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In order to solve the geometric offset caused by replacing the filter during imaging of multichannel spectral image data, a multichannel spectral image registration method based on SURF feature merged with maximum submatrix is proposed. Firstly, the feature of multichannel spectral image is extracted by SURF. Then, a perspective transformation is performed to obtain a preliminary registration image. For the problem of invalid areas with zero pixel values appearing at the boundary of the image after registration, the largest submatrix is used to detect the maximum inscribed rectangle of the image to remove the invalid boundary region, and maximize the reserved effective region information. Experimented was processed with multichannel imaging data of murals. Experimental results agree with the theoretic analysis and verified that the proposed registration method is better adapted to image scale and brightness changing. At the same time, it can avoid the influence of invalid regions generated by other registration methods on subsequent spectral reconstruction and color restoration which has better performance. [ABSTRACT FROM AUTHOR]

We developed a tree-ring width chronology from pine trees ( Pinus tabulaeformis and Pinus armandii) stand near the peaks of Huashan, Shaanxi, north-central China. Growth-climate response analyses showed that the radial growth of pine trees is mainly influenced by April-June precipitation. A model to reconstruct precipitation based on tree widths was constructed, accounting for 55 % of the instrumental variance during the period 1953-2012. Spatial correlation analyses between the reconstruction and observed gridded precipitation data shows that the seasonal precipitation reconstruction captures regional climatic variations over north China. Compared with the historical archives and other tree-ring records in north China, many large-scale drought events, linked to the El Niño-Southern Oscillation (ENSO), were found. Many of these events have had profound impacts on the people of north China over the past several centuries. Composite maps of sea surface temperatures and 500 hPa geopotential heights for selected extremely dry and wet years in Huashan show characteristics similar to those related to the ENSO patterns, particularly with regard to ocean and atmospheric conditions in the equatorial and north Pacific. Our 531-year precipitation reconstruction for Huashan provides a long-term perspective on current and 20th century wet and dry events in north China, and is useful to guide expectations of future variability, and helps us to address climate change. [ABSTRACT FROM AUTHOR]

Densities, viscosity and bubble-point vapor pressures for binary mixtures of dimethoxy methane and a hydrocarbon fuel (exo-tetrahydrodicyclopentadiene) were measured over the whole composition range. The excess molar volumes ( V m E ) and viscosity deviations (Δη) for the binary systems were calculated from the density and viscosity data. The Antoine equation was fitted with the experimental vapor pressures, and the corresponding parameters were calculated. Positive values of excess molar volumes, negative viscosity deviations and positive deviations from Raoult's law for the vapor pressures are observed. The three physical properties and the corresponding calculation results provide valuable information on the application and study of mixed liquid hydrocarbon fuels. [ABSTRACT FROM AUTHOR]

Measurements of density, viscosity and vapor pressure for binary mixtures of exo-tetrahydrodicyclopentadiene (JP-10) with isopropyl ether are reported at temperatures of (293.15, 298.15, 303.15, 308.15, and 313.15) K over the entire composition range. The excess molar volumes, viscosity deviation and excess Gibbs energies of activation for the binary systems were calculated from the experimental values and fitted with the Redlich-Kister equation. Isopropyl ether was added to enhance the vapor pressure of JP-10. Experimental vapor pressure data were correlated by the Antoine equation. Several semi-empirical equations were used to correlate the viscosity data. The McAllister equation gives relatively satisfactory results for the correlation. The experimental and correlated data could be used in the development of models for mixtures of hydrocarbons with oxygenates. [ABSTRACT FROM AUTHOR]