In order to improve the prediction accuracy and test the generalization ability of the dam deformation analysis model, the back-propagation(BP) neural network model for dam deformation analysis is studied, and the m...In order to improve the prediction accuracy and test the generalization ability of the dam deformation analysis model, the back-propagation(BP) neural network model for dam deformation analysis is studied, and the merging model is built based on the neural network BP algorithm and the traditional statistical model. The three models mentioned above are calculated and analyzed according to the long-term deformation observation data in Chencun Dam. The analytical results show that the average prediction accuracies of the statistical model and the BP neural network model are ~ 0.477 and +- 0.390 mm, respectively, while the prediction accuracy of the merging model is ~0. 318 mm, which is improved by 33% and 18% compared to the other two models, respectively. And the merging model has a better generalization ability and broad applicability.展开更多
Hot compression tests in the temperature range of 340-450 ℃ and strain rate range of 0.001-1 s^-1 of spray-formed 7055 aluminum alloy were carried out to study its hot deformation behavior. Three phenomenological mod...Hot compression tests in the temperature range of 340-450 ℃ and strain rate range of 0.001-1 s^-1 of spray-formed 7055 aluminum alloy were carried out to study its hot deformation behavior. Three phenomenological models including Johnson-Cook, modified Fields-Backofen and Arrhenius-type were introduced to predict the flow stresses during the compression process. And then, a comparative predictability of the phenomenological models was estimated in terms of the relative errors, correlation coefficient(R), and average absolute relative error(AARE). The results indicate that Johnson-Cook model and modified Fields-Backofen model cannot well predict the hot deformation behavior due to the large deviation in the process of line regression fitting. Arrhenius-type model obtains the best fit through combining the effect of strain rate and temperature.展开更多
A series of laboratory screening tests have been performed with the objective of evalu-ating the effect of feed rate, screen length and screen motion on the quality of separation achieved. The statistic analysis and r...A series of laboratory screening tests have been performed with the objective of evalu-ating the effect of feed rate, screen length and screen motion on the quality of separation achieved. The statistic analysis and results derived from it are discussed. Suggestions for future work with the objective of assessing the industrial significance of the research to the optimisation and design of screening processes are presented.展开更多
Australian dollar (AUD) maintains a fluctuant increase for long period, but in recent two years, this currency represents an anomalistic change. In order to forecast the trend of AUD, this essay examines the exchang...Australian dollar (AUD) maintains a fluctuant increase for long period, but in recent two years, this currency represents an anomalistic change. In order to forecast the trend of AUD, this essay examines the exchange rate of AUD in then years from March of 2000 to March of 2010, and argues the factors which create these trend changes. By means of secondary research and graphs analysis, the relevant evidence and argument was selected into four terms below: relative raw materials prices changes, relative domestic price level and Import-Expert changes, relative interest rate changes, and other factors. The examples based on the theoretics, graphs, statistics and experts' opinions.展开更多
Sea ice deformation parameters are important for elucidation of the properties and characteristics of ice-ocean models.Observations of sea ice motion over 11.5 year period(November 1996–April 2008) are used to calcul...Sea ice deformation parameters are important for elucidation of the properties and characteristics of ice-ocean models.Observations of sea ice motion over 11.5 year period(November 1996–April 2008) are used to calculate ice motion divergence and shear rates, and thus, to construct total deformation rate(TDR) estimates with respect to spatial and temporal variability in the Arctic Ocean. Strong sea ice deformation signal(SDS) rates are identified when TDR>0.01 day^(-1), and very strong SDS events,when TDR>0.05 day^(-1). These calculations are based on measurements made by the RADARSAT-1 Geophysical Processer System(RGPS). Statistical analysis of the SDS data suggest the following features:(1) Mean SDS and the SDS probability distributions are larger in "low latitudes" of the Arctic Ocean(less than 80°N) than in "high latitudes"(above 80°N), in both summer and winter;(2) very high SDS probabilities distributions and mean SDS values occur in coastal areas, e.g. the East Siberian Sea, Chukchi Sea and Beaufort Sea;(3) areas with relatively low TDR values, in the range from 0.01 day^(-1) to 0.05 day^(-1), cover much of the Arctic Ocean, in summer and winter;(4) of the entire TDR dataset, 45.89% belong to SDS, with summer the SDS percentage, 59.06%,and the winter SDS percentage, 40.50%. Statistically, the summer mean SDS, SDS percentage and very strong SDS are larger than corresponding values in the winter for each year, and show slight increasing tendencies during the years from 1997 to 2007.These results suggest important constraints for accurate simulations of very strong SDS in ice-ocean models.展开更多
[Abstract] Objective: By studying the mode and morphologic character of high fall injuries on the scene, and exploring the injury situation of different heights, different fall ways and postures, to provide a referen...[Abstract] Objective: By studying the mode and morphologic character of high fall injuries on the scene, and exploring the injury situation of different heights, different fall ways and postures, to provide a reference for the foren- sic identification of high fall injury. Methods: All the high fall cases were statistically analysed according to their gender, age, ground-touching posture, fall height, site and type of the injury. Results: Among 134 high fall cases, 98 were male and 36 were female with the age ranging from 2-71 years (37.6 +16.9 on average), in which, 10-60 years old group con- sisted of 110 cases (82%). Most cases fell from windows orroofs (73%) and the touching objects were cement ground or shaft bottom of elevators. Among these cases, head injury was generally serious, followed by chest and abdominal injuries. The morphologic changes depend upon the height, nature, as well as the posture at the point while the body touches the ground. Conclusion: Morphologic study of high fall injury assists medicolegal physicians to make correct identifica- tions of the cause and nature of high fall injuries.展开更多
基金The Scientific Innovation Research of College Graduates in Jiangsu Province(No.CXLX11_0143)
文摘In order to improve the prediction accuracy and test the generalization ability of the dam deformation analysis model, the back-propagation(BP) neural network model for dam deformation analysis is studied, and the merging model is built based on the neural network BP algorithm and the traditional statistical model. The three models mentioned above are calculated and analyzed according to the long-term deformation observation data in Chencun Dam. The analytical results show that the average prediction accuracies of the statistical model and the BP neural network model are ~ 0.477 and +- 0.390 mm, respectively, while the prediction accuracy of the merging model is ~0. 318 mm, which is improved by 33% and 18% compared to the other two models, respectively. And the merging model has a better generalization ability and broad applicability.
基金Project(2013HH100055) supported by the Basic Research and Science and Technology Innovation Fund of Foshan City,China
文摘Hot compression tests in the temperature range of 340-450 ℃ and strain rate range of 0.001-1 s^-1 of spray-formed 7055 aluminum alloy were carried out to study its hot deformation behavior. Three phenomenological models including Johnson-Cook, modified Fields-Backofen and Arrhenius-type were introduced to predict the flow stresses during the compression process. And then, a comparative predictability of the phenomenological models was estimated in terms of the relative errors, correlation coefficient(R), and average absolute relative error(AARE). The results indicate that Johnson-Cook model and modified Fields-Backofen model cannot well predict the hot deformation behavior due to the large deviation in the process of line regression fitting. Arrhenius-type model obtains the best fit through combining the effect of strain rate and temperature.
文摘A series of laboratory screening tests have been performed with the objective of evalu-ating the effect of feed rate, screen length and screen motion on the quality of separation achieved. The statistic analysis and results derived from it are discussed. Suggestions for future work with the objective of assessing the industrial significance of the research to the optimisation and design of screening processes are presented.
文摘Australian dollar (AUD) maintains a fluctuant increase for long period, but in recent two years, this currency represents an anomalistic change. In order to forecast the trend of AUD, this essay examines the exchange rate of AUD in then years from March of 2000 to March of 2010, and argues the factors which create these trend changes. By means of secondary research and graphs analysis, the relevant evidence and argument was selected into four terms below: relative raw materials prices changes, relative domestic price level and Import-Expert changes, relative interest rate changes, and other factors. The examples based on the theoretics, graphs, statistics and experts' opinions.
基金supported by the Global Change Research Program of China (Grant No. 2015CB953901)the National Key Research and Development Program of China (Grant No. 2016YFC1401007)the Canadian Program on Energy Research and Development (OERD), the Office of Naval Research (Code 322, “Arctic and Global Prediction”, Grant Number and Principal Investigator: William Perrie, Grant No. N00014-15-1-2611)
文摘Sea ice deformation parameters are important for elucidation of the properties and characteristics of ice-ocean models.Observations of sea ice motion over 11.5 year period(November 1996–April 2008) are used to calculate ice motion divergence and shear rates, and thus, to construct total deformation rate(TDR) estimates with respect to spatial and temporal variability in the Arctic Ocean. Strong sea ice deformation signal(SDS) rates are identified when TDR>0.01 day^(-1), and very strong SDS events,when TDR>0.05 day^(-1). These calculations are based on measurements made by the RADARSAT-1 Geophysical Processer System(RGPS). Statistical analysis of the SDS data suggest the following features:(1) Mean SDS and the SDS probability distributions are larger in "low latitudes" of the Arctic Ocean(less than 80°N) than in "high latitudes"(above 80°N), in both summer and winter;(2) very high SDS probabilities distributions and mean SDS values occur in coastal areas, e.g. the East Siberian Sea, Chukchi Sea and Beaufort Sea;(3) areas with relatively low TDR values, in the range from 0.01 day^(-1) to 0.05 day^(-1), cover much of the Arctic Ocean, in summer and winter;(4) of the entire TDR dataset, 45.89% belong to SDS, with summer the SDS percentage, 59.06%,and the winter SDS percentage, 40.50%. Statistically, the summer mean SDS, SDS percentage and very strong SDS are larger than corresponding values in the winter for each year, and show slight increasing tendencies during the years from 1997 to 2007.These results suggest important constraints for accurate simulations of very strong SDS in ice-ocean models.
基金The paper was supported by the National Natural Science Foundation of China,the Natural Science Foundation of Chongqing of China,the Key Projects Foundation of the Ministry of Public Security
文摘[Abstract] Objective: By studying the mode and morphologic character of high fall injuries on the scene, and exploring the injury situation of different heights, different fall ways and postures, to provide a reference for the foren- sic identification of high fall injury. Methods: All the high fall cases were statistically analysed according to their gender, age, ground-touching posture, fall height, site and type of the injury. Results: Among 134 high fall cases, 98 were male and 36 were female with the age ranging from 2-71 years (37.6 +16.9 on average), in which, 10-60 years old group con- sisted of 110 cases (82%). Most cases fell from windows orroofs (73%) and the touching objects were cement ground or shaft bottom of elevators. Among these cases, head injury was generally serious, followed by chest and abdominal injuries. The morphologic changes depend upon the height, nature, as well as the posture at the point while the body touches the ground. Conclusion: Morphologic study of high fall injury assists medicolegal physicians to make correct identifica- tions of the cause and nature of high fall injuries.