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Author Lieberzeit, Peter A.; Dickert, Franz L.
Title Chemosensors in environmental monitoring: challenges in ruggedness and selectivity Type Journal Article
Year 2009 Publication Analytical and Bioanalytical Chemistry Abbreviated Journal Anal Bioanal Chem
Volume 393 Issue 2 Pages 467-472
Keywords environmental monitoring, in situ sensing, artificial recognition materials, real-life application, molecular imprinting, QCM
Abstract Environmental analysis is a potential key application for chemical sensors owing to their inherent ability to detect analytes on-line and in real time in distributed systems. Operating a chemosensor in a natural environment poses substantial challenges in terms of ruggedness, long-term stability and calibration. This article highlights current trends of achieving both the necessary selectivity and ruggedness: one way is deploying sensor arrays consisting of robust broadband sensors and extracting information via chemometrics. If using only a single sensor is desired, molecularly imprinted polymers offer a straightforward way for designing artificial recognition materials. Molecularly imprinted polymers can be utilized in real-life environments, such as water and air, aiming at detecting analytes ranging from small molecules to entire cells.
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Series Volume Series Issue Edition
ISSN 1618-2642 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number Serial 564
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Author Parrott, Edward P. J.; Zeitler, J. Axel; Fris<cc><152>c<cc><152>ic<cc><81>, Tomislav; Pepper, Michael; Jones, William; Day, Graeme M.; Gladden, Lynn F.
Title Testing the sensitivity of terahertz spectroscopy to changes in molecular and supramolecular structure: a study of structurally similar cocrystals Type Journal Article
Year 2009 Publication Crystal Growth & Design Abbreviated Journal Crystal Growth & Design
Volume 9 Issue 3 Pages 1452-1460
Keywords supramolecular recognition, infrared, terahertz, IR, THz, TDS
Abstract Terahertz time-domain-spectroscopy (THz-TDS) has emerged as a versatile spectroscopic technique, and an alternative to powder X-ray diffraction in the characterization of molecular crystals. We tested the ability of terahertz spectroscopy to distinguish between chiral and racemic hydrogen-bonded cocrystals that are similar in molecular and supramolecular structure. Terahertz spectroscopy readily distinguished between the isostructural cocrystals of theophylline with chiral and racemic forms of malic acid which are almost identical in molecular structure and supramolecular architecture. Similarly, the cocrystals of theophylline with chiral and racemic forms of tartaric acid, which are similar at the molecular level but dissimilar in crystal packing, were distinguished unequivocally. The investigation of the same cocrystals using X-ray powder diffraction and Raman spectroscopy suggested that THz-TDS is comparable in sensitivity to diffraction methods and more sensitive than Raman spectroscopy to changes in cocrystal architecture. The differences in spectra acquired by THz-TDS could be further enhanced by cooling the samples to 109 K.
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Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1528-7483 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number Serial 567
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Author Ryabchun, S. A.; Tretyakov, I. V.; Finkel, M. I.; Maslennikov, S. N.; Kaurova, N. S.; Seleznev, V. A.; Voronov, B. M.; Gol'tsman, G. N.
Title NbN phonon-cooled hot-electron bolometer mixer with additional diffusion cooling Type Conference Article
Year 2009 Publication Proc. 20th Int. Symp. Space Terahertz Technol. Abbreviated Journal Proc. 20th ISSTT
Volume Issue Pages 151-154
Keywords HEB, mixer, bandwidth, noise temperatue, in-situ contacts, in situ contacts
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Corporate Author Thesis (down)
Publisher Place of Publication Charlottesville, USA Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
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ISSN ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number Serial 590
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Author Ryabchun, S. A.; Tretyakov, I. V.; Pentin, I. V.; Kaurova, N. S.; Seleznev, V. A.; Voronov, B. M.; Finkel, M. I.; Maslennikov, S. N.; Gol'tsman, G. N.
Title Low-noise wide-band hot-electron bolometer mixer based on an NbN film Type Journal Article
Year 2009 Publication Radiophys. Quant. Electron. Abbreviated Journal
Volume 52 Issue 8 Pages 576-582
Keywords HEB mixer, in-situ contacts, noise temperature, conversion gain bandwidth, diffusion cooling channel
Abstract We develop and study a hot-electron bolometer mixer made of a two-layer NbN–Au film in situ deposited on a silicon substrate. The double-sideband noise temperature of the mixer is 750 K at a frequency of 2.5 THz. The conversion efficiency measurements show that at the superconducting transition temperature, the intermediate-frequency bandwidth amounts to about 6.5 GHz for a mixer 0.112 μm long. These record-breaking characteristics are attributed to the improved contacts between a sensitive element and a helical antenna and are reached due to using the in situ deposition of NbN and Au layers at certain stages of the process.
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Notes Approved no
Call Number Serial 599
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Author Рябчун, С. А.; Третьяков, И. В.; Пентин, И. В; Каурова, Н. С.; Селезнев, В. А; Воронов, Б. М.; Финкель, М. И.; Масленников, С. Н.; Гольцман, Г. Н.
Title Малошумящий широкополосный терагерцовый смеситель на эффекте электронного разогрева в плёнке NbN Type Journal Article
Year 2009 Publication Известия высших учебных заведений. Радиофизика Abbreviated Journal
Volume 52 Issue 8 Pages 641-648
Keywords HEB mixer, in-situ contacts, noise temperature, conversion gain bandwidth, diffusion cooling channel
Abstract Разработан и исследован смеситель на горячих электронах, изготовленный из двуслойной плёнки NbN-Au, осаждённой на кремневую подложку in situ. Двухполосная шумовая температура устройства составила 750 К на частоте 2.5 ТГц. Измерения эффективности преобразования для смесителя длиной 0.112 мкм вблизи температуры сверхпроводящего перехода показали полосу промежуточных частот около 6.5 ГГц. Эти результаты являются рекордными и были получены за счёт улучшения контактов между чувствительным элементом и спиральной антенной при замене технологического маршрута с нанесением слоёв NbN и Au в отдельных процессах на технологический процесс, в котором данные слои наносятся in situ без нарушения вакуума.
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Area Expedition Conference
Notes Approved no
Call Number Serial 600
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