S型非线性调频信号及其多普勒频率范围

给出了S型非线性调频信号的传递函数，由传递函数算出了群延迟、频谱函数和模糊函数表达式，并根据模糊函数获得了S型调频信号的各项基本性能。     

高阶非线性频率调制雷达信号的脉冲压缩方法研究

根据经典的模糊函数和脉冲压缩理论,提出了基于匹配傅里叶变换的高阶非线性频率调制信号的模糊函数和脉冲压缩的方法,其脉冲压缩效果与线性调频信号接近;并进行了仿真,证明高阶非线性频率调制信号可以被压缩。     

基于高速ECL数字电路的宽带多模信号的产生和设计

该文给出了一种基于高速ECL数字电路的宽带多模信号产生系统,并简要介绍了线性调频(LFM),非线性调频(NLFM)信号产生系统的设计方法。该文实现系统的时钟频率为280MHz,可输出带宽70MHz以下的多种时宽的LFM,NLFM信号。实际测试结果表明,该宽带信号产生系统输出的谐波与杂散均小于-55dB,完全可以满足工程应用的要求。     

基于调频函数和遗传算法的非线性调频信号产生方法

在雷达领域中,利用非线性调频脉冲压缩中提高脉压系统的性能,本文根据我们已建立的调叔函数模型,提出了一种利用多参量遗传算法来产生满足脉压系统需求的非线性调频信号的方法,给出一个用该方法设计非线性调频信号的实例,实验结果表明,这一方法能够快速灵活地设计出所需信号。     

基于FPGA的非线性调频信号脉冲压缩的实现

非线性调频信号在信号设计时即考虑到脉冲压缩信号距离旁瓣的抑制,无需在硬件实现中添加加权网络抑制距离旁瓣。文中介绍了非线性调频信号的设计方法,通过Matlab仿真验证了不同设计方法的非线性调频信号的脉冲压缩性能。并在FPGA仿真环境下实现了带宽30 MHz,采样率为100 MHz,输入信号量化位数为16 bit,时长为10.24 μs的线性和非线性调频信号的脉冲压缩。     

基于多项式拟合的非线性调频波形设计

在非线性调频(NLFM)脉压波形设计的一般原理基础上,提出了一种基于多项式拟合的波形设计方法。用该设计方法设计出的NLFM波形具有低的距离旁瓣和好的多普勒性能,且不需要给出调频和调相显函数的表达式,设计更为灵活、简单,通过大量仿真实验分析了该方法所产生的波形性能与采样频率、多普勒的关系,并根据卷积定理仿真了信号的模糊函数。仿真结果验证了该方法的有效性和可行性。     

Q调红宝石激光器非线性频率线性调频脉冲的测量

用两种干涉实验——旋转物体的全息照相和时间相干测量研究了Q开关红宝石激光器的频率线性调频脉冲。在两束光之间时间差大时,频率线性调频脉冲的非线性显著地影响两种干涉实验,这可使我们确定非线性频率线性调频,即线性频率速率和时间。双曲线正切函数比一般采用的线性函数能较好地近似描绘频率线性调频。在此实验中,线性调频脉冲时间为脉冲半强度宽度的1～1.5倍。     

基于乘积性模糊函数的核函数设计方法

利用乘积性模糊函数,提出一种双线性时频分布的核函数设计新方法,能够在模糊域有效地抑制噪声和多分量间的交叉项.在多分量强弱信号环境中,提出基于逐次减小误差的递归算法重构强信号,减小传统分析方法的残余信号影响和参数误差传播效应.利用分段近似的原则,可将非线性调频信号分解为多分量线性调频信号,从而将核函数设计方法推广到非线性调频信号环境.最后,仿真结果证实了该方法对多分量调频信号的有效性.     

基于GASA算法和调频函数的NLFM波形设计

与线性调频信号相比,非线性调频信号无需加权就可以获得很低的距离旁瓣,而且没有信噪比损失,在脉压雷达中得到广泛的应用。一般地,设计非线性调频信号都采用基于相位逗留原理的窗函数法,但是设计的波形有很高的距离旁瓣。在分析了窗函数法设计非线性调频信号的基础上,根据一种新的调频函数数学模型,提出了一种用GASA算法来产生非线性调频信号的新方法,并给出了仿真实例,仿真验证了该算法的有效性。通过该方法获得了脉压后低副瓣的非线性调频信号,可以提高脉冲压缩性能。     

非线性调频信号脉压分析与仿真

介绍了几种利用非线性调频信号进行脉冲压缩的算法。建立了三次方调频、正切调频、正弦调频的非线性调频信号模型,并在此基础上进行了这三种函数的非线性调频信号脉冲压缩仿真。     

Cost-effective test solutions for smart card and other integrated flash applications

From its emergence in the late 1980s as a lower cost alternative to early EEPROM technologies, flash memory has evolved to higher densities and speedsand rapidly growing acceptance in mobile applications.In the process, flash memory devices have placed increased test requirements on manufacturers. Today, as flash device test grows in importance in China, manufacturers face growing pressure for reduced cost-oftest, increased throughput and greater return on investment for test equipment. At the same time, the move to integrated flash packages for contactless smart card applications adds a significant further challenge to manufacturers seeking rapid, low-cost test.     

An improved parallel thinning algorithm with two subiterations

The parallel thinning algorithm with two subiterations is improved in this paper. By analyzing the notions of connected components and passes, a conclusion is drawn that the number of passes and the number of eight-connected components are equal. Then the expression of the number of eight-connected components is obtained which replaces the old one in the algorithm. And a reserving condition is proposed by experiments, which alleviates the excess deletion where a diagonal line and a beeline intersect. The experimental results demonstrate that the thinned curve is almost located in the middle of the original curve connectivelv with single pixel width and the processing speed is high.     

Theoretical analysis of the relationship between the Brillouin gain coefficient and the strain in the optical-fiber sensors

The relation between the power of the Brillouin signal and the strain is one of the bases of the distributed fiber sensors of temperature and strain. The coefficient of the Bfillouin gain can be changed by the temperature and the strain that will affect the power of the Brillouin scattering. The relation between the change of the Brillouin gain coefficient and the strain is thought to be linear by many researchers. However, it is not always linear based on the theoretical analysis and numerical simulation. Therefore, errors will be caused if the relation between the change of the Brillouin gain coefficient and the strain is regarded as to be linear approximately for measuring the temperature and the strain. For this reason, the influence of the parameters on the Brillouin gain coefficient is proposed through theoretical analysis and numerical simulation.     

Novel fiber-optical interferometer with miniaturized probe for in-hole measurements

Today, micro-system technology and the development of new MEMS （Micro-Electro-Mechanical Systems） are emerging rapidly. In order for this development to become a success in the long run, measurement systems have to ensure product quality. Most often, MEMS have to be tested by means of functionality or destructive tests. One reason for this is that there are no suitable systems or sensing probes available which can be used for the measurement of quasi inaccessible features like small holes or cavities. We present a measurement system that could be used for these kinds of measurements. The system combines a fiber optical, miniaturized sensing probe with low-coherence interferometry, so that absolute distance measurements with nanometer accuracy are possible.     

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.     

Teleportation of an arbitrary unknown N-qubit entangled state under the controlling of M controllers

A new quantum protocol to teleport an arbitrary unknown N-qubit entangled state from a sender to a fixed receiver under M controllers(M < N) is proposed. The quantum resources required are M non-maximally entangled Greenberger-Home-Zeilinger (GHZ) state and N-M non-maximally entangled Einstein-Podolsky-Rosen (EPR) pairs. The sender performs N generalized Bell-state measurements on the 2N particles. Controllers take M single-particle measurement along x-axis, and the receiver needs to introduce one auxiliary two-level particle to extract quantum information probabilistically with the fidelity unit if controllers cooperate with it.     

Diode-end-pumped Nd:YVO4/LBO lasers with 4.2W continuous-wave output at 457 nm

A continuous-wave (CW) 457 nm blue laser operating at the power of 4.2 W is demonstrated by using a fiber coupled laser diode module pumped Nd: YVO4 and using LBO as the intra-cavity SHG crystal With the optimization of laser cavity and crystal parameters, the laser operates at a very high efficiency. When the pumping power is about 31 W, the output at 457nm reaches 4.2 W, and the optical to optical conversion efficiency is about 13.5% accordingly. The stability of the out putpower is better than 1.2% for 8 h continuously working.     

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.