压电性能英文

PHA.. 1. 植物血凝素近10年的研究表明：牙周病与免疫功能密切相关，用单克陛抗体CD系列，可以了解牙周炎患者细胞免疫状态．植物血凝素(PHA)是一种非特异抗原刺激物，能刺激T淋巴细胞转化，检测其转化功能，可以更全面了解青少年牙周炎的细胞免疫功能。

在压电晶体上施加压力，晶体发生极化，两端带电。可逆，当在晶体上施加电场时，晶体发生形变，称为逆压电效应，又称为电致伸缩。

The piezoelectric effect as early as discovered in 1880, by no meansbrings to people's attention at first in during several dozens years,the First World War period, because surveys technical the and so onnaval vessel and sunken wreck demand, western some countries havelaunched some research to the piezoelectric crystal practicaltechnology, but has not still obtained the widespread applicationuntil the 20th century 30's, after two world wars, the newpiezoelectricity ceramic material developed successfully only thencauses the piezoelectricity ceramics the application to open the newpage, has obtained the universal application to the present. We maysee: Any physical effect from discovered all must experience a quitelong time to the application The new material appearance is thephysical effect can the widespread application foundation, each kindof new technical demand is the physical effect can the applicationpromoter. By physics knowledge, some ion crystals dielectric media (for examplequartz, potassium tartrate sodium, barium titanate and so on) not onlyunder electrical field intensity function, moreover under themechanical power function, can have the phenomenon of polarization.Namely: Exerts when in these dielectric media certain directions themechanical power has the distortion, can cause its interior positiveand negative electric charge center relative shift to have theelectricity polarization, thus causes its two relative surfaces(极化面) on to appear the mark opposite bound charge, also itselectric displacement D (in MKS 单位制 center is electric-chargedensity sigma) has the direct ratio with external stress tensor T;When the external force vanishes, also restores not the chargedoriginal condition; When the external force changes to, the electriccharge polarity changes along with it. This kind of phenomenon iscalled the piezoelectric effect, or abbreviation piezoelectric effect. If exerts the pressure to the piezoelectricity material, it then canhave the potential difference (to call it piezoelectric effect),otherwise exerts the voltage, then has the mechanical stress (to becalled counter piezoelectric effect). If the pressure is one kind ofhigh frequency vibration, then produces is the high-frequency current.But the high frequency electrical signal adds when thepiezoelectricity ceramics, then produces the high frequency soundsignal (machinery to vibrate), this is the ultrasonic wave signalwhich we usually said. In other words, the piezoelectricity ceramicshave between the mechanical energy and the electrical energytransformation and the counter transformation function experimentproved that, every has the piezoelectric effect the crystal, alsocertainly has the counter piezoelectric effect. Now the piezoelectric effect also applies on the polycrystal, forinstance the present piezoelectricity ceramics, including the bariumtitanate piezoelectricity ceramics, PZT, the niobate are thepiezoelectricity ceramics, niobium magnesium sour leadpiezoelectricity ceramics and so on. When you when light the coal gasstove or the water heater, had one piezoelectricity ceramics quietlyto serve for you. Produces the factory in this kind ofpiezoelectricity firing device, is hiding together thepiezoelectricity ceramics, when the user presses down the firingdevice the spring, the transmission device on exerts the pressure onthe piezoelectricity ceramics, causes it to produce the very highvoltage, then courses the electrical energy the fuel gas theexportation electric discharge, thereupon, the fuel gas on was lit bythe electric spark Crystal crystal when not stress, its positive charge center and thenegative charge center superposition, the entire crystal totalelectricity is rectangular is zero, the crystal plane not charged,when crystal stress, causes the positive and negative electric chargecenter as a result of the deformation no longer to superpose, crystalbeginnings and ends surface charged, this kind of positive andnegative electric charge center does not superpose the phenomenon iscalled the polarization Also has the minority piezoelectric crystalas a result of itself interior special structure, in outside in theelectric field situation has not had the phenomenon of polarization,such polarization for spontaneous polarization This kind hasspontaneous polarized in the crystal to have some spontaneouspolarized orientation consistent small regions, is called 电畴After it is put in the electric field, the original stochastic chaoticorientation 电畴 can along the electric field direction orientation,if electric field again reverse, spontaneously polarizes the unit alsoto be able with to be reverse, its polarized and the electric fieldrelations are a return wire, calls it the dielectric hysteresis returnwire, with ferromagnet hysteresis loop shape similar, therefore thepeople 类晶体 are called this the ferroelectricity body (actuallyin crystal certainly not to include iron), this return wire is theferroelectricity body symbol Obviously, the ferroelectricity body isin the piezoelectricity body one kind. In the nature has the piezoelectric effect the piezoelectric crystalto be very many, but often will become the ceramic material later notto present the piezoelectricity performance, this mainly will bebecause the ceramics will be one kind of polycrystal, as a result ofeach tiny crystal grain disorder orientation, thus each intergranularpiezoelectric effect will be able mutually to counterbalance,macroscopic will not present the piezoelectric effect. In theferroelectric ceramics although has the spontaneous polarization, buteach intergranular spontaneous polarization direction is disorderlytherefore macroscopic 无极 nature. If passes through in advance theferroelectric ceramics the strong direct-current field function,causes various crystal grains the spontaneous polarization directionall according to qualification orientation to become has the rule thearrangement (this process to be called artificial polarization), after当直 flows the electric field to remove, in the ceramics still couldretain the suitable surplus polarization intensity, then the ceramicmaterial macroscopic had the polarity, also had the piezoelectricityperformance. Therefore, the ferroelectric ceramics only have process" Polarizes " Processing, the ability has thepiezoelectricity. The piezoelectricity ceramics generally are theferroelectricity body, only has the ferroelectric ceramics to be ableunder the outfield function, causes the spontaneous polarized unitmovement to change, achieves " Polarizes " The goal, becomesthe piezoelectricity ceramics, thus is called this kind of ceramicsthe ferroelectricity, the piezoelectricity ceramics.

Press to give or get an electric shock the effect to discover for as early as 1880, at at the beginning several 10-year did not cause the people's value, period of World War I, because of probing into the warship boat and sinking the technical need of etc. of ship, western and some nations launch some researches towards pressing the practical technique of the transistor, but World War II later, new press to give or get an electric shock the porcelain and ceramics material to research to manufacture success did not made press the electricity the application of the porcelain and ceramics to uncover new one page until 30's in 20 centuries not yet gets extensive application, acquiring the widespread pplication to now.From medium we can see:Any physics effect from discover that the applications all want to experience a very long period.The emergence of the new material is the foundation that the physics effect can apply extensively, various new technical need is the physics effect can apply of accelerant. Know from the physics, the electricity of a crystal of some ion lies the quality( such as sour barium of quartz, tartaric acid potassium 钠 , 钛 etc.) not only under the electric field dint function, and under the machine dint function, will produce the pole to turn the phenomenon.Namely:At these electricities lie the certain direction of the quality to transform up the infliction machine dint but creation, will cause it internal just the negative charge center is opposite to transfer but produce the electricity to turn very much, thus causing it two opposite surface( turn the noodles very much) up appear the contrary tie electric charge of sign, and its electric potential move the D( in the unit of MKS system namely the charge density σ ) with the outside should dint ZHANG LIANG2 T becomes the direct proportion; be the outside dint disappearance, again the instauration does not take to give or get an electric shock the original shape;When the outside dint change to, the electric charge pole immediately but change.This kind of phenomenon be called just press to give or get an electric shock the effect, or the brief name press to give or get an electric shock the effect. If give or get an electric shock the material to bring pressure towards press, it will produce the potential difference( call it as just press to give or get an electric shock the effect) then, whereas the infliction electric voltage, then produce the machine in response to the dint.( be called to go against to press to give or get an electric shock the effect)If the pressure is a kind of high 频 to vibrate, then output is a high electric current of 频 .But the high 频 telecommunication number imposes to press to give or get an electric shock the porcelain and ceramics up, then produce a signal( the machine vibrate) of high 频 , this is a signal that we say usually.Also is to say, the function experiment certificate that press to give or get an electric shock the porcelain and ceramics to have the machine ability and conversion between electric powers and converse to change, any have just press to give or get an electric shock the effect of crystal, also certainly have to go against to press to give or get an electric shock the effect. Press to give or get an electric shock the effect now also applied on many crystals, press to give or get an electric shock the porcelain and ceramics now for example, include the sour barium of 钛 to press to give or get an electric shock the sour salt of porcelain and ceramics, PZT, 铌 the department presses to give or get an electric shock the sour lead of porcelain and ceramics, magnesium of 铌 to press to give or get an electric shock the porcelain and ceramics etc..When you are sparking the coal gas cooking stove or water- heaters, there will be a kind of press to give or get an electric shock the porcelain and ceramics to have already served for you silently once.Produce the factory house in this type ofly press give or get an electric shock lighting the fire device, hide a cake of to press to give or get an electric shock the porcelain and ceramics, be the spring coil that the customer presses some fire device, spread to move to equip the pressure infliction in pressing to give or get an electric shock the porcelain and ceramics, make it produce the very high electric voltage, then turning on electricity the exit that the electric power leads to annoy toward燃 , hence, the 燃 annoy drive gave or get an electric shock the spark to spark. The crystal crystal while be free from dint, its positive charge center and the negative charge center are heavy to match, the total electricity 矩 of the whole crystal is zero, the crystal surface does not take the electricity, being the crystal to be subjected to the dint, because the form no longer change but cause the positive negative charge center heavy match, the crystal both ends surface took to give or get an electric shock, the phenomenon that this kind of positive negative charge center is not heavy to match is called the pole to turn.Also have the minority to press the transistor because of oneself the special structure of the inner part, exist to turn the phenomenon very much under the condition of have no dispatches from foreign news agency field, change into very much thus self-moving turn very much.This kind of have self-moving turn very much of exist in the crystal some self-moving turn the consistently small district of mindset very much, be called the electricity 畴 .It was put into electric field after, the electricity 畴 of the originally random confusion mindset will follow the electric field direction mindset, if electric field again anti- to, self-moving turn the unit very much and also will come after anti- to, it turn very much with the relation of the electric field is a the root return to line, calling it as to give or get an electric shock the 滞 to return to line, returning to the line shape with the 磁滞 of the body of iron 磁 similar, so the people are called the iron electricity body( in fact in the crystal not imply the iron) to this crystal, this return to line is an iron to give or get an electric shock the body of marking.Obviously, the iron electricity body is to press to give or get an electric shock a kind in the body. It have to press to give or get an electric shock the effect to press the transistor in the nature a lot of, but usually become the porcelain and ceramics material hereafter does not present to press to give or get an electric shock the function, this mainly is because the porcelain and ceramics is a kind of many crystal, because of among them each mess mindset of small grain of 晶 , as a result the each 晶 grain press to give or get an electric shock the effect and will cancel out each other, the macro view does not present to press to give or get an electric shock the effect.In the iron electricity porcelain and ceramics although exist self-moving turn very much, an of each 晶 is self-moving to turn the miscellaneous confusion of direction very much therefore macroscopic limitless.If give or get an electric shock iron porcelain and ceramics in advance after the strong direct current electric field function, make each of self-moving turn the alignment( this process is called the artificial to turn very much) that the directions all choose the excellent mindset to become the regularity very much, be the direct current electric field to do away with, porcelain and ceramics inside still can reserve the equal surplus to turn the strength very much, then the porcelain and ceramics material macro view has the pole, also having to press to give or get an electric shock the function.Therefore, the iron electricity porcelain and ceramics onlies have the process" turn very much" to handle, the ability presses to give or get an electric shock sex.Press to give or get an electric shock the porcelain and ceramics is the iron electricity body generally, only the iron electricity porcelain and ceramics then can make under the outfield function self-moving turn the unit sport to change direction very much, attain the purpose of" turn very much", become press to give or get an electric shock the porcelain and ceramics, as a result be called the electricity of iron to this porcelain and ceramics and press to give or get an electric shock the porcelain and ceramics.