JB/T 54351-1999 射吸式焊炬、割炬 产品质量分等
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基本信息
标准名称: | 射吸式焊炬、割炬 产品质量分等 |
中标分类: | 机械 >> 加工工艺 >> 焊接与切割 |
替代情况: | JB/T 54351-1994 |
发布日期: | 1999-12-30 |
实施日期: | 2000-06-01 |
首发日期: | 1900-01-01 |
作废日期: | 1900-01-01 |
出版日期: | 1900-01-01 |
页数: | 19页 |
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所属分类: 机械 加工工艺 焊接与切割
下载地址: 点击此处下载
基本信息
标准名称: | 静电复印机用涂氟塑料定影辊 技术条件 |
中标分类: | 仪器、仪表 >> 电影、照相、缩微、复印设备 >> 缩微复印机械 |
替代情况: | 原标准号ZB N47012-1990 |
发布部门: | 全国复印机械标委会 |
发布日期: | 1999-08-06 |
实施日期: | 2000-01-01 |
首发日期: | 1900-01-01 |
作废日期: | 1900-01-01 |
归口单位: | 全国复印机械标准化技术委员会 |
出版日期: | 1900-01-01 |
页数: | 5 页 |
批文号: | 国机管[1999]422 |
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所属分类: 仪器 仪表 电影 照相 缩微 复印设备 缩微复印机械
【英文标准名称】:StandardTestMethodforFieldMeasurementofSoundPowerLevelbytheTwo-SurfaceMethod【原文标准名称】:双表面法现场测量声功率级的标准试验方法
【标准号】:ASTME1124-2010
【标准状态】:现行
【国别】:美国
【发布日期】:2010
【实施或试行日期】:
【发布单位】:美国材料与试验协会(US-ASTM)
【起草单位】:E33.08
【标准类型】:(TestMethod)
【标准水平】:()
【中文主题词】:
【英文主题词】:fieldsoundpower;industrialnoise;machinerynoise;soundpower;two-surfacemethod;Acousticaltests;Ambientsoundpressurelevels;Bandfiltersets;Concavemeasurementsurfaces;Conformalmeasurementsurfaces;Convexmeasurementsurfaces;Fieldtes
【摘要】:Thefunctionandoperationofequipmentinthefieldoftenprecludethemeasurementofthefree-fieldsoundpressurelevelsofasinglepieceofequipmentintheabsenceofinterferingsoundfromotherequipmentoperatingatthesametime.Thetwo-surfacemethodwillprovide,inmostcases,areliableestimateofthenormalsoundpowerlevelsofaspecimenoperatinginanadverseenvironment.Thistestmethodisintendedforuseinthefieldinthepresenceofwhatisnormallyregardedasinterferingbackgroundnoise.ThistestmethodisbasedupontheworkofHubner,andDiehl,butdiffersfromallothercurrentsoundpowermeasurementproceduresbyrequiringsimultaneousmeasurementatbothconformalsurfacesandbyresolvingtime-averagedsoundpressurelevelsatbothsurfacestowithin0.1dB.Thesetwofeatures,simultaneousrecordingand0.1dBresolution,enablesourcesoundpowertobecalculatedwhenthedirectsoundfieldofthesourceisactuallylowerinlevelthantheambientnoise.Theuseofthistestmethodisexpectedtobeprimarilyfortherelativeassessmentofthesoundpowerfromsimilarsourcesorforthepredictionofsoundlevelsinaplantbaseduponmeasurementsofsimilarsourcesinanotherplant.Thistestmethodisbelievedtobecapableofyieldingareasonablygoodestimateofabsolutepowerlevelwithpropercareofapplicationandfullconformancetotheprovisionsofthisprocedure.Thetwo-surfacemethodisapplicableonlywhenthetwomeasurementsurfacescanbephysicallyselectedtoproducepositivevaluesofthedifferenceinaveragesoundpressurelevel.Thatis,theinnersurfacesoundpressurelevelminustheoutersurfacesoundpressurelevelmustbeatleast+0.1dB.Thislimitationappliestoeachfrequencybandandeachconstituentsurfaceareainvestigated.Onlythefrequencybandinwhichazeroornegativedifferenceoccursisitconsideredinvalidandusuallyadjacentbandswillbevalid.Inpractice,onlyrarelywillallthreeone-thirdoctavebandsofagivenoctaveyieldinvaliddataatallconstituentareas.Therefore,lessthancompleteresultsarepermissiblewhenone-thirdoctaveanalysisisusedandfulloctaveresultsarereported.Thetwo-surfacemethodmaynotproduceresultswhentestingsomeverylargemachinesinveryreverberantroomsorinroomshavingavolumelessthanabout20timesthespaceenclosedbyanenvelopearoundthelargerdimensionsofthemachine.Insuchcases,thesoundpressurelevelclosetothemachinemaynotdecreaseinanyregularwaywithincreasingdistancefromamachinesurface,makingitimpossibletoselecttwomeasurementsurfacesproducingpositivedifferencesofsoundpressurelevel.1.1Thistestmethodcoversthefield,orinsitumeasurementofsoundpowerlevelbythetwo-surfacemethod.Thetestmethodisdesignedtominimizetheeffectsofreverberantconditions,directivityofthenoisesourceunderconsideration,andtheeffectsofambientnoisefromothernearbyequipmentoperatingatthesametime.1.2Thisstandarddoesnotpurporttoaddressallofthesafetyconcerns,ifany,associatedwithitsuse.Itistheresponsibilityoftheuserofthisstandardtoestablishappropriatesafetyandhealthpracticesanddeterminetheapplicabilityofregulatorylimitationspriortouse.
【中国标准分类号】:A42
【国际标准分类号】:17_140_0
【页数】:7P.;A4
【正文语种】:英语