The fine grained dual phase (FG-DP) steel with ferrite grains of 2-4.5 μm and martensite islands smaller than 3 μm was obtained through the mechanism of deformation-enhanced ferrite transformation (DEFT). Mechan...The fine grained dual phase (FG-DP) steel with ferrite grains of 2-4.5 μm and martensite islands smaller than 3 μm was obtained through the mechanism of deformation-enhanced ferrite transformation (DEFT). Mechanical properties of the steel were tested at room temperature. The results indicated that with a similar volume fraction of martensite (about 20vol%),FG-DP steel exhibited a superior combination of higher strength and more rapid strain hardening at low strains compared with the coarse-grained dual phase (CG-DP) steel obtained by critical annealing. The combination of higher strength,large elongation,and more rapid strain hardening of FG-DP steel can be attributed to the fine ferrite grain and finely dispersed martensite islands. In addition,the uniformly distributed martensite islands in FG-DP steel have smaller interspacing compared with that of CG-DP steel. So,at the initial plastic deformation stage,the plastic deformation of ferrite was restrained and more pronounced load was transferred from ferrite to martensite. The plastic deformation of martensite in FG-DP steel started earlier.展开更多
This paper presents the application of dual-number matrix to the formulation of Jacobian equations of robot with redundancy, the analytical technique that is based on the dual-number matrices, a 3 × 3 matrix with...This paper presents the application of dual-number matrix to the formulation of Jacobian equations of robot with redundancy, the analytical technique that is based on the dual-number matrices, a 3 × 3 matrix with dualnumber elements, and the dual-number transformation method. Dual-number matrices make possible a concise representation of joint parameters. In particular, the method can effectively be used for direct determination of Jacobian matrices. It is shown that the proposed procedure contributes a simplified approach to the formulation of robotic kinematics, dynamics and control system modelling.展开更多
The generalized Ball curves of Wang-Said type with a position parameter L not only unify the Wang-Ball curves and the Said-Ball curves, but also include several useful intermediate curves. This paper presents the dual...The generalized Ball curves of Wang-Said type with a position parameter L not only unify the Wang-Ball curves and the Said-Ball curves, but also include several useful intermediate curves. This paper presents the dual functionals for the generalized Ball basis of Wang-Said type. The relevant basis transformation formulae are also worked out.展开更多
2021 was the first year of the“14th Five-year Plan”and the year in which the“30·60 Goals”were officially implemented.In the first year of the“Dual Carbon Goals”,domestic oil and gas enterprises vigorously e...2021 was the first year of the“14th Five-year Plan”and the year in which the“30·60 Goals”were officially implemented.In the first year of the“Dual Carbon Goals”,domestic oil and gas enterprises vigorously expanded their new energy businesses while actively developing their main businesses,bravely shouldered their responsibility for supply guarantee and comprehensively accelerated their green transformation,creating typical experience and practices.展开更多
A theorectical expression for the driving force and M_(?) point of martensitic transformation has been proposed.The M_(?) values using this expression are in good agreement with that obtained experimentally.It was fou...A theorectical expression for the driving force and M_(?) point of martensitic transformation has been proposed.The M_(?) values using this expression are in good agreement with that obtained experimentally.It was found that the values of M_(?) and M_(?) are not only related to the carbon content in martensite,but also to the volume fraction of ferrite.展开更多
The pathways to achieving carbon neutrality at the city level are diverse due to varying energy supply and demand conditions.Shanghai faces obstacles such as limited land resources,high costs of renewable energy techn...The pathways to achieving carbon neutrality at the city level are diverse due to varying energy supply and demand conditions.Shanghai faces obstacles such as limited land resources,high costs of renewable energy technologies,and instability of renewable energy.These challenges hinder the city’s efforts to achieve carbon peak and carbon neutrality(dual carbon).Therefore,Shanghai must identify and optimize its development path for renewable energy under the dual carbon goal.We employed the Low Emissions Analysis Platform Shanghai(LEAP-SH)model to simulate the impact of policies,such as industrial upgrading,energy efficiency improvement,energy structure optimization,increased technical innovation on energy,and ecological restoration,on the carbon emission pathways from 2022 to 2060 using five different scenarios.Our results indicate that Shanghai has the potential to achieve carbon neutrality in 2059 by promoting carbon reduction,pollution control,and green expansion.Moreover,we determined that the manufacturing industry;power generation industry;and transportation,storage,and mail services are the three major sectors for emission reduction under the dual carbon goal.Furthermore,the capacity and output of coal-fired power plants will be gradually replaced by offshore wind power in the dual carbon pathway.Finally,this study proposes countermeasures and suggestions for Shanghai to attain the dual carbon goal and high-quality development.展开更多
Automatic segmentation of medical images provides a reliable scientific basis for disease diagnosis and analysis.Notably,most existing methods that combine the strengths of convolutional neural networks(CNNs)and Trans...Automatic segmentation of medical images provides a reliable scientific basis for disease diagnosis and analysis.Notably,most existing methods that combine the strengths of convolutional neural networks(CNNs)and Transformers have made significant progress.However,there are some limitations in the current integration of CNN and Transformer technology in two key aspects.Firstly,most methods either overlook or fail to fully incorporate the complementary nature between local and global features.Secondly,the significance of integrating the multiscale encoder features from the dual-branch network to enhance the decoding features is often disregarded in methods that combine CNN and Transformer.To address this issue,we present a groundbreaking dual-branch cross-attention fusion network(DCFNet),which efficiently combines the power of Swin Transformer and CNN to generate complementary global and local features.We then designed the Feature Cross-Fusion(FCF)module to efficiently fuse local and global features.In the FCF,the utilization of the Channel-wise Cross-fusion Transformer(CCT)serves the purpose of aggregatingmulti-scale features,and the Feature FusionModule(FFM)is employed to effectively aggregate dual-branch prominent feature regions from the spatial perspective.Furthermore,within the decoding phase of the dual-branch network,our proposed Channel Attention Block(CAB)aims to emphasize the significance of the channel features between the up-sampled features and the features generated by the FCFmodule to enhance the details of the decoding.Experimental results demonstrate that DCFNet exhibits enhanced accuracy in segmentation performance.Compared to other state-of-the-art(SOTA)methods,our segmentation framework exhibits a superior level of competitiveness.DCFNet’s accurate segmentation of medical images can greatly assist medical professionals in making crucial diagnoses of lesion areas in advance.展开更多
In order to solve the problems of local maximum modulus extraction and threshold selection in the edge detection of finite resolution digital images, a new wavelet transform based adaptive dual threshold edge detec...In order to solve the problems of local maximum modulus extraction and threshold selection in the edge detection of finite resolution digital images, a new wavelet transform based adaptive dual threshold edge detection algorithm is proposed. The local maximum modulus is extracted by linear interpolation in wavelet domain. With the analysis on histogram, the image is filtered with an adaptive dual threshold method, which effectively detects the contours of small structures as well as the boundaries of large objects. A wavelet domain's propagation function is used to further select weak edges. Experimental results have shown the self adaptivity of the threshold to images having the same kind of histogram, and the efficiency even in noise tampered images.展开更多
Conventional quantization index modulation (QIM) watermarking uses the fixed quantization step size for the host signal.This scheme is not robust against geometric distortions and may lead to poor fidelity in some are...Conventional quantization index modulation (QIM) watermarking uses the fixed quantization step size for the host signal.This scheme is not robust against geometric distortions and may lead to poor fidelity in some areas of content.Thus,we proposed a quantization-based image watermarking in the dual tree complex wavelet domain.We took advantages of the dual tree complex wavelets (perfect reconstruction,approximate shift invariance,and directional selectivity).For the case of watermark detecting,the probability of false alarm and probability of false negative were exploited and verified by simulation.Experimental results demonstrate that the proposed method is robust against JPEG compression,additive white Gaussian noise (AWGN),and some kinds of geometric attacks such as scaling,rotation,etc.展开更多
We study the dual Dunkl-Sonine operator tSk,e on Rd and give expression of tSk,t, using Dunkl multiplier operators on Rd, Next, we study the extremal functions fλ, λ〉 0 related to the Dunkl multiplier operators, an...We study the dual Dunkl-Sonine operator tSk,e on Rd and give expression of tSk,t, using Dunkl multiplier operators on Rd, Next, we study the extremal functions fλ, λ〉 0 related to the Dunkl multiplier operators, and more precisely show that {fλ}λ〉0 converges uniformly to tSk,e(f) as λ→0 Certain examples based on Dunkl-heat and Dunkt-Poisson kernels are provided to illustrate the results.展开更多
A new simple and efficient dual tree analytic wavelet transform based on Discrete Cosine Harmonic Wavelet Transform DCHWT (ADCHWT) has been proposed and is applied for signal and image denoising. The analytic DCHWT ha...A new simple and efficient dual tree analytic wavelet transform based on Discrete Cosine Harmonic Wavelet Transform DCHWT (ADCHWT) has been proposed and is applied for signal and image denoising. The analytic DCHWT has been realized by applying DCHWT to the original signal and its Hilbert transform. The shift invariance and the envelope extraction properties of the ADCHWT have been found to be very effective in denoising speech and image signals, compared to that of DCHWT.展开更多
The Chinese economy is currently undergoing a digital transformation.New growth drivers are replacing old ones,creating a new development landscape.Countries with strong digital industries will be the first to reap th...The Chinese economy is currently undergoing a digital transformation.New growth drivers are replacing old ones,creating a new development landscape.Countries with strong digital industries will be the first to reap the benefits of digitalization.For China,the transformation to a digital economy is both of inevitability and heterogeneity fueled by dual circulations.Crowded out from more skill-based digitalized sectors,less-skilled labor moves to less digitalized sectors.New capital,industries and technology clusters emerge as new drivers of manufacturing and service sector development.With its large domestic market and industrial competitiveness,China has fostered a new development landscape of“dual circulations”.展开更多
The majority of existing high-power laser therapeutic instruments employ a single wavelength for a single target;thus,they do not meet the requirements for clinical treatment.Therefore,this study designs an optical sy...The majority of existing high-power laser therapeutic instruments employ a single wavelength for a single target;thus,they do not meet the requirements for clinical treatment.Therefore,this study designs an optical system for a dual-wavelength high-power laser therapeutic device with a variable spot size.The waist of the short arm of the optical cavity and the G1G2 parameter(G-parameter equivalent cavity method)is calculated using MATLAB software,the spot size and divergence angle on the lens are calculated using an ABCD matrix,and the distance between the treatment spot at different spot sizes and the transformation lens is calculated in order to design the treatment handpiece.Experiments are conducted to analyze the stability at an output power of 532 nm before beam combination and the power loss after beam combination.The results show that the output power stability of the 532-nm beam varies by less than 2%over 150 min,and the loss of both wavelengths is less than 20%,which meets the clinical requirements of the system.The safety performance can meet the requirements of national general standards for medical electrical safety.The proposed dual-wavelength laser therapy instrument has both visible wave and near-infrared wave characteristics;thus,it can accurately target both superficial vessels and vessels with a larger diameter and deeper position.This therapeutic device has the advantages of simple operation,stable and reliable laser output,high security and strong anti-interference ability,and meets the comprehensive clinical treat-ment demands of vascular diseases.展开更多
A dual-CCD simulating human eyes and neck (DSHEN) vision system is putforward. Its structure and principle are introduced. The DSREN vision system can perform somemovements simulating human eyes and neck by means of f...A dual-CCD simulating human eyes and neck (DSHEN) vision system is putforward. Its structure and principle are introduced. The DSREN vision system can perform somemovements simulating human eyes and neck by means of four rotating joints, and realize preciseobject recognizing and distance measuring in all orientations. The mathematic model of the DSHENvision system is built, and its movement equation is solved. The coordinate error and measureprecision affected by the movement parameters are analyzed by means of intersection measuringmethod. So a theoretic foundation for further research on automatic object recognizing and precisetarget tracking is provided.展开更多
The C-Mn and C-Mn-Nb steels were thermo-mechanically processed to develop dual phase steel and to study the effect of controlled rolling on the martensitic hardenability of austenite. The steel specimens were intercri...The C-Mn and C-Mn-Nb steels were thermo-mechanically processed to develop dual phase steel and to study the effect of controlled rolling on the martensitic hardenability of austenite. The steel specimens were intercritically annealed at 790℃, rolled at that temperature to the reductions of 10%, 23%, and 47% and immediately cooled at different rates. Quantitative metallography was used to construct the microstructure map, which illustrated that increasing deformation progressively reduced the proportion of new ferrite formed at all cooling rates and increased the amount of martensite at fast and intermediate rates. The martensitic hardenability of austenite remaining after all the rolling reductions was plotted as a function of cooling rates. It was observed that for the austenite-martensite conversion efficiencies greater than about 25%, controlled rolling increased the martensitic hardenability of austenite.展开更多
In the investigation on fracture mechanics,the potential function was introduced, and the moving differential equation was constructed. By making Laplace and Fourier transformation as well as sine and cosine transform...In the investigation on fracture mechanics,the potential function was introduced, and the moving differential equation was constructed. By making Laplace and Fourier transformation as well as sine and cosine transformation to moving differential equations and various responses, the dual equation which is constructed from boundary conditions lastly was solved. This method of investigating dynamic crack has become a more systematic one that is used widely. Some problems are encountered when the dynamic crack is studied. After the large investigation on the problems, it is discovered that during the process of mathematic derivation, the method is short of precision, and the derived results in this method are accidental and have no credibility.A model for example is taken to explain the problems existing in initial deriving process of the integral_transformation method of dynamic crack.展开更多
A nonlinear dual-porosity model considering a quadratic gradient term is presented. Assuming the pressure difference between matrix and fractures as a primary unknown, to avoid solving the simultaneous system of equat...A nonlinear dual-porosity model considering a quadratic gradient term is presented. Assuming the pressure difference between matrix and fractures as a primary unknown, to avoid solving the simultaneous system of equations, decoupling of fluid pressures in the blocks from the fractures was furnished with a quasi-steady-state flow in the blocks. Analytical solutions were obtained in a radial flow domain using generalized Hankel transform. The real value cannot be gotten because the analytical solutions were infinite series. The real pressure value was obtained by numerical solving the eigenvalue problem. The change law of pressure was studied while the nonlinear parameters and dual-porosity parameters changed, and the plots of typical curves are given. All these result can be applied in well test analysis.展开更多
基金the Major State Basic Research and Development Program of China (No2004CB619102)
文摘The fine grained dual phase (FG-DP) steel with ferrite grains of 2-4.5 μm and martensite islands smaller than 3 μm was obtained through the mechanism of deformation-enhanced ferrite transformation (DEFT). Mechanical properties of the steel were tested at room temperature. The results indicated that with a similar volume fraction of martensite (about 20vol%),FG-DP steel exhibited a superior combination of higher strength and more rapid strain hardening at low strains compared with the coarse-grained dual phase (CG-DP) steel obtained by critical annealing. The combination of higher strength,large elongation,and more rapid strain hardening of FG-DP steel can be attributed to the fine ferrite grain and finely dispersed martensite islands. In addition,the uniformly distributed martensite islands in FG-DP steel have smaller interspacing compared with that of CG-DP steel. So,at the initial plastic deformation stage,the plastic deformation of ferrite was restrained and more pronounced load was transferred from ferrite to martensite. The plastic deformation of martensite in FG-DP steel started earlier.
文摘This paper presents the application of dual-number matrix to the formulation of Jacobian equations of robot with redundancy, the analytical technique that is based on the dual-number matrices, a 3 × 3 matrix with dualnumber elements, and the dual-number transformation method. Dual-number matrices make possible a concise representation of joint parameters. In particular, the method can effectively be used for direct determination of Jacobian matrices. It is shown that the proposed procedure contributes a simplified approach to the formulation of robotic kinematics, dynamics and control system modelling.
基金Supported by the National Natural Science Foundation of China under Grant Nos. 10171026, 60473114,and Anhui Provincial Natural Science Foundation under Grant No. 03046102.
文摘The generalized Ball curves of Wang-Said type with a position parameter L not only unify the Wang-Ball curves and the Said-Ball curves, but also include several useful intermediate curves. This paper presents the dual functionals for the generalized Ball basis of Wang-Said type. The relevant basis transformation formulae are also worked out.
文摘2021 was the first year of the“14th Five-year Plan”and the year in which the“30·60 Goals”were officially implemented.In the first year of the“Dual Carbon Goals”,domestic oil and gas enterprises vigorously expanded their new energy businesses while actively developing their main businesses,bravely shouldered their responsibility for supply guarantee and comprehensively accelerated their green transformation,creating typical experience and practices.
文摘A theorectical expression for the driving force and M_(?) point of martensitic transformation has been proposed.The M_(?) values using this expression are in good agreement with that obtained experimentally.It was found that the values of M_(?) and M_(?) are not only related to the carbon content in martensite,but also to the volume fraction of ferrite.
基金supported by the National Social Science Fund of China[Grant No.21FJYB058].
文摘The pathways to achieving carbon neutrality at the city level are diverse due to varying energy supply and demand conditions.Shanghai faces obstacles such as limited land resources,high costs of renewable energy technologies,and instability of renewable energy.These challenges hinder the city’s efforts to achieve carbon peak and carbon neutrality(dual carbon).Therefore,Shanghai must identify and optimize its development path for renewable energy under the dual carbon goal.We employed the Low Emissions Analysis Platform Shanghai(LEAP-SH)model to simulate the impact of policies,such as industrial upgrading,energy efficiency improvement,energy structure optimization,increased technical innovation on energy,and ecological restoration,on the carbon emission pathways from 2022 to 2060 using five different scenarios.Our results indicate that Shanghai has the potential to achieve carbon neutrality in 2059 by promoting carbon reduction,pollution control,and green expansion.Moreover,we determined that the manufacturing industry;power generation industry;and transportation,storage,and mail services are the three major sectors for emission reduction under the dual carbon goal.Furthermore,the capacity and output of coal-fired power plants will be gradually replaced by offshore wind power in the dual carbon pathway.Finally,this study proposes countermeasures and suggestions for Shanghai to attain the dual carbon goal and high-quality development.
基金supported by the National Key R&D Program of China(2018AAA0102100)the National Natural Science Foundation of China(No.62376287)+3 种基金the International Science and Technology Innovation Joint Base of Machine Vision and Medical Image Processing in Hunan Province(2021CB1013)the Key Research and Development Program of Hunan Province(2022SK2054)the Natural Science Foundation of Hunan Province(No.2022JJ30762,2023JJ70016)the 111 Project under Grant(No.B18059).
文摘Automatic segmentation of medical images provides a reliable scientific basis for disease diagnosis and analysis.Notably,most existing methods that combine the strengths of convolutional neural networks(CNNs)and Transformers have made significant progress.However,there are some limitations in the current integration of CNN and Transformer technology in two key aspects.Firstly,most methods either overlook or fail to fully incorporate the complementary nature between local and global features.Secondly,the significance of integrating the multiscale encoder features from the dual-branch network to enhance the decoding features is often disregarded in methods that combine CNN and Transformer.To address this issue,we present a groundbreaking dual-branch cross-attention fusion network(DCFNet),which efficiently combines the power of Swin Transformer and CNN to generate complementary global and local features.We then designed the Feature Cross-Fusion(FCF)module to efficiently fuse local and global features.In the FCF,the utilization of the Channel-wise Cross-fusion Transformer(CCT)serves the purpose of aggregatingmulti-scale features,and the Feature FusionModule(FFM)is employed to effectively aggregate dual-branch prominent feature regions from the spatial perspective.Furthermore,within the decoding phase of the dual-branch network,our proposed Channel Attention Block(CAB)aims to emphasize the significance of the channel features between the up-sampled features and the features generated by the FCFmodule to enhance the details of the decoding.Experimental results demonstrate that DCFNet exhibits enhanced accuracy in segmentation performance.Compared to other state-of-the-art(SOTA)methods,our segmentation framework exhibits a superior level of competitiveness.DCFNet’s accurate segmentation of medical images can greatly assist medical professionals in making crucial diagnoses of lesion areas in advance.
文摘In order to solve the problems of local maximum modulus extraction and threshold selection in the edge detection of finite resolution digital images, a new wavelet transform based adaptive dual threshold edge detection algorithm is proposed. The local maximum modulus is extracted by linear interpolation in wavelet domain. With the analysis on histogram, the image is filtered with an adaptive dual threshold method, which effectively detects the contours of small structures as well as the boundaries of large objects. A wavelet domain's propagation function is used to further select weak edges. Experimental results have shown the self adaptivity of the threshold to images having the same kind of histogram, and the efficiency even in noise tampered images.
基金supported by a grant from the National High Technology Research and Development Program of China (863 Program) (No.2008AA04A107)supported by a grant from the Major Programs of Guangdong-Hongkong in the Key Domain (No.2009498B21)
文摘Conventional quantization index modulation (QIM) watermarking uses the fixed quantization step size for the host signal.This scheme is not robust against geometric distortions and may lead to poor fidelity in some areas of content.Thus,we proposed a quantization-based image watermarking in the dual tree complex wavelet domain.We took advantages of the dual tree complex wavelets (perfect reconstruction,approximate shift invariance,and directional selectivity).For the case of watermark detecting,the probability of false alarm and probability of false negative were exploited and verified by simulation.Experimental results demonstrate that the proposed method is robust against JPEG compression,additive white Gaussian noise (AWGN),and some kinds of geometric attacks such as scaling,rotation,etc.
基金partially supported by DGRST project04/UR/15-02CMCU program 10G 1503
文摘We study the dual Dunkl-Sonine operator tSk,e on Rd and give expression of tSk,t, using Dunkl multiplier operators on Rd, Next, we study the extremal functions fλ, λ〉 0 related to the Dunkl multiplier operators, and more precisely show that {fλ}λ〉0 converges uniformly to tSk,e(f) as λ→0 Certain examples based on Dunkl-heat and Dunkt-Poisson kernels are provided to illustrate the results.
文摘A new simple and efficient dual tree analytic wavelet transform based on Discrete Cosine Harmonic Wavelet Transform DCHWT (ADCHWT) has been proposed and is applied for signal and image denoising. The analytic DCHWT has been realized by applying DCHWT to the original signal and its Hilbert transform. The shift invariance and the envelope extraction properties of the ADCHWT have been found to be very effective in denoising speech and image signals, compared to that of DCHWT.
基金国家社科基金重大项目“新旧动能转换机制设计与路径选择”(批准号:18Z D A077)南京大学长江三角洲经济社会发展研究中心暨区域经济转型与管理变革协同创新中心联合招标重大项目“长三角区域世界级产业集聚培育和协调发展”(批准号:CYD-2020019)。
文摘The Chinese economy is currently undergoing a digital transformation.New growth drivers are replacing old ones,creating a new development landscape.Countries with strong digital industries will be the first to reap the benefits of digitalization.For China,the transformation to a digital economy is both of inevitability and heterogeneity fueled by dual circulations.Crowded out from more skill-based digitalized sectors,less-skilled labor moves to less digitalized sectors.New capital,industries and technology clusters emerge as new drivers of manufacturing and service sector development.With its large domestic market and industrial competitiveness,China has fostered a new development landscape of“dual circulations”.
基金supported by the National Key R&D Program of China(No.2017YFB0403802)the Technology Cooperation High-tech Industriali-zation Program of Jilin Province of China and the Chinese Academy of Sciences(No.2018SYHZ0023)+2 种基金the Key Technology R&D Program of Jilin Prov-ince of China(No.20180201047YY)the Scientific Research Program of Shanghai Science and Tech-nology Commission(No.18441904300)the Technology Cooperation High-tech Industrializa-tion Program of Jilin Province of China and the Chinese Academy of Sciences(No.2019SYHZ0032)
文摘The majority of existing high-power laser therapeutic instruments employ a single wavelength for a single target;thus,they do not meet the requirements for clinical treatment.Therefore,this study designs an optical system for a dual-wavelength high-power laser therapeutic device with a variable spot size.The waist of the short arm of the optical cavity and the G1G2 parameter(G-parameter equivalent cavity method)is calculated using MATLAB software,the spot size and divergence angle on the lens are calculated using an ABCD matrix,and the distance between the treatment spot at different spot sizes and the transformation lens is calculated in order to design the treatment handpiece.Experiments are conducted to analyze the stability at an output power of 532 nm before beam combination and the power loss after beam combination.The results show that the output power stability of the 532-nm beam varies by less than 2%over 150 min,and the loss of both wavelengths is less than 20%,which meets the clinical requirements of the system.The safety performance can meet the requirements of national general standards for medical electrical safety.The proposed dual-wavelength laser therapy instrument has both visible wave and near-infrared wave characteristics;thus,it can accurately target both superficial vessels and vessels with a larger diameter and deeper position.This therapeutic device has the advantages of simple operation,stable and reliable laser output,high security and strong anti-interference ability,and meets the comprehensive clinical treat-ment demands of vascular diseases.
基金Aerospace Technology Support Foundation (No.HT2001-zjdx)Science and Technology Development Project of Hangzhou City(No.2001121C42)
文摘A dual-CCD simulating human eyes and neck (DSHEN) vision system is putforward. Its structure and principle are introduced. The DSREN vision system can perform somemovements simulating human eyes and neck by means of four rotating joints, and realize preciseobject recognizing and distance measuring in all orientations. The mathematic model of the DSHENvision system is built, and its movement equation is solved. The coordinate error and measureprecision affected by the movement parameters are analyzed by means of intersection measuringmethod. So a theoretic foundation for further research on automatic object recognizing and precisetarget tracking is provided.
文摘The C-Mn and C-Mn-Nb steels were thermo-mechanically processed to develop dual phase steel and to study the effect of controlled rolling on the martensitic hardenability of austenite. The steel specimens were intercritically annealed at 790℃, rolled at that temperature to the reductions of 10%, 23%, and 47% and immediately cooled at different rates. Quantitative metallography was used to construct the microstructure map, which illustrated that increasing deformation progressively reduced the proportion of new ferrite formed at all cooling rates and increased the amount of martensite at fast and intermediate rates. The martensitic hardenability of austenite remaining after all the rolling reductions was plotted as a function of cooling rates. It was observed that for the austenite-martensite conversion efficiencies greater than about 25%, controlled rolling increased the martensitic hardenability of austenite.
文摘In the investigation on fracture mechanics,the potential function was introduced, and the moving differential equation was constructed. By making Laplace and Fourier transformation as well as sine and cosine transformation to moving differential equations and various responses, the dual equation which is constructed from boundary conditions lastly was solved. This method of investigating dynamic crack has become a more systematic one that is used widely. Some problems are encountered when the dynamic crack is studied. After the large investigation on the problems, it is discovered that during the process of mathematic derivation, the method is short of precision, and the derived results in this method are accidental and have no credibility.A model for example is taken to explain the problems existing in initial deriving process of the integral_transformation method of dynamic crack.
文摘A nonlinear dual-porosity model considering a quadratic gradient term is presented. Assuming the pressure difference between matrix and fractures as a primary unknown, to avoid solving the simultaneous system of equations, decoupling of fluid pressures in the blocks from the fractures was furnished with a quasi-steady-state flow in the blocks. Analytical solutions were obtained in a radial flow domain using generalized Hankel transform. The real value cannot be gotten because the analytical solutions were infinite series. The real pressure value was obtained by numerical solving the eigenvalue problem. The change law of pressure was studied while the nonlinear parameters and dual-porosity parameters changed, and the plots of typical curves are given. All these result can be applied in well test analysis.