The purpose of the current article is to study the H^(1)-stability for all positive time of the linearly extrapolated BDF2 timestepping scheme for the magnetohydrodynamics and Boussinesq equations.Specifically,we disc...The purpose of the current article is to study the H^(1)-stability for all positive time of the linearly extrapolated BDF2 timestepping scheme for the magnetohydrodynamics and Boussinesq equations.Specifically,we discretize in time using the linearly backward differentiation formula,and by employing both the discrete Gronwall lemma and the discrete uniform Gronwall lemma,we establish that each numerical scheme is uniformly bounded in the H^(1)-norm.展开更多
As the thickness of an SOI layer varies,a minimum breakdown voltage is reached when the thickness is about 2μm. The vertical electric field of the SOI LDMOS with a drift region which is vertically linearly graded is ...As the thickness of an SOI layer varies,a minimum breakdown voltage is reached when the thickness is about 2μm. The vertical electric field of the SOI LDMOS with a drift region which is vertically linearly graded is constant. The vertically linearly graded concentration drift can be achieved by impurity implanting followed by thermal diffusion. In this way,the vertical breakdown voltage of SOI LDMOS with 2μm thickness SOI layer can be improved by 43%. The on-state resistance is lowered by 24 % because of the higher impurity concentration of the SOI surface.展开更多
A novel 2D analytical model for the doping profile of the bulk silicon RESURF LDMOS drift region is proposed. According to the proposed model, to obtain good performance, the doping profile in the total drift region o...A novel 2D analytical model for the doping profile of the bulk silicon RESURF LDMOS drift region is proposed. According to the proposed model, to obtain good performance, the doping profile in the total drift region of a RESURF LDMOS with a field plate should be piecewise linearly graded. The breakdown voltage of the proposed RESURF LDMOS with a piecewise linearly graded doping drift region is improved by 58. 8%, and the specific on-resistance is reduced by 87. 4% compared with conventional LDMOS. These results are verified by the two-dimensional process simulator Tsuprem-4 and the device simulator Medici.展开更多
A ring R is called linearly McCoy if whenever linear polynomials f（x）, g（x） e R[x]／{0） satisfy f（x）g（x） ： O, then there exist nonzero elements r, s ∈ R such that f（x）r ： sg（x） =0. For a ring endomorph...A ring R is called linearly McCoy if whenever linear polynomials f（x）, g（x） e R[x]／{0） satisfy f（x）g（x） ： O, then there exist nonzero elements r, s ∈ R such that f（x）r ： sg（x） =0. For a ring endomorphism α, we introduced the notion of α-skew linearly McCoy rings by considering the polynomials in the skew polynomial ring R[x; α] in place of the ring R[x]. A number of properties of this generalization are established and extension properties of α-skew linearly McCoy rings are given.展开更多
This report describes an equivalent doping profile transformation method with which the avalanche breakdown voltage of the asymmetric linearly graded junction was analytically predicted.The maximum breakdown voltage a...This report describes an equivalent doping profile transformation method with which the avalanche breakdown voltage of the asymmetric linearly graded junction was analytically predicted.The maximum breakdown voltage and the different depletion layer extension on the diffused side and substrate side are demonstrated in the report.The report shows the equivalent doping profile method is valid to predict the breakdown voltage of the complex P N junction.The analytical results agree with the experimental breakdown voltage in comparison with the abrupt junction and symmetric linearly graded junction approximations.展开更多
AIM: To compare the outcomes of hand-sewn(HS) and linearly stapled(LS) esophagogastric anastomosis for esophageal cancer.METHODS: Before beginning this study, a rigorous protocol was established according to the recom...AIM: To compare the outcomes of hand-sewn(HS) and linearly stapled(LS) esophagogastric anastomosis for esophageal cancer.METHODS: Before beginning this study, a rigorous protocol was established according to the recommendations of the Cochrane Collaboration. Databases and references were searched for all randomizedcontrolled trials and comparative clinical studies that compared LS with HS esophagogastric anastomosis for esophageal cancer. The primary outcomes compared were anastomotic leak and stricture. Subgroup analyses were performed according to site of anastomosis.RESULTS: Fifteen studies were used, comprising 3203 patients(n = 2027 LS and 1176 HS). Primary outcome analysis revealed a significant decrease in anastomotic leakage(RR = 0.51, 95%CI: 0.41-0.65; P < 0.00001) a s s o c i a t e d w i t h L S a n a s t o m o s i s. A s i g n i f i c a n t l y reduced rate of anastomotic stricture associated with LS was also found(RR = 0.56, 95%CI: 0.49-0.64; P < 0.00001). A subgroup analysis according to the site of anastomosis revealed a significantly reduced rate of anastomotic stricture(P < 0.00001). Although there was no significant difference in the decrease in thoracic anastomotic leakage, there was a significant decrease in cervical anastomotic leakage associated with LS(P < 0.00001).CONCLUSION: This meta-analysis indicates that the LS technique contributes to a reduced rate of leakage and stricture compared with the HS method.展开更多
A compact linearly polarized, low-noise, narrow-linewidth, single-frequency fiber laser at 1950nm is demonstrated. This compact fiber laser is based on a 21-mm-long homemade Tm3＋-doped germanate glass fiber. Over 100...A compact linearly polarized, low-noise, narrow-linewidth, single-frequency fiber laser at 1950nm is demonstrated. This compact fiber laser is based on a 21-mm-long homemade Tm3＋-doped germanate glass fiber. Over 100-mW stable continuous-wave single transverse and longitudinal mode lasing at 195Ohm are achieved. The measured relative intensity noise is less than -135dB/Hz at frequencies over 5 MHz. The signal-to-noise ratio of the laser is larger than 72dB, and the laser linewidth is less than 6kHz, while the obtained linear polarization extinction ratio is higher than 22 dB.展开更多
The bending problem of a functionally graded anisotropic cantilever beam subjected to a linearly distributed load is investigated. The analysis is based on the exact elasticity equations for the plane stress problem. ...The bending problem of a functionally graded anisotropic cantilever beam subjected to a linearly distributed load is investigated. The analysis is based on the exact elasticity equations for the plane stress problem. The stress function is introduced and assumed in the form of a polynomial of the longitudinal coordinate. The expressions for stress components are then educed from the stress function by simple differentiation. The stress function is determined from the compatibility equation as well as the boundary conditions by a skilful deduction. The analytical solution is compared with FEM calculation, indicating a good agreement.展开更多
This paper describes the successful fabrication of 4H-SiC junction barrier Schottky （JBS） rectifiers with a linearly graded field limiting ring （LG-FLR）. Linearly variable ring spacings for the FLR termination are...This paper describes the successful fabrication of 4H-SiC junction barrier Schottky （JBS） rectifiers with a linearly graded field limiting ring （LG-FLR）. Linearly variable ring spacings for the FLR termination are applied to improve the blocking voltage by reducing the peak surface electric field at the edge termination region, which acts like a variable lateral doping profile resulting in a gradual field distribution. The experimental results demonstrate a breakdown voltage of 5 kV at the reverse leakage current density of 2 mA/cm2 （about 80% of the theoretical value）. Detailed numerical simulations show that the proposed termination structure provides a uniform electric field profile compared to the conventional FLR termi- nation, which is responsible for 45% improvement in the reverse blocking voltage despite a 3.7% longer total termination length.展开更多
A class of new fuzzy inference systems New-FISs is presented.Compared with the standard fuzzy system, New-FIS is still a universal approximator and has no fuzzy rule base and linearly parameter growth. Thus, it effect...A class of new fuzzy inference systems New-FISs is presented.Compared with the standard fuzzy system, New-FIS is still a universal approximator and has no fuzzy rule base and linearly parameter growth. Thus, it effectively overcomes the second "curse of dimensionality":there is an exponential growth in the number of parameters of a fuzzy system as the number of input variables,resulting in surprisingly reduced computational complexity and being especially suitable for applications,where the complexity is of the first importance with respect to the approximation accuracy.展开更多
In this study, we demonstrate an all-fiber high-power linearly-polarized tunable Raman fiber laser system. An in- house high-power tunable fiber laser was employed as the pump source. A fiber loop mirror （FLM） servi...In this study, we demonstrate an all-fiber high-power linearly-polarized tunable Raman fiber laser system. An in- house high-power tunable fiber laser was employed as the pump source. A fiber loop mirror （FLM） serving as a high reflectivity mirror and a flat-cut endface serving as an output coupler were adopted to provide broadband feedback. A piece of 59-m commercial passive fiber was used as the Raman gain medium. The Raman laser had a 27.6 nm tuning range from 1112 nm to 1139.6 nm and a maximum output power of 125.3 W, which corresponds to a conversion efficiency of 79.4%. The polarization extinction ratio （PER） at all operational wavelengths was measured to be over 21 dB. To the best of our knowledge, this is the first report on a hundred-watt level linearly-polarized tunable Raman fiber laser.展开更多
In this paper,we demonstrate an all-fiber linearly polarized fiber laser oscillator.The single polarization of the oscillator is achieved through the careful designing of the active fiber coiling.The relationship betw...In this paper,we demonstrate an all-fiber linearly polarized fiber laser oscillator.The single polarization of the oscillator is achieved through the careful designing of the active fiber coiling.The relationship between fiber coiling diameter and polarization extinction ratio and optical efficiency is studied,whose results lead to an optimized system.The thermal management of the oscillator is also refined,which allows the oscillator to reach a maximum output power of44.1 W with an optical-to-optical efficiency of 57.9%.A high average polarization extinction ratio of 21.6 d B is achieved during a 2-hour stability test.The oscillator also owns a narrow 3-d B bandwidth of 0.1 nm,as well as near-diffraction-limit beam quality of M^2～ 1.14.展开更多
In this paper, a primal-dual path-following interior-point algorithm for linearly constrained convex optimization(LCCO) is presented.The algorithm is based on a new technique for finding a class of search directions a...In this paper, a primal-dual path-following interior-point algorithm for linearly constrained convex optimization(LCCO) is presented.The algorithm is based on a new technique for finding a class of search directions and the strategy of the central path.At each iteration, only full-Newton steps are used.Finally, the favorable polynomial complexity bound for the algorithm with the small-update method is deserved, namely, O(√n log n /ε).展开更多
Just like an electronic diode that allows the electrical current to flow in one direction only, a kind of chiral metamaterial structure with a similar functionality for the electromagnetic wave is proposed. The design...Just like an electronic diode that allows the electrical current to flow in one direction only, a kind of chiral metamaterial structure with a similar functionality for the electromagnetic wave is proposed. The designed nanostructure that consists of twisted metallic split-ring resonators on both sides of a dielectric substrate achieves asymmetric transmission for a forward and backward propagating linearly polarized wave by numerical simulation in near-infrared band. Difference in transmission efficiency of the optimized structure between the same polarized waves incident from opposite directions can reach a maximum at the communication wavelength （1.55 μm）. Moreover, the simulation results of this structure also exhibit strong optical activity and circular dichroism.展开更多
In this paper, we propose and analyze an accelerated augmented Lagrangian method（denoted by AALM） for solving the linearly constrained convex programming. We show that the convergence rate of AALM is O（1/k^2） whil...In this paper, we propose and analyze an accelerated augmented Lagrangian method（denoted by AALM） for solving the linearly constrained convex programming. We show that the convergence rate of AALM is O（1/k^2） while the convergence rate of the classical augmented Lagrangian method（ALM） is O1 k. Numerical experiments on the linearly constrained 1-2minimization problem are presented to demonstrate the effectiveness of AALM.展开更多
The plane structure of bars jointed to a rigid-body is a complex and universal structure.Some other structure of bars can be considered as its special cases. Many material have different stress-strain relation in tens...The plane structure of bars jointed to a rigid-body is a complex and universal structure.Some other structure of bars can be considered as its special cases. Many material have different stress-strain relation in tension and compression, generally the relation is nonlinear. In this paper,we use the constitutive model of linearly elastic and power hardening of strength difference to analyze plane structure of bars. The displacement method is used to derive the universal expression of calculating stress and strain. The nonlinear equations for computing displacements of the rigid-body has been given and general computing program has been worked out. This problem has been solved satisfactorily.展开更多
Active set method and gradient projection method are curre nt ly the main approaches for linearly constrained convex programming. Interior-po int method is one of the most effective choices for linear programming. In ...Active set method and gradient projection method are curre nt ly the main approaches for linearly constrained convex programming. Interior-po int method is one of the most effective choices for linear programming. In the p aper a predictor-corrector interior-point algorithm for linearly constrained c onvex programming under the predictor-corrector motivation was proposed. In eac h iteration, the algorithm first performs a predictor-step to reduce the dualit y gap and then a corrector-step to keep the points close to the central traject ory. Computations in the algorithm only require that the initial iterate be nonn egative while feasibility or strict feasibility is not required. It is proved th at the algorithm is equivalent to a level-1 perturbed composite Newton method. Numerical experiments on twenty-six standard test problems are made. The result s show that the proposed algorithm is stable and robust.展开更多
We propose a scheme to coherently control the field-free orientation of NO molecule whose rotational temperature is above 0 K. It is found that the maximum molecular orientation is affected by two factors： one is the...We propose a scheme to coherently control the field-free orientation of NO molecule whose rotational temperature is above 0 K. It is found that the maximum molecular orientation is affected by two factors： one is the sum of the population of M = 0 rotational states and the other is their distribution, however, their distribution plays a much more significant role in molecular orientation than the sum of their population. By adopting a series of linearly polarized pulses resonant with the rotational states, the distribution of M = 0 rotational states is well rearranged. Though the number of pulses used is small, a relatively high orientation degree can be obtained. This scheme provides a promising approach to the achievement of a good orientation effect.展开更多
A linearly polarized operation Ho： YAG laser at 2090.5 nm with a corner cube cavity is demonstrated. A polarizer with high reflectivity for the s-polarized light at the laser wavelength is employed to achieve a linea...A linearly polarized operation Ho： YAG laser at 2090.5 nm with a corner cube cavity is demonstrated. A polarizer with high reflectivity for the s-polarized light at the laser wavelength is employed to achieve a linearly polarized laser. In the same case of resonator length, the corner cube can be used to cut the volume of the Ho：YAG laser and to enhance the stability of the system. The maximum linearly polarized output power of 5.8 W is achieved at the absorbed pump power of 23.3 W, corresponding to a slope efficiency of 29.7%, and the optical-optical conversion efficiency is around 24.9%. The M2 factors of the 2.09μm laser are 2.4 and 1.2 along the horizontal and vertical directions, respectively.展开更多
We investigate the ellipticity of the high-order harmonic generation from the oriented H_(2)^(+)exposed to a linearly polarized laser field by numerically solving the two-dimensional time-dependent Schrodinger equatio...We investigate the ellipticity of the high-order harmonic generation from the oriented H_(2)^(+)exposed to a linearly polarized laser field by numerically solving the two-dimensional time-dependent Schrodinger equation(2 D TDSE).Numerical simulations show that the harmonic ellipticity is remarkably sensitive to the alignment angle.The harmonic spectrum is highly elliptically polarized at a specific alignment angleθ=30°,which is insensitive to the variation of the laser parameters.The position of the harmonic intensity minima indicates the high ellipticity,which can be attributed to the two-center interference effect.The high ellipticity can be explained by the phase difference of the harmonics.This result facilitates the synthesis of a highly elliptical isolated attosecond pulse with duration down to 65 as,which can be served as a powerful tool to explore the ultrafast dynamics of molecules and study chiral light-matter interaction.展开更多
文摘The purpose of the current article is to study the H^(1)-stability for all positive time of the linearly extrapolated BDF2 timestepping scheme for the magnetohydrodynamics and Boussinesq equations.Specifically,we discretize in time using the linearly backward differentiation formula,and by employing both the discrete Gronwall lemma and the discrete uniform Gronwall lemma,we establish that each numerical scheme is uniformly bounded in the H^(1)-norm.
文摘As the thickness of an SOI layer varies,a minimum breakdown voltage is reached when the thickness is about 2μm. The vertical electric field of the SOI LDMOS with a drift region which is vertically linearly graded is constant. The vertically linearly graded concentration drift can be achieved by impurity implanting followed by thermal diffusion. In this way,the vertical breakdown voltage of SOI LDMOS with 2μm thickness SOI layer can be improved by 43%. The on-state resistance is lowered by 24 % because of the higher impurity concentration of the SOI surface.
文摘A novel 2D analytical model for the doping profile of the bulk silicon RESURF LDMOS drift region is proposed. According to the proposed model, to obtain good performance, the doping profile in the total drift region of a RESURF LDMOS with a field plate should be piecewise linearly graded. The breakdown voltage of the proposed RESURF LDMOS with a piecewise linearly graded doping drift region is improved by 58. 8%, and the specific on-resistance is reduced by 87. 4% compared with conventional LDMOS. These results are verified by the two-dimensional process simulator Tsuprem-4 and the device simulator Medici.
基金The NSF (10871042,10971024) of Chinathe Specialized Research Fund (200802860024) for the Doctoral Program of Higher Education
文摘A ring R is called linearly McCoy if whenever linear polynomials f（x）, g（x） e R[x]／{0） satisfy f（x）g（x） ： O, then there exist nonzero elements r, s ∈ R such that f（x）r ： sg（x） =0. For a ring endomorphism α, we introduced the notion of α-skew linearly McCoy rings by considering the polynomials in the skew polynomial ring R[x; α] in place of the ring R[x]. A number of properties of this generalization are established and extension properties of α-skew linearly McCoy rings are given.
文摘This report describes an equivalent doping profile transformation method with which the avalanche breakdown voltage of the asymmetric linearly graded junction was analytically predicted.The maximum breakdown voltage and the different depletion layer extension on the diffused side and substrate side are demonstrated in the report.The report shows the equivalent doping profile method is valid to predict the breakdown voltage of the complex P N junction.The analytical results agree with the experimental breakdown voltage in comparison with the abrupt junction and symmetric linearly graded junction approximations.
文摘AIM: To compare the outcomes of hand-sewn(HS) and linearly stapled(LS) esophagogastric anastomosis for esophageal cancer.METHODS: Before beginning this study, a rigorous protocol was established according to the recommendations of the Cochrane Collaboration. Databases and references were searched for all randomizedcontrolled trials and comparative clinical studies that compared LS with HS esophagogastric anastomosis for esophageal cancer. The primary outcomes compared were anastomotic leak and stricture. Subgroup analyses were performed according to site of anastomosis.RESULTS: Fifteen studies were used, comprising 3203 patients(n = 2027 LS and 1176 HS). Primary outcome analysis revealed a significant decrease in anastomotic leakage(RR = 0.51, 95%CI: 0.41-0.65; P < 0.00001) a s s o c i a t e d w i t h L S a n a s t o m o s i s. A s i g n i f i c a n t l y reduced rate of anastomotic stricture associated with LS was also found(RR = 0.56, 95%CI: 0.49-0.64; P < 0.00001). A subgroup analysis according to the site of anastomosis revealed a significantly reduced rate of anastomotic stricture(P < 0.00001). Although there was no significant difference in the decrease in thoracic anastomotic leakage, there was a significant decrease in cervical anastomotic leakage associated with LS(P < 0.00001).CONCLUSION: This meta-analysis indicates that the LS technique contributes to a reduced rate of leakage and stricture compared with the HS method.
基金Supported by the National High-Technology Research and Development Program of China under Grant Nos 2013AA031502 and 2014AA041902the National Natural Science Foundation of China under Grant Nos 11174085,51132004,and 51302086+3 种基金the Natural Science Foundation of Guangdong Province under Grant Nos S2011030001349 and S20120011380the China National Funds for Distinguished Young Scientists under Grant No 61325024the Science and Technology Project of Guangdong Province under Grant No 2013B090500028the ’Cross and Cooperative’ Science and Technology Innovation Team Project of Chinese Academy of Sciences under Grant No 2012-119
文摘A compact linearly polarized, low-noise, narrow-linewidth, single-frequency fiber laser at 1950nm is demonstrated. This compact fiber laser is based on a 21-mm-long homemade Tm3＋-doped germanate glass fiber. Over 100-mW stable continuous-wave single transverse and longitudinal mode lasing at 195Ohm are achieved. The measured relative intensity noise is less than -135dB/Hz at frequencies over 5 MHz. The signal-to-noise ratio of the laser is larger than 72dB, and the laser linewidth is less than 6kHz, while the obtained linear polarization extinction ratio is higher than 22 dB.
基金Project supported by the National Natural Science Foundation of China(Nos.10472102 and 10432030)
文摘The bending problem of a functionally graded anisotropic cantilever beam subjected to a linearly distributed load is investigated. The analysis is based on the exact elasticity equations for the plane stress problem. The stress function is introduced and assumed in the form of a polynomial of the longitudinal coordinate. The expressions for stress components are then educed from the stress function by simple differentiation. The stress function is determined from the compatibility equation as well as the boundary conditions by a skilful deduction. The analytical solution is compared with FEM calculation, indicating a good agreement.
基金Project supported by the State Key Program of the National Natural Science Foundation of China(Grant No.61234006)
文摘This paper describes the successful fabrication of 4H-SiC junction barrier Schottky （JBS） rectifiers with a linearly graded field limiting ring （LG-FLR）. Linearly variable ring spacings for the FLR termination are applied to improve the blocking voltage by reducing the peak surface electric field at the edge termination region, which acts like a variable lateral doping profile resulting in a gradual field distribution. The experimental results demonstrate a breakdown voltage of 5 kV at the reverse leakage current density of 2 mA/cm2 （about 80% of the theoretical value）. Detailed numerical simulations show that the proposed termination structure provides a uniform electric field profile compared to the conventional FLR termi- nation, which is responsible for 45% improvement in the reverse blocking voltage despite a 3.7% longer total termination length.
基金This work was supported by the RGC Competitive Earmarked Research Grant (No. PolyU 5065/98E)Natural Science Foundation of China (No. 60225015)+1 种基金Natural Science Foundation of Jiangsu Province (No. BK2003017)National Key Labruary of Novel Software Tech
文摘A class of new fuzzy inference systems New-FISs is presented.Compared with the standard fuzzy system, New-FIS is still a universal approximator and has no fuzzy rule base and linearly parameter growth. Thus, it effectively overcomes the second "curse of dimensionality":there is an exponential growth in the number of parameters of a fuzzy system as the number of input variables,resulting in surprisingly reduced computational complexity and being especially suitable for applications,where the complexity is of the first importance with respect to the approximation accuracy.
基金Project supported by the Fok Ying-Tong Education Foundation,China(Grant No.151062)
文摘In this study, we demonstrate an all-fiber high-power linearly-polarized tunable Raman fiber laser system. An in- house high-power tunable fiber laser was employed as the pump source. A fiber loop mirror （FLM） serving as a high reflectivity mirror and a flat-cut endface serving as an output coupler were adopted to provide broadband feedback. A piece of 59-m commercial passive fiber was used as the Raman gain medium. The Raman laser had a 27.6 nm tuning range from 1112 nm to 1139.6 nm and a maximum output power of 125.3 W, which corresponds to a conversion efficiency of 79.4%. The polarization extinction ratio （PER） at all operational wavelengths was measured to be over 21 dB. To the best of our knowledge, this is the first report on a hundred-watt level linearly-polarized tunable Raman fiber laser.
基金Project supported by the National Key Research and Development Program of China(Grant No.2017YFB1104500)the National Natural Science Foundation of China(Grant No.61675114)the Tsinghua University(THU)Initiative Scientific Research Program,China(Grant No.20151080709)
文摘In this paper,we demonstrate an all-fiber linearly polarized fiber laser oscillator.The single polarization of the oscillator is achieved through the careful designing of the active fiber coiling.The relationship between fiber coiling diameter and polarization extinction ratio and optical efficiency is studied,whose results lead to an optimized system.The thermal management of the oscillator is also refined,which allows the oscillator to reach a maximum output power of44.1 W with an optical-to-optical efficiency of 57.9%.A high average polarization extinction ratio of 21.6 d B is achieved during a 2-hour stability test.The oscillator also owns a narrow 3-d B bandwidth of 0.1 nm,as well as near-diffraction-limit beam quality of M^2～ 1.14.
基金supported by the Shanghai Pujiang Program (Grant No.06PJ14039)the Science Foundation of Shanghai Municipal Commission of Education (Grant No.06NS031)
文摘In this paper, a primal-dual path-following interior-point algorithm for linearly constrained convex optimization(LCCO) is presented.The algorithm is based on a new technique for finding a class of search directions and the strategy of the central path.At each iteration, only full-Newton steps are used.Finally, the favorable polynomial complexity bound for the algorithm with the small-update method is deserved, namely, O(√n log n /ε).
基金Project supported by the National Natural Science Foundation of China(Grant No.61078060)the Fund from the Ningbo Optoelectronic Materials and Devices Creative Team,China(Grant No.2009B21007)partially sponsored by K.C.Wong Magna Fund in Ningbo University
文摘Just like an electronic diode that allows the electrical current to flow in one direction only, a kind of chiral metamaterial structure with a similar functionality for the electromagnetic wave is proposed. The designed nanostructure that consists of twisted metallic split-ring resonators on both sides of a dielectric substrate achieves asymmetric transmission for a forward and backward propagating linearly polarized wave by numerical simulation in near-infrared band. Difference in transmission efficiency of the optimized structure between the same polarized waves incident from opposite directions can reach a maximum at the communication wavelength （1.55 μm）. Moreover, the simulation results of this structure also exhibit strong optical activity and circular dichroism.
基金Supported by Fujian Natural Science Foundation(2016J01005)Strategic Priority Research Program of the Chinese Academy of Sciences(XDB18010202)
文摘In this paper, we propose and analyze an accelerated augmented Lagrangian method（denoted by AALM） for solving the linearly constrained convex programming. We show that the convergence rate of AALM is O（1/k^2） while the convergence rate of the classical augmented Lagrangian method（ALM） is O1 k. Numerical experiments on the linearly constrained 1-2minimization problem are presented to demonstrate the effectiveness of AALM.
文摘The plane structure of bars jointed to a rigid-body is a complex and universal structure.Some other structure of bars can be considered as its special cases. Many material have different stress-strain relation in tension and compression, generally the relation is nonlinear. In this paper,we use the constitutive model of linearly elastic and power hardening of strength difference to analyze plane structure of bars. The displacement method is used to derive the universal expression of calculating stress and strain. The nonlinear equations for computing displacements of the rigid-body has been given and general computing program has been worked out. This problem has been solved satisfactorily.
文摘Active set method and gradient projection method are curre nt ly the main approaches for linearly constrained convex programming. Interior-po int method is one of the most effective choices for linear programming. In the p aper a predictor-corrector interior-point algorithm for linearly constrained c onvex programming under the predictor-corrector motivation was proposed. In eac h iteration, the algorithm first performs a predictor-step to reduce the dualit y gap and then a corrector-step to keep the points close to the central traject ory. Computations in the algorithm only require that the initial iterate be nonn egative while feasibility or strict feasibility is not required. It is proved th at the algorithm is equivalent to a level-1 perturbed composite Newton method. Numerical experiments on twenty-six standard test problems are made. The result s show that the proposed algorithm is stable and robust.
基金Project supported by the National Basic Research Program of China(Grant No.2013CB922200)the National Natural Science Foundation of China(Grant Nos.11034003,11474129,11274141,and 11304116)+1 种基金the Research Fund for the Doctoral Program of Higher Education of China(Grant No.20130061110021)the Graduate Innovation Fund of Jilin University(Grant No.2015091)
文摘We propose a scheme to coherently control the field-free orientation of NO molecule whose rotational temperature is above 0 K. It is found that the maximum molecular orientation is affected by two factors： one is the sum of the population of M = 0 rotational states and the other is their distribution, however, their distribution plays a much more significant role in molecular orientation than the sum of their population. By adopting a series of linearly polarized pulses resonant with the rotational states, the distribution of M = 0 rotational states is well rearranged. Though the number of pulses used is small, a relatively high orientation degree can be obtained. This scheme provides a promising approach to the achievement of a good orientation effect.
基金Supported by the National Natural Science Foundation of China under Grant Nos 61308009 and 61405047the China Postdoctoral Science Foundation Funded Project under Grant No 2013M540288+1 种基金the Fundamental Research Funds for the Central Universities under Grant Nos HIT.NSRIF.2014044 and HIT.NSRIF.2015042the Science Fund for Outstanding Youths of Heilongjiang Province under Grant No JQ201310
文摘A linearly polarized operation Ho： YAG laser at 2090.5 nm with a corner cube cavity is demonstrated. A polarizer with high reflectivity for the s-polarized light at the laser wavelength is employed to achieve a linearly polarized laser. In the same case of resonator length, the corner cube can be used to cut the volume of the Ho：YAG laser and to enhance the stability of the system. The maximum linearly polarized output power of 5.8 W is achieved at the absorbed pump power of 23.3 W, corresponding to a slope efficiency of 29.7%, and the optical-optical conversion efficiency is around 24.9%. The M2 factors of the 2.09μm laser are 2.4 and 1.2 along the horizontal and vertical directions, respectively.
基金supported by the National Natural Science Foundation of China(Grants Nos.12074142 and 11904122)。
文摘We investigate the ellipticity of the high-order harmonic generation from the oriented H_(2)^(+)exposed to a linearly polarized laser field by numerically solving the two-dimensional time-dependent Schrodinger equation(2 D TDSE).Numerical simulations show that the harmonic ellipticity is remarkably sensitive to the alignment angle.The harmonic spectrum is highly elliptically polarized at a specific alignment angleθ=30°,which is insensitive to the variation of the laser parameters.The position of the harmonic intensity minima indicates the high ellipticity,which can be attributed to the two-center interference effect.The high ellipticity can be explained by the phase difference of the harmonics.This result facilitates the synthesis of a highly elliptical isolated attosecond pulse with duration down to 65 as,which can be served as a powerful tool to explore the ultrafast dynamics of molecules and study chiral light-matter interaction.
