Organic field-effect transistors based on Langmuir–Blodgett films of substituted phthalocyanines

Three substituted phthalocyanines (Pcs), two asymmetrical and one symmetrical, named amino-tri-tert-butyl-phthalocyanine (AmBuPc), 1,8-naphthalimide-tri-tert-butyl-phthalocyanine (NaBuPc), and tetra-iso-propoxy-phthalocyaninato copper(II) (i-Pro-CuPc), were used as semiconductor layers in organic field-effect transistors (OFETs) based on their Langmuir–Blodgett (LB) films. These substituted Pcs possess good solubility in common organic solvents. From the long-wavelength absorption edge of their UV–VIS absorption spectra and their electrochemical data, the highest occupied molecular orbital and the lowest unoccupied molecular orbital were determined and the energy band diagram of their OFETs was deduced. The narrower energy gaps of them indicated stronger electron donor–acceptor ability than other symmetrical Pcs because of the substituents at the peripheral ring. The results of their OFETs demonstrated that the LB films of these substituted Pcs can be used as semiconducting layers of OFETs functioned as p-channel accumulation devices. From the electrical characteristics of their OFETs, the channel carrier mobilities of AmBuPc, NaBuPc and i-Pro-CuPc were calculated to be about 2.84×10⁻⁵, 4.42×10⁻⁴ and 3.25×10⁻⁴ cm² V⁻¹ s⁻¹, respectively.     

碱性品红薄膜光波导传感元件检测二氧化硫气体的研究

该文利用碱性品红薄膜作为光波导传感元件的敏感层,研制出了一种玻璃光波导酸性气体传感元件,将该元件固定在光波导气体检测系统,检测了SO2气体.该气体传感元件能够检测浓度为5×10-7(体积分数)的SO2气体,其响应和恢复时间分别为3s和8s,相同浓度的其它酸性气体对检测SO2气体干扰较小.该传感元件具有响应快、可逆性好、容易制备等特点.     

Nanocomposite based on a liquid crystal doped with aluminum nitride nanotubes for optical sensor of sulfur dioxide

It has been demonstrated the possibilities of designing the material for optical sensor primary transducer. The nanocomposites based on a cholesteric liquid crystal with aluminum nitride for material of primary transducer of sulfur dioxide optical sensor were studied. The spectral characteristics of studied nanocomposite under the influence of sulfur dioxide were studied. The shift of central wavelength of selective reflection under the sulfur dioxide concentrations was observed.     

一种基于感声波纹结构的光学式声传感器

设计了一种基于硅MEMS敏感结构的光学式声传感器,其光学调制原理采用强度调制型,微敏感结构采用具有低应力波纹结构的感声薄膜芯片。对光纤与微敏感结构耦合技术进行实验研究,优化光学参数,并制作传感器样品。经实验测试,灵敏度达80mV/Pa。     

基于双核酞菁铜为中性载体的水杨酸根选择性电极的研究

合成了一种双核酞菁铜的衍生物,并将其用于离子选择性电极的敏感材料,制备出了基于该载体的水杨酸根离子(Sal-)选择性电极.该电极对Sal-呈现出良好的选择性和近能斯特电位响应性能.电极斜率为-56.5 mV/dec,线性范围为1.0×10-1～2.2×10-6mol/L,检测下限8.9×10-7mol/L.该电极用于了阿司匹林药片中水杨酸含量的分析,结果令人满意.     

基于偏磁薄膜矫正的直流光学电流传感器设计

针对高压输电中直流的检测,提出一种基于偏磁薄膜矫正的直流光学电流传感器.偏磁薄膜固定磁场在石榴石材料中的方向提高了传感器测量精度,采用偏振计直接检测偏振角的方法消除了偏振面预偏角度误差对测量系统的影响.对传感器实现直流检测进行理论分析,设计了传感器的光路结构,并使用传感器进行直流检测实验.结果表明：该传感器能兼顾灵敏度和测量范围的需要且测量输出线性度高,线性拟合度为0.999 53,多次测量重复性好,误差小于0.4％.     

Gas sensing properties of the composite Langmuir–Blodgett films: effects of the film thickness and the Cd addition into the subphase

It was discovered in the previous studies that the kinetic response of NO sensors based on copper tetra-tert-butyl phthalocyanine (CuTTBPc) Langmuir–Blodgett films (LB films) could be greatly improved if CuTTBPc mixed with arachidic acid (AA) in optimized molar ratios was used instead of the phthalocyanine derivative alone. In this paper we investigate the effects of the film thickness and the ionic content of the subphase on gas-sensitive properties of CuTTBPc:AA (1:1 molar ratio) LB films with respect to NO. It was shown that both the sensitivity and the kinetic response of the LB films were influenced by the Cd²⁺ addition into the subphase. These distinctions, being rather small for the thinnest films, became much more pronounced for thicker ones. If “pure” water was used as a subphase, experimental data could be explained mainly by the gas diffusion into the film bulk whereas the surface adsorption was a predominant process in the case of the Cd²⁺-containing subphase. Obtained results are discussed as regards the sensor performance optimization.     

An optical tactile sensor for manipulators

A touch sensor for robots was designed, built and demonstrated. It is based on a deformable elastic reflective surface and optical fiber technology. The device is relatively immune to electromagnetic noise and may be used in environments where it is important to protect sensitive electronic equipment from such noise. The sensed touch pattern is easily read and interpreted by a computer using current video technology. The design allows for extremely high spatial resolution (2100 sensitive spots per square inch achieved here). Spatial resolution must be traded off with sensor pad thickness to retain adequate sensitivity.     

Simultaneous determination of lead and cadmium at a glassy carbon electrode modified with Langmuir–Blodgett film of p-tert-butylthiacalix[4]arene

A glassy carbon electrode (GCE) modified with a Langmuir–Blodgett (LB) film of p-tert-butylthiacalix[4]arene (TCA) has been investigated as a disposable sensor for measuring the trace levels of lead and cadmium. The possibility of determining lead and cadmium at trace levels was examined with differential pulse stripping voltammetry in the measurement step. The electrochemical response was characterized with respect to supporting electrolyte, pH of solution, accumulation time, accumulation potential, layers of the LB films, and possible interferences. Calibration plots were found to be linear in the range 2 × 10⁻⁷ to 5 × 10⁻⁵ mol l⁻¹ (Cd²⁺) and 1 × 10⁻⁷ to 2.5 × 10⁻⁵ mol l⁻¹ (Pb²⁺); the detection limits were 2 × 10⁻⁸ mol l⁻¹ (Cd²⁺) and 8 × 10⁻⁹ mol l⁻¹ (Pb²⁺). Possible recognition mechanism was also discussed. From the analysis of real samples (river, lake and tap water) it can be concluded that the method is sensitive and reproducible in determining of these elements and can be used in the analysis of natural water samples.     

基于迈克尔逊干涉原理的光纤传感器简述

摘要：从基于迈克尔逊干涉原理的光纤迈克尔逊干涉仪出发,介绍了光纤迈克尔逊干涉仪系统原理,并分析了干涉仪的工作原理。在此基础上,针对一些对仪器产生影响的问题提出简略的解决方法,同时阐述了此系统的优点以及应用。     

Development of an optical fibre reflectance sensor for copper (II) detection based on immobilised salicylic acid

Immobilized salicylic acid onto XAD-2 (styrene–divinylbenzene cross-linked copolymer) has been attempted in this study as a reagent phase for the development of an optical fibre copper (II) sensor. The measurements were carried out at a given wavelength of 690.27 nm since it yielded the largest divergence different in reflectance spectra before and after reaction with the analyte element. The optimum response was obtained at pH 5.0. The linear dynamic range of Cu(II) was found within the concentration range of 1.0–2.0 mmol L⁻¹ with its LOD of 0.5 mmol L⁻¹. The sensor response from different probes (n = 9) gave an R.S.D. of 8.4% at 0.55 mmol L⁻¹ Cu(II). The effect of interfered ions at 1:1 molar ratio of Cu(II):foreign ion was also studied in this work.     

基于光纤法布里-珀罗干涉仪的温度传感器

提出了一种基于光纤法布里-珀罗(F-P)干涉仪的温度传感器,传感器的敏感部分是一段两端研磨为平面的单模光纤,它的一端与一根单模传光光纤相接以形成一个反射面,另一端与空气接触形成另一个反射面,这两个反射面与敏感部分光纤形成本征光纤F-P干涉仪(IFPI).分析了该光纤温度传感器的温度响应特性,制作了传感器原理样机,搭建了测试平台,并对原理样机进行了测试.在25 ～30℃的范围内对传感器进行了标定,测得温度响应灵敏度为21.504·2πrad/℃,温度分辨率为0.046℃.实验结果表明:该传感器对温度有较好的线性响应和较高的灵敏度,且制作工艺简单,成本低,具有良好的应用前景.     

薄膜铂温度传感器多点温度检测系统

酒精生产过程中,需要对蒸馏塔多点温度进行检测。采用新型薄膜铂温度传感器设计了多点温度检测系统,使用正反馈型线性校正电路使输出电压与温度成线性关系,从而提高了检测系统的测量准确度。本系统的特点是电路设计新颖、测温准确度高、实用性强。     

Elaboration and standardization of an optical fibre corrosion sensor based on an electroless deposit of copper

The goal of our present work is to develop and test an optical fibre corrosion sensor (OFCS) fabricated by an electroless copper film deposition onto an optical fibre core within the sensing region. In our case, corrosion monitoring was carried out by two methods: optical and electrochemical methods. The idea consists is to couple these two methods by correlating the parameters describing the optical detection and those which describe the electrochemical corrosion process. This approach, once is carried out, makes it possible to gain more precise information on degradation within hidden parts of metallic structures.     

An optical navigation sensor for micro aerial vehicles

This paper describes a catadioptric microsensor for multidirectional imaging and 3D egomotion computation. Inspired by the wide viewing angle of insects’ compound eyes, we show how to extract egomotion information from spherical images. We demonstrate how reflective surfaces can be used for building a compact, multidirectional eye that enables to collect video from 60% of the full sphere. Some experiments performed on synthetic images (using a ray-tracing environment) are presented to validate the concept. We have called the resulting imaging system SICONS (SIngle Chip Optical Navigation Sensor). SICONS is intended for application in micro unmanned aerial vehicles (micro-UAVs) to develop their perceptive, visual guidance and motive abilities to move within the real world in the same way an insect does.     

Diffractive optical element based sensor for roughness measurement

A roughness sensing system, based on the fringe projection technique, is introduced. Roughness parameters are estimated from the fringe pattern projected on the target. The system employs a new projection unit in which light, coming from a laser diode, is coupled to a fiber optic and then impinges on a diffractive optical element (DOE) to produce sinusoidal fringes. The proposed sensor is simple, small and cheap and its sensitivity is easily adjustable. Fringes generated by the DOE are analyzed by a fast fourier transform (FFT) based algorithm, which can work also on curved surfaces.

Experimental results, obtained on varying spark erosion surface roughness standards, showed the capability of the system to perform roughness measurements with a resolution of about 0.5 μm.     

Surface plasmon resonance sensor based on a single-mode polarization-maintaining optical fiber

A novel wavelength modulation-based fiber-optic surface plasmon resonance (SPR) sensor is reported which utilizes both polarization separation and broad band radiation depolarization in polarization-maintaining fibers to enhance sensor stability. Theoretical analysis of the sensing structure with ideally separated polarizations based on the mode of expansion and propagation method is presented. The effect of polarization cross-coupling was also analyzed in the approximation of an equivalent bulk optic structure. A laboratory prototype of the fiber-optic SPR sensor was characterized in terms of sensitivity and resolution. Experimental results indicate that this fiber-optic SPR sensor is able to resolve refractive index changes as low as 4×10⁻⁶ under moderate fiber deformations.     

硬脂酸复合薄膜光波导传感器检测苯乙烯

利用旋转甩涂法将亚甲基蓝(MB)掺杂的硬脂酸复合薄膜固定在钾离子(K+)交换玻璃光波导表面,研制了MB-硬脂酸复合薄膜/K+交换玻璃光波导传感器,并对挥发性有机物蒸气进行检测。实验结果表明,在室温下该传感器对低浓度的苯乙烯蒸气具有较好的重复性和选择性响应,能够检测到1×10-7(体积分数)的苯乙烯蒸气,其响应和恢复时间分别为12s和28s。该传感器具有灵敏度高、响应-恢复速度快、可逆性好、成本低、容易制作等特点。     

All-optical hydrogen sensor based on a high alloy content palladium thin film

Optical reflectance measurements were performed to determine the hydrogen response characteristics of 20 nm thick Pd_0.6Au_0.4 films. The response time and signal change characteristics were determined as a function of hydrogen concentrations ranging from 0.05% to 4% in a balance of dry CO₂ free air. The detection limit was determined to be 0.05%, with a corresponding response time of 130 s, while at 4% hydrogen concentrations the response time was 5 s at ambient temperatures. A linear decrease of both the signal change and response time was measured within an operating temperature range between 25 °C and 100 °C for a 1% hydrogen in air gas mixture. The sensor response dependence of the Pd_0.6Au_0.4 film with a change in humidity was determined between ambient levels and 95% relative humidity (RH). While the signal change was independent of humidity the response time increased due to water adsorption on the Pd alloy sensing layer. A similar increase in response time was shown for 100 ppm of background CO mixed with 1% hydrogen in nitrogen at room temperature. At an elevated operating temperature of 80 °C, 100 ppm of CO did not affect the sensor response towards 1% hydrogen in a balance of nitrogen. Reliability tests have been performed over a 1-year time period and the sensing specifications have not drifted beyond 2% and 13% of the calibrated signal change and response time, respectively. A response time on the order of seconds and the proven stability of the high alloy content Pd thin film demonstrate the promising attributes of this material for use in an all-optical hydrogen sensor.     

光纤液滴传感器实现汽油溶液的鉴别

光纤液滴传感器是利用光纤来监测液滴的增长过程,通过分析随液滴下降过程而变化的光强变化曲线,获得反映液体的物理、化学性质的“光纤液滴指纹图”的测试系统。本文利用光纤液滴传感器测量了不同型号的汽油溶液,同时测量了不同型号的汽油溶液按比例混合后的液滴指纹图,通过对比分析液滴指纹图可以实现汽油溶液的鉴别。