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梯度凝固法晶体生长应用磁场的研究进展
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作者 赵兴凯 韦华 +3 位作者 叶晓达 王顺金 韩家贤 柳廷龙 《云南化工》 CAS 2023年第4期15-20,共6页
在梯度凝固法晶体生长中应用磁场可以有效提高溶质分布的均匀性,改善生长界面的形貌。主要综述了在VGF法或VB法晶体生长中应用磁场的研究进展,包括行波磁场、旋转磁场和交变磁场的产生原理,以及三种磁场在熔体中形成的对流模式和对晶体... 在梯度凝固法晶体生长中应用磁场可以有效提高溶质分布的均匀性,改善生长界面的形貌。主要综述了在VGF法或VB法晶体生长中应用磁场的研究进展,包括行波磁场、旋转磁场和交变磁场的产生原理,以及三种磁场在熔体中形成的对流模式和对晶体生长的影响。提出了三种磁场各自的优势和在实际晶体生产上的应用前景。 展开更多
关键词 磁场垂直温度梯度 垂直布里奇曼 晶体生长 熔体对流 生长界面形貌 溶质分布
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VGF法生长InP单晶循环水的影响分析 被引量:1
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作者 叶晓达 赵兴凯 +6 位作者 韩家贤 韦华 王顺金 邱锋 柳廷龙 刘汉保 黄平 《云南化工》 CAS 2022年第10期24-28,共5页
磷化铟与砷化镓同为Ⅲ-Ⅴ族化合物半导体材料,广泛应用于光通信、微波毫米波通信等领域。由于垂直温度梯度凝固(VGF)技术中,晶体受到的温度梯度小,能生长出低位错,甚至零位错的单晶,而被广泛应用于磷化铟单晶的制备中。影响磷化铟单晶... 磷化铟与砷化镓同为Ⅲ-Ⅴ族化合物半导体材料,广泛应用于光通信、微波毫米波通信等领域。由于垂直温度梯度凝固(VGF)技术中,晶体受到的温度梯度小,能生长出低位错,甚至零位错的单晶,而被广泛应用于磷化铟单晶的制备中。影响磷化铟单晶生长的因素很多,其中最重要的是热场环境,而冷却循环水能够起到调节热场梯度的作用,有较大的研究意义。通过控制单晶炉循环水进水温度及进水流量,探究了进水温度22~34℃与进水流量60~300 L/h的不同组合条件下,InP单晶生长的不同结果,并对不同进水温度和水流量对单晶生长的影响规律进行了分析。结果表明,循环水的温度和流量对热场温度梯度有影响,在进水温度30℃,流量100 L/h时,磷化铟的单晶率有所提升,位错密度在50/cm^(2)以下。 展开更多
关键词 垂直温度梯度凝固技术 INP单晶 循环水 水流量 温度
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Algebraic dynamics algorithm:Numerical comparison with Runge-Kutta algorithm and symplectic geometric algorithm 被引量:7
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作者 wang shunjin ZHANG Hua 《Science China(Physics,Mechanics & Astronomy)》 SCIE EI CAS 2007年第1期53-69,共17页
Based on the exact analytical solution of ordinary differential equations, a truncation of the Taylor series of the exact solution to the Nth order leads to the Nth order algebraic dynamics algorithm. A detailed numer... Based on the exact analytical solution of ordinary differential equations, a truncation of the Taylor series of the exact solution to the Nth order leads to the Nth order algebraic dynamics algorithm. A detailed numerical comparison is presented with Runge-Kutta algorithm and symplectic geometric algorithm for 12 test models. The results show that the algebraic dynamics algorithm can better preserve both geometrical and dynamical fidelity of a dynamical system at a controllable precision, and it can solve the problem of algorithm-induced dissipation for the Runge-Kutta algorithm and the problem of algorithm-induced phase shift for the symplectic geometric algorithm. 展开更多
关键词 algebraic dynamics ALGORITHM for ordinary differential equations preserving both geometrical and dynamical FIDELITY NUMERICAL COMPARISON with RUNGE-KUTTA ALGORITHM and SYMPLECTIC geometric ALGORITHM
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Algebraic dynamics solutions and algebraic dynamics algorithm for nonlinear partial differential evolution equations of dynamical systems 被引量:3
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作者 wang shunjin ZHANG Hua 《Science China(Physics,Mechanics & Astronomy)》 SCIE EI CAS 2008年第6期577-590,共14页
Using functional derivative technique in quantum field theory, the algebraic dy-namics approach for solution of ordinary differential evolution equations was gen-eralized to treat partial differential evolution equati... Using functional derivative technique in quantum field theory, the algebraic dy-namics approach for solution of ordinary differential evolution equations was gen-eralized to treat partial differential evolution equations. The partial differential evo-lution equations were lifted to the corresponding functional partial differential equations in functional space by introducing the time translation operator. The functional partial differential evolution equations were solved by algebraic dynam-ics. The algebraic dynamics solutions are analytical in Taylor series in terms of both initial functions and time. Based on the exact analytical solutions, a new nu-merical algorithm—algebraic dynamics algorithm was proposed for partial differ-ential evolution equations. The difficulty of and the way out for the algorithm were discussed. The application of the approach to and computer numerical experi-ments on the nonlinear Burgers equation and meteorological advection equation indicate that the algebraic dynamics approach and algebraic dynamics algorithm are effective to the solution of nonlinear partial differential evolution equations both analytically and numerically. 展开更多
关键词 functional PARTIAL DIFFERENTIAL EQUATIONS exact ALGEBRAIC DYNAMICS SOLUTIONS of nonlinear PARTIAL DIFFERENTIAL evolution EQUATIONS ALGEBRAIC DYNAMICS algorithm
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Symplectic algebraic dynamics algorithm 被引量:2
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作者 wang shunjin ZHANG Hua 《Science China(Physics,Mechanics & Astronomy)》 SCIE EI CAS 2007年第2期133-143,共11页
Based on the algebraic dynamics solution of ordinary differential equations and integration of $\hat L$ , the symplectic algebraic dynamics algorithm s? n is designed, which preserves the local symplectic geometric st... Based on the algebraic dynamics solution of ordinary differential equations and integration of $\hat L$ , the symplectic algebraic dynamics algorithm s? n is designed, which preserves the local symplectic geometric structure of a Hamiltonian system and possesses the same precision of the na?ve algebraic dynamics algorithm ? n . Computer experiments for the 4th order algorithms are made for five test models and the numerical results are compared with the conventional symplectic geometric algorithm, indicating that s? n has higher precision, the algorithm-induced phase shift of the conventional symplectic geometric algorithm can be reduced, and the dynamical fidelity can be improved by one order of magnitude. 展开更多
关键词 SYMPLECTIC ALGEBRAIC dynamics ALGORITHM PRESERVING local SYMPLECTIC geometric structure reduction of algo-rithm-induced phase shift improving DYNAMICAL FIDELITY
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Algebraic dynamics solution to and algebraic dynamics algorithm for nonlinear advection equation 被引量:2
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作者 ZHANG Hua LU WeiTao wang shunjin 《Science China(Physics,Mechanics & Astronomy)》 SCIE EI CAS 2008年第10期1470-1478,共9页
Algebraic dynamics approach and algebraic dynamics algorithm for the solution of nonlinear partial differential equations are applied to the nonlinear advection equa-tion. The results show that the approach is effecti... Algebraic dynamics approach and algebraic dynamics algorithm for the solution of nonlinear partial differential equations are applied to the nonlinear advection equa-tion. The results show that the approach is effective for the exact analytical solu-tion and the algorithm has higher precision than other existing algorithms in nu-merical computation for the nonlinear advection equation. 展开更多
关键词 NONLINEAR advection EQUATION ALGEBRAIC DYNAMICS SOLUTION in FUNCTIONAL space ALGEBRAIC DYNAMICS algo-rithm for NONLINEAR advection EQUATION
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Algebraic dynamics solution and algebraic dynamics algorithm of Burgers equations 被引量:2
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作者 ZHANG Hua LU WeiTao wang shunjin 《Science China(Physics,Mechanics & Astronomy)》 SCIE EI CAS 2008年第11期1647-1652,共6页
Algebraic dynamics solution and algebraic dynamics algorithm of nonlinear partial differential evolution equations in the functional space are applied to Burgers equation. The results indicate that the approach is eff... Algebraic dynamics solution and algebraic dynamics algorithm of nonlinear partial differential evolution equations in the functional space are applied to Burgers equation. The results indicate that the approach is effective for analytical solutions to Burgers equation, and the algorithm for numerical solutions of Burgers equation is more stable, with higher precision than other existing finite difference algo-rithms. 展开更多
关键词 ALGEBRAIC DYNAMICS SOLUTION in functional space ALGEBRAIC DYNAMICS ALGORITHM for BURGERS equation
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