快堆(Fast Reactor)具有燃料利用率高、可嬗变核废料的优势,是目前较为理想的先进堆型之一。快堆广泛采用池式回路布置,因此对池式快堆(Pool-type Fast Reactor)进行安全分析具有重要意义。本文采用集总参数法建立池式快堆的一回路模型...快堆(Fast Reactor)具有燃料利用率高、可嬗变核废料的优势,是目前较为理想的先进堆型之一。快堆广泛采用池式回路布置,因此对池式快堆(Pool-type Fast Reactor)进行安全分析具有重要意义。本文采用集总参数法建立池式快堆的一回路模型,基于MATLAB编写核热耦合程序并对其进行无保护失流事故工况的安全分析,并将计算结果与实验值及其他机构计算结果进行了对比。结果显示:集总参数法的计算结果与实验和其他机构计算值均符合较好,验证了程序的可靠性。使用该程序可对池式钠冷快堆在无保护失流事故中的堆芯行为与固有安全性做出较为准确的预估计算。展开更多
Some representative working conditions were measured, and the amplitude distribution rule of each representative working condition after analysis of measured data was got. The building of 2 D distributing function be...Some representative working conditions were measured, and the amplitude distribution rule of each representative working condition after analysis of measured data was got. The building of 2 D distributing function between the range and the mean of random load was discussed. Experiment was carried out to get the fatigue strength data of the material of transmission component. Accessing the P S a S m N camber of combined load of bending and torsion on this material after analysis. And the process of calculating the 2 D fatigue life in multi working condition was discussed.展开更多
This report is a summary of China’s climate,as well as major weather and climate events,during 2021.In 2021,the mean temperature in China was 10.5°C,which was 1.0°C above normal(1981–2010 average)and broke...This report is a summary of China’s climate,as well as major weather and climate events,during 2021.In 2021,the mean temperature in China was 10.5°C,which was 1.0°C above normal(1981–2010 average)and broke the highest record since 1951.The annual rainfall in China was 672.1 mm,which was 6.7%above normal.Also,the annual rainfall in northern China was 40.2%above normal,which ranked second highest since 1961.The rainstorm intensity in the rainy season was strong and featured significant extremes,and disasters caused by rainstorms and flooding were more serious than the average in the past decade.In particular,the extremely strong rainstorm in Henan during July and autumn caused flooding in the middle and lower reaches of the Yellow River with severe consequences.Heatwaves occurred more frequently than normal,and their durations in southern China were longer than normal in summer and autumn.Phased drought was obvious,and caused serious impacts in South China.The number of generated and landfalling typhoons was lower than normal;however,Typhoon In-fa broke the record for the longest overland duration,held since 1949,and affected a wide area.Severe convective weather and extreme windy weather occurred frequently,causing serious impacts.The number of cold waves was more than normal,which caused wide-ranging extremely low temperatures in many places.Sandstorms appeared earlier than normal in 2021,and the number of strong dust storm processes was more than normal.展开更多
Transport system is a time-varying, huge and complex system. In order to have the traffic management department make pre-appropriate traffic management measures to adjust the traffic management control program, and re...Transport system is a time-varying, huge and complex system. In order to have the traffic management department make pre-appropriate traffic management measures to adjust the traffic management control program, and release travel information to travelers, to provide optimal path options to ensure that the transport system operates efficiently and safely, we have to monitor the changing of the state of road traffic and to accurately evaluate the state of the traffic, then to predict the future state of traffic. This paper represents the construction of the road traffic flow simulation including the logical structure and the physical structure, and introduces the system functions of forecasting system in Beijing.展开更多
The article is research on the traffic situations of freeways. Different rules make different traffic situations. It is meaningful to research on traffic situations under different conditions. The author analyzes fac...The article is research on the traffic situations of freeways. Different rules make different traffic situations. It is meaningful to research on traffic situations under different conditions. The author analyzes factors like traffic flow and safety, peflbrmance respectively, and proposes the theor3, basis for making more reasonable rules. The author first establishes evaluation system of traffic safety. Then, we compare the freeway network to power network to find a solution. and establish a traffic flow model based on power flow （TFPF）. It calculates power flow. So it applies the formula mode back to the traffic network, chalking up the perforumnce of the traffic condition. We utilize cellular automata （CA） method to simulate traffic circulation, and verify the accuracy of above model with the obtained data.展开更多
An analysis of historical data of Fitzroy River, which lies in the east coast of Australia, reveals that there is an increasing trend in extreme floods and droughts apparently attributable to increased variability of ...An analysis of historical data of Fitzroy River, which lies in the east coast of Australia, reveals that there is an increasing trend in extreme floods and droughts apparently attributable to increased variability of blue and green waters which could be due to climate change. In order to get a better understanding of the impacts of climate change on the water resources of the study area for near future as well as distant future, SWAT （soil and water assessment tool） model was applied. The model is first tested for its suitability in capturing the basin characteristics with available data, and then, forecasts from six GCMs （general circulation model） with about half-a-century lead time to 2046-2064 and about one-century lead time to 2080-2100 are incorporated to evaluate the impacts of climate change under three marker emission scenarios： A2, A1B and B 1. The results showed worsening water resources regime into the future.展开更多
The aim of this study is to investigate whether the comprehensive income （CI） and its individual components are useful in assessing the future cash flows for Italian listed companies. In addition, we verify whether ...The aim of this study is to investigate whether the comprehensive income （CI） and its individual components are useful in assessing the future cash flows for Italian listed companies. In addition, we verify whether the recent requirement of International Accounting Standard （IAS） 1 （r2011） of providing the other comprehensive income （OCI） separates in two sub-totals （recycling and non-recycling items groups） is useful to explain the expected cash flows. We consider a sample of 121 Italian non-financial companies listed on the Italian Stock Exchange for the testing period of 2008-2011, employing a fixed-effect regression model, and we test the relationship between the changes in the variables considered and not the relative absolute value reducing, in this way, the risk of not grasping a report if the independent variable and the response variable do not have the same sign. Our results stress that CI and the two new sub-aggregates are not relevant to explain future cash flows, while net income （NI） and OC1 as a whole seem to be more relevant to make explicit the future financial position. The study contributes, as a sort of post-implementation review, to the current debate on the ability of Cl to predict the future cash flows and on the real usefulness of the CI and the sub-aggregate identified by the IAS 1 revised as well.展开更多
In this paper the flow through a control directional valve is studied by means of a CFD （computational fluid-dynamics） analysis under transient operating conditions. The mesh motion is resolved on a time basis as a ...In this paper the flow through a control directional valve is studied by means of a CFD （computational fluid-dynamics） analysis under transient operating conditions. The mesh motion is resolved on a time basis as a function of the external actuation system In the analysis, an open source fluid-dynamics code is used and both cavitation and turbulence are accounted for in the modeling. Moreover, the numerical model of the working fluid is modified in order to account also for the non-Newtonian fluids. The effects of the shear rate on the shear stress are accounted for both by using experimental measurements and correlations available in literature, such as the Herschel-Bulkley model. The analysis determines the performance of the control directional valve under different operating conditions when using either Newtonian or non-Newtonian fluids. In particular, the discharge coefficient, the recirculating regions, the flow acceleration angle and the pressure and velocity fields are investigated.展开更多
文摘快堆(Fast Reactor)具有燃料利用率高、可嬗变核废料的优势,是目前较为理想的先进堆型之一。快堆广泛采用池式回路布置,因此对池式快堆(Pool-type Fast Reactor)进行安全分析具有重要意义。本文采用集总参数法建立池式快堆的一回路模型,基于MATLAB编写核热耦合程序并对其进行无保护失流事故工况的安全分析,并将计算结果与实验值及其他机构计算结果进行了对比。结果显示:集总参数法的计算结果与实验和其他机构计算值均符合较好,验证了程序的可靠性。使用该程序可对池式钠冷快堆在无保护失流事故中的堆芯行为与固有安全性做出较为准确的预估计算。
文摘Some representative working conditions were measured, and the amplitude distribution rule of each representative working condition after analysis of measured data was got. The building of 2 D distributing function between the range and the mean of random load was discussed. Experiment was carried out to get the fatigue strength data of the material of transmission component. Accessing the P S a S m N camber of combined load of bending and torsion on this material after analysis. And the process of calculating the 2 D fatigue life in multi working condition was discussed.
基金This work was jointly supported by the National Natural Science Foundation of China[grant number 41875120]a National Key Research and Development Project[grant number 2017YFC1502402].
文摘This report is a summary of China’s climate,as well as major weather and climate events,during 2021.In 2021,the mean temperature in China was 10.5°C,which was 1.0°C above normal(1981–2010 average)and broke the highest record since 1951.The annual rainfall in China was 672.1 mm,which was 6.7%above normal.Also,the annual rainfall in northern China was 40.2%above normal,which ranked second highest since 1961.The rainstorm intensity in the rainy season was strong and featured significant extremes,and disasters caused by rainstorms and flooding were more serious than the average in the past decade.In particular,the extremely strong rainstorm in Henan during July and autumn caused flooding in the middle and lower reaches of the Yellow River with severe consequences.Heatwaves occurred more frequently than normal,and their durations in southern China were longer than normal in summer and autumn.Phased drought was obvious,and caused serious impacts in South China.The number of generated and landfalling typhoons was lower than normal;however,Typhoon In-fa broke the record for the longest overland duration,held since 1949,and affected a wide area.Severe convective weather and extreme windy weather occurred frequently,causing serious impacts.The number of cold waves was more than normal,which caused wide-ranging extremely low temperatures in many places.Sandstorms appeared earlier than normal in 2021,and the number of strong dust storm processes was more than normal.
基金Key Projects in Science & Technology Pillar Program in 2007 in Beijing (No.D07020601400705)
文摘Transport system is a time-varying, huge and complex system. In order to have the traffic management department make pre-appropriate traffic management measures to adjust the traffic management control program, and release travel information to travelers, to provide optimal path options to ensure that the transport system operates efficiently and safely, we have to monitor the changing of the state of road traffic and to accurately evaluate the state of the traffic, then to predict the future state of traffic. This paper represents the construction of the road traffic flow simulation including the logical structure and the physical structure, and introduces the system functions of forecasting system in Beijing.
文摘The article is research on the traffic situations of freeways. Different rules make different traffic situations. It is meaningful to research on traffic situations under different conditions. The author analyzes factors like traffic flow and safety, peflbrmance respectively, and proposes the theor3, basis for making more reasonable rules. The author first establishes evaluation system of traffic safety. Then, we compare the freeway network to power network to find a solution. and establish a traffic flow model based on power flow （TFPF）. It calculates power flow. So it applies the formula mode back to the traffic network, chalking up the perforumnce of the traffic condition. We utilize cellular automata （CA） method to simulate traffic circulation, and verify the accuracy of above model with the obtained data.
文摘An analysis of historical data of Fitzroy River, which lies in the east coast of Australia, reveals that there is an increasing trend in extreme floods and droughts apparently attributable to increased variability of blue and green waters which could be due to climate change. In order to get a better understanding of the impacts of climate change on the water resources of the study area for near future as well as distant future, SWAT （soil and water assessment tool） model was applied. The model is first tested for its suitability in capturing the basin characteristics with available data, and then, forecasts from six GCMs （general circulation model） with about half-a-century lead time to 2046-2064 and about one-century lead time to 2080-2100 are incorporated to evaluate the impacts of climate change under three marker emission scenarios： A2, A1B and B 1. The results showed worsening water resources regime into the future.
文摘The aim of this study is to investigate whether the comprehensive income （CI） and its individual components are useful in assessing the future cash flows for Italian listed companies. In addition, we verify whether the recent requirement of International Accounting Standard （IAS） 1 （r2011） of providing the other comprehensive income （OCI） separates in two sub-totals （recycling and non-recycling items groups） is useful to explain the expected cash flows. We consider a sample of 121 Italian non-financial companies listed on the Italian Stock Exchange for the testing period of 2008-2011, employing a fixed-effect regression model, and we test the relationship between the changes in the variables considered and not the relative absolute value reducing, in this way, the risk of not grasping a report if the independent variable and the response variable do not have the same sign. Our results stress that CI and the two new sub-aggregates are not relevant to explain future cash flows, while net income （NI） and OC1 as a whole seem to be more relevant to make explicit the future financial position. The study contributes, as a sort of post-implementation review, to the current debate on the ability of Cl to predict the future cash flows and on the real usefulness of the CI and the sub-aggregate identified by the IAS 1 revised as well.
文摘In this paper the flow through a control directional valve is studied by means of a CFD （computational fluid-dynamics） analysis under transient operating conditions. The mesh motion is resolved on a time basis as a function of the external actuation system In the analysis, an open source fluid-dynamics code is used and both cavitation and turbulence are accounted for in the modeling. Moreover, the numerical model of the working fluid is modified in order to account also for the non-Newtonian fluids. The effects of the shear rate on the shear stress are accounted for both by using experimental measurements and correlations available in literature, such as the Herschel-Bulkley model. The analysis determines the performance of the control directional valve under different operating conditions when using either Newtonian or non-Newtonian fluids. In particular, the discharge coefficient, the recirculating regions, the flow acceleration angle and the pressure and velocity fields are investigated.
