Data of 44 glacier systems in China used in this paper were obtained from Chinese Glacier Inventories and the meteorological data were got from Meteorological Atlas of Plateau of west China. Based on the statistical a...Data of 44 glacier systems in China used in this paper were obtained from Chinese Glacier Inventories and the meteorological data were got from Meteorological Atlas of Plateau of west China. Based on the statistical analysis and functional model simulation results of the 44 glacier systems in China, the glacier systems were divided into extremely-sensitive glacier system, semi-sensitive glacier system, extremely-steady glacier system and semi-steady glacier system in terms of glacier system＇s level of water-energy exchange, rising gradient of the equilibrium line altitudes and retreating rate of area to climate warming, their median size and vertical span distribution, and their runoff characteristics to climate warming. Furthermore the functional model of glacier system to climate warming was applied in this paper to predict the average variation trends of the 4 types of glacier systems, which indicate that different sensitivity types of glacier systems respond to the climate warming differently.展开更多
The studies on prediction of climate in Xinjiang almost show that the precipitation would increase in the coming 50 years, although there were surely some uncertainties in precipitation predictions. On the basis of th...The studies on prediction of climate in Xinjiang almost show that the precipitation would increase in the coming 50 years, although there were surely some uncertainties in precipitation predictions. On the basis of the structure of glacier system and nature of equilibrium line altitude at steady state (ELA0), a functional model of the glacier system responding to climate changes was established, and itsimultaneously involved the rising of summer mean temperature and increasing of mean precipitation. The results from the functional model under the climatic scenarios with temperature increasing rates of 0.01, 0.03 and 0.05 K/year indicated that the precipitation increasing would play an evident role in glacier system responding to climate change: if temperature become 1℃ higher, the precipitation would be increased by 10 %, which can slow down the glaciers retreating rate in the area by 4 %, accelerate runoff increasing rate by 8 % and depress the ELA0rising gradient by 24 m in northern Xinjiang glacier system where semi-continental glaciers dominate, while it has corresponding values of only 1 %, 5 % and 18m respectively in southern Xinjiang glacier system, where extremely continental glaciers dominate.展开更多
Because of the discrepancy of project types,the project progress curves present different characteristics.Studying project progress curves can reduce management risk of project and overall grasp the enforcement condit...Because of the discrepancy of project types,the project progress curves present different characteristics.Studying project progress curves can reduce management risk of project and overall grasp the enforcement condition of the project.Combining project characteristic,this paper reaches 4 kinds of project progress curve patterns.If the front of the progress curve is concave,and its rear is protruding in the break point,it is named as S model.If its front is protruding and its rear is concave in the break point,it is named as the reverse side of S model.If the front and rear are concave in the break point,it is named as J model,and two half sections are both upward protruding,it is named as the reverse side of J model.Through a case study,it shows that application project progress curve model can better raise project management.展开更多
A scraper conveyor is a kind of heavy machinery which can continuously transport goods and widely used in mines, ports and store enterprises. Since scraper failure rate directly affects production costs and production...A scraper conveyor is a kind of heavy machinery which can continuously transport goods and widely used in mines, ports and store enterprises. Since scraper failure rate directly affects production costs and production capacity, the evaluation and the prediction of scraper conveyor reliability are important for these enterprises. In this paper, the reliabilities of different parts are classified and discussed according to their structural characteristics and different failure factors. Based on the component＇s time-to-failure density function, the reliability model of scraper chain is constructed to track the age distribution of part population and the reliability change of the scraper chain. Based on the stress-strength interference model, considering the decrease of strength due to fatigue failure, the dynamic reliability model of such component as gear, axis is developed to observe the change of the part reliability with the service time of scraper. Finally, system reliability model of the scraper is established for the maintenance to simulate and calculate the scraper reliability.展开更多
基金Knowledge Innovation Project of the CAS, No.KZCX2-YW-301National Basic S&T Project of the Ministry of Science and Technology of the People's Republic of China,No.2006FY110200National Natural Science Foundation of China,No.4084002
文摘Data of 44 glacier systems in China used in this paper were obtained from Chinese Glacier Inventories and the meteorological data were got from Meteorological Atlas of Plateau of west China. Based on the statistical analysis and functional model simulation results of the 44 glacier systems in China, the glacier systems were divided into extremely-sensitive glacier system, semi-sensitive glacier system, extremely-steady glacier system and semi-steady glacier system in terms of glacier system＇s level of water-energy exchange, rising gradient of the equilibrium line altitudes and retreating rate of area to climate warming, their median size and vertical span distribution, and their runoff characteristics to climate warming. Furthermore the functional model of glacier system to climate warming was applied in this paper to predict the average variation trends of the 4 types of glacier systems, which indicate that different sensitivity types of glacier systems respond to the climate warming differently.
基金supported by grants from the National Natural Science Foundation of China(40371027).
文摘The studies on prediction of climate in Xinjiang almost show that the precipitation would increase in the coming 50 years, although there were surely some uncertainties in precipitation predictions. On the basis of the structure of glacier system and nature of equilibrium line altitude at steady state (ELA0), a functional model of the glacier system responding to climate changes was established, and itsimultaneously involved the rising of summer mean temperature and increasing of mean precipitation. The results from the functional model under the climatic scenarios with temperature increasing rates of 0.01, 0.03 and 0.05 K/year indicated that the precipitation increasing would play an evident role in glacier system responding to climate change: if temperature become 1℃ higher, the precipitation would be increased by 10 %, which can slow down the glaciers retreating rate in the area by 4 %, accelerate runoff increasing rate by 8 % and depress the ELA0rising gradient by 24 m in northern Xinjiang glacier system where semi-continental glaciers dominate, while it has corresponding values of only 1 %, 5 % and 18m respectively in southern Xinjiang glacier system, where extremely continental glaciers dominate.
文摘Because of the discrepancy of project types,the project progress curves present different characteristics.Studying project progress curves can reduce management risk of project and overall grasp the enforcement condition of the project.Combining project characteristic,this paper reaches 4 kinds of project progress curve patterns.If the front of the progress curve is concave,and its rear is protruding in the break point,it is named as S model.If its front is protruding and its rear is concave in the break point,it is named as the reverse side of S model.If the front and rear are concave in the break point,it is named as J model,and two half sections are both upward protruding,it is named as the reverse side of J model.Through a case study,it shows that application project progress curve model can better raise project management.
基金supported by National Natural Science Foundationof China under Grant No. 50875082Plan Project of Hunan Provincial Science and Technology under Grant No.2009FJ3160
文摘A scraper conveyor is a kind of heavy machinery which can continuously transport goods and widely used in mines, ports and store enterprises. Since scraper failure rate directly affects production costs and production capacity, the evaluation and the prediction of scraper conveyor reliability are important for these enterprises. In this paper, the reliabilities of different parts are classified and discussed according to their structural characteristics and different failure factors. Based on the component＇s time-to-failure density function, the reliability model of scraper chain is constructed to track the age distribution of part population and the reliability change of the scraper chain. Based on the stress-strength interference model, considering the decrease of strength due to fatigue failure, the dynamic reliability model of such component as gear, axis is developed to observe the change of the part reliability with the service time of scraper. Finally, system reliability model of the scraper is established for the maintenance to simulate and calculate the scraper reliability.
