Noise expresses exponential growth under regime switching

Consider a given system under regime switching whose solution grows at most polynomially, and suppose that the system is subject to environmental noise in some regimes. Can the regime switching and the environmental noise work together to make the system change signicantly? The answer is yes. In this paper, we will show that the regime switching and the environmental noise will make the original system whose solution grows at most polynomially become a new system whose solution will grow exponentially. In other words, we reveal that the regime switching and the environmental noise will exppress the exponential growth

Preparation and ferroelectric properties of (124)-oriented SrBi4Ti4O15 ferroelectric thin film on (110)-oriented LaNiO3 electrode

A (124)-oriented SrBi4Ti4O15 (SBTi) ferroelectric thin film with high volume fraction of {\alpha}SBTi(124)=97% was obtained using a metal organic decomposition process on SiO2/Si substrate coated by (110)-oriented LaNiO3 (LNO) thin film. The remanent polarization and coercive field for (124)-oriented SBTi film are 12.1 {\mu}C/cm2 and 74 kV/cm, respectively. No evident fatigue of (124)-oriented SBTi thin film can be observed after 1{\times}10e9 switching cycles. Besides, the (124)-oriented SBTi film can be uniformly polarized over large areas using a piezoelectric-mode atomic force microscope. Considering that the annealing temperature was 650{\deg}C and the thickness of each deposited layer was merely 30 nm, a long-range epitaxial relationship between SBTi(124) and LNO(110) facets was proposed. The epitaxial relationship was demonstrated based on the crystal structures of SBTi and LNO.Comment: 11 pages, 4 figures, published in Journal of Materials Science: Materials in Electronics (JMSE), 19 (2008), 1031-103

Laboratory NMR Study to Quantify the Water Saturation of Partially Saturated Porous Rocks

The low-field nuclear magnetic resonance (NMR) technique is widely used as a noninvasive method to characterize the water content of subsurface porous media, such as aquifers and hydrocarbon reservoirs, but the quantitative correlation between the water saturation and the NMR relaxation signal has not been fully addressed. We conducted a laboratory study to measure the NMR signals of sandstone samples with different water saturations and to develop an empirical model for estimating the water saturation. The partially saturatinthe irreducible water saturationg states were derived by a high-speed centrifuge. The result shows that the water saturation is proportional to the geometric mean of the transverse relaxation time and can be fitted through a power function. Moreover, it has been found that the fitting parameters vary with the porosity and exhibit similar behaviors with the parameters of the classical Archie equation. The water saturation as well as its mobility state can be estimated with the NMR signals and porosity data. The proposed method has the potential to be applied to detect and quantify the water content in vadose zones, phreatic aquifers, permafrost regions, and gas hydrate reservoirs

Lower Bounds for Error-Correcting Codes with Local Recovery

Error-correcting codes (ECCs) are ubiquitous in computer science. A common property of ECCs is local recovery, which demands that given a corrupted codeword, a single lost code symbol can be recovered by reading only a small part of the codeword. An intriguing problem is to find the most "efficient" ECCs (e.g., codes with short length, codes over a small alphabet) with certain types of local recovery. Both constructions and lower bounds have been proven in the literature. However, the problem is still largely open. In this thesis, we prove three lower bound results on different types of ECCs with local recovery: Firstly, we propose an approximate version of locally decodable codes (LDCs) and prove lower bounds that are similar to the known ones for traditional LDCs. The concerned approximate LDCs are over real numbers and they support recoveries by querying constant number of codeword symbols. The 2-query case (the bulk of our work) is partially related to the lower bound of constant query LDCs, which is a major open problem. Secondly, we generalize the Sylvester-Gallai (SG) theorem to a subspace version. Generally speaking, the setting of the SG theorem is equivalent to 2-query locally correctable codes (LCCs), and our generalization corresponds to the block version of 2-query LCCs. Thirdly, we consider a realistic storage model that is a unification of several families of codes studied in the literature. We prove negative results for codes that attain the maximal recovering capability under this model. Our lower bound rules out the possibility of constructions of efficient codes for most parameter settings. We will also explore some results in the construction direction in the appendix

EFFECTS OF La DOPING ON FERROELECTRIC PROPERTIES OF CaBi4Ti4O15 THIN FILMS

La modified CBTi (CLBTi) thin films were prepared on Pt/Ti/SiO2/Si(100) substrates by a sol–gel technique. X-ray diffraction analysis showed that single phase of CLBTi thin films were obtained. Their crystallization and hysteresis behavior were strongly dependent on the La contents. An increase of 2Pr as well as a decrease of 2Ec with the increase of La concentration were observed. The leakage properties of CBTi thin films were found to be improved by the La doping. The results were discussed with respect to the effects of La3+ substitution at perovskite A-site.Ferroelectric thin film, bismuth layered perovskite, CaBi4Ti4O15, oxygen vacancy

Structural Damage Detection based on an Improved Edge-Detection Technique

To Localize Small Damage from Mode Shapes, the Polynomial Annihilation Edge Detection Method Has Been Proposed and Demonstrated its Effectiveness on Different Types of Structural Components [7]. However, Much Computational Effort Involved in This Approach Lowers the Damage Detection Speed. to Alleviate This Difficulty, in This Paper, We Improve the Approach by First using the Divided Difference Approach to Identify the Region(S) in Which Jump Discontinuities Are Located, and Then Only Applying the Polynomial Annihilation Method to Points in the Identified Region. in This Way, the Computational Burden of This Approach is Significantly Relieved, While the Accuracy is Still Maintained. the Improved Approach Has Been Validated by Numerical Simulations on a Cable-Stayed Bridge Model. This Approach Only Requires Post-Damage Mode Shapes. Copyright © 2013 by Alstom Technologie AG

STRUCTURE CONTROL AND FERROELECTRIC PROPERTIES OF SrBi4Ti4O15 THIN FILMS ON Si SUBSTRATES COATED BY (100)- AND (110)-ORIENTED LaNiO3 ELECTRODES

SrBi4Ti4O15 (SBTi) thin films were prepared on (100)- and (110)-oriented LaNiO3(LNO) electrodes by a metalorgranic decomposition (MOD) technique at an annealing temperature of 650°C. c-axis-oriented SBTi thin film with volume fraction of 0.89 can be formed on a (100)-oriented LNO film due to the epitaxial relationship between c-axis-oriented SBTi and LNO(100). In contrast, SBTi film deposited on LNO(110) shows random orientations with strong (119) and (200) peaks. The remanent polarization (Pr) and coercive field (Ec) of the random oriented SBTi film were 18.1 μC/cm2 and 70 kV/cm, respectively. This suggests that (110)-oriented LNO electrode is a better choice for obtaining SBTi films with higher volume fraction of a(b)-axis-orientated grains.SrBi4Ti4O15 thin film, LaNiO3 thin film, metalorganic decomposition, epitaxial growth