共查询到20条相似文献,搜索用时 93 毫秒
1.
2.
3.
4.
合理安排实验,溶概念于其中凌亚文(陕西机械学院,西安710048)物理实验课是一门基础性的实验课程,是学生进入大学以后所遇到的第一门实验课.它是以自学为主,通过实验不仅可以提高学生的动手能力,还应通过对实验结果的分析、总结,达到对某些概念的进一步理解... 相似文献
5.
6.
7.
8.
9.
10.
语音波形过零率是一个很重要的语音特征.它通常是语音端点判别和音素粗分类的基本要素.但是,它也有不稳定的一面,所以很少看到有人将它用到语音细分类和识别中.本文提出了把一串过零点间时间间隔作为辨认普通话声母的语音特征的方法.本文做了以过零点间时间间隔作为HMM的输入符号,对送气塞音类声母P、T、K,不送气塞擦音Z、ZH和喉擦音H等六个声母进行辨认实验.在连机的环境下,我们取得78%的声母正确辨认率.以过零点间时间间隔作为语音特征的优点是计算简单,易于实现.此外,它可以不经转换直接作为离散HMM的输入符号.本文介绍过零点间时间间隔的计算方法和使用HMM对上述六个声母进行识别的实验过程. 相似文献
11.
Al、Cu、Ta高压熔化曲线的理论计算 总被引:1,自引:0,他引:1
由位错熔化理论和不同的静高压实验数据优化的体模量(B0)、剪切模量(G0)及它们对压力的一阶偏导数(B′0、G′0)值计算了Al、Cu、Ta的高压熔化曲线.理论计算的Al、Cu高压熔化曲线与静、动高压实验值较为吻合,Ta的理论高压熔化曲线与动高压实验结果一致,但与静高压实验结果相差较大. 相似文献
12.
Towards predictive combustion kinetic models: Progress in model analysis and informative experiments
Bin Yang 《Proceedings of the Combustion Institute》2021,38(1):199-222
One of the key tasks of combustion chemistry research is to develop accurate and robust combustion kinetic models for practical fuels. An accurate and robust kinetic model yields predictions that are highly consistent with experimental measurements over a wide range of operating conditions, with prediction uncertainties that are acceptable. Reliable experimental data generated by various powerful diagnostic techniques continue to play an essential role in the development of such models. This review focuses on the contributions of synchrotron-based species measurements in combustion systems, on model validation, model structure development, and model parameter optimization. Special emphasis is placed on recently reported strategies for informative and reliable experimental data generation, including combustion kinetic model input parameter evaluation, computational cost reduction for model analysis, model-analysis-based experimental design, experimental data treatment and error reduction. Particularly, the active-subspace-based method (ASSM) can reduce the dimensionality of combustion kinetic models and the aritificial-neural-network-based surrogates (ANN-HDMR and ANN-MCMC) can reduce the computational cost significantly. Global-sensitivity-based experimental design methods including sensitivity entropy and surrogate model similarity (SMS) can guide kinetics-information-enriched experimental data generation. Model-analysis-based calibration for experimental errors and feature extraction of experimental targets can improve the experimental data quality. A computational framework (OptEx) enabling the integration of experimental data with mechanism development, experimental design and model optimization, provides a new means to develop reliable kinetic models more efficiently and effectively. 相似文献
13.
针对在传统示波器的使用实验教学过程中学时相对较短、实验操作不规范及实验仪器存在系统误差导致实物实验教学效果不佳的问题,与实物实验相结合,通过Proteus VSM提供的虚拟示波器进行多种频率比与不同相位差情况下的李萨如图形观察实验,可更加直观方便地学习测量正弦振动频率的方法,加深理解互相垂直振动合成理论。这种将实物实验与虚拟仪器实验相结合的实验教学方法,显著改善了示波器的实验教学效果。 相似文献
14.
夫兰克-赫兹实验教学的发展与完善 总被引:2,自引:1,他引:1
根据不同时期对夫兰克-赫兹实验仪的改进及对实验内容的改革扩充,阐述了该实验教学的不断发展与完善.重点介绍了对第一代夫兰克-赫兹实验的改造,增加了数据采集、电脑显示及数据处理等功能,实现集模拟与数字化为一体的实验装置. 相似文献
15.
16.
光学虚拟实验系统研究 总被引:1,自引:0,他引:1
采用MATLAB技术,结合光学实验教学内容的特点,利用面向对象的方法开发构建了光学虚拟实验系统。该系统具有操作简单、界面直观、实验快速实施等特点。以空间滤波实验和偏振光实验为例,给出了设计思想和相应的仿真实现结果。学生通过对实验系统的操作,可以很快地掌握实验原理、内容和实验特点。该系统作为传统光学实验教学的补充,能够完成一般光学实验中难以实现的实验操作,使复杂的实验操作变得直观生动,提高了光学实验教学的效果,同时也为相关实验系统的设计研发提供了一条新的途径。 相似文献
17.
在ADS散裂靶系统的优化设计中,蒙特卡罗方法结合可靠的散裂反应理论模型进行中子学计算具有重要的作用。本工作利用Geant4程序中的INCLXX模型、BIC模型以及BERT模型和FLUKA程序分别模拟了597 MeV和1 500 MeV质子轰击薄铅靶不同出射角度的中子双微分截面,500,1 500 MeV质子轰击厚铅靶不同出射角度的中子双微分产额,以及400,600,800,1 000和1 200 MeV质子轰击厚钨靶在反角方向(175 °)的中子双微分产额,并与实验数据进行比较。研究表明,对于薄铅靶,Geant4程序的INCLXX模型和FLUKA程序模拟结果与实验符合得更好。能量在10~40 MeV范围内,BIC模型模拟结果明显高于实验数据,而BERT模型模拟结果略微低于实验数据。对于厚铅靶,在40 MeV左右所有的模拟结果都低于实验数据。对于厚钨靶,Geant4程序的BIC模型和FLUKA程序与实验数据符合得较好,INCLXX模型在能量高于60 MeV时模拟结果低于实验数据,BERT模型与实验数据差异较大。总体来看,Geant4程序的INCLXX模型和FLUKA程序进行ADS散裂靶相关的中子学的计算是合理和可靠的。The reliable Monte Carlo simulation codes coupled with nuclear reaction models play an important role in the neutronic calculation for the design and optimization of the ADS spallation target. In this work, the double differential cross sections at different angles produced from a thin lead target bombarded with 597 and 1 500 MeV protons, the neutron energy spectra at different angles produced from a thick lead target bombarded with 500 and 1 500 MeV protons, and the neutron energy spectra in the backward direction(175°) produced from a thick tungsten target bombarded with 400, 600, 800, 1 000 and 1 200 MeV protons are calculated with the Geant4 code coupled INCLXX, BIC and BERT models and the FLUKA code. The calculations are compared with the available experimental data. The results show that, for the thin lead target, the calculations with the Geant4 coupled INCLXX model and FLUKA code well reproduce the experimental results. In a energy range from 10 to 40 MeV, BIC model obviously overestimates the experimental results, and BERT model slightly underestimates the experimental results. For the thick lead target, all of the calculations underestimate the experimental results around 40MeV. For the thick tungsten target, the Geant4 coupled BIC model and FLUKA code well reproduce the experimental results. INCLXX model underestimates the experimental results above 60 MeV. BERT model bad reproduces the experimental results. Overall, the neutronic calculations with the Geant4 code coupled INCLXX model and FLUKA code for the ADS spallation target is reasonable and reliable. 相似文献
18.
19.
Global and local level density models 总被引:1,自引:0,他引:1
20.
The existing measurements of quarkonium polarization in proton-antiproton and proton-nucleus collisions are puzzling. We highlight issues which are often underestimated in the experimental analyses: the importance of the choice of the experimental acceptance on the comparison between experimental measurements and theoretical calculations. New measurements must provide more detailed information, such that physical conclusions can be derived without relying on model-dependent assumptions. We also describe a frame-invariant formalism which minimizes the dependence of the measurements on the experimental acceptance, facilitates the comparison with theoretical calculations, and probes systematic effects due to experimental biases. 相似文献