Spring is a kind of flexibility to work in the use of mechanical parts. Usually made of spring steel. To control the mechanical movement, easing impact or vibration, conservation of energy, the size of the measuring force, widely used in machinery, instrument. According to the shape, the main spiral spring, scroll spring, plate spring.
Most materials have different levels of flexibility, if the bending, with great power will be restored to its original shape. In the history of mankind, some early attention to seedlings and saplings branches is very flexible, because many of the original culture by using the property, in a special door or cage wedge on a stick, or with a noose in a pole to drop; upon release of tension, the stick or rod will rebound. They use this way to catch birds and animals. In fact, the bow is in this manner using elastic spring trees; the first backward bow, and then let go, let the springback. During the middle ages, the idea began to appear in the machinery, such as textile machine, lathe, drilling machine, milling machine and sawing. By hand or foot pedals are pressing stroke operator, will pull down machine, then use the rope fixed a pole bounced in machinery, reciprocating motion.
Torsional elastic materials not pressure on its flex resistance. The time period of the Greek Empire (around fourth Century BC) the invention of the torsion spring with twisted hair tendon rope or rope, spring to replace the simple to strengthen catapults and trebuchets power. When people start to realize greater than wood, metal, or any of the horny organic material elasticity. Philo (the writing age of about 200 BC) as a new found to be introduced. He estimated the reader is be hardly worthy of belief. The Boston Celtics and the sword of the elastic, caused his Alexander senior's attention. In order to make clear the sword why are flexible, they made many experiments. The results of his master Kete Xi than invented the trebuchet, spring machinery is a bronze plate bending into the spring -- is actually the earliest; the philotic I further improved these trebuchet. Creative Kete Xi than in the invention of the trebuchet, came up with a flexible work another trebuchet - it uses cylinder air under pressure.
In the future people will think: if the compression of a screw rod, instead of bending of a straight bar, then the metal spring stored energy will be more. According to Bo Runje Les Ki's biography records, he made a alarm, which uses several generation of spring. Someone recently pointed out, there is the alarm clock pattern in a mechanical manual with some peculiar spiral spring watches chart at the end of the fifteenth Century. This kind of spring is also used to trap the modern. The band spring (horizontal compression rather than vertical compression spring) clock, in about 1460 would have been used, but basically is the Royal luxury, for about 1 centuries, watches with spring became a symbol of middle class people.
Control the flow direction valve
As the valve only allows water or other fluid (such as air) flow in one direction, almost certainly, it first appeared as a member of early tools need this kind of movement -- the bellows. Agricola Renaissance in the metallurgy of the article said, wrought iron furnace bellows plates with a slightly longer and wider than the eye, "plate covered with goatskin, is tied with a belt board, flash red side of the ground". Placed way is: when the drum up bellows, sheet open; when the contraction, sheet off." Valve must be much more than Agricola's age is early, with wedge bellows as old. But it came out years it is difficult to determine, because the term flapper valve from the old leather bellows (in this kind of bellows, the operation can use hand or foot to block the eye). Obviously, the first model is about the era of the Greek Dynasty bronze lamp, but the late poet in Rome before Osuni have not been mentioned bronze light valve. Austrian Sony was the fast die on land the fish gills. To the skim wood cavity reciprocating motion through the hole alternately into the wind and wind wool valve.
Can say, the pressure pump mechanical valve's history began in Kete Xi than the. Wit Law Weiss and Hero made a detailed description of the pressure pump, they said: "smart security within the pipe outlet of annular sheets, will not let the pressure into the container and then things run back." It seems Kete Xi than the original flap valve pressure pump is long cylindrical, that was used to carry out roof ventilation. Rectangular valve was switched, but the name remains unchanged. Rome had been repaired several pressure pump, the valve has severe corrosion, but still recognizable. Herron as spoke of the double-cylinder pressure pump fire extinguishers, also introduced a primitive beat valve, some slide down in the three curved pillar small disc. Kete Xi than hydraulic mechanical slide valve is used to control the air into the pipe. In addition, during the Renaissance, the pump and the valve are all valve (or hinge valve).
Da Finch invented a cone-shaped tongue beating the door, no doubt Ramelli mechanical invention manual
(1588) the tongue door sources in the painting. With a contemporary of Ramelli Al Ody, a butterfly valve to control the pipe flow used in automatic puppets. However, the invention of the steam engine from Herron times until, the tongue beating the door without a widely used in all kinds of valves, did not change. The steam engine (need on the inflow and outflow of more precise control sequence) led to the precision valve associated with the engine's appearance, these valves, including the release of savings Newcomen design of air in the cylinder of the "jet valve", Murdoch slide valve (1799) and the double-acting piston engine to maintain balance valve the.

 The steam engine.
In ninth Century a hymn once talked about western crank and crank pin and crank arm connected to rotate the millstone. After 500 years, only occasionally found in the legend of crankshaft. Shortly after the 1400 ad, at least with rotary lift cage, the low countries, even test instrument illustrated manuscripts seemed suddenly appeared crankshaft. Combined crankshaft appeared at the same time, initially for the draw, is a hand tool simple. However, in the rod crankshaft first appeared after a few years, some people think of crank arm rotating rod can be used to replace the hand connecting rod, connecting rod mill, is only the extension of the arm, however, the connection mechanism can reverse movement, to operate a pump by rotating the crank drive linkage, as described in the 1431 a manuscript. Therefore, the crankshaft was born. In fifteenth Century and sixteenth Century generally uses the crank to drive the bellows and large sawing machine, they are two kinds of machines only require bidirectional control. Occasionally the crankshaft in a pump, but has designed or even four crank shaft, and may well be installed everywhere use. However, for a long time, people don't really welcome crankshaft, because as long as the heavy machines are made of wood, the crankshaft is not easy to form a whole, will make the connection by a lot of stress.
Anyway, in the iron age, has not received due credit for crankshaft. In 1780, Watt found himself was a patent restrictions, can not use his steam engine crankshaft reciprocating motion into rotary movement -- the old path of motion reversal. Although he is very angry, but from the inspired, designed to stellar and planetary gear with a purpose. But with the outdated patent, the crankshaft into the standard equipment for this job. If you use two or more cylinders, or must provide power from both sides (for example to provide power to the paddle wheel steamer.), then, the crankshaft is a solution. In the age of steam and then, crankshaft is used in piston engine for all of twentieth Century, no matter what kind of fuel could drive.
Screw and screwdriver.
Mu Luosi (in the United States are sometimes called screw) is relatively recent. However, in sixteenth Century, gunsmith and armourer already use a belt lug small tool -- the "screwdriver" -- to regulate their rifle mechanism. Rifle mechanism with a nail in the butt. It was found, with thread on the nail, will be fixed more firmly. Like all other nails, they are knocked into, out of difficult. The only solution, before will nail type, cut grooves in the head. So, using the "screwdriver" can remove them. So, the screwdriver became the earliest screw pliers or loosening device. Feilibian 1676 screwdriver is this type.
As the screw is handmade, natural expensive cost, only in special workpiece. However, by the end of the eighteenth Century, some not well-known genius (probably in the UK Bermingham) found a way to create a better, but still is the manufacture of flat end screw machine. This makes the screw has the advantages of low cost, can be widely used for the fixed hinge, door, furniture etc.. However, fine thread screw effect and reduce the tapping, use longer lug tool to screw on the inside. Around the 1780 ad, the London assembly tool manufacturers introduced a long screwdriver screwdriver lug, the trademark is still known as "the London card". Around the 1840 ad, nettleford improved wood screw, the pointed. A screwdriver and has been moving forward.
Air pump
Interested in Magdeburg, Germany's mayor Gerik to scientists and philosophers on the possibility of the formation of a vacuum debate. As an engineer with specialized education, he decided to solve this problem by experiment. In 1650, he created the first air pump -- as a manual pump, but the production of precision parts, airtight. The air pump is successful. He pointed out that, the exhausted air in a container, not to hear the bell, candles without burning, animal will suffocate.
His large-scale demonstration is very impressive. Have an experiment in the presence of emperor Ferdinand Sans's court in its front face open. In this experiment, the peripheral flange two hemispheres of 12 feet in diameter is coated with grease, the two hemispheres of the flange chimeric, and then the ball in the air exhausted. 8 horse will pull into two groups tied to the cables in each hemisphere also failed to separate, but into the air, they separated. In another experiment at the 1654 ad, a vertical opening is below the piston cylinder vacuum, with 50 people pull a rope tied to the piston, they have been driving the piston. It is in this way to make the piston to do work; piston must always have a vacuum.
However, no air pump to form a vacuum? After many years, people found that steam can solve this problem. In 1698, Thomas Savery first using the steam drainage, so that the steam into a sealed container, and the container spray cold water, so that condensation of steam in the, resulting in vacuum. He used this vacuum pumping from the mine, and using the boiler steam to the water container emptying. This cycle repeated.
Savery device called the "Friends of the miners". It has no pistons or moving parts, nor an engine, but only one pump.
In this past 1690, Denis parping France have created a model of equipment, a piston diameter of 2.5 inch just can be put into the cylinder. Filled with a small amount of water in the cylinder, he can by continuously heating and cooling water approach, that the cylinder cooling below the piston vacuum forming. Although this device does not have practical applications, but it is the first use of condensing steam pushes the piston and power equipment.

In 1712, the 3 achievements of Gurik, parping and Savery together, Thomas Newcomen Dartmouth made a practical steam engine.
Hooke invented the universal joint
In 1676, Robert Hooke, known as the "British as Finch" published on his
"Sunglasses" speech. This is a table with mirror system equipment safety observation of the sun. This instrument is a joint for his novel control. Universal joint is a universal instrument...... For curved track through any irregular produce circular motion. Although the method of making Hooke more detail about this new instrument, and vaguely pointed out, the instrument may be used in various aspects, but he just want to use it for astronomical observation, or used in the design of clock and a sundial, so at that time did not cause much attention.
Hooke is a man full of wit, he put forward the revolutionary theory of physics, chemistry and geology of the remaining in the system, in the London coffee shop with like-minded friends to endlessly debate over, to engage in more than twenty invention. His diary often allude to some new ideas in his highly active mind gradually forming. The Royal Society meeting records, records that his latest discoveries are well-known experiment.
However, diary and did not say he on the cardan joint spent a lot of time; he did not want to demonstrate the universal joint. On this machine, invention belongs entirely to his personal view is no doubt. However, in the power transmission, before the nineteenth Century revolution in transport, like many other inventions, does not need a free joint transmission in every direction.
Vala invented the governor
Centrifugal governor Watt in a steam engine invented in 1789 for use in, at the time caused a sensation is not too big; Watt attaches great importance to power system, only the governor as an attachment to the steam engine. However, it was the first computer by changing the fuel input and effectively control the speed of the device, is that a machine can automatically adjust the ancestor of all feedback device, the invention of history has been in doubt. Watt's governor is composed of a pair of centrifugal pendulum, rotating flywheel connected most distant and steam machine, directly connected to a sleeve, the sleeve and the valve inlet connection cylinder. When the flywheel to rotate faster, two ball will swing outwards, make the sleeve down; when the speed slows down, the sphere with ptosis, force the sleeve up. Steam valve can be a small open, to maintain a uniform velocity.
Watt governor history, can be traced to the medieval and Renaissance machine is sometimes used to ball and chain device or a ball and bar device instead of flywheel. However, these devices only play the function of the flywheel energy storage, the drilling machine, through the crank or produce a regular exercise to drive the tool over the "dead"; they can not control the speed or power input, most just to inspire governor modeling. Until the mechanical development, people know the performance, understand the centrifugal force, before anyone thought to control the ball and rod assembly.
One mill worker often encounter is unable to use the strong wind. Because when the shaft rotates too quickly, stone easy to move up, expand between two pieces of stone in the distance, and clip in the two stone grain not ground. People close to two stone tension, so that to keep a proper distance between them. Until 1787, Thomas Meade came up with a method, the two put apart is hanging over the gear to drive the grindstone, through the chain and a universal joint promotion and the adjusting rod. Another of the pendulum is connected with the windmill wing plate, so that the latter changes with the velocity and zhang. The mill workers as long as the change of wing plates subjected to wind, can regulate the rotating shaft speed. Two years later, Stephen Hooper with rack and sector gear instead of the chain, design a can with it match the machine, obtained the patent right.
At the same time, the first driven by steam mill John Rennie built in London -- "Albion mill". Governor arranged and Mead governor. Bolton in 1788 May to his partner Watt wrote, "there is pressure or the distance between the top and bottom of a regulator grindstone grindstone. Adjusting device for this, the steam engine runs faster, upper and lower millstone is closed...... When the steam engine stops running, the top stone rose...... This is because the two lead ballast centrifugal force caused by. Running at full steam, rising lead ballast; running slow, lead ballast will fall. They pass this way to leverage effect." This was Watt's idea, because while the governor was originally used on the grindstone, rather than to the steam engine, but in the end of 1788, Watt on the basis of a use of the modified. Because he knew that he could not claim to have discovered the basic principle, therefore did not want to apply for a patent. He is ahead of competitors take security measures on the governor.
Flow ball bearing
Plug lini it appears Italy Renaissance sculptor and goldsmith (1500 ~ 1571), the first to see a circle of free rotation of the ball may reduce the friction between the two rotating body. In 1543, he wrote in his autobiography: "I have done a beautiful statue of Jupiter, put it on a wooden base. I'm in. 4 small bowls, half buried in the ball in cricket. The whole design is very delicate, a young children can be an easy job to make it move forward and backward and turn around.

But loose in the roll of ball bearing rolling contact lane, until the last 25 years of the eighteenth Century began to use in the windmill. The use of the ball bearing is post windmill windmill (about 1780), the whole structure around the central column of the rotating machine. In 1794, Welsh in Carmarthen a man named Philip Vaughan, iron manufacturers to ball bearing as the axle bearing four wagons, and applied for a patent. From then until nineteenth Century, especially in nineteenth Century in the 50's and 60's, the ball bearing used in the merry-go-round, propeller shaft, children play on a warship gun turret, armchairs and bicycle equipment such as the axis, and achieved a number of patent right. However, until the powered vehicle appeared, metal parts due to run fast and there is a great deal of wear, this invention began to be fully utilized. Therefore, before the emergence of a large number of automobile production and precision of ball mill, ball bearings and did not really play a major role as it is today.
Drive chain
In 1864, Slater won a drive chain of the patent, the first step in this chain can be seen as the development of a can drive the bicycle and other mechanical precision. He made textile machinery chain in Salford a factory. The factory was bought Swiss reynolds. Renaud again in 1880 to obtain the patent Bush chain. The sleeve is installed in the chain, Bisilaite design can provide large surface bearing much.
The design of the earliest transmission chain known as Finch is painting, however, did not know he drive chain painting really made. We are from Ramelli's "different artificial mechanical" a book, you can see a pumping machine illustrations in 1588, this pump is the use of chain transmission. The chain has a square links, and tooth matched protruding wooden wheels, each square ring with 3 oval link and a square ring.
As for the transmission chain of metal and rare and expensive, and the lack of tools to make good, so the transmission chain is not widely used. However, to the early nineteenth Century, with the industrial revolution's sake, drive chain been applied widely.
The rear wheel with chain drive in the first French bicycle is designed by Girmay, by Meyer and Jiai in 1868 produced. Although the transmission chain has been in use for some time, but is mainly used in textile machinery, bicycle chain is still quite poor. Later, a Frenchman named Zhu Zan in 1885 successfully developed the so-called "modern bicycle", its two wheels are generally large, chain drive wheel. The British Stary in 1885 created called "secure Rover" bicycle. A new improved the bicycle rear wheel, but still with a transmission chain drive. So the Coventry became Bicycle Center, began the modern bicycle era. The people later and the chain transmission principle for motorcycle and automobile. Now, drive chain accurate has become one of the most important parts of industrial machinery.
Grab the king
For decades, the workers rely on artificial use of 28 mm thick steel wire rope tied to the cabin logs, and then use a crane to lift. Year after year, who also didn't think anything of it. But one day, a man was willing to change this backward situation. He is Bao Qifan, known as the "king of grab". Speaking of his invention of the grab, also speaking from the bloody incident.
In 1968, at the age of 17, Bao Qifan graduated from junior high school, a "Cultural Revolution" ruined his culture, high school dream. He had to go to the Shanghai port wood handling company registration, as a stevedore. Since then, Bao Qifan and wood, crane dealing. Summer, hot in his cabin, and the workers should also be in handling logs; winter, wood is a thin layer of ice, they must also complete loading and unloading tasks on time. Under such conditions, a little inattentive, will disaster comes. -- those heavy and thick logs as only a "wooden tiger", may at any time to break the shackles of wire rope, falling down from the crane high, once hit in the workers of the body, the consequences be unbearable to contemplate it is.
Bao Qifan had witnessed such horrors.
One day, Bao Qifan and a colleague's cabin, I saw a crane to lift the big wood whirling in the air. Suddenly, the dangerous situation, a log slid down from the crane, pressure in the colleagues. Just listen to the "ah" sound, the colleagues in the Bao Qifan side down, the bright red blood out from my mouth. After the doctor's examination, hit a log broke 10 ribs colleague.
The accident occurs frequently in Bao Qifan's side, since he entered the company, there are more than 500 people were seriously wounded or injured, killed more than 10 people.
The same accident took place at Bao Qifan. It is a day in the spring of 1974, Bao Qifan was pulling wire rope tied the log cabin, he put a rope hanging on the hook, hook up, his left thumb with gloves dragged broken, blood DC, the white bones sticking out of hand. Good after injury, Bao Qifan to enter the cabin handling logs, and then be wood injured leg.
Faced with this situation, Bao Qifan thought: "this method of backward and high labor intensity, low production efficiency, it is a formidable 'Tiger'! I must do something, a rule governing the 'wood tiger'!"
Due to injury in the body, Bao Qifan had to leave his blood spilled over jobs, came to the shop when the repairman. This is Bao Qifan, where they want to dosomethinpreviouslyunreleased. So, he went to the Xinhua Bookstore to buy a lot of books -- "mechanical drawing", "Turner foundation", however, on a cultural level is the only junior high school the second grade of the people, to read read through the thick book, easier said than done! Bao Qifan really wanted to have a new learning opportunities, fill this lesson of scientific culture.
The chance came at last. In 1978, the University resumed recruitment, Bao Qifan have got one's wish, to obtain the second Shanghai industrial university. Of course, he is reading the part-time Amateur University, 4 days of full-time study, 2 working days.
From the junior middle school the second grade level you want to jump to the University, one can imagine the difficulty is. However, Bao Qifan but advance despite difficulties. Trigonometric functions, analytic geometry is first encountered, but people do 10 exercises, he could do 20, 30; electrical, optical, mechanical though it is really hard to understand, but the review 1 times, he will review 2 times, 3 times...... Hard work pays off, backward learning difficulties to overcome in a little bit, step by step, and Bao Qifan is improving day by day.
In order to make the junior middle school, high school, he went to the bookstore to buy mathematical self-study series, every night after I finished my homework from the basic knowledge of the complement. Bao Qifan also worked out a set of his own method of learning, he took the thick book is split into several thin book, in his pockets, go learn where, the side of the road, the station, the car...... All the time he was sporadic use up. So, Bao Qifan finally catch up with the pace of learning.
When it is hard to read, Bao Qifan also did not forget to overcome "the wood tiger" mission.
Usually, Bao Qifan often walk on the edge of the pier, to see the other companies in the loading and unloading sand, pebble is grab, up and down, one of a, very comfortable. So, he thought: sand, stones can grab, why wood cannot grab? Yes. I have to make a safe can catch the wooden bucket.
He used to read free, and to study their work cabin for several years; he also went to the library, information, information room, looking for data search formula; back home, he made a grab every kind of model also used cardboard......
The test again and again, a failure again and again, are the key to opening and closing structure Grab: grasping the wood, it must open wide; grabbed the wood, it must be clamped tightly closed mouth, wood, don't let the wood spondylolisthesis.
One day, Bao Qifan sewing machine parts her down, and made into a small bucket, and then two rope instead of hoisting rope, up and down, back and forth to relax tightening, hey! This little gadget could grab.
After intense drawing design, manufacturing processing, Bao Qifan finally dream come true. The first timber grab method successfully! Time is in 1981 October, this is Bao Qifan will never forget the day, he watched his invention of grab easily handling of logs, hearts filled with a sense of pride.
The first grab Bao Qifan invention called "double solman grab", it is to use two hoisting rope to grab the opening and closing of. The grab, the workers came from the "tiger's mouth" out of.
The invention not only make Bao Qifan won the National Invention Award, yet he won the sixteenth session of Geneva International Invention Award!
After graduating from University, Bao Qifan transferred to the technology as a technology company, which made him feel just like a fish in water, almost every year new invention.
In 1983 October, Bao Qifan was elected as the representative of the trade union, went to Beijing to attend the National Federation of trade unions held
"The big ten". At the opening ceremony, he suddenly found that Congress issued to each representative as the record ball pen telescopic structure is very flexible, "Hey, this structure can be used to I grab it?" The so-called real
Hearts which have a common beat are linked. It is the ordinary ball-point pen, Bao Qifan thought can be "double rope grab" changed to "single rope grab", with a rope can be opened, closed grab two movements.
At night, the delegates went to see the film, and Bao Qifan stayed in the dorm to hold this ballpoint pen out of the God, the ballpoint pen is how the structure? For several nights, he did not draw any conclusion.
Once back in Shanghai, Bao Qifan is a ball-point pen factory to the West Bank of the Huangpu River, to the workers ask ball-point pen core telescopic mystery. However, the reception of his people thought he was counterparts, is to steal information, very strange to him. Bao Qifan still did not give up, go to the company opened the letter of introduction, it still doesn't work. Later, he several times to ask for advice, finally moved the ball pen factory receptionist. When they know Bao Qifan is to grab the invention, just hope the extension principle to understand the ball-point pen cores, no other meaning, the reception staff to "secret" told him.
Bao Qifan seem to have hit the jackpot, immediately put a strain on the invention. He and the workers at the test site working continuously for 3 days and 3 nights, even the Spring Festival is spent in the dock. In this way, "single rope grab" was born! I saw two pairs of parallel claws, inserted into the logs heap, log on homeopathy rolled to grab, hoisting gently starting single rope grab, is clamped tightly logs, immediately bundles from the cabin to catch up.
A new kind of grab bucket in the Bao Qifan finally assiduously born.

Conveyor belt
Large-scale production of modern industry mainly depends on the conveyor belt.
Henry Ford designed the first large "assembly line", for large scale production of the famous model T Ford (this car is the 1908 start of production). In most of the European car we still use manual manufacturing, specifically for the mass production of installation of the conveyor belt is Ford new car factory in the heart. It has 1 / 5 miles long, but the idea is based on the replacement parts. Replacement parts can be traced back to the beginning of the industrial revolution.
In 1789, the United States of America teacher Whitney (Gin inventor) with the government ordered a contract: within 15 months the government in the hands of 10000 shotguns. If using traditional method, making the gun workers from a to Z a gun is a gun to build, build so many gun can not be envisaged in the 15 months. So Whitney came up with a new idea, put the guns work break up the whole into parts, every worker with a continuous operation of the production of a component, all components must be made very accurate, can replace each other.
At that time, it is a completely new, need new tools. For this, Whitney designed the workers for fixture using a file, plate in place can get up to 12 holes, so that the production of the workpiece is not fixed on the machine is too long or too short on lathe the stopper, mould for casting the various components. Whitney brought several bags, each bag containing 10 of the same components, the Finance Bureau to go to Philadelphia, called the Finance Bureau officials in each bag of arbitrary took a part. He used these parts when these officials assembled into a complete gun. Whitney proves that this system is very effective. Than "good assembly" more amazing thing is, he proved not skilled gunsmith manufacturing parts with the facts, but by a skilled mechanic manufacturing components, can be assembled in a very short period of time.
Ford is another important factor to help the development of the belt conveyer, this kind of machine in the nineteenth Century in development, is mainly used to transport bulk goods at the port of. Liverpool have installed the first large grain conveyor in 1868. While Ford has used his assembly line is the assembly of the automobile continuously from a worker to another worker. Each has the tools and parts of the workers, must be finished within the time given a piece of work. Workers continue to work, the workpiece does not stop transmission. Electrical equipment
The invention of the galvanometer
One day in 1780, when the galvanic (Professor of medicine Italy Bologna) give students lectures at home, his wife was next door to the kitchen with his scalpel to peel the skin of frog. As she worked, while listening to her husband carefully, don't feel spellbound, operation knife from his hand slipped to put on the zinc plate on the frog leg. The frog suddenly rapid twitching, scared Dexi Geluona • galvanic a scream. Galvanic Professor rushed into the kitchen, see what happened. After some research, he immediately announced to the students: "I have a great discovery, found the origin of animal electricity -- life!"
However, he did not make any great discovery. All through his life he insisted this wrong view, made numerous experiments, with a dead frog of course, what also not confirmed. However, this makes his fame spread throughout Europe, made his name forever with "electroplating", "electricity" and "current" these terms together. Pavia voltaic -- a Bigafani more great scientists -- the correct interpretation of this mysterious phenomenon. Voltaic said: tic frog did not prove what "the origin of life", only the electric conductor; dissecting knife is made of steel, zinc plate is made of -- it is the more important factor. Voltaic pointed out, use a damp conductor separates the two different kinds of metal will have current flow. Tic frog thigh that current existence. Volta in this invention on the basis of the first battery -- voltaic pile. However the voltaic pile produced electricity was absurdly called "galvanic electricity".
It is a matter of the 1800, since then, scientists had an effective power supply used to do the experiment. Long-term since, they have long suspected that there is a relationship between electricity and magnetism. In 1819, Danish physicist Oster discovered by accident, a current through the wire to get near the mariner's compass, the compass pointer will be violent swing. The magnetic effect generated by the current, as an instrument for measuring low current (current) principle.
Eighteen twenties, various researchers developed into various forms of galvanometer was, and for Germany in the observatory, Gauss first used to send the actual use. In 1832, he invented the first telegraph (although it has put forward the idea of French scientists Ampere before). Gauss used the needle close to the current will deflection phenomenon, through a wire conveys the signal from the home to the observatory. This is called the moving magnet galvanometer. Is the moving-coil galvanometer or galvanometer however now the most widely used. Consist of a coil which is composed of a thin metal wire tightly wound into a coil, suspended in a magnetic field. When the current is switched on, is applied to the coil on the "torque" for the suspension wire "torque" balance, deflection angle measurement by a mirror mounted on the coil of the range, a small lamp and can read unit of electric current (Amperes) of the table to.

The 1866 in Europe and the Americas between laying the first exciting permanent telegraph cable (in 1858 had laid once, but failed), galvanometer plays a decisive role in. Outstanding British scientist Professor Thomson -- later known as Lord Kelvin -- in the cable laying ship "Great Eastern" using galvanometer to continuously detects the current flowing through the cable (if there is a current words) size. Across the submarine cable in the Atlantic is 2500 miles long, from the current telegraph signals into, from the the Atlantic shore to shore, of course, is already very weak, therefore, Thomson design is the most sensitive galvanometer. He used the recorder called "siphon recorder", including an extremely fine glass rainbow straw, Blackwater due to capillary action can flow in the tube, the arrival signal recorded on tape. A coil galvanometer pickup signal itself consists of a tiny metal wires around, between the two magnetic pole coil suspended in a horseshoe magnet. No siphon recorder Thomson, to maintain reliable telegraph service between the two continents, and kept it for many years, is simply not possible.
Frog leg enlightenment
Italy Università degli Studi di Bologna professor of anatomy galvanic has a well-equipped laboratory. In many specimens, anatomical tools; and like motor, Leiden bottle and other electrical equipment. Galvanic early to study theology, later to study medicine, is an authoritative scholar on human body, disease and treatment.
One day in 1786, Galvani guide for students of anatomy. There was a naughty student not seriously to do the experiment, but on the next play motor occurred interest, he does not pay attention while Professor shook up the motor, suddenly snapped up motor and frog legs copper hit a big spark, the students jump. Galvanic and classmates turned around, but at a more strange phenomenon has aroused the attention of everyone, the metal disk in the frog legs with electric shocks twitched, the professor's eyes widened, he did not criticize the naughty students, and let him play electric machine from shaking, all the students looked at the frog legs, PA of a copper coil and hit a big spark, frog legs with electric shocks and twitched, the students I see you, I see you there were many discussions.
Galvanic came, with the tip of turning the scalpel a frog legs to explore what the frog legs, like to live suddenly beat, it can make direct be startled at, he with a shaking hand and touching the frog legs, it caused frog leg muscle twitch. The experimental class could not normally go, all the students went back to his desk with a scalpel to touch the legs to be able to see the same phenomenon, but some students can make the frog leg twitch. Others can not, like a pot in the classroom, students in the lab to run, galvanic could not afford to students, but troubled with a scalpel to touch the legs, until the bell rang.
Although the galvanic do not know the truth, but he like all scientists did not miss any accidental phenomenon. He spent 11 years of time to study this matter.
One day, galvanic copper wire hook the frog leg put some frog legs hanging to the iron balcony railing to dry, a breeze blowing, frog legs dangling over the railing, Galvani found frog legs every time it hit the iron railings to jerk, this incident has caused his thinking. He stared at the strange phenomenon of one's pupils do not turn. Suddenly had an idea: frog leg power from the atmosphere and organism, but this is a wrong conclusion.
One of the most is not willing to accept the "electrical" people is the galvanic fellow Italy University of Pavia physics authority Volta, Volta's personality is introverted, childhood is a very quiet child, he 4 years old before he could speak, the family thought he is mentally retarded, but at the age of 7, he catch up with and surpass the other students, 14 years old when he decided to become a physicist. Therefore, the photovoltaic develop the habit of thinking and not blindly. Voltaic noticed in stamp frog legs, one metal or without metal legs is not tic, when only two metals exist at the same time, frog leg will twitch. This phenomenon Galvani have observed, but do not understand, this phenomenon has caused the Volta's thinking, he seemed to feel the truth in it.
Voltaic with two kinds of metal produced a crooked stick, a head of is steel, one is iron, middle together. He put a head on the mouth, another head on the eyes, a moment when the metal rod and eye contact, there is a flash in the eyes of the light. If it is the same kind of metal into the bar would not have this phenomenon. Another time he licked a gold and a silver coin, when with a wire connected to the gold and silver coins, the tongue will taste bitter. These phenomena Volta that are electrically caused. Rather than a biological characteristic, however, where the electricity is coming from?
He thought might be from two kinds of metal and saliva. Saliva is a complex chemical, it can make the rusting of metal, in which chemical reactions will produce electricity?
He caught a piece of cloth on a layer of saturated brine between two kinds of sheet metal, electrical immediately strengthen many times! Current and can output stable.
Success.
Voltaic extremely happy.
"Is the chemical reaction! Chemical reaction to generate electricity, frog legs twitching just to test the electricity, the electroscope."
He understood the true cause of leg frog twitch: leg frog contains water and salts, scalpels and copper coil steel is two kinds of metal, when the middle of two kinds of metal salts with time will produce electricity, has nothing to do with the frog leg itself. No frog legs for a different method can also produce chemical reaction current test.
Voltaic further experiments, he used the copper and galvanized iron placed alternately, separated by a middle layers of bubble in a saline solution of cloth, known as a "voltaic pile" things made, this is the modern battery.
The battery then improved, many scientists in 1887, the British Helsen invented the first piece of dry battery, the battery is easy to carry, dry battery electrolyte is a sticky substance, so the liquid can not overflow.

From the electric magnetic variation to the electromagnet
In early nineteenth Century, Danish physicist Oster playing battery improvements to the volt, had done all kinds of current research, especially on the relationship between electricity and magnetism.
One time, he found that when the current flows through the wire in the experiment, the needle is placed in the copper wire side produced a trembling jitter. Oster was surprised, I do not know why the needle swing. So, he repeated the test, to find the cause of the jitter.
He will needle placed in parallel wire below, when there is a current through the wire, the needle is a factory to swing; and when the needle parallel on the copper wire, and copper wire is energized, the needle is in the opposite direction swing; when needle and wire is very close, the needle swing angle in the biggest, up to 45 °; while in the needle gradually left the copper wire, the needle swing angle also decreases.
Then, Astor also with wire, brass wire instead of copper wire for the same test, but the result is the same. Then, he again between the needle and wire placed in glass plate, water and wood, carefully observe. Even so, the deflection swing needle remains the same.
OE of these tests, results show that: when the current flows through a wire, produced like magnets magnetic conductor near, namely current also has magnetic force and magnet. In 1820, he published the results of this research, scholars have caused attention and attention, also opened a prelude to an invention.
Later, the French physicist Ampere according to his findings made a more in-depth study. He found that in the experiment, two parallel wires, if the current flow in the opposite direction, you will see two copper attracted each other and near; and current flowing through the same direction, two wires are mutually exclusive and away from the. Ampere also through this experiment established a formula is the most commonly used computational electromagnetics, people often say that the Ampere's law. But more importantly, A got such insights: can through the current coil instead of the function of the magnet.
In addition to the ampere, the French scientist Guy Lui Sack of oersted's experiment was conducted to study the. He also made a coil like Ampere in the coil, and hung a needle. When a current passes through the coil, he found that the needle was magnetized, became a permanent magnet.
By 1825, the British sturgeon by soft iron rod instead of on the steel coil test, results of soft iron rod has become a magnet and a needle. But when cut off the current, and the needle is different, the soft iron rod has not become a permanent magnet. Sturgeon is amused. He thought, if the current will flow through coil alternately switched on, off, a current soft iron is magnetic, and cut off the current magnetic soft iron will disappear, this is not exactly what people need the kind of "electricity variable magnet"! So, he delve into, finally invented the electromagnet.
The invented by Sitkin, is the soft iron bar made of U shape, which we usually call horseshoe, and then coated with varnish, again above around 18 laps around the copper wire.
When Sitkin made an electromagnet, the United States of America young scholar Henry gave a high evaluation, and the electromagnet of Sitkin have been improved. Henry is not a varnished in soft rod, but the soft iron bars around the insulated conductor, magnetic electromagnet made more.
Shortly after the invention of the electromagnet, the generator and the motor will have come out in succession, they have adopted the U as the main part of the electromagnet. The significance of the invention of the electromagnet. In addition, now many electromagnetic meter, as well as several hundred kilometers per hour high-speed maglev, are also "play". Therefore, the electromagnet and the prospect of brilliant.
Faraday invented the transformer
Edison invented the electric light, but there is a problem to make him very difficult. Because, at the time of transmission distance of not more than 3 km, later, current along the wire to go too far the voltage drops, can't light point very clearly, only a yellow halo of light even better gas lamp.
If the transmission voltage, near the generator lights will be burned, in order to solve this problem, Edison in about 3 km radius of the area, built a braved the smoke, the rumble of the power plant. People often complain about the noise, vibration generator and soot, but, in order to solve the increasing demand, Edison or investment.
As Edison plans to build a power station in time, because the method of the invention of air brakes windfall Westinghauscagyaw Edison has great limitation, he kept thinking what better way transmission, just at that moment he heard, a French chemist and physicist Goral in 1882 invented transformer, this provides a key to he solved the problem, he immediately to buy his patent.
Transformer's prototype should be invented by Faraday, he once had done a test, is the two sets of coils wound on the same iron ring, when energized coil in a moment, in another coil can sense the current. Power also induces a current. But when the steady direct current outdated, another coil current also does not have what. Only through the alternating current, another coil can continuously induced current.

This current magnitude and direction changing, called alternating current. Although the current size changes, but is not the point lights, because the current instantaneous fault, filament have not had time to cool down, and turned on the light, do not flicker.
However, when Westinghouse bought the patent after the discovery, the transformer faults, but also organize special team.
In 1885, the formal establishment of the Westinghouse Electric Company, second years spring is realized by transmission network 3000 volt high-voltage transmission of 6.4 km.
The new results immediately attracted everyone's attention, the company's business is booming, Westinghouse is not satisfied, he learned that there is a call Tesla young people in the Research Institute of Edison, is a study of AC motor, made a special trip to New York to visit. Tesla was born in Croatia, studying engineering at University of Hungary and Graz, later moved to the United States of america.
Tesla is a temper some odd people, some contradictions between him and Edison, later Tesla ended with Edison's cooperation, Westinghouse with a $1000000 price to buy more than 40 pieces of patent Tesla, to use his new technology development of AC motor.
Edison on this quietly opponent was furious, and launched a campaign of slander the AC propaganda war, he spent thousands of dollars organizing news, magazines and posters, to the outside of the AC terrible, WestingHouse also not resigned to playing second fiddle, battle of wits to fight back, however, he didn't expect, New York court decided to use alternating current to execute prisoners to death, also said that only AC is to quickly die effect, this is Edison doing here, is a fatal blow to WestingHouse.
In order to offset the impact of the Westinghouse Electric chair, looking forward to an international conference held in Chicago, just to commemorate the 400 anniversary of the discovery of America Kolumb international exposition, as one of the quality meeting, is to light 250000 lamps, Westinghouse spare no effort to undertake the project at a very low price competition. In May 1, 1893, tens of thousands of lights shining in the night a dazzling spectacle.
At the meeting, the Niagara Falls construction company manager proposed a hydropower station. But this hydropower station far away from the city, after he saw Wei's at the exhibition on the achievements, decided by him to undertake this task. It is only with the alternating current and transformer to complete.
In 1892, Edison of the Ge Corp and miserably due to DC claims, the company ordered Edison to withdraw from the company, and to remove Edison 3 words, changed its name to Ge Corp, and reaches out to Westinghouse, two, repair, common use technological achievements, while Edison and can not operate power generation business.
Now any a street can be seen on the transformer, power plant generated electricity increased voltage to the hundreds of thousands of volts, lost to the city after the voltage drop down, greatly improves the transmission efficiency, reducing the loss. Raise and lower the voltage cannot do without transformer.
Laser
Laser is one of the most important scientific and technological achievements in the 60's of this century. With its high brightness, high directivity, high monochromaticity, high coherence and other prominent features, has been widely used, and has opened a new growth point in many important fields of science and technology, caused the revolutionary change.
In 1916, Einstein published "the quantum theory of radiation" one article, first proposed the concept of stimulated emission of radiation. According to this theory, in the material particle energy state by an energy equal to the energy difference between the photon two level role, will shift to the lower energy state, and produced second photons, with the first photon emitted at the same time, this is the stimulated emission of radiation. The radiation output of the light received amplification, and is coherent, i.e. two photon direction, frequency, phase, polarization are identical.
With the establishment and development of quantum mechanics, there is a better understanding of the microscopic structure of matter and its motion law, micro particle energy distribution, transition and photon radiation has also been proved more powerful, this objectively better radiation theory of Einstein, laid the theoretical foundation for the laser. Produce. At the end of the 40's, the interaction of quantum electronics, it mainly studies the electromagnetic radiation and all kinds of micro particle system, and thus developed a corresponding device. These advances in theory and technology, will prepare the conditions for the invention of laser.
In 1951, the United States of America physicist Purcell and Pound in the nuclear induction experiment, add in the work material on the field suddenly reverse, the inversion result in nuclear spin system, and obtained the stimulated emission at 50 kHz, which is of great significance in the history of the laser.
In 1954, American scientist Towns and his assistant, Gordon, Cai lattice together, the first ammonia molecular beam maser made. The maser generated microwave 1.25 cm wavelength, power is very small, but it had successfully created as microwave radiation coherent amplifier and oscillator using molecular or atomic system precedent, so it has great significance. Almost at the same time, the Soviet Union and the United States of America Basov and F Rojo Love Weber of the University of Maryland, also independently proposed maser thought.

Because the maser success, make people think further, if the maser principle is extended to the optical frequency band, makes it possible to create a coherent optical radiation oscillator or amplifier. Production and the development of science and technology, but also promote the scientists to explore the luminescence mechanism of new light source, to produce a new performance.
In 1958, Schawlow and Townes will maser and optics, spectroscopy of knowledge are combined, the key recommendations of an open resonator, and predicted that the coherence of the laser linewidth, direction, and noise properties. During the same period, Basov, F Rojo Love also proposed the implementation of principle scheme of light amplification by stimulated emission of radiation.
In 1960 July, the United States of America young scientist Maiman succeeded in manufacturing and the world's first laser operation. Artificial ruby with the working substance, the excitation source is pulse strong, it gained 0.6943 microns wavelength red laser pulse.
After the first laser was invented, the laser is developing very quickly, a short period of time has many different types of lasers. In 1961, 1964, has made of neodymium glass laser and titanium doped yttrium aluminum garnet laser, they and ruby lasers are still widely used by solid state laser.
By the end of 1960, the Baer telephone laboratory Jia Wan et al made -- helium neon laser first gas laser. In 1962, 3 groups of scientists almost simultaneously the invention of semiconductor lasers. In 1966, and developed into an organic dye laser wavelength can be adjusted continuously in a range of. In addition, there are large output energy, high power, and do not rely on network chemical lasers.
Due to various characteristics of lasers, which are applied to industry, agriculture, precision measurement and detection, communication and information processing, medical, military and other aspects, and has caused the revolutionary breakthrough in many fields. For example, concentration and high energy laser, can be processed on a variety of materials; laser as a kind of stimulation, variation, burning, vaporization effect in biological body means, it has achieved good results in medical, agriculture; laser in military communication, except for night vision, early warning, ranging outside, all kinds of laser weapon, laser guidance weapon has been put into practical. In the future, with the further development of laser technology, laser performance and cost is further reduced, its scope of application will also continue to expand, and will play a more and more important role.
Fiber mirror
Can bend angles were observed by microscope, is a wonderful instrument developed thinner than a human hair several times after the glass fiber.
Development of the first problem fiberscope meet, is shaped like a shoelace like mirror, but have their own light source. Have certain refractive index of glass covered rate of different glass rod in a refraction, may meet the law of reflection, in other words, the light will travel along them without loss. So, no matter how far distance, to turn many bends, people can see the "inside the case from the outside".
The biggest difficulty is made of very fine glass fiber, fine to put a bunch of glass fibers inserted into the body of the pore, for hypodermic needle inserted into, or through a leakproof seal within the internal condition of observation of mechanical a working example of a nuclear reactor. Glass fiber has two kinds: one kind of transmission "coherent" light, produce an image in the eyepiece; another transmission "incoherent" light, to illuminate the target internal to. By shining a thing through the formation of two kinds of beam form, form an image at the eyepiece or camera.
Britain's Atomic Energy Agency, and the recent Ranke organization, has pioneered the development work in this area, to 1965 has begun production of 25 microns (1 micron equals 0.001 mm) glass fiber. A number of Usa Inc, the most famous is the Bao Xuelong company, has been committed to the development of more fine glass fiber, the results developed 15 micron glass fiber. Fiber mirror Bao Xuelong's first in the industry to do the inspection work (because it is issued by the cold, so is suitable for testing the fuel tank). The United States of America systolic mirror company to glass fiber disinfection to succeed, it opened up broad prospects for the application in medicine. Bronchoscopy (let the patients swallow) and gastroscope (used to check the stomach) are usually 7 microns thick bundles of glass fibers. However, before the camera with the camera in the failed, for millions of dollars in research and development is not back.

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