Based on the general requirements of the coordinated development of"ecological livable"and"affluent life"in the rural revitalization strategy,the evaluation index system of desertification control ...Based on the general requirements of the coordinated development of"ecological livable"and"affluent life"in the rural revitalization strategy,the evaluation index system of desertification control was constructed,the interaction between desertification control and regional social economy and the internal space-time coordination mechanism were explored,and the quality of desertification control and its coordination degree with regional economic development were quantitatively analyzed.The decoupling mechanism of desertification governance society economy system were analyzed,and the high level for the government to promote desertification governance,constructing ecological economy coordinated development pattern to provide decision basis to Xizang desertification governance-social economic system interaction and coupling coordination development as the research object,introducing the coupling decoupling model to measure the coupling coordination model and system coordination and decoupling decoupling.Desertification control in Xizang shows a trend of gradual improvement,but the overall level is still not high and there is a lot of room for optimization.The coupling coordination degree of desertification control-social and economic system is in a steady fluctuation trend,rising from D value less than 0.55 in 2004 to 0.87 in 2018,in a state of coordinated development(good),and grey prediction analysis shows that D value is in a continuous rise.The coupling coordination degree of the six prefecture-level cities in Xizang and Ngari region is different in time and space,but the overall development trend is coordinated.The development index of desertification control and the socio-economic development index show the interaction of strong decoupling,strong negative decoupling and weak decoupling,and there are interaction effects of desertification control,economic development and social development at different scales.展开更多
Based on a total of 16 indicators selected from the tourism and transport industries,an evaluation index system of the coupling and coordination development level of tourism and transport is constructed.The entropy va...Based on a total of 16 indicators selected from the tourism and transport industries,an evaluation index system of the coupling and coordination development level of tourism and transport is constructed.The entropy value method and the coupling coordination degree model are used to conduct an empirical study on the development level and coupling coordination level of the transport and tourism industries in Chengdu City from 2011 to 2020.The results show that,on the whole,the coupling coordination degree of transport and tourism in Chengdu is poor and has been in a state of mild to moderate dysfunction.The development level of tourism lagged behind the development of transport from 2011 to 2012,and the two were in a state of mild dysfunction.However,from 2013 onwards,the development level of tourism was prioritized over the development level of transport.This shift caused the coupling coordination degree of the two industries to decline sharply to 0.23305 in 2013.The development level of the tourism industry increased again,reaching 0.34206 in 2019,which marked an improvement.Consequently,the coordination degree of the transport and tourism industries evolved from moderate dislocation to mild dislocation.Finally,the results of the empirical research are analyzed,and corresponding suggestions are put forward to promote the sustainable growth of the transport and tourism industries in Chengdu City.These suggestions aim to improve the coupled and coordinated development level of the two industries.展开更多
The computational cost required by the Ensemble Kalman Filter (EnKF) is much larger than that of some simpler assimilation schemes, such as Optimal Interpolation (OI) or three-dimension variational as- similation ...The computational cost required by the Ensemble Kalman Filter (EnKF) is much larger than that of some simpler assimilation schemes, such as Optimal Interpolation (OI) or three-dimension variational as- similation (3DVAR). Ensemble optimal interpolation (EnOI), a crudely simplified implementation of EnKF, is sometimes used as a substitute in some oceanic applications and requires much less computational time than EnKF. In this paper, to compromise between computational cost and dynamic covariance, we use the idea of "dressing" a small size dynamical ensemble with a larger number of static ensembles in order to form an approximate dynamic covariance. The term "dressing" means that a dynamical ensemble seed from model runs is perturbed by adding the anomalies of some static ensembles. This dressing EnKF (DrEnKF for short) scheme is tested in assimilation of real altimetry data in the Pacific using the HYbrid Coordinate Ocean Model (HYCOM) over a four-year period. Ten dynamical ensemble seeds are each dressed by 10 static ensemble members selected from a 100-member static ensemble. Results are compared to two EnKF assimilation runs that use 10 and 100 dynamical ensemble members. Both temperature and salinity fields from the DrEnKF and the EnKF are compared to observations from Argo floats and an OI SST dataset. The results show that the DrEnKF and the 100-member EnKF yield similar root mean square errors (RMSE) at every model level. Error covariance matrices from the DrEnKF and the 100-member EnKF are also compared and show good agreement.展开更多
Variations in water exchange through the Kerama Gap (between Okinawa Island and Miyakojima Island) from 1979 to 2003 were estimated with the 0.08° Pacific HYbrid Coordinate Ocean Model (HYCOM). The model resu...Variations in water exchange through the Kerama Gap (between Okinawa Island and Miyakojima Island) from 1979 to 2003 were estimated with the 0.08° Pacific HYbrid Coordinate Ocean Model (HYCOM). The model results show that the mean transport through the Kerama Gap (KGT) from the Pacific Ocean to the East China Sea (ECS) was 2.1 Sv, which agrees well with the observed mean KGT (2.0 Sv) for 2009- 2010. Over the time period examined, the monthly KGT varied from -10.9 Sv to 15.8 Sv and had a standard deviation of +5.0 Sv. The water mainly enters the ECS via the subsurface layer (300-500 m) along the northeastern slope of the Kerama Gap and mainly flows out of the ECS into the southwest of the Kerama Gap. The seasonal and interannual variations of the KGT and the Kuroshio upstream transport were negatively correlated. The Kuroshio upstream transport was largest in summer and smallest in auamm while the KGT was smallest in summer (1.02 Sv) and largest in spring (2.94 Sv) and autumn (2.44 Sv). The seasonal and interarmual variations in the Kuroshio downstream (across the PN-line) transport differed significantly from the Kuroshio upstream transport but corresponded well with the KGT and the sum of the transport through the Kerama Gap and the Kuroshio upstream, which indicates that information about variation in the KGT is important for determining variation in the Kuroshio transport along the PN-line.展开更多
Forests provide enormous ecological, economic, and social benefits, as such forest development should be ori‐ented toward resource-economy-environment harmonization. This paper constructs a comprehensive evalua‐tion...Forests provide enormous ecological, economic, and social benefits, as such forest development should be ori‐ented toward resource-economy-environment harmonization. This paper constructs a comprehensive evalua‐tion index system and uses the coupled coordination degree model to measure the coordinated development level of China’ s forest resources-economy-environment system. The results show that, across 2006‒2020, the level of coupled coordinated development of China’ s forest resources-economy-environment composite system fluctuates in an upward trend, thus gradually developing from an initial imbalance to a high degree of coordi‐nation;the level of coordinated development of each subsystem of the forest resources, economy, and environ‐ment also shows an upward trend. The factors influencing the coordinated development of the forest resource economy-environment system are, in order, the government’ s financial capacity, market environment, scien‐tific and technological innovation capacity, level of economic development, and strength of policy implemen‐tation. Therefore, this paper proposes some measures to improve the coordinated development.展开更多
Traditional model for calculating performance parameters of a fix-pad journal bearing leads to heavy workload, complicated and changeable formulae as it requires deriving various geometric formulae with different bear...Traditional model for calculating performance parameters of a fix-pad journal bearing leads to heavy workload, complicated and changeable formulae as it requires deriving various geometric formulae with different bearing types such as circular journal bearing, dislocated bearing and elliptic bearing. Considering different pad preload ratios for non-standard bearing, traditional model not only becomes more complicated but also reduces scalability and promotion of the calculation programs. For the complexly case of traditional model while dealing with various fix-pad journal bearings, unified coordinate system model for performance calculation of fix-pad journal bearing is presented in the paper. A unified coordinate system with the bearing center at the origin is established, and the eccentricity ratio and attitude angle of axis relative to each pad are calculated through the coordinates of journal center and each pad center. Geometric description of fix-pad journal bearing is unified in this model, which can be used for both various standard bearing and non-standard bearing with different pad preload ratios. Validity of this model is verified with an elliptical bearing. Performance of a non-standard four-leaf bearing with different pad preload ratios is calculated based on this model. The calculation result shows that increasing preload ratio of the pad 1 and keeping that of the left three pads constant improves bearing capacity, stiffness and damping coefficients. This research presents a unified coordinate system model unifies performance calculation of fix-pad journal bearings and studied a non-standard four-leaf bearing with different pad preload ratios, the research conclusions provides new methods for performance calculation of fix-pad journal bearings.展开更多
A historical run(1993–2014)of a global,eddy-permitting,hybrid coordinate ocean model(HYCOM)is evaluated against observations.The authors evaluate several metrics in the model,including the spatial distribution of sea...A historical run(1993–2014)of a global,eddy-permitting,hybrid coordinate ocean model(HYCOM)is evaluated against observations.The authors evaluate several metrics in the model,including the spatial distribution of sea surface temperature(SST),the zonally averaged seasonal cycle of SST,the variability of the sea level anomaly(SLA),the zonally and meridionally averaged temperature and salinity,and the equatorial undercurrent.It is found that the simulated seasonal cycle of SST is 0.2–0.8 stronger than observed at midlatitudes.The modeled SST is 0.29°C warmer than the observed for the global ocean.the structure of the subsurface temperature and salinity is similar to the observed.moreover,the variability of SLA exhibits the same pattern as observed.The modeled equatorial undercurrent in the pacific ocean is weaker than observed,but stronger than the ecco reanalysis product.overall,the model can reproduce the large-scale ocean states,and is suitable for analyses seeking to better understand the dynamics and thermodynamics of the upper ocean,as well as ocean variability.展开更多
Promoting coordinated development of resources and environment is an important aspect of building a harmonious society and ecologically sustainable civilization. Here we provide scientific basis to promote the develop...Promoting coordinated development of resources and environment is an important aspect of building a harmonious society and ecologically sustainable civilization. Here we provide scientific basis to promote the development of ecologically sensitive civilization, via a mathematical statistics method that calculates the degree of coordinated development. This model is of great practical and social significance, providing strength to research around coordinated development of resources and economy. Based on evaluation of characteristics of the present resource environment and economic development of Shandong Peninsula city group, a coordinated measure of resource environment and economic development was calculated. Overall, the highest coordination measurement was found for Weihai, followed by Yantai, Qingdao, Ji'nan, Weifang, Rizhao, Zibo and Dongying. According to evaluation results of coordination measures for each city, we put forward suggestions for sustainable development of Shandong Peninsula region.展开更多
A hybrid coordinate ocean model (ltYCOM) is used to simulate the Kuroshio frontal eddies in the East China Sea (ECS). The research area is located (20°-32°N, 120°-132°E). Using tile simulatin...A hybrid coordinate ocean model (ltYCOM) is used to simulate the Kuroshio frontal eddies in the East China Sea (ECS). The research area is located (20°-32°N, 120°-132°E). Using tile simulating data, it is figured out that the Kuroshio frontal eddies occur in summer as well as in the other season in this area. The life cycle of the Kuroshio and its frontal eddies is different with the position. The life-cycle of the Kuroshio frontal eddies of the northwest Diaoyu Islands is about 14 d; and the life cycle of the Kuroshio frontal eddies of southwest Yakushima about 20 d. This result extends the in situ researching results greatly. In addition, the vertical impact depth of the Kuroshio frontal eddies is also changing with the position. On the whole, in the ECS, the maximum impact depth of the Kuroshio frontal eddies of the northwest Taiwan Islands is about 75 m; the maximum impact depth of the Kuroshio frontal eddies of the northwest Diaoyu Islands is more than 125 m, but no more than 200 m; and the maximum impact depth of the Kuroshio frontal eddies of southwest Yakushima is up to 100 m.展开更多
In order to resolve the coordination and optimization of the power network planning effectively, on the basis of introducing the concept of power intelligence center (PIC), the key factor power flow, line investment a...In order to resolve the coordination and optimization of the power network planning effectively, on the basis of introducing the concept of power intelligence center (PIC), the key factor power flow, line investment and load that impact generation sector, transmission sector and dispatching center in PIC were analyzed and a multi-objective coordination optimal model for new power intelligence center (NPIC) was established. To ensure the reliability and coordination of power grid and reduce investment cost, two aspects were optimized. The evolutionary algorithm was introduced to solve optimal power flow problem and the fitness function was improved to ensure the minimum cost of power generation. The gray particle swarm optimization (GPSO) algorithm was used to forecast load accurately, which can ensure the network with high reliability. On this basis, the multi-objective coordination optimal model which was more practical and in line with the need of the electricity market was proposed, then the coordination model was effectively solved through the improved particle swarm optimization algorithm, and the corresponding algorithm was obtained. The optimization of IEEE30 node system shows that the evolutionary algorithm can effectively solve the problem of optimal power flow. The average load forecasting of GPSO is 26.97 MW, which has an error of 0.34 MW compared with the actual load. The algorithm has higher forecasting accuracy. The multi-objective coordination optimal model for NPIC can effectively process the coordination and optimization problem of power network.展开更多
Coordinate transformation parameters between two spatial Cartesian coordinate systems can be solved from the positions of non-colinear corresponding points. Based on the characteristics of translation, rotation and zo...Coordinate transformation parameters between two spatial Cartesian coordinate systems can be solved from the positions of non-colinear corresponding points. Based on the characteristics of translation, rotation and zoom components of the transformation, the complete solution is divided into three steps. Firstly, positional vectors are regulated with respect to the centroid of sets of points in order to separate the translation compo- nents. Secondly, the scale coefficient and rotation matrix are derived from the regulated positions independent- ly and correlations among transformation model parameters are analyzed. It is indicated that this method is applicable to other sets of non-position data to separate the respective attributions for transformation parameters.展开更多
When there exists anisotropy in underground media elastic parameters of the observed coordinate possibly do not coincide with that of the natural coordinate. According to the theory that the density of potential energ...When there exists anisotropy in underground media elastic parameters of the observed coordinate possibly do not coincide with that of the natural coordinate. According to the theory that the density of potential energy, dissipating energy is independent of the coordinate, the relationship of elastic parameters between two coordinates is derived for two-phase anisotropic media. Then, pseudospectral method to solve wave equations of two-phase anisotropic media is derived. At last, we use this method to simulate wave propagation in two-phase anisotropic media four types of waves are observed in the snapshots, i.e., fast P wave and slow P wave, fast S wave and slow S wave. Shear wave splitting, SV wave cusps and elastic wave reflection and transmission are also observed.展开更多
To solve the inventory coordination model in a multi-stage, multi-customer supply chain, this paper first analyzes the third model (integer powers of two multipliers at each firm) studied by Moutaz Khouja (2003), ...To solve the inventory coordination model in a multi-stage, multi-customer supply chain, this paper first analyzes the third model (integer powers of two multipliers at each firm) studied by Moutaz Khouja (2003), and the authors take a numerical example to prove that the third model is irrational to miss feasible solution. Then this paper puts up a new improved model (integer multiplier at each firm), and takes the example to prove it gives better results than the integer powers of two multipliers at each firm.展开更多
Cultivated land is an important natural resource to ensure food,ecological and economic security.The cultivated land quality evaluation(CQE)is greatly significant for protecting and managing cultivated land.In this st...Cultivated land is an important natural resource to ensure food,ecological and economic security.The cultivated land quality evaluation(CQE)is greatly significant for protecting and managing cultivated land.In this study,320 counties in the black soil region of Northeast China(BSRNC)represent the research units used to construct the CQE system measuring the soil properties(SP),cultivated land productivity(CLP),ecological environment(EE)and social economy(SE).The total of 19 factors were selected to calculate the integrated fertility index(IFI)and divided into grades.Simultaneously,we used the coupling coordination degree model to comprehensively analyze the spatial pattern of the cultivated land quality(CLQ)in the BSRNC,and use the structural equation model(SEM)to analyze the driving mechanism.The results show the following:1)The CLQ of 262 counties in the BSRNC is in a state of coupling and coordination,and the coupling and coordination degree presents a spatial distribution pattern of‘high in the southwest and northeast,low in the northwest and southeast’.The coordinated development degree of 271 counties is between 0.4 and 0.6,which is in a transitional state between coordination and disorder.2)The CLQ in the BSRNC is generally good,with an average grade of 3.High-quality cultivated land accounts for 58.45%of all counties,middle-and upper-quality cultivated land accounts for 27.05%,and poor-quality cultivated land accounts for 14.49%.3)The SEM analysis shows that the SP,CLP,EE,and SE all influence the CLQ.Among them,the SP has the largest driving force on the CLQ,while the SE has the smallest driving force on it.The results confirm that the main factors affecting the evaluation results are crop productivity level,normalized difference vegetation index,ratio vegetation index,difference vegetation index,and organic carbon content.When implementing protection measures in counties with a low CLQ,considering a balanced coordination of multiple systems and reasonably controlling the quality degradation are important.This study provides the current situation and driving factors of the CLQ in the BSRNC and will play an important role in black soil governance and utilization.展开更多
Guangzhou,a significant hub city in the Guangdong-Hong Kong-Macao Greater Bay Area,has seen fast social and economic growth as well as steady progress in the degree of urbanization.This research,taking Guangzhou city ...Guangzhou,a significant hub city in the Guangdong-Hong Kong-Macao Greater Bay Area,has seen fast social and economic growth as well as steady progress in the degree of urbanization.This research,taking Guangzhou city as an example,aims to provide an understanding of how land resources,urbanization,and spatial planning are coordinated in the study area.It also aims to explore how the coordination degree of land resources,urbanization,and spatial planning changes over time.It seeks to provide effective suggestions for land resource protection,national spatial planning,and urban transformation development to promote the coordinated development of the Guangdong-Hong Kong-Macao Greater Bay Area into a world-class Bay Area.展开更多
A pheromone-based coordination approach and a prototype implementation for task allocation are pro- posed, for dealing with the static task allocation. The approach uses an indirect coordination mechanism, called pher...A pheromone-based coordination approach and a prototype implementation for task allocation are pro- posed, for dealing with the static task allocation. The approach uses an indirect coordination mechanism, called pheromone, which comes from the collective behavior of ant colonies for food foraging. Therefore it can automat- ically find efficient manufacturing cells for processing tasks and reduce communication overhead, which exists in the contract net protocol. Experimental results confirm that the approach has excellent stability and optimization ability for task allocation problems in a static environment.展开更多
This paper proposes an optimized and coordinated model predictive control(MPC) scheme for doublyfed induction generators(DFIGs) with DC-based converter system to improve the efficiency and dynamic performance in DC gr...This paper proposes an optimized and coordinated model predictive control(MPC) scheme for doublyfed induction generators(DFIGs) with DC-based converter system to improve the efficiency and dynamic performance in DC grids. In this configuration, the stator and rotor of the DFIG are connected to the DC bus via voltage source converters, namely, a rotor side converter(RSC) and a stator side converter(SSC). Optimized trajectories for rotorflux and stator current are proposed to minimize Joule losses of the DFIG, which is particularly advantageous at low and moderate torque. The coordinated MPC scheme is applied to overcome the weaknesses of the field-oriented control technique in the rotor flux-oriented frame, which makes the rotor flux stable and the stator current track its reference closely and quickly. Lastly, simulations and experiments are carried out to validate the feasibility of the control scheme and to analyze the steady-state and dynamic performance of the DFIG.展开更多
To comprehensively understand the law of urban-rural relationship and propose scientific measures of urban-rural coordinated development in Northeast China,this study uses the coupling coordination degree model and ge...To comprehensively understand the law of urban-rural relationship and propose scientific measures of urban-rural coordinated development in Northeast China,this study uses the coupling coordination degree model and geographically and temporally weighted regression(GTWR)model to analyze the spatial-temporal patterns and the corresponding driving mechanisms of its urban-rural coordination since 1990.The results are as follows.First,the urban-rural coupling coordination degree in Northeast China was very low and improved slowly,but its stages of evolution is a good interpretation of the strategic arrangements of China's urbanization.Second,the urban-rural coupling coordination degree in Northeast China had spatial differences and was characterized by central polarization,converging on urban agglomeration,which was high in the south and low in the north.Moreover,the gap between the north and south weakened.Third,the spatial-temporal evolution of the urban-rural coordination relationship in Northeast China was influenced by pulling from the central cities,pushing from rural transformation,and government regulations.The influence intensity of the three mechanisms was weak,but the pulling from the central cities was stronger than that of the other two mechanisms.Furthermore,the spatial difference between the three mechanisms determines the spatial pattern and its evolution of the urban-rural coordination relationship in Northeast China.Fourth,to promote the development of urban-rural coordination in Northeast China,it is essential to advance urban-rural economic correlation,enhance the government^role in regulating and guiding,and adopt different policies for each region in Northeast China.展开更多
The growth habit of the basic magnesium oxysulfate whisker was investigated based on the theoreticalmodelof anion coordination polyhedron growth units.It is found that typicalbasic magnesium oxysulfate whisker growth ...The growth habit of the basic magnesium oxysulfate whisker was investigated based on the theoreticalmodelof anion coordination polyhedron growth units.It is found that typicalbasic magnesium oxysulfate whisker growth is consistent with anion tetrahedralcoordination incorporation rules.The growth units of basic magnesium oxysulfate whiskers are [Mg-(OH)_4]^(2-) and HSO_4^-.[Mg-(OH)_4]^(2-) is the favorable growth unit and whisker growth is in the direction of the [Mg-(OH)_4]^(2-) combination.A plurality of [Mg-(OH)_4]^(2-) s combine and become a larger dimensionalgrowth unit in a one-dimensionaldirection.Then HSO_4^- and larger dimensionalgrowth units connect as basic magnesium sulfate whiskers,according to the structuralcharacteristics of the basic magnesium sulfate whisker,which can guide the synthesis of magnesium hydroxide whisker.展开更多
From the perspective of growth units, the growth mechanism of Mg2(OH)2CO3.3H2O whisker is investigated in this paper. Results show that the growth morphology of Mg2(OH)2CO33H2O whisker is consistent with the model...From the perspective of growth units, the growth mechanism of Mg2(OH)2CO3.3H2O whisker is investigated in this paper. Results show that the growth morphology of Mg2(OH)2CO33H2O whisker is consistent with the model of anion coordination polyhedron growth units. The growth solution Raman shift of Mg2(OH)2CO;3H2O was monitored using Raman spectroscopy. The growth units are [Mg-(OH)4]2- and H2COv The growth process of Mg2(OH)2COf3H2O whisker is as follows: growth unit [Mg-(OH)4]2- first incorporates into the larger dimension [Mg-(OH)4]2-, then the [Mg-(OH)4]2-n combines with H2CO3 into a linear skeleton Mg2(OH)2CO3 in the same line. Mg2(OH)2CO3 combines with H2O by hydrogen bonds and ultimately transforms into Mg2(OH)2COf3H2O whisker. Magnesium carbonate whiskers have a layered structure, each of which is made of magnesium, carbon, oxygen, with H2O in between each layer. When skeletons are superimposed within the same plane as a parallelepiped one, they grow into solid cuboid-shaped whiskers. When the parallelepiped skeletons planes combine with each other through the cascading links, they grow into hollow cylindrical whiskers.展开更多
基金supported by the Beijing Social Science Foundation Project(Grant No.18YJB011)the Ministry of Education Humanities and Social Science Research Fund for Youth Project(Grant No.20YJA790059)+2 种基金the National Social Science Foundation of China(Grant No.20FGLB022)the General Project of National Social Science Foundation of China(Grant No.19BGL052)the Innovation and Entrepreneurship Project of Beijing Forestry University(Grant No.X202110022111).
文摘Based on the general requirements of the coordinated development of"ecological livable"and"affluent life"in the rural revitalization strategy,the evaluation index system of desertification control was constructed,the interaction between desertification control and regional social economy and the internal space-time coordination mechanism were explored,and the quality of desertification control and its coordination degree with regional economic development were quantitatively analyzed.The decoupling mechanism of desertification governance society economy system were analyzed,and the high level for the government to promote desertification governance,constructing ecological economy coordinated development pattern to provide decision basis to Xizang desertification governance-social economic system interaction and coupling coordination development as the research object,introducing the coupling decoupling model to measure the coupling coordination model and system coordination and decoupling decoupling.Desertification control in Xizang shows a trend of gradual improvement,but the overall level is still not high and there is a lot of room for optimization.The coupling coordination degree of desertification control-social and economic system is in a steady fluctuation trend,rising from D value less than 0.55 in 2004 to 0.87 in 2018,in a state of coordinated development(good),and grey prediction analysis shows that D value is in a continuous rise.The coupling coordination degree of the six prefecture-level cities in Xizang and Ngari region is different in time and space,but the overall development trend is coordinated.The development index of desertification control and the socio-economic development index show the interaction of strong decoupling,strong negative decoupling and weak decoupling,and there are interaction effects of desertification control,economic development and social development at different scales.
基金Chongqing University of Science and Technology Postgraduate Innovation Program Project(Project No.YKJCX2320902)。
文摘Based on a total of 16 indicators selected from the tourism and transport industries,an evaluation index system of the coupling and coordination development level of tourism and transport is constructed.The entropy value method and the coupling coordination degree model are used to conduct an empirical study on the development level and coupling coordination level of the transport and tourism industries in Chengdu City from 2011 to 2020.The results show that,on the whole,the coupling coordination degree of transport and tourism in Chengdu is poor and has been in a state of mild to moderate dysfunction.The development level of tourism lagged behind the development of transport from 2011 to 2012,and the two were in a state of mild dysfunction.However,from 2013 onwards,the development level of tourism was prioritized over the development level of transport.This shift caused the coupling coordination degree of the two industries to decline sharply to 0.23305 in 2013.The development level of the tourism industry increased again,reaching 0.34206 in 2019,which marked an improvement.Consequently,the coordination degree of the transport and tourism industries evolved from moderate dislocation to mild dislocation.Finally,the results of the empirical research are analyzed,and corresponding suggestions are put forward to promote the sustainable growth of the transport and tourism industries in Chengdu City.These suggestions aim to improve the coupled and coordinated development level of the two industries.
基金supported by the Knowledge Innovation Program of Chinese Academy of Sciences (Grant No. KZCX1-YW-12-03)National Basic Research Program of China (2006CB403600)+3 种基金Project of Young Scientists Fund by National Natural Sciences Foundation of China (Grant No. 40606008)National Science and Technology Infrastructure Program(2006BAC03B04)supported by National Natural Sciences Foundation of China (Grant No.40531006)supported by a private donation from Trond Mohn c/o Frank Mohn AS, Bergenand the MERSEA project from the European Commission (Grant No. SIP3-CT-2003-502885)
文摘The computational cost required by the Ensemble Kalman Filter (EnKF) is much larger than that of some simpler assimilation schemes, such as Optimal Interpolation (OI) or three-dimension variational as- similation (3DVAR). Ensemble optimal interpolation (EnOI), a crudely simplified implementation of EnKF, is sometimes used as a substitute in some oceanic applications and requires much less computational time than EnKF. In this paper, to compromise between computational cost and dynamic covariance, we use the idea of "dressing" a small size dynamical ensemble with a larger number of static ensembles in order to form an approximate dynamic covariance. The term "dressing" means that a dynamical ensemble seed from model runs is perturbed by adding the anomalies of some static ensembles. This dressing EnKF (DrEnKF for short) scheme is tested in assimilation of real altimetry data in the Pacific using the HYbrid Coordinate Ocean Model (HYCOM) over a four-year period. Ten dynamical ensemble seeds are each dressed by 10 static ensemble members selected from a 100-member static ensemble. Results are compared to two EnKF assimilation runs that use 10 and 100 dynamical ensemble members. Both temperature and salinity fields from the DrEnKF and the EnKF are compared to observations from Argo floats and an OI SST dataset. The results show that the DrEnKF and the 100-member EnKF yield similar root mean square errors (RMSE) at every model level. Error covariance matrices from the DrEnKF and the 100-member EnKF are also compared and show good agreement.
基金Supported by the National Natural Science Foundation of China(No.41306020)the National Ocean Subject(No.XDA11020601)+1 种基金the NSFC Shandong Joint Found for Marine Science Research Centers(No.U1406401)the NSFC Innovative Group Grant(No.41421005)
文摘Variations in water exchange through the Kerama Gap (between Okinawa Island and Miyakojima Island) from 1979 to 2003 were estimated with the 0.08° Pacific HYbrid Coordinate Ocean Model (HYCOM). The model results show that the mean transport through the Kerama Gap (KGT) from the Pacific Ocean to the East China Sea (ECS) was 2.1 Sv, which agrees well with the observed mean KGT (2.0 Sv) for 2009- 2010. Over the time period examined, the monthly KGT varied from -10.9 Sv to 15.8 Sv and had a standard deviation of +5.0 Sv. The water mainly enters the ECS via the subsurface layer (300-500 m) along the northeastern slope of the Kerama Gap and mainly flows out of the ECS into the southwest of the Kerama Gap. The seasonal and interannual variations of the KGT and the Kuroshio upstream transport were negatively correlated. The Kuroshio upstream transport was largest in summer and smallest in auamm while the KGT was smallest in summer (1.02 Sv) and largest in spring (2.94 Sv) and autumn (2.44 Sv). The seasonal and interarmual variations in the Kuroshio downstream (across the PN-line) transport differed significantly from the Kuroshio upstream transport but corresponded well with the KGT and the sum of the transport through the Kerama Gap and the Kuroshio upstream, which indicates that information about variation in the KGT is important for determining variation in the Kuroshio transport along the PN-line.
基金funded by the National Social Science Foundation of China[Grant No.20BJY075].
文摘Forests provide enormous ecological, economic, and social benefits, as such forest development should be ori‐ented toward resource-economy-environment harmonization. This paper constructs a comprehensive evalua‐tion index system and uses the coupled coordination degree model to measure the coordinated development level of China’ s forest resources-economy-environment system. The results show that, across 2006‒2020, the level of coupled coordinated development of China’ s forest resources-economy-environment composite system fluctuates in an upward trend, thus gradually developing from an initial imbalance to a high degree of coordi‐nation;the level of coordinated development of each subsystem of the forest resources, economy, and environ‐ment also shows an upward trend. The factors influencing the coordinated development of the forest resource economy-environment system are, in order, the government’ s financial capacity, market environment, scien‐tific and technological innovation capacity, level of economic development, and strength of policy implemen‐tation. Therefore, this paper proposes some measures to improve the coordinated development.
基金Supported by National Natural Science Foundation of China(Grant No.51275395)Major National Basic Research Development Program of China(973 Program,Grant Nos.2009CB724304-2,2009CB724404)
文摘Traditional model for calculating performance parameters of a fix-pad journal bearing leads to heavy workload, complicated and changeable formulae as it requires deriving various geometric formulae with different bearing types such as circular journal bearing, dislocated bearing and elliptic bearing. Considering different pad preload ratios for non-standard bearing, traditional model not only becomes more complicated but also reduces scalability and promotion of the calculation programs. For the complexly case of traditional model while dealing with various fix-pad journal bearings, unified coordinate system model for performance calculation of fix-pad journal bearing is presented in the paper. A unified coordinate system with the bearing center at the origin is established, and the eccentricity ratio and attitude angle of axis relative to each pad are calculated through the coordinates of journal center and each pad center. Geometric description of fix-pad journal bearing is unified in this model, which can be used for both various standard bearing and non-standard bearing with different pad preload ratios. Validity of this model is verified with an elliptical bearing. Performance of a non-standard four-leaf bearing with different pad preload ratios is calculated based on this model. The calculation result shows that increasing preload ratio of the pad 1 and keeping that of the left three pads constant improves bearing capacity, stiffness and damping coefficients. This research presents a unified coordinate system model unifies performance calculation of fix-pad journal bearings and studied a non-standard four-leaf bearing with different pad preload ratios, the research conclusions provides new methods for performance calculation of fix-pad journal bearings.
基金supported by the National Key R&D Program of China [Grant No.2016YFC1401705]the National Natural Science Foundation of China [Grant Nos.41176015 and41776041]+2 种基金the Chinese Academy Sciences Project ‘Western Pacific Ocean System:Structure,Dynamics and Consequences’[Grant No.XDA11010203]confidencial military project [Grant No.315030401]the State Key Laboratory of Tropical Oceanography,South China Sea Institute of Oceanology,Chinese Academy of Sciences [Project No.LTO1501]
文摘A historical run(1993–2014)of a global,eddy-permitting,hybrid coordinate ocean model(HYCOM)is evaluated against observations.The authors evaluate several metrics in the model,including the spatial distribution of sea surface temperature(SST),the zonally averaged seasonal cycle of SST,the variability of the sea level anomaly(SLA),the zonally and meridionally averaged temperature and salinity,and the equatorial undercurrent.It is found that the simulated seasonal cycle of SST is 0.2–0.8 stronger than observed at midlatitudes.The modeled SST is 0.29°C warmer than the observed for the global ocean.the structure of the subsurface temperature and salinity is similar to the observed.moreover,the variability of SLA exhibits the same pattern as observed.The modeled equatorial undercurrent in the pacific ocean is weaker than observed,but stronger than the ecco reanalysis product.overall,the model can reproduce the large-scale ocean states,and is suitable for analyses seeking to better understand the dynamics and thermodynamics of the upper ocean,as well as ocean variability.
基金supported by Shandong Province Bureau of Statistics(No.KT15019)
文摘Promoting coordinated development of resources and environment is an important aspect of building a harmonious society and ecologically sustainable civilization. Here we provide scientific basis to promote the development of ecologically sensitive civilization, via a mathematical statistics method that calculates the degree of coordinated development. This model is of great practical and social significance, providing strength to research around coordinated development of resources and economy. Based on evaluation of characteristics of the present resource environment and economic development of Shandong Peninsula city group, a coordinated measure of resource environment and economic development was calculated. Overall, the highest coordination measurement was found for Weihai, followed by Yantai, Qingdao, Ji'nan, Weifang, Rizhao, Zibo and Dongying. According to evaluation results of coordination measures for each city, we put forward suggestions for sustainable development of Shandong Peninsula region.
基金The State Oceanic Administration Youth Funds of China under contract No.2012403the Public Science and Technology Research Funds Projects of Ocean of China under contract No.201005030+2 种基金the Special Funds for Basic Scientific Research Project of the First Institute of Oceanography,the State Ocean Administration of China under contract No.2010G12Water Marine Remote Sensing Survey and Research of China under contract No.908-01-ST10(Ⅱ)China’s Coastal Marine Optics and Remote Sensing Research under contract No.908-ZC-I-04
文摘A hybrid coordinate ocean model (ltYCOM) is used to simulate the Kuroshio frontal eddies in the East China Sea (ECS). The research area is located (20°-32°N, 120°-132°E). Using tile simulating data, it is figured out that the Kuroshio frontal eddies occur in summer as well as in the other season in this area. The life cycle of the Kuroshio and its frontal eddies is different with the position. The life-cycle of the Kuroshio frontal eddies of the northwest Diaoyu Islands is about 14 d; and the life cycle of the Kuroshio frontal eddies of southwest Yakushima about 20 d. This result extends the in situ researching results greatly. In addition, the vertical impact depth of the Kuroshio frontal eddies is also changing with the position. On the whole, in the ECS, the maximum impact depth of the Kuroshio frontal eddies of the northwest Taiwan Islands is about 75 m; the maximum impact depth of the Kuroshio frontal eddies of the northwest Diaoyu Islands is more than 125 m, but no more than 200 m; and the maximum impact depth of the Kuroshio frontal eddies of southwest Yakushima is up to 100 m.
基金Project (70671039) supported by the National Natural Science Foundation of China
文摘In order to resolve the coordination and optimization of the power network planning effectively, on the basis of introducing the concept of power intelligence center (PIC), the key factor power flow, line investment and load that impact generation sector, transmission sector and dispatching center in PIC were analyzed and a multi-objective coordination optimal model for new power intelligence center (NPIC) was established. To ensure the reliability and coordination of power grid and reduce investment cost, two aspects were optimized. The evolutionary algorithm was introduced to solve optimal power flow problem and the fitness function was improved to ensure the minimum cost of power generation. The gray particle swarm optimization (GPSO) algorithm was used to forecast load accurately, which can ensure the network with high reliability. On this basis, the multi-objective coordination optimal model which was more practical and in line with the need of the electricity market was proposed, then the coordination model was effectively solved through the improved particle swarm optimization algorithm, and the corresponding algorithm was obtained. The optimization of IEEE30 node system shows that the evolutionary algorithm can effectively solve the problem of optimal power flow. The average load forecasting of GPSO is 26.97 MW, which has an error of 0.34 MW compared with the actual load. The algorithm has higher forecasting accuracy. The multi-objective coordination optimal model for NPIC can effectively process the coordination and optimization problem of power network.
基金supported by the National Natural Science Foundation of China(41174025,41174026)
文摘Coordinate transformation parameters between two spatial Cartesian coordinate systems can be solved from the positions of non-colinear corresponding points. Based on the characteristics of translation, rotation and zoom components of the transformation, the complete solution is divided into three steps. Firstly, positional vectors are regulated with respect to the centroid of sets of points in order to separate the translation compo- nents. Secondly, the scale coefficient and rotation matrix are derived from the regulated positions independent- ly and correlations among transformation model parameters are analyzed. It is indicated that this method is applicable to other sets of non-position data to separate the respective attributions for transformation parameters.
文摘When there exists anisotropy in underground media elastic parameters of the observed coordinate possibly do not coincide with that of the natural coordinate. According to the theory that the density of potential energy, dissipating energy is independent of the coordinate, the relationship of elastic parameters between two coordinates is derived for two-phase anisotropic media. Then, pseudospectral method to solve wave equations of two-phase anisotropic media is derived. At last, we use this method to simulate wave propagation in two-phase anisotropic media four types of waves are observed in the snapshots, i.e., fast P wave and slow P wave, fast S wave and slow S wave. Shear wave splitting, SV wave cusps and elastic wave reflection and transmission are also observed.
文摘To solve the inventory coordination model in a multi-stage, multi-customer supply chain, this paper first analyzes the third model (integer powers of two multipliers at each firm) studied by Moutaz Khouja (2003), and the authors take a numerical example to prove that the third model is irrational to miss feasible solution. Then this paper puts up a new improved model (integer multiplier at each firm), and takes the example to prove it gives better results than the integer powers of two multipliers at each firm.
基金Under the auspices of National Key R&D Program of China(No.2021YFD1500104-4)National Natural Science Foundation of China(No.42171407,42077242)+1 种基金Natural Science Foundation of Jilin Province(No.20210101098JC)Special Investigation on Basic Science and Technology Resources(No.2021FY100406)。
文摘Cultivated land is an important natural resource to ensure food,ecological and economic security.The cultivated land quality evaluation(CQE)is greatly significant for protecting and managing cultivated land.In this study,320 counties in the black soil region of Northeast China(BSRNC)represent the research units used to construct the CQE system measuring the soil properties(SP),cultivated land productivity(CLP),ecological environment(EE)and social economy(SE).The total of 19 factors were selected to calculate the integrated fertility index(IFI)and divided into grades.Simultaneously,we used the coupling coordination degree model to comprehensively analyze the spatial pattern of the cultivated land quality(CLQ)in the BSRNC,and use the structural equation model(SEM)to analyze the driving mechanism.The results show the following:1)The CLQ of 262 counties in the BSRNC is in a state of coupling and coordination,and the coupling and coordination degree presents a spatial distribution pattern of‘high in the southwest and northeast,low in the northwest and southeast’.The coordinated development degree of 271 counties is between 0.4 and 0.6,which is in a transitional state between coordination and disorder.2)The CLQ in the BSRNC is generally good,with an average grade of 3.High-quality cultivated land accounts for 58.45%of all counties,middle-and upper-quality cultivated land accounts for 27.05%,and poor-quality cultivated land accounts for 14.49%.3)The SEM analysis shows that the SP,CLP,EE,and SE all influence the CLQ.Among them,the SP has the largest driving force on the CLQ,while the SE has the smallest driving force on it.The results confirm that the main factors affecting the evaluation results are crop productivity level,normalized difference vegetation index,ratio vegetation index,difference vegetation index,and organic carbon content.When implementing protection measures in counties with a low CLQ,considering a balanced coordination of multiple systems and reasonably controlling the quality degradation are important.This study provides the current situation and driving factors of the CLQ in the BSRNC and will play an important role in black soil governance and utilization.
文摘Guangzhou,a significant hub city in the Guangdong-Hong Kong-Macao Greater Bay Area,has seen fast social and economic growth as well as steady progress in the degree of urbanization.This research,taking Guangzhou city as an example,aims to provide an understanding of how land resources,urbanization,and spatial planning are coordinated in the study area.It also aims to explore how the coordination degree of land resources,urbanization,and spatial planning changes over time.It seeks to provide effective suggestions for land resource protection,national spatial planning,and urban transformation development to promote the coordinated development of the Guangdong-Hong Kong-Macao Greater Bay Area into a world-class Bay Area.
基金Supported by the National Natural Science Foundation of China(51175001,51175262)the New Century Excellent Talents in Ministry of Education of China(NCET-08)+3 种基金the Research Fund for Doctoral Program of Higher Education of China(20093218110020)the Natural Science Foundation of Anhui Province(1208085QE94)the Universities Natural Science Research Project of Anhui Province(KJ2012B008)the Doctoral Scientific Research Starting Foundation of Anhui Polytechnic University(2011YQQ006)~~
文摘A pheromone-based coordination approach and a prototype implementation for task allocation are pro- posed, for dealing with the static task allocation. The approach uses an indirect coordination mechanism, called pheromone, which comes from the collective behavior of ant colonies for food foraging. Therefore it can automat- ically find efficient manufacturing cells for processing tasks and reduce communication overhead, which exists in the contract net protocol. Experimental results confirm that the approach has excellent stability and optimization ability for task allocation problems in a static environment.
基金supported by National Natural Science Foundation of China(No.61473170)Key R&D Plan Project of Shandong Province,PRC(No.2016GSF115018)
文摘This paper proposes an optimized and coordinated model predictive control(MPC) scheme for doublyfed induction generators(DFIGs) with DC-based converter system to improve the efficiency and dynamic performance in DC grids. In this configuration, the stator and rotor of the DFIG are connected to the DC bus via voltage source converters, namely, a rotor side converter(RSC) and a stator side converter(SSC). Optimized trajectories for rotorflux and stator current are proposed to minimize Joule losses of the DFIG, which is particularly advantageous at low and moderate torque. The coordinated MPC scheme is applied to overcome the weaknesses of the field-oriented control technique in the rotor flux-oriented frame, which makes the rotor flux stable and the stator current track its reference closely and quickly. Lastly, simulations and experiments are carried out to validate the feasibility of the control scheme and to analyze the steady-state and dynamic performance of the DFIG.
基金Under the auspices of National Natural Science Foundation of China(No.41401182,41501173)Youth Fund for Humanities and Social Sciences of the Ministry of Education of China(No.19YJC630177)+2 种基金Natural Science Foundation of Heilongjiang Province(No.LH2019D008)University Nursing Program for Young Scholars with Creative Talents in Heilongjiang Province(No.UNPYSCT-2018194)Talent Introduction Project of Southwest University(No.SWU019020)。
文摘To comprehensively understand the law of urban-rural relationship and propose scientific measures of urban-rural coordinated development in Northeast China,this study uses the coupling coordination degree model and geographically and temporally weighted regression(GTWR)model to analyze the spatial-temporal patterns and the corresponding driving mechanisms of its urban-rural coordination since 1990.The results are as follows.First,the urban-rural coupling coordination degree in Northeast China was very low and improved slowly,but its stages of evolution is a good interpretation of the strategic arrangements of China's urbanization.Second,the urban-rural coupling coordination degree in Northeast China had spatial differences and was characterized by central polarization,converging on urban agglomeration,which was high in the south and low in the north.Moreover,the gap between the north and south weakened.Third,the spatial-temporal evolution of the urban-rural coordination relationship in Northeast China was influenced by pulling from the central cities,pushing from rural transformation,and government regulations.The influence intensity of the three mechanisms was weak,but the pulling from the central cities was stronger than that of the other two mechanisms.Furthermore,the spatial difference between the three mechanisms determines the spatial pattern and its evolution of the urban-rural coordination relationship in Northeast China.Fourth,to promote the development of urban-rural coordination in Northeast China,it is essential to advance urban-rural economic correlation,enhance the government^role in regulating and guiding,and adopt different policies for each region in Northeast China.
基金Funded by the National Natural Science Foundation of China(No.51272207)
文摘The growth habit of the basic magnesium oxysulfate whisker was investigated based on the theoreticalmodelof anion coordination polyhedron growth units.It is found that typicalbasic magnesium oxysulfate whisker growth is consistent with anion tetrahedralcoordination incorporation rules.The growth units of basic magnesium oxysulfate whiskers are [Mg-(OH)_4]^(2-) and HSO_4^-.[Mg-(OH)_4]^(2-) is the favorable growth unit and whisker growth is in the direction of the [Mg-(OH)_4]^(2-) combination.A plurality of [Mg-(OH)_4]^(2-) s combine and become a larger dimensionalgrowth unit in a one-dimensionaldirection.Then HSO_4^- and larger dimensionalgrowth units connect as basic magnesium sulfate whiskers,according to the structuralcharacteristics of the basic magnesium sulfate whisker,which can guide the synthesis of magnesium hydroxide whisker.
基金Funded by the National Natural Science Foundation of China(No.51272207)
文摘From the perspective of growth units, the growth mechanism of Mg2(OH)2CO3.3H2O whisker is investigated in this paper. Results show that the growth morphology of Mg2(OH)2CO33H2O whisker is consistent with the model of anion coordination polyhedron growth units. The growth solution Raman shift of Mg2(OH)2CO;3H2O was monitored using Raman spectroscopy. The growth units are [Mg-(OH)4]2- and H2COv The growth process of Mg2(OH)2COf3H2O whisker is as follows: growth unit [Mg-(OH)4]2- first incorporates into the larger dimension [Mg-(OH)4]2-, then the [Mg-(OH)4]2-n combines with H2CO3 into a linear skeleton Mg2(OH)2CO3 in the same line. Mg2(OH)2CO3 combines with H2O by hydrogen bonds and ultimately transforms into Mg2(OH)2COf3H2O whisker. Magnesium carbonate whiskers have a layered structure, each of which is made of magnesium, carbon, oxygen, with H2O in between each layer. When skeletons are superimposed within the same plane as a parallelepiped one, they grow into solid cuboid-shaped whiskers. When the parallelepiped skeletons planes combine with each other through the cascading links, they grow into hollow cylindrical whiskers.