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1.
(PPh4)2HP7 · 3NH3 was prepared by the reaction of K3P7 with a proton‐charged ion exchange resin in the presence of (PPh4)Br in liquid ammonia, and characterized by low temperature X‐ray structure analysis. The thermally very unstable compound contains the hydrogenheptaphosphide anion HPequation/tex2gif-stack-1.gif, the nortricyclane‐like cage of which is slightly distorted by the attachment of the hydrogen atom. 相似文献
2.
Thorsten Brand Kyle Ratinac Jeffrey V. Castro Robert G. Gilbert 《Journal of polymer science. Part A, Polymer chemistry》2004,42(22):5706-5713
A method was developed for free‐radical polymerization in the confines of a hollow latex particle. Hollow particles were prepared via the dynamic swelling method from polystyrene seed and divinylbenzene and had hollows of 500–1000 nm. So that these hollow poly(divinylbenzene) particles could function as submicrometer reactors, the particles were filled with a monomer (N‐isopropylacrylamide) via the dispersion of the dried particles in the molten monomer. The monomer that was not contained in the hollows was removed by washing and gentle abrasion. Free‐radical polymerization was then initiated by γ radiolysis in the solid state. Transmission electron microscopy showed that poly(N‐isopropylacrylamide) formed in the hollow interior of the particles, which functioned as submicrometer reactors. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 5706–5713, 2004 相似文献
3.
M. Ferro-Luzzi Z.-L. Zhou J.F.J. van den Brand H.J. Bulten J. Lang H.R. Poolman 《Hyperfine Interactions》1997,110(3-4):239-257
We present data showing hyperfine transitions in an atomic deuterium beam induced by the (476 MHz) radio-frequency field of
a 704 MeV electron beam in a storage ring. A polarized deuterium beam, produced in an atomic beam source, was crossed with
a stored electron beam and analyzed with a Breit--Rabi polarimeter. Electron-beam induced transitions were singled out by
injecting different combinations of hyperfine states. Transition probabilities as high as 70% were measured at large currents
(~ 100 mA). All possible deuterium transitions for a radio-frequency of 476 MHz were observed. In addition, a 1--6 transition
resulting from the first harmonic (952 MHz) was observed.
The effects of these transitions are of general importance for the polarized internal target technique applied in nuclear
and particle physics experiments. The data are reasonably described by numerical estimates. The observed mechanism can be
exploited to create nuclear polarized atoms when injecting electron polarized atoms with no net nuclear polarization into
a storage cell. However, when nuclear polarized atoms are injected, care should be taken to avoid this mechanism, since it
would result in depolarization of the atoms. The studies enabled us to choose the magnetic guide field during our spin-dependent
electron--deuteron scattering experiments, such that electron-beam induced depolarizing effects were avoided.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
4.
Lui Lam Flonnie Dowell Helmut Brand Guenter Ahlers 《Journal of statistical physics》1991,64(5-6):899-901
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Mössbauer effect studies of Pt3−xFe1+x fcc ordered alloys in the range 4.2 K <T<300 K, in zero and in external magnetic field, for samples with x = 0.16 to 0.28, are reported. The low-temperature spectra show several satellite lines which are related to different excess-Fe nearest-neighbor configurations. Experiments in external fields give information on the different local spin structure at different concentrations. 相似文献
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10.
G. F. Brand 《International Journal of Infrared and Millimeter Waves》2006,27(11):1445-1456
In this paper we evaluate methods for calculating dispersion relations for waves with wavelengths of the order of hundreds
of nanometres propagating in square waveguides with imperfectly conducting walls. The methods considered here are based on
those used previously for rectangular dielectric waveguides. 相似文献