Trace mercury (II) detection and separation in serum and water samples using a reusable bifunctional fluorescent sensor

In this work, a reusable bifunctional fluorescent sensor for simultaneous detection and separation of trace Hg²⁺ in water and serum, which contains a naphthalimide derivative of 2,6-bis(aminomethyl)pyridine covalently grafted to the surface of silica particles, was developed. Meanwhile, the fluorescence characteristics and the adsorbent properties of the sensor were investigated in detail. This sensor showed a very good linearity (correlation coefficient of R² = 0.9991) in the range 0.1-1 μM of Hg²⁺ with detection limits lower than 6.8 × 10⁻⁹ M. It can also be used as an adsorbent for the removal of mercuric ions from the contaminated aqueous solution. The regeneration of this sensor is very simple, only by modulating the pH value of the aqueous solution. It can be reused at least four cycles. In addition, the present approach has the advantages of rapidity, simplicity, and low cost. We believe that this approach may serve as a foundation for the preparation of practical fluorescent sensor for the rapid detection of Hg²⁺ in aqueous biological and environmental samples.     

Polyglycerol-bound phosphotriesterase enzyme model complexes for detection and hydrolysis of phosphorus species in aqueous solution

Phosphotriesterase models incorporating di(2-picolyl)amino ligands supported by m-xylylene or 2-hydroxy-m-xylylene scaffolds have been tethered to the periphery of a water-soluble hyperbranched polyglycerol (PG). In aqueous solution buffered at pH 7.4, the polymeric complexes of Zn²⁺ are useful receptors for polymeric indicator displacement assays for phosphate and pyrophosphate employing commercial complexometric indicators. Under the same conditions, the Co³⁺ effectively hydrolyze p-nitrophenylphosphate with approximately five orders of magnitude rate enhancement versus uncatalyzed hydrolysis. These systems offer promising results as mixed-metal dual detect-decontaminate materials for organophosphorus toxins under mild, neutral aqueous conditions.     

I-V characteristics of a methanol sensor for direct methanol fuel cell (DMFC) as a function of deposited platinum (Pt) thickness

We have fabricated methanol sensor for monitoring the methanol concentration in direct methanol fuel cells. A thin composite nafion membrane was used as an electrolyte. We have analyzed the I-V characteristic of the fabricated methanol sensor as functions of methanol concentration, catalyst electrode and platinum (Pt) thickness. When we measured the sensor with 10 nm Pt and at 1 V, the current value was 1.30×10⁻⁶, 1.96×10⁻⁶, and 2.80×10⁻⁶ A for three methanol concentration of 1, 2, and 3 M, respectively. And when the methanol concentration was fixed at 2 M, the current value of the fabricated device with Pt of 5, 10 and 15 nm was 3.06×10⁻⁶, 1.96×10⁻⁶, and 1.00×10⁻⁶ A, respectively.     

基于微石英晶振的动态非接触静电力显微测量(EFM)技术

在一台基于微晶振的原子力显微镜的基础上，通过在针式传感器前端细小针尖加入可调交流偏压，获得高分辨率动态非接触静电力显微镜。此装置可以分别利用微小针尖与样品间的范德华力与附加的可调整电力信号，同时获得样品表面微观形貌特征和表面电特性，如表面电荷分布，表面电势等。     

Direct amplitude detection of Zernike modes by computer-generated holographic wavefront sensor: Modeling and simulation

A fast holographic wavefront sensor is proposed using a computer-generated hologram (CGH). This CGH is a multiplexed hologram of different Zernike mode–amplitude combinations, and is designed in such a manner as to get the corresponding spots on the detector according to the presence and strength of a particular aberration. Interference between the aberrated wavefront (with a single mode–amplitude combination) and the Fourier transform of an image with single bright pixel (defined as dot image) is numerically calculated for one hologram. Different mode–amplitude combination and corresponding different positions of bright pixels (dots) are taken to compute various holograms and then all the holograms are multiplexed to get the final hologram. When the aberrated wavefront with a particular mode–amplitude combination is incident onto the multiplexed hologram, the corresponding dot is generated in the Fourier plane. A lens performs the Fourier transform in optical domain and provides the instant detection of amplitude of the respective Zernike mode. The main advantage of the scheme is to avoid the need of any computations, which makes it really fast. The simulation results are presented with the cross-talk analysis for few Zernike terms.     

SnO2：TiO2薄膜氨气敏光纤传感器的研究

本文作者利用ＳｎＯ２：ＴｉＯ２气敏光学薄膜设计制成气敏光纤传感器，并用它测定氨蒸汽浓度，传感器的灵敏范围为１５０￣６０００ｐｐｍ，灵敏度为２００ｐｐｍ。     

MEMS热式风速风向传感器输出性能优化研究

环境测温二极管在工作时受传感器芯片热场影响,常引发MEMS热式风速风向传感器加热电压-风速曲线异常。将其更换为外置测温二极管,并调整其与传感器芯片距离,成功解决了输出曲线异常现象。并在此基础上,优化芯片及外置测温二极管的封装方案,消除了热场的相互干扰和不必要的热损耗,同时保证了外置测温二极管与空气的良好接触。风场测试结果表明,传感器的加热电压-风速曲线变得平滑,且重复性好,风速和风向的测量误差分别在±4%和±4°以内,系统的上电稳定时间大幅缩短至15 s左右。     

确定信号情况下矢量水听器检测及估计性能研究

在某些场合,例如水下定位、编码通信,信号具有确知脉冲信号特性,声源相对于接收器的方位,可以采用矢量水听器处理来获得。对于确知脉冲信号,本文证明了在各向同性噪声场下,参考声压和振速的相关处理器的方向是声源方位的最大似然方位估计,以及方位估计的克拉美-罗界CRB(Cramer-Rao Bound)。给出了计算机的仿真结果。     

双光路光纤探头式浓度检测系统

本文介绍了一种双光纤探头式浓度检测系统的工作原理和结构设计。该系统利用双光路比较电压的测量和单片机控制的数据处理系统进行浓度的实时性测量。实验结果表明，该系统具有精度高、速度快等特点，在浓度测试中具有良好的应用前景。     

光电振动传感技术新进展

光电振动传感器在振动测量领域占有重要地位,概要叙述了光电振动传感器近年来的最新进展。按测量原理分类介绍了相关技术的发展和取得的成果,并对技术趋势做了总结归纳,指出了一些热点方向。