Nanoscale powder of SiO2/Al2O3/TiO2 composite was prepared by sol-gel method. Microstructure and morphology of the obtained samples were characterized by infrared （IR）, X-ray diffraction （XRD） analysis and transmi...Nanoscale powder of SiO2/Al2O3/TiO2 composite was prepared by sol-gel method. Microstructure and morphology of the obtained samples were characterized by infrared （IR）, X-ray diffraction （XRD） analysis and transmission electron microscopy （TEM）. It is proved that infrared absorbing peaks of the samples are in waveband range of 1300-400 cm^-1, and the peak shape changes with their component. Mechanism of the infrared peak＇s positions and shapes which changes with the size and morphology of the prepared nano-particles has been tentatively discussed.展开更多
The ecological characteristics and fiber structure of the colored cotton were introduced briefly. The color changing mechanisms of the pigments extracted from colored cottons and some plants were discussed with the re...The ecological characteristics and fiber structure of the colored cotton were introduced briefly. The color changing mechanisms of the pigments extracted from colored cottons and some plants were discussed with the results of different experiments, which could offer an academic reference for the color fixations of the colored cotton textile produces and promote the development of the natural colored cotton industry.展开更多
Al2O3/TiOe/FeeO3/Yb2O3 composite powder was synthesized via the sol-gel method. The structure, morphology, and ra- dar-absorption properties of the composite powder were characterized by transmission electron microsco...Al2O3/TiOe/FeeO3/Yb2O3 composite powder was synthesized via the sol-gel method. The structure, morphology, and ra- dar-absorption properties of the composite powder were characterized by transmission electron microscopy, X-ray diffraction analysis and RF impedance analysis. The results show that two types of particles exist in the composite powder. One is irregular flakes （100-200 rim） and the other is spherical A1203 particles （smaller than 80 rim）. Electromagnetic wave attenuation is mostly achieved by dielectric loss. The maximum value of the dissipation factor reaches 0.76 （at 15.68 GHz） in the frequency range of 2-18 GHz. The electromagnetic absorption of waves covers 2-18 GHz with the matching thicknesses of 1.5-4.5 mm. The absorption peak shifts to the lower-frequency area with increas- ing matching thickness. The effective absorption hand covers the frequency range of 2.16-9.76 GHz, and the maximum absorption peak reaches -20.18 dB with a matching thickness of 3.5 mm at a frequency of 3.52 GHz.展开更多
In order to improve the absorbency of color cotton products, alkali and pectase scouring processes under different conditions were tested, by comparing the actual results of two different scouring processes. It was co...In order to improve the absorbency of color cotton products, alkali and pectase scouring processes under different conditions were tested, by comparing the actual results of two different scouring processes. It was considered that the pectase scouring process more suits color cotton products.展开更多
MnZn-doped W-type barium cobalt ferrite powder composites of Ba(MnZn)xCo2(1-x)Fe16O27 (x = 0.1, 0.2, 0.3, 0.4, and 0.5) were prepared in a sol-gel process. The microwave absorbing properties of the composites in the r...MnZn-doped W-type barium cobalt ferrite powder composites of Ba(MnZn)xCo2(1-x)Fe16O27 (x = 0.1, 0.2, 0.3, 0.4, and 0.5) were prepared in a sol-gel process. The microwave absorbing properties of the composites in the range of 2 - 18 GHz and their electromagnetic loss mechanisms were studied. The results demonstrated that the synthesized Ba(MnZn)xCo2(1-x)Fe16O27 samples possess a W-type phase of the crystal structure with a hexagonal flaky shape in micro-morphology, and the samples exhibited a soft magnetic trait that enables improving their microwave absorption properties through suitable MnZn doping. For Ba(MnZn)0.4Co1.2Fe16O27 with a thickness of 2.8 mm, the reflection loss peak was -40.7 dB at a frequency of 7.3 GHz, with a bandwidth of 6.6 GHz at a loss of less than -10 dB. The microwave absorption primarily resulted from magnetic losses caused by magnetization relaxation, domain wall resonance, and natural resonance.展开更多
基金the Science Foundation of Yunnan Province under grant No.2001E0003Z.
文摘Nanoscale powder of SiO2/Al2O3/TiO2 composite was prepared by sol-gel method. Microstructure and morphology of the obtained samples were characterized by infrared （IR）, X-ray diffraction （XRD） analysis and transmission electron microscopy （TEM）. It is proved that infrared absorbing peaks of the samples are in waveband range of 1300-400 cm^-1, and the peak shape changes with their component. Mechanism of the infrared peak＇s positions and shapes which changes with the size and morphology of the prepared nano-particles has been tentatively discussed.
文摘The ecological characteristics and fiber structure of the colored cotton were introduced briefly. The color changing mechanisms of the pigments extracted from colored cottons and some plants were discussed with the results of different experiments, which could offer an academic reference for the color fixations of the colored cotton textile produces and promote the development of the natural colored cotton industry.
基金financially supported by the National Natural Science Foundation of China (No.51471023)the Major State Basic Research Development Program of China (No.2014GB120000)
文摘Al2O3/TiOe/FeeO3/Yb2O3 composite powder was synthesized via the sol-gel method. The structure, morphology, and ra- dar-absorption properties of the composite powder were characterized by transmission electron microscopy, X-ray diffraction analysis and RF impedance analysis. The results show that two types of particles exist in the composite powder. One is irregular flakes （100-200 rim） and the other is spherical A1203 particles （smaller than 80 rim）. Electromagnetic wave attenuation is mostly achieved by dielectric loss. The maximum value of the dissipation factor reaches 0.76 （at 15.68 GHz） in the frequency range of 2-18 GHz. The electromagnetic absorption of waves covers 2-18 GHz with the matching thicknesses of 1.5-4.5 mm. The absorption peak shifts to the lower-frequency area with increas- ing matching thickness. The effective absorption hand covers the frequency range of 2.16-9.76 GHz, and the maximum absorption peak reaches -20.18 dB with a matching thickness of 3.5 mm at a frequency of 3.52 GHz.
文摘In order to improve the absorbency of color cotton products, alkali and pectase scouring processes under different conditions were tested, by comparing the actual results of two different scouring processes. It was considered that the pectase scouring process more suits color cotton products.
文摘MnZn-doped W-type barium cobalt ferrite powder composites of Ba(MnZn)xCo2(1-x)Fe16O27 (x = 0.1, 0.2, 0.3, 0.4, and 0.5) were prepared in a sol-gel process. The microwave absorbing properties of the composites in the range of 2 - 18 GHz and their electromagnetic loss mechanisms were studied. The results demonstrated that the synthesized Ba(MnZn)xCo2(1-x)Fe16O27 samples possess a W-type phase of the crystal structure with a hexagonal flaky shape in micro-morphology, and the samples exhibited a soft magnetic trait that enables improving their microwave absorption properties through suitable MnZn doping. For Ba(MnZn)0.4Co1.2Fe16O27 with a thickness of 2.8 mm, the reflection loss peak was -40.7 dB at a frequency of 7.3 GHz, with a bandwidth of 6.6 GHz at a loss of less than -10 dB. The microwave absorption primarily resulted from magnetic losses caused by magnetization relaxation, domain wall resonance, and natural resonance.
