Study of the morphological change of amorphous ITO films after temperature–humidity treatment

Amorphous indium tin oxide (ITO) thin films have been deposited on silicon and Corning 7059 glass substrates at room temperature (RT) and at 75 °C by direct-current magnetron sputtering method. After exposure of the two kinds of samples to the temperature–humidity (T–H) test, we find that there are two different types of circular structures are formed. RT ITO films are composed of granules, and 75 °C ITO films are composed of several different parts which have different Sn and In concentrations. Metallic ion concentration corrosion cells are used to explain the phenomena.     

Decomposability of Polytopes

A known characterization of the decomposability of polytopes is reformulated in a way which may be more computationally convenient, and a more transparent proof is given. New sufficient conditions for indecomposability are then deduced, and illustrated with some examples.     

The splitting of separatrices,the branching of solutions and non-integrability in the problem of the motion of a spherical pendulum with an oscillating suspension point

The effectiveness of the results obtained previously in [Dovbysh SA. Transversal intersection of separatrices and non-existence of an analytical integral in multidimensional systems. In: Ambrosetti A, Dell Antonio GF, editors. Variational and Local Methods in the Study of Hamiltonian Systems. Singapore, etc: World Scientific; 1995. p. 156–65; Dovbysh SA. Transversal intersection of separatrices, the structure of a set of quasi-random motions and the non-existence of an analytic integral in multidimensional systems. Uspekhi Mat Nauk 1996; 51(4): 153–54; Dovbysh SA. Transversal intersection of separatrices and branching of solutions as obstructions to the existence of an analytic integral in many-dimensional systems. I. Basic result: Separatrices of hyperbolic periodic points. Collect Math 1999; 50(2): 119–97; Dovbysh SA. Branching of the solutions in the complex domain from the point of view of symbolic dynamics and the non-integrability of multidimensional systems. Dokl Ross Akad Nauk 1998; 361(3): 303–6] on the non-integrability of multidimensional systems is illustrated using the example of the problem of the motion of a spherical pendulum with a suspension point performing small periodic oscillations. With this aim, the splitting of the separatrices of the unstable equilibrium position and the branching of the solutions are investigated. It is shown that the separatrices are split for any law of motion of the suspension point, and a simple criterion of the presence of their transversal intersection is obtained. The validity of the non-integrability result, based on a combination of the conditions related to the splitting of multidimensional separatrices and to the branching of the solutions, is also pointed out.     

Adaptive synchronization of chaotic systems with less measurement and actuation

We investigate the synchronization problem between identical chaotic systems only when necessary measurement(output) and actuation(input) are needed to be implemented by the adaptive controllers. A sufficient condition is derived based on the Lyapunov stability theory and Schur complementary lemma. Moreover, the theoretic result is applied to the Rikitake system and the hyperchaotic Liu system to show its effectiveness and correctness. Numerical simulations are presented to verify the results.     

Noncommutative coordinate picture of the quantum phase space

We illustrate an isomorphic representation of the observable algebra for quantum mechanics in terms of the functions on the projective Hilbert space, and its Hilbert space analog, with a noncommutative product in terms of explicit coordinates and discuss the physical and dynamical picture. The isomorphism is then used as a base for the translation of the differential symplectic geometry of the infinite dimensional manifolds onto the observable algebra as a noncommutative geometry. Hence, we obtain the latter from the physical theory itself. We have essentially an extended formalism of the Schr̎odinger versus Heisenberg picture which we describe mathematically as like a coordinate map from the phase space, for which we have presented argument to be seen as the quantum model of the physical space, to the noncommutative geometry coordinated by the six position and momentum operators. The observable algebra is taken essentially as an algebra of formal functions on the latter operators. The work formulates the intuitive idea that the noncommutative geometry can be seen as an alternative, noncommutative coordinate, picture of familiar quantum phase space, at least so long as the symplectic geometry is concerned.     

Design and simulation of charge transport in single-electron transistor using TCAD numerical simulator

The ability to control the electron flow of a MOSFET is decreased due to the quantum mechanical effect when scaled down below 50 nm. Hence, A new field of device research is needed to complete this challenge. A device based on Tunneling phenomena is called a single-electron device. In this paper, the most fundamental single-electron device is a single-electron transistor (SET) designed using visual TCAD with a gate length and width of 2 nm. The channel is ultra-thin with a length of 2 nm and a width of 0.005 nm, and the channel thickness is 0.3 nm. Then a Si quantum dot of size 0.5 × 1.nm² is used between the island and the gate. Both the Devices are simulated using the Genius Simulator. And it is found that at room temperature, the device with Si dot is more efficient. The device with Si dot has less capacitance and higher charging efficiency than the device without the Quantum dot.     

Asymmetric coexisting bifurcations and multi-stability in an asymmetric memristive diode-bridge-based Jerk circuit

An asymmetric memristive diode-bridge (MDB) emulator is raised to imitate the asymmetric volt-ampere characteristic of a physical memristor. Then, an asymmetric MDB-based Jerk circuit is built and its state equation is derived, upon which the theoretical analysis, MATLAB-based numerical simulations, and hardware measurements are executed to reveal the asymmetric coexisting bifurcations and the phenomenon of multi-stability. The memristive Jerk circuit has three equilibrium points of a pair nontrivial equilibrium points of asymmetric unstable saddle-foci and a zero equilibrium point of unstable saddle-focus, which leads to the occurrence of asymmetric coexisting bifurcations and asymmetric local attraction basins. The asymmetrical bifurcations are numerically disclosed by 1-D/2-D bifurcation plots, Lyapunov spectrum, and phase plane trajectories. Multi-stability with asymmetric coexisting attractors under two sets of system parameters are demonstrated as examples by local attraction basins and phase plane trajectories. Thereafter, experimental circuit prototype employing discrete components is manually welded and hardware measurements are executed to validate the numerical simulations.     

Mode selection in a neuron driven by Josephson junction current in presence of magnetic field

Josephson junction is an active electric component and its channel current can be adjusted by external magnetic field, which can trigger additive phase error along the junction. From physical viewpoint, the Josephson junction can capture and release field energy when it is exposed to a magnetic field, and this time-varying current can be used to excite neural circuit for generating target firing patterns. In this paper, a Josephson junction is connected to a simple neural circuit, which is made of a capacitor, induction coil, a nonlinear resistor, two linear resistors and one constant voltage source in the branch, and the improved neural circuit is adjusted to percept external magnetic field and estimate the potential application of Josephson junction in nonlinear circuits. Bifurcation analysis is applied to explore the mode selection and dynamics dependence on parameters setting in the biophysical neural circuits. Furthermore, the neural circuit is exposed to external magnetic field and its physical effect is estimated by applying scale transformation on the variables and parameters in the neural circuit. It is confirmed that the neural circuit can be controlled and the neural activity shows distinct mode transition by taming the intensity (or angular frequency in periodic field) of external magnetic field. This kind of neural circuit can be further used as smart sensor for detecting weak magnetic field.     

Crystallization behavior and electroactive properties of PVDF,P(VDF-TrFE) and their blend films

PVDF, poly(vinylidene fluoride), as a semi-crystalline polymer, has interesting electroactive properties but usual melt and solution processing techniques result in its thermodynamically favored non-polar α-phase. By comparison, poly(vinylidene fluoride-trifluoroethylene) P(VDF-TrFE), PT for short, directly crystallizes in the polar β-phase under the same conditions as PVDF. In this study, blend thin films comprising PVDF and P(VDF-TrFE) were prepared by solvent casting method. The difference in the crystallization behavior is comprehensively investigated between the polymers: PVDF, P(VDF-TrFE), and the resulting blend films. It is found that replacement of the fluoride atom in TrFE monomer induces a strong steric hindrance that may alter the crystallization process to become more favorable for nucleation of the PVDF β-phase. To figure out the effect of TrFE content on the crystallization behavior and electroactive properties, films with different blend ratios of PVDF and P(VDF-TrFE) were prepared. We found that the PVDF films exhibit higher crystallization activation energy (ΔE) as PT content increases. The atomic force microscopy (AFM) in the piezoresponse force microscopy (PFM) mode illustrated that P5T5 films with equal contents of PVDF and P(VDF-TrFE) induced the highest d₃₃ values.