements》2013,188(1-4):287-289
Abstract A linear correlation between the chemical isomer shift and the quadrupole coupling constant for a number of antimony tris-thiolates has been evidenced. This behaviour can be rationalized on considering a modulation of the s/p character of the lone pair of electrons from the influence of secondary bonds. 相似文献
68.
We develop a scenario optimization model for asset and liability management of individual investors. The individual has a
given level of initial wealth and a target goal to be reached within some time horizon. The individual must determine an asset
allocation strategy so that the portfolio growth rate will be sufficient to reach the target. A scenario optimization model
is formulated which maximizes the upside potential of the portfolio, with limits on the downside risk. Both upside and downside
are measured vis-à-vis the goal. The stochastic behavior of asset returns is captured through bootstrap simulation, and the simulation is embedded
in the model to determine the optimal portfolio. Post-optimality analysis using out-of-sample scenarios measures the probability
of success of a given portfolio. It also allows us to estimate the required increase in the initial endowment so that the
probability of success is improved. 相似文献
69.
A compact laser diode-pumped solid-state Nd:LuVO4 acousto-optic Q-switched laser is demonstrated at 916 nm of a quasi-three level for the first time. A pulse width of 130ns is observed when the pulse-repetition frequency is 10 kHz. The laser experiment shows that the Nd:Lu VO4 crystal can be used for efficient diode-pumped Q-switched lasers. 相似文献
70.
Adriani O Barbarino GC Bazilevskaya GA Bellotti R Boezio M Bogomolov EA Bongi M Bonvicini V Borisov S Bottai S Bruno A Cafagna F Campana D Carbone R Carlson P Casolino M Castellini G Consiglio L De Pascale MP De Santis C De Simone N Di Felice V Galper AM Gillard W Grishantseva L Jerse G Karelin AV Koldashov SV Krutkov SY Kvashnin AN Leonov A Malakhov V Malvezzi V Marcelli L Mayorov AG Menn W Mikhailov VV Mocchiutti E Monaco A Mori N Nikonov N Osteria G Palma F Papini P Pearce M Picozza P 《Physical review letters》2011,106(20):201101
Precision measurements of the electron component in the cosmic radiation provide important information about the origin and propagation of cosmic rays in the Galaxy. Here we present new results regarding negatively charged electrons between 1 and 625 GeV performed by the satellite-borne experiment PAMELA. This is the first time that cosmic-ray e? have been identified above 50 GeV. The electron spectrum can be described with a single power-law energy dependence with spectral index -3.18 ± 0.05 above the energy region influenced by the solar wind (> 30 GeV). No significant spectral features are observed and the data can be interpreted in terms of conventional diffusive propagation models. However, the data are also consistent with models including new cosmic-ray sources that could explain the rise in the positron fraction. 相似文献