This paper presents a new method to seek the conserved quantity from a Lie symmetry without using either Lagrangians or Hamiltonians for nonholonomic systems. The differential equations of motion of the systems are es...This paper presents a new method to seek the conserved quantity from a Lie symmetry without using either Lagrangians or Hamiltonians for nonholonomic systems. The differential equations of motion of the systems are established. The definition of the Lie symmetrical transformations of the systems is given, which only depends upon the infinitesimal transformations of groups for the generalized coordinates. The conserved quantity is directly constructed in terms of the Lie symmetry of the systems. The condition under which the Lie symmetry can lead to the conserved quantity and the form of the conserved quantity are obtained. Finally, an example is given to illustrate the application of the result.展开更多
To extract the symmetric axis o{ rigid target accurately, a symmetric axis detection method is proposed based on Hough algorithm. A bullet is selected as a research object. Firstly, the original image is collected and...To extract the symmetric axis o{ rigid target accurately, a symmetric axis detection method is proposed based on Hough algorithm. A bullet is selected as a research object. Firstly, the original image is collected and the characteristics of the target image are analyzed. Because the symmetric axis detection depends on the edge detection of the image, it is necessary to use relevant operators to detect the edge and get all possible edge points. Secondly, all possible symmetric axes related to all contour points acquired are determined by Hough transform, and all possible inclination angles and intercepts and their ranges are obtained. Finally, by using least squares method, when the distance between the symmetric points of the contour points from the one edge and the contour points from the other edge is the minimum, the optimal symmetric axis is got. Simulation resuits show that the proposed method can improve noise-resistance and precision of symmetric axis detection and has certain practical value.展开更多
In this paper, we study the upper bounds on the mass insertion parameters (δAB^q)ij in the minimal super symmetric standard model. We found that the information from the measured branching ratio of B→ X8γ, X8l+l...In this paper, we study the upper bounds on the mass insertion parameters (δAB^q)ij in the minimal super symmetric standard model. We found that the information from the measured branching ratio of B→ X8γ, X8l+l- decay can help us to improve the upper bounds on the mass insertions parameters (δAB^u,d)3j,i3 Some regions allowed by the data of Br(B→ X8γ) are excluded by the requirement of an SM-like C7γ (rnb) imposedby the data of Br(B→ X8γ, X8l+l- ).展开更多
We investigate in detail the effects of R-parity lepton number violation onthe decay b_1 → bχ_1~0 in the R-parity violating minimal supersymmetric standard model (R_p-MSSM)under the present experimental constraints ...We investigate in detail the effects of R-parity lepton number violation onthe decay b_1 → bχ_1~0 in the R-parity violating minimal supersymmetric standard model (R_p-MSSM)under the present experimental constraints on R_p parameters. In our numerical calculations weconsider two cases of input parameters of the squark and slepton sectors, M_(squark) 【 M_(slepton)and M_(squark) 】 M_(slepton), for comparison. The results show that the relative R-parity violatingcorrection is not very sensitive to the mass of the lightest neutralino bχ_1~0 the degenerateR-parity violating coupling parameter λ′_2 but strongly depends on M_(squark), M_(slepton) tan βand tie degenerate R-parity violating coupling parameter λ′_1. The relative correction is about -4~ 3% and can exceed -6% in some region of parameter space. Therefore, precise experiment analyseson the decay b_1 → bχ_1~0 may provide a probe of the R-parity violation.展开更多
Traditional methods for detecting symmetry in image suffer greatly from the contrast of image and noise, and they all require some preprocessing. This paper presents a new method of image symmetry detection. This meth...Traditional methods for detecting symmetry in image suffer greatly from the contrast of image and noise, and they all require some preprocessing. This paper presents a new method of image symmetry detection. This method detects symmetry with phase information utilizing IogGabor wavelets,because phase information is stable and significant, while symmetric points produce patterns easy to be recognised and confirmable in local phase. Phase method does not require any preprocessing, and its result is accurate or invariant to contrast, rotation and illumination conditions. This method can detect mirror symmetry, rotating symmetry and curve symmetry at one time. Results of experiment show that, compared with pivotal element algorithm based on intensity information, phase method is more accurate and robust.展开更多
Deexcitation energies of superdeformed secondary minima of odd-odd A u and T1 isotopes are investigated with the relativistic mean field (RMF) model where the isoscalar-isovector coupling is included to change the s...Deexcitation energies of superdeformed secondary minima of odd-odd A u and T1 isotopes are investigated with the relativistic mean field (RMF) model where the isoscalar-isovector coupling is included to change the symmetry energy. It is verified by the theoretical analysis and numerical results that the deexcitation energies of superdeformed secondary minima relative to the ground states in these heavy nuclei are sensitive to differences in the symmetry energy. In particular, the linear correlation between the deexeitation energies of odd-odd Au and T1 isotopes and the neutron skin thickness in 208Pb is established. Moreover, explorations are extended to superdeformed candidates of other mass regions. It is found that the linear correlation can even be established between the deexcitation energies and the symmetry pressure at subsaturation density. These indicate that deexcitation energies can serve as a probe to the density dependence of the symmetry energy.展开更多
In this paper,we extend two important theorem in[1],[2]to the minimal submanifolds in a Locally symmetric and conformally flat Riemannian mainfold N^(+p).When N^(+p)is a space S_(1)^(+p) of constant curvature,our theo...In this paper,we extend two important theorem in[1],[2]to the minimal submanifolds in a Locally symmetric and conformally flat Riemannian mainfold N^(+p).When N^(+p)is a space S_(1)^(+p) of constant curvature,our theorems reduce to the theorems of[1],[2].展开更多
Conformal invariance and a new type of conserved quantities of mechanical systems with variable mass in phase space are studied. Firstly, the definition and determining equation of conformal invariance are presented. ...Conformal invariance and a new type of conserved quantities of mechanical systems with variable mass in phase space are studied. Firstly, the definition and determining equation of conformal invariance are presented. The relationship between the conformal invariance and the Lie symmetry is given, and the necessary and sufficient condition that the conformal invarianee would be the Lie symmetry under the infinitesimal transformations is provided. Secondly, a new type of conserved quantities of the conformal invariance are obtained by using the Lie symmetry of the system. Lastly, an example is given to illustrate the application of the results.展开更多
This paper discusses a design method for the control system of a weigh feeder that supplies powder and granular material at a constant rate. Most weigh feeders employed in industry are controlled by proportional and i...This paper discusses a design method for the control system of a weigh feeder that supplies powder and granular material at a constant rate. Most weigh feeders employed in industry are controlled by proportional and integral (PI) compensation, and the control performance is decided by the selection of parameters. To attain advanced control performance by PI control, the PI parameters are designed on the basis of generalized minimum variance control (GMVC). In this study, to achieve user-specified control performance by GMVC-based PI control, the design parameters of GMVC are automatically adjusted using a performance-adaptive method. The control performance discussed in this study consists of the variance of the control error and that of the difference in the control input. In a conventional performance-adaptive method, the variance of the control error is reduced. In this study, to reduce energy consumption and to achieve user-specified control performance, the variance of the difference in the control input is specified and the design parameter is determined. To demonstrate its effectiveness, the proposed method is applied to an actual weigh feeder.展开更多
According to the analysis of the problem of contract management, financial settlement and placement of coal trucks in coal business, a study is made on the coal management system. This system combines B/S and C/S toge...According to the analysis of the problem of contract management, financial settlement and placement of coal trucks in coal business, a study is made on the coal management system. This system combines B/S and C/S together, and it also uses three-tire application of ASP.NET which sets up a business subsystem based on functional module management in vehicle. Additionally, MFC solves the problems in weighing management systems. This system goes with unit testing, integration testing, and system testing, and the whole process realizes an effective monitoring from coal trucks applying for delivery, checking in, and weighing to checking out. Besides, it also secures precise and accurate weighing data, and deals with the new coming coal contract in a faster way. The real project indicates this system wins a very good reputation and it is worthy of spreading in a broader context.展开更多
Small and medium sized clothing enterprises have become an important force to promote China's economic transformation. But the shortage of funds in the development of small and medium sized clothing enterprises is st...Small and medium sized clothing enterprises have become an important force to promote China's economic transformation. But the shortage of funds in the development of small and medium sized clothing enterprises is still a major problem. The development of Intemet financial model is of great significance to the small and Medium Sized Clothing Enterprises .It is helpful to solve the problems of information asymmetry, credit rationing and high loan cost in the financing of small and medium sized clothing enterprises..In many financial models on the interne'., to our vast number of small and medium-sized enterprises provide convenient services, but in the face of this model using diffcrent opinions, and there is no pertinence, for most of the enterprises are usually similar situation was a summary and recommendations, there are a handful of targeted research ,This research is for research, in order to solve the financing problems of China's small and medium-sized garment enterprises countermeasures were studied to find a suitable China's small and medium-sized garment enterprises financing path with, for small and medium-sized garment enterprises in the capital needs of the guiding role, for the enterprise to avoid financial risk. the lnternet financial model to solve the financing problem of small and medium-sized garment enterprises play the important role, we should expand Internet banking, so that more small and medium-sized garment enterprises get better development.展开更多
The flow field distribution in centrifugal compressor is significantly affected by the non-axisymmetric geometry structure of the volute.The experimental and numerical simulation methods were adopted in this work to s...The flow field distribution in centrifugal compressor is significantly affected by the non-axisymmetric geometry structure of the volute.The experimental and numerical simulation methods were adopted in this work to study the compressor flow field distribution with different flow conditions.The results show that the pressure distribution in volute is characterized by the circumferential non-uniform phenomenon and the pressure fluctuation on the high static pressure zone propagates reversely to upstream,which results in the non-axisymmetric flow inside the compressor.The non-uniform level of pressure distribution in large flow condition is higher than that in small flow condition,its effect on the upstream flow field is also stronger.Additionally,the non-uniform circumferential pressure distribution in volute brings the non-axisymmetric flow at impeller outlet.In different flow conditions,the circumferential variation of the absolute flow angle at impeller outlet is also different.Meanwhile,the non-axisymmetric flow characteristics in internal impeller can be also reflected by the distribution of the mass flow.The high static pressure region of the volute corresponds to the decrease of mass flow in upstream blade channel,while the low static pressure zone of the volute corresponds to the increase of the mass flow.In small flow condition,the mass flow difference in the blade channel is bigger than that in the large flow condition.展开更多
A novel A-D-A (acceptor-donor-acceptor) type non-fullerene small molecule, A201, consisting of an asymmetric thieno[1,2-b]indaceno[5,6-b'lthienothiophene (TITI') unit as middle D part and 2-(3-oxo-2, 3-dihydroi...A novel A-D-A (acceptor-donor-acceptor) type non-fullerene small molecule, A201, consisting of an asymmetric thieno[1,2-b]indaceno[5,6-b'lthienothiophene (TITI') unit as middle D part and 2-(3-oxo-2, 3-dihydroinden-l-ylidene) malononitrile (IC) groups as end-capped A parts was designed and synthesized. The asymmetric TITT building block showed a higher dipole moment of 0.85 Debye (1 Debye = 3.33564 × 10^-3μcm) compared with the symmetric analogues of indacenodithiophene (IDT) and indacenodithieno[3,2-b]thiophene (IDTr) of 0.098 and 0.13 Debye, respectively. The solution-processed bulk heterojunction solar cells using a benzotriazole (BTA)-based polymer of J71 as donor and A201 as acceptor, showed a power conversion efficiency (PCE) of 9.36% with an open-circuit voltage (Voc) of 0.88 V, a short-circuit current Use) of 13.15 mA cm^-2, and a fill factor (FF) of 0.B7, under the illumination of AM 1.5G at 100 mW cm^-2. The high PCE of this material combination could be attributed to its broad absorption spectrum and the high hole mobility (#h) and electron mobility (μh) of 9.56 × 10^-4 and 5.1× 10^-4 cm^2 V^-1 s^-1, respectively. These results indicate that the asymmetric electron-donating segments are promising to construct A-D-A type small molecular acceptors, which could largely enhance the diversity of building blocks to design photovoltaic materials.展开更多
Based on the theory of the complex variable functions, the analysis of non-axisymmetric thermal stresses in a finite matrix containing a circular inclusion with functionally graded interphase is presented by means of ...Based on the theory of the complex variable functions, the analysis of non-axisymmetric thermal stresses in a finite matrix containing a circular inclusion with functionally graded interphase is presented by means of the least square boundary collocation technique. The distribution of thermal stress for the functionally graded interphase layer with arbitrary radial material parameters is derived by using the method of piece-wise homogeneous layers when the finite matrix is subjected to uniform heat flow. The effects of matrix size, interphase thickness and compositional gradient on the interfacial thermal stress are discussed in detail. Numerical results show that the magnitude and distribution of interfacial thermal stress in the inclusion and matrix can be designed properly by controlling these parameters.展开更多
Co-evolutionary theory assumes co-adapted characteristics are a positive response to counter those of another species,whereby co-evolved species reach an evolutionarily stable interaction through bilateral adaptation....Co-evolutionary theory assumes co-adapted characteristics are a positive response to counter those of another species,whereby co-evolved species reach an evolutionarily stable interaction through bilateral adaptation.However,evidence from the fig-fig wasp mutualistic system implies very different co-evolutionary selection mechanisms,due to the inherent conflict among interacted partners.Fig plants appear to have discriminatively enforced fig wasps to evolve"adaptation characteristics"that provide greater benefit to the fig,and fig wasps appear to have diversified their evolutionary strategies in response to discriminative enforcement by figs and competition among different fig wasp species.In what appears to be an asymmetric interaction,the prosperity of cooperative pollinating wasps should inevitably lead to population increases of parasitic individuals,thus resulting in localized extinctions of pollinating wasps.In response,the sanctioning of parasitic wasps by the fig should lead to a reduction in the parasitic wasp population.The meta-populations created by such asymmetric interactions may result in each population of coevolved species chaotically oscillated,temporally or evolutionarily.展开更多
文摘This paper presents a new method to seek the conserved quantity from a Lie symmetry without using either Lagrangians or Hamiltonians for nonholonomic systems. The differential equations of motion of the systems are established. The definition of the Lie symmetrical transformations of the systems is given, which only depends upon the infinitesimal transformations of groups for the generalized coordinates. The conserved quantity is directly constructed in terms of the Lie symmetry of the systems. The condition under which the Lie symmetry can lead to the conserved quantity and the form of the conserved quantity are obtained. Finally, an example is given to illustrate the application of the result.
基金National Natural Science Foundation of China(No.61171179,No.61227003)
文摘To extract the symmetric axis o{ rigid target accurately, a symmetric axis detection method is proposed based on Hough algorithm. A bullet is selected as a research object. Firstly, the original image is collected and the characteristics of the target image are analyzed. Because the symmetric axis detection depends on the edge detection of the image, it is necessary to use relevant operators to detect the edge and get all possible edge points. Secondly, all possible symmetric axes related to all contour points acquired are determined by Hough transform, and all possible inclination angles and intercepts and their ranges are obtained. Finally, by using least squares method, when the distance between the symmetric points of the contour points from the one edge and the contour points from the other edge is the minimum, the optimal symmetric axis is got. Simulation resuits show that the proposed method can improve noise-resistance and precision of symmetric axis detection and has certain practical value.
基金The project partly supported by National Natural Science Foundation of China under Grant Nos. 10275035 and 10575052 and the Research Foundation of Nanjing Normal University under Grant No. 214080A916 .
文摘In this paper, we study the upper bounds on the mass insertion parameters (δAB^q)ij in the minimal super symmetric standard model. We found that the information from the measured branching ratio of B→ X8γ, X8l+l- decay can help us to improve the upper bounds on the mass insertions parameters (δAB^u,d)3j,i3 Some regions allowed by the data of Br(B→ X8γ) are excluded by the requirement of an SM-like C7γ (rnb) imposedby the data of Br(B→ X8γ, X8l+l- ).
文摘We investigate in detail the effects of R-parity lepton number violation onthe decay b_1 → bχ_1~0 in the R-parity violating minimal supersymmetric standard model (R_p-MSSM)under the present experimental constraints on R_p parameters. In our numerical calculations weconsider two cases of input parameters of the squark and slepton sectors, M_(squark) 【 M_(slepton)and M_(squark) 】 M_(slepton), for comparison. The results show that the relative R-parity violatingcorrection is not very sensitive to the mass of the lightest neutralino bχ_1~0 the degenerateR-parity violating coupling parameter λ′_2 but strongly depends on M_(squark), M_(slepton) tan βand tie degenerate R-parity violating coupling parameter λ′_1. The relative correction is about -4~ 3% and can exceed -6% in some region of parameter space. Therefore, precise experiment analyseson the decay b_1 → bχ_1~0 may provide a probe of the R-parity violation.
文摘Traditional methods for detecting symmetry in image suffer greatly from the contrast of image and noise, and they all require some preprocessing. This paper presents a new method of image symmetry detection. This method detects symmetry with phase information utilizing IogGabor wavelets,because phase information is stable and significant, while symmetric points produce patterns easy to be recognised and confirmable in local phase. Phase method does not require any preprocessing, and its result is accurate or invariant to contrast, rotation and illumination conditions. This method can detect mirror symmetry, rotating symmetry and curve symmetry at one time. Results of experiment show that, compared with pivotal element algorithm based on intensity information, phase method is more accurate and robust.
基金Supported in part by the National Natural Science Foundation of China under Grant No.10975033the China Jiangsu Provincial Natural Science Foundation under Grant No.BK2009261+1 种基金 the Knowledge Innovation Project of the Chinese Academy of Sciences under Grant No.KJXC3-SYW-N2 the China Major State Basic Research Development Program under Grant No.2007CB815004
文摘Deexcitation energies of superdeformed secondary minima of odd-odd A u and T1 isotopes are investigated with the relativistic mean field (RMF) model where the isoscalar-isovector coupling is included to change the symmetry energy. It is verified by the theoretical analysis and numerical results that the deexcitation energies of superdeformed secondary minima relative to the ground states in these heavy nuclei are sensitive to differences in the symmetry energy. In particular, the linear correlation between the deexeitation energies of odd-odd Au and T1 isotopes and the neutron skin thickness in 208Pb is established. Moreover, explorations are extended to superdeformed candidates of other mass regions. It is found that the linear correlation can even be established between the deexcitation energies and the symmetry pressure at subsaturation density. These indicate that deexcitation energies can serve as a probe to the density dependence of the symmetry energy.
文摘In this paper,we extend two important theorem in[1],[2]to the minimal submanifolds in a Locally symmetric and conformally flat Riemannian mainfold N^(+p).When N^(+p)is a space S_(1)^(+p) of constant curvature,our theorems reduce to the theorems of[1],[2].
基金Supported by the Graduate Students' Innovative Foundation of China University of Petrolem (East China) under Grant No.S2009-19
文摘Conformal invariance and a new type of conserved quantities of mechanical systems with variable mass in phase space are studied. Firstly, the definition and determining equation of conformal invariance are presented. The relationship between the conformal invariance and the Lie symmetry is given, and the necessary and sufficient condition that the conformal invarianee would be the Lie symmetry under the infinitesimal transformations is provided. Secondly, a new type of conserved quantities of the conformal invariance are obtained by using the Lie symmetry of the system. Lastly, an example is given to illustrate the application of the results.
文摘This paper discusses a design method for the control system of a weigh feeder that supplies powder and granular material at a constant rate. Most weigh feeders employed in industry are controlled by proportional and integral (PI) compensation, and the control performance is decided by the selection of parameters. To attain advanced control performance by PI control, the PI parameters are designed on the basis of generalized minimum variance control (GMVC). In this study, to achieve user-specified control performance by GMVC-based PI control, the design parameters of GMVC are automatically adjusted using a performance-adaptive method. The control performance discussed in this study consists of the variance of the control error and that of the difference in the control input. In a conventional performance-adaptive method, the variance of the control error is reduced. In this study, to reduce energy consumption and to achieve user-specified control performance, the variance of the difference in the control input is specified and the design parameter is determined. To demonstrate its effectiveness, the proposed method is applied to an actual weigh feeder.
文摘According to the analysis of the problem of contract management, financial settlement and placement of coal trucks in coal business, a study is made on the coal management system. This system combines B/S and C/S together, and it also uses three-tire application of ASP.NET which sets up a business subsystem based on functional module management in vehicle. Additionally, MFC solves the problems in weighing management systems. This system goes with unit testing, integration testing, and system testing, and the whole process realizes an effective monitoring from coal trucks applying for delivery, checking in, and weighing to checking out. Besides, it also secures precise and accurate weighing data, and deals with the new coming coal contract in a faster way. The real project indicates this system wins a very good reputation and it is worthy of spreading in a broader context.
文摘Small and medium sized clothing enterprises have become an important force to promote China's economic transformation. But the shortage of funds in the development of small and medium sized clothing enterprises is still a major problem. The development of Intemet financial model is of great significance to the small and Medium Sized Clothing Enterprises .It is helpful to solve the problems of information asymmetry, credit rationing and high loan cost in the financing of small and medium sized clothing enterprises..In many financial models on the interne'., to our vast number of small and medium-sized enterprises provide convenient services, but in the face of this model using diffcrent opinions, and there is no pertinence, for most of the enterprises are usually similar situation was a summary and recommendations, there are a handful of targeted research ,This research is for research, in order to solve the financing problems of China's small and medium-sized garment enterprises countermeasures were studied to find a suitable China's small and medium-sized garment enterprises financing path with, for small and medium-sized garment enterprises in the capital needs of the guiding role, for the enterprise to avoid financial risk. the lnternet financial model to solve the financing problem of small and medium-sized garment enterprises play the important role, we should expand Internet banking, so that more small and medium-sized garment enterprises get better development.
基金National Natural Science Foundation of Chian(No.60272042)Natural Science Foundation of Henan Province(No.211050300)Natural Science Foundation of Henan University(No.XK01069)
文摘In this paper, we give a survey of matrix approach in wavelet theory , and describe some related results which were obtained by ourselves.
基金sponsored by the National Natural Science Foundation of China(No.51276017)
文摘The flow field distribution in centrifugal compressor is significantly affected by the non-axisymmetric geometry structure of the volute.The experimental and numerical simulation methods were adopted in this work to study the compressor flow field distribution with different flow conditions.The results show that the pressure distribution in volute is characterized by the circumferential non-uniform phenomenon and the pressure fluctuation on the high static pressure zone propagates reversely to upstream,which results in the non-axisymmetric flow inside the compressor.The non-uniform level of pressure distribution in large flow condition is higher than that in small flow condition,its effect on the upstream flow field is also stronger.Additionally,the non-uniform circumferential pressure distribution in volute brings the non-axisymmetric flow at impeller outlet.In different flow conditions,the circumferential variation of the absolute flow angle at impeller outlet is also different.Meanwhile,the non-axisymmetric flow characteristics in internal impeller can be also reflected by the distribution of the mass flow.The high static pressure region of the volute corresponds to the decrease of mass flow in upstream blade channel,while the low static pressure zone of the volute corresponds to the increase of the mass flow.In small flow condition,the mass flow difference in the blade channel is bigger than that in the large flow condition.
基金support from the Key Research Program of Frontier Sciences,Chinese Academy of Sciences (QYZDB-SSWSLH033)the National Key Research and Development Program of China (2017YFA0206600)+1 种基金the National Natural Science Foundation of China (51673048,51473040,21504019,51773046,and 21602040)the National Natural Science Foundation of Beijing (2162045)
文摘A novel A-D-A (acceptor-donor-acceptor) type non-fullerene small molecule, A201, consisting of an asymmetric thieno[1,2-b]indaceno[5,6-b'lthienothiophene (TITI') unit as middle D part and 2-(3-oxo-2, 3-dihydroinden-l-ylidene) malononitrile (IC) groups as end-capped A parts was designed and synthesized. The asymmetric TITT building block showed a higher dipole moment of 0.85 Debye (1 Debye = 3.33564 × 10^-3μcm) compared with the symmetric analogues of indacenodithiophene (IDT) and indacenodithieno[3,2-b]thiophene (IDTr) of 0.098 and 0.13 Debye, respectively. The solution-processed bulk heterojunction solar cells using a benzotriazole (BTA)-based polymer of J71 as donor and A201 as acceptor, showed a power conversion efficiency (PCE) of 9.36% with an open-circuit voltage (Voc) of 0.88 V, a short-circuit current Use) of 13.15 mA cm^-2, and a fill factor (FF) of 0.B7, under the illumination of AM 1.5G at 100 mW cm^-2. The high PCE of this material combination could be attributed to its broad absorption spectrum and the high hole mobility (#h) and electron mobility (μh) of 9.56 × 10^-4 and 5.1× 10^-4 cm^2 V^-1 s^-1, respectively. These results indicate that the asymmetric electron-donating segments are promising to construct A-D-A type small molecular acceptors, which could largely enhance the diversity of building blocks to design photovoltaic materials.
基金supported by the National Natural Science Foundation of China(Grant No.11232007)the Funding for Outstanding Doctoral Dissertation in Nanjing University of Aeronautics and Astronautics(Grant No.BCXJ11-03)Funding of Jiangsu Innovation Program for Graduate Education(Grant No.CXZZ11_0191)
文摘Based on the theory of the complex variable functions, the analysis of non-axisymmetric thermal stresses in a finite matrix containing a circular inclusion with functionally graded interphase is presented by means of the least square boundary collocation technique. The distribution of thermal stress for the functionally graded interphase layer with arbitrary radial material parameters is derived by using the method of piece-wise homogeneous layers when the finite matrix is subjected to uniform heat flow. The effects of matrix size, interphase thickness and compositional gradient on the interfacial thermal stress are discussed in detail. Numerical results show that the magnitude and distribution of interfacial thermal stress in the inclusion and matrix can be designed properly by controlling these parameters.
基金supported by the National Natural Science Foundation of China (NSFC) (31270433,31170408)National Science Fund for Distinguished Young Scholars (31325005)+2 种基金NSFC-Yunnan United Fund (U1302267)the West Light Foundation of the Chinese Academy of Sciencesthe Special Fund for the Excellent Youth of the Chinese Academy of Sciences (KSCX2-EW-Q-9)
文摘Co-evolutionary theory assumes co-adapted characteristics are a positive response to counter those of another species,whereby co-evolved species reach an evolutionarily stable interaction through bilateral adaptation.However,evidence from the fig-fig wasp mutualistic system implies very different co-evolutionary selection mechanisms,due to the inherent conflict among interacted partners.Fig plants appear to have discriminatively enforced fig wasps to evolve"adaptation characteristics"that provide greater benefit to the fig,and fig wasps appear to have diversified their evolutionary strategies in response to discriminative enforcement by figs and competition among different fig wasp species.In what appears to be an asymmetric interaction,the prosperity of cooperative pollinating wasps should inevitably lead to population increases of parasitic individuals,thus resulting in localized extinctions of pollinating wasps.In response,the sanctioning of parasitic wasps by the fig should lead to a reduction in the parasitic wasp population.The meta-populations created by such asymmetric interactions may result in each population of coevolved species chaotically oscillated,temporally or evolutionarily.