In Malaysia, airborne hyperspectral remote sensing is a relatively new technique used for research and commercial value in forest inventory and mapping. An advantage of airborne remote sensing, compared to satellite r...In Malaysia, airborne hyperspectral remote sensing is a relatively new technique used for research and commercial value in forest inventory and mapping. An advantage of airborne remote sensing, compared to satellite remote sensing, is its capability of offering a very high spatial resolution images. Thus, UPM-TropAIR AISA＇s airborne hyperspectral imagery that has been used in this study provides great quantity, better quality and also lower cost in identifying, quantifying and mapping of the Malaysian tropical timber forest resources. For the first stage in this study, the development of spectral library is deemed required in order for the Spectral Angle Mapper （SAM） classification be used to separate and map individual tree species in a tropical mixed mountain forest of Gunong Stong Forest Reserve. Pre-processing, enhancement and interpretation of image were conducted using ENVI Version 4.0 software. Results indicated that a total of eight commercial timber tree species was identified and mapped in a study plot of 5 ha using the TropAIR airborne hyperspectral imager with the aid of ground truthings.展开更多
It is of considerable importance to investigate the influence of weathering on the degradation processes of heat-treated wood. Kiln-dried （untreated）jack pine （Pinus banksiana） and jack pine heat-treated at three ...It is of considerable importance to investigate the influence of weathering on the degradation processes of heat-treated wood. Kiln-dried （untreated）jack pine （Pinus banksiana） and jack pine heat-treated at three different temperatures （190 ℃, 200 ℃, and 210 ℃） were exposed to artificial weathering for different periods in order to understand the degradation processes due to weathering. Before and after exposure, their color and wettability by water were determined. Structural changes and chemical modifications at exposed surfaces were also investigated using SEM （scanning electron spectroscopy）, FTIR （Fourier transforms infrared spectroscopy）, and XPS （X-ray photoelectron spectroscopy）. The results revealed that the photo-degradation of lignin and the presence of extractives play important roles in color change and wetting behavior of heat-treated wood surfaces during weathering. The structural changes also influence the wettability. The effects of weathering for woods heat-treated under different conditions were similar, but different from those for untreated wood.展开更多
Certain activator was expected to be developed to improve the free radical intermediates relative intensity, and thus to enhance the adhesion between wood fibers when fiberboard was made by laccase treated wood fibers...Certain activator was expected to be developed to improve the free radical intermediates relative intensity, and thus to enhance the adhesion between wood fibers when fiberboard was made by laccase treated wood fibers. Reactive oxygen species (ROS) was detected in laccase-catalyzed oxidation of wood powder using ESR spin trapping technique. The effects of five metal ions (Cu2+, K+, Fe2+, Mg2+, Fe3+) and EDTA on ROS relative strengths were investigated under the condition of pH 5.6 by electron spin resonance spectrometry. The result shows that Cu2+ slightly activates the free radical reaction, and Fe2+ ion has a significant inhibitive effect on the ROS relative strength in the suspension liquid. There is a marked inhibition of the ROS relative intensity when 0.5 mmol/L EDTA is used. The metal ions that enhance laccase activity may be utilized to increase physical properties of fiberboard made by laccase oxidized wood fibers.展开更多
文摘In Malaysia, airborne hyperspectral remote sensing is a relatively new technique used for research and commercial value in forest inventory and mapping. An advantage of airborne remote sensing, compared to satellite remote sensing, is its capability of offering a very high spatial resolution images. Thus, UPM-TropAIR AISA＇s airborne hyperspectral imagery that has been used in this study provides great quantity, better quality and also lower cost in identifying, quantifying and mapping of the Malaysian tropical timber forest resources. For the first stage in this study, the development of spectral library is deemed required in order for the Spectral Angle Mapper （SAM） classification be used to separate and map individual tree species in a tropical mixed mountain forest of Gunong Stong Forest Reserve. Pre-processing, enhancement and interpretation of image were conducted using ENVI Version 4.0 software. Results indicated that a total of eight commercial timber tree species was identified and mapped in a study plot of 5 ha using the TropAIR airborne hyperspectral imager with the aid of ground truthings.
文摘It is of considerable importance to investigate the influence of weathering on the degradation processes of heat-treated wood. Kiln-dried （untreated）jack pine （Pinus banksiana） and jack pine heat-treated at three different temperatures （190 ℃, 200 ℃, and 210 ℃） were exposed to artificial weathering for different periods in order to understand the degradation processes due to weathering. Before and after exposure, their color and wettability by water were determined. Structural changes and chemical modifications at exposed surfaces were also investigated using SEM （scanning electron spectroscopy）, FTIR （Fourier transforms infrared spectroscopy）, and XPS （X-ray photoelectron spectroscopy）. The results revealed that the photo-degradation of lignin and the presence of extractives play important roles in color change and wetting behavior of heat-treated wood surfaces during weathering. The structural changes also influence the wettability. The effects of weathering for woods heat-treated under different conditions were similar, but different from those for untreated wood.
基金This work was supported by the National Natural Science Foundation of China (30471352).
文摘Certain activator was expected to be developed to improve the free radical intermediates relative intensity, and thus to enhance the adhesion between wood fibers when fiberboard was made by laccase treated wood fibers. Reactive oxygen species (ROS) was detected in laccase-catalyzed oxidation of wood powder using ESR spin trapping technique. The effects of five metal ions (Cu2+, K+, Fe2+, Mg2+, Fe3+) and EDTA on ROS relative strengths were investigated under the condition of pH 5.6 by electron spin resonance spectrometry. The result shows that Cu2+ slightly activates the free radical reaction, and Fe2+ ion has a significant inhibitive effect on the ROS relative strength in the suspension liquid. There is a marked inhibition of the ROS relative intensity when 0.5 mmol/L EDTA is used. The metal ions that enhance laccase activity may be utilized to increase physical properties of fiberboard made by laccase oxidized wood fibers.
