双正交多子波包理论

多子波与单子波相比,可同时拥有正交性、紧支撑、对称性和高的逼近阶等特性,成为子波研究的一个新热点.为了使多子波对信号分解具有更广泛的适应性,将双正交多子波基扩展到多子波包,建立了双正交多子波包的理论框架,并把有关单子波包的定义、概念和性质推广到双正交多子波包,给出相应的证明,这将为双正交多子波的全频带快速分解和实现奠定理论基础.

正交多子波包理论

该文用类似于从正交单子波基扩展到正交单子波包的概念,建立了多子波包的理论框架,并把有关单子波包的定义、概念和性质推广到一般的多于波包,给出了相应的证明。

改进小波结合BP网络的风力发电机故障诊断

针对风力发电机早期故障时定子电流特征量难以提取的问题,提出了单子带重构改进小波变换结合BP神经网络的风力发电机故障诊断新方法。通过对风力发电机的定子电流进行单子带重构改进小波变换,消除了传统小波变换中的频率混叠现象;从小波变换后的子带信号中选取特征域、提取特征量作为BP神经网络的输入;在此基础上,结合BP神经网络的输入输出非线性映射能力,完成对故障的诊断和定位。经过仿真实验证实,该方法准确地实现了对风力发电机故障的诊断。

High-order generalized screen propagator migration based on particle swarm optimization

Various migration methods have been proposed to image high-angle geological structures and media with strong lateral velocity variations; however, the problems of low precision and high computational cost remain unresolved. To describe the seismic wave propagation in media with lateral velocity variations and to image high-angle structures, we propose the generalized screen propagator based on particle swarm optimization （PSO-GSP）, for the precise fitting of the single-square-root operator. We use the 2D SEG/EAGE salt model to test the proposed PSO-GSP migration method to image the faults beneath the salt dome and compare the results to those of the conventional high-order generalized screen propagator （GSP） migration and split-step Fourier （SSF） migration. Moreover, we use 2D marine data from the South China Sea to show that the PSO-GSP migration can better image strong reflectors than conventional imaging methods.

Accuracy analysis of the optimal separable approximation method of one-way wave migration

An approximation for the one-way wave operator takes the form of separated space and wave-number variables and makes it possible to use the FFT, which results in a great improvement in the computational efficiency. From the function approximation perspective, the OSA method shares the same separable approximation format to the one-way wave operator as other separable approximation methods but it is the only global function approximation among these methods. This leads to a difference in the phase error curve, impulse response, and migration result from other separable approximation methods. The difference is that the OSA method has higher accuracy, and the sensitivity to the velocity variation declines with increasing order.

Compact ultra-wideband monopole antenna with dual-band notched function

A kind of compact ultra wideband （UWB） monopole antenna with dual-band notched function is presented.The proposed antenna,using ＂C＂ and ＂L＂ apertures embedded in the annular ring patch and ground patch,gets two bandnotched characteristics in WiMAX3.5 GHz and WLAN 5.5 GHz.The size of antenna is 24 mm × 36 mm × 1.6 mm.The simulation results show that waveband range of the antenna is 2.7-10.6 GHz for S11 ＜-10 dB and the band-notched wavebands are 3.2-3.8 GHz and 5.1-6 GHz.So it has miniaturization,ultra-band and band-notched characteristics.Meanwhile,the radition pattern,directivety and gain are perfect,which meets the practical need.

The Reconstructing of Low Signal-noise Ratio Single Ion Channel Signal from Patch-clamp Recordings Sampled in the Colored Background Noise

The single ion channel signal is an ionic current that can be recorded by the patch clamp technique. Hidden Markov model (HMM) algorithm has been used to convert the low signal noise ratio (SNR) noisy recording into an idealized quantal one in the case of white background noise. The traditional HMM algorithm is extended and adapted to the colored background noise. A new algorithm called EHMM (Extended HMM) algorithm is proposed, and mainly validated by simulation. Results show that it’s effective.

Laser Controlling Wavepacket Trains of a Paul Trapped Ion

We have studied the quantum and classical motions of a single Paul trapped ion interacting with a timeperiodic laser field. By using the test-function method, we construct n exact solutions of quantum dynamics that describe the generalized squeezed coherent states with the expectation orbits being the corresponding classical ones. The spacetime evolutions of the exact probability densities show some wavepacket trains. It is demonstrated analytically that by adjusting the laser intensity and frequency, we can control the center motions of the wavepacket trains. We also discuss the other physical properties such as the expectation value of energy, the widths and heights of the wavepackets, and the resonance loss of stability.

A Super-Low-Noise,High-Gain MMIC LNA

A two-stage monolithic low noise amplifier is developed for satellite communication applications,using a 0.5μm enhancement PHEMT technology. The on-chip matched amplifier employs lumped elements to reduce the circuit size, and shows a 5012 noise figure less than 0.9dB, gain greater than 26dB, and return loss less than - 10dB in the S-C band range of 3.5 to 4. 3GHz. The noise figure obtained here is the best result ever reported to date of an MMIC LNA with a gain of more than 20dB for the S-C band frequency range. It is attributed to the low noise performance of the enhancement PHEMT transistor and minimized parasitic resistance of the input match network by a common series source inductor and a unique divided resistance at the drain.

Transferring and Bounding Single Photon in Waveguide Controlled by Quantum Node Based on Atomic Ensemble

We study the scattering process of photons confined in a one-dimensional optical waveguide by a laser controlled atomic ensemble. The investigation leads to an alternative setup of quantum node controlling the coherent transfer of single photon in such one dimensional continuum. To exactly solve the effective scattering equations by using the discrete coordinate approach, we simulate the linear waveguide as a coupled resonator array at the high energy limit. We generally calculate the transmission eoet^cients and its vanishing at resonance reflects the good controllability of our scheme. We also show that there exist two bound states to describe the localize photons around the cavity.

Broadband MMIC Power Amplifier for C-X-Ku-Band Applications

A three-stage MMIC power amplifier operating from 6to 18GHz is fabricated using 0.25μm A1GaAs/InGaAs/GaAs pseudomorphic high electron mobility transistor（PHEMT）.The amplifier isfully monolithic,with all matching,biasing,and DC block circuitry included on the chip.Thepower amplifier has an average power gain of 19dB over 6～18GHz.At operation frequenciesfrom 6 to 18GHz,the output power is above 33.3dBm,and the maximum output power of the MMICis 34.7dBm at 10Ghz.The input return loss is less than-10db and the out-put return is lessthan-6dB over operating frequency.This power amplifier has,to our knowledge,the best powergain flatness reported at C-X-Ku-band applications.

One-Step Generation of Scalable Multiparticle Entanglement for Hot Ions Driven by a Standing-Wave Laser

An alternative scheme is proposed for one-step generation of multiparticle cluster state with trapped ionsin thermal motion.In this scheme,the ions are simultaneously illuminated by a standing-wave laser tuned to the carrier.During the operations,the vibrational mode is virtually excited,thus the quantum operations are insensitive to theheating.It is shown that the high fidelity multiparticle entanglement could be generated in just one step even includingthe small fluctuations of parameters.In addition,the ion does not need to be exactly positioned at the node of thestanding wave,which is also important from the viewpoint of experiment.

Division of high resolution sequence stratigraphy units with wavelet transform of logs in Dagang Oilfield

Division of high resolution sequence stratigraphy units based on wavelet transform of logging data is found to be good at identifying subtle cycles of geological process in Kongnan area of Dagang Oilfield. The anal- ysis of multi-scales gyre of formation with 1-D continuous Dmey wavelet transform of log curve （GR） and I-D discrete Daubechies wavelet transform of log curve （Rt） all make the division of sequence interfaces more objec- tive and precise, which avoids the artificial influence with core analysis and the uncertainty with seismic data and core analysis.

The Gradient Estimate of a Neumann Eigenfunction on a Compact Manifold with Boundary

Let eλ（x） be a Neumann eigenfunction with respect to the positive Laplacian λ on a compact Riemannian manifold M with boundary such that A eλ = λ2eλ in the interior of M and the normal derivative of ex vanishes on the boundary of M. Let xλ be the unit band spectral projection operator associated with the Neumann Laplacian and f be a square integrable function on M. The authors show the following gradient estimate

Single-photon microwave photonics

With the rapid development of microwave photonics technology, high-speed processing and ultra-weak signal detection capability have become the main bottlenecks in many applications. Thanks to the ultraweak signal detection capability and the extremely low timing jitter properties of single-photon detectors, the combination of single-photon detection and classical microwave photonics technology may provide a solution to break the above bottlenecks. In this paper, we first report a novel concept of singlephoton microwave photonics(SP-MWP), a SP-MWP signal processing system with phase shifting and frequency filtering functionalities is demonstrated based on a superconducting nanowire single photon detector(SNSPD) and a successive time-correlated single photon counting(TCSPC) module.Experimental results show that an ultrahigh optical sensitivity down to-100 d Bm has been achieved,and the signal processing bandwidth is only limited by the timing jitter of single-photon detectors. In the meantime, the proposed system demonstrates an ultrahigh anti-interference capability, only the signal which is phase locked by the trigger signal in TCSPC can be extracted from the detected signals combining with noise and strong interference. The proposed SP-MWP concept paves a way to a novel interdisciplinary field of microwave photonics and quantum mechanism, named by quantum microwave photonics.

Ultrafast quasiparticle dynamics in spin-density-wave LaOFeAs single crystal

Ultrafast quasiparticle dynamics of single crystalline LaOFeAs were investigated by pump-probe measurement.The compound experiences structural and spin-density-wave(SDW)phase transitions at 150 K(TS1)and 130 K(TS2),respectively.The relaxation time of quasiparticles was somewhat temperature independent at high temperature but exhibited a sharp upturn at TS1and reached the maximum at approximately TS2.The remarkable slowing down of quasiparticle relaxation time is caused by the formation of energy gap.By employing the Rothwarf-Taylor model analysis,we found that there should be already energy gaps opening just below the structural transition.The magnitude of SDW gap was identified to be 72 meV.

Fabrication and characteristics of low loss and single-mode channel waveguides based on DNA-HCTAC biopolymer material

A novel biopolymer, deoxyribonucleic acid-hexadecyltrimethylammonium chloride (DNA-HCTAC), is used as the core layer material in optical waveguide, and the cleanroom technology is successfully applied to fabricate the single-mode channel waveguides with low propagation loss. The prepared DNA-HCTAC material shows high optical quality at the optical telecommunication wavelengths, such as high transparency, relatively high refractive index and low birefringence. In the fabrication approach, polymethyl methacrylate (PMMA) is used as a barrier layer to protect the DNA-HCTAC material from the corrosive of photoresist developer, and the etching conditions are optimized to form the smooth wall and sharp cross-section of the waveguide. Lastly, the optical characteristics of DNA-HCTAC channel waveguides are measured. The results show that the DNA-HCTAC waveguide operates with single-mode propagation and has a low optical loss.

A discussion on the double wave theory and its applications to description of radiation atoms

The double wave theory (DWT), sometimes called the“non_statistical quantum mechanics” by its proposer, describes the state of each single particle in an ensemble with two wave functions which have a parameter corresponding to the particle. However the basic postulates of the DWT show that this theory can hardly describe any quantum rules of the microscopic world. In the double wave descriptions, the wave feature of the behavior of microscopic particles and the discontinuity characteristic of energy almost disappear. The discussions on several problems of the radiation atoms made by the DWT's proposer on the basis of this theory are either mathematically incorrect or inconsistent with experiments and the usual theory.