Mapping Fire Severity in Southwest China Using the Combination of Sentinel 2 and GF Series Satellite Images.

Fire severity mapping can capture heterogeneous fire severity patterns over large spatial extents. Although numerous remote sensing approaches have been established, regional-scale fire severity mapping at fine spatial scales (<5 m) from high-resolution satellite images is challenging. The fire severity of a vast forest fire that occurred in Southwest China was mapped at 2 m spatial resolution by random forest models using Sentinel 2 and GF series remote sensing images. This study demonstrated that using the combination of Sentinel 2 and GF series satellite images showed some improvement (from 85% to 91%) in global classification accuracy compared to using only Sentinel 2 images. The classification accuracy of unburnt, moderate, and high severity classes was significantly higher (>85%) than the accuracy of low severity classes in both cases. Adding high-resolution GF series images to the training dataset reduced the probability of low severity being under-predicted and improved the accuracy of the low severity class from 54.55% to 72.73%. RdNBR was the most important feature, and the red edge bands of Sentinel 2 images had relatively high importance. Additional studies are needed to explore the sensitivity of different spatial scales satellite images for mapping fire severity at fine spatial scales across various ecosystems.

[The effect of firing times on the chroma of tetragonal zirconia polycrystal by adding rare-earth oxides].

OBJECTIVE: The aim of this study is to evaluate whether the firing times affect the chroma of zirconia by adding rare-earth oxides. METHODS: Six kinds (S1, S2, S3, S4, S5, S6) of tooth-like yttria stabilized tetragonal zirconia polycrystal (Y-TZP) were available by introducing internal colorating technology, the color were gauged with ShadeEye NCC chromatometry instrument, and one-way ANOVA was used to analysis the color of each kind of tooth-like zirconia after 1, 2, 3, 4, 5 times firing individually. RESULTS: After 1, 2, 3, 4, 5 times firing respectively, the chromatic aberration ranged between 0.10-1.47 merely. The luminosity of three kinds (S1, S2, S6) of tooth-like zirconia were decreased (P < 0.05), the luminosity of the other three kinds (S3, S4, S5) of tooth-like zirconia were not obviously changed (P > 0.05), as for the hue and chroma, no significant differences were found (P > 0.05). CONCLUSION: There are no significant influence on the color of tooth-like Y-TZP after 1, 2, 3, 4, 5 times firing respectively, the chroma of yttria stabilized tetragonal zirconia polycrystal by adding rare-earth oxides are with high stability.

[Preparation and color analysis of tooth-like yttria stabilized tetragonal zirconia polycrystal].

PURPOSE: To develop six kinds tooth-like yttria stabilized tetragonal zirconia polycrystal (Y-TZP) ceramic blocks. METHODS: Six kinds (S1, S2, S3, S4, S5,S6) of tooth-like yttria stabilized tetragonal zirconia polycrystal (Y-TZP) were made by introducing internal colorating technology, and the color gauged with shade-eye chromatometry instrument was compared between Vita classical shade selection and the 6 kinds of tooth-like ceramic blocks. RESULTS: The color of 6 kinds of tooth-like TZP was presented in CIELab system. The value of L* was from 68.8-80.37, a* was from -1.0-0.9, and b* was from 12.2-17.93, which was covered by Vita classical shade selecting and Chinese tooth color parameter. CONCLUSIONS: Rare earth and transition element as colorants can endow TZP with tooth-like color with different proportions. It is possible to develop tooth-like Y-TZP by adding minority rare earth oxides (Pr6O11, CeO2, Er2O3, MnO2). Supported by Key Project of Biomedicine Sponsored by Science and Technology Commission of Shanghai Municipality (Grant No.09411954600), Research Fund of Science and Technology Commission of Shanghai Municipality (Grant No.08DZ2271100) and Research Fund of Excellent Young Teachers of Shanghai Municipality (Grant No.JDY090460).