海上溢油遥感探测技术及其应用进展

介绍了海上溢油遥感探测常用的可见光、红外、紫外光学遥感器、微波辐射计、雷达、激光荧光器和油层厚度探测器等几种溢油遥感探测器的探测原理、能力及应用状况。可见光仪器的溢油探测能力非常有限；红外遥感器是有一定探测能力的最为实用的探测器；微波遥感具有全天候的特点，但空间分辨率低，识别能力也有一定的限制；而激光荧光器和油层厚度探测器等激光遥感器则是最有发展前景的一类溢油探测器。通过性能等方面的对比分析以及当前实际应用情况，分析了未来溢油遥感技术的发展趋势。     

Fabrication of micro sensors on a flexible substrate

Flexible micro temperature and humidity sensors on parylene thin films were designed and fabricated using a micro-electro-mechanical-systems (MEMS) process. Based on the principles of the thermistor and the ability of a polymer to absorb moisture, the sensing device comprised gold wire and polyimide film. The flexible micro sensors were patterned between two pieces of parylene thin film that had been etched using O₂ plasma to open the contact pads. The sacrificial Cr spacer layer was removed from the Cr etchant to release the flexible temperature and humidity sensors from the silicon substrate. Au was used to form the sensing electrode of the sensors while Ti formed the adhesion layer between the parylene and Au. The thickness of the device was 7 ± 1 μm, so the sensors attached easily to highly curved surfaces. The sensitivities of the temperature and humidity sensor were 4.81 × 10⁻³ °C⁻¹ and 0.03 pF/%RH, respectively. This work demonstrates the feasibility and compatibility of thin film sensor applications based on flexible parylene. The sensor can be applied to fuel cells or components that must be compressed.     

Spectroscopic characterization of oils yielded from Brazilian offshore basins: Potential applications of remote sensing

Spectroscopy is the basis to detect and characterize offshore hydrocarbon (HC) seeps through optical remote sensing. Diagnostic spectral features of HCs are linked to their chemical composition and fundamental molecular vibrations (SWIR-TIR features), as well as overtones and combinations of these vibrations (VNIR-SWIR). These features allow for the characterization of oil, oil on water and emulsified oil. This work shows the results of lab and field spectral measurements of 17 petroleum samples yielded from key, oil-rich sedimentary basins in Brazil. Measurements comprised reflectance data (VNIR- SWIR), Attenuated Total Reflectance (ATR), Directional Hemispherical Reflectance (DHR), and emissivity data (TIR). These spectra were analyzed by multivariate techniques, such as Principal Components Analysis (PCA) and Partial Least-Square analysis (PLS). The experimental results indicate that for the VNIR-SWIR range: (i) spectral features can be recognized for crude oil, emulsified oil and oil on ocean water; (ii) different oil types can be qualitatively distinguished based on these features (i.e. light or heavy), even considering oil on water; (iii) the same applies for oil measurements simulated at the spectral resolution of hyperspectral (357-bands/ProSpecTIR) and multispectral (9-bands/ASTER) sensors. Within TIR wavelengths (3-14 μm), typical HC spectral features can also be resolved and oil types qualitatively discriminated using PCA/PLS, including both full-resolution spectra and spectra resampled to hyperspectral sensor (128-bands/SEBASS). However, despite the fact that oil emissivity is always lower than that of water, such separation seems unfeasible using 8-12 μm TIR features only; emissivity spectra are essentially flat for all samples in this interval. This research demonstrated that oil can be qualitatively distinguished based on both VNIR-SWIR and TIR spectroscopy data, with important implications for remote off-shore oil exploration and classification of oil leakages.     

海面溢油的可见光波段地物光谱特征研究

通过对试验获得的原油、柴油和润滑油的可见光近红外波段地物光谱特征曲线进行处理、对 比、分析,揭示和总结了3种油随厚度变化的光谱特征、油水反差规律及吸收特征参数:3种油反射 总体趋势是柴油随厚度增加而增大,润滑油和原油随厚度增加而减小。柴油的反射率远高于海水, 润滑油在蓝绿光波段反射率高于海水,而原油与海水反差在蓝绿光波段最低等,可为识别油膜厚 度、区分油膜与海水和鉴别油种提供帮助,从而使通过卫星遥感手段实时监测海面溢油成为可能。     

Embedding conductive patterns of elastomer nanocomposite with the assist of laser ablation

This work introduces a simple and low-cost microfabrication technique utilizing laser ablation to embed conductive elastomer nanocomposite within an insulating bulk elastomer. Nanocomposite consisting of poly(dimethylsiloxane) and a network of carbon nanotubes functions as a piezoresistive sensor material. Microstructures are embedded with the assist of laser ablation which utilizes a focused laser beam to ablate through a thin polymer film following a path programmed via software. This approach eliminates hardware such as photo-mask or stamp, which offers distinct advantages in reducing fabrication time and cost in prototyping of sensor devices. Various patterns of polymer film and embedded nanocomposite are demonstrated with spatial resolution down to 34 μm. To characterize patterning quality, different fabrication conditions are tested and uniformity (width, thickness) data are measured with optical profiling. Sensor prototypes are demonstrated based on the piezoresistive response of nanocomposite under tensile strain. Strain sensors could detect large-range (>45%) tensile strain with sensing a factor of about 4, showing promising feasibility for various sensing applications.     

High temperature dynamic viscosity sensor for engine oil applications

This paper presents a new high temperature dynamic viscosity sensor for in situ condition monitoring of engine lubricants. The sensor is used to measure the variation in the quality factor of a vibrating piezoelectric cantilever beam due to viscous damping. The sensor was used to measure the dynamic viscosity of various single and multi-grade engines oils up to 180 cP from 25 °C to 60 °C. The sensor is capable of detecting degradation and dilution of engine oil for both new and used samples of 5W-30 and 10W-40 and diluted SAE 30 engine oils. All of the viscosity measurements presented are within 0.13-9.8% of the results obtained using the standard Walther equation at various temperatures. An equation relating dynamic viscosity of an oil sample to the quality factor of the beam is presented. The quality factor measurement circuit presented in this research can be implemented in automotive applications for in situ condition monitoring of lubricant viscosity.     

Mapping the distribution of coral reefs and associated sublittoral habitats in Pacific Panama: a comparison of optical satellite sensors and classification methodologies

This research compared the ability of Landsat ETM+, Quickbird and three image classification methods for discriminating amongst coral reefs and associated habitats in Pacific Panama. Landsat ETM+ and Quickbird were able to discriminate coarse and intermediate habitat classes, but this was sensitive to classification method. Quickbird was significantly more accurate than Landsat (14% to 17%). Contextual editing was found to improve the user's accuracy of important habitats. The integration of object‐oriented classification with non‐spectral information in eCognition produced the most accurate results. This method allowed sufficiently accurate maps to be produced from Landsat, which was not possible using the maximum likelihood classifier. Object‐oriented classification was up to 24% more accurate than the maximum likelihood classifier for Landsat and up to 17% more accurate for Quickbird. The research indicates that classification methodology should be an important consideration in coral reef remote sensing. An object‐oriented approach to image classification shows potential for improving coral reef resource inventory.     

基于卫星遥感图像的变化检测算法

在石油勘探、开发炼制及运储过程中,由于意外事故或操作失误,造成原油或油品从作业现场储器里外泄,溢流向地面、水面、海滩或海面,同时由于油质的不同,形成薄厚等一片膜这现象称为溢油.大范围的海上溢油往往会对数个国家的生态、社会以及经济带来严重影响.本文基于卫星遥感数据,将变化检测引入海上溢油的问题中,研究实现对比了多个变化检测算法,最终实现了一个变化检测的溢油检测系统.实验表明,变化检测能有效地减少因地理位置、光照条件因素的影响,泛化能力显著地强于单幅图的分类方法,文章提供的系统能有效地将油区与水面、轻油区域与重油区域分割.     

Estimation of soil clay and calcium carbonate using laboratory, field and airborne hyperspectral measurements

This paper examines how reflectance spectrometry used in the laboratory to estimate clay and calcium carbonate (CaCO₃) soil contents can be applied to field and airborne measurements for soil property mapping. A continuum removal (CR) technique quantifying specific absorption features of clay (2206 nm) and CaCO₃ (2341 nm) was applied to laboratory, field and airborne HYMAP reflectance measurements collected in 2003 (33 sites) and 2005 (19 sites) over bare soil sites of a few meters within the La Peyne Valley area, southern France. Nine intermediate stages from the laboratory up to HYMAP sensor measurements were considered for separately evaluating the possible degradation of estimation performances when going across scales and sensors, e.g. radiometric calibration, spectral resolution, spatial variability, illumination conditions, and surface status including roughness, soil moisture and presence and nature of pebbles.Significant relationships were observed between clay and CaCO₃ contents and CR values computed respectively at 2206 nm and 2341 nm from reflectance measurements at the laboratory level with an ASD spectrophotometer up to the HYMAP spectro-imaging sensor. Performances of clay and CaCO₃ estimations decreased from the laboratory to airborne scales. The main factors inducing uncertainties in the estimates were radiometric and wavelength calibration uncertainties of the HYMAP sensor as well as possible residual atmospheric effects.     

实用的光纤电流传感器

提出了一种结构小巧（体积为3cm×4cm×1．5cm）、使用方便的光纤电流传感器．该系统的传感头是以Sagnac干涉仅原理为基础，利用法拉第光学材料作为传感元件，经过巧妙的结构设计构成．传感头不含有任何与们振有关的光学元件，并且待测的信号与光的偏振态和光强的起伏无关，使得该传感系统特别适用于电流遥测使用．初步实验结果和理论结果吻合．     

光纤传感器在油液污染度检测中的应用

在分析了油液污染产生的原因及其对机械设备的危害的基础上,利用油液中悬浮颗粒对光线的吸收,结合光纤传感系统的优点,设计了油液污染度光纤检测传感器。实验结果表明：该系统可以在一定程度上检测油液的污染度,在机械设备的实时在线检测中具有一定的应用价值。     

Searching for optimal sensitivity of single-mode D-type optical fiber sensor in the phase measurement

To improve the sensitivity of a single-mode D-type optical fiber sensor, we selected a D-type optical fiber sensor with 4 mm long and 4 μm core thickness made of a single-mode fiber, a Au-coating on the sensor with a thickness range of 15–32 nm, a light wavelength of 632.8 nm, and an incident angle of 86.5–89.5° for different refractive index (1.33–1.40) sensing. These simulations are based on the surface plasmon resonance (SPR) theory using the phase method which shows that the sensitivity is proportional to the refractive index, Au film thickness and lower incident angle on the sensing interface. The sensitivity is higher than 4000 (degree/RIU), and the resolution is better than 2.5 × 10⁻⁶(RIU) as the minimum phase variation is 0.01°. This device is used to detect the refractive index or gas or liquid concentration in real-time. The proposed sensor is small, simple, inexpensive, and provides an in vivo test.     

基于MTF的遥感影像复原算法研究

对引起遥感影像模糊的因素进行了分析,从光学系统、大气及传感器与地面的相对运动三方面出发,导出了遥感影像的调制传递函数,从而利用维纳滤波算法对遥感影像进行复原处理。考虑到遥感影像数据量大的问题,对图像采用分块处理的方法。实验结果表明该方法能有效的对退化的遥感影像进行复原。     

A physics based retrieval and quality assessment of bathymetry from suboptimal hyperspectral data

In order to retrieve bathymetry, substratum type and the concentrations of the optically active constituents of the water column, an integrated physics based mapping approach was applied to airborne hyperspectral data of Moreton Bay, Australia. The remotely sensed data were sub-optimal due to high and mid-level cloud covers. Critical to the correct interpretation of the resultant coastal bathymetry map was the development of a quality control procedure based on additional outputs of the integrated physics based mapping approach and the characteristics of the instrument. These two outputs were: an optical closure term which defines differences between the image and model based remote sensing signal; and an estimate of the relative contribution of the substratum signal to the remote sensing signal. This quality control procedure was able to identify those pixels with a reliable retrieval of depth and to detect thin and thick clouds and their shadows, which were subsequently masked out from further analysis. The derived coastal bathymetry in depths ranging 4-13 m for the mapped area was within ± 15% of boat-based multi-beam acoustic mapping survey of the same area. The agreement between the imaging spectrometry and the acoustic datasets varies as a function of the contribution of the bottom visibility to the remote sensing signal. As expected, there was greater agreement in shallower clear water (± 0.67 m) than quasi-optically deep water (± 1.35 m). The quantitative identification and screening of the optically deep waters and the quasi-optically deep waters led to improved precision in the depth retrieval. These results suggest that the physics based mapping approach adopted in this study performs well for retrieving water column depths in coastal waters in water depths ranging 4-13 m for the area and conditions studied, even with sub-optimal imagery.     

Fast response and recovery of nano-porous silicon based gas sensor

Fusion of the transduction mechanism in micro and macro nanopores of porous silicon (PS) was employed to fabricate an MEMS-based aliphatic alcohol impedance sensor. The presence of a nanopore network on silicon was confirmed by the SEM image. The morphology of the PS nanopores was roughly distributed in a uniform manner. The performance of the sensor was studied using Impedance spectroscopy at room temperature. Electrochemical impedance spectroscopy and an equivalent circuit analysis of the small amplitude (± 10 mV) AC impedance measurements (frequency range 0.1 Hz–1 kHz) at ambient temperature were carried out. The Sensing layer consists of nanopores (45.30–71.13 nm), micropores (0.95–5 µm), and comb type alumina electrodes with the micro PS layer having a thickness of about 0.2 µm and the macro PS layer having a thickness of about 4 µm. These results were used to assess the effect of the micro PS and macro PS of the particulate layer on the conductivity of the given aliphatic gases. The measured impedance was approximately 2.3e5 for the micro PS, and 3.22e5 macro PS for 8 ppm of gas injected into the gas chamber. The grain boundary resistance increases with an increase in the concentration of butane, benzene, and methane, which ranges from 2 to 16 ppm.

     

A micro shear stress sensor based on laterally aligned carbon nanotubes

This paper reports the development of a micro thermal shear stress sensor that utilizes multiwalled carbon nanotubes as the sensing element. The sensor was fabricated by laterally aligning randomly distributed nanotubes into a 360 μm long and 90 μm wide conductive trace between two triangular shaped micro electrodes through the use of a high frequency AC electric field. During operation, the aligned nanotubes are electrically heated to an elevated temperature and surface shear stress is measured indirectly by the amount of convective heat transfer from the heated nanotubes to the surrounding fluid flow.The nanotube alignment process was primarily controlled by three different phenomena: dielectrophoresis, joule heating, and Brownian motion. Numerical simulations, together with experimental verifications, indicated that a successful alignment could only be realized if: (1) the dielectrophoretic force was positive, (2) the electro-thermal force was also positive, and (3) the dielectrophoretic force was high enough to overcome Brownian motion. The aligned nanotube trace has a room-temperature resistance of 580 Ω, which corresponds to a conductivity of 2.7 × 10⁴ S/m. The absolute temperature coefficient of resistivity ranges from 0.01 to 0.04% °C⁻¹. This is about one order of magnitude smaller than the highly doped polysilicon sensing material used in the MEMS micro shear stress sensor. The shear stress sensitivity of the nanotube trace operated at a 3% overheat ratio is found to follow the theoretical sensor power ∝ (shear stress)^1/3 relationship, provided the shear stress level is higher than 0.34 mPa. This result confirms the feasibility of using aligned multi-walled carbon nanotubes as a thermal shear stress sensing material.     

Hybrid functional networks for oil reservoir PVT characterisation

Predicting pressure-volume-temperature (PVT) properties of black oil is one of the key processes required in a successful oil exploration. As crude oils from different regions have different properties, some researchers have used API gravity, which is used to classify crude oils, to develop different empirical correlations for different classes of black oils. However, this manual grouping may not necessarily result in correlations that appropriately capture the uncertainties in the black oils. This paper proposes intelligent clustering to group black oils before passing the clusters as inputs to the functional networks for prediction. This hybrid process gives better performance than the empirical correlations, standalone functional networks and neural network predictions.     

In‐pixel temperature sensor for high‐luminance active matrix micro‐light‐emitting diode display using low‐temperature polycrystalline silicon and oxide thin‐film‐transistors

We propose an in‐pixel temperature sensor using low‐temperature polycrystalline silicon and oxide (LTPO) thin‐film transistor (TFTs) for high‐luminance active matrix (AM) micro‐light‐emitting diode (LED) displays. By taking advantage of the different off‐current characteristics of p‐type LTPS TFTs and n‐type a‐IGZO TFTs under temperature change, we designed and fabricated a temperature sensor consists of only LTPO TFTs without additional sensing component or material. The fabricated sensor exhibits excellent temperature sensitivity of up to 71.8 mV/°C. In addition, a 64 × 64 temperature sensor array with 3T sensing pixel and integrated gate driver has also been fabricated, which demonstrates potential approach for maxing out the performance of high‐luminance AM micro‐LED display with real‐time in‐pixel temperature monitoring.     

基于嵌入式的布里渊分布式光纤传感远程网络控制系统

光纤传感器正向多点检测、远程控制、网络化方向发展,本文提出一种基于嵌入式的光纤传感远程网络控制系统设计方案,对传感原理、FPGA控制、数据的远程传输和采集参数控制进行了分析,并针对分布式光纤传感节点多、数据流量大的特点,应用多线程和线程槽技术到系统构建,完成了光纤传感网络的实际检测.     

Detection of ammonia in the ppt range based on a composite optical waveguide pH sensor

An optical waveguide (OWG) pH sensor with two thin guiding layers (composite OWG) was fabricated, and its application to sensing extremely low concentrations of ammonia was demonstrated. The highly sensitive element based on a titanium dioxide (TiO₂) film was deposited onto the surface of a potassium ion (K⁺) exchanged glass OWG by RF sputtering. The surface of the TiO₂ film was coated with a thin film of a pH indicator dye (bromothymol blue, BTB) by spin coating. With optimum thickness of BTB film at about 46 nm and of TiO₂ films at 18–20 nm, this system proved to be an extremely sensitive ammonia sensor. The experimental results of the optimum conditions on BTB and TiO₂ film thicknesses were close to theoretically calculated values. The sensor easily detected 1 parts per trillion (ppt) ammonia reversibly, and had a short response time. The present sensor is also characterized by low cost, simple structure and facile fabrication.