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1.
循环-托普利兹块相位掩模可压缩双透镜成像   总被引:2,自引:1,他引:1  
压缩成像是压缩传感理论的重要应用领域之一,可以用比Nyquist测量数目少的测量值捕获充分信息重建稀疏或可压缩图像。在研究现有的压缩成像方法的基础上,给出一种新的循环-托普利兹块相位掩模矩阵可压缩双透镜成像方法。模拟实验结果表明新的相位掩模矩阵成像方法可以在欠采样的情况下有效地获得图像信息来重建原始图像。新方法的研究为确定性测量在压缩成像领域的应用提供了更多的支撑,在拥有托普利兹和循环确定性测量优点的同时,还拥有自身的块结构特点,可以进一步减少物理实现成本。  相似文献
2.
并列式多入多出声纳宽带高分辨波束形成方法   总被引:1,自引:1,他引:0       下载免费PDF全文
杨光  王福钋  李淑秋  张祥 《应用声学》2011,30(2):131-137
并列式多入多出(Multiple-Input Multiple-Output,MIMO)声纳可以通过高分辨波束形成方法进一步提高方位分辨能力。本文通过对窄带方法的扩展,提出一种宽带高分辨波束形成的方法,数值仿真分析了该方法的性能,并通过湖试数据进行了验证。结果表明,该方法可以对并列式MIMO声纳进行宽带高分辨波束形成,高信噪比情况下可以得到较高的方位分辨能力,但方位分辨力随信噪比减小下降较快,且运算量远大于常规波束形成方法,在运算能力满足要求且信噪比较高时,用本方法可显著提高系统的方位分辨性能。  相似文献
3.
无线视频传感阵列低复杂度多视点视频编码方案   总被引:1,自引:1,他引:0  
基于网络中心节点的运动矢量外推技术,提出了一种无线视频传感阵列的低复杂度多视点视频编码方法。该方法考虑到密集型视频传感阵列各视点间通信复杂、布线繁重、且位于各相机节点内的编码器由于计算能力、功耗等限制难以完成复杂的编码过程等特点,利用运动矢量外推逼近技术将大量的运动估计运算从视频编码端移到了网络中心节点,使得新编解码框架下编码器的运动估计的计算复杂度只有传统全搜索运动估计运算的0.3%,降低了系统传感阵列编码端功耗。实验结果表明,该方法的率失真性能比H.264-I帧高出4 dB以上,接近H.264-P帧编码,优于基于Wyner-Ziv理论的分布式多视点视频编码方法。  相似文献
4.
We study the transversal spin–spin correlations in the non-equilibrium steady state of the XY chain constructed by coupling a finite cutout of the chain to the two infinite parts to its left and right acting as thermal reservoirs at different temperatures. We prove that the spatial decay of these correlations is at least exponentially fast.  相似文献
5.
It is well known that one can often construct an invariant star-product by expanding the product of two Toeplitz operators asymptotically into a series of another Toeplitz operators multiplied by increasing powers of the Planck constant h. This is the Berezin–Toeplitzquantization. We show that on bounded symmetric domains (Hermitian symmetric spaces of noncompact type), one can in fact obtain in a similar way any invariant star-productwhich is G-equivalent to the Berezin–Toeplitz star-product, by using, instead of Toeplitz operators, other suitable assignments fQ f from compactly supported C functions f to bounded linear operators Q f on the corresponding Hilbert spaces. (This procedureis referred to as prime quantization by some authors.) Along the way, we establish two technical results which are of interest in their own right, namely a controlled-growth parameter generalization of the classical theorem of Borel on the existence of a function with prescribed derivatives of all orders at a point, and the fact that any invariant bi-differential operator (Hochschild two-cochain) on a bounded symmetric domain automatically maps the Schwartz space into itself.  相似文献
6.
First we discuss the construction of self-adjoint Berezin–Toeplitz operators on weighted Bergman spaces via semibounded quadratic forms. To ensure semiboundedness, regularity conditions on the real-valued functions serving as symbols of these Berezin–Toeplitz operators are imposed. Then a probabilistic expression of the sesqui-analytic integral kernel for the associated semigroups is derived. All results are the consequence of a relation of Berezin–Toeplitz operators to Schrödinger operators defined via certain quadratic forms. The probabilistic expression is derived in conjunction with the Feynman–Kac–Itô formula.  相似文献
7.
For the zero-temperature Glauber dynamics of theq-state Potts model, the fractionr(q, t) of spins which never flip up to timet decays like a power lawr(q, t)t –(q) when the initial condition is random. By mapping the problem onto an exactly soluble one-species coagulation model (A+AA) or alternatively by transforming the problem into a free-fermion model, we obtain the exact expression of (q) for all values ofq. The exponent (q) is in general irrational, (3)=0.53795082..., (4)=0.63151575..., ..., with the exception ofq=2 andq=, for which (2)=3/8 and ()=1.  相似文献
8.
For the Gaussian and Laguerre random matrix ensembles, the probability density function (p.d.f.) for the linear statistic Σ j N =1 (x j − 〈x〉) is computed exactly and shown to satisfy a central limit theorem asN → ∞. For the circular random matrix ensemble the p.d.f.’s for the statistics ½Σ j N =1 (θ jπ) and − Σ j N =1 log 2 |sinθ j/2| are calculated exactly by using a constant term identity from the theory of the Selberg integral, and are also shown to satisfy a central limit theorem asN → ∞.  相似文献
9.
This is not primarily a paper about applications of mathematics to statistical physics, but rather a report on how a particular problem of statistical physics has resulted in an extensive mathematical theory. The problem alluded to is the computation of the spontaneous magnetizationM o (T) of the two-dimensional Ising model with nearest-neighbor interactions, whose solution for temperaturesT below the Curie pointT c was given by the famous formula of Lars Onsager in 1948. The theory grown out of this formula is the edifice of Toeplitz determinants, matrices, and operators.  相似文献
10.
For the two-dimensional Coulomb gas on a lattice, at the special value of the dimensionless coupling constant=2, the grand partition function and correlations can be written in terms of the eigenvalues and eigenvectors of a block Toeplitz matrix. By using the semiperiodic Coulomb potential and taking the continuum limit in the periodic direction so as to have a set of parallel lines as the domain, it is shown that these eigenvalues and eigenvectors can be computed exactly. This allows the pressure and the correlations near a charged wall to be rigorously evaluated. The two-particle correlations obey a sum rule which implies that the state in the vicinity of the wall is a conductor.  相似文献
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