简介:Theconfigurationandaerodynamicperformanceoftheinletsystemareimportantaspectsintheprocessofinstallingagasturbineonanavalvessel.Undertherequirements,largeeddysimulation(LES)isusedtosimulatethethree-dimensionalfluidflowinthewaveblockerofamarineinletfilter.TheSmagorinsky-Lillysub-gridmodelwasusedtomodelmotionsofsmall-scalestructures.Duringnumericalsimulation,theSIMPLEalgorithmwasapplied.Thecentral-differencingspatialdiscretizationschemeandthesecondorderaccuracyfinitedifferenceforthetemporaldiscretizationwereused.Simulationgivessatisfactorydistributionofthevorticityfieldsandturbulentkineticenergy.Comparedwiththek-εturbulentmodel,theresultsofLESarebetterforthedistributionofparameters.Theresultsofexperimentalstudyinasmall-scalewindtunnelindicatethatnumericalcalculationhashigheraccuracy.Therefore,themethodsusedareworthyofreferenceandintroductionforthedesignofaninletsystem.
简介:BackgroundClinicalapplicationofimplantablecardioverterdefibrillator(ICD)cansignificantlyreducetheincidenceofsuddencardiacdeath(SCD).However,ICDcannotpreventventriculartachycardia(VT)orventricularfibrillation(VF).PreviousstudiesindicatedthatICDcombinedwithreasonableanti-arrhythmicdrugtherapycanimproveanti-arrhythmiceffect.EMIAT,CAMIAandOPTICtrialsreportedthatcombinedtreatmentofAmiodaroneandβreceptorblockerswassuperiortotheirtreatmentalone.Therefore,itisnecessarytogiveanti-arrhythmictreatmentafterICDimplantation.MethodsTotally180ICDimplantationrecipientsenrolledinourhospitalfromJan2011toMarch2014.Amongthem,39recipientsweretreatedwithAmiodarone(GroupA),89recipientsweretreatedwithβblocker(GroupB),and52recipientsweretreatedwithAmiodaronecombinedwithβblocker(GroupC)afterICDimplantation.Patientswerefollowedupfor3to40monthsbymonitoringtheheartrate,LVEFValueandrapidventriculararrhythmiasevents.ResultsTherewerenosignificantdifferencesonheartratebeforeandafterICDimplantationamongthethreegroups(P=1.28,P=0.85),butthechangeofheartratewasstatisticallyhigher(P=0.04)inGroupBcomparedwithGroupAandGroupC.TherewerenostatisticalsignificanceinLVEFvaluebeforeICDimplantationandafterICDimplantationandthechangeofLVEFvalue(P=0.56,P=0.50,P=0.99).TheoccurrencerateofrapidventriculararrhythmiasinGroupA(10.26%)andGroupB(10.11%)wassignificantlyhigher(P=0.04)thaninGroupC(1.92%).whichwaeslightlyincreasedbyAmiodaroneinGroupAandGroupC.Therewere2casesofthyroiddysfunctioninGroupA,1caseinGroupCandnocaseinGroupB.Nopulmonaryinterstitialfibrosiscaseswerefoundinthisstudy.ConclusionsCombinedtreatmentwithAmiodaroneandβreceptorblockerscouldsignificantlyreducerapidventriculararrhythmiaswhencomparedwithtreatmentofAmiodaroneorβblockeralone.
简介:摘要目的观察醋酸钙联合低钙透析液对维持性血液透析(maintainhemodialysis,MHD)患者钙磷代谢的影响。方法选择贵阳市第一人民医院透析龄超过3个月,且血磷大于1.78mmol/L,血钙水平2.02~2.5mmol/L,血清钙磷乘积<55mg2/dl2,IPTH水平300~1000pg/ml的患者60例,随机分为两组,每组各30人。两组患者之前均未接受过正规骨化三醇冲击治疗,两组患者均未口服其他降磷及含钙药物。两组患者均予醋酸钙片1334mg(2片)口服,随餐嚼服,每日三次。A组透析液钙离子浓度为1.5mmol/L,B组透析液钙离子浓度为1.25mmol/L。根据患者IPTH水平同时给予骨化三醇冲击治疗。观察第15天、30天、45天、60天患者的血钙、血磷及IPTH水平。结果两组患者随着时间的延长,血磷及IPTH水平较治疗前有明显下降(P<0.05),A组患者血钙水平较治疗前有所升高(P>0.05),但差异不明显。B组患者血钙水平较治疗前无明显变化,B组的血钙水平较同期A组有所降低,但差异不明显(P>0.05)。结论醋酸钙可以显著降低MHD患者的血磷水平,但有导致高钙血症的风险,低钙透析液减少高钙血症的风险不明显。