A large planar microphone array, which consists of 111 microphones, was successfully applied to obtain a two - dimensional mapping of the sound sources on a landing aircraft. the focus of study in this paper is on the landing gear noise source. the spectra, directivities and sound pressure levels of flap side - edge noise of 7 narrow - board commercial aircraft and 7 wide - board commercial aircraft are presented. it is found that the landing gear noise spectrum is broadband with some single tones in some cases. the directivity of the total sound pressure level of a landing gear noise resembles that of a horizontal dipole. the level differences between the various aircraft landing gears are larger than those expected from the airspeed differences. it is thus expected that the louder noise emission of the landing gears can be reduced by redesigning
應用由111個傳聲器組成的平面傳聲器陣列對當前流行的民用客機進場著陸過程中的機
體噪聲源進行了實驗測量,本文對七架窄
體客機和七架
寬體客機的起落架噪聲進行了分析,得到了起落架噪聲的頻譜特性、指向特性和聲級變化.研究發現,起落架噪聲的頻譜是由
寬頻隨機噪聲與一些較為明顯的單音噪聲源組成,起落架噪聲的指向性類似於一個水平放置的偶極子.不同飛機起落架噪聲的聲級相差較大,這說明可以通過重新結構設計降低起落架噪聲。
While asia will catch up with america and europe, the “ minor twist ” is that asian low - cost airlines will mostly rely on wide - body rather than single - aisle type of aircraft favoured in europe for shorter distances, according to mr leahy
李希表示,盡管亞洲將趕上美國和歐洲,但有個「小問題」是,在較短途運輸方面,亞洲低成本航空公司將主要依賴于
寬體機,而非在歐洲倍受青睞的單走道機型。
On 26th october 2006, china aviation supplies import and export group corporation ( casgc ) signed a general terms agreement ( gta ) for the purchase of 150 a320 family aircraft and a letter of intent ( loi ) for 20 a350xwb aircraft with airbus in beijing
2006年10月26日,空中客車公司與中國航空器材進出口集團公司在北京簽署了訂購150架空中客車a320系列飛機的框架協議和訂購20架a350
寬體飛機的意向書。
Besides, they don ' t hold grudges. they ' re bigger than that
另外,他們不會記仇的他們心
寬體胖
Abstract : a large planar microphone array, which consists of 111 microphones, was successfully applied to obtain a two - dimensional mapping of the sound sources on a landing aircraft. the focus of study in this paper is on the landing gear noise source. the spectra, directivities and sound pressure levels of flap side - edge noise of 7 narrow - board commercial aircraft and 7 wide - board commercial aircraft are presented. it is found that the landing gear noise spectrum is broadband with some single tones in some cases. the directivity of the total sound pressure level of a landing gear noise resembles that of a horizontal dipole. the level differences between the various aircraft landing gears are larger than those expected from the airspeed differences. it is thus expected that the louder noise emission of the landing gears can be reduced by redesigning
文摘:應用由111個傳聲器組成的平面傳聲器陣列對當前流行的民用客機進場著陸過程中的機
體噪聲源進行了實驗測量,本文對七架窄
體客機和七架
寬體客機的起落架噪聲進行了分析,得到了起落架噪聲的頻譜特性、指向特性和聲級變化.研究發現,起落架噪聲的頻譜是由
寬頻隨機噪聲與一些較為明顯的單音噪聲源組成,起落架噪聲的指向性類似於一個水平放置的偶極子.不同飛機起落架噪聲的聲級相差較大,這說明可以通過重新結構設計降低起落架噪聲。
Acute toxic effect of three pesticides - trichlophonus, the mixture of cupri sulf
三種常用魚藥對
寬體金線蛭的急性毒性作用
Morph beam : the fusing of an aerodynamic widebody head with a traditional, box - shaped shaft for greater resistance to twisting and a more solid feel
形態梁:符合空氣動力學特徵的
寬體拍頭和傳統的方型拍梁的結合,可以大大增強球拍的抗扭力水平,並提供更佳的球感。
In his prime, the portly singer known for his black beard and cheerful demeanor was a favorite of opera critics and audiences around the world
在他生涯鼎勝時期,這位以其黑鬍子和歡快風度著稱的身
寬體胖歌手深受全世界歌劇評論家和觀眾的喜愛。
Many asian low - cost airlines are opting not only for wide - bodied aircraft but also for a two - class model to lure business customers away from established carriers
許多亞洲低成本航空公司不僅選擇
寬體機型,而且還購買兩艙飛機,以便從老牌運營商那裡吸引商務乘客。
It is not only airbus employees and european governments that are anxiously contemplating the woes of airbus, particularly in the wide - bodied market where boeing ' s long - haul 777 and its new 787 are cleaning up
不僅僅是空客職員和歐洲各國政府對空客的困難處境倍感擔憂,尤其是在波音長途客機777和新787在
寬體客機市場獲利頗豐的情況下。
Laugh and grow fat
笑使人心
寬體胖。
Wide capacitance range, small size long life due to self - healing effect
容量范圍寬,體積小,比率容量大