[Study on multi-angular polarized spectrum characteristics of leaf based on some indoor experimental data].

In the present study, we acquired multi-angular polarized spectrum of three kinds of leaves with different surface structures, and calculated the multi-angular spectral degree of polarization DOP based on Stokes parameters to explore its variation tendency with wavelength and the relationship between the leaf polarized reflectance and its physiological parameters and the relative observational geometric condition. The results show that although the spectral degree of polarization of the 3 kinds of leaves has obvious differences in value because of the leaf surface structures, the general trend of the DOP curve keeps consistent, and this trend could be explained by analyzing the properties of both specular and diffuse components of the leaf reflectance. The peak value of the DOP appears in the specular direction of the principal plane, and grows with the increase in the incident zenith angle. The analysis of the data demonstrates that compared to the other two experimental bands, the near infrared band shows a better discrimination in showing the relationship between DOP and the observational geometric configuration for all the three kinds of leaves, but the value of the DOP is smaller. Considering the effect of variation in chlorophyll content, DOP of the red band has more stable value than the near infrared band, whereas the water content has barely influence in both of the bands.

[Morphological study on early development of brain derived neurophic factor-positive neurons in the frontal lobe of human fetus].

OBJECTIVE: To investigate the growth and development of brain derived neurophic factor(BDNF)-positive neurons in the frontal lobe of human fetus. METHODS: The expression of the BDNF-positive neurons in the frontal lobe of human fetus in the 2(nd),3(rd),and 4(th) month of gestation were observed with the streptavidin-biotin-complex/immunoperoxidase(SABC)method. RESULTS: By the second month of gestation,BDNF-positive neurons were seen in the subventricular layer of the frontal lobe of cerebellum.By the third month of gestation,BDNF-positive neurons in the central layer were in various shapes,with big nucleus,less cytoplasm,and small processes.By the fourth month of gestation,BDNF-positive neurons in the central layer grew larger in size,cytoplasm increased,the BDNF-positive expression was enhanced with deeper dyeing,and the nerve fibers and particles were distributed between neurons;also,the BDNF-positive neurons were seen in the marginal layer of the frontal lobe of cerebrum. CONCLUSION: BDNF-positive neurons may participate in the early development of the frontal lobe of cerebrum of human fetus.

[Inversion of winter wheat water content with the relationship between canopy parameters and spectra based on different irrigations].

In order to monitor the canopy water content of winter wheat, canopy spectrums of winter wheat with narrow-band were resampled to broad-band according to relative spectral response (RSR) function of TM5. And then, normalized different water index (NDWI) and simple water index (WI) were calculated with broad-band reflectance. Fuel moisture content (FMC) and equivalent water thickness for canopy (EWTc) were got using dry weight, fresh weight and leaf area (index). The results show that b7 of TM5 is better than b5 in inversing canopy water content of winter wheat. Meanwhile, NDWI is more suitable than WI. Suitable fitting equations are built with NDWI (b4, b7) for FMC and EWTc, whose R2 reaches to 0.576 9 and 0.695 6, respectively. Finally, the spatial mapping of canopy water content is done with fitting equations. The results demonstrate that canopy water content of winter wheat is high in west and low in east in the studied area, and it's high in booting stage and low in milk stage.

[Modeling polarimetric BRDF of leaves surfaces].

The purpose of the present paper is to model a physical polarimetric bidirectional reflectance distribution function (pBRDF), which can character not only the non-Lambertian but also the polarized features in order that the pBRDF can be applied to analyze the relationship between the degree of polarization and the physiological and biochemical parameters of leaves quantitatively later. Firstly, the bidirectional polarized reflectance distributions from several leaves surfaces were measured by the polarized goniometer developed by Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences. The samples of leaves include two pieces of zea mays L. leaves (young leaf and mature leaf) and a piece of E. palcherrima wild leaf. Non-Lambertian characteristics of directional reflectance from the surfaces of these three leaves are obvious. A Cook-Torrance model was modified by coupling the polarized Fresnel equations to simulate the bidirectional polarized reflectance properties of leaves surfaces. The three parameters in the modified pBRDF model, such as diffuse reflectivity, refractive index and roughness of leaf surface were inversed with genetic algorithm (GA). It was found that the pBRDF model can fit with the measured data well. In addition, these parameters in the model are related with both the physiological and biochemical properties and the polarized characteristics of leaves, therefore it is possible to build the relationships between them later.