Mobile phone, mobile phone or English mobile phone.
Mobile phone is the abbreviation of portable phone, or mobile phone, which is also called mobile phone in Hong Kong. This is a portable wireless phone.
1one day in April, 973, a man stood on the street of new york, took out a wireless phone about the size of two bricks and made a call, which attracted passers-by to stop and stare. This man is marty cooper, the inventor of mobile phone. At that time, Cooper was an engineer of the famous Motorola company in the United States.
The first mobile phone in the world was called to an opponent who worked in Bell Laboratories in Alexandria. At that time, the other party was also developing mobile phones, but it has not been successful. Cooper later recalled: "I called him and said,' Joe, I'm talking to you on my mobile phone.' I heard the voice of "gnashing my teeth" on the other end of the phone-although he has always been quite polite. "Mobile phone.
This product of the competition of scientific and technological personnel in those days has blossomed everywhere now, which has brought great convenience to our modern life. Cell phone, cell phone, cell phone, cell phone.
Marty cooper is 74 years old. After working in Motorola for 29 years, he founded his own communication technology research company in Silicon Valley. He is currently the chairman and CEO of this company. Marty cooper's idea at that time was to let the media know that wireless communication, especially small mobile phones, was very valuable. In addition, he also hopes to arouse the interest of the Federal Communications Commission, and AT & amp； t(AT & amp； T is also a big communication company in the United States) and can support the former.
In fact, going back, we will find that the concept of mobile phone appeared as early as 1940s. At that time, the trial production was started by alexander bell Laboratory, the largest communication company in the United States. 1946, alexander bell laboratory made the first so-called mobile phone. But because of its large size, researchers can only put it on the shelf in the laboratory, and people will gradually forget it.
Until the end of 1960s, in&; Two companies, T and Motorola, became interested in this technology. At that time, at & amp； T Rent a large mobile radiotelephone, which customers can install on the truck. At&T Company. T's vision is to develop a mobile phone with the power of 10 watt in the future, and use the radio equipment on the truck to communicate. Cooper thinks this kind of mobile phone is too big and heavy to move and carry. Therefore, Motorola filed an application with the Federal Communications Commission, requesting that the power of mobile communication equipment can only be one watt, and the maximum power cannot exceed three watts. In fact, the maximum radio power of most mobile phones today is only 500 MW. Cell phone, cell phone, cell phone, cell phone.
From 1973 to 1985, the first modern mobile phone was born. It puts the power supply and antenna in a mobile phone, a mobile phone, a mobile phone.
But now the functions of mobile phones are getting wider and wider, and the main functions are different for different people!
For college students, even those with mobile phones, texting is the most important function. Some people only pay attention to the SMS function when buying mobile phones! Send jokes, harassment, love letters and so on!
However, for business people, the latest business stealth mobile phone is their first choice, which can provide powerful security functions and prevent the loss of important information (which may cause serious losses).
But for the average person, the function of calling in time is the most important!
Of course, some additional functions now are also promising! 30-1.3-2 million pixel mobile phones have become the favorite of many young people, and you can take wonderful moments when some unexpected events come or exciting moments!
Of course there are others, such as e-books! Cell phone, cell phone, cell phone, cell phone.
Matters needing attention when buying a mobile phone
First, choose a brand.
At present, there are many domestic and foreign mobile phone brands approved for sale by the national radio management department. Consumers mainly consider the reputation of brand mobile phone manufacturers, after-sales service, mobile phone quality and whether related accessories are easy to buy. Cell phone, cell phone, cell phone, cell phone.
Second, choose a good place to buy.
Now there are mobile phone counters everywhere. Whose home do consumers buy? At present, people can generally buy mobile phones through factory stores, telecom business halls, large and medium-sized shopping malls and general retail stores. Shopkeepers have the deepest understanding of manufacturers' products and complete accessories. After-sales service is not only direct, but also perfect and thoughtful. Buying in the business hall of China Telecom or China Unicom is relatively safe, with regular purchase channels and strong after-sales service technology, but the price is relatively expensive. Buying in large and medium-sized shopping malls is equally assured, with formal purchase channels and after-sales quality guarantee clauses. To buy in a general retail store, we must first confirm whether the store has a Mobile Communication Terminal Distribution License issued by the local telecommunications industry management department and a Sales License issued by the radio management department. Generally, the prices of retail stores are relatively low, but pay attention to their mobile phone configuration and after-sales service when buying.
Third, compare functions and choose appearance.
The more functions, the better. In fact, many functions are not needed at all. We should measure our own needs and compare them. Choose a mobile phone with simple operation and humanized design, which is very convenient to use in the future. For ordinary consumers, Chinese short message function is more practical. Consumers should pay special attention to whether the SMS input method is easy to use when purchasing. This seemingly simple function is actually very different between different mobile phones. The shape of the mobile phone should be reasonable, the appearance color should conform to the personality and occupation of the owner, and it should be easy to operate with one hand. Cell phone, cell phone, cell phone, cell phone, cell phone.
Fourth, the price
Usually wool comes from sheep, with complete functions, color screen and camera, small size and long standby time. Usually, everyone wants a mobile phone, but the price of a mobile phone that meets these conditions is also more expensive than that of a general mobile phone. Price is the most concerned indicator for buyers. For the same model, the prices of telecom business halls, manufacturers and general retail stores may be different. Please note when the price is low:
1. All distributed mobile phones must have the "network access license" of the Ministry of Posts and Telecommunications and the anti-counterfeiting mark, and the anti-counterfeiting mark will display the clear pink word "CMII" under the fluorescence of the money detector.
2. Pay attention to batteries at different price points at the same time. Whether the type and quantity of accessories are the same as the standard configuration of the manufacturer's franchise stores, whether the batteries and accessories are original from the manufacturer, and whether the distributor has quality assurance or corresponding written warranty commitment. Cell phone, cell phone, cell phone, cell phone, cell phone.
3. Enter "*#06#" on the mobile phone to see if the IMEI number displayed on the screen of the mobile phone matches the IMEI number on the back of the mobile phone (you can see it after taking out the battery), the IMEI number on the box of the mobile phone and the IMEI number on the yellow sticker, so as to judge whether the mobile phone motherboard has been replaced. Cell phone, cell phone, cell phone, cell phone.
Fifth, check the phone.
Configuration: battery, charger and earphone check whether the mobile phone packaging box has Chinese logo and is beautifully printed; Whether there are original Chinese instructions, original certificate and original battery; Whether the types and quantities of accessories such as fast chargers and charging stands are complete, whether they are made by manufacturers, and whether the power plugs meet Chinese standards.
The original high-end mobile phone battery is worth more than several hundred yuan, while the counterfeit battery is less than 100 yuan. Forced charging with fake batteries may cause explosion, so be sure to check it carefully. Cell phone, cell phone, cell phone, cell phone.
Six, check the after-sales maintenance service
Be sure to carefully check whether the original factory or its authorized special maintenance center provides one-year warranty and lifelong maintenance service. Seek the guarantee of regular agents to avoid having no recourse after buying parallel imports. Cell phone. Cell phone.
Study on the harm of machine radiation to human body
Background: In this era of rapid development of information technology, mobile phones have become more and more popular, but new problems have also emerged. How harmful mobile phone radiation is to human body has become a cross-century unsolved case, and no one can give a clear statement so far. Everyone knows that smoking is harmful to health, but there are still some people who are restless. When mobile communication has become the dependence of more and more people like cigarettes, people have fallen into a dilemma between health and convenience. However, the difference between mobile phones and cigarettes lies in where the danger lies, and people are still arguing ambitiously about where the danger lurks. This makes merchants always hang a sword on their heads, not knowing whether to drop it or remove it, which makes consumers panic. Known injuries can be prevented, and unknown fears are as worrying as the protagonist in The Man in the Condom. The harm of mobile phone to human body is imminent, because it is related to our health and the future development of mobile phone.
Research process: 1. Discuss research methods.
2. Search for relevant information online.
3. Collate the obtained data.
4. Summarize and write the paper.
Research results: Electromagnetic radiation from mobile phones can cause neurasthenia, loss of appetite, loss of libido, palpitation, chest tightness, dizziness, listlessness and other diseases, and may even induce brain tumors. Mobile phone users are more likely to die of brain cancer, and the chances of suffering from extra-brain tumors are doubled. Endangering fertility and causing fetal malformation. Frequent use of mobile phones can make people aging, just as people who smoke often age quickly. Low-level radiation from mobile phones will accelerate cell activity. Medical circles believe that tumors, heart diseases and Alzheimer's disease are all caused by radiation. When cells are affected, the biological defense system will be activated, and protein will be produced to "attach" to cells to protect and repair them. However, for heavy users of mobile phones, too much protein will "stick" to cells and hinder natural patching. Cells will slowly fail to function normally, and metabolism will become slow. If the cell repair activity is excessive, premature aging will occur.
Example 1: The researchers also conducted a mobile phone volunteer experiment in the Royal British Hospital. They were connected to a transmitter in their heads, and within an hour, half of them received the microwave from the 9 15 MHz mobile phone, while the other half didn't. Followed by psychological tests to determine the affected brain. The results show that the memory and attention of a group of people who have not received microwave radiation are better or the same as before, while those who have received microwave radiation are generally worse than before. Cell phone, cell phone, cell phone, cell phone.
Example 2: An expert who specializes in mobile phones at the University of Washington in the United States once experimented with mice. Put a hundred mice in a big bucket full of water, put a life-saving floating platform in the water, and then train these mice to climb the life-saving floating platform. In order to keep the knowledge of climbing the floating platform in the long-term memory of the mice, he trained the mice six times repeatedly. The expert exposed 50 mice to microwave radiation similar to mobile phones, and found that the other 50 mice that were not exposed to microwave radiation could still get out of the water easily. However, the mice affected by microwave almost lost their memory and didn't know how to climb the floating platform. Cell phone, cell phone, cell phone, cell phone, cell phone.
Status quo: To sum up, the harm of mobile phone radiation is very terrible. However, we can avoid cell phones, cell phones, cell phones, cell phones, cell phones.
Methods 1: Reduce the use of mobile phones. Method 2: Use a hands-free mobile phone to avoid the phone touching the ear.