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21.
W.D. Apel K.H. Augenstein E. Bertolucci S.V. Donskov A.V. Inyakin V.A. Kachanov R.N. Krasnokutsky M. Kruger G. Leder A.A. Lednev I. Mannelli Yu.V. Mikhailov H. Müller G.M. Pierazzini Yu.D. Prokoshkin M. Quaglia H. Schneider A. Scribano M.L. Vincelli 《Physics letters. [Part B]》1978,72(4):500-502
The invariant mass spectrum of neutral final states produced in π?p charge-exchange scattering at 40 GeV/c has been studied, searching for heavy particles decaying in 2γ. A peak is observed around 2.85 GeV/c2. The cross section of the reaction π?p→X(2.85)+n, times the branching ratio of the X→2γ decay, is measured to be . 相似文献
22.
We prove the so-called unitary isotropy theorem, a result on isotropy of a unitary involution. The analogous previously known results on isotropy of orthogonal and symplectic involutions as well as on hyperbolicity of orthogonal, symplectic, and unitary involutions are formal consequences of this theorem. A component of the proof is a detailed study of the quasi-split unitary grassmannians. 相似文献
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Maksim Zalkovskij Radu Malureanu Christian Kremers Dmitry N. Chigrin Andey Novitsky Sergei Zhukovsky Peter T. Tang Peter U. Jepsen Andrei V. Lavrinenko 《Laser \u0026amp; Photonics Reviews》2013,7(5):810-817
A planar Babinet‐inverted dimer metamaterial possessing strong optical activity is proposed and characterized. An original fabrication method to produce large area (up to several cm2) freely suspended flexible metallic membranes is implemented to fabricate the metamaterial. Its optical properties are characterized by terahertz time‐domain spectroscopy, revealing anisotropic transmission with high optical activity. A simple coupled resonator model is applied to explain the principal optical features of the dimers, with predictive power of positions and number of resonances through a parametrical model. The model is validated for correct polarization‐dependent quantitative results on the optical activity in transmission spectra. The fabrication method presented in this work as well as the slit dimer design has great potential for exploitation in terahertz optics. 相似文献
25.
S. M. Pershin V. N. Lednev M. A. Davydov V. K. Klinkov A. F. Bunkin 《Bulletin of the Lebedev Physics Institute》2013,40(6):164-167
A method for switching the regime of single-frequency generation of nanosecond pulses to a train of picosecond pulses in the Nd:YAG laser with an electro-optic Pockels Q-switch without changing cavity elements is proposed. The single-frequency regime was provided by aligning an active element which played the role of a longitudinal cavity mode selector. The lasing spectrum was measured using a Fabry-Perot interferometer with simultaneous recording of pulse oscillograms. 相似文献
26.
Maksim Navakouski Halina Zhylitskaya Piotr J. Chmielewski Tadeusz Lis Joanna Cybiska Marcin Stpie 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(15):4983-4987
Chiral heteroaromatic propellers based on radially π‐extended hexapyrrolohexaazacoronenes were obtained in a concise synthesis from suitably functionalized donor–acceptor monopyrroles. To overcome steric hindrance, a new cyclodehydrogenation method was developed, and it uses bromine electrophiles as oxidative coupling agents instead of the commonly employed high‐potential oxidants. The new reaction offers high yields of propeller‐shaped targets, even for electron‐deficient precursors, and shows electrophile‐dependent stereoselectivity, with N‐bromosuccinimide and dibromine yielding, respectively D6‐ and C2‐symmetric products. The propeller azacoronenes are chiral and can be separated into configurationally stable enantiomers. In addition to providing steric bulk, peripheral functionalization considerably affects the electronic properties of the propellers, which exhibit reduced optical and electrochemical band gaps, and a more clearly defined electroreduction behavior. 相似文献
27.
Maksim Kulichenko Nikita Fedik Prof. Dr. Konstatin V. Bozhenko Prof. Dr. Alexander I. Boldyrev 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(20):5311-5315
Growing demands of material science and, in particular, in the field of nonlinear optics (NLO) encourage us to look for stable highly polarizable molecules with excess diffuse electrons. An unusual class of compounds called electrides comply with these requirements. Many attempts have been made, yet only few electrides have been synthesized as solids and none of them as molecular species. In this paper, a new theoretically designed molecular species with electride characteristics is reported. The idea of this molecular electride comes from the formation of electride-like features in the MgO crystal with defect F-centers. The geometry of the investigated molecule can be described as a Mg4O4 cube with one oxygen atom removed. In Mg4O3, two 3s electrons are pushed out from the inner area of the molecule forming a diffuse electride multicentered bond. Our calculations show that this electride-like cluster possesses a noticeably large first hyperpolarizability β=5733 au. At the same time, a complete cube Mg4O4 and Mg4O32+ without electride electron pair have much smaller β: 0 au and 741 au, respectively. This fact indicates the decisive role of the electride electron pair in NLO properties. Additionally, vertical detachment energies of isomers (VDE), excitation energies ΔE, polarizabilities α, and IR spectra were calculated. These properties, including β, are supposed to be observable experimentally and can serve as indirect evidence of the stable molecular electride formation. 相似文献
28.
I. V. Serkov A. N. Proshin A. K. Ustinov B. V. Lednev E. V. Fomina-Ageeva A. M. Ashba V. V. Bezuglov S. O. Bachurin 《Doklady Chemistry》2018,478(1):9-11
An approach to the synthesis of adamantane derivatives with NO-generating fragment containing nitroxy group has been developed. 1-Aminoadamantane, memantine, and adamantanecarboxylic acid have been used as initial compounds. The prepared compounds have shown ability to generate nitric oxide in a system mimicking biological reactions of nitro group reduction. 相似文献
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Hashempour Mazdak Vicenzo Antonello Bahdanchyk Maksim Bestetti Massimiliano 《Journal of Solid State Electrochemistry》2018,22(12):3895-3911
Journal of Solid State Electrochemistry - The interplay and overlapping of several factors determine the capacitive behavior of carbon composite electrodes for capacitive energy storage... 相似文献