基于FPGA的高速数据传输系统设计与实现

为了满足国家重点专项“量子科学实验卫星”中“量子存储板”高速串行数据传输的测试要求,提出了一种以Nios II嵌入式处理器为控制核心,TLK2711、RS422、USB2.0和千兆以太网为传输接口的高速数据传输解决方案;系统采用TLK2711完成高速数据的串并转换,采用RS422完成命令和控制信号的传输,实现与“量子存储板”的高速数据传输;利用Xilinx公司Zynq-7000芯片独有的ARM+FPGA架构实现千兆以太网完成数据的高速传输,利用EXAR公司XR21V1414 USB转串口芯片实现命令、遥测等数据的传输;采用Labview编写上位机控制整个系统的运行,实现命令发送、指令解析、运行状态显示、数据帧产生、高速数据传输、解析和存储等功能;实测结果表明,此系统数据传输速率高达600 Mbps,满足高速串行数据传输的要求,且具有稳定性高、可靠性好等优点。     

矢量贝塞尔涡旋波束在均匀单轴各向异性介质中的传输

基于电磁场的矢量波函数展开方法和不同坐标系中矢量波函数转化关系,得到了圆对称矢量贝塞尔涡旋波束的圆柱矢量波函数展开系数;结合电磁场边界条件,获得了圆对称矢量贝塞尔涡旋波束以任意方向照射均匀单轴各向异性介质层的反射场、透射场和内部场的展开系数;数值计算了沿波束传播方向横截面上的入射、反射和透射电场强度分布以及xOz平面内传播路径方向的总电场强度分布。结果表明,圆对称贝塞尔涡旋波束入射单轴各向异性介质的反射场基本保持同心圆环结构,但强度分布不再呈圆对称;透射场出现两束交错折射光,总电场强度轮廓显著扭曲。     

海神单胞菌属的基因组测序数据分析

海神单胞菌属(Neptunomonas)于1999年被首次鉴定,目前包含8个菌种,其中6个已经完成全基因组测序。本文总结了海神单胞菌属的菌种特征和基因组信息,并利用基因组测序数据对该菌属的碳源利用途径、聚羟基脂肪酸酯代谢途径和芳香族化合物降解途径进行了分析。研究发现,海神单胞菌属具有完整的糖酵解和乙酸利用途径,普遍含有Ⅰ型和Ⅲ型的聚羟基脂肪酸酯合成酶,存在芳香族化合物的降解途径。基因组测序数据分析结果可以为海神单胞菌属在聚羟基脂肪酸酯合成与环境治理保护等领域的应用提供理论依据。     

绳索长度误差对索网天线网面精度影响的分析方法

为分析绳索长度制造误差对索网天线网面精度的影响,提出了一种整体坐标迭代算法.该算法模拟了索网结构的自由节点在考虑绳索随机长度误差后向其他平衡状态运动的过程.分别使用该算法和有限元法分析了一个环形桁架天线计算模型,并将这两种算法的计算结果做了对比,验证了该算法的正确性、可行性和有效性.使用整体坐标迭代法分析了不同的误差分布、绳索长度公差和绳索预张力对网面精度的影响,并对网面综合误差与绳索长度误差、绳索预张力的关系进行了拟合分析,得到了满足工程需求的拟合关系式.     

我国聚羟基脂肪酸酯产业链的发展概况

聚羟基脂肪酸酯(PHA)是一类微生物合成的结构多样的高分子生物聚酯,具有生物可再生性、生物可降解性和良好的生物相容性,应用前景广阔.本文从PHA的材料学性质、发酵生产、提取工艺、应用前景以及我国PHA产业现状等多个方面,综述了基于PHA的产业链的相关生产和研究进展.     

Reflection and transmission of Laguerre Gaussian beam from uniaxial anisotropic multilayered media

Based on angular spectrum expansion and 4 × 4 matrix theory, the reflection and transmission characteristics of a Laguerre Gaussian(LG) beam from uniaxial anisotropic multilayered media are studied. The reflected and transmitted beam fields of an LG beam are derived. In the case where the principal coordinates of the uniaxial anisotropic media coincide with the global coordinates, the reflected and transmitted beam intensities from a uniaxial anisotropic slab and three-layered media are numerically simulated. It is shown that the reflected intensity components of the incident beam, especially the TM polarized incident beam, are smaller than the transmitted intensity components. The distortion of the reflected intensity component is more evident than that of the transmitted intensity component. The distortion of intensity distribution is greatly affected by the dielectric tensor and the thickness of anisotropic media. We finally extend the application of the method to general anisotropic multilayered media.     

优化条件下过氧化氢降解壳聚糖的光谱学研究

在最佳反应条件下制备过氧化氢对壳聚糖的降解产物,通过测定原料及降解产物(Mw=1 500～166.53 kDa)的氮、碳含量,分析它们的红外光谱、核磁共振碳谱、X射线衍射谱及圆二色谱,考察各产物是否保持其天然结构。结果表明：各降解产物与原料的碳含量,氮含量及脱乙酰度的最大相对偏差分别为2.4%,2.3%与6.9%,且后两者随着反应时间的延长而减小;各降解样品的红外光谱及核磁共振碳谱与原料壳聚糖的相似,说明降解过程几乎不改变原料的化学结构;经相同方法处理过的原料及降解产物在2θ=10.4°和19.8°处均存在X射线衍射峰,在210 nm处均存在一个负的圆二吸收峰,表明产物的固态结构与其在溶液中的构象均没有发生变化。说明在优化的降解条件下过氧化氢氧化降解没有改变壳聚糖的天然结构。     

乳酸菌乳饮料生产的关键技术

乳酸菌乳饮料是利用牛乳等原料经过发酵、调配而成的一种保健食品,已经越来越受到国内消费者的青睐.高质量乳酸菌乳饮料的生产重点在于前期酸乳的发酵,这方面对于人员、生产设备、原辅材料、生产环境和生产技术等有着较高的要求.该文从原辅材料、生产设备、发酵剂、生产工艺和卫生控制等方面分析了乳酸菌乳饮料生产中的一些关键技术,可以作为乳酸菌乳饮料生产企业和技术人员的参考.     

Scattering and propagation of terahertz pulses in random soot aggregate systems

Scattering and propagation of terahertz pulses in random soot aggregate systems are studied by using the generalized multi-particle Mie-solution(GMM) and the pulse propagation theory. Soot aggregates are obtained by the diffusion-limited aggregation(DLA) model. For a soot aggregate in soot aggregate systems, scattering characteristics are analyzed by using the GMM. Scattering intensities versus scattering angles are given. The effects of different positions of the aggregate on the scattering intensities, scattering cross sections, extinction cross sections, and absorption cross sections are computed and compared. Based on pulse propagation in random media, the transmission of terahertz pulses in random soot aggregate systems is determined by the two-frequency mutual coherence function. Numerical simulations and analysis are given for terahertz pulses(0.7956 THz).     

Relation between Debye series and generalized Lorentz--Mie theory of laser beam scattering by multilayer cylinder

With the recursive relations of Bessel function and applying inductive approach, the consistency between the scattering coefficient formula of Debye series and that of the generalized Lorentz-Mie theory (GLMT) in the scattering of a multilayer cylinder illuminated by a laser beam is proved in detail. As an application example, rainbow phenomenon in the scattering of a two-layer cylinder is discussed by the Debye series components. It can be concluded that the radius and the refractive index of a two-layer cylinder have an effect on the twin-primary rainbow, and the high-order Debye series components which are associated with the high-order rainbows are more complex than those of a homogeneous cylinder.