风力发电机组法兰连接的增速齿轮箱与主轴对中装配过程中,调整两个部件之间的对中精度是保证设备整体正常运行的技术要求之一。采用两套激光对中仪配合对中调整工装的使用,可以快速、精确地实现对增速齿轮箱 X 轴、Y 轴和 Z 轴 3 个方...风力发电机组法兰连接的增速齿轮箱与主轴对中装配过程中,调整两个部件之间的对中精度是保证设备整体正常运行的技术要求之一。采用两套激光对中仪配合对中调整工装的使用,可以快速、精确地实现对增速齿轮箱 X 轴、Y 轴和 Z 轴 3 个方向的调整,从而满足增速齿轮箱与主轴的对中精度要求,提高生产效率。同样,该方法也适用于其他大尺寸、重型法兰连接设备之间的对中调整。展开更多
Attractabilities of different diets and dietary selectivity of Chinese shrimp, Fenneropenaeus chinensis were studied through behavior observation and feeding experiment, respectively. The five diets used in the experi...Attractabilities of different diets and dietary selectivity of Chinese shrimp, Fenneropenaeus chinensis were studied through behavior observation and feeding experiment, respectively. The five diets used in the experiment are: Fish Flesh (FF), Shrimp Flesh (SF), Clam Foot (CF), Polychaete Worm (PW), and Formulated Diet (FD). No significant differ- ences of attractability exist between any two different diets when every two natural diets or all five diets are provided simul- taneously. On the other hand, significant differences of attractability exist between FD and every single natural diet when they are provided simultaneously. Results of behavioral observation indicate that natural diets are more attractive than FD. In feeding experiment, Chinese shrimp has distinct selectivity on different diets. It positively selects CF and PW, negatively selects FF and SF, and excludes FD absolutely. The results of the present studies indicate that the dietary selectivity of shrimp was based not only on the attractabilities of the diets, but also on the responses such as growth and food conversion.展开更多
In this paper, we conduct research on the prevention methodologies and environmental protection countermeasures for oil pollution based on latest techniques from China and abroad. Petroleum and petrochemical industry ...In this paper, we conduct research on the prevention methodologies and environmental protection countermeasures for oil pollution based on latest techniques from China and abroad. Petroleum and petrochemical industry will also be able to have serious water pollution. Against oil pollution increasingly serious phenomenon, about how to control oil pollution has also carried on the thorough research and accumulated in the process of specific management experiences and lessons. We conduct theoretical analysis between the state-of-the-art methods of environmental protection countermeasures with examples, We firmly believe that more advances will occur in the future.展开更多
Due to the complexity of economic system and the interactive effects between all kinds of economic variables and foreign trade, it is not easy to predict foreign trade volume. However, the difficulty in predicting for...Due to the complexity of economic system and the interactive effects between all kinds of economic variables and foreign trade, it is not easy to predict foreign trade volume. However, the difficulty in predicting foreign trade volume is usually attributed to the limitation of many conventional forecasting models. To improve the prediction performance, the study proposes a novel kernel-based ensemble learning approach hybridizing econometric models and artificial intelligence (AI) models to predict China's foreign trade volume. In the proposed approach, an important econometric model, the co-integration-based error correction vector auto-regression (EC-VAR) model is first used to capture the impacts of all kinds of economic variables on Chinese foreign trade from a multivariate linear anal- ysis perspective. Then an artificial neural network (ANN) based EC-VAR model is used to capture the nonlinear effects of economic variables on foreign trade from the nonlinear viewpoint. Subsequently, for incorporating the effects of irregular events on foreign trade, the text mining and expert's judgmental adjustments are also integrated into the nonlinear ANN-based EC-VAR model. Finally, all kinds of economic variables, the outputs of linear and nonlinear EC-VAR models and judgmental adjustment model are used as input variables of a typical kernel-based support vector regression (SVR) for en- semble prediction purpose. For illustration, the proposed kernel-based ensemble learning methodology hybridizing econometric techniques and AI methods is applied to China's foreign trade volume predic- tion problem. Experimental results reveal that the hybrid econometric-AI ensemble learning approach can significantly improve the prediction performance over other linear and nonlinear models listed in this study.展开更多
Piezoelectric nanogenerators(NGs)have been developed for converting mechanical energy into electric energy using ZnO,GaN,ZnSnO3,and PZT nanowires.Due to the unique polarity and non-central symmetry of the wurtzite str...Piezoelectric nanogenerators(NGs)have been developed for converting mechanical energy into electric energy using ZnO,GaN,ZnSnO3,and PZT nanowires.Due to the unique polarity and non-central symmetry of the wurtzite structure,a composite made of using the conical shaped nanowires are used as a simple,cost-effective,and scalable nanogenerator.Based on the finite element methods,the output voltage of the nanogenerator is modeled numerically.The key factors:the spatial location of nanowires,length and dip angle of nanowires,thickness of NG devices,and the physical properties of the polymer inside NGs,which affect the output voltage are studied.The results provide guidance for optimization the output of piezoelectric nanogenerators.展开更多
文摘风力发电机组法兰连接的增速齿轮箱与主轴对中装配过程中,调整两个部件之间的对中精度是保证设备整体正常运行的技术要求之一。采用两套激光对中仪配合对中调整工装的使用,可以快速、精确地实现对增速齿轮箱 X 轴、Y 轴和 Z 轴 3 个方向的调整,从而满足增速齿轮箱与主轴的对中精度要求,提高生产效率。同样,该方法也适用于其他大尺寸、重型法兰连接设备之间的对中调整。
基金the Major State Basic Research of China(Grant No.G1999012011)the State Agriculture Program(Grant No.K2002-16) the Initializing Fund for Teachers of Ocean University of China.
文摘Attractabilities of different diets and dietary selectivity of Chinese shrimp, Fenneropenaeus chinensis were studied through behavior observation and feeding experiment, respectively. The five diets used in the experiment are: Fish Flesh (FF), Shrimp Flesh (SF), Clam Foot (CF), Polychaete Worm (PW), and Formulated Diet (FD). No significant differ- ences of attractability exist between any two different diets when every two natural diets or all five diets are provided simul- taneously. On the other hand, significant differences of attractability exist between FD and every single natural diet when they are provided simultaneously. Results of behavioral observation indicate that natural diets are more attractive than FD. In feeding experiment, Chinese shrimp has distinct selectivity on different diets. It positively selects CF and PW, negatively selects FF and SF, and excludes FD absolutely. The results of the present studies indicate that the dietary selectivity of shrimp was based not only on the attractabilities of the diets, but also on the responses such as growth and food conversion.
文摘In this paper, we conduct research on the prevention methodologies and environmental protection countermeasures for oil pollution based on latest techniques from China and abroad. Petroleum and petrochemical industry will also be able to have serious water pollution. Against oil pollution increasingly serious phenomenon, about how to control oil pollution has also carried on the thorough research and accumulated in the process of specific management experiences and lessons. We conduct theoretical analysis between the state-of-the-art methods of environmental protection countermeasures with examples, We firmly believe that more advances will occur in the future.
基金the National Natural Science Foundation of China under Grant Nos.70601029 and 70221001the Knowledge Innovation Program of the Chinese Academy of Sciences under Grant Nos.3547600,3046540,and 3047540the Strategy Research Grant of City University of Hong Kong under Grant No.7001806
文摘Due to the complexity of economic system and the interactive effects between all kinds of economic variables and foreign trade, it is not easy to predict foreign trade volume. However, the difficulty in predicting foreign trade volume is usually attributed to the limitation of many conventional forecasting models. To improve the prediction performance, the study proposes a novel kernel-based ensemble learning approach hybridizing econometric models and artificial intelligence (AI) models to predict China's foreign trade volume. In the proposed approach, an important econometric model, the co-integration-based error correction vector auto-regression (EC-VAR) model is first used to capture the impacts of all kinds of economic variables on Chinese foreign trade from a multivariate linear anal- ysis perspective. Then an artificial neural network (ANN) based EC-VAR model is used to capture the nonlinear effects of economic variables on foreign trade from the nonlinear viewpoint. Subsequently, for incorporating the effects of irregular events on foreign trade, the text mining and expert's judgmental adjustments are also integrated into the nonlinear ANN-based EC-VAR model. Finally, all kinds of economic variables, the outputs of linear and nonlinear EC-VAR models and judgmental adjustment model are used as input variables of a typical kernel-based support vector regression (SVR) for en- semble prediction purpose. For illustration, the proposed kernel-based ensemble learning methodology hybridizing econometric techniques and AI methods is applied to China's foreign trade volume predic- tion problem. Experimental results reveal that the hybrid econometric-AI ensemble learning approach can significantly improve the prediction performance over other linear and nonlinear models listed in this study.
文摘Piezoelectric nanogenerators(NGs)have been developed for converting mechanical energy into electric energy using ZnO,GaN,ZnSnO3,and PZT nanowires.Due to the unique polarity and non-central symmetry of the wurtzite structure,a composite made of using the conical shaped nanowires are used as a simple,cost-effective,and scalable nanogenerator.Based on the finite element methods,the output voltage of the nanogenerator is modeled numerically.The key factors:the spatial location of nanowires,length and dip angle of nanowires,thickness of NG devices,and the physical properties of the polymer inside NGs,which affect the output voltage are studied.The results provide guidance for optimization the output of piezoelectric nanogenerators.
