360 research outputs found
Dose influence on the PMMA e-resist for the development of high-aspect ratio and reproducible sub-micrometric structures by electron beam lithography
In this work, a statistical process control method is presented showing the accuracy and the reliability obtained with of PMMA E-resist AR-P 672, using an Elphy Quantum Electron Beam Lithography module integrated on a FE-SEM Zeiss Auriga instrument. Reproducible nanostructures with an high aspect ratio between e-resist thickness and width of written geometric structure are shown. Detailed investigation of geometry features are investigated with dimension in the range of 200nm to 1-m. The adopted method will show how tuning the Area Dose factor and the PMMA thickness it was possible to determine the correct and reproducible parameters that allows to obtain well defined electron-beam features with a 4:1 aspect ratio. Such high aspect ratio opens the possibility to realize an electron-beam lithography lift-off process by using a standard e-beam resist. © 2016 Author(s)
Not invasive analyses on a tin-bronze dagger from Jericho. A case study
Tin-bronze makes its appearance in Southern Levant during the Early Bronze IV, the post-urban phase of the last centuries of the 3rdmillennium BC, when arsenical copper was still the most widespread copper alloy. Only from the following Middle Bronze Age tin-bronze will be the utmost spread alloy. The adoption of tin as alloying metal purports new technological skills, and a changed trade supply system, through new routes, thanks to itinerant coppersmiths. The examination of dagger TS.14.143 found in an EB IV (2300-2000 BC) tomb at Jericho by mean of trace elements and Energy Dispersive X-ray Diffraction analyses, provided info about its metal composition and technology. The detection of tin, testified only by a few specimens at the site so far, allows some reflections about the beginning of diffusion tin-bronze, and the presence of a small-scale melting activity in the post-urban phase in the key-site of Jericho
Role of ionic liquids in protein refolding: native/fibrillar versus treated lysozyme
Several ionic liquids (ILs) are known to revert aggregation processes and
improve the in vitro refolding of denatured proteins. In this paper the
capacity of a particular class of ammonium based ILs to act as refolding
enhancers was tested using lysozyme as a model protein. Raman spectra of ILs
treated fibrillar lysozyme as well as lysozyme in its native and fibrillar
conformations were collected and carefully analyzed to characterize the
refolding extent under the effect of the IL interaction. Results obtained
confirm and largely extend the earlier knowledge on this class of protic ILs
and indicate Ethyl Ammonium Nitrate (EAN) as the most promising additive for
protein refolding. The experiment provides also the demonstration of the high
potentiality of Raman spectroscopy as a comprehensive diagnostic tool in this
field.Comment: 11 pages, 6 figures, 3 table
Silver-doped Calcium Phosphate bone cements with antibacterial properties
Calcium phosphate bone cements (CPCs) with antibacterial properties are demanded for clinical applications. In this study, we demonstrated the use of a relatively simple processing route based on preparation of silver-doped CPCs (CPCs-Ag) through the preparation of solid dispersed active powder phase. Real-time monitoring of structural transformations and kinetics of several CPCs-Ag formulations (Ag = 0 wt %, 0.6 wt % and 1.0 wt %) was performed by the Energy Dispersive X-ray Diffraction technique. The partial conversion of β-tricalcium phosphate (TCP) phase into the dicalcium phosphate dihydrate (DCPD) took place in all the investigated cement systems. In the pristine cement powders, Ag in its metallic form was found, whereas for CPC-Ag 0.6 wt % and CPC-Ag 1.0 wt % cements, CaAg(PO₃)₃ was detected and Ag (met.) was no longer present. The CPC-Ag 0 wt % cement exhibited a compressive strength of 6.5 ± 1.0 MPa, whereas for the doped cements (CPC-Ag 0.6 wt % and CPC-Ag 1.0 wt %) the reduced values of the compressive strength 4.0 ± 1.0 and 1.5 ± 1.0 MPa, respectively, were detected. Silver-ion release from CPC-Ag 0.6 wt % and CPC-Ag 1.0 wt % cements, measured by the Atomic Emission Spectroscopy, corresponds to the average values of 25 µg/L and 43 µg/L, respectively, rising a plateau after 15 days. The results of the antibacterial test proved the inhibitory effect towards pathogenic Escherichia coli for both CPC-Ag 0.6 wt % and CPC-Ag 1.0 wt % cements, better performances being observed for the cement with a higher Ag-content
Ia Scuola Sperimentale di diffrazione a raggi-X a dispersione energetica (EDXD) ed angolare (ADXD)”,
Obiettivo : Scuola sperimentale di diffrazione di raggi X per laureati, dottorandi e ricercator
Visiting Professore
Progetto. X ray diffraction solutions of ZnSO4 and CdSO
Visiting Professor
Progetto: Diffraction data from some solutions of CdCl
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