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991.
992.
M. B. Shiran K. M. Quan D. J. Watmough K. Abdellatif J. R. Mallard D. Marshall D. W. Gregory 《Ultrasonics》1990,28(6):411-414
The mapping of ultrasound fields using the dye paper method is described. The mode of action by which the dye concentration is increased has been investigated. Microbubbles on the paper surface and microstreaming of dye solution seem to be essential features of the mapping method. The streaming is thought to inhibit the formation of a dye depletion layer near the paper to an extent dependent on local sound intensity A linear relation between streaming velocity and intensity is derived. 相似文献
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Let be any function which grows more slowly than exponentially in i.e., There is a double trigonometric series whose coefficients grow like and which is everywhere convergent in the square, restricted rectangular, and one-way iterative senses. Given any preassigned rate, there is a one dimensional trigonometric series whose coefficients grow at that rate, but which has an everywhere convergent partial sum subsequence. There is a one dimensional trigonometric series whose coefficients grow like and which has the everywhere convergent partial sum subsequence For any there is a one dimensional trigonometric series whose coefficients grow like and which has the everywhere convergent partial sum subsequence All these examples exhibit, in a sense, the worst possible behavior. If is increasing and has arbitrarily large gaps, there is a one dimensional trigonometric series with unbounded coefficients which has the everywhere convergent partial sum subsequence
996.
H. Lew N. Marmet M. D. Marshall A. R. W. McKellar G. W. Nichols 《Applied physics. B, Lasers and optics》1987,44(1):5-10
We have studied the magnetic-dipole and electric-quadrupole contributions to second-harmonic generation (SHG) of centro-symmetric media. It can be shown that the phenomenological parameters , , can be arranged to form an effective
-tensor, which describes dipole-forbidden SHG as the effect of a surface layer upon excitation with a single plane electromagnetic wave. An experimental technique is proposed allowing a determination of the usually very small term due to magnetic-dipole interaction using coherent compensation of its contribution by a coverage with an appropriate dye monolayer. 相似文献
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R. Marshall 《Zeitschrift fur Physik C Particles and Fields》1989,43(4):607-613
Published data on lepton pair and quark pair final states ine + e ? annihilation have been analysed in a self consistent way to yield values for the lepton and quark weak vector and axial vector couplings. Generation universality has been tested for the leptons and under the assumption of the standard model of the weak interaction, the parameter sin2θ w has been determined separately for the lepton and quark sector. In the renormalisation scheme α,G μ and sin2θ w , the result for the lepton final states is sin2θ w = 0.212±0.014 and for the hadron final states, sin2θ w = 0.236±0.015. The combined result for this single parameter in the model is sin2θ w = 0.223±0.011±0.007, corresponding tom Z =93.0 ?1.8 +2.0 GeV. 相似文献
1000.
Stereoselective Halogenation of Integral Unsaturated C‐C Bonds in Chemically and Mechanically Robust Zr and Hf MOFs
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Ross J. Marshall Sarah L. Griffin Dr. Claire Wilson Dr. Ross S. Forgan 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(14):4870-4877
Metal–organic frameworks (MOFs) containing ZrIV‐based secondary building units (SBUs), as in the UiO‐66 series, are receiving widespread research interest due to their enhanced chemical and mechanical stabilities. We report the synthesis and extensive characterisation, as both bulk microcrystalline and single crystal forms, of extended UiO‐66 (Zr and Hf) series MOFs containing integral unsaturated alkene, alkyne and butadiyne units, which serve as reactive sites for postsynthetic modification (PSM) by halogenation. The water stability of a Zr–stilbene MOF allows the dual insertion of both ?OH and ?Br groups in a single, aqueous bromohydrination step. Quantitative bromination of alkyne‐ and butadiyne‐containing MOFs is demonstrated to be stereoselective, as a consequence of the linker geometry when bound in the MOFs, while the inherent change in hybridisation and geometry of integral linker atoms is facilitated by the high mechanical stabilities of the MOFs, allowing bromination to be characterised in a single‐crystal to single‐crystal (SCSC) manner. The facile addition of bromine across the unsaturated C?C bonds in the MOFs in solution is extended to irreversible iodine sequestration in the vapour phase. A large‐pore interpenetrated Zr MOF demonstrates an I2 storage capacity of 279 % w/w, through a combination of chemisorption and physisorption, which is comparable to the highest reported capacities of benchmark iodine storage materials for radioactive I2 sequestration. We expect this facile PSM process to not only allow trapping of toxic vapours, but also modulate the mechanical properties of the MOFs. 相似文献