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Rotational spectra of the methylamine and acetaldehyde molecules were recorded in the frequency range between 80 and 120 GHz with sub-Doppler spectral resolution. Such resolution was achieved by means of Lamb-dip observation. The main aim of this study was to search for the torsionally mediated anomalous high-J hyperfine splittings in acetaldehyde and methylamine molecules, similar to that ones recently...
In this paper, a compact multi-use volatile molecular sensor with high sensitivity is demonstrated. The sensor design is based on a planar metamaterial-inspired modified split ring resonator with open gap (OmSRR) forming an effective inductive-capacitive (LC) resonant tank having high quality (Q) factor with operating frequency near 7.4 GHz. Between two ring structure a capacitive gap is designed...
A CMOS wideband dielectric spectroscopy system is proposed for chemical and biological material characterization. The complex permittivity detection is performed using a configurable harmonic-rejecting receiver capable of indirectly measuring the complex admittance of sensing capacitor exposed to the material-under-test (MUT) and subject to RF signal excitation with a frequency range of 0.62–10GHz...
We report on the first demonstration of a quartz enhanced photo-acoustic (QEPAS) sensor in the Terahertz (THz) range. The sensor is based on a QCL emitting at 3.93 THz and a customized quartz tuning fork. For methanol detection we reached a normalized noise-equivalent absorption of 2×10−10 cm−1W/Hz½ comparable with the best result of mid-IR QEPAS.
The 2D measurements on a light harvesting complex by Fleming and coworkers showed long lived oscillations [1] suggesting the existance of quantum-coherent effects in large macromolecules. In order to gain a deeper insight into these coherent phenomena, the intramolecular energy dissipation in restricted size molecules has to be investigated. Here we present a combined pump-probe and 2D-UV investigation...
Various studies of specific absorption rates (SARs) using liquid phantoms imitating human body tissues have been widely carried out in electromagnetic compatibility (EMC) research fields. In order to establish accurate SARs for measurement, a faithful mockup of human body tissue is needed. Therefore, knowledge of the accurate measurement of sample materials with high permittivity and high loss is...
A Lamb wave sensor to measure the concentration of methanol solution in direct methanol fuel cell (DMFC) systems was designed, fabricated and evaluated. The sensor piezoelectrically generates the lowest antisymmetric mode (A0-mode) Lamb wave on a suspended thin AlN/SiO2/Si composite membrane, and confines a standing wave with edge reflectors. The fabricated sensor showed an almost constant sensitivity...
Controlling the methanol concentration is a key factor in improving the efficiency of the direct methanol fuel cell. In this study, the immersed-type Love mode sensor based on SiO2/ST-cut Y-propagation quartz was fabricated for monitoring the methanol concentration. A temperature controlled measurement system consisting of a spectrum analyzer and an oscillator circuit was employed to characterize...
We report the application of a quartz crystal microbalance (QCM) in an inductively coupled measurement. Inductive coupling makes it possible to locate the sensing element in a hostile environment and to perform measurements without direct wired connections. We demonstrate inductively coupled sensing of methanol in nitrogen using a poly(ethyl methacrylate) adsorbing layer. The gas-related signal is...
Quantum cascade lasers operating at about 2.5 terahertz have been implemented in a spectrometer for high resolution molecular spectroscopy. Linewidth, frequency tunability and frequency stability of the lasers were investigated by mixing their radiation with radiation from a 2.5 terahertz gas laser. Two first laser characteristics were found to be sufficient for Doppler-limited spectroscopy. For a...
The TE010 mode cylindrical cavity was used for accurate complex permittivity measurements of lossy liquids at frequencies 7.4 GHz and 7.8 GHz. The complex permittivity was evaluated from measured resonance frequencies and Q-factors of the cavity with and without liquid under test employing rigorous electromagnetic analysis of the resonant structure in the complex frequency domain. Influence of the...
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