材料科學(xué)專(zhuān)業(yè)英語(yǔ)詞匯（D）

材料科學(xué)專(zhuān)業(yè)英語(yǔ)詞匯(D)d-nickeld鎳(含4-5%mn之鎳合金)dacite石英安山石dacronpolyesterfibers達(dá)克隆聚脂纖維daetwyler-schiltknechtabrasionmachine戴許磨耗機(jī)dairybronze奶罐青銅(20%ni,8%zn,4%sn,其余為cu)dairyproducts乳酪產(chǎn)品dambar堵住桿，緯damblock水閘方塊damageline[疲勞]損害比例damageratio達(dá)馬新法(熔接高低碳鋼而形成多層材料裝飾品之一種方法)damascene金屬鑲嵌法damascening大馬森合金(含10%sn之青銅)damaxinealloy制振能dammar達(dá)瑪脂dammargum達(dá)瑪膠dampproofingandpermeabilityreducingagent防水劑damper風(fēng)門(mén)dampingcapacitydampingtest制振族驗(yàn)dancerroller上下跳動(dòng)滾輪dandelionmetal登德耐易金屬(含18%sb,10%sn,

其余為pb之軸承合金)dapple不勻darcy'slaw達(dá)西定律darkcondition黑暗條件darkfield暗視野darkfieldmicroscopy暗場(chǎng)顯微法dart-droptesting雙軸彎曲試驗(yàn)darwin'sconcept達(dá)爾文觀念dashetching達(dá)斯蝕刻dash'sneck達(dá)斯（縮細(xì)）頸部dashpots緩沖筒datainterpretation數(shù)據(jù)闡明datalevelsource數(shù)據(jù)位階電源dataloggingmemory資料記錄記憶器datalogging/datalog數(shù)據(jù)記錄/數(shù)據(jù)記錄表datamemory數(shù)據(jù)記憶器datascramblefunction數(shù)據(jù)打散功能datatopologicalfunction數(shù)據(jù)拓?fù)涔δ躣atolite矽鈣硼石daubing[耐火砂]自補(bǔ)，涂抹daytank日量熔槽daylight凈距(壓機(jī))daylightfastness色耐陽(yáng)光度dcdiodesputteringsystem直流二極管濺鍍系統(tǒng)dcmeasurement直流測(cè)量單元dcparametertestsystem直流參數(shù)測(cè)試系統(tǒng)dcparametrictest/dctestdc參數(shù)試驗(yàn)/直流測(cè)試dctest直流測(cè)試debroglielaw德波格里定律(現(xiàn)代電子繞射技術(shù)基礎(chǔ))de-airing除氣法de-aluminification脫鋁作用(鋁青銅)de-emulsification解乳化de-enamelling去琺瑯de-lavauedprocess德拉瓦[離心鑄管]法de-skew相位或時(shí)間偏差之補(bǔ)償deacetylatedchitin去乙醯賣(mài)質(zhì)deactivation反活性化deactivators去活化劑deadclay僵土deadplate靜板deadsoftcastiron極軟鑄鐵deadsoftsteel極軟鋼deadspots僻區(qū)deadweighttype/naturalweighttype凈重式dead-burned僵燒dead-burneddolomite全燒白云石dead-burnedmagnesite全燒鎂石dead-endpolymerization終端聚合deaeration脫氣deags脫氣debiteuse浮標(biāo)磚debranchingenzymes脫支梅debugger除錯(cuò)程式deburring去滿(mǎn)邊debyecharacteristictemperature戴比特性溫度debyecircles狄拜圈debyeequation狄拜等式debye'sconcept狄拜觀念debye-huckelapproximation狄胡近似法debye-huckeltheory狄胡理論debye-scherrercamera戴薛氏照相機(jī)debye-scherrerdiagrams狄拜圖譜decaborane十硼十四氫decaboranepolymers十硼十四氫聚體decal印花decalcomania印花decalescence減輝decalescencepoint減輝點(diǎn)decanedioicacid癸二酸decanning去套管decanoicacid癸酸decarboxylation去羧基作用decarburization脫碳decarburizeddepth脫碳深度decarburizedlayer脫碳層decarburizedstructure脫碳組織decay袞變decaytime袞變時(shí)間decelerationmode減速模式dechlorinationequipment除氯設(shè)備decibel分貝decoloration消色decolorizer1

去色劑2脫色劑decomposition分解decompressionsection去壓部位decorpaper裝飾紙decorsheet裝飾板decorating裝飾decoratingkiln紅爐；彩燒窯decorativecoating裝飾護(hù)膜decorativeconcrete裝飾混凝土decorativeeffects裝飾效應(yīng)decorativelaminates裝飾層板decorativeribbon裝飾帶條decoring砂心清除decorvtivebackcoat回布裝飾decylacrylate丙烯酸癸酯decylalcohol

(1-decanol)癸醇deepeltch深蝕deepforming深成形deephardeningsteel深硬化鋼deeplevel深能階deepleveltransientspectroscopy深能階暫態(tài)光譜學(xué)deepsubmicrondesign深態(tài)次微米設(shè)計(jì)deep-drawingsteel深沖[用]鋼deep-submergencesystem深浸系統(tǒng)deep-submergencevehicles深浸媒體deerskins廘皮dee[-pilefabrics長(zhǎng)毛織物defasher塑模溢料殘?jiān)コb置defect瑕疵，缺陷defectlattice缺陷格子defectsemiconductor瑕疵半導(dǎo)體defectstructure缺陷組織defects缺點(diǎn)deflagration爆燃(燃燒)deflashing去毛邊deflocculant反凝劑deflocculants反凝劑deflocculation反凝defoamingagents去泡劑deformability變形度deformableparticles可變形粒子deformation變形deformationband變形帶deformationeutectic變形共熔物deformationmechanisms變形歷程deformationproperties變形性質(zhì)deformationrate變形率deformationstructure變形組織deformationtemperature變形溫度deformationtexture變形織構(gòu)deformationtwin變形雙晶deformationvelocity變形速度deformationwidthofwire變形線(xiàn)寬deformation,reversible可逆變形deformation-stressdependencies隨應(yīng)力變形deformation-timedependencies隨時(shí)間變形deformations,infinitesimal極微變形deformedballdiameter變形球徑defroster除霜器，防結(jié)冰裝置degadation敗壞，降級(jí)degasification脫氣degassing放氣degassingflux脫氣熔劑degassingrate去氣率degating去澆口degaussing去磁degermination去芽deghdrogenation脫氫degradation退解degradationofplastics塑膠退解degradationofstyrenepolymers苯乙烯聚合物退解degradation,latent潛伏退解degradativeprocesses退解過(guò)程degreaser去油劑degreeofbranching分支度degreeofcrosslinking交連度degreeofcrystallinity結(jié)晶度degreeofcure硬化度degreeofdegradation退解度degreeoffatique疲勞程度degreeoffreedom自由度degreeofhydration水合度degreeofisomerization異構(gòu)度degreeofisotacticity整排度degreeoforientation定向度degreeofpolymerization聚合度degreeofsaturation飽和度degreeofsubstitution取代度degydration脫水dehardening減硬dehydration脫水dehydrationbake脫水烘烤dehydrochlorination脫氯化氫dehydrogenatedrosin脫氫松香dehydrogenation脫氫dehydrogenationprocesses脫氫法deionization去離子作用deionizedwatercooling去離子水冷卻deirondemanganeseequipment除鐵除錳裝置delaymodel延遲模型delaytime延遲時(shí)間delayedelasticity延遲彈性delayedfracture延遲破斷delayedqueching延遲火delayedtransformation延遲變態(tài)delayedyield延遲降伏delayed-tackadhesives遲固黏著劑deleterioussubstance有害物質(zhì)delftware德弗特陶器dellusterauts褪光劑deltabrassδ黃銅deltabronzeδ青銅deltaironδ鐵deltametalδ合金deltasolidsolutionδ固溶體delustering褪光demagnetizer去磁器demagnetizingcurve消磁曲線(xiàn)，去磁曲線(xiàn)demountingmachine/demountstation晶圓卸裝機(jī)denaturation變性dendrite樹(shù)枝狀結(jié)晶；樹(shù)狀突dendriticpowder樹(shù)枝狀粉未dendriticsegregation樹(shù)枝狀偏析dendriticspherulites,fibrous纖維狀椏球dendriticstructure樹(shù)枝狀組織denier丹尼值denitriding脫氮dense1

致密(陶)2高折射率(玻)denseflint重火石玻璃densener冷鐵densificatiokn壓緊density密度densitycrystallinity密度結(jié)晶densitydefect密度缺點(diǎn)densitymeasurements密度測(cè)量densitymethod密度法densityratio密度比density-gradientcolumn密度坡柱density-gradientsedimentation密度坡沈積density-theoritical理論密度dentalgold牙科用金(含5-12%ag,4-10%cu,

其余為au之合金)dentalporcelain牙用瓷denudedzone無(wú)缺陷領(lǐng)域deoxidation

(deoxidization)脫氧，去氧deoxidizedcopper脫氧銅deoxidizer脫氧劑deoxidizing去氧，脫氧deoxidizingagent脫氧劑deoxigenation脫氧dependenceoflifetimeoncurrentdensityplot壽命與電流密度之依存性關(guān)系圖dependenceoflifetimeontemperatureplot壽命與溫度之依存關(guān)系圖dephosphorization脫磷depleteduranium耗竭鈾，耗乏鈾depolarization去極化作用depolarizer去極化劑depositeattack沈積侵蝕depositeprotection沉積防蝕deposition沉積depositionchamber沉積室，蒸鍍室depositionrate蒸鍍速率depresseddiepad下凹晶片焊墊depthofchill冷硬深度depthoffocus聚焦深度derby[金屬]圓餅(特指鈾金屬餅又名biscuit)descale去銹designautomationconference自動(dòng)設(shè)計(jì)學(xué)術(shù)研討會(huì)designautomation（da）設(shè)計(jì)自動(dòng)化designfortestability可測(cè)試性程式designkit設(shè)計(jì)套組designrulecheck設(shè)計(jì)法則查驗(yàn)desilverizing去銀destructivetesting破壞性試驗(yàn)desulphurization脫硫devalabrasiontest戴佛磨損試驗(yàn)developer顯影機(jī)developertemperaturecontrol顯影液溫度控制developingrate顯影速率developinguniformity顯影均質(zhì)性developmentenvironment研發(fā)環(huán)境device裝置，元件devicemodel裝置模型，元件模型deviceprogram裝置程式devicesimulator裝置模擬器deviceundertest被測(cè)試裝置devitrification失透；反?；痙evitrifiedglass失透玻璃devitrite失透物dewpoint露點(diǎn)dewaxing脫蠟dewpointindicator露點(diǎn)計(jì)dextrin糊精dezincification脫鋅dhdegassingprocessdh去氣法dhpcopperdhp銅sofgdi-vacancies雙空位dialysis透析；滲析diamagneticsubstance反磁性體diamagnetism反磁性diamond金剛鉆，鉆石diamondcubic鉆石立方diamondcvd金鋼鉆cvddiamondelectrodepositionwire電解金鋼砂沉積線(xiàn)diamondlattice鉆石[型]格子diamondpolishing鉆石[細(xì)粉]拋光diamondpyramidhardnessdphdiamondpyramidhardnesstest鉆石[角]diamondstructure金鋼石鋸diamondwaw錐硬度試驗(yàn)diamondwheel金剛石磨輪diaphrampump隔膜泵diaspore水鋁石diatomaceousearth鉆石[型]組織diatomitediatomaceousearthdiatomitefilter珪藻土過(guò)濾器diccavity型腔，模槽dicalciumsilicate矽酸二鈣dichromatetreatment金普(pr,59),金女(nd,60)之通稱(chēng)dicing切割dicingsawnetworkmanagement切割鋸刀網(wǎng)路管理dicingsaw/dicer切割鋸刀/切割機(jī)dickite二重高嶺土didymium麥藻土die模diealignment晶片調(diào)準(zhǔn)dieblock模diebonding晶片接合，晶片焊接diebottom模塊diecast鑄模diecastalloy壓鑄diecasting壓鑄合金diecastingmachine壓鑄法diecavity晶片固定腔dieclearance壓鑄機(jī)diecushion模墊(壓機(jī))diedroppingrate晶片掉落率dieelectric電介質(zhì)，電介體dieforging模鍛dieimpression模型dieinsert模嵌塊dielayout模布置dielife模壽命dielock模鎖dielubricant模具潤(rùn)滑劑diemaking制模diemismatch模錯(cuò)位dieobnder晶片接合機(jī)dieopening模距diepad/island晶片焊墊/孤島dieplate印刷版，鉛版diepressquenchiong模壓卒火diepressing模壓dieproof驗(yàn)?zāi)＜iequench夾模卒火dieseat模底dieset模組diesetting裝模dieshank模柄dieshearstrength晶片抗切強(qiáng)度diesheartester晶片切變強(qiáng)度測(cè)試機(jī)dieshift模移量dieshoe模托(壓機(jī))diesinking刻模diesinkingmachine刻模機(jī)dieslide模滑條(壓機(jī))diesorter晶片分選機(jī)diespace模面大小diesteel模用鋼dietemperature模溫dietray晶片托盤(pán)dieupper上模die,cast下模die,composite組合模die,compound復(fù)序模die,conterlocked對(duì)鎖模die,continental樣板模die,drop-through下穿模die,finishing完成模die,flat平模die,floating浮動(dòng)模die,gripper夾持模die,inserted嵌型模die,inverted倒置模die,lower下模die,moving動(dòng)模die,multiple多件模die,multiplecavity多內(nèi)模die,multiple-impression多型模die,multiple-part多件模die,plate樣板模die,progressive順序模die,push-through穿通模die,return返回模die,roll滾筒模die,single-covity單內(nèi)模die,single-impression單型模die,single-operation單序模die,sizing擠準(zhǔn)模die,slidikng滑動(dòng)模die,solid整體模die,split分開(kāi)模die,stationary定模die,steel-rule鋼條模die,subpress模架模die,swage型鍛模die,template樣板模die,top上模die,transfer自送連制模die,trimming自邊模die-by-diealignment晶片間對(duì)準(zhǔn)die-by-dieleveling晶片間調(diào)平die-by-dietilting晶片間傾斜轉(zhuǎn)動(dòng)dielectric介電dielectricconstant介電常數(shù)dielectricinsulator介電絕緣體dielectricstrength介電強(qiáng)度differentialaerationcorrosion氧差腐蝕differentialdcmeasurement差動(dòng)直流測(cè)試differentialdilationcurve示差膨脹曲線(xiàn)differentialgear差速齒輪differentialheating差別加熱differentialmicrometer差動(dòng)分厘卡differentialpressuregauge差壓計(jì)differentialquenching示差卒火differentialthermalanalysis示差熱分析differentialthermocouple示差熱電偶differentialthermogravimetry示差熱重量法diffraction繞射diffraction

(x-ray)繞射線(xiàn)（x射線(xiàn)）diffractometer繞射儀diffusedwafer經(jīng)擴(kuò)散晶圓diffusion擴(kuò)散diffusionactivationenergy擴(kuò)散活化能diffusionannealing擴(kuò)散退火diffusionbonding擴(kuò)散接合diffusionboundarylaver擴(kuò)散境界層diffusioncoating擴(kuò)散護(hù)膜diffusioncoefficient擴(kuò)散系數(shù)diffusioncoefficient

(d)擴(kuò)散系數(shù)diffusionconstant擴(kuò)散常數(shù)diffusionhardening擴(kuò)散硬化diffusionhole擴(kuò)散孔diffusioninternalfriction擴(kuò)散內(nèi)耗diffusionnormalizing擴(kuò)散正常化diffusionprocess擴(kuò)散法diffusionpump擴(kuò)散幫浦diffusionsintering擴(kuò)散燒結(jié)diffusiontransformation擴(kuò)散變態(tài)diffusionzone擴(kuò)散帶diffusion-controlledprecipitation擴(kuò)散控制沉diffusion-controlledtransformation擴(kuò)散控制變態(tài)(轉(zhuǎn)換)diffusionlesstransformation無(wú)擴(kuò)散變態(tài)diffusivity1擴(kuò)散性2擴(kuò)散率digital(controlbonding)head數(shù)位控制壓接頭dilatationcurve膨脹曲線(xiàn)dilatometer熱膨脹儀dimension1尺寸2因次3維，度dimensionchange尺寸變化dimensionalinstability尺寸不穩(wěn)定性dimensionalstability尺寸安定性dimensionaltolerance尺寸公差dimethylglyoximetest定性試驗(yàn)dimmingtest耐朦試驗(yàn)dimple凹坑，表面微凹din

(deutscheindustrienormen)德國(guó)工業(yè)標(biāo)準(zhǔn)dinasbrick矽磚dings-crockettseparator丁一式分離機(jī)diodeparallelplateplasmaenhancedcvdsystem二極管平行板等離子增強(qiáng)型cvd系統(tǒng)diodesputteringsystem二極管濺系統(tǒng)diopside透輝石diorite閃長(zhǎng)巖dipbrazing熱浸硬焊dipdeveloper浸漬式顯影機(jī)diptransfer浸送(熔接時(shí)金屬由電極至熔池)dipcoat浸涂，浸覆dipole偶極，雙極dipolematerials偶極性材料dipping浸漬directarcfurnace直接電弧爐directarcheating直接電弧加熱directchillcasting直接冷鑄directdisplacementtypecleaningequipment直接置換式洗滌裝置directextrusion順擠，直接擠制directfiring1直接噴燃(泥)2敞燒法(陶)directheatmethod直接加熱法directindexfunction直接索引功能directinterchangediffusion直接交換擴(kuò)散directpickup直接拾取directquenchaging直接卒火時(shí)效directredrawing順向再拉延directreductionprocess直接還原法directstress正交應(yīng)力directteemingtoppouringdirecttempering直接回火directtransformation直接變態(tài)directwriting直接描畫(huà)direct-arcfurnace直熱電弧爐directionalproperties方向性directionalsolidification方向性凝固directionality方向性dirt渣dirtinclusion夾灰dirttrap集灰阱disappearingfilamentpyrometer隱絲[光學(xué)]高溫計(jì)disappearing-filamentpyrometer隱絲光測(cè)高溫計(jì)discaloy迪卡洛(耐熱鋼之一種)discard去錠頭discontinuouseutectic不連續(xù)共晶discontinuousprecipitaion不連續(xù)析出discontinuousdiscontinuousyielding不規(guī)則降伏discretecomponenttestsystem離散元件測(cè)試系統(tǒng)dishing凹狀扭曲研磨dishingpress碟壓機(jī)disintegration崩解disintegrationindex散解指數(shù)disintegrator散解機(jī)diskfeeder盤(pán)飼機(jī)dislocation差排dislocationclimb差排爬登dislocationdensity差排密度dislocationfreecrystal無(wú)位錯(cuò)結(jié)晶dislocationline差排線(xiàn)dislocationlocking差排楔梢dislocationstrength差排強(qiáng)度disorderedsolidsolution無(wú)規(guī)律固溶體disordering非規(guī)律化dispenser配料機(jī)，點(diǎn)膠機(jī)dispensernozzle配料機(jī)噴嘴disperingagent播散劑dispersedshrinkage分散縮孔(鑄疵)dispersion播散dispersioneffect播散效應(yīng)dispersionhardening播散硬化dispersionstrengthening播散強(qiáng)化dispersiontypefuel分散型[核子]燃料dispersoid散播物displacementenergy移位能displacementspike原子移位區(qū)disposablecarbidetip棄換式碳化物刀尖塊disruptivestrength破裂強(qiáng)度dissimilarmetalcorrosion異極[金屬]腐蝕dissociationpressure解離壓力distancehardness端距硬度distillate餾出物distilledwater蒸餾水distortion歪變，畸變distributedprocessing分散式處理distributioncoefficient分配系數(shù)divermethod潛取[樣]法divergentlens發(fā)散透鏡divisionwall隔墻divorcedcementite分離雪明碳鐵divorcedpearlite粒狀波來(lái)鐵dns碳金目鋼dobbin轉(zhuǎn)盤(pán)乾燥器doctorblade刮刀片documentglass文件玻璃doghouse進(jìn)料口；浮標(biāo)磚入口doloma白云石灰dolomite白云石dolomitebrick白云石磚domain域domainwall磁[區(qū)]壁dome窺窿(圓題室)domebrick圓頂磚domejig圓頂夾具domeplug爐頂塞磚donorannihilation消除氧氣施體donorimpurity施素不純物donorkiller氧氣施體殺手donorlevel授素準(zhǔn)位dopant摻雜劑doping摻雜dopingdefect摻缺缺陷dopingsystem摻雜系統(tǒng)doppelduroprocess杜氏火焰硬化法dorebullion多爾錠(金銀錠)doremetal多爾金屬(金銀合金)doresilver多爾銀(含少量金)dorragitator杜爾攪動(dòng)器dorrmill道爾磨機(jī)dorrthickener杜爾濃稠槽dorrcofilter杜柯過(guò)濾機(jī)dose劑量dotlogging點(diǎn)紀(jì)錄dotwelding點(diǎn)熔接doubleannealing雙重退火doublecarbide復(fù)碳化物doublecontraction雙重收縮doublecruciblemethod雙重坩堝法doubledraining再排漿(搪瓷)doubleequilibriumstate復(fù)平衡狀態(tài)doubleextradeuseflint雙超重火石玻璃doublenormalizing霸重正?；痙oubleorientedsiliconironsheet雙向性矽鋼片doublepasspreheater雙程預(yù)熱器doublequenching雙重卒火doublesidelappingmachine雙面磨光機(jī)doublesidepolishingmachine雙面拋光機(jī)doublesidedaligner基板上下兩面對(duì)準(zhǔn)曝光器doubleskin夾層(鍛鑄件外層瑕疵)doubletelecentriclens雙重遠(yuǎn)心透鏡doubletetrahedralunit雙四面體單元doublethermochemicaltreatment雙重?zé)峄Ｌ幚韉ouble-archhammer雙拱鎚double-endupsetforging雙端鍛粗double-endupsets雙端鍛粗件double-endupsetting雙端鍛粗法double-faceware雙面搪瓷器double-framehammer雙架鎚double-fritglaze雙玻料釉double-stagenitriding雙重氮化法dowmetal陶氏金屬(一種鎂合金)dowprocess陶氏法dowel1合釘，定位銷(xiāo)2雙尖釘downandupcut同方向及逆方向交互切割，反覆切割downcutting下行切割downflowasher/downstreamasher下游灰化機(jī)downhandwelding水平焊接downset下移安置downsizing小型化downsprue下澆道downstreamplasmaetchingsystem分離型等離子體蝕刻系統(tǒng)down-draughtkiln倒焰窯down-drawprocess下拉法(玻)dph

(diamondpyramidhardness)dph硬度(同維氏硬度)draft1拔模斜度2繪圖3通風(fēng)，通氣4吃水(船)drag落砂（鑄疵）dragflask下砂箱drag-ladledragadedrag-line拖索挖掘機(jī)dragline拖索drainbox廢液回收箱draincastinghollowcastingdraintile排水瓦管(從土木)drawbar拉引棒磚drawbend抽絲珠drawbending拉延曲面drawring拉延環(huán)drawability拉延性，可拉性drawebench拉制機(jī)臺(tái)drawing1回火2拉制，抽制3繪圖drawingchamber拉引間drawingdeep深拉延，深度引長(zhǎng)drawingdie拉模drawingwet濕拉延drawing,dry乾拉延drawing,shallow淺拉延dressing修整dressingcarriers/conditioningcarriers修整/條理用承載齒輪drift1沖銷(xiāo)2輕敲drifttest頂進(jìn)定量變形試驗(yàn)driophammerforming落鎚成形driver驅(qū)動(dòng)器driver/comparator驅(qū)動(dòng)比較器drop落砂(鑄疵)droparch低拱dropcutting下穿切割dropfeedcarburizing滴注滲碳dropforging落鎚鍛drophammer落鎚droptest1墜重試驗(yàn)2墜落試驗(yàn)drop-throughdie下穿模dross浮渣drude-lorentzlaw朱羅式定律(金屬高導(dǎo)電率)drummixer鼓形拌合機(jī)drybattery乾電池組drybody乾坯drycell乾電池drycleaningequipment乾式洗滌設(shè)備drycopper乾銅(含多量氧化亞銅之脆性銅)drycorrosion乾蝕drycyaniding乾式氰化法drydeveloping乾式顯影dryetchingsystem乾式蝕刻系統(tǒng)dryice乾冰drymixing乾混法drypan乾輾盤(pán)drypermeability乾砂通氣性drypowderhoningmachine乾式溢料殘?jiān)鼑娚扒宄龣C(jī)drypressing乾壓dryprocess乾式法dryprocessenameling乾法搪瓷dryquenching乾式卒火drysand乾沙drysandmolding乾模法dryshrinkage乾燥收縮dryspray乾噴drystrength乾強(qiáng)度(陶)drytempering乾式回火dryvacuum