共查询到18条相似文献,搜索用时 581 毫秒
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文章考察了Mo-SiO2催化剂体系在丙烯歧化反应过程中的动态ESR波谱,发现在催化歧化反应过程中有两种Mo5+顺磁中心,一种为扰动八面体配位,g||=1.89,g⊥=1.94;另一种为扰动四棱锥配位,g||=1.86,g⊥=1.95。测得同位素95,97Mo5+的各向异性超精细耦合常数A||=90.3×10-4cm-1,A⊥=44.8×10-4cm-1;观测到反应产生的积炭信号,g≈2.0O2;氧阴离子自由基信号g1=2.018,g2=2.011,g3=2.005。用LCAO-MO理论对上述Mo5+的ESR波谱进行计算,求得分子轨道系数,发现并总结出△g||/△g⊥与△g成直线关系,并建议用△g||/△g⊥=4(△E(B2→E))/(△E(B2→B1)(β1/ε)2之比值作为衡量C4v扰动程度的尺度。 相似文献
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文献[1]在计算双麦克斯韦等离子体的辐射散射结构因子的时候,区分T⊥≥T∥和T⊥≤T∥两种情况,得到两个不同形式的解析表达式。本文指出,区分这两种情况是没有必要的,可以得到具有更高精确度的统一解析表达式。
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用卷积差方法提高EPR谱的分辨率,可以从多种过渡金属离子的迭加谱中直接测量出不同离子的波谱参数aR、a⊥、gR和g⊥,该方法还可提高各向异性g因子的测量精度. 相似文献
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本文考虑到d8电子组态中所有自旋三重态和自旋单态对基态的影响,用高阶微扰法导出了d8电子组态在三角对称晶场下光谱和基态EPR普遍公式。发现在三角对称晶场下,d8电子组态离子的g⊥ > g‖或g⊥ < g‖和D > 0或D < 0是以立方对称晶场为界,晶体中顺磁离子的配体沿C3轴伸长或压缩所致。利用所得公式计算了NiCl2和NiSiF6·6H2O晶体的EPR参量,其结果与实验吻合较好。 相似文献
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Orientation-dependent electromagnetic properties of basalt fibre/nickel core--shell heterostructures 总被引:1,自引:0,他引:1
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The influence of orientation on electromagnetic properties
of basalt fibre/nickel core--shell heterostructures prepared by a
simple electroless plating method is investigated. For comparison,
the same investigation is also performed on naked basalt fibres.
For electromagnetic measurement, the directions of basalt
fibre/nickel and naked basalt fibres are parallel, random and
perpendicular to the direction of external electric field, termed
E_\vert\vert sample, random sample and E⊥ sample,
respectively. Electromagnetic anisotropy can be clearly observed in
the basalt fibre/nickel core--shell heterostructures, while
electromagnetic properties of naked basalt fibres are unrelated to
the orientation. The E⊥ basalt fibre/nickel shows the
highest dielectric loss but the lowest magnetic loss, and E|| basalt fibre/nickel exhibits the highest magnetic loss but the lowest dielectric loss. The dielectric loss of E⊥
basalt fibre/nickel is several times as large as that of E|| basalt fibre/nickel, which could be attributed to the increase of polarization relaxation time as a consequence of the
nanosize-confinement effect. The magnetic loss of E||
basalt fibre/nickel is even one order of magnitude higher than that
of E⊥ basalt fibre/nickel, which originates mainly from
the natural magnetic resonance of basalt fibre/nickel core--shell
heterostructures. 相似文献
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F.W. Büsser L. Camilleri L. Di Lella G. Gladding A. Placci B.G. Pope A.M. Smith J.K. Yoh E. Zavattini B.J. Blumenfeld L.M. Lederman R.L. Cool L. Litt S.L. Segler 《Physics letters. [Part B]》1973,46(3):471-476
Invariant cross-sections are presented for the inclusive reaction p + p → πo + anything, Measurements of large transverse momentum πo's (2.5 GeV/c<p⊥<9 GeV/c) were made near 90° at the CERN ISR at five centre-of-mass energies (√s = 23.5, 30.6, 44.8, 52.7 and 62.4 GeV. At large p⊥, the invariant cross-sections are seem to vary with s and p⊥, in good agreement with a fit of the form Ap⊥?nF(p⊥/√s), with n≈8 and F(p⊥/√s)≈exp(?26p⊥/√s). 相似文献
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H. -W. Bartels 《Zeitschrift fur Physik C Particles and Fields》1988,38(1):85-88
p ⊥ spectra of negative particles were measured for p?W and16O?W collisions at 200 GeV/u in the rapidity range 0.9<y<1.9. Within the systematic errors of 20% the spectra are identical in the range 0.05<p ⊥<2.0 GeV/c. The p?W and16O?W spectra exhibit an exponential shape forp ⊥ >250 MeV/c. This is consistent with previous p?A data, but there is a significant excess above this exponential at lowerp ⊥. Photon spectra were measured using a conversion method. Theirp ⊥ distribution agrees in shape with the sum of known hadronic γ-sources. 相似文献
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《Solid State Communications》1986,59(11):729-735
The behaviour of a quantum particle moving in a system of N coupled chains parallel to each other and packed into a bundle is investigated in the presence of weak disorder. This system may be thought of as a model of an anisotropic thin wire. The dependence of the localization length rloc on N and t⊥ is studied (t⊥ is the interchain exchange integral characterizing the strength of the interchain tunneling). For t⊥ < tc ≅ h/τ the localization length rloc increases proportionally to lt⊥/(tτ −t⊥) attaining a plateau value of the order of Nl (τ is the relaxation time and 1 the mean free path for elastic scattering). Such a behaviour may be called a transition from the Mott localization regime to the Thouless localization regime. It may be considered as a precursor of the insulator-metal transition (rloc → ∞) occuring for t⊥ → tc in the quasi-1d system (N → ∞). 相似文献
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On crystalline silicon specimens with a nonuniform carrier concentration distribution produced by an optical method, a dispersion of the effective transverse conductivity σ ⊥ eff (ω) is observed near the frequency ω≈ωc=τ ⊥ ?1 ≡ε/4πσ ⊥ eff . At ω<ωc, an anomalous transverse effective conductivity is observed: σ ⊥ eff (ω) is greater than the transverse conductivity of a homogeneous specimen σ ⊥ h (ω) (in the frequency range studied in the experiment σ ⊥ h (ω) = const). Near ω≈ωc, the conductivity σ ⊥ eff decreases, and, at ω>ωc it coincides with σ ⊥ h . 相似文献
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The observed p⊥ distributions of large mass muon pairs produced in proton-nucleus collisions are quantitatively explained in QCD by also explicitly taking into account the intrinsic wave function p⊥ spread of partons inside the hadrons. The experimental data indicate 〈p⊥〉 ~ 500–600MeV for each parton. 相似文献
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The amount and extent of structural misaligments in natural graphite crystals have been determined, and the temperature variation of the basal plane electrical conductivity (σ⊥) of naturally occurring graphite has also been studied from 300 to 90 K. The conductivity (σ⊥) has been found to obey a law σ⊥α() down to a certain temperature θ (θ varying from sample to sample), below which the variation deviates from linearity towards lower values of σ⊥. This behaviour, which was earlier thought to be a characteristic of graphite and whose origin could not be traced, has been shown to be an effect of the structural misalignments usually present in natural samples of graphite. 相似文献
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B. G. Zakharov 《JETP Letters》2018,108(8):508-512
We study the radiative correction to p⊥-broadening of a fast quark in a quark–gluon plasma beyond the soft gluon approximation. We find that the radiative processes can suppress considerably p⊥-broadening. This differs dramatically from previous calculations to logarithmic accuracy in the soft gluon approximation, predicting a considerable enhancement of p⊥-broadening. 相似文献