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
Many of his compositions are based upon dance forms and rhythms, such as mazurkas, waltzes, and polonaises
他的許多作品都是以舞蹈的形式和節奏為
基礎的,諸如馬祖卡舞曲、華爾
茲舞曲和波羅乃
茲舞曲。
At present, is included by the united nations the world culture and the natural heritage scenic spot historical site and the natural landscrape has 14, namely the london tower, ( the congress building ), the cloth roentgen heym palace ( nearby oxford ), the kanter uncle thunder host church, the buss city, salisbury suburb megalith and so on the vestige, the iron bridge canyon ( west of wool fertile hampton ), fang tingsi the monastery and the botanical garden ( york by north ), dallam ' s cathedral and the ancient castle, the harder good great wall ( area newcastle ), gwynedd ' s castle group ( area the welsh carnarvon ), scotland ' s saint kiel reaches the archipelago, north blue likes " road of the giant " being with pacific ocean ' s on england enjoys the german woods coral island
目前,被聯合國列入世界文化和自然遺產的名勝古跡和天然景觀就有14處,即倫敦塔、威斯敏斯特宮(國會大廈) 、布倫海姆宮(牛津附近) ,坎特伯雷主教堂、巴斯城、索爾
茲伯里郊區的巨石陣等遺跡,鐵橋峽(伍爾沃漢普頓以西) ,方廷斯修道院及園林(約克以北) 、達勒姆的大教堂和古城堡、哈德良長城(紐卡斯爾一帶) ,圭內斯的城堡群(威爾士卡那封一帶) ,蘇格蘭的聖
基爾達群島,北愛蘭的「巨人之路」和太平洋上的英國屬地享德森珊瑚島。
59 bronte, charlotte, the brontes : their lives, friends and correspondence ed. wise, j and j. a symington, oxford : oxford university press, 1980, p. 57
56 (法)吉爾?里波韋
茲基: 《第三類女性? ?女性地位的不變性與可變性》 ,湖南文藝出版社, 2000年版,第195頁, 197頁。
A simply and analytical formula of the axial light intensity distribution behind a circular aperture is derived by using the helmhotz - kirchhoff integral theorem and the kirchhoff ' s boundary conditions. it is studied the nonparaxial on - axis intensity distribution throughout the whole space behind a circular aperture. an accurate formula to calculate the fresnel number of circular aperture is presented and the validity of usual fresnel number formula is reexamined. by using the analytical formula and diffraction integral formula, some numerical simulation comparisons are done, and it is shown that the results of the two methods are completely coincident
用亥姆霍
茲-
基爾霍夫積分定理和
基爾霍夫邊界條件,推導出了平面波經小圓孔非傍軸衍射時軸上強度的簡單解析表達式,研究了平面波經小圓孔后整個衍射空間非傍軸的軸上光強分佈.給出了計算圓孔菲涅爾數的精確公式,重新檢查了通常的菲涅爾數公式的有效性.數值計算顯示,應用解析表達式所得的結果與應用衍射積分公式所得的結果完全一致
The next one is on monday, september 24th by professor roberta klatzky
下一個是9月24日,星期一,羅伯塔.克萊
茲基教授。
J. j. was telling us there was an ancient hebrew zaretsky or something weeping in the witnessbox with his hat on him, swearing by the holy moses he was stuck for two quid
傑傑告訴我們,有個叫扎列
茲基還是什麼名字的猶大老頭兒,戴著帽子330在證人席上哭哭啼啼,他以聖摩西的名字發誓說,自己被騙去兩鎊。
Mr fitzgibbon said it was more than two years since the dawson inquiry had recommended changing the trade practices act, and labor and the accc had consistently called for action
費特
茲基伯先生說,自道森調查案建議修訂貿易現行法案以來已兩年多了,勞動黨及澳大利亞競爭及消費委員會自始至終一直呼籲採取行動。
Labor ' s competition spokesman joel fitzgibbon said that prime minister john howard had been " obsessed " with passing his industrial relations laws, which were of " dubious economic value "
勞動黨競爭委員會發言人喬伊# 8226 ;費特
茲基伯說,總理約翰# 8226 ;霍華德對通過行業關系法一直「舉棋不定」 ,因為該法的「經濟價值還不明確」 。
We have so many questions about these plants remarks guenther stotzky a soil microbiologist at new york university. there ' s a lot we do n ' t know and need to find out
「我們對這類作物有太多的疑問, 」紐約大學土壤微生物學者史達
茲基說, 「我們不知道的多著呢,必須找出答案來。 」
1988 - 1992 enrolled at krasnoyarsk state art institute. among his teachers were a member of the russian academy of fine arts l. golovnitsky, prof
1988 - 92進入克雅斯諾亞斯克藝術學院就讀,他指導老師包括一名俄羅斯美術學院院士哥羅尼
茲基教授
This was the aircraft that was to begin boeing ' s recovery after years when its aeroplanes were outshone by the new models rolling out of airbus ' s hangars in toulouse
此前幾年,空客圖盧茲基地陸續推出的幾款新機型,總讓波音的客機相形見絀,正是穆拉利的777令波音公司重振旗鼓。