云计算的蚕豆虫害可见-近红外光谱分类

利用蚕豆叶片可见-近红外反射光谱结合导数光谱对健康、少量、大量虫害三种等级的实验样本进行光谱特征分析,并选择虫害检测最优波段。采用Hadoop,Spark和VMWare虚拟机搭建云计算平台,使用MLlib机器学习库实现人工神经网络(ANN)和支持向量机(SVM)分类算法,并对三种等级蚕豆叶片全波段和最优波段光谱进行分类建模与预测。结果表明ANN虫害光谱分类模型准确率优于SVM虫害光谱分类模型,并且在云平台上运行效率更高,同时全光谱波段的预测准确性高于最优波段。通过扩展光谱数据集,云计算技术在光谱数据挖掘中的计算效率有显著提升。云计算分类检测可以为作物生物胁迫光谱识别提供新的技术和方法。     

Electron proton instability in the CSNS ring

The electron proton (e-p) instability has been observed in many proton accelerators. It will induce transverse beam size blow-up, cause beam loss and restrict the machine performance. Much research work has been done on the causes, dynamics and cures of this instability. A simulation code is developed to study the e-p instability in the ring of the China Spallation Neutron Source (CSNS).     

Fast implementation of matched-filter-based automatic alignment image processing

Video images of laser beams imprinted with distinguishable features are used for alignment of 192 laser beams at the National Ignition Facility (NIF). Algorithms for determining the position of these beams enable control systems to perform the task of alignment. Real world beam images suffer from intensity fluctuation or other distortions, making algorithms susceptible to higher position measurement variability. Using matched filtering to identify beam positions results in greater stability of position measurement compared to centroiding techniques. However, this gain is achieved at the expense of extra processing time. This work explores the use of FPGAs to accelerate these computations. Results indicate a performance improvement of 20 times for an FPGA over a 3 GHz Pentium 4 processor.     

高密度冷原子云辐射陷获效应造成的荧光减弱现象

实验测量了磁光阱的磁场关断之后的荧光变化,观察到几十ms量级的荧光上升过程. 根据实验条件进行分析,在高密度冷原子云中辐射陷获效应造成额外的非相干抽运光场是造成磁光陷阱紧束缚状态下荧光减弱的原因. 同时还进行了简单的数值模拟,结果表明只有考虑到散射光场的频率重分布效应,计算结果方能与实验符合. 关键词： 冷原子云 辐射陷获 频率重分布     

基于内存约束的一维负载平衡方法及其应用

在内存约束的条件下,提出一种新的一维负载平衡方法.该方法是一个迭代法,严格的理论证明表明,它可以线性收敛到最优剖分.针对典型的负载不平衡模型和三维分子动力学问题,1024个处理器上的实际应用表明,该方法可以取得较好的效果.     

氢原子电子云空间分布的可视化

利用Matlab实现了氢原子电子云空间分布的可视化,输入任一组满足取值条件的量子数n、l、m,可同时给出该状态下氢原子径向几率密度曲线、角向几率密度曲线、三维空间几率分布以及三维空间等几率面,便于多视角地理解氢原子电子云的空间分布．     

光学向量-矩阵乘法器教学演示实验

为了在光计算教学中提供让学生更易于形象理解光的并行计算能力和实现方式的教学环境,基于向量-矩阵乘法的基本原理,采用LED阵列、光敏管阵列、柱面透镜、薄透镜等简易的基础光学元件搭建了4×4的光学向量-矩阵乘法器教学演示实验.该演示实验展示了并行光计算系统的基本功能实现和构成要素,有助于学生对光计算有初步的形象认识和了解,认知本课程的目的和意义,有利于激发学生对课程学习的兴趣.     

小波分析在灰度遥感图像去云中的应用

针对薄云覆盖的灰度遥感图像其清晰度低、难于判读地物信息等问题, 提出了小波分析方法用于灰度遥感图像去云。以256 pixel×256 pixel的灰度遥感图像为例, 进行1～8级分解, 重构时对细节系数放大1～10倍, 先选定小波函数确定图像信息熵取得最高时的分解级数为7和相应细节系数的放大倍数, 再确定双正交2.2型小波和离散近似Mery小波, 以0.1为步长的细节放大倍数作进一步分析。结果表明, 分解的级数较低时, 图像信息熵对细节系数放大倍数的依赖性很强; 放大倍数为1.1时得到的图像其信息熵取得极大值; 采用离散近似Mery小波, 当放大倍数为4.8和5.7时还出现2个峰值。     

Experimental investigations of hypervelocity impact onto aluminium dual-plate structure

Dual-plate structure is very effective in the protection of space vehicle from hypervelocity impact. The experiments of Al projectile impacting Al dual targets at the velocity ranging over 2.5–7.0 km/s were systematically conducted. The damage effects were examined, including the perforation of the shield, the development of debris cloud and the general damage characteristics of the subplate. Many valuable experimental data and phenomena have been obtained     

Intramolecular Hamiltonian logic gates

An intramolecular computing model is presented that is based on the quantum time evolution of a single molecule driven by the preparation of a non-stationary single-electron state. In our scheme, the input bits are encoded into the coupling constants of the Hamiltonian that governs the molecular quantum dynamics. The results of the computation are obtained by carrying out a quantum measurement on the molecule. We design reliable , , and logic gates. This opens new avenues for the design of more complex logic circuits at a single-molecular scale.