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  Magnetic Resonance Imaging (MRI) technology utilizes the phenomenon of nuclear magnetic resonance that occurs when hydrogen nuclei in the body's tissues are excited by radiofrequency pulses in a magnetic field, producing magnetic resonance signals. These signals are then processed by computer to reconstruct images of specific planes of the body, representing an important milestone in the history of human medicine.

  The imported nuclear magnetic resonance imaging system of Concord Hospital has a magnetic field strength of 1.5T, and the static magnetic field uses magnetoresistive technology, that is, resistive magnets, which are composed of many energized coils around the cylindrical body.

  Similar to the principle of electromagnets, these coils can generate a magnetic field after being energized. If the power is cut off, the magnetic field will disappear. Compared with superconducting magnets, this type of magnet has a lower cost but requires a large amount of electric energy to operate because there is inherent electrical resistance in the wire.

  In general, these coil wires will not burn out because they have been designed to withstand relatively large current surges.

  But the machine in front of Harris was already burnt beyond recognition!

  He really couldn't imagine what kind of current could burn these coils into this state.

  Technicians tested it and found that the burn was not caused by a short circuit.

  What they found strange was that, apart from this machine, all the other circuits in Concord Hospital were perfectly fine, which didn't make any sense technically. Because there's only one possibility that could cause such a situation - another magnetic field stronger than this machine suddenly burst inside the machine, causing an ultra-large current to be generated due to the superposition of the magnetic fields and electromagnetic effects at that instant, burning out the circuit.

  But this is obviously impossible.

  The unit of magnetic field strength can be expressed in Gauss and Tesla. 1 Tesla is equivalent to 10,000 Gauss, and relative to the Earth's 0.5 Gauss magnetic field, a magnetic field strength of 1.5 Tesla is already quite astonishing.

  So when the patient is undergoing examination, it is forbidden to carry any metal or magnetic objects on the body. If a metal object is brought into the scanning room, it may become a dangerous projectile and fly out.

  For example, hairpins, pens, keys, scissors, etc. may be suddenly pulled out of the pocket and will fly towards the opening of the magnetic field at a very high speed after leaving the body, which poses a threat to the safety of all people in the room.

  In addition, information on credit cards, bank cards and other magnetic stripe devices can also be erased by magnetism.

  Harris inquired with the hospital staff and everything was done according to regulations, when a patient was undergoing a normal examination, the machine suddenly malfunctioned.

  This is extremely rare and Harris had never seen a case like this before.

  "I hate things that can't be explained!" Harris muttered, "Was it the patient who emitted a strong magnetic field and caused the machine to burn out?"

  Harris carefully photographed all the details of the scene with a camera, and then he had to report this matter back to headquarters. The damage was so severe that repairs were useless. Replacement is the only option, but it needs to be approved by headquarters. He has to write a detailed technical report and send the situation back as it is, ultimately letting headquarters decide whether it's a product quality issue and provide free replacement.

  Lin Hong continued playing "Genesis" and "Karate".

  In fact, these two games are not as good as those large-scale arcade games in terms of graphics, sound effects, or fun. However, since this was his first time playing a game on a computer, he also played very happily.

  After passing these two games again, he felt that it was not very interesting.

  Then he took out the little red book and began to read it again.

  He skipped over the basic operations and introductory content at the beginning and focused on the firmware and hardware parts that he had only briefly glanced at before.

  The content of this part is closely related to the hardware, and it's actually easier for Lin Hong to accept than the previous content, because he was previously in contact with electronic hardware.

  But before he was in a hurry to operate the computer, so the latter part just glanced at it lightly and put it down, leaving it for later careful consideration.

  The term "firmware" is a loanword from English, with the word being "firmware".

  It is also a kind of software, but this kind of software does not exist in the operating system, nor does it need to be installed and modified by users. It is solidified on the chip of hardware, leaving only specific commands that can operate on it.

  The most common firmware is the BIOS of the motherboard, which can be entered by pressing a specific key when the operating system starts, and some simple settings can be made for the motherboard, such as the motherboard clock, CPU frequency modification, boot media order, etc.

  In addition, hardware such as monitors, floppy drives and hard disks also have their own firmware, but this firmware usually does not require user interaction, so it is rarely known.

  Firmware is already burned into the hardware's storage RO at the time of shipment and will never have problems, for example, if there is a problem with the motherboard clock, simply remove the battery from the motherboard to discharge and reset it.

  It is the software responsible for directly interacting with hardware, just like a lowest-level translator, and other software must go through it to control hardware, otherwise they do not speak the same language because the hardware can only understand its own dialect.

  Because of this time, the history of computers is not long, especially Apple II personal computer, basically considered to be the first successful commercialized microcomputer, so these codes were written by its inventor Wozniak.

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

  This is also why Apple fans all over the world call this red book "Bible".

  Of course, Lin Hong did not feel anything about it. He thought all computer manuals were like this. At this moment, he had already been deeply immersed in the ocean of firmware and hardware knowledge.

  In order to deepen his impression, he even moved the monitor down from the case, opened the cover on the keyboard according to the instructions, and directly exposed the motherboard and various component circuits inside.

  The all-in-one design of the keyboard and casing was also Wozniak's masterpiece, he designed as many as eight expansion slots for Apple II in order to allow users to easily expand the computer's capabilities by themselves, so that users can plug various functional cards into it to improve the performance of the computer.

  Some of the circuits on the motherboard looked familiar to Lin Hong, he had seen similar circuit constructions in the arcade game hall in Dongling City before, and the main board of the arcade game was very similar to the circuit board of this computer in some places.

  Lin Hong was extremely delighted about this, and he also hated things that couldn't be explained.

  This time, I finally have the opportunity to understand the basic principles of these circuits, because the manual has detailed explanations of these circuits, and even interspersed with some designers' design concepts, why they were designed this way, what are the benefits of designing this way, etc.

  He couldn't help but feel that this book was a manual for making computers.

  Feng Wan returned home, it was almost five o'clock. She also bought Lin Hong's desk and had someone move it directly to Lin Hong's bedroom.

  She didn't go shopping today because she had promised Roy Cook yesterday to have dinner with him at the Friendship Hotel tonight.

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