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Complex coordinate rotation method based on gradient optimization
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作者 白志达 钟振祥 +1 位作者 严宗朝 史庭云 《Chinese Physics B》 SCIE EI CAS CSCD 2021年第2期257-261,共5页
In atomic,molecular,and nuclear physics,the method of complex coordinate rotation is a widely used theoretical tool for studying resonant states.Here,we propose a novel implementation of this method based on the gradi... In atomic,molecular,and nuclear physics,the method of complex coordinate rotation is a widely used theoretical tool for studying resonant states.Here,we propose a novel implementation of this method based on the gradient optimization(CCR-GO).The main strength of the CCR-GO method is that it does not require manual adjustment of optimization parameters in the wave function;instead,a mathematically well-defined optimization path can be followed.Our method is proven to be very efficient in searching resonant positions and widths over a variety of few-body atomic systems,and can significantly improve the accuracy of the results.As a special case,the CCR-GO method is equally capable of dealing with bound-state problems with high accuracy,which is traditionally achieved through the usual extreme conditions of energy itself. 展开更多
关键词 complex coordinate rotation method resonant state metastable state gradient optimization
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A key factor to the spin parameter of uniformly rotating compact stars: crust structure
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作者 Bin Qi Nai-Bo Zhang +2 位作者 Bao-Yuan Sun Shou-Yu Wang Jian-Hua Gao 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2016年第4期63-70,共8页
We study the dimensionless spin parameter j ≡ cJ/(GM2) of different kinds of uniformly rotating compact stars, including traditional neutron stars, hyperonic neutron stars and hybrid stars, based on relativistic me... We study the dimensionless spin parameter j ≡ cJ/(GM2) of different kinds of uniformly rotating compact stars, including traditional neutron stars, hyperonic neutron stars and hybrid stars, based on relativistic mean field theory and the MIT bag model. It is found that j ~ 0.7, which had been suggested in traditional neutron stars, is sustained for hyperonic neutron stars and hybrid stars with M 〉 0.5 MG. Not the interior but rather the crust structure of the stars is a key factor to determine jmax for three kinds of selected compact stars. Furthermore, a universal formula j = 0.63(f/fK) -- 0.42(f/fK)2 + 0.48(f/fK)z is suggested to determine the spin parameter at any rotational frequency f smaller than the Keplerian frequency fK. 展开更多
关键词 stars: neutron -- stars: rotation -- spin parameter-- equation of state -- methods: numerical
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A NOTE ON MARCINKIEWICZ INTEGRALS WITH H^1 KERNELS 被引量:7
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作者 徐罕 陈杰诚 应益明 《Acta Mathematica Scientia》 SCIE CSCD 2003年第1期133-138,共6页
This paper shows that for Ω∈ H1(Sn-1), Marcinkiewicz integral operator μΩ is Lp(Rn) bounded for 1 < p <∞, which improves some known results.
关键词 Marcinkiewicz integral rotation method Hardy space
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Quasi-real-time simulation of rotating drum using discrete element method with parallel GPU computing 被引量:18
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作者 Ji Xu Huabiao Oi +7 位作者 Xiaojian Fang Liqiang Lu Wei Ge Xiaowei Wang Ming xu Feiguo Chen xianfeng He Jinghai Li 《Particuology》 SCIE EI CAS CSCD 2011年第4期446-450,共5页
Real-time simulation of industrial equipment is a huge challenge nowadays. The high performance and fine-grained parallel computing provided by graphics processing units (GPUs) bring us closer to our goals. In this ... Real-time simulation of industrial equipment is a huge challenge nowadays. The high performance and fine-grained parallel computing provided by graphics processing units (GPUs) bring us closer to our goals. In this article, an industrial-scale rotating drum is simulated using simplified discrete element method (DEM) without consideration of the tangential components of contact force and particle rotation. A single GPU is used first to simulate a small model system with about 8000 particles in real-time, and the simulation is then scaled up to industrial scale using more than 200 GPUs in a 1 D domain-decomposition parallelization mode. The overall speed is about 1/11 of the real-time. Optimization of the communication part of the parallel GPU codes can speed up the simulation further, indicating that such real-time simulations have not only methodological but also industrial implications in the near future. 展开更多
关键词 rotating drumReal-time Discrete element method (DEM) Speedup GPU
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Low-Complexity DOA Estimation of Noncircular Signals for Coprime Sensor Arrays 被引量:1
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作者 ZHAI Hui CHEN Weiyang +1 位作者 ZHANG Xiaofei ZHENG Wang 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI CSCD 2019年第4期599-608,共10页
This paper presents a low?complexity method for the direction?of?arrival(DOA)estimation of noncircular signals for coprime sensor arrays.The noncircular property is exploited to improve the performance of DOA estimati... This paper presents a low?complexity method for the direction?of?arrival(DOA)estimation of noncircular signals for coprime sensor arrays.The noncircular property is exploited to improve the performance of DOA estimation.To reduce the computational complexity,the rotational invariance propagator method(RIPM)is included in the algorithm.First,the extended array output is reconstructed by combining the array output and its conjugated counterpart.Then,the RIPM is utilized to obtain two sets of DOA estimates for two subarrays.Finally,the true DOAs are estimated by combining the consistent results of the two subarrays.This illustrates the potential gain that both noncircularity and coprime arrays provide when considered together.The proposed algorithm has a lower computational complexity and a better DOA estimation performance than the standard estimation of signal parameters by the rotational invariance technique and Capon algorithm.Numerical simulation results illustrate the effectiveness and superiority of the proposed algorithm. 展开更多
关键词 sensor array direction of arrival estimation coprime sensor arrays noncircular signals rotational invariance propagator method
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Discrete element method study of shear-driven granular segregation in a slowly rotating horizontal drum 被引量:4
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作者 Ram Chand Sithi V. Muniandy +1 位作者 Chiow San Wong Jasbir Singh 《Particuology》 SCIE EI CAS CSCD 2017年第3期89-94,共6页
Segregation and mixing of granular materials are complex processes and are not fully understood. Motivated by industrial need, we performed a simulation using the discrete element method to study size segregation of a... Segregation and mixing of granular materials are complex processes and are not fully understood. Motivated by industrial need, we performed a simulation using the discrete element method to study size segregation of a binary mixture of granular particles in a horizontal rotating drum. Particles of two dif- ferent sizes were poured into the drum until it was 50% full. Shear-driven segregation was induced by rotating the side-plates of the drum in the opposite direction to that of the cylindrical wall. We found that radial segregation diminished in these systems but did not completely vanish. In an ordinary rotating drum, a radial core of smaller particles is formed in the center of the drum, surrounded by larger revolving particles. In our system, however, the smaller particles were found to migrate toward the side-plates. The shear from anti-spinning side-plates reduces the voidage and increases the bulk density. As such, smaller particles in the mixer tend to move to denser regions. We varied the shear by changing the coefficient of friction on the side-plates to study the influence of shear rate on this migration. We also compared the extent of radial segregation with stationary side-plates and with side-plates moving in different angular directions. 展开更多
关键词 Granular flow Discrete element method Segregation Side-wall shear rotating drum Mixing
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A note on parameterized Marcinkiewicz integrals with variable kernels
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作者 WANG Hui ZHANG Chun-jie 《Applied Mathematics(A Journal of Chinese Universities)》 SCIE CSCD 2009年第3期315-320,共6页
In this paper,the parameterized Marcinkiewicz integrals with variable kernels defined by μΩ^ρ(f)(x)=(∫0^∞│∫│1-y│≤t Ω(x,x-y)/│x-y│^n-p f(y)dy│^2dt/t1+2p)^1/2 are investigated.It is proved that ... In this paper,the parameterized Marcinkiewicz integrals with variable kernels defined by μΩ^ρ(f)(x)=(∫0^∞│∫│1-y│≤t Ω(x,x-y)/│x-y│^n-p f(y)dy│^2dt/t1+2p)^1/2 are investigated.It is proved that if Ω∈ L∞(R^n) × L^r(S^n-1)(r〉(n-n1p'/n) is an odd function in the second variable y,then the operator μΩ^ρ is bounded from L^p(R^n) to L^p(R^n) for 1 〈 p ≤ max{(n+1)/2,2}.It is also proved that,if Ω satisfies the L^1-Dini condition,then μΩ^ρ is of type(p,p) for 1 〈 p ≤ 2,of the weak type(1,1) and bounded from H1 to L1. 展开更多
关键词 parameterized Marcinkiewicz integral variable kernel rotation method
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Current measurement method based on magneto-optic rotation effect
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作者 SHUI Huasheng RONG Yufei +1 位作者 JIANG Chunlei DONG Taiji 《Optoelectronics Letters》 EI 2023年第9期563-569,共7页
Aiming at the approximate measurement of magnetic rotation angle in optical current sensor based on light intensity detection mode,this paper proposes a current measurement method based on triangular constant transfor... Aiming at the approximate measurement of magnetic rotation angle in optical current sensor based on light intensity detection mode,this paper proposes a current measurement method based on triangular constant transformation to reconstruct magnetic rotation angle,so as to avoid the large current measurement error caused by the approximate measurement of the magnetic rotation angle.By extracting the direct current(DC)component and the alternating current(AC)component of the light intensity signal detected by the photoelectric detector(PD),the sine signal containing the magnetic rotation angle is directly obtained by dividing the two components,and then the triangular identity transformation method is used to linearly demodulate the magnetic rotation angle and reconstruct the current waveform.The experimental results show that the relative error of current measurement does not exceed 1.40%in the current range of 0.05—0.50 A,which is less than the approximate linear measurement(ALM)method,and the magnetic rotation angle and the current have a good linear relationship. 展开更多
关键词 Current measurement method based on magneto-optic rotation effect
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Method for Improving Transverse Wall Thickness Precision of Seamless Steel Tube Based on Tube Rotation 被引量:1
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作者 Yong-zheng JIANG Hua-ping TANG 《Journal of Iron and Steel Research(International)》 SCIE EI CAS CSCD 2015年第10期924-930,共7页
The tube rotation method (TRM) refers to the rotational movement of steel tube about its axis as well as translation in rolling direction in stretch reducing rolling process. The influence of the TRM on transverse w... The tube rotation method (TRM) refers to the rotational movement of steel tube about its axis as well as translation in rolling direction in stretch reducing rolling process. The influence of the TRM on transverse wall thickness precision of seamless steel tube was studied. Thickness distribution of the TRM was obtained by superimposing the thickened amount of single pass rolling. Results show that the TRM can effectively improve the evenness of thickness distribution. In order to analyze the influence mechanism of the TRM, the finite element method was adopted to simulate the thickness distribution in stretch reduction process. Results show that the TRM changes the roundtrip flow between two fix places of conventional stretch reducing and inhibits the directional accumulation of metal. In addition, the TRM has a correction effect on thickness cusp. All these advantages of the TRM help to improve the transverse wall thickness precision of seamless steel tube. 展开更多
关键词 seamless tube stretch reducing transverse unevenness tube rotation method
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Sensorless Control of Permanent Magnet Synchronous Motor in Full Speed Range 被引量:2
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作者 Dingdou Wen Wei Wang Yang Zhang 《Chinese Journal of Electrical Engineering》 CSCD 2022年第2期97-107,共11页
Aiming at resolving the limitation of the speed regulation range of sensorless control technology,a new composite sensorless control strategy is proposed to realize a control method for a permanent magnet synchronous ... Aiming at resolving the limitation of the speed regulation range of sensorless control technology,a new composite sensorless control strategy is proposed to realize a control method for a permanent magnet synchronous motor(PMSM)in full speed range.In the medium-and high-speed range,the improved new sliding mode observer method is used to estimate the motor speed and rotor position information.In the zero and low speed range,in order to avoid the defects of the sliding mode method,the rotating high-frequency voltage signal injection method is used.When switching between low,medium,and high speed,the fuzzy control algorithm is adopted to achieve smooth transitions.The simulation experiment results show that the hybrid mode combining the sliding mode observer and rotating high-frequency voltage injection methods,can effectively reduce the jitter in the algorithm switching process,and realize the smooth control of a PMSM in full speed range. 展开更多
关键词 PMSM full speed range rotating high-frequency voltage signal injection method sliding mode observer method fuzzy control
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Ideal proportional navigation for exoatmospheric interception 被引量:17
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作者 Li Kebo Zhang Taotao Chen Lei 《Chinese Journal of Aeronautics》 SCIE EI CAS CSCD 2013年第4期976-985,共10页
Ideal proportional navigation (IPN) is a natural choice for exoatmospheric interception for its mighty capture capability and ease of implementation. The closed-form solution of two- dimensional ideal proportional n... Ideal proportional navigation (IPN) is a natural choice for exoatmospheric interception for its mighty capture capability and ease of implementation. The closed-form solution of two- dimensional ideal proportional navigation was conducted in previous public literature, whereas the practical interception happens in the three-dimensional space. A novel set of relative dynamic equations is adopted in this paper, which is with the advantage of decoupling relative motion in the instantaneous rotation plane of the line of sight from the rotation of this plane. The dimension-reduced IPN is constructed in this instantaneous plane, which functions as a three-dimensional guidance law. The trajectory features of dimension-reduced IPN are explored, and the capture regions of dimension-reduced IPN with limited acceleration against nonmaneuvering and maneuvering targets are analyzed by using phase plane method. It is proved that the capture capability of IPN is much stronger than true proportional navigation (TPN), no matter the target maneuvers or not. Finally, simulation results indicate that IPN is more effective than TPN in exoatmospheric interception scenarios. 展开更多
关键词 Capture region Exoatmospheric interception Ideal proportional navigation Instantaneous rotation plane of line of sight Missile guidance Phase plane method
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Computer assessment of the composition of a generic wound by image processing
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作者 Rohit Nayak Pramod Kumar Ramesh R.Galigekere 《Plastic and Aesthetic Research》 2015年第1期261-265,共5页
Aim:This paper addresses the assessment of the composition of a general wound,in terms of all identifiable categories of tissue and pigmentation in an attempt to improve accuracy in assessing and monitoring wound heal... Aim:This paper addresses the assessment of the composition of a general wound,in terms of all identifiable categories of tissue and pigmentation in an attempt to improve accuracy in assessing and monitoring wound health.Materials and Methods:A knowledgebase of clusters was built into the hue,saturation and intensity(HSI)color space and then used for assessing wound composition.Based on the observation that the clusters are fairly distinct,two different algorithms,that is,Mahalanobis distance(MD)based and the rotated coordinate system(RCS)method,were used for classification.These methods exploit the shape,spread,and orientation of each cluster.Results:The clusters in the HSI color space,built from about 9,000(calibrated)pixels from 48 images of various wound beds,showed 8 fairly distinct regions.The inter-cluster distances were consistent with the visual appearance.The efficacy of the MD and RCS based methods in 120 experiments taken from a set of 15 test images(in terms of average percent-match)was found to be 91.55 and 93.71,respectively.Conclusion:Our investigations established eight categories of tissue and pigmentation in wound beds.These findings help to determine the stage of wound healing more accurately and comprehensively than typically permitted through use of the 4-color model reported in the literature for addressing specific wound types. 展开更多
关键词 Wound composition color-image processing HUE saturation and intensity model classification Mahalanobis distance rotated coordinate system method
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