光散射/荧光比率法测定全氟辛烷磺酸

在pH=1.81的Britton Robinson（BR）缓冲溶液中,全氟辛烷磺酸（PFOS）与罗丹明B（RhB）通过静电引力和疏水作用使RhB的光散射增强,荧光发生猝灭。 利用在普通荧光光度计上单次扫描获得的340 nm处的光散射强度（I340）与596 nm处的荧光强度（F596）之比,建立了测定PFOS的光散射/荧光比率法,检出限（3σ）为17 nmol/L。 方法用于环境水样中PFOS的测定,RSD≤4.2%。     

Formation and Characteristics of Acrylonitrile/Urea Inclusion Compound

The formation process and composition of the acrylonitrile/urea inclusion compounds (AN/UIC) with different aging times and AN/urea molar feed ratios are studied by differen-tial scanning calorimetry (DSC) and X-ray diffraction (XRD). It is suggested that DSC candetermine the guest/host ratio and the heat of decomposition. Meanwhile, the guest/host ratio and heat of decomposition are obtained, which are 1.17 and 5361.53 J/mol, respec-tively. It is suggested AN molecules included in urea canal lattice may be packed flat against each other. It is found that the formation of AN/UIC depends on the aging time. XRD results reveal that once AN molecules enter urea lattice, AN/UIC are formed, which possess the final structure. When AN molecules are sufficient, the length of AN molecular arrays in urea canals increases as aging time prolonging until urea tunnels are saturated by AN.     

Flow of micropolar fluid between two orthogonally moving porous disks

The unsteady,laminar,incompressible,and two-dimensional flow of a micropolar fluid between two orthogonally moving porous coaxial disks is considered.The extension of von Karman’s similarity transformations is used to reduce the governing partial differential equations(PDEs) to a set of non-linear coupled ordinary differential equations(ODEs) in the dimensionless form.The analytical solutions are obtained by employing the homotopy analysis method(HAM).The effects of various physical parameters such as the expansion ratio and the permeability Reynolds number on the velocity fields are discussed in detail.     

电子白板系统中参数标定方法的研究

为了避开复杂繁琐的摄像机标定过程,提出了一种基于CCD摄像机的电子白板系统参数标定新方法,实现了开机自动标定系统参数的功能。采用Harris角点检测算法成功提取了参考点的像素坐标,并直接运用射影变换交比不变性,推导出白板边框图像像素距离与实际物理距离的映射关系式,进而获得了摄像机的光心坐标。简要分析影响系统标定精度的因素,并设计出减小标定误差的方案,最后搭建实验平台标定系统参数。实验结果表明:该标定方法实现简单,应用方便,且对于单位长度为1 cm的标定块而言,标定误差小于0.04 cm。     

一种高精度测量坦克炮塔动态转角的方法

坦克炮塔相对底盘转角的测量精度直接决定了稳瞄系统与惯导系统的精度。目前,国内的主战坦克所配备的坦克炮塔,其相对底盘的转角测量装置的测量精度低,仅解决坦克车体的转向问题。针对稳瞄系统与惯导系统对坦克炮塔相对底盘转角的精度要求问题,提出了一种由光电定位系统、机械传动系统和旋转变压器组成的动态高精度测角装置,介绍了其工作原理和工作过程,对该测角装置进行光电自准直标定并对误差进行理论分析,最后通过上车实验证明该测角系统能够满足实际需求。实践证明:该测量系统能够在通电瞬间确认位置,具有绝对零位记忆功能,其测角精度为42。     

星载激光测高仪接收放大器参数的优化设计

为使星载激光测高仪满足测量精度的需求,分析了接收放大器部分的设计原则与要求,对带宽、信噪比、探测灵敏度和放大倍数等主要性能参数进行了理论分析与研究,得到了性能参数的关系和优化的参量。理论结果表明,在激光测高仪测量范围为450 km~650 km,激光脉冲宽度为8 ns~12 ns,工作波长为532 nm与1 064 nm的情况下,对放大器性能参数进行分析计算,可以满足虚警率为1%的星载激光测高仪的设计需求。     

利用同质异位素产额比提取对称能的近似方法

在修改的Fisher模型框架下, 利用同质异位素产额比和结合能方程中对称能系数与温度比率的关联, 可以提取对称能系数与温度的比值。 利用3种不同的近似方法得到了重离子核反应产生丰中子余核的对称能系数与温度比（a_sym/T）,并研究了相关物理量对a_sym/T的影响。结果表明, 库仑能对提取丰中子余核的a_sym/T影响较小,且参考核的选取对a_sym/T的提取也有一定的影响。 In the framework of the modified Fisher model, correlations between the symmetry energy coefficient in semi classical mass formula to temperature (a_sym/T) and the isobaric yield ratio in Heavy ion collisions are established. a_sym/Tof neutron rich fragments are extracted using these correlations. It is found that the Coulomb energy term has little effect on a_sym/T of fragments, while the reference isobars adopted have great influence on the extracted a sym/T of fragments.     

高消光比多偏振态光源系统设计

在现代工程测量中,由于工程的各项技术指标要求越来越高,相应地对光源也提出了更高的要求。依据晶体双折射和晶体相位延迟对光偏振态的影响以及光的折射角与光振动方向有关的原理,设计了高消光比多偏振态光源系统,并设计测试方案对该系统实现的偏振态和消光比进行了验证。该光源系统通过计算机精密控制电机旋转设计的转盘结构很方便快捷地实现了S偏振态、P偏振态和圆偏振光的输出,并且系统中设计了平移和旋转装置自动控制偏振棱镜,获得了高消光比的偏振光,出射光消光比小于等于510-6。     

润滑薄油膜承载力的测量

利用面接触润滑油膜测量系统研究了固定倾角滑块轴承承载力问题.在滑块倾角和载荷固定不变的条件下测得油膜厚度与速度的关系,经过参数转换,得到无量纲承载量曲线.这不同于传统方法中在不同收敛比下对油膜压力的直接测量.结果表明:在薄油膜条件下实际承载量曲线和理论曲线表现了相同的变化趋势;实测值小于理论值;理论认为无量纲承载量唯一由收敛比决定,而实验结果表明无量纲承载量曲线受滑块倾角、载荷和润滑油性质的影响.     

Exclusive Semi-leptonic Decays b→s(d)ν\bar{ν} in the Standard Model with Fourth Generation

We consider the effects of the fourth generation quarks on the rareBdecay processes described by the b→ s(d)ν \bar{ν} processes at the quark level. We find that the values of the branching ratios for some of these rare decay processes are much larger than the standard model (SM) predictions.
These processes can be used to constrain the relevant free parameters.