Polarization refers to the phenomenon that things are polarized under certain conditions, making their properties deviate from the original state.asMolecular polarization(dipole momentIncrease), photon polarization（polarization)、Electrode polarizationEtc.Characterizing the property of the electric field vector (or magnetic field vector) of the uniform plane wave changing in the direction of space, it is specified by the track at the end of the electric field vector E of the sine wave at a given point.Optically, it is called polarization.According to the characteristics of electric field vector track, it can be divided into linear polarization, circular polarization and elliptical polarization.Since there is a clear relationship between the directions of H and E, it is unnecessary to describe the characteristics of H.
When analyzing the propagation characteristics of electromagnetic waves in an infinite uniform medium, the problem of the orientation of the field vector is not prominent, and the concept of wave polarization is not important. However, when there are boundary conditions (such as the interface between air and earth, the interface between medium and conductor, etc.), the orientation of E (or H) is very important.On the same side of the interface, waves with different polarizations or waves with different polarization directions will produce completely different results.In addition, when analyzing the reflection and refraction of waves on the interface of different media, the wave with arbitrary polarization is usually decomposed into the superposition of waves with specific direction polarization for processing.
Polarization is becauseelectric currentAnd finally lead to the phenomenon that the potential deviates from the open circuit potential of the electrode.When the current keeps moving, the cathode and anode will appear polarization.Polarization reduces the potential difference between anode and cathode, thus reducingcorrosionCurrent and corrosion rate.At the beginningcathodeThere are a lot of reactants around, which can reduce the amount ofElectronicsHowever, with the increase of cathodic reaction, the reactants around the cathode become less and less, and the products deposited after the reaction become more and more;Because the reaction products cannot be removed quickly, it prevents new reactants from approaching the cathode.The final result is that the excess electrons in the cathode area are not digested and become more and more.WithElectronicsThe cathode potential will slowly decrease with the increase.cathodic protection The principle of this phenomenon is used to reduce the potential of each point on the metal surface to the same potential value, so that the potential difference between the points on the metal surface can be reduced to slow down corrosion.On the contrary, ifCathode regionThere are many reactants or reaction products in the domain that are easy to be removed, such as in flowing water. At this time, if you want to reduce the potential to a certain position, you will need relatively more electrons, that is, it is difficult to polarize.For example, there are a lot ofOxygen moleculeThe cathode is difficult to polarize to the required potential.Able to consume cathodeElectronicsThe substance of is called depolarizer.The depolarizer comprises: 1. dissolved oxygen;2. Microbial activity;3. Water flow.When the polarization and depolarization are balanced, the potential difference and the corrosion current between the cathode and anode are stable.The corrosion rate depends on this final current.
In general, you can use someCorrosion inhibitorAdd to the aqueous solution to promote polarization.Such added substances can promoteanodePolarizedAnodic corrosion inhibitor。Can promotecathodePolarizedCathodic corrosion inhibitor。
electric currentadoptelectrodeWhen, electrodepotentialThe phenomenon of deviation from the equilibrium electrode potential is called electrode polarization.
PolarizationBatteryBetween positive and negative poles after being connected to the circuitVoltageThe decrease ofelectroplateandElectrolytic cellAn increase in the required voltage after starting work.Both of them are unfavorable, so we should try to reduce polarization.
anodeSuperprecipitationpotential(Positive value) is more than theoretical precipitationpotentialcorrections;cathodeThe precipitation potential on is more negative than the theoretical precipitation potential. The phenomenon that the actual potential deviates from the theoretical value is called polarization, and the difference between the actual precipitation potential and the theoretical precipitation potential is calledOverpotentialorOverpotential。
Depolarization of electrode
Announce
edit
Usually can be weakened or eliminatedPolarization processThe effect of is called depolarization.Increase the concentration of depolarizer in the solution, raise the temperature, stir and reduce the activationOvervoltageWill promotecathodeEnhanced depolarization;anodeDepolarization refers to reducing or eliminatinganodePolarization, such as stirring and heating, will accelerate metalcationThe speed of entering the solution, thus weakening the anode polarization.Add complexing agent orPrecipitant, they will interact withmetal ionThe formation of insoluble complexes or precipitates can not only reduce the concentration of metal ions in the solution near the metal surface, but also weaken the anode to a certain extentElectrochemical polarization。If some active anions are added to the solution, it is possible to makepassivationThe activated metal is in the activated state again.
Obviously, from the controlcorrosionFrom the perspective ofPolarizationTo reducecorrosionSpeed.But forelectrolysisProcess, corrosion processing, in order to reduce energy consumption, they often try to strengthen depolarization.be used asanodic sacrifice protectionThe smaller the polarization property, the better.
polarization of dielectric
Announce
edit
Under the action of external electric field,dielectricInner edgeElectric field directionGenerate inductiondipole momentThe phenomenon of polarized charge appearing on the surface of dielectric is called dielectric polarization.
dielectricUnder the action of external electric field, the following three types of polarization can be generated:
② The molecules whose positive and negative electric centers coincide are separated from each other under the action of external electric field, which is calledDisplacement polarization；
③ Have inherentElectric dipole momentThe original orientation of the molecules of,macroscopicThe total power on dipole moment is equal to zero. Under the action of external electric fieldElectric dipoleIt tends to be in a consistent arrangement, so that the macroscopic electric dipole moment is not equal to zero, which is called turning polarization.
be similar toSpringOscillatorVibrationPhenomenon (common light sources are all nonPolarity, such as:sunlight, lights and other natural light).Polarized lightIt is a kind of specialelectromagnetic wave, hisElectromagnetic oscillationIt only occurs in one direction, and the vibration in other directions is 0. Human eyes cannot distinguish whether light isPolarityOf.However, the eyes of some animals use the polarity of light to judge the route and migration (such as:honeybee）。
It is also easy to realize the polarization of ordinary light in the laboratory, such as a beam of light shooting at the interface,Reflected lightAndRefraction rayIt's all partPolarized light。Whenincident lightFrom a special angle（θ B）When firingReflected lightyesPolarized light, this corner is calledDeclination angleperhapsBrewster angleAt this time, the reflected light and the refracted light are perpendicular to each other.three-dimensionalThe glasses distributed by the cinema are also polarized films, which are perpendicular to each other.
Polarization mode
Announce
edit
That is, the vibration direction of the electromagnetic field. When the satellite transmits signals to the ground, the vibration direction of the radio wave can be in a variety of ways, including:
Horizontal polarization(H) : Horizontal polarization refers to the vibration direction of the radio wave is horizontal when the satellite transmits signals to the ground.
Vertical polarization (V): vertical polarization refers to the vibration direction of the radio wave is vertical when the satellite transmits signals to the ground.
Rock polarization
Announce
edit
Generally, substances areElectroneutralityIs positive or negativechargebalance.However, somerockandmineralUnder specific conditionsphysical chemistryUnder the process, rocks can formSurface chargeandVolume charge。This property of rock is calledRock polarization。
Cell polarization
Announce
edit
Cells are poor conductors. Both intracellular fluid inside the membrane and intercellular fluid outside the membrane areelectrolyteAnd conducting electricity.Because of transmembranepotentialIn the presence ofResting stateAtelectrical scienceThe model can be regarded as a closed surface with uniform distribution of negative and positive charges inside and outside the filmGalvanic layerAt this timepotentialIs zero.Cells in a resting state maintain normal metabolism,Resting potentialAlways stable at a certain level.For the whole cell, it is not sensitive to external electricity. At this time, the state of the cell is called polarization.
The following describes the commonly used vertical polarization (V) and horizontal linear polarization (H) reception methods.
Vertical polarization andHorizontal polarizationThe receiving of is to change the direction of the rectangular (rectangular) waveguide port of the feed to determine whether the receiving is vertical polarization or horizontal polarization.When the long side of the rectangular waveguide port is parallel to the ground, it receives vertical polarization, and when it is perpendicular to the ground, it receivesHorizontal polarization。Polarization direction(Polarization angle) also varies from place to place.Because the earth is a sphere, and the downlink beam of satellite signals is horizontal and straight, which results in different polarization signals received from different azimuth angles. Therefore, the polarization direction of the received signals is also different due to different geographical locations.Polarization mode
Polarization: VVertical polarization；HHorizontal polarizationThat is, the vibration direction of the electromagnetic field. When the satellite transmits signals to the ground, the vibration direction of the radio wave can be in a variety of ways, including:
Horizontal polarization (H): horizontal polarization refers to the vibration direction of the radio wave is horizontal when the satellite transmits signals to the ground.For example, if we take a rope and shake it to the left and right, the wave generated is left and right wave.
Vertical polarization (V): vertical polarization refers to the vibration direction of the radio wave is vertical when the satellite transmits signals to the ground.For example, when we take a rope and shake it up and down, the wave generated is up and down.
There are two types of polarization: linear polarization and circular polarization.The online polarization mode can be divided into horizontal polarization and vertical polarization;In circular polarization modeLeft-handed circular polarizationAnd right circular polarization.
social sciences
Announce
edit
Polarization;The unfair way of distribution has caused the gap between the rich and the poor to be too wide, and intensified contradictions among the people;
Some countries (such as the United States) are extremely democratic in some areas, while others (such as beliefs) use excessive regulation.
The economic development is extremely fast, the external image of the country is significantly improved, while the internal legal system construction is lagging behind, resulting in endless ugly phenomena in some fields, even overt hidden rules, which aroused the dissatisfaction of the people.
