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Term | 术语 | Definition | 定义 |
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free wave | 自由波
| See WAVE. | 一种产生作用力停止作用后仍然继续存在的波,与由连续作用力产生和保持的强迫波相反。水面上的自由... more |
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freezing | NULL | See FROST. | NULL |
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freezing point | 冰点
| Temperature of solidification of a liquid in given conditions. | 在一定的环境中,液体变成固体所要求的最低限度的温度。 |
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frequency | 频率
| The number of VIBRATIONS or CYCLES in unit time. | 单位时间内的振动次数或者周期数。 |
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frequency: extremely high (EHF) | NULL | See FREQUENCY: RADIO. | NULL |
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frequency: high (HF) | NULL | See FREQUENCY: RADIO. | NULL |
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frequency: low (LF) | NULL | See FREQUENCY: RADIO. | NULL |
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frequency: medium (MF) | NULL | See FREQUENCY: RADIO. | NULL |
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frequency: natural | 固有频率,自然频率
| The lowest resonant FREQUENCY of a body or system. | 物体或系统的最低谐振频率。 |
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frequency: radio | 无线电频率 | Any FREQUENCY at which electromagnetic RADIATION of energy is useful for communication. Radio frequencies are usually classed as very low, b... more | 无线电通信中,电磁波的有效辐射频率。无线电频率通常分为:甚低频(30千赫以内)、低频(30-300千赫)... more |
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frequency: resonant | 谐振(共振)频率
| Any FREQUENCY at which a body or system vibrates more readily. | 物体或系统的固有振动频率。 |
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frequency: super high (SHF) | NULL | See FREQUENCY: RADIO. | NULL |
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frequency: ultra high (UHF) | NULL | See FREQUENCY: RADIO. | NULL |
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frequency: very high (VHF) | NULL | See FREQUENCY: RADIO. | NULL |
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frequency: very low (VLF) | NULL | See FREQUENCY: RADIO. | NULL |
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frequency band | 波段、频带
| See BAND OF FREQUENCY. | 参见band of frequency(频带)。 |
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frequency channel | 频道
| See CHANNEL. | 频谱中适合某一使用特定发射类别播送的一个连续部分。 |
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frequency modulation | 调频
| See MODULATION. | 对正弦载波的角度调制。调制波的瞬时频率与载波频率的差值,与调制波(幅度)瞬时值成正比。 |
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frequency of soundings | 测深密度 | See DENSITY OF SOUNDINGS. | 参见density of soundings(测深密度)。 |
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freshet | 淡水区,暴涨,山洪
| An area of comparatively fresh water at or near the MOUTH of a STREAM flowing into the SEA. A FLOOD or overflowing of a RIVER caused by he... more | 位于流入海的河口附近的淡水区。由于大雨或者冰雪融化而引起的洪水或者河水流量过大。 |