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131.
132.
Kolafa J 《Journal of computational chemistry》2004,25(3):335-342
An improved method for classic molecular dynamics of polarizable molecules is proposed. The method uses a predictor, one evaluation of the electrostatic field per integration step, and relaxation (damping). The self-consistent solution is approximated with error of the second order (with respect to the timestep). The time reversibility (long-time energy conservation) error is of the (2n - 1)th order, where n is the predictor length. The method is easy to implement, efficient, accurate, and suitable for any model of polarizability. 相似文献
133.
电子喉语音存在基频单一、发声机械、辐射噪声大等多种缺陷,这严重影响了电子喉语音可懂度和自然度,特别是对汉语普通话之类的声调语言,问题尤其严重.汉语普通话电子喉语音识别存在辅音混淆的问题并且识别结果没有声调,因此本文在识别结果的基础之上设计了拼音拼写修正器和声调标注工具,再结合基于Tacotron-2的TTS实现了电子喉语音向正常语音的转换.客观评价实验结果表明,拼音拼写修正器可以提高拼音准确率,声调标注在有上下文的语义环境中具有较高准确率.主观听力测试结果表明,本文所提方法在不同语言水平上提高了汉语普通话电子喉语音的可懂度和自然度.研究结果表明,本文设计的方法可以将不带声调的电子喉语音转换为正常语音,相比于传统语音转换方法具有更高的性能. 相似文献
134.
135.
In this paper, we introduce some pressure segregation methods obtained from a non‐standard version of the discrete monolithic system, where the continuity equation has been replaced by a pressure Poisson equation obtained at the discrete level. In these methods it is the velocity instead of the pressure the extrapolated unknown. Moreover, predictor–corrector schemes are suggested, again motivated by the new monolithic system. Key implementation aspects are discussed, and a complete stability analysis is performed. We end with a set of numerical examples in order to compare these methods with classical pressure‐correction schemes. Copyright © 2007 John Wiley & Sons, Ltd. 相似文献
136.
A.G. Bratsos 《Numerical Methods for Partial Differential Equations》2008,24(3):833-844
A numerical method based on a predictor–corrector (P‐C) scheme arising from the use of rational approximants of order 3 to the matrix‐exponential term in a three‐time level recurrence relation is applied successfully to the one‐dimensional sine‐Gordon equation, already known from the bibliography. In this P‐C scheme a modification in the corrector (MPC) has been proposed according to which the already evaluated corrected values are considered. The method, which uses as predictor an explicit finite‐difference scheme arising from the second order rational approximant and as corrector an implicit one, has been tested numerically on the single and the soliton doublets. Both the predictor and the corrector schemes are analyzed for local truncation error and stability. From the investigation of the numerical results and the comparison of them with other ones known from the bibliography it has been derived that the proposed P‐C/MPC schemes at least coincide in terms of accuracy with them. © 2007 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq, 2008 相似文献
137.
Youcef Amirat Olivier Bodart Umberto De Maio Antonio Gaudiello 《Annali dell'Universita di Ferrara》2007,53(2):135-148
We consider a viscous incompressible flow in an infinite horizontal domain bounded at the bottom by a smooth wall and at the
top by a rough wall. The latter is assumed to consist in a plane wall covered with periodically distributed asperities which
size depends on a small parameter, and with a fixed height. We assume that the flow is governed by the stationary Stokes equations.
Using a boundary layer corrector we derive and analyze a first order asymptotic approximation of the flow.
相似文献
138.
This paper presents a parallel implementation of fractional solvers for the incompressible Navier–Stokes equations using an algebraic approach. Under this framework, predictor–corrector and incremental projection schemes are seen as sub-classes of the same class, making apparent its differences and similarities. An additional advantage of this approach is to set a common basis for a parallelization strategy, which can be extended to other split techniques or to compressible flows. 相似文献
139.
A conformal optical system refers to the one whose first optical surface conforms to both aerodynamic and imaging requirements. Appropriate correction is required because a conformal dome induces significant aberrations. This paper intends to explain that an effective solution to the easy-fabrication conic surface corrector compensates aberrations induced by a coaxial aspheric dome. A conformal optical system with an ellipsoid MgF2 conformal dome, which has a fineness ratio of 2.0, is designed as an example. The field of regard angle is pm 30 degrees with a pm 2 degree instantaneous field of view. The system's ultimate value of modulation transfer function is close to the diffraction limit, which indicates that the performance of the conic conformal optical system with a fixed conic corrector meets the imaging requirements. 相似文献
140.
叙述无光焦度补偿组与次镜重合时的全球面双反射系统的设计,给出利用PW法求解初始结构的基本理论,阐述应用无光焦度补偿组来平衡球面反射系统像差的方法。通过改变遮拦比K和焦点伸出量进行光线追迹,选择出该类系统K和的最佳组合。给出设计实例:系统工作波段=450 nm~700 nm、焦距f=1 600 mm、相对孔径A=1/8、视场角=05,遮拦比K=0.35、焦点伸出量=0.1,系统优化后的球差系数 SⅠ=-0.001 207,彗差系数SⅡ=0.000 192,波像差W=0.043 27。 相似文献