タイトルまたは説明

材料在声音中起着重要作用，声音在空气或物质中传播，最终转化为消失的热能。声波的传输在重金属中几乎没有衰减，在较轻的金属或塑料中很容易衰减，因此高档听诊器必须使用不锈钢甚至钛等重金属。The sound transmission line is also important. The larger the inner diameter of the tubing, the shorter the length, and the thicker the tube wall, the better the stethoscope will work, and the international standard length is *7 inches. The material of the sound transmission pipeline of modern stethoscope is generally PVC, which has good sound effect and beautiful appearance, but has poor stretch resistance, and is often bent and easy to break after stretching. The stethoscope should be hung flat on both sides of her neck after use, which can be seen in foreign TV dramas and is the standard way to wear a high-quality stethoscope.