Reviews of long-term predictions of solar cycles have shown that a precise prediction with a lead time of 2 years or more of a solar cycle remains an unsolved problem. We used a simple method, the method of similar cy...Reviews of long-term predictions of solar cycles have shown that a precise prediction with a lead time of 2 years or more of a solar cycle remains an unsolved problem. We used a simple method, the method of similar cycles, to make long-term predictions of not only the maximum amplitude but also the smoothed monthly mean sunspot number for every month of Solar Cycle 23. We verify and compare our prediction with the latest available observational results.展开更多
The paper deals with active drive system for colonoscope. The system is mainly composed of soft mobile mechanism for earthworm locomotion and turning mechanism based on shape memory effect. The soft mobile mechanism c...The paper deals with active drive system for colonoscope. The system is mainly composed of soft mobile mechanism for earthworm locomotion and turning mechanism based on shape memory effect. The soft mobile mechanism contacts colon wall with air in inflatable balloons, so the robot has better soft and non invasive properties. The turning mechanism can be actively bent by shape memory alloy components. It ensures the colonoscope to adapt to the tortuous shape of colon. Some experiment results are given in the paper.展开更多
Boundary element compliance matrix (BEM) method to deal with 3D elastic frictional contact problem was presented, and its calculation method and convergence criteria were discussed. It has the advantages of both bound...Boundary element compliance matrix (BEM) method to deal with 3D elastic frictional contact problem was presented, and its calculation method and convergence criteria were discussed. It has the advantages of both boundary element method and compliance matrix methods: small number of inputting data, simple and convenient model, precise solution, short calculating time and requirements for a small quantity of computer memory. In comparison to the other BEM with friction problems, we obtain more precise solution and less iteration times. The effect of friction coefficient on contact area. contace state, and relative displacement, normal and tangential stress was analyzed by two examples. And because of the quickness of calculation of program and efficient method, we visualize the result in virtual reality (VR) environment. We grant the real time of VR and provide more immersion to users who ware the VR device.展开更多
This paper summarizes the long term and decadal time scale fluctuations of atmospheric circulation in the Southern(Hemisphere)middle and high latitudes.The long time series of Antarctic Oscillation Indices(AOIs)were e...This paper summarizes the long term and decadal time scale fluctuations of atmospheric circulation in the Southern(Hemisphere)middle and high latitudes.The long time series of Antarctic Oscillation Indices(AOIs)were established for January.April.July and October based on the historical sea level pressure maps and NCEP/NCAR reanalysis surface pressure data set.It was found that the AOI of January had upward trend at a rate of 1.17 hPa/100 a.and July had downward trend at a rate of—1.49 hPa/100 a since 1871.The method of wavelet analysis was applied to detect the low frequency characteristics of AOIs,and it is clear that there are decadal variations in the time scale of about 20—30 years in all 4 indices.Since the averaged value of 4 months could explain most variance of annual AOI.thus it is reasonable using the mean AOI of January,April,July and October to represent the annual AOI.The value of annual AOI was much lower in periods of about 1894—1901.1910—1935,and was much higher in periods of about 1880 —1893,1936—1945.The positive anomalies were remarkable since 1980s.Power spectra of modeled AOIs from Hadley Center Control Integration(HCCI)were compared with the observations,it is found that the interannual time scale frequencies were more significant than decadal frequencies.But.there also had the possibility for generating weak deeadal fluctuations in some special months and years by Hasselmann mechanism.展开更多
基金This work was supported by the National Natural Science Foundation of China (Grant Nos. 4999-0451 and 10073013) Space Environment Forecast Center, CSSAR, CAS.
文摘Reviews of long-term predictions of solar cycles have shown that a precise prediction with a lead time of 2 years or more of a solar cycle remains an unsolved problem. We used a simple method, the method of similar cycles, to make long-term predictions of not only the maximum amplitude but also the smoothed monthly mean sunspot number for every month of Solar Cycle 23. We verify and compare our prediction with the latest available observational results.
文摘The paper deals with active drive system for colonoscope. The system is mainly composed of soft mobile mechanism for earthworm locomotion and turning mechanism based on shape memory effect. The soft mobile mechanism contacts colon wall with air in inflatable balloons, so the robot has better soft and non invasive properties. The turning mechanism can be actively bent by shape memory alloy components. It ensures the colonoscope to adapt to the tortuous shape of colon. Some experiment results are given in the paper.
基金Natural Science Foundation of China(No.5 98895 0 5 )
文摘Boundary element compliance matrix (BEM) method to deal with 3D elastic frictional contact problem was presented, and its calculation method and convergence criteria were discussed. It has the advantages of both boundary element method and compliance matrix methods: small number of inputting data, simple and convenient model, precise solution, short calculating time and requirements for a small quantity of computer memory. In comparison to the other BEM with friction problems, we obtain more precise solution and less iteration times. The effect of friction coefficient on contact area. contace state, and relative displacement, normal and tangential stress was analyzed by two examples. And because of the quickness of calculation of program and efficient method, we visualize the result in virtual reality (VR) environment. We grant the real time of VR and provide more immersion to users who ware the VR device.
基金This research is supported by the National Key Developing Program for Basic Sciences under Grant G1998040900 the National Natural Science Foundation of China grant to Beijing Normal University.
文摘This paper summarizes the long term and decadal time scale fluctuations of atmospheric circulation in the Southern(Hemisphere)middle and high latitudes.The long time series of Antarctic Oscillation Indices(AOIs)were established for January.April.July and October based on the historical sea level pressure maps and NCEP/NCAR reanalysis surface pressure data set.It was found that the AOI of January had upward trend at a rate of 1.17 hPa/100 a.and July had downward trend at a rate of—1.49 hPa/100 a since 1871.The method of wavelet analysis was applied to detect the low frequency characteristics of AOIs,and it is clear that there are decadal variations in the time scale of about 20—30 years in all 4 indices.Since the averaged value of 4 months could explain most variance of annual AOI.thus it is reasonable using the mean AOI of January,April,July and October to represent the annual AOI.The value of annual AOI was much lower in periods of about 1894—1901.1910—1935,and was much higher in periods of about 1880 —1893,1936—1945.The positive anomalies were remarkable since 1980s.Power spectra of modeled AOIs from Hadley Center Control Integration(HCCI)were compared with the observations,it is found that the interannual time scale frequencies were more significant than decadal frequencies.But.there also had the possibility for generating weak deeadal fluctuations in some special months and years by Hasselmann mechanism.
