向列相液晶電流體動力不穩(wěn)定性導(dǎo)電方式區(qū)的研究.pdf

1、河北工業(yè)大學(xué)碩士學(xué)位論文向列相液晶電流體動力不穩(wěn)定性導(dǎo)電方式區(qū)的研究姓名：劉麗媛申請學(xué)位級別：碩士專業(yè)：理論物理指導(dǎo)教師：張志東201012向列相液晶電流體動力不穩(wěn)定性導(dǎo)電方式區(qū)的研究iiTHESTUDYFELECTROHYDRODYNAMICCONVECTIONOFCONDUCTIONREGIMEINANEMATICLIQUIDCRYSTALABSTRACTElectrohydrodynamicconvection(EHC)ofnem

2、aticliquidcrystalsisawellsuitedsystemtostudypatternfmationinanisotropicfluids.Itisdrivenelectricallyyieldsalargevarietyofspatiallyextendedpatternswithdifferentdynamics.EHCincalamitic(rodlike)nematicliquidcrystalhasbeenst

3、udiedexperimentallyfalongtime.Williamsdomainsinnematicsrepresentoneofthestardsystemsfdissipativepatternfmationinanisotropicfluidstheyhavebeenextensivelystudiedinthepastdecades.Theclassicalelectrohydrodynamicconvection(EH

4、C)structuresobservedfirstbyWilliamsKapustinrollswithawavevectparallelslightlyobliquetothedirecteasyaxisinplanarswichcells.Theydestabilizetheunifmdirectgroundstateinnematicswithpositiveconductivityanisotropya?negativeweak

5、lypositivedielectricanisotropya?.Thefmermaybedesignatedas????，thelatteras????materialswherethefirstsignreferstoa?thesecondtoa?.The“stardEHC”mechanismhasbeenderivedbyCarrHelfrich.Lateradiscriminationofthesocalledconductio

6、ndielectricregimesunderacexcitationhasbeenintroduced.Innovelliquidcrystalmaterialswithunconvectionalmaterialparametersnewtypesofelectroconvectionpatternshavebeenfound.SomeofthemcanbeexplainedbytheCarrHelfricheffectwhileo

7、therstructurerequiremodificationsextensions.Themesogenstudiedinthepresentpublicationisabentcecompoundwithpositivea?negativea?????.InplanaralignmentitdevelopsunconventionalelectroconvectionpatternsabovethesplayFreedericks

8、ztransitione.g.longitudinalrollsthatareientedparallelnearlyparalleltotheinitialdirection0n???(fadeionoftheFreedericksztransition).Thisisincontrasttotheclassicalnmalrollswithanientationperpendicularto0n???inthe????caseina