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  • 简介:Thispaperstudiestheinteractionofshockandgradientwave(soundwave)ofsolutionstothesystemofinviscidisentropicgasdynamicsasamodelforthecorrespondingproblemsfornonlinearhyperbolicsystems.Theproblemcanbereducedtoaboundaryvalueprobleminawedgeddormain,ByusingthemethodofconstructingasymptoticsolutionsandNewton'siterationprocessitisprovedthatifaweakshockhitsagradientwave,thenthegrandientwavewillsplitintotwogradientwaves,whiletheshockcontinusespropagating.Inthispapertheauthorreducestheproblemtoastandardformandconstructsasymptoticsolutionoftheproblem.Theexistenceofthegenuinesolutionwillhegiveninthefollowingpaper.

  • 标签: 震动交感 声波 气体动力学 数学模型
  • 简介:正常冲击波,在一个机翼上终止一个本地超声的区域,限制它的表演并且成为来源高加速冲动的噪音。使用被动控制瓦解被建议冲击波。这个方法获得的流动结构的细节数字地被学习。一个新边界条件被开发了,它的应用程序的结果在嘴流动对实验被验证。崩溃被证实了并且详细说明流动细节的分析的冲击波的方法被介绍。由渐渐的压缩的一个冲击波的替换完全改变高速度的来源它的减小的冲动的噪音和熊潜力。关键词接近音速的流动-冲击波边界层相互作用-被动控制CLC数字O357.4+2

  • 标签: 跨音速流 振波边界层交互作用 被动控制 机翼
  • 简介:Inordertoovercometheexistingdisadvantagesofofflinelasershockpeeningdetectionmethods,anonlinedetectionmethodbasedonacousticwavesignalsenergyisprovided.Duringthelasershockpeening,anacousticemissionsen-soratadefinedpositionisusedtocollecttheacousticwavesignalsthatpropagateintheair.Theacousticwavesignalissampled,stored,digitallyfilteredandanalyzedbytheonlinelasershockpeeningdetectionsystem.Thenthesystemgetstheacousticwavesignalenergytomeasurethequalityofthelasershockpeeningbyestablishingthecorrespondencebetweentheacousticwavesignalenergyandthelaserpulseenergy.ThesurfaceresidualstressesofthesamplesaremeasuredbyX-raystressanalysisinstrumenttoverifythereliability.Theresultsshowthatboththesurfaceresidualstressandacousticwavesignalenergyareincreasedwiththelaserpulseenergy,andtheirgrowthtrendsareconsistent.Finally,theempiricalformulabetweenthesurfaceresidualstressandtheacousticwavesignalenergyisestablishedbythecubicequationfitting,whichwillprovideatheoreticalbasisforthereal-timeonlinedetectionoflasershockpeening.

  • 标签: LASER shock PEENING ACOUSTIC WAVE LASER
  • 简介:摘要BACKGROUND AND OBJECTIVESpasticity is a common sequala of the upper motor neuron lesions. For instance, it often occurs in the first 4 weeks after stroke and is seen in more than one-third of stroke survivors after 12 months. In recent years, extracorporeal shock wave therapy (ESWT) has been recognized as a safe and effective method for reducing muscle spasticity. Possible/relevant mechanisms include nitric oxide production, motor neuron excitability reduction, induction of neuromuscular transmission dysfunction, and direct effects on rheological properties. There are two types of ESWT, focused and radial, with the radial type more commonly applied for treating muscle spasticity. Concerning the optimal location for applying ESWT, the belly muscles and myotendinous junction seem to produce comparable results. The effects of ESWT on spasticity are known to last at least four to six weeks, while some studies report durations of up to 12 weeks. In this review, the authors will focus on the current evidence regarding the effectiveness of ESWT in spasticity, as well as certain technical parameters of ESWT, e.g., the intensity, frequency, location, and number of sessions. The pertinent literature has been reviewed, with an emphasis on post-stroke upper limbs, post-stroke lower limbs, cerebral palsy, and multiple sclerosis. In short, while ESWT has positive effects on parameters such as the modified Ashworth scale, mixed results have been reported regarding functional recovery. Of note, as botulinum toxin injection is one of the most popular and effective pharmacological methods for treating spasticity, studies comparing the effects of ESWT and botulinum toxin injections, and studies reporting the results of their combination, are also reviewed in this paper.

  • 标签: eion review
  • 简介:Aninvestigationofthepassivecontrolofshockwave/boundarylayerinteractionforreducingtheamplitudeoftheshockoscillationwasconductedonthecirculararc-wedge(CW)profilecascadeina220^290mmtransoniccompressorcascadewindtunnel.Aperforatedsurfacewithacavitybeneathitwaspositionedonthesuctionsurfaceofthebladeatthelocationofshockimpingement.TheSchlierenandhigh-speedphotographsforflowoverpervoratedbladearepresentedandcomparedwiththeresultsforsolidblades,Withtheperforatedsurface,thehigh-speenphotographsindicatedansignificantsuppressionofshockosciation.

  • 标签: 压缩机 冲击波 边界层 互作用
  • 简介:这研究的目的是在一条微隧道为控制使用冲击波。冲击波被在隧道搏动的激光横梁集中的激光产生。使用脉搏激光产生一个冲击波,非静止的流动在在平行盘子之间的小空间被导致。球形、圆柱的吃惊繁殖与schlieren方法被观察。吃惊马赫数字与时间减少并且来临到统一。是在以前的调查报导了,吃惊速度在一个短远处和时间被稀释。在现在的实验,它没处于在球形、圆柱的吃惊实验之间的吃惊速度被发现显著差别。随后,圆柱的冲击波导致的流动用PIV技术被学习。烟tracer在实验被使用,它的速度在100渭s以内被测量。数字模拟被执行调查在气体和烟粒子之间的动量松驰。一个合适的吃惊开始模型在模拟被介绍。试验性的结果证明一个宽加速和减速地区在冲击波后面存在。另外,在试验性的数据的松驰距离在数字模拟比那长得多。关键词微强风的波浪-激光集中-流动可视化-PIVCLC数字O354

  • 标签: 微爆波 激光聚焦 PIV 流体可视化 纳米技术 流动控制
  • 简介:Atheoreticalmodelisproposedtodescribethemechanismoflaser-inducedplasmashockwaveevolutioninair.Toverifythevalidityofthetheoreticalmodel,anopticalbeamdeflectiontechniqueisemployedtotracktheplasmashockwaveevolutionprocess.Thetheoreticalmodelandtheexperimentalsignalsarefoundtobeingoodagreementwitheachother.Itisshownthatthelaser-inducedplasmashockwaveundergoesformation,increaseanddecayprocesses;theincreaseandthedecayprocessesofthelaser-inducedplasmashockwaveresultfromtheoverlappingofthecompressionwaveandtherarefactionwave,respectively.Inaddition,thelaser-inducedplasmashockwavespeedandpressuredistributions,bothafunctionofdistance,arepresented.

  • 标签: 激光诱导等离子体 等离子体冲击波 演变 空气 机制 衰变过程
  • 简介:强壮的、正常冲击波,在一个机翼,不是仅仅限制上终止一个本地超声的区域空气动力学的性能而且成为高速度的冲动的直升飞机噪音的来源。转子片上的一个被动控制系统(一个穿孔盘子盖住的一个洞)的应用程序应该减少动人的震动创造的噪音。这篇文章盖住Bohning/Doerffer蒸发法律的数字实现进SPARC代码并且为接近音速的嘴的相对简单的几何学对试验性的数据包括扩大确认。它是向与减少被动控制设备在的噪音装备的一个直升飞机转子的完整的模拟的第一个步骤徘回并且处于前面的飞行条件。

  • 标签: 多孔板 被动控制 冲击波强度 边界层 激波 超声波
  • 简介:在现在的学习,一个计算液体动力学工作被执行在超声的潮湿的空气喷气由冷凝作用调查冲击波的出现。不稳定的、可压缩的axisymmetric海军司烧方程被TVD(减少的全部的变化)解决在这研究的计划。数字模拟为低压力比率和各种各样的湿度被执行了。结果为低压力比率在超声的潮湿的空气喷气看冲击波的出现马赫磁盘什么时候不发生,取决于空气的湿度。

  • 标签: 空气喷射 超音速 冲击波 潮湿 STOKES方程 计算流体动力学
  • 简介:这份报纸论述大气的空气的数字分析通过deLaval嘴的接近音速的流动。从本质上讲,大气的空气总是包含水蒸汽的某个数量。计算与高扩大率用一张Laval嘴被做并且一会聚分叉(CD)一半嘴,是指了一接近音速更弥漫,与慢得多的扩大率。计算用内部CFD代码被执行。计算模型使由于在潮湿的空中包含的水蒸汽的自发的冷凝作用模仿液体阶段的形成可能。接近音速的流动计算也在嘴考虑一个正常冲击波的存在分析液体阶段蒸发的效果的超声的部分。

  • 标签: 潮湿的空气 冷凝作用 接近音速的流动 冲击波 CFD 模拟 内部代码
  • 简介:AbstractPurpose:Blast lung injury (BLI) is the most common damage resulted from explosion-derived shock wave in military, terrorism and industrial accidents. However, the molecular mechanisms underlying BLI induced by shock wave are still unclear.Methods:In this study, a goat BLI model was established by a fuel air explosive power. The key genes involved in were identified. The goats of the experimental group were fixed on the edge of the explosion cloud, while the goats of the control group were 3 km far away from the explosive environment. After successful modeling for 24 h, all the goats were sacrificed and the lung tissue was harvested for histopathological observation and RNA sequencing. Gene ontology (GO) and kyoto encyclopedia of genes and genomes (KEGG) analysis were performed to identify the main enriched biological functions of differentially expressed genes (DEGs). Quantitative real-time polymerase chain reaction (qRT-PCR) was used to verify the consistency of gene expression.Results:Of the sampled goat lungs, 895 genes were identified to be significantly differentially expressed, and they were involved in 52 significantly enriched GO categories. KEGG analysis revealed that DEGs were highly enriched in 26 pathways, such as cytokine-cytokine receptor interaction, antifolate resistance, arachidonic acid metabolism, amoebiasis and bile secretion, JAK-STAT, and IL-17 signaling pathway. Furthermore, 15 key DEGs involved in the biological processes of BLI were confirmed by qRT-PCR, and the results were consistent with RNA sequencing.Conclusion:Gene expression profiling provide a better understanding of the molecular mechanisms of BLI, which will help to set strategy for treating lung injury and preventing secondary lung injury induced by shock wave.

  • 标签: Blast lung injury Shock wave Differentially expressed genes RNA sequencing Transcriptome
  • 简介:Inthepresentpaper,theefficiencyofanenhancedformulationofthestabilizedcorrectivesmoothedparticlemethod(CSPM)forsimulationofshockwavepropagationandreflectionfromfixedandmovingsolidboundariesincompressiblefluidsisinvestigated.TheLagrangiannatureanditsaccuracyforimposingtheboundaryconditionsarethetwomainreasonsforadoptionofCSPM.Thegoverningequationsarefurthermodifiedforimpositionofmovingsolidboundaryconditions.Inadditiontothetraditionalartificialviscosity,whichcanremovenumericallyinducedabnormaljumpsinthefleldvalues,avelocityfieldsmoothingtechniqueisintroducedasanefficientmethodforstabilizingthesolution.Themethodhasbeenimplementedforone-andtwo-dimensionalshockwavepropagationandreflectionfromfixedandmovingboundariesandtheresultshavebeencomparedwithotheravailablesolutions.Themethodhasalsobeenadoptedforsimulationofshockwavepropagationandreflectionfrominfiniteandfinitesolidboundaries.

  • 标签: 光滑粒子法 边界条件 稳定解 移动 波反射 冲击波传播
  • 简介:在这份报纸,为在管的超声的内部流动的调查的马赫4超声的风隧道的轮廓第一被描述。第二,2和马赫4伪吃惊在方形的管挥动的马赫的地点,结构和特征被颜色schlieren相片和管墙压力调查变化大小。最后,墙砍有马赫4伪吃惊的方形的管的墙挥动的方面,顶和底部上的压力分布是由shear的调查品质上压力敏感的液体水晶可视化方法。在第一震动下面的方面墙边界层分离区域在最高的墙附近是狭窄的,当在第一震动下面的方面墙边界层分离区域在底部墙附近是很宽的时。关键词超声的内部流动-伪吃惊波浪-流动可视化-砍压力敏感的液体水晶CLC数字O357.4+2

  • 标签: 超声内流 假振波 剪切应力敏感液晶 管壁压力涨落测量
  • 简介:Whennon-equilibriumcondensationoccursinasupersonicflowfield.theflowisaffectedbythelatentheatreleased.Inthepresentstudy.inordertocontrolthetransonicflowfieldwithshockwave,acondensingflowwasproducedbyanexpansionofmoistaironacircularbumpmodelandshockwaveswereoccurredinthesupersonicpartsofthefields.Furthermore,theadditionalpassivetechniqueofshock/boundarylayerinteractionusingtheporouswallwithacavityunderneathwasadoptedinthisflow.Theeffectsofthesemethodsontheshockwavecharacteristicswereinvestigatednumericallyandexperimentally.Theresultobtainedshowedthatthetotalpressurelossintheflowfieldsmightbeeffectivelyreducedbythesuitablecombinationbetweennon-equilibriumcondensationandthepositionofporouswall.

  • 标签: 跨音速流动 非平衡压缩 边界层 流动控制 多孔渗水 冲击波
  • 简介:Thepropagationofshockwavesinacellularbarissystematicallystudiedintheframeworkofcontinuumsolidsbyadoptingtwoidealizedmaterialmodels,viz.thedynamicrigid,perfectlyplastic,locking(D-R-PP-L)modelandthedynamicrigid,linearhardeningplastic,locking(D-R-LHP-L)model,bothconsideringtheeffectsofstrain-rateonthematerialproperties.Theshockwavespeedrelevanttothesetwomodelsisderived.ConsiderthecaseofabarmadeofoneofsuchmaterialwithinitiallengthL0andinitialvelocityviimpingingontoarigidtarget.Thevariationsofthestress,strain,particlevelocity,specificinternalenergyacrosstheshockwaveandtheceasedistanceofshockwavearealldeterminedanalytically.Inparticularthe'energyconservationcondition'andthe'kinematicexistencecondition'asproposedbyTanetal.(2005)isre-examined,showingthatthe'energyconservationcondition'andtheconsequent'criticalvelocity',i.e.theshockcanonlybegeneratedandsustainedinR-PP-Lbarswhentheimpactvelocityisabovethiscriticalvelocity,isincorrect.Instead,withelasticdeformation,strain-hardeningandstrain-ratesensitivityofthecellularmaterialsbeingconsidered,itisappropriatetoredefineafirstandasecondcriticalimpactvelocityfortheexistenceandpropagationofshockwavesincellularsolids.StartingfromthebasicrelationsforshockwavepropagatinginD-R-LHP-Lcellularmaterials,anewmethodforinverselydeterminingthedynamicstress-straincurveforcellularmaterialsisproposed.Byusinge.g.acombinationofTaylorbarandHopkinsonpressurebarimpactexperimentaltechnique,thedynamicstress-straincurveofaluminumfoamcouldbedetermined.Finally,itisdemonstratedthatthisnewformulationofshocktheoryinthisone-dimensionalstressstatecanbegeneralizedtoshocksinaone-dimensionalstrainstate,i.e.forthecaseofplateimpactoncellularmaterials,bysimplymakingproperreplacementsoftheelasticandplasticconstant

  • 标签: 临界速度 波的传播 酒吧 节能 HOPKINSON压杆 应变率敏感性
  • 简介:摘要ObjectiveTo evaluate the effectiveness of radial extracorporeal shock wave therapy on ankle flexor spasticity in stroke survivors and to reveal changes in the fibroelastic components of muscle.DesignRandomized controlled trial.SettingInpatient neuro-rehabilitation clinic of a university hospital.ParticipantsStroke patients with ankle flexor spasticity.InterventionsPatients were randomized to three groups; radial extracorporeal shock wave therapy, sham, or control. Active and sham therapy were administered two sessions/week for two weeks. All patients received conventional rehabilitation.Main measuresThe primary outcome was Modified Ashworth Scale. Secondary outcomes were the Tardieu Scale and elastic properties of plantar flexor muscles assessed by elastography (strain index). All assessments were performed before, immediately after the treatment, and four weeks later at follow-up.ResultsFifty-one participants were enrolled (active therapy n=17, sham n=17, control n=17). Modified Ashworth scores showed a significant decrease in the active therapy group (from 2.47±0.72 to 1.41±0.62) compared to sham (from 2.19±1.05 to 2.06±1.12) and control (from 2.06±0.85 to 2.00±0.73) groups immediately after the treatment (P<0.001). Tardieu results were also in concordance (P<0.001), however this effect was not preserved at follow-up. Elastic properties of the ankle flexors were improved in all groups at both assessments after the therapy showing significant decreases in strain index (P<0.001). However, there was no difference among the groups in terms of improvement in elastography.ConclusionRadial extracorporeal shock wave therapy has short-term anti-spastic effects on ankle flexor muscles when used as an adjunct to conventional rehabilitation.

  • 标签: ESWT Stroke ankle elastography spasticity
  • 简介:在墙附近的制作反强风墙和分发法律上的大量冲击波效果被在表面爆炸测试方法附近使用调查并且女性。反强风墙的前部和背后上的压力时间历史和变化法律在不同爆炸距离和炸毁的变化的测试,以及在在测试和数字计算之间的比较被采用。当爆炸距离超过2m时,反强风墙上的大量冲击波效果与计算实质上一致的测试结果表演在表面爆炸下面用标准结果,在墙后面的过压的分发基于small-large-small根据变化法律被获得。在墙后面的山峰过压通常由1.52.5multiples,和在墙后面的保护的造的山峰过压出现在墙高度,这也被表明能被使用制作反强风墙有效地减少。

  • 标签: 抗爆炸墙 近表面爆炸 超压力 冲击波