分析了二维渗流场与二维温度场之间的相似性,基于许多实际工程中的渗流问题都可视为平面应变情况,提出利用M at lab软件的热分析功能进行非饱和土渗流的计算方法,阐述M at lab软件中的PDE(偏微分方程)工具箱在求解计算流体力学问题中的...分析了二维渗流场与二维温度场之间的相似性,基于许多实际工程中的渗流问题都可视为平面应变情况,提出利用M at lab软件的热分析功能进行非饱和土渗流的计算方法,阐述M at lab软件中的PDE(偏微分方程)工具箱在求解计算流体力学问题中的应用过程,算例结果表明应用M at lab软件进行非饱和土渗流场的数值模拟是可行的,可以满足土力学关于渗流的章节教学改革需要。展开更多
While the geodetic excitationχ(t)of polar motion p(t)is essential to improve our understanding of global mass redistributions and relative motions with respect to the terrestrial frame,the widely adopted method to de...While the geodetic excitationχ(t)of polar motion p(t)is essential to improve our understanding of global mass redistributions and relative motions with respect to the terrestrial frame,the widely adopted method to deriveχ(t)from p(t)has biases in both amplitude and phase responses.This study has developed a new simple but more accurate method based on the combination of the frequency-and time-domain Liouville's equation(FTLE).The FTLE method has been validated not only with 6-h sampled synthetic excitation series but also with daily and 6-h sampled polar motion measurements as well asχ(t)produced by the interactive webpage tool of the International Earth Rotation and Reference Systems Service(IERS).Numerical comparisons demonstrate thatχ(t)derived from the FTLE method has superior performances in both the time and frequency domains with respect to that obtained from the widely adopted method or the IERS webpage tool,provided that the input p(t)series has a length around or more than 25 years,which presents no practical limitations since the necessary polar motion data are readily available.The FTLE code is provided in the form of Mat Lab function.展开更多
针对河口与近海生物对环境条件变化响应的非线性和不连续性,以及生态系统所具有的多源性、开放性、耗散性和远离平衡态的复杂特征,利用人工神经网络最新技术,建立了河口滨海区生态需水量与健康生态特征指标间的非线性耦合关系的神经网...针对河口与近海生物对环境条件变化响应的非线性和不连续性,以及生态系统所具有的多源性、开放性、耗散性和远离平衡态的复杂特征,利用人工神经网络最新技术,建立了河口滨海区生态需水量与健康生态特征指标间的非线性耦合关系的神经网络计算模型,借助M at lab工具箱强大功能和自主开发接口,快速实现输入数据的预处理、网络的训练和仿真。展开更多
文摘分析了二维渗流场与二维温度场之间的相似性,基于许多实际工程中的渗流问题都可视为平面应变情况,提出利用M at lab软件的热分析功能进行非饱和土渗流的计算方法,阐述M at lab软件中的PDE(偏微分方程)工具箱在求解计算流体力学问题中的应用过程,算例结果表明应用M at lab软件进行非饱和土渗流场的数值模拟是可行的,可以满足土力学关于渗流的章节教学改革需要。
基金supported by the National Natural Science Foundation of China(grant numbers 41874025 and 41474022)。
文摘While the geodetic excitationχ(t)of polar motion p(t)is essential to improve our understanding of global mass redistributions and relative motions with respect to the terrestrial frame,the widely adopted method to deriveχ(t)from p(t)has biases in both amplitude and phase responses.This study has developed a new simple but more accurate method based on the combination of the frequency-and time-domain Liouville's equation(FTLE).The FTLE method has been validated not only with 6-h sampled synthetic excitation series but also with daily and 6-h sampled polar motion measurements as well asχ(t)produced by the interactive webpage tool of the International Earth Rotation and Reference Systems Service(IERS).Numerical comparisons demonstrate thatχ(t)derived from the FTLE method has superior performances in both the time and frequency domains with respect to that obtained from the widely adopted method or the IERS webpage tool,provided that the input p(t)series has a length around or more than 25 years,which presents no practical limitations since the necessary polar motion data are readily available.The FTLE code is provided in the form of Mat Lab function.
文摘针对河口与近海生物对环境条件变化响应的非线性和不连续性,以及生态系统所具有的多源性、开放性、耗散性和远离平衡态的复杂特征,利用人工神经网络最新技术,建立了河口滨海区生态需水量与健康生态特征指标间的非线性耦合关系的神经网络计算模型,借助M at lab工具箱强大功能和自主开发接口,快速实现输入数据的预处理、网络的训练和仿真。
