Earth sensors are widely used in spacecraft for attitude determination. They need to have a very large field of view(FOV)( > 120°) and relatively low accuracy while being used in the aircrafts around orbit. A ...Earth sensors are widely used in spacecraft for attitude determination. They need to have a very large field of view(FOV)( > 120°) and relatively low accuracy while being used in the aircrafts around orbit. A triple-FOV infrared earth sensor is proposed in this paper. It uses three pieces of standard infrared detectors with a wavelength range of 14;16μm,to sense the horizontal circle by detecting the infrared light emitted from the earth. From which,the geocentric vector can be obtained. A mathematic model is established and a validation model is set up to provide input parameters for the mathematic model. The simulation results of the two models show that the output of the mathematic model coincides with the known parameters. Based on the above analysis,a prototype has been built and tested. The test results show that the angle measurement error is about 0. 002° and hence such a triple-FOV earth sensor is capable to provide high-precision position information for autonomous navigation.展开更多
Infrared Earth sensors are widely used in attitude-determination and control systems of satellites.The main deficiency of static infrared Earth sensors is the requirement of a small field of view(FOV).A typical FOV fo...Infrared Earth sensors are widely used in attitude-determination and control systems of satellites.The main deficiency of static infrared Earth sensors is the requirement of a small field of view(FOV).A typical FOV for a static infrared Earth sensor is about 20°to 30°,which may not be sufficient for low-Earth-orbiting microsatellites.A novel compact infrared Earth sensor with an FOV of nearly 180°is developed here.The Earth sensor comprises a panoramic annular lens(PAL)and an off-the-shelf camera with an uncooled complementary-metaloxide-semiconductor(CMOS)infrared sensor.PAL is used to augment FOV so as to obtain a complete infrared image of the Earth from low-Earth-orbit.An algorithm is developed to compensate for the distortion caused by PAL and to calculate the vector of the Earth.The new infrared Earth sensor is compact with low power consumption and high precision.Simulated images and on-orbit infrared images obtained via the micro-satellite ZDPS-2 are used to assess the performance of the new infrared Earth sensor.Experiments show that the accuracy of the Earth sensor is about 0.032°.展开更多
Throught fusion of the mechanism modeling and the neural networks modeling,a compo- nent content soft-sensor,which is composed of the equilibrium calculation model for multi-component rare earth extraction and the err...Throught fusion of the mechanism modeling and the neural networks modeling,a compo- nent content soft-sensor,which is composed of the equilibrium calculation model for multi-component rare earth extraction and the error compensation model of fuzzy system,is proposed to solve the prob- lem that the component content in countercurrent rare-earth extraction process is hardly measured on-line.An industry experiment in the extraction Y process by HAB using this hybrid soft-sensor proves its effectiveness.展开更多
This paper addresses the problem of sensor search scheduling in the complicated space environment faced by the low-earth orbit constellation.Several search scheduling methods based on the commonly used information gai...This paper addresses the problem of sensor search scheduling in the complicated space environment faced by the low-earth orbit constellation.Several search scheduling methods based on the commonly used information gain are compared via simulations first.Then a novel search scheduling method in the scenarios of uncertainty observation is proposed based on the global Shannon information gain and beta density based uncertainty model.Simulation results indicate that the beta density model serves a good option for solving the problem of target acquisition in the complicated space environments.展开更多
The rare earth doped TiO（2） was prepared and characterized with Nd,Ho and Y as the doping agents,which have obvious absorption in visible light area.The particle size of the glomeration was about 200-400 nm.TiO2 sen...The rare earth doped TiO（2） was prepared and characterized with Nd,Ho and Y as the doping agents,which have obvious absorption in visible light area.The particle size of the glomeration was about 200-400 nm.TiO2 sensor performed a significant change in resistance when exposed to methanol vapor.By comparison,the Nd,Ho and Yb doped TiO2 sensors exhibited a response of 2.22,4.05 and 3.78,and lowered response and recovery times of 91,56 and 67 s,respectively.The Ho doped TiO2 showed the best methanolsensing properties,which exhibited high selectivity and response to methanol compared with the other tested vapors.In concentration of 0-10 ppm,the sensor exhibited excellent stability for detecting methanol at various concentrations.展开更多
The equilibrium model for multicomponent rare earth extraction is developed using neural networks, which combined with the material balance model could give online prediction of component content in countercurrent rar...The equilibrium model for multicomponent rare earth extraction is developed using neural networks, which combined with the material balance model could give online prediction of component content in countercurrent rare earth (extraction) production. Simulation experiments with industrial operation data prove the effectiveness of the hybrid soft-(sensor).展开更多
Nanocrystalline indium oxide powders were prepared by microemulsion and then Y2O3 and Nd2O3 doped In2O3 were synthesized separately by impregnation and chemical co-deposition. The structure and morphology were charact...Nanocrystalline indium oxide powders were prepared by microemulsion and then Y2O3 and Nd2O3 doped In2O3 were synthesized separately by impregnation and chemical co-deposition. The structure and morphology were characterized by XRD and TEM, respectively. Gas sensing properties were tested at static state. The results show that homogeneous indium oxide nanopowder with main grain size of 20 nm can be obtained from microemulsion after sintered at 600 ℃ for 1 h. Pure indium oxide gas sensor has higher sensitivity to gasoline than that to ethanol, HCHO, C6H6, NH3, C4H10, but the selectivity is not as well as sensitivity.展开更多
In this work wavelength sensitivity in mechanically induced long period fiber gratings (MLPFG) is analyzed. This analysis is first carried out both in standard single-mode fiber SMF-28 and in Er-doped fibers. The mech...In this work wavelength sensitivity in mechanically induced long period fiber gratings (MLPFG) is analyzed. This analysis is first carried out both in standard single-mode fiber SMF-28 and in Er-doped fibers. The mechanical analysis for both types of fibers under different torsion conditions is presented. In order to apply the torsion one of the fiber ends is fixed while torsion is applied on the other end. A MLPFG whose period is 503 μm is used to press the fiber after torsion is applied. This allows for micro curvatures to be formed on the fiber, which in turn generates a periodical index perturbation on it. Here, it was noted that the sensitive wavelength shift of the rejection bands is bigger for Er-doped fibers. For a torsion of 6 turns applied to 10 cm of doped fiber the wavelength peaks can be moved up to 25 nm, which is longer to what was detected on standard fibers. Therefore, by using Er-doped fibers to monitor torsion on structures will give more sensitive and accurate results than using standard fibers. These results can be employed for sensing applications, especially for small to medium size structures, which can be mechanical, civil or aeronautics.展开更多
Photoluminescent hybrid materials containing carboxymethyl cellulose and lanthanide ions（Eu3＋, Tb3＋）were prepared by a facile method under ambient conditions. Lanthanide ions were covalently grafted to the cellulo...Photoluminescent hybrid materials containing carboxymethyl cellulose and lanthanide ions（Eu3＋, Tb3＋）were prepared by a facile method under ambient conditions. Lanthanide ions were covalently grafted to the cellulose framework through coordination with the carboxylic groups of the cellulose. Hybrid materials were fabricated as hydrogel and aerogel. As shown by SEM and pore parameters, aerogel materials which were obtained by supercritical CO2 drying show hierarchical porous structure. The photoluminescence spectrum of the hybrid materials shows the characteristic red emission of Eu3＋ ion and green emission of Tb3＋. Further luminescent investigations reveal that these hybrid materials can detect Fe3＋ with relative selectivity and high sensitivity, which suggests that the hybrid materials could be a promising luminescent probe for selectively sensing Fe3＋ ion.展开更多
The CO_2 sensing of PrFeO_3 and NdFeO_3 sensors were investigated. Experimental results show that the resistances for PrFeO_3 and NdFeO_3 in CO_2 gas are larger than those in air and the responses for PrFeO_3and NdFeO...The CO_2 sensing of PrFeO_3 and NdFeO_3 sensors were investigated. Experimental results show that the resistances for PrFeO_3 and NdFeO_3 in CO_2 gas are larger than those in air and the responses for PrFeO_3and NdFeO_3 sensors increase with an increase in room-temperature relative humidity. When exposed to1000 ppm CO_2, the response of PrFeO_3 thick film based on nano-powders annealed at 700℃can reach8.44 at 160℃for the background of wet air with 58%of room-temperature relative humidity (RH),which is much larger than the corresponding value (3.03) in wet air with 25%RH. The sensing response S of NdFeO_3 thick-film sensor based on nano-powders annealed at 600℃to 3000 ppm CO_2 at the operating temperature 200℃can reach 2.36 for the background of wet air with 72%RH, which is larger than the corresponding value (1.83) in the air with 25%RH. Compared with other CO_2 sensing materials, the PrFeO_3 sensor has larger response at lower operating temperature for CO_2 gas and may be used as a new CO_2 sensing material.展开更多
The PdC12 was mixed with nanocrystalline powders LaFeO3 and subsequently followed by an annealing of 800 ℃. PdO phase was formed and almost distributed uniformly on the surface of LaFeO3 nano-particles. With an incre...The PdC12 was mixed with nanocrystalline powders LaFeO3 and subsequently followed by an annealing of 800 ℃. PdO phase was formed and almost distributed uniformly on the surface of LaFeO3 nano-particles. With an increase of PdO amounts in composite powders, sensing sensitivity Rg/Ra to low concentration acetone or ethanol for Pd doped LaFeO3 sensors increased at first, underwent the maximum with 2 wt.% PdC12 dopant, and then doped again. Interestingly, appropriate Pd doping in LaFeO3 changed the selectivity behavior of gas sensing. LaFeO3 sensor showed good selectivity to ethanol, but 2 wt.% Pd doped LaFeO3 sensor showed good selectivity to acetone. The sensitivity for LaFeO3 at 200 ℃was 1.32 to 1 ppm ethanol, and 1.19 to 1 ppm acetone. Whereas the sensitivity for 2 wt.% Pd doped LaFeO3 at 200 ℃ was 1.53 to 1 ppm ethanol, and 1.9 to 1 ppm acetone. The 2 wt.% Pd doped LaFeO3 sensor at 200 ℃ showed very short response time （4 s） and recovery time （2 s） to 1 ppm acetone gas, respectively. Such results showed that 2 wt.% Pd doped LaFeO3 sensor is a new promising sensing candidate for detecting low concentration acetone.展开更多
The sol-gel method was used to prepare the nanocrystalline Gd_（1–x）Ca_xFeO_3 （x=0–0.4） powders. The XRD results showed that all the Gd_（1–x）Ca_xFeO_3 （x=0–0.4） compounds crystallized as perovskite phase wi...The sol-gel method was used to prepare the nanocrystalline Gd_（1–x）Ca_xFeO_3 （x=0–0.4） powders. The XRD results showed that all the Gd_（1–x）Ca_xFeO_3 （x=0–0.4） compounds crystallized as perovskite phase with orthorhombic structure. The doping of Ca in GdFeO_3 not only reduced the resistance, but also enhanced the response to methanol. The Gd_（0.9）Ca_（0.1）FeO_3 showed the best response to methanol among Gd_（1–x）Ca_xFeO_3 sensors. Besides, it showed good selectivity to methanol among methanol, ethanol, CO and formaldehyde gases. The responses at 260 oC for Gd_（0.9）Ca_（0.1）FeO_3-based sensor to 600 ppm methanol, ethanol and CO gases were 117.7, 72.7 and 31.9, respectively. Even at quite low gas concentrations, Gd_（0.9）Ca_（0.1）FeO_3-based sensor had an obvious response. At 260 °C, the response of 1.54 was obtained to be 45 ppm methanol. The experimental results showed that nanocrystalline Gd_（0.9）Ca_（0.1）FeO_3 based sensor can be used to detect methanol gas.展开更多
An investigation on the photophysical properties of the newly designed terbium imidazole-4,5-dicarboxylic acid complex encapsulated in the inert matrices (tetraethoxysilane, TEOS) was performed. The composite material...An investigation on the photophysical properties of the newly designed terbium imidazole-4,5-dicarboxylic acid complex encapsulated in the inert matrices (tetraethoxysilane, TEOS) was performed. The composite material was very stable and showed strong green emission in pure water. Interestingly, we discovered that the luminescence of hybrid material was selectively responsive to H2PO4-. 1H-NMR and fluorescence spectra supported that the receptor had strong affinity to dihydrogen phosphate. Meanwhile, the luminescence was quenched by Fe3+ when adding different metal ions such as Fe3+, Pd2+, Cd2+, Co2+ and Mn2+ concomitantly. Moreover, thin film was successfully pre-pared by the same materials and it also exhibited selective recognition behavior to the above two ions.展开更多
On the basis of the description of the rare-earth countercurrent extraction process, the on-line detecting method and equipments of rare-earth elements and the application in the process of the rare-earth countercurre...On the basis of the description of the rare-earth countercurrent extraction process, the on-line detecting method and equipments of rare-earth elements and the application in the process of the rare-earth countercurrent extraction are summarized. The procedure simulation of the computer, the automation control method and its current application are also mentioned in the process of rare-earth countercurrent extraction. The method of soft sensor is proposed. Optimal control method based on object-oriented rare-earth countercurrent extraction process and integrated automation system composed of process management system and process control system are presented, which are the developing direction of the automation of rare-earth countercurrent extraction process.展开更多
Yttrium-doped SnO2 powders were successfully synthesized by solution co-precipitation method and characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The sensitivity of sensors based on...Yttrium-doped SnO2 powders were successfully synthesized by solution co-precipitation method and characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The sensitivity of sensors based on Y-doped SnO2 and SnO2 nanocrystals were investigated comparatively. The results indicated that Y-doped SnO2 was with the result of enhancement of sensitivity and selectivity to ethanol and reduction of sensitivity to other gas components. The enhancements of selectivity and sensitivity could be contributed to for two reasons. The first is that rare metal yttrium has a high alkalescence and good catalysis, and the second is that the nanosized crystallite and large specific surface area of Y-doped SnO2 is advantageous for gas-diffusion control as well as an increase in active sites for gas detection.展开更多
基金financially supported by the National High Technology Research and Development Program of China(863 Program)(No.2012AA121503 and No.2012AA120603)the National Natural Science Foundation of China(No.61377012)the Tsinghua University Initiative Scientific Research Program(No.20131089242)。
文摘Earth sensors are widely used in spacecraft for attitude determination. They need to have a very large field of view(FOV)( > 120°) and relatively low accuracy while being used in the aircrafts around orbit. A triple-FOV infrared earth sensor is proposed in this paper. It uses three pieces of standard infrared detectors with a wavelength range of 14;16μm,to sense the horizontal circle by detecting the infrared light emitted from the earth. From which,the geocentric vector can be obtained. A mathematic model is established and a validation model is set up to provide input parameters for the mathematic model. The simulation results of the two models show that the output of the mathematic model coincides with the known parameters. Based on the above analysis,a prototype has been built and tested. The test results show that the angle measurement error is about 0. 002° and hence such a triple-FOV earth sensor is capable to provide high-precision position information for autonomous navigation.
基金Project supported by the National Science Fund for Distinguished Young Scholars,China(No.6152403)。
文摘Infrared Earth sensors are widely used in attitude-determination and control systems of satellites.The main deficiency of static infrared Earth sensors is the requirement of a small field of view(FOV).A typical FOV for a static infrared Earth sensor is about 20°to 30°,which may not be sufficient for low-Earth-orbiting microsatellites.A novel compact infrared Earth sensor with an FOV of nearly 180°is developed here.The Earth sensor comprises a panoramic annular lens(PAL)and an off-the-shelf camera with an uncooled complementary-metaloxide-semiconductor(CMOS)infrared sensor.PAL is used to augment FOV so as to obtain a complete infrared image of the Earth from low-Earth-orbit.An algorithm is developed to compensate for the distortion caused by PAL and to calculate the vector of the Earth.The new infrared Earth sensor is compact with low power consumption and high precision.Simulated images and on-orbit infrared images obtained via the micro-satellite ZDPS-2 are used to assess the performance of the new infrared Earth sensor.Experiments show that the accuracy of the Earth sensor is about 0.032°.
基金Supported by National Natural Science Foundation of P.R.China(50474020,60534010,60504006)
文摘Throught fusion of the mechanism modeling and the neural networks modeling,a compo- nent content soft-sensor,which is composed of the equilibrium calculation model for multi-component rare earth extraction and the error compensation model of fuzzy system,is proposed to solve the prob- lem that the component content in countercurrent rare-earth extraction process is hardly measured on-line.An industry experiment in the extraction Y process by HAB using this hybrid soft-sensor proves its effectiveness.
基金supported by the National Defense Pre-research Foundation (9140A21041110KG0148)
文摘This paper addresses the problem of sensor search scheduling in the complicated space environment faced by the low-earth orbit constellation.Several search scheduling methods based on the commonly used information gain are compared via simulations first.Then a novel search scheduling method in the scenarios of uncertainty observation is proposed based on the global Shannon information gain and beta density based uncertainty model.Simulation results indicate that the beta density model serves a good option for solving the problem of target acquisition in the complicated space environments.
基金Funded by National Natural Science Foundation of China(No.51672196)
文摘The rare earth doped TiO（2） was prepared and characterized with Nd,Ho and Y as the doping agents,which have obvious absorption in visible light area.The particle size of the glomeration was about 200-400 nm.TiO2 sensor performed a significant change in resistance when exposed to methanol vapor.By comparison,the Nd,Ho and Yb doped TiO2 sensors exhibited a response of 2.22,4.05 and 3.78,and lowered response and recovery times of 91,56 and 67 s,respectively.The Ho doped TiO2 showed the best methanolsensing properties,which exhibited high selectivity and response to methanol compared with the other tested vapors.In concentration of 0-10 ppm,the sensor exhibited excellent stability for detecting methanol at various concentrations.
基金ProjectsupportedbytheNationalTenthFive Year PlanofKeyTechnology (2 0 0 2BA3 15A)
文摘The equilibrium model for multicomponent rare earth extraction is developed using neural networks, which combined with the material balance model could give online prediction of component content in countercurrent rare earth (extraction) production. Simulation experiments with industrial operation data prove the effectiveness of the hybrid soft-(sensor).
文摘Nanocrystalline indium oxide powders were prepared by microemulsion and then Y2O3 and Nd2O3 doped In2O3 were synthesized separately by impregnation and chemical co-deposition. The structure and morphology were characterized by XRD and TEM, respectively. Gas sensing properties were tested at static state. The results show that homogeneous indium oxide nanopowder with main grain size of 20 nm can be obtained from microemulsion after sintered at 600 ℃ for 1 h. Pure indium oxide gas sensor has higher sensitivity to gasoline than that to ethanol, HCHO, C6H6, NH3, C4H10, but the selectivity is not as well as sensitivity.
文摘In this work wavelength sensitivity in mechanically induced long period fiber gratings (MLPFG) is analyzed. This analysis is first carried out both in standard single-mode fiber SMF-28 and in Er-doped fibers. The mechanical analysis for both types of fibers under different torsion conditions is presented. In order to apply the torsion one of the fiber ends is fixed while torsion is applied on the other end. A MLPFG whose period is 503 μm is used to press the fiber after torsion is applied. This allows for micro curvatures to be formed on the fiber, which in turn generates a periodical index perturbation on it. Here, it was noted that the sensitive wavelength shift of the rejection bands is bigger for Er-doped fibers. For a torsion of 6 turns applied to 10 cm of doped fiber the wavelength peaks can be moved up to 25 nm, which is longer to what was detected on standard fibers. Therefore, by using Er-doped fibers to monitor torsion on structures will give more sensitive and accurate results than using standard fibers. These results can be employed for sensing applications, especially for small to medium size structures, which can be mechanical, civil or aeronautics.
基金Project supported by the National Natural Science Foundation of China(21161023,21661034)
文摘Photoluminescent hybrid materials containing carboxymethyl cellulose and lanthanide ions（Eu3＋, Tb3＋）were prepared by a facile method under ambient conditions. Lanthanide ions were covalently grafted to the cellulose framework through coordination with the carboxylic groups of the cellulose. Hybrid materials were fabricated as hydrogel and aerogel. As shown by SEM and pore parameters, aerogel materials which were obtained by supercritical CO2 drying show hierarchical porous structure. The photoluminescence spectrum of the hybrid materials shows the characteristic red emission of Eu3＋ ion and green emission of Tb3＋. Further luminescent investigations reveal that these hybrid materials can detect Fe3＋ with relative selectivity and high sensitivity, which suggests that the hybrid materials could be a promising luminescent probe for selectively sensing Fe3＋ ion.
基金supported by National Natural Science Foundation of China(51272133,51472145,51772174 and 51472150)Shandong Natural Science Foundation(ZR2016EMM20)
文摘The CO_2 sensing of PrFeO_3 and NdFeO_3 sensors were investigated. Experimental results show that the resistances for PrFeO_3 and NdFeO_3 in CO_2 gas are larger than those in air and the responses for PrFeO_3and NdFeO_3 sensors increase with an increase in room-temperature relative humidity. When exposed to1000 ppm CO_2, the response of PrFeO_3 thick film based on nano-powders annealed at 700℃can reach8.44 at 160℃for the background of wet air with 58%of room-temperature relative humidity (RH),which is much larger than the corresponding value (3.03) in wet air with 25%RH. The sensing response S of NdFeO_3 thick-film sensor based on nano-powders annealed at 600℃to 3000 ppm CO_2 at the operating temperature 200℃can reach 2.36 for the background of wet air with 72%RH, which is larger than the corresponding value (1.83) in the air with 25%RH. Compared with other CO_2 sensing materials, the PrFeO_3 sensor has larger response at lower operating temperature for CO_2 gas and may be used as a new CO_2 sensing material.
基金Project supported by Shandong Natural Science Foundation(ZR2013EMM016)National Natural Science Foundation of China(51472145,51272133,51472150,J1103212)the Fundamental Research Funds for the Central Universities(DUT16RC(4)69)
文摘The PdC12 was mixed with nanocrystalline powders LaFeO3 and subsequently followed by an annealing of 800 ℃. PdO phase was formed and almost distributed uniformly on the surface of LaFeO3 nano-particles. With an increase of PdO amounts in composite powders, sensing sensitivity Rg/Ra to low concentration acetone or ethanol for Pd doped LaFeO3 sensors increased at first, underwent the maximum with 2 wt.% PdC12 dopant, and then doped again. Interestingly, appropriate Pd doping in LaFeO3 changed the selectivity behavior of gas sensing. LaFeO3 sensor showed good selectivity to ethanol, but 2 wt.% Pd doped LaFeO3 sensor showed good selectivity to acetone. The sensitivity for LaFeO3 at 200 ℃was 1.32 to 1 ppm ethanol, and 1.19 to 1 ppm acetone. Whereas the sensitivity for 2 wt.% Pd doped LaFeO3 at 200 ℃ was 1.53 to 1 ppm ethanol, and 1.9 to 1 ppm acetone. The 2 wt.% Pd doped LaFeO3 sensor at 200 ℃ showed very short response time （4 s） and recovery time （2 s） to 1 ppm acetone gas, respectively. Such results showed that 2 wt.% Pd doped LaFeO3 sensor is a new promising sensing candidate for detecting low concentration acetone.
基金Project supported by National Natural Science Foundation of China(51602035,51472145,51272133)the Fundamental Research Funds for the Central Universities(DUT16RC(4)69)
文摘The sol-gel method was used to prepare the nanocrystalline Gd_（1–x）Ca_xFeO_3 （x=0–0.4） powders. The XRD results showed that all the Gd_（1–x）Ca_xFeO_3 （x=0–0.4） compounds crystallized as perovskite phase with orthorhombic structure. The doping of Ca in GdFeO_3 not only reduced the resistance, but also enhanced the response to methanol. The Gd_（0.9）Ca_（0.1）FeO_3 showed the best response to methanol among Gd_（1–x）Ca_xFeO_3 sensors. Besides, it showed good selectivity to methanol among methanol, ethanol, CO and formaldehyde gases. The responses at 260 oC for Gd_（0.9）Ca_（0.1）FeO_3-based sensor to 600 ppm methanol, ethanol and CO gases were 117.7, 72.7 and 31.9, respectively. Even at quite low gas concentrations, Gd_（0.9）Ca_（0.1）FeO_3-based sensor had an obvious response. At 260 °C, the response of 1.54 was obtained to be 45 ppm methanol. The experimental results showed that nanocrystalline Gd_（0.9）Ca_（0.1）FeO_3 based sensor can be used to detect methanol gas.
基金Project supported by the National Natural Science Foundation of China (21002035)Start Funding of South China Normal University (G21117)
文摘An investigation on the photophysical properties of the newly designed terbium imidazole-4,5-dicarboxylic acid complex encapsulated in the inert matrices (tetraethoxysilane, TEOS) was performed. The composite material was very stable and showed strong green emission in pure water. Interestingly, we discovered that the luminescence of hybrid material was selectively responsive to H2PO4-. 1H-NMR and fluorescence spectra supported that the receptor had strong affinity to dihydrogen phosphate. Meanwhile, the luminescence was quenched by Fe3+ when adding different metal ions such as Fe3+, Pd2+, Cd2+, Co2+ and Mn2+ concomitantly. Moreover, thin film was successfully pre-pared by the same materials and it also exhibited selective recognition behavior to the above two ions.
文摘On the basis of the description of the rare-earth countercurrent extraction process, the on-line detecting method and equipments of rare-earth elements and the application in the process of the rare-earth countercurrent extraction are summarized. The procedure simulation of the computer, the automation control method and its current application are also mentioned in the process of rare-earth countercurrent extraction. The method of soft sensor is proposed. Optimal control method based on object-oriented rare-earth countercurrent extraction process and integrated automation system composed of process management system and process control system are presented, which are the developing direction of the automation of rare-earth countercurrent extraction process.
基金NSFC (20471055)Henan Outstanding Youth Science Fund (0612002700)
文摘Yttrium-doped SnO2 powders were successfully synthesized by solution co-precipitation method and characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The sensitivity of sensors based on Y-doped SnO2 and SnO2 nanocrystals were investigated comparatively. The results indicated that Y-doped SnO2 was with the result of enhancement of sensitivity and selectivity to ethanol and reduction of sensitivity to other gas components. The enhancements of selectivity and sensitivity could be contributed to for two reasons. The first is that rare metal yttrium has a high alkalescence and good catalysis, and the second is that the nanosized crystallite and large specific surface area of Y-doped SnO2 is advantageous for gas-diffusion control as well as an increase in active sites for gas detection.
