TEA CO2激光器几种放电电极的比较

 从均匀场电极理论出发，计算并讨论了近似Rogowski电极、Chang电极(含紧凑式Chang电极)和Ernst电极的形状、理论电场分布和实际电场分布。对实验室所用的几种电极进行了脉冲放电实验，从而获得了TEA CO₂激光器的放电参数与输出特性，并对这些结果进行了比较和分析。计算表明，在基本参数相同的情况下，Ernst电极具有最紧凑的外形和最佳的均匀电场分布。实验表明，采用近似Rogowski电极的TEA CO₂激光器具有最大放电辉光范围和44 kV的最小放电击穿电压；采用Ernst电极的TEA CO₂激光器具有25 J的最高单脉冲能量和最大17.2%的斜率效率。最后提出了TEA CO₂激光器主电极的选择建议。     

微机控制仪表输出单元电路的设计与实现

设计实现了微机控制仪表的一种输出单元电路。分析了电路工作原理，总结了电路特点，在调节器设计中得到了应用。有高的性能价格比     

半线性驱动-响应系统在输出反馈控制下的混沌同步

考虑一类半线性驱动一响应系统，提出了一种实用的输出反馈控制方法并研究了相应的同步条件，通过构造误差动力系统的二次Lyapunov函数并令其导数负定，证明了当非线性项对有界自变量有界且线性部分及输出矩阵也满足一定条件时存在反馈控制使系统同步．然后将主要结果推广至多变量情形．     

光折变晶体多重全息存储衍射效率均匀性的研究

推导出了全息多重存储时间递减曝光法各幅图象写入时间的解析表达式,研究了时间递减法和循环曝光法单次曝光时间、总曝光时间以及循环次数随存储图象的幅数之间的变化关系,结果表明时间递减法不但对记录系统的要求较低,而且也可获得相当均匀的衍射效率.     

Energy dissipation and contour integral characterizing fracture behavior of incremental plasticity

Jep -integral is derived for characterizing the frac- ture behavior of elastic-plastic materials. The J ep -integral differs from Rice’s J-integral in that the free energy density rather than the stress working density is employed to define energy-momentum tensor. The J ep -integral is proved to be path-dependent regardless of incremental plasticity and deformation plasticity. The J epintegral possesses clearly clear physical meaning: (1) the value J ep tip evaluated on the infinitely small contour surrounding the crack tip represents the crack tip energy dissipation; (2) when the global steadystate crack growth condition is approached, the value of J ep farss calculated along the boundary contour equals to the sum of crack tip dissipation and bulk dissipation of plastic zone. The theoretical results are verified by simulating mode I crack problems.     

Real-time blind deconvolution of retinal images in adaptive optics scanning laser ophthalmoscopy

With the use of adaptive optics (AO), the ocular aberrations can be compensated to get high-resolution image of living human retina. However, the wavefront correction is not perfect due to the wavefront measure error and hardware restrictions. Thus, it is necessary to use a deconvolution algorithm to recover the retinal images. In this paper, a blind deconvolution technique called Incremental Wiener filter is used to restore the adaptive optics confocal scanning laser ophthalmoscope (AOSLO) images. The point-spread function (PSF) measured by wavefront sensor is only used as an initial value of our algorithm. We also realize the Incremental Wiener filter on graphics processing unit (GPU) in real-time. When the image size is 512 × 480 pixels, six iterations of our algorithm only spend about 10 ms. Retinal blood vessels as well as cells in retinal images are restored by our algorithm, and the PSFs are also revised. Retinal images with and without adaptive optics are both restored. The results show that Incremental Wiener filter reduces the noises and improve the image quality.     

Outage capacity analysis of the massive MIMO diversity channel

We consider the massive Multiple Input Multiple Output (MIMO) channel affected by independent and identically distributed Rayleigh fading, with linear processing at both transmitter and receiver sides to pursue full diversity, and analyze its outage capacity for large number of antennas. We first discuss the classical Single Input Multiple Output (SIMO) diversity channel that encompasses Maximal Ratio Combining (MRC) or Selection Combining (SC). For MRC, a numerical computation and a Gaussian Approximation (GA) are considered, whereas for SC an exact evaluation is presented. The analysis is then straightforwardly extended to the Multiple Input Single Output (MISO) diversity channel that encompasses Maximal Ratio Transmission (MRT) or transmit antenna selection. The general full diversity MIMO channel is finally considered, with optimal linear processing or simple antenna selection at both transmitter and receiver. If the number of antennas is sufficiently large on at least one side, the outage capacity of each considered diversity channel approaches that of a reference Additive White Gaussian Noise (AWGN) channel with properly defined Signal-to-Noise Ratio (SNR), which provides a performance benchmark. This conclusion is valid for large but realistic number of antennas compatible with the assumption of independent fading.     

An incremental least squares algorithm for large scale linear classification

In this work we consider the problem of training a linear classifier by assuming that the number of data is huge (in particular, data may be larger than the memory capacity). We propose to adopt a linear least-squares formulation of the problem and an incremental recursive algorithm which requires to store a square matrix (whose dimension is equal to the number of features of the data). The algorithm (very simple to implement) converges to the solution using each training data once, so that it effectively handles possible memory issues and is a viable method for linear large scale classification and for real time applications, provided that the number of features of the data is not too large (say of the order of thousands). The extensive computational experiments show that the proposed algorithm is at least competitive with the state-of-the-art algorithms for large scale linear classification.     

高重复频率LD端面抽运声光调Q腔内倍频绿光激光器

利用LD端面抽运声光调Q Nd∶YVO4激光器作为抽运源,采用线性腔实现了KTP腔内倍频高效绿光激光的输出.在调Q脉冲重复频率为40 kHz、1 064 nm输入光的功率为1 608 mW的条件下,获得了999 mW单横模（TEM00模）的绿光输出,相应的光-光转换效率为62.1%.绿光激光器输出光谱的半峰宽小于0.11 nm,其输出功率的不稳定度为±1.2%.     

Output feedback stabilization for planar switched nonlinear systems with asymmetric output constraints

In this paper, smooth output feedback controllers are presented to stabilize a class of planar switched nonlinear systems with asymmetric output constraints (AOCs). A new common barrier Lyapunov function (CBLF) is developed to prevent the switched system from violating AOCs. Combining the adding a power integrator technique (APIT) and the CBLF, state feedback controllers are designed. Then, reduced-order nonlinear observers are constructed and smooth output feedback controllers are proposed to globally stabilize planar switched nonlinear systems under arbitrary switchings. Meanwhile, the system output meets the prescribed AOCs during operation. The method proposed in this paper is a unified tool because it works not only for switched nonlinear systems with asymmetric or symmetric output constrains but also for those without output constraints. Simulations are presented to verify the proposed method.