简介：AbstractPosterior placenta accreta spectrum (PAS) disorders are infrequent but potentially associated with significant maternal mortality and morbidity, especially if not diagnosed prenatally. Analysis of published literature is problematic since most experiences included only a few cases. Knowledge of the risk factors associated with posterior PAS is crucial to identifying mothers at higher risk and ask for high sensitivity studies. Ultrasound has poor diagnostic accuracy in detecting posterior PAS, while magnetic resonance imaging better delineates the posterior uterine wall. In comparison, prenatal imaging’s diagnostic performance in detecting posterior PAS is significantly lower than anterior placenta invasion. Management of posterior PAS depends on several factors, including maternal hemodynamic status, available resources, clinical presentation, and invasion severity. For accreta or increta cases, a compression suture is habitually enough to perform hemostasis. Nevertheless, organ involvement habitually requires a multidisciplinary team with the assistant of a general or coloproctology surgeon. The present article aims to update the risk factors, prenatal diagnosis, and surgical management of pregnancies complicated by posterior PAS.

简介：现在的调查被执行决定通过最佳索引因素(OIF)选择的特征是否能作为与一起考虑的所有特征相比象二不同的年的叠的图象一样在单个年的卫星图象上提供各种各样的范畴的改进分类精确性。进一步，以便决定是否在那里发生有特征的OIF价值的相应增加的不同范畴的分类精确性的增加从两个提取了单个年并且叠了图象，我们与特征的不同联合的OIF价值执行了在各种各样的范畴的制片人精确性(PA)之间的线性回归。调查证明那在那里发生在二不可渗透的范畴viz的PA的重要改进。中等布满建筑物、低密度布满建筑物从作为与所有乐队相比与最高的OIF值联系的乐队和主要部件和为两个的主要部件的分类坚定单个年和叠的图象分别地。回归分析为决定单个年并且叠了分别地意味着与OIF价值的相应增加的在信息内容的增加之间的直接关系的流行的图象的各种各样的范畴展出了在回归系数和OIF价值之间的积极趋势。研究证明特征提取了通过从单个年和叠的图象的OIF能够作为与一起分享的所有特征相比提供显著地改进的PA。

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.

简介：口语教学是语言教学中不可或缺的重要部分，但甘肃省高考却没有开设对英语口语表达进行测试的科目。为了能够弥补这个“教学漏洞”，使英语教学更好地作用于学生的交流过程，体现出语言教学的本质，我们应该逐步实施从Accuracy（准确性）到Fluency（流利性）的学生英语口语训练活动。

简介：Usingtherecentlydevelopedfinite-basis-setmethodwithBsplines,excitedstatesofHatomsinamagneticfieldhavebeencalculated.Energylevelsarepresentedforthetenexcitedstates,2s_0,3d′_0,3p_0,3d_(-1),3d_(-1),4d_(-1),3d_(-2),4d_(-2),4f_(-2),and5f_(-2)asafunctionofmagneticfieldstrengthswitharangefromzeroupto2.35×10~6T.Theobtainedresultsarecomparedwithavailablehighaccuracytheoreticaldatareportedintheliteratureandfoundtobeinexcellentagreement.Thecomparisonalsoshowsthatthecurrentmethodcanproduceenergylevelswithanaccuracyhigherthantheexistinghighaccuracymethod[Phys.Rev.A54(1996)287].Herehighaccuracyenergylevelsareforthefirsttimereportedforthe3d′_0,4d_(-1),4d_(-2),4f_(-2),and5f_(-2)states.

简介：Conventionalcameracalibrationthatemployscalibrationtargetsisacommonlyusedmethodtoacquireacamera'sintrinsicand/orextrinsicparameters.Thecalibrationtargetsareusuallydesignedasperiodicarraysofsimplehigh-contrastpatternsthatprovidehighlyaccurateworldcoordinatesystempointsandthecorrespondingimagepixelcoordinatesystempoints.Theexistingpixelcoordinateextractionalgorithmscanreachasub-pixellevel;however,theytreateachsinglepatterninoneimageasanindependentindividual,whichmakesitdifficulttofurtherimproveextractionaccuracy.Inthispaper,anovelmethodisproposedbyutilizingtheperiodicarrangementcharacteristicsofthecalibrationtargetpatternasaglobalconstrainttoimprovethecalibrationaccuracy.Basedonacamera'spinholemodel,theintersectionpointoftwofittedcurvesisusedasanoptimizedpixelpointtoreplacetheinitialone.Followingthepixelcoordinateoptimizationprocedures,experimentswereperformedusingrealdatafroma3Dlaserlinescannerandadynamicprecisioncalibrationtarget.Ourresultsshowthattherelativeerrorsofcamerahomographymatrixelementsobtainedbytheproposedoptimizationmethodwerereducedcomparedwiththecommonlyusedmethod.Theaveragecoordinatemeasurementaccuracycanbeimprovedbynearly0.05mm.Itisshownthattheproposedoptimizationmethodcanenhancethecameracalibrationaccuracy,especiallywhentheextractedpixelsareofpoorerprecision.

简介：Accurateestimationofstiffnesslossisachallengingprobleminstructuralhealthmonitoring.Inthisstudyorthogonalwaveletdecompositionisusedforidentifyingthestiffnesslossinasingledegreeoffreedomspring-mass-dampersystem.Theeffectsofexcitationfrequencyonaccuracyofdamagedetectionisinvestigated.Resultsshowthatpseudo-aliaseffectscausedbytheorthogonalwaveletdecomposition(OWD),affectdamagedetectability.Itisdemonstratedthattheproposedapproachissuitablefordamagedetectionwhentheexcitationfrequencyisrelativelylow.Thisstudyshowshowaprioriknowledgeaboutthesignalandabilitytocontrolthesamplingfrequencycanenhancedamagedetectability.

简介：为系统建模的Cloud-Aerosol-Radiation(汽车)整体最近被造了更好理解云/喷雾器/放射过程并且决定云/喷雾器/放射的不同处理在气候模型引起的无常。汽车系统包括云，喷雾器，和在文学可得到的放射进程的一个大计划集合，包括通常由带GCM的世界使用的那些。在这研究，详细说明了全面精确性的分析，CAR系统的效率被执行。尽管有使用的不同观察，CAR整体工具的全面精确性被发现对短波(SW)和longwave(LW)很好放射计算。与ISCCP(国际卫星云气候学工程)相比为2004年7月拿百分比错误数据在上(60tent和分析o吗？？

简介：在放的精确的点(PPP)，一些不可能的精确地模仿的系统的错误不可避免地在GPS观察和愿望尚待降级天顶tropospheric延期(ZTD)的精确评价。在GPSPPP模式使用的随机的模型被比较。在这篇论文，研究结果证明导出PPP的ZTD的精确能显然通过为GPS大小选择一个合适的随机的模型被改进。低举起的观察能论及能改进ZTD的评价的更多的对流层信息。一个新随机的模型基于卫星，低举起余弦平方被介绍。结果表演用卫星的随机的模型基于举起的余弦平方功能比以前的随机的模型好。

简介：Inthispaper,analmostP-stabletwo-stepsixth-orderHybridmethodwithphase-lagoforderinfinityandaclassexpliciteighth-orderObreckoffmethodswithphase-lagoforder10-24aredevelopedforthenumericalintegrationofthespecialsecond-orderperiodicinitial-valueproblems.Thesemethodshavetheadvantageofhigheralgebraicorderandconsiderablysmallerphase-tagcomparedwithsomemethodsin[1-6].Numericalexamplesindicatethatthesenewmethodsaremoreaccuratethanmethodsdevelopedby[1-6].

简介：Asingle-particlemicrobeamfacilityhasbeenconstructedattheLaboratoryofIonBeamBioengineering(LIBB),ChineseAcademyofSciences.Thesystemisdesignedtodeliverthedefinednumberofhydrogenions,coveringarangeofenergyfrom1.0to3.5MeV,intoanareasmallerthanthenucleiofindividuallivingcells.AccuracyoftheparticledetectionsystemandthecelltargetingsysteminthefacilityhasbeenassessedusingCR39(nucleartrackdetector)for2.3MeVprotons.Theresultsdemonstratethattheparticledetectionefficiencyisabove98%,andtheoveralltargetingaccuracyofthemicrobeamislimitedwithin3μmformorethan90%hits.

简介：Anopticallengthmeasuringsystembaseonall-fiberopticinterferometerisproposed.Thetheoreticalanalysisindicatesthat,whenthetwobranchesoftheinterferometerareequal,theoutputhavethemaximumcoherentintensity.Therefore,theopticallengthcanbeobtainedbymeasuringthedistanceofcollimatormovement.Throughtheexperimentandsimulation,theimpactofthesignal-to-noiseratioandfluctuationofthecouplingefficiencyonnullerrorhasbeenobtained.

简介：Theclassificationaccuracyofthevariouscategoriesontheclassifiedremotelysensedimagesareusuallyevaluatedbytwodifferentmeasuresofaccuracy,namely,producer'saccuracy(PA)anduser'saccuracy(UA).ThePAofacategoryindicatestowhatextentthereferencepixelsofthecategoryarecorrectlyclassified,whereastheUAofacategoryrepresentstowhatextenttheothercategoriesarelessmisclassifiedintothecategoryinquestion.Therefore,theUAofthevariouscategoriesdeterminesthereliabilityoftheirinterpretationontheclassifiedimageandismoreimportanttotheanalystthanthePA.ThepresentinvestigationhasbeenperformedinordertodetermineifthereoccursimprovementintheUAofthevariouscategoriesontheclassifiedimageoftheprincipalcomponentsoftheoriginalbandsandontheclassifiedimageofthestackedimageoftwodifferentyears.WeperformedtheanalysesusingtheIRSLISSIIIimagesoftwodifferentyears,i.e.,1996and2009,thatrepresentthedifferentmagnitudeofurbanizationandthestackedimageofthesetwoyearspertainingtoRanchiarea,Jharkhand,India,withaviewtoassessingtheimpactsofurbanizationontheUAofthedifferentcategories.TheresultsoftheinvestigationdemonstratedthatthereoccurssignificantimprovementintheUAoftheimperviouscategoriesintheclassifiedimageofthestackedimage,whichisattributabletotheaggregationofthespectralinformationfromtwicethenumberofbandsfromtwodifferentyears.Ontheotherhand,theclassifiedimageoftheprincipalcomponentsdidnotshowanyimprovementintheUAascomparedtotheoriginalimages.

简介：Thispaperdiscussesthetime-of-arrival(TOA)basedindoorvisiblelightcommunication(VLC)positioningsysteminanon-line-of-sightenvironment.Thepropagationdelayisassumedtobegammadistributed.ThegeneralizedCramer–Raolowerboundformultipathpropagationisderivedasthetheoreticalaccuracylimitation.Theperformanceofthepositioningsystemisaffectedbytheshapeparameterandthescaleparameterofgammadistribution.Theinfluencesonpositioningaccuracyofmultipatheffectsareanalyzedthroughdiscussingthephysicalmeaningofthegammadistributionparameters.Itisconcludedthatthelowerboundofpositioningaccuracyisattainedwhenvarianceofthenon-line-of-sightpropagation-inducedpathlengthsiszero.Thesimulationresultprovesthatthetheoreticalpositioningaccuracyisintheorderofcentimeterswiththegivenscenario.

简介：Ritzmethodisaneffectivewaywidelyusedtoanalyzethetransversebendingofthinrectangularplates.Itsaccuracydependscompletelyonthebasisfunctionsselected.Thispaperselectsthesuperpositionofsineserieswithpolynomialsasthebasisfunctionsofthinrectangularplates.Thecalculatingformulaearenotonlysimpleandeasilyprogrammed,butalsohavehighaccuracy.Finally,twonumericalresultsaregivenandcomparedwiththoseobtainedbytheclassicalmethod.

简介：AbstractBackground:Rebleeding can cause a catastrophic outcome after aneurysmal subarachnoid hemorrhage. A clinical + morphology nomogram was promoted in our previous study to assist in discriminating the rupture intracranial aneurysms (RIAs) with a high risk of rebleeding. The aim of this study was to validate the predictive accuracy of this nomogram model.Method:The patients with RIAs in two medical centers from December 2020 to September 2021 were retrospectively reviewed, whose clinical and morphological parameters were collected. The Cox regression model was employed to identify the risk factors related to rebleeding after their admission. The predicting accuracy of clinical + morphological nomogram, ELAPSS score and PHASES score was compared based on the area under the curves (AUCs).Results:One hundred thirty-eight patients with RIAs were finally included in this study, 20 of whom suffering from rebleeding after admission. Hypertension (hazard ratio (HR), 2.54; a confidence interval of 95% (CI), 1.01-6.40; P = 0.047), bifurcation (HR, 3.88; 95% CI, 1.29-11.66; P = 0.016), and AR (HR, 2.68; 95% CI, 1.63-4.41; P < 0.001) were demonstrated through Cox regression analysis as the independent risk factors for rebleeding after admission. The clinical + morphological nomogram had the highest predicting accuracy (AUC, 0.939, P < 0.01), followed by the bifurcation (AUC, 0.735, P = 0.001), AR (AUC, 0.666, P = 0.018), and ELAPSS score (AUC, 0.682, P = 0.009). Hypertension (AUC, 0.693, P = 0.080) or PHASES score (AUC, 0.577, P = 0.244) could not be used to predict the risk of rebleeding after admission. The calibration curve for the probability of rebleeding showed a good agreement between the prediction through clinical + morphological nomogram and actual observation.Conclusion:Hypertension, bifurcation site, and AR were independent risk factors related to the rebleeding of RIAs after admission. The clinical + morphological nomogram could help doctors to identify the high-risk RIAs with a high predictive accuracy.

简介：Anewscreen-spotimagingmethodbasedonopticalmeasurementisproposed,whichisapplicabletotheclose-rangemeasurementofaircraft'sthree-dimensional(3D)attitudeparameters.Lasertrackerisusedtofinishtheglobalcalibrationsofthehigh-speedcamerasandthefixedscreensontestsite,aswellastoestablishmedia-coordinate-framesamongvariouscoordinatesystems.Thelasercooperationobjectmountedontheaircraftsurfaceprojectslaserbeamsonthescreensandthehigh-speedcamerassyn-chronouslyrecordthelight-spots'positionchangingwithaircraftattitude.Therecordedimagesequencesareusedtocomputetheaircraftattitudeparameters.Basedonthematrixanalysis,theerrorsourcesofthemeasurementaccuracyareanalyzed,andthemaximumrelativeerrorofthismathematicalmodelisestimated.Theexperimentalresultshowsthatthismethodeffectivelymakesthechangeofaircraftpositiondistinguishable,andtheerrorofthismethodisnomorethan3′whiletherotationanglesofthreeaxesarewithinacertainrange.

简介：

简介：在恢复地球严肃模特儿(EGM)由创造的标准方程的特征最少平方(LS)从在原处扰乱的潜力的调整详细被讨论。标准方程仅仅看情况，这能被结束先验的重力模型的在轨道，和选择没在LS答案上有效果。因此，恢复严肃模型的精确性能精确地被模仿。从这个点开始，与噪音的不同水平沿着轨道扰乱潜力的四个集合被模仿并且被用来恢复EGM。结果证明在加速表刻度的当前的精确性水平上，EGM的精确性不是足够的反映地球的重力场的时间可变性，作为揭示的动态方法。

简介：