Sb substituted Sm 2Fe 17-x Sb x materials have been synthesized by using modified reduction diffusion process with superfine Fe metal powder as a starting material. This synthetic route is unique and particularly usef...Sb substituted Sm 2Fe 17-x Sb x materials have been synthesized by using modified reduction diffusion process with superfine Fe metal powder as a starting material. This synthetic route is unique and particularly useful for the intermetallic compounds containing high volatile component. The substitution of Sb to the Sm 2Fe 17 significantly enhances the magnetic interaction between Fe atoms, which in turn, increases the Curie temperature of the materials. In addition, the chemical stability of Sm 2Fe 17 can also be improved by Sb substitution.展开更多
In this papre,a new and microscale experimental method of determining ammonia content is reported for the first time.Boracic acid and mixed indicator are used as the solution to absorb ammonia.The indicator turns from...In this papre,a new and microscale experimental method of determining ammonia content is reported for the first time.Boracic acid and mixed indicator are used as the solution to absorb ammonia.The indicator turns from bright green to violet red as soon as the solution is basic and then the collecting ammonia is titrated with standard chlorhydric acid.The results of the experiment show that this method is opearated readily with simple apparatus,less reagents and shorter reaction time.The merits of using mixed indicator lie in the high sensitivity,clear reaction phenomena and visible effect.The results obtained with this method agree with the theoretical value.展开更多
The powder of xwt%SiO2-WO3 was prepared by chemical precipitation.The microstructure was characterized through XRD and TEM.The effects of SiO2 content and sensors operating temperature on the sensitivity were investig...The powder of xwt%SiO2-WO3 was prepared by chemical precipitation.The microstructure was characterized through XRD and TEM.The effects of SiO2 content and sensors operating temperature on the sensitivity were investigated.The results show that the sensitivity to H2S rises when SiO2 added.The sensor has high sensitivity and good selectivity to H2S when x=5 and the optimum working temperature is 180℃.展开更多
文摘Sb substituted Sm 2Fe 17-x Sb x materials have been synthesized by using modified reduction diffusion process with superfine Fe metal powder as a starting material. This synthetic route is unique and particularly useful for the intermetallic compounds containing high volatile component. The substitution of Sb to the Sm 2Fe 17 significantly enhances the magnetic interaction between Fe atoms, which in turn, increases the Curie temperature of the materials. In addition, the chemical stability of Sm 2Fe 17 can also be improved by Sb substitution.
文摘In this papre,a new and microscale experimental method of determining ammonia content is reported for the first time.Boracic acid and mixed indicator are used as the solution to absorb ammonia.The indicator turns from bright green to violet red as soon as the solution is basic and then the collecting ammonia is titrated with standard chlorhydric acid.The results of the experiment show that this method is opearated readily with simple apparatus,less reagents and shorter reaction time.The merits of using mixed indicator lie in the high sensitivity,clear reaction phenomena and visible effect.The results obtained with this method agree with the theoretical value.
文摘The powder of xwt%SiO2-WO3 was prepared by chemical precipitation.The microstructure was characterized through XRD and TEM.The effects of SiO2 content and sensors operating temperature on the sensitivity were investigated.The results show that the sensitivity to H2S rises when SiO2 added.The sensor has high sensitivity and good selectivity to H2S when x=5 and the optimum working temperature is 180℃.
