叠前地震资料复数道处理

叠前复数道处理是在叠前的CDP道集上求取三瞬参数，然后再对这些瞬时参数进行共CDP道集动校正、叠加，最终求得三瞬剖面的一种方法。该方法可以避免由于动校正拉伸和叠加等所产生的叠加地震道频谱特征发生畸变给求取三瞬参数带来不利的影响。因为共CDP道集三瞬参数的多道叠加具有统计意义，而从单道求取的瞬时频率和瞬时相位是不稳定的。实际资料处理表明，叠前复数道处理所得的瞬时频率和瞬时相位剖面的信噪比和分辨率均高于叠后复数道处理的相应剖面，且地质解释意义明显；而用这两种处理方法所得的瞬时振幅剖面品质基本相同。

一种基于分组稀疏编码的复数图像降噪算法

基于稀疏编码的复数图像降噪是目前的一个热门研究领域.该文研究一种基于分组稀疏编码的复数图像降噪算法,将复数值作为统一的整体进行分组和稀疏编码,通过限制同一分组中的图像块使用训练字典中相似的元素进行编码,从而抑制在稀疏编码过程中对噪声的编码.该文首先研究了图像块分组的算法,提出了一种图像块分组稀疏的编码算法并将其应用于复数图像的降噪问题.该文通过模拟真实的含噪干涉合成孔径雷达(InSAR)图像以及核磁共振图像(MRI)对该算法进行验证.从实验结果可以得出,相对于目前已有的算法,该文算法能够获得更低的降噪误差,特别是对于含有大片平滑区域的图像或者噪声水平较高的图像具有较大的降噪优势.

四相混沌扩频序列的优选与仿真

根据复数处理的四相异步码分多址系统的特点 ,分析了四相扩频序列的性能准则 ,提出了混沌扩频序列的优选方法。通过对大量不同初值的混沌序列进行筛选 ,得到了性能优异的混沌扩频序列组。混沌优选序列数目多 ,并且都是平衡序列。采用MonteCarlo的方法 ,在AWGN信道下 ,分别采用混沌优选序列和一类四相准最优序列作为扩频序列 ,对复数处理的异步码分多址系统进行了仿真。结果表明 ,优选的混沌序列在抗多址干扰方面与准最优序列非常接近 。

复信号检测中门限估计的野值剔除

提出了一种适用于复数据检测门限估计中野值剔除的ｋσ准则，并详细研究和比较了不同统计参量估计方法对野值剔除能力的影响，为准则的实际应用提供了分析依据。文中所导出的逐次判别剔除法可自适应野值数量较大范围的动态变化。此外，由于该准则仅要求接收信号中基底噪声服从正态分布，对异常干扰和目标信号的统计特性无任何要求，因而适用性较强。

2.488 Gbit/s clock and data recovery circuit in 0.35 μm CMOS

The design of a 2. 488 Gbit/s clock and data recovery （CDR） If for synchronous digital hierarchy （SDH） STM-16 receiver is described. Based on the injected phase-locked loop （IPLL） and D-flip flop architectures, the CDR IC was implemented in a standard 0. 35 μan complementary metal-oxide-semiconductor （CMOS） technology. With 2^31 -1 pseudorandom bit sequences （PRBS） input, the sensitivity of data recovery circuit is less than 20 mV with 10^-12 bit error rate （BER）. The recovered clock shows a root mean square （rms） jitter of 2. 8 ps and a phase noise of - 110 dBc/Hz at 100 kHz offset. The capture range of the circuit is larger than 40 MHz. With a 5 V supply, the circuit consumes 680 mW and the chip area is 1.49 mm × 1 mm.

Morphology and carbon content of WC-6%Co nanosized composite powders prepared using glucose as carbon source

Pure WC-6%Co nanosized composite powders were synthesized via a low-temperature method.The effects of carbon source on microstructure characteristic of composite powders were investigated,and the effects of heat-treatment parameter on carbon content of composite powders were also discussed.The results of SEM and XRD revealed that the carbon decomposing from glucose was more active than carbon black.Therefore,WC-Co nanosized composite powders could be synthesized at 900°C for 1 h under a hydrogen atmosphere.The individual WC grains were bonded together into a long strip under the action of cobalt.The results of carbon analysis revealed that the total carbon content decreased with the increase of the temperature in the range of 800-1000°C.Moreover,the total carbon content and the compounded carbon increased with the increase of the flow rate of H2 in the range of 1.1-1.9 m3/h.

New Estimates for the Rate of Convergence of the Method of Subspace Corrections

We discuss estimates for the rate of convergence of the method of successive subspace corrections in terms of condition number estimate for the method of parallel subspace corrections.We provide upper bounds and in a special case,a lower bound for preconditioners defined via the method of successive subspace corrections.

DECONVOLUTION IN TRANSFORM-DOMAIN FOR IMAGE DATA RESTORATION

A novel scheme for image data restoration is proposed in this letter. First, a window- function model is exploited to describe the data loss in images. It can change the restoration problem into deconvolution in transform-domain. Then, an iterative algorithm is presented to solve the deconvolution. Because the window-function is available to describe arbitrary shape, our algorithm is suitable for restoring irregular segment of data loss, including square-block. Finally, several simulation tests are done and results prove that the algorithm is valid.

Comparison of fast discrete wavelet transform algorithms

This paper presents an analysis on and experimental comparison of several typical fast algorithms for discrete wavelet transform (DWT) and their implementation in image compression, particularly the Mallat algorithm, FFT-based algorithm, Short- length based algorithm and Lifting algorithm. The principles, structures and computational complexity of these algorithms are explored in details respectively. The results of the experiments for comparison are consistent to those simulated by MATLAB. It is found that there are limitations in the implementation of DWT. Some algorithms are workable only for special wavelet transform, lacking in generality. Above all, the speed of wavelet transform, as the governing element to the speed of image processing, is in fact the retarding factor for real-time image processing.

Recovery of the gravity field from GOCE data by using the invariants of gradient tensor

The gravity field models GUCAS_EGM and GUCAS_EGM_DL are established from GOCE data (GOCE Level 2 Products from Nov. 1 to Dec. 31, 2009) based on the method of the invariants of the gravity gradient tensor, where GUCAS_EGM is derived after GOCE gravity gradient data are filtered with FIR, and GUCAS_EGM_DL is computed with an additional Durbin-Levison arithmetic apart from FIR. Since this method, different from current programs dealing with GOCE data, is introduced for the first time, some new problems are required to be discussed in advance; for example, how to filter GOCE gravity gradient data, how to compute the invariants of the gradient tensor, and how to deal with the pole gap and so on. In addition, by comparing our models with ones recommended by ESA, it can be seen that the variations of GUCAS_EGM and the models recommended by ESA to EGM08 are almost equivalent, and the variation of GUCAS_EGM_DL to EGM08 is obviously less than ones of the recommended models.

Optical colorimetric sensor arrays for chemical and biological analysis

In recent years, the sensor array has attracted much attention in the field of complex system analysis on the basis of its good selectivity and easy operation. Many optical colorimetric sensor arrays are designed to analyze multi-target analytes due to the good sensitivity of optical signal. In this review, we introduce the targeting analytes, sensing mechanisms and data processing methods of the optical colorimetric sensor array based on optical probes(including organic molecular probes, polymer materials and nanomaterials). The research progress in the detection of metal ions, anions, toxic gases, organic compounds, biomolecules and living organisms(such as DNA, amino acids, proteins, microbes and cells) and actual sample mixtures are summarized here.The review illustrates the types, application advantages and development prospects of the optical colorimetric sensor array to help broad readers to understand the research progress in the application of chemical sensor array.

Infrared emissivity and microwave absorbing property of epoxy-polyurethane/annealed carbonyl iron composites coatings

The microwave absorption property and infrared emissivity have been investigated for the single-layer coating made of the epoxy-polyurethane resin and carbonyl iron powders with variation of annealing treatment. Microwave-absorbing property was investigated by measuring the complex permittivity and complex permeability of the absorber in the frequency range from 2 to 18 GHz. Infrared emissivity value was measured using IR-2 Infrared Emissometer in the wavelength range of 8-14 μm. After annealing, the Fe （110） peak became sharp, and the crystallization improved significantly. Annealing treatment could reduce the sttrface energy of powders, improve compatibility between fillers and adhesives, and result in increase of the density of the coating. The lowest value of infrared emissivity （0.419） was obtained from the coating made of the carbonyl iron powder annealed at 700℃ for 1 h. With the variation of the annealing temperature, the magnetic and dielectric properties of the carbonyl iron particle were changed. The maximum reflection loss decreased and the matching frequency shifted to lower frequency with increasing the annealing temperature of carbonyl iron particles, which coincided with the variation of the complex permeability and permittivity according to the annealing temperature. Magnetic loss factor and dielectric loss factor of carbonyl iron particles were improved with increasing the annealing temperature in the 2-18 GHz range.

A proximal alternating linearization method for minimizing the sum of two convex functions

In this paper, we develop a novel alternating linearization method for solving convex minimization whose objective function is the sum of two separable functions. The motivation of the paper is to extend the recent work Goldfarb et al.(2013) to cope with more generic convex minimization. For the proposed method,both the separable objective functions and the auxiliary penalty terms are linearized. Provided that the separable objective functions belong to C1,1(Rn), we prove the O(1/?) arithmetical complexity of the new method. Some preliminary numerical simulations involving image processing and compressive sensing are conducted.