[The research of the relationship between snow properties and the bidirectional polarized reflectance from snow surface].

In the context of remote sensing, the reflectance of snow is a key factor for accurate inversion for snow properties, such as snow grain size, albedo, because of it is influenced by the change of snow properties. The polarized reflectance is a general phenomenon during the reflected progress in natural incident light In this paper, based on the correct measurements for the multiple-angle reflected property of snow field in visible and near infrared wavelength (from 350 to 2,500 nm), the influence of snow grain size and wet snow on the bidirectional polarized property of snow was measured and analyzed. Combining the results measured in the field and previous conclusions confirms that the relation between polarization and snow grain size is obvious in infrared wavelength (at about 1,500 nm), which means the degree of polarization increasing with an increase of snow grain size in the forward scattering direction, it is because the strong absorption of ice near 1,500 nm leads to the single scattering light contributes to the reflection information obtained by the sensor; in other word, the larger grain size, the more absorption accompanying the larger polarization in forward scattering direction; we can illustrate that the change from dry snow to wet snow also influences the polarization property of snow, because of the water on the surface of snow particle adheres the adjacent particles, that means the wet snow grain size is larger than the dry snow grain size. Therefore, combining the multiple-angle polarization with reflectance will provide solid method and theoretical basis for inversion of snow properties.

[Measurement and analysis of reflected information from crops canopy suffering from wind disaster influence].

The corn in the grain filling stage fell over in the central region of Jilin province by the Typhoon Bolaven influence. In order to determine the impact of falling over corn canopy on the reflected information, the hyperspectral reflectance was detected at different viewing zenith angles, at the same time, the polarized reflection was also measured. The results from the analysis by combining the reflection and polarization from corn canopy showed that the reflection of falling over corn is low in visible, while increases in the near infrared wavelength. The reflection from falling over corn canopy was more anisotropic than stand-up corn canopy. The reflected light was highly polarized, the polarization of corn canopy provided the probability for distinguishing between falling over corn and stand-up corn. This research provides a basis for estimating the disaster area and lost units.

[Quantitative analysis of the polarized reflection factor of influence of oil film on water surface and their interaction].

In order to extract more reflection characteristic information of oil film on water surface by using remote sensing technology, the authors measured and analyzed the multi-angle hyperspectral polarized reflection information of oil film based on the traditional remote sensing researches. The authors used polarization as the indicator of quantitative study, adopted a three-factor-three-level orthogonal test to analyze the incident angle, oil film thickness, band, and the influence of oil film on water surface from their interaction between each other. The results of variance analysis of this orthogonal test show that: the three factors and their interaction between each other all have an influence on the polarization of oil film; the interaction between incident angle and thickness of oil slick, and the interaction between band and thickness of oil slick both show a significant impact on polarization. That is to say, the research on oil film by using hyperspectral multi-angle polarized reflectance needs both the influence on polarization from each factor and their interaction.

[Analysis of influencing factors of snow hyperspectral polarized reflections].

Due to the need of snow monitoring and the impact of the global change on the snow, on the basis of the traditional research on snow, starting from the perspective of multi-angle polarized reflectance, we analyzed the influencing factors of snow from the incidence zenith angles, the detection zenith angles, the detection azimuth angles, polarized angles, the density of snow, the degree of pollution, and the background of the undersurface. It was found that these factors affected the spectral reflectance values of the snow, and the effect of some factors on the polarization hyperspectral reflectance observation is more evident than in the vertical observation. Among these influencing factors, the pollution of snow leads to an obvious change in the snow reflectance spectrum curve, while other factors have little effect on the shape of the snow reflectance spectrum curve and mainly impact the reflection ratio of the snow. Snow reflectance polarization information has not only important theoretical significance, but also wide application prospect, and provides new ideas and methods for the quantitative research on snow using the remote sensing technology.

[Study on mechanical factors involved in sports muscle injury].

Objective. To investigate the effect of eccentric strengthening (EC) exercise on muscular structure, plasma CK and biomechanical behavior under different mechanical loadings and to study the mechanical factors involved in sports muscle injury. Method. We developed an apparatus to do eccentric strength training with male SD rats under different mechanical loadings and to measure the biomechanical behavior. Result. No significant difference (P>0.05) of muscular structure, plasma CK and biomechanical behavior were found between high and low force groups. Conclusion. Skeletal muscle injury after cyclic EC with different mechanical loadings suggested that muscle damage is not simply a function of peak muscle force.