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51.
Tatiana G. Evreinova Grigori Evreinov Roope Raisamo Leena K. Vesterinen 《Universal Access in the Information Society》2008,7(1-2):93-102
Blind and visually impaired students need special educational and developmental tools to allow them to interact with graphic
entities on PDA and desktop platforms. In previous research, stylus movements regarding the hidden graph were sonified with
three directional-predictive sound (DPS) signals, taking into account an exploration behavior and the concept of the capture
radius. The results indicated that the scanpaths were by 24–40% shorter in length and task completion times decreased by 20–25%.
The goal of the study presented in this paper was to measure and compare the subjective performance recorded with directional-predictive
vibrations (DPV) regarding the subjective performance achieved when the hidden graphic images were explored with DPS. The
study also aimed to find out which kind of feedback cues would require less cognitive efforts in interpreting their meaning.
The prototype of vibro-tactile pen with embedded vibration motor was used to produce DPV instead of sounds. The performance
of eight blindfolded subjects was investigated in terms of the number of both feedbacks used and the time spent to complete
non-visual inspection of the hidden graphs. There was a statistically significant difference between the average number of
DPS and vibrations and task completion time taken by the players to discover the features of hidden graphs being explored
with different capture radius. The experimental findings confirmed the beneficial use of DPS signals in the task when cross-modal
coordination should benefit the user in the absence of visual information when compared with DPV patterns. 相似文献
52.
Anteo Smerieri Tatiana Berzina Victor Erokhin M.P. Fontana 《Materials science & engineering. C, Materials for biological applications》2008,28(1):18-22
A thin film polymeric junction was fabricated which yields a molecular electronic device functionally able to learn, i.e. to respond coherently to an external training signal. The fabricated structure is based upon electrochemical control of electronic current in a conducting polymer in contact with a solid electrolyte polymer. This functional behavior bears some resemblance to simple cases of biological learning processes. We report a comprehensive electronic characterization of the device function. Additional study was performed in order to estimate the possibility of the integration of such kinds of devices in statistical adaptive networks. 相似文献
53.
Yuri S. Lipatov Tatiana T. Alekseeva Lyubov A. Sorochinskaya Galina V. Dudarenko 《Polymer Bulletin》2008,59(6):739-747
Summary Peculiarities of formation kinetics of sequential semi-interpenetrating polymer networks based on crosslinked polyurethane
with different cross-linking density and linear polystyrene and polybutylmethacrylate have been studied. Polyurethane networks
were synthesized differing in molecular mass Mc of the chains between cross-links. Monomeric styrene and butyl methacrylate were introduced into these networks by swelling
them in monomers up to equilibrium. The kinetics of polymerization of monomers in swollen networks was investigated. The experimental
data show the dependence of the kinetic parameters of polymerization on Mc, this dependence being different for various monomers. Sharp discrepancy in molecular mass distribution of polymers formed
in various matrices has been observed. The differences in dependencies of reaction kinetics and molecular mass distribution
are supposed to be connected to various dependence of the chain growth and termination of various monomers on the density
of network, i.e. on the confinements imposed by the intranetwork space. 相似文献
54.
Tatiana V. Evreinova Grigori Evreinov Roope Raisamo 《Universal Access in the Information Society》2008,7(3):129-144
This paper presents the results of a comparative study of user input with a camera-joystick and a manual joystick used in
a target acquisition task when neither targets nor pointer could be perceived visually. The camera-joystick is an input technique
in which each on-screen item is accessible from the center with a predefined vector of head motion. Absolute pointing was
implemented with an acceleration factor of 1.7 and a moving average on 5 detected head positions. The underlying assumption
was that, in order to provide a robust input for blind users, the interaction technique has to be based on perceptually well-discriminated
human movements, which compose a basic framework of an accessible virtual workspace demanding minimum external auxiliary cues.
The target spots, having a diameter of 35 mm and a distance between the centers of adjacent spots of 60 mm, were arranged
in a rectangular grid of 5 rows by 5 columns. The targets were captured from a distance of 600 mm. The results have shown
that the camera input is a promising technique for non-visual human–computer interaction. The subjects demonstrated, more
than twice, better performance in the target acquisition task with the camera-joystick versus the manual joystick. All the
participants reported that the camera-joystick was a robust and preferable input technique when visual information was not
available. Blind interaction techniques could be significantly further improved allowing a user-dependent activation of the
navigational cues to better coordinate feedbacks with exploratory behavior. 相似文献
55.
Electron holography is a very powerful technique for mapping static electric and magnetic potentials down to atomic resolution. While electron holography is commonly considered synonymous with its off-axis variant in the high energy electron microscopy community, inline electron holography is widely applied in low-energy electron microscopy, where the realization of the off-axis setup is still an experimental challenge. This paper demonstrates that both inline and off-axis holography may be used to recover amplitude and phase shift of the very same object, in our example latex spheres of 90 and 200 nm in diameter, producing very similar results, provided the object does not charge under the electron beam. 相似文献
56.
Xavier Chaud Tatiana Prikhna Yaroslav Savchuk Anne Joulain Evert Haanappel Pavel Diko Laureline Porcar Mahmoud Soliman 《Materials Science and Engineering: B》2008,151(1):53
Oxygen high pressure (up to 16 MPa) has been introduced in the oxygen-annealing step necessary to make the YBa2Cu3Ox phase superconducting (change x from 6 to about 7). It enables a displacement in the equilibrium phase diagram towards higher temperatures, which means the possibility to achieve the same final oxygen content as the one at low temperature, but with the benefit of higher diffusion rates. Initial development made on thin bars (1.5–3 mm thick) has confirmed the interest of using a high pressure of oxygen. TEM observations have shown an increase of twin density associated with higher Jc. This is in agreement with other works claiming the possibility of higher Jc by twin engineering, and more precisely by twin refinement while annealing at high temperature. We report the successful application of this process without any adjustment to so-called thin-wall single-domain samples. These samples are obtained by growing a crystal on a pellet already shaped with an array of holes. The advantage is that, as far as diffusion processes are concerned, the typical length is not anymore the diameter of the sample, but the thickness of the walls between holes. The trapped field of 16 mm diameter Y123 thin-wall single-domain samples was doubled (0.6 T vs. 0.3 T at 77 K) in a rather short annealing time (about 3 days). Microstructures as well as magneto-optical observations of plain and thin-wall samples evidenced a reduction of cracks in the thin-wall samples. Improved performances were confirmed by further characterizations performed from 77 down to 20 K using the pulse-field facilities of the LNCMP at Toulouse. 相似文献
57.
Larisa I. Nasibulina Tatiana S. Koltsova Tuomo Joentakanen Albert G. Nasibulin Oleg V. Tolochko Jari E.M. Malm Maarit J. Karppinen Esko I. Kauppinen 《Carbon》2010,48(15):4559-4562
A novel approach to synthesize carbon nanofibers (CNFs) directly on the surface of metal μm-sized particles to evenly disperse the carbon nanomaterials in a composite material was proposed. As a metal matrix, 5–10 μm copper particles were utilized. As a carbon source, C2H2, CH4 and CO were examined. The best conditions were found to be in C2H2 (30 cm3/min) and H2 (260 cm3/min) atmosphere at the temperature of 750 °C. The composites based on copper and CNFs prepared by vacuum hot pressing showed the increase in hardness from 35 to 60 kg/mm2 almost retaining pure copper electrical properties. 相似文献
58.
Tatiana A. Kolesnikova Dmitry A. Gorin Paulo Fernandes Stefanie Kessel Gennady B. Khomutov Andreas Fery Dmitry G. Shchukin Helmuth Möhwald 《Advanced functional materials》2010,20(7):1189-1195
A water suspension of nanocomposite microcapsules with embedded ZnO nanoparticles in the capsule shell is reported. The microcapsule morphology is characterized by confocal microscopy, TEM, SEM, and AFM before and after ultrasound treatment. A remarkably high capsule sensitivity to ultrasound is evidenced, and it is observed to grow with increasing number of ZnO nanoparticle layers in the nanocomposite shell. This effect is correlated with the mechanical properties of microcapsules measured with AFM. 相似文献
59.
Diana Salikhova Tatiana Bukharova Elvira Cherkashova Daria Namestnikova Georgy Leonov Maria Nikitina Ilya Gubskiy Gevorg Akopyan Andrey Elchaninov Konstantin Midiber Natalia Bulatenco Victoria Mokrousova Andrey Makarov Konstantin Yarygin Vladimir Chekhonin Liudmila Mikhaleva Timur Fatkhudinov Dmitry Goldshtein 《International journal of molecular sciences》2021,22(9)
Transplantation of various types of stem cells as a possible therapy for stroke has been tested for years, and the results are promising. Recent investigations have shown that the administration of the conditioned media obtained after stem cell cultivation can also be effective in the therapy of the central nervous system pathology (hypothesis of their paracrine action). The aim of this study was to evaluate the therapeutic effects of the conditioned medium of hiPSC-derived glial and neuronal progenitor cells in the rat middle cerebral artery occlusion model of the ischemic stroke. Secretory activity of the cultured neuronal and glial progenitor cells was evaluated by proteomic and immunosorbent-based approaches. Therapeutic effects were assessed by overall survival, neurologic deficit and infarct volume dynamics, as well as by the end-point values of the apoptosis- and inflammation-related gene expression levels, the extent of microglia/macrophage infiltration and the numbers of formed blood vessels in the affected area of the brain. As a result, 31% of the protein species discovered in glial progenitor cells-conditioned medium and 45% in neuronal progenitor cells-conditioned medium were cell type specific. The glial progenitor cell-conditioned media showed a higher content of neurotrophins (BDNF, GDNF, CNTF and NGF). We showed that intra-arterial administration of glial progenitor cells-conditioned medium promoted a faster decrease in neurological deficit compared to the control group, reduced microglia/macrophage infiltration, reduced expression of pro-apoptotic gene Bax and pro-inflammatory cytokine gene Tnf, increased expression of anti-inflammatory cytokine genes (Il4, Il10, Il13) and promoted the formation of blood vessels within the damaged area. None of these effects were exerted by the neuronal progenitor cell-conditioned media. The results indicate pronounced cytoprotective, anti-inflammatory and angiogenic properties of soluble factors secreted by glial progenitor cells. 相似文献
60.
Igor Kosacki Vladimir Petrovsky Harlan U. Anderson Philippe Colomban 《Journal of the American Ceramic Society》2002,85(11):2646-2650
The results of Raman-scattering studies of nanocrystalline CeO2 and ZrO2 :16% Y (YSZ) thin films are presented. The relationship between the lattice disorder and the form of the Raman spectra is discussed and correlated with the microstructure. It is shown that the Raman line shape results from phonon confinement and spatial correlation effects and yields information about the material nonstoichiometry level. 相似文献