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191.
It is now feasible to predict accurately the structural energies of solids and solid surfaces from first principles computational techniques based on pseudopotential theory. We illustrate these techniques for several prototypical systems. We predict structural properties for binary crystalline systems of the form: ANB8–N where (A, B) are simple metals and metalloids and N is the number of valence electrons on A. We illustrate the chemical forces responsible for stabilizing rocksalt, zinc blende, and white tin structures as a function of pressure. Also we demonstrate the utility of these techniques for predicting the surface properties for insulators and transition metals. 相似文献
192.
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194.
In this paper,using a nonlinear low-order barotropic system with orography and momentum forcing aswell as dissipation,we have theoretically calculated the two kinds of curves for the seasonal northward movementof subtropical highs.It has been shown that the theoretical results resemble basically with the analysed resultsof wave spectrum data. 相似文献
195.
Predictability of the atmosphere 总被引:7,自引:0,他引:7
Chou Jifan 《大气科学进展》1989,6(3):335-346
This paper makes a review on the predictability of the atmosphere. The essential problems of predictability theo-ry, i.e., how a deterministic system changes to an undeterministic system (chaos) and how is the opposite (order within chaos), are discussed. Some applications of predictability theory are given. 相似文献
196.
197.
Analogue Correction Method of Errors by Combining Statistical and Dynamical Methods 总被引:1,自引:0,他引:1
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Based on the atmospheric analogy principle, the inverse problem that the information of historical analogue data is utilized to estimate model errors is put forward and a method of analogue correction of errors (ACE) of model is developed in this paper. The ACE can combine effectively statistical and dynamical methods, and need not change the current numerical prediction models. The new method not only adequately utilizes dynamical achievements but also can reasonably absorb the information of a great many analogues in historical data in order to reduce model errors and improve forecast skill. Furthermore, the ACE may identify specific historical data for the solution of the inverse problem in terms of the particularity of current forecast. The qualitative analyses show that the ACE is theoretically equivalent to the principle of the previous analogue-dynamical model, but need not rebuild the complicated analogue-deviation model, so has better feasibility and operational foreground. Moreover, under the ideal situations, when numerical models or historical analogues are perfect, the forecast of the ACE would transform into the forecast of dynamical or statistical method, respectively. 相似文献
198.
Strategy and methodology of dynamical analogue prediction 总被引:8,自引:0,他引:8
In order to effectively improve numerical prediction level by using current models and data, the strategy and methodology of dynamical analogue prediction (DAP) is deeply studied in the present paper. A new idea to predict the prediction errors of dynamical model on the basis of historical analogue information is put forward so as to transform the dynamical prediction problem into the estimation problem of prediction errors. In terms of such an idea, a new prediction method of final analogue correction of errors (FACE) is developed. Furthermore, the FACE is applied to extra-seasonal prediction experiments on an operational atmosphere-ocean coupled general circulation model. Prediction results of summer mean circulation and total precipitation show that the FACE can to some extent reduce prediction errors, recover prediction variances, and improve prediction skills. Besides, sensitive experiments also show that predictions based on the FACE are evidently influenced by the number of analogues, analogue-selected variables and analogy metric. 相似文献
199.
The neutrino luminosity by the ordinary URCA process in a strongly magnetized electron gas is computed. General formulae are presented for the URCA energy loss rates for an arbitrary degree of degeneracy. Analytic expressions are derived for a completely degenerate, relativistic electron plasma in the special case of neutron-proton conversion. Numerical results are given for more general cases.The main results are as follows: the URCA energy loss rates are drastically reduced for the regime of great degeneracy by a factor up to 10–3 for 1, andT
910, where =H/H
q
,H
q
=m
2
c
3/eh=4.414×1013 G. In the non-degenerate regime the neutrino luminosity is enhanced approximately linearly with for the temperature range 1T
910. Possible applications to white dwarfs and neutron stars are briefly discussed.We have been recently informed that in Gamow home-dialect (Odessa dialect) URCA means thief — (Private communication from Prof. G. Wataghin). 相似文献
200.
Li-Da Xing Jin Ba Martin G.Lockley Hendrik Klein Sheng-Wu Yan Anthony Romilio Chun-Yong Chou W.Scott Persons IV 《古地理学报》2018,(1)
Upper Triassic and Middle Jurassic strata of the Xichang Basin in Sichuan Province, southwestern China, yielded important dinosaur ichnofossils. From the Xujiahe Formation of the Yiguojiao tracksite, we report a Late Triassic footprint assemblage in China and the first discovery of diagnostic Triassic sauropodomorph tracks in this region. The tracks share a number of features in common with the ichnogenera Eosauropus(Late Triassic) and Liujianpus(Early Jurassic). The neighboring Bingtu tracksite is stratigraphically younger(Shaximiao Formation, Middle Jurassic) and preserves small tridactyl theropod tracks that represent the first occurrence of the ichnotaxon Carmelopodus in China and Asia. While these tracks are morphologically comparable to those from the Middle Jurassic type locality in North America, the specimens from China show the proximal margin of the digit IV impression in a more cranial position, which may indicate a trackmaker with a relatively short metatarsal IV. In addition to the skeletal record, the Carmelopodus footprints document the presence of small theropods in the dinosaur fauna of the Middle Jurassic Shaximiao Formation. 相似文献