To know that uranium element, and uranium-235 do not mean the same thing.

Uranium, as a chemical element, belongs to the actinide family in the periodic table with the chemical symbol U and atomic number 92. Because uranium is microradioactive, its isotopes are unstable, resulting in it in three forms in nature, namely uranium-238, uranium-235, and uranium-234.

And in these three forms, only uranium-235 can carry out spontaneous fission, in other words, only uranium-235 can really become a raw material for nuclear weapons.

And how much is uranium-235?

Compared with the content of uranium-238, 99.2739% to 99.2752% and uranium-235, it is only about 0.7198% to 0.7202%.

In other words, less than 0.1%, less than one in a thousand.

This is also the most difficult thing in the nuclear weapons research and manufacturing program - how to separate uranium-235 and uranium-238 and extract them specifically?

The current purification is purification in the true sense of the word, and it is the real operation of the nuclear raw material uranium-235, not its brother uranium-238.

You must know that uranium-235 and uranium-238 are isotopes, the physical and chemical properties are almost identical, the only difference may be that one has 143 neutrons in the nucleus, and the other has 146 neutrons.

How to use this distinction that only exists in the microscopic world to separate and purify uranium-235 is a real difficulty to be dealt with in the fourth stage of the nuclear weapons research and manufacturing program.

So, what to do?

Richard thought as he stood in the uranium purification sector, his eyebrows furrowed slightly, as if trying to recall the memories stored in his brain.

After recalling for a long time, his eyebrows slowly opened again, and he said with some relief: "Well, it seems that I forgot." ”

Yes, he forgot.

At the most critical stage of the plan, he forgot how to do it.

After all, his brain is not a computer, it is impossible to remember everything, and knowledge that is basically impossible to use such as nuclear weapons is easy to forget.

But after forgetting, he didn't have any panic or anger.

On the one hand, although he can't remember the knowledge of the fourth stage, he has a complete knowledge system, so he can deduce it through calculations, but it will only take a while.

On the other hand, he doesn't even need to deduce. Because now what he said is forgetting, not really forgetting, but the shallow brain activity is temporarily undetectable - after all, this knowledge is really not very useful in ordinary times, in order to ensure the most efficient use of the brain, he usually hides these relatively low utilization rate of knowledge, hides it in the depths of the brain, and puts the knowledge with higher utilization rate in the shallow layer of the brain to ensure that it can be retrieved as quickly as possible.

So......

"Breathe—breathe—"

Richard took a deep breath and said, "Looks like I'm going to go to that place." ”

"Well, let's go. Richard said, stepping out of the uranium processing sector and towards the main laboratory.

In the center of the Garden of Eden, in the cylindrical main laboratory, there is a separate lounge.

The lounge is small, only about four square meters, and the décor is very simple, except for a bed, there is almost nothing else.

This lounge has been rarely used since the main laboratory was built, but today Richard walked in.

......

"Click......

With a step, Richard walked into the lounge and didn't do anything special, just lay quietly on the bed.

"Breathe—breathe—"

"Breathe ———— inhale ————"

Richard kept breathing, getting lower and lower and intervals. The heart rate slows down, and the whole person enters a state of dormancy.

This state, more devotion than meditation, allowed Richard to access the deepest part of his brain and mobilize all his memories.

......

"Boom ......"

Unaware of where the roar came from, Richard's consciousness woke up in a starry sky.

Looking around, Richard noticed that he was surrounded by stars, large and small, and of different colors.

And the place where he is a void space, that is, in the barren outer space.

There is no air here, and naturally there is no air pressure, it is an absolute vacuum.

This is extremely dangerous for a fragile creature like humans.

According to the information collected in the leakage of a vacuum cabin spacesuit at the manned spacecraft center of a large country with the prefix N, it will not be seriously harmed at first.

For example, the human body does not explode because the skin has a certain elasticity.

The blood also does not boil.

Because human blood vessels also have a certain elasticity, they can produce a certain pressure on the blood, resulting in human blood pressure is generally higher than the pressure of the external environment by more than 75 Torr (1 Torr, equal to 1 mm Hg). When the environmental pressure in outer space is 0, the human blood pressure can be maintained at about 75 Torr, which is 75 mm Hg, or 0.099 standard atmospheres (760 mm Hg).

At this time, the boiling point of water is 46°C, and the human body temperature of 37°C is not enough for blood to boil.

People don't freeze to death.

Because space is not a cold place, in fact, because there are few molecules in space, space does not have the property of "temperature". In other words, it is neither cold nor hot and is a good insulator. When exposed to it, the water on the surface of the human body will evaporate, making people feel a little cold, but it will not freeze.

In short, exposure for a few seconds in a vacuum is not very bad.

But ten seconds later, the problem came.

For example, because the radiation of the star is too strong, there is no need for protection, which can lead to sunburn.

For example, although the skin is elastic, decompression sickness will occur because of the difference in air pressure between the body and the outside, resulting in mild, reversible, painless swelling of the skin and subcutaneous tissues.

At this time, the human consciousness can be maintained for about a few seconds, after which it will become paralyzed, convulsed, and unconscious.

During this process, water vapor forms in the soft tissues and veins, causing the body to swell to almost double its size. After that, the heart rises first, then decreases rapidly, and the arterial blood pressure also decreases. Venous blood pressure rises due to gas expansion, exceeding arterial blood pressure within tens of seconds, interrupting blood circulation within the body.

After a minute, the human body is very likely to die due to the tremor of the heart muscle fibers, and CPR cannot be reversed.

After two minutes, there is little chance of survival.

However, Richard was in outer space at this time, observing the surrounding environment for a long time, his expression was natural, and there were no injuries.

Because this is not the real world, or the material world of the outside world.

This is the virtual world, the world of imagination, the world of thinking, the world of Richard's brain, the bottom of his soul.

This is Richard's biggest secret, the reason why he left the Blue Lion Kingdom and came step by step to the present. It is the confidence to ignore all kinds of dangers, the source of endless hole cards, and the basis for trying to solve the ultimate problem.

Here, that's ...... Richard's Palace of Memory.