1,281 research outputs found
Ionic Liquid as Green Solvent for Ring-Opening Graft Polymerizaion of ε-Caprolactone onto Hemicelluloses
Synchronization of fractional order chaotic systems
The chaotic dynamics of fractional order systems begin to attract much
attentions in recent years. In this brief report, we study the master-slave
synchronization of fractional order chaotic systems. It is shown that
fractional order chaotic systems can also be synchronized.Comment: 3 pages, 5 figure
The Neural Network Pushdown Automaton: Model, Stack and Learning Simulations
In order for neural networks to learn complex languages or grammars, they
must have sufficient computational power or resources to recognize or generate
such languages. Though many approaches have been discussed, one obvious
approach to enhancing the processing power of a recurrent neural network is to
couple it with an external stack memory - in effect creating a neural network
pushdown automata (NNPDA). This paper discusses in detail this NNPDA - its
construction, how it can be trained and how useful symbolic information can be
extracted from the trained network.
In order to couple the external stack to the neural network, an optimization
method is developed which uses an error function that connects the learning of
the state automaton of the neural network to the learning of the operation of
the external stack. To minimize the error function using gradient descent
learning, an analog stack is designed such that the action and storage of
information in the stack are continuous. One interpretation of a continuous
stack is the probabilistic storage of and action on data. After training on
sample strings of an unknown source grammar, a quantization procedure extracts
from the analog stack and neural network a discrete pushdown automata (PDA).
Simulations show that in learning deterministic context-free grammars - the
balanced parenthesis language, 1n0n, and the deterministic Palindrome - the
extracted PDA is correct in the sense that it can correctly recognize unseen
strings of arbitrary length. In addition, the extracted PDAs can be shown to
be identical or equivalent to the PDAs of the source grammars which were used
to generate the training strings.
(Also cross-referenced as UMIACS-TR-93-77.
Sintering Kinetics of Plasma-Sprayed Zirconia TBCs
A model of the sintering exhibited by EB-PVD TBCs, based on principles of free energy minimization, was recently published by Hutchinson et al. In the current paper, this approach is applied to sintering of plasma-sprayed TBCs and comparisons are made with experimental results. Predictions of through-thickness shrinkage and changing pore surface area are compared with experimental data obtained by dilatometry and BET analysis respectively. The sensitivity of the predictions to initial pore architecture and material properties are assessed. The model can be used to predict the evolution of contact area between overlying splats. This is in turn related to the through-thickness thermal conductivity, using a previously-developed analytical model
The effects of the bacterial interaction with visible-light responsive titania photocatalyst on the bactericidal performance
Bactericidal activity of traditional titanium dioxide (TiO2) photocatalyst is effective only upon irradiation by ultraviolet light, which restricts the potential applications of TiO2 for use in our living environments. Recently carbon-containing TiO2 was found to be photoactive at visible-light illumination that affords the potential to overcome this problem; although, the bactericidal activity of these photocatalysts is relatively lower than conventional disinfectants. Evidenced from scanning electron microscopy and confocal Raman spectral mapping analysis, we found the interaction with bacteria was significantly enhanced in these anatase/rutile mixed-phase carbon-containing TiO2. Bacteria-killing experiments indicate that a significantly higher proportion of all tested pathogens including Staphylococcus aureus, Shigella flexneri and Acinetobacter baumannii, were eliminated by the new nanoparticle with higher bacterial interaction property. These findings suggest the created materials with high bacterial interaction ability might be a useful strategy to improve the antimicrobial activity of visible-light-activated TiO2
Phonon thermal conductivity in doped : Relevant scattering mechanisms
Results of in-plane and out-of-plane thermal conductivity measurements on
() single crystals are
presented. The most characteristic features of the temperature dependence are a
pronounced phonon peak at low temperatures and a steplike anomaly at ,
i.e., at the transition to the low temperature tetragonal phase (LTT-phase),
which gradually decrease with increasing Sr-content. Comparison of these
findings with the thermal conductivity of and clearly reveals that in the most effective
mechanism for phonon scattering is impurity-scattering (dopants), as well as
scattering by soft phonons that are associated with the lattice instability in
the low temperature orthorhombic phase (LTO-phase). There is no evidence that
stripe correlations play a major role in suppressing the phonon peak in the
thermal conductivity of .Comment: 7 pages, 4 figure
Search for the Rare Decays J/Psi --> Ds- e+ nu_e, J/Psi --> D- e+ nu_e, and J/Psi --> D0bar e+ e-
We report on a search for the decays J/Psi --> Ds- e+ nu_e + c.c., J/Psi -->
D- e+ nu_e + c.c., and J/Psi --> D0bar e+ e- + c.c. in a sample of 5.8 * 10^7
J/Psi events collected with the BESII detector at the BEPC. No excess of signal
above background is observed, and 90% confidence level upper limits on the
branching fractions are set: B(J/Psi --> Ds- e+ nu_e + c.c.)<4.8*10^-5, B(J/Psi
--> D- e+ nu_e + c.c.) D0bar e+ e- + c.c.)<1.1*10^-5Comment: 10 pages, 4 figure
Study of J/psi decays to Lambda Lambdabar and Sigma0 Sigma0bar
The branching ratios and Angular distributions for J/psi decays to Lambda
Lambdabar and Sigma0 Sigma0bar are measured using BESII 58 million J/psi.Comment: 11 pages, 5 figure
Measurements of J/psi Decays into 2(pi+pi-)eta and 3(pi+pi-)eta
Based on a sample of 5.8X 10^7 J/psi events taken with the BESII detector,
the branching fractions of J/psi--> 2(pi+pi-)eta and J/psi-->3(pi+pi-)eta are
measured for the first time to be (2.26+-0.08+-0.27)X10^{-3} and
(7.24+-0.96+-1.11)X10^{-4}, respectively.Comment: 11 pages, 6 figure
Measurements of Cabibbo Suppressed Hadronic Decay Fractions of Charmed D0 and D+ Mesons
Using data collected with the BESII detector at storage ring
Beijing Electron Positron Collider, the measurements of relative branching
fractions for seven Cabibbo suppressed hadronic weak decays ,
, and , , and are presented.Comment: 11 pages, 5 figure
- …