beam n. 1.梁,栋梁,桁条;(船的)横梁。 2.船幅;(动物、人的)体幅。 3.(秤)杆,杠杆,(织机的)卷轴,经轴;(鹿角的)主干;车辕;犁柄;锄把。 4.(光线的)束,道,柱;【物理学】波束,射束。 5.(笑容、表情等的)焕现。 6.【无线电】有效播听范围。 7.【航空】信号电波,指向电波。 a beam of light 一束光线。 the common beam 标准秤;准则。 beam and scales 天平。 a beam of delight 高兴的表情,笑逐颜开。 an erector beam 【火箭】(发射时调整导弹位置的)千斤顶。 radio beam 无线电领航信号。 a landing beam 【航空】降落指示波。 abaft the beam = before the beam. a beam in one's eye 自己本身的大缺点〔与他人目中之刺相比,自己眼中有梁,源出《圣经》马太福音〕。 before the beam 【航海】正横前。 broad in the beam 〔口语〕臀部阔大。 fly the beam 【航空】按指向电波飞行。 fly the wet beam 【航空】顺着河流飞行。 kick [strike] the beam 1. (秤一方)翘起;过轻,不足抗衡,无足轻重。 2. 输,遭受失败。 off the beam 脱离航向,不顺利;不对头;做错。 on the beam 1. 【航海】与龙骨垂直地,正横地。 2. 在航向上;对头,做对。 on the port [larboard] beam 【航海】左舷正横前。 on the starboard beam 【航海】右舷正横前。 on the weather beam 【航海】迎着正横风。 ride the beam = fly the beam. vi. 1.辐射,发光,闪光。 2.微笑,眉开眼笑。 vt. 1.发射(光线、电波)。 2.向…放[播]送。 3.(用雷达)探测。 4.(用波束)导航(飞机等)。 beam the program at America 向美国播送节目。 the sun beaming overhead 红日当头照。 beam upon 看着…微笑。 beam with joy 眉飞色舞,笑逐颜开。
The beam orbit offset effects caused by the initial beam offset and linac componets " offsets in beam transferring process 良好的束流轨道可以获得低发射度、低能散的高品质束流。
The propagation of ultrashort laser pulse in air is analyzed with mechanics analogy by considering kerr effects and free electron defocusing . the equation describing the evolution of the laser spot is derived . it is shown that long distance focusing requires large initial beam and the propagation distance is very sensitive to the initial divergence angle of the laser beam 考虑多光子电离效应和光学kerr效应,首次利用力学类比的方法研究了超短脉冲激光在电离气体中的传输,详细分析了传输距离与激光初始光斑、初始发散角以及激光功率的关系,提出了实现长距离传输的条件。
We discuss the effect on the focusing of the probe beams for the five initial parameters : the amplitude of the pump beam , the separation between the pump and the probe beam centers , the wavelength ratio of the pump and the probe beams and the ratio of the initial beam widths at the directions of x and y . our numerical results show that , more the amplitude of the pump beam , the wavelength ratio of the pump and the probe beams and the ratio of the initial beam widths at the direction of y , more the probe focus ; the separation between the pump and the probe beam centers and the ratio of the initial beam widths at the direction of x have optimum values , respectively 研究了泵浦光束输入振幅、泵浦光束-信号光束初始偏移、泵浦光束-信号光束波长比和泵浦光束-信号光束x 、 y方向的初始束宽比五个参量对信号光束聚焦程度的影响。数值模拟结果表明,泵浦光束输入振幅越大、泵浦光束-信号光束波长比越大、 y方向束宽比越大,信号光束聚焦程度越大;泵浦光束-信号光束初始偏移和x方向初始束宽比都存在一个最佳值,使得光束聚焦达到最佳效果,有趣的是这两个最佳值的比值基本保持不变约为0 . 4 0 . 6 。
Secondly , the beam orbit offset effects caused by the initial beam offset and the linac components " offsets have been quantitatively studied first . as an example with the injector linac for beijing electron positron collider upgrading project ( bepcii ) , the beam orbit offset caused by the above error effects have been simulated and analyzed 其次定量研究束流的初始径向误差和加速器部件的安装误差等对束流轨道偏轴的影响,并以北京正负电子对撞机二期工程( bepc )的直线加速器为例,给出了上述各种误差导致轨道偏轴的模拟计算结果及其分析。