左氧氟沙星的体内构型转化与同步一阶导数荧光光谱测定的研究*

控制 pH =3 ,用同步一阶导数荧光光谱技术能很好识别和分辨氧氟沙星消旋体的R和S对映体 ,据此建立了两种旋光体同时测定的同步导数荧光光谱法。测定尿样中的对映体含量 ,线性范围为 :0 3 6～ 2 16μg·mL-1(R) ,0 3 6～ 2 89μg·mL-1(S)和 3 16～ 3 1 6μg·mL-1(S) ,检测下限 0 3 6μg·mL-1,回收率 95 %～10 4 % ,相对标准偏差 <6 6%。发现在体内S对映体向R对映体的转化。考察了S对映体的药代动力学行为 ,并测定了转化率。     

同步-导数荧光光谱法测定尿样中的痕量氧氟沙星

尿样中内源激素等物质发射强的荧光 ,严重干扰氧氟沙星的测定。经过同步和一阶导数处理 ,很好地分辨了尿样背景和氧氟沙星的荧光信号。据此提出了尿样中痕量氧氟沙星含量测定的同步 导数荧光光谱法。测定样品的线性范围为 :0 36～ 3 6 μg·mL-1,检测限 0 30 μg·mL-1,回收率 10 1%～ 10 3% ,相对标准偏差小于 2 5 %。     

基于广义混沌映射切换的混沌同步保密通信

提出了一种基于广义混沌映射切换的混沌同步保密通信方式.这种通信方式首先构建产生多种混沌序列的广义混沌映射模型,然后在不同时段根据切换策略产生不同混沌序列,在发送端,将信号与混沌载波之和取模运算后再嵌入混沌映射的输入端进行迭代运算以实现调制;在接收端,根据切换协议,用同一个相应的广义混沌映射模型从接收信号中提取混沌载波并进而恢复信息信号.研究结果表明:这种基于广义混沌映射切换的混沌同步通信方式比基于单一混沌系统的保密通信方式具有更强的抗干扰能力,保密性能更好,且实现简单. 关键词： 混沌 混沌映射切换 同步 保密通信     

基于间歇性参数自适应控制的混沌同步

提出了在两个不同参数混沌系统的同步中基于间歇性参数自适应的控制方法.在选择合适的间歇反馈周期N和反馈系数r的情况下,可以获得满意的同步结果.以logistic映射为例进行了计算机模拟.结果表明:适当选取反馈系数r,可以以很小的控制代价实现预定的同步目的. 关键词： 混沌同步 间歇控制 自适应控制     

Synchrotron radiation XRF microprobe investigation of elemental distribution in femoral head slice with osteoporsis

This note deals with the scanning of femoral head slices form both normal and osteoporosis subjects using synchrotron radiation X-ray fluorescence (SRXRF) microprobe technique.the sample preparation and experimental apparatus are described in detail.The quantitative computerized tomography(QCT) of elemental distribution,such as Ca,P,K,Fe,Zn,Sr and Pb in bone slice tissue including cartilage,substantial compact and substantial spongy,is investigated.Combined with the correlation between P,K,Zn,Sr and Ca,the loss way of minerals and the physiological functions of some metal elements in bone are also discussed.     

基于事件触发的时滞Lur’e系统主从同步研究

研究了基于事件触发采样控制的时滞混沌Lur’e系统主从同步问题.首先考虑了系统中包含的传输时滞构造了系统时滞模型.然后,通过构造三重积分项的Lyapunov-Krasovskii泛函,并结合Wirtinger积分不等式和凸组合技术对Lyapunov-Krasovskii泛函的导数进行估计,给出了混沌系统主从同步的充分条件.所提出的事件触发机制应用于主从同步研究中,可以有效地减少采样数据传输,缓解网络带宽压力,提高网络带宽利用率.最后,通过时滞蔡氏电路的数值仿真,验证了所提出同步准则的有效性.     

New method for measuring diesel nozzle orif ice inlet structures based on synchrotron X-ray tomography

Spray behavior is regarded as one of the main factors influencing engine performances, fuel consumption and emissions for diesel engines. Under high injection pressure, diesel spray behaviors are extremely sensitive to the nozzle internal geometries, especially the geometric structures of orifice entrance. Based on the synchrotron radiation X-ray tomography technique, the 3D digital models of nozzle tips can be constructed. A new automatic method is presented to reveal the inlet structures according to these nozzle orifice models. The planes passing through the orifice axis are determined and used to cut the models, and then the corresponding cutting images are applied to measure the inlet chamfer radii around the orifice axis automatically. The orifices of a single-hole nozzle and an eight-hole nozzle are measured according to this method. The results show that this method can automatically measure the orifice inlet chamfer radii around the orifice axis with high precision. The obtained inlet chamfer radius shows the whole profile of the orifice entrance, which is a precise feedback for nozzle designing and manufacturing, and it also provides precise geometrical boundary conditions for the study of spray behaviors.     

Image improvement based on sub-pixel post-integration for a staring imaging system in geostationary orbit

This paper proposes the post-integration technology based on sub-pixel image registration and image fusion to improve the signal-to-noise ratio （SNR） of remote sensing images without motion degradation caused by satellite vibration. A two-dimensional vibration system is set up to simulate satellite disturbance. Image sequences with different exposure times are captured using a high-speed CMOS camera. The displacement plots are compared with the motion data measured by the grating linear encoder. These plots indicate that the accuracy of the registration algorithm is better than 0.1 pixels. The sub-pixel image fusion shows an improvement in image quality, thus indicating that this technology is powerful for staring imaging systems in geostationary orbit.     

Fast synchrotron X-ray tomography study of the packing structures of rods with different aspect ratios

We present a fast synchrotron X-ray tomography study of the packing structures of rods with different aspect ratios. Utilizing the high flux of the X-rays generated from the third-generation synchrotron source, we can complete a high- resolution tomography scan within a short period of time, after which the three-dimensional （3D） packing structure can be obtained for the subsequent structural analysis. The image phase-retrieval procedure has been implemented to enhance the image contrast. We systematically investigated the effects of particle shape and aspect ratio on the structural properties including packing density and contact number. It turns out that large aspect ratio rod packings will have wider distributions of free volume fraction and larger mean contact numbers.     

Pinning sampled-data synchronization for complex networks with probabilistic coupling delay

We deal with the problem of pinning sampled-data synchronization for a complex network with probabilistic time-varying coupling delay. The sampling period considered here is assumed to be less than a given bound. Without using the Kronecker product, a new synchronization error system is constructed by using the property of the random variable and input delay approach. Based on the Lyapunov theory, a delay-dependent pinning sampled-data synchronization criterion is derived in terms of linear matrix inequalities （LMIs） that can be solved effectively by using MATLAB LMI toolbox. Numerical examples are provided to demonstrate the effectiveness of the proposed scheme.