学科分类
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176 个结果
  • 简介:在在机翼附近的接近音速的流动的不稳定的现象在扇子,压缩机片和蝴蝶阀门的流动地里被观察,并且这经常引起象aeroacoustic噪音那样的严重问题,颤动。在蒸汽在主要流动被包含的接近音速或超声的流动,流动的快速的扩大可以产生一个非平衡冷凝作用。然而,在机翼附近的接近音速的内部流动上的非平衡冷凝作用的效果还没令人满意地被澄清了。在现在的学习,圆形的弧片上的自我刺激的冲击波摆动上的潮湿的空气的非平衡冷凝作用的效果数字地被调查。结果证明在有非平衡冷凝作用的情况中,没有非平衡冷凝作用,流动摆动的频率变得比那些小。

  • 标签: 潮湿空气 非平衡凝结 圆弧型叶片 激波 非定常行为 跨音速流
  • 简介:微弧的氧化(毛)/zinc硬脂酸盐(ZnSA)合成涂层经由毛与superhydrophobicZnSA的电极淀积处理并且随后的封上被制作。表面形态学,化学作文和涂层的腐蚀抵抗用扫描电子显微镜学的地排放被调查,Fourier变换红外线,X光检查衍射并且电气化学并且氢进化大小。结果显示毛涂层被下列superhydrophobicZnSA涂层高效地封上。MAO/ZnSA合成涂层显著地由于它的superhydrophobic功能提高了Mg合金Mg-4Li-1Ca的腐蚀抵抗。另外,腐蚀机制为合成涂层被建议并且讨论。

  • 标签: 镁合金 微弧的氧化 Superhydrophobic 涂层 腐蚀
  • 简介:目的分析鼻咽癌放射治疗IMRT与RapidArc凋强放疗计划方案,为临床提供参考。方法10例鼻咽癌CT增强扫描模拟定位后勾画CTV,按统一标准外扩PTV;实施均分9野IMRT计划和单弧、双弧、3弧Arc调强计划;以门V处方剂量70Gy,分析各治疗计划靶区剂量分布和危及器官受限剂量,进行剂量学对比研究并比较治疗时间的长短。结果IMRT调强计划适彤指数及不均匀指数明显优于单弧,与双弧和3弧没有明显区别;各计划之间危及器官受量均低于参考受限剂量;照射体积(irradiationvolume,IV)未见明显区别;机器跳数(monitorunit,MU),Arc调强计划明显低丁IMRT调强计划;治疗时问上Arc凋强计划更短。结论目前虽IMRT计划更符合鼻咽癌的治疗剂量要求,但Arc计划在缩短治疗时间、降低治疗时的机器跳数上有明显优势。

  • 标签: 鼻咽肿瘤 放射治疗 IMRT/Arc调强计划
  • 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.

  • 标签: twin-wire SUBMERGED-ARC welding weld metal with
  • 简介:这篇论文重新描述奥陶纪前(Pt_3)的特征在从方面ofpetrographic特征,岩石集合,石油化学,REE,痕量元素,铅同位素和大地构造的背景的云南省的Huimin-Manlai区域的变形火山岩。变形火山岩维持blasto-intergranularandblasto-andesitic质地;火山岩被basalt-andesite-daciteassemblage描绘;火山岩是在化学成分的basic-intermediate-intermediate-acid,属于半碱的岩石,与计算碱的系列并且拉斑玄武岩系列共存,并且他们被低TiO_2内容描绘;他们的REE分发模式theLREE丰富是使权利倾向的类型;火山岩在大阳离子元素被充实并且通常在Th充实并且部分在Ti,Cr和P弄空,属于从他们的Pb同位素组成看了的Gondwana类型;石油化学地,数据点主要在岛弧火山岩的地以内掉落。所有这些特征在学习的区域为原来的Tethysan岛弧火山岩的存在提供了新证据。

  • 标签: 澜沧江南部地带 原始特提斯岛弧 火山岩 新发育证据
  • 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。

  • 标签: CR2O3 电弧离子镀 涂料性能 微观结构 CRN S接口
  • 简介:Geochemical特征上面二叠(P_2)大陆人边缘的弧火山岩被描述,它最近在XiaodingxiandZangli的区域附近基于Yunxian-Lincang花岗石的东方方面以岩石集合,石油化学,REE,痕量元素,Pb同位素,大地构造的环境等等。火山岩集合被basalt-andesite-dacite统治,与次要的粗面岩andecite-trachyte;火山岩系列被计算碱的系列支配,与次要的tholleiite系列和碱的系列岩石;火山岩被高Al_2O_3和低TiO_2描绘,与显示出极其强壮的极性的K_2Ocontents;REE分发模式被LREEenrichment和使权利倾向的类型描绘;痕量元素和大阳离子元素高度被充实,Ti和Cr被弄空,并且P和Nb部分被弄空;Pb作文具有Gondwanatype;石油化学的点主要在岛弧火山岩的地以内掉落,有数据的设计的矛盾大陆人把边缘的火山岩指向南方Lancangjiang带和北方Lancangjiang带的南部的片断。这个大陆人边缘的弧火山岩带和在Changning-Menglian带的海洋山脉和海洋岛火山岩andophiolites,组成海洋山脉火山岩,在对分布式的ophiolite-arcrock-magmatic岩石带,显示Lancangjiang海洋的外壳向东代替ducted。这结果在在Lancangjiang带抑制thepaleo-Tethys的进化是很重要的。

  • 标签: 地球化学 岩石力学 火山岩 澜沧江
  • 作者: 王纯陈天佑
  • 学科:
  • 创建时间:2012-05-15
  • 出处:《学术研究》 2012年第5期
  • 机构:摘要:近年来,企业的社会责任报告已越来越受到国际、国内社会的广泛关注。并且已成为企业生产经营活动中必不可少的一部分。它不仅仅体现企业的社会责任,也有利于协调与企业与其利益相关团体的利益平衡,实现企业经济利益、环境保护以及社会利益的协调与统一发展。本文对中国石油与ARC石油公司社会责任报告的结构、披露的项目与内容、环境保护的投入、维护员工利益、参与社会公益事业等方面进行比较,进而阐述存在差异的成因,最后,对上市公司企业社会责任报告未来的发展提出一些策略性建议。
  • 简介:Thepresentstudyisconcernedwiththeeffectoffillermetalssuchasausteniticstainlesssteel,ferriticstainlesssteelandduplexstainlesssteelontensileandimpactpropertiesoftheferriticstainlesssteelconformingtoAISI409Mgrade.Rolledplatesof4mmthicknesswereusedasthebasematerialforpreparingsinglepassbuttweldedjoints.Tensileandimpactproperties,microhardness,microstructureandfracturesurfacemorphologyofthejointsfabricatedbyausteniticstainlesssteel,ferriticstainlesssteelandduplexstainlesssteelfillermetalswereevaluatedandtheresultswerereported.Fromthisinvestigation,itisfoundthatthejointsfabricatedbyduplexstainlesssteelfillermetalshowedhighertensilestrengthandhardnesscomparedtothejointsfabricatedbyausteniticandferriticstainlesssteelfillermetals.Jointsfabricatedbyausteniticstainlesssteelfillermetalexhibitedhigherductilityandimpacttoughnesscomparedwiththejointsfabricatedbyferriticstainlesssteelandduplexstainlesssteelfillermetals.

  • 标签: 铁素体不锈钢 冲击性能 电弧焊接 拉伸 奥氏体不锈钢 双相不锈钢
  • 简介:AbstractBackground:The effects of oral contrast agents (OCAs) on dosimetry have not been studied in detail. Therefore, this study aimed to examine the influence of OCAs on dose calculation in volumetric-modulated arc therapy plans for rectal cancer.Methods:From 2008 to 2016, computed tomography (CT) images were obtained from 33 rectal cancer patients administered OCA with or without intravenous contrast agent (ICA) and 14 patients who received no contrast agent. CT numbers of organs at risk were recorded and converted to electronic densities. Volumetric-modulated arc therapy plans were designed before and after the original densities were replaced with non-enhanced densities. Doses to the planned target volume (PTV) and organs at risk were compared between the plans.Results:OCA significantly increased the mean and maximum densities of the bowels, while the effects of ICA on these parameters depended on the blood supply of the organs. With OCA, the actual doses for PTV were significantly higher than planned and doses to the bowel increased significantly although moderately. However, the increase in the volume receiving a high-range doses was substantial (the absolute change of intestine volume receiving ≥52 Gy: 1.46 [0.05-3.99, cubic centimeter range: -6.74 to 128.12], the absolute change of colon volume receiving ≥50 Gy: 0.34 [0.01-1.53 cc, range: -0.08 to 3.80 cc]. Dose changes due to ICA were insignificant. Pearson correlation showed that dose changes were significantly correlated with a high intestinal volume within or near the PTV (ρ > 0.5, P < 0.05) and with the density of enhanced intestine (ρ > 0.3, P < 0.05).Conclusions:Contrast agents applied in simulation cause underestimation of doses in actual treatment. The overdose due to ICA was slight, while that due to OCA was moderate. The bowel volume receiving ≥50Gy was dramatically increased when OCA within the bowel was absent. Physicians should be aware of these issues if the original plan is barely within clinical tolerance or if a considerable volume of enhanced intestine is within or near the PTV.

  • 标签: Oral contrast agents Simulation Dosimetry Organ at risk Volumetric-modulated arc therapy
  • 简介:TheNeotethysplaysanimportantroleinshapingtheGangdesemagmaticbelt,southernTibet.However,theinitialtimeofspreadingandsubductionoftheNeotethysremainscontentious.Inthisstudy,asuiteoflateTriassiccumulatehornblendegabbrowasidentifiedinthesouthernmarginoftheGangdesemagmaticbelt.Thegabbroexhibitscumulatestructure,withhornblendeandplagioclaseastheprimarymineralphases.Isotopicdataindicateahydrousmagmasourcederivedfromadepletedmantlewedgethathasbeenmodifiedbyslabdehydration.Geochemicaldiscriminationssuggestthatthegabbrowasformedinanintraoceanicarcsetting,withcrystallizationagesofca.220-213Ma.Hornblende,hornblendelagioclaseandilmenitethermometersrevealthatthecrystallizationtemperatureof900-750°Cforthegabbro.Hornblendeandhornblende-plagioclasegeobarometersyieldanemplacementdepthatca.14.5-19.5km.ThisgabbroconstitutesalineofevidenceforanintraoceanicarcmagmatismthatiscoevalwiththecounterpartsinthesouthernTurkey,revealinganintraoceanicsubductionsystemwithintheNeotethysfromwesttoeastintheLateTriassicandthattheoceanizationoftheNeotethyswasmuchearlierthanpreviousexpectation.

  • 标签:
  • 简介:Micro-arcoxidation(MAO)processwascarriedoutinanoptimizeddualelectrolytesystemtofabricateacompact,smooth,andcorrosionresistantcoatingonZK60Mgalloy.Themicrostructuralcharacteristicsofcoatingwereinvestigatedbyscanningelectronmicroscopy(SEM)coupledwithanenergydispersivespectrometer(EDS)andX-raydiffraction(XRD).Testofmasslosswasconductedata3.5%NaClsolutiontoassesstheresistancetocorrosion.ThebondingstrengthbetweenthecoatingandZK60substratewasevaluatedusingscratchexperiment.TheresultsrevealthatMgAl2O4andMgOarethemainphasesofceramiccoatingobtainedinthedualelectrolytesystem.Thecorrosionrateofcoatingpreparedintheoptimizeddualelectrolyteisonly0.0061gám-2áh-1,whichdemonstratesexcellentcorrosionresistance.Thisismainlyduetothecompact,uniformcoatingwithhighbondingstrength.

  • 标签: ZK60镁合金 电解质体系 陶瓷涂层 微弧氧化 制备 表征
  • 简介:UltrabasicrocksintheMianxian-LueyangophioliticmelangezoneincludeharzburgiteanddunitewhichexhibitLREEdepletionwithremarkablepositiveEuanomaly.ThediabasedikeswarmshowsLREEenrichmentbutslightlynegativeEuanomaly.MetamorphosedvolcanicrockscanbedividedintotwogroupsintermsoftheirREEgeochemistryandtraceelementratiosofTi/V,Th/Ta,Th/YbandTa/Yb.OneisthsMORB-typebasaltwithLREEdepletion,representingthefragmentsofoceaniccrustandimplyinganassociationoftheMORB-typeophioliteandanancientoceanbasinbetweentheQinlingandYangtzeplatesduringtheMiddlePaleozoic-EarlyMesozoicera.Theotercomprisestheisland-arcvolcanicrocksincludingtholeiiticbasaltandalargeamountofcalc-alkalineintermediate-acicvolcanicrock,whichcouldnotbethecomponentoftheancientoceaniccrustbuttheresultofmagmatismatthecontinentalmargin.ThisindicatesthattheMianxian-Lueyanglimitedoceanbasinhadundergoneawholeprocessofdevelopment,evolutionandvanishingfromDevonian-CretaceoustoPermian.AndtheQinlingareahadbeconeanindependentlithosphericmicroplate,onthesouthernsideofwhichtherewereexhibitedthetectoniccharacteristicsofactivecontinentalmarginsduringtheLatePaleozoic-EarlyMesozoic.Thatistosay.theQinlingcannotbesimplyconsideredasaresultofcollisionbetweentheYangtzeandNorthChinaplates.

  • 标签: 地球化学 蛇绿岩 秦岭地区 火山岩 稀土元素 缝合带
  • 简介:ComparisonofmechanicalpropertiesinweldedjointforCO2arcweldingbyusingthemicro-sheartestandimpacttest¥ZhouLixia;WangShiyuanand?..

  • 标签: mechanical properties micro SHEAR TEST CO2
  • 简介:Amodellingstudyisperformedtocomparetheplasmaflowandheattransfercharacteristicsoflow-powerarc-heatedthrusters(arcjets)forthreedifferentpropellants:hydrogen,nitrogenandargon.Theall-speedSIMPLEalgorithmisemployedtosolvethegoverningequations,whichtakeintoaccounttheeffectsofcompressibility,LorentzforceandJouleheating,aswellasthetemperature-andpressure-dependenceofthegasproperties.Thetemperature,velocityandMachnumberdistributionscalculatedwithinthethrusternozzleobtainedwithdifferentpropellantgasesarecomparedforthesamethrusterstructure,dimensions,inlet-gasstagnantpressureandarccurrents.Thetemperaturedistributionsinthesolidregionoftheanode-nozzlewallarealsogiven.Itisfoundthattheflowandenergyconversionprocessesinthethrusternozzleshowmanysimilarfeaturesforallthreepropellants.Forexample,thepropellantisheatedmainlyinthenear-cathodeandconstrictorregion,withthehighestplasmatemperatureappearingnearthecathodetip;theflowtransitionfromthesubsonictosupersonicregimeoccurswithintheconstrictorregion;thehighestaxialvelocityappearsinsidethenozzle;andmostoftheinputpropellantflowstowardsthethrusterexitthroughthecoolergasregionneartheanode-nozzlewall.However,sincethepropertiesofhydrogen,nitrogenandargon,especiallytheirmolecularweights,specificenthalpiesandthermalconductivities,aredifferent,thereareappreciabledifferencesinarcjetperformance.Forexample,comparedtotheothertwopropellants,thehydrogenarcjetthrustershowsahigherplasmatemperatureinthearcregion,andhigheraxialvelocitybutlowertemperatureatthethrusterexit.Correspondingly,thehydrogenarcjetthrusterhasthehighestspecificimpulseandarcvoltageforthesameinletstagnantpressureandarccurrent.Thepredictionsofthemodellingarecomparedfavourablywithavailableexperimentalresults.

  • 标签: 电弧加热发动机 超音速流动 传热特性 推进器 氢气 氮气
  • 简介:【摘要】 目的 研究ARC换药流程在结直肠癌术后造口周围皮肤中的应用效果。方法  2019.6~2022.6在本院选取80例结直肠癌行造口术后患者,按照随机数字表法分为两组,各40例,采取常规换药流程为B组,采取ARC换药流程为A组,对比两组干预后效果。结果 A组较B组并发症发生率低(P<0.05);干预前两组变色-侵蚀-组织增生(DET)评分对比无差异(P>0.05),干预1个月、3个月后A组评分均低于B组(P<0.05)。结论 对结直肠癌造口术后患者给予ARC造口换药流程,有助于改善造口周围皮肤情况,并预防并发症发生,改善患者预后,值得应用。  

  • 标签: 结直肠癌 造口 换药流程