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外文翻译
沈阳工业大学
本科生毕业设计(论文)外文翻译
题目:
AnewSemiconductorThermometerforGeothermalMeasurements
学院:
信息科学与工程学院
专业班级:
电信1002班
学生姓名:
张野
指导教师:
林成武
2014年3月16日
AnewSemiconductorThermometerforGeothermalMeasurements
BySATYABRATADATTA1)
Summary:
Aportablesolidstatedevicedesignedandconstructedforthemeasurementoftemperaturevariationwithdepthinsideaboreholeisdescribed.Saturationcurrent(whichishighlydependentonambienttemperature)inareversebiasedPNjunctionhasbeenutilisedforthepurposeofmeasurement.Theequipmentisinexpensiveandpossessesseveraladvantagesoverothertypesofinstrumentsforgeothermalmeasurementregardingsimplicityinconstructionandoperation.
1.Introduction
Usually,thermistorsareutilisedastemperaturepick-upelementinboreholegeothermalmeasurements[1]2).Thisischieflybecausethermistorshavehighnegativetemperaturecoefficientofresistance.Inthemethodofmeasurementwiththermistor,aresistancebridgeisusedinassociationwithanoscillator[2]oraD.C.[3]voltagesource.Athermistorwiththecableformsonearmofthebridge.Out-of-balancevolt-ageduetochangeinthermistorresistancecausedbytemperaturevariationsisnotedafteramplificationwhenthethermistorwiththecableisloweredintheborehole.Thetemperatureundermeasurementisthenfoundfromacalibrationchartorcurveshowingunbalancevoltageversustemperaturepreviouslyconstructedinthelaboratoryundercontrolledconditions.Sourcesoferrorinthismethodofmeasurementarelargelyduetodriftinthethermistorandamplifiercharacteristics,andalsoduetoundesirablechangesincableandotherbridgearmresistances.
Thedesignandconstructionoftheequipmentdescribedinthispaperwasunder-takenfortheuseofaglacierexpeditionpartyoftheGeologicalSurveyofIndiatostudytemperaturevariationswithdepthinsideboreholesinglacier.Obviously,theequipmenttosuitthepurposeshouldbelightandsimpleinconstruction,anditsperformanceshouldnotbesusceptibletoadversesurfaceclimaticvariationslikelytobeencountered.
2.Description
Theworkingprincipleoftheinstrumentisasfollows:
Thecurrent(I)flowingthroughaPNjunctionisgivenbytherelation
I≈i0(eV/VT-1),
(1)
1)GeophysicsDivision,GeologicalSurveyofIndia,Calcutta-16(India).-ThispaperispublishedbythekindpermissionoftheDirectorGeneral,GeologicalSurveyofIndia.
2)NumbersinbracketsrefertoReferences,page126.
Whereio=junctionsaturationcurrent,
V=appliedjunctionvoltagewhichis+veintheforwarddirection,
VT=Junctionbarriervoltage=(KT)/q,
K=Boltzmanconstant,
T=Junctiontemperaturein0K
q=electroniccharge.
Whenthejunctionappliedvoltageisintheforwarddirection(+ve),theexponentialterminequation
(1)predominatesandasaresultthecurrentincreasesexponent-tallywithappliedvoltage.ForappliedvoltageseveraltimeslargerthanVT(VTisabout26mVat250C)inthereversedirection,thecurrentbecomesindependentoftheappliedvoltageandpracticallyremainsconstantatthesaturationcurrentleveli0solongasbreakdownoravalanchevoltageisnotexceeded.ThissaturationcurrentisactuallycausedbytheflowofthermallygeneratedminoritycarriersinthePandNregions.Therefore,itsvalueishighlydependentontemperatureandinactualpracticeincreasesexponentiallywithit.Intheinstrumentdesignedthishighlytemperaturedependentnatureofthesaturationcurrentwhichispracticallyunaffectedbythemagnitudeofsupplyvoltagehasbeenutilisedforthepurposeofmeasurement.
Theelectroniccircuitdiagramoftheinstrumentisshowninfigure1.Tworeversebiasedbase-collectorPNjunctionsofGermaniumtransistorsareconnectedinparallelsothatindividualsaturationcurrentsofthetwojunctionsaddup.Thesetwotransistorsinparallelformtemperaturesensingheadandareinthermalcontactwiththeboreholefluid.ResultantsaturationcurrentisthenamplifiedbyathirdtransistorwhichactsasaD.C.currentamplifier.Theamplifiedcurrentplusthetotalsaturationcurrentthroughthesensingjunctionsismeasuredbyasensitivemicroammeter.Thecurrentflowingthroughthismeteristhereforegivenby2(1+β)io,whereβisthecurrentamplifyingfactoroftheamplifier.
Vol.61,1965/I1)AnewSemiconductorThermometer
Aphotographofthecompleteinstrumentconsistingofthesurfaceequipment,cablewoundinthewinchandalsotheprobeisshowninfigure3.Thetwosensingtransistorstogetherwiththeamplifyingtransistoraremountedinaperspexblockwhichisapoorthermalconductorwiththemetalcapsprotrudingoutsidesothattheycanattainambienttemperatureinshorttime.Thisperspexblockiscementedattheendofaperfectlywatertightbrasstube.Athincoppercup(notshowninthephotograph)inthermalcontactwiththetransistorsisusedtoprotectthetransistorsfromanypossibledamagewhentheprobeisloweredinsidetheborehole.Thesurfaceequipmentconsistsofavoltagesupplyfromtwo1.5voltdrycellsinserieswithasensitivemicroammeterwithadjustableshuntssothatitcanmeasurecurrentfortemperaturevariationsfrom--180Cto+100CAtwo-corecablefromthesurfaceequipmentisledintothebrasstubeprobeandthecableentryintotheprobeismadefullywatertightbya0-ringseal.Necessaryelectricalconnectionshavebeenmadeinsidetheprobeandextremecarehasbeentakentoensurethatnosurfaceleakagecurrentflowsbetweenthecableconductorsortransistorleads.Thecalibrationcurveillustratingvariationoflog10i,whereiisthecurrentinµAthroughthemeterversustemperature(t)in0Cconstructedinthelaboratorywiththehelpofatemperaturebathisshowninfigure2.Thecalibrationcurveispracticallyastraightlineandisfoundtofittheempiricalrelationi=34e0.17t
ItiswellknownthattheperformanceofaD.C.transistorcurrentamplifierishighlyaffectedbythechangesintheambienttemperature.Thisismainlyduetotheshiftintheoperatingpointcausedbythechangesincurrentgainfactorandi0withtemperature.Forthis,theamplifiercannotbeincorporatedinthesurfaceequipmentwhichmaybesubjectedtounforeseentemperaturefluctuationsduringoperation.Toavoidtheeffectofamplifierdriftonthetemperaturemeasurement,theamplifyingtransistorhasalsobeenmountedinthepersepexblockatthe
probeendandtheresultantvariationofiwhichisequalto2(1+β)i0isnotedformeasurement.Foroperation,theprobewiththecableisloweredinsidetheboreholeuptotherequireddepthandthecurrentindicatedbythemicroammeterinthesteadystatewhichisreachedinabouttwominute'stime,isnoted.Thetemperatureundermeasurementisthendeducedfromthecalibrationcurve.
3.Conclusionanddiscussion
Thepresentinstrumenthasbeenspeciallydesignedforthestudyoftemperatureinsideaglacierborehole.Themeasurementaccuracyisdependentonthetemperatureundermeasurement.Atlowtemperature(near--200C)whenthecurrentiissmall,themeasurementaccuracyismainlylimitedbythemetersensitivity.Thelimitationinaccuracyatsuchlowtemperatureisalsoduetothefactthatthesurfaceleakagecurrent,howeversmallitmaybemade,becomescomparabletothesaturationcurrent.Theinstrumentdesignedcartconvenientlybeusedfortemperaturemeasurementsbetween—150Cto+100C.Measurementaccuracyisabout0.20C,0.80Cand0.050Cwhenthetemperatureundermeasurementsis--100C,O0Cand+50Crespectively.Theinstrumentmaybemademoresensitivebyincreasingthenumberofsensingtransistorsinparalleloralternativelybyaddingadditionalcurrentamplifyingstagesincascade.Thesameprinciplemaybeutilisedforhighertemperaturemeasurements.Itmustbementionedinthisconnectionthatthemaximumtemperatureshouldnotexceedthenormalworkingtemperature{about500CforGermaniumtransister)rangeofthetransistorused.WithSilicontransistor,however,thisrangemaybeincreasedappreciably.Forthemeasurementofhighertemperature,itmaybenecessarytoreducethesupplyvoitageinordertocutdownthecollectordissipationrateoftheamplifier.
Thisinstrumentsuffersfromthecommondrawbackduetodriftastheothertypewhichutilisesthermistorcausedbytheunavoidablechangeinthecharacteristicofthesensingelementduetoaging.Effectofthisdriftinthepresentinstrumentissmallasthecalibrationcurvehasbeenfoundtorepeatitselfwithoutanyappreciabledeviation.Similarinstrumentwithsomemodifications,ifnecessarymayalsobeutilisedforthestudyoftemperaturevariationswithdepthinoceanographicinvestigations.
4.Acknowledgements
TheauthorisgratefultoSriL.N.KAILASAM,ChiefGeophysicistforhiskeeninterestintheworkandencouragement,andtoSriD.GUPTASARMA,SeniorGeophysicistforhishelpfulsuggestions.
REFERENCES
[1]A.D.MISENERandA.E.BECK,Themeasurementofheatflowoverland,MethodsandTechniquesinGeophys.1(1960),10.
[2]G.N.NEWS~EADandA.E.BECk,BoreholeTemperaturemeasuringEquipmentandGeothermalfluxinTasmania,Austral.J.Phys.6(1953),480.
[3]A.C.ANDERSON,Temperaturemeasurementwiththermistors,ElectronicandRadioEngineer35(1958),80.
(Received12thMay1965)
一种新型的测量地热的半导体温度计
BySATYABRATADATTA1
摘要:
一种便携式的呈固态的被设计和构造成,为了测量温度变化在钻井内部较深的区域在如下被描述。
饱和电流(很大程度上取决于于周围环境的温度)在反向偏置的PN结中已经被用来达到测量的目的。
设备并不是十分昂贵并且具有一些优势在设备的简易的结构和操作方面上,同比于其他类型的测量地热的测量仪器。
1.介绍
通常来说,热敏电阻被用作温度的取样元件在钻井的地热温度测量[1])。
这主要是因为热敏电阻有很高的负温度阻抗系数。
在用热敏阻抗测量温度的方法中,一个电阻桥被用来与一个振荡器和一个直流电压源相连接。
一个带有电
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