分布耦合系数对线性啁啾光栅色散的影响

本文从光栅反向耦合波方程出发,经相位共轭变换用Runge-Kuta-Gil方法对其数值求解。针对线性啁啾光栅耦合系数变化服从不同的分布,分析了各种分布对光栅反射谱特性和色散特性的影响。     

基于遗传算法的同步感应线圈发射装置参数优化

发射速度和能量转换效率是同步感应线圈型电磁发射装置（SICEML）最重要的两项指标。驱动线圈和电枢的结构参数、驱动线圈匝数以及电枢初始触发位置都会对这两项指标产生影响。以上述参数为变量,以发射速度和能量转换效率之积为目标函数,引入遗传算法对单级SICEML参数进行了优化设计,并利用有限元软件进行了仿真验证。结果表明：在储能与发射装置总体体积不变的前提下,优化后的系统效率由5.38%提高到13.6%,出口速度由38 m/s提高到61 m/s,系统性能得到明显改善。利用单级SICEML样机进行了堵驻试验,结果与仿真结果吻合较好,验证了本文提出的遗传算法的可行性。     

单摆周期的系统误差分析

文章逐个分析计算了单摆的摆角、摆球的自转、摆线质量、空气浮力以及空气阻力对于单摆周期的影响,以1 m长5°小幅单摆为例,得到这5种因素带来的系统相对误差分别为+0.45‰、+0.02‰、-0.45‰、+0.07‰、-0.14‰,合计仅为-0.05‰,即这5种误差因素几乎相互抵消,小幅单摆实验在理论上的系统误差极小.文章给出了较为详细的推理、计算和分析过程,尤其空气阻力矩的推理过程以及图、表等,意在提供较为完整和准确的认识.文末,针对人们在空气阻力认识上可能存在的某些不足,文章给出了几点必要的说明.     

Optimal Scheduling Algorithms of System Chip Power Density Based on Network on Chip

Russian Physics Journal - The improvement of chip integration leads to the increase of power density of system chips, which leads to the overheating of system chips. When dispatching the power...     

晶界内耗的研究

晶界内耗是中国科学家葛庭燧开创的一个研究领域．以往晶界内耗的研究主要是用多晶试样进行的．最近作者用不同取向差的双晶试样研究了单个晶界的内耗，取得了一些新的结果．文章综述了研究晶界内耗的意义以及新近的进展．     

一种城市路灯合理排布的优化设计方法

文章借助于物理模型和数学计算分析，给出了一种优化的城市路灯排列的设计方法．利用该方法优化出的路灯排列方式（如三角型排列），与现在普遍采用的对称排列方式相比，可以在满足人们交通安全和正常工作生活的条件下，达到节省电力能源的效果；或者是在能源耗费相同的条件下，能提供更高、更均匀的照明度．     

Reaction mechanism studies for platinum nanoparticle growth by atomic layer deposition

Mass spectrometry is used to study the reaction mechanism of platinum (Pt) atomic layer deposition (ALD) on large quantities of high surface area silica gel particles in a fluidized bed reactor. (Methylcyclopentadienyl)trimethylplatinum [(MeCp)PtMe₃] and oxygen are used as precursors. Studies are conducted at a substrate temperature of 320 °C. The self-limiting behavior of ALD appears to be disrupted with overexposure of Pt precursor. The amount of the deposited Pt and the size of the Pt nanoparticles increase with an increasing overdose time of Pt precursor. This can be explained by the thermal decomposition of Pt precursor at the reaction temperature of 320 °C and the in situ sintering of Pt nanoparticles forming larger particles. This finding is significant and its understanding is essential for better control of Pt deposition to achieve desirable morphological and structural properties for different application requirements.     

Lifetimes of High Spin States in an Odd-Proton Nucleus 129Cs

Lifetimes of high spin states in 129Cs axe measured using the Doppler shift attenuation method. The high spin states of 129 Cs axe populated following the fusion evaporation reaction 124 Sn（UB, 6n）129 Cs at a beam energy of 65 MeV. The reduced transition probabilities B（E2） and the transition quadrupole moments Qt in the negativeand positive-paxity bands are deduced. The experimental results indicate that the Qt values of the negative parity band are smaller than those of the positive parity bands, probably due to different γ-deformation driving effects of different proton orbitals. The Qt values exhibit a considerable increase near the band crossing region in these bands. This behavior demonstrates that nuclear shape changing results from the neutron or proton alignments. The signature splitting of the πh11/2 and πg7/2 bands shows the opposite changing trend after backbending due to the h11~2 neutron and h11/2 proton alignments, respectively.     

A volume resolution phantom for MRI

Multisite quantitative magnetic resonance imaging (qMRI) of volume requires a small isotropic point spread-function (PSF) that is spatially, temporarily, and platform invariant. A phantom which will allow rapid assessment of this metric throughout the imaged volume without repositioning will assist certification of imaging sites for use in qMRI studies based on volume. This paper presents a phantom design for this purpose with a three-dimensional repeating pattern throughout its 800-cm³ volume. The image of the pattern from the phantom contains a series of positive signal points and lines which can be used to measure the PSF, gradient linearity, gradient orthogonality, and B₀ homogeneity at multiple locations throughout its volume. The phantom is readily constructed, can be filled with any nuclear magnetic resonance signal-bearing liquid, and the design is scalable to cover larger volumes.     

光互连中二元计算全息算法的研究

二元计算全息(BCGH)是光学信息处理中一个重要元件,其在动态光互连中被广泛使用.为了更好地在光互连中应用BCGH,本文设计改进了二元计算全息的选代算法,比较了几种内能函数下的迭代算法所设计的BCGH,对其象质的不同指标进行了分析.结果表明,用迭代搜索算法是光互连应用中设计BCGH的一种较理想算法.