Polyurethane coated urea slow/controlled release fertilizer was prepared based on urea granules, isocyanate, polyols and paraffin. Isocyanate reacted with polyols to synthesize the polyurethane skin layer on urea gran...Polyurethane coated urea slow/controlled release fertilizer was prepared based on urea granules, isocyanate, polyols and paraffin. Isocyanate reacted with polyols to synthesize the polyurethane skin layer on urea granules surface. Paraffin serves as a lubricant during syntheses of polyurethane skin layers. The structure and nutrient release characteristics of the polyurethane skin layers were investigated by FTIR, SEM and TG. Urea nitrogen slow-release behavior of the polyurethane coated urea was tested. The experimental results indicated that compact and dense polyurethane skin layers with a thickness of 10-15 lam were formed on urea surface, the urea nitrogen slow-release time can reach 40-50 days. Paraffin proves to play a key role in inhibiting water to penetrate into urea, but excessive addition would decrease the polyurethane crosslinking density.展开更多
The microstructure of a Cu-Zn alloy treated under different high pressures was investigated by means of metallographic, scanning electron microscope （SEM）, energy dispersive spectrometer （EDS）, and X-ray diffracti...The microstructure of a Cu-Zn alloy treated under different high pressures was investigated by means of metallographic, scanning electron microscope （SEM）, energy dispersive spectrometer （EDS）, and X-ray diffraction （XRD）, and the hardness of the Cu-Zn alloy was also measured. The results show that the ct phase with a smaller grain size, different shapes, and random distribution appears in the Cu-Zn alloy during the solid-state phase transformation generation in the temperature range of 25-750℃ and the pressure range of 0-6 GPa. The amount of residual α phase in the microstructure decreases and then increases with increasing pressure. Under a high pressure of 3 GPa, the least volume fraction of residual a phase was obtained, and under a high pressure of 6 GPa, the changes of the microstructure of the Cu-Zn alloy were not obvious. In addition, high pressure can increase the hardness of the Cu-Zn alloy, but it cannot generate any new phase.展开更多
A perovskite-type oxide, La0.8Sr0.2MnO3, was synthesized by the organic solvent sol-gel method. The desired metal cations were chelated in a solution by using citric acid as the chelating agent and absolute ethanol as...A perovskite-type oxide, La0.8Sr0.2MnO3, was synthesized by the organic solvent sol-gel method. The desired metal cations were chelated in a solution by using citric acid as the chelating agent and absolute ethanol as the solvent. The thermal decomposition of the metal carboxylate precursor gels was studied by thermogravimetric/differential thermal analyzer （TG/DTA） and the products derived from calcining the gels were characterized by X-ray diffraction （XRD） and transmission electronic microscope （TEM）. The polarization curves were acquired on an electrochemical workstation （LK98） and the discharge curves were acquired on a testing instrument of batteries （DC-5）, with a constant current discharge, less than 120 mA/cm^2. The results revealed that the nanometer perovskite-type powder with lesser particle size could be achieved with an organic solvent and had a better catalytic activity.展开更多
In the edge detection of Remote Sensing (RS) image, the useful detail losing and the spurious edge often appear. To solve the problem, the authors uses the dyadic wavelet to detect the edge of surface features by comb...In the edge detection of Remote Sensing (RS) image, the useful detail losing and the spurious edge often appear. To solve the problem, the authors uses the dyadic wavelet to detect the edge of surface features by combining the edge detecting with the multi-resolution analyzing of the wavelet transform. Via the dyadic wavelet decomposing, the RS image of a certain appropriate scale is obtained, and the edge data of the plane and the upright directions are respectively figured out, then the gradient vector module of the surface features is worked out. By tracing them, the authors get the edge data of the object, therefore build the RS image which obtains the checked edge. This method can depress the effect of noise and examine exactly the edge data of the object by rule and line. With an experiment of an RS image which obtains an airport, the authors certificate the feasibility of the application of dyadic wavelet in the object edge detection.展开更多
We have used a unique process to develop the first successful anion rubber modified asphalt mixture.Rubber and asphalt are used in equal proportions in the mix.Compared with conventional asphalt,the anion rubber modif...We have used a unique process to develop the first successful anion rubber modified asphalt mixture.Rubber and asphalt are used in equal proportions in the mix.Compared with conventional asphalt,the anion rubber modified asphalt show better pavement performance,and fully met the relevant specifications.The dynamic stability and failure strain indicators are better than those of SBS modified asphalt.Compared with traditional rubber modified asphalt,the amount of waste tires incorporated into this new rubber modified asphalt is much greater;the new asphalt also improved the air quality near the road,thus providing great economic and social benefits.展开更多
基金the National Key Technology R&D Program of the 11th Five-Year Period (No.2006BAD10B08)
文摘Polyurethane coated urea slow/controlled release fertilizer was prepared based on urea granules, isocyanate, polyols and paraffin. Isocyanate reacted with polyols to synthesize the polyurethane skin layer on urea granules surface. Paraffin serves as a lubricant during syntheses of polyurethane skin layers. The structure and nutrient release characteristics of the polyurethane skin layers were investigated by FTIR, SEM and TG. Urea nitrogen slow-release behavior of the polyurethane coated urea was tested. The experimental results indicated that compact and dense polyurethane skin layers with a thickness of 10-15 lam were formed on urea surface, the urea nitrogen slow-release time can reach 40-50 days. Paraffin proves to play a key role in inhibiting water to penetrate into urea, but excessive addition would decrease the polyurethane crosslinking density.
文摘The microstructure of a Cu-Zn alloy treated under different high pressures was investigated by means of metallographic, scanning electron microscope （SEM）, energy dispersive spectrometer （EDS）, and X-ray diffraction （XRD）, and the hardness of the Cu-Zn alloy was also measured. The results show that the ct phase with a smaller grain size, different shapes, and random distribution appears in the Cu-Zn alloy during the solid-state phase transformation generation in the temperature range of 25-750℃ and the pressure range of 0-6 GPa. The amount of residual α phase in the microstructure decreases and then increases with increasing pressure. Under a high pressure of 3 GPa, the least volume fraction of residual a phase was obtained, and under a high pressure of 6 GPa, the changes of the microstructure of the Cu-Zn alloy were not obvious. In addition, high pressure can increase the hardness of the Cu-Zn alloy, but it cannot generate any new phase.
文摘A perovskite-type oxide, La0.8Sr0.2MnO3, was synthesized by the organic solvent sol-gel method. The desired metal cations were chelated in a solution by using citric acid as the chelating agent and absolute ethanol as the solvent. The thermal decomposition of the metal carboxylate precursor gels was studied by thermogravimetric/differential thermal analyzer （TG/DTA） and the products derived from calcining the gels were characterized by X-ray diffraction （XRD） and transmission electronic microscope （TEM）. The polarization curves were acquired on an electrochemical workstation （LK98） and the discharge curves were acquired on a testing instrument of batteries （DC-5）, with a constant current discharge, less than 120 mA/cm^2. The results revealed that the nanometer perovskite-type powder with lesser particle size could be achieved with an organic solvent and had a better catalytic activity.
基金Supported by the National Natural Science Foundation of China (No.40071061).
文摘In the edge detection of Remote Sensing (RS) image, the useful detail losing and the spurious edge often appear. To solve the problem, the authors uses the dyadic wavelet to detect the edge of surface features by combining the edge detecting with the multi-resolution analyzing of the wavelet transform. Via the dyadic wavelet decomposing, the RS image of a certain appropriate scale is obtained, and the edge data of the plane and the upright directions are respectively figured out, then the gradient vector module of the surface features is worked out. By tracing them, the authors get the edge data of the object, therefore build the RS image which obtains the checked edge. This method can depress the effect of noise and examine exactly the edge data of the object by rule and line. With an experiment of an RS image which obtains an airport, the authors certificate the feasibility of the application of dyadic wavelet in the object edge detection.
基金supported by the National"Eleventh Five-Year"Technology Support Program Foundation(2006BAD10B08)the Natural Science Foundation of Hebei Province(E2009000448)
文摘We have used a unique process to develop the first successful anion rubber modified asphalt mixture.Rubber and asphalt are used in equal proportions in the mix.Compared with conventional asphalt,the anion rubber modified asphalt show better pavement performance,and fully met the relevant specifications.The dynamic stability and failure strain indicators are better than those of SBS modified asphalt.Compared with traditional rubber modified asphalt,the amount of waste tires incorporated into this new rubber modified asphalt is much greater;the new asphalt also improved the air quality near the road,thus providing great economic and social benefits.
