Large reflector antennas are widely used in radars, satellite communication, radio astronomy, and so on. The rapid developments in these fields have created demands for development of better performance and higher sur...Large reflector antennas are widely used in radars, satellite communication, radio astronomy, and so on. The rapid developments in these fields have created demands for development of better performance and higher surface accuracy. However, low accuracy and low effi- ciency are the common disadvantages for traditional panel alignment and adjustment. In order to improve the surface accuracy of large reflector antenna, a new method is pre- sented to determinate panel adjustment values from far field pattern. Based on the method of Physical Optics （PO）, the effect of panel facet displacement on radiation field value is derived. Then the linear system is constructed between panel adjustment vector and far field pattern. Using the method of Singular Value Decomposition （SVD）, the adjustment value for all panel adjustors are obtained by solving the linear equations. An experiment is conducted on a 3.7 m reflector antenna with 12 segmented panels. The results of simulation and test are similar, which shows that the presented method is feasible. Moreover, thediscussion about validation shows that the method can be used for many cases of reflector shape. The proposed research provides the instruction to adjust surface panels efficiently and accurately.展开更多
Although the design and synthesis of high-nuclear lanthanide clusters with specific shapes and functions have been an active area of research,effective experience and rules to guide further systematic expansion of lan...Although the design and synthesis of high-nuclear lanthanide clusters with specific shapes and functions have been an active area of research,effective experience and rules to guide further systematic expansion of lanthanide clusters with different connections are lacking.Herein,we adjusted the steric hindrance effects on the substituents of diacylhydrazone ligands(H_(4)L^(1),N’^(2),N’^(9)-bis((E)-2-hydroxybenzylidene)-1,10-phenanthroline-2,9-dicarboxydiazide;H_(4)L^(2),N’^(2),N’^(9)-bis((E)-2-hydroxy-3-methylbenzylidene)-1,10-phenanthroline-2,9-dicarboxydiazide;H_(4)L^(3),N’^(2),N’^(9)-bis((E)-3-(tert-butyl)-2-hydroxybenzylidene)-1,10-phenanthroline-2,9-dicarboxydiazide) and reacted them with Dy(NO_(3))_(3)·6H_(2)O under solvothermal conditions to obtain three dysprosium clusters(1-3) with different shapes.The molecular formulas of the abovementioned clusters are:[Dy_(1)_(6)(L^(1))_(3)(μ_(3)-OH)_(2)_(5)(NO_(3))_(1)_(1)(H_(2)O)_(1)_(0)]·4CH_(3)CN·8CH_(3)OH,[Dy_(1)_(0)(L^(2))_(4)(μ_(2)-OH)_(2)(μ_(3)-O)_(4)(NO_(3))_(4)(CH_(3)CN)_(2)(CH_(3)OH)_(4)(H_(2)O)_(8)]·CH_(3)OH·8H_(2)O,and[Dy_(5)(L^(3))_(2)(μ_(2)-CH_(3)O)(μ_(2)-OH)_(2)(μ_(4)-O)(NO_(3))_(2)(CH_(3)OH)_(2)]·6CH_(3)OH·2CH_(3)CN.Cluster 1 with a brucite-like planar structure crystallizes in the P2_(1)/n space group of the monoclinic system.The Dy(Ⅲ) ions in the cluster 1 structure are bridged by μ_(3)-OH^(-)to form a plane triangle shape.In addition,the structure of cluster 1 contains three layers of Dy(Ⅲ) ions(1+6+9) with different coordination environments.Cluster 2 crystallizes in the P̄1 space group of the triclinic system.The cluster core in cluster 2 is composed of two molecules of missing cubane Dy_(4)O_(6)and two Dy(Ⅲ) ions.The ligand(L^(2))500^(-)adopts two coordination modes(μ_(3)-η^(1)·η^(1)·η^(2)·η^(1)·η^(1)·η^(2)·η^(1)·η^(1) and μ_(5)-η^(2)·η^(1)·η^(1)·η^(1)·η^(1)·η^(1)·η^(1)·η^(1)·η^(2)) to chelate Dy(Ⅲ) ions.In addition,Dy(Ⅲ) ions in Dy_(4)O_(6)are connected by μ_(2)-OH^(-)and μ_(3)-OH^(-).Two molecules of planar Dy_(3)L^(3) intersect to form cluster 3,and it crystallizes in the I2/a space group of the monoclinic system.The analysis of the structure of clusters 1-3 shows that they are formed by a stepwise assembly process from outside to inside.To the best of our knowledge,a very small number of examples have reported that a series of differently connected dysprosium clusters were obtained through the regulation of substitution effects.Notably,we are the first to propose the out-to-in growth mechanism of planar high-nuclear dysprosium clusters.The results of the variable temperature AC susceptibility test show that clusters 1,2,and 3 exhibit single-molecule magnet-like behavior under zero-field conditions.展开更多
With rising costs of capital, labor and energy, cost efficiency and cost management have become important questions confronting the next stage of China＇s economic growth. By building a parametric cost frontier model ...With rising costs of capital, labor and energy, cost efficiency and cost management have become important questions confronting the next stage of China＇s economic growth. By building a parametric cost frontier model using panel data, this paper investigates the drivers of economic growth transformation from a cost perspective. According to our research, among various effects triggering corporate cost variations and in addition to the expansion of production scale, the largest effect is from technological progress, followed by the effect of factor price adjustment and the effect of efficiency gains. Within the decomposition of factor price adjustment effect, the energy factor effect is the most significant. Furthermore, energy price fluctuations are likely to become major factors restricting saving-based growth. Further study reveals that both the ownership reform and opening up of SOEs are favorable to reducing the costs generated by inefficiency. This paper provides empirical evidence for the driving mechanism of saving-based growth transformation as well as empirical evidence to support to the further deepening of property rights and market-oriented reforms.展开更多
Using age adjusted effective modulus(AAEM)method,creep of concrete filled steel tube(CFST)member was formulated considering of creep coefficient and aging coefficient.Ten CFST specimens were tested including eight for...Using age adjusted effective modulus(AAEM)method,creep of concrete filled steel tube(CFST)member was formulated considering of creep coefficient and aging coefficient.Ten CFST specimens were tested including eight for creep and two for shrinkage.The experimental result was compared with the computed result using AAEM in which the creep coefficient was taken from calibration of ACI model based on experimental result on sealed concrete,and aging coefficient was supplied from relaxation test on sealed concrete specimen.Furthermore,the creep of CFST member was analyzed using author's own subroutine to input concrete properties through user programmable feature(UPF)in ANSYS software.Comparison was made on authors' own experimental database,some existing experimental results,and results from AAEM and numerical analysis.Finally,the conditions of applicability of AAEM method are put forward,and numerical approach to compute creep of CFST specimen is delineated.展开更多
We report experimental realization of Raman spectra enhancement of copper phthalocyanine, using an on-chip metallic planar waveguide of the sub-millimeter scale. The oscillating ultrahigh order modes excited by the di...We report experimental realization of Raman spectra enhancement of copper phthalocyanine, using an on-chip metallic planar waveguide of the sub-millimeter scale. The oscillating ultrahigh order modes excited by the direct coupling method yield high optical intensity at resonance, which is different from the conventional strategy to create localized ＂hot spots.＂ The observed excitation efficiency of the Raman signal is significantly enhanced,owing to the high Q factor of the resonant cavity. Furthermore, effective modulation of the Raman intensity is available by adjusting the polymethyl methacrylate（PMMA） thickness in the guiding layer, i.e., by tuning the light–matter interaction length. A large modulation depth is verified through the fact that 10 times variation in the enhancement factor is observed in the experiment as the PMMA thickness varies from 7 to 23 μm.展开更多
The Chinese Government’s recent economic stimulus measures are attracting much attention because of its plan to increase people’s incomes and alleviate enterprises and residents’ economic burden.
基金Supported by National Natural Science Foundation of China(Grant Nos.51490661,51490660,51205301)National Key Basic Research Program of China(973 Program,Grant No.2015CB857100)Special Funding for Key Laboratory of Xinjiang Uygur Autonomous Region,China(Grant No.2014KL012)
文摘Large reflector antennas are widely used in radars, satellite communication, radio astronomy, and so on. The rapid developments in these fields have created demands for development of better performance and higher surface accuracy. However, low accuracy and low effi- ciency are the common disadvantages for traditional panel alignment and adjustment. In order to improve the surface accuracy of large reflector antenna, a new method is pre- sented to determinate panel adjustment values from far field pattern. Based on the method of Physical Optics （PO）, the effect of panel facet displacement on radiation field value is derived. Then the linear system is constructed between panel adjustment vector and far field pattern. Using the method of Singular Value Decomposition （SVD）, the adjustment value for all panel adjustors are obtained by solving the linear equations. An experiment is conducted on a 3.7 m reflector antenna with 12 segmented panels. The results of simulation and test are similar, which shows that the presented method is feasible. Moreover, thediscussion about validation shows that the method can be used for many cases of reflector shape. The proposed research provides the instruction to adjust surface panels efficiently and accurately.
基金supported by the National Natural Science Foundation of China(22075058 and 22061005)Guangxi Natural Science Foundation(2020GXNSFAA159075 and 2019GXNSFGA245003).
文摘Although the design and synthesis of high-nuclear lanthanide clusters with specific shapes and functions have been an active area of research,effective experience and rules to guide further systematic expansion of lanthanide clusters with different connections are lacking.Herein,we adjusted the steric hindrance effects on the substituents of diacylhydrazone ligands(H_(4)L^(1),N’^(2),N’^(9)-bis((E)-2-hydroxybenzylidene)-1,10-phenanthroline-2,9-dicarboxydiazide;H_(4)L^(2),N’^(2),N’^(9)-bis((E)-2-hydroxy-3-methylbenzylidene)-1,10-phenanthroline-2,9-dicarboxydiazide;H_(4)L^(3),N’^(2),N’^(9)-bis((E)-3-(tert-butyl)-2-hydroxybenzylidene)-1,10-phenanthroline-2,9-dicarboxydiazide) and reacted them with Dy(NO_(3))_(3)·6H_(2)O under solvothermal conditions to obtain three dysprosium clusters(1-3) with different shapes.The molecular formulas of the abovementioned clusters are:[Dy_(1)_(6)(L^(1))_(3)(μ_(3)-OH)_(2)_(5)(NO_(3))_(1)_(1)(H_(2)O)_(1)_(0)]·4CH_(3)CN·8CH_(3)OH,[Dy_(1)_(0)(L^(2))_(4)(μ_(2)-OH)_(2)(μ_(3)-O)_(4)(NO_(3))_(4)(CH_(3)CN)_(2)(CH_(3)OH)_(4)(H_(2)O)_(8)]·CH_(3)OH·8H_(2)O,and[Dy_(5)(L^(3))_(2)(μ_(2)-CH_(3)O)(μ_(2)-OH)_(2)(μ_(4)-O)(NO_(3))_(2)(CH_(3)OH)_(2)]·6CH_(3)OH·2CH_(3)CN.Cluster 1 with a brucite-like planar structure crystallizes in the P2_(1)/n space group of the monoclinic system.The Dy(Ⅲ) ions in the cluster 1 structure are bridged by μ_(3)-OH^(-)to form a plane triangle shape.In addition,the structure of cluster 1 contains three layers of Dy(Ⅲ) ions(1+6+9) with different coordination environments.Cluster 2 crystallizes in the P̄1 space group of the triclinic system.The cluster core in cluster 2 is composed of two molecules of missing cubane Dy_(4)O_(6)and two Dy(Ⅲ) ions.The ligand(L^(2))500^(-)adopts two coordination modes(μ_(3)-η^(1)·η^(1)·η^(2)·η^(1)·η^(1)·η^(2)·η^(1)·η^(1) and μ_(5)-η^(2)·η^(1)·η^(1)·η^(1)·η^(1)·η^(1)·η^(1)·η^(1)·η^(2)) to chelate Dy(Ⅲ) ions.In addition,Dy(Ⅲ) ions in Dy_(4)O_(6)are connected by μ_(2)-OH^(-)and μ_(3)-OH^(-).Two molecules of planar Dy_(3)L^(3) intersect to form cluster 3,and it crystallizes in the I2/a space group of the monoclinic system.The analysis of the structure of clusters 1-3 shows that they are formed by a stepwise assembly process from outside to inside.To the best of our knowledge,a very small number of examples have reported that a series of differently connected dysprosium clusters were obtained through the regulation of substitution effects.Notably,we are the first to propose the out-to-in growth mechanism of planar high-nuclear dysprosium clusters.The results of the variable temperature AC susceptibility test show that clusters 1,2,and 3 exhibit single-molecule magnet-like behavior under zero-field conditions.
文摘With rising costs of capital, labor and energy, cost efficiency and cost management have become important questions confronting the next stage of China＇s economic growth. By building a parametric cost frontier model using panel data, this paper investigates the drivers of economic growth transformation from a cost perspective. According to our research, among various effects triggering corporate cost variations and in addition to the expansion of production scale, the largest effect is from technological progress, followed by the effect of factor price adjustment and the effect of efficiency gains. Within the decomposition of factor price adjustment effect, the energy factor effect is the most significant. Furthermore, energy price fluctuations are likely to become major factors restricting saving-based growth. Further study reveals that both the ownership reform and opening up of SOEs are favorable to reducing the costs generated by inefficiency. This paper provides empirical evidence for the driving mechanism of saving-based growth transformation as well as empirical evidence to support to the further deepening of property rights and market-oriented reforms.
文摘Using age adjusted effective modulus(AAEM)method,creep of concrete filled steel tube(CFST)member was formulated considering of creep coefficient and aging coefficient.Ten CFST specimens were tested including eight for creep and two for shrinkage.The experimental result was compared with the computed result using AAEM in which the creep coefficient was taken from calibration of ACI model based on experimental result on sealed concrete,and aging coefficient was supplied from relaxation test on sealed concrete specimen.Furthermore,the creep of CFST member was analyzed using author's own subroutine to input concrete properties through user programmable feature(UPF)in ANSYS software.Comparison was made on authors' own experimental database,some existing experimental results,and results from AAEM and numerical analysis.Finally,the conditions of applicability of AAEM method are put forward,and numerical approach to compute creep of CFST specimen is delineated.
基金supported by the Natural Science Foundation of Jiangsu Province(Nos.BK20140246 and BK20160417)the National Natural Science Foundation of China(No.61371057,61601251,11404092,and61701261)+1 种基金the China Postdoctoral Science Foundation Funded Project(No.2016M601586)the Fundamental Research Funds for the Central Universities(No.2017B14914)
文摘We report experimental realization of Raman spectra enhancement of copper phthalocyanine, using an on-chip metallic planar waveguide of the sub-millimeter scale. The oscillating ultrahigh order modes excited by the direct coupling method yield high optical intensity at resonance, which is different from the conventional strategy to create localized ＂hot spots.＂ The observed excitation efficiency of the Raman signal is significantly enhanced,owing to the high Q factor of the resonant cavity. Furthermore, effective modulation of the Raman intensity is available by adjusting the polymethyl methacrylate（PMMA） thickness in the guiding layer, i.e., by tuning the light–matter interaction length. A large modulation depth is verified through the fact that 10 times variation in the enhancement factor is observed in the experiment as the PMMA thickness varies from 7 to 23 μm.
文摘The Chinese Government’s recent economic stimulus measures are attracting much attention because of its plan to increase people’s incomes and alleviate enterprises and residents’ economic burden.
