简介：Anovellowpowerandlowvoltagecurrentmirrorwithaverylowcurrentcopyerrorispresentedandtheprincipleofitsoperationisdiscussed.Inthiscircuit,thegainboostingregulatedcascodeschemeisusedtoimprovetheoutputresistance,whileusinginverterasanamplifier.ThesimulationresultswithHSPICEinTSMC0.18umCMOStechnologyaregiven,whichverifythehighperformanceoftheproposedstructure.Simulationresultsshowaninputresistanceof0.014Ωandanoutputresistanceof3GΩ.Thecurrentcopyerrorisfavorableaslowas0.002%togetherwithaninput(theminimuminputvoltageofvin,min~0.24V)andanoutput(theminimumoutputvoltageofvout,min~0.16V)complianceswhileworkingwiththe1Vpowersupplyandthe50uAinputcurrent.Thecurrentcopyerrorisnearzeroattheinputcurrentof27uA.Itconsumesonly76uWandintroducesaverylowoutputoffsetcurrentof50pA.

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简介：Carbon-manganesesteelisoftenappliedincomponentsofpipesinnuclearplant.Ultrasonicfatiguetestsfollowinglowcyclefatigue(LCF)cyclesdamagedareusedtostudythestrengthofveryhighcyclefatigure(VHCF).ThecomparisonoftestresultsofsimpleVHCFandcumulativefatigue(LCFplusVHCF)showsthatLCFloadinfluencesthefollowingVHCFstrength.ContinuumdamagemechanicsmodelisextendedtoVHCFregion.TheeffectofLCFloadonVHCFisstudiedbyanimprovedcumulativedamagemodel.

简介：BasedontheopticaldatafortransmittedradiationthroughseaiceintheArcticduringthelateautumnandearlywinterof2007,theauthorsstudiedthearrivingsolarradiation,reflectedradiationandtransmittedradiationunderverylowsolaraltitude.Throughtheatmosphere,thelightofthearrivingsolarradiationatshortwavelengthwasweakened,withthespectraldistributionofdoublepeakscenteredat490nmand683nm.Themagnitudeofthepeakat683nmevenexceededthatat490nmundertheverylowsolarradiationcondition.Thereflectionwaslowerthanthatinsummertimebecauseofthethinthicknessesoficeandsnow,allowinghigherratioofheattoentertheseaiceandsnow.Whenhigherratioofsolarradiationenteredseaiceinlateautumn,thenewicefreezingwouldbeaffected.Thespectralreflectivityfromsnowsurfacewasalmostaconstant,butthereflectionwithoutsnowde-creasedatlongerwavelengths.Inthetransmissionspectrum,thelightof490nmwasdominant.Itindicatesthattheradiationatlongerwavelengthwasweakenedbyseaice.Therefore,undertheconditionoflowsolaraltitude,theradiationatshorterwavelengthwasweakenedbytheatmospherewhiletheradiationatlongerwavelengthwasweakenedbytheseaice.Thecombinedeffectofat-mosphereandseaicemadethesolarradiationunderseaicemuchweaker.Theabsorptionofseaiceforthelonger-wavelengthradiationallowedtheseaicetogainmoreheattoslowdownthefreezingprocess.

简介：Intheefforttodevelopacomprehensiveapproachtobetterandgoodjobs,itisatopicofhotdebateastowhethertheintroduction(temporarilyoronapermanentbasis)ofstatutorylegislation―differentfromthegenerallawapplyingtosubordinateworkers―mayencourageemployersandemployeestooperatewithintheformaleconomyandinthecontextofregularcontractsofemployment.Theessayanalyzesfromacomparativepointofviewnotthetraditionalformsofnon-standardemployment,butthosespecialworkingarrangements,thatmayinvolveveryshorthours(“marginal”parttime:generally,fewerthan15hoursperweek)ornopredictablefixedhours,andthoseaccordingtowhichtheemployerhasnoobligationtoprovideasetnumberofhoursofwork.Theconclusionisthatextremelyatypicalformsofworkappeartogiveananswertothechallengesofthemarketlaboroftheurbaneconomiesofthe21stcentury,butthatspeciallegalprovisionsareneededtoguaranteeindividualrighttofairwagesandtoprotectpersonallifeofemployees.

简介：X-raydiffractionmethodsforestimatingthemetamorphicgradeofdiagenetic,anchizoneandepizoneinmetapelitesarereviewedandappliedtosamplesfroma7000m+boreholeinwesternChinaandsurfacesamplesfromthesurroundingZoigêarea.Kübler'sillitecrystallinity(IC)measurementsprovidemoreconsistentresultsthancalculatedvaluesofpercentageofilliteintheI/SmixedlayersandpercentageofI/Smixedlayers.Down-boreholeICvaluesdisplayatypicalburialmetamorphicrelationshipbetweenstratigraphiclevelandIC.Amethodforpreparingverylowgrademetamorphicmapsisdescribed,andisogradsplottedonaregionalgeologicalmapatselectedvaluesofIC,delineatingahightemperaturediageneticzone,ananchizone,andanepizone.ThemapshowsthatICvaluesarecontrolledbystratigraphiclevelinthenorthofthestudyarea(i.e.burialmetamorphism),andproximitytoanigneousintrusivebodyinthesouth(i.e.contactmetamorphism).

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简介：Veryhighcyclefatigue(VHCF)propertiesofalowtemperaturetemperingbearingsteelGCr15withsmoothandhole-defectspecimensarestudiedbyemployingarotarybendingtestmachinewithfrequencyof52.5Hz.Bothsmoothandhole-defectspecimensbreakinVHCFregimewithsomedifferenceinfatiguecrackinitiation.Forsmoothspecimens,afinegranulararea(FGA)isobservednearthegrainboundaryinthefracturesurfaceofthespecimensbrokenafter10~7cycles.ButnoFGAisobservedinthehole-defectspecimensbrokeninVHCFregime,andtheVHCFcrackdoesnotinitiatefromthesmallholeatthesurfaceasitdoesatloworhighcyclefatigueregime.InternalstressisemployedtoexplaintheVHCFbehaviorofthesetwotypesofspecimens.Atlast,anadvanceddislocationmodelbasedonTanakaandMuramodelisproposedtoillustratetheinternalstressprocessandtopredictfatiguecrackinitiationlifewithFGAobservedinthefractureregion.

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简介：Aservocontrolsystemispronetolowspeedandunsteadinessduringvery-low-frequencyfollow-up.Adesignmethodoffeedforwardcontrolbasedonintelligentcontrollerisputfoward.Simulationandtestresultsshowthatthemethodhasexcellentcontrolcharacteristicsandstrongrobustness,whichmeetstheservocontrolneedswithvery-lowfrequency.

简介：Amodelisproposedtocorrelatethecrackgrowthrateandstressratiocontainingveryhighcyclefatigueregime.Themodelisverifiedbytheexperimentaldatainliterature.Thenaformulaisderivedfortheeffectofmeanstressonfatiguestrength,anditisusedtoestimatethefatiguestrengthofabearingsteelinveryhighcyclefatigueregimeatdifferentstressratios.TheestimatedresultsarealsocomparedwiththosebyGoodmanformula.

简介：Veryhighcyclefatiguebehaviorsoftwobainite/martensitedual-phasesteelswereinvestigated.Oneofthesteelswascyclicrapidheattreatedanditsmicrostructureswererefined.Fatiguestrengthofthesteelis225MPahigherthanthatwithoutrefining.Observationoffracturesurfacesshowthatthefatiguecracksinitiateatbainitesfornon-refinedsteelandatnon-metallicinclusionsfortherefinedsteel.Thesizeofinclusionsismuchsmallerthanthatofbainiteswhichresultsintheimprovementoffatiguestrength.

简介：AbstractIntroduction:Portal venous gas (PVG) is common in necrotizing enterocolitis and occasionally occurs in neonates after umbilical vein catheterization (UVC). Therefore, determining the cause of PVG requires further clinical evaluation in these cases.Case presentation:We report the case of a very-low-birth-weight infant who underwent UVC after birth. PVG was an unexpected finding on ultrasound following catheterization. The UVC was immediately removed and replaced with a peripherally inserted central catheter. The infant’s physical examination was unremarkable. Bedside X-ray revealed neither PVG nor pneumatosis intestinalis, which would indicate the onset of necrotizing enterocolitis. After full evaluation, breastfeeding was started on the same day. The infant did not develop feeding intolerance, necrotizing enterocolitis, or other disorders.Conclusion:PVG occasionally occurs in neonates who undergo UVC and is considered to be caused by exogenous gases. PVG is more easily detected with ultrasound than with X-ray and does not affect early feeding in premature infants.

简介：BACKGROUND:ItisknownthatacupuncturetherapycandecreaseplasmaneuropeptideY(NPY)levelsinpatientswithcerebralinfarction,butdifferenttypesofacupuncturetherapyusedinvariousstagesofcerebralinfarctionhavenotbeenevaluated.OBJECTIVE:Toexploretheeffectofacupuncturetherapyonresuscitation(XingnaoKaiqiao)andplasmaNPYlevelsinpatientswithveryearlystageacutecerebralinfarction.DESIGN,TIMEANDSETTING:Thiscase-controlledstudywasperformedattheAffiliatedHospitaloftheMedicalCollegeoftheChinesePeople'sArmedPoliceForcebetweenSeptember2004andOctober2005.PARTICIPANTS:Sixtypatientswithacutecerebralinfarctionof≤6hourswereusedinthisstudy.Patientswererandomlydividedintoanacupuncturetherapygroup(n=30)andaroutinetreatmentgroup(n=30).Another30healthysubjectswereusedasthecontrolgroup.METHODS:TheacupuncturetherapyofXingnaoKaiqiaousedintheacupuncturetherapygroupwasbasedonroutinewesternmedicaltreatmentandwasperformedatbilateralNeiguan(PC6)usingthetwirling,reinforcing-reducingmethod,Renzhong(DU26)usingheavybird-peckingneedling,Sanyinjiao(SP6)usingreinforcingandreducingbyliftingandthrustingtheneedle,Jiquan(HT1),Weizhong(BL40)andChize(LU5)usingreinforcingandreducingbyliftingandthrustingtheneedle.Theacupuncturelastedfor14days.Patientsintheroutinetreatmentgroupunderwentroutinemedicaltreatmentandnointerventionwasgiventosubjectsinthecontrolgroup.MAINOUTCOMEMEASURES:A4mLvenousbloodsamplewasobtainedatdifferenttimepoints,i.e.,immediatelyafterhospitalization,thenextmorning,7and14daysaftertreatment,tomeasureplasmaNPYlevelspre-andpost-treatmentusingtheradio-immunitymethod.RESULTS:TheplasmaNPYlevelsweresignificantlyhigherinboththeroutinetreatmentgroupandtheacupuncturetherapygroupthaninthecontrolgrouppre-andpost-treatment(P<0.01).Inparticular,theplasmaNPYlevelsinboththeacupuncturetherapygroupa

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简介：Wereportontheamplificationofhigh-average-powerandhigh-efficiencypicosecondpulsesinaself-madeverylarge-mode-areaYb-dopedphotoniccrystalfiber(PCF).ThePCFwithacorediameterof105μmandacorenumericalapertureof0.05ispreparedbythesol-gelmethodcombinedwiththepowdersinteringtechnique.Thefiberamplificationsystemproducesthehighestaveragepowerof255Wata10MHzrepetitionratewitha21pspulsedurationcorrespondingtoapeakpowerof1.2MW.Thisresultexemplifiesthehigh-average-powerandhigh-peak-powerpotentialofthisspecificallydesignedfiber.

简介：一、设计理念1．创设真实、直观的语言情景，帮助学生理解所学语言。2．设计学生喜欢的活动，培养其学习英语的兴趣。二、教学目标1．知识目标（1）能听瞳、会说、会读、会拼写单词shy，loud，quiet，nice。（2）能听懂、会说、会读短语helppeople，makee-cards。