Narrow Results

Discrimination between hazardous materials in the environment and ambient constituents is a fundamental problem in environmental sensing. The ubiquity of naturally occurring bacteria, plant pollen, fungi, and other airborne materials makes the task of sensing for biological warfare (BW) agents particularly challenging. The spectroscopic properties of the chemical warfare (CW) agents in the long wavelength infrared (LWIR) region are important physical properties that have been successfully exploited for environmental sensing. However, in the case of BW agents, the LWIR region affords less distinction between hazardous and ambient materials. Recent studies of the THz spectroscopic properties of biological agent simulants, particularly bacterial spores, have yielded interesting and potentially useful spectral signatures of these materials. It is anticipated that with the advent of new THz sources and detectors, a novel environmental sensor could be designed that exploits the peculiar spectral properties of the biological materials. We will present data on the molecular spectroscopy of several CW agents and simulants as well as some THz spectroscopy of the BW agent simulants that we have studied to date, and discuss the prospectus with regard to detection probabilities through the application of sensor system modeling.

In this paper we explore the design of microwave-based structures that can enhance the interaction of electromagnetic fields with cold-atom ensembles, leading to novel sensing modalities based on the quantum-mechanical behavior of these systems. In particular, we discuss electromagnetically-induced transparency in a single uncondensed cold-atom cloud, and a two-cloud version of a SQUID, where the clouds are BEC's and take the place of the weakly coupled superconductors. These systems are both promising candidates for use in the high-precision detection of chemical contaminants.

This paper presents comparative analysis of different wavelength ranges for the spectroscopic detection of acetone vapor. We collected and analyzed original absorption line spectra arising from electronic transitions in the ultraviolet, near-infrared vibrational overtones, mid-infrared fundamentals, THz torsional modes, and mm-wave rotational transitions. Peak absorption cross sections of prominent spectral features are determined. The relative merit of each spectral range for sensing is considered, taking into account the absorption strength, available technology, and possible interferences.

On nine unanesthetized male rabbits, the frequency spectra of hypothalamic electrogram (EEG) were studied during low intensity (10 mW/cm2) millimeter wave (55–75 GHz) exposure to various acupuncture points (zone): auricular, cranial and corporal. The chances of occurrence of significant (p < 0.05) changes in the EEG spectra during irradiation versus. sham experiments were equal to 31, 21 and 5%, respectively. Exposure to auricular zone reduced the EEG power in narrow bands with central frequencies of 5.3, 15.9 Hz and increased ones of 2.6, 3.2, 6.9, 7.9, 11.5 and 25.6 Hz. The main effect of exposure to cranial zone was similar — changes at 15.9 and 25.6 Hz only. The data obtained demonstrate that the responsiveness of the central nervous system to low intensity millimeter wave radiation may depend on the location of the exposed acupuncture zone.

The objective of this paper is to discuss the opportunities of an advanced RFCMOS for millimeter-wave applications based on an assessment of figures of merits including relevant device information. This paper introduces the RF specifications for 45 nm CMOS node and present the evolution of RF-FOMs with gate downscaling over the previous generations. Especially, since 45 nm CMOS is the technology to be available in production, a particular focus on its RF performance for power and bandwidth is given.

The main characteristics of millimeter-wave (MM-wave) image detector were simulated by means of accurate numerical modeling of thermophysical processes in a metamaterial MM-to-IR converter. The converter represents a multilayer structure consisting of an ultra thin resonant metamaterial absorber and a perfect emissive layer. The absorber consists of a dielectric self-supporting film that is metallized from both sides. A micro-pattern is fabricated from one side. Resonant absorption of the MM waves induces the converter heating that yields enhancement of IR emission from the emissive layer. IR emission is detected by IR camera. In this contribution an accurate numerical model for simulation of the thermal processes in the converter structure was created by using COMSOL Multiphysics software. The simulation results are in a good agreement with experimental results that validates the model. The simulation shows that the real-time operation is provided for the converter thickness less than 3 μm and time response can be improved by decreasing of the converter thickness. The energy conversion efficiency of MM waves into IR radiation is over 80%. The converter temperature increase is a linear function of a MM-wave radiation power within three orders of the dynamic range. The blooming effect and ways of its reducing are also discussed. The model allows us to choose the ways of converter structure optimization and improvement of image detector parameters.

Discrimination between hazardous materials in the environment and ambient constituents is a fundamental problem in environmental sensing. The ubiquity of naturally occurring bacteria, plant pollen, fungi, and other airborne materials makes the task of sensing for biological warfare (BW) agents particularly challenging. The spectroscopic properties of the chemical warfare (CW) agents in the long wavelength infrared (LWIR) region are important physical properties that have been successfully exploited for environmental sensing. However, in the case of BW agents, the LWIR region affords less distinction between hazardous and ambient materials. Recent studies of the THz spectroscopic properties of biological agent simulants, particularly bacterial spores, have yielded interesting and potentially useful spectral signatures of these materials. It is anticipated that with the advent of new THz sources and detectors, a novel environmental sensor could be designed that exploits the peculiar spectral properties of the biological materials. We will present data on the molecular spectroscopy of several CW agents and simulants as well as some THz spectroscopy of the BW agent simulants that we have studied to date, and discuss the prospectus with regard to detection probabilities through the application of sensor system modeling.

In this paper we explore the design of microwave-based structures that can enhance the interaction of electromagnetic fields with cold-atom ensembles, leading to novel sensing modalities based on the quantum-mechanical behavior of these systems In particular, we discuss electromagnetically-induced transparency in a single uncondensed cold-atom cloud, and a two-cloud version of a SQUID, where the clouds are BEC's and take the place of the weakly coupled superconductors. These systems are both promising candidates for use in the high-precision detection of chemical contaminants.

This paper presents comparative analysis of different wavelength ranges for the spectroscopic detection of acetone vapor. We collected and analyzed original absorption line spectra arising from electronic transitions in the ultraviolet, near-infrared vibrational overtones, mid-infrared fundamentals, THz torsional modes, and mm-wave rotational transitions. Peak absorption cross sections of prominent spectral features are determined. The relative merit of each spectral range for sensing is considered, taking into account the absorption strength, available technology, and possible interferences.