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Step Height (step + height)
Selected AbstractsExperimental study of mode-coupling strength of AT-cut quartz resonators with high mesa step heightELECTRONICS & COMMUNICATIONS IN JAPAN, Issue 1 2009Shigeyoshi Goka Abstract In this paper, the bi-mesa resonators, which can be fabricated with very high mesa steps, were fabricated, and their frequency,temperature (f,T) characteristics were measured as an index of the mode-coupling strength. Since the mode-coupling affects the first-order temperature coefficient of the TS-1 mode, the f,t curve of the pure TS-1 mode rotates clockwise depending on the mode-coupling strength. The experimental results showed that the tendency of the first-order coefficients of the measured f,T data were in good agreement with the calculated mode-coupling strength in the mesa height range of 0 to 50%. These results indicate the validity of the calculated mode-coupling strength between TS-1 and TF modes. It is also shown that choosing lower mesa height is desirable because the face-shear modes caused by the X,Z, boundary tend to couple with the TS-1 mode when the mesa step is very high. © 2009 Wiley Periodicals, Inc. Electron Comm Jpn, 92(1): 34,38, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecj.10227 [source] Critical flux determination by flux-steppingAICHE JOURNAL, Issue 7 2010Søren Prip Beier Abstract In membrane filtration related scientific literature, often step-by-step determined critical fluxes are reported. Using a dynamic microfiltration device, it is shown that critical fluxes determined from two different flux-stepping methods are dependent upon operational parameters such as step length, step height, and flux start level. Filtrating 8 kg/m3 yeast cell suspensions by a vibrating 0.45 × 10,6 m pore size microfiltration hollow fiber module, critical fluxes from 5.6 × 10,6 to 1.2 × 10,5 m/s have been measured using various step lengths from 300 to 1200 seconds. Thus, such values are more or less useless in itself as critical flux predictors, and constant flux verification experiments have to be conducted to check if the determined critical fluxes can predict sustainable flux regimes. However, it is shown that using the step-by-step predicted critical fluxes as start guesses, in our case, in constant flux verification experiments for 5 and 1/2 hours, a sustainable flux was identifiable. © 2009 American Institute of Chemical Engineers AIChE J, 2010 [source] Photoinduced Luminescence Blinking and Bleaching in Individual Single-Walled Carbon NanotubesCHEMPHYSCHEM, Issue 10 2008Carsten Georgi Abstract The temporal evolution of photoluminescence in individual single-walled carbon nanotubes (SWNT) under strong laser irradiation is studied and pronounced blinking and bleaching is observed, caused by photoinduced oxidation that subsequently quenches mobile excitons. The nanotubes are isolated with sodium cholate and spun onto either a glass or mica surface. Their bleaching behavior is investigated for variable laser intensities in air and argon atmosphere. The decay rate for luminescence bleaching generally increases with higher laser intensity, however saturating on mica substrates, which is attributed to limited availability of oxygen in the vicinity of the nanotubes. Step-like events in the luminescence time traces corresponding to single oxidation events are analyzed regarding relative step height and suggest an exciton diffusion range of about 105 nm. [source] A study of sulfamerazine single crystals using atomic force microscopy, transmission light microscopy, and Raman spectroscopyJOURNAL OF PHARMACEUTICAL SCIENCES, Issue 9 2005Xiaoping Cao Abstract Sulfamerazine (SMZ) Form I and II single crystals were prepared from aqueous dispersions of SMZ bulk samples and studied using several microscopic and spectroscopic techniques. Transmission light microscopy and Raman spectroscopy were used to observe and identify single crystals. The results indicated that Form I single crystals tended to be rectangular laths while Form II ones tended to be hexagonal laths. Surface morphology of individual single crystals was further investigated by atomic force microscopy (AFM). AFM images revealed a smooth top surface, a uniform height, and sharp edges for both forms of single crystals. Both height and phase images showed crystalline terraces with different step heights for the top surface of Form I. Surface properties of single crystals were evaluated using AFM force measurements. Experimental results indicated that the top surface of Form I single crystals was more hydrophilic than that of Form II. Theoretical calculations predicted a dominant crystal face of (020) for the Form I single crystals and (002) for the Form II ones. The correlations between calculation predictions and experimental results were discussed. © 2005 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 94:1881,1892, 2005 [source] Assembly, structure, and performance of an ultra-thin film organic field-effect transistor (OFET) based on substituted oligothiophenesPHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 3 2008K. Haubner Abstract We report on the improved assembly and characterization of a small molecule organic field-effect transistor (OFET). Novel ,,,-dicyano substituted ,,,,-dibutylquaterthiophene molecules (DCNDBQT) were synthesized and characterized by UV,Vis spectroscopy, differential scanning calorimetry, thermal gravimetric analysis and cyclic voltammetry. The ultra-thin organic film formation on TiO2 templates was effectively promoted through the specifically designed bifunctional self assembly molecules (SAM) 5-cyano-2-(butyl-4-phosphonic acid)-3-butylthiophene (CNBTPA). Excellent structural properties were found for up to 9 DCNDBQT molecule thick films prepared through UHV vacuum sublimation as investigated with UHV non-contact atomic force microscopy (nc-AFM) and X-ray diffraction. Both X-ray and nc-AFM data indicate that the DCNDBQT molecules form a well-ordered terraced structure exhibiting step heights of 1.5 nm to 2.0 nm layers. Hence, the DCNDBQTmolecules are linked to the functional SAM interface layer by H-bond interactions (see structure model) standing quasi perpendicular to the TiO2 template, and thus providing optimal orbital overlap neigh-bouring thiophene rings. The vacuum sublimated DCNDBQT molecules form a closed packed and dense molecular layer that was used to construct and operate a nanoscopic OFET-structure. The resulting field mobilities of 10,5 cm2 V,1 s,1 reflect a high current density in our ultrathin but highly ordered structure. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] | ||||||||||