Why do science and technology students need to read the reasoning novels of dongye Qiwu?

Zheng Yi 20091119

Dongye often adds all kinds of knowledge points to his reasoning novels, so that you can enjoy his strict logical reasoning and get popular science. Two examples have been given above, such as the P/NP problem in "the dedication of the Suspect X", and the Monroe Effect in the predicate of the series "probe Galileo. Therefore, it is strongly recommended that science and technology students read the reasoning novels of dongqiawu and click here to package and download his 21 novels from Sina love question. The following is a few simple examples.

1. Heart death caused by ultrasonic cavitation Paralysis

The dead died of heart paralysis in the bathtub. On the right side of the body's chest, there was a mole about 10 centimeters in diameter, gray, and the cells were completely necrotic, the police felt that they were instantly destroyed.

Citation:

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"What kind of thing can we create with ultrasound ?"

"It depends on how it is used. You must have heard of the word "ultrasound therapy". If you make good use of it, it will be good for our bodies ."

"Will it become a weapon if it is improperly used ?"

"Yes ." Tang Chuan nodded,"When an ultrasonic wave is transmitted in water, negative pressure is generated, resulting in holes or bubbles in water. When the pressure changes from negative to positive, these holes will disappear and generate a strong and huge destructive power.. The processing of precious stones and super cemented carbide uses the power of ultrasonic ."

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"Is it so powerful ?"

"It's even scary ." Tang Chuan said, "ultrasonic therapy can be considered as a massage with a large number of compression times, but I have heard that it is extremely dangerous to have long-term treatment at the same location, if it is difficult to solve the problem, it may cause visceral perforation, and the nerves may also be paralyzed."

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"The trumpet is only as big as a hair dryer, connected to a power cord. There are also many power supplies, some of which are as big as a suitcase ."

Cao Yu once again admired this unknown man.

"So what else can I do after I put this horn on my chest ?"

"You just need to turn on the power ." Tang Chuan easily said,"When the bell mouth is close to the chest, a large number of bubbles will be generated vigorously, and they will be exposed to the victim's chest, so that the ultrasound will be carried between water, skin, body fluid at the same time, finally, it reaches the heart. The intense vibration eventually paralyzes the nerves of the heart.."

"In an instant !"

"It does not take too long ."

The grass shook his head and thought,This powerful method of killing was born..

"-- From dongye guiwu" exploring Galileo"

This principle should be applied to fully automatic dishwashers, ultrasonic cleaning machines, and Ultrasonic Therapeutic instruments:Ultrasonic cavitationAnd then go to the rootCavity principle (or the cavitation effect). This was a technology many years ago.

The general principle is that when the liquid emits a high-intensity ultrasonic longitudinal wave, the liquid produces a high-intensity dense area, which correspondingly produces positive and negative pressure. The negative pressure can split the liquid and the gap occurs. This is the so-calledUltrasonic cavitation. Ultrasonic cavitation can be traced back to the cavity phenomenon.

Cavity was first discovered in the early 20th century. At that time, 12 hours after the first trial of the sea giant wheel, it was found that the propeller was seriously damaged. Finally, engineers found that when the propeller rotates at high speed, a large number of tiny bubbles are generated,Although these bubbles are small, the pressure can reach thousands of atmospheres when they break down.. As a result, bubbles are continuously cracked, forming a shock or high-speed Micro-jet in the liquid. After such attacks, the layout of metal materials will be damaged.

[If this is the case, we have to ask a question,Since the high-speed rotation of the propeller will produce micro bubbles and damage the propeller, how do people solve this problem? Will this phenomenon limit the speed of ships? If bubbles are cracked, how can we reduce noise?

One tip is that the non-symmetric propeller produces fewer bubbles, and the other is that the blades generate more bubbles and I don't know any more.

If we are not responsible for gossip, since the water will produce the air erosion effect to limit the speed of the ship, we can think boldly and strengthen this effect, so thatWhen an object moves fast under water, a large bubble will be formed around it.Isn't it like an object flying underwater but flying in the air?

Is it possible ?!

Possible.

This effect is called the supercavitation effect (also translated by academic circles as superbubbles): supercavitation.

Engadget reported in September July that "super-air erosion effect submarine is finally coming true?", Jason also compiled the following:

"In fact, this phenomenon was discovered during World War II. The first to apply the phenomenon of ultra-air erosion to weapons was the German Herbert A in 1940. he developed two air-to-sea missiles: henschel HS 293 and henschel HS 294.

After the Second World War until 2004, only the former Soviet VA-111 Shkval torpedo publicly claimed to use the phenomenon of ultra-air erosion to achieve the goal of underwater high-speed travel. In 2004, barracuda, a torpedo known as underwater velocity of up to 800 km/h, also claimed to have used ultra-air erosion. However, till now, this phenomenon has not been successfully applied to a large-sized object such as a submarine (via1 via2 via3) "(Note: It can be translated as a bubble or an empty eclipse .)

Engadget boldly predicted that "The Battle of the future world will be carried by an aircraft carrier with dozens of small ultra-air erosion fighters, it takes several hundred kilometers per hour to fight in the sea! 』

This technology has been followed up in recent years.

Some people commented under the egg: "The Russian storm torpedo, to put it bluntly, is Yu leijia's rocket engine, and then air erosion occurs at high speeds. Apart from the tip of the torpedo, it has contact with water, it is surrounded by air. So the resistance is small and the speed is fast. However, this type of torpedo cannot be guided by a line, but it can only be used for melee because it cannot be controlled when it is launched. It seems that many countries are studying this thing. Iran has received Russian technology and has tested a nuclear torpedo. China seems to be developing .』

]

Back then, in 1927, wood (R. W. Wood) and lums (A. L. Loomis) first used high-power ultrasound. The blue-jet-type Z transducer is used in combination with high-power vacuum tube to generate high energy in the liquid, which causes the so-called cavity phenomenon.

There is an ultrasonic diet method that uses this method. Ultrasonic Waves generate alternating positive and negative pressures in each vibration cycle, so that the internal and external pressures of the fat cell membrane are not equal. When the cell membrane reaches the tolerance limit and is broken, fat cells are damaged.

Don't underestimate thisUltrasonic cavitationIt is not as simple as squeezing out the cell wall. If the ultrasound contrast agent is injected into the vein, a large amount of micro-bubble blood flow is formed. Bubbles produced by ultrasonic waves and micro bubbles can produce resonance and quenching under sound pressure. in a small space, high temperatures (> 1500 ℃) and high pressures (> thousands of pressure) may occur ), even with a powerful shock wave and a jet with a speed of up to 400 Mb/s, And the instantaneous discharge and glow process, orz.

Studies show that when the diagnosis of ultrasound fixed point irradiation early pregnancy uterus or the fetus itself more than a certain period of time, it will cause changes in the fluffy tissue or the fetal tissue, and more think, this change is dueUltrasoundNullInformatizationMechanism.

Of course, this mechanism is usually used as a surgical ultrasound knife. Because of the mechanical and cavitation properties of ultrasound, selective removal of human tissue can greatly reduce the amount of bleeding and speed up the operation, improve the surgical quality. This is also true for ultrasound crushing stones in the body.

2. magnet can suck soap bubbles

Citation:

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"Attracted by the magnet," Tang Chuan poured coffee powder into the cup and looked back at the grass. "It is not a detergent, but the air inside ."

"Air ?"

"To be precise, it is oxygen.Oxygen has a strong magnetism.. The so-called smoothing is the property that can be attracted by the magnet ."

"Ah ?" The grass-roots stare at the soap bubbles that haven't been burst on the tray.

"Sometimes human inertial thinking is terrible. Although people know that there is air in the soap bubble. But because our eyes cannot see it, we often forget its existence. As a result, many things in our lives are ignored ."

"-- From dongye guiwu" exploring Galileo"

I don't know if the sofa bubble like tocheon is filled with ordinary air and can be attracted by the magnet in tocheon's hand. This phenomenon requires two important points: one must be oxygen in a soap bubble, and the other must be a strong magnet, because liquids or gases have very weak effects on magnets.

If we fill the soap bubble with oxygen and place it in the middle of the strong electromagnet pole, then the soap bubble will be pulled by magnetic force and stretched out in the middle of the pole. The candle light placed in the middle of a strong magnet pole will change its normal shape and clearly tell us its sensitivity to magnetic force.

2. Lightning is used to import aluminum into the pond to form a vivid mask on the face of the corpse.

This phenomenon should be "Hydraulic molding" or "Electro-hydraulic forming" on the project ".

This is one of the "high-speed and high-energy forming" technologies.

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"The experts' opinion is that such a masterpiece can be formed only when the power is powerful and fully equal and continuously applied to the aluminum skin ."

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"In an instant, a huge shock wave is generated in the water. It has a force that pushes the object next to it outward. The aluminum sheet will naturally be pressed to the face of the model ."

"Is this the result ?" The grass looked at the metal mask and whispered.

"In the past, this was a well-known technology, but now almost no one has used it to create anything. I am also the first time doing such an experiment. I am really knowledgeable !"

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"Can I create that effect with a rifle ?"

"When a bullet is fired into the water, it can also form a shock wave, but to make the metal shape, use ~ Hand ~ The gun is far from enough. At least the rifle should be powerful ."

"Oh !" Cao Yu was a bit confused, but nodded with warmth. "What does it have to do with what we say today ?"

"The technology that produces golden braces is achieved by using the shock wave of bullets. This is the result of a University's research ."

"-- The above three paragraphs are from dongye qiawu," exploring Galileo"

Electro-hydraulic forming refers to the method of generating plastic deformation of the billet by using the high-energy shock wave generated during high-pressure discharge in the liquid medium. It uses the powerful shock current generated in the discharge circuit to expand the vapor near the electrode, thus generating a strong impact pressure and forming the metal billet. The energy control and adjustment during electro-hydraulic forming are simple, and the forming process is stable, safe, and low noise.

 

Now, we will introduce these. You are welcome to read the series of reasoning novels, or watch the Japanese opera "Detective Galileo ).

 

Zheng Yu, Beijing

 

 

 

Recommended reading:

Japanese drama discussion area: a brief analysis of scientific terms and physical phenomena in Galileo.