射電天圖 的英文怎麼說
中文拼音 [shèdiàntiāntú]
射電天圖
英文
radio map-
Above this 34 - m antenna, called dss - 13, is one of those large dishes of the deep space network in goldstone, california and is primarily used for receiving echoes reflected from asteroids when they are beamed by groundbased radio signals
圖上這座口徑34米的天線，編號dss - 13 ，隸屬美國加州的深空網路。當天文學家從地面向小行星發射無線電波時，小行星會把部分電波反射回地球，並由dss - 13所接收。Above ) this 34 - m antenna, called dss - 13, is one of those large dishes of the deep space network in goldstone, california and is primarily used for receiving echoes reflected from asteroids when they are beamed by groundbased radio signals
（圖上）這座口徑34米的天線，編號dss - 13 ，隸屬美國加州的深空網路。當天文學家從地面向小行星發射無線電波時，小行星會把部分電波反射回地球，並由dss - 13所接收。It was not until years later that the first all sky radio map was obtained by amateur astronomer grote reber, who had spent lots of effort in the measurement. he found that there was a fundamental difference
直到后來，經過一位業餘天文學家雷柏grote reber多年的努力和認真地做這方面的測量，才得到一幅全天的射電圖。Radio astronomers are now able to synthesize the response of a partially filled aperture of large diameter and thus to map variations in nebular brightness.
射電天文學家現在已經能夠把部分充滿的大直徑孔徑進行綜合，從而描繪出星雲亮度變化圖。In order to obtain the complex rcs of the target quickly in high frequency band, the graphical electromagnetic computing software, greco, is used. the modification of the computing kernel code is presented. the judgement of edges of complex targets is more sufficient and the computation of edge wave based on physical theory of diffraction ( ptd ) is more exact after the modification
為了可以準確地預估雷達目標的rcs ，我們對于航天部207所的圖形電磁計算軟體（ greco ）進行了進一步的開發與包裝，用borland公司的c + + builder開發了更加易於使用的基於windows操作系統的新版greco ，並且在考察了原有的greco計算內核之後，結合計算機圖形學方面的理論，對greco的內核代碼進行了改進，整體上使得邊緣繞射場的計算結果更加準確。A patch antenna with air holes in the substrate has been designed. the finite - difference time - domain ( fdtd ) method together with the perfectly matched layer ( pml ) boundary treatment has been used to study the performance of the antenna. it is shown that the surface waves are significiently suppressed, the frequency bandwidth is improved, the sidelobe levels are reduced and consequently the gain in the forward direction is improved by 14 db ( about 4 db higher than the value reported previously )
設計了一種基底鉆周期圓孔結構的電磁（光子）晶體貼片天線，用fdtd方法並結合pml吸收邊界條件對該天線進行了研究，結果表明本文所設計的基底鉆孔型電磁晶體貼片天線取得了多方面的性能改善，與普通天線相比，基底中的表面波受到很大抑制，天線的帶寬增加，遠場方向圖上天線的旁瓣和背瓣被明顯削弱，向前輻射的增益由原來的12db增加到26db ，增加了14db ，比文獻上報道的gonzalo等人的研究結果提高了4db 。However, radio telescopes do have their own shortcoming. firstly, radio astronomical images are not as fascinating as optical images. moreover, they do not work like optical telescopes which can receive all visible wavelengths and then produce monochromatic signals by means of filters
可是，射電天文望遠鏡也有它的缺點，首先射電天文圖像並沒有光學照片那麼具美感，而且它不像光學望遠鏡般，可以把可見光全部接收，然後加上濾色片分出單色光。The performance of the pbg antenna using the new pbg cover together with a pbg substrate is studied by the fdtd method together with the pml boundary treatment. the numerical results show that a more focused beam radiated in the broadside direction is achieved. the gain of the pbg patch antenna in the forward direction is improved by about 6 db. the radiation directivity is improved significantly and reaches 11. 5 db, which is 0. 4 db less than the maximum value that is allowed physically for this size of the antenna ( this difference is about 4. 1 db less than the difference achieved by thevenot et al.,
用fdtd方法並結合pml吸收邊界條件，我們對加了這種新的覆層結構並且基底鉆孔的復合結構電磁（光子）晶體貼片天線的性能進行了研究，結果證明加了這種新的電磁晶體覆層結構以後，天線的波束收攏很多，並且向前輻射的增益大大提高，與普通天線相比，天線的e面和h面方向圖上向前輻射的增益均提高了約6db ，另外，該復合結構天線的方向性系數達到了11 . 5浙江大學博士學位論文db ，與該物理尺寸天線的方向性系數的理論極限值（ 11 . 9db ）相差0 . 4db ，該差值比thevenot等人設計的電磁晶體覆層天線的相應差值減少了約4 . 1db ，比qiu等人設計的電磁晶體天線的相應差值減少了約1The special selections for this year include : pic du midi observatory in southern france, the 100 - m - diameter radio telescope in west germany, mare lmbrium area of the moon, milky way, voyager 2 encounters neptune and the m31 galaxy of andromeda
選輯的十二幅珍貴天文圖片包括：法國日中峰天文臺西德一百米口徑射電望遠鏡月面雨海地區銀河航行者二號飛越海王星仙女座大星系m31等。After the discussion of the numerical simulation method based on the fdtd method and the pml technique, the motions of the charges and the electrical field lines were first employed to describe the radiation procedures of the pulse electromagnetic waves. then the causes of how the charges are accelerated and how the motion status of the charges are maintained were further studied from the angle of interaction of charge and field. after these analyses, it was pointed out that the pulse radiation is due to the suddenly occurred time - varying electrical field ( displacement current ) in the open space. this view was further evidenced by two examples : one is the partly resistance loaded antenna, the other is the partly curved antenna. the radiation procedures of the pulse electromagnetic waves of many different situations were simulated throughout this paper with the contours and waveforms of electric field given. these figures are very helpful to the understanding of the radiation mechanism of the pulse electromagnetic waves
在討論了基於時域有限差分法和完全匹配層技術的數值模擬方法之後，首先從運動電荷和電力線的角度直觀地描述了脈沖電磁波的輻射過程，然後進一步從場與電荷相互作用的角度分析了天線上電荷是如何被加速以及如何維持其運動狀態的，指出了開放空間中突然出現的時變電場（位移電流）是脈沖電磁波輻射的根本原因.文中還對局部電阻加載的天線和局部彎曲的天線進行了研究，以進一步說明上述觀點.對多種情況下的脈沖輻射過程進行了數值模擬，並給出了電場的等高線和空間波形圖，這些圖形對理解脈沖電磁波的輻射機理非常有益Conclusion dynamic picture angiography with digital subtraction using non - ionic contrast medium under rapid injection is the key for claiming the high quality imaging diagnosis of congenital heart disease in children
結論對于兒童先天性心臟病心血管造影而言，使用動態電影攝片，作數字血管減影，採用軸位成角投照技術，使用非離子型對比劑和快速注射對比劑是取得高質量圖像和理想診斷效果的關鍵。Furthermore the " microflare theory " tried to discuss and find the elementary flares in small space and time scale which might form and trigger the whole solar flare. the detection of radio fine structures showed many observational evidences of " microflare ". the observations and theoretical researches on radio fine structure have been developed fast recently and played an important role in solar radio astrophysics
著名的「微耀斑理論」 ，試圖從較小的時間、空間尺度范圍探究太陽耀斑形成和觸發的基本單元，而射電精細結構是微耀斑理論的重要觀測基礎，對射電精細結構的觀測和理論研究已成為太陽射電天文學中快速發展的領域，對揭示太陽活動源區的物理本質具有重要的意義。分享友人