Proceedings of Meetings on Acoustics Volume 19, 2013 http://acousticalsociety.org/ ICA 2013 Montreal Montreal, Canada 2-7 June 2013 Architectural Acoustics Session 2pAAb: Dah-You Maa: His Contributions and Life in Acoustics 2pAAb1. Dah-You Maa, friend and scholar Leo Beranek* and Ning Xiang *Corresponding author's address: (no affiliation), 10 Longwood Drive, Westwood, MA 02090, beranekleo@ieee.org Maa, Dah-You's life as a scholar and a close friend of many both in China and North America is the theme. A number of his scholarly achievements starting from his time at Harvard University to the post-cultural Revolution period, and up to recent years, is reviewed. After receiving his doctorate in 1940 he began his life in Kunming, China where during the war with Japan he was a professor in the E.E. Department of the National S.-W. Associated University. He returned to Beijing in 1946 where he became the first Dean of Engineering in the National Peking University (now Beijing University). During the Cultural Revolution, 1966-1976, he was under house arrest. His sponsorship of the first All-China Acoustics Conference after the Cultural Revolution in 1979 heralded his position as China's leading acoustician. Excerpts from his many letters to Beranek through the years occupy most this presentation. Published by the Acoustical Society of America through the American Institute of Physics 2013 Acoustical Society of America [DOI: 10.1121/1.4799411] Received 7 Jan 2013; published 2 Jun 2013 Proceedings of Meetings on Acoustics, Vol. 19, 015059 (2013) Page 1
I. Introduction Figure1.ProfessorFredrickV. Hunt,DahYouMaa,Robert WallaceandLeoL.Beranekat HarvardUniversity,Cambridge, MAin1939. In1939DahYouMaabecameagraduatestudentintheSchoolofArtsandSciencesat HarvardUniversity.There,attheCruftLaboratory,MaaandBeranekoccupiedsidebyside researchroomsandtheybecameclosefriends.theyworkedwithprofessorfrederick.v. Huntonaproject(seePhotoinFig.1)thatresultedinapaperwiththethreeascoauthors titled, Analysisofsounddecayinrectangularrooms. 1 Thetworeceivedtheirdoctorates thesamedayinjune1940(seephotoinfig.2).maareturnedtochinaandthefollowing areexcerptsfromcorrespondencewithberanekfrom1940torecently.[notincludedinthe excerptsaretheusualgreetingsandexchangesaboutchildren,theweather,etc.] Figure2.DahYouMaaandLeoL. Beranekobtainedtheir Doctoratesonthesamedayin June1940atHarvardUniversity, theiradvisorwasprofessor FredrickV.Hunt. II. ProfessoratDepartmentofElectricalEngineeringatNationalSouth WestAssociatedUniversityinKunming,China September23,1940:MytripfromSanFranciscotoKunmingtookalmost40days,passing throughhongkongandhaiphong[theninfrenchindochina,nowinnorthernvietnam]. Everywherethebaggagewentwithme.BecauseoftheheavybooksIhave,Ipaidbaggagefees morethentwotimesofmypassage.mymotherandtwosistersarehere.attheuniversityiam givingacourseininelectricityandmagnetism.iamtryingtodosomeworkbesidesmy Proceedings of Meetings on Acoustics, Vol. 19, 015059 (2013) Page 2
teaching,buttherearemanytroubles.ifthejapscompletetheoccupationoffrenchindochina theywillbeonly400kmfromourcity.sowearepreparingforanothermigration.the transportationof1000tonsofbooksandequipmentand5000teachersandstudentsisnotan easyproblem.ifweloseourmostvaluablethingsheavenknowshowwecangetanymore. May14,1941:Howareyoudoingwiththe FourBooks [Maasentthiscompilationof ConfuciusquotestoBeranek,withthenote, Nowyouknow WhatConfuciussay. ]Ofcourse, theremightbethingsthatyoucan tagreewithhim.afterallhelived2600yearsago,youcan t expecthimtohaveallthemodernideas.hisideasabouthumanrelations,ithink,isaheadof thetimeevenin18 th centuryeurope May26,1941:The fluttering paper a hasonlybeenfinishedandi menclosingitforyour advice.theairraidhereisgettingbetternow.twoweeksagotherewerebombsagaininour vicinity,thenearestbombholeisonlyaboutahundredfeetfromourplacebutwedidn tsuffer anydamageatall.sincetherainyseasonisalreadyhere,weexpectstilllessraidsinthecoming threemonths.fromtheexperienceofthelastfewraids,itisn tsosafeevenatsomedistance fromthecity;mostlytheybombedthesuburbs.theonlytroublewithmeisthatican tdo muchworkonacousticsanditishardtokeepinformedabouttherecentdevelopments. June6,1941:Youprobablyhavereceivedmylastletterincludingamanuscriptonfluttering.In casethepaperispublished 2,IwonderifImaytroubleyoutoreadtheproofsbecausetosend theproofsheetsacrossthepacificiscostlybothintermsoftimeandintermsofmoney. Recentlywegotafundofalittlemorethanamillionc.n.(ChineseNational)dollarsforbooksof whichourdepartmentgets$600inu.s.currency.sowehaveorderedsomereferencebooks, allneedyones,afewonacoustics.besidesthiswegetaroundfifteenhundredc.n.dollars whichwecanspendfornewbooks. June15,1941:Theconditionshereseemmuchbetterthaninthepast.Sincetherecoveryof NanningandLungehowofKwangsiprovince,thethreateningoftheJapsonthispartofthe countryhasbeenmuchlessened.theonlywaytheycanattackusisbywayofannum,orthe FrenchIndoChina,buttheycan texpectanysuccessacrossthreehundredmilesof mountainouscountrywithwellpreparedfortifications.ontheseaccounts,wehavepostponed ourthirdmigrationforthetimebeing.rightnowweenjoyafewairraidseverymonth.how oftendoyouhavechinesemeals?iamenjoyingthemeverydayandsometimesigethungry foramericandishes;wehaveafewrestaurantshere,wheneverihavefivedollarstospareigo toafineoneandenjoyitmorethanididbackinthestates,iwonderwhy.ihopetheterrible thingwillbeoversoon.iwillbeverymuchpleasedtohavethehonorofbeinghostduringyour triptomycountry.iwillshoweverythingtoyouandyoumayseethattheaveragepeopleare muchnicerthaniam.touseachinesephraseforclosing, mypaperisshort,butmythinking foryouislong. a ThemanuscriptofthementionedpaperwaslaterpublishedinRef.2. Proceedings of Meetings on Acoustics, Vol. 19, 015059 (2013) Page 3
September16,1941:IreceivedyourletterofJuly25onlytwodaysago,itishardlyimaginable thatthemailsaresoslow.itisquitepeacefulherethesefewdays.airraidsirenhasn t soundedforalmostamonthnow,onaccountoftherainyseasonhere.theannualmeetingof thechinesephysicalsocietywasheldinthiscitylastweekend.duetotransportationtroubles, onlyabout50attended,nearlyallfromlocalinstitutions.about30paperswerepresentedinall branchesofphysics.idiscussedsomeofmyrecentworkon Mandarin (theordereddialectof China),itspropertiesfromaphysicist spointofview.ifoundthattheordinarychineseuseshis tonguetipinspeaking(toproducethesocalled dentalalvestarsound )morethanother parts.otherworkspresentedinthemeetingareaboutnuclearphysics,xrays,crystals,corona, Seismology,Hydrodynamics,etc. November14.1941:IgotaninvitationyesterdaytoyourweddingonthesixthofSeptember.I wanttoexpressmydeepregretsatnotbeingabletogettobostonattheduetime.according toourcustoms;iwishyouwilllivetogetherhappilyuntiloldwithwhitehairsonyourheads. July7,1944:Sogladtohearfromyouonthistrebleseventhday.Muchobligedforthetrouble thatmylastpaperinjasahascausedyou.i mafraidiwon tbeabletopaybackthemoney thatioweyouexceptafterthewar thatis,asyousay,ifthewareverhasanendwithinour lifetime.theinflationgetusreallybad,thelivingcostsareaboutonetenthofamegapercentas comparedto1937level,butwearebeingpaidat25timestheprewarsalaries.so,you llsee thefinancialconditionofus,butdon tstartworryingforus,theconditionsmight(ishouldsay withoutmuchdanger,isgoingto)getstillmuchworse,andwearereadyforit, asusual.but owingtomaterialandotherdifficultytheresearchworksarealwayslackinginschedule. PerhapsIlookforwardtoheartheexactnatureofyourresearchworksafterthewarisover. AndIamlookingwardalsotoyourvisittomycountry.IfIcangetafurlough,thatisafterthe war,iexpecttocomeandstaywithyouandprofessorhuntinordertocatchupwiththe progressyouhavemadeintheseyears,butiamnotsureifican,becausenobodyknowswhat thepostwarconditionsarelike. September19.1944:DelightedtoseeyourpictureinJASA,youlookfine.Ihaven tanypicture takenforsometime.i mashealthyasbeforebutgettingthinner.ihavelostalittlemorethan 20poundssinceIcameback.AlotofthingsthatIamnothappyaboutkeptmeworrying. PeoplesaythattheactualconditionsinChinaarebetterknownintheUSthanathome.Right nowitreallydoesn tlookveryencouraging,butiamsuresituationswillimprovebeforelong andwewillpullthrough.ihavewrittenapaperonfluctuationsofsoundduringdecay,lastyear, Ijustusedtheresultsofourjointpaperanddidalittlearithmetic.Theresultscomeoutrather simple.it sgoingtobepublishedinthechinesesciencerecordwhichisalreadymorethana halfayearinpressandmaybeoutinafewmonths.iwouldcertainlycomeandvisityouifican afterthewar,becauseiwanttolearntheworksyouhavedoneinthesefourorfiveyears. Chinaisnotthewayasitusedtobenowandthereisgoingtobemuchchangeinthefuture andihopethechangewillbeinthebetterdirection. October1,1945:Iwasn tabletowritesoonerbecauseihavebeenilloftyphus,whichisvery commoninthispartofthecountry.iamfullyrecoverednow.thesituationinchinaisreally Proceedings of Meetings on Acoustics, Vol. 19, 015059 (2013) Page 4
veryseriousbutnotsopessimisticasyouthinkinthestatesandistillthinkthatthe appeasementwiththesovietunionwilleasethesituationagooddeal.theassociated Universityisplanningtosplitintotheoriginalthreeandmovebackassoonaspossibleto PekinginsidethewalledcityandNankaiinTientsin,asbefore.Dependingonthetransportation conditions,themigrationwillstartsometimebetweennextdecemberandapril.hopethatwe won thavetoomuchtroubleinremovingthefivethousandpeopleandalltheequipment. Afterworkingfornearlysixyearsunderthepoorconditions,Iamthinkingofaskingtheschool forayearvacationwithpay.ifisucceediwillcomebacktoharvardnextfall.ican tsayforsure yetbecauseicannottellificansecureenoughforeignexchangetokeepmethereevenifiget thevacation.i llknowbetterbeforenextmay,ithink. [By1945mostChinesebelievedtheirgovernmenttobecorrupt.ThecommunistsunderMao TseTungfoughttheNationalists(government)underChiangKaiShekstartinginabout1945. Mao sforceshaddonemostofthefightingagainstthejapaneseduringtheoccupationandhe hadbroadsupportfromthepeasants.mao defeated Chiang s forces, and forced Chiang to flee to Taiwan in 1949.] December21.1945:Iamsendingyouacopyofmyfluctuationspaper b.thecopyofscience Reportnevercameout.ThiscopyisarevisedoneandIwonderifitcouldbeconsideredfor publicationintheacousticaljournal.wouldyougivemeyouradviceandpossiblehelp?ifit failstosatisfyyou,pleasedon thesitatetosayso.therehasbeensometroublerecentlyinthis city,thestudentsarestillinsistingonstrike.thelocalauthoritywastoblameforitsstartbutit isremotelyrelatedtotheconflictbetweenthekuomingtangandthecommunists.thetrouble maybeoversoon.merrychristmas. March25,1946:ReceivedyourletterofJanuarylast.Howisyourbookonacoustical measurementscoming?aboutthequestionsyouraisedaboutmyfluctuationpaper. 3 Ihave beenthinkingabouttherelativevaluesoftherandomnoise.ihavebeenthinkingaboutsome otherpossibilities.thepoliticalandindustrialsituationsinthiscountryarenotsatisfactoryat themoment.butiamstillasoptimisticasbeforeandbelievethatifweworkhardenough,a workablecomprise,asyoucallit,isnotwithoutreach. [ThemigrationoftheUniversity(andMaa)toPeking(Beijing)occurredintheFallof 1946.] b ThemanuscriptwaslaterpublishedinRef.3. Proceedings of Meetings on Acoustics, Vol. 19, 015059 (2013) Page 5
III. ProfessorinCollegeofEngineeringofNationalUniversityofPeking, Peking,China June14,1947.Asifyouhavethepowerofprophets,yourletterarrived3daysago,findingme sickinhospital.eversincewecamebacktopeiping[alternatewordforpeking]inlastfall,i continuallyhavetroubleswithmydigestivesystem.andthistimeparatyphoidofallthingsgot medown.duringthefirstdayortwo,onthe7 th,ihadafeverof104.4f.fortunately,itdidn t lastlongandihavepracticallyrecoverednow.thegreatmigrationofpeopleduringthewarled metosomestudiesofchinesedialects.thisarousedmyinterestinwaveanalysisandihave designedanallelectronicautomaticwaveanalyzer,butowingtomaterialdifficultiesihave neverbeenabletocompleteit.mostoftheaboveiwroteinchinese,butihaveashortarticle inenglishonwaveanalyzer(nottheautomaticoneijustmentioned)youmightbeinterested. Also,Ihaverewrittenmyfluctuationpaper 3 withsomeadditionsentirelyinchinese,somedayi willsendyouacopyandyoumightenjoylookingatit.iliketogetamoreorlessrigorous treatmentontheeffectofaudienceinaroom,buthaven tdonemuchyet.sincewemoveback topeipingihavebeenverybusyhelpingrestoretheschooltoitspeacetimeconditions.and besidesiamchargedwiththeresponsibilityofplanninganimprovedengineeringstudent trainingprogram,becausepeita(shortforthenationaluniversityofpeking)wasstartinganew engineeringcollegelastfall.ihavetostudyandtrytoproposeasuitablecurriculumforthis newcollegeandsomeadministrativeresponsibilitiesalsofallonmyshoulders.alltheseare consumingtoomuchofmytimeandiwanttogetawayfromitforsometimeatleastand quietlydoingmyworktohaveachancetodonothingbutresearch. June22,1948:Ihavebeenterriblytieddownthelastyearwithheavyteachingand administrativedutiesanditleftmewithverylittletimeformyownwork.iamtryingtohave myadministrativedutiesrelievedsoastohavemoretimetodoresearchwork.ifihavea chancetogoaway,itmaybeeasiertohavesomeoneelsetotakemyplace.however,evenif not,i lldomybesttotryanyway.amanlikemeisnotsuitableforadministration.weare ratherclosetowherethefightingisgoingonandonceinawhilewehavebeenentirelycutoff fromexternalcommunication(neverduringdaytime).butwearesafeenough,our35ftcity wallwillstandanyguerrillasiege.doyoustillrememberyourpromiseofvisitingusafterthe war.nowithasbeenoverforsometimeandanytimeyouarereadytocomeiwillarrangeitfor you.iguaranteeyouperfectsafety.howaboutitthiscomingfall?icouldofferyouavisiting professorshipifyoucouldstayforayear.coming? [BeranekrespondedthathewasbeginninghistenureatMITandtheyhadputnewcoursesin thecatalogwithhimasteacher.itwouldbeimpossibleforhimtogoduringtheacademic year instead,perhapsforasummer.thelastletterfrommaawasinjuly1948.] July17,1948.Wedon thavesummerschool.however,ihopethatyoucouldcomeforashort period.icouldarrangeforyoutobeatbothpekingandtsinghuauniversitiesforafewlectures. Proceedings of Meetings on Acoustics, Vol. 19, 015059 (2013) Page 6
ThepaywouldbejustenoughforspendingafewdaysinPeipingvisitingoldImperialBuildings, palacesandparks. [TheChinesePeople'sLiberationArmyformallyenteredBeijingonJanuary31,1949. On October 1st, 1949, MaoestablishedthePeople'sRepublicofChina, with Beijing as its capital. BeranekwroteletterstoMaaseveraltimesinthenexttwoyears.ThenafriendinFinland,who hadvisitedpekinguniversity,saidthatmaahadaskedhimtotellmethatlettersfromamerica weredangeroustohim.nomoreweresent.] [In1972PresidentRichardNixonvisitedChina.Accompanyinghim,amongothers,wasJordan BaruchwhohadbeenadoctoralstudentatMITunderBeranek.BaruchwasAssistantSecretary ofthedepartmentofcommerceandhevolunteeredtolookupmaa.beranekgavebaruch threebooksthathehadauthoredtopresenttomaa.maadidnotacknowledgereceipt.in 1979,ChinabecameopentovisitorsandBeranekwroteMaathathewouldbeamemberofa BostongroupthatwouldvisitseveralChinesecities,enteringApril17.] IV. HeadofInstituteofAcoustics,AcademiaSinica,Peking,China January16,1979:IsuggestthatyouproceedasyouhaveplanneduntilyourvisittoShanghai [Nanjing,Hangchow,Souchow,Yungchow,Quangchow,Guilin,Shanghai]andafterthatyou andmrs.beranekwillflybacktopekingandspend10moredaysinchina,asguestsofthe Academy.Here,inPeking,youwilldeliveryourlectures,holdaconferencewiththe acousticians,visitourinstitute,andotherplaces.youmayalsovisitothercities. Figure3.DahyouMaa s familywithmr.andmrs. BeranekinBeijing(1979). [MaaorganizedtheFirstAllChinaAcousticsConferenceheldaftertheCulturalRevolution. Beranekwasthekeynotespeaker,May7,1979,withapapertitled Noiseandvibrationcontrol ofairconditioningequipmentinbuildings. Aftereachsentence,translationwasmade.Maa nevermentionedhisweddingdate,buthefirstreferredtohiswife,wangronghe,infebruary Proceedings of Meetings on Acoustics, Vol. 19, 015059 (2013) Page 7
1980.InhislettersMaaoftenopenedwith, DearLeo,mybestfriend. Sometimesheopened, DearLeo,myelderbrother.Hewasfourmonthsyounger.(seePhotoinFigs.3.)] July9,1979:Inthelastfewweeks,itconvenedthePeople scongressandthepeople s ConsultativeCouncil,ofthelatterIamamember.Severallegalcodesthatyoumentionedin youraddresswerepassed.wewilltrytomakeitsothatthesituationsprevailinginthelastfew yearswillnotbeabletohappenagaininchina.wehaveyetalongwaytogobeforereallyget industrialized(wecallitmodernizationofagriculture,industry,defenseandscience),butlaw andorderwillhavetocomefirst.iassureyouagainthatyourvisithasgivenmuchhelpand pleasure. August291979:ThelecturesthatyougaveherewillappearintheNo.4ActaAcustica,in Chineseofcourse.Thereisnopublicationchargeandwewillpayforthetranslation.I llsend youthereprints.astheeditor[incnief],ithankyouforyoursupport. February4,1980:Yourbook Acoustics 4 isaveryimportantcontributiontotheeducationof futureacousticians.yourbooksaregoodreferencesforme.perhapsyouknowthatwehada Chinesetranslationandverysoonitwentoutofprint.Icouldn tfindacopylastyeartopresent toyou. [ManylettersoccurredbetweenBeranekandMaathroughtheyears.Excerptsfromafeware below.] July25,1981:IhavebeeninWarsawforasummerworkshoponacoustics.Itwasaninteresting meetingandimetsomeinterestingpeople.iwenttothecitycenteraswellastheoldcity.i wasshowntochopin shomeandsomeoldpalace.listenedtobach smusicinanoldchurch. WevisitedtheAppliedResearchInstituteandsomefactories.Whilethere,IwasinvitedbyPer BrueltovisitB&KandtheTechnicalUniversity. August30,1983:IwastoobusytowritealetterbecauseIhadtoprepareforthemeetingsof theinternoise83,the11 th ICAandtheISOTC43(Acoustics).ThenIflewtoEngland,firsthave afewdaysinsouthampton,theniattendedthemeetingsofinternoise83inedinburgh.in whichipresentedapaperonthemeasureofnonlinearimpedanceoforifice.andtheniflew toparisforthemeetingsofthe11 th ICA.IpresentedapaperonwordcountstatisticsinwhichI foundthatagenerallawexistsofthestatisticaldistributionofspeechwordsfordifferent languagesandsuggestedsomelinguisticfoundationforthis.thentheisotc43andwasback homeafternearlyamonth.andihavebeengivingasummercourseonspeechcommunication upuntilnow.ienjoyedallthisverymuch.imusttellyousomethingofmybook.itwasstarted intheculturalrevolutionwhenihadplentyoftime,butfinishedonlyrecently.thebookis HandbookofAcoustics.Theauthorsaremeandanotherman.Ithas23chapters. April10,1985:IwasverybusyinthelastthreemonthsinpreparingabookonSpeech InformationandCommunication,toprovidesomemodernviewofspeechprocessingespecially Proceedings of Meetings on Acoustics, Vol. 19, 015059 (2013) Page 8
aboutthechineselanguagetolinguistsandthecommunicationengineers.myideaisthat thingscanbedonebetterifthelinguistsknowmoreofthetechnicalsideandengineersknow moreaboutthespeech. V. ALeadingAcousticianfromlate1980 sandbeyond [BeranekandhiswifewenttoChinainSeptember1987(seePhotoinFig.4).Maaarranged withthechinesetravelagencyforthemtomakeatour,accompaniedbyagraduatestudentli Yimin.TheyvisitedBeijing,Xian,Chengdu,KunmingandLhasa.] August7,1991:IntheseyearsIhavegivenupmyadministrativedutiesandIhavebetter conditionstoworkandihavetoworkbetter,becauseihavelostsomuchtimebefore.tome, ithasbeen Lifebeginsatsixty, myscientificlife.iexpecttoworkafewyearsmore.inowtake threegraduatestudents,twoofthemareonthethesisstage.theyallworkveryhardaswedid somehalfcenturyearlier. [Beranekattendedthe14 th ICAConferenceSept.4 th to6 th 1992inBeijing.] October8,1992:I mespeciallygladtoseeandhaveatalkwithyou.yoursupportfortheicais greatlyappreciated.itseemsitisadvisableforyoutorefrainfromtoomuchactivityandtotake bettercareofyourhealth.andanotherthingistobeoptimisticoneverything. Figure4.(Left)DahYouMaaandLeoL.BeranekinMaa shomeoffice(beijing,1987). (Right)DahYouMaaandLeoL.BeranekinBeijingafterlecturesinNanjing(2002). [BeranekwasaguestlecturerinNanjingUniversity,May19 th to24 th,2002.then BeranekwenttoBeijingforthreedaysafterwards.ThatwasthelasttimeMaaand Beranekweretogether.] Proceedings of Meetings on Acoustics, Vol. 19, 015059 (2013) Page 9
VI. Coda 5 DahYouMaabecameincreasinglyinvolvedinmanyscholarlyactivitiesandadministrativeroles in Chinese and international acoustics community. DahYou Maa was one of the founding membersofthetechnicalcommitteeonacousticsinthechinesesocietyofphysics,laterto become the Acoustical Society of China (ASC), where he served as president (198285) and honorary president (1985). He was also Chairman of the Chinese National Standard on Acoustics and has been the EditorinChief of both ACTA ACUSTICA (in Chinese) since its inceptionin1964andthechinesejournalofacoustics(inenglish)since1984. Throughout his academic career DahYou Maa has authored and coauthored more than 20 books.oneofhislatestbooks,"thefoundationofmodernacoustictheory"publishedin2004, systematically reflects his deeper understanding of acoustics theory through his own contributions, and discusses new developments of acoustic technology. This book, published whendr.maawas88yearsofage,iswidelyusedasatextormainreferencebookinmany universitiesinchina. Maa accomplished remarkable work throughout his career, 5 many invited papers in this memorial session will brief many of his contributions. The coauthor (N.X.) of this paper has personallyexperiencedthetimeperiodwhenthemicroperforationtheorywasappliedinone notableproject;transparentmicroperforatedabsorberswereusedinthegermanparliament Hall in Bonn in 1993, efficiently solving the existing architectural acoustic problems. The Fraunhofer Society of Germany awarded him the Gold Medal in 1997 and the Fraunhofer Institute of Building Physics in Stuttgart awarded him prestigious ALFA Award in June 1997. Duringtheawardceremony,thecoauthor(N.X.)hadthegreathonortobeassignedbythe instituteheadtotranslatehisspeechintogerman.[hisspeechwasgiveninchinese;n.xiang translatedsentencebysentenceinfrontoftheaudience.hesaidsomethinglikethis talking aboutscientificcontributions,ididn tdoanythingspecial.iwasjustlikeasmallboywalkingon apeacefulbeach,tryingtopickupsomenicestones.indeedifoundafewofthem,someare colorful,looknice,afewlookreallypretty ] Figure5.Inhisofficeatthe InstituteofAcoustics,Chinese AcademyofSciences,Dahyou Maawelcomedagroupof graduatestudentsofgraduate PrograminArchitectural Acoustics,Rensselaer PolytechnicInstitute(2007). Proceedings of Meetings on Acoustics, Vol. 19, 015059 (2013) Page 10
DuetothefriendshipofthecurrentauthorswithDahyouMaa,eventhegraduate/Ph.D. studentsofthegraduateprograminarchitecturalacoustics,rensselaerpolytechnicinstitute (RPI)havebeenbenefited:insummer2007,agroupofgraduatestudentsledbyN.Xiang.from RPIhadagreathonortobewelcomedbyProf.MaainhisofficeinBeijing(seeFig.5). Reference 1 HuntF.V.,Beranek,L.L.andMaa,D.Y.,Analysisofsounddecayinrectangularrooms,J.Acoust.Soc.Am.11 (1939),8094. 2 Maa,D.Y.,Theflutterechoes,J.Acoust.Soc.Am.13(1941),170178. 3 Maa,D.Y.,Fluctuationphenomenainroomacoustics,J.Acoust.Soc.Am.18(1946),134139. 4 Beranek,L.L.Acoustics,1954,(McGrawHill,NewYork) 5 Xiang,N.,Beranek,L.L.andWang,J.Q.,EncomiumoftheHonoraryFellowshipAwardbytheAcousticalSocietyof America,J.Acoust.Soc.Am.131(2012),34093412. Proceedings of Meetings on Acoustics, Vol. 19, 015059 (2013) Page 11