In the past, people didn't have radar when fighting, and they were always ambushed by planes when they were not ready. Scientists have studied bats for a long time and found that bats have poor eyesight, but they can accurately catch their prey at night. Why? It turns out that every bat can emit an "ultrasonic wave" in its mouth, and this wave will reflect back when it meets an object. The bat's ears are like "receivers", judging whether they are rocks or prey according to the received signals.

Scientists invented radar according to this principle. Radar can also send out ultrasonic waves and bounce back when it touches an airplane, so that it can predict whether the enemy is coming to sneak attack.

2. Flies and Spaceships

Annoying flies seem to have nothing to do with the grand space cause, but bionics closely links them.

Flies are notorious "stinkers", and they are found everywhere that smells foul. Flies have a particularly sensitive sense of smell, and they can smell smells thousands of meters away. But the fly does not have a "nose". What does it rely on to act as a sense of smell? It turns out that the "nose" of flies-olfactory receptors are distributed on a pair of antennae on the head.

Each "nose" has only one "nostril" communicating with the outside world, which contains hundreds of olfactory nerve cells. If odor enters the nostrils, these nerves immediately convert the odor stimulus into nerve electrical impulses and send them to the brain. The brain can distinguish substances with different smells according to the different nerve electrical impulses generated by substances with different smells. Therefore, the fly's antenna is like a sensitive gas analyzer.

Inspired by this, bionics successfully imitated a very strange small gas analyzer according to the structure and function of fly olfactory organ. The probe of this instrument is not a metal, but a live fly.

A very fine microelectrode is inserted into the olfactory nerve of a fly, and the guided neuroelectric signal is amplified by an electronic circuit and sent to an analyzer; The analyzer can give an alarm as soon as it finds the signal of the odorous substance. This instrument has been installed in the cockpit of the spacecraft to detect the composition of the gas in the cabin.

This small gas analyzer can also measure harmful gases in submarines and mines. This principle can also be used to improve the input device of computer and the structural principle of gas chromatography analyzer.

3. From fireflies to artificial luminescence

Since man invented the electric light, life has become much more convenient and rich. But electric lamps can only convert a small part of electric energy into visible light, and most of the rest are wasted in the form of heat energy, and the heat rays of electric lamps are harmful to people's eyes. So, is there a light source that only emits light without heating? Humans have turned their attention to nature again.

In nature, many creatures can emit light, such as bacteria, fungi, worms, mollusks, crustaceans, insects and fish, and the light emitted by these animals does not produce heat, so it is also called "cold light".

Among many luminous animals, fireflies are one of them. There are about 1 500 species of fireflies, and their luminescent colors are yellow-green, orange, and their brightness is also different. Fireflies emit cold light, which not only has high luminous efficiency, but also is generally soft and suitable for human eyes, and the intensity of light is relatively high. Therefore, bioluminescence is an ideal light for human beings.

Scientists have found that the luminous device of fireflies is located in the abdomen. This light emitter consists of three parts: a light emitting layer, a transparent layer and a reflecting layer. The luminescent layer has thousands of luminescent cells, all of which contain fluorescein and luciferase. Under the action of luciferase, fluorescein, with the participation of intracellular water, combines with oxidation to emit fluorescence. The luminescence of fireflies is essentially a process of converting chemical energy into light energy.

As early as 1940s, people created fluorescent lamps based on the study of fireflies, which greatly changed the lighting sources of human beings. In recent years, scientists first isolated pure fluorescein from fireflies, then isolated luciferase, and then synthesized fluorescein artificially by chemical methods.

A biological light source composed of fluorescein, luciferase, ATP (adenosine triphosphate) and water can be used as a flash lamp in a mine full of explosive gas. Because this kind of light has no power supply and will not produce magnetic field, it can be used to clear magnetic mines under the illumination of biological light source.

Now, people can get cold light similar to biological light by mixing some chemicals for safe lighting.

4. the windward ears of jellyfish

"Swallows fly low to rain, cicadas sing and the sky clears up in the rain." The behavior of living things has something to do with the change of weather. Fishermen along the coast know that the fish and jellyfish living along the coast swim to the sea in batches, which indicates that the storm is coming.

Jellyfish, also called jellyfish, is an ancient coelenterate, which floated in the ocean as early as 500 million years ago. This kind of inferior animal has the instinct to predict storms, and every time before storm warning, it swims to the sea to take refuge.

It turns out that in the blue ocean, infrasound (frequency is 8-13 times per second) generated by the friction between air and waves is always the prelude of storm warning. This infrasound can't be heard by human ears, but the little jellyfish is very sensitive. Biomimetics found that there is a thin handle in the cavity of the jellyfish's ear, and there is a small ball on the handle, and there is a small auditory stone in the ball. When the infrasound before the storm hits the auditory stone in the jellyfish's ear, the auditory stone stimulates the nerve receptors on the ball wall, so the jellyfish hears the rumble of the coming storm.

Bionics imitates the structure and function of jellyfish ears, and designs a storm predictor for jellyfish ears, which accurately simulates the organs of jellyfish that feel infrasound on the transportation shaking table. When this instrument is installed on the front deck of a ship, when it receives the infrasound wave of the storm, it can make the horn rotating 360 stop rotating automatically, and the direction it refers to is the direction of the storm. The reading on the indicator can tell the strength of the storm.

This predictor can forecast the storm 15 hours in advance, which is of great significance to the safety of navigation and fishery.

5. Squid and torpedo bait?

The capsule in the squid can secrete black liquid, and when it is in danger, it will release this black liquid to trick the attacker into falling for it. Submarine designers imitated this function of squid and readers designed torpedo bait.

Torpedo lure vinegar is like a pocket submarine, which can sail according to the original course of the submarine with the same speed, and can also simulate the noise, spiral beat, sound signal and Doppler tone change of the transportation shaking table. It is this vivid performance that makes it difficult to tell whether the enemy submarine or the torpedo under attack is true or false, and finally makes the submarine escape.