Some comments on the electrostatic forces between circular electrodes

We study the force between two circular electrodes in different configurations. A formula analogous to Kelvin's formula for the spheres is given in the case of equal disks held at the same potential and when one plate is earthed. An expression for the force at short distance between two arbitrarily charged disks is found: the generic case shows a logarithmic repulsive force, also for disks carrying charges of opposite sign. Some numerical computations support the results. A classification for the possible behaviors of the force is proposed on the basis of a decomposition of the capacitance matrix. It is shown that the forces depend strongly on the dimensionality of the contact zone between the conductors. The analysis is supported by a numerical computation carried for the case of two disks of different radii.     

Strategies for using cellular automata to locate constrained layer damping on vibrating structures

It is often hard to optimise constrained layer damping (CLD) for structures more complicated than simple beams and plates as its performance depends on its location, the shape of the applied patch, the mode shapes of the structure and the material properties. This paper considers the use of cellular automata (CA) in conjunction with finite element analysis to obtain an efficient coverage of CLD on structures. The effectiveness of several different sets of local rules governing the CA are compared against each other for a structure with known optimum coverage—namely a plate. The algorithm which attempts to replicate most closely known optimal configurations is considered the most successful. This algorithm is then used to generate an efficient CLD treatment that targets several modes of a curved composite panel. To validate the modelling approaches used, results are also presented of a comparison between theoretical and experimentally obtained modal properties of the damped curved panel.     

关于表述空化场强弱术语的讨论

声空化是声学中特别是超声学中一个极其重要的物理现象。然而,尽管对于声空化的研究已经有着极长的历史,但仍然有一些极基础的理论问题有待解决。如何来描述或表征声空化状态的强弱程度,就是这样一类的问题。该文对所谓的“空化强度”概念提出质疑,并对影响声空化现象的一些因素做出分析,相应地指出解决问题的一些建议,以期人们对这个无论在理论研究和实际应用方面都有重要意义的问题深入研究。     

一种基于高斯拟合的衍射光斑峰值位置的定位方法

基于衍射理论的分块镜共相位误差检测中,衍射光斑最高峰峰值位置的定位精度直接影响最终的测量精度,峰值定位精度受限于CCD的像元尺寸。针对衍射光斑的特点及最高峰峰值位置亚像元的定位精度要求,提出了基于高斯拟合的最高峰峰值位置的定位方法。在采样间距为5μm,采样点在10个左右的情况下,定位精度高于600nm,与传统的质心法及Hilbert变换法相比,精度可以提高20%以上,且鲁棒性好。实验结果表明,该方法是一种有效的亚像元精度的峰值定位方法,为提高共相位误差的测量精度提供有效途径。     

Some aspects of conformal field theories on the plane and higher genus Riemann surfaces

We review some aspects of conformal field theories on the plane as well as on higher genus Riemann surfaces.     

New scheme on how to realize quantum NOT gate

Recently, some schemes on how to realize quantum NOT gate have been reported. In this paper, we theoretically propose a new scheme by means of quantum theory. Here we use a quantum coin as a quantum NOT gate and its logic function is realized by the quantum game theory. In our schemes, classical noise does not disturb the realization of quantum NOT gate.     

Complementary method to locate atomic coordinates by combined searching method of structure-sensitive indexes based on bond valence method

Bond valence method illustrates the relation between valence and length of a particular bond type. This theory has been used to predict structure information, but the effect is very limited. In this paper, two indexes, i.e., global instability index(GII) and bond strain index(BSI), are adopted as a judgment of a search-match program for prediction. The results show that with GII and BSI combined as judgment, the predicted atom positions are very close to real ones. The mechanism and validity of this searching program are also discussed. The GII BSI distribution contour map reveals that the predicted function is a reflection of exponential feature of bond valence formula. This combined searching method may be integrated with other structure-determination method, and may be helpful in refining and testifying light atom positions.     

Herman-wallis factors for higher overtone bands: Application to HCl

Theoretical expressions for the Herman-Wallis factors in terms of the Dunham potential-energy parameters and dipole-moment coefficients were derived for higher overtone bands by the method of computer algebra. These results were applied to an analysis of the vibration-rotational intensities of HCl, leading to a good fit of the data and a dipole-moment function that is improved and extended by comparison with previous results.     

Gold-composite electrodes for hydrocarbon sensors based on YSZ solid electrolyte

In potentiometric zirconia based sensors gold electrodes show a high sensitivity for hydrocarbons (HC's) when the measurements are carried out in non equilibrated oxygen containing gas mixtures at temperatures <700 °C. This behaviour explained by mixed potential theory is not stable and depends strongly on preparation and particularly on measuring conditions. To modify the electrode behaviour composites consisting of gold and gallium oxide were investigated. Gold pastes with different amount of Ga₂O₃ were prepared and screen printed on YSZ pellets. After sintering at defined temperatures between 900 and 950 °C the cells were tested regarding the electrode behaviour in a C₃H₆, O₂ gas mixture using a platinum air reference electrode. These composite electrodes show as compared with pure gold an enhanced sensitivity at low propylene concentrations and a time-independent characteristic at high concentrations of C₃H₆. The optimal composition is found to be at 20 mass-% Ga₂O₃. This electrode can be treated in reducing gases at temperatures 850 °C without changing its characteristics. Paper presented at the 7th Euroconference on Ionics, Calcatoggio, Corsica, France, Oct. 1–7, 2000.     

Effect of electrodeposition modes on ruthenium oxide electrodes for supercapacitors

With developments in energy storage devices, supercapacitors are gaining more attraction because of their potential to excel batteries shortly. In this work, ruthenium oxide (RuO₂) has been deposited on stainless steel and studied the influence of surface modification of solid electrodes on capacitance properties. Hydrous ruthenium oxide was plated by different modes such as potential sweep method (cyclic voltammetric), constant potential method (chronoamperometry) and optimised potential pulse method using a recently reported precursor material namely ruthenium nitrosylsulfate (RuNS). The structural information and morphology of electrodeposits were characterised by X-ray diffractometer and scanning electron microscope respectively. The XRD studies indicate a poor crystalline state for RuO₂ in all the modes of deposition but can contribute to a higher surface area when compared to a highly crystalline form. The SEM analysis revealed the formation of surface modification concerning the change of potential mode. Mud-cracked morphology, spherical particles and dendrimeric morphology observed on chronoamperometry, potential pulse and cyclic voltammetry respectively. Electrochemical studies were also conducted on the samples to assess their performance for supercapacitor applications. The spherical particles of hydrous RuO₂ show high performance of capacitance behaviour 1180 F/g in 0.5 M H₂SO₄ at the scan rate of 5 mV/s. Dendrimeric morphology and mud-cracked morphology shows 573 F/g and 546 F/g respectively in same 0.5 M H₂SO₄ at the scan rate of 5 mV/s. The studies reveal that RuO₂ electrodes can be exploited for their outstanding capacitive behaviour by properly controlling the morphology of the deposits.     

Evidence for higher order asymptotic freedom corrections to deep inelastic scattering

We find new evidence for higher order asymptotic freedom corrections to the moments of the proton structure function in electron, muon scattering for spins n ? 4. We show that it is unlikely that this effect can be associated in any simple way with higher-twist effects.     

Search for neutron production during heavy water electrolysis on palladium electrodes

The results are presented from a number of experiments in search for neutrons from the heavy water electrolysis with use of different palladium cathodes. The upper limit for the yield of neutrons from a cell with a 2.34 cm³ palladium cathode, which operated continuously for seven days, is 0.2 neutron/s (0.01 neutron/s per gram of palladium). This limit is 10⁵ times lower than the yield claimed recently by Fleischamann and Pons.     

Composites of olive-like manganese oxalate on graphene sheets for supercapacitor electrodes

MnC₂O₄/graphene composites are prepared by a facile hydrothermal reaction with KMnO₄ using ascorbic acid as a reducing agent. Olive-like MnC₂O₄ particles are distributed uniformly on the surface of graphene sheets. The composites are evaluated as supercapacitor electrodes, which show that the specific capacitance of MnC₂O₄/graphene composites is 122 F g^?1, more than twice as high as that of free MnC₂O₄ at a current density of 0.5 A g^?1. In addition, this composite material exhibits an excellent cycle stability with the capacitance retention of 94.3 % after 1,000 cycles.     

Some identities on the q-Euler polynomials of higher order and q-stirling numbers by the fermionic p-adic integral on ℤ p

A systemic study of some families of q-Euler numbers and families of polynomials of Nörlund type is presented by using the multivariate fermionic p-adic integral on ? _p . The study of these higher-order q-Euler numbers and polynomials yields an interesting q-analog of identities for Stirling numbers.     

Highly conductive molecular junctions based on direct binding of benzene to platinum electrodes

Highly conductive molecular junctions were formed by direct binding of benzene molecules between two Pt electrodes. Measurements of conductance, isotopic shift in inelastic spectroscopy, and shot noise compared with calculations provide indications for a stable molecular junction where the benzene molecule is preserved intact and bonded to the Pt leads via carbon atoms. The junction has a conductance comparable to that for metallic atomic junctions (around 0.1-1G0), where the conductance and the number of transmission channels are controlled by the molecule's orientation at different interelectrode distances.