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121.
Yuancong Zhao 《Applied Surface Science》2010,257(5):1596-1601
Crystalline TiO2 films were prepared by unbalanced magnetron sputtering and the structure was confirmed by XRD. An organic layer of 11-hydroxyundecylphosphonic acid (HUPA) was prepared on the TiO2 films by self-assembling, and the HUPA on TiO2 films was confirmed by FTIR analysis. Simultaneously, hydroxyl groups were introduced in the phosphonic acid molecules to provide a functionality for further chemical modification. 2-Methacryloyloxyethyl phosphorylcholine (MPC), a biomimetic monomer, was chemically grafted on the HUPA surfaces at room temperature by surface-initiated atom-transfer radical polymerization. The surface characters of TiO2 films modified by poly-MPC were confirmed by FTIR, XPS and SEM analysis. Platelet adhesion experiment revealed that poly-MPC modified surface was effective to inhibit platelet adhesion in vitro. 相似文献
122.
O. Idigoras 《Journal of magnetism and magnetic materials》2010,322(20):L57
We have studied the magnetization reversal of uniaxial Co(1 0 1 0) films as a function of the applied field orientation by means of magneto-optical Kerr effect microscopy. Hereby, we find that while stable intermediate domain states exist for most field directions, their occurrence is suppressed for field orientations along the easy axis of magnetization. To facilitate this study, we have developed a data extraction methodology that allows for the quantitative analysis and compact display of entire magnetization distribution field-sequences in a single picture. It furthermore allows for the automated data analysis to unambiguously distinguish magnetization rotation processes from field-induced domain formation. 相似文献
123.
The BixSb1-x film is an important phase change material. The ultrafast dynamics of BixSb1-x film is studied by the femtosecond pump-probe technique with an 80 fs pulsed laser. Experimental results show that the reflectivity change increases with the fluence of the pump laser. The fast increase of the reflectivity occurs between 100 and 800 fs. Subsequently, the slower recovery of the reflectivity on a time scale of 1.24-18.3 ps is detected. We also found that the reflectivity change can be greatly affected by the ratio between Bi and Sb composition in BixSb1-x materials with x = 0.2 and 0.88. These experimental results should be helpful for developing new devices with ultrafast dynamics of BixSb1-x film and ultrafast optical switching. 相似文献
124.
L. Ward 《Optics & Laser Technology》1997,29(2):103-108
Abelès' equations (in terms of 1; 2 and optical film thickness x) for all the eight optical functions (Rs; Rp; Ts; Tp; Fs; Fp; Xs and Xp) have been expressed in the form of equations representing standard geometrical three-dimensional figures. Xs and Xp are represented by plane surfaces whilst the remainder are skew cones. Translated into the n; k notation; Xs and Xp generate hyperboloids whilst the remainder produce paraboloids whose cross-sections are parts of figures of eight. 相似文献
125.
Ultrafast transverse thermoelectric voltage response has been observed in c‐axis inclined epitaxial La0.5Sr0.5CoO3thin films. Voltage signals with the rise time of 7 ns have been detected under the irradiation of pulse laser with duration of 28 ns. A concept, named response rate ratio, has been proposed to evaluate the intrinsic response rate, and this ratio in La0.5Sr0.5CoO3is smaller than that in other reported materials. The low resistivity is thought to be responsible for the ultrafast response, as low resistivity induces small optical penetration depth, and response time has a monotonous increasing relationship with this depth.
126.
The main mechanisms of leakage currents in thin lead zirconate titanate (PZT) ferroelectric films prepared by the sol–gel method are discussed. Four specific regions are determined in I–V dependencies. At very weak fields (10–20 kV/cm), the current falls with the voltage increase as a result of depolarization. In the low fields region (about 70–100 kV/cm), the leakage current decreases with the decrease of voltage ramp speed and its components are the ohmic and displacement currents. In the high fields region (≥130 kV/cm), the leakage current increases with the decrease of step voltage ramp in contrast to the previous case. Possible conductivity mechanisms are the Poole– Frenkel emission and hopping conduction. In the transition region between above-mentioned ones (from 80–90 to ~130 kV/cm), an abrupt unstable increase of current is observed caused by breakdown of reverse bias Schottky barrier. Depolarization currents are studied for sol–gel PZT films prepared at different preparation conditions. 相似文献
127.
Studies on CdS nanoparticles dispersed in silica matrix prepared by sol-gel technique 总被引:2,自引:0,他引:2
B. Bhattacharjee S.K. Bera D. Ganguli S. Chaudhuri A.K. Pal 《The European Physical Journal B - Condensed Matter and Complex Systems》2003,31(1):3-9
SiO2/CdS-nanoparticle composite films (SiO2:CdS=85:15, 80:20, 75:25 and 70:30) were prepared by the sol-gel route. The films were characterized by studying microstructural
(XRD and TEM) and optical (transmittance and photoluminescence) properties. Band gaps of these films annealed at different
temperatures (373-473 K) for different times (10-120 min) indicated that the signature of nanocrystallinity is retained throughout
the range of our experimental conditions. A thermal diffusion process controlled growth in the crystallite size with increasing
annealing time and temperature. The average radii of the nanoparticles varied as the cube root of the annealing time but showed
exponential dependence on the inverse of annealing temperature. Photoluminescence (PL) studies of the composite films indicated
excitonic transitions. Theoretical analysis of the line shapes of the PL peaks recorded at 300 K and 80 K could be accounted
for by the combined effects of size distribution and phonon broadening. It was observed that the deformation potential (E
d) effectively controlled the line shapes of the PL measurements.
Received 24 May 2002 Published online 27 January 2003
RID="a"
ID="a"e-mail: msakp@mahendra.iacs.res.in 相似文献
128.
B. Fraboni P. Cosseddu Y.Q. Wang R.K. Schulze A. Cavallini M. Nastasi A. Bonfiglio 《Physica B: Condensed Matter》2012,407(15):3047-3051
We report on the effects of low energy ion implantation (N and Ne) in the reduction and control of the degradation of pentacene organic thin film transistors (OTFTs) due to the exposure to atmosphere (i.e. oxygen and water). We have observed that a controlled damage depth distribution preserves the functionality of the devices, even if ion implantation induces significant molecular structure modifications, in particular a combination of dehydrogenation and carbonification effects. No relevant changes in the pentacene thin film thickness have been observed. The two major transport parameters that characterize OTFT performance are the carrier mobility and the threshold voltage. We have monitored the effectiveness of this process in stabilizing the device by monitoring the carrier mobility and the threshold voltage over a long time (over 2000 h). Finally, we have assessed by depth resolved X-ray Photoemission Spectroscopy analyses that, by selectively implanting with ions that can react with the hydrocarbon matrix (e.g. N+), it is possible to locally modify the charge distribution within the organic layer. 相似文献
129.
Transport properties of La0.8Ba0.2MnO3 thin films deposited by the sol–gel method were investigated. It has been found that resistivity plateaus occurred in the ρ–T curves after application of a dc bias current over a critical value. A current of 200 μA could induce a huge resistance variation ∼1200% in these La0.8Ba0.2MnO3 films near room temperature, demonstrating a colossal electroresistance effect. Such strange transport behavior suggests the formation of conductive filaments and that the multi-phase coexistence is sensitive to external stimuli. This phenomenon may find applications in sensing and logic devices. 相似文献
130.
《Mathematical Methods in the Applied Sciences》2018,41(1):159-191
A semilinear parabolic problem is considered in a thin 3‐D star‐shaped junction that consists of several thin curvilinear cylinders that are joined through a domain (node) of diameter The purpose is to study the asymptotic behavior of the solution uε as ε→0, ie, when the star‐shaped junction is transformed in a graph. In addition, the passage to the limit is accompanied by special intensity factors and in nonlinear perturbed Robin boundary conditions. We establish qualitatively different cases in the asymptotic behavior of the solution depending on the value of the parameters {αi}and {βi}. Using the multiscale analysis, the asymptotic approximation for the solution is constructed and justified as the parameter ε→0. Namely, in each case, we derive the limit problem (ε=0)on the graph with the corresponding Kirchhoff transmission conditions (untypical in some cases) at the vertex, define other terms of the asymptotic approximation and prove appropriate asymptotic estimates that justify these coupling conditions at the vertex, and show the impact of the local geometric heterogeneity of the node and physical processes in the node on some properties of the solution. 相似文献