共查询到20条相似文献,搜索用时 15 毫秒
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Recent advances of sensor technologies have been powered by high-speed and low-cost electronic circuits, novel signal processing methods, and advanced manufacturing technologies. The synergetic interaction of new developments in these fields provides promising technical solutions increasing the quality, reliability, and economic efficiency of technical products. With selected examples, we will give an overview about the significant developments of methods, structures, manufacturing technologies, and signal processing characterizing today's sensors and sensor systems. Predominantly observed development trends in the future are discussed. 相似文献
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A new ultra-light structure based on the application of open-cell metal foams has been designed and investigated to determine its ability for attenuation of γ-rays and thermal neutrons. Open-cell metal foam, a unique class of material, has been employed in the structure and is studied in this work where radiation attenuation abilities of foams and foams filled with water and borated water have been compared with bulk Aluminum. The γ-ray attenuation measurements were performed using γ-ray at 0.662, 1.173 and 1.332 MeV photon energies and thermal neutron attenuation measurements were conducted using a polyenergetic thermal neutron beam. The results show that the metallic foam by itself attenuates less γ-ray as compared to bulk material, while the mass attenuation coefficients of foams filled with water is higher than that of bulk metals. The thermal neutron experiment, on the other hand, has shown a dramatic attenuation improvement in foams filled with water and particularly with borated water as compared to bulk metal and foam. 相似文献
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《Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment》2002,476(1-2):149-154
The Transportable Neutron Spectrometer (TNS) has been used by the Ministry of Defence for over 15 years to characterise neutron fields in workplace environments and provide local correction factors for both area and personal dosimeters. In light of advances in neutron spectrometry, a programme to evaluate and improve TNS has been initiated. This paper describes TNS, presents its operation in known radioisotope fields and in a reactor environment. Deficiencies in the operation of the instrument are highlighted, together with proposals for updating the response functions and spectrum unfolding methodologies. 相似文献
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《技术计量学》2013,55(2):252-261
The detection of high-energy γ-ray sources is vitally important to national security for numerous reasons, particularly nuclear materials smuggling interdiction and threat detection. This article presents two methods of detecting and locating a concealed nuclear γ-ray source by analyzing detector data of emissions that have been modulated with a coded mask. The advantages of each method, derived from a simulation study and experimental data, are discussed. Energetic γ-rays readily penetrate moderate amounts of shielding material and can be detected at distances of many meters. Coded masks are spatial configurations of shielding material (e.g., small squares formed from plates of lead or tungsten) placed in front of a detector array to modulate the radiation distribution. A coded mask system provides improved detection through an increased signal-to-noise ratio. In a search scenario it is impossible to obtain a comparison background run without the presence of a potential concealed source. The developed analysis methods simultaneously estimate background and source emissions and thus provide the capability to detect and locate a concealed high-energy radiological source in near real time. An accurate source location estimate is critically important to expedite the investigation of a high-probability γ-ray source. The experimental examples presented use a proof-of-concept coded mask system of a 4 × 4 array of NaI detectors directed at a γ-ray source in a field-of-view roughly 4 m wide × 3 m high (approximately the size of the side panel of a small freight truck). Test results demonstrate that the correct location of a radiologic source could be determined in as little as 100 seconds when the source was 6 m from the detector. 相似文献
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《IEEE sensors journal》2006,6(5):1134-1143
This paper is devoted to the development of high temperature,$gamma$ , and neutron radiation resistant ultrasonic sensors that must operate continuously in a liquid Pb/Bi alloy up to a temperature of 450$^circhboxC$ . The main problems are acoustic coupling of a piezoelectric element to a protector and wetting of the sensor by a heavy liquid metal. The piezoelement was attached to the sensor body by a gold to gold diffusion bonding process, monitored ultrasonically. Long-lasting wetting of the active surface of the sensors was achieved by coating the front face with a protective diamond-like carbon (DLC) layer. Due to the high radiation, only a limited number of materials could be used in the sensor design. The best performance was obtained using bismuth titanate piezoelectric elements, which showed no noticeable changes of pulse responses and transfer coefficients during irradiation and high-temperature tests. The housing of the sensors is made of stainless steel AISI 316 and is laser welded, and a high-temperature$varnothing$ 1-mm 15-m-long mineral cable is used. The ultrasonic velocity in the liquid Pb/Bi in the temperature range 160$^circhboxC$ –460$^circhboxC$ was measured using developed sensors, and the signal losses at various distances up to 0.8 m were evaluated. 相似文献
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《IEEE sensors journal》2009,9(1):29-35
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Baranidharan Raman Theofilos Kotseroglou Lori Clark Michal Lebl Ricardo Gutierrez-Osuna 《IEEE sensors journal》2007,7(4):506-514
This paper presents a neuromorphic approach for sensor-based machine olfaction that combines a portable chemical detection system based on microbead array technology with a biologically inspired model of signal processing in the olfactory bulb. The sensor array contains hundreds of microbeads coated with solvatochromic dyes adsorbed in, or covalently attached on, the matrix of various microspheres. When exposed to odors, each bead sensor responds with corresponding intensity changes, spectral shifts, and time-dependent variations associated with the fluorescent sensors. The bead array responses are subsequently processed using a model of olfactory circuits that capture the following two functions: chemotopic convergence of receptor neurons and center on-off surround lateral interactions. The first circuit performs dimensionality reduction, transforming the high-dimensional microbead array response into an organized spatial pattern (i.e., an odor image). The second circuit enhances the contrast of these spatial patterns, improving the separability of odors. The model is validated on an experimental dataset containing the responses of a large array of microbead sensors to five different analytes. Our results indicate that the model is able to significantly improve the separability between odor patterns, compared to that available from the raw sensor response 相似文献
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J.P. Vidal G. Vidal-Valat C.M.E. Zeyen 《Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment》1985,228(2-3):569-575
Extinction effects are very often severe in ionic single crystals. Corrections for these effects depend mainly on theoretical models which describe primary extinction effects only poorly. In order to reduce the primary extinction, different thermal treatments were applied to MgF2 samples. γ-ray rocking curves were recorded to visualize the effects of these thermal treatments. The aptitude of a sample to give the best results in neutron and X-ray intensity measurements was decided on the basis of the shape of the γ-ray rocking curve profiles. The isotropic mosaic spread extinction parameter values obtained from γ-ray, X-ray and neutron techniques were of the same order of magnitude. 相似文献
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《IEEE sensors journal》2009,9(8):987-993
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We will consider the problem of detecting transient-like signals by means of a spatially distributed array of sensors embedded in an inhomogeneous, nonstationary noise field. If each element of the array has an independent, uncorrupted reference sensor to estimate the noise statistics, then conventional adaptive noise cancellation algorithms can be used to improve the detection process. However, because of practical real-world constraints, independent, uncorrupted reference sensors for the noise might not be available. Thus, the applicability of conventional adaptive noise cancellation techniques is in question. This paper will discuss the development of a knowledge-based signal-processing system that uses Artificial Intelligence (Al) methodologies to adaptively cancel inhomogeneous, nonstationary noise from a distributed array of passive sensors that is constrained to have no noise-reference sensors. 相似文献
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Lee WH 《Applied optics》1984,23(23):4280-4284
Charge coupled device (CCD) image sensors are currently used in many image processing applications such as facsimile and bar code reading. Because the photodetectors in the device have finite areas, the output signal from the CCD image sensor is only an approximation to the sampled value of the image. In this paper we discuss the reconstruction of bar codes from the imperfect CCD signal by digital signal processing techniques. Schemes for encoding digital data in the form of bar codes are also discussed. 相似文献
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Recent progress in biomedical sensing technologies has resulted in the development of several novel sensor products and new applications. Modern biomedical sensors developed with advanced microfabrication and signal processing techniques are becoming inexpensive, accurate, and reliable. A broad range of sensing mechanisms has significantly increased the number of possible target measurands that can be detected. The miniaturization of classical "bulky" measurement techniques has led to the realization of complex analytical systems, including such sensors as the BioChemLab-on-a-Chip. This rapid progress in miniature devices and instrumentation development will significantly impact the practice of medical care as well as future advances in the biomedical industry. Currently, electrochemical, optical, and acoustic wave sensing technologies have emerged as some of the most promising biomedical sensor technologies. In this paper, important features of these technologies, along with new developments and some of the applications, are presented. 相似文献
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Wide P. Winquist F. Bergsten P. Petriu E.M. 《IEEE transactions on instrumentation and measurement》1998,47(5):1072-1077
Presently, an increased interest is apparent for the development of integrated human-like smell and taste sensing capabilities, e.g. for chemical, paper pulp, food, and medicine applications. This paper will present an original sensor fusion method based on human expert opinions about smell and taste and measurement data from artificial nose and taste sensors. The “electronic nose” consists of an array of gas sensors with different selectivity patterns, signal handling, and a sensor signal pattern recognition and decision strategy. The “electronic tongue”, which was developed for the taste analysis of liquids is based on pulse voltammetry. Measurement data from the artificial smell and taste sensors are used to produce sensor-specific opinions about these two human-like sensing modalities. This is achieved by a team of artificial neural networks and conventional signal handling which approximates a Bayesian decision strategy for classifying the sensor information. Further, a fusion algorithm based on the maximum likelihood principle provides a combination of the smell and, respectively, taste opinions, into an overall integrated opinion similar to human beings. The proposed integrated smell- and taste-sensing method is then illustrated by an application of real world measurements in the food industry 相似文献
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Ronil J. Rath Syamak Farajikhah Farshad Oveissi Fariba Dehghani Sina Naficy 《Advanced Engineering Materials》2023,25(3):2200830
Gas detection and monitoring are essential due to their direct impact on human health, environment, and ecosystem. Chemiresistive sensors are one of the most used classes of sensors for monitoring and measurement of gases thanks to their ease of fabrication, customizability, mechanical flexibility, and fast response time. While chemiresistive sensors can offer good sensitivity and selectivity to a particular gas in a controlled environment with known interferences, they may not be able to differentiate between various gases having similar physiochemical properties under uncontrolled conditions. To address this shortcoming of chemiresistive gas sensors, sensor arrays have been the subject of recent studies. Gas sensor arrays are a group of individual gas sensors that are arranged to simultaneously detect and differentiate multiple cross-reactive gases. In this regard, various sensor array technologies have been developed to differentiate a given set of gases using multivariate algorithms. This review provides an insight into the different algorithms that are used to extract the data from the sensor arrays, highlighting the fabrication techniques used for developing the sensor array prototypes, and different applications in which these arrays are used. 相似文献
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Integrated arrays of Hall-type magnetic sensors are generally subject to significant crosstalk due to poor spatial selectivity of very closely spaced sensors. In this paper, we explore blind source separation as a signal processing technique to unmix a number of magnetic sources that impinge on the array. The processing consists of two stages: the first one estimates the source number and projects the observations on the signal subspace; the second stage is a source separation algorithm. Experimental results from a silicon array of Hall sensors, interfaced with a DSP, demonstrate real-time separation of two magnetic sources even under ill-conditioning of the mixing matrix. 相似文献
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Guan S 《Analytical chemistry》2003,75(17):4551-4557
Chemical vapors can be detected by a resonant mass sensor array with selective absorption coatings implementing a frequency encoding method. The sensor array consists of sensor elements with different frequencies for their identifications in the frequency response obtained with a pulse Fourier transform detection scheme. Zero-loading resonance frequencies are chosen so that frequency shift due to absorption is bounded within a predefined region so that there is no overlap of peaks and all peaks can be assigned to the correct elements at any operation conditions. Mechanical oscillations of all or selected numbers of the sensor elements are excited by application of an excitation signal. Free oscillation decay signals from all or selectively excited sensor elements are detected and digitized. The free oscillation decay signal is subjected to a spectral analysis routine converting into a frequency spectrum, in which frequency shifts due to absorption of chemical vapors can be obtained. The implementation of the frequency encoding method with pulse Fourier transform detection to resonant mass sensors allows simultaneous multisensor detection, fast data acquisition speed, high signal-to-noise ratio by coaddition of raw data, flexible excitation, reduced complexity of electronic hardware, application of advanced data/spectral analysis algorithms, and realization of many other advantages by the introduction of the pulse Fourier transform method. A practical chemical vapor sensing system is demonstrated experimentally by use of nine frequency-encoded and polymer-coated sensors. 相似文献
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Large-scale remotely interrogated arrays of fiber-optic interferometric sensors for underwater acoustic applications 总被引:8,自引:0,他引:8
The fiber-optic interferometric acoustic sensor array has established itself as a potential alternative to the conventional sonar array based on electroceramic transducers. In this paper, we discuss all the aspects of a large-scale fiber-optic interferometric sensor array. We review the basic operating principles of the fiber-optic interferometric sensor, signal processing, and multiplexing techniques, we present results from a noise model for a full size system, and we determine the benefit of incorporating a remotely-pumped optical amplifier in the array. As a practical example we describe the design and construction of a prototype array with 96 hydrophones incorporating a remotely pumped erbium-doped fiber amplifier, called the fiber-optic bottom mounted array, which is based on a dense wavelength division and time division multiplexed architecture. These arrays have applications in military sonar and seismic surveying. 相似文献