Magnetic resonance imaging technology uses the hydrogen nuclei in human tissues to be excited by radiofrequency pulses in the magnetic field to produce magnetic resonance signals, and reconstruct the image of a certain level of the human body through electronic computer processing, which is an important milestone in the history of human medicine.

The magnetic field strength of the MRI system imported from Union Medical College Hospital is 1.5t, and the static magnetic field uses magnetoresistive technology, that is, resistive magnets. This is made up of a lot of energized coils around a cylinder.

Similar to the principle of electromagnets, when these coils are energized, a magnetic field can be generated. If the power is lost, the magnetic field disappears. Although less expensive than superconducting magnets, they require a lot of electrical energy to operate because of the inherent resistance in the wires.

In general, these coil wires will not burn out, because they have been designed with this in mind, and can withstand relatively large current shocks.

But the machine in front of Harris was burned to the ground!

He couldn't imagine how much current it would take to burn these coils like this.

Technicians tested this and found that it was not burned out due to a short circuit in the circuit at all.

What made them feel very strange was that apart from this machine, there was no problem with the other circuits of Union Hospital, which was technically unreasonable. Because there is only one possibility that this can cause this, and that is that there is another magnetic field stronger than this machine that suddenly explodes inside the machine, which at that moment generates a large current due to the superposition of the magnetic field and the electromagnetic effect, which burns the circuit.

However, this is clearly not possible.

The units of magnetic field strength can be expressed in Gaussian and Tesla. 1 Tesla is equivalent to 10,000 Gauss, and the strength of the magnetic field of 1.5 Tesla is already very amazing compared to the Earth's magnetic field of 0.5 Gauss.

Therefore, it is forbidden to bring any metal or magnetic objects on the patient's body during the examination. Metal objects that are brought into the scanning chamber can turn into dangerous projectiles and fly out.

For example, paper clips, pens, keys, scissors, etc., can suddenly be pulled out of their pockets and fly at very high speeds towards the opening of the magnetic field after being detached from the body, which poses a threat to the safety of everyone in the room.

In addition, information in credit cards, bank cards, and other magnetically encoded devices is also magnetically erased.

Harris spoke carefully to the hospital staff, and everything was done according to the regulations, and when a patient was doing a normal examination, the machine suddenly went wrong.

This is very rare, and Harris has never seen such a case before.

"I hate not being able to do everything that can't be explained!" Harris muttered, "Could it be that the patient emitted a strong magnetic field that caused the machine to burn down?" ”

A thought popped up in his head that even he couldn't even think.

Immediately after, he shook his head with a wry smile: "Unless he is clark_kent." ”

The clark_kent in Harris's mouth is a famous American comic book character, and he also has a more popular name called Superman.

Harris carefully filmed all the details of the scene with his camera, and then had to report the matter to headquarters, and the damage was so bad that repairs were useless. Only replacement, but this requires the nod of the headquarters, he has to write a detailed technical report for this, and send the situation back truthfully, and finally let the headquarters determine whether it is a product quality problem and give a free replacement.

Lin Hong continued to play two games, "Genesis" and "Karate".

In fact, neither game can compare to the big arcade games in terms of graphics, sound effects, and fun. But since it was the first time he played the game on his computer, he also had a lot of fun.

After beating the two games separately again, he didn't feel much fun.

So he took out the red book and re-read it.

He skipped the previous content about basic operations and basic introductions, focusing on the firmware and hardware parts that he had only slightly scanned before.

The content of this part is closely related to hardware, in fact, it is easier for Lin Hong to accept than the previous content, because the content he was exposed to before was all about electronic hardware.

But he was in a hurry to operate the computer before, so the latter part was only slightly scanned and put down, leaving it to be read carefully later.

The word firmware is translated from English, and the word is fireware.

It is also a kind of software, which is nothing more than this kind of software in the operating system, and does not require the user to install and modify it, it is solidified in the hardware chip, leaving only specific commands to operate on it.

The most common firmware is the BIOS of the motherboard, generally when the operating system starts, you can enter the system by pressing a specific key, and make some relatively simple settings for the motherboard. For example, motherboard clock, CPU frequency modification, system boot media order, etc.

In addition, more complex hardware such as monitors, floppy drives, and hard disks also have their own firmware, but these firmware usually do not require user contact, so they are rarely known.

The firmware has been burned into the storage ROM of the hardware when it leaves the factory, and there will never be a problem, for example, if there is a problem with the motherboard clock, you can deduct the battery on the motherboard and reset it.

It is the software responsible for directly dealing with the hardware, just like a translator of a small language at the bottom, and other software must translate through it if they want to control the hardware, otherwise the two sides will not understand the language, because the hardware can only understand the dialect of the small language belonging to their own tribe.

Since the history of computers in this period was not very long, especially apple_ii personal computer, which was basically the first successful commercial microcomputer, so all these codes were written by its inventor, Wozniak.

He published all the important functions and codes in this manual, and the hardware circuit diagrams in it were even hand-drawn by him, which was incomparably detailed.

That's why Apple fans around the world call this Red Book the "Bible."

Of course, Lin Hong didn't feel this, he thought that all computer manuals were like this. He is now completely immersed in a sea of firmware and hardware knowledge.

In order to deepen his impression, he even moved the monitor off the chassis and, according to the instructions, opened the lid on the keyboard, directly revealing the motherboard and various component circuits inside.

The integrated keyboard and chassis design is also Wozniak's masterpiece, and he designed up to eight expansion slots for the apple_ii in order to allow users to easily expand the functions of the computer themselves, so that users can insert a variety of function cards on it to improve the performance of the computer.

Some of the circuits on the motherboard Lin Hong felt very familiar, he had seen similar circuit structures in the Tanglin City Game Hall before, and the arcade game motherboard was very similar to the circuit board of this computer in some places.

Lin Hong was very happy about this, and he also hated things that could not be explained.

And this time I finally had the opportunity to understand the basic principles of these circuits, because these circuits are explained in detail in the manual, and even interspersed with some design ideas of the designer, why they are designed this way, what are the benefits of such a design, etc.

He couldn't help but sigh that this book was like a manual for making a computer.

When Feng Wan went home, it was almost five o'clock, and she also bought Lin Hong's desk by the way, and specially asked someone to move directly to Lin Hong's bedroom.

She didn't go grocery shopping today, because yesterday she had agreed to Roy Cook's invitation to have dinner with him at the Friendship Hotel in the evening.

Seek demons