The un-coincide coordinate error in the single-axis rotating fiber optic strap-down inertial navigation system（SINS） is analyzed. Firstly, a rotating modulation technology is presented for SINS. The method provides ...The un-coincide coordinate error in the single-axis rotating fiber optic strap-down inertial navigation system（SINS） is analyzed. Firstly, a rotating modulation technology is presented for SINS. The method provides the enhanced property of SINS when using the same-leveled inertial measurement units. Then, the rotating struc- ture modification is derived and augmented to resolve the un-modulated error-accumulated problem. As the insuf- ficient machine processing, the horizontal and the vertical errors on the machine surface are inevitable, and the in- volved coordinates are difficult to get the exact coincident. So, two major kinds of coordinate situation are stud- ied. The equivalent error models on gyro and acceleration outputs are built for each situation, and the impact is analyzed for compensation. The part of attitude and position error models caused by the built angle-rate error is established to calculate the un-eoincident impact. Considering these conditions of different gyro accuracy and mo- tion states simultaneously, numerical simulations are implemented. Results indicate that the SINS modulation ac- curacy is seriously affected by the combined factors on gyro accuracy and motion conditions.展开更多
Micron-size superparamagnetic poly(styrene-divinylbenzene-glycidyl methacrylate) (PSt-DVB-GMA) spheres were prepared via a modified suspension copolymerization method. Oleic acid coated magnetite (Fe3O4 nanoparticles ...Micron-size superparamagnetic poly(styrene-divinylbenzene-glycidyl methacrylate) (PSt-DVB-GMA) spheres were prepared via a modified suspension copolymerization method. Oleic acid coated magnetite (Fe3O4 nanoparticles made by co-precipitation were first mixed with monomers of St, DVB, GMA, and benzoyl peroxide (BPO) to form oil in water suspension with the presence of poly(viny) pyrrolidone) (PVP-K30) as a stabilizer. Then the temperature of mixture was increased at a controlled rate to obtain small and relatively uniform droplets. Finally, the copolymerization reaction was initiated by the decomposition of BPO. The morphology and properties of magnetic PSt-DVB-GMA microspheres were examined by SEM, TEM, VSM, XRD and FT-IR. The magnetic microspheres obtained have very small size (about 4-7μm) in diameter with narrow size distribution and super-paramagnetic characteristics. Powder X-ray diffraction measurements show the inverse cubic spinel structure for the magnetite dispersed in polymer microspheres. FT-IR spectroscopy indicates extensive oxirane groups existed on the surface of magnetic PSt-DVB-GMA microspheres.展开更多
A novel fabrication process for micro patterns with curvature was introduced. The curved structures were made by compensating rectangular micro structures with liquid photoresist layer. Because of the surface tension ...A novel fabrication process for micro patterns with curvature was introduced. The curved structures were made by compensating rectangular micro structures with liquid photoresist layer. Because of the surface tension of the liquid in micro scale, various shapes of meniscus can he made on the micro channels. The micro channels were made on the silicon suhstrate in advance, and then the liquid layer was coated on the micro channels. From the nature of liquid behavior, the curved patterns with smooth surface are obtained, which cannot be made easily with the conventional mechanical machining, as well as with the microfabrication processes, such as wet and dry etching. With this principle, it is expected that the smooth and curved surfaces can be made by simple processes and the results can be applied widely, such as optical patterns.展开更多
An investigation was carried out to eliminate the decrease of effluent pH value in carbon filter in O3-biological activated carbon process. The influence factors were examined in a pilot test, and pH was adjusted in t...An investigation was carried out to eliminate the decrease of effluent pH value in carbon filter in O3-biological activated carbon process. The influence factors were examined in a pilot test, and pH was adjusted in the pilot and waterworks. Results show that the carbon filter is an acid-base buffer system and the activated carbon is the key factor. Chemical functional groups on activated carbon surface present acid-base properties to buffer the water but decrease with time, so that effluent pH value decreases. The effects of ozone dosage, CO2 in the carbon filter, and the filter influent quality are negligible. A new method to adjust pH is developed: the activated carbon is first modified by soaking in sodium hydroxide solution to make its pH reach the desired value, and then the pH value of inflow is controlled to certain value by dosing lime in sand filter influent. The method is economical and effective.展开更多
基金Supported by the National Natural Science Foundation of China(60702003)the Aviation Science Foundation(20080852011)+1 种基金the Specialized Research Fund for the Doctoral Program of Higher Education of China(20070287045)the NUAA Research Fundation(NS2010066)~~
文摘The un-coincide coordinate error in the single-axis rotating fiber optic strap-down inertial navigation system（SINS） is analyzed. Firstly, a rotating modulation technology is presented for SINS. The method provides the enhanced property of SINS when using the same-leveled inertial measurement units. Then, the rotating struc- ture modification is derived and augmented to resolve the un-modulated error-accumulated problem. As the insuf- ficient machine processing, the horizontal and the vertical errors on the machine surface are inevitable, and the in- volved coordinates are difficult to get the exact coincident. So, two major kinds of coordinate situation are stud- ied. The equivalent error models on gyro and acceleration outputs are built for each situation, and the impact is analyzed for compensation. The part of attitude and position error models caused by the built angle-rate error is established to calculate the un-eoincident impact. Considering these conditions of different gyro accuracy and mo- tion states simultaneously, numerical simulations are implemented. Results indicate that the SINS modulation ac- curacy is seriously affected by the combined factors on gyro accuracy and motion conditions.
基金Supported by the High-Technology Research and Development Program of China(No.2002AA302211)and the National Natural science Foundation of China(No.20206032)
文摘Micron-size superparamagnetic poly(styrene-divinylbenzene-glycidyl methacrylate) (PSt-DVB-GMA) spheres were prepared via a modified suspension copolymerization method. Oleic acid coated magnetite (Fe3O4 nanoparticles made by co-precipitation were first mixed with monomers of St, DVB, GMA, and benzoyl peroxide (BPO) to form oil in water suspension with the presence of poly(viny) pyrrolidone) (PVP-K30) as a stabilizer. Then the temperature of mixture was increased at a controlled rate to obtain small and relatively uniform droplets. Finally, the copolymerization reaction was initiated by the decomposition of BPO. The morphology and properties of magnetic PSt-DVB-GMA microspheres were examined by SEM, TEM, VSM, XRD and FT-IR. The magnetic microspheres obtained have very small size (about 4-7μm) in diameter with narrow size distribution and super-paramagnetic characteristics. Powder X-ray diffraction measurements show the inverse cubic spinel structure for the magnetite dispersed in polymer microspheres. FT-IR spectroscopy indicates extensive oxirane groups existed on the surface of magnetic PSt-DVB-GMA microspheres.
基金the support of Ministry of Knowledge and Economy through Strategic Technology Development ProjectConversing Research Center Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education, Science and Technology
文摘A novel fabrication process for micro patterns with curvature was introduced. The curved structures were made by compensating rectangular micro structures with liquid photoresist layer. Because of the surface tension of the liquid in micro scale, various shapes of meniscus can he made on the micro channels. The micro channels were made on the silicon suhstrate in advance, and then the liquid layer was coated on the micro channels. From the nature of liquid behavior, the curved patterns with smooth surface are obtained, which cannot be made easily with the conventional mechanical machining, as well as with the microfabrication processes, such as wet and dry etching. With this principle, it is expected that the smooth and curved surfaces can be made by simple processes and the results can be applied widely, such as optical patterns.
基金Supported by the National Water Pollution Control and Harnessing Projects (2009ZX07423-003)
文摘An investigation was carried out to eliminate the decrease of effluent pH value in carbon filter in O3-biological activated carbon process. The influence factors were examined in a pilot test, and pH was adjusted in the pilot and waterworks. Results show that the carbon filter is an acid-base buffer system and the activated carbon is the key factor. Chemical functional groups on activated carbon surface present acid-base properties to buffer the water but decrease with time, so that effluent pH value decreases. The effects of ozone dosage, CO2 in the carbon filter, and the filter influent quality are negligible. A new method to adjust pH is developed: the activated carbon is first modified by soaking in sodium hydroxide solution to make its pH reach the desired value, and then the pH value of inflow is controlled to certain value by dosing lime in sand filter influent. The method is economical and effective.
