繞射計 的英文怎麼說
中文拼音 [ràoshèjì]
繞射計
英文
diffractometer-
The model is based on the theory of physical optics ( po ), geometry theory of diffraction ( gtd ) and uniform theory of diffraction ( utd ), and it can compute and analyze the propagation of em wave in microcellular environments by using improved ray tracing method
該模型基於物理光學( po ) 、幾何繞射理論( gtd ) 、一致性繞射理論( utd ) ,利用改進的射線跟蹤法對微蜂窩中電波傳播特性進行了數值分析計算。Since the problem of feature extraction from 2 - d radar data can be approached as a parametric modeling and parameter estimation problem, the 2 - d type - discriminated geometric theory of diffraction based ( td - gtd ) model that discriminate between the localized and distributed scattering centers of the target is presented
在對目標散射中心的建模與參數估計中,提出採用更貼近散射機理的、特徵含量更為豐富的二維散射中心模型?區分局域性與展布式散射中心類型的幾何繞射理論( td - gtd )模型。A radiometer consists of four vanes free to rotate about a pivot inside a bulb containing air at very low pressure.
輻射計是在充有很低壓強氣體的球泡內,裝置能繞支點自由旋轉的四個葉片。In order to obtain the complex rcs of the target quickly in high frequency band, the graphical electromagnetic computing software, greco, is used. the modification of the computing kernel code is presented. the judgement of edges of complex targets is more sufficient and the computation of edge wave based on physical theory of diffraction ( ptd ) is more exact after the modification
為了可以準確地預估雷達目標的rcs ,我們對于航天部207所的圖形電磁計算軟體( greco )進行了進一步的開發與包裝,用borland公司的c + + builder開發了更加易於使用的基於windows操作系統的新版greco ,並且在考察了原有的greco計算內核之後,結合計算機圖形學方面的理論,對greco的內核代碼進行了改進,整體上使得邊緣繞射場的計算結果更加準確。The hydrauli c model of gradual dike - break simulates numerically the 2 - d flow of gradual dike - break waves. it shows the variation of flow field on breach, and the complicated flow characteristic of the propagation, diffraction, reflection and deformation of the dike - break waves. the hydraulic model can realistically simulate the burst process of dike, and computational accuracy is satisfied with the engineering demands
本文建立逐漸潰堤的水力模型首次對二維逐漸潰堤波的流動問題進行了數值研究,揭示了逐漸潰堤過程中潰口處流場的變化情況,以及潰堤波的傳播、繞射、反射及變形的復雜運動特徵,能較好地模擬實際工程中的潰堤失事,模擬比較逼近於真實潰決過程,計算精度可滿足工程要求。The calculated drafts covers the whole possible ship draft in the large amplitude motion ; secondly, the research creates and solves the ship large amplitude motion equations. on the one hand, the actual calculation takes into account the coupling between the different motion modes, on the other hand, in the process of calculation of the ship hydrodynamic coefficient, it considers the influence of the nonlinear factor. the hydrodynamic coefficient used in the calculation of froude - krylov force, diffraction force and radiation force changes instantaneously following the draft, and the hydrostatic buoyancy is computed very accurately for the instantaneous immerse hull
本文的研究分為二個部分:首先利用frank源匯法計算水動力系數,計算包括不同吃水時的附加質量和阻尼系數,吃水范圍涵蓋了船舶大幅度運動時所有可能的吃水;然後建立和求解船舶大幅度運動方程,在實際計算時一方面考慮了運動模態之間的耦合,另一方面在計算水動力時,考慮了非線性因素的影響。 froude - krylov力、輻射力、繞射力中的水動力系數隨吃水瞬時變化,靜浮力的計算精確到船體瞬時濕表面積,最後用四階龍格?庫塔方法在時域內求解船舶運動方程,並進行了載荷計算。After solution of radiational and diffractional fluid field of asymmetrical sections by applying the multipole expansion method, wave loads on damaged ships are calculated by the linear strip theory under the non - upright floating condition, taking the effect on the heel angle and trimming angle caused by the damaged tank inundation below waterline into account
然後採用線性切片理論,計及水線以下破損后船舶由於艙室進水產生的橫傾角與縱傾角的影響,利用多級展開法求解非對稱剖面的二維輻射和繞射流場,計算了破損船體非正浮狀態條件下的波浪載荷。At present greco is regarded as one of the most valuable methods of radar cross section ( rcs ) computation in the high - frequency region. depending on these conditions, several researches have been completed in this paper : firstly, calculating rcs of complex conducting targets has been accomplished by greco method. the high - frequency rcs of targets are obtained through physical optics ( po ) and incremental length diffraction coefficients ( ildc ) respectively
本論文做了以下研究工作:首先,實現了運用greco方法計算了高頻區理想導體復雜目標的雷達散射截面( rcs ) ,分別應用了物理光學法( po )和增量長度繞射系數法( ildc )計算了目標的面元和棱邊的電磁散射,最後綜合面元與棱邊的散射效應得到目標的總rcs 。Abstract : the effects of airfoil geometric parameters on wing " s spacial and polarized scattering characteristics have been systematically revealed. the results of the study indicated that the calculating value of diffraction from trailing edge by using the formula of the straight wedge is very far from experimental results for vertical polarization, and the contribution of thickness of the trailing edge to scattering must be considered in the calculation. the scattering peak of leading edge depends only on radius of airfoil for horizontal polarization. but for vertical polarization, it depends on maximum thickness and the location of maximum thickness. engineering formulas for evaluating all scattering peaks were given in the paper. it is important for the design of low - rcs wing
文摘:系統地揭示了翼形幾何參數對機翼的空間散射特性、極化散射特性的影響規律.研究發現,在垂直極化狀態下用理論尖劈公式計算機翼后緣繞射的計算結果與實驗結果相差甚遠.提出在垂直極化狀態下機翼后緣繞射的計算必須將后緣厚度考慮在內的見解.對於水平極化,前緣散射波峰只與前緣半徑有關;而對於垂直極化,前緣散射波峰與翼形最大厚度以及最大厚度位置有關.給出前後緣散射波峰的工程估算公式,為低雷達散射截面( rcs )機翼設計提供依據Incremental length diffraction coefficients ( ildc ) is adopted to calculate the contribution of edge diffraction. in order to improve the accuracy of calculation, multi - scattering is discussed, based on the two former contributions and ray - tracing method. geometrical optics ( go ) and physical optics ( po ) are used to calculate the multi - reflection between facets and facets
對于鏡面反射採用物理光學法計算其散射貢獻,結合基於面元的目標模型的表示,採用離散的積分形式,將面電流積分化簡為線積分,簡化計算復雜度;對于邊緣繞射,運用增量長度繞射系數理論計算目標邊緣繞射場;在多次反射中,則以光線跟蹤方法為基礎,採用幾何光學、物理光學相結合的方法分析考慮多次散射場。The text even explores the method to build the building database and computes the field intensity based on geometrical optics and consistency diffraction theory
本文還探索了自動建立建築物數據庫的方法,基於幾何光學和一致性繞射理論對跟蹤射線的場強進行了計算。Calculation of time domain of second order wave diffraction in three dimensions with finite element method
三維二階水波繞射問題的有限元時域計算The numerical model is tested by computing wave field for several examples of laboratory experiment, and agreement between model results and available experimental data is found to be quite reasonable, which demonstrates the model ' s ability to simulate wave shoaling, refraction, diffraction and reflection
用多個實驗地形對本文模型進行了驗證,計算結果與實測數據吻合很好,反映了本文模型可以較好地模擬波浪傳播過程中的淺水變形、折射、繞射和反射等波浪變形現象。On the basis of this analysis the radiation and diffraction forces of the ship are calculated using these three methods and compared. at the same time vertical ship motions in regular wave are solved by these three methods. the results are compared to test each method ' s availability and suitability, thus the theoretical basis of optimize design of sea - keeping performance is provided
分別介紹了二維切片法、高速細長體理論和三維理論的基本原理,分析了三種不同方法各自的適用性,在此基礎上分別計算了船舶的輻射力和繞射力,比較了這三種方法的計算結果,為不同營運目的的船舶耐波性計算提供陜速有效而實用的計算方法;同時應用三種方法計算了船舶在規則波中的垂向穩態運動響應,比較三種方法的計算結果,測試各種方法的有效性和適用性,為船舶耐波性的優化設計提供原始的理論基礎; 2Secondly, the precision of diffraction field of the edges of targets has been greatly advanced by improving the original method of detecting edges
其次,改進了原先的棱邊檢測方法,使得棱邊繞射場的計算精度大大提高。The exact location of reflection and diffraction points is essential in order to calculate the polarization components of the reflected and diffracted fields and their trajectories. then, a vector addition of the received fields is carried out to obtain the total received field strength and, subsequently, the path loss along a predetermined route
該模型基於幾何光學理論、一致性幾何繞射理論和鏡像理論,通過大量的反射和繞射射線軌跡得出源點至場點的多條路徑,然後由矢量計算求出各場點處的路徑損耗。Computation of first - order wave force was simplified, and second - order wave force included second diffraction of second - order incident wave
對一階波浪力計算進行了進一步的簡化,在二階力的波浪力計算中考慮了二階入射波的二次繞射。An idea to establish a cancellation database on the basis of the smooth of rcs of the protected target is also introduced the field scattered by facets and fringes and the multiple scattering effect are calculated by a hybridization of the theory of physical optics, equivalent currents and areal projection - physical optics, which are utilized to compute the rcs of an aeroplane
還提出了根據被保護目標rcs的平滑值確定對消數據庫的思想。應用物理光學法、等效電磁流法和區域投影物理光學方法計算了面元散射場、劈邊緣繞射場以及多次散射場,採用此方法計算了某飛機的rcs ,並對該目標的rcs進行了平滑處理。We study about how to improve the accuracy of calculating the field energy. such as high order diffracted field, hybrid method, and so on. and getting some useful conclusion
研究了提高觀測點場強計算精度的一些方法,如加入高階繞射、混合演算法等,並對此作了一些有益的探討。The patent covers the use of a computer - designed diffraction grating, a type of hologram that takes a single beam and breaks it up into an array of beams, each one of which forms an optical trap for particles of micron or nanometer dimensions
此專利涵蓋了電腦設計的繞射光柵,以及可將單一光束分散成陣列光束的雷射全像術,其中每道光束都會形成光阱,可捕捉微米或奈米大小的粒子。分享友人