1, if there is only one magnetic pole, the magnet in the plastic box is opposite to the magnetic pole on the book, the two cancel out, and it will be degaussed.
2, when degaussing, you can see the salesman put the book on a plastic box, that is, degaussing: there is a magnetic pole opposite to the magnetic pole in the plastic box, because the magnetic pole on the book is generated by the friction between the book and the magnetic pole, so there is only one magnetic pole, the magnet in the plastic box is the opposite of the magnetic pole on the book, the two offset, and the degaussing.
3, charge desensitization instrument: used to put the composite magnetic in the bookStrip magnetization or demagnetization. Back check instrument: used to check whether the magnetic strip in the book is intact.
4, through the magnetic strip and detector to induction. The library has a large collection of books, will encounter problems such as book theft, queuing for a long time to borrow and return books, can not quickly and accurately inventory books, the library has studied the anti-theft system, mainly the use of "magnetic stripe detector" system, the principle is magnetic induction, the book is equipped with magnetic stripe, when borrowing in the degaussing machine degaussing, take out the access control will not be induced alarm.
5, ④ the book that has not gone through the normal procedures (the book that has paid the magnetic stripe)id=' How to judge whether the ID card has magnetism '> How to judge whether the ID card has magnetism
To verify whether the ID card is degaussed, you can take the ID card to the nearby bank, hotel machine brush, check whether the information can be read normally, if yes, it indicates that the ID card has not been degaussed, can be used normally, if not, you need to re-apply for a new ID card.
The method of identifying the loss of magnetic ID card is as follows: there is no loss of magnetic ID card as long as you go to the place where the card is swiped to brush it, as long as you can sense and make the sound of swiping the card, it proves that it is magnetic. For example: Internet cafes, airports,Bank, school Express. The second generation ID card has a contactless IC card chip, in which the user's personal information is written, consistent with the information on the ID card.
The way to verify whether the ID card is demagnetized is to go to the nearest police station or a place with a card reading function, such as an Internet cafe. Use the ID card for credit card operation, if you can display personal information, it indicates that the ID card is not demagnetized. If personal information cannot be displayed, it indicates that the ID card may have been demagnetized. It is important to understand that the ID card itself is not magnetic and cannot be re-magnetized like a magnetic card.
Read with ID cardCard device, observe the appearance of the ID card. Put the ID card on the card reader, if the card reader can successfully read the ID card information and display it, then the ID card is not demagnetized. If the card reader is unable to read or the information read is incorrect, then the ID card may have been demagnetized. There are obvious scratches, wear or bending on the surface of the ID card, which may cause damage to the built-in chip and thus degaussing the ID card.
Verify whether the ID card is demagnetized, you can take the ID card to the nearby bank, hotel machine brush, check whether the information can be read normally, if yes, it indicates that the ID card has not been demagnetized, yesNormal use; If not, you need to apply for a new ID card. The first generation ID card has no magnetic field, and of course it cannot be eliminated.
Magnetic motivation is also completely feasible, there are many ways to achieve magnetic motivation, many people have been successful. But it does not belong to the "perpetual motion machine", it consumes magnetic force, and later the machine will stop and need to be magnetized. As more and more magnetic motors are being invented, it is expected that there will soon be a principle model or minicomputer on the market.
Liu Guangya! It's perfectly fine if you remove the permanent characterTo achieve! According to the law of conservation of energy, perpetual motion machines are impossible to produce. I am glad to answer the question of the subject, many scientific principles seem to be particularly profound, and I hope to be able to use the simplest language to describe the most scientific views. What is a perpetual motion machine? A perpetual motion machine is a machine that no longer needs external energy after giving it an initial energy but can keep moving.
No, there is an electromagnetic coil above a permanent magnet, then the potential energy generated by the electromagnetic coil with a quantitative work is proportional to the magnetic force of the permanent magnet. Perpetual motion machines are those that violate the fundamental laws of thermodynamicsCan achieve the engine. A machine that can always do work without consuming energy violates the first law of thermodynamics, so it is called "the first kind of perpetual motion machine".
Perpetual motion machine violates the fundamental laws of thermodynamics, so it cannot be realized. Energy is neither produced nor lost; it is merely transferred from one object to another, or from one form to another, and in the process of transformation or transfer, the total amount of energy remains constant. It is not possible to take heat from a single heat source and turn this heat completely into work without other effects.
According to current physics research, energyIt's conserved. Electricity is also a kind of energy, and if it is produced, other energy needs to be converted. The power of the magnet will slowly diminish, so there is no possibility of a perpetual motion machine at present.
Macroscopic perpetual motion machine can be realized. The debate about perpetual motion machines is not so simple. There are many great people in history who study perpetual motion machines, including Newton and Tesla. Now still in the study of perpetual motion machine, there is Tsinghua University doctoral supervisor Wei Fei. He is also the director of the State Key Laboratory, and the world's longest and most resilient carbon nanotubes are made by his team.