衰减

• Pinyin: shuāi jiǎn
• Hanzi breakdown: 衰 = 衣 + internal decreasing shape (garment radical + waning shape — to decline; to diminish); 减 = 氵 + 咸 (water + all/encompassing — to reduce; to subtract)

Meaning

To attenuate; to weaken; to diminish in strength or magnitude; to decay (of a signal, force, or effect).

Physics and engineering: signal attenuation (信号衰减), power loss. Biology: immune response weakening, radioactive decay. Economics and demographics: labour force decline, purchasing power erosion. Implies a measurable, gradual, quantifiable reduction.

Examples

1. 基站设计必须精确计算信号在不同频段、材料和天气下的衰减，才能保证覆盖区信号足够强。 Base station design must precisely calculate signal attenuation across different bands, materials, and weather conditions to ensure sufficiently strong signal in the coverage area.
2. 随着老龄化加深，劳动年龄人口比例持续衰减，正成为拖累发达经济体长期增长的重要因素。 As population ageing deepens, the continued attenuation of the working-age population share is becoming an important factor dragging down the long-term growth of many developed economies.
3. 核废料的放射性衰减要持续数千年，深地质处置库必须长期保持完整和隔离，要求极高。 The radioactive attenuation of nuclear waste lasts for thousands of years, so deep geological repositories must remain intact and isolated for the long term, which sets extremely high requirements.

Usage Guide

Context: physics, engineering, medicine, economics, demographics

Tone: technical

Do Say

• 光纤传输的衰减主要来自散射和弯曲损耗，单模光纤在超长距离传输中更具优势。(In fiber-optic transmission, attenuation mainly comes from scattering and bending loss; single-mode fiber has a clearer advantage in ultra-long-distance transmission.)
• 部分创伤后应激障碍患者难以恢复，不是记忆更强，而是情绪衰减机制失灵，恐惧长期偏高。(Some patients with post-traumatic stress disorder struggle to recover not because the memory is stronger, but because the mechanism that attenuates emotion has failed, leaving fear elevated for a long time.)

Don't Say

• 衰减 when describing the weakening of a person's physical strength or health in everyday contexts — use 衰退 (to decline) or 减弱 (to weaken) instead; 衰减 carries a technical, quantitative connotation of measurable attenuation and sounds clinical or overly technical when applied to general human decline

Origin & History

衰 (to decline; to diminish — 衣 garment radical + a decreasing interior shape, evoking something waning) + 减 (to reduce; to subtract — 氵water + 咸 all/encompassing)

Cultural Context

Generation: All ages

Social background: Universal