圆二色光谱及其在药物研究方面的应用

对圆二色光谱技术在手性化合物分析中的应用进展进行综述,简单介绍了圆二色光谱的原理和特点,着重阐述了圆二色光谱在药物研究领域中的应用,初步探讨了HPLC-CD联用在该领域的应用.     

基于交错并联控制的Boost电路的优化方法

文章主要提出了一种交错并联Boost电路的设计方法,包括了电流采样电路的设计,均流电路的设计,Interleave相位的锁相控制, 建立功率转换系统Boost变换器状态空间方程,求得小信号模型和电压电流开环传递函数,设计合理的补偿环节,获得良好的稳态和动态性能;并进行了实验验证;文章的设计方法能够有效减小boost模块的输出电流纹波和开关管的电流应力,提高了系统的稳定性和可靠性,而且系统动态性能得到很好的改善。     

基于激光拍频高准确度相位式测距方法

介绍一种基于相位式激光测距的高动态、高准确度测距系统.系统引入光频调制技术实现激光拍频产生高频调制信号并完成信号的高速变测尺调制.在对回波信号进行鉴相时,为降低鉴相偏差采用无窗全相位谱分析并实现对测量信号的相位计算.计算表明,该方法可以有效抑制频谱泄露,减小噪声对测量结果的影响,提高鉴相准确度.实验表明该测距系统可以有效地解决相位法测距中存在的抗干扰能力差、距离模糊较难抑制等问题,调制信号频率为100 MHz、信噪比为30dB时测距准确度优于0.5mm.     

十亿像素瞬态成像系统实时图像拼接

为了满足工程应用对图像拼接实时性的要求,依据已设计完成的基于同心球透镜与微相机拼接阵列复合结构的十亿像素瞬态成像系统,提出一种基于统一计算设备架构(CUDA)与先验信息相结合的自适应图像拼接并行加速算法。首先,利用高精度四维标定平台对相邻微相机成像重叠区域进行预标定。接着,采用基于CUDA的快速鲁棒特征(SURF)方法检测提取重叠区域图像的候选特征点集。然后,运用基本线性代数运算子程序(CUBLAS)加速基于随机KD-Tree索引的近似最近邻搜索(ANN)算法,用于获取初始匹配点对。最后,提出一种改进的并行渐近式抽样一致性(IPROSAC)算法,用于剔除误匹配点对和空间变换矩阵的参数估计,从而得到拼接图像的空间几何变换关系。实验结果表明,该算法的图像拼接时间为287 ms,与单独采用CPU串行算法相比速度提高了近30倍。     

Measurement of electronegativity during the E to H mode transition in a radio frequency inductively coupled Ar/O_2 plasma

This paper presents the evolution of the electronegativity with the applied power during the E to H mode transition in a radio frequency(rf)inductively coupled plasma(ICP)in a mixture of Ar and O2.The densities of the negative ion and the electron,as well as their ratio,i.e.,the electronegativity,are measured as a function of the applied power by laser photo-detachment combined with a microwave resonance probe,under different pressures and O2 contents.Meanwhile,the optical emission intensities at Ar 750.4 nm and O 844.6 nm are monitored via a spectrograph.It was found that by increasing the applied power,the electron density and the optical emission intensity show a similar trench,i.e.,they increase abruptly at a threshold power,suggesting that the E to H mode transition occurs.With the increase of the pressure,the negative ion density presents opposite trends in the E-mode and the H-mode,which is related to the difference of the electron density and energy for the two modes.The emission intensities of Ar 750.4 nm and O 844.6 nm monotonously decrease with increasing the pressure or the O2 content,indicating that the density of high-energy electrons,which can excite atoms,is monotonically decreased.This leads to an increase of the negative ion density in the H-mode with increasing the pressure.Besides,as the applied power is increased,the electronegativity shows an abrupt drop during the E-to H-mode transition.     

一种具有异常透射功能的新型惠更斯超表面

提出了一种具有独立调控透射幅值与相位能力的新型惠更斯单元结构,能够实现透射幅值在0～0.9、透射相位在0～2π的任意调控.基于广义斯涅耳定理对惠更斯单元进行排列,设计并制备出具有异常透射功能的超表面结构.全波仿真结果表明超表面能够使频率为10 GHz的正入射电磁波产生约60°的偏折.近场测试结果与仿真结果基本一致,进一...