简介:Theseaicecoverdisplaysvariousdynamicalcharacteristicssuchasbreakup,rafting,andridgingunderexternalforces.Tomodeltheicedynamicprocessaccurately,theeffectivenumericalmodelingmethodshouldbeestablished.Inthispaper,amodifiedparticle-in-cell(PIC)methodforseaicedynamicsisdevelopedcouplingthefinitedifference(FD)methodandsmoothedparticlehydrodynamics(SPH).Inthismethod,theicecoverisfirstdiscretizedintoaseriesofLagrangianiceparticleswhichhavetheirownsizes,thicknesses,concentrationsandvelocities.TheicethicknessandconcentrationatEuleriangridpositionsareobtainedbyinterpolationwiththeGaussianfunctionfromtheirsurroundingiceparticles.ThemomentumoficecoverissolvedwithFDapproachtoobtaintheEuleriancellvelocity,whichisusedtoestimatetheiceparticlevelocitywiththeGaussianfunctionalso.Thethicknessandconcentrationoficeparticlesareadjustedwithparticlemassdensityandsmoothlength,whichareadjustedwiththeredistributionoficeparticles.WiththeabovemodifiedPICmethod,numericalsimulationsforicemotioninanidealizedrectangularbasinandtheicedynamicsintheBohaiSeaarecarriedout.ThesesimulationsshowthatthismodifiedPICmethodisapplicabletoseaicedynamicssimulation.
简介:ItisnecessaryforanMC-CDMAuplinkreceivertoemployMUD(multiuserdetection)inafrequencyselectivefadingchannel.AfteranalyzingthealgorithmofPIC(parallelinterferencecancellation)MUD,anovelMUDscheme,Soft-PIC(softparallelinterferencecancellation)isproposed.Basedonthereliabilityofeachdetectedusersignalintheformerstage,thisSoft-PICdetectionschemesubstitutesasoftdecisionofthevariablefortheharddecisioninPICscheme.ComparedwiththePICscheme,itcanreconstructtheinterferencesignalsmoreaccuratelyandeliminateMAI(multipleaccessinterference)inamoreefficientway.PICisoneofthemostpracticalschemesinnumerousmultiuserdetectiontechnologies.However,Soft-PICasanimprovedPICschemedeservesfurtherstudy.
简介:因价格原因,廉价虚拟示波器存在数据采集速度慢、数据传输到计算机的速度慢、波形显示反应慢等瓶颈等问题。文章使用A/D转换芯片MAX1002实现模拟量的高速采集,使用USB单片机PIC18F4550实现数据的高速传输,使用DirectDraw技术解决显示速度慢问题。文章详细论述了系统的硬件与软件设计。
简介:摘要目的探讨脉冲式封管技术在预防导管堵塞的Power-pic护理干预。方法抽取2010年11月至2012年12月在我科就诊并接受置管治疗的Power-pic患者9例,其中有2例患者反复发生导管堵塞,对其护理措施进行观察及总结。结果脉冲式封管技术标准化维护可有效的预防导管堵塞。结论Power-pic导管堵塞的护理重在预防,加强导管维护知识的相关培训,达到脉冲式封管技术的三滴效应,才能有效的预防Power-pic导管堵塞,提高白血病患者Power-pic导管的留置效果。
简介:MicrochipTechnology(美国微芯科技公司)推出配备多种外设的通用闪存PIC单片机,有助于实现更具成本效益的风扇或小型电机控制。全新14引脚PIC16F616/610和8引脚PIC12F615/609单片机集成了多种专用外设,可大大减少系统所需的元件,降低成本。这些外设包括具有死区控制的全桥脉宽调制(PWM)、用于脉宽测量的Timerl门、霍尔效应传感器接口比较器,以及具有温度和其他监控功能的数/模转换器。同系列器件PIC16HV616/610和PIC12HV615/609增加了内置分流稳压器,使PIC单片机无需另加稳压器就可以在更高电压轨上运行。