新概念英语第一册63课课文

新概念英语第一册63课课文
Lesson 63 A glass envelope
In the previous lessons, we have learned about the history of the envelope. Today, we will introduce a new type of envelope called the glass envelope. A glass envelope is commonly used in the field of electronics and is an essential component of various devices such as vacuum tubes and light bulbs.
A glass envelope is a sealed glass container that protects delicate electronic components and ensures their proper functioning. It is made from high-quality borosilicate or soda-lime glass, which is known for its excellent thermal resistance and electrical insulation properties. The glass envelope is carefully designed to withstand high temperatures and pressure differentials, making it suitable for a wide range of applications.
The manufacturing process of a glass envelope involves several intricate steps. First, the glass is melted in a furnace at extremely high temperatures. The molten glass is then shaped into a tube or a bulb using various techniques, including blowing and pressing. Next, the tube or bulb is carefully cooled and annealed to relieve internal stresses and strengthen the glass structure.
After the glass envelope is formed, it undergoes a series of rigorous tests to ensure its quality and performance. The envelope is checked for any defects or impurities that may affect its functionality. Moreover, it is subjected to high-voltage tests to measure its electrical insulation properties and ensure it can withstand the required voltage.
Once the glass envelope passes all the tests, it is ready to be used in electronic devices. Vacuum tubes, for example, rely on glass envelopes to maintain a vacuum inside, which is crucial for their operation. Light bulbs also utilize glass envelopes to protect the filament and provide a controlled environment for the emission of light.
In conclusion, the glass envelope is an important component in the field of electronics. Its ability to withstand high temperatures and pressure differentials, along with its excellent electrical insulation properties, make it an ideal choice for various electronic devices. Without the glass envelope, many of the devices we use today would not be possible.。