简介：Electro-sparkdepositionhasbeencarriedoutonthe35CrMosteelbyfillingandrestoringthesimulatedslotspecimens,andcontinuoussurfacecoatingwithextralowporositywasobtainedwithproperparameters.Themicrostructuretransformationandinterfacebehaviorofdepositedjointwereobservedandanalyzed.Itshowsthatatransitionregionwith15μmindepthwasobtainedbetweenbasemetalanddepositedmetal,andmetallurgicalbondingwasachievedbetweenrestoredbasemetalanddepositioncoating.

简介：OnthebasisofdatacollectedintheJiaozhouBayinJuneandJuly2003,theDICdistributioninseawaterisstudied,andanaverageair-seafluxofCO2isestimated.TheresultsshowthatthecontentofDICinsidethebayismarkedlyhigherthanoutsidethebayinJune,butthecontentofDICoutsidethebayismarkedlyhigherthaninsidethebayinJuly.ThetrendofDICdistributioninsidethebayissimilar,viz.thecontentisthemaximuminthenortheast,thendecreasesgraduallytowardthewest,andthecontentistheminimuminthewest.Thetotaltrendofverticaldistributionistoincreasegraduallyfromsurfacetobottom.ThischaracteristicofDICdistributionisdeterminedbyJiaozhouBayhydrologyandthereisacloserelationbetweenDICandparticulateN,P.AverageCO2fluxacrossthesourceforatmosphericCO2inJuneandJuly,andthetotalCO2fluxfromseawaterintoatmosphereisabout740tinJuneand969tinJuly.

简介：Foracompression-shearmixedmodeinterfacecrack,itisdifficulttosolvethestressandstrainfieldsconsideringthematerialviscosity,thecrack-tipsingularity,thefrictionaleffect,andthemixedloadinglevel.Inthispaper,amechanicalmodelofthedynamicpropagationinterfacecrackforthecompression-shearmixedmodeisproposedusinganelastic-viscoplasticconstitutivemodel.Thegoverningequationsofpropagationcrackinterfaceatthecrack-tiparegiven.Thenumericalanalysisisperformedfortheinterfacecrackofthecompression-shearmixedmodebyintroducingadisplacementfunctionandsomeboundaryconditions.Thedistributedregularitiesofstressfieldoftheinterfacecrack-tiparediscussedwithseveralspecialparameters.Thefinalresultsshowthattheviscosityeffectandthefrictionalcontacteffectonthecracksurfaceandthemixed-loadparameterareimportantfactorsinstudyingthemixedmodeinterfacecracktipfields.Thesefieldsarecontrolledbytheviscositycoefficient,theMachnumber,andthesingularityexponent.

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简介：SurfacesedimentsamplestakenfromtheEastChinaSeaofftheChangjiangestuaryareusedasrawmaterialsforphosphorusreleasingexperiment.Itisfoundthatafterbeingthoroughlymixedwithseawaterforabout10minutes,phosphorusreleasedfromthesedimentsreachesitsmaximumvalue.AdsorptionkineticscanbefittedwithbothElovichequationandtwo-constantrateequation.Thereleasingamountiscloselyrelatedtothecompositionofthesediments.Phosphorusreleasefromsiltyandmuddysedimentishigherthanfromthatdominatedbysandycomposition.Forthedesorptionreaction,iron-phosphorus(Fe-P)isthemostactiveone,withareleasingratiohigherthanotherphosphorusforms,followedbyabsorbed-phosphorus(Ad-P)andorganicboundphosphorus(OP).Allofthemcanbereferredtoasbio-availablephosphorus.Theresultsdemonstratethatphosphorusinsedimentscanbereleasedintoseawaterundersuitablehydrodynamicconditions,andhaveagreatimpactonthenutritionstateandprimaryproductivityofmarinebiosphere.

简介：InordertosuppressthesurfacecrackinginducedbyCuduringreheatingandhotrollingprocess,Cuenrichmentanditsmigrationatthesteel-scaleinterfacewasinvestigatedduringheatingofsteelcastattemperaturesbetween1000℃and1200℃inN2-O2andN7-H2Oatmospheres.ForoxidationofCucontainingsteel,CuenrichedphasewasformedbythepreferentialoxidationofFeandtheenrichmentandmigrationbehaviorofCudependsontheoxidationtemperature,steelchemistryandatmospherecondition.NiinsteelinducedtheformationofsolidCuandNienrichedphaseatsteel/scaleinterfaceandinscalelayerandtheformationofunevensteel/scaleinterface,whichsuppressestheCuenrichmentbecauseofextrusionofCuenrichedregionbeforetheformationofliquidphase.Ontheotherhand,SnadditionpromotestheliquidCuformationatsteel/scaleinterfaceandpenetrationintograinboundaryofCuenrichedphasebydecreasingsolidustemperatureandsolubilitylimit.Inaddition,foroxidationat1200℃,thebehaviorofCuatandaroundthesteel-scaleinterfacewasfounddependenttoalargeextentonmorphologyoftheoxidescaleformedduringoxidation.Attheearlystageofoxidation,Cu-richphaseformedandaccumulatedatthesteelscaleinterfaceunderbothO2-N2andH2O-N2atmospheres.Astheoxidationproceeded,however,Cuenrichmentatanditsmigrationfromthesteel-scaleinterfacewerevastlydifferentfordifferentoxidizingatmospheres.InthecaseofO2-N2oxidation,anoxidelayerformedinitiallyatthesteelsurface,butsoonafteragapwasdevelopedatthesteel-scaleinterfaceandgrewinitssize,whichpracticallyseparatedthescalefromthesteelsubstrate.Thescalelayerformedunderthisconditionwasporous.TheCu-richphaseinitiallyformedattheinterfacewasfoundmigratingtothescalelayer,leavingnoCu-richphaseattheinterface.InthecaseofH2O-N2oxidation,however,thescalelayerformedwasdenseandtightlyattachedtothesteelsurface,andtheCurich-phasecontinuedto

简介：在坚硬地在任意的角度连接的二个无限的盘子的角落接口的颤动精力传播被波浪途径学习以便调查堵住使用减少把波浪传播弄弯的飞机的质量的效果。二个本地坐标系统被介绍，暗示管理盘子的典型阻抗或堵住质量的相应比率的六个新非维的系数被介绍简化传播和思考系数的明确的表达。五件样品在experiment.Discussions被测试以插入损失基于在预言和实验之间的比较被执行。在角落接口堵住质量象“一个lowpass过滤器”一样行动，这被结束，为在某些频率上面的颤动变细有效。在“变细乐队”的TL和IL的价值每每统一一些堵住的团在惯性的集体时刻统一“变细乐队”的长度和乐队宽度主要取决于质量。

简介：Acompositebeamissymmetricifboththematerialpropertyandsupportaresymmetricwithrespecttothemiddlepoint.Inordertostudythefreevibrationperformanceofthesymmetriccompositebeamswithdifferentcomplexnonsmooth/discontinuousinterfaces,wedevelopanR(x)-orthonormaltheory,whereR(x)isanintegrableflexuralrigidityfunction.TheR(x)-orthonormalbasesinthelinearspaceofboundaryfunctionsareconstructed,ofwhichthesecond-orderderivativesoftheboundaryfunctionsareaskedtobeorthonormalwithrespecttotheweightfunctionR(x).WhenthevibrationmodesofthesymmetriccompositebeamareexpressedintermsoftheR(x)-orthonormalbaseswecanderiveaneigenvalueproblemendowedwithaspecialstructureofthecoefficientmatrixA:=[aij],aij=0ifi+jisodd.Basedonthespecialstructurewecanprovetwonewtheorems,whichindicatethatthecharacteristicequationofAcanbedecomposedintotheproductofthecharacteristicequationsoftwosub-matriceswithdimensionshalflower.Hence,wecansequentiallysolvethenaturalfrequenciesinclosed-formowingtothespecialtyofA.Weusethispowerfulnewtheorytoanalyzethefreevibrationperformanceandthevibrationmodesofsymmetriccompositebeamswiththreedifferentinterfaces.

简介：Overcasting是过去常生产铝(固体)的一种新有点不一样的加入技术结合的/magnesium(液体)在这研究的二金属的材料。为Al/Mg(A390/AM60)二金属的样品，接口微观结构是研究点，它直接影响机械性质。因此，发现一个方法改进接口微观结构具有重要重要性。这研究在二金属的样品的A390/AM60接口微观结构上在液体Mg合金和热处理在钙(Ca)的效果上集中了增加。严峻的结果证明与在AM60的Ca增加，由于二个可能的原因，接口微观结构和A390/AM60二金属的样品的shear力量能被改进。热处理能进一步由溶解-Mg17Al12进-Mg并且破坏Mg2Si层结构。

简介：Blendbasedpolymernanocomposites,comprisingJanusnanoparticlesattheirpolymer/polymerinterface,wereanalytically/experimentallyevaluated.Themodelingprocedurewasperformedintwostages:first,modelingofpolymer/polymerinterfaceregioncomprisingJanusnanoparticlesandsecond,modelingoftheentiresystemsasafunctionofthevariationoftheblendmorphology.Inthefirststage,themodelingprocedurewasperformedbasedonthedevelopmentofthemodelproposedbyJietal.andinthesecondstage,thefundamentalofKolarik’smodelwasusedinordertoproposeadevelopedandmorepracticalmodel.ItwasshownthatJanusnanoparticlesmayformdualpolymer/particleinterphaseatpolymer/polymerinterfacewhichcandrasticallyaffectthefinalmechanicalpropertiesofthesystem.Comparingtheresultsoftensiletestsimposedondifferentpreparedsampleswiththepredictionsofthemodelproveditsaccuracyandreliability(error<9%).

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简介：AbstractObjective:To assess the value of magnetic resonance imaging (MRI) in fetal lateral ventriculomegaly diagnosed with ultrasound, and to study the relationship between the degree of isolated lateral ventriculomegaly and neonatal prognosis.Methods:The pregnancy information and outcomes of 97 cases of fetal ventriculomegaly were retrospectively reviewed in the Tianjin Central Hospital of Gynecology Obstetrics from January 2016 to December 2017. The maternal age was 18-42 years, and the fetal gestational age at diagnosis was 19+4 to 37+3 weeks. MRI and ultrasound were used to compared the diagnosis of fetal lateral ventriculomegaly and evaluated the development of the nervous system after birth.Results:Among 97 pregnancy cases, associated central nervous system malformations were observed in 36 cases on ultrasound or ultrasound + MRI. Central nervous system malformations were diagnosed with ultrasound in 15 cases (15/36, 41.7%) and with ultrasound + MRI in 25 cases (25/36, 69.4%). Pearson χ2 test was used to compare the detection rates between the groups, and the difference was statistically significant (P < 0.05). We followed up 61 cases of isolated lateral ventriculomegaly for 1-3 years after birth. According to the width of the lateral ventricle of the fetus in middle pregnancy, the subjects were grouped as follows: mild 33 cases (lateral ventricle width 10.0-12.0 mm), moderate 23 cases (lateral ventricle width 12.1-15.0 mm), and severe 5 cases (lateral ventricle width >15.0 mm). The rate of normal growth and development in the mild group was 90.9% (30/33), that in the moderate group was 69.6% (16/23), and that in the severe group was 40.0% (2/5), and the difference between groups was statistically significant (P < 0.05).Conclusion:Ultrasound combined with MRI can detect more central nervous system malformations, and the degree of isolated lateral ventriculomegaly is closely related to fetal prognosis.

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简介：Duetotheminiaturizationofmoderndevicesre-quirecomponentswithlightweight,highintegra-tionandtheabilitytostoreenergyinassmallvol-umeaspossible.Asaresult,energystoragedensitybecomesanimportantfigureofmeritforenergystor-agedevices.Inthispaper,firstly,wediscussedtheenergydensityinfine-grainedleadzirconatetita-nateglass-ceramicscompositewiththehelpofthe

简介：在为技术建模的脑电图(EEG)，数据片断选择是首先并且仍然重要的步。在一个基于EEG的大脑计算机接口(BCI)的特征抽取和分类上的一套data-segment-related参数的影响被学习。一个汽车搜索算法被开发在12题目EEG的每试用学习四个data-segment-related参数。数据片断(LDS)的长度，数据(SPD)的开始位置试用(NT)的片断，AR顺序，和数字被用来造模型。学习证明与没有参数选择的分类比率(CR)相比，CR被20%～30%与这些data-segment-related参数的合适的选择增加，并且最佳参数值是易于依赖者的。当为BCI造模型时，这建议data-segment-related参数应该被有个性。

简介：Thecalcareousfluvo-aquicsoilwascollectedandamicrocosmstudywascarriedoutwithroot-matandfrozenslicingmethodinlaboratory.ThepHintheroot-soilinterfacewiththecontroltreatmentwasjustslightlylowerthaninthebulksoil.However,theadditionofNH4--NsignificantlydecreasedthepHvalueintheroot-soilinterfaceandtheadditionofNo3-NslightlyincreasedthepHvalueintheroot-soilinterface.ThemagnitudeofpHchangesintheroot-soilinterfacedependedupontheconcentrationsofthenitrogensourcesadded.ThecontentsofCa2-P,Fe-PandAl-Pintheroot-soilinterfaceweremuchloweraftertreatedwithNH4-NandslightlyhigheraftertreatedwithNo3-Ncomparedwithcontroltreatment.Aftertreatedwith100,200and400mg·kg-1NH4+-N,thedeficiencyratesofCa2-Pinthearea0-1mmfromtherootplanewere37.1%,45.9%and57.7%,respectively,thedeficiencyratesofFe-Pwere23.4%,29.1%and38.2%,respectively,andthedeficiencyratesofAl-Pwere25.1%,28.0%and33.2%,respectively.ComparedwiththecontrolthedeficiencyratesofCa8-PinNH4+-NandNo3-Ntreatmentsdecreasedandincreased,respectively,butthedifferenceswerenotobvious.ThecontentsofCa10-PandO-Pintheroot-soilinterfacedidnotsignificantlychangeaftertreatedwithNH4+-NorNo3-N,suggestingthatCa10-PandO-PwereremarkablydifficulttobemobilizedevenatthepresenceofhighconcentrationofNH4+-N.TheloweredpHintheroot-soilinterfaceinducedbytheadditionoftheNH4-Npromotedthetransformationofphosphatesintheroot-soilinterface,enhancedthemobilizationandbioavailabilityofphosphates,andtherebyremarkablyincreasedtheabsorptionofphosphorusbyroots.

简介：对开发物理蒸汽免职(PVD)涂层为他们的优秀机械性质和腐蚀抵抗作为一组有希望的保护的涂层识别了的multilayered或nanolayered有许多兴趣。在这研究，multilayeredCrN/Cr2有不同bilayer时期的O3涂层()被弧离子plating(AIP)与纯氮和纯氧的其他的空气从一个Cr目标在擦亮的高速度钢底层上综合技术。结果表明multilayered涂层的微观结构，形态学和性质被bilayer时期强烈影响()。在multilayeredCrN/Cr2O3涂层：锋利的和模糊的。与减少价值，，宏粒子密度逐渐地减少了涂层microhardness，粘合剂力量并且穿首先稍微增加，然后减少或作为bilayer时期仍然保持稳定的抵抗<590nm。multilayeredCrN/Cr2有590nm的bilayer时期的O3涂层拥有了最好的全面性质，也就是最高的microhardness，最强壮的粘附，并且最低穿率。

简介：abstractclass和interface是Java语言中对于抽象类定义的两种机制,它们之间在对于抽象类定义的支持方面具有很大的相似性,有时可以相互替换,因此很多初学开发者在进行抽象类定义时对于abstractclass和interface的选择上比较模棱两可。实际上,两者之间还是有区别的,对于它们的选择可以反映出对于问题领域本质的理解、对于设计意图的理解是否正确、合理。本文将对它们之间的区别进行一番剖析,试图给读者提供一个在二者之间进行选择的依据。

简介：AbstractObjective:To analyze the temporal trends of maternal mortality ratio (MMR) due to obstetric hemorrhage and its specific causes in Chinese mainland from 2000 to 2019, to identify whether the rate of change has accelerated or slowed down during this period, and to find the prior cause of obstetric hemorrhage that needs to be intervened in the future.Methods:Individual information on maternal deaths and total number of live births from 336 surveillance sites across 31 provinces in Chinese mainland was collected from the National Maternal and Child Health Surveillance System between 2000 and 2019. Maternal death was defined according to the World Health Organization’s criterion. The final underlying cause of death was confirmed by the national review and was coded according to International Classification of Diseases -10. Linear trends for changes in characteristics of maternal deaths were assessed using linear or logistic models with the year treated as a continuous variable. The MMR and 95% confidence intervals (CI) for regions or causes were estimated by Poisson’s distribution. Joinpoint regression was used to assess the accurate temporal patterns.Results:The national MMR due to obstetric hemorrhage was 18.4 per 100,000 live births (95% CI: 15.0-22.2) in 2000. It peaked in 2001 (22.1 per 100,000 live births, 95% CI: 18.3-26.4) and was lowest in 2019 (1.6 per 100,000 live births, 95% CI: 1.0-2.3). For specific regions, the MMR due to obstetric hemorrhage in rural areas and western regions both experienced a slight rise, followed by a rapid decline, and then a slow decline. For specific causes, no change point was found in joinpoint analysis of the national MMR caused by placenta previa, postpartum uterine atony, and retained placenta (the annual percent change was -12.0%, -10.5%, and -21.0%, respectively). The MMR caused by postpartum hemorrhages (PPH) significantly declined by 8.0% (95% CI: 1.9-13.6) per year from 2000 to 2007. The annual percent change of MMR caused by PPH accelerated further to -25.0% between 2007 and 2011, and then decreased to -7.8% between 2011 and 2019. The proportion of maternal deaths due to antepartum hemorrhages increased from 7.6% (8/105) in 2000 to 14.3% (4/28) in 2019. The changes in the proportion of causes were different for maternal deaths due to PPH. The proportion of postpartum uterine atony increased from 39.0% (41/105) in 2000 to 60.7% (17/28) in 2019, and the proportion of uterine rupture also increased from 12.3% (13/105) in 2000 to 14.3% (4/28) in 2019. However, the proportion of retained placenta decreased from 37.1% (39/105) in 2000 to 7.1% (2/28) in 2019.Conclusion:Over the last 20 years, the intervention practice in China has proved that targeted interventions are beneficial in reducing the MMR due to obstetric hemorrhage. However, the MMR has reached a plateau and is likely to increase for some specific causes such as uterine rupture. China needs to develop more effective interventions to reduce maternal deaths due to obstetric hemorrhage, especially for postpartum uterine atony and uterine rupture.