基于3G-ASCX的小型飞行器异常导航信号检测系统设计

传统方法在异常导航信号信噪比较低时对小型飞行器异常导航信号的检测效果不理想。设计并实现了一种基于3G-ASCX的小型飞行器异常导航信号检测系统,硬件设计时着重于ASCX传感器模块、异常导航信号检测模块、主控基站模块、3G/GPRS传输模块的研究,3G/GPRS传输模块的硬件设计中,通过功耗低体积小的CC1100完成异常导航信号的收发,传输过程中通过芯片STC12C5410AD完成电容的平衡转换,选取了MC3486进行电压的转换,最终实现异常信号数据的安全快速传输;软件设计中,系统软件流程设计及异常导航信号检测模块软件设计,最后进行仿真实验,实验结果证明,相比传统系统,所设计系统检测到的小型飞行器异常导航信号同实际测量的异常导航信号具有较高的匹配度,与实际值相比,误差小于1dB,适合推广使用。     

基于AltiVec技术的PowerPC处理器矢量运算性能测试

基于AltiVec技术的PowerPC处理器,在很多嵌入式信号处理领域已经取代传统的DSP处理器成为信号处理器件的首选。为了评估基于AltiVec技术的PowerPC处理器的矢量运算性能和信号处理能力,选取MPC8641D处理器为硬件测试平台,采用符合VSIPL标准的VSI/Pro Core矢量库和ixlibsav矢量库,通过测试复乘和FFT典型算法不同类型的运算时间,对AltiVec处理单元的矢量运算性能进行了测试评估。通过对测试结果的分析,基于AltiVec技术的PowerPC处理器具备强大的矢量运算处理性能,可以满足嵌入式数字信号处理技术对高性能处理器的需求。     

三级质量-弹簧-阻尼系统的特性分析

利用控制理论中的Lyapunov方法对三级质量-弹簧-阻尼系统进行稳定性分析,并用信号流图对系统的可控性做了讨论,结果表明此系统为不稳定系统。     

Research on improving the accuracy of near infrared non-invasive hemoglobin detection

To optimize the accuracy of near-infrared non-invasive hemoglobin (Hb) clinical detection, high-performance instrument and prepossessing algorithm have been investigated. A near-infrared spectrophotometric system was constructed adopting InGaAs detector array with 16 pixels and plane grating spectrometer to obtain high signal noise ratio (SNR) spectral data. In our experiment, we applied the device independently to collect spectra data from 91 volunteers’ fingertips non-invasively. Two prediction tests were conducted to verify the effects of preprocessing algorithms improving the accuracy of near-infrared Hb detection and exclude the occasionality of satisfactory results in a single trial. Our non-invasive Hb detection methods were based on partial least squares (PLS). In each test, PLS, MSC coupled with PLS, DOSC coupled with PLS, three methods for non-invasive Hb detection, were analyzed respectively. The results of two trials showed that only DOSC & PLS performed excellently in both predictive ability and stability, obviously better than other two methods. Relative RMSEP was 6.16% in predicting test 1, 6.08% in predicting test 2, almost reaching the requirements of clinical application. It indicates that our independent-developed high-performance instrument and the method DOSC coupled with PLS are promising in non-invasive Hb detection clinical application.     

Promotion effect of Pt on a SnO2–WO3 material for NOx sensing

Metal-oxide nanocomposites were prepared over screen-printed gold electrodes to be used as room-temperature NO_x (nitric-oxide (NO) and nitrogen dioxide (NO₂)) sensors. Various weight ratios of SnO₂–WO₃ and Pt loadings were used for NO sensing. The sensing materials were characterized using X-ray diffraction (XRD), transmission electron microscopy (TEM) and BET surface analysis. The NO-sensing results indicated that SnO₂–WO₃ (1:2) was more effective than other materials were. The sensor response (S=resistance of N₂/resistance of NO=R_N2/R_NO) for detecting 1000 ppm of NO at room temperature was 2.6. The response time (T₉₀) and recovery time (TR₉₀) was 40 s and 86 s, respectively. By further loading with 0.5% Pt, the sensor response increased to 3.3. The response and recovery times of 0.5% Pt/SnO₂–WO₃ (1:2) were 40 s and 206 s, respectively. The linearity of the sensor response for a NO concentration range of 10–1000 ppm was 0.9729. A mechanism involving Pt promotion of the SnO₂–WO₃ heterojunction was proposed for NO adsorption, surface reaction, and adsorbed NO₂ desorption.     

Long‐Wavelength Fluorescent Reporters for Monitoring Protein Kinase Activity

In vivo optical imaging must contend with the limitations imposed by the optical window of tissue (600–1000 nm). Although a wide array of fluorophores are available that are visualized in the red and near‐IR region of the spectrum, with the exception of proteases, there are few long wavelength probes for enzymes. This situation poses a particular challenge for studying the intracellular biochemistry of erythrocytes, the high hemoglobin content of which optically obscures subcellular monitoring at wavelengths less than 600 nm. To address this, tunable fluorescent reporters for protein kinase activity were developed. The probing wavelength is preprogrammed by using readily available fluorophores, thereby enabling detection within the optical window of tissue, specifically in the far‐red and near‐IR region. These agents were used to monitor endogenous cAMP‐dependent protein kinase activity in erythrocyte lysates and in intact erythrocytes when using a light‐activatable reporter.     

A novel signal-on fluorescent aptasensor for ochratoxin A detection based on RecJf exonuclease-induced signal amplification

This article describes a simple and homogeneous fluorescent aptasensor for the detection of ochratoxin A (OTA). With its high specificity and simplicity; RecJ_f exonuclease is used to cleave DNA strand of the FAM-aptamer/OTA complex and realize target recycling signal amplification. In order to avoid the loss of reaction system, magnetic beads (MBs) are added only once at the last experimental step. This proposed fluorescent aptasensor showed the higher sensitivity in the range of 0.1–100 ng/mL with LOD of 0.056 ng/mL, and the good selectivity against other interfering toxins. The feasibility of the prepared aptasensor was studied by detecting OTA in spiked liquor and cereal samples. The obtained average recoveries ranged from 92% to 115%. This study provides a promising application with convenience and rapidness in the aptasensor fabrication for food safety analysis.     

Superwetting Patterned Membranes with an Anisotropy/Isotropy Transition: Towards Signal Expression and Liquid Permeation

Superwetting membranes with responsive properties have attracted heightened attention because of their fine‐tunable surface wettability. However, their functional diversity is severely limited by the “black‐or‐white” wettability transition. Herein, we describe a coating strategy to fabricate multifunctional responsive superwetting membranes with SiO₂/octadecylamine patterns. The adjustable patterns in the responsive region are the key factor for functional diversity. Specifically, the coated part of the membrane displayed a superhydrophobicity/superhydrophilicity transition at different pH values, whereas the uncoated part exhibited invariant superhydrophilicity. On the basis of this anisotropy/isotropy transition, the membranes can serve as either responsive permeable membranes or signal‐expression membranes, thus enabling the responsive separation and permeation of liquids with satisfactory separation efficiency (>99.90 %) and flux (ca. 60 L m^?2 h), as well as real‐time liquid signal expression with alterable signals.     

Wavelet transforms in separation science for denoising and peak overlap detection

Wavelet transform is a versatile time‐frequency analysis technique, which allows localization of useful signals in time or space and separates them from noise. The detector output from any analytical instrument is mathematically equivalent to a digital image. Signals obtained in chemical separations that vary in time (e.g., high‐performance liquid chromatography) or space (e.g., planar chromatography) are amenable to wavelet analysis. This article gives an overview of wavelet analysis, and graphically explains all the relevant concepts. Continuous wavelet transform and discrete wavelet transform concepts are pictorially explained along with their chromatographic applications. An example is shown for qualitative peak overlap detection in a noisy chromatogram using continuous wavelet transform. The concept of signal decomposition, denoising, and then signal reconstruction is graphically discussed for discrete wavelet transform. All the digital filters in chromatographic instruments used today potentially broaden and distort narrow peaks. Finally, a low signal‐to‐noise ratio chromatogram is denoised using the procedure. Significant gains (>tenfold) in signal‐to‐noise ratio are shown with wavelet analysis. Peaks that were not initially visible were recovered with good accuracy. Since discrete wavelet transform denoising analysis applies to any detector used in separation science, researchers should strongly consider using wavelets for their research.     

全光纤安防系统模式识别混合编程的实现

介绍了宽域全光纤监控预警系统及光纤扰动信号模式识别算法.利用小波包分解对信号进行分解与重构,并提取各频段内信号分量能量谱作为特征向量;应用综合考虑观测数据和确定性先验知识的BVC-RBF神经网络实现信号分类,提高了网络的泛化能力.利用Matlab引擎、动态链接库(DLL)、组件对象模型(COM)3种混合编程方法将Mat...