微分约束方法在求解二阶流体精确解上的应用

利用微分约束方法研究了二阶流体的精确解,通过使用一阶微分约束条件,不仅获得了具有抽吸作用下的Couette和Poiseuille平行流、碰撞射流、平面拉伸流等具有明确物理意义的流动解,而且获得了两类新的精确解,所得精确解表明二阶流体的流动特性不仅依赖于物质粘性参数,而且依赖物质弹性参数.此外讨论了部分边值问题.     

机载多环架光电吊舱伺服控制电机的力矩估算

采用多环架稳定的机栽光电吊舱,需要科学准确地估算各环架伺服控制电机的力矩,选择满足控制精度和安装要求的控制电机。通过分析各种扰动作用的途径和多环架结构的抑制效果,估算系统实现指标所需要的加速度、速度,综合出各环架控制电机应有的力矩。得到的数据可用于吊舱系统的性能实现和小型化设计。     

羟基吡啶功能化螺吡喃探针检测尿样中柠檬酸的研究

柠檬酸是多种疾病潜在的生物标记物,因此发展对柠檬酸灵敏、专一的快速检测方法势在必行。该文设计合成了一种羟基吡啶功能化水溶性螺吡喃探针,通过在螺吡喃骨架上引入羟基吡啶基团,利用螺吡喃螺碳及羟基的协同作用增强了探针对柠檬酸的结合能力。结果表明,该探针对柠檬酸有选择性响应,并伴随着明显的颜色变化及荧光猝灭。据此建立了尿样中柠檬酸的荧光检测方法,方法线性范围为20～120μmol/L,检出限为1.0μmol/L。人工尿液中柠檬酸的回收率为85.7%～92.2%,相对标准偏差为3.0%～9.2%。该方法具有操作简便、准确及选择性好的优点,在尿样柠檬酸检测中具有良好的应用潜力。     

SPECTRUM OF THE MICROMASER INJECTED WITH Λ-TYPE THREE-LEVEL ATOMS

The spectrum of the micromaser injected with Λ-type three-level atoms is studied. The spectrum has a Lorentzian lineshape and its central frequency has a shift. The effects of various parameters (for example, the atomic center-of-mass velocity, the cavity-length, the one-photon detuning, the ratio of the atomic injection rate to the cavity decay rate and the number of thermal photons) on the linewidth and the frequency shift are examined. The spectrum shows very different features in different velocity regimes, i.e., in the fast-atom regime, in the intermediate-velocity-atom regime, and in the slow-atom regime.     

毛细管柱气相色谱法测定蜜饯中甜蜜素

蜜饯样品与海砂研磨并用水浸取2 h,分取部分滤液加入适量硫酸后用已定量配入内标甲苯的正己烷10 mL萃取,分取后取出正己烷液层进行气相色谱分析.测定中采用Eduity-1毛细管色谱柱及火焰离子化检测器.应用所提出的方法分析了3种蜜饯样品,并用标准加入法测得方法的回收率在96.4%～99.7%之间.     

平面金属介质复合体的负磁化率(英文)

We report a new type of planar metamaterial consisting of a pair of homogeneous parallel plates separated by a thin medium. Strong magnetic response and negative effective permeability are observed in the materials at wavelengths from 6.9 μm to 5.8 μm. The resonant wavelength and the value of the negative permeability can be tuned by varying the structure dimensions. Such planar metamaterials can be easily fabricated with mature thin film technology and are of great potential for device applications.     

Synthesis and characterization of a novel polymer electrolyte based on acrylonitrile/N-[4-(aminosulfonyl)phenyl]acrylamide copolymers

<正>Acrylonitrile/N-[4-(aminosulfonyl)phenyl]acrylamide(AN/ASPAA) copolymers were synthesized and used as a host of lithium ion conducting electrolytes.The composition,molecular weight and molecular weight distribution of AN/ASPAA copolymers were determined,and the influence of copolymer composition on the glass temperature of AN/ASPAA copolymers and the ion conductivity of electrolytes were investigated.The molecular weights of AN/ASPAA copolymers were lower than those of AN and ASPAA homopolymers due to the cross-termination reaction.The glass temperatures of AN/ASPAA copolymers increased as the molar fraction of ASPAA units in copolymers increased.The lithium ion conductivities of the polymer electrolytes increased initially as the molar fraction of ASPAA units in copolymers increased,and a maximum conductivity was achieved when the molar fraction of ASPAA in the copolymer was 16.8%.     

辽河减压渣油-正戊烷体系的相态变化特性

利用RUSKA公司无汞PVT装置,对辽河减压渣油-正戊烷体系的相行为进行了实验观察,测定了辽河渣油-正戊烷体系相态变化的边界线,如液-液相分界线、液-液-气三相区分界线等,绘制了体系的p-t相图;在140℃～190℃,1.0MPa～10.0MPa,溶剂质量比为3.0～6.0的条件下,对体系相特性的变化进行了分析和讨论。在实验条件下,辽河渣油-戊烷体系的p-t相图可以划分为四个区域:单一液相区、液-液两相区、液-液-气三相区、气-液两相区;溶剂质量比对由单一液相区转变为液-液两相分相压力的影响显著,溶剂质量比越大,分相压力越大;但溶剂质量比对液-液-气三相区影响不大。确定了辽河渣油-正戊烷体系溶剂脱沥青过程适宜的操作区域。     

广义LipschitzΦ-增生算子的带误差项的Ishikawa迭代序列的收敛性及应用

在一致光滑Banach空间中,证明了广义LipschitzΦ-增生算子的带误差项的Ishikawa迭代序列强收敛于方程Tx=f的解,其结果改进和扩展了近期许多相关结果.并由此得出了Ishikawa迭代序列稳定性的一些结果.     

基于Curvelet变换的数字水印算法

数字水印技术能起到版权保护的作用,从数字水印的鲁棒性与不可感知性要求出发,介绍了Curvelet变换的多方向、多分辨、带通特点及各层的系数特征,提出了一种基于Curvelet变换和HVS的图像数字水印技术,这种数字水印方法是将数字水印嵌入到原始图像经Curvelet变换后的高频系数构成的矩阵当中.仿真实验表明该算法简单有效,原图像与嵌入水印后图像差异小,水印提取准确,不仅能保证数字水印不可感知性,而且在对嵌入水印图像进行裁剪、加噪、旋转及涂改等攻击后具有较强的鲁棒性.