數值擴散 的英文怎麼說
中文拼音 [shǔzhíkuòsǎn]
數值擴散
英文
numerical diffusion-
The numerical method for the inverse problem of second - dimensional advection - dispersion - reaction equations is discussed in the article
摘要討論了一類二維對流反應擴散方程反問題的數值解法。It further discusses the operation mechanism of the system of agrotechnical diffusion and indicates that the essence of technical diffusion is information diffusion, and the system depends on the course which information flows from the fountainhead to the receivers. and it analyzed the ingredients which influence the information flowing in the system. intruding shannon ’ s information
進一步探討了農業技術擴散系統的運行機制，並指出，技術擴散實質是信息的傳播，是建立在信息從信息源到接收者之間的流動過程，對技術推廣系統中影響信息流動的因素進行分析，引入shannon的信息熵計算方法，對信息接受者的信息接收含量進行測度，通過對所得的數值進行比較，運用定量與定性分析相結合的方法證明技術推廣活動的效率。The diffusion welding behavior of single - crystalline cu to single - crystalline - aio with a nb film interlayer and the joint microstructure properties were studied by tem, sem / eds analyses and four - point bend testing. the nb film interlayer deposited by electron beam evaporation on the ceramic side prior to diffusion welding was found to be olycrytalline and fiber - textured after diffusion bonding, with the close - packed plane ( 110 ) being parallel to the ( 0001 ) basal plane of - aio
擴散連接技術是一門邊緣科學，涉及材料、擴散、相變、界面反應、接頭應力應變等各種行為，工藝參數多，雖然已經進行了大量的試驗研究，但卻對各種材料的連接機理尚未有明確的認識，為此人們試圖藉助于計算技術，對接頭行為進行數值模擬，以便找到共同規律，對擴散連接過程及質量進行預測與實時控制。Field observations and physical models may be used to investigate pollutant transportation and dispersion within urban canyons and validate numerical models. on the other hand, validated numerical models are often applied to simulate in detail atmospheric dispersion within the urban canopy. the numerical results in combination with physical model and or field data may be used to assess urban air quality and support decisionmaking for pollution control strategies and traffic planning
外場觀測和物理模擬可以考察街谷內污染物的傳輸擴散規律並對數值模式進行檢驗，另外，復雜的數值模式則可對城市冠層內大氣擴散問題進行詳細模擬，數值模擬和外場觀測及物理模擬相配合，可用於環境質量評價污染控制決策及交通規劃。Field observations and physical models may be used to investigate pollutant transportation and dispersion within urban canyons and validate numerical models. on the other hand, validated numerical models are often applied to simulate in detail atmospheric dispersion within the urban canopy. the numerical results in combination with physical model and or field data may be used to assess urban air quality and support decision ? ? making for pollution control strategies and traffic planning
外場觀測和物理模擬可以考察街谷內污染物的傳輸擴散規律並對數值模式進行檢驗，另外，復雜的數值模式則可對城市冠層內大氣擴散問題進行詳細模擬，數值模擬和外場觀測及物理模擬相配合，可用於環境質量評價污染控制決策及交通規劃。Finally, some simplification methods to the model were studied and a modified block elimination contraposing the features of the model ' s linear system was developed, which can greatly decrease the model ' s requirement to computer resources. in the second part, numerical methodology of hybrid techniques was developed, which uses dfn models developed in the fist part to build continuum approximations of fractured rock
第三，本文將一種用離散的水?氣分界面模擬非飽和滲流的數值模型擴展到裂隙網路中，為用本文所構建的離散裂隙網路模型模擬裂隙巖體成富擁要柳廳錄非飽和滲流提供了一個初步的框架。The diffusion model and numerical simulation model for chaff clouds are modeled on the assumption that the speed of air where chaff locates is a winner random process and the mass of chaff is zero so it can trace the atmosphere speed very well
摘要假定箔條所在位置處大氣運動速度是一個維納隨機過程，同時在忽略箔條的質量時箔條的運動完全反應當地大氣的運動，在此基礎上建立箔條雲團的擴散模型及數值模擬模型。Using a dissolved conservative material as a tracer in the water, a three - dimension advection - diffusion water exchange numerical model was used to study the flushing time by discharge and the discharge dominated region of the yangtze estuary. the flushing time of the yangtze estuary is an important eigenvalue, which denotes the water environmental capability of estuary
然後應用以溶解態的保守性物質做為研究長江口水體交換的載體，建立了完全三維對流擴散型的長江口水體交換的數值模型，對長江口的水體交換時間做了一個整體的計算。Using a dissolved conservative material as a tracer in the water, a three - dimension advection - diffusion water exchange numerical model was used to study the flushing time by discharge and the discharge dominated region of the yangtze estuary based on the successful simulation of flow field
在成功模擬長江口流場的基礎上，同時應用以溶解態的保守性物質做為長江口水體交換的載體，建立了三維對流擴散型的長江口水體交換的數值模型，對整個長江口的水體交換規律進行了研究。In this paper, river water quality prediction is integrated with water pollution control measures. two parameters, water environmental capacity and pollution index are selected for pollution control measures. the objective is achieved after the development of simulation model using one - dimensional advection dispersion equation. the model algorithm and computer program is an improvement over the existing water quality models, since the model solution involves four point implicit upwind schemes for water quality prediction and pollution control measures at each grid point. model simulation results the assessment of water environmental capacity that yield the acceptable and realistic pollutants concentration in order to maintain water quality objectives. the pollution and overall pollution index of the river is suggested for integrating number of contaminants variables into one index. study provides the mathematical and scientific procedure for water quality management. the new approach is helpful for the water pollution control and to study the impacts of waste effluents on the river system for strategic planning purposes
本文將水質預測及水污染控制措施有機地結合，選取水環境容量和污染指數作為水污染控制的參數.這樣，一維對流-擴散水質方程的求解除就是實現本研究目的的關鍵.本研究採用的模型在現有的水質模型基礎上有所改進，因為其採用四點隱格式對水質進行預測，推求可接納污染物的環境容量值及為保證水質而限定的污染物濃度值，從而制定相應的水污染控制措施.為整體考慮各種污染物的情況，建議採用河流的污染指數進而推求綜合污染指數.總之，本研究為水質保護提供了科學的計算方法，該法對水污染控制及污水對河道水質的影響是實用有效的Abstract : in this paper, river water quality prediction is integrated with water pollution control measures. two parameters, water environmental capacity and pollution index are selected for pollution control measures. the objective is achieved after the development of simulation model using one - dimensional advection dispersion equation. the model algorithm and computer program is an improvement over the existing water quality models, since the model solution involves four point implicit upwind schemes for water quality prediction and pollution control measures at each grid point. model simulation results the assessment of water environmental capacity that yield the acceptable and realistic pollutants concentration in order to maintain water quality objectives. the pollution and overall pollution index of the river is suggested for integrating number of contaminants variables into one index. study provides the mathematical and scientific procedure for water quality management. the new approach is helpful for the water pollution control and to study the impacts of waste effluents on the river system for strategic planning purposes
文摘:本文將水質預測及水污染控制措施有機地結合，選取水環境容量和污染指數作為水污染控制的參數.這樣，一維對流-擴散水質方程的求解除就是實現本研究目的的關鍵.本研究採用的模型在現有的水質模型基礎上有所改進，因為其採用四點隱格式對水質進行預測，推求可接納污染物的環境容量值及為保證水質而限定的污染物濃度值，從而制定相應的水污染控制措施.為整體考慮各種污染物的情況，建議採用河流的污染指數進而推求綜合污染指數.總之，本研究為水質保護提供了科學的計算方法，該法對水污染控制及污水對河道水質的影響是實用有效的Methods to extend the migration of endothelial cells on sprouts from four directions - moving up, down, left or right - in previous models to random direction in the present model, and develop a relevant 2d discrete model to simulate the process of tumor angiogenesis and compare the simulation results with some corresponding experimental data
方法將新生血管芽尖的內皮細胞遷移方向由先前模型的上、下、左、右四個方向擴展為任意方向，建立相應的二維離散模型，數值模擬實體腫瘤微脈管系統的生成過程，比較模擬結果與相關實驗數據的符合程度。By means of error analysis of recursion process of precise integration, it is found that the essential reason of obtaining the high precise numerical results of exponential matrix in the precise integration method is that the relative error of numerical computation is not enlarged in a whole recurrent process
通過對精細積分法遞推過程的誤差分析，發現該方法能獲得高精度數值結果的根本原因是：數值計算的相對誤差不隨遞推過程的進行而擴散。The propagation property of multiple - valued logical functions
多值邏輯函數的擴散性質The intrinsic chemical reaction rate constant was insensitive to the precursor and the calcinations history of cao, but the product layer diffusivity was affected by these two factors in the initial stage and decreased to a constant value with increasing conversion of cao
化學反應速率常數不受氧化鈣的先驅物與其鍛燒程序所影響，但產物層擴散系數在初始階段則受到上述兩因素的影響，並隨著氧化鈣的轉化而減少至一定值。At the initial stage of planar technique, b was employed as ideal diffusion impurity in base - region of npn si planar devices because of the match of its solid - solubility and diffusion coefficient in si with those of p in emission - region, and the good shield effect of sio2 film to b. but because of the relatively large solubility ( 5 1020 / cm3 at 1000 ) and the small diffusion coefficient, the linear slowly - changed distribution of acceptor b in pn junction can not be formed, which could not cater to the requirement of high - reversal - voltage devics. thereafter b - a1 paste - layer diffusion technology and close - tube ga - diffusion technology had been developed, while the former can lead to relatively large the base - region deviation and abruptly varied region in si, which caused severe decentralization of current amplification parameter, bad thermal stability and high tr ; the latter needed the relatively difficult pack technique, with poor repeatability, high rejection ratio, and poor diffusion quality and productio n efficiency
在平面工藝初期，由於b在硅中的固溶度、擴散系數與n型發射區的磷相匹配， sio _ 2對其又有良好的掩蔽作用，早被選為npn硅平面器件的理想基區擴散源，但b在硅中的固溶度大（ 1000時達到5 10 ~ （ 20 ） ，擴散系數小， b在硅中的雜質分佈不易形成pn結中雜質的線性緩變分佈，導致器件不能滿足高反壓的要求，隨之又出現了硼鋁塗層擴散工藝和閉管擴鎵工藝，前者會引起較大的基區偏差，雜質在硅內存在突變區域，導致放大系數分散嚴重，下降時間t _ f值較高，熱穩定性差；後者需要難度較大的真空封管技術，工藝重復性差，報廢率高，在擴散質量、生產效率諸方面均不能令人滿意。In chapter one, we propose a new mixed method called characteristics mixed finite element method for a convection - dominated diffusion problems with small parameter e : we handle the convection part whth backward difference scheme along the characteristics, obtain much smaller time - trunction errors and avoid numerical dispersion on the front of the peak curve of the flow : we use a lowest order mixed finite element method to deal with the diffusion part, so this scheme can approximate the unknow function and its following vector with high accuracy at the same time
第一章中我們對小參數對流占優擴散問題提出了新的數值方法? ?特徵混合有限元方法，即對方程的對流部分採用沿特徵線的後退差分格式求解，以保證較小的截斷誤差限並避免了在流動的鋒線前沿數值彌散現象的出現；對流動的擴散部分採用最低次混合元方法求解，以保證格式對未知函數及伴隨向量的同時高精度逼近。由於該方法中檢驗函數可取分片常數，此格式在某種意義上具有局部守恆性質。The characteristic approximation is used to handle the convection part along the direc - tion of fluid namely characteristic direction to ensure the high stability of the method in approximating the sharp fronts and reduce the numerical diffusion ; the mixed finite element spatial approximation is employed to deal with diffusion part and approximate the scalar unknown and the adjoint vector function optimally and simultaneously ; in order to preserve the integral conservation of the method, we introduce the modified characteristic method
該方法對方程的對流部分沿流體流動的方向即特徵方向離散以保證格式在流動的鋒線前沿逼近的高穩定性，消除數值彌散現象；對方程的擴散部分採用最低次混合有限元方法離散、同時以高精度逼近未知函數及未知函數的梯度；為保證方法的整體守恆性，在格式中引入修正項The new method is a combination of characteristic approximation to handle the convection part, to ensure the high stability of the method in approximating the sharp fronts and reduce the numerical diffusion, a smaller time truncation is gained at the same time, and a mixed finite element spatial approximation to deal with the diffusion part, the sealer unknown and the adjoint vector function are approximated optimally and simultaneously
此方法即為對方程的對流項沿流體流動的方向即特徵方向進行離散，從而保證格式在流動鋒線前沿逼近的高穩定性，消除了數值彌散現象，並得到了較小的時間截斷誤差；另一方面，對方程的擴散項採用混合元離散，可同時高精度逼近未知函數及其伴隨向量函數，理論分析表明，此方法是穩定的，具有最優的l ~ 2逼近精度。Numerical calculation results show that the developed scheme has many advantages such as having small dissipation and dispersion, needing little nodes, being put into practice easily, and being well suitable for both convection - dominant flow and diffusion - dominant flow
數值試驗結果表明，該格式具有數值耗散和數值頻散較小、節點少、便於應用等特點，且對求解對流擴散方程的對流占優和擴散占優的流動均有較好的適應性。分享友人