acoustic fatigue,声疲劳
    acoustic impedance,声阻抗
    acoustic logging instrument,声波测井仪
    acoustic malfunction,声失效
    acoustic matching layer,声匹配层
    acoustic(quantity)transducer【sensor】,声（学量）传感器
    acoustic ratio,声比
    acoustic releaser,声释放器
    acoustic resistance,声阻
    acoustic thermometer,声学温度计；声波温度表
    acoustic tide gauge,回声验潮仪
    acoustic transponder,声应答器
    acoustical frequency electric,声频大地电场仪
    acoustical hologram,声全息图
    acoustical holography,声全息
    acoustical holography by electron-beam scanning,电子束扫描声全息
    acoustical holography by laser scanning,激光束扫描声全息
    acoustical holography by mechanical scanning,机械扫查声全息
    acoustical imaging by Bragg diffraction,布拉格衍射声成像
    acoustical impedance method,声阻法
    acoustical lens,声透镜
    acoustically transparent pressure vessel,透声压力容器
    acquisition time,取数据时间
    actinometer,光能计；直接日射强度表；日射表
    (active)energy meter,（有功）电度表
    active gauge length,有效基长
    active gauge width,有效基宽
    active metal indicated electrode,活性金属指示电极
    active remote sensing,主动遥感
    active transducer【sensor】,有源传感器
    activity,活度 activity coefficient,活度系数
    actual material calibration,实物校准
    actual time of observation,实际观测时间
    actual transformation ratio of voltage transformer,电压互感器的实际变化
    actral transformation ratio of current transformer,电流互感器的实际变化
    actual value,实际值
    actual voltage ratio,实际电压比
    actuator,执行机构；驱动器
    actuator bellows,执行机构波纹管
    actuator load,执行机构负载
    actuator power unit,执行机构动力部件
    actuator sensor interface(ASI),执行器传感器接口
    actuator shaft,执行机构输出轴
    actuator spring,执行机构弹簧
    actuator stem,执行机构输出杆
    actuator stem force,执行机构刚度
    actuator travel characteristic,执行机构行程特性
    adaptation layer,适应层
    adaptive control,（自）适应控制