行星演化學 的英文怎麼說
中文拼音 [hángxīngyǎnhuàxué]
行星演化學
英文
planetary cosmogony- 行 : 行Ⅰ名詞1 (行列) line; row 2 (排行) seniority among brothers and sisters:你行幾? 我行三。where...
- 星 : 名詞1 (夜晚天空中閃爍發光的天體) star 2 [天文學] (宇宙間能發射光或反射光的天體) heavenly body...
- 演 : 動詞1 (演變; 演化) develop; evolve 2 (發揮) deduce; elaborate 3 (依照程式練習或計算) drill;...
- 學 : Ⅰ動詞1 (學習) study; learn 2 (模仿) imitate; mimic Ⅱ名詞1 (學問) learning; knowledge 2 (學...
- 行星 : [天文學] planet
-
The extreme carbon stars, whose derived mass loss rates and optical depths are both very high, are more evolved than infrared carbon stars. these stars are expected to evolve into protoplanatary nebula soon
極端碳星是高度演化后的紅外碳星,它的質量損失率及光深都非常高,幾乎沒有其光學對應體,並將很快演化為前行星狀星雲。Given the initial conditions including ( 1 ) number density distribution in space which has the similar form to the present day ones, ( 2 ) both the power law and gaussian mass functions for clusters, and ( 3 ) two different velocity distributions which one has a constant dispersion and the other is described by the eddington formula, the dynamical evolution of globular clusters in our milky way galaxy is investigated in detail by means of monte carlo simulations
本文採用與觀測結果具有相同形式的球狀星團空間密度分佈函數,在給定兩種球狀星團系統的初始質量譜(冪律的和對數高斯的)和兩種球狀星團系統的初始速度分佈函數(愛丁頓速度分佈函數和常數的速度彌散度)條件下,我們採用montecarlo的方法對球狀星團系統的動力學演化進行討論。Evolution of stars of all masses takes place on a hydrodynamic time scale.
各種質量的恆星的演化,均以流體力學的時間尺度進行。Many planets ( for example, ganymede, mercury, the earth, jupiter and saturn ) and stars ( for example, the sun ) possess intrinsic magnetic fields. the explanation for their existence and variation remains a great challenge to planetary scientists and astrophysicists. this article attempts to review some recent developments and difficulties in the study of magnetohydrodynamics for the electrically conducting fluid interiors of planets and stars. it is the fluid motions, usually driven by thermal convection, that generate and sustain magnetic fields through magnetohydrodynamic processes in planets and stars. in planets, the magnetohydrodynamic processes are strongly affected by the combined and inseparable effects of rotation, magnetic fields and spherical geometry. the key dynamics involves the interaction between the coriolis and lorentz forces. in the sun, it is the solar tachocline, a thin shear flow layer located at the base of the convection envelope, that plays an essential role in the solar magnetohydrodynamic processes which produce the 11 - year sunspot cycle. some results of a new nonlinear three - dimensional solar dynamo model are also presented
許多行星(如木衛三,水星,地球,木星和土星)和恆星(如太陽)具有內部磁場.對這些磁場的存在和變化的解釋對行星科學家和天體物理學家是一個巨大的挑戰.本文試圖總結行星和恆星的導電流體內部磁流體力學研究的新近發展和困難.一般由熱對流驅動的流動通過磁流體力學過程產生並維持在行星和恆星中的磁場.在行星中磁流體力學過程強烈地受到轉動,磁場和球幾何位型的綜合影響.其動力學的關鍵方面涉及科里奧利力和洛倫茲力間的相互作用.在太陽中其流線,即處于對流層的薄的剪切流層在太陽的磁流體力學過程中扮演了一個基本的角色,並由之產生了11年的太陽黑子周期.本文也給出了一個新的非線性三維太陽發電機模型" this questions our understanding of how giant planets are formed and evolve, " said robert noyes, a senior physicist at the harvard - smithsonian center for astrophysics ( cfa )
"這向我們對于大行星是如何行成演化的理解提出了置疑. "羅伯特?諾伊斯說.他是哈佛-史密森納天體物理中心的一名資深物理學家The asteroids are the most important small bodies in the solarsystem, and they mainly lies in the two locations - a main belt between the mars ' s orbit and the jupiter ' s and the near - earth space. the most feature of the orbits of near - earth asteroids ( neas ) is that the semi - major axes of the orbits are nearly equal to that of the earth or the perihelia distances are approximate to or even less than the mean distance between the sun and the earth, thus they could move into inside of the earth ' s orbit, so that they might close approach or even colliside with the earth ( or other planets, such as the venus, the mars, etc. ). the characteristic brings about some difficulties in the numerical research during their orbital evolution, which leads to the failure of the normalization technique in the general removal impact singularities of celestial mechanics methods and the symplectic algorithm which is successfully applied to the investigation in quality. by comparing the computation effects of several common numerical methods ( including symplectic algorithm ), and considering the nature of the movement of the small bodies, the corresponding treatments are provided here to improve the reliability of the computation
小行星是太陽系最重要的一類小天體,主要分佈在兩個區域;火星和木星軌道之間的一條主帶和近地空間.近地小行星軌道的最大特點是其軌道半長徑與地球軌道半長徑相近,或近日距離接近甚至小於日地平均距離,其運動可深入到地球軌道的內部,這將導致該類小行星與地球(還有金星、火星等)十分靠近甚至發生碰撞.這一特徵給其軌道演化數值研究帶來一些困難,包括天體力學方法中一般消除碰撞奇點的正規化處理以及對定性研究十分成功的辛演算法都將在不同程度上失效.通過對幾種常用數值方法(包括辛演算法)計算效果的比較,根據小天體運動自身的特性,給出了相應處理措施,從而可提高計算結果的可靠性Topics include : planets, planet formation ; stars, the sun, " normal " stars, star formation ; stellar evolution, supernovae, compact objects ( white dwarfs, neutron stars, and black holes ), plusars, binary x - ray sources ; star clusters, globular and open clusters ; interstellar medium, gas, dust, magnetic fields, cosmic rays ; distance ladder ; galaxies, normal and active galaxies, jets ; gravitational lensing ; large scaling structure ; newtonian cosmology, dynamical expansion and thermal history of the universe ; cosmic microwave background radiation ; big - bang nucleosynthesis
課程的主題包含了:行星、行星形成;恆星、太陽、正常的恆星、恆星形成;恆星演化、超新星、緻密天體(白矮星、中子星及黑洞) 、波霎、雙x -射線源;星團、球狀及疏散星團;星際介質、氣體、塵埃、磁場、宇宙射線;距離階梯;星系、正常及活躍星系、噴流;重力透鏡;大尺度結構;牛頓宇宙學、宇宙的動力膨脹及溫度發展歷史;宇宙背景微波輻射;大霹靂核合成。We might therefore retrace the tectono - magmatic evolutionary history of orogenic belts in the light of characteristics of volcanic magmatism at different forming and evolutionary stages of orogenic belts and further explore some important scientific problems of global dynamics and comparative planetary dynamics by means of comparison on larger scales
因此,可以根據造山帶形成、演化不同階段火山巖漿作用的特點來重溯造山帶的構造巖漿演化歷史,進而從更大尺度上加以對比,探索全球動力學乃至比較行星動力學等重大科學問題。We might retrace the history of tectono - magmatic evolution of volcanic magmatism at different stages of formation - evolution of orogenic belts and further explore some important scientific problems of global dynamics and comparative planetary dynamics by means of comparison in larger scales
因此,我們可以根據造山帶形成演化不同階段火山巖漿作用的特點來重溯造山帶的構造-巖漿演化歷史,並進而從更大尺度上加以對比,探索全球動力學乃至比較行星動力學等重大科學問題。Optimization of system and mission based on genetic algorithm ( ga ) about geo satellite using mpt has been probed after analysis of orbit dynamics, and building of mathematic model about geo satellite platform and each subsystem
通過geo衛星軌道動力學分析,建立了衛星總體和各子系統的數學模型。採用遺傳演算法( ga )對mpt用於geo的ot和nssk進行了系統和任務優化計算。Secondly, aiming at measurement being only from one satellite and the ekf being not stable, the measure equation is improved. transforming the form of angle measurements by the imaging theory, linearization of measure equation is realized by fake data of measurement. parameter of ballistic missile trajectory is estimated by using ekf, and the simulation shows that the unstabilization problem of ekf with true measurements is solved by using ekf with fake measurements
在僅有一顆預警衛星能夠觀測到目標的情況下,針對擴展卡爾曼濾波不穩定的問題,對觀測方程進行改進,利用光學成像系統的原理,將測量量進行變換,並利用新生成的偽測量量使測量方程線性化,再利用擴展卡爾曼濾波演算法對目標的彈道參數進行估計,最後,通過數學模擬來證明利用偽測量量的擴展卡爾曼濾波解決了單顆衛星觀測時利用真實測量量的擴展卡爾曼濾波不穩定的問題。分享友人