学科分类
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64 个结果
  • 简介:Ahigh-repetitionratemasteroscillatorpoweramplifierpumpedwithlaserdiodes(LDs)isreported.Aninjectionseedingsingle-frequencyelectro-opticalQ-switchedNd:YAGlaserisusedasanoscillator,andaconductivelycooledNd:YAGzigzagslabwithabounce-pumpedarchitectureisutilizedasapoweramplifier.Pulseenergiesofover800mJat1064nmand400mJat532nm,correspondingtoaveragepowersof200and100W,respectively,areachievedwitha12.6-nspulsewidthat250Hz.Outputfrequencyfluctuationsandsingle-frequencyoperationarefurthermonitored.Experimentalresultsrevealthattheproposedsystem,whichfeaturesasingle-passamplifiedconfiguration,isapromisingdesignforspace-basedapplications.

  • 标签: Nd YAG激光器 激光二极管泵浦 主振荡器 锯齿形 主放大器
  • 简介:Themasterdesignof300kt/avinylacetateunitattheSichuanVinylonPlanthaspassedreview,andconstructionofthisunitwillbekickedoffsoon.ThisprojectisakeyassociatedprojectenvisagedbytheprojectfortransmissionofSichuangastoEasternChina,anditsfeasibilitystudyreporthasbeenapprovedfollowingtheenvironmentassessmentconductedbytheStateBureau

  • 标签: 环境保护 煤气 气体排放 石业化工行业
  • 简介:摘要:换热器芯体的检测[1]主要是检查其流通板与翅片叠放正确与否。将机器视觉识别技术应用于换热器芯体叠片的检测,基于vision master研发的换热器芯体的自动化检测的机器视觉识别方案能够高效的完成检测判断,由机器自主完成,适用于大规模工业生产,使换热器芯体的检测完全实现了自动化,极大地提高了检测效率和准确率。

  • 标签: 换热器芯体,机器视觉识别,图像检测
  • 简介:TheFe-Ti-Nmateralloywaspreparedthroughthein-situreactionofnitrogengaswiththeFe-Timelt.ScanningelectronmicroscoperesultsshowthattheparticlesuniformlydistributedintheironmatrixwereTiN.ThedeliberatelypreparedFe-Ti-Nmasteralloywasemployedforthe409Lferriticstainlesssteelinanattempttorefinetheas-castsolidificationstructure.ItwasfoundthattheeffectivenessofFe-Ti-Nmasteralloyonrefiningoftheas-cast409Lferriticstainlesssteelwasaffectedbyadditionlevel,holdingtimeandmeltstemperature.Itwasfoundthattheaverageequiaxedgrainsizedecreasedfrom1503μmto303μm,theproportionofequiaxedgrainzoneincreasedfrom14%to100%withincreasingtheFe-Ti-Nmasteralloyadditionlevelto2.5%.Theproportionofequiaxedgraindecreasedfrom85%to4%asthesolidificationtemperatureincreasedfrom1803Kto1883K.Whentheholdingtimereachedto8min,thesolidificationstructuresof409Lferriticstainlesssteelshowextremepointsintheproportionofequiaxedgrain.Itisclearthatthegrainrefiningefficiencygraduallyfadeawaywiththeincreasingoftheholdingtimeattheverybeginning.However,whentheholdingtimecontinuestoincreaseandexceedstheextremepoint,thegrainrefiningefficiencyoftheFe-Ti-Nmasteralloyrecoveredtoacertaindegree.Theexperimentalresultsmentionedabovehavebeenanalyzedintermsofthermodynamics.Underappropriateconditions,theFe-Ti-Nmasteralloyusedforgrainrefinementofthesolidificationstructureof409Lferriticstainlesssteelmayhavegoodprospectsforindustrialapplications.

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  • 简介:Theterm'physicalliteracy'isgainingtractioninmanycountriesandinstitutionsasagoalforphysicaleducation.Thispaperexplorestheconceptofphysicalliteracyandhighlightsthefoundationalworkinthisarea,particularlythatofMargaretWhitehead.Therelationshipofphysicalliteracytophysicaleducationisalsodiscussedwithpotentialramificationsforteachersandlearnerswhoadoptphysicalliteracyasthegoalofthesubjectarea.

  • 标签: 体育教育 素养 物理 学习 期望 牵引力
  • 简介:Wereportonthehigh-poweramplificationofa1064nmlinearlypolarizedlaserinanall-fiberpolarizationmaintainedmasteroscillatorpoweramplifier,whichcanoperateatanoutputpowerlevelof1.3kW.Thebeamquality(M~2)wasmeasuredtobe<1.2atfullpoweroperation.Thepolarizationextinctionrateofthefiberamplifierwasmeasuredtobeabove94%beforemodeinstabilities(MIs)setin,whichreducedtoabout90%aftertheonsetofMI.ThepowerscalingcapabilityofstrategiesforsuppressingMIisanalyzedbasedonasemianalyticalmodel,thetheoreticalresultsofwhichagreewiththeexperimentalresults.ItshowsthatmitigatingMIbycoilingthegainfiberisaneffectiveandpracticalmethodinstandarddouble-claddinglargemodeareafiber,and,bytightcoilingofthegainfibertotheradiusof5.5cm,theMIthresholdcanbeincreasedtothreetimeshigherthanthatwithoutcoilingorloosecoiling.Experimentalstudieshavebeencarriedouttoverifytheidea,whichhasprovedthatMIwassuppressedsuccessfullyintheamplifierbypropercoiling.

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  • 简介:该文结合实例介绍了使用I—DEASMasterSeries对大型箱体零件进行刚强度分析的过程中,在实体建模、单元选择、网格划分、施加约束条件和加载方面应当注意的一些问题,最后讲了如何提取箱体零件的刚强度指标。

  • 标签: 计算机辅助设计 实体造型 有限元分析
  • 简介:通过实践这些技巧来找到一灵活的、特制的适合自己学习风格的记忆系统。这里所述的20个技巧分为4种类型,每种都代表着一种增进记忆力的基本原理。这四种类型,简述如下:组织:组织得有条理的信息容易被发现。第1~3条

  • 标签: 记忆方法 创造联想 背诵 复述 学习时间
  • 简介:一向以上乘质料和天文台机芯为傲的TITONIMasterSeries首次推出令人惊喜万分的天文台月相腕表,作为本年度的压轴。这一精致表款充分体现了高超制表技艺的精髓,完美地融合了精准计时功能与雅致的设计。

  • 标签: 天文台 腕表 月相 梅花 瑞士
  • 简介:AdditionofAl-5Ti-1Balloytomoltenaluminumalloyscanrefineα-Algrainseffectivelyandtherebyimprovetheirstrengthandtoughness.TiAl3andTiB2inAl-5Ti-1Balloyarethemainsecondary-phaseparticlesforrefinement,whiletheunderstandingontheeffectoftheirsizesonα-Algrainrefinementcontinuestobefragmented.Therefore,Al-5Ti-1Balloyswithvarioussizesandmorphologiesofthesecondary-phaseparticleswerepreparedbyequalchannelangularpressing(ECAP).Evolutionofthesecondary-phaseparticlesduringECAPprocessandtheirimpactonα-AlgrainrefinementwerestudiedbyX-raydiffractionandscanningelectronmicroscope(SEM).ResultsshowthatduringtheECAPprocess,micro-cracksfirstlyappearedinsideTiAl3particlesandthengraduallyexpanded,whichresultedincontinuousrefinementofTiAl3particles.Inaddition,micro-distributionuniformityofTiB2particleswasimprovedduetotheimpingementofTiAl3particlestoTiB2clustersduringdeformation.ExcessivelylargesizesofTiAl3particleswouldreducethenumberofeffectiveheterogeneousnucleusandthusresultedinpoorgrainrefinementeffectiveness.Moreover,excessivelysmallTiAl3particleswouldreduceinhibitoryfactorsforgraingrowthQandweakengrainrefinementeffectiveness.Therefore,anoptimalsizerangeof18-22μmforTiAl3particleswassuggested.

  • 标签: Equal channel ANGULAR PRESSING process Secondary
  • 简介:【摘要】目的:探讨白内障患者术前的人工晶体度数测量方法,观察 IOL Master与 A超在其中的应用效果。方法:选取 2017年 4月 ~2018年 10月期间于我院接受手术治疗的 130例白内障患者作为研究对象,分为观察组( IOL Master)和对照组( A超)各 65例,观察两组患者在检测结果上的差异性。结果:与对照组相比,观察组患者在散光≤ 1.00D时的平均屈光误差 [( 0.39±0.13) D<( 0.51±0.27) D]、散光≤ 2.00D时的平均屈光误差 [( 0.37±0.15) D<( 0.93±0.33) D]以及散光≤ 3.00D时的平均屈光误差 [( 0.61±0.19) D<( 1.87±0.51) D]相对更低( P< 0.05)。结论:在白内障患者接受手术治疗前,应用 IOL Master进行人工晶体度数的测量,能够获得准确的测量结果,进而为手术治疗安全、顺利的进行提供保障,其应用效果明显优于 A超。

  • 标签: IOL Master A超 白内障术 人工晶体度数
  • 简介:[摘要] 目的:分析IOL Master700应用于白内障患者人工晶体屈光度测量的准确性。方法:2021年1月~2023年1月,选取本院诊治的105例白内障患者作为对象。围术期检查,分别使用眼科超声仪、角膜曲率计和IOL Master700系统,对比各项测量结果。结果:1)IOL法和常规法对术前眼部AL、ACD、Km、W-W参数的测定结果接近,无统计学差异(P>0.05)。2)不同轴长的患者中,IOL法和常规法对术前眼轴长度的测定结果接近,无统计学差异(P>0.05)。3)轴长L>26 mm的患者中,IOL法测量得到的术后绝对屈光误差值明显小于常规法,有统计学差异(P<0.05)。结论:白内障患者人工晶体屈光度测量时,使用IOL Master700具有较高的准确性,值得推广。

  • 标签: 白内障 人工晶体 屈光度测量 准确性
  • 简介:IPM是世界有害植物治理的中心课题,也是一种利用定期监测以决定是否及何时需要进行治理的有害生物控制方法。它使用了许多策略来管理有害生物的数量并却实践了其攻克有害生物治理以及滥用杀虫剂等方面许多议题的承诺。利用IPM,我们不仅能了解有害生物的生命周期和习性,从而采用预防性措施、推广能够更好地抵抗有害生物破坏的健康植物还能通过使用多种有害生物破坏方法减少杀虫剂使用量等。IPM从环保、经济的理念出发,为草坪业开辟出了一条可持续发展之路。

  • 标签: IPM 综合治理 实践 病虫害 有害生物 概念