The membrane microstructures and the mechanism of two coated ureas formed through solid- liquid reaction were observed by scanning electron microscope and infrared spectra, the relation of the structural characteris...The membrane microstructures and the mechanism of two coated ureas formed through solid- liquid reaction were observed by scanning electron microscope and infrared spectra, the relation of the structural characteristics with the nitrogen release feature was also discussed by combining with nitrogen dissolution in water. The results showed that the membranes were made of solid particles tightly connected to each other and were piled up layer by layer through liquid glue. Porosity and aperture of membrane were determined by compactness of piled layers and the particles in a single layer and also related to the characteristics of coating materials. Research of the infrared spectra of membrane, made of a solid powder and a liquid glue, proved that O-H on the solid surface was bonded with the double bond of the liquid glue, thus forming membrane and keeping it stable. It was found that the two coated ureas showed obvious differences in nitrogen releasing due to their membrane structures, the porosity and aperture of membrane were the critical factors for nitrogen releasing.展开更多
The technological condition for the preparation of BaTiO 3 ceramics doped with Nd ￡2O￡3 by Sol￡-Gel was deter￡-mined through orthogonal experimen t￡(r)WhennBa ￡¨Ac ￡(c) ￡2??nTi ￡¨OC ￡′H￡1￡(c)￡...The technological condition for the preparation of BaTiO 3 ceramics doped with Nd ￡2O￡3 by Sol￡-Gel was deter￡-mined through orthogonal experimen t￡(r)WhennBa ￡¨Ac ￡(c) ￡2??nTi ￡¨OC ￡′H￡1￡(c)￡′??n Nd ￡2O￡3??nCH￡3￡¨CH￡2￡(c)2CH 2OH∶n H2 O￡1/2￡±￡(r)￡°￡°??￡±￡(r)￡°￡°??￡°￡(r)￡°￡°￡3??￡*￡(r)￡3￡°??￡3￡*￡(r)￡°￡′￡?pH ￡1/2￡3￡(r)￡μ￡?T￡1/225℃,the light-yellow-transparen t-stable solution and thorough tran sparent gel was generat￡-ed￡?the transforming time of solutio n to gel was ￡2￡μh￡(r)The crystal structur e and particle size of BaTiO3 ceramics doped with Nd 2O3 were studied by SEM and X-ray respectively￡?the type of the crystal was tetragonal￡?the particle size was about ￡2￡′￡(r)7nm￡(r)The dielectric constant ￡¨|?￡(c)and dielectric loss￡¨tan|?￡(c)of BaTiO3 ceramics doped with Nd 2O3 were determined between 10 4 ?10 6 Hz,and the results showed that the di electric constant was increased obviously,the dielectric loss was d ecreased clear and the resistivity(ρ V ￡(c)was also decreased noticeably￡(r)展开更多
基金The project was supported by the National 863 Program(2001AA2 46023)the Guangdong Controlled-Release Fertilizer Project(2KB 05601N)the Guangzhou Controlled-Re-lease Fertilizer Project(2001Z02402),P.R.China.
文摘The membrane microstructures and the mechanism of two coated ureas formed through solid- liquid reaction were observed by scanning electron microscope and infrared spectra, the relation of the structural characteristics with the nitrogen release feature was also discussed by combining with nitrogen dissolution in water. The results showed that the membranes were made of solid particles tightly connected to each other and were piled up layer by layer through liquid glue. Porosity and aperture of membrane were determined by compactness of piled layers and the particles in a single layer and also related to the characteristics of coating materials. Research of the infrared spectra of membrane, made of a solid powder and a liquid glue, proved that O-H on the solid surface was bonded with the double bond of the liquid glue, thus forming membrane and keeping it stable. It was found that the two coated ureas showed obvious differences in nitrogen releasing due to their membrane structures, the porosity and aperture of membrane were the critical factors for nitrogen releasing.
文摘The technological condition for the preparation of BaTiO 3 ceramics doped with Nd ￡2O￡3 by Sol￡-Gel was deter￡-mined through orthogonal experimen t￡(r)WhennBa ￡¨Ac ￡(c) ￡2??nTi ￡¨OC ￡′H￡1￡(c)￡′??n Nd ￡2O￡3??nCH￡3￡¨CH￡2￡(c)2CH 2OH∶n H2 O￡1/2￡±￡(r)￡°￡°??￡±￡(r)￡°￡°??￡°￡(r)￡°￡°￡3??￡*￡(r)￡3￡°??￡3￡*￡(r)￡°￡′￡?pH ￡1/2￡3￡(r)￡μ￡?T￡1/225℃,the light-yellow-transparen t-stable solution and thorough tran sparent gel was generat￡-ed￡?the transforming time of solutio n to gel was ￡2￡μh￡(r)The crystal structur e and particle size of BaTiO3 ceramics doped with Nd 2O3 were studied by SEM and X-ray respectively￡?the type of the crystal was tetragonal￡?the particle size was about ￡2￡′￡(r)7nm￡(r)The dielectric constant ￡¨|?￡(c)and dielectric loss￡¨tan|?￡(c)of BaTiO3 ceramics doped with Nd 2O3 were determined between 10 4 ?10 6 Hz,and the results showed that the di electric constant was increased obviously,the dielectric loss was d ecreased clear and the resistivity(ρ V ￡(c)was also decreased noticeably￡(r)
