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101.
A new method to protect the copyright of digital museum based on digital holography is proposed. The Fresnel hologram of watermark image is embedded in the object to be protected through discrete wavelet transform (DWT). After the watermark detection, the copyright information appears in the reconstructed hologram. With the higher redundancy feature in the hologram, the proposed technique can actually survive several kinds of image processing. Experimental results prove that the presented method has good robustness in image protection. 相似文献
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Improvement of Security of Three-Party Quantum Secure Direct Communication Based on GHZ States 总被引:2,自引:0,他引:2 下载免费PDF全文
A protocol for three-party quantum secure direct communication based on Greenberger-Horne-Zeilinger (GHZ) states was recently proposed by 3in et al. [Phys. Lett. A 354 (2006) 67] By analysing the protocol we find some security loopholes, e.g. one bit of secret messages of a party (Alice in the original paper) can always be leaked straight to the public without any eavesdropping. These problems suggested previously are discussed and possible solutions are presented to improve the security of the original protocol. 相似文献
105.
Experimental Study on Electrostatic with Two Guiding of Supersonic D20 Molecular Beam Charged Wires 下载免费PDF全文
We demonstrate the guiding of a supersonic heavy-water (D2O) molecular beam using a hollow electrostatic field generated by the combination of two parallel charged-wires and two grounded metal-plates, and report some new and preliminary experimental results. In the experiment, we detect the guiding signals by using the method of time-of-flight mass spectrum and study the dependence of the relative transmission of the beam guide on the guiding voltage. Our study shows that the relative transmission of the beam guide is increased linearly with increasing guiding voltage Vguid, and the number of the guided D20 molecules is at least increased by 89.4% when the guiding voltage is +20.0k V. Finally, some potential applications of our guiding scheme in the molecule optics are briefly discussed. 相似文献
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Hydrogen Passivation Effect on Enhanced Luminescence from Nanocrystalline Si/SiO2 Multilayers 下载免费PDF全文
Nanocrystalline Si/SiO2 multilayers are prepared by thermally annealing amorphous Si/SiO2 stacked structures. The photoluminescence intensity is obviously enhanced after hydrogen passivation at various temperatures. It is suggested that the hydrogen trapping and detrapping processes at different temperatures strongly influence the passivation effect. Direct experimental evidence is given by electron spin resonance spectra that hydrogen effectively reduces the nonradiative defect states existing in the Si nanocrystas/SiO2 system which enhances the radiative recombination probability. The luminescence characteristic shows its stability after hydrogen passivation even after aging eight months. 相似文献
107.
对用稳定图识别真假模态的一点改进 总被引:1,自引:0,他引:1
利用单位样值响应矩阵和自由响应的特征值分解形式中的特征值前的系数矩阵的范数作稳定判据,结合稳定图识别真假模态,计算表明,本方法具有较好的分解能力。 相似文献
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在 Bi_(1.6)Pb_(0.4)Ca_2Sr_2Cu_3O_y 样品中存在着110K 和85K 两个超导相,样品的零电阻温度为105K.磁化率、比热以及不同温度下的 M-H 曲线测量结果均表明85K 相为表面超导相,在样品中占有较小的体积分数.文中还报道了样品的H_(c1)(0). 相似文献