?approximation

approximation發(fā)音

[ə.prɔksi'meiʃən]

英：　　美：

approximation中文意思翻譯

n. 接近, 近似, 近似值

approximation詞形變化

副詞: approximatively | 形容詞: approximative |

approximation習慣用語(yǔ)

approximation特殊用法

approximation常見(jiàn)例句

1 、The interference terms are separated according to the antenna diagram approximation model.───依據天線(xiàn)圖解近似模型，干擾項可認為是獨立的。

2 、Is the Eikonal Approximation Certainly Bad at Larger Angles?───Eikonal近似在大角度一定不好嗎?

3 、That's two out of approximately a hundred.─── 除了他倆 那里大約還有一百人

4 、If a computer is used, a second approximation can be made with little trouble.───如果使用計算機，則可以毫不費事地計算第二次趨近。

5 、The remnant n(t)is the difference between the actual pilot output and the linear approximation to it.───剩余值n（t）是駕駛員的真實(shí)輸出和它的線(xiàn)性近似之差。

6 、A linear approximation of the non-linear GMSK is proposed to help GMSK to be readily accommodated into a SDR.───對非線(xiàn)性的GMSK分析了線(xiàn)性近似方法，這對于在軟件無(wú)線(xiàn)電中實(shí)現GMSK有重要意義。

7 、That's just an approximation, you understand.───你知道那僅僅是近似值。

8 、A sine wave shape is valid for many motors and it is a good approximation if the shape of the BEMF differs for a given motor.───其實(shí)，一般而言，很多的電動(dòng)機所產(chǎn)生的反電動(dòng)勢都是正弦波形狀的，而且即使不是正弦波形狀，也會(huì )比較接近正弦波的形式。

9 、Compared with the traditional Gaussian approximation method, the accuracy of mathod IS is observed.───與傳統的高斯近似法相比，更加準確、應用范圍更廣。

10 、In this class, we investigate the connection between networks for learning and the approximation scheme described so far.───在這堂課里，我們要認識到目前為止有關(guān)學(xué)習網(wǎng)路和近似值理論兩者前后關(guān)系的研究。

11 、When I sent for you, there were approximately 20 of them.─── 我派人去找你時(shí) 下面大概只有20個(gè)人

12 、Aapproximation of Fourier inverse integral using Fourier transform approximation for amplitude of harmonics in a finite Fourier series summation.───富氏級數中之諧波成份以富氏轉換近似并以有限級數和近似富氏逆轉換。

13 、It's the circle of life, or the approximation of it.─── 這是生命的循環(huán) 或者類(lèi)似的情況

14 、Those in whom the faculty of approximation to the beautiful exists in excess are poets, in the most universal sense of the word.───審美力最充沛的人，便是從最廣義來(lái)說(shuō)的詩(shī)人。

15 、The accuracy of function approximation and deducing are quite high and the learning speed is quite fast.───它可用來(lái)逼近任何連續函數,且逼近精度高,泛化能力強,學(xué)習速度快。

16 、The approximation of a linear dependency between heat flow and temperature difference leads to satisfactory results.───在熱流量與溫度差之間，近似地采用線(xiàn)性關(guān)系，也能得出令人滿(mǎn)意的結果。

17 、When it is solvable, the unique solution which is the optimal approximation to a given matrix is also given.───其次，給出了可解時(shí)解集合中與給定矩陣最佳逼近的解；

18 、The original of the Magnetocrystalline Anisotropy of Rare Earth in RCo_(5) have been studied by the single ion (molecular field) approximation.───利用單粒子點(diǎn)電荷模型研究了RCo5中一系列稀土離子 ,包括輕離子Pr3 + ,Nd3 + 和重離子Tb3 + ,Dy3 + ,Er3 + 的磁晶各向異性。

19 、The validity of the centralfield approximation rests on the great mass of the sun and on the relatively great separation of the planets.───中心場(chǎng)近似的準確性基于太陽(yáng)的巨大質(zhì)量以及行星之間的巨大距離。

20 、But the static dipole field is an oversimplified approximation without considering retarded potential.───但靜態(tài)磁偶極場(chǎng)假設過(guò)于簡(jiǎn)化，未考慮推遲勢效應。

21 、Approximately an hour before that, his car was blown up.─── 那之前一小時(shí)左右 他的車(chē)剛剛爆炸

22 、Togo receipts approximately 125 of them.─── 還有外賣(mài)發(fā)票 大約125張

23 、A rough approximation would be the dual spirals in pinwheel.───大致近似于紙風(fēng)車(chē)上的雙重螺旋線(xiàn)。

24 、In this form(3. 79)is used for practical approximation of the corrections for the topographic relief in the surroundings of the hole.───在這一形式下,式(3.79)可以使鉆孔周?chē)牡匦胃恼祵?shí)際上接近真值。

25 、To a good approximation, the induction response depends on the product of conducting layer thickness and conductivity.───為了更好地近似，感應現象取決于導電層的厚度和導電性。

26 、The approximation for MSE is obtained and used to solve the optimization problem for design variables.───作者在MSE極小的意義下，給出辨識設計變量的解析表達式。

27 、For any approximation to be valid it must provide a result that is in some sense close to the solution of the original problem.───任何有效的近似式必須在某種意義上提供一個(gè)接近于原問(wèn)題解的結果。

28 、Real-Time Sky-View Factor Calculation and Approximation.───實(shí)時(shí)天空因子的計算和近似。

29 、What he said was an approximation of my idea.───他說(shuō)的是很接近我的想法。

30 、Multi-point formula,depending on the segmented linear approximation,turns out to be effective in correcting the no...───多點(diǎn)法使用分段線(xiàn)性逼近的方法對非線(xiàn)性推移有良好的校正效果。

31 、Excellent agreement between the present approximation and the exact solution was found over the entire time domain.───在整個(gè)時(shí)間范圍內近似式運算結果和準確解均十分吻合。

32 、We treat the ionized impurity scattering rates within the single subband static screening approximation.───使用單子帶靜態(tài)屏蔽模型來(lái)處理電子與雜質(zhì)的散射過(guò)程。

33 、Semiclassical approximation has comprehensive applications in modern physics.───在現代物理學(xué)中，半經(jīng)典近似方法有著(zhù)廣泛的應用。

34 、The black-disk approximation used so far reproduces the coarse features, but not the finer details.───應用至今的黑圓盤(pán)近似值雖然再現了概貌，但不能再現更為詳細的細節。

35 、The demonstration of AT is thus simplified significantly and the error estimation of adiabatic approximation is expressed more explicitly.───其證明過(guò)程變得更簡(jiǎn)單,絕熱近似的誤差估計也被做得更直捷,并得到了(?)

36 、A closed-Form approximation of likelihood functions for discretely sampled diffusions: the exponent expansion.───7.離散采樣**的一個(gè)封閉式近似的或然性函數：指數的擴張。

37 、If we use the steady state approximation to treat this scheme, the equations derived are more complex .───如果我們對圖解用穩態(tài)近似法去處理，則推導出的方程比較復雜。

38 、Meanwhile both the mapping approximation ability and predication performance of the network are analyzed in details.───同時(shí)通過(guò)分析和實(shí)驗說(shuō)明網(wǎng)絡(luò )具有較強的映射能力和預測性能。

39 、Mmhmm, my approximation with the help of the airline.─── 恩 我的估算加上航空公司的幫助

40 、Wallis has developed a simplified analysis incorporating the same approximation.───威利斯曾結合同樣的假設，做出了一個(gè)簡(jiǎn)化的分析。

41 、In soft-photon approximation, the average excitation energy only appears in the first and second order terms of field frequency.───在軟光子近似下，平均激發(fā)能僅出現在光場(chǎng)頻率的一階和二階項上。

42 、The He 2+ +H Impact Ionization process is investigated using a continuum distorted wave method with the eikonal initial_state(CDW_EIS) approximation.───利用初態(tài)程函近似的連續扭曲波方法研究了He2+離子與H原子的碰撞電離過(guò)程.

43 、The calculation method for the vibrational partition sums Qvib used is the harmonic oscillator approximation.───其中,轉動(dòng)配分函數考慮了離心扭曲修正,振動(dòng)配分函數采用諧振子近似。

44 、This is approximately ten miles out from the forest.─── 這里離森林大約有10英里

45 、Based on individual similarities, an approximation strategy of similar fitness is put forward to reduce user fatigue.───為減輕用戶(hù)疲勞，基于個(gè)體相似度，提出一種類(lèi)適應度近似策略。

46 、Theorem 3.3 Algorithm 2 is a polynomial approximation algorithm of using at most 2k-1 matchings.───定理3.3 算法2是最多用2k-1次匹配的多項式近似算法。

47 、The CPU time of the Hermite-Galerkin approximation is greatly less than that of the finite difference method.───對Navier-Stokes方程構造的Hermit-Galerkin近似 與有限差分近似相比，Hermite--alerkin近似數值分析的時(shí)間減少了許多。

48 、Finite sum of harmonics for approximation of a step exponential pulse.───以有限諧波級數近似單邊遞減波。

49 、To a very good approximation the total energy is conserved.───作為一個(gè)非常好的近似，這里的總能量是守恒的。

50 、It's derivation involved no approximation.───它的推導過(guò)程不含近似處理。

51 、Once more a very good source of information about connections between different approximation techniques.───再一次推薦，這是一篇解釋不同估計法彼此間關(guān)聯(lián)的優(yōu)良資訊來(lái)源。

52 、The HEWC problem was formulated as an integer linear program, and an approximation solution was obtained by using LP-relation and rounding heuristic.───HEWC問(wèn)題第一次被歸結為一個(gè)整數線(xiàn)性規劃問(wèn)題，并且利用LP的放松問(wèn)題和有界啟發(fā)得到一個(gè)近似解。

53 、One is solving the QPSK NDA maximum likelihood equation by gradient approximation, which has better convergence performance than other methods.───一種是基于NDA(Non-Data-Aided)最大似然估計的梯度迭代求解方法,這種方法與其它迭代方法相比,具有更好的收斂性能。

54 、Musgrave, G.W., 1947, The quantitative evaluation of factors in water erosion： A first approximation.───萬(wàn)鑫森、陳清茂1980覆蓋及敷蓋對坡地土壤結核量之影響。

55 、Under rotating wave approximation, the total coherent Hamiltonian of photon-phonon coupling system driven by incident field is introduced.───在旋轉波近似下，得到在入射光驅動(dòng)下光子－聲子耦合體系的總的相干性哈密頓算符。

56 、Info:This is a beautiful Cocktail/Debs/Prom dress it is made to order, so delivery time would be approxim ......───主要材質(zhì):其它次要材質(zhì):其它尺碼:全碼適用季節:夏

57 、Similarly, high heat flows are to be expected among the active or not-too-long extinct magmatic belts of plate approximation zones.───同樣，在板塊相互靠近的地帶的活動(dòng)巖漿帶或熄滅不久的巖漿帶中也可以出現高熱流。

58 、Maybe we found approximately where it is.─── 也許我們找到了大致的藏寶地

59 、He could travel with an approximation of ease if not enjoyment in the class that disconcerted him.───他與同他步調不一致的人外出時(shí)，即使感到不快也能做到近乎坦蕩。

60 、And by a monotone integral operator, we give an asymptotic approximation way which is further improving the older ways.───并且使用一個(gè)具有單調性的算子，給出了一種更實(shí)用更有效的對破產(chǎn)時(shí)刻赤字分布函數漸進(jìn)估計的方法。

61 、Baldwin B S,Lomax H.Thin Layer Approximation and Algebraic Model for Seperated Turbulent Flows[R].AIAA 78-257.───周力行.湍流氣粒兩相流動(dòng)和燃燒的理論與數值模擬[M].北京:科學(xué)出版社,1994.

62 、She met him out at a bar, and I have an approximate date.─── 她在某個(gè)酒吧遇見(jiàn)的他 我現在又有個(gè)合適的約會(huì )對象

63 、What they need is an approximation or even a semblance of normalcy.───他們需要的是盡量保持正常甚至是看上去正常。

64 、The radiance of jet plume in arbitrary light of sight are predicated using Curtis-Godson micro-spectrum approximation.───利用微觀(guān)譜帶Curtis-Godson單線(xiàn)近似方法,計算了沿任一視線(xiàn)飛機尾焰的紅外輻射亮度。

65 、One can increase approximation of M-band multiscaling functions with help of MST.───對M帶多尺度函數的逼近階的提升,需要引入M帶尺度相似變換(MST)。

66 、Even though an approximation of this overhead is subtracted, it still has subtle timing effects on multithreaded applications.───即使減去此系統開(kāi)銷(xiāo)的近似值,它仍然對多線(xiàn)程應用程序有細微計時(shí)影響。

67 、In 1981 the 30 year bond which is a good approximation for mortgage rates, was yielding 14% today it yields 4%.───在1981年的30年期國債是一個(gè)很好的近似抵押貸款利率，收益率為14%，現在則收益率4%。

68 、The leading-term approximation formulus is used to calculate the Sommerfeld integrals in the far-field region.───對于遠場(chǎng)區的索末菲積分，利用遠場(chǎng)首項近似公式對其進(jìn)行計算。

69 、WITHOUT TESTING THEY CANNOT BE ACCURATLY SET.THEY ARE THERE AS A GUIDE TO GIVE A ROUGH APPROXIMATION OF THE SKILL.───只有通過(guò)測試才能設置合理。這些技能的粗略的近似值只是一些指引而已。

70 、From the Hamiltonian of the atomic system,making use of Born-Markoff approximation,the optical Bloch equations are derived.───從系統的哈密頓量出發(fā),利用玻恩馬爾可夫近似,推導出了原子的光學(xué)布洛赫方程。

71 、Subtracting this value from 100 can give a good approximation of total CPU usage.───從100里面減去這個(gè)值可以得到一個(gè)總的CPU使用量的優(yōu)良的近似值。

72 、The second Born approximation obtains better results compared with the experimental data.───和實(shí)驗相比較,第二玻恩近似方法給出了較好的結果;

73 、A low-power DDFS based on eight segmented linear approximation is implemented, and this design achieves 60 dBc of SFDR.───實(shí)現了一個(gè)基于八分段線(xiàn)性近似的低功耗DDFS，該結構獲得了60dB的SFDR。

74 、It is far from being in all circumstances a good approximation to the central concept.───它決不是在任何情況下一個(gè)很接近于中心觀(guān)念的定義。

75 、Single-precision numbers store an approximation of a real number.───單精度數值存儲實(shí)數數值的近似值。

76 、As an approximation he should understand enough computer programming.───他大體上要弄懂足夠的計算機程序編制。

77 、The multilevel B-splines approximation is a good method for surface reconstruction.───多層B樣條方法在曲面的擬合中提供了新的途徑。

78 、Recently, wavelet neural networks have become apopular tool for non-linear functional approximation.───小波神經(jīng)網(wǎng)絡(luò )是近年來(lái)發(fā)展起來(lái)的一種逼近非線(xiàn)性函數的新型人工神經(jīng)網(wǎng)絡(luò )。

79 、Use of higher roots of (8. 88) in (8. 85) gives approximation to excited state wave function.───將(8.88)中的高值根用于(8.85),給出激發(fā)態(tài)波函數的近似。

80 、A satisfactory approximation to monochromatic light can be obtained with a filter placed in front of the arc.───在碳弧前面放一個(gè)濾光片就可以得到令人滿(mǎn)意的近單色光。

81 、Do you need physical accuracy or is an approximation ok?───你是一個(gè)需要體力的準確性或近似嗎?

82 、Finite sum of harmonics for approximation of a source of step exponential pulse.───以有限諧波級數近似單邊遞減波電源。

83 、The Wisconsin experiment proved one could cobble together a fair approximation of a prairie.───威斯康星的實(shí)驗證明，可以隨意直接拼湊出一片近似的草原。

84 、The jellium model in a certain approximation leads to the equation .───凝膠模型在某種近似下導致下列方程。

85 、Thus Planck's law can be used as a good approximation.───因而布朗克定律可以作為一個(gè)較好的近似計算。

86 、A Novel Distributed Approximation Algorithm for Minimum Connected Dominating Set.───一個(gè)新的分布式最小連通支配集近似算法。

87 、Variational method and TDA approximation was applied to construct the SD pairs in the SD-pair shell model (SDPSM).───在SD對殼模型的理論框架下,利用變分法及TDA近似確定SD對結構。

88 、There are two ways to perform successive approximation: using hardware and using software mixed with hardware.───實(shí)現逐次逼近的辦法有兩種：使用硬件以及軟、硬件混合使用。

89 、The key is that this above ground stock of gold grows by about 1.75% per annum, which is approximately equal to new world population growth and is approximately equal to new wealth creation.─── 關(guān)鍵在于已開(kāi)采的黃金存量 年增長(cháng)率約為1.75% 大致相當于世界人口增長(cháng)率 也大致相當于新財富的創(chuàng )造速率

90 、And it is noted that the precision of the adiabatic approximation is mainly dependent on the coupling constant.───并且指出了絕熱近似的好壞主要由耦合常數的大小決定。

高中四個(gè)常用帕德近似式

高中四個(gè)常用帕德近似式介紹如下：

1.對數函數的帕德近似：$\ln(1+x) \approx \frac{x}{1-x}, |x|<1$。2. 指數函數的帕德近似：$e^x \approx \frac{1+1.494x+0.276x^2}{1-0.406x+0.079x^2}, |x|<0.5$。

3. 正切函數的帕德近似：$ an(x) \approx x+\frac{1}{3}x^3+\frac{2}{15}x^5, |x|<\frac{\pi}{4}$。4. 反正弦函數的帕德近似：$\sin(x) \approx x-\frac{1}{6}x^3+\frac{1}{120}x^5, |x|<\frac{\pi}{2}$。

帕德近似(Pade approximation)是有理函數逼近的一種方法。帕德近似就是是法國數學(xué)家亨利·帕德發(fā)明的有理多項式近似法。帕德近似往往比截斷的泰勒級數準確，而且當泰勒級數不收斂時(shí)，帕德近似往往仍可行，所以多用于在計算機數學(xué)中。

應用

自然界中多種媒質(zhì)屬于色散媒質(zhì)；它們的色散特性也不盡相同，尚未發(fā)現統一的規律迄今，已提出幾種經(jīng)驗模型描述這些特性，其中較著(zhù)名的有：用于人體組織、土壤等媒質(zhì)的 Debye 模型用于等離子體、金屬等媒質(zhì)的 Drude 模型；

用于光學(xué)材料的 Lorentz 模型；用于生物組織、高分子材料等媒質(zhì)的 Cole- Cole(C- C)模型；用于甘油、丙二醇等媒質(zhì)的 Davidson- Cole(D- C)模型；用于聚合物的 Havril-iak- Negami(H- N)模型。

為了引入媒質(zhì)的色散特性，近幾年來(lái)，時(shí)域有限差分(Finite- Difference Time- Domain， FDTD)法的建模對象已從常規媒質(zhì)拓展到色散媒質(zhì)。針對前述的第一大類(lèi)媒質(zhì)，已提出好幾種 FDTD 方案，主要思路有:

引入輔助微分方程(Auxiliary Differential Equation， ADE) 、利用遞歸卷積(RecursiveConvolution，RC)、定義移位算子(ShiftOperator，SO) 等。然而，分數階導數仍是 FDTD 建模第二大類(lèi)媒質(zhì)面臨的主要困難為此，Rekanos 等人利用帕德(Padé)近似法。

本文提出了一種 ADE- FDTD- CPML 統一實(shí)現方案，該方案具有適用范圍廣、實(shí)現復雜度低等優(yōu)勢，可用于統一處理射頻、微波、紅外和毫米波等工程中一般電色散媒質(zhì)的電磁問(wèn)題，媒質(zhì)可以是一維或多維的、單極或多極的、無(wú)耗或有耗的。幾個(gè)算例的初步結果顯示:在超寬帶頻譜范圍，該方案具有較高的數值精度。今后，該方案有望進(jìn)一步**到磁色散媒質(zhì)。 

酶能催化化學(xué)反應的機理是什么

在任何化學(xué)反應中，反應物分子必須超過(guò)一定的能閾，成為活化的狀態(tài)，才能發(fā)生變化，形成產(chǎn)物。這種提高低能分子達到活化狀態(tài)的能量，稱(chēng)為活化能。催化劑的作用，主要是降低反應所需的活化能，以致相同的能量能使更多的分子活化，從而加速反應的進(jìn)行。

酶能顯著(zhù)地降低活化能，故能表現為高度的催化效率。例如前述的H2O2酶的例子，可以顯著(zhù)地看出，酶能降低反應活化能，使反應速度增高千百萬(wàn)倍以上。

酶作用機理

1.趨近效應（approximation）和定向效應（oientation） 酶可以將它的底物結合在它的活性部位由于化學(xué)反應速度與反應物濃度成正比，若在反應系統的某一局部區域，底物濃度增高，則反應速度也隨之提高，此外，酶與底物間的靠近具有一定的取向，這樣反應物分子才被作用，大大增加了ES復合物進(jìn)入活化狀態(tài)的機率。

2.張力作用（distortionorstrain）

底物的結合可誘導酶分子構象發(fā)生變化，比底物大得多的酶分子的三、四級結構的變化，也可對底物產(chǎn)生張力作用，使底物扭曲，促進(jìn)ES進(jìn)入活性狀態(tài)。

3.酸堿催化作用（acid-basecatalysis）

酶的活性中心具有某些氨基酸殘基的R基團，這些基團往往是良好的質(zhì)子供體或受體，在水溶液中這些廣義的酸性基團或廣義的堿性基團對許多化學(xué)反應是有力的催化劑。

4.共價(jià)催化作用（covalentcatalysis）

某些酶能與底物形成極不穩定的、共價(jià)結合的ES復合物，這些復合物比無(wú)酶存在時(shí)更容易進(jìn)行化學(xué)反應。

例如：無(wú)酶催化的反應　RX+H2O→ROH+Hx慢

有酶存在時(shí)　RX+E桹H→ROH+EX快

EX+H2O→E桹H+HX快?