[通信] 极低频
But the extremely low frequency (ELF) magnetic fields generated by such cables may cause disturbances to nearby electronic apparatus and may even affect the human health.
这种重载流电缆周围的极低频磁场可能干扰附近敏感电子设备的正常运行，甚至影响暴露于该场下的人体的健康。
Conclusion Extremely low frequency electromagnetic field conspicuously restrained the growth status of tumor cells, and some tumor cells could be induced to apoptosis by EMF.
结论极低频率电磁场对肿瘤细胞有明显抑制作用，在一定程度上诱导肿瘤细胞的凋亡。
Objectives To investigate intensity of extremely low frequency magnetic field (ELFMF) emitted from cathode-ray tubes (CRT) of monitors in various directions and to find ways to avoid its influence.
目的研究电脑阴极射线管显示器正前方不同距离和不同方位的极低频磁场（ELFMF）强度，就如何减少ELFMF的影响提出初步建议。
The important frequencies for stimulating tissue repair are all in the biologically important extremely low frequency (ELF) range.
为促进组织修复的重要频率在生物的重要极低频所有（低频）的范围。
This analytic method is also suitable for the bands of extremely low frequency (ELF) and very high frequency (VHF).
这种分析方法也适用于极低频到甚高频波段。
The purpose of this review is to help people having a right attitude toward the health effects of expo-sure to extremely low frequency (ELF) electromagnetic fields.
旨在使人们对环境极低频电磁场暴露的健康效应有一个正确的认识。
These are quasi-standing extremely low frequency (ELF) waves that naturally exist in the earth´s 'electromagnetic´ cavity, the space between the ground and the ionosphere.
这些是天然地存在于地球的“电磁”空腔——地面和电离层之间的空间中的极低频（ELF）准驻波。
The current situation, present questions, future research direction of effects and application of extremely low frequency electromagnetic field on human health are introduced in this paper.
简要介绍了极低频电磁场对人类健康的影响和应用研究的现状、存在问题及未来研究方向。
Objective To explore the relationship between extremely low frequency (ELF) magnetic fields and carcinogenesis.
目的探讨极低频（ELF）磁场可能存在的促癌或协同促癌作用。
Objective To study the effects of extremely low frequency electromagnetic field(ELF EMF) and its combination with lead on the antioxidant system in mouse brain and liver tissues.
目的研究极低频电磁场及其与铅的联合作用对小鼠脑和肝脏抗氧化系统的影响。
A circuit network is used to further compensate the low frequency characteristics and a novel type of inertial extremely low frequency transducer is obtained.
在此基础上，用电路网络对磁电式检波器的低频特性作进一步的校正，得到了惯性式特殊低频传感器。
Extremely low frequency ( ELF)refers to an electromagnetic field having a frequency much lower than the frequencies of signals typically used in communications.
超低频是指一种非常低频的电磁场，它的频率比一般通讯信号使用的频率低得多得多。
The extremely low frequency electromagnetic fields (ELFEMF) were very related to humans health and living environment and its biological effects were more and more interested to scientists.
极低频电磁场（ELFEMF）与人类的生存环境及健康密切相关，其生物学效应也倍受关注。
This falls in the extremely low frequency (ELF) range which includes frequencies up to 300 Hz.
这种频率属于极低频的频率范围内，通常极低频的频带范围也在300Hz以下。
Major occupational hazard factors at the plant stu***d included dust, noise, poisonous chemicals, and extremely low frequency electric field.
结果显示：该厂的职业病危害因素主要有粉尘、噪声、毒物、工频电场等。
The ELF (extremely low frequency) waves cause entrainment of millions of Americans to occur, possibly to influence the election.
超低频波影响造成数以百万计的美国人，可能影响选情。
This makes achieving negative permeability under extremely low frequency as well as the permeability switching between positive and negative value rapidly through a magnetic field pulse into possible.
这使实现极低频的负磁导率以及通过磁场脉冲实现磁导率在正负之间快速跳变成为可能。
The biological effect of extremely low frequency(ELF)electromagnetic field on human body is a question in dispute.
低频电磁场是否对人体或生物存在不良影响 ，一直是学者们争议的课题。
No data relevant to the carcinogenicity of static electric or magnetic fields and extremely low-frequency electric fields in experimental animals were available.
静态电磁场和超低频电场对实验室动物致癌性的相关数据未提供。
There is inadequate evidence in experimental animals for the carcinogenicity of extremely low-frequency magnetic fields.
超低频磁场对实验室动物致癌性证据不足。
There is inadequate evidence in humans for the carcinogenicity of static electric or magnetic fields and extremely low-frequency electric fields.
静态电磁场和超低频电场对人类致癌性证据不足。
Extremely low-frequency magnetic fields are possibly carcinogenic to humans (Group 2B).
超低频磁场可能对人类致癌。
Static electric and magnetic fields and extremely low-frequency electric fields are not classifiable as to their carcinogenicity to humans (Group 3).
静态电磁场和超低频电场不具备对人类的致癌性。
Callus was induced from segments of leaf and hypocotyls from seedlings, but bud differentiation frequency was extremely low , approximately1%.
无菌实生苗的胚轴和叶片切段均可诱导形成愈伤组织，但不定芽的分化率极低，仅约1%。
As far as cased-hole formation resistivity logging, the key problems needed to be solved are detection of ultra-low frequency and extremely weak signals, as well as reduction of strong interferences.
超低频、纳伏级信号的检测以及强干扰的抑制是过套管地层电阻率测井需要解决的关键问题。
In high frequency communication, extremely low SNR communication is an expe***nt means.
在短波通信中，极低信噪比条件通信是一种应急通信手段。
Low loss at high frequency, extremely small inherent temperature rise, high reliability.
高频损耗小，内部温升极小，可靠性高。
Extremely low leakage current, standard size. Used in TVs frequency channel conversion or weak signal import loop circuits.
良好的低漏电特性，标准尺寸。适用于电视机频道转换或小信号输入回路。
It can reach control object quickly without vibration, so is extremely suitable for industrial control such as machine tool of low frequency response.
可快速、无振荡抵达控制目标，特别适用于机床等响应速度不高的工业控制。
extremely low frequency (ELF) 指极低频，是电磁波频谱中频率范围最低的波段之一。其具体定义和特性如下：
ELF 频段的频率范围通常被定义为3 Hz 至 30 Hz（依据国际电信联盟 ITU 的标准。这一频段紧邻超低频（SLF，30–300 Hz），属于无线电频谱中波长最长（可达数千公里）、穿透能力最强的波段。其物理特性源于电磁波在极低振荡频率下的传播行为。
ELF 波可穿透海水至百米深度及地壳岩石层，远优于高频信号。此特性源于趋肤效应随频率降低而减弱，使电磁场能深入导体内部。
波长与地球直径相当（如 30 Hz 波长约 10,000 km），可在电离层与地表形成的波导中绕地球传播，实现跨洲际通信。
受限于窄带宽（通常仅几赫兹），传输速率极低（约每分钟数个字符），仅适用于特殊场景下的指令传输。
各国海军利用 ELF 与深海潜艇通信（如俄罗斯 "ZEVS" 系统、美国 "Project Sanguine" 系统），实现无需浮标的水下指令接收。
用于监测地壳电磁场变化（如俄罗斯 "Intercosmos" 卫星），辅助地震前兆研究和矿产勘探。
分析雷电激发的 Schumann 共振（7.83 Hz 基频），研究全球闪电活动与电离层特性。
（注：来源依据国际权威机构公开标准文件，具体参数可查阅 ITU-R 数据库或 IEEE Xplore 文献库。）
"Extremely Low Frequency"（ELF，极低频）是电磁波频谱中的一个特定频段，具体解释如下：
ELF指频率范围在3Hz到3kHz之间的电磁波。其波长极长，介于100,000公里至100公里之间，属于无线电波中的超长波段。
ELF是"Extremely Low Frequency"的缩写，在通信和电子工程领域广泛使用。
扩展提示：ELF频段因对人体和环境影响的研究较少，其安全性存在一定争议。若需了解具体军事应用案例，可参考权威通信工程文献或军事技术报告。
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