The K-V beam through an axisymmetric uniform-focusing channel is studied using the particle-core model. The beam halo-chaos is found, and a sample function controller is proposed based on mechanism of halo formation a...The K-V beam through an axisymmetric uniform-focusing channel is studied using the particle-core model. The beam halo-chaos is found, and a sample function controller is proposed based on mechanism of halo formation and strategy of controlling halo-chaos. We perform multiparticle simulation to control the halo by using the sample function controller. The numerical results show that our control method is effective. We also find that the radial ion density changes when the ion beam is in the channel： not only can the halo-chaos and its regeneration be eliminated by using the sample function control method, but also the density uniformity can be found at the beam＇s centre as long as an appropriate control method is chosen.展开更多
In this note, we discuss a class of so-called generalized sampling functions. These functions are defined to be the inverse Fourier transform of a family of piecewise constant functions that are either square integrab...In this note, we discuss a class of so-called generalized sampling functions. These functions are defined to be the inverse Fourier transform of a family of piecewise constant functions that are either square integrable or Lebegue integrable on the real number line. They are in fact the generalization of the classic sinc function. Two approaches of constructing the generalized sampling functions are reviewed. Their properties such as cardinality, orthogonality, and decaying properties are discussed. The interactions of those functions and Hilbert transformer are also discussed.展开更多
Based on the property of sample function,the Woodward synthesis method for separate arrays is improved. The improved method is justified theoretically,and the sample function of the flat-topping and 30 degree cosecant...Based on the property of sample function,the Woodward synthesis method for separate arrays is improved. The improved method is justified theoretically,and the sample function of the flat-topping and 30 degree cosecant-squared space segment pattern on radar phased array antenna is synthesized using it. Through simulation and analysis,it can be used fewer elements to make the same synthesis effect on the pattern with the traditional Woodward method. And if the same number of elements is used,the synthesized pattern using the improved method will have better approach to the sample function,narrower beam width,and higher gain.展开更多
This letter puts forward a method of modeling for the steady-state and small signal dynamic analysis on PWM, quasi-resonant and series/(parallel) resonant switching converters based on pulse-waveform integral approach...This letter puts forward a method of modeling for the steady-state and small signal dynamic analysis on PWM, quasi-resonant and series/(parallel) resonant switching converters based on pulse-waveform integral approach. As an example, PWM and quasi-resonant converters are used to discuss the principle of the approach. The results are compared with those in the relative literatures. Computer aided analysis are made to confirm the correctness.展开更多
Color centers play key roles in,e.g.,solid state lighting and quantum information technology.Here,we describe an approach for predicting the optical line shapes of such emitters based on direct sampling of the underly...Color centers play key roles in,e.g.,solid state lighting and quantum information technology.Here,we describe an approach for predicting the optical line shapes of such emitters based on direct sampling of the underlying autocorrelation functions through molecular dynamics simulations(MD-ACF).The energy landscapes are represented by a machine-learned potential that describes both the ground and excited state landscapes through a single model,guaranteeing size-consistent predictions.We apply this methodology to the(V_(Si)V_(C))_(kk)^(0)divacancy defect in 4H-SiC and demonstrate that at low temperatures,the present MD-ACF approach reproduces results from the traditional generating function approach.Unlike the latter,it is,however,also applicable at high temperatures as it avoids harmonic and parallel-mode approximations and can be applied to study non-crystalline materials.The MD-ACF methodology thus promises to substantially widen the range of computational predictions of the optical properties of color centers and related defects.展开更多
基金Project supported by the National Natural Science Foundation of China （Grant Nos 10247005 and 70071047） and the Scientific Research Foundation of China University of Mining and Technology for the Young （Grant No 2005A037）.
文摘The K-V beam through an axisymmetric uniform-focusing channel is studied using the particle-core model. The beam halo-chaos is found, and a sample function controller is proposed based on mechanism of halo formation and strategy of controlling halo-chaos. We perform multiparticle simulation to control the halo by using the sample function controller. The numerical results show that our control method is effective. We also find that the radial ion density changes when the ion beam is in the channel： not only can the halo-chaos and its regeneration be eliminated by using the sample function control method, but also the density uniformity can be found at the beam＇s centre as long as an appropriate control method is chosen.
文摘In this note, we discuss a class of so-called generalized sampling functions. These functions are defined to be the inverse Fourier transform of a family of piecewise constant functions that are either square integrable or Lebegue integrable on the real number line. They are in fact the generalization of the classic sinc function. Two approaches of constructing the generalized sampling functions are reviewed. Their properties such as cardinality, orthogonality, and decaying properties are discussed. The interactions of those functions and Hilbert transformer are also discussed.
文摘Based on the property of sample function,the Woodward synthesis method for separate arrays is improved. The improved method is justified theoretically,and the sample function of the flat-topping and 30 degree cosecant-squared space segment pattern on radar phased array antenna is synthesized using it. Through simulation and analysis,it can be used fewer elements to make the same synthesis effect on the pattern with the traditional Woodward method. And if the same number of elements is used,the synthesized pattern using the improved method will have better approach to the sample function,narrower beam width,and higher gain.
文摘This letter puts forward a method of modeling for the steady-state and small signal dynamic analysis on PWM, quasi-resonant and series/(parallel) resonant switching converters based on pulse-waveform integral approach. As an example, PWM and quasi-resonant converters are used to discuss the principle of the approach. The results are compared with those in the relative literatures. Computer aided analysis are made to confirm the correctness.
基金funding from the Swedish Research Council(Nos.2020-04935 and 2021-05072)as well as computational resources provided by the National Academic Infrastructure for Supercomputing in Sweden at NSC,PDCC3SE partially funded by the Swedish Research Council through grant agreement No.2022-06725+1 种基金as well as the Berzelius resource provided by the Knut and Alice Wallenberg Foundation at NSC.Parts of the computations were performed on resources provided by UNINETT Sigma2-the National Infrastructure for High-Performance Computing and Data Storage in Norway.C.L.acknowledges the support provided by the Research Council of Norway and the University of Oslo through the research project QuTe(no.325573,FriPro ToppForsk-program)funding from the Swedish Strategic Research Foundation through a Future Research Leader program(FFL21-0129).
文摘Color centers play key roles in,e.g.,solid state lighting and quantum information technology.Here,we describe an approach for predicting the optical line shapes of such emitters based on direct sampling of the underlying autocorrelation functions through molecular dynamics simulations(MD-ACF).The energy landscapes are represented by a machine-learned potential that describes both the ground and excited state landscapes through a single model,guaranteeing size-consistent predictions.We apply this methodology to the(V_(Si)V_(C))_(kk)^(0)divacancy defect in 4H-SiC and demonstrate that at low temperatures,the present MD-ACF approach reproduces results from the traditional generating function approach.Unlike the latter,it is,however,also applicable at high temperatures as it avoids harmonic and parallel-mode approximations and can be applied to study non-crystalline materials.The MD-ACF methodology thus promises to substantially widen the range of computational predictions of the optical properties of color centers and related defects.
