The discovery of ＂twin quasi-stellar objects＂ arose interests among astronomers and astrophysicists to study gravitational leasing problem. Deviation of light from straight path is caused by the presence of massive ...The discovery of ＂twin quasi-stellar objects＂ arose interests among astronomers and astrophysicists to study gravitational leasing problem. Deviation of light from straight path is caused by the presence of massive objects, i.e., the presence of gravitational field according to the general theory of relativity. It is shown that the low energy effective field theory on D-branes is of the Born-Infeld type. In this work a Born-Infeld type gravitational field is pasttflated. An explicit representation of the angular deviation of light path is derived based on the space time metric in the Born-Infeld theory.展开更多
The accurate monitoring of optical thin-film thickness is a key technique for depositing optical thin-film. For existing coating equipments, which are low precision and automation level on monitoring thin-film thickne...The accurate monitoring of optical thin-film thickness is a key technique for depositing optical thin-film. For existing coating equipments, which are low precision and automation level on monitoring thin-film thickness, a new photoelectric control and analysis system has been developed. In the new system, main techniques include a photoelectric system with dual-light path, a dual-lock-phase circuit system and a comprehensive digital processing-control-analysis system.The test results of new system show that the static and dynamic stabilities and the control precision of thin-film thickness are extremely increased. The standard deviation of thin-film thickness, which indicates the duplication of thin-film thickness monitoring, is equal to or less than 0.72%. The display resolution limit on reflectivity is 0.02 %. In the system, the linearity of drift is very high, and the static drift ratio approaches zero.展开更多
In this paper, we study the estimation variance of a set of global illumination algorithms based on indirect light path reuse. These algorithms usually contain two passes -- in the first pass, a small number of indire...In this paper, we study the estimation variance of a set of global illumination algorithms based on indirect light path reuse. These algorithms usually contain two passes -- in the first pass, a small number of indirect light samples are generated and evaluated, and they are then reused by a large number of reconstruction samples in the second pass. Our analysis shows that the covariance of the reconstruction samples dominates the estimation variance under high reconstruction rates and increasing the reconstruction rate cannot effectively reduce the covariance. We also find that the covariance represents to what degree the indirect light samples are reused during reconstruction. This analysis motivates us to design a heuristic approximating the covariance as well as an adaptive sampling scheme based on this heuristic to reduce the rendering variance. We validate our analysis and adaptive sampling scheme in the indirect light field reconstruction algorithm and the axis-aligned filtering algorithm for indirect lighting. Experiments are in accordance with our analysis and show that rendering artifacts can be greatly reduced at a similar computational cost.展开更多
In a recent paper we have studied the Hamiltonian and path integral quantizations of the conformally gauge-fixed Polyakov D1 brane action in the instant-form of dynamics using the equal world-sheet time framework on t...In a recent paper we have studied the Hamiltonian and path integral quantizations of the conformally gauge-fixed Polyakov D1 brane action in the instant-form of dynamics using the equal world-sheet time framework on the hyperplanes defined by the world- sheet time . In the present work we quantize the same theory in the equal light-cone world-sheet time framework, on the hyperplanes of the light-front defined by the light-cone world-sheet time , using the standard constraint quantization techniques in the Hamiltonian and path integral formulations. The light-front theory is seen to be a constrained system in the sense of Dirac, which is in contrast to the corresponding case of the instant-form theory, where the theory remains unconstrained in the sense of Dirac. The light-front theory is seen to possess a set of twenty six primary second-class contraints. In the present work Hamiltonian and path integral quantizations of this theory are studied on the light-front.展开更多
In the present work we study the Hamiltonian, path integral and BRST formulations of the Chern-Simons-Higgs theory in two-space one-time dimensions, in the so-called broken symmetry phase of the Higgs potential (where...In the present work we study the Hamiltonian, path integral and BRST formulations of the Chern-Simons-Higgs theory in two-space one-time dimensions, in the so-called broken symmetry phase of the Higgs potential (where the phase φ(xμ) of the complex matter field Φ(xμ) carries the charge degree of freedom of the complex matter field and is akin to the Goldstone boson) on the light-front (i.e., on the hyperplanes defined by the fixed light-cone time). The theory is seen to possess a set of first-class constraints and the local vector gauge symmetry. The theory being gauge-invariant is quantized under appropriate gauge-fixing conditions. The explicit Hamiltonian and path integral quantization is achieved under the above light-cone gauges. The Heisenberg equations of motion of the system are derived for the physical degrees of freedom of the system. Finally the BRST quantization of the system is achieved under appropriate BRST gauge-fixing, where the BRST symmetry is maintained even under the BRST light-cone gauge-fixing.展开更多
Recently we have studied the instant-form quantization (IFQ) of the conformally gauge-fixed Polyakov D1 brane action with and without a scalar dilaton field using the Hamiltonian and path integral formulations in the ...Recently we have studied the instant-form quantization (IFQ) of the conformally gauge-fixed Polyakov D1 brane action with and without a scalar dilaton field using the Hamiltonian and path integral formulations in the equal world-sheet time framework on the hyperplanes defined by the world- sheet time σ0=τ=constant . The light-front quantization (LFQ) of this theory without a scalar dilaton field has also been studied by us recently. In the present work we study the LFQ of this theory in the equal light-cone world-sheet time framework, on the hyperplanes of the light-front defined by the light-cone world-sheet time σ+=τ+σ=constant , using the Hamiltonian and path integral formulations. The light-front theory is seen to be a constrained system in the sense of Dirac. The light-front theory is seen to possess a set of twenty seven primary second-class contraints. In the present work Hamiltonian and path integral quantizations of this theory are studied on the light-front.展开更多
Recently we have studied the instant-form quantization (IFQ) and the light-front quantization (LFQ) of the conformally gauge-fixed Polyakov D1 brane action using the Hamiltonian and path integral formulations. The IFQ...Recently we have studied the instant-form quantization (IFQ) and the light-front quantization (LFQ) of the conformally gauge-fixed Polyakov D1 brane action using the Hamiltonian and path integral formulations. The IFQ is studied in the equal world-sheet time framework on the hyperplanes defined by the world-sheet time σ0=τ=constant and the LFQ in the equal light-cone world-sheet time framework, on the hyperplanes of the light-front defined by the light-cone world-sheet time σ+= (τ+σ) =constant. The light-front theory is seen to be a constrained system in the sense of Dirac in contrast to the instant-form theory. However, owing to the gauge anomalous nature of these theories, both of these theories are seen to lack the usual string gauge symmetries defined by the world-sheet reparametrization invariance (WSRI) and the Weyl invariance (WI). In the present work we show that these theories when considered in the presence of background gauge fields such as the NSNS 2-form gauge field Bαβ(σ,τ) or in the presence of U(1) gauge field Aα(σ,τ) and the constant scalar axion field C(σ,τ), then they are seen to possess the usual string gauge symmetries (WSRI and WI). In fact, these background gauge fields are seen to behave as the Wess-Zumino or Stueckelberg fields and the terms containing these fields are seen to behave as Wess-Zumino or Stueckelberg terms for these theories.展开更多
The Chern-Simons theory in two-space one-time dimensions is quantized on the light-front under appropriate gauge-fixing conditions using the Hamiltonian, path integral and BRST formulations.
随着机器视觉技术的快速发展,智能焊接技术在机械制造领域中的应用越来越广泛。通过结构光相机建立三维模型,开发出无需示教的机器人自主焊接方法,可在铸钉辊的复杂几何轮廓上实现高精度焊接路径的自动生成。首先,对三维重建之后的点云...随着机器视觉技术的快速发展,智能焊接技术在机械制造领域中的应用越来越广泛。通过结构光相机建立三维模型,开发出无需示教的机器人自主焊接方法,可在铸钉辊的复杂几何轮廓上实现高精度焊接路径的自动生成。首先,对三维重建之后的点云使用曲面拟合、直通滤波、区域生长和边缘提取等算法进行分割和预处理。然后,对陶瓷柱的边缘点云和质心建立数学模型,获得焊接点位。最后,使用主成分分析(Principal Component Analysis,PCA)算法,对三维空间中的焊接点位进行最优路径求取,并自主规划出整个曲面工件的焊接路径,样本数据显示,系统整体误差小于0.5 mm。工程试验结果表明,焊缝外观无明显缺陷,满足铸钉辊活性气体保护电弧焊(Metal Active Gas arc welding,MAG焊)工艺的自主焊接生产需要。该结果对具有一定曲面的铸钉辊表面自主堆焊工程应用具有一定的指导意义和参考价值。展开更多
文摘The discovery of ＂twin quasi-stellar objects＂ arose interests among astronomers and astrophysicists to study gravitational leasing problem. Deviation of light from straight path is caused by the presence of massive objects, i.e., the presence of gravitational field according to the general theory of relativity. It is shown that the low energy effective field theory on D-branes is of the Born-Infeld type. In this work a Born-Infeld type gravitational field is pasttflated. An explicit representation of the angular deviation of light path is derived based on the space time metric in the Born-Infeld theory.
基金Sponsored by the Ordnance Industry Scientific Research Fund(ZZ9682-3).
文摘The accurate monitoring of optical thin-film thickness is a key technique for depositing optical thin-film. For existing coating equipments, which are low precision and automation level on monitoring thin-film thickness, a new photoelectric control and analysis system has been developed. In the new system, main techniques include a photoelectric system with dual-light path, a dual-lock-phase circuit system and a comprehensive digital processing-control-analysis system.The test results of new system show that the static and dynamic stabilities and the control precision of thin-film thickness are extremely increased. The standard deviation of thin-film thickness, which indicates the duplication of thin-film thickness monitoring, is equal to or less than 0.72%. The display resolution limit on reflectivity is 0.02 %. In the system, the linearity of drift is very high, and the static drift ratio approaches zero.
基金This work was supported in part by the National Natural Science Foundation of China under Grant Nos. 61472352, 61379070, and 61272305, and the National High Technology Research and Development 863 Program of China under Grant No. 2012AA010903.
文摘In this paper, we study the estimation variance of a set of global illumination algorithms based on indirect light path reuse. These algorithms usually contain two passes -- in the first pass, a small number of indirect light samples are generated and evaluated, and they are then reused by a large number of reconstruction samples in the second pass. Our analysis shows that the covariance of the reconstruction samples dominates the estimation variance under high reconstruction rates and increasing the reconstruction rate cannot effectively reduce the covariance. We also find that the covariance represents to what degree the indirect light samples are reused during reconstruction. This analysis motivates us to design a heuristic approximating the covariance as well as an adaptive sampling scheme based on this heuristic to reduce the rendering variance. We validate our analysis and adaptive sampling scheme in the indirect light field reconstruction algorithm and the axis-aligned filtering algorithm for indirect lighting. Experiments are in accordance with our analysis and show that rendering artifacts can be greatly reduced at a similar computational cost.
文摘In a recent paper we have studied the Hamiltonian and path integral quantizations of the conformally gauge-fixed Polyakov D1 brane action in the instant-form of dynamics using the equal world-sheet time framework on the hyperplanes defined by the world- sheet time . In the present work we quantize the same theory in the equal light-cone world-sheet time framework, on the hyperplanes of the light-front defined by the light-cone world-sheet time , using the standard constraint quantization techniques in the Hamiltonian and path integral formulations. The light-front theory is seen to be a constrained system in the sense of Dirac, which is in contrast to the corresponding case of the instant-form theory, where the theory remains unconstrained in the sense of Dirac. The light-front theory is seen to possess a set of twenty six primary second-class contraints. In the present work Hamiltonian and path integral quantizations of this theory are studied on the light-front.
文摘In the present work we study the Hamiltonian, path integral and BRST formulations of the Chern-Simons-Higgs theory in two-space one-time dimensions, in the so-called broken symmetry phase of the Higgs potential (where the phase φ(xμ) of the complex matter field Φ(xμ) carries the charge degree of freedom of the complex matter field and is akin to the Goldstone boson) on the light-front (i.e., on the hyperplanes defined by the fixed light-cone time). The theory is seen to possess a set of first-class constraints and the local vector gauge symmetry. The theory being gauge-invariant is quantized under appropriate gauge-fixing conditions. The explicit Hamiltonian and path integral quantization is achieved under the above light-cone gauges. The Heisenberg equations of motion of the system are derived for the physical degrees of freedom of the system. Finally the BRST quantization of the system is achieved under appropriate BRST gauge-fixing, where the BRST symmetry is maintained even under the BRST light-cone gauge-fixing.
文摘Recently we have studied the instant-form quantization (IFQ) of the conformally gauge-fixed Polyakov D1 brane action with and without a scalar dilaton field using the Hamiltonian and path integral formulations in the equal world-sheet time framework on the hyperplanes defined by the world- sheet time σ0=τ=constant . The light-front quantization (LFQ) of this theory without a scalar dilaton field has also been studied by us recently. In the present work we study the LFQ of this theory in the equal light-cone world-sheet time framework, on the hyperplanes of the light-front defined by the light-cone world-sheet time σ+=τ+σ=constant , using the Hamiltonian and path integral formulations. The light-front theory is seen to be a constrained system in the sense of Dirac. The light-front theory is seen to possess a set of twenty seven primary second-class contraints. In the present work Hamiltonian and path integral quantizations of this theory are studied on the light-front.
文摘Recently we have studied the instant-form quantization (IFQ) and the light-front quantization (LFQ) of the conformally gauge-fixed Polyakov D1 brane action using the Hamiltonian and path integral formulations. The IFQ is studied in the equal world-sheet time framework on the hyperplanes defined by the world-sheet time σ0=τ=constant and the LFQ in the equal light-cone world-sheet time framework, on the hyperplanes of the light-front defined by the light-cone world-sheet time σ+= (τ+σ) =constant. The light-front theory is seen to be a constrained system in the sense of Dirac in contrast to the instant-form theory. However, owing to the gauge anomalous nature of these theories, both of these theories are seen to lack the usual string gauge symmetries defined by the world-sheet reparametrization invariance (WSRI) and the Weyl invariance (WI). In the present work we show that these theories when considered in the presence of background gauge fields such as the NSNS 2-form gauge field Bαβ(σ,τ) or in the presence of U(1) gauge field Aα(σ,τ) and the constant scalar axion field C(σ,τ), then they are seen to possess the usual string gauge symmetries (WSRI and WI). In fact, these background gauge fields are seen to behave as the Wess-Zumino or Stueckelberg fields and the terms containing these fields are seen to behave as Wess-Zumino or Stueckelberg terms for these theories.
文摘The Chern-Simons theory in two-space one-time dimensions is quantized on the light-front under appropriate gauge-fixing conditions using the Hamiltonian, path integral and BRST formulations.
文摘随着机器视觉技术的快速发展,智能焊接技术在机械制造领域中的应用越来越广泛。通过结构光相机建立三维模型,开发出无需示教的机器人自主焊接方法,可在铸钉辊的复杂几何轮廓上实现高精度焊接路径的自动生成。首先,对三维重建之后的点云使用曲面拟合、直通滤波、区域生长和边缘提取等算法进行分割和预处理。然后,对陶瓷柱的边缘点云和质心建立数学模型,获得焊接点位。最后,使用主成分分析(Principal Component Analysis,PCA)算法,对三维空间中的焊接点位进行最优路径求取,并自主规划出整个曲面工件的焊接路径,样本数据显示,系统整体误差小于0.5 mm。工程试验结果表明,焊缝外观无明显缺陷,满足铸钉辊活性气体保护电弧焊(Metal Active Gas arc welding,MAG焊)工艺的自主焊接生产需要。该结果对具有一定曲面的铸钉辊表面自主堆焊工程应用具有一定的指导意义和参考价值。
