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991.
Using a diamond anvil cell device and synchrotron radiation, the in-situ high-pressure structure of SrMnO3 has been investigated. At pressure up to 28.6 GPa, no pressure-induced phase transition is observed. The lattice parameters as a function of pressure is reported, and the relationship of the axial compression coefficients is β<,a>> β<,c>. The isothermal bulk modulus K<,298>=266(4) GPa is also obtained by fitting the pressure- volume data using the Murnaghan equation of state. 相似文献
992.
We propose a scheme to achieve beam defecting and splitting using a method of embedded coordinate transformation [1]. In this
method one boundary of transformation region is not involved in the transformation, which means beam defecting and splitting
can be realized by changing the geometric construction. Although there is a discontinuous boundary, the impendence is matched
between transformation media and surrounding media according to the conventional transformation optics. Full-wave numerical
simulations further verify the theoretical analysis. 相似文献
993.
X. J. Sun J. Z. Lei M. Perc Q. S. Lu S. J. Lv 《The European Physical Journal B - Condensed Matter and Complex Systems》2011,79(1):61-66
We investigate the effects of channel noise on firing
coherence of Watts-Strogatz small-world networks consisting of
biophysically realistic HH neurons having a fraction of blocked
voltage-gated sodium and potassium ion channels embedded in their
neuronal membranes. The intensity of channel noise is determined
by the number of non-blocked ion channels, which depends on the
fraction of working ion channels and the membrane patch size with
the assumption of homogeneous ion channel density. We find that
firing coherence of the neuronal network can be either enhanced or
reduced depending on the source of channel noise. As shown in this
paper, sodium channel noise reduces firing coherence of neuronal
networks; in contrast, potassium channel noise enhances it.
Furthermore, compared with potassium channel noise, sodium channel
noise plays a dominant role in affecting firing coherence of the
neuronal network. Moreover, we declare that the observed phenomena
are independent of the rewiring probability. 相似文献
994.
Jianguo Lv Kai Huang Xuemei Chen Jianbo Zhu Lijun Wang Xueping Song Zhaoqi Sun 《Superlattices and Microstructures》2011
The chemical composition, crystalline structure, surface morphology and photoluminescence spectra of Na-doped ZnO thin films with different heat treatment process were investigated by X-ray photoelectron spectroscopy, X-ray diffraction, atomic force microscopy and a fluorescence spectrometer. The results show that preferred orientation, residual stress, average crystal size and surface morphology of the thin films are strongly determined by the preheating temperature. The effects of preheating temperature on microstructure and surface morphology have been discussed in detail. The photoluminescence spectra show that there are strong violet & UV emission, blue emission and green emission bands. The violet & UV emission is ascribed to the electron transition from the localized level below the conduction band to the valence band. The blue emission is attributed to the electron transition from the shallow donor level of oxygen vacancies to the valence band, and the electron transition from the shallow donor level of interstitial zinc to the valence band. The green emission is assigned to the electron transition from the level of ionized oxygen vacancies to the valence band. 相似文献
995.
Yue Zhao Mintao ZhouZhiyong Lv Zhao LiJian Huang Xiaoyan LiangJiahua Min Linjun Wang 《Superlattices and Microstructures》2011
Polycrystalline ZnO thin films codoped with Na and N were obtained by chemical bath deposition. The structural characteristic and the optical properties of the rapid thermal annealed ZnO:(Na,N) films were investigated by X-ray diffraction, scanning electron microscopy, energy dispersive spectrometer (EDS), Raman spectrum and room-temperature photoluminescence. After RTA treatment, the XRD spectra showed a continuous decrease of the full- width at half-maximum (FWHM) of the (0 0 2) diffraction peak of the ZnO:(Na,N) film. The Raman spectra revealed that the intensity of the mode around 582 cm−1 increased with the increase of the RTA temperature. The PL spectra showed different trends in the UV luminescence of ZnO:(Na,N) films after RTA treatments. 相似文献
996.
997.
利用强场近似(Strong field approximation,SFA)方法研究氢负离子(H-)在强激光场中双光子电离的能量谱,所得到的电离谱随角度的变化规律与实验结果符合得很好.进一步的研究表明,H-离子在强激光场中双光子电离的能量谱与有质动力能有关.激光场强度越大,光电子的有质动力能也越大,能量谱向左移动越明显... 相似文献
998.
999.
The mechanical properties of monolithic metallic glasses depend on the structures at atomic or subnanometer scales, while a clear correlation between mechanical behavior and structures has not been well established in such amorphous materials. In this work, we find a clear correlation of (27)Al NMR isotropic shifts with a microalloying induced ductile-to-brittle transition at ambient temperature in bulk metallic glasses, which indicates that the (27)Al NMR isotropic shift can be regarded as a structural signature to characterize plasticity for this metallic glass system. The study provides a compelling approach for investigating and understanding the mechanical properties of metallic glasses from the point of view of electronic structure. 相似文献
1000.
This work investigated the effect of infusion of a self-made ultrasound contrast agent with long persistence (named ZHIFUXIAN) on rat right ventricular pressure and made a preliminary evaluation on the relative safety of the novel microbubbles. Normal saline, SonoVue and ZHIFUXIAN were injected through caudal vein at the total volume of 0.5 ml for each injection. The right ventricular systolic pressure (RVSP) and end-diastolic pressure (RVEDP) were monitored and the changes of the pressure were compared with baseline readings. RVSP increased when saline, SonoVue or ZHIFUXIAN were injected, the greatest change being after SonoVue (about 2 mm Hg), but there was no statistical significance compared with baseline (P > 0.05). There was no significant difference in RVSP between saline, SonoVue and ZHIFUXIAN at any time point. Also, there was no significant difference in RVEDP between groups at each time point and between different time points in each group. The results indicate that the self-made microbubbles effect on right ventricular hemodynamics is equivalent to that of normal saline at the same volume needed for effective enhanced imaging, demonstrating that it does not produce changes in right ventricular blood pressure under the study conditions. Pathological examination also showed it had no obvious influence on lung, liver and kidney. 相似文献