lattice density 中文意思是什麼
lattice density
解釋
點陣密度-
Abstract : the effect of correction of self - consistent potential on electronic structure in simple cubic nanocrystal particles is calculated by means of the green ' s function method in the tight - binding approximation, taking only the nearest neighbor matrix elements into account. the numerical results show that the electronic energy spectrum is shifted, the chemical potential is not equal to the atomic energy level, the electronic density at each lattice point is changed, and the variation of electronic density at surface lattice point is the largest
文摘:在緊束縛近似下，只計及最近鄰的矩陣元，採用格林函數計算了自洽勢修正對簡立方納米晶體顆粒的電子結構的影響，發現電子能譜發生了移動，化學勢不等於格點原子能級，各格點的電子密度也發生了變化，其中以表面格點的電子密度變化最大。 -
The elastic constants of bcc li, na and fcc al crystals have been evaluated as functions of pressure and temperature by using a new model together with ab initio electronic structure and total - energy calculations. in the model it is considered that the elastic constants of crystals at a given temperature and pressure can be calculated using a conventional density functional method but modified by a new set lattice constants due to the isobaric volumetric thermal expansion when temperature rise from absolute zero to the given one
本文對高壓及有限溫度立方金屬彈性常數的計算方法進行了研究，建立了一種考慮溫度效應的物理模型，基於這個模型和從頭算方法，對典型的立方晶系金屬li 、 na 、 al在高壓及有限溫度（熔點以下溫度）彈性常數進行了計算，取得了與已有實驗結果較好相符的計算結果。 -
Secondllv in the 1 d random traffic flow model. the relation function between the correlation and the creation. disappearance. brake probabilities of the vehicles is presented. according to the statistical mechanical approach to the spatial correlation functions. the theoretical results agree with that of the computer simulation. thirdh. based on the bml model. a main - road traffic flow model with two speeds on two dimensions is designed. this model simulate the traffic situation of one main road and several branches in the cit traffic lights placed on the crossing. vehicles breaking ~ vhile running and turning to other direction while jamming. we investigate the ~ ' e1ocitv and flo ~ ~ of the model when the initial densitvthe brake and turning probabilities. the green to signal rati3. thc number of the branches and the period of the signal are changed. then the reasons causing all the kinds of phenomena are analvzed. finallv. we simulate the bml model using the method of lattice boltzmann which ~ vas brought out by liu mu - renand obtain the velocity - density graph similar to the previous result. the upper critical densiw above which there are oniv jamming configurations. and the lo ~ ver critical density below which there are only moving configurations are the same as before. the boltzmann function which is on the lattices shows the moving and jaxmning transition obviouslv. thus it proves the possibilit of this method on the traffic research
接著，建立了和研究了二維二速的主幹道模型，該模型模擬了城市交通中一條主幹道，多條支道的交通情況，在幹道與支道的交叉路口設置紅綠燈，車輛在運行中可以有對突發事件發生反應的剎車，在發生堵塞時，路口的車輛可考慮通過轉向來緩解交通等各種實際情況的發生，給出了車輛演化的演化方程，並通過計算機模擬，研究模型在改變車輛的初始密度、剎車概率、轉向概率、支道數、紅綠燈信號的綠信比、紅綠燈信號周期等各種情況下支、主幹道車輛的速度、流量的變化，並分析在各種情況下交通狀況的成因，提出改善交通的有效措施。最後，在劉慕仁提出的用格子boltzmann方法研究一維決定論交通流的思路下，將此法推廣到對二維bml模型的模擬上，得到了與用以往方法的研究結果相類似的速度-密度圖線，且車輛從運動相到堵塞相轉變的上下臨界密度是一致的，同時分別給出車輛在處于暢通相和堵塞相時， boltzmann函數在格子上的分佈情況，進一步驗證了此法的可行性。 -
In the theoretical simulation on the behavior of single helium atom in aluminum, the varieties of energy data including the formation, migration, binding, and dissociation energies for single helium atom at the interstitial, vacancy, grain boundary, and dislocation sites in aluminum lattice were calculated, based on the density functional theories, general gradient approximation and pseudopotential plane wave method. results showed that the most fittable sites for containing helium atoms inside the cell are vacancies. but in the view of the whole lattice, grain boundaries are the best
計算結果表明，晶內he原子擇優佔位區是空位，而在整個晶體范圍，最有利於容納he原子的區域是晶界，位錯容納he原子的能力次於晶界和空位；在fcc -鋁的間隙位中， he原子優先充填四面體間隙位；晶內間隙he原子是可動的，通過間隙he原子的運動，可在晶內聚集，或被空位、晶界、位錯等缺陷束縛。 -
Chapter 4 proposes an incompressible lattice bgk model, in which the velocity and pressure instead of the mass density that is a constant are the independent dynamic variables
本文第四章建立了以壓力、速度為獨立變量的不可壓格子bgk模型。
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