1.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.
应用由111个传声器组成的平面传声器阵列对当前流行的民用客机进场着陆过程中的机体噪声源进行了实验测量，本文对七架窄体客机和七架宽体客机的起落架噪声进行了分析，得到了起落架噪声的频谱特性、指向特性和声级变化.研究发现，起落架噪声的频谱是由宽频随机噪声与一些较为明显的单音噪声源组成，起落架噪声的指向性类似于一个水平放置的偶极子.不同飞机起落架噪声的声级相差较大，这说明可以通过重新结构设计降低起落架噪声。
2.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:应用由111个传声器组成的平面传声器阵列对当前流行的民用客机进场着陆过程中的机体噪声源进行了实验测量，本文对七架窄体客机和七架宽体客机的起落架噪声进行了分析，得到了起落架噪声的频谱特性、指向特性和声级变化.研究发现，起落架噪声的频谱是由宽频随机噪声与一些较为明显的单音噪声源组成，起落架噪声的指向性类似于一个水平放置的偶极子.不同飞机起落架噪声的声级相差较大，这说明可以通过重新结构设计降低起落架噪声。
3.This article for the most part of introducing Landing gear system of Airbus-A320 aircraft,braking system by way of parenthesis.The landing gear system includes landing gear parts,landing gear doors and Extension and Retraction system.
正文:本文主要讲述了空客A320飞机的起落架系统，包括有起落架部件、起落架舱门还有起落架的收放系统，附带介绍了飞机的刹车系统。
4.The simulation results showed that the automatic landing control law had exact output tracking ability, and the automatic landing process met federal aviation administration (FAA) requirements for the category III precision approach landing. The internal dynamic of aircraft was stable and bounded.
仿真结果表明,自动着陆控制律具有精确跟踪能力,自动着陆过程满足美国联邦航空局III类精密进场着陆要求,并且飞机内部动态稳定有界.
5.In the spring and summer of 2001, both Nanjing and Guangzhou military area commands organized field exercises with joint landing operations as the backdrop, focusing on the coordination of joint and combined arms landing operation, and drew useful lessons on how to organize, support and manage joint training, ground force amphibious landing training, and training of rapid reserve mobilization.
２００１年春夏季节，南京、广州军区部队分别组织了以联合登陆作战为背景的实兵演习，演练了诸军兵种联合登陆作战的协同方法，总结了联合训练、陆军部队两栖训练、国防后备力量快速动员训练等方面的一整套训练、保障和管理经验。
6.And then you come to the second landing. The second landing provides a panoramic lookd at the city.
然后，您再到第二个平台，可以看到巴黎的全景。
7.The contact, or moment of contact, of a landing aircraft or spacecraft with the landing surface.
触地、触地时刻着陆的飞机或太空飞行器与着陆平面的接触或接触的时刻
8.Methods Fatigue level of 47 airline aircrew of different age groups were measured with critical flicker frequency(CFF) test and cross out test on the day before flight,3 times during the across time zone flight(at the end of 3,6,9 h),on the day of landing,1 d,2 d after landing.
方法采用临界闪光融合频率(CFF)检测、划消测验等方法,对执行不同航线跨时区运输任务的中国国际航空公司47名男性飞行人员(年龄27~58岁),在飞行前1 d、空中飞行3 h、6 h9、h和落地后当天、第2天、第3天晚上睡觉前进行7次测试。
9.an emergency landing under circumstances where a normal landing is impossible (usually damaging the aircraft).
正常的降落不可能时的紧急着陆（通常会损坏飞机）。
10.Jet planes cannot he stacked up at the landing site while awaiting landing instructions.
不能在喷气式飞机等候着陆指令时让它们在着陆点上空分层盘旋。
