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tetrahedron

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tetrahedron n.(pl. tetrahedrons, -dra )1...

n. (pl. tetrahedrons, -dra ) 1.【幾】四面體。 2.【植物；植物學】四分體形。 adj. -dral “basalt tetrahedron“ 中文翻譯：   玄武巖四面體“concentration tetrahedron“ 中文翻譯：   濃度四面體“concrete tetrahedron“ 中文翻譯：   混凝土四面體“coordinate tetrahedron“ 中文翻譯：   坐標四面形, 坐標四面體“coordination tetrahedron“ 中文翻譯：   配位四面體“elementary tetrahedron“ 中文翻譯：   元四面體“fire tetrahedron“ 中文翻譯：   燃燒四面體“fundamental tetrahedron“ 中文翻譯：   基本四面體“local tetrahedron“ 中文翻譯：   局部四面體“negative tetrahedron“ 中文翻譯：   負四面體“orthocentric tetrahedron“ 中文翻譯：   垂心四面體“orthorhombic tetrahedron“ 中文翻譯：   菱方四面體“overlapping tetrahedron“ 中文翻譯：   重迭四面體“polar tetrahedron“ 中文翻譯：   配極四面體“pollen tetrahedron“ 中文翻譯：   花粉四面體; 四角錐形花粉“positive tetrahedron“ 中文翻譯：   正四面體“principal tetrahedron“ 中文翻譯：   主四面體“pyramidal tetrahedron“ 中文翻譯：   棱錐四面體; 三角三四面體; 錐形四面體“regular tetrahedron“ 中文翻譯：   正四面體“rhombic tetrahedron“ 中文翻譯：   菱方四面體“silica tetrahedron“ 中文翻譯：   硅氧四面體“supplementary tetrahedron“ 中文翻譯：   補充四面體“taste tetrahedron“ 中文翻譯：   味覺四面體“tetragonal tetrahedron“ 中文翻譯：   四方四面體“tetrahedron block“ 中文翻譯：   四面體塊體“tetrahedroid pebble“ 中文翻譯：   近四面體卵石

tetrahydrocannabinol

In structure ( 6 ) mn ( 1 ) 2 + links with two [ mo6p4 ] units by sharing corners and then forms mn ( 1 ) [ mo6p4 ] 2 , while mn ( 2 ) links to four different mn ( l ) [ mo6p4 ] 2 clusters and forms plenary channel structure . polyanion [ p2mo5o23 ] of compounds ( 9 ) and ( 10 ) consists of five mooe octahedra which form a ring by sharing corners and edges , and two po4 tetrahedra which exist in two sides of the ring plane by three oxygen atoms bonded to the mo - o cluster 化合物( 9 )和( 10 )的多陰離子[ p _ 2mo _ 5o _ ( 23 ) ]由五個moo _ 6八面體通過共邊和共角連接形成一個環，每個moo _ 6八面體均帶有2個端基氧，在其環平面的上下兩側各有一組po _ 4四面體通過共用3個氧原子與mo - o簇鍵合。

Considering characteristic of different material zones of dam foundation in computation model , the compatible displacement method for incompatible mesh is presented in this paper , it is convenient for considering the interaction between the arch dam body and the dam abutment . therefore , the mesh of dam body can be generated with 3d hexahedron elements but that of dam foundation is generated with 3d tetrahedron elements 針對計算模型中壩基材料復雜、地質構造豐富的特點，提出了“典型面控制法”和壩基用空間四面體單元離散，壩體(包括附近區域)用空間六面體單元離散的非一致網格協調位移解法。

The simulation methods and content about the mesh generation , the boundary condition of rotating wheels and moving ground of single car , and about the steady study on the two car running in row and overtaking process has shown the calculation results reliability and the numerical simulation methods feasibility . based on the comparison and analysis of mesh strategy , the descartes mesh strategy and the tetrahedron + prism mesh strategy are chosen . the continuous unsteady overtaking process of the vehicles , traveling with constant but unequal speed is replaced by a finite numerber of steps ; in each the relative position of both vehicles changes 最后利用滑動交接面技術和動網格技術進行了瞬態的轎車超過某國產大型運輸車的數值模擬研究,在此之前國內外對此項技術均未有系統的研究和可借鑒的結論,以側向間距0 . 5倍轎車車寬為典型,用定性和定量兩種方法對比分析了超車過程中的轎車和運輸車與其單車情況及前文穩態模擬的異同,并將六種側向間距的瞬態結果與單車情況和穩態模擬結果進行了對比分析。

( 4 ) this program was developed on the base of the zrcae software , comparing with the process of calculation with tetrahedron element , only one additional choice operation was needed if the user want using hexahedron element . so the characteristic for simple operation of the zrcae software was kept Gu ）本程序是在商品化的紫瑞cae基礎上開發的，與采用四面體單元進行計算相比，用戶要采用六面體單元進行計算，只需增加一跟擇操作，所以本程序保持了紫瑞cae操作簡單的特點。

Product this getting wet pouch active mt of packaging completely , main raw materials active mt one natural having special crystallization layers of silicate clay ore of form scarce , sublimated and processed and succeeded by special technology , one layer of forms tetrahedron and octahedra chip of it are arranged into six mao net , cause the crystalline grain to expand after absorbing water , pick up the moisture , get rid of oxygen , keeps fresh , anticorro sion , long result function , it is a kind of healthy green environmentally safe product 本品是透濕性小袋包裝的活性mt ，主要原料活性mt是一種天然稀有的具特殊結晶層狀的硅酸鹽粘土礦，經特殊技術提純加工而成，它的層狀四面體和八面體晶片排成六角網格，吸水后引起晶格膨脹，具吸濕除氧保鮮防蝕長效功能，是一種健康綠色環保產品。

The temperature from amorphous to crystal of tungsten oxide sol - gel films with catalyst is increased and the reason is in studying . as results of tunnel scan - afm , both pt sputtered tungsten oxide films and pt sputtered tungsten oxide sol - gel films there is distinct and out - of - order parallel line structure on the surface of amorphous . molecules of the sample tend to tetrahedron and the former has more planarer structure 隧道-原子力顯微鏡測試結果表明:非晶態時,磁控濺射摻鉑薄膜樣品表面和溶膠凝膠摻鉑樣品表面都有明顯的平行線狀結構,長程無序,分子趨于四面體結構,只是前者比后者表面較平整;晶態時,磁控摻鉑樣品在自然生長面上原子呈平面分布,長程有序,溶膠摻鉑樣品則呈wo6面心結構。

By making some assumptions , collision frequency were presented . then the the flocculation kinetics model was established through population balance equation . comparison of experimental data and modeling results indicate that there are the same trend between the two . so the model can predict floes number and size during flocculation of yellow river ' s loess particles without using empirical parameters . the tem and sem were used to obsever floes in the study of floe structure . the flocculation was divided as flocculi , floc and floe aggregate . the floes structure model was established by assumption that particles position in floe accords with tetrahedron . the fractal dimension of model and experimental floes was found to be coincidentso the model can reflect the structure of flocs formed in flocculation of yellow river ' s loess particles by macromolecule flocculant at a certain extent 最后，本文還對絮凝動力學和絮體結構進行了研究，在前人研究的基礎上，針對高分子絮凝黃河泥沙，對絮凝過程作了一些符合試驗條件的假設，建立了顆粒碰撞頻率表達式，應用了顆粒數量平衡方程，從而建立了絮凝過程的動力學生長模型，模型計算結果與試驗數據對比表明，二者趨勢一致，在沒有使用經驗參數的情況下基本上能夠描述黃河泥沙絮凝過程中絮體數量和尺寸分布的變化過程；對絮體結構的研究中，應用掃描電子顯微鏡和透射電子顯微鏡對絮體進行了觀察，將絮體分為絮粒、絮團和絮網三個不同的生長階段，通過假設顆粒結合位置符西安建筑科技大學博士學位論文合正四面體，建立了絮體結構模型，計算得到的模型絮體分形維數基本與試驗中的實際絮體相符，在一定程度上能夠反映高分子絮凝黃河泥沙生成的絮體結構。

As a result 4 the rising annealing temperature induces si02 phase to form , also ivolves the formation of a si phase . in high - temperature - annealed sio ~ , films the excess silicon atoms are present as si - si4 tetrahedra , randomly dispersed in the amorphous si02 matrix . photoluminescent spectra were observed for the samples excided by the laser whose wavelength is 365nm . the pl peak is located at about 445nm , which dose n ' t shift as the annealing temperature changes . as the annealing temperature is raised , the luminescent intensity increases . the phenomena suggest that the si - o - si bond as a defect center which is broken down by the stress at the si nc / si02 interface is the primary source of blue luminescence 這個陡的界面由于明顯的晶格結構的差別而有較大的應力。界面的形成伴隨著界面發光中心的增加，同時pl強度在l戶800有一個大的增強。這個結果提示我們，界面上h 0 s工鍵斷裂形成的nbohc應是藍光發射的主要原因。

Product this getting wet pouch active mt of packaging completely , main raw materials active mt one natural having special crystallization layers of silicate clay ore of form scarce , sublimated and processed and succeeded by special technology , one layer of forms tetrahedron and octahedra chip of it are arranged into six mao net , cause the crystalline grain to expand after absorbing water , pick up the moisture , get rid of oxygen , keeps fresh , anticorro sion , long result function , it is a kind of healthy green environmentally safe product 本品是透濕性小袋包裝的活性mt ，主要原料活性mt是一種天然稀有的具特殊結晶層狀的硅酸鹽粘土礦，經特殊技術提純加工而成，它的層狀四面體和八面體晶片排成六角網格，吸水后引起晶格膨脹，具吸濕、除氧、保鮮、防蝕、長效功能，是一種健康綠色環保產品。

Marching cubes ( mc ) algorithm and marching tetrahedra ( mt ) algorithm are introduced . this dissertation chooses mt algorithm to extract zero isosurface in order to avoid ambiguity of mc algorithm . in accordance with the intersection feature between isosurface and voxel , this dissertation improves mt algorithm and proposes nine configurations of distance function values of tetrahedron vertices 分析marchingcubes ( mc )算法的二義性，選擇marchingtetrahedra ( mt )算法進行“ 0 ”等值面的抽取；并根據等值面與體素相交的特點，對mt算法進行改進，提出四面體的頂點9種分布情況。

The flux across each cell face is calculated using a flux - vector splitting technique . higher - order scheme is obtained by expanding the cell - centered solution to each cell face using a linear reconstruction formula based on geometrical invariant features of triangles and tetrahedra , which reduces computer memory requirements 采用了基于網格單元幾何特性的線性重建( reconstruction )公式并引入通量矢量分裂( flux - vectorsplitting )技術，計算得到控制體邊界上二階精度的通量值。

The main contributions of the dissertation are as follow : ( 1 ) the possibility of generation hexahedron mesh through tetrahedron conversion method was studied , and a set of feasible method to deal with the boundary condition of constraint and loads has been brought forward 本文的主要工作包括如下幾個方面： ( 1 )研究了在紫瑞cae基礎上采用四面體轉換法進行六面體網格全自動剖分的可行性并對約束和載荷的處理提出了一套可行的方案。

It was later demonstrated the possibility to get hexahedron mesh through tetrahedron conversion method . basing on the preprocessor module of zrcae software , a program system has been developed with which hexahedron mesh can be automatically generated 隨后論證了四面體轉換法全自動生成六面體網格的可行性，并在紫瑞cae軟件前處理模塊的基礎上，研制開發了八節點和二十節點六面體網格的全自動剖分程序。

These conclusions are expounded on the basis of the peculiarity of cube and regular tetrahedron of dna sequences , so they are rationalization , and they will be very useful in the study of the classification and the evolution of organisms 它們都是根據dna序列的立方體和正四面體的性質而提出來的，有一定的合理性。本文的結論對人們研究生物體的分類和進化有著很重要的作用。

Based on the results of present investigation , by theoretic analysis and physical model experimentation and numerical experimentation , the deeper research for flow deceleration through frames made of hollow tetrahedrons is carried out 本文在現有研究成果的基礎上，通過理論分析、物模試驗、數值實驗等研究手段對空心四面體框架群的減速特性進行了較為深入的研究。

Plato conjectured each of these elements to be made up of a certain platonic solid : the element of earth would be a cube , of air an octahedron , of water an icosahedron , and of fire a tetrahedron 柏拉圖推測每一種元素都是由某些理想立方體組成：地元素是由立方體組成，風元素是一個八面體，水元素是二十面體，火元素是四面體。

Consisted of two twisted layers n - gons . theory 2 implies the sufficient and necessary conditions of c . c . consisted of nested tetrahedrons . theory 3 implies the sufficient and necessary conditions of c . c 在1995年， r . moechel和c . simo發現了：在中，由兩層大小可以不等，方向相同的正多邊形構成中心構型的充要條件。

Using the visual program language - visual basic6 . 0 ( vb ) , i compiled the procedures of tetrahedron and simplex , and realized the automation of mobilex phase optimization 利用可視化的編程語言visualbasic6 . 0 (簡稱vb ) ，編寫四面體法和單純形法的計算機優化軟件，實現了流動相優化的自動化。

The tetrahedron method is proposed by yu - qing sun and his graduate student , which is used to optimize the strength and selectivity of mobile phase in the condition of isocratic elution 四面體法是孫毓慶等在glajch三角形優化法的基礎上提出的，優化流動相強度和選擇性的方法。