Chapter 85 Hate Unexplainable Things
Nuclear magnetic resonance imaging technology uses the hydrogen nucleus in human tissue to be stimulated by radio frequency pulses in the magnetic field to produce magnetic resonance signals. After electronic computer processing, it reconstructs the imaging technology of images at a certain level of the human body, which is an important milestone in the history of human medicine.
The magnetic field strength of this nuclear magnetic resonance imaging system imported by Concord Hospital is 1.5T, and the static magnetic field uses magnetoresistance technology, that is, resistive magnets. This is composed of many coils around the cylinder.
is similar to the principle of electromagnets. After these coils are energized, a magnetic field can be generated. If the power is cut off, the magnetic field will disappear. Compared with superconducting magnets, although the cost of this magnet is low, it consumes a lot of electrical energy to operate, because there is an inherent resistance in the wire.
In general, these coil wires will not burn out, because this has been taken into account in the design and can withstand a relatively large current impact.
But the machine in front of Harris has burned to pieces!
He can't imagine how much current it is to burn these coils like this.
The technician tested this and found that the burn was not caused by a short circuit at all.
What makes them feel very strange is that except for this machine, there is no problem with the other circuits of Concord Hospital. Technically, it doesn't make sense at all. Because there is only one possibility to cause this situation, that is, another stronger magnetic field than this machine suddenly explodes inside the machine, which generates a super-large current due to the super-superposition of magnetic field and electromagnetic effects at that moment, thus burning the circuit.
However, this is obviously impossible.
The unit of magnetic field strength can be expressed by Gauss and Tesla. 1 Tesla is equivalent to 10,000 Gauss. Compared with the magnetic field of 0.5 Gauss on Earth, the magnetic field strength of 1.5 Tesla is already very amazing.
Therefore, when the patient is examined, it is forbidden to carry any metal or magnetic items on the body. If a metal object is brought into the scanning room, it may become a dangerous emitter and fly out.
For example, pins, pens, keys, scissors, etc. may be suddenly pulled out of the pocket and fly to the opening of the magnetic field at a high speed after leaving the body, which will pose a threat to the safety of everyone in the room.
In addition, the information in credit cards, bank cards and other magnetic encoded devices will also be magnetically erased.
Harris carefully asked the hospital staff, and all operations were carried out in accordance with the corresponding regulations. When a patient was normally checked, the machine suddenly had a problem.
This situation is very rare, and Harris has never seen such a case before.
"I hate everything that can't be explained!" Harris muttered, "Is it the patient who emitted a strong magnetic field that caused the machine to burn?"
An idea came to his mind that made him feel strange.
Then he shook his head with a wry smile: "Unless he is Clark_Kent."
Harris's Clark_Kent is a famous American comic character. He also has a popular name called Superman.
Harris carefully photographed all the details of the scene with a camera, and had to report the matter to the headquarters later. To this extent, the repair was useless. It can only be replaced, but it requires the headquarters to nod. He has to write a detailed technical report for this, send the situation back truthfully, and finally let the headquarters determine whether it is a product quality problem and replace it for free.
Lin Hong continued to play two games, Genesis and Karate.
In fact, these two games are not as good as those large arcade games in terms of graphics, sound effects, and fun. But because this is the first game he played on the computer, he is also very happy.
After clearing the two games separately again, he felt that it was not very interesting.
So he took out the red book and read it again.
He directly skipped the previous content about the basic operation and the introduction of BASIC, focusing on the firmware and hardware parts that he only slightly scanned before.
The content of this part is closely related to the hardware. In fact, for Lin Hong, it is easier to accept than the previous content, because the content he previously contacted was all about electronic hardware.
But he was eager to operate the computer before, so the latter part was just slightly scanned and put down, leaving it for careful reading later.
The wordfirmware is translated from English, and the word is FIREWARE.
It is also a kind of software, but this kind of software does not require users to install and modify it in the operating system. 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 to make some simple settings for the motherboard. For example, the motherboard clock, the frequency modification of the CPU, the system startup media order, etc.
In addition, more complex hardware such as displays, floppy drives, and hard disks also have their own firmware, but these firmwares usually do not require user contact, so they are rarely known.
The firmware has been burned into the hardware storage ROM when it left the factory, and there will never be a problem. For example, if there is a problem with the motherboard clock, just remove the battery on the motherboard and reset it.
It is the software responsible for dealing directly with the hardware, just like a low-level small language translator. If other software wants to control the hardware, it must be translated through it, otherwise the two sides can't understand the language, because the hardware, an indigenous person, can only understand the small language dialect belonging to its own tribe.
Due to this period, the history of computers is not long, especially the APPLE_II personal computer, which is basically the first successfully commercialized 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, even all of which he drew by himself, are 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 all computer manuals were like this. At this moment, he is completely immersed in the ocean of firmware and hardware knowledge.
In order to impress himself, he even removed the monitor from the chassis. According to the instructions, he opened the cover on the keyboard and directly exposed the motherboard and various component circuits inside.
The integrated design of the keyboard and chassis is also Wozniak's masterpiece. In order to enable users to easily expand the functions of the computer, he has designed up to eight expansion slots for APPLE_II, so that users can plug in a variety of function cards on it to improve the computer. The performance.
Lin Hong feels very familiar with some of the circuits on the motherboard. He has seen a similar circuit structure in Dongling Game Hall before. The arcade game motherboard is very similar to the circuit board of this computer in some places.
Lin Hong is very happy about this, and he also hates unexplained things.
And this time I finally have the opportunity to understand the basic principles of these circuits, because these circuits are detailed in the manual, and even interspersed with the design concepts of some designers, why it is designed like this, what are the benefits of this design, etc.
He couldn't help sighing that this book is simply a computer production manual.
When Feng Wan came home, it was almost five o'clock. By the way, she also bought Lin Hong's desk and specially asked someone to move directly to Lin Hong's bedroom.
She didn't go grocery shopping today, because she had agreed to Roy Cook's invitation yesterday to go to the Friendship Hotel for dinner with him in the evening.
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