本文综述了二次离子质谱(Secondary Ion Mass Spectroscopy,SIMS)溅射深度剖析的发展历史,介绍了SIMS溅射深度剖析的定量分析方法。对两个最常用于SIMS溅射深度剖析定量分析的理论模型——Hofmann提出的MRI(Mixing-Roughness-Informatio...本文综述了二次离子质谱(Secondary Ion Mass Spectroscopy,SIMS)溅射深度剖析的发展历史,介绍了SIMS溅射深度剖析的定量分析方法。对两个最常用于SIMS溅射深度剖析定量分析的理论模型——Hofmann提出的MRI(Mixing-Roughness-Information depth)模型和Dowsett等人提出的响应函数进行了对比分析。展开更多
在控制系统仿真建模中,对于步进电机这一重要功能的准确建模和研究至关重要,对一般步进电机的建模过程进行分析,并利用MATLAB中的动态仿真工具Simulink以及它提供的基于Sim Power System仿真引擎,建立二相混合式步进电机的动态仿真模型...在控制系统仿真建模中,对于步进电机这一重要功能的准确建模和研究至关重要,对一般步进电机的建模过程进行分析,并利用MATLAB中的动态仿真工具Simulink以及它提供的基于Sim Power System仿真引擎,建立二相混合式步进电机的动态仿真模型,通过分析仿真结果来验证所建立的模型的有效性和适用性。展开更多
We present new quantitative model describing the pressure dependence of acoustic P-and S-wave velocities.Assuming that a variety of individual mechanisms or defects(such as cracks,pore collapse and grain crushing)can ...We present new quantitative model describing the pressure dependence of acoustic P-and S-wave velocities.Assuming that a variety of individual mechanisms or defects(such as cracks,pore collapse and grain crushing)can contribute to the pressure-dependent change of the wave velocity,we order a characteristic pressure to all of them and allow a series of exponential terms in the description of the(Pand S-waves)velocity-pressure function.We estimate the parameters of the multi-exponential rock physical model in inversion procedures using laboratory measured P-and S-wave velocity data.As is known,the conventional damped least squares method gives acceptable results only when one or two individual mechanisms are assumed.Increasing the number of exponential terms leads to highly nonlinear ill-posed inverse problem.Due to this reason,we develop the spectral inversion method(SIM)in which the velocity amplitudes(the spectral lines in the characteristic pressure spectrum)are only considered as unknowns.The characteristic pressures(belonging to the velocity amplitudes)are excluded from the set of inversion unknowns,instead,they are defined in a set of fixed positions equidistantly distributed in the actual interval of the independent variable(pressure).Through this novel linear inversion method,we estimate the parameters of the multi-exponential rock physical model using laboratory measured P-and S-wave velocity data.The characteristic pressures are related to the closing pressures of cracks which are described by well-known rock mechanical relationships depending on the aspect ratio of elliptical cracks.This gives the possibility to estimate the aspect ratios in terms of the characteristic pressures.展开更多
文摘本文综述了二次离子质谱(Secondary Ion Mass Spectroscopy,SIMS)溅射深度剖析的发展历史,介绍了SIMS溅射深度剖析的定量分析方法。对两个最常用于SIMS溅射深度剖析定量分析的理论模型——Hofmann提出的MRI(Mixing-Roughness-Information depth)模型和Dowsett等人提出的响应函数进行了对比分析。
文摘在控制系统仿真建模中,对于步进电机这一重要功能的准确建模和研究至关重要,对一般步进电机的建模过程进行分析,并利用MATLAB中的动态仿真工具Simulink以及它提供的基于Sim Power System仿真引擎,建立二相混合式步进电机的动态仿真模型,通过分析仿真结果来验证所建立的模型的有效性和适用性。
基金supported by the European Union,co-financed by the European Social Fund and the GINOP-2.315-2016-00010"Development of enhanced engineering methods with the aim at utilization of subterranean energy resources"project in the framework of the Szechenyi 2020 Plan,funded by the European Union,co-financed by the European Structural and Investment Funds。
文摘We present new quantitative model describing the pressure dependence of acoustic P-and S-wave velocities.Assuming that a variety of individual mechanisms or defects(such as cracks,pore collapse and grain crushing)can contribute to the pressure-dependent change of the wave velocity,we order a characteristic pressure to all of them and allow a series of exponential terms in the description of the(Pand S-waves)velocity-pressure function.We estimate the parameters of the multi-exponential rock physical model in inversion procedures using laboratory measured P-and S-wave velocity data.As is known,the conventional damped least squares method gives acceptable results only when one or two individual mechanisms are assumed.Increasing the number of exponential terms leads to highly nonlinear ill-posed inverse problem.Due to this reason,we develop the spectral inversion method(SIM)in which the velocity amplitudes(the spectral lines in the characteristic pressure spectrum)are only considered as unknowns.The characteristic pressures(belonging to the velocity amplitudes)are excluded from the set of inversion unknowns,instead,they are defined in a set of fixed positions equidistantly distributed in the actual interval of the independent variable(pressure).Through this novel linear inversion method,we estimate the parameters of the multi-exponential rock physical model using laboratory measured P-and S-wave velocity data.The characteristic pressures are related to the closing pressures of cracks which are described by well-known rock mechanical relationships depending on the aspect ratio of elliptical cracks.This gives the possibility to estimate the aspect ratios in terms of the characteristic pressures.
