簡介：中文中文6512字出處出處INTERNATIONALJOURNALOFPRECISIONENGINEERINGANDMANUFACTURING,2010,1113947DEVELOPMENTOFA3AXISDESKTOPMILLINGMACHINEANDACNCSYSTEMUSINGADVANCEDMODERNCONTROLALGORITHMSKIMBS,ROSK,PARKJK1INTRODUCTIONASNEWFIELDSSUCHASITINFORMATIONTECHNOLOGY,BTBIOTECHNOLOGYANDNTNANOTECHNOLOGYEMERGEASADRIVINGFORCEINTHEINDUSTRY,THEINTERESTSINMICROFACTORYSYSTEMHAVEBEENGROWINGTHEMICROFACTORYISAMINIATURIZEDFLEXIBLEMANUFACTURINGSYSTEMWHICHCONSUMESMINIMALSPACEANDENERGYCOMPAREDTOTHECONVENTIONALONE,ANDITISDESIREDTOPRODUCEMICRO/MESOSIZEMECHANICALCOMPONENTSNECESSARYFORIT,BTANDNTAPPLICATIONSMAJORTECHNICALUNITSCONTRIBUTINGTOMICROMECHANICALMACHININGSYSTEMSARE,TONAMEAFEW,HIGHSPEEDSPINDLESYSTEMS,MICROHIGHPRECISIONFEEDINGSYSTEMS,CONTROLSYSTEMSTOGENERATECOORDINATEDMOTIONS,TOOLINGANDCHUCKINGSYSTEMS,FRAMEDESIGNANDMODULEALLOCATIONSCHEMESBASEDUPONOPTIMIZATIONFORHIGHSTIFFNESSRESEARCHERSHAVEBEENTRYINGTOPUTMICROTECHNOLOGIESTOGETHERTOBUILDMICROFACTORYSYSTEMSWHICHMAKEMICRO/MESOSIZEPRECISIONPARTSTOMEETTHENEEDSFROMTHEMANUFACTURINGINDUSTRY1INTHISPAPER,WEPRESENTAMINIATURIZED3AXISMILLINGMACHINEANDADEDICATEDCNCSYSTEMFORTHEMACHINETHE3AXISMILLINGMACHINEISCONSTRUCTEDASONEOFMICROFACTORYMODULEANDDESIGNEDTOPRODUCEHIGHPRECISIONMICROPARTSITHASADESKTOPSIZEOF200300200MM3ANDISSERVINGASOURTESTBEDMACHINEFROMFINITEELEMENTANALYSISANDANIMPACTHAMMERTEST,WEHAVEVERIFIEDTHATITHASAGOODSTRUCTURALSTIFFNESSANDHIGHNATURALFREQUENCIESAHIGHSPEEDAIRTURBINESPINDLEONTHEHORIZONTALZAXISCANRUNATUPTO160,000RPMTHIS3AXISMILLINGMACHINEWASPUTUNDERREALMACHININGTESTSANDITSUCCESSFULLYDEMONSTRATEDITSMACHININGCAPABILITIESACNCSYSTEMWASDEVELOPEDFOROPERATIONOFTHE3AXISDESKTOPMILLINGMACHINETHECNCSYSTEMINCLUDESAGCODEINTERPRETERWHICHCANPROCESSABASICSETOFGCODESANDMCODESINREALTIMETHECNCSYSTEMCONSISTSOFTWOPARTSTHEONEISAGRAPHICALUSERINTERFACEWHICHRUNSUNDERMICROSOFTWINDOWS,ANDTHEOTHERISADSPPROGRAMWHICHINTERPOLATESCOMMANDSANDEXECUTESAREALTIMESERVOCONTROLTWOPARTSCOMMUNICATEEACHOTHERTHROUGHADUALPORTRAMRANDOMACCESSMEMORYJOBASSIGNMENTSFORTHETWOPARTSAREDISCUSSEDINDETAILINTHISPAPERTOIMPROVETHEPERFORMANCEOFTHECNCSYSTEMFORTHE3AXISMILLINGMACHINEBEYONDTHETRADITIONALPIDTYPECONTROL,DIFFERENTCONTROLSCHEMESHAVEBEENTESTEDINCLUDINGH∞CONTROL,INPUTSHAPINGCONTROL,DISTURBANCEOBSERVERANDCROSSCOUPLEDCONTROLONTHE321STATICANDDYNAMICANALYSISFINITEELEMENTANALYSISWASDONETOINVESTIGATETHESTATICANDDYNAMICCHARACTERISTICSOFTHEDESIGNED3AXISMILLINGMACHINEUSINGAFINITEELEMENTMODELASSHOWNINFIG3THECOMPUTATIONALRESULTSSHOWEDTHATTHEDEFLECTIONDUETOITSOWNWEIGHTWASNEGLIGIBLEWHENA10NFORCEWASLOCATEDATTHEMACHININGPOSITIONINZDIRECTION,THENUMERICALRESULTSSHOWEDTHATTHEDISPLACEMENTCHANGEATTHEWORKTABLEWOULDBEABOUT007,ANDTHEBACKFAMEWOULDUNDERGOLESSTHAN002DEFLECTIONINZDIRECTIONITSEEMSTHATTHE3AXISMILLINGMACHINEHASGOODSTIFFNESSDUETOGOODFRAMEDESIGNANDAPAIROFSMALLLMGUIDESSUPPORTINGEACHXANDYDIRECTIONTHEMODALANALYSISREVEALEDMANYIMPORTANTDYNAMICMODESOFTHE3AXISMILLINGMACHINEWEUSEDTHEIMPACTHAMMERTESTTOVERIFYTHECOMPUTEDNATURALFREQUENCIESTHEMEASUREDNATURALFREQUENCIESDONOTEXACTLYMATCHTHECOMPUTEDONES,BUTTHEINDICATEDFREQUENCYRANGEFROMTHEFINITEELEMENTMODALANALYSISWASSIMILARTOTHATFROMTHEIMPACTHAMMERTESTFIG4ANDTABLE1SHOWTHEMEASUREDNATURALFREQUENCIESANDCORRESPONDINGFREQUENCYRESPONSEFUNCTIONOFTHE3AXISMILLINGMACHINEITCANBESEENTHATTHENATURALFREQUENCIESOFZAXISSTAGE,WHICHISSUPPOSEDTOBELOWINSTIFFNESSDUETOITSAIRBEARING,LOCATEATARANGEOF250390HZTHENATURALFREQUENCYOFTHEXYSTAGESHOWSATABOUT400AND710HZAND,FORTHEBACKFRAME,ITISAROUND440AND640HZITSEEMSTHATTHEDESIGNEDMINIATURIZED3AXISMILLINGMACHINEHASHIGHERNATURALFREQUENCIESTHANCONVENTIONALMACHINETOOLS

簡介：中文中文6420字，字，4000單詞，單詞，2萬英文字符萬英文字符出處出處OSSWALDD,WRNHMECHANICALSYSTEMANDCONTROLSYSTEMOFADEXTEROUSROBOTHANDC//2004機(jī)械手的機(jī)械和控制系統(tǒng)DOSSWALD，HWRN摘要最近，全球內(nèi)帶有多指夾子或手的機(jī)械人系統(tǒng)已經(jīng)發(fā)展起來了，多種方法應(yīng)用其上，有擬人化的和非擬人化的。不僅調(diào)查了這些系統(tǒng)的機(jī)械結(jié)構(gòu),而且還包括其必要的控制系統(tǒng)。如同人手一樣，這些機(jī)械人系統(tǒng)可以用它們的手去抓不同的物體，而不用改換夾子。這些機(jī)械手具備特殊的運(yùn)動(dòng)能力（比如小質(zhì)量和小慣性），這使被抓物體在機(jī)械手的工作范圍內(nèi)做更復(fù)雜、更精確的操作變得可能。這些復(fù)雜的操作被抓物體繞任意角度和軸旋轉(zhuǎn)。本文概述了這種機(jī)械手的一般設(shè)計(jì)方法，同時(shí)給出了此類機(jī)械手的一個(gè)示例，如卡爾斯魯厄靈巧手Ⅱ。本文末介紹了一些新的構(gòu)想，如利用液體驅(qū)動(dòng)器為類人型機(jī)器人設(shè)計(jì)一個(gè)全新的機(jī)械手。關(guān)鍵詞多指機(jī)械手；機(jī)器人手；精操作；機(jī)械系統(tǒng)；控制系統(tǒng)11引言引言2001年6月在德國卡爾斯魯厄開展的“人形機(jī)器人”特別研究，是為了開發(fā)在正常環(huán)境（如廚房或客廳）下能夠和人類合作和互動(dòng)的機(jī)器人系統(tǒng)。設(shè)計(jì)這些機(jī)器人系統(tǒng)是為了能夠在非專業(yè)、非工業(yè)的條件下（如身處多物之中），幫我們抓取不同尺寸、形狀和重量的物體。同時(shí)，它們必須能夠很好的操縱被抓物體。這種極強(qiáng)的靈活性只能通過一個(gè)適應(yīng)性極強(qiáng)的機(jī)械人手抓系統(tǒng)來獲得，即所謂的多指機(jī)械手或機(jī)器人手。上文提到的研究項(xiàng)目，就是要制造一個(gè)人形機(jī)器人，此機(jī)器人將裝備這種機(jī)器人手系統(tǒng)。這個(gè)新手將由兩個(gè)機(jī)構(gòu)合作制造，它們是卡爾斯魯厄大學(xué)的IPR（過程控制和機(jī)器人技術(shù)研究院）和C（計(jì)算機(jī)應(yīng)用科學(xué)研究院）。這兩個(gè)組織都有制造此種系統(tǒng)的相關(guān)經(jīng)驗(yàn)，但是稍有不同的觀點(diǎn)。IPR制造的卡爾斯魯厄靈巧手Ⅱ（如圖1所示），是一個(gè)四指相互獨(dú)立的手爪，我要確定手指的尺寸和安置位置，可以采用兩種方法擬人化和非擬人化。然后將取決與被操作的物體以及選擇何種期望的操作類型。擬人化的安置方式很容易從人手到機(jī)器人手轉(zhuǎn)移抓取意圖。但是每個(gè)手指不同的尺寸和不對(duì)稱的安置位置將增加加工費(fèi)用，并且是其控制系統(tǒng)變得更加復(fù)雜，因?yàn)槊總€(gè)手指都必須分別加以控制。對(duì)于相同手指的對(duì)稱布置，常采用非擬人化方法。因?yàn)橹恍杓庸ず蜆?gòu)建單一的“手指模塊”，因此可減少加工費(fèi)用，同時(shí)也可是控制系統(tǒng)簡化。32驅(qū)動(dòng)系統(tǒng)指關(guān)節(jié)的驅(qū)動(dòng)器對(duì)手的靈活度也有很大的影響，因?yàn)樗鼪Q定潛在的力量、精度及關(guān)節(jié)運(yùn)動(dòng)的速度。機(jī)械運(yùn)動(dòng)的兩個(gè)方面需加以考慮運(yùn)動(dòng)來源和運(yùn)動(dòng)方向。在這方面，文獻(xiàn)里描述了有幾種不同的方法，如文獻(xiàn)3中說可由液壓缸或氣壓缸產(chǎn)生運(yùn)動(dòng)，或者，正如大部分情況一樣使用電動(dòng)機(jī)。在多數(shù)情況下，運(yùn)動(dòng)驅(qū)動(dòng)器（如電機(jī)）太大而不能直接與相應(yīng)的指關(guān)節(jié)結(jié)合在一起，因此，這個(gè)運(yùn)動(dòng)必須由驅(qū)動(dòng)器（一般位于機(jī)器臂最后的連接點(diǎn)處）轉(zhuǎn)移過來。有幾種不同的方法可實(shí)現(xiàn)這種運(yùn)動(dòng)方式，如使用鍵、傳動(dòng)帶以及活動(dòng)軸。使用這種間接驅(qū)動(dòng)指關(guān)節(jié)的方法，或多或少地降低了整個(gè)系統(tǒng)的強(qiáng)度和精度，同時(shí)也使控制系統(tǒng)復(fù)雜化，因?yàn)槊扛种傅牟煌P(guān)節(jié)常常是機(jī)械地連在一起，但是在控制系統(tǒng)的軟件里卻要將它們分別獨(dú)立控制。由于具有這些缺點(diǎn)，因此小型化的運(yùn)動(dòng)驅(qū)動(dòng)器與指關(guān)節(jié)的直接融合就顯得相當(dāng)必要。33傳感系統(tǒng)機(jī)器手的傳感系統(tǒng)可將反饋信息從硬件傳給控制軟件。對(duì)手指或被抓物體建立一個(gè)閉環(huán)控制是很必要的。在機(jī)器手中使用了3種類型的傳感器1手爪狀態(tài)傳感器確定指關(guān)節(jié)和指尖的位置以及手指上的作用力情況。知道了指尖的精確位置將使精確控制變得可能。另外，知道手指作用在被抓物體上的力，就可以抓取易碎物件而不會(huì)打破它。2抓取狀態(tài)傳感器提供手指與被抓物體之間的接觸狀態(tài)信息。這種觸覺信息可在抓取過程中及時(shí)確定與物體第一次接觸的位置點(diǎn)，同時(shí)也可避免不正確的抓取，如抓到物體的邊緣和尖端。另外還能察覺到已抓物體是否滑落，從而避免物體因跌落而損壞。3物體狀態(tài)或姿態(tài)傳感器用于確定手指內(nèi)物體的形狀、位置和方向。如果在抓取物體之前并不清楚這些信息的情況下，這種傳感器是非常必要的。如果此傳感器還能作用

簡介：1SOUTHWESTPETROLEUMUNIVERSITYGRADUATIONTHESISCONTACTELIMINATIONINMECHANICALFACESEALSUSINGACTIVECONTROLGRADENAMESPECIALITYPROCESSEQUIPMENTANDCONTROLINSTRUCTORSOUTHWESTPETROLEUMUNIVERSITY201062們的位置并不在接觸的位置一定的權(quán)利。熱慣量也必須考慮到事件發(fā)生的預(yù)測和控制之間的時(shí)間延遲激活。整體而言，溫度測量是不是直接測量間隙，因此，這種方式才是最重要的它可能無法檢測到破壞，即情況下，接觸密封操作。在本研究中，減少偏差和相對(duì)減少了密封面接觸的可能性各種方式進(jìn)行了介紹和審議。第一次接觸是監(jiān)測從使用渦流探頭密封的動(dòng)態(tài)行為。這些提供適當(dāng)或不當(dāng)行為密封瞬時(shí)信息。然后，控制策略以及控制系統(tǒng)的開發(fā)和實(shí)施，以保持盡可能清除，相對(duì)偏差小，以保證非接觸式的FMR機(jī)械端面密封操作。22間歇面對(duì)面接觸間歇面對(duì)面接觸一個(gè)基本的描述和命名富達(dá)機(jī)械密封給出了圖1（見本運(yùn)動(dòng)學(xué)模型的細(xì)節(jié)5）。大壩是密封的轉(zhuǎn)子之間的傾斜面和固定定子（也都顯示在圖2）面積。為了減少磨損，其中之一的面孔通常是由較軟的材料，例如，碳石墨。在操作過程中面臨升空到一定中心線間隙，C，而較軟的材料也歪曲因?yàn)闄C(jī)械和熱變形，由錐角，Β代表注意，這兩個(gè)C和Β非常?。ㄒ晃⒚椎暮突《?，分別順序），因此，圖1不是比例顯示這些尺寸參數(shù)。腦脊液漏由于在密封的壓力降產(chǎn)生的情況將通過Β（如圖1。流從中心向周邊地區(qū)發(fā)生）造成的流體流動(dòng)匯流的差距。理想情況下，密封面垂直排列軸和相互平行。正如其名稱所暗示的，不應(yīng)該有任何的接觸過程中的非接觸式機(jī)械密封操作。然而，在現(xiàn)實(shí)中，在操作過程中接觸可能會(huì)出現(xiàn)由于大相對(duì)密封面之間的錯(cuò)位。相對(duì)偏差之間的密封面，Γ（見圖1），是制造和裝配公差，機(jī)械惡化，或在工藝操作，彎曲軸，密封面接觸等干擾的結(jié)果，不僅會(huì)產(chǎn)生影響力量，是不容易預(yù)測，但同時(shí)也增加了摩擦和磨損的端面和產(chǎn)生熱量的延長。

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簡介：鄭州航空工業(yè)管理學(xué)院英文翻譯2012屆機(jī)械設(shè)計(jì)制造及其在自動(dòng)化專業(yè)1006962班級(jí)姓名郝振興學(xué)號(hào)100696208指導(dǎo)教師賀紅霞職稱教授二О一二年三月十二日21THETIMEBACKGROUNDOFMATERIALPROCESSINGMACHINEINTHELONGSPANOFHISTORYOFHUMANPROGRESS,MANYTOOLS,MACHINESANDMETHODSWERECREATEDANDAVARIETYOFMATERIALSWITHDIFFERENTPROPERTIESWEREPROCESSEDMATERIALSANDITSPROCESSINGHAVEBECOMEONEOFPILLARANDDRIVINGFORCEOFMANKINDPROGRESSINPACEWITHMULTIPOLARCOMPETITIONINCURRENTWORLDANDPEOPLE’SSTRIVINGPERSEVERINGLYFORHAPPIERLIFE,MATERIALFUNCTIONGOESBEYONDUNCEASINGLYMEN’SKNOWLEDGEANDIMAGINATION,FOREXAMPLE,CRYPTICFUNCTIONMATERIAL,SEMICONDUCTORMATERIAL,ENERGYMATERIAL,VIBRATIONABSORPTIVEMATERIAL,SUPERSTRENGTHALUMINUMALLOYACCOUNTINGFOR70PERCENTOFAPPLICATIONOFAERONAUTICSANDSPACE,METALFOILOF4～5ΜM,DEEPDRAWINGPLATEWITHANISOTROPYBELOW1PERCENT,ELECTRONICALUMINUMFOILWITHMICROORIENTATIONUPTO95PERCENT,HEATRESISTINGALUMINUMALLOYWITHSUPERSTRONGSPECIFICSTRENGTHUSEDINAERONAUTICS,SPACEANDDEEPSEA,ETCTHUSSEVERALIMPORTANTDEVELOPMENTTRENDSWITHDISTINCTTIMEFEATURESINMATERIALPROCESSINGDOMAINARESHAPEDUPASFOLLOWS1CREATINGMATERIALPROCESSINGMACHINEWITHEXTRAORDINARYPHYSICALFIELDFORPROCESSINGMATERIALWITHSPECIALTEXTURESTRUCTURESANDFUNCTIONSFOREXAMPLE,APPLICATIONSOFTHERMALENERGYANDMECHANICALENERGYAREBREAKINGTHROUGHUNCEASINGLYTECHNOLOGYLIMIT,ANDSOMENONTRADITIONENERGY,SUCHASMICROWAVE,CHEMICALENERGY,BIOENERGY,ETC,AREINTRODUCEDINTOMATERIALPROCESSINGPROCEDUREONEAFTERANOTHER,SOTHATSOMEMATERIALPROCESSINGMACHINESWITHEXTRAORDINARYENERGYCIRCUMSTANCEAREPRODUCED2BREAKINGTHROUGHTRADITIONALPHYSICALLIMITSANDINTEGRATINGMELTING,SOLIDIFYING,PLASTICDEFORMATIONANDHEATTREATMENTTOOBTAINSPECIALFUNCTIONOFMATERIALANDCUTDOWNEXPENSES3FOREXAMPLE,NEARNETSHAPINGMATERIALPROCESSINGTECHNOLOGY,SUCHASFASTROLLING,SPRAYINGDEPOSITION,OVERPLASTICMOLDING,INJECTIONMOLDING,HIGHENERGYBEAM,ETC,ISAPPLIED3MATERIALPROCESSINGPROCESSISFORGEDAHEADINTHEDIRECTIONOFHIGHSPEED,HEAVYDUTYANDHIGHACCURACYONLINECONTROL,FORINSTANCE,THEROLLINGSPEEDGOESUPTO130MS1,THEDEFORMATIONPRESSURERISESUPTO300MPA,ACCURACYOFDIMENSIONUPTO01ΜM,ACCURACYOFSHAPEUPTO01I,STRENGTHACCURACYCOMESUPTO01MPAFORTHESEREASONS,ITISNECESSARYFORMATERIALPROCESSINGMACHINEDESIGNTHEORYTOINTEGRATEANDCOALESCEINGENIOUSLYCORRELATIVEFRONTIERSCIENCEANDTECHNOLOGYTOCREATEANDPRODUCESOMENEWCONCEPTMATERIALPROCESSINGMACHINEWITHFOLLOWINGFUNCTIONS

簡介：4570漢字，漢字，3380單詞，單詞，16萬英文字符萬英文字符出處出處RESEARCHJOURNALOFAPPLIEDSCIENCES,ENGINEERINGANDTECHNOLOGY5413021308,2013本科畢業(yè)論文外文文獻(xiàn)及譯文文獻(xiàn)、資料題目ANEXPERIMENTALANALYSISOFBRAKEEFFICIENCYUSINGFOURFLUIDSINADISCBRAKESYSTEM文獻(xiàn)、資料來源RESEARCHJOURNALOFAPPLIEDSCIENCES文獻(xiàn)、資料發(fā)表日期20120808院（部）機(jī)電工程學(xué)院專業(yè)班級(jí)姓名學(xué)號(hào)指導(dǎo)教師完成日期2AGAINSTTHERESISTANCESTHATOPPOSETHEVEHICLE’SMOTIONRELYINGONTHESERESISTANCESTOSLOWDOWNAVEHICLECOULDCAUSEMANYPROBLEMS,SOANADDITIONALRESISTANCECALLEDABRAKEISNEEDEDTOCONVERTTHEKINETICENERGYTOHEATENERGYATAFASTERRATEINORDERTOREDUCETHESPEEDOFTHEVEHICLEMCPHEEANDJOHNSON2007THISREDUCESTHESPEEDOFTHEVEHICLEATAFASTERRATEANDBRINGSTHEVEHICLETORESTWITHINTHESHORTESTPOSSIBLETIMEWHENTHEBRAKESAREAPPLIEDFROMTHEPOINTOFVIEWOFJOHNSONETAL2003MOSTAUTOMOTIVESYSTEMSINUSETODAYUTILIZEFRONTDISCBRAKES,BUTFOURWHEELDISCSYSTEMSAREALSOCOMMONINDISCBRAKES,THEROTORROTATESWITHTHEWHEELANDTHEPADSMOVEOUTTORUBTHEROTORWHENTHEBRAKESAREAPPLIEDMOSTDISCBRAKESUSEFLOATINGCALIPERSTHECALIPERSLIDESINANDOUTASTHEBRAKESAREAPPLIEDANDRELEASEDTHEPISTONMOVESTHEINSIDEPADOUTANDPUSHESTHEOUTSIDEPADINTOTHEROTORBYSLIDINGTHECALIPERBACKTOWARDTHEROTORTHEUSEOFDISCBRAKESTOREDUCESPEEDORBRINGTHEVEHICLETORESTWHENINMOTIONCANNOTBEOVEREMPHASIZEDIFTHESAFETYOFTHEOCCUPANTISTOBEGUARANTEEDHEINZ1999TOBRINGAVEHICLETOASTOP,THEDISCBRAKESHAVETOABSORBALLTHEENERGYGIVENTOTHEVEHICLEBYTHEENGINEANDTHATDUETOTHEMOMENTUMOFTHEVEHICLETHISENERGYMUSTTHENBEDISSIPATEDINMOSTVEHICLEDISCBRAKES,THEENERGYISABSORBEDBYFRICTION,CONVERTEDINTOHEATANDTHEHEATDISSIPATEDTOTHESURROUNDINGAIRTHOMS,1988ASTHEENERGYISABSORBED,THEVEHICLEISSLOWEDDOWNINOTHERWORDS,ITSMOTIONISRETARDEDTHEBRAKESMUSTALSOPULLUPTHEVEHICLESMOOTHLYANDINASTRAIGHTLINETOBRINGTHEVEHICLETOASTOPPOSITIONITISTHEREFOREVERYIMPORTANTTHATTHEDISCBRAKESOFVEHICLESOPERATEWITHTHEHIGHESTEFFICIENCYTHISCOULDREDUCETHERATEOFACCIDENTSDUETOBRAKEFAILURESOTHATLIFEANDPROPERTYCOULDBEPRESERVEDANDALSOTOENSURETHATOCCUPANTSOFTHESECOMMERCIALVEHICLESGOABOUTTHEIRNORMALLIVESWITHOUTANYFEAROFBEINGINVOLVEDINANACCIDENTAVAILABLECRASHDATAINGHANASUGGESTSTHATABOUT1,900PERSONSAREKILLEDANNUALLYINROADTRAFFICCRASHESAFUKAARETAL,2008ANDTHATMORETHAN40OFTHEROADTRAFFICFATALITIESAREOCCUPANTSOFCARS,BUSESANDTRUCKSMOSTOFTENTHANNOT,SOMEOFTHEROADACCIDENTSINVOLVINGCOMMERCIALVEHICLES,SUCHASTHEMINIBUSESHAVEBEENATTRIBUTEDTOTHEFAILUREOFTHEDISCBRAKESTHEREASONFORTESTINGTHEVISCOSITYOFTHESEBRAKEFLUIDS,ESPECIALLYTHATOFTHE

簡介：SWITCHEDRELUCTANCEMOTORSDRIVEFORTHEELECTRICALTRACTIONINSHEARERABSTRACTTHEPAPERPRESENTEDTHEDOUBLESWITCHEDRELUCTANCEMOTORSPARALLELDRIVESYSTEMFORTHEELECTRICALTRACTIONINSHEARERTHESYSTEMCOMPONENTS,SUCHASTHESWITCHEDRELUCTANCEMOTOR,THEMAINCIRCUITOFTHEPOWERCONVERTERANDTHECONTROLLER,WEREDESCRIBEDTHECONTROLSTRATEGIESOFTHECLOSEDLOOPROTORSPEEDCONTROLWITHPIALGORITHMANDBALANCINGTHEDISTRIBUTIONOFTHELOADSWITHFUZZYLOGICALGORITHMWEREGIVENTHETESTSRESULTSWEREALSOPRESENTEDITISSHOWNTHATTHERELATIVEDEVIATIONOFTHEAVERAGEDCSUPPLIEDCURRENTOFTHEPOWERCONVERTERINTHESWITCHEDRELUCTANCEMOTOR1ANDINTHESWITCHEDRELUCTANCEMOTOR2ISWITHIN?10KEYWORDSSWITCHEDRELUCTANCEMOTORCONTROLSHEARERCOALMINEELECTRICALDRIVEIINTRODUCTIONTHEUNDERGROUNDSURROUNDINGSOFTHECOALMINESAREVERYEXECRABLEONESIDE,ITISTHEMOIST,HIGHDUSTANDINFLAMMABLESURROUNDINGSONTHEOTHERSIDE,THESPACEOFROADWAYISLIMITEDSINCEITISNECESSARYTOSAVETHEINVESTMENTOFEXPLOITINGCOALMINESSOTHATITISDIFFICULTTOMAINTAINTHEEQUIPMENTSINTHEMODERNCOALMINES,THEAUTOMATIZATIONEQUIPMENTSCOULDBEUSEDWIDELYTHEFAULTSOFTHEAUTOMATIZATIONEQUIPMENTSCOULDAFFECTTHEPRODUCTIONANDTHEBENEFITOFTHECOALMINESTHESHEARERISTHEMININGEQUIPMENTTHATCOALCOULDBECUTFROMTHECOALWALLTHETRADITIONALSHEARERWASDRIVENBYTHEHYDROSTATICTRANSMISSIONSYSTEMTHEFAULTRATIOOFTHEHYDROSTATICTRANSMISSIONSYSTEMISHIGHSINCETHEFLUIDINHYDROSTATICTRANSMISSIONSYSTEMCOULDBEPOLLUTEDEASILYTHEFAULTSOFTHEHYDROSTATICTRANSMISSIONSYSTEMCOULDAFFECTTHEPRODUCTIONANDTHEBENEFITOFTHECOALMINESDIRECTLYTHEFAULTRATIOOFTHEMOTORDRIVESYSTEMISLOWERTHANTHATOFTHEHYDROSTATICTRANSMISSIONSYSTEM,BUTITISDIFFICULTTOCOOLTHEMOTORDRIVESYSTEMINCOALMINESSINCETHEMOTORDRIVESYSTEMSHOULDBEINSTALLEDWITHINTHEFLAMEPROOFENCLOSUREFORSAFETYPROTECTIONTHEMOTORDRIVESYSTEMISALSOONEOFTHEPIVOTALPARTSINTHEAUTOMATIZATIONEQUIPMENTSTHEDEVELOPMENTOFTHENOVELTYPESOFTHEMOTORDRIVESYSTEMHADBEENATTACHEDIMPORTANCETOBYTHECOALMINESTHESWITCHEDRELUCTANCEMOTORDRIVECOULDBECOMEACPOWERSOURCEWASCERTIFICATEDANDSUPPLIEDTOTHEPOWERCONVERTERTHEMAINCIRCUITOFTHEPOWERCONVERTERWASSHOWNINFIGURE2INTHECONTROLLER,THEREWERETHEROTORPOSITIONDETECTIONCIRCUIT,THECOMMUTATIONCIRCUIT,THECURRENTANDVOLTAGEPROTECTIONCIRCUIT,THEMAINSWITCHES’GATEDRIVERCIRCUITANDTHEDIGITALCONTROLLERFORROTORSPEEDCLOSEDLOOPANDBALANCINGTHEDISTRIBUTIONOFTHELOADSIIICONTROLSTRATEGYTHETWOSWITCHEDRELUCTANCEMOTORCOULDALLDRIVETHESHEARERBYTHETRANSMISSIONOUTFITINTHESAMETRACTIONGUIDEWAYSOTHATTHEROTORSPEEDOFTHETWOSWITCHEDRELUCTANCEMOTORSCOULDBESYNCHRONIZEDTHECLOSEDLOOPROTORSPEEDCONTROLOFTHEDOUBLESWITCHEDRELUCTANCEMOTORSPARALLELDRIVESYSTEMCOULDBEIMPLEMENTEDBYPIALGORITHMINTHESWITCHEDRELUCTANCEMOTOR1,THETRIGGEREDSIGNALSOFTHEMAINSWITCHESINTHEPOWERCONVERTERAREMODULATEDBYPWMSIGNAL,THECOMPARISONOFTHEGIVENROTORSPEEDANDTHEPRACTICALROTORSPEEDAREMADEANDTHEDUTYRATIOOFPWMSIGNALAREREGULATEDASFOLLOWS,

簡介：ZZZZZZZ大學(xué)畢業(yè)設(shè)計(jì)（論文）外文文獻(xiàn)學(xué)院XXXXXXXX專業(yè)班級(jí)XXXXXX學(xué)生姓名XXXXX指導(dǎo)教師XXXXXXTHEMOUNTEDGRINDINGTOOLSWHEELSHAVEBEENWIDELYUSEDINCONVENTIONALMOLDANDDIEFINISHINGINDUSTRIESTHEGEOMETRICMODELOFMOUNTEDGRINDINGTOOLSFORAUTOMATEDSURFACEFINISHINGPROCESSESWASINTRODUCEDINAFINISHINGPROCESSMODEOFSPHERICALGRINDINGTOOLSFORAUTOMATEDSURFACEFINISHINGSYSTEMSWASDEVELOPEDINGRINDINGSPEED,DEPTHOFCUT,FEEDRATE,ANDWHEELPROPERTIESSUCHASABRASIVEMATERIALANDABRASIVEGRAINSIZE,ARETHEDOMINANTPARAMETERSFORTHESPHERICALGRINDINGPROCESS,ASSHOWNINFIG1THEOPTIMALSPHERICALGRINDINGPARAMETERSFORTHEINJECTIONMOLDSTEELHAVENOTYETBEENINVESTIGATEDBASEDINTHELITERATUREFIG1SCHEMATICDIAGRAMOFTHESPHERICALGRINDINGPROCESSINRECENTYEARS,SOMERESEARCHHASBEENCARRIEDOUTINDETERMININGTHEOPTIMALPARAMETERSOFTHEBALLBURNISHINGPROCESSFIG2FORINSTANCE,ITHASBEENFOUNDTHATPLASTICDEFORMATIONONTHEWORKPIECESURFACECANBEREDUCEDBYUSINGATUNGSTENCARBIDEBALLORAROLLER,THUSIMPROVINGTHESURFACEROUGHNESS,SURFACEHARDNESS,ANDFATIGUERESISTANCETHEBURNISHINGPROCESSISACCOMPLISHEDBYMACHININGCENTERSANDLATHESTHEMAINBURNISHINGPARAMETERSHAVINGSIGNIFICANTEFFECTSONTHESURFACEROUGHNESSAREBALLORROLLERMATERIAL,BURNISHINGFORCE,FEEDRATE,BURNISHINGSPEED,LUBRICATION,ANDNUMBEROFBURNISHINGPASSES,AMONGOTHERSTHEOPTIMALSURFACEBURNISHINGPARAMETERSFORTHEPLASTICINJECTIONMOLDSTEELPDS5WEREACOMBINATIONOFGREASELUBRICANT,THE

簡介：中文中文4240字出處出處CHENW,LUOX,SUH,ETALANINTEGRATEDSYSTEMFORULTRAPRECISIONMACHINETOOLDESIGNINCONCEPTUALANDFUNDAMENTALDESIGNSTAGEJINTERNATIONALJOURNALOFADVANCEDMANUFACTURINGTECHNOLOGY,201517畢業(yè)設(shè)計(jì)畢業(yè)設(shè)計(jì)論文論文外文資料翻譯外文資料翻譯原文題目目超精密機(jī)床設(shè)計(jì)的概念和基本設(shè)計(jì)階段的綜合系統(tǒng)原文來源源施普林格出版社倫敦2015學(xué)生姓名名學(xué)號(hào)號(hào)所在院所在院系部部機(jī)械工程學(xué)院專業(yè)名稱稱機(jī)械設(shè)計(jì)制造及其自動(dòng)化（機(jī)械設(shè)計(jì)）具體的功能模塊，包括結(jié)構(gòu)設(shè)計(jì)與分析、結(jié)構(gòu)設(shè)計(jì)、結(jié)構(gòu)分析和支持模塊。該系統(tǒng)快速、方便地進(jìn)行機(jī)床結(jié)構(gòu)設(shè)計(jì)。WOONG等人利用設(shè)計(jì)知識(shí)開發(fā)了一種高效、系統(tǒng)的機(jī)床設(shè)計(jì)智能化軟件系統(tǒng)。CHEN等人使用集成的設(shè)計(jì)方法開發(fā)了一種超精密飛切機(jī)床三種配置（水平，龍門，塔式）是從配置庫中選擇的候選配置的設(shè)計(jì)階段，根據(jù)機(jī)床的功能要求，考慮動(dòng)態(tài)性能的最佳配置選擇。而在以往的研究中，對(duì)精密機(jī)床的研究主要集中在機(jī)床的詳細(xì)設(shè)計(jì)和性能分析方面，系統(tǒng)的概念和基本設(shè)計(jì)方法很少有報(bào)道。在本文中，闡述了對(duì)概念和基本設(shè)計(jì)階段用于縮短設(shè)計(jì)時(shí)間、提高精密機(jī)床的可靠性超精密機(jī)床設(shè)計(jì)的集成系統(tǒng)重要性。22超精密機(jī)床設(shè)計(jì)集成系統(tǒng)超精密機(jī)床設(shè)計(jì)集成系統(tǒng)21機(jī)床的概念和基本設(shè)計(jì)過程精密機(jī)床是一種高標(biāo)準(zhǔn)的精密系統(tǒng)，以維持所需的精度，生產(chǎn)率和可重復(fù)性。一個(gè)機(jī)器的精度相對(duì)于工件表面和相對(duì)的結(jié)構(gòu)和動(dòng)態(tài)循環(huán)的精密切削工具的定位精度的影響，是基本也是重要的機(jī)械設(shè)計(jì)。因此，機(jī)床的結(jié)構(gòu)設(shè)計(jì)階段必須考慮機(jī)床的剛度循環(huán)和機(jī)床運(yùn)動(dòng)誤差的問題。此外，機(jī)床振動(dòng)的動(dòng)態(tài)特性和熱性能是高精度加工的關(guān)鍵問題之一。由于動(dòng)態(tài)和熱性能的機(jī)器受機(jī)器的配置影響較大，所以，評(píng)估應(yīng)該在設(shè)計(jì)階段的早期。然而，只有少數(shù)制造商使用評(píng)估工具，以檢查配置的合格性?？傊?，在概念和基本設(shè)計(jì)階段，必須考慮精密機(jī)床設(shè)計(jì)的主要因素有以下幾點(diǎn)機(jī)床的剛度預(yù)算，動(dòng)態(tài)性能，熱性能和機(jī)床的誤差預(yù)算。機(jī)床結(jié)構(gòu)的概念和基本設(shè)計(jì)過程分為四個(gè)步驟，即，目標(biāo)，建模，分析和選擇如圖1所示，提出了幾種配置提出了幾種配置。

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簡介：1附錄附錄1英文原文SELECTIONOFOPTIMUMTOOLGEOMETRYANDCUTTINGCONDITIONSUSINGASURFACEROUGHNESSPREDICTIONMODELFORENDMILLINGABSTRACTINFLUENCEOFTOOLGEOMETRYONTHEQUALITYOFSURFACEPRODUCEDISWELLKNOWNANDHENCEANYATTEMPTTOASSESSTHEPERFORMANCEOFENDMILLINGSHOULDINCLUDETHETOOLGEOMETRYINTHEPRESENTWORK,EXPERIMENTALSTUDIESHAVEBEENCONDUCTEDTOSEETHEEFFECTOFTOOLGEOMETRYRADIALRAKEANGLEANDNOSERADIUSANDCUTTINGCONDITIONSCUTTINGSPEEDANDFEEDRATEONTHEMACHININGPERFORMANCEDURINGENDMILLINGOFMEDIUMCARBONSTEELTHEFIRSTANDSECONDORDERMATHEMATICALMODELS,INTERMSOFMACHININGPARAMETERS,WEREDEVELOPEDFORSURFACEROUGHNESSPREDICTIONUSINGRESPONSESURFACEMETHODOLOGYRSMONTHEBASISOFEXPERIMENTALRESULTSTHEMODELSELECTEDFOROPTIMIZATIONHASBEENVALIDATEDWITHTHECHISQUARETESTTHESIGNIFICANCEOFTHESEPARAMETERSONSURFACEROUGHNESSHASBEENESTABLISHEDWITHANALYSISOFVARIANCEANATTEMPTHASALSOBEENMADETOOPTIMIZETHESURFACEROUGHNESSPREDICTIONMODELUSINGGENETICALGORITHMSGATHEGAPROGRAMGIVESMINIMUMVALUESOFSURFACEROUGHNESSANDTHEIRRESPECTIVEOPTIMALCONDITIONS1INTRODUCTIONENDMILLINGISONEOFTHEMOSTCOMMONLYUSEDMETALREMOVALOPERATIONSININDUSTRYBECAUSEOFITSABILITYTOREMOVEMATERIALFASTERGIVINGREASONABLYGOODSURFACEQUALITYITISUSEDINAVARIETYOFMANUFACTURINGINDUSTRIESINCLUDINGAEROSPACEANDAUTOMOTIVESECTORS,WHEREQUALITYISANIMPORTANTFACTORINTHEPRODUCTIONOFSLOTS,POCKETS,PRECISIONMOULDSANDDIESGREATERATTENTIONISGIVENTODIMENSIONALACCURACYANDSURFACEROUGHNESSOFPRODUCTSBYTHEINDUSTRYTHESEDAYSMOREOVER,SURFACEFINISHINFLUENCESMECHANICALPROPERTIESSUCHASFATIGUEBEHAVIOUR,WEAR,CORROSION,LUBRICATIONANDELECTRICALCONDUCTIVITYTHUS,MEASURINGANDCHARACTERIZINGSURFACEFINISHCANBECONSIDEREDFORPREDICTINGMACHININGPERFORMANCESURFACEFINISHRESULTINGFROMTURNINGOPERATIONSHASTRADITIONALLYRECEIVEDCONSIDERABLERESEARCHATTENTION,WHEREASTHATOFMACHININGPROCESSESUSINGMULTIPOINTCUTTERS,REQUIRESATTENTIONBYRESEARCHERSASTHESEPROCESSESINVOLVELARGENUMBEROFPARAMETERS,ITWOULDBEDIFFICULTTOCORRELATESURFACEFINISHWITHOTHERPARAMETERSJUSTBYCONDUCTINGEXPERIMENTSMODELLINGHELPSTOUNDERSTANDTHISKINDOFPROCESSBETTERTHOUGHSOMEAMOUNTOFWORKHASBEENCARRIEDOUTTODEVELOPSURFACEFINISHPREDICTIONMODELSINTHEPAST,THEEFFECTOFTOOLGEOMETRYHASRECEIVEDLITTLEATTENTIONHOWEVER,THERADIALRAKEANGLEHASAMAJORAFFECTONTHE3ALTHOUGHTHEDIFFERENCEBETWEENTHEMREGARDINGTHESURFACEROUGHNESSWASLARGEBAYOUMIETAL4HAVESTUDIEDTHEAFFECTOFTHETOOLROTATIONANGLE,FEEDRATEANDCUTTINGSPEEDONTHEMECHANISTICPROCESSPARAMETERSPRESSURE,FRICTIONPARAMETERFORENDMILLINGOPERATIONWITHTHREECOMMERCIALLYAVAILABLEWORKPIECEMATERIALS,11L17FREEMACHININGSTEEL,62353FREEMACHININGBRASSAND2024ALUMINIUMUSINGASINGLEFLUTEDHSSMILLINGCUTTERITHASBEENFOUNDTHATPRESSUREANDFRICTIONACTONTHECHIP–TOOLINTERFACEDECREASEWITHTHEINCREASEOFFEEDRATEANDWITHTHEDECREASEOFTHEFLOWANGLE,WHILETHECUTTINGSPEEDHASANEGLIGIBLEEFFECTONSOMEOFTHEMATERIALDEPENDENTPARAMETERSPROCESSPARAMETERSARESUMMARIZEDINTOEMPIRICALEQUATIONSASFUNCTIONSOFFEEDRATEANDTOOLROTATIONANGLEFOREACHWORKMATERIALHOWEVER,RESEARCHERSHAVENOTTAKENINTOACCOUNTTHEEFFECTSOFCUTTINGCONDITIONSANDTOOLGEOMETRYSIMULTANEOUSLYBESIDESTHESESTUDIESHAVENOTCONSIDEREDTHEOPTIMIZATIONOFTHECUTTINGPROCESSASENDMILLINGISAPROCESSWHICHINVOLVESALARGENUMBERFPARAMETERS,COMBINEDINFLUENCEOFTHESIGNIFICANTPARAMETERSANONLYBEOBTAINEDBYMODELLINGMANSOURANDABDALLAETAL5HAVEDEVELOPEDASURFACEROUGHNESSMODELFORTHEENDMILLINGOFEN32MASEMIFREECUTTINGCARBONCASEHARDENINGSTEELWITHIMPROVEDMERCHANTABILITYTHEMATHEMATICALMODELHASBEENDEVELOPEDINTERMSOFCUTTINGSPEED,FEEDRATEANDAXIALDEPTHOFCUTTHEAFFECTOFTHESEPARAMETERSONTHESURFACEROUGHNESSHASBEENCARRIEDOUTUSINGRESPONSESURFACEMETHODOLOGYRSMAFIRSTORDEREQUATIONCOVERINGTHESPEEDRANGEOF30–35M/MINANDASECONDORDEREQUATIONCOVERINGTHESPEEDRANGEOF24–38M/MINWEREDEVELOPEDUNDERDRYMACHININGCONDITIONSALAUDDINETAL6DEVELOPEDASURFACEROUGHNESSMODELUSINGRSMFORTHEENDMILLINGOF190BHNSTEELFIRSTANDSECONDORDERMODELSWERECONSTRUCTEDALONGWITHCONTOURGRAPHSFORTHESELECTIONOFTHEPROPERCOMBINATIONOFCUTTINGSPEEDANDFEEDTOINCREASETHEMETALREMOVALRATEWITHOUTSACRIFICINGSURFACEQUALITYHASMIETAL7ALSOUSEDTHERSMMODELFORASSESSINGTHEINFLUENCEOFTHEWORKPIECEMATERIALONTHESURFACEROUGHNESSOFTHEMACHINEDSURFACESTHEMODELWASDEVELOPEDFORMILLINGOPERATIONBYCONDUCTINGEXPERIMENTSONSTEELSPECIMENSTHEEXPRESSIONSHOWS,THERELATIONSHIPBETWEENTHESURFACEROUGHNESSANDTHEVARIOUSPARAMETERSNAMELY,THECUTTINGSPEED,FEEDANDDEPTHOFCUTTHEABOVEMODELSHAVENOTCONSIDEREDTHEAFFECTOFTOOLGEOMETRYONSURFACEROUGHNESSSINCETHETURNOFTHECENTURYQUITEALARGENUMBEROFATTEMPTSHAVEBEENMADETOFINDOPTIMUMVALUESOFMACHININGPARAMETERSUSESOFMANYMETHODSHAVEBEENREPORTEDINTHELITERATURETOSOLVEOPTIMIZATIONPROBLEMSFORMACHININGPARAMETERSJAINANDJAIN8HAVEUSEDNEURALNETWORKSFORMODELINGANDOPTIMIZINGTHEMACHININGCONDITIONSTHERESULTSHAVEBEENVALIDATEDBYCOMPARINGTHEOPTIMIZEDMACHININGCONDITIONSOBTAINEDUSINGGENETICALGORITHMSSURESHETAL9HAVEDEVELOPEDASURFACEROUGHNESSPREDICTIONMODELFORTURNINGMILDSTEELUSINGARESPONSESURFACEMETHODOLOGYTOPRODUCETHEFACTORAFFECTSOFTHEINDIVIDUALPROCESS

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簡介：1本科生畢業(yè)設(shè)計(jì)外文資料翻譯題目社區(qū)民意調(diào)查平臺(tái)設(shè)計(jì)與實(shí)現(xiàn)專業(yè)計(jì)算機(jī)科學(xué)與技術(shù)班級(jí)XXX姓名XXX指導(dǎo)教師指導(dǎo)教師XXX（高級(jí)實(shí)驗(yàn)師）所在學(xué)院所在學(xué)院信息學(xué)院附件1外文資料翻譯譯文2外文原文3ACCORDINGTOTHESAMPLINGMETHODSFORANALYZINGTHEQUESTIONNAIREDATA,RESEARCHERSCANUSENOTONLYDESCRIPTIVESTATISTICSMETHODSTODESCRIBETHEBASICDISTRIBUTIONOFTHESAMPLES,BUTALSOINFERENTIALSTATISTICSMETHODSTOINFERTHEREALHUMANBEHAVIORANDSOCIALPHENOMENONSIGNIFICANCEOFGROUPDIFFERENCESISONEOFTHEFOURTYPESOFTHERESEARCHQUESTIONSTABACHNICKFIDELL,1996FOREXAMPLE,INAQUESTIONNAIRESURVEYFORELEMENTARYSCHOOLSTUDENTS,“ISTHEREASIGNIFICANTDIFFERENCEBETWEENBOYSANDGIRLSABOUTTHEHOURSTHEYACCESSTHEINTERNETEVERYWEEK”ISANINTERESTINGPHENOMENONTHATRESEARCHERSWANTTOKNOWINTHEQUESTIONNAIREANALYSIS,HOWTOFINDASTATISTICALLYSIGNIFICANTDIFFERENCEBETWEENTWOORMOREGROUPSINACONTINUOUSMEASUREISONEOFTHEMAJORRESEARCHISSUESINTHETRADITIONALQUANTITATIVERESEARCH,THERESEARCHERSWILLFIRSTLYPROPOSESEVERALHYPOTHESESOFTHESUBJECTACCORDINGTOTHEIREXPERIENCES,ANDTHENDETERMINEWHETHERTHEREEXISTSASTATISTICALSIGNIFICANCEINSOMEHYPOTHESISINATRYANDERRORMANNERTHEQUALITYOFTHERESULTUSINGTHEMANNER,OFCOURSE,ISINACCORDANCEWITHTHEQUALITYOFTHEHYPOTHESES,ANDTHEPROCESSOFFINDINGTHESTATISTICALLYSIGNIFICANTDIFFERENCESISHIGHLYDEPENDENTONRESEARCHERSINTUITIONANDEXPERIENCEFOREXAMPLE,INAQUESTIONNAIRESURVEYOFELEMENTARYSCHOOLSTUDENTS’INTERNETUSAGEBEHAVIOR,ARESEARCHERMIGHTMAKEAHYPOTHESIS,“THEREISASTATISTICALLYSIGNIFICANTDIFFERENCEBETWEENDIFFERENTGENDERSABOUTTHEHOURSTHEYACCESSTHEINTERNETEVERYWEEK,“ANDTHENUSEAPPROPRIATEINFERENTIALSTATISTICSMETHODACCORDINGTOHIS/HERKNOWLEDGEOFSTATISTICSTOTESTTHISHYPOTHESISWITHOUTMAKINGTHEHYPOTHESIS,THEDIFFERENCECANNOTBEFOUNDEVENIFITREALLYEXISTSTHEREFORE,HOWTOACQUIRETHEKNOWLEDGEANDEXPERIENCEOFSENIORRESEARCHERSMIGHTBEHELPFULFORTHEJUNIORRESEARCHERSBESIDES,GRANULARITYOFORIGINALQUESTIONNAIREDATAMAYNOTBEGOODENOUGHTOFINDTHESTATISTICALLYSIGNIFICANTDIFFERENCESFOREXAMPLE,INAQUESTIONNAIRESURVEYOFELEMENTARYSCHOOLSTUDENTSINTERNETUSAGEBEHAVIOR,IFTHEREISNOSIGNIFICANTDIFFERENCEBETWEENDIFFERENTRESIDENTREGIONSABOUTTHEHOURSSTUDENTSACCESSTHEINTERNETEVERYWEEK,THERESEARCHERMIGHTCONCLUDETHEREISNOSIGNIFICANTDIFFERENCEBETWEENDIFFERENTRESIDENTREGIONSHOWEVER,EACHREGIONMAYCONTAINSEVERALCOUNTIESINGEOGRAPHYBYDRILLINGDOWNTHESTUDENTSRESIDENTDIMENSIONTOLOWERLEVELSOFGRANULARITY,ITISSTILLPOSSIBLETOFINDASIGNIFICANTDIFFERENCEBETWEENDIFFERENTCOUNTIESWHENRESEARCHERSANALYZEAQUESTIONNAIREDATA,THEYHAVETOMAKESOMEHYPOTHESESOFTHEPOSSIBLESTATISTICALLYSIGNIFICANTDIFFERENCESFROMTHEDATAANDUSETHEIRKNOWLEDGELIKERULESTOSELECTTHE

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簡介：1中文中文7600字出處出處RENEWABLEANDSUSTAINABLEENERGYREVIEWS1320092175–2180RENEWABLEANDSUSTAINABLEENERGYREVIEWSHIGHBRIGHTNESSLEDSENERGYEFFICIENTLIGHTINGSOURCESANDTHEIRPOTENTIALININDOORPLANTCULTIVATIONNAICHIAYEHA,JENPINGCHUNGABSTRACTTHERAPIDDEVELOPMENTOFOPTOELECTRONICTECHNOLOGYSINCEMID1980HASSIGNIFICANTLYENHANCEDTHEBRIGHTNESSANDEFFICIENCYOFLIGHTEMITTINGDIODESLEDSLEDSHAVELONGBEENPROPOSEDASAPRIMARYLIGHTSOURCEFORSPACEBASEDPLANTRESEARCHCHAMBERORBIOREGENERATIVELIFESUPPORTSYSTEMSTHERAISINGCOSTOFENERGYALSOMAKESTHEUSEOFLEDSINCOMMERCIALCROPCULTUREIMMINENTWITHTHEIRENERGYEFFICIENCY,LEDSHAVEOPENEDNEWPERSPECTIVESFOROPTIMIZINGTHEENERGYCONVERSIONANDTHENUTRIENTSUPPLYBOTHONANDOFFEARTHTHEPOTENTIALSOFLEDASANEFFECTIVELIGHTSOURCEFORINDOORAGRICULTURALPRODUCTIONHAVEBEENEXPLOREDTOAGREATEXTENTTHEREAREMANYRESEARCHESTHATUSELEDSTOSUPPORTPLANTGROWTHINCONTROLLEDENVIRONMENTSSUCHASPLANTTISSUECULTUREROOMANDGROWTHCHAMBERTHISPAPERPROVIDESABRIEFDEVELOPMENTHISTORYOFLEDSANDABROADBASEREVIEWONLEDAPPLICATIONSININDOORPLANTCULTIVATIONSINCE1990CONTENTS1INTRODUCTION2LEDDEVELOPMENT3COLORRATIOSANDPHOTOSYNTHESIS4LEDSANDINDOORPLANTCULTIVATION41PLANTTISSUECULTUREANDGROWTH42SPACEAGRICULTURE843ALGACULTURE44PLANTDISEASEREDUCTION5INTERMITTENTANDPHOTOPERIODLIGHTINGANDENERGYSAVING6CONCLUSION1INTRODUCTIONWITHIMPACTSOFCLIMATECHANGE,ISSUESSUCHASMOREFREQUENTANDSERIOUSDROUGHTS,FLOODS,ANDSTORMSASWELLASPESTANDDISEASESAREBECOMINGMORESERIOUSTHREATSTOAGRICULTURETHESETHREATSALONGWITHSHORTAGEOFFOODSUPPLYMAKEPEOPLETURNTOINDOORANDURBANFARMINGSUCHASVERTICALFARMINGFORHELPWITHPROPERLIGHTING,INDOORAGRICULTUREELIMINATESWEATHERRELATEDCROPFAILURESDUETODROUGHTSANDFLOODSTOPROVIDEYEARROUNDCROPPRODUCTION,WHICHASSISTINSUPPLYINGFOODINCITIESWITHSURGINGPOPULATIONSANDINAREASOFSEVEREENVIRONMENTALCONDITIONS3FIG1LEDDEVELOPMENTBEGANWITHINFRAREDANDREDDEVICESMADEWITHGALLIUMARSENIDEADVANCESINMATERIALSSCIENCEHAVEMADEPOSSIBLETHEPRODUCTIONOFDEVICESWITHEVERSHORTERWAVELENGTHS,PRODUCINGLIGHTINAVARIETYOFCOLORSJMARGOLINREPORTEDTHATTHEFIRSTKNOWNLIGHTEMITTINGSOLIDSTATEDIODEWASMADEIN1907BYHJROUNDNOPRACTICALUSEOFROUND’SDIODEWASMADEFORSEVERALDECADESUNTILTHEINVENTIONOFTHEFIRSTPRACTICALLEDBYNICKHOLONYAK,JRIN1962HISLEDSBECAMECOMMERCIALLYAVAILABLEINLATE1960STHESEGAASPLEDSCOMBINETHREEPRIMARYELEMENTSGALLIUM,ARSENICANDPHOSPHORUSTOPROVIDEA655NMREDLIGHTWITHBRIGHTNESSLEVELSOFAPPROXIMATELY1–10MCDAT20MAASTHELUMINOUSINTENSITYWASLOW,THESELEDSWEREONLYUSEDINAFEWAPPLICATIONS,PRIMARILYASINDICATORSFOLLOWINGGAASP,GAPGALLIUMPHOSPHIDEREDLEDSWEREDEVELOPEDTHESEDEVICESEXHIBITVERYHIGHQUANTUMEFFICIENCIESATLOWCURRENTSASLEDTECHNOLOGYPROGRESSEDTHROUGHTHE1970S,ADDITIONALCOLORSANDWAVELENGTHSBECAMEAVAILABLETHEMOSTCOMMONMATERIALSWEREGAPGREENANDRED,GAASPORANGE,ANDHIGHEFFICIENCYREDANDGAASPYELLOWTHETRENDTOWARDSMOREPRACTICALAPPLICATIONSSUCHASINCALCULATORS,DIGITALWATCHES,ANDTESTEQUIPMENTALSOBEGANTODEVELOPASTHELEDMATERIALSTECHNOLOGYBECAMEMOREADVANCED,THELIGHTOUTPUTWASINCREASED,ANDLEDSBECAMEBRIGHTENOUGHTOBEUSEDFORILLUMINATIONIN1980SANEWMATERIAL,GAALASGALLIUMALUMINUMARSENIDEWASDEVELOPEDFOLLOWEDBYARAPIDGROWTHINTHEUSEOFLEDSGAALASTECHNOLOGYPROVIDESSUPERIOR