Bioimplants are becoming increasingly impor-tant in the modem society due to the fact of an agingpopulation and associated issues of osteoporosis andosteoarthritis. The manufacturing of bioimplants involvesan understa...Bioimplants are becoming increasingly impor-tant in the modem society due to the fact of an agingpopulation and associated issues of osteoporosis andosteoarthritis. The manufacturing of bioimplants involvesan understanding of both mechanical engineering andbiomedical science to produce biocompatible products withadequate lifespans. A suitable selection of materials is theprerequisite for a long-term and reliable service of thebioimplants, which relies highly on the comprehensiveunderstanding of the material properties. In this paper,most biomaterials used for bioimplants are reviewed. Thetypical manufacturing processes are discussed in order toprovide a perspective on the development of manufacturingfundamentals and latest technologies. The review alsocontains a discussion on the current measurement andevaluation constraints of the finished bioimplant products.Potential future research areas are presented at the end ofthis paper.展开更多
The visibility for low earth orbit（LEO） satellites provided by the BeiDou-2 system is analyzed and compared with the global positioning system（GPS）. In addition, the spaceborne receivers＇ observations are simulat...The visibility for low earth orbit（LEO） satellites provided by the BeiDou-2 system is analyzed and compared with the global positioning system（GPS）. In addition, the spaceborne receivers＇ observations are simulated by the BeiDou satellites broadcast ephemeris and LEO satellites orbits. The precise orbit determination（POD） results show that the along-track component accuracy is much better over the service area than the non-service area, while the accuracy of the other two directions keeps at the same level over different areas. However, the 3-dimensional（3D） accuracy over the two areas shows almost no difference. Only taking into consideration the observation noise and navigation satellite ephemeris errors, the 3D accuracy of the POD is about30 cm. As for the precise relative orbit determination（PROD）, the 3D accuracy is much better over the eastern hemisphere than that of the western hemisphere. The baseline length accuracy is 3.4 mm over the service area, and it is still better than 1 cm over the non-service area. This paper demonstrates that the BeiDou regional constellation could provide global service to LEO satellites for the POD and the PROD. Finally, the benefit of geostationary earth orbit（GEO） satellites is illustrated for POD.展开更多
文摘Bioimplants are becoming increasingly impor-tant in the modem society due to the fact of an agingpopulation and associated issues of osteoporosis andosteoarthritis. The manufacturing of bioimplants involvesan understanding of both mechanical engineering andbiomedical science to produce biocompatible products withadequate lifespans. A suitable selection of materials is theprerequisite for a long-term and reliable service of thebioimplants, which relies highly on the comprehensiveunderstanding of the material properties. In this paper,most biomaterials used for bioimplants are reviewed. Thetypical manufacturing processes are discussed in order toprovide a perspective on the development of manufacturingfundamentals and latest technologies. The review alsocontains a discussion on the current measurement andevaluation constraints of the finished bioimplant products.Potential future research areas are presented at the end ofthis paper.
基金co-supported by the National Natural Science Foundation of China (Nos: 61002033, 61370013)the Program for New Century Excellent Talents in University and the Scientific Research Foundation for the Returned Overseas Chinese Scholars of Ministry of Education of China
文摘The visibility for low earth orbit（LEO） satellites provided by the BeiDou-2 system is analyzed and compared with the global positioning system（GPS）. In addition, the spaceborne receivers＇ observations are simulated by the BeiDou satellites broadcast ephemeris and LEO satellites orbits. The precise orbit determination（POD） results show that the along-track component accuracy is much better over the service area than the non-service area, while the accuracy of the other two directions keeps at the same level over different areas. However, the 3-dimensional（3D） accuracy over the two areas shows almost no difference. Only taking into consideration the observation noise and navigation satellite ephemeris errors, the 3D accuracy of the POD is about30 cm. As for the precise relative orbit determination（PROD）, the 3D accuracy is much better over the eastern hemisphere than that of the western hemisphere. The baseline length accuracy is 3.4 mm over the service area, and it is still better than 1 cm over the non-service area. This paper demonstrates that the BeiDou regional constellation could provide global service to LEO satellites for the POD and the PROD. Finally, the benefit of geostationary earth orbit（GEO） satellites is illustrated for POD.
