Polynomial-basis response surface method has some shortcomings for truss structures in structural optimization,concluding the low fitting accuracy and the great computational effort. Based on the theory of approximati...Polynomial-basis response surface method has some shortcomings for truss structures in structural optimization,concluding the low fitting accuracy and the great computational effort. Based on the theory of approximation, a response surface method based on Multivariate Rational Function basis(MRRSM) is proposed. In order to further reduce the computational workload of MRRSM, focusing on the law between the cross-sectional area and the nodal displacements of truss structure, a conjecture that the determinant of the stiffness matrix and the corresponding elements of adjoint matrix involved in displacement determination are polynomials with the same order as their respective matrices, each term of which is the product of cross-sectional areas, is proposed. The conjecture is proved theoretically for statically determinate truss structure, and is shown corrected by a large number of statically indeterminate truss structures. The theoretical analysis and a large number of numerical examples show that MRRSM has a high fitting accuracy and less computational effort. Efficiency of the structural optimization of truss structures would be enhanced.展开更多
This paper establishes a diagnostic model for assessing the rationality of size structure of urban agglomerations(UAs) in China. The model is designed to determine from a three-dimensional index including size distrib...This paper establishes a diagnostic model for assessing the rationality of size structure of urban agglomerations(UAs) in China. The model is designed to determine from a three-dimensional index including size distribution index(SDI), size compactness index(SCI), and size efficiency index(SEI). The spatio-temporal pattern of size structure involving the studied 19 UAs and its implications are explored. The results indicate that size structure of China's UAs advanced from a low rationality development stage to a moderate rationality development stage in 1995-2015.Among them, the SDI and SEI were reasonably high, and the SCI was relatively low. Spatially, the high rationality UAs were distributed across eastern China, while the low rationality UAs were located in western China. UAs with positive size structure possessed typically a dual-or multicenter urban structure, while UAs with negative size structure usually presented as a single-center structure. The evolutionary trajectories of rationality of size structure of UAs can be summarized as four different stages. Our findings suggest that, in addition to consolidating the status of national-level UAs, the development of regional-level UAs should be promoted. Also, the fostering focus and direction should be oriented toward an UA with dual-or multicenter spatial structure.展开更多
The rationality of land use structure was evaluated with dynamic TOPSIS method based on changing data of land use from 2008 to 2011 in the Changsha-Zhuzhou-Xiangtan area. The results showed that during 2008- 2011,the ...The rationality of land use structure was evaluated with dynamic TOPSIS method based on changing data of land use from 2008 to 2011 in the Changsha-Zhuzhou-Xiangtan area. The results showed that during 2008- 2011,the rationality of land use structure was totally high,the dynamic value hi of Changsha,Zhuzhou,Xiangtan and the Changsha-Zhuzhou-Xiangtan area was 0. 7954,0. 7821,0. 8245 and0. 8186,respectively; the value Ci( tk) reflecting the rationality of land use structure at different time points was rapidly increased,and the gap between regions was not big and shrinking. According to the grey relational analysis,the change of different land use types had different effects on the rationality of land use structure: transportation land,the land for cities,towns and villages and the land for mining and industry are most highly correlated with the rationality of land use structure,while arable land,woodland,water area and water conservancy facility land have also an important impact on the rationality of land use structure; controlling the excessive growth of transportation land,the land for cities,towns and villages and the land for mining and industry,protecting arable land,forest land,water area and water conservancy facility land,and moderately increasing the garden plot,plays a decisive role in optimizing the land use structure in the Changsha-Zhuzhou-Xiangtan area.展开更多
In this paper, a kind of rationalism theory of shell is established which is of different mechanic characters in tension and in compression, and the finite element numerical analysis method is also described.
Alarm flood is one of the main problems in the alarm systems of industrial process. Alarm root-cause analysis and alarm prioritization are good for alarm flood reduction. This paper proposes a systematic rationalizati...Alarm flood is one of the main problems in the alarm systems of industrial process. Alarm root-cause analysis and alarm prioritization are good for alarm flood reduction. This paper proposes a systematic rationalization method for multivariate correlated alarms to realize the root cause analysis and alarm prioritization. An information fusion based interpretive structural model is constructed according to the data-driven partial correlation coefficient calculation and process knowledge modification. This hierarchical multi-layer model is helpful in abnormality propagation path identification and root-cause analysis. Revised Likert scale method is adopted to determine the alarm priority and reduce the blindness of alarm handling. As a case study, the Tennessee Eastman process is utilized to show the effectiveness and validity of proposed approach. Alarm system performance comparison shows that our rationalization methodology can reduce the alarm flood to some extent and improve the performance.展开更多
The“Belt and Road”initiative functions as a novel impetus for China’s external economic development within the framework of the new normal of economic growth.By leveraging panel data from 30 provinces and regions a...The“Belt and Road”initiative functions as a novel impetus for China’s external economic development within the framework of the new normal of economic growth.By leveraging panel data from 30 provinces and regions across China for the period of 2010 to 2020,this research assesses the influence of the“Belt and Road”initiative on the enhancement of the industrial structure along its trajectory.The findings indicate that:the most notable influence on the rationalization and progress of the industrial structure is observed in the eastern region,with the central region following suit,whereas the western region has yet to exhibit a significant transformation.The analysis delves into the role of technological innovation,concluding that the initiative primarily catalyzes optimization and upgrading through the effect of technological advancement.The study advances several pertinent policy recommendations to support and enhance these developments.展开更多
In density-based topological design, one expects that the final result consists of elements either black (solid material) or white (void), without any grey areas. Moreover, one also expects that the optimal topolo...In density-based topological design, one expects that the final result consists of elements either black (solid material) or white (void), without any grey areas. Moreover, one also expects that the optimal topology can be obtained by starting from any initial topology configuration. An improved structural topological optimization method for multidisplacement constraints is proposed in this paper. In the proposed method, the whole optimization process is divided into two optimization adjustment phases and a phase transferring step. Firstly, an optimization model is built to deal with the varied displacement limits, design space adjustments, and reasonable relations between the element stiffness matrix and mass and its element topology variable. Secondly, a procedure is proposed to solve the optimization problem formulated in the first optimization adjustment phase, by starting with a small design space and advancing to a larger deign space. The design space adjustments are automatic when the design domain needs expansions, in which the convergence of the proposed method will not be affected. The final topology obtained by the proposed procedure in the first optimization phase, can approach to the vicinity of the optimum topology. Then, a heuristic algorithm is given to improve the efficiency and make the designed structural topology black/white in both the phase transferring step and the second optimization adjustment phase. And the optimum topology can finally be obtained by the second phase optimization adjustments. Two examples are presented to show that the topologies obtained by the proposed method are of very good 0/1 design distribution property, and the computational efficiency is enhanced by reducing the element number of the design structural finite model during two optimization adjustment phases. And the examples also show that this method is robust and practicable.展开更多
A simple barotropic potential vorticity equation with the influence of dissipation is applied to investigate the nonlinear Rossby wave in a shear flow in the tropical atmophere. By the reduetive perturbation method, w...A simple barotropic potential vorticity equation with the influence of dissipation is applied to investigate the nonlinear Rossby wave in a shear flow in the tropical atmophere. By the reduetive perturbation method, we derive the rotational KdV (rKdV for short) equation. And then, with the help of Jaeobi elliptie functions, we obtain various periodic structures for these Rossby waves. It is shown that dissipation is very important for these periodic structures of rational form.展开更多
In selecting rational types of underground structures resisting explosion,in order to improve stress states of the structural section and make full use of material strength of each part of the section,the research met...In selecting rational types of underground structures resisting explosion,in order to improve stress states of the structural section and make full use of material strength of each part of the section,the research method of composite structures is presented. Adopting the analysis method of micro-section free body,equilibrium equations,constraint equations and deformation coordination equations are given. Making use of the concept of generalized work and directly introducing Lagrange multiplier specific in physical meaning,the validity of the constructed generalized functional is proved by using variation method. The rational rigidity matching relationship of composite structure section is presented through example calculations.展开更多
The representation method of heterogeneous material information is one of the key technologies of heterogeneous object modeling, but almost all the existing methods cannot represent non-uniform rational B-spline (NU...The representation method of heterogeneous material information is one of the key technologies of heterogeneous object modeling, but almost all the existing methods cannot represent non-uniform rational B-spline (NURBS) entity. According to the characteristics of NURBS, a novel data structure, named NURBS material data structure, is proposed, in which the geometrical coordinates, weights and material coordinates of NURBS heterogene- ous objects can be represented simultaneously. Based on this data structure, both direct representation method and inverse construction method of heterogeneous NURBS objects are introduced. In the direct representation method, three forms of NURBS heterogeneous objects are introduced by giving the geometry and material information of con- trol points, among which the homogeneous coordinates form is employed for its brevity and easy programming. In the inverse construction method, continuous heterogeneous curves and surfaces can he obtained by interpolating discrete points and curves with specified material information. Some examples are given to show the effectiveness of the pro- posed methods.展开更多
Since decision-making behavior has been in the focus both from a scientific and a professional position, there seems to be a dispute whether rational or intuitive decision making leads to better outcomes. By now, scho...Since decision-making behavior has been in the focus both from a scientific and a professional position, there seems to be a dispute whether rational or intuitive decision making leads to better outcomes. By now, scholars have agreed that effective organizations do not have the luxury to choose between the "applications" of intuitive or rational decision making. Instead, they try to understand how different factors like personality traits and problem characteristics influence the decision-making process. Reviewing the literature reveals that personality pre-determination and the structure of problems (e.g., well-structured problems (WSPs) versus ill-structured problems (ISPs)) seem to have a significant impact on the decision-making efficiency. Further, the review also shows that there is a lack of application-oriented empirical studies in this area of research. Therefore, the aim of this research paper is to propose a framework for an empirical study on how personality traits and problem structure influence the decision-making process. First, hypotheses are derived from the literature on how personality pre-determination and behavioral patterns in the decision-making process lead to higher socioeconomic efficiency within certain problem categories. Second, a causal model and a setup for a laboratory experiment are proposed to allow testing the hypotheses. Finally, the conclusions provide an outlook on how this research could support organizations in their decision-making processes.展开更多
Shanxi Province is a typical resource-based region. After years of economic transformation, the air quality has been at a low level for a long time. The rationalization of industrial structure can measure the effect o...Shanxi Province is a typical resource-based region. After years of economic transformation, the air quality has been at a low level for a long time. The rationalization of industrial structure can measure the effect of economic transformation and whether it has an important impact on air quality. Therefore, it is necessary to study the non-linear impact that the rationalization of industrial structure has had on air quality at different stages, which is of positive significance for the continuing transformation and upgrading of resource-based regions. This study constructs a threshold regression model based on the panel data of 11 provincial cities in Shanxi Province from 2004 to 2016. The results show that the rationalization of industrial structure had a double threshold effect on air quality under different threshold variables. On the whole, optimizing the rationalization of industrial structure in Shanxi Province can improve air quality, and the improvement effect dropped first, and then began to rise. As a result, the current energy transformation and upgrading process should focus on the rationalization of industrial structure to solve the conflict between air quality and economic development.展开更多
The Beijing-Tianjin-Hebei region is one of the regions with the most dynamic economies,highest degrees of openness,strongest innovation capacities and largest populations,as well as an important engine driving China’...The Beijing-Tianjin-Hebei region is one of the regions with the most dynamic economies,highest degrees of openness,strongest innovation capacities and largest populations,as well as an important engine driving China’s economic development.Currently,the development of the BeijingTianjin-Hebei region faces many difficulties,including an inefficient distribution of regional functions,imbalance in industrial structure,low sophistication,and serious overburdening of resources and the environment.Promoting the overall coordinated development of the region has become an urgent challenge.In this paper,according to the conventions of industrial structure optimization,the three core indicators of regional industrial structure rationalization,sophistication and ecologicalization are constructed.With the help of the grey dynamic correlation model,the three indicators are coupled with the economic growth rate,and the industrial structure optimization index of the Beijing-Tianjin-Hebei region is comprehensively measured.The study shows that rationalization of the industrial structure in the Beijing-Tianjin-Hebei region is increasing but that this trend is not obvious;sophistication of the industrial structure is relatively high and has also been operating at a high level;however,the overall ecological level of the industrial structure in the Beijing-Tianjin-Hebei region is not high and presents the characteristics of high in the middle and low at both ends.In terms of the relationship between industrial structure and economic growth in the Beijing-Tianjin-Hebei region,ecologicalization of the industrial structure has the greatest influence on economic growth,followed by sophistication of the industrial structure,and rationalization of the industrial structure has the weakest influence.展开更多
This paper lbcuses on the main characteristics of a tree-shaped timber structural system or simply tree-shaped. One of them is the complexity of its steel connections, responsible for the joint of bar elements, compou...This paper lbcuses on the main characteristics of a tree-shaped timber structural system or simply tree-shaped. One of them is the complexity of its steel connections, responsible for the joint of bar elements, compounding a complex structural system, which requires the application of the CYPECAD software version 2007 to solve the calculations problems. Its efficiency was confirmed by a variety of laboratory tests carried out with the whole structure. The tree-shaped is a timber structure that can be used in a large number of destinations, including residences, malls, sheds, hangars, etc.. Originally, it was conceived based on the well-known masterpiece "Sagrada Familia", whose author was Architect Antoni Gaudi I Cornet (1852-1926) in Barcelona/Spain. It was designed at the end of 19th century and its construction is still not finished. Gaudi inverted the logical order of the gothic concepts, i.e., light weights below and heavy weights above. Based on this concept, he always had in mind the figure of a tree in nature. The tree-shaped follows the same idea, using timber pieces connected by steel plates. Theoretical and numerical analyses have shown its efficiency and lightness for use in timber structures.展开更多
A new heterometallic cluster W2Ag2S4(tdt)2(PPh3)2·CH2Cl2(H2tdt=H2CH3C6H3S2)(Ⅱ) has been prepared from the reaction of a well-defined molecular building block W2S4(tdt)22-(I) with Ag complex. The compound has bee...A new heterometallic cluster W2Ag2S4(tdt)2(PPh3)2·CH2Cl2(H2tdt=H2CH3C6H3S2)(Ⅱ) has been prepared from the reaction of a well-defined molecular building block W2S4(tdt)22-(I) with Ag complex. The compound has been characterized by X-ray diffraction study, IR., UV-Vis Spectroscopy and cyclic voltammetry.Crystallographic data for the compound are: space group P21/n,a=17.234(4), b=17.622(4), c=19. 094(4) A,β= 99. 22(2)°,V=5704(2) A3, Z=4,final R=0. 042 and Rw=0. 049 for 5983 independent reflections with I≥3σ(I) The structure analysis reveals that the cluster contains a cubane-like core [W2Ag2S4]4+ . The coordination geometry of each tungsten atom is a square pyramid just as that in the building block. Two types of metal-metal bonds of W-W bond and W-Ag bond exist in the core. The distance between two Ag atoms is out of the range of bonding.展开更多
基金Supported by National Natural Science Foundation of China (Grant No.5150261)Shandong Provincial Natural Science Foundation of China (Grant No.ZR2015AM013)
文摘Polynomial-basis response surface method has some shortcomings for truss structures in structural optimization,concluding the low fitting accuracy and the great computational effort. Based on the theory of approximation, a response surface method based on Multivariate Rational Function basis(MRRSM) is proposed. In order to further reduce the computational workload of MRRSM, focusing on the law between the cross-sectional area and the nodal displacements of truss structure, a conjecture that the determinant of the stiffness matrix and the corresponding elements of adjoint matrix involved in displacement determination are polynomials with the same order as their respective matrices, each term of which is the product of cross-sectional areas, is proposed. The conjecture is proved theoretically for statically determinate truss structure, and is shown corrected by a large number of statically indeterminate truss structures. The theoretical analysis and a large number of numerical examples show that MRRSM has a high fitting accuracy and less computational effort. Efficiency of the structural optimization of truss structures would be enhanced.
基金supported by the National Social Science Foundation of China [Grant number:17CJY015]the Stragegic Priority Research Program of the Chinese Academy of Sciences [Grant number:XDA19040501]+1 种基金the Fundamental Research Funds for the Central Universities[Grant number:2018RW01]Beijing Natural Science Foundation [Grant number:9184035]
文摘This paper establishes a diagnostic model for assessing the rationality of size structure of urban agglomerations(UAs) in China. The model is designed to determine from a three-dimensional index including size distribution index(SDI), size compactness index(SCI), and size efficiency index(SEI). The spatio-temporal pattern of size structure involving the studied 19 UAs and its implications are explored. The results indicate that size structure of China's UAs advanced from a low rationality development stage to a moderate rationality development stage in 1995-2015.Among them, the SDI and SEI were reasonably high, and the SCI was relatively low. Spatially, the high rationality UAs were distributed across eastern China, while the low rationality UAs were located in western China. UAs with positive size structure possessed typically a dual-or multicenter urban structure, while UAs with negative size structure usually presented as a single-center structure. The evolutionary trajectories of rationality of size structure of UAs can be summarized as four different stages. Our findings suggest that, in addition to consolidating the status of national-level UAs, the development of regional-level UAs should be promoted. Also, the fostering focus and direction should be oriented toward an UA with dual-or multicenter spatial structure.
基金Supported by Hunan Provincial Natural Science Foundation(14JJ404214JJ2098)
文摘The rationality of land use structure was evaluated with dynamic TOPSIS method based on changing data of land use from 2008 to 2011 in the Changsha-Zhuzhou-Xiangtan area. The results showed that during 2008- 2011,the rationality of land use structure was totally high,the dynamic value hi of Changsha,Zhuzhou,Xiangtan and the Changsha-Zhuzhou-Xiangtan area was 0. 7954,0. 7821,0. 8245 and0. 8186,respectively; the value Ci( tk) reflecting the rationality of land use structure at different time points was rapidly increased,and the gap between regions was not big and shrinking. According to the grey relational analysis,the change of different land use types had different effects on the rationality of land use structure: transportation land,the land for cities,towns and villages and the land for mining and industry are most highly correlated with the rationality of land use structure,while arable land,woodland,water area and water conservancy facility land have also an important impact on the rationality of land use structure; controlling the excessive growth of transportation land,the land for cities,towns and villages and the land for mining and industry,protecting arable land,forest land,water area and water conservancy facility land,and moderately increasing the garden plot,plays a decisive role in optimizing the land use structure in the Changsha-Zhuzhou-Xiangtan area.
文摘In this paper, a kind of rationalism theory of shell is established which is of different mechanic characters in tension and in compression, and the finite element numerical analysis method is also described.
基金Supported by the National Natural Science Foundation of China(61473026,61104131)the Fundamental Research Funds for the Central Universities(JD1413)
文摘Alarm flood is one of the main problems in the alarm systems of industrial process. Alarm root-cause analysis and alarm prioritization are good for alarm flood reduction. This paper proposes a systematic rationalization method for multivariate correlated alarms to realize the root cause analysis and alarm prioritization. An information fusion based interpretive structural model is constructed according to the data-driven partial correlation coefficient calculation and process knowledge modification. This hierarchical multi-layer model is helpful in abnormality propagation path identification and root-cause analysis. Revised Likert scale method is adopted to determine the alarm priority and reduce the blindness of alarm handling. As a case study, the Tennessee Eastman process is utilized to show the effectiveness and validity of proposed approach. Alarm system performance comparison shows that our rationalization methodology can reduce the alarm flood to some extent and improve the performance.
文摘The“Belt and Road”initiative functions as a novel impetus for China’s external economic development within the framework of the new normal of economic growth.By leveraging panel data from 30 provinces and regions across China for the period of 2010 to 2020,this research assesses the influence of the“Belt and Road”initiative on the enhancement of the industrial structure along its trajectory.The findings indicate that:the most notable influence on the rationalization and progress of the industrial structure is observed in the eastern region,with the central region following suit,whereas the western region has yet to exhibit a significant transformation.The analysis delves into the role of technological innovation,concluding that the initiative primarily catalyzes optimization and upgrading through the effect of technological advancement.The study advances several pertinent policy recommendations to support and enhance these developments.
基金supported by the National Natural Science Foundation of China (10872036)the High Technological Research and Development Program of China (2008AA04Z118)the Airspace Natural Science Foundation (2007ZA23007)
文摘In density-based topological design, one expects that the final result consists of elements either black (solid material) or white (void), without any grey areas. Moreover, one also expects that the optimal topology can be obtained by starting from any initial topology configuration. An improved structural topological optimization method for multidisplacement constraints is proposed in this paper. In the proposed method, the whole optimization process is divided into two optimization adjustment phases and a phase transferring step. Firstly, an optimization model is built to deal with the varied displacement limits, design space adjustments, and reasonable relations between the element stiffness matrix and mass and its element topology variable. Secondly, a procedure is proposed to solve the optimization problem formulated in the first optimization adjustment phase, by starting with a small design space and advancing to a larger deign space. The design space adjustments are automatic when the design domain needs expansions, in which the convergence of the proposed method will not be affected. The final topology obtained by the proposed procedure in the first optimization phase, can approach to the vicinity of the optimum topology. Then, a heuristic algorithm is given to improve the efficiency and make the designed structural topology black/white in both the phase transferring step and the second optimization adjustment phase. And the optimum topology can finally be obtained by the second phase optimization adjustments. Two examples are presented to show that the topologies obtained by the proposed method are of very good 0/1 design distribution property, and the computational efficiency is enhanced by reducing the element number of the design structural finite model during two optimization adjustment phases. And the examples also show that this method is robust and practicable.
基金The project supports by National Natural Science Foundation of China under Grant No. 40233033
文摘A simple barotropic potential vorticity equation with the influence of dissipation is applied to investigate the nonlinear Rossby wave in a shear flow in the tropical atmophere. By the reduetive perturbation method, we derive the rotational KdV (rKdV for short) equation. And then, with the help of Jaeobi elliptie functions, we obtain various periodic structures for these Rossby waves. It is shown that dissipation is very important for these periodic structures of rational form.
文摘In selecting rational types of underground structures resisting explosion,in order to improve stress states of the structural section and make full use of material strength of each part of the section,the research method of composite structures is presented. Adopting the analysis method of micro-section free body,equilibrium equations,constraint equations and deformation coordination equations are given. Making use of the concept of generalized work and directly introducing Lagrange multiplier specific in physical meaning,the validity of the constructed generalized functional is proved by using variation method. The rational rigidity matching relationship of composite structure section is presented through example calculations.
基金Supported by National Natural Science Foundation of China (No. 60973079)Natural Science Foundation of Hebei Province (No. E2006000039)
文摘The representation method of heterogeneous material information is one of the key technologies of heterogeneous object modeling, but almost all the existing methods cannot represent non-uniform rational B-spline (NURBS) entity. According to the characteristics of NURBS, a novel data structure, named NURBS material data structure, is proposed, in which the geometrical coordinates, weights and material coordinates of NURBS heterogene- ous objects can be represented simultaneously. Based on this data structure, both direct representation method and inverse construction method of heterogeneous NURBS objects are introduced. In the direct representation method, three forms of NURBS heterogeneous objects are introduced by giving the geometry and material information of con- trol points, among which the homogeneous coordinates form is employed for its brevity and easy programming. In the inverse construction method, continuous heterogeneous curves and surfaces can he obtained by interpolating discrete points and curves with specified material information. Some examples are given to show the effectiveness of the pro- posed methods.
文摘Since decision-making behavior has been in the focus both from a scientific and a professional position, there seems to be a dispute whether rational or intuitive decision making leads to better outcomes. By now, scholars have agreed that effective organizations do not have the luxury to choose between the "applications" of intuitive or rational decision making. Instead, they try to understand how different factors like personality traits and problem characteristics influence the decision-making process. Reviewing the literature reveals that personality pre-determination and the structure of problems (e.g., well-structured problems (WSPs) versus ill-structured problems (ISPs)) seem to have a significant impact on the decision-making efficiency. Further, the review also shows that there is a lack of application-oriented empirical studies in this area of research. Therefore, the aim of this research paper is to propose a framework for an empirical study on how personality traits and problem structure influence the decision-making process. First, hypotheses are derived from the literature on how personality pre-determination and behavioral patterns in the decision-making process lead to higher socioeconomic efficiency within certain problem categories. Second, a causal model and a setup for a laboratory experiment are proposed to allow testing the hypotheses. Finally, the conclusions provide an outlook on how this research could support organizations in their decision-making processes.
基金The National Natural Science Foundation of China(71774105)The National Social Science Foundation of China(19BTJ053)+1 种基金The Soft Science Research Project in Shanxi Province of China(2019041012-4)The Institutions of Higher Learning in Shanxi Province Key Research Base of Humanities and Social Sciences Fund Project(2017324).
文摘Shanxi Province is a typical resource-based region. After years of economic transformation, the air quality has been at a low level for a long time. The rationalization of industrial structure can measure the effect of economic transformation and whether it has an important impact on air quality. Therefore, it is necessary to study the non-linear impact that the rationalization of industrial structure has had on air quality at different stages, which is of positive significance for the continuing transformation and upgrading of resource-based regions. This study constructs a threshold regression model based on the panel data of 11 provincial cities in Shanxi Province from 2004 to 2016. The results show that the rationalization of industrial structure had a double threshold effect on air quality under different threshold variables. On the whole, optimizing the rationalization of industrial structure in Shanxi Province can improve air quality, and the improvement effect dropped first, and then began to rise. As a result, the current energy transformation and upgrading process should focus on the rationalization of industrial structure to solve the conflict between air quality and economic development.
基金Supported by the Beijing Municipal Natural Science Foundation of China(9192001,9202002).
文摘The Beijing-Tianjin-Hebei region is one of the regions with the most dynamic economies,highest degrees of openness,strongest innovation capacities and largest populations,as well as an important engine driving China’s economic development.Currently,the development of the BeijingTianjin-Hebei region faces many difficulties,including an inefficient distribution of regional functions,imbalance in industrial structure,low sophistication,and serious overburdening of resources and the environment.Promoting the overall coordinated development of the region has become an urgent challenge.In this paper,according to the conventions of industrial structure optimization,the three core indicators of regional industrial structure rationalization,sophistication and ecologicalization are constructed.With the help of the grey dynamic correlation model,the three indicators are coupled with the economic growth rate,and the industrial structure optimization index of the Beijing-Tianjin-Hebei region is comprehensively measured.The study shows that rationalization of the industrial structure in the Beijing-Tianjin-Hebei region is increasing but that this trend is not obvious;sophistication of the industrial structure is relatively high and has also been operating at a high level;however,the overall ecological level of the industrial structure in the Beijing-Tianjin-Hebei region is not high and presents the characteristics of high in the middle and low at both ends.In terms of the relationship between industrial structure and economic growth in the Beijing-Tianjin-Hebei region,ecologicalization of the industrial structure has the greatest influence on economic growth,followed by sophistication of the industrial structure,and rationalization of the industrial structure has the weakest influence.
文摘This paper lbcuses on the main characteristics of a tree-shaped timber structural system or simply tree-shaped. One of them is the complexity of its steel connections, responsible for the joint of bar elements, compounding a complex structural system, which requires the application of the CYPECAD software version 2007 to solve the calculations problems. Its efficiency was confirmed by a variety of laboratory tests carried out with the whole structure. The tree-shaped is a timber structure that can be used in a large number of destinations, including residences, malls, sheds, hangars, etc.. Originally, it was conceived based on the well-known masterpiece "Sagrada Familia", whose author was Architect Antoni Gaudi I Cornet (1852-1926) in Barcelona/Spain. It was designed at the end of 19th century and its construction is still not finished. Gaudi inverted the logical order of the gothic concepts, i.e., light weights below and heavy weights above. Based on this concept, he always had in mind the figure of a tree in nature. The tree-shaped follows the same idea, using timber pieces connected by steel plates. Theoretical and numerical analyses have shown its efficiency and lightness for use in timber structures.
文摘A new heterometallic cluster W2Ag2S4(tdt)2(PPh3)2·CH2Cl2(H2tdt=H2CH3C6H3S2)(Ⅱ) has been prepared from the reaction of a well-defined molecular building block W2S4(tdt)22-(I) with Ag complex. The compound has been characterized by X-ray diffraction study, IR., UV-Vis Spectroscopy and cyclic voltammetry.Crystallographic data for the compound are: space group P21/n,a=17.234(4), b=17.622(4), c=19. 094(4) A,β= 99. 22(2)°,V=5704(2) A3, Z=4,final R=0. 042 and Rw=0. 049 for 5983 independent reflections with I≥3σ(I) The structure analysis reveals that the cluster contains a cubane-like core [W2Ag2S4]4+ . The coordination geometry of each tungsten atom is a square pyramid just as that in the building block. Two types of metal-metal bonds of W-W bond and W-Ag bond exist in the core. The distance between two Ag atoms is out of the range of bonding.