On the basis of introducing relevant theories of Engel's coefficient,this paper analyzes the limitation of these theories in practical application currently in China,for example,continuing to use original theory,n...On the basis of introducing relevant theories of Engel's coefficient,this paper analyzes the limitation of these theories in practical application currently in China,for example,continuing to use original theory,not in line with reality of China;comparison invalidity in length and breadth,is not conducive to relevant analysis;culling out the special factors easily causes distortion of conclusion.Taking rural areas in Hebei Province as an example,this paper analyzes the limitation of Engel's coefficient in analyzing the gap of rural economy:in terms of region horizontally,Engel's coefficient neglects the difference of consumption structure among regions,and difference of economic stages among regions;in terms of time vertically,Engel's coefficient neglects the periodic change of consumption structure and the ratio change of different families in different periods.According to the reality of China's rural areas,the correction model of Engel's coefficient is established as follows.Firstly,Engel's coefficient=Percentage of expenditure variation(food+ education+ medical service) /Percentage of total expenditure variation;Engel's coefficient=Percentage of expenditure variation(food+ education+ medical service) /Percentage of income variation.Secondly,Engel's coefficient=Percentage of expenditure variation of food/Percentage of variation of(total expenditure educational expenditure-medical expenditure.Thirdly,Engel's coefficient=Percentage of expenditure variation of food/Percentage of total expenditure variation.展开更多
It is meaningful to study trends in food and education expenditure as proportions of total household expenditure.In this study,based on year 2006 to 2017 data from Heilongjiang province in China and Ontario province i...It is meaningful to study trends in food and education expenditure as proportions of total household expenditure.In this study,based on year 2006 to 2017 data from Heilongjiang province in China and Ontario province in Canada,a linear regression model is used to forecast the Engel’s coefficients(proportion spent on food)and the education proportion from year 2018 to 2027 for those two regions.The results suggest that in both regions the Engel’s coefficients show a decreasing trend,while the education expenditure proportions show an increasing trend.The ratios of education expenditure to food expenditure in both places show an increasing trend.展开更多
The influence of density,foliage and stem flexibility on the roughness coefficients under unsubmerged conditions,such as Manning's n,is investigated experimentally.An instrumentation system has been developed for mea...The influence of density,foliage and stem flexibility on the roughness coefficients under unsubmerged conditions,such as Manning's n,is investigated experimentally.An instrumentation system has been developed for measuring the flow rate ranging from 0.1 to 0.3 L/s under the condition of different artificial foliated reeds.Based on the experimental results,the influence on the relationship between n with different density,foliage,flexibility and flow depth is discussed.It is found that the foliage and the density are the important factors affecting Manning's n.At a range of relatively low velocity and relatively large bending stiffness of stem,Manning's n is not influenced significanthy by the flexibility of stem.展开更多
Based on isotropie linear poroelastic theory and under the undrained condition, we summarize three equations connecting the Skempton's coefficient B with the groundwater level. After analysis, we propose a method to ...Based on isotropie linear poroelastic theory and under the undrained condition, we summarize three equations connecting the Skempton's coefficient B with the groundwater level. After analysis, we propose a method to calculate the Skempton's coefficient B according to the relationship between water level and tidal strain. With this method we can get the value of B without the earthquake occurrence, which can provide the high frequency waves for research. Besides, we can also get the in-suit Skempton's coefficient B without the experiment of rock physics. In addition, we analyze the observed data of Changping station recorded in groundwater monitoring network (abv., GMN) before and after the Wenchuan Ms8.0 with this method, and find out there's a slight change of the value of B after the seismic waves passed by, which implies that the propagation of seismic waves may have brought some variations to the poroelastic medium of the well.展开更多
Green's functions for Blot's dynamic equation in the frequency domain can be a highly useful tool for the investigation of dynamic responses of a saturated porous medium. Its applications are found in soil dynamics,...Green's functions for Blot's dynamic equation in the frequency domain can be a highly useful tool for the investigation of dynamic responses of a saturated porous medium. Its applications are found in soil dynamics, seismology, earthquake engineering, rock mechanics, geophysics, and acoustics. However, the mathematical work for deriving it can be daunting. Green's functions have been presented utilizing an analogy between the dynamic thermoelasticity and the dynamic poroelasticity in the frequency domain using the u-p formulation. In this work, a special term "decoupling coefficient" for the decomposition of the fast and slow dilatational waves is proposed and expressed to present a new methodology for deriving the poroelastodynamic Green's functions. The correct- ness of the solution is demonstrated by numerically comparing the current solution with Cheng's previous solution. The separation of the two waves in the present methodology allows the more accurate evaluation of Green's functions, particularly the solution of the slow dilatational wave. This can be advantageous for the numerical implementation of the boundary element method (BEM) and other applications.展开更多
A real-time channel flood forecast model was developed to simulate channel flow in plain rivers based on the dynamic wave theory. Taking into consideration channel shape differences along the channel, a roughness upda...A real-time channel flood forecast model was developed to simulate channel flow in plain rivers based on the dynamic wave theory. Taking into consideration channel shape differences along the channel, a roughness updating technique was developed using the Kalman filter method to update Manning's roughness coefficient at each time step of the calculation processes. Channel shapes were simplified as rectangles, triangles, and parabolas, and the relationships between hydraulic radius and water depth were developed for plain rivers. Based on the relationship between the Froude number and the inertia terms of the momentum equation in the Saint-Venant equations, the relationship between Manning's roughness coefficient and water depth was obtained. Using the channel of the Huaihe River from Wangjiaba to Lutaizi stations as a case, to test the performance and rationality of the present flood routing model, the original hydraulic model was compared with the developed model. Results show that the stage hydrographs calculated by the developed flood routing model with the updated Manning's roughness coefficient have a good agreement with the observed stage hydrographs. This model performs better than the original hydraulic model.展开更多
By employing the information-reshufflingmethod that integrates census data, precipitation dataand inquiry data of water consumption, this paperdiscusses 5 (water consumption coefficient of people’sliving) in allusion...By employing the information-reshufflingmethod that integrates census data, precipitation dataand inquiry data of water consumption, this paperdiscusses 5 (water consumption coefficient of people’sliving) in allusion to different precipitation zones anddifferent periods of time. The study shows that 5-(water consumption coefficient of urban people’sliving), 5. (water consumption coefficient of ruralpeople’s living) and increase with time passing, andthe increasing extent of 5 is 1.84, 2.62, 2.84 and 2.68times respectively from the west to the east, whichresults from the total quantity of water resources andthe speed of urbanization. 5- and 5. of eachprecipitation zone increased with 5- increasing morequickly than 5., and the difference between the twoalso increased when time passed. In the past fifty years(1950-2000), the increasing extent of 5- was 1.71,2.96, 2.41 and 2.33 times respectively from the westto the east, in which 200-400mm precipitation zoneincreased more than others. Meanwhile the increasingextent of 5. is 1.55, 1.60, 1.53 and 1.64 timesrespectively from the west to the east with eachprecipitation zone increasing similarly. The change of5-is due to the speed of urbanization and the stabilityof water resources. This study provides basis forcalculating the water demand of people’s living andrevealing the impact of water demand of people’s livingon ecological drought in different zones.展开更多
This paper proposes a new method to reduce the dimensionality of input and output spaces in DEA models. The method is based on Yanai’s Generalized Coefficient of Determination and on the concept of pseudo-rank of a m...This paper proposes a new method to reduce the dimensionality of input and output spaces in DEA models. The method is based on Yanai’s Generalized Coefficient of Determination and on the concept of pseudo-rank of a matrix. In addition, the paper suggests a rule to determine the cardinality of the subset of selected variables in a way to gain the maximal discretionary power and to suffer a minimal informational loss.展开更多
In this paper we present a graphical method for decision of restitution coefficient based on ODE. To simulate and illustrate our proposed method and efficient characteristics that demonstrate for two colliding bodies ...In this paper we present a graphical method for decision of restitution coefficient based on ODE. To simulate and illustrate our proposed method and efficient characteristics that demonstrate for two colliding bodies we used MatLab. In simulation to approach to the real case we used an assumption of additional virtual body’s position and velocity for characterizing material of the body which is involved to express the restitution coefficient. The graphic animation program is developed based on ODE for the computer simulation of the proposed graphical method. Additionally, we determined this new characteristic for some sport game balls such as basketball, volleyball, etc.展开更多
A new method for analysis of counter beams is presented in the paper. The analysis has taken into account their stiffness EI, Winkler’s space with modulus of subgrade reaction k and equality deformities of the founda...A new method for analysis of counter beams is presented in the paper. The analysis has taken into account their stiffness EI, Winkler’s space with modulus of subgrade reaction k and equality deformities of the foundation beam with the ground. The solution is found by using the numerical analysis of the Winkler’s model, with variation of different moduli of the subgrade reaction k2 outside the force zone r, while under the force P exists the modulus of the subgrade reaction k, up to the definition of minimum bending moments. The exponential function k2(r), as the geometric position of the minimum moments is approximately assumed. From the potential energy conditions of the reciprocity of displacement and reaction, the width of the zone r and the modulus of the subgrade reaction k2 are explicitly determined, introducing in the calculation initial and calculation soil displacement wsi successively. At the end of the paper, it presented numerical example in which the influence of k and k2 values on bending moments of the counter beam is analyzed. The essential idea of this paper is to decrease the quantity of the reinforcement in the foundations, beams, i.e. to obtain a cost-efficient foundation construction.展开更多
Retail sales of consumer goods nationwide totaled RMB 38.1 trillion in 2018,an increase of nine percent year-on-year,said Gao Feng,spokesman for the Ministry of Commerce,recently.As a result,consumer spending contribu...Retail sales of consumer goods nationwide totaled RMB 38.1 trillion in 2018,an increase of nine percent year-on-year,said Gao Feng,spokesman for the Ministry of Commerce,recently.As a result,consumer spending contributed 76.2 percent to economic growth,18.6 percentage points higher than 2017,and consumption remained the top engine driving China’s economy.展开更多
文摘On the basis of introducing relevant theories of Engel's coefficient,this paper analyzes the limitation of these theories in practical application currently in China,for example,continuing to use original theory,not in line with reality of China;comparison invalidity in length and breadth,is not conducive to relevant analysis;culling out the special factors easily causes distortion of conclusion.Taking rural areas in Hebei Province as an example,this paper analyzes the limitation of Engel's coefficient in analyzing the gap of rural economy:in terms of region horizontally,Engel's coefficient neglects the difference of consumption structure among regions,and difference of economic stages among regions;in terms of time vertically,Engel's coefficient neglects the periodic change of consumption structure and the ratio change of different families in different periods.According to the reality of China's rural areas,the correction model of Engel's coefficient is established as follows.Firstly,Engel's coefficient=Percentage of expenditure variation(food+ education+ medical service) /Percentage of total expenditure variation;Engel's coefficient=Percentage of expenditure variation(food+ education+ medical service) /Percentage of income variation.Secondly,Engel's coefficient=Percentage of expenditure variation of food/Percentage of variation of(total expenditure educational expenditure-medical expenditure.Thirdly,Engel's coefficient=Percentage of expenditure variation of food/Percentage of total expenditure variation.
文摘It is meaningful to study trends in food and education expenditure as proportions of total household expenditure.In this study,based on year 2006 to 2017 data from Heilongjiang province in China and Ontario province in Canada,a linear regression model is used to forecast the Engel’s coefficients(proportion spent on food)and the education proportion from year 2018 to 2027 for those two regions.The results suggest that in both regions the Engel’s coefficients show a decreasing trend,while the education expenditure proportions show an increasing trend.The ratios of education expenditure to food expenditure in both places show an increasing trend.
基金The Public Science and Technology Research Funds Projects of Ocean under contract Nos 200905001 and 201005019UNESCO-IHE Partnership Research Fund (UPaRF) under contract No.60038881the National Natural Science Foundation of China under contract No.50939003
文摘The influence of density,foliage and stem flexibility on the roughness coefficients under unsubmerged conditions,such as Manning's n,is investigated experimentally.An instrumentation system has been developed for measuring the flow rate ranging from 0.1 to 0.3 L/s under the condition of different artificial foliated reeds.Based on the experimental results,the influence on the relationship between n with different density,foliage,flexibility and flow depth is discussed.It is found that the foliage and the density are the important factors affecting Manning's n.At a range of relatively low velocity and relatively large bending stiffness of stem,Manning's n is not influenced significanthy by the flexibility of stem.
基金supported by National Natural Science Foundation of China(40674024 and 40374019)
文摘Based on isotropie linear poroelastic theory and under the undrained condition, we summarize three equations connecting the Skempton's coefficient B with the groundwater level. After analysis, we propose a method to calculate the Skempton's coefficient B according to the relationship between water level and tidal strain. With this method we can get the value of B without the earthquake occurrence, which can provide the high frequency waves for research. Besides, we can also get the in-suit Skempton's coefficient B without the experiment of rock physics. In addition, we analyze the observed data of Changping station recorded in groundwater monitoring network (abv., GMN) before and after the Wenchuan Ms8.0 with this method, and find out there's a slight change of the value of B after the seismic waves passed by, which implies that the propagation of seismic waves may have brought some variations to the poroelastic medium of the well.
基金Project supported by the National Natural Science Foundation of China(Nos.51478435,11402150,and 11172268)
文摘Green's functions for Blot's dynamic equation in the frequency domain can be a highly useful tool for the investigation of dynamic responses of a saturated porous medium. Its applications are found in soil dynamics, seismology, earthquake engineering, rock mechanics, geophysics, and acoustics. However, the mathematical work for deriving it can be daunting. Green's functions have been presented utilizing an analogy between the dynamic thermoelasticity and the dynamic poroelasticity in the frequency domain using the u-p formulation. In this work, a special term "decoupling coefficient" for the decomposition of the fast and slow dilatational waves is proposed and expressed to present a new methodology for deriving the poroelastodynamic Green's functions. The correct- ness of the solution is demonstrated by numerically comparing the current solution with Cheng's previous solution. The separation of the two waves in the present methodology allows the more accurate evaluation of Green's functions, particularly the solution of the slow dilatational wave. This can be advantageous for the numerical implementation of the boundary element method (BEM) and other applications.
基金supported by the Special Fund for Public Welfare (Meteorology) of China (Grants No. GYHY201006037 and GYHY200906007)
文摘A real-time channel flood forecast model was developed to simulate channel flow in plain rivers based on the dynamic wave theory. Taking into consideration channel shape differences along the channel, a roughness updating technique was developed using the Kalman filter method to update Manning's roughness coefficient at each time step of the calculation processes. Channel shapes were simplified as rectangles, triangles, and parabolas, and the relationships between hydraulic radius and water depth were developed for plain rivers. Based on the relationship between the Froude number and the inertia terms of the momentum equation in the Saint-Venant equations, the relationship between Manning's roughness coefficient and water depth was obtained. Using the channel of the Huaihe River from Wangjiaba to Lutaizi stations as a case, to test the performance and rationality of the present flood routing model, the original hydraulic model was compared with the developed model. Results show that the stage hydrographs calculated by the developed flood routing model with the updated Manning's roughness coefficient have a good agreement with the observed stage hydrographs. This model performs better than the original hydraulic model.
文摘By employing the information-reshufflingmethod that integrates census data, precipitation dataand inquiry data of water consumption, this paperdiscusses 5 (water consumption coefficient of people’sliving) in allusion to different precipitation zones anddifferent periods of time. The study shows that 5-(water consumption coefficient of urban people’sliving), 5. (water consumption coefficient of ruralpeople’s living) and increase with time passing, andthe increasing extent of 5 is 1.84, 2.62, 2.84 and 2.68times respectively from the west to the east, whichresults from the total quantity of water resources andthe speed of urbanization. 5- and 5. of eachprecipitation zone increased with 5- increasing morequickly than 5., and the difference between the twoalso increased when time passed. In the past fifty years(1950-2000), the increasing extent of 5- was 1.71,2.96, 2.41 and 2.33 times respectively from the westto the east, in which 200-400mm precipitation zoneincreased more than others. Meanwhile the increasingextent of 5. is 1.55, 1.60, 1.53 and 1.64 timesrespectively from the west to the east with eachprecipitation zone increasing similarly. The change of5-is due to the speed of urbanization and the stabilityof water resources. This study provides basis forcalculating the water demand of people’s living andrevealing the impact of water demand of people’s livingon ecological drought in different zones.
基金Supported by the National Natural Science Foundation of China (No.20476059, No.20276037) and 863 Hi-Technology Re-search and Development Program of China (2004 AA616040).
文摘This paper proposes a new method to reduce the dimensionality of input and output spaces in DEA models. The method is based on Yanai’s Generalized Coefficient of Determination and on the concept of pseudo-rank of a matrix. In addition, the paper suggests a rule to determine the cardinality of the subset of selected variables in a way to gain the maximal discretionary power and to suffer a minimal informational loss.
文摘In this paper we present a graphical method for decision of restitution coefficient based on ODE. To simulate and illustrate our proposed method and efficient characteristics that demonstrate for two colliding bodies we used MatLab. In simulation to approach to the real case we used an assumption of additional virtual body’s position and velocity for characterizing material of the body which is involved to express the restitution coefficient. The graphic animation program is developed based on ODE for the computer simulation of the proposed graphical method. Additionally, we determined this new characteristic for some sport game balls such as basketball, volleyball, etc.
文摘A new method for analysis of counter beams is presented in the paper. The analysis has taken into account their stiffness EI, Winkler’s space with modulus of subgrade reaction k and equality deformities of the foundation beam with the ground. The solution is found by using the numerical analysis of the Winkler’s model, with variation of different moduli of the subgrade reaction k2 outside the force zone r, while under the force P exists the modulus of the subgrade reaction k, up to the definition of minimum bending moments. The exponential function k2(r), as the geometric position of the minimum moments is approximately assumed. From the potential energy conditions of the reciprocity of displacement and reaction, the width of the zone r and the modulus of the subgrade reaction k2 are explicitly determined, introducing in the calculation initial and calculation soil displacement wsi successively. At the end of the paper, it presented numerical example in which the influence of k and k2 values on bending moments of the counter beam is analyzed. The essential idea of this paper is to decrease the quantity of the reinforcement in the foundations, beams, i.e. to obtain a cost-efficient foundation construction.
文摘Retail sales of consumer goods nationwide totaled RMB 38.1 trillion in 2018,an increase of nine percent year-on-year,said Gao Feng,spokesman for the Ministry of Commerce,recently.As a result,consumer spending contributed 76.2 percent to economic growth,18.6 percentage points higher than 2017,and consumption remained the top engine driving China’s economy.