简介：Airentrainmentisknowntobeoneofefficientandinexpensivemethodstopreventcavitationdamagesinhydropowerprojects.Theshapeofsuddenexpansion-fallisusedasacommondeviceformitigatingcavitationerosions.Thecomplexflowpatternswithcavitationarenumericallysimulatedbyusingtherealizablek-εturbulencemodelandtheair-watermixturemodel.Thecalculatedresultsarecomparedwellwiththeexperimentalresultsaswellasthoseobtainedwiththek-εturbulencemodelwiththeVolumeOfFluid(VOF)Model.Thecalculatedresultsagreewellwiththeexperimentaldatafortheaerationcavityandwallpressure.Moreover,theairconcentrationnearsidewallissimulatedbyamixturemodel.ItisfoundthatthemixtureturbulencemodelissuperiortotheVOFturbulencemodel.

简介：WestudythefeatureofmediachangesbeneaththeZipingpureservoiranddiscusstheprocessofpermeationwiththewaterlevelriseandfallofthereservoirfromJanuary2005toJanuary2008fromambientnoisecrosscorrelationbyusingcontinuousseismicdatarecordedbythestationsofZipingpuseismicnetworkandYZPstation.Amoving-windowcross-spectrumtechniquehasbeenusedtocalculatetherelativeseismicvelocitychangesbetweenstationpairs.Resultsrevealedanobviousrelationshipbetweenrelativeseismicvelocity,andthewaterlevelchangeswithatimedelaythatmaybecausedbypermeationduringthreemainimpoundmentsandtwolargescaledisemboguements.Impoundmentgeneratesafastandlargeimpactonthesuperficiallayer,andthechangesofseismicvelocityistheresultofincreasedpressureandpermeationduringtheimpoundment.Atthefirstimpoundment,themaineffectfactorispressure.Duringthenexttwoprocessofimpoundment,permeationbecomesthemaineffectfactor,affectingthefaultatadepthofabout8km.

简介：目的：研究电针逆转血管紧张素-（17）[Ang-（1—7）]在大鼠延髓尾端腹外侧区（CVLM）引起血压降低的作用机制。方法：采用中枢核团微量注射和微透析，以及高效液相色谱（HPLC）荧光检测等技术观察Ang（17）及其选择性受体拮抗剂（D-Ala7）-Ang-（1—7）（Ang-779）在大鼠CVLM引起血压改变时氨基酸类神经递质释放的变化以及电针对血压和氨基酸类递质释放的影响。结果：在CVLM微量注射Ang（1—7）可引起血压降低，同时伴该区内兴奋性氨基酸谷氨酸（Glu）释放增多和抑制性氨基酸牛磺酸（Trau）释放减少；相反，在CVLM微量注射Ang779则可引起血压升高，同时伴Glu释放减少和Tau释放增多。在相当于人”足三里”穴位电针20min，可分别抑制在CVLM微量注射Ang—（1-7）或Ang779所引起的血压降低或升高，同时也能部分抵消注射Ang-（17）或Ang779所引起的Glu、Tau释放的改变。结论：电针逆转Ang（1-7）或Ang-779在CVLM引起的降压或升压作用可能与Glu、Tau释放量的改变有关。

简介：Inordertotesttheaccuracyoftheusually-usedfixedcalibrationfactorofthecanopyscannerofLAI-2000formeasuringtheleafareaindex(LAI),aLarixprincipis-rupprechtiiplantationwaschoseninthesmallwatershedofXiangshuihelocatedattheLiupanMountainsofNingxiaHuiAutonomousRegionofNWChina,theLAIwasmeasuredinOctober2010,aperiodfromfullcanopytothetotalfallofneedles,byusingboththeLAI-2000andlitterfallcollectionmethod.Then,acomparisonwasmadebetweentheLAIvaluesdeterminedbythelitter-fallcollectionandthatcalculatedbasedonthefiguresreadfromLAI-2000andthefixedcalibrationfactor(1.49).ItshowedthattheaverageofLAImeasurementsofthe2methodswasveryclose,withadifferenceofonly5%.However,thecalculatedLAIfromLAI-2000wasobviouslyhigherthanthetruevaluesdeterminedbylitter-fallcollectionwhenthecanopywasfullofneedles;andobviouslylowerthanthetruevaluewhenthecanopywassparseafterneedlefalling.ThereasonmaybethatLAI-2000takestheprojectionoftwigsasneedles.So,adynamiccalibrationfactorisneeded,especiallyintheseasonswhentheneedleamountandthepercentageoftwigsprojectionincrownprojectionchangequickly.Therefore,astatisticrelationinaquadraticpolynomialformbetweenthe2seriesofLAIdatawaswellfitted.ThisrelationcanbeusedforamoreaccurateestimationofLAIbasedonthedatareadfromtheeasilyusedcanopyscannerslikeLAI-2000.

简介：美国女作家安妮·法迪曼在其获奖纪实文学作品TheSpiritCatchesYouandYouFallDown中以叙事者身份向美国社会讲述了她亲历的一桩苗族病人与美国医生在治疗方法上有巨大分歧的案例，由此引出苗族移居美国后面临的一系列社会问题。该作品在史学、人类学及医学三个领域都有深刻意义，这对国人了解当代海外苗族/Hmong人的生存状况具有重要意义。