Valence orbital method of calculating harmonic emission from diatomic molecule

We present a valence orbital method of calculating high-order harmonic generation from a diatomic molecule with arbitrary orientation by using a space rotation operator. We evaluate the effects of each valence orbital on harmonic emissions from N₂ and O₂ molecules in detail separately. The calculation results confirm the different properties of harmonic yields from N₂ and O₂ molecules which are well consistent with available experimental data. We observe that due to the orientation dependence of \sigma and \pi orbitals, the bonding orbital (\sigma _{2pz} )^2 of N₂ determines the maximum of harmonic emission when the molecular axis of N₂ is aligned parallel to the laser vector, and the magnitude of the high harmonic signal gradually weakens with the orientation angle of molecular axis increasing. But for O₂ molecule the antibonding orbitals (\pi _{2py}^\ast )^1 and (\pi _{2pz}^\ast )^1 contribute to the maximum of harmonic yield when O₂ is aligned at 45^{\circ} and bonding orbitals (\pi _{2py} )^2 and (\pi _{2pz} )^2 slightly influence the orientation angle of maximum of harmonic radiation not exactly at 45^{\circ}.     

Direct evidence for conduction pathways in a solid electrolyte

The emission of silver ions from the apex of an amorphous electrolyte tip has been investigated by field ion microscopy. The ion emission patterns show discrete nanometer-sized spots. We present evidence that they represent the termination of bulk ion conduction pathways at the solid-vacuum interface. The analysis of the signals from individual emission sites suggests the existence of a network of such pathways in the solid. Auto- and cross-correlation measurements of the currents from individual sites provide quantitative information on the microscopic dynamics of charge transport in solid electrolytes as well as on the lateral extent of the pathway network.     

Regenerative energy conversion using oxygen solid electrolytes

A heat machine is studied of regenerative type, based on solid electrolytes with unipolar oxygen conductivity. The achieved specific power is about 0.2 mW/cm². Electrical characteristics are derived as a function of temperature, pressure and gas composition in the working chamber of the converter. Factors which influence the specific power as well as optimal regimes for the functioning of the device are determined.     

Optimization of divalent magnesium ion conduction in phosphate based polycrystalline solid electrolytes

A highest Mg²⁺ ion conducting polycrystalline solid electrolyte was successfully realized by improving the characteristics of both grain bulks and grain boundaries simultaneously. The former improvement was achieved by making a solid solution to substitute cation site for higher valent one to create Mg²⁺ ion vacancies in grain bulks. The latter was realized by obtaining a composite in such a manner to microscopically deposit the insulating secondary phase in grain boundaries. By combining above mentioned two effects, the optimization of Mg²⁺ ion conductivity at around 800 °C was effectively achieved to reach the total Mg²⁺ ion conductivity of approximately 10⁻² S·cm⁻¹ which is applicable in a practical range.     

P-Type electronic conduction in CeO2- and LaGaO3-based solid electrolytes

Modifications of the e.m.f. and faradaic efficiency techniques, taking into account electrode polarization in the measuring cells, in combination with the use of electrodes having sufficiently high polarization resistances enable a precise determination of minor electronic contributions to the conductivity of solid electrolytes. These methods were used to determine the p-type conductivity of compositions based on La(Sr)Ga(Mg)O_3-δ (LSGM) and Ce(Gd)O_2-δ (CGO) at 900–1270 K. The oxygen ion transference numbers of these materials under oxygen/air gradient vary in the range 0.999–0.970, increasing with decreasing temperature. Substitution of 2 % gadolinium in Ce_0.80Gd_0.20O_2-δ with praseodymium was found to increase the electron-hole conduction by 2.5 – 4 times. At temperatures above 700 K, both the partial oxygen ionic and p-type electronic conductivities of LaGaO₃-based phases are higher than those in CGO. The electron-hole transport in LSGM tends to increase with the magnesium concentration, while the activation energy is essentially independent of composition. Electronic conduction in CGO and LSGM electrolytes was also found to be influenced by the ceramic microstructure. Paper presented at the 8th EuroConference on Ionics, Carvoeiro, Algarve, Portugal, Sept. 16–22, 2001.     

Information storage using nanoscale electrodeposition of metal in solid electrolytes

Programmable metallization cell (PMC) memory is based on the electrochemical control of nanoscale quantities of metal in thin films of solid electrolyte. It shows great promise as an ultra-scalable solid state non-volatile memory as it requires low programming voltage and current, and has the ability for the storage cells to be physically sized at minimum lithographically defined dimensions. Scalability issues will be discussed in the context of recent findings relating to the nanostructure of the electrolyte and results obtained from small-geometry devices based on Ag–Ge–Se nano-phase separated material.     

Some innovative technologies using solid electrolytes in measuring gas compositions

Solid electrolytes have received considerable scientific attention and assumed important technological significance in recent years, due to potential practical applications in fuel cells, batteries, electrochromics, process control, sensors and environmental protection. Use of solid electrolytes for developing electrochemical gas sensors is a well established field with successful commercial applications related mainly to oxygen measurements. Discovery of new solid electrolytes have led to new areas of development and applications such as hydrogen monitoring. Applicability of solid electrolytes have also been extended to species which are not ionically mobile in the electrolyte by use of auxiliary phases. More recently, significant progress in sensing of molecular species such as CO₂, SO₂, SO₃, NO, NO₂, HCl, H₂O and HF have been achieved by interfacing 2 or more electrolytes in electrochemical chains and/or by using auxiliary phases, semi-permeable coatings or in-situ catalysts to promote the desired electrode reactions. Paper presented at the 4th Euroconference on Solid State Ionics, Renvyle, Galway, Ireland, Sept. 13–19, 1997     

Valence and conduction bands in MPS3 layered compounds studied by synchrotron radiation

Summary With the resonant photomeission technique we investigated the valence bands of FePS₃ and NiPS₃. The experimental results, support the ionic picture of the compounds and our previous identification of the valence band structures. The structures rapidly varying in intensity when the excitation energy is scanned across the Fe and NiM _2,3 absorption edge are associated to the transition metal 3d states; the nonresonating features are ascribed to the (P₂P₆)⁴⁻ cluster states. With the yield technique we measured the high-resolution absorption spectra of the phosphorus and sulphur inner-core levels in Mn, Fe and Ni thiophosphates. TheL _2,3(P) andL _2,3(S) spectra are similar to each other in all the compounds and are interpreted in terms of the projected density of states of the conduction bands derived from the (P₂S₆)⁴⁻ cluster states. To speed up publication, the authors of this paper have agreed to not receive the proofs for correction.     

Coulometric titrations of electrolytes in water by a solid state ionic device using Nafion and Tosflex membranes

A solid state ionic device to titrate electrolytes in water was produced, and the performance of the device was examined. The device named the coulometric titration apparatus is a three-component electrochemical cell like an electrodialyzer. The central component, the analyzing room, is a container of the sample solution. The sample solution, 10⁻¹ M H₂SO₄, NaOH, Na₂SO₄, or 10⁻⁷–10⁻² M Na₂SO₄, is separated from the cathode and the anode room solutions, 10⁻² M H₂SO₄, NaOH, or Na₂SO₄, by Nafion-117 and Tosflex IE-SF34 membranes working as the anion and the cation blocking electrodes, respectively. The quantity of electricity to extract whole electrolytes in the sample solution is evaluated from the peak area of the titration curve. The sample concentration is successfully determined by the calibration curve method, with the quantity of electricity and the sample volume (6 ml) in the range from 10⁻¹ to 10⁻⁵ M.     

Ion dynamics in solid electrolytes described by the concept of mismatch and relaxation

Abstract

Below the far-infrared frequency regime, conductivity spectra of crystalline ion conductors like RbAg₄I₅ and others display remarkably uniform characteristics. Well-known approximations include the universal dynamic response (UDR) and the nearly constant loss (NCL) behaviour. We now present a new non-power-law, non-KWW master curve. Its shape is shown to be equivalent to a proportionality between two particular functions of time. These functions are interpreted as rates of mismatch relaxation via the so-called single-particle and many-particle routes. The proportionality of relaxation rates is the central statement of the concept of mismatch and relaxation (CMR).     

Complex conductivity of solid electrolytes in the microwave range

Experimental results of the microwave complex conductivity of β-CuBr solid electrolyte are presented along with a simple model which closely fits the data. The mean duration of the jumps is estimated to be roughly 2 × 10^-11 s.     

Relation between proton and hole conduction in SrCeO3-based solid electrolytes under water-containing atmospheres at high temperatures

Electrical conduction in the solid proton electrolyte based on SrCeO₃ was studied under water-containing atmospheres at high temperatures. The change of conductivity was measured systematically as a function of the concentration of the dopant or of the partial pressures of water vapor and oxygen. Since the conduction in the oxides was not purely protonic but partially electronic, these conductivities were determined separately using a steam concentration cell. It was observed that the proton conductivity increased in proportion to P^{$\text{1}\text{2}$_H2O} and was independent of P_O2. It was also recognized that the electronic conduction present in the oxides was due to holes and the hole conductivity followed the P^{$\text{1}\text{4}$}_O2 law. A possible model for the proton formation in the oxides is discussed and it is proposed that the protons might be produced from water vapor at the expense of holes.     

On calculating scattering phase shifts by the generator coordinate method

The generator coordinate equations for scattering phase shifts are solved for α-α scattering. Calculations are made in the coordinate representation and the results agree well with those obtained by a more laborious procedure which is formulated in the momentum representation. The results disagree with another calculation in the coordinate representation, where the scattering boundary condition is introduced less accurately.     

Transient heat conduction analysis using the MLPG method and modified precise time step integration method

The meshless local Petrov–Galerkin (MLPG) method in conjunction with the modified precise time step integration method in the time domain is proposed for transient heat conduction analysis in this paper. The MLPG method is often referred to as a truly meshless method because it requires no elements or background cells for either field interpolation or background integration. Local weak forms are developed using weighted residual method locally from the partial differential equation of transient heat conduction. In order to simplify the treatment of essential boundary conditions, the natural neighbour interpolation (NNI) is employed for the construction of trial functions. Moreover, the three-node triangular FEM shape functions are taken as test functions to reduce the order of integrands involved in domain integrals. The semi-discrete heat conduction equation is solved numerically with modified precise time step integration method in the time domain. The availability and accuracy of the present method for transient heat conduction analysis are tested through numerical examples.     

Screening of the deformation field in a solid by point defects

It is demonstrated that in an isotropic infinite solid body with a high concentration of point defects, the deformation produced by a test defect decreases with the distance from it according to a law similar to that of the decrease in the potential of a point charge with Debye screening.     

Dramatic reduction in the densification temperature of garnet-type solid electrolytes

Cubic garnet Li₇La₃Zr₂O₁₂ (LLZO) and similar compositions of fast ion-conducting solid-state electrolytes have shown great potential for the development of high-energy-density solid-state Li-ion batteries. Although these materials have shown unprecedented ionic conductivities and chemical stability, these materials require high processing temperatures for synthesis. For many of the common compositions of LLZO, temperatures above 1000 °C are required to form the cubic garnet phase and to achieve high conductivities. Therefore, lowering the processing temperatures of these materials is of great interest for the purposes of scalability and fabrication. It has been reported that a Bi co-dopant not only stabilizes the cubic garnet phase but also lowers the densification temperature. In this study, Li₆La₃ZrBiO₁₂ (LLZBO) was prepared by a rapid-induction hot-pressing technique and characterized using a variety of techniques, including X-ray diffraction, scanning electron microscopy, and Raman spectroscopy. We demonstrate the ability to synthesize phase-pure LLZBO with higher relative densities (~?94%) than can be achieved by pressure-less sintering methods, at pressing temperatures of only 850 °C. The ionic conductivity was measured to be 0.1 mS cm^?1, which is comparable to the best reported conductivities of high-density LLZO. This demonstrates the ability to fabricate dense, phase-pure, and high-conductivity LLZBO at temperatures significantly lower than other garnet compositions, which will prove useful for scalability and reducing reactivity with cathodes during densification.     

一种获取双原子分子的转动常数的方法

本文给出了对于任何双原子分子或双原子自由基分子,由其振动常数结合RKR方程、结合从头计算,获得势能曲线及其转动常数的方法.并对CN的基态和激发态进行了计算,结果与实验值符合得非常一致.A     

Uranium analysis by neutron induced fissionography method using solid state nuclear track detectors

In this study total twenty samples (eight reference materials and twelve sediment samples) were analysed for their uranium content which is in the range of 1–17 μg/g, by neutron induced fissionography (NIF) method using solid state nuclear track detectors (SSNTDs) in comparison with the results of neutron activation analysis (NAA), delayed neutron counting (DNC) technique or fluorometric method. It is found that NIF method using SSNTDs is very sensitive for analysis of uranium.     

Improvement of plasma-sprayed YSZ electrolytes for solid oxide fuel cells by alumina addition

Atmospheric plasma spray is a fast and economical process for deposition of yttria-stabilized zirconia (YSZ) electrolyte for solid oxide fuel cells. YSZ powders have been used to prepare plasma-sprayed thin ceramic films on the metallic substrate employing plasma spray technology at atmospheric pressure. Alumina doping was employed to improve the structural characteristics and electrical properties of YSZ. The effect of alumina addition from 1 to 5 wt.% on the properties of plasma-sprayed YSZ films was investigated. It was found that the gas permeability of the Al-doped YSZ electrolyte layer reached a level of 8.6 × 10⁻⁷ cm⁴ gf⁻¹ s⁻¹, which is a necessary value for the practical operation of solid oxide fuel cells. Alumina doping considerably increased the ionic conductivity of plasma-sprayed YSZ. The open circuit voltage of the alumina-doped YSZ coating was approximately equal to the theoretical value for dense YSZ material.     

A method for calculating the absorption coefficient of a multi-layer absorbent using the electro-acoustic analogy

A theoretical method for calculating the absorption coefficient of the multi-layer absorbers composed of perforated plates, airspaces and porous materials is proposed. Initially, for multi-layer absorbers composed either of perforated plates and airspaces or perforated plates and porous materials, the acoustic impedance is calculated using an electro-acoustic analogy. Then, for multi-layer absorbers composed of perforated plates, airspaces and porous materials, the acoustic impedance is calculated using an iterative method. Finally, theoretical calculations for the absorption coefficient of three types of multi-layer absorbers composed of different materials and including perforated plates are carried out. The results are validated by experimental results.