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简介：Atypeofnovelinverterpowersupplysystemforhigh-powertwin-wirepulsedgasmetalarcwelding(GMAW)ispresentedmainlyfordealingwiththedisadvantagesoftheconventionalpowersupplyfortwin-wirepulsedGMAWofwhichtheoutputpowerisgenerallydifficulttoincreaseduetolimitationsofthepowerofsemiconductorsandthepowerdensityofmagneticdevices.Inthepowersuppliesforthemasterandslavearcs,thedigitalsignalprocessor(DSP)TMS320F28335isusedtoformtheDSP-basedsynergiccontrolsystemforparallelhigh-powerpulsedGMAW,whichachieveshigh-poweroutputoftwoparallelinverterscontrolledbyasingleDSP;master-slavecommunicationisachievedbyusingecontrollerareanetwork(eCAN)moduleofDSP,thusrealizinganti-phasepulseoutputofhigh-powertwin-wirepulsedGMAWandreducingtheinterferencebetweentwinarcs.Theexperimentresultsdemonstratethatthedesignedinverterpowersupplysystemforhigh-powertwin-wirepulsedGMAWcanbringabouthigh-powerefficiencyofwelding,stableweldingprocessandproperformationofwelds.

简介：低合金的钢(HSLA)使遭到了的一个高张力的热周期曲线的测量成双电线的沉没弧焊(锯)被介绍。热模拟测试被使用获得的曲线执行。影响坚韧在?50以不同方法。段和接口性质被测量。结果显示出穿着的板是的那20层比其它好。结合得好的穿着的板成功地在下列过程被获得：从18张层Al1060/Al3003表的基本的穿着的表第一在450点与44%的起始的滚动减小被获得???????????????″??吗？？

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简介：Withthickplatesof2219high-strengthalloy,themicrostructuresofweldedjointswithtwinwireMIGweldingwereanalyzed.Experimentalresultsshowthatnohotcrackwasfoundintheweldduetodiscontinuousdistributionofcocrystallizationwithlowmeltingtemperature,butporosityisseriousinthefirstweldseamthatismainlycomposedofequiaxialgrainswithunevensizes.Asthepoorpositionofthewholeweldedjoint,fusionzonehasbigandcoarsegrains,unevenmicrostructures;Inquenchingzone,thereexistalotofsoakedmicrostructuresthatcocrystallizationwithlowmeltingtemperaturesoluteintomatrix,thusstrengtheningthemetalinthiszone;Inexcessiveagingzone,muchmorephasesthatdistributeevenlywillbeseparatedfromthematrix;Outsidethiszone,propertiesandmicrostructuresofthemetalarebasicallysimilartomatrixduetotherelativelylowtemperatureorunaffectedheatinthezoneduringwelding.

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简介：Inthisstudy，theweldingthermalcyclecurveexhibitedtwotemperaturepeaksinhighheat-inputtwin-wireseparate-poolsubmerged-arcweldingandcoarse-grainedheataffectedzoneexistedintheweldedjoint.Theinclusionsofprimaryweldmetalandcoarse-grainedheataffectedzoneofCe-addedSAWshouldbeAl203,MnO,Si02,TiO,Ce2S3,CeS,Ce202SandCe203.Undertheeffectofweldingthermalcycle,oxy-sulfidesinclusionsofCe,thediameterofwhichwaslessthan2.0|Jim,slightlygrewlarger,butthecompositionandtypeoftheinclusionsdidn，tchange.ThemicrostructureofthelargeheatinputweldmetalhadacicularferritethatCeoxidesulphideparticlesinducednucleationandproeutectoidferrite.Inthecoarse-grainedheataffectedzoneofweldmetal,home-positionprecipitationofacicularferriteandsympatheticacicularferritewerebothobserved.Itwassupposedthatpreviouscrystalcellsofacicularferriteinaustenitegrainpromotedhome-positionprecipitationofacicularferrite.Meanwhile,sympatheticacicularferritetendedtonucleateattheprimaryacicularferritegrainboundaries,wherehighdislocationdensitywaslocated,andgrewinsidetheneighboringcarbon-depletedausteniticregions.Thegranularbainitenucleatedintheausteniticzonewithhighcarboncontentclosetoacicularferriteandsympatheticacicularferrite.

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简介：目的将评估可行性和由K电线和紧张乐队电线固定对待sternoclavicular关节脱臼的治疗学的效果，并且改进这种技术的安全和稳定性。这研究与平均数由9个盒子，6男性和3女性组成了的方法25年变老(范围，9-62年)。原因是在7种情况中的交通事故，掉在在1种情况中的1种情况和战斗里。到操作的从损害的持续时间是到7天的2个小时。有5左脱臼和4正确脱臼；8前面的脱臼和1以后的脱臼，包括一个与左olecranon骨折与左肩胛骨折和破裂结合了。用K电线和紧张乐队电线的开的减小和内部固定被执行对待脱臼。结果所有病人被跟随在上面为6～24个月，10个月平均。根据Rockwood手术后的sternoclavicular关节上的等级规模，8个盒子与13.88的一个平均分数完成了优秀结果，并且剩余的盒子与12的分数完成了好结果。解剖减小在所有情况中被获得。象严重感染没有如此的手术后的复杂并发症，对血容器和神经的损害，固定的失败，等等。病人们都对解剖减小和功能的恢复满意。K电线和紧张乐队电线固定的技术是保险箱的结论，简单，有效，不太侵略并且成功地在矫形外科被使用了。它在尽管它有一些劣势，对待sternoclavicular关节脱臼是有效的。

简介：AbstractThe pathophysiology of twin-to-twin transfusion syndrome (TTTS) is complex, and its understanding has evolved along with the evolution and revolution of fetal diagnostic and therapeutic techniques. Over the last few decades, several therapeutic interventions have been researched for improving the outcomes in TTTS. We present a summary of the current protocols for surveillance, diagnosis, and staging of TTTS in monochorionic pregnancies. We also describe in detail the technique for treatment of TTTS by endoscopic laser photocoagulation.

简介：MPower显然是疯了,虽然是第一次将触角伸向SUV领域,却制造了两个在W高达动画片里才会出现的怪物,身躯庞大的X5M和X6M。

简介：AbstractThe rate of twin pregnancies has increased over the last decades, largely because of the ongoing development of assisted reproductive technology and increased maternal age at childbearing. Twins have a higher risk of adverse outcomes during pregnancy and the perinatal period. The prevalence of umbilical cord abnormalities is higher for twin pregnancies compared with singleton pregnancies. Some of these abnormalities are nonspecific to twinning and can also be found in singleton gestations (such as velamentous cord insertion, vasa previa, and single umbilical artery). Other abnormalities are associated with monochorionic twins, such as umbilical cord entanglement, and umbilical proximate cord insertion. Most of these abnormalities can be detected by ultrasound evaluation. The early and accurate ultrasound diagnosis of chorionicity, amnionicity, and placental and umbilical cord characteristics is crucial if we are to predict the risk of complications and to determine the best management for twin pregnancies. Histopathological examination of the placenta and umbilical cord after delivery can help to confirm prenatal diagnosis and to provide a better understanding of the physiopathology of their abnormalities. The aim of this review was to emphasize the role that the umbilical cord plays in twin complications and to describe the management of these high-risk pregnancies.

简介：AbstractMode of delivery in twin gestation has been a matter of debate for decades. In 2013, the only randomized controlled trial concerning mode of delivery in twin gestations was published, answering some of the most pressing questions in this matter. The Twin Birth Study randomized patients carrying dichorionic-diamniotic or monochorionic-diamniotic twins, with the first twin in cephalic presentation, between 32 and 39 weeks of gestation, to planned vaginal vs. planned cesarean delivery, and found no significant differences in perinatal or maternal outcomes. These clinical findings greatly benefit our clinical practice, but there lacks related study investigating how the practices have changed. In this review, we searched PubMed from 1980 through January 2021 using combinations of the following terms: twin, delivery, vaginal delivery, and cesarean section. We will try to address the known literature before and after the publication of the Twin Birth Study in western countries and compare that to what has been practiced in China.

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简介：Thoughterroriststriggered(触发)thecollapse(倒塌)oftheWorldTradeCenter'sTwinTowers,muchoftheenergy--calculatedbyaphysicisttohavebeenatleast2percentthatoftheatomicbombdroppedonHiroshima(广岛)--wassuppliedbynature'smostubiquitous(普通存在的)force:gravity.

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简介：Thewavetransmissioncharacteristicsandwaveinducedpressuresontwinplatebreakwaterareinvestigatedexperimentallyinregularandrandomwaves.Atotaloftwentypressuretransducersarefixedonfoursurfacesoftwinplatetomeasurethewaveinduceddynamicpressures.Thespatialdistributionofdynamicwavepressureisgivenalongthesurfaceofthetwinplate.Theupliftwaveforceobtainedbyintegratingthehydrodynamicpressurealongthestructureispresented.DiscussedaretheinfluenceofdifferentincidentwaveparametersincludingtherelativeplatewidthB/L,relativewaveheight/iHaandrelativesubmergencedepths/aonthenon-dimensionaldynamicwavepressuresandtotalwaveforces.Fromtheinvestigation,itisfoundthattheoptimumtransmissioncoefficient,tKoccursaroundB/L0.41~0.43,andthetwinplatebreakwaterismoreeffectiveindifferentwaterdepths.Themaximumofpressureratiodecreasesfrom1.8to1.1whentherelativesubmergencedepthoftopplateisincreasedfrom0.8to+0.8.

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