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51.
Ohne Zusammenfassung
Obwohl sie dem Gebiet der „Kolloid- Zeitschrift“ ein wenig fernliegen, seien die nachstehenden Untersuchungen als Beispiel
folgerichtiger und wohl auch erfolgreicher Anwendung kolloidchemischen Denkens auf ein aktuelles praktisches Problem hier
wiedergegeben. Stellv. Schriftleitung. 相似文献
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H-shaped bridged oligothiophenes HT-1 and HT-2 were synthesized by two different approaches. Different from normal oligothiophenes, HT-1 and HT-2 showed low band gaps and amphoteric redox behaviors due to intramolecular charge transfer, which is further supported by time-dependent DFT calculations. 相似文献
54.
INFLATIONINΩ-FIELDCOSMOLOGYLeeWaTsan(李华 )Yuxin(AlfredYu)(余)(DepartmentofAppliedMathematics,HongKongPolytechnic,HongKong)(Rece... 相似文献
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We study the energy differences between mirror nuclei in both nonrelativistic (NR) and relativistic quark models based on the one-gluon exchange interaction. Both six-quark (6q) and resonating-group (RG) methods are used to treat the effects of overlapping nucleons in nuclei. The 6q method is simple and useful, but it can give only qualitative results because of a lack of precision and the neglect of non-(1s)6 configurations. It is used here to compare bag and potential models of quarks and to study the effects of kinetic energy, quark-quark interaction and nucleon size. Six-quark results show that the usual Breit-Fermi NR reduction has serious limitations in treating quark masses and nucleon sizes. In contrast, the RG method is much more complete, but it is also much harder to use. It is used here with simple NR potential models to study the effects of complicated 6q configurations, nucleon size and nucleon-nucleon short-range correlations. We find that NR potential models tend to give Nolan-Schiffer anomalies larger than experimental results, while bag models give too small results, especially if the bag radius is as small as 0.6 fm. 相似文献
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Jyh-Rou Sze An-Chi Wei Fong-Zhi Chen 《Applied Physics A: Materials Science & Processing》2010,101(1):173-178
We design three types of diffractive optical elements (DOEs) which generate pseudo-nondiffracting beams (PNDBs) in different
regions by using the conjugate gradient method. In order to analyze the influence of the tilt angles of the DOEs, the coordinate-transformation
method is used to simplify the calculation. The uniformity of the out-coupling illuminance along the optical axis is calculated.
The analyzed results show that when the tilt angle increases, the uniformity in the region [140 mm, 200 mm] has more violent
fluctuations than those in the regions [280 mm, 340 mm] and [380 mm, 520 mm]. The analyses also reveal that the uniformity
of DOEs with a longer focal length is less sensitive to the tilt angle, and some points within the PNDB region have small
variations of axial illuminance while the tilt angle increases. 相似文献
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Structural, electrical and magnetic measurements, as well as electron spin resonance (ESR) spectra, were used to characterise the single-crystalline CuCr1.6V0.4Se4 spinel and study the correlation between the negative magnetoresistance effect and magnon excitations. We established the ferromagnetic order below the Curie temperature T C ≈ 193 K, a p-type semiconducting behaviour, the ESR change from paramagnetic to ferromagnetic resonance at T C, a large ESR linewidth value and its temperature dependence in the paramagnetic region. Electrical studies revealed negative magnetoresistance, which can be enhanced with increasing magnetic field and decreasing temperature, while a detailed thermopower analysis showed magnon excitations at low temperatures. Spin–phonon coupling is explained within the framework of a complex model of paramagnetic relaxation processes as a several-stage relaxation process in which the V3+ ions, the exchange subsystem and conduction electron subsystem act as the intermediate reservoirs. 相似文献
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