STEM与日常科技·英语30篇（7）

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为什么LED灯泡寿命长得多

LED bulbs produce light through electroluminescence—electrons moving across semiconductor materials—not by heating a filament.
Because there’s no fragile wire to burn out, they avoid the main failure mode of incandescent bulbs.
Heat management is critical: excess heat degrades LED chips, so aluminum heat sinks draw warmth away efficiently.
Drivers convert household AC power to stable DC current, preventing voltage spikes that shorten lifespan.
Well-designed LEDs maintain 70% of original brightness after 25,000–50,000 hours—over 15 years of typical use.
Frequent switching doesn’t affect them, unlike fluorescents whose electrodes wear faster with each start.
Color consistency stays high over time thanks to phosphor coatings that convert blue light to white evenly.
Their directional output reduces wasted light, making fixtures more efficient without reflectors or shades.
Recycling programs now recover rare earth elements and gallium used in chip production responsibly.
In short, solid-state physics, thermal engineering, and electronics combine to redefine lighting longevity.

听 → 读 → 学表达 → 懂 → 今天会说这一句 → 跟读录音 → 自己说一句。

In short, solid-state physics, thermal engineering, and electronics combine to redefine lighting longevity. 简言之，固态物理、热工工程与电子技术共同重新定义了照明产品的使用寿命。
LED bulbs produce light through electroluminescence—electrons moving across semiconductor materials—not by heating a filament. LED灯泡通过电子在半导体材料中移动产生电致发光，而非加热灯丝。
Frequent switching doesn’t affect them, unlike fluorescents whose electrodes wear faster with each start. 频繁开关不会影响LED寿命，而荧光灯每次启动都会加速电极损耗。

这篇中文题目最接近哪一句？为什么LED灯泡寿命长得多一次学校运动会的通知一份超市购物清单

课文第一句的意思更接近？ LED灯泡通过电子在半导体材料中移动产生电致发光，而非加热灯丝。今天学校放假了。请把窗户打开。

这一课主要在讲什么？（看英文标题） Why LED Bulbs Last So Much Longer How to cook noodles A maths worksheet

In short, solid-state physics, thermal engineering, and electronics combine to redefine lighting longevity.

In short, solid-state physics, thermal engineering, and electronics combine to redefine lighting longevity.

第一版：录下来、回听、再听标准音。系统打分以后再加。

用今天的表达，自己说一句。

例子：In short, solid-state physics, thermal engineering, and electronics combine to redefine lighting longevity.