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151.
从无阻尼欧拉—伯努利梁振动方程解析解出发, 推导了有限长梁的关于谱系数的时间—空间平均能量和功率流表达式. 在此基础上, 从泛函分析观点, 探讨了弯曲运动场: 衰减振动、行波模式分解关于能量、功率泛函的正交性. 结果表明: 弯曲衰减振动模式和行波模式关于功率流、机械能时间—空间平均是相互独立的, 即关于场能和场功率互不干涉, 满足叠加原理; 衰减振动场导能与行波场导能的重要区别在于功率流关于右、左衰振动模式分解不满足叠加原理, 即弯曲衰减振动场间的相互"干涉"是使其具有能量传导能力的内在原因. 通过右端集中阻尼器支撑的梁的稳态功率流仿真分析计算, 表明低频区振动导能不可忽略, 同时, 衰减振动场和行波场间存在一定的能量交换现象, 但随着频率升高, 振动场传导能量不断下降, 同时能量传导效率也不断下降. 相似文献
152.
Algora A Jordan D Taín JL Rubio B Agramunt J Perez-Cerdan AB Molina F Caballero L Nácher E Krasznahorkay A Hunyadi MD Gulyás J Vitéz A Csatlós M Csige L Aysto J Penttilä H Moore ID Eronen T Jokinen A Nieminen A Hakala J Karvonen P Kankainen A Saastamoinen A Rissanen J Kessler T Weber C Ronkainen J Rahaman S Elomaa V Rinta-Antila S Hager U Sonoda T Burkard K Hüller W Batist L Gelletly W Nichols AL Yoshida T Sonzogni AA Peräjärvi K 《Physical review letters》2010,105(20):202501
The β feeding probability of (102,104,105,106,107)Tc, 105Mo, and 101Nb nuclei, which are important contributors to the decay heat in nuclear reactors, has been measured using the total absorption technique. We have coupled for the first time a total absorption spectrometer to a Penning trap in order to obtain sources of very high isobaric purity. Our results solve a significant part of a long-standing discrepancy in the γ component of the decay heat for 239Pu in the 4-3000 s range. 相似文献
153.
154.
Lucie Perquis Hai Yen Ta Varravaddheay Ong‐Meang Alix Poinso Fabrice Collin Vrna Poinsot Franois Couderc 《Electrophoresis》2019,40(18-19):2342-2348
Tryptophane (Trp) labelled by 3‐(4‐carboxybenzoyl)‐2‐quinolinecarboxaldehyde (CBQCA) is very difficult to identify using CE and fluorescence detection (480 nm). Why in this article some mass spectrometry experiments show that Trp is really labelled by CBQCA as Leucine (Leu)? If the maximum of UV absorption (λmax) is the same between Leu‐CBQCA and Trp‐CBQCA, the molar extinction coefficient is around 2 fold higher for Trp‐CBQCA. The fluorescence of the Leu‐CBQCA derivative is 50 times more important than for Trp‐CBQCA. The addition of 7.5 mM of β‐cyclodextrin (β‐CD) was found to be a good mean to improve 2.1 fold the sensitivity of the Trp‐CBQCA fluorescence. Using a buffer containing SDS and β‐CD in CE, a LOD of 0.7 µM of L‐Trp can be reached and the ratio of the intensities between Leu, Isoleucine, Valine, Trp is 100, 21, 15, 1. Negative ESI/MS and MS/MS of the labeled amino acids show that a loss of the carboxylate function takes place. In the presence of two enantiomers of Trp‐CBQCA, we have shown that this decarboxylation is not due to the derivatization process in the solution but rather occurs in the source of the mass spectrometer. 相似文献
155.
Yuefeng Song Si Zhou Qiao Dong Yangsheng Li Xiaomin Zhang Na Ta Zhi Liu Jijun Zhao Fan Yang Guoxiong Wang Xinhe Bao 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(14):4665-4669
The oxygen evolution reaction (OER) is a sluggish electrocatalytic reaction in solid oxide electrolysis cells (SOECs) at high temperatures (600–850 °C). Perovskite oxide has been widely investigated for catalyzing the OER; however, the formation of cation‐enriched secondary phases at the oxide/oxide interface blocks the active sites and decreases OER performance. Herein, we show that the Au/yttria‐stabilized zirconia (YSZ) interface possesses much higher OER activity than the lanthanum strontium manganite/YSZ anode. Electrochemical characterization and density functional theory calculations suggest that the Au/YSZ interface provides a favorable path for OER by triggering interfacial oxygen spillover from the YSZ to the Au surface. In situ X‐ray photoelectron spectroscopy results confirm the existence of spillover oxygen on the Au surface. This study demonstrates that the Au/YSZ interface possesses excellent catalytic activity for OER at high temperatures in SOECs. 相似文献
156.
The present work is devoted to study on influences of silicon dioxide nanoparticles (SiO2) on structure and phase transition of a classical ferroelectric of triglycine sulfate (TGS) by synthesizing a composite containing SiO2 and TGS at different composition weight ratios. Particle size analysis, X-ray diffraction (XRD) and Fourier-transform infrared spectroscopy (FTIR) techniques were utilized to charaterize the synthesized composite. The experiments for investigation of phase transition were conducted from 20 to 120°C under a weak electric field (1?V.cm?1) at 1?kHz. The results revealed an expansion of ferroelectric phase of TGS by 15–55°C with increasing the SiO2 content. Besides, an additional phase transition point which is characteristic for the bulk clusters of TGS was found at low content of SiO2. The detected anomalies were discussed thoroughly based on the interaction between components in the composite. 相似文献
157.
V. Ta Phuoc C. Sellier B. Corraze E. Janod C. Marin 《The European Physical Journal B - Condensed Matter and Complex Systems》2009,69(2):181-186
Polarized infrared reflectivity was measured as a function of temperature on a quasi-one dimensional β-Sr0.17V2O5 single crystal. Along the conduction direction, the optical conductivity exhibits a weak electronic background in the far
infrared and a large mid infrared band. Sum rule analysis shows that both far infrared and midinfrared bands arise from 3d
vanadium electrons. As temperature is decreased, the mid infrared band slightly narrows and redshifts, but does not exhibit
drastic change. In contrast, the spectral weight grows at low frequencies and peaks appear in the phonon energy range. In
the transverse direction, β-Sr0.17V2O5 shows an insulator-like behaviour at all temperatures. The optical response is compared with the iso-electronic and iso-structural
compound β-Na0.33V2O5. Although spectra are very similar in both compounds at room temperature, their temperature dependence differs. However,
some general trends indicate that charge carriers are of the same nature in both compounds. The results suggest that electron-
phonon coupling is relevant to explain the optical properties of β-Sr0.17V2O5. The optical response along the conducting direction is assigned to an adiabatic small polaron absorption, in intermediate
or strong electron-phonon coupling regime. In this framework, the optical conductivity is in qualitative agreement with recent
Dynamical Mean Field Theory results over a wide temperature range. 相似文献
158.
The radioactive decay of the isotopes 254-256Lr and their daughter products was investigated by means of α , prompt α -γ and delayed conversion electron-γ coincidence
spectroscopy. The isotopes were produced using the reaction 48Ca + 209Bi . 相似文献
159.