Influence of the Transition to Nanoscaled State on Electrochemical Properties of LaMnO3+δ Oxide

2008 ◽  
Vol 273-276 ◽  
pp. 354-360 ◽  
Author(s):  
G.A. Kozhina ◽  
A.N. Ermakov ◽  
V.B. Fetisov ◽  
A.V. Fetisov ◽  
Anatoly Yakovlevich Fishman ◽  
...  
Keyword(s):  
Electrochemical Properties ◽  
Intermediate Stage ◽  
Formation Mechanisms ◽  
Size Factor ◽  
Carbon Paste ◽  
Stationary Potential ◽  
Three Stages ◽  
The Difference ◽  
Perovskite Type ◽  
Electroactive Electrode

The electrochemical behavior of perovskite type LaMnO3 (LMO) oxides with different mean particle size was studied by voltammetry with the use of a carbon paste electroactive electrode. Three stages of electrochemical reduction were recognized. The first two of them are related to the release of oxygen from the crystal lattice in the range of two side nonstoichiometry of LaMnO3±δ whereas the final stage is conditioned by the decomposition of LaMnO3-δ into new phases. The nature of these phases and their formation mechanisms are different for nano- and microparticles. The utmost size effect appears on cathodic curves recorded from the stationary potential. The effect is not only due to the size factor but also due to the difference in electrochemical properties of nano- and microparticles. While the decomposition of LaMnO3 microparticles proceeds into La2O3 and MnO oxides, the nanoparticles decompose through the intermediate stage of Mn3O4 formation in accordance with the transformation sequence principle.

LONG‐TIME RESPONSE PREDICTED BY EXACT ELASTIC RAY THEORY

Geophysics ◽  
1965 ◽  
Vol 30 (3) ◽  
pp. 363-368 ◽  
Author(s):  
T. W. Spencer
Keyword(s):  
Formal Solution ◽  
Intermediate Stage ◽  
Time Limit ◽  
Time Interval ◽  
Individual Response ◽  
Axially Symmetric ◽  
Long Time ◽  
The Difference ◽  
The Individual ◽  
Significant Figures

The formal solution for an axially symmetric radiation field in a multilayered, elastic system can be expanded in an infinite series. Each term in the series is associated with a particular raypath. It is shown that in the long‐time limit the individual response functions produced by a step input in particle velocity are given by polynomials in odd powers of the time. For rays which suffer m reflections, the degree of the polynomials is 2m+1. The total response is obtained by summing all rays which contribute in a specified time interval. When the rays are selected indiscriminately, the difference between the magnitude of the partial sum at an intermediate stage of computation and the magnitude of the correct total sum may be greater than the number of significant figures carried by the computer. A prescription is stated for arranging the rays into groups. Each group response function varies linearly in the long‐time limit and goes to zero when convolved with a physically realizable source function.

Solvent effect on synthesis of perovskite-type La1−xCaxCoO3 and their electrochemical properties for oxygen reactions

2000 ◽  
Vol 35 (12) ◽  
pp. 1955-1966 ◽  
Author(s):  
A. Kahoul ◽  
A. Hammouche ◽  
F. Nâamoune ◽  
P. Chartier ◽  
G. Poillerat ◽  
...  
Keyword(s):  
Solvent Effect ◽  
Electrochemical Properties ◽  
Perovskite Type

The mechanism of work-hardening and slip-band formation

1957 ◽  
Vol 242 (1229) ◽  
pp. 147-159 ◽  
Keyword(s):  
Single Crystals ◽  
Slip Band ◽  
Work Hardening ◽  
Stage I ◽  
Polycrystalline Materials ◽  
Temperature Dependent ◽  
Band Formation ◽  
Slip Bands ◽  
Three Stages ◽  
The Difference

A summary is given of some present ideas on the mechanism of work-hardening of single crystals and polycrystalline materials. In particular, the difference is stressed between the three stages of hardening: stage I, or easy glide; stage II, the region of rapid hardening accompanied by short slip lines; and stage III, the region of slow or parabolic hardening which is temperature-dependent and in which long slip bands are formed.

Novel synthesis and electrochemical properties of perovskite-type NaFeF3 for a sodium-ion battery

2012 ◽  
Vol 198 ◽  
pp. 389-392 ◽  
Author(s):  
Ayuko Kitajou ◽  
Hideyuki Komatsu ◽  
Kuniko Chihara ◽  
Irina D. Gocheva ◽  
Shigeto Okada ◽  
...  
Keyword(s):  
Electrochemical Properties ◽  
Sodium Ion ◽  
Sodium Ion Battery ◽  
Novel Synthesis ◽  
Perovskite Type

On the difference of aerosol hygroscopicity between high and low RH environment in the North China Plain

2021 ◽  
Author(s):  
Jingnan Shi ◽  
Juan Hong ◽  
Nan Ma ◽  
Qingwei Luo ◽  
Hanbing Xu ◽  
...  
Keyword(s):  
Chemical Composition ◽  
North China Plain ◽  
North China ◽  
Experimental Period ◽  
Formation Mechanisms ◽  
Large Contribution ◽  
The North ◽  
The North China Plain ◽  
The Difference ◽  
Aerosol Hygroscopicity

<p>Simultaneous measurements of aerosol hygroscopicity and chemical composition were performed at a suburban site in the North China Plain in winter 2018 using a self-assembled hygroscopic tandem differential mobility analyzer (H-TDMA) and a capture-vaporizer time-of-flight aerosol chemical speciation monitor (CV-ToF-ACSM), respectively. During the experimental period, aerosol particles usually show an external mixture in terms of hygroscopicity, with a less hygroscopic particles mode (LH) and a more hygroscopic mode (MH). The average ensemble mean hygroscopicity parameter (κ<sub>mean</sub>) are 0.16, 0.18, 0.16, and 0.15 for 60, 100, 150, and 200 nm particles, respectively. Two episodes with different RH/T conditions and secondary aerosol formations are distinguished. Higher aerosol hygroscopicity is observed for all measured sizes in the high RH episode (HRH) than in the low RH episode (LRH). In LRH, κ decreases as the particle size increases, which may be explained by the large contribution of non- or less-hygroscopic primary compounds in large particles due to the enhanced domestic heating emissions at low temperature. The number fraction of LH mode at 200 nm even exceeds 50%. Closure analysis is carried out between the HTDMA-measured κ and the ACSM-derived hygroscopicity using different approximations for the hygroscopic parameters of organic compounds (κ<sub>org</sub>). The results indicate that κ<sub>org</sub> is less sensitive towards the variation of its oxidation level under HRH conditions but has a stronger O: C-dependency under LRH conditions. The difference in the chemical composition and their corresponding physical properties under different RH/T conditions reflects potentially different formation mechanisms of secondary organic aerosols at those two distinct episodes.</p>

Bainite

2015 ◽  
pp. 99-112
Keyword(s):  
Solute Drag ◽  
Lower Bainite ◽  
Transformation Product ◽  
Intermediate Temperature ◽  
Bainitic Transformation ◽  
Formation Mechanisms ◽  
Temperature Transformation ◽  
The Difference

Bainite is an intermediate temperature transformation product of austenite. This chapter describes the conditions under which bainite is likely to form. It discusses the effects of alloying on bainitic transformation, the difference between upper and lower bainite, and the influence of solute drag on bainite formation mechanisms. It also discusses the development of ferrite-carbide bainites and their effect on toughness, hardness, and ductility.

scholarly journals Study on the Origin and Fluid Identification of Low-Resistance Gas Reservoirs

Geofluids ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Zhou Yuhui ◽  
Hu Qingxiong ◽  
Liu Wentao ◽  
Wu Zhiqi ◽  
Yan Yule ◽  
...  
Keyword(s):  
Technical Problem ◽  
Laboratory Data ◽  
Gas Content ◽  
Formation Mechanisms ◽  
Gas Reservoirs ◽  
Gas Reservoir ◽  
Fluid Identification ◽  
Low Resistance ◽  
Neutron Porosity ◽  
The Difference

The Wu 2 section of the Ke017 well block is a low-resistance gas reservoir with ultralow porosity and low permeability. The comprehensive analysis of rock lithology, physical properties, sedimentary characteristics, and gas content demonstrated that the development of micropores in illite/smectite dominated clay minerals together with the resulted additional conductivity capability and complex reservoir pore structures, as well as the enrichment of self-generating conductivity minerals like zeolites and pyrite which were the formation mechanisms of low-resistance gas layers in the Wu 2 section. A low-resistance gas reservoir has poor physical property, and it is difficult to distinguish the oil layer from the dry, gas, or water layers. In this paper, based on well/mud logging data and laboratory data, by taking advantages of the “excavation effect” of neutron gas and the dual-lateral resistivity difference between different depths, we successfully established a set of low-contrast log response methods for the identification and evaluation of oil layer and formation fluids. For a gas layer, the difference between neutron porosity and acoustic (or density) porosity is smaller than 0 and the difference in dual-lateral resistivity is greater than 0. For a water layer, the neutron porosity is similar to the acoustic (or density) porosity and the dual-lateral resistivity difference will be less than 0. While for a dry layer or a layer with both gas and water, the difference in porosity as well as dual-lateral resistivity is very small. The proposed method effectively solves the technical problem of oil layer and formation fluid identification in low-resistance gas reservoirs.

Sign in / Sign up

Export Citation Format

Share Document