In order to establish the quantitative relationship between equivalent strain and the performance index of the deformed material within the range of certain passes for equal channel angular processing （ECAP）, a new ...In order to establish the quantitative relationship between equivalent strain and the performance index of the deformed material within the range of certain passes for equal channel angular processing （ECAP）, a new approach to characterize the equivalent strain was proposed. The results show that there exists better accordance between mechanical property （such as hardness or strength） and equivalent strain after rolling and ECAP in a certain range of deformation amount, and Gauss equation can be satisfied among the equivalent strain and the mechanical properties for ECAP. Through regression analysis on the data of hardness and strength after the deformation, a more generalized expression of equivalent strain for ECAP is proposed as：ε=k0exp[-（k1M-k2）^2], where M is the strength or hardness of the material, k1 is the modified coefficient （k1∈ （0, 1））, ko and k2 are two parameters dependent on the critical strain and mechanical property that reaches saturation state for the material, respectively. In this expression the equivalent strain for ECAP is characterized novelly through the mechanical parameter relating to material property rather than the classical geometry equation.展开更多
The paper presents a fast algorithm for image retrieval using multi-channel textural features in medical picture archiving and communication system （PACS）. By choosing different linear or nonlinear operators in pred...The paper presents a fast algorithm for image retrieval using multi-channel textural features in medical picture archiving and communication system （PACS）. By choosing different linear or nonlinear operators in prediction and update lifting step, the linear or nonlinear M-band wavelet decomposition can be achieved in M-band lifting. It provides the advantages such as fast transform, in-place calculation and integer-integer transform. The set of wavelet moment forms multi-channel textural feature vector related to the texture distribution of each wavelet images. The experimental results of CT image database show that the retrieval approach of multi-channel textural features is effective for image indexing and has lower computational complexity and less memory. It is much easier to implement in hardware and suitable for the applications of real time medical processing system.展开更多
The impacts of channel morphology on the residues and ecological risks of 14 polychlorinated biphenyl(PCB) congeners in water and sediment were investigated in summer(July) and autumn(September) in the Chahe River,in ...The impacts of channel morphology on the residues and ecological risks of 14 polychlorinated biphenyl(PCB) congeners in water and sediment were investigated in summer(July) and autumn(September) in the Chahe River,in Nanjing,China.The residual concentrations of trichlorobiphenyls(tri-CBs,PCB 18) and tetra-CBs(PCB 52) in water were significantly higher than those of penta-CBs to deca-CBs,and the average residual concentration of ∑PCBs(sum of 14 PCB congeners) in summer was about six times higher than in autumn.However,the residues in sediment did not change significantly.Redundancy analysis(RDA) indicated that channel morphology and the corresponding environmental indices had significant impacts on PCB residues and their composition profiles in water and sediment.The overflow weir and lake-type watercourse may remarkably reduce the residual concentration and ecological risks of PCBs in water.The highest reduction percentages of the residual concentration and ecological risks of ∑PCBs induced by an overflow weir were 78%and 67%,respectively,and those induced by a lake-type watercourse were 36%and 70%,respectively.The watercourses with different channel morphologies were ranked by residual ∑PCBs concentrations in the following descending order:the natural ecological watercourse,vertical concrete watercourse,and vegetation-type riprap watercourse.However,they were ranked by residual ∑PCBs concentrations in sediment in the following descending order:the vertical concrete watercourse,vegetation-type riprap watercourse,and natural ecological watercourse.展开更多
We consider the physical limitations imposed on the information content of an image by the wave and quantum nature of light, when the image is obtained by illuminating a reflecting or transmitting planar object by nat...We consider the physical limitations imposed on the information content of an image by the wave and quantum nature of light, when the image is obtained by illuminating a reflecting or transmitting planar object by natural (i.e., fully thermalized) light, or by observation of an object emitting incoherent (thermal) radiation. The discreteness of the degrees of freedom and the statistical properties of thermal radiation are taken into account. We derive the maximum amount of information that can be retrieved from the object. This amount is always finite and is proportional to the area of the object, the solid angle under which the entrance pupil of the receiver is seen from the object, and the time of observation. An explicit expression for the information in the case where the information recorded by the receiver obeys Planck’s spectral distribution is obtained. The amount of information per photon of recorded radiation is a universal numerical constant, independent of the parameters of observation.展开更多
基金Projects(50471102,50671089) supported by the National Natural Science Foundation of China
文摘In order to establish the quantitative relationship between equivalent strain and the performance index of the deformed material within the range of certain passes for equal channel angular processing （ECAP）, a new approach to characterize the equivalent strain was proposed. The results show that there exists better accordance between mechanical property （such as hardness or strength） and equivalent strain after rolling and ECAP in a certain range of deformation amount, and Gauss equation can be satisfied among the equivalent strain and the mechanical properties for ECAP. Through regression analysis on the data of hardness and strength after the deformation, a more generalized expression of equivalent strain for ECAP is proposed as：ε=k0exp[-（k1M-k2）^2], where M is the strength or hardness of the material, k1 is the modified coefficient （k1∈ （0, 1））, ko and k2 are two parameters dependent on the critical strain and mechanical property that reaches saturation state for the material, respectively. In this expression the equivalent strain for ECAP is characterized novelly through the mechanical parameter relating to material property rather than the classical geometry equation.
文摘The paper presents a fast algorithm for image retrieval using multi-channel textural features in medical picture archiving and communication system （PACS）. By choosing different linear or nonlinear operators in prediction and update lifting step, the linear or nonlinear M-band wavelet decomposition can be achieved in M-band lifting. It provides the advantages such as fast transform, in-place calculation and integer-integer transform. The set of wavelet moment forms multi-channel textural feature vector related to the texture distribution of each wavelet images. The experimental results of CT image database show that the retrieval approach of multi-channel textural features is effective for image indexing and has lower computational complexity and less memory. It is much easier to implement in hardware and suitable for the applications of real time medical processing system.
基金supported by the National Natural Science Foundation of China(Grants No.41371307 and 51509129)the Open Foundation of State Key Laboratory of Pollution Control and Resource Reuse(Grant No.PCRRF12010)+2 种基金the State Key Laboratory of Soil and Sustainable Agriculture(Institute of Soil Science,Chinese Academy of Sciences)foundation(Grant No.0812201228)a project funded by the Priority Academic Program Development of Jiangsu Higher Education Institutionsthe Top-notch Academic Programs Project(TAPP)of Jiangsu Higher Education Institutions
文摘The impacts of channel morphology on the residues and ecological risks of 14 polychlorinated biphenyl(PCB) congeners in water and sediment were investigated in summer(July) and autumn(September) in the Chahe River,in Nanjing,China.The residual concentrations of trichlorobiphenyls(tri-CBs,PCB 18) and tetra-CBs(PCB 52) in water were significantly higher than those of penta-CBs to deca-CBs,and the average residual concentration of ∑PCBs(sum of 14 PCB congeners) in summer was about six times higher than in autumn.However,the residues in sediment did not change significantly.Redundancy analysis(RDA) indicated that channel morphology and the corresponding environmental indices had significant impacts on PCB residues and their composition profiles in water and sediment.The overflow weir and lake-type watercourse may remarkably reduce the residual concentration and ecological risks of PCBs in water.The highest reduction percentages of the residual concentration and ecological risks of ∑PCBs induced by an overflow weir were 78%and 67%,respectively,and those induced by a lake-type watercourse were 36%and 70%,respectively.The watercourses with different channel morphologies were ranked by residual ∑PCBs concentrations in the following descending order:the natural ecological watercourse,vertical concrete watercourse,and vegetation-type riprap watercourse.However,they were ranked by residual ∑PCBs concentrations in sediment in the following descending order:the vertical concrete watercourse,vegetation-type riprap watercourse,and natural ecological watercourse.
文摘We consider the physical limitations imposed on the information content of an image by the wave and quantum nature of light, when the image is obtained by illuminating a reflecting or transmitting planar object by natural (i.e., fully thermalized) light, or by observation of an object emitting incoherent (thermal) radiation. The discreteness of the degrees of freedom and the statistical properties of thermal radiation are taken into account. We derive the maximum amount of information that can be retrieved from the object. This amount is always finite and is proportional to the area of the object, the solid angle under which the entrance pupil of the receiver is seen from the object, and the time of observation. An explicit expression for the information in the case where the information recorded by the receiver obeys Planck’s spectral distribution is obtained. The amount of information per photon of recorded radiation is a universal numerical constant, independent of the parameters of observation.
