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111.
HAN Lian-Fang CHEN Yue-Ming YUAN Hao 《理论物理通讯》2009,51(4):648-652
We propose a deterministic quantum secure direct two check photon sequences are used to check the securities of the communication protocol by using dense coding. The channels between the message sender and the receiver. The continuous variable operations instead of the usual discrete unitary operations are performed on the travel photons so that the security of the present protocol can be enhanced. Therefore some specific attacks such as denial-of-service attack, intercept-measure-resend attack and invisible photon attack can be prevented in ideal quantum channel. In addition, the scheme is still secure in noise channel. Furthurmore, this protocol has the advantage of high capacity and can be realized in the experiment. 相似文献
112.
Bing Wang Huanfeng Hao S. B. Vorozhtsov V. L. Smirnov Qinggao Yao Jinquan Zhang Mingtao Song Hongwei Zhao 《Physics of Particles and Nuclei Letters》2012,9(3):288-298
Here we present results of the computer design of the structural elements of a compact cyclotron by the example of HITFiL cyclotron selected as the driving accelerator that is under construction at the Institute of Modern Physics (Lanzhou, China). In the article a complex approach to modeling of the compact cyclotron, including calculation of electromagnetic fields of the structural elements and beam dynamics calculations, is described. The existing design data on the axial injection, magnetic, acceleration and extraction systems of the cyclotron are used as a starting point in the simulation. Some of the upgrades of the cyclotron structural elements were proposed, which led to substantial improvement of the beam quality and transmission. 相似文献
113.
114.
The electronic structure and magnetism of layered oxyselenide La(2)Mn(2)Se(2)O(3) have been studied by using first-principles calculations within the generalized gradient approximation (GGA) and GGA + U methods. The G-type antiferromagnetic (AF) state is calculated to be the most stable phase among the various magnetic configurations of interest, irrespective of the choice of the functional used, which is in good agreement with the experiments. In contrast to La(2)Fe(2)Se(2)O(3) and La(2)Co(2)Se(2)O(3), in which the AF states show metallic behavior under the GGA method, we predict the ground state of La(2)Mn(2)Se(2)O(3) is a semiconductor with an indirect band gap of ~0.52 eV via the GGA calculations. This is closely related to a closed shell configuration and large exchange splitting (~3.5 eV) in the Mn 3d states. Moreover, the magnetic properties are also discussed in terms of the calculated Heisenberg spin exchange constants, suggesting that La(2)Mn(2)Se(2)O(3) is a strong two-dimensional magnetically frustrated system. 相似文献
115.
Fractional Fourier-domain random encoding and pixel scrambling technique for double image encryption
A double image encryption method is proposed using fractional Fourier-domain random encoding and pixel scrambling technique. One of the two original images is encoded into the phase function of a synthesized input signal after being scrambled, and the other original image encoded into its amplitude. The phase function serves as phase mask in the input domain, and the synthesized input signal is then encrypted into stationary white noise by utilizing random phase encoding in fractional Fourier domain. The two original images can be retrieved without cross-talk by using the correct keys with fractional orders, the random phase mask and the pixel scrambling operator. Numerical simulations and security analysis have been done to prove the validity and the security of the proposed encryption method. 相似文献
116.
语音帧在声学特征空间中的位置信息可以辅助解码器对潜在路径进行筛选。传统的语音识别系统缺乏利用这种位置信息。针对这种不足,本文提出一种引导概率模型,用于描述语音帧属于声学特征空间不同局部的概率,并将其用于识别。使用引导概率后,解码器更强调对声学特征空间中最有希望的局部进行搜索,保留并扩展通过此局部空间的路径,同时弱化不经过此局部空间的路径。实验结果显示,融合引导概率的解码算法在不显著增加解码复杂度的情形下,使汉字相对错误率下降10.95%。结果分析表明,融合了语音帧声学位置信息的解码方法能够更有效地鉴别潜在路径,从而降低误识率。 相似文献
117.
Ammonium alum crystals are colored electrolytically using a pointed cathode and a flat anode at low temperatures and under various voltages. SO3?, SO2? and O3? hole-trapped centers are produced in colored ammonium alum crystals. Characteristic absorption bands of SO3?, SO2? and O3? hole-trapped centers are observed in absorption spectra of colored ammonium alum crystals. Production and conversion of hole-trapped centers are explained. Current–time curves for electrolytic coloration of ammonium alum crystal and their relationship with electrolytic coloration process are given. 相似文献
118.
Chuncheng Hao Zuolin Cui Yansheng Yin Zhikun Zhang 《Journal of nanoparticle research》2002,4(1-2):107-110
Nanostructured Fe3Al intermetallic compounds were produced by using hydrogen arc plasma method. The transmission electron microscopy experiments showed that the average particle size of the as-synthesized was about 40-nm. The change in hardness of Fe3Al nanostructured intermetallic compounds with annealing temperatures was observed and evaluated. 相似文献
119.
Effect of temperature on the evolution of bright and dark screening—photovoltaic spatial solitons 下载免费PDF全文
We investigate theoretically the temperature effects on the evolution of both bright and dark screening-photovoltaic optical spatial solitons in biased photovoltaic-photocefractive crystals in the case of neglecting the diffusion process.For a stable bright or dark screening-photovoltaic soliton originally formed in a crystal at a given temperature,when the crystal temperature changes,it will evolve into another stable screening-photovoltaic soliton if the change is quite small,whereas it will become unstable or break down if the temperature change is large enough.The spatial shape of a stable screening-photovoltaic soliton can be reshaped by appropriately adjusting the crystal temperature. 相似文献
120.
Atomic force microscopy investigation of growth process of organic TCNQ aggregates on SiO2 and mica substrates 下载免费PDF全文
<正>Deposition patterns of tetracyanoquinodimethane(TCNQ) molecules on different surfaces are investigated by atomic force microscopy.A homemade physical vapour deposition system allows the better control of molecule deposition. Taking advantage of this system,we investigate TCNQ thin film growth on both SiO_2 and mica surfaces.It is found that dense island patterns form at a high deposition rate,and a unique seahorse-like pattern forms at a low deposition rate.Growth patterns on different substrates suggest that the fractal pattern formation is dominated by molecule-molecule interaction.Finally,a phenomenal "two-branch" model is proposed to simulate the growth process of the seahorse pattern. 相似文献