The Diagonal Functors

We obtain new categorical proofs that generalize the diagonal principles introduced in Castillo and Moreno (Israel J. Math. 140:253–270, 2004) to study the automorphic and partially automorphic character of Banach spaces. We then introduce and study the automorphy index for a Banach space, showing that while . This research has been supported in part by project MTM2004-02635.     

Explosive first-order transition to synchrony in networked chaotic oscillators

Critical phenomena in complex networks, and the emergence of dynamical abrupt transitions in the macroscopic state of the system are currently a subject of the outmost interest. We report evidence of an explosive phase synchronization in networks of chaotic units. Namely, by means of both extensive simulations of networks made up of chaotic units, and validation with an experiment of electronic circuits in a star configuration, we demonstrate the existence of a first-order transition towards synchronization of the phases of the networked units. Our findings constitute the first prove of this kind of synchronization in practice, thus opening the path to its use in real-world applications.     

Efficient coupling of light into and out of a photonic crystal waveguide via surface modes

In this paper, we show how the coupling of light into a photonic crystal waveguide can be greatly enhanced by creating a periodic modulation in the dielectric structure surrounding the entrance of the waveguide. In this way, surface modes supported by the system can funnel the light that impinges onto the surface into the interior of the waveguide. Moreover, we also demonstrate that the shape and direction of the beam that emerges from the structure can be tailored by constructing a periodic corrugation near the exit side of the waveguide.     

光学测量中椭圆圆心定位算法研究

提出了一种椭圆圆心定位算法。先对图像中的椭圆目标进行粗定位,获取椭圆的粗定位信息,再用Canny算子对图像中的感兴趣区域进行边缘检测。根据椭圆的粗定位信息以及图像的边缘灰度分布特征,用高斯曲线拟合的方法求得精确的亚像素边缘点的坐标。针对亚像素边缘点中出现的“孤立点”以及噪声点,分别用曲率滤波和均值滤波的方法加以滤波,将滤波后的亚像素边缘点用最小二乘法加以拟合,求得精确的椭圆圆心数据。实验证明了该算法的定位精度和抑制噪声能力,通过测试算法运行时间,证明该算法具有很好的实时性。     

超声调制介质中漫散射光自相关性质研究

研究了超声调制随机介质中漫散射光自相关性质,推导出均匀无限介质中有超声场调制时漫散射光时间自相关函数的表达式,讨论了调制参数、调制幅度及其衰减与超声参数、光散射参数等的关系.用Monte Carlo方法研究了随机介质中隐含异物成像的可行性.结果表明,正常生物组织和病变生物组织的超声调制自相关函数有明显的差别,该方法为光学医学诊断提供了一种新参考 关键词： 自相关 漫散射光 超声调制 光学成像     

高斯光束共焦扫描激光显微镜的光学传递函数

考虑光源和探测器有一定大小，并引入光源的高斯分布函数，求出此接近实际的共焦扫描成像系统的光学传递函数(OTF)；运用计算机进行数值模拟并讨论光源针孔和探测针孔的大小对横向、纵向分辨率的影响.所得结果在不影响共焦扫描成像系统三维(3D)成像能力的基础上，可以有效地提高系统的信噪比. 关键词：     

用纵横波声时比法测螺栓轴力精度研究

用纵横波测量螺栓轴力的技术已取得较大发展,本文介绍了纵横波比值法原理,通过理论推导,获得比值法计算的简易公式。建立试验平台,用现场用螺栓进行标定和测量,得出比值法在工程实践状态下的测量误差为10%以内,基本能满足工程应用的要求。此外,针对试验结果,本文还初步探讨了误差出现的原因以及提高精度的方法。本文介绍的比值法,无需精确测量标定螺栓长度和纵横波声速,现场应用更加简洁,具有较大的工程应用价值。     

Interlaced size exclusion liquid chromatography of monoclonal antibodies

Size exclusion chromatography is a widely performed analysis of monoclonal antibodies, primarily used to monitor the levels of higher weight molecular species such as aggregates. Owing to the subtleties of these separation mechanisms and frequently observed partial resolutions of components in these separations, many common methods for increasing the method throughput are not practical as they trade off resolution for speed. Short columns, high flow rates and smaller particles are examples of these approaches. In this paper a practical method is demonstrated for injecting samples onto the column in rapid succession and gating the detection window to monitor the elution of each sample individually. At any given instant approximately two samples are eluting through the column. By co-ordinating the injection and detection time windows the samples can be kept discrete and significant throughput enhancements achieved, up to nearly 2-fold improvements are demonstrated. A rudimentary theory is development to show that the throughput improvements can be predicted to approximation by simple column characteristics. Experimental results for a series of monoclonal antibodies demonstrate the equivalency of the method to a conventional injection approach, the throughput increase, and the robustness of the method.     

Modeling of gain and phase dynamics in quantum dot amplifiers

By means of an electron hole rate equation model we explain the phase dynamics of a quantum dot semiconductor optical amplifier and the appearance of different decay times observed in pump and probe experiments. The ultrafast hole relaxation leads to a first ultrafast recovery of the gain, followed by electron relaxation and, in the nanosecond timescale, radiative and non-radiative recombinations. The phase dynamics is slower and is affected by thermal redistribution of carriers within the dot. We explain the ultrafast response of quantum dot amplifiers as an effect of hole escape and recombination without the need to assume Auger processes.