Branch length and branch diameter are important characteristics that determine wood quality and yield.Development of static branch length and diameter models by incorporating individual tree variables,site quality and...Branch length and branch diameter are important characteristics that determine wood quality and yield.Development of static branch length and diameter models by incorporating individual tree variables,site quality and competition have been widely studied,while the climate effect has rarely been reported.In this study,mixed-effects climate-sensitive branch length and diameter models were developed based on 228 sample trees of Larix kaempferi from three latitude regions in China(approximate 42°N in Liaoning Province,33°N in Gansu Province,and 30°N in Hubei Province).Results revealed that diameter at breast height,and crown ratio,sum of the basal areas of trees larger than the subject trees,dominant tree height,mean warmest month temperature,and summer precipitation substantially improved branch length model.Diameter at breast height,and crown ratio,ratio of the sum of DBH in sample plot to the subject tree,dominant tree height,mean warmest month temperature,and spring precipitation significantly improved branch diameter model.Compared with base model,mean square error reduction of mixed-effects branch length and diameter models were 32.9%and 44.1%,respectively.The relative contributions of covariates to branch length model were tree size(59.1%),site quality(25.7%),competition(13.5%),and climate(1.7%),and branch diameter model were tree size(57.0%),competition(21.9%),site quality(18.3%),and climate(2.8%).Relative contributions of covariates on branch length and diameter models from different latitude regions were different.Effects of competition on branch length model in Liaoning and Hubei were larger than climate,whereas climate in Gansu was larger than competition.As for branch diameter model,competition in Liaoning was larger than site quality,whereas site quality in Hubei and Gansu was larger than competition.The present study strengthened the importance of considering climate variables in developing branch length and diameter model.It is desirable to disentangle the different sources of variations in affecting branch length and diameter from different latitude regions to reduce the uncertainty in predicting branch characteristics under the condition of climate changing.展开更多
A vertical (laterally averaged) two-dimensional hydrodynamic model is developed for tides, tidal current, and salinity in a branched estuarine system. The governing equations are solved with the hydrostatic pressure d...A vertical (laterally averaged) two-dimensional hydrodynamic model is developed for tides, tidal current, and salinity in a branched estuarine system. The governing equations are solved with the hydrostatic pressure distribution assumption and the Boussinesq approximation. An explicit scheme is employed to solve the continuity equations. The momentum and mass balance equations are solved implicitly in the Cartesian coordinate system. The tributaries are governed by the same dynamic equations. A control volume at the junctions is designed to conserve mass and volume transport in the finite difference schemes, based on the physical principle of continuum medium of fluid. Predictions by the developed model are compared with the analytic solutions of steady wind-driven circulatory flow and tidal flow. The model results for the velocities and water surface elevations coincide with analytic results. The model is then applied to the Tanshui River estuarine system. Detailed model calibration and verification have been conducted with measured water surface elevations, tidal current, and salinity distributions. The overall performance of the model is in qualitative agreement with the available field data. The calibrated and verified numerical model has been used to quantify the tidal prism and flushing rate in the Tanshui River-Tahan Stream, Hsintien Stream, and Keelung River.展开更多
A branched model was established to reproduce the vehicle creeping status and illustrate the mechanism for severe rattle phenomena of a 5-speed manual transmission in this paper.Firstly,a quasi-transient engine model ...A branched model was established to reproduce the vehicle creeping status and illustrate the mechanism for severe rattle phenomena of a 5-speed manual transmission in this paper.Firstly,a quasi-transient engine model was founded and the effective output torque with the crankshaft angle changing was achieved.Then,the time-varying stiffness of loaded gear pairs was obtained,which was calculated by both bending and shearing deformation stiffnesses through finite element result regression analysis and the contact deformation stiffness through the empirical formula.Finally,the branched model of powertrain system considering LuG re tire property and differential characteristics was established to predict the vehicle creeping status and rattle phenomenon of unloaded gear pairs in consideration of detailed drag torque model,and it would make a solid theoretical basis for further research on gear rattle mechanism and vehicle experiments.展开更多
The multi-branched Husimi recursive lattice is extended to a virtual structure with fractional numbers of branches joined on one site. Although the lattice is undrawable in real space, the concept is consistent with r...The multi-branched Husimi recursive lattice is extended to a virtual structure with fractional numbers of branches joined on one site. Although the lattice is undrawable in real space, the concept is consistent with regular Husimi lattice. The Ising spins of antiferromagnetic interaction on such a set of lattices are calculated to check the critical temperatures(Tc) and ideal glass transition temperatures(Tk) variation with fractional branch numbers. Besides the similar results of two solutions representing the stable state(crystal) and metastable state(supercooled liquid)and indicating the phase transition temperatures, the phase transitions show a well-defined shift with branch number variation. Therefore the fractional branch number as a parameter can be used as an adjusting tool in constructing a recursive lattice model to describe real systems.展开更多
The Rouse-Zimm model with slippage was improved and the basic parameters of modelwere modified to explain the rheological properties of star-type branched polymersolutions. The theoretical results show good agreement ...The Rouse-Zimm model with slippage was improved and the basic parameters of modelwere modified to explain the rheological properties of star-type branched polymersolutions. The theoretical results show good agreement with experimental data.展开更多
This research was conducted on the Damietta branch of the Nile River, Egypt. The Damietta branch receives pollution loadings from the Omar-Bek drain and two power stations located along the path of the branch. The mai...This research was conducted on the Damietta branch of the Nile River, Egypt. The Damietta branch receives pollution loadings from the Omar-Bek drain and two power stations located along the path of the branch. The main objective of this research consisted of comparing between the Damietta branch water quality before and after the Ethiopian Dam is built. This comparison was conducted by using the river pollutant (RP) modeling. First, the actual data and the modeling results were compared in order to prove the efficiency and validity of the RP modeling. Findings from regression analysis yielded a strong positive linear relationship (r = 0.987) between the two results. The modeling results showed that Omar-Bek drain had less impact on the Damietta branch water quality. The results also showed that the effluent discharge from the two power stations affected water quality and aquatic life because large quantities of warm and polluted water discharged back into the Damietta branch. The results also showed that constructing the Ethiopian Renaissance Dam would slightly increase pollutants concentrations in the Damietta branch and that this increase would cause a slight deterioration in water quality.展开更多
In this paper, a new branch-and-bound algorithm based on the Lagrangian dual relaxation and continuous relaxation is proposed for discrete multi-factor portfolio selection model with roundlot restriction in financial ...In this paper, a new branch-and-bound algorithm based on the Lagrangian dual relaxation and continuous relaxation is proposed for discrete multi-factor portfolio selection model with roundlot restriction in financial optimization. This discrete portfolio model is of integer quadratic programming problems. The separable structure of the model is investigated by using Lagrangian relaxation and dual search. Computational results show that the algorithm is capable of solving real-world portfolio problems with data from US stock market and randomly generated test problems with up to 120 securities.展开更多
Korean larch(Larix olgensis)is one of the main tree species for aff orestation and timber production in northeast China.However,its timber quality and growth ability are largely infl uenced by crown size,structure and...Korean larch(Larix olgensis)is one of the main tree species for aff orestation and timber production in northeast China.However,its timber quality and growth ability are largely infl uenced by crown size,structure and shape.The majority of crown models are static models based on tree size and stand characteristics from temporary sample plots,but crown dynamic models has seldom been constructed.Therefore,this study aimed to develop height to crown base(HCB)and crown length(CL)dynamic models using the branch mortality technique for a Korean larch plantation.The nonlinear mixed-eff ects model with random eff ects,variance functions and correlation structures,was used to build HCB and CL dynamic models.The data were obtained from 95 sample trees of 19 plots in Meng JiaGang forest farm in Northeast China.The results showed that HCB progressively increases as tree age,tree height growth(HT growth)and diameter at breast height growth(DBH growth).The CL was increased with tree age in 20 years ago,and subsequently stabilized.HT growth,DBH growth stand basal area(BAS)and crown competition factor(CCF)signifi cantly infl uenced HCB and CL.The HCB was positively correlated with BAS,HT growth and DBH growth,but negatively correlated with CCF.The CL was positively correlated with BAS and CCF,but negatively correlated with DBH growth.Model fi tting and validation confi rmed that the mixed-eff ects model considering the stand and tree level random eff ects was accurate and reliable for predicting the HCB and CL dynamics.However,the models involving adding variance functions and time series correlation structure could not completely remove heterogeneity and autocorrelation,and the fi tting precision of the models was reduced.Therefore,from the point of view of application,we should take care to avoid setting up over-complex models.The HCB and CL dynamic models in our study may also be incorporated into stand growth and yield model systems in China.展开更多
The integration and development of grass-roots Party organizations and accurate poverty alleviation is the focus in social development in the new period. This is also a new measure explored by the CPC Central Committe...The integration and development of grass-roots Party organizations and accurate poverty alleviation is the focus in social development in the new period. This is also a new measure explored by the CPC Central Committee in the new historical period to solve rural reform and extricate the poor from poverty,and can effectively enhance the enthusiasm of the masses in poverty alleviation and development work. Xundian Hui and Yi Autonomous County is located in the mountainous area of northeast Yunnan Province. It is one of the 592 national key counties for poverty alleviation and development and one of the 38 continuous development counties in Wumeng Mountain area. Since the implementation of the accurate poverty alleviation strategy,Xundian County insists on getting rid of poverty to grasp the overall situation of county economic and social development,focus on the actual situation of the county people,and conscientiously grasp the key of industrial poverty alleviation. It regards industry as the fundamental driving force to realize poverty alleviation from " blood transfusion" to " blood creation",and innovates the model of " Party branch +" to help the poor out of poverty by industry. It has selected 187 agricultural enterprises( cooperatives,large households) to achieve full coverage of all registered poor households,and achieved remarkable results. It has realized that each poor village has one to two leading industries,and each poor household has one to two industrial income projects,having led 30 500 poor households to increase their average income by more than 1 850 yuan. The final incidence of poverty decreased from 26. 93% in 2014 to 0. 35% at the end of 2017,becoming one of the first counties in Yunnan Province to get rid of poverty. It is also the only county in Yunnan Province that has won the Antipoverty Organization Innovation Award of the State Council. Based on field research and interviews,this paper analyzes and summarizes the specific methods,main achievements,practical experience and popularization and application measures of Xundian County " Party Branch +" to promote industrial poverty alleviation,so as to provide necessary reference for accurate poverty reduction and poverty alleviation in similar mountainous areas of Yunnan Province and other provinces.展开更多
A 0-1 integer programming model for weekly fleet assignment was put forward based on linear network and weekly flight scheduling in China. In this model, the objective function is to maximize the total profit of fleet...A 0-1 integer programming model for weekly fleet assignment was put forward based on linear network and weekly flight scheduling in China. In this model, the objective function is to maximize the total profit of fleet assignment, subject to the constraints of coverage, aircraft flow balance, fleet size, aircraft availability, aircraft usage, flight restriction, aircraft seat capacity, and stopover. Then the branch-and-bound algorithm based on special ordered set was applied to solve the model. At last, a real- wofld case study on an airline with 5 fleets, 48 aircrafts and 1 786 flight legs indicated that the profit increase was ￥ 1 591276 one week and the running time was no more than 4 rain, which shows that the model and algorithm are fairly good for domestic airline.展开更多
Mantle branch structure is the third tectonic unit of multiple evolution of a mantle branch. It is not only the main mechanism of intercontinental orogeny, but also an important ore-forming and ore-control structure. ...Mantle branch structure is the third tectonic unit of multiple evolution of a mantle branch. It is not only the main mechanism of intercontinental orogeny, but also an important ore-forming and ore-control structure. Studies on geotectonic evolution, regional geological characteristics and oreforming and ore-control structures have shown that since the Mesozoic the Da Hinggan Mts. region has entered a typical intercontinental orogenic stage, and it is closely related to mantle branch activities. The south-central segment of the Da Hinggan Mts. is a typical mantle branch structure and possesses obvious magmatic-metamorphic complexes in the core, detachment slip beds in the periphery and overlapped fault depression basins. Moreover, all of these are the principal factors leading to ore formation and ore control in the region. This paper also further explores the mechanism of mineralization in the south-central segment of the Da Hinggan, summaries the rules of mineralization, puts forward the models of mineralization and points out future ore-exploring orientation.展开更多
We consider a population-size-dependent branching chain in a general random environment.We give suffcident conditions for certain extinction and for non-certain extinction.The chain exhibits different asymptotic accor...We consider a population-size-dependent branching chain in a general random environment.We give suffcident conditions for certain extinction and for non-certain extinction.The chain exhibits different asymptotic according to supk,θmk,θ1, mk,θn→1 as k →∞, n→∞, infk,θmk,θ1.展开更多
基金funded by the National Key Research and Development Program of China(2023YFD2200801)National Natural Science Foundation of China(No.32471864)+1 种基金the Science&Technology Project for Excellent Young Scholars of Liaoning Province(2024JH3/10200036)Liao Ning Revitalization Talents Program(No.XLYC2403180).
文摘Branch length and branch diameter are important characteristics that determine wood quality and yield.Development of static branch length and diameter models by incorporating individual tree variables,site quality and competition have been widely studied,while the climate effect has rarely been reported.In this study,mixed-effects climate-sensitive branch length and diameter models were developed based on 228 sample trees of Larix kaempferi from three latitude regions in China(approximate 42°N in Liaoning Province,33°N in Gansu Province,and 30°N in Hubei Province).Results revealed that diameter at breast height,and crown ratio,sum of the basal areas of trees larger than the subject trees,dominant tree height,mean warmest month temperature,and summer precipitation substantially improved branch length model.Diameter at breast height,and crown ratio,ratio of the sum of DBH in sample plot to the subject tree,dominant tree height,mean warmest month temperature,and spring precipitation significantly improved branch diameter model.Compared with base model,mean square error reduction of mixed-effects branch length and diameter models were 32.9%and 44.1%,respectively.The relative contributions of covariates to branch length model were tree size(59.1%),site quality(25.7%),competition(13.5%),and climate(1.7%),and branch diameter model were tree size(57.0%),competition(21.9%),site quality(18.3%),and climate(2.8%).Relative contributions of covariates on branch length and diameter models from different latitude regions were different.Effects of competition on branch length model in Liaoning and Hubei were larger than climate,whereas climate in Gansu was larger than competition.As for branch diameter model,competition in Liaoning was larger than site quality,whereas site quality in Hubei and Gansu was larger than competition.The present study strengthened the importance of considering climate variables in developing branch length and diameter model.It is desirable to disentangle the different sources of variations in affecting branch length and diameter from different latitude regions to reduce the uncertainty in predicting branch characteristics under the condition of climate changing.
基金theScienceCouncil,Taiwan(GrantNo.NSC92 2211 E 037and92 2211 E 057)
文摘A vertical (laterally averaged) two-dimensional hydrodynamic model is developed for tides, tidal current, and salinity in a branched estuarine system. The governing equations are solved with the hydrostatic pressure distribution assumption and the Boussinesq approximation. An explicit scheme is employed to solve the continuity equations. The momentum and mass balance equations are solved implicitly in the Cartesian coordinate system. The tributaries are governed by the same dynamic equations. A control volume at the junctions is designed to conserve mass and volume transport in the finite difference schemes, based on the physical principle of continuum medium of fluid. Predictions by the developed model are compared with the analytic solutions of steady wind-driven circulatory flow and tidal flow. The model results for the velocities and water surface elevations coincide with analytic results. The model is then applied to the Tanshui River estuarine system. Detailed model calibration and verification have been conducted with measured water surface elevations, tidal current, and salinity distributions. The overall performance of the model is in qualitative agreement with the available field data. The calibrated and verified numerical model has been used to quantify the tidal prism and flushing rate in the Tanshui River-Tahan Stream, Hsintien Stream, and Keelung River.
基金National Natural Science Foundations of China(Nos.51175379,51575393)
文摘A branched model was established to reproduce the vehicle creeping status and illustrate the mechanism for severe rattle phenomena of a 5-speed manual transmission in this paper.Firstly,a quasi-transient engine model was founded and the effective output torque with the crankshaft angle changing was achieved.Then,the time-varying stiffness of loaded gear pairs was obtained,which was calculated by both bending and shearing deformation stiffnesses through finite element result regression analysis and the contact deformation stiffness through the empirical formula.Finally,the branched model of powertrain system considering LuG re tire property and differential characteristics was established to predict the vehicle creeping status and rattle phenomenon of unloaded gear pairs in consideration of detailed drag torque model,and it would make a solid theoretical basis for further research on gear rattle mechanism and vehicle experiments.
文摘The multi-branched Husimi recursive lattice is extended to a virtual structure with fractional numbers of branches joined on one site. Although the lattice is undrawable in real space, the concept is consistent with regular Husimi lattice. The Ising spins of antiferromagnetic interaction on such a set of lattices are calculated to check the critical temperatures(Tc) and ideal glass transition temperatures(Tk) variation with fractional branch numbers. Besides the similar results of two solutions representing the stable state(crystal) and metastable state(supercooled liquid)and indicating the phase transition temperatures, the phase transitions show a well-defined shift with branch number variation. Therefore the fractional branch number as a parameter can be used as an adjusting tool in constructing a recursive lattice model to describe real systems.
文摘The Rouse-Zimm model with slippage was improved and the basic parameters of modelwere modified to explain the rheological properties of star-type branched polymersolutions. The theoretical results show good agreement with experimental data.
文摘This research was conducted on the Damietta branch of the Nile River, Egypt. The Damietta branch receives pollution loadings from the Omar-Bek drain and two power stations located along the path of the branch. The main objective of this research consisted of comparing between the Damietta branch water quality before and after the Ethiopian Dam is built. This comparison was conducted by using the river pollutant (RP) modeling. First, the actual data and the modeling results were compared in order to prove the efficiency and validity of the RP modeling. Findings from regression analysis yielded a strong positive linear relationship (r = 0.987) between the two results. The modeling results showed that Omar-Bek drain had less impact on the Damietta branch water quality. The results also showed that the effluent discharge from the two power stations affected water quality and aquatic life because large quantities of warm and polluted water discharged back into the Damietta branch. The results also showed that constructing the Ethiopian Renaissance Dam would slightly increase pollutants concentrations in the Damietta branch and that this increase would cause a slight deterioration in water quality.
基金Project supported by the National Natural Science Foundation of China （Grant Nos.70518001. 70671064）
文摘In this paper, a new branch-and-bound algorithm based on the Lagrangian dual relaxation and continuous relaxation is proposed for discrete multi-factor portfolio selection model with roundlot restriction in financial optimization. This discrete portfolio model is of integer quadratic programming problems. The separable structure of the model is investigated by using Lagrangian relaxation and dual search. Computational results show that the algorithm is capable of solving real-world portfolio problems with data from US stock market and randomly generated test problems with up to 120 securities.
基金supported by the National Key Research and Development Program of China(2017YFD0600401)the Fundamental Research Funds for the Central Universities(2572019CP08)
文摘Korean larch(Larix olgensis)is one of the main tree species for aff orestation and timber production in northeast China.However,its timber quality and growth ability are largely infl uenced by crown size,structure and shape.The majority of crown models are static models based on tree size and stand characteristics from temporary sample plots,but crown dynamic models has seldom been constructed.Therefore,this study aimed to develop height to crown base(HCB)and crown length(CL)dynamic models using the branch mortality technique for a Korean larch plantation.The nonlinear mixed-eff ects model with random eff ects,variance functions and correlation structures,was used to build HCB and CL dynamic models.The data were obtained from 95 sample trees of 19 plots in Meng JiaGang forest farm in Northeast China.The results showed that HCB progressively increases as tree age,tree height growth(HT growth)and diameter at breast height growth(DBH growth).The CL was increased with tree age in 20 years ago,and subsequently stabilized.HT growth,DBH growth stand basal area(BAS)and crown competition factor(CCF)signifi cantly infl uenced HCB and CL.The HCB was positively correlated with BAS,HT growth and DBH growth,but negatively correlated with CCF.The CL was positively correlated with BAS and CCF,but negatively correlated with DBH growth.Model fi tting and validation confi rmed that the mixed-eff ects model considering the stand and tree level random eff ects was accurate and reliable for predicting the HCB and CL dynamics.However,the models involving adding variance functions and time series correlation structure could not completely remove heterogeneity and autocorrelation,and the fi tting precision of the models was reduced.Therefore,from the point of view of application,we should take care to avoid setting up over-complex models.The HCB and CL dynamic models in our study may also be incorporated into stand growth and yield model systems in China.
基金Supported by the Construction Project of Party Branch Secretary’s Studio of "Double Leader" Teachers in Colleges and Universities of the Ministry of Education of ChinaThe Project of Party Construction Research of Yunnan University of Finance and Economics
文摘The integration and development of grass-roots Party organizations and accurate poverty alleviation is the focus in social development in the new period. This is also a new measure explored by the CPC Central Committee in the new historical period to solve rural reform and extricate the poor from poverty,and can effectively enhance the enthusiasm of the masses in poverty alleviation and development work. Xundian Hui and Yi Autonomous County is located in the mountainous area of northeast Yunnan Province. It is one of the 592 national key counties for poverty alleviation and development and one of the 38 continuous development counties in Wumeng Mountain area. Since the implementation of the accurate poverty alleviation strategy,Xundian County insists on getting rid of poverty to grasp the overall situation of county economic and social development,focus on the actual situation of the county people,and conscientiously grasp the key of industrial poverty alleviation. It regards industry as the fundamental driving force to realize poverty alleviation from " blood transfusion" to " blood creation",and innovates the model of " Party branch +" to help the poor out of poverty by industry. It has selected 187 agricultural enterprises( cooperatives,large households) to achieve full coverage of all registered poor households,and achieved remarkable results. It has realized that each poor village has one to two leading industries,and each poor household has one to two industrial income projects,having led 30 500 poor households to increase their average income by more than 1 850 yuan. The final incidence of poverty decreased from 26. 93% in 2014 to 0. 35% at the end of 2017,becoming one of the first counties in Yunnan Province to get rid of poverty. It is also the only county in Yunnan Province that has won the Antipoverty Organization Innovation Award of the State Council. Based on field research and interviews,this paper analyzes and summarizes the specific methods,main achievements,practical experience and popularization and application measures of Xundian County " Party Branch +" to promote industrial poverty alleviation,so as to provide necessary reference for accurate poverty reduction and poverty alleviation in similar mountainous areas of Yunnan Province and other provinces.
基金The National Natural Science Foundationof China (70473037)
文摘A 0-1 integer programming model for weekly fleet assignment was put forward based on linear network and weekly flight scheduling in China. In this model, the objective function is to maximize the total profit of fleet assignment, subject to the constraints of coverage, aircraft flow balance, fleet size, aircraft availability, aircraft usage, flight restriction, aircraft seat capacity, and stopover. Then the branch-and-bound algorithm based on special ordered set was applied to solve the model. At last, a real- wofld case study on an airline with 5 fleets, 48 aircrafts and 1 786 flight legs indicated that the profit increase was ￥ 1 591276 one week and the running time was no more than 4 rain, which shows that the model and algorithm are fairly good for domestic airline.
基金co-supported by the National Natural Science Foundation Project (No.40872137,40372103)Crisis Mines Study Project (No.20089948)Inner Mongolia Geological Exploring Important Project (No.2004-05)
文摘Mantle branch structure is the third tectonic unit of multiple evolution of a mantle branch. It is not only the main mechanism of intercontinental orogeny, but also an important ore-forming and ore-control structure. Studies on geotectonic evolution, regional geological characteristics and oreforming and ore-control structures have shown that since the Mesozoic the Da Hinggan Mts. region has entered a typical intercontinental orogenic stage, and it is closely related to mantle branch activities. The south-central segment of the Da Hinggan Mts. is a typical mantle branch structure and possesses obvious magmatic-metamorphic complexes in the core, detachment slip beds in the periphery and overlapped fault depression basins. Moreover, all of these are the principal factors leading to ore formation and ore control in the region. This paper also further explores the mechanism of mineralization in the south-central segment of the Da Hinggan, summaries the rules of mineralization, puts forward the models of mineralization and points out future ore-exploring orientation.
基金supported by the National Natural Science Foundation of China (10771185,10926036)Zhejiang Provinicial Natural Science Foundation of China (Y6090172)
文摘We consider a population-size-dependent branching chain in a general random environment.We give suffcident conditions for certain extinction and for non-certain extinction.The chain exhibits different asymptotic according to supk,θmk,θ1, mk,θn→1 as k →∞, n→∞, infk,θmk,θ1.
