The lay-out of the photon collider at the international linear collider

One of the interaction regions at the linear colliders should be compatible both with e ⁺ e ⁻ and γγ, γe modes of operation. In this paper, the differences in requirements and possible design solutions are discussed.      

An adaptive strategy based on linear prediction of queue length to minimize congestion in Barabási-Albert scale-free networks

In this paper, we propose an adaptive strategy based on the linear prediction of queue length to minimize congestion in Barabási-Albert (BA) scale-free networks. This strategy uses local knowledge of traffic conditions and allows nodes to be able to self-coordinate their accepting probability to the incoming packets. We show that the strategy can delay remarkably the onset of congestion and systems avoiding the congestion can benefit from hierarchical organization of accepting rates of nodes. Furthermore, with the increase of prediction orders, we achieve larger values for the critical load together with a smooth transition from free-flow to congestion.     

基于高光谱成像技术的番茄叶片灰霉病早期检测研究

提出了独立软模式法(SIMCA)的番茄叶片灰霉病特征波段图像的提取,并通过多元线性回归法(MLR)提取波段融合图像,通过最小距离法获取番茄灰霉病患病信息的技术路线。利用680～740 nm波段的方差图像和建模能力参数提取的特征波段,并作为输入变量进行MLR分析,在0.5准确率阈值下,准确率均大于99%,说明特征波段可以实现番茄叶片灰霉病的检测,并利用MLR回归系数提取波段融合图像,通过最小距离法获取番茄灰霉病患病信息,结果表明所提出的方法具有很好的预测能力,为番茄灰霉病的早期检测提供了一种新方法,且大大降低了高光谱图像的数据处理时间。     

Study on fast linear scanning for a new laser scanner

In the field of lidar system design, there is a need for laser scanners that offer fast linear scanning, are small size and have small a rotational inertia moment. Currently, laser scanners do not meet the above needs. A new laser scanner based on two amplified piezoelectric actuators is designed in this paper. The laser scanner has small size, high mechanical resonance frequencies and a small rotational inertia moment. The size of the mirror is 20 mm×15 mm. To achieve fast linear scanning performance, an open-loop controller is designed to compensate the hysteresis behavior and to restrain oscillations that are caused by the mechanical resonances of the scanner's mechanical structure. By comparing measured scanning waveforms, nonlinearities and scan line images between the uncontrolled and controlled scanner, it was found that the scanning linearity of linear scanning was improved The open-loop controlled laser scanner realizes linear scanning at 250 Hz with optical scan angle of ±12 mrad.     

A new chaotic Hopfield network with piecewise linear activation function

This paper presents a new chaotic Hopfield network with a piecewise linear activation function. The dynamic of the network is studied by virtue of the bifurcation diagram, Lyapunov exponents spectrum and power spectrum. Numerical simulations show that the network displays chaotic behaviours for some well selected parameters.     

Nature of light scalars through photon-photon collisions

The surprising thing is that arising almost 50 years ago from the linear sigma model(LSM)with spontaneously broken chiral symmetry,the light scalar meson problem has become central in the nonperturbative quantum chromodynamics(QCD)for it has been made clear that LSM could be the low energy realization of QCD.First we review briefly signs of four-quark nature of light scalars.Then we show that the light scalars are produced in the two photon collisions via four-quark transitions in contrast to the classic P wave tensor q(q)mesons that are produced via two-quark transitions γγ→q(q).Thus we get new evidence of the four-quark nature of these states.     

Interplay of local resonances and Bragg band gaps in acoustic waveguides with periodic detuned resonators

This letter is concerned with acoustic wave propagation and transmission in acoustic waveguides with periodically grafted detuned Helmholtz resonators. The interplay of local resonances and Bragg band gaps in such periodic systems is examined. It is shown that, when the resonant frequencies of the resonators are tuned close to a Bragg band gap, the behavior of the Bragg band gap can be affected dramatically. Particularly, by introducing appropriately tuned resonators, the bandwidth of a Bragg band gap can be reduced to zero, leading to a very narrow pass band with great wave attenuation performance near both band edges. The band formation mechanisms of such periodic waveguides are further examined, providing explicit formulae to locate the band edge frequencies of all the band gaps, as well as the conditions to achieve very narrow pass bands in such periodic waveguides.     

BEPCII直线加速器数字延时触发器的设计与实现

针对北京正负电子对撞机II期（BEPC II）直线加速器升级改造过程中束流位置探测器（BPM）电子学对外部触发信号的需求,设计了一台高精度延时控制、上升时间短和参数灵活调节的数字延时触发器。采用FPGA（现场可编程门阵列）作为主控制器展开设计,重点介绍了基于FPGA的边沿检测模块和多通道延时处理模块的设计与仿真,描述了FPGA和驱动电路的设计方案以及在直线加速器上的应用。经测试,延时可调范围4 ns～4 μs,最小步进4 ns,步进误差0.125%;上升时间2 ns,延时抖动135.4 ps。     

Determination of the refractive index of spherical erythrocytes of human blood in the range 0.3–1.2 µm

A proposed procedure for determining the spectral values of the refractive index of spherical erythrocytes of human blood is based on angular light scattering and the use (for one-time scattering) of a multiple regression equation. A theoretical study of the stability of the relationship between the light scattering indicatrix and the refractive index of erythrocytes toward possible variations of their microstructure parameters is performed in order to select the optimal angles. The precision of the proposed method and its sensitivity to indicatrix measurement uncertainties are estimated. __________ Translated from Zhurnal Prikladnoi Spektroskopii Vol. 74, No. 3, pp. 382–386, May–June, 2007.     

基于MATLAB软件对不同偏振光在不同介质中的传播过程的动态模拟

利用MATLAB软件对不同偏振光在真空、各向同性介质、线型各向异性介质以及圆型各向异性介质中的传播过程进行了三维动态模拟,能够加深学生对光的偏振概念以及各种偏振光与不同介质之间相互作用原理的理解。