基于Logistic映射和Arnold置乱的数字水印算法

提出了一种基于Logistic映射和Arnold变换的DCT域数字水印算法。利用Arnold变换将原始水印图像进行置乱,然后对图像进行分块DCT变换,结合Logistic映射控制水印信息的嵌入位置,把置乱后的水印图像嵌入到图像的DCT域中频系数中,进行分块DCT反变换得到水印图像。利用图像DCT系数的关系,实现了水印的盲检测。实验结果表明该算法不仅具有较好的隐蔽性,同时对常见的水印攻击具有较好的鲁棒性。     

一种基于量化的图像水印方案

本文提出一种图像自适应的扩频水印方案，利用量化-替换过程将水印嵌到图像DCT域的中高频系数上，为保证水印的鲁棒性和透明性，根据视觉模型自适应地确定水印的量化区间，在水印检测时不需要参考原图。对水印图像的攻击实验表明：算法对噪声干扰及常见的图像处理技术具有较好的鲁棒性。     

一种DCT域水印嵌入与提取算法研究

理论上,讲在DCT域的DC系数嵌入水印有更好的鲁棒性,而有意义二值图像的优点在于意义直观的。在此提出了一种DCT域的有意义二值图像水印嵌入和检测、提取算法。用二值水印图像调制伪随机序列生产水印序列,将宿主图像分块并分类,水印嵌入到DCT域的DC系数。仿真试验了嵌入、攻击和提取过程,表明该算法嵌入的水印有比较好的鲁棒性和不可见性。     

一种基于HVS和DC分量的DCT域数字水印算法

为增强数字水印的透明性和鲁棒性,提出了一种基于人类视觉系统和直流分量的DCT变换域数字水印算法。算法依据原始图像的纹理掩蔽特性确定水印信息的嵌入位置,依据照度掩蔽特性确定水印信息的嵌入强度,将二值水印图像嵌入到原始图像在DCT域的直流分量中。在仿真实验中与同等条件下的中频嵌入做比较,实验结果表明,该算法提取的水印具有良好的透明性和鲁棒性。     

基于DCT域的自适应图像数字水印盲检测算法

本文提出了一种基于DCT域的自适应图像数字水印盲检测算法,将二值图像作为有 意义水印信号间接地嵌入到原始图像中。该算法设计了一个基于HVS的分类器,根据块分类结果, 将不同强度的水印信息嵌入到图像子块的DCT域次低频系数中去,增强了算法的鲁棒性;同时提取 水印时实现了盲检测,拓宽了数字水印技术的应用范围。     

静态图像多维水印的并行嵌入和检测

数字水印已经成为多媒体数据产权保护的一种有效的解决方案，不可察觉性和鲁棒性是图像水印中基本要求，但它们却是一对互相制约的因素，在两者中间寻找一个平衡点，已经成为水印中的一个关键问题，本文提出了一种多维水印的方案，在图像的DCT域中，使用扩频技术并行地嵌 入互相独立的多维水印信号，可以在不增加水印信号幅度的情况下，提高水印的鲁棒性。     

基于信号合成与分离方法的数字图像灰度水印算法

根据图像DCT交流系数的统计特性，基于直流和交流信号的合成和分离方法，探索了一条频率域鲁棒水印的新思路。在载体DCT中频域中建立近似直流信号，把灰度水印图像置乱并调制成交流信号，水印的嵌入和检测过程转化为直流和交流信号的合成和分离过程。仿真分析表明，提出的算法具有嵌入水印信息量大、鲁棒性强和实现水印盲检测等优点。     

基于DCT的数字图像盲水印算法

提出了一种DCT域的数字图像盲水印算法。该算法首先生成水印信息,然后将宿主图像进行基于分块DCT变换,最后将水印信息嵌入到选取的各分块DCT域的中低频系数的关系中。提取水印时不需要原始图像,实现了盲检测。而且水印嵌入位置可由密码控制,增强了算法的保密性。仿真实验结果表明该算法对嵌入的水印具有较好的透明性,对常见的攻击如加噪声、JPEG压缩、滤波、颜色抖动和剪切等具有一定的鲁棒性。     

饱和检测器在数字水印方案中的应用

本文利用饱和检测器在离散余弦变换(DCT)域水印方案中进行水印检测.饱和检测器无须事先了解原始图像和水印,实现盲水印检测.在加入噪声、滤波以及压缩图片中进行水印检测,体现出了算法的鲁棒性.     

一种基于混沌映射与SVD的数字水印算法

文章提出了一种基于混沌映射与SVD的数字水印算法,利用Logistic映射对原始水印图像进行置乱加密,然后把原始载体图像分块,结合SVD和变换域水印算法的特点,把加密后的水印图像嵌入到分块图像DCT变换域的中频系数上.实验结果表明该算法有很好的鲁棒性.     

Curved crystal spectrometer for the measurement of X-ray lines from laser-produced plasmas

In order to diagnose the laser-produced plasmas, a focusing curved crystal spectrometer has been developed for measuring the X-ray lines radiated from a laser-produced plasmas. The design is based on the fact that the ray emitted from a source located at one focus of an ellipse will converge on the other focus by the reflection of the elliptical surface. The focal length and the eccentricity of the ellipse are 1350 mm and 0.9586, respectively. The spectrometer can be used to measure the X- ray lines in the wavelength range of 0.2-0.37 nm, and a LiF crystal （200） （2d = 0.4027 nm） is used as dispersive element covering Bragg angle from 30° to 67.5°. The spectrometer was tested on Shengnang- Ⅱ which can deliver laser energy of 60-80 J/pulse and the laser wavelength is 0.35 μm. Photographs of spectra including the 1 s2p ^1P1-1s^2 ^1S0 resonance line（w）, the 1s2p ^3P2-1s^2 1S0 magnetic quadrupole line（x）, the 1s2p ^3P1-1 s^2 ^1S0 intercombination lines（y）, the 1 s2p ^3S~1-1 s^2 ^1S0 forbidden line（z） in helium-like Ti Ⅹ Ⅺ and the 1 s2s2p ^2P3/2-1 s622s ^2S1/2 line（q） in lithium-like Ti Ⅹ Ⅹhave been recorded with a X-ray CCD camera. The experimental result shows that the wavelength resolution（λ/△ 2） is above 1000 and the elliptical crystal spectrometer is suitable for X-ray spectroscopy.     

Preparation and Characterization of TaN ALD Precursors

High purity organic-tantalum precursors for thin film ALD TaN were synthesized and characterized.Vapor pressure and thermal stability of these precursors were studied.From the vapor pressure analysis,it was found that TBTEMT has a higher vapor pressure than any other published liquid TaN precursor,including TBTDET,TAITMATA,and IPTDET.Thermal stability of the alkyl groups on the precursors was investigated using a 1H NMR technique.The results indicated that the tertbutylimino group is the most stable group on TBTDET and TBTEMT as compared to the dialkylamido groups.Thermal stability of TaN precursors decreased in the following order:TBTDET ＞ PDMAT ＞ TBTEMT.In conclusion,precursor vapor pressure and thermal stability were tuned by making slight variations in the ligand sphere around the metal center.     

Electronic Structure of Semiconductor Nanocrystals

This paper reviews our recent development of the use of the large-scale pseudopotential method to calculate the electronic structure of semiconductor nanocrystals, such as quantum dots and wires, which often contain tens of thousands of atoms. The calculated size-dependent exciton energies and absorption spectra of quantum dots and wires are in good agreement with experiments. We show that the electronic structure of a nanocrystal can be tuned not only by its size,but also by its shape. Finally,we show that defect properties in quantum dots can be significantly different from those in bulk semiconductors.     

Critical Stage Rule-Based Real Time Dispatch（RTD）System in Highly-Mixed-Products （HMP） FAB

An improving utilization and efficiency of critical equipments in semiconductor wafer fabrication facilities are concerned. Semiconductor manufacturing FAB is one of the most complicated and cost sensitive environments. A good dispatching tool will make big difference in equipment utilization and FAB output as a whole. The equipment in this paper is In-Line DUV Scanner. There are many factors impacting utilization and output on this equipment group. In HMP environment one of the issues is changing of reticule in this area and idle counts due to load unbalance between equipments. Here we'll introduce a rule-based RTD system which aiming at decreasing the number of recipe change and idle counts among a group of scanner equipment in a high-mixed-products FAB.     

GaAsSb/InAlAs PA DHBTs Grown by Production MBE

The epi material growth of GaAsSb based DHBTs with InAlAs emitters are investigated using a 4 × 100mm multi-wafer production Riber 49 MBE reactor fully equipped with real-time in-situ sensors including an absorption band edge spectroscope and an optical-based flux monitor. The state-of-the-art hole mobilities are obtained from 100nm thick carbon-doped GaAsSb. A Sb composition variation of less than ± 0.1 atomic percent across a 4 × 100mm platen configuration has been achieved. The large area InAlAs/GaAsSb/InP DHBT device demonstrates excellent DC characteristics,such as BVCEO＞6V and a DC current gain of 45 at 1kA/cm2 for an emitter size of 50μm × 50μm. The devices have a 40nm thick GaAsSb base with p-doping of 4. 5 × 1019cm-3 . Devices with an emitter size of 4μm × 30μm have a current gain variation less than 2% across the fully processed 100mm wafer. ft and fmax are over 50GHz,with a power efficiency of 50% ,which are comparable to standard power GaAs HBT results. These results demonstrate the potential application of GaAsSb/InP DHBT for power amplifiers and the feasibility of multi-wafer MBE for mass production of GaAsSb-based HBTs.     

Influence of polarization extinction ratio on distributed polarization coupling detection

Distributed polarization coupling in polarization-maintaining fibers can be detected by using a white light Michelson interferometer. This technique usually requires that only one polarization mode is excited. However, in practical measurement, the injection polarization direction could not be exactly aligned to one of the principal axes of the PMF, so the influence of the polarization extinction ratio should be considered. Based on the polarization coupling theory, the influence of the incident polarization extinction on the measurement result is evaluated and analyzed, and a method for distributed polarization coupling detection is developed when both two orthogonal eigenmodes are excited.     

Noise character analysis and the restraint of self-pulsation laser diodes

We calculate the Langevin noise sources of self-pulsation laser diodes, analyze the effects of active region noise and saturable-absorption region noise on the power fluctuation as well as period fluctuation, and propose a novel method to restrain the noise effects. A visible SIMULINK model is established to simulate the system, The results indicate that the effects of noise in absorption region can be ignored; that with the increase of DC injecting current, the noise effects enhance power jitter, and nevertheless, the period jitter is decreased; and that with external sinusoidal current modulating the self-pulsation laser diode, the noise-induced power jitter and period jitter can be suppressed greatly. This work is valuable for clock recovery in all-optical network.     

High-quality single-crystal CdSe nanoribbons and their optical properties

Large-scale synthesis of single-crystal CdSe nanoribbons is achieved by a modified thermal evaporation method, in which two-step-thermal-evaporation is used to control CdSe sources＇ evaporation. The synthesized CdSe nanoribbons are usually several micrometers in width, 50 nm in thickness, and tens to several hundred micrometers in length. Studies have shown that high-quality CdSe nanoribbons with regular shapes can be obtained by this method. Room-temperature photolumines-cence indicates that the lasing emission at 710 nm has been observed under optical pumping （266 nm） at power densities of 25-153 kW/cm^2. The full width half maximum （FWHM） of the lasing mode is 0.67 nm     

Propagation of hermite-cosh-gaussian beams passing through ABCD optical system with an annular aperture

By using the expansion of the aperture function into a finte sum of complex Gaussian functions, the corresponding analytical expressions of Hermite-cosh-Gaussian beams passing through annular apertured paraxially and symmetrically optical systems written in terms of ABCD matrix were derived, and they could reduce to the cases with squared aperture. In a similar way, the corresponding analytical expressions of cosh-Gaussian beams through annular apertured ABCD matrix were also given. The method could save more calculation time than that by using the diffraction integral formula directly.     

中国建立EB级存储实验室,致力云计算应用(英文)

正With the support of 863 programs,Sugon Information Industry Co.,Ltd.,set up a dawning EB-class storage laboratory to address massive data storage requirements and largescale cloud computing demonstration applications.The Dawning EB-class cloud storage system adopts advanced fault-tolerant architecture,efficient data fault-tolerant algorithms with user authentication and data encryption policies to deal with the"lost""wrong"and"stolen"problems of data for ensuring the reliability and safety of the EB-class storage system in the public network application environments.The Dawning EB-class Storage Laboratory taking advan-