检索结果-南通市图书馆

Slope wavenumber spectrum models of capillary and capillary-gravity waves

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Chinese Journal of Oceanology and Limnology 2010年第2期28卷 359-363页

作者：贾永君张杰王岩峰 institute of Oceanology Chinese Academy of Sciences Graduate School Chinese Academy of Sciences First institute of Oceanography State Oceanic Administration

Capillary and capillary-gravity waves possess a random character, and the slope wavenumber spectra of them can be used to represent mean distributions of wave energy with respect to spatial scale of variability. But simple and practical models of the slope wavenumber spectra have not been put forward so far. In this article, we address the accurate definition of the slope wavenumber spectra of water surface capillary and capillary-gravity waves. By combining the existing slope wavenumber models and using the dispersion relation of water surface waves, we derive the slope wavenumber spectrum models of capillary and capillary-gravity waves. Simultaneously, by using the slope wavenumber models, the dependence of the slope wavenumber spectrum on wind speed is analyzed using data obtained in an experiment which was performed in a laboratory wind wave tank. Generally speaking, the slope wavenumber spectra are influenced profoundly by the wind speed above water surface. The slope wavenumber spectrum increases with wind speed obviously and do not cross each other for different wind speeds. But, for the same wind speed, the slope wavenumber spectra are essentially identical, even though the capillary and capillary-gravity waves are excited at different times and locations. Furthermore, the slope wavenumber spectra obtained from the models agree quite well with experimental results as regards both the values and the shape of the curve.

关键词： capillary and capillary-gravity waves slope wavenumber spectrum model wind speeddependence

Description of alpha-clustering of 8Be nucleus states in high-precision theoretical approach

在线全文

学校读者我要写书评

暂无评论

Chinese Physics C 2020年第12期44卷 146-157页

作者： D.M.Rodkin Yu.M.Tchuvil’sky Dukhov Research institute for Automatics 127055MoscowRussia Skobeltsyn institute of Nuclear Physics Lomonosov Moscow State University119991 MoscowRussia

Scrupulous theoretical study of 8Be nucleus states,both clustered and non-clustered,is performed over a wide range of excitation *** quantities that characterize the degree of the alpha-clustering of these states,i.e.,spectroscopic factors,cluster form factors,and alpha-decay widths,are computed in the framework of the developed accurate ab initio *** basic properties of the 8Be spectrum,including the binding and excitation energies and the mean values of the isospin,are calculated *** the majority of instances,the results of the computation turn out to be in good agreement with the spectroscopic data.A number of predictions are made,and corresponding verification experiments are *** of the developed approach for nuclear spectroscopy are demonstrated.

关键词： nuclear clustering nuclear structure light nuclei alpha-spectroscopy ab initio computations

Fault-Diagnosis Method Based on Support Vector Machine and Artificial Immune for Batch Process

在线全文

学校读者我要写书评

暂无评论

Journal of Beijing institute of Technology 2010年第3期19卷 337-342页

作者：马立玲张瞾王军政 School of Automation Beijing Institute of Technology

A new fault-diagnosis method to be used in batch processes based on multi-phase regression is presented to overcome the difficulty arising in the processes due to non-uniform sample data in each *** vector machine is first used for phase identification,and for each phase,improved artificial immune network is developed to analyze and recognize fault patterns.A new cell elimination role is proposed to enhance the incremental clustering capability of the immune *** proposed method has been applied to glutamic acid fermentation,comparison results have indicated that the proposed approach can better classify fault samples and yield higher diagnosis precision.

关键词： fault diagnosis support vector machine artificial immune batch process

OBSERVATION OF SCATTERED ULTRASONIC FIELDS FROM A RIBBON-TYPE CRACK IN SOLID WITH PHOTOELASTIC TECHNIQUE

在线全文

学校读者我要写书评

暂无评论

Science China Mathematics 1986年第12期29卷 1334-1343页

作者：沈建中李明轩应崇福 Academia Sinica Beijing institute of Acoustics

Scattering of plane ultrasonic-wave pulses by a ribbon-type crack is investigated with the photoelastic technique, Photographs of the scattering processes of a longitudinal-wave pulse or a shear-wave pulse incident at various angles are presented and analyzed. The experimental results fairly agree with our theoretical predictions discussed in a previous work on scattering at early stages. The data obtained from the photoelastic observation also show the scattering phenomena at later stages.

关键词： OBSERVATION OF SCATTERED ULTRASONIC FIELDS FROM A RIBBON-TYPE CRACK IN SOLID WITH PHOTOELASTIC TECHNIQUE

Saving Strategy and Simulation Analysis of Green Log Walls in Severe Cold Area

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Journal of Harbin institute of Technology(New Series) 2014年第5期21卷 46-51页

作者： Hong-Peng Xu Si Li School of Architecture Harbin institute of Technology

Log house is a traditional type of vernacular dwelling in Chinese cold area. It contains distinct regional characteristics and architectural cultures. In recent years,log house has come into vogue softly with the development of wood techniques. However,log houses expend too much wood materials. There are also many negative aspects of this type of wood building which go against the criteria of energy conservation,and its high prime cost hinders the application as well. To solve these problems, the paper emphasizes using more environmental standardized techniques which save cost at the same time,and put forward technical strategy to improve the log walls. The optimization schemes are mainly divided into two categories: internal insulation and filled insulation. Each type of insulation is respectively derived two schemes through changing the thickness of main structure layers and insulation layer. Firstly,we use Weto software to calculate the timber volume of the four schemes,and it concludes that all the optimizations can save more timber than the prototype log wall with the section of 200 mm × 200 mm. Secondly,thermal comfort of each scheme is insulated in Design *** results show that thermal insulation of filling type represents better than the other schemes. At last,we use thermal calculating formula to calculate thermal resistance of every scheme. Contrast to the energy efficiency standards of Heilongjiang Province, the data show that the four schemes meet the requirements of the specification.

关键词： sever cold area log wall green wood building thermal comfort simulation

THE PRECURSOR OF INSTABILITY FOR NONLINEAR SYSTEMS AND ITS APPLICATION TO EARTHQUAKE PREDICTION

在线全文

学校读者我要写书评

暂无评论

Science China Chemistry 1991年第8期34卷 977-986页

作者：尹祥础尹灿 institute of Geophysics State Seismological Bureau

By analysing the instability process of various nonlinear systems, we conclude that their instability precursors are the continual heightening of the response rate or response *** this theory to earthquake prediction, we adopt the periodical change of the stress in crust caused by the tide-generating force as the loading and unloading. If we can measure the ratio of the response (such as crust deformation, gravity and seismicity) during the loading period to that during the unloading period, this parameter must contain some characteristic information about the seismogenic *** nine earthquakes (M≥7) data that occurred in Chinese mainland during 1970-1988, we take the sum of square root o?energy of small earthquakes, which is called the released strain by Benioff, as the response to the tidal loading and unloading. We find that the response ratios of seven earthquakes increase obviously before the main earthquakes.

关键词： nonlinear system instability loading and unloading response ratio tidal stress in crust earthquake prediction.

Real time remaining useful life prediction based on nonlinear Wiener based degradation processes with measurement errors

在线全文

学校读者我要写书评

暂无评论

Journal of Central South University 2014年第12期21卷 4509-4517页

作者：唐圣金郭晓松于传强周志杰周召发张邦成 The Second Department High-Tech Institute of Xi’an The Third Department High-Tech Institute of Xi’an School of Mechatronic Engineering Changchun University of Technology

Real time remaining useful life(RUL) prediction based on condition monitoring is an essential part in condition based maintenance(CBM). In the current methods about the real time RUL prediction of the nonlinear degradation process, the measurement error is not considered and forecasting uncertainty is large. Therefore, an approximate analytical RUL distribution in a closed-form of a nonlinear Wiener based degradation process with measurement errors was proposed. The maximum likelihood estimation approach was used to estimate the unknown fixed parameters in the proposed model. When the newly observed data are available, the random parameter is updated by the Bayesian method to make the estimation adapt to the item's individual characteristic and reduce the uncertainty of the estimation. The simulation results show that considering measurement errors in the degradation process can significantly improve the accuracy of real time RUL prediction.

关键词： remaining useful life Wiener based degradation process measurement error nonlinear maximum likelihood estimation Bayesian method

Moderate electron–spin interaction in Fe-intercalated NbSe2

在线全文

学校读者我要写书评

暂无评论

Chinese Physics B 2025年第1期 455-460页

作者：刘乔宇白建利董庆新张黎博程靖雯刘品宇李存东黄宇孙英睿任治安陈根富 institute of Physics and Beijing National Laboratory for Condensed Matter Physics Chinese Academy of Sciences School of Physical Sciences University of Chinese Academy of Sciences Songshan Lake Materials Laboratory

The interaction between charge and spin degrees of freedom has always been the central issue of condensed matter physics, and transition metal dichalcogenides（TMDs） provide an ideal platform to study it benefiting from their highly tunable properties. In this article, the influence of Fe intercalation in NbSe2was elaborately investigated using a combination of techniques. Magnetic studies have shown that the insertion of Fe atoms induces an antiferromagnetic state in which the easy axis aligns out of the plane. The sign reversal of the magnetoresistance across the Neel temperature can be satisfactorily explained by the moderate interaction between electrons and local spins. The Hall and Seebeck measurements reveal a multi-band nature, and the contribution of various phonon scattering processes is discussed based on the thermal conductivity and specific heat data.

关键词：

Variations of Precipitation Structure and Microwave Tbs During the Evolution of a Hailstorm from TRMM Observations

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Acta meteorologica Sinica 2007年第2期21卷 153-167页

作者：何文英陈洪滨 LAGEO institute of Atmospheric Physics CAS

In this paper, a hailstorm occurring on 9 May 1999 in Huanghuai region was studied by using the combined data from the precipitation radar （PR）, microwave image （TMI）, and visible infrared scanner （VIRS） on the Tropical Rainfall Measuring Mission （TRMM） satellite. According to the 3-orbit observations of 5- h duration from the TRMM satellite, the variation characteristics of the precipitation structures as well as cloud top temperature and microwave signals of the precipitating cloud were comprehensively analyzed during the evolution of hailstorm. The results show that the precipitation is obviously converted from early hail cloud with strong convection into the later storm cloud with weak convection. For hail cloud, there exists some strong convective cells, and the heavy solid precipitation is shown at the middle-top levels so that the contribution of rainfall amount above the freezing-layer to the column precipitation amount is rather larger than that within the melting-layer. However, for storm cloud, the convective cells are surrounded by the large area of stratiform precipitation, and the precipitation thickness gradually decreases, and the rainfall above the freezing-layer obviously reduces and the contribution of rainfall amount within the melting-layer rapidly increases. Therefore, the larger ratio of rainfall amount above the freezing layer to column precipitation amount is, the more convective the cloud is; reversely, the larger proportion of rainfall below the melting layer is, the more stable the stratiform cloud is. The different changing trends of microwave signals at different precipitation stages show that it is better to consider the structures and stages of precipitating cloud to choose the optimal microwave channels to retrieve surface rainfall.

关键词： Tropical Rainfall Measuring Mission (TRMM) precipitation radar (PR) hailstorm precipitation structure microwave brightness temperature