Into Unscientific Chapter 296

  Chapter 296 Cathode, cathode!

  As a posterity.

  When he saw the group of discharge tubes in front of him, Xu Yun couldn't help feeling a sense of witnessing history.

  Low pressure gas discharge tube.

   This can be said to be an enlightenment device for human beings to really touch the microcosm. In addition, it has a more standardized name in concept.

That is.

  Low pressure gas electron tube.

Of course.

  The concept of the electron tube has not yet been born, and it will not appear until 1904.

  At that time, John Ambrose Fleming, a student of Wheat, made his debut and invented the famous electronic diode.

   Then in 1906, De Forest invented the triode.

   Further on, there are point-contact transistors, semiconductor triodes, p-n diodes, and glow tubes.

   Waited until 2022, when Xu Yun traveled through time.

  The experimental device of gas discharge has been optimized to a limit at the laboratory level.

  For example, SMD1206 representing the package ceiling, YINT representing the extreme value of performance, and GDT representing the peak value of surge absorption capacity, etc.

   At that time, let alone ordinary gas discharge tubes.

  Even Nixie tubes have been eliminated for a long time, and have become a small category with a slight collection value.

You can buy a good glow clock for a few hundred dollars on a certain treasure—but you have to check whether it is glow or pseudo-glow before placing an order. It's actually quite interesting to buy one if you have the conditions of.

all in all.

  Compared with 2022.

   Faraday and the others prepared the experimental equipment this time, which is undoubtedly extremely simple.

But on the other hand.

  Simple, but not shabby.

most of the time.

  History ushered in a certain key node in this so-called "dogs can't look down on" conditions in later generations, thus opening a new chapter.

  The line of sight returns to reality.

  After everything is ready.

  Faraday put on his gloves, brought Xu Yun and others to the side of the equipment, ready to start.

   Pumping mercury.

  The suction outlet of the modified Gessler tube or anti-inflammatory tube is set in the middle of the test tube. It roughly looks like a small opening is opened, and then connected to the outside with a hose.

  The operation process is to use the external pressure valve to extract the mercury in the tube.

  Once all the mercury is extracted and the magnetic circuit of the armature in the external relay is closed, a vacuum of one hundred thousandth can be achieved. (A reader left a message asking if there are any related books. Here are two recommended books, "Gas Discharge" by Mr. Yang Jinji, and "High Voltage Insulation Technology" by Mr. Yan Zhang)

   Then Faraday gestured towards Kirchhoff, and Kirchhoff hurried to the other side of the table when he saw this.

Then

  Holding a handle more than half a meter long, he began to fiddle with it like a shaker.

   That's right.

  This kind of coolie-style operation was the most effective method for vacuuming in 1850.

no way.

  Time is limited.

  There are many ways to pump vacuum in later generations, such as mechanical pumps, molecular pumps, ion pumps and so on.

  Like a better ion pump, it can reach a vacuum of about 10^-12mbar.

  But the equipment in 1850 was not as fully mechanized as later generations. Before 1870, there were only two ways to extract vacuum:

   Reciprocating vacuum pump or oil-sealed rotary vacuum pump.

  The principle of the former is to use the piston in the pump chamber to do reciprocating motion, and the pump chamber is driven by manpower to inhale, compress and discharge the gas.

   Therefore, it is also called a piston vacuum pump.

  Oil-sealed rotary vacuum pump is a rotary variable displacement vacuum pump that uses oil to seal the gaps between moving parts and reduce harmful spaces.

   Relatively speaking, the latter is more efficient.

  However, the oil-sealed rotary vacuum pump needs to use a gas ballast device, and the preparation and operation links are relatively complicated, so Faraday still chose a reciprocating vacuum pump this time.

   "Hey hey, hey hey!"

  Looking at Kirchhoff who turned the handle like a fitter twisting a screw, Xu Yun suddenly thought of Brother Donkey in Lao Su's dungeon

anyway.

   When I return to reality, the female donkey bought from Wuzhou Mountain will almost be sent to school.

   At that time, it will be able to squeeze the cough, and the labor will be extra.

so good.

that's it.

   About five minutes passed.

  Kirchhoff stopped what he was doing, panted and wiped the sweat from his forehead, and said to Faraday:

   "Professor, the mercury has been pumped out, and the barometer is always showing normal."

   Faraday nodded and said:

   "Thank you, Gustav."

   Then he signaled Riemann to put down the curtains to block out all the light.

  He himself walked to the left side of the table, fumbled for a moment, and pressed a certain power switch.

soon.

  As the power is turned on, the external coil begins to discharge, the voltage at the two poles of the discharge tube begins to increase, and an electromotive force appears in the tube.

   And in the microscopic world that cannot be seen by the naked eye.

  Countless electrons emitted from the cathode move towards the anode under the action of the electric field.

  They encounter residual air molecules in the middle of the gap, and a series of collisions generate a large number of new electrons and positive and negative ions.

  Due to the high speed of electron movement, a large number of electrons are concentrated in the front part of the forward direction.

  The positive ions stay in the back, and a collection of electrons and positive ions is formed in the tube—this collection has a name in later generations, called electron avalanche.

at the same time.

   There are also other changes in a large number of ions:

  They recombine in the tube to form normal gas atoms.

  Students who were ions in their previous life should know.

  The so-called ion recombination actually refers to the process of electrons returning to positive ions.

   When the electron returns to the atom.

   will emit the energy it carries in the form of light.

  As the electron avalanche moves toward the anode, it becomes increasingly populated with electrons and positive ions.

   On the one hand, this changes the electric field distribution in the discharge gap, and at the same time makes the charges in the avalanche head and avalanche tail weaken the electric field inside the electron avalanche, so that its recombination effect is enhanced.

  The recombination of electrons and positive ions will generate a large number of photons, and the photons will act on the gas at the back, causing these gases to appear electric field ionization.

   Then a second electron avalanche and a third electron avalanche are produced.

  The head and tail of each electron avalanche develop towards the anode and cathode respectively, and finally connect into one piece.

until

  piu—

   With a small sound.

  A complete ionized gas channel is formed, and the gas gap in the tube is broken down.

   Also don't forget.

  Faraday previously filled the tube with mercury, a very volatile substance.

  Although they have all been extracted from the naked eye, Kirchhoff is not the elder of the Soul Palace after all, so some mercury still remains on the tube wall.

   Under the stimulation of voltage, they quickly form mercury vapor.

  So

  A blue-white light appeared in the tube, making people think of mio's blue-white bowl unconsciously.

  This is a special light effect unique to mercury. If it is replaced with sodium, it will appear yellowish white.

  See this scenario.

   Faraday couldn't help but leaned down, staring at the blue and white light in the coffin.

   I don't know whether I am lamenting the time, or admiring the magic of Xiao Yan Pavilion, I just heard this old man who is close to sixty years old mutter in his mouth:

   "It's been 12 years."

be honest.

  Compared with the 6% vacuum tube 12 years ago, the imaging of today's Xiaoyan tube is indeed much clearer.

   Faraday didn't even need a magnifying glass to see that there are several intervals of different brightness, which are distributed sequentially from the cathode to the anode.

"one two Three."

  Faraday counted carefully, turned to look at Xu Yun, and asked:

   "Student Luo Feng, there are six light and dark areas in total?"

  Xu Yun once said that 'Fat Fish' hadn't done this experiment, so he threw his hands at him neatly:

   "I can't make it."

  Faraday gave him a meaningful look, but did not speak.

   Then he called Weber and others to his side and recorded the phenomenon.

  From an observation point of view.

  Glow discharge is undoubtedly one of the more characteristic gas discharge phenomena.

  When the arc gap occurs, the entire space in the arc gap is discharging, and the temperature is not too high, and what restricts the observation is actually a degree of vacuum.

  The higher the degree of vacuum, the easier it is for glow discharge to occur, and the phenomenon is clearer.

  The condition of one hundred thousandth of a vacuum degree, even if it is delayed by a hundred years, can be considered passable in 1950.

  So Faraday and others can observe while making written records very freely.

   "Gustav, please remember."

  “.Starting from the cathode, a very short dark area first appears, which is slightly visible to the naked eye. Detailed observation requires the assistance of a magnifying glass.”

   "The second area is close to the first layer, with moderate brightness and can be observed by the naked eye"

   "The third block glows weakly"

   "The fourth area has a clear boundary, and the light is strongest on the boundary line, and then gradually weakens"

   "The fifth block is the transition area, which is the original Faraday dark area."

   Farah was the first to observe while narrating, his tone slightly trembling.

  Although I have already made some psychological preparations, I can roughly guess that the experimental phenomenon will be more impactful.

   But seeing the six clearly arranged areas now, he still couldn't help but feel a surge of complicated emotions in his heart.

  12 years ago, he really thought that there was only one Faraday dark area in the Nixie tube

  He is like a fisherman who has a good harvest during the fish season and caught an eel in a certain beach.

  He could roughly guess that there might be more eels in the sea in that direction, but he saw the cuttlefish school in another direction, so he gave up here.

   I didn't expect that with the improvement of precision, let alone the 'deep sea' behind the light.

  Even near the Faraday Dark Zone, which he thought was "that's all", there are actually a lot of wild big yellow croakers buried.

   And the other side.

  Looking at Faraday and others frantically recording the phenomenon, Xu Yun's expression remained relatively calm.

  He has done glow experiments more than once in later generations, and he is still familiar with the phenomenon itself.

   And actually.

  The area that appears during glow discharge is not six, but seven or eight. .

  The first one is called Aston dark area, which is a very thin layer of dark area in front of the cathode.

  In the original history.

   It was not discovered until 1968 by F.W. Aston in experiments.

  In this area, electrons have just left the cathode, and the flight distance is still short.

   They don't get enough energy from the electric field to excite the gas atoms, so they don't emit light.

  Adjoining Aston's dark area is the cathode glow area.

  Because the electrons have enough energy to excite atoms after passing through the Aston dark area, when the cathode glow area returns to the ground state, this area will emit light.

  Following them are Crooks dark area, negative glow area, Faraday area and positive glow column area.

   As for the last area not discovered by Faraday?

  It is actually a general term for the two small areas, called the anode bright area and the anode dark area.

  The conditions for the formation of these two small areas are relatively high, and they only appear when the current drawn by the anode is greater than the current that the plasma area can normally provide.

   Therefore, they are generally not regarded as common areas in discharge phenomena.

   Among all the above areas, the most important one is the positive pillar area.

  The concentration of electrons and ions in this area is about 10^15~10^16/m, and the concentration of the two is equal, so it is called plasma.

   Actually.

  This part of the region is dispensable for the glow phenomenon itself, and in short discharge tubes, the positive column region will even disappear.

   But in the field of derivatives, this thing is not good:

  Plasma coating, plasma etching, plasma physics, nuclear fusion, plasma propulsion, electromagnetic fluid power generation and other cutting-edge science and technology in modern microelectronics technology are all related to it

  At the same time, the connection between these technologies and the Zhenghuizhu District is not a slight fringe, but one of the solid basic research supports.

Of course.

  At present, Faraday and others don't know how much impact these areas will have in the future—they haven't even discovered the seventh area yet.

   Influenced by the vision of the times.

  They are completely unaware of what they have done, and how difficult it is to make the college entrance examination more than a hundred years later in this era

   After recording relevant data.

  Faraday, Gauss and Weber discussed and analyzed the phenomenon on the spot.

  I saw Weber's eyes fixed on the vacuum tube, one of the famous unlucky ones in the history of physics showed his keen judgment at this time:

   "The first dark area is much darker than the third dark area, and it is still much darker than the Faraday dark area."

   "But this area is obviously applied with an electromotive force, which means that the strength of the hardware equipment and the 'field' are the same."

   "Then there is probably only one reason for the dark area."

   Speaking of which.

  Weber couldn't help raising his head, looked at Faraday and Gauss, and said in unison:

"energy!"

  Xu Yun who was on the side heard the words, his gaze narrowed undetectably.

  The core reason for the dark area in glow discharge is that the excitation is small—if the cathode dark area is excluded, the other three dark areas can be said to be less ionized.

  The reason why these charged particles are not excited is because the energy of electrons is very low.

  Just like the eight and a half sticks, the area where it hits is the bright area, and the area where it comes out to store power is the dark area.

   Although there is still a thousand miles between energy and particle excitation.

  But with today's scientific cognition, it's really remarkable that Weber and others can think of the level of energy.

Of course.

  In addition to the abilities of Weber and others, a large part of this is due to Mavericks:

   It is precisely because he proposed the rudimentary theory of wave-particle duality that later generations like Weber can conjecture more freely.

   Then Faraday and others measured and recorded the test tube, and then began a more important link.

   Check the nature of this ray.

   First, Faraday walked to the side of the test tube and pressed a certain switch.

   With the activation of the switch.

  A small circular piece of wood that was originally attached to the inner side of the tube wall was put down, blocking the light path of the light.

  As the light path was blocked, within a few seconds, a clear shadow appeared on the right side of the test tube.

   Seeing this, Faraday nodded slightly.

  The left side of the test tube is the cathode, and the right side is the anode.

   Add a small object between the two, and the shadow appears on the right, which shows one thing:

   Rays originate from the cathode.

  Think here.

  Faraday could not help but look at Xu Yun, and asked:

   "Student Luo Feng, did Mr. Fat Yu name this beam of light?"

  Xu Yun shook his head:

"No."

  Faraday pondered for a moment, looked at Gauss and Weber again, and said after deliberation:

   "In this case, let's call it cathode rays first."

  Xu Yun was worried that Faraday would say some coquettish names, such as Aurora Jiba, but he was relieved after hearing cathode rays.

   As for the inertia of history, or the term that Faraday just thought of

   This is not something Xu Yun is capable of understanding.

all in all.

   After confirming that the source of the light is the cathode.

  Faraday's expression suddenly straightened, and his expression instantly became serious.

  His left hand behind him even trembled a few times in an extremely subtle way, but no one noticed this scene.

   Then he turned around with a serious face and said to Kirchhoff:

   "Gustav, let's add an external field."

  (end of this chapter)

Chapter end