The diameter of a sphere is four times the focal length of a concave mirror cut from it.
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2. 藉由改变气球内的气压，就可以调整气球反射给太阳能电池的光线焦距，还有气球内的凹面镜弧度。
The focus of the light on the solar cell can also be fine-tuned by changing the air pressure within the balloon, and thus the curvature of the mirror.
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3. 借由改变气球内的气压，就可以调整气球反射给太阳能电池的光线焦距，还有气球内的凹面镜弧度。
The focus of the light on the solar cell can also be fine-tuned by changing the air pressure within the balloon, and thus the curvature of the mirror.
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4. 除了凹面镜，能量塔以外，还有第三种新的太阳能热技术。结合了曲线，盘状镜面和热发动机的装置。
In addition to parabolic troughs and power-towers there is also a third solar-thermal technology, which combines curved, dish-shaped mirrors with heat engines.
The laser consists of a semiconductor laser with single mode fiber coupled output, polarization controller, PLZT electro-optic ceramic deflector, and output concave mirror.
Cool Earth's insight was that if you coat only one half of a balloon, leaving the other transparent, the inner surface of the coated half will act as a concave mirror.
Cool Earth's insight was that if you coat only one half of a balloon, leaving the other transparent, the inner surface of the coated half will act as a concave mirror.
Cool Earth's insight was that if you coat only one half of a balloon, leaving the other transparent, the inner surface of the coated half will act as a concave mirror.
