22 research outputs found
X-ray and neutron diffraction studies of the hydration of SeO4= and CrO4= anions by isomorphic substition.
No full textThe structure in aqueous solutions of the hydrated selenate and chromated ions SeO42- and CrO42- have been derived from X-ray and neutron diffraction measurements using CrO42- as an isomorphous substitute for SeO42-. The Se(Cr)-O bond lengths are 1.63 +/- 0.02 angstrom and do not differ from those found in crystal structure.
A well defined hydration shell of about 12 water molecules surrounds the XO42- ions at a Se(Cr)-H2O distance of 3.96 angstrom. The diffraction results indicate a geometrical orientation of the water molecule around the tetrahedral anions very similar to that one found in the case of simple anions such as Cl-, with Se(Cr)-D distances of 3.25 and 4.4 angstrom and with a Se(Cr)-O distance of 3.96 angstro
Apple II direct memory access interface to acquire neutron scattering time of flight spectra
No full text
Single particle dynamics in fluid and solid hydrogen sulphide: an inelastic neutron scattering study
No full textConfocal, wide band spectral reflection microscope, and relevant spectral imaging method
No full textThis invention concerns a wideband spectral reflectance confocal microscope comprising a laser source (LS), a beam expander (BE) inserted immediately after the laser source (LS), a beam splitter (BS) in an adequately transparent material through the whole spectral interval emitted by the laser source (LS), a system (OB1) to focus the laser beam on the sample (S) presenting a working distance greater than 5mm and a numerical aperture greater than 0.25, a collection system (M, OB2, PH) and an analysis system (AS) of the laser beam reflected by the sample and transmitted by the beam splitter (BS), said analysis system (AS) comprising a chromatic dispersion subsystem capable of forming the spectrum to be analysed, the microscope being characterized in that: said laser source (LS) is a source that emits simultaneously at several wavelengths in the visible and infrared regions; said focusing system (OB1 ) is free of chromatic aberration; said beam splitter (BS) is positioned at 45° in respect of the laser beam direction; said collection system (M, OB2, PH) is free of chromatic aberration; so that at each analysed point of the sample (S) corresponds unambiguously a frequency response spectrum collected by the collection system (M, OB2, PH). The invention concerns as well a spectral imaging method of a sample (S) by means of a wideband spectral reflectance confocal microscope, besides the utilisation of the microscope of this invention for the same imaging
Label-free and non-invasive discrimination of HaCaT and melanoma cells in a co-culture model by hyperspectral confocal reflectance microscopy
No full textA novel hyperspectral confocal microscopy method to separate different cell populations in a co-culture model is presented here. The described methodological and instrumental approach allows discrimination of different cell types using a non-invasive, label free method with good accuracy with a single cell resolution. In particular, melanoma cells are discriminated from HaCaT cells by hyperspectral confocal imaging, principal component analysis and optical frequencies signing, as confirmed by fluorescence labelling cross check. The identification seems to be quite robust to be insensitive to the cellular shape within the studied samples, enabling to separate cells according to their cytotype down to a single cell sensitivity. Set of hyperspectral images of melanoma-keratinocytes co-culture model (left), score plot of principal component analysis and spectral analysis of principal components coefficients (center), label-free spectral identification of cell populations (right)
A new technique for the study of phase transitions by means of energy dispersive X-ray diffraction. Application to polymeric samples
No full textA new application of energy dispersive x-ray diffraction to the kinetics of phase transitions is reported. The aim of this work is to provide a new investigation tool to follow the evolution of polymeric systems from the initial to the final phase. The theoretical treatment is developed both for constant density transitions and for the variable density ones. The experimental route is illustrated by an example
Temperature dependence of PEO phase transition rate by energy dispersive X-ray diffraction
No full textA new energy dispersive x-ray diffraction method was used to observe isothermal phase transitions of a polyethylene oxide sample contained in a variable temperature cell. A series of scattering measurements were performed to follow the time evolution of the system at each temperature. The collected spectra were suitably processed and the transition coordinate x was obtained as a function of time. A detailed treatment of the errors was accomplished to evaluate the reliability of the method. The experimental points (dx/dt)(max) - T were plotted both for the amorphous-crystalline (below the melting temperature T-m) and for the crystalline-amorphous (over T-m) transitions. They reproduce the usual behavior for T T-m which is partially justified
PRISMA - a spectrometer for the measurement of coherent excitations on a pulsed spallation neutron source
No full textThe measurement of nuclear and magnetic excitation spectra from single crystal samples remains central to condensed matter physics. The requirements in terms of the range and resolution of the scattering vector Q and energy transfer h ω are reviewed and typical experiments with a well defined cross-section are chosen. The performance and limitations of existing instruments are reviewed. A design for a new spectrometer, PRISMA, to be installed on the UK spallation neutron source, ISIS, is presented. Its performance for chosen experiments is given in terms of the Q and h ω range covered in a single scan, the resolution and the count rate
