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簡(jiǎn)介:JMATERSCI4120062195–2200SURFACECHEMICALANALYSISOFTENCELANDCOTTONTREATEDWITHAMONOCHLOROTRIAZINYLMCTΒCYCLODEXTRINDERIVATIVENKISTAMAH,CMCARR?TEXTILESANDPAPER,THEUNIVERSITYOFMANCHESTER,MANCHESTER,M601QD,UKEMAILNARAINDRAKISTAMAHMANCHESTERACUKEMAILCHRISCARRMANCHESTERACUKSROSUNEEDEPARTMENTOFTEXTILETECHNOLOGY,UNIVERSITYOFMAURITIUS,REDUIT,,MAURITIUSEMAILSROSUNEEUOMACMUPUBLISHEDONLINE3MARCH2006THEINTERACTIONANDDURABILITYTOLAUNDERINGOFAREACTIVEΒCYCLODEXTRINDERIVATIVE,APPLIEDTOTENCELFABRICANDBLEACHEDCOTTONFABRIC,WASINVESTIGATEDUSINGXRAYPHOTOELECTRONSPECTROSCOPYXPSTHEN1SXPSSPECTRAOFTHEMCTΒCYCLODEXTRINTREATEDSUBSTRATESREVEALEDTHEPRESENCEOFTHEAPPLIEDFINISHONTHEFIBRESURFACEANDTHATTHESURFACECONCENTRATIONINCREASEDWITHINCREASINGLEVELOFTHEAPPLIEDFINISHTHEBLEACHEDCOTTONHADARELATIVELYGREATERLEVELOFFIXATIONOFTHECHEMICALFINISHINCOMPARISONTOTHETREATEDTENCELTHEREACTIVEΒCYCLODEXTRINFIXEDONTOTENCELANDBLEACHEDCOTTONWASDURABLETOISOCO6/C2SWASHESC?2006SPRINGERSCIENCEBUSINESSMEDIA,INC1INTRODUCTIONCYCLODEXTRINSARECYCLICOLIGOSACCHARIDES,WITHTHEMAJORCYCLODEXTRINBEINGTHESEVENMEMBEREDRINGDERIVATIVEΒCYCLODEXTRINCYCLODEXTRINSAREBULKYRINGMOLECULES,CAPABLEOFFORMINGINCLUSIONCOMPLEXESWITHAGREATNUMBEROFORGANICCOMPOUNDSANDHAVEFOUNDWIDEAPPLICATIONSINMANYAREAS1–7INTEXTILES,CYCLODEXTRINSAREARELATIVELYNEWCLASSOFDYEINGANDFINISHINGAUXILIARIESCAPABLEOFINFLUENCINGBOTHTHEPROCESSINGOFTHETEXTILEMATERIALSANDTHEIRSERVICEABILITYPROPERTIES1,6–15CYCLODEXTRINSMAYBEBOUNDONTOTHEFIBRESURFACEBYTWODISTINCTINTERACTIONSAWHERENOCOVALENTBONDSEXISTSBETWEENTHECYCLODEXTRINMOLECULESANDTHETEXTILEMATERIAL,ANDPHYSICALBONDINGISTHEMAJORFORCEOFINTERACTIONBWHERETHECYCLODEXTRINMOLECULEISPERMANENTLYFIXEDTOTHETEXTILEMATERIALTHROUGHCOVALENTBONDINGDUETOTHEIRSTRUCTUREANDABILITYTOFORMINCLUSIONCOMPLEXESCYCLODEXTRINSHAVEBEENEVALUATEDWITHAVIEWTOEITHERSLOWLYRELEASINGPERFUMEORABSORBINGUNPLEASANTODOURSONTEXTILESOROTHERMATERIALS11THEYAREPOTENTIALLYUSEFULINDETERGENTSANDOTHERTEXTILECAREPRODUCTS,BUTDUETOTHEIRRELATIVELYWEAKADSORPTIONWOULDBELOST?AUTHORTOWHOMALLCORRESPONDENCESHOULDBEADDRESSEDDURINGGARMENTLAUNDERINGANDTHEREFORETHEIREFFECTSARENOTPERMANENTANALTERNATIVEAPPROACHTOIMPROVEDURABILITYHASBEENTOCOVALENTLYFIXA“REACTIVE”CYCLODEXTRINDERIVATIVETOTHETEXTILEFIBRESURFACEANDTHESERVICEABILITYPROPERTIESOFTHETEXTILEPRODUCTMAYBERENEWEDWITHOUTREAPPLICATIONOFTHEFINISHFORCELLULOSICS,THEMOSTPROMISINGAPPROACHHASBEENTHEUSEOFAMONOCHLOROTRIAZINYLMCTΒCYCLODEXTRINDERIVATIVE,WHICHCANBECOVALENTLYFIXEDTONUCLEOPHILICSUBSTRATESBYASUBSTITUTIONREACTIONANDCONTAINSTWOTOTHREEREACTIVETRIAZINYLGROUPSPERCYCLODEXTRINRING1,12–15THEPERCENTAGEFIXATIONOFTHEREACTIVECYCLODEXTRINDERIVATIVETOTHESUBSTRATECANBEDETERMINEDBYFABRICWEIGHTGAINGRAVIMETRICMETHOD7ORTHEKJELDAHLMETHOD13ANDALTHOUGHBOTHMETHODSAREREPORTEDTOBESATISFACTORYNEITHERISSURFACESENSITIVENORSHOWSHOWTHEFIBRESURFACEMAYBEADVERSELYAFFECTEDBYTEXTILEPROCESSINGINTHISSTUDY,THEFIBRESURFACESAREEXAMINEDTOMONITORTHEDEPOSITIONANDINTERACTIONOFTHEMCTΒCYCLODEXTRINDERIVATIVESANDITSDURABILITYTOLAUNDERINGTHEXRAYPHOTOELECTRONSPECTROSCOPYXPSTECHNIQUEHASBEENUSEDTOCHARACTERIZETHENATUREOFTHESURFACESPECIESOUTER10NMONBOTHTENCELANDCOTTONFIBRESTREATEDWITHMCT00222461C?2006SPRINGERSCIENCEBUSINESSMEDIA,INCDOI101007/S10853006718362195NNNCLNAOCDFIGURE2CHEMICALSTRUCTUREOFTHEMONOCHLOROTRIAZINYLFUNCTIONALGROUPOFMCTCYCLODEXTRINMOLECULEFROMAFLOODGUNTOENSUREREPRODUCIBILITY,THESAMPLESWEREANALYSEDINDUPLICATEORTRIPLICATEWHEREAPPROPRIATECURVEFITTEDSPECTRAAREPRESENTEDTOCLEARLYDEFINETHEPEAKFORQUALITATIVEANALYSIS3RESULTSANDDISCUSSION31XPSANALYSISOFUNTREATEDANDMCTΒCYCLODEXTRINTREATEDTENCELTENCELISAREGENERATEDCELLULOSICFIBRE,WHICHISFREEOFNATURALIMPURITIESSUCHASNITROGENBASEDPROTEINS,PECTINSANDWAXESTYPICALLYASSOCIATEDWITHRAWUNSCOUREDCOTTONTHEN1SXPSSPECTRUMFORUNTREATED“CLEAN”TENCELSUBSTRATEREVEALEDTHATNITROGENSPECIESWEREABSENTFROMTHEFIBRESURFACES,FIG1SINCETHEMCTΒCYCLODEXTRINCONTAINSNITROGENBASEDTRIAZINYLFUNCTIONALITIES,ITSNITROGEN“LABEL”COULDBEUTILISEDASANELEMENTALTAGTOESTABLISHTHEPRESENCEOFTHEAPPLIEDFINISHATTHEFIBRESURFACES,FIG2INATYPICALN1SXPSSPECTRUM,NITROGENBOUNDTOCARBONINPRIMARY,SECONDARYORTERTIARYAMINESORAMIDES,OCCURSATABEVALUEOF3990–4002EV16,17THEN1SSPECTRAOFUNWASHEDANDWASHED5TREATEDTENCELCLEARLYINDICATETHEOBVIOUSPRESENCEOFSURFACENITROGENSPECIESATAPPROXIMATELYABEVALUEOF3995EVWHICHMAYBEASSIGNEDTOTHEPRESENCEOFATRIAZINYLSYSTEMOFMCTΒCYCLODEXTRIN,FIGS3AND4NITROGENSPECIESLOCATEDINC3N3AROMATICRINGSYSTEMSWOULDTYPICALLYOCCURATBEVALUESAROUND3992AND3994EV18THEPRESENCEOFNITROGENONTHEFABRICSURFACEINDICATESSTRONGCOVALENTBONDINGBETWEENTHEMCTΒCYCLODEXTRINANDTHECELLULOSICFIBRESURFACE,EVENAFTERFIVEWASHES32XPSANALYSISOFTENCELTREATEDWITHVARYINGLEVELSOFMCTΒCYCLODEXTRINTENCELFABRICSWERETREATEDWITHINCREASINGLEVELSOFTHEMCTΒCYCLODEXTRINDERIVATIVETODEMONSTRATETHEBUILDUPPROPERTIESOFTHEFINISHONTOTHESURFACEOFTHEFIBRETHETREATEDFABRICSWERETHENSUBJECTEDTOMULTIPLEISO105C06/C2SWASHCYCLESINORDERTOASSESSTHEDURABILITYOFTHESURFACEFINISHTHEATOMICNITROGENCONTENT,ASDETERMINEDBYXPS,WASUSEDASAMEASUREOFTHESURFACECONCENTRATIONOFTHEFINISHITISEVIDENTTHATTHEPERCENTAGE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簡(jiǎn)介:外文原文中文中文52405240字
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簡(jiǎn)介:1沈陽(yáng)理工大學(xué)學(xué)士學(xué)位論文附錄A34
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上傳時(shí)間:2024-03-12
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簡(jiǎn)介:中文中文40354035字畢業(yè)設(shè)計(jì)論文外文資料翻譯學(xué)院學(xué)院系化工學(xué)院專業(yè)業(yè)化學(xué)工程與工藝姓名名學(xué)號(hào)號(hào)外文出處外文出處JOURNALOFSOLGELSCIENCEANDTECHNOLOGY附件件1外文資料翻譯譯文;2外文原文。指導(dǎo)教師評(píng)語(yǔ)該同學(xué)翻譯忠于原文,語(yǔ)句比較連貫,意思基本表達(dá)清楚,是一篇合格的外文文獻(xiàn)譯文。簽名2013年3月15日用外文寫(xiě)附件附件1外文資料翻譯譯文外文資料翻譯譯文抗反射聚乙烯醇縮丁醛/二氧化硅混合物涂膜的制備與表征PVB防潮性與疏水性的效應(yīng)摘要摘要本文旨在介紹一種以硅酸乙酯為前驅(qū)物,聚乙烯醇縮丁醛為改良劑,通過(guò)溶膠凝膠催化方法制得的一種新型的改性抗反射涂膜。而AR涂膜和二氧化硅溶膠通過(guò)傅里葉變換紅外吸收光譜、粒子尺寸分析、透射電子顯微鏡、可編程流變儀、紫外可見(jiàn)分光光度法、概率測(cè)量法、原子力顯微鏡以及接觸角測(cè)量法進(jìn)行表征。實(shí)驗(yàn)表明,加入4﹪的PVB會(huì)大大增加AR涂膜的防潮性。用4﹪的PVB改性的AR涂膜在BK7基片中的光透射率近乎100﹪。對(duì)于未改性的AR涂膜與4﹪PVB改性的AR涂膜其水的接觸角分別為51°和53°。也就是說(shuō),改性后的涂膜沒(méi)有明顯的疏水性。將改性后的涂膜暴露在潮濕的環(huán)境中,其透射率最大值幾乎不變,而未改性的涂膜在兩周內(nèi)其透射率從998﹪急劇下降到965﹪。PVB改性AR涂膜具有良好的防潮性的原因可能是AR涂膜表面的PVB的吸附作用。關(guān)鍵字關(guān)鍵字抗反射涂層聚乙烯醇縮丁醛防潮性疏水性1引言引言從1980年開(kāi)始的制備有機(jī)無(wú)機(jī)復(fù)合材料開(kāi)始,溶膠凝膠技術(shù)就引起了人們的廣泛興趣。由于它具有很多優(yōu)點(diǎn),諸如良好的均勻性,低粗糙度,良好的沉積性,產(chǎn)量高,而且在膠片中還有良好的微結(jié)構(gòu)可控制性,溶膠凝膠法在玻璃界已經(jīng)廣泛的用于制備抗反射涂膜(AR涂膜),比如機(jī)動(dòng)車(chē)窗,太陽(yáng)能電池,激光系統(tǒng)。對(duì)于AR涂膜,透射率是其最重要的性質(zhì)之一。然而,對(duì)于傳統(tǒng)的純凈二氧化硅涂膜材料,由于其在潮濕環(huán)境下的吸水性,使其透射率大大降低。這個(gè)問(wèn)題使得這些涂膜不能很好的應(yīng)用到潮濕的環(huán)境中。通常,防潮性隨著涂膜表面的疏水基團(tuán)的增加而增加。近年來(lái),科研工作者對(duì)如何制備AR涂膜做了大量的研究。最有效的方式就是將有機(jī)分子或者聚合物支撐疏水基團(tuán)作為改性劑嫁接到二氧化硅
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簡(jiǎn)介:中文中文5460字本科畢業(yè)設(shè)計(jì)(論文)外文翻本科畢業(yè)設(shè)計(jì)(論文)外文翻譯(2013屆)題目學(xué)生姓名學(xué)生姓名學(xué)號(hào)指導(dǎo)教師指導(dǎo)教師專業(yè)班級(jí)專業(yè)班級(jí)所在學(xué)院所在學(xué)院化學(xué)工程與材料學(xué)院化學(xué)工程與材料學(xué)院提交日期提交日期2率密度。因此這對(duì)于發(fā)展電極提高電化學(xué)性能的改性方法是非常重要的。石墨氈電極的各種改性方法已經(jīng)在研究,其中包括金屬電鍍18、19,熱激活20和酸處理12、21、22。電化學(xué)氧化技術(shù)對(duì)于碳基材料的表面處理是一種有效的方法。這是因?yàn)樗梢蕴峁┰S多類型的表面含氧官能團(tuán)和增加表面粗糙度與此同時(shí),這技術(shù)的控制也相對(duì)簡(jiǎn)單,可以在溫和條件下進(jìn)行23。然而,全釩氧化液流電池的石墨氈電極的電化學(xué)氧化已經(jīng)很少報(bào)道。李等人只報(bào)道了,相對(duì)于未處理的石墨氈電極全釩氧化液流電池的活性已經(jīng)得到改良。在目前的文章中,VOVO??22/氧化還原反應(yīng)中的經(jīng)過(guò)電化學(xué)氧化的石墨氈(被氧化的石墨氈)的激活正被詳細(xì)研究。被氧化的石墨氈的表面形態(tài)、潤(rùn)濕性、表面含氧官能團(tuán)和電化學(xué)性質(zhì)在電化學(xué)氧化程度上呈現(xiàn)正常變化。這些結(jié)果有助于理解石墨氈的電化學(xué)氧化機(jī)理,這研究也為確定全釩氧化液流電池電極活化的最佳工藝參數(shù)提供了有用的理論指導(dǎo)。2.實(shí)驗(yàn)實(shí)驗(yàn)2121材料5毫米厚的聚丙烯腈基石墨氈樣本由上海七杰有限有限公司提供。994從沈陽(yáng)的海中天精細(xì)化工廠購(gòu)買(mǎi),濃硫酸質(zhì)量分OHVOSO424?數(shù)98來(lái)自廣州東香港化工廠。22樣品制備聚丙烯腈基石墨氈在電化學(xué)氧化前先切成15厘米15厘米大小,然后所有的樣品都用蒸餾水徹底清洗然后在70?C下48H烘干。石墨氈板作為陽(yáng)極,石墨板作為陰極。電化學(xué)氧化在1M硫酸溶液中發(fā)生。石墨氈電極15厘米15厘米用作陽(yáng)極是由在兩個(gè)聚氯乙烯板片之間壓一塊石墨氈做成,其中一個(gè)聚氯乙烯板片有10厘米10厘米的孔,石墨氈通過(guò)孔與電解液想通。另一邊的石墨氈與石墨片電流收集器連接。石墨氈樣品在100MACM?2的電流密度下對(duì)不同的氧化時(shí)段進(jìn)行電氧化。發(fā)生氧化的石墨氈被拿出來(lái)用蒸餾水清洗干凈,然后在70?C下48H烘干。23特性
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簡(jiǎn)介:中文中文5760字出處出處WIJENBERGJHOJ,STEEGHM,AARNTSMP,ETALELECTRODEPOSITIONOFMIXEDCHROMIUMMETALCARBIDEOXIDECOATINGSFROMATRIVALENTCHROMIUMFORMATEELECTROLYTEWITHOUTABUFFERINGAGENTJELECTROCHIMICAACTA,2015,173819826無(wú)緩沖劑從三價(jià)鉻離子的甲酸鹽電解液中電沉積混合無(wú)緩沖劑從三價(jià)鉻離子的甲酸鹽電解液中電沉積混合的碳化鉻氧化物鍍層的碳化鉻氧化物鍍層摘要摘要在旋轉(zhuǎn)的氣缸電極上實(shí)現(xiàn)了無(wú)緩沖劑從三價(jià)鉻離子電解質(zhì)中電沉積碳化鉻氧化物涂層并實(shí)現(xiàn)對(duì)質(zhì)量流量的精確控制。在平衡條件下,在PH23的電解質(zhì)溶液中,CRIII主要以CRHCOOH2O52的形式存在。電沉積的機(jī)理是通過(guò)對(duì)電流密度的控制,由于析氫反應(yīng)PH升高,三價(jià)鉻配體離子快速逐步地去離子化。三種不同的制度可以根據(jù)相關(guān)的電流密度和質(zhì)量流量定義。低電流密度時(shí)電極上沒(méi)有沉積,只是因?yàn)樵陔姌O上形成了可溶性的CRHCOOOHH2O4(制度1)。在一定的閾值電流密度下CRHCOOOH2H2O3沉積在電極上(制度2)。沉淀中的一部分三價(jià)鉻被還原為鉻金屬和甲酸溶液分解導(dǎo)致了鉻碳化物的形成。在制度2下沉淀物的組成和數(shù)量很大程度上依賴于電流密度、質(zhì)量流量和電解時(shí)間。在高電流密度下,酸堿平衡進(jìn)一步轉(zhuǎn)變?yōu)镃RHCOOOH3H2O2,在電極上形成組成主要為鉻氧化物的沉淀(制度3)。與制度2形成鮮明對(duì)比,制度3中沉淀的數(shù)量和組成隨著電流密度、質(zhì)量流量和電解時(shí)間幾乎不變。11簡(jiǎn)介簡(jiǎn)介鉻鍍層被廣泛應(yīng)用于很多領(lǐng)域,包括包裝領(lǐng)域的鋼鐵鍍鉻(ECCS)。ECCS包括一個(gè)精確尺寸的低碳鋼,底層是非常薄的鉻金屬鍍層,頂層是鉻氧化物。ECCS在高速連續(xù)的鋼帶鍍層線上被連續(xù)生產(chǎn),通過(guò)一個(gè)或更多的單元大約一米寬的足夠長(zhǎng)的鋼帶被運(yùn)輸?shù)姆浅??。鋼帶的快速運(yùn)動(dòng)導(dǎo)致了大量的湍流,導(dǎo)致了高的傳質(zhì)速率。高的質(zhì)量遷移率允許了高電流密度的使用。通常,沉積過(guò)程在幾秒內(nèi)完成。ECCS從六價(jià)鉻電解質(zhì)溶液中被生產(chǎn),但今天六價(jià)鉻被認(rèn)為是一種對(duì)環(huán)境有害的物質(zhì),有持續(xù)的安全問(wèn)題。到2017年歐洲已經(jīng)立法禁止使用六價(jià)鉻。過(guò)去十年的研究吧焦點(diǎn)放在了三價(jià)鉻電解質(zhì)溶液的發(fā)展,因?yàn)樗菬o(wú)毒的。從20世紀(jì)70年代中期,商業(yè)化三價(jià)鉻電鍍工藝就已經(jīng)被應(yīng)用于裝飾性鍍層。這種電解質(zhì)通常含有絡(luò)合劑(如甲酸鹽、醋酸、草酸、檸檬酸或甘氨酸)活化穩(wěn)的CRH2O63和PH緩沖液(通常為硼酸)防止水解反應(yīng)和羥橋反應(yīng),這是因?yàn)闅涞男纬蓪?dǎo)致陰極附近的PH升高最小。MANDICH在鉻化學(xué)上發(fā)表了兩部分綜述給出了鉻復(fù)合離子的水解、羥橋化、聚合和氧橋化的更進(jìn)一步的細(xì)節(jié)。宋等在旋轉(zhuǎn)圓盤(pán)電極上研究了甲酸和乙酸鹽作為絡(luò)合劑的三價(jià)鉻鍍液的鍍液組成、傳質(zhì)和外加電位對(duì)鉻沉積的影響。這項(xiàng)研究結(jié)果表明,鉻電沉積過(guò)程提供,包括66的CROHSO4,258的NA2SO4和710的水分。添加KCL提高電解液的導(dǎo)電率,添加KBR阻止或抑制三價(jià)鉻在陽(yáng)極氧化成六價(jià)鉻。通過(guò)加入硫酸把電解液的PH調(diào)節(jié)到23。通過(guò)使用恒溫浴加熱熱水循環(huán)的雙層玻璃容器使電解液的溫度恒定在50℃。23旋轉(zhuǎn)圓筒電極設(shè)置旋轉(zhuǎn)圓筒電極裝置使用,被設(shè)計(jì)為安裝三片的73MM的身體。基板材料的矩形毛坯被卷成一個(gè)圓筒形被焊接在SOUDRONICAFB1000罐體焊機(jī)。圓筒的高度為113MM。鋼筒的大的表面積(26DM2)有利于表面分析。鍍鉑鈦筒采用MAGNETO制作的特殊陽(yáng)極BV帶有一個(gè)內(nèi)徑為100MM的反電極。鈦的厚度為2MM,鈦涂層的質(zhì)量為50GM2。該陽(yáng)極與鋼柱對(duì)稱。該陽(yáng)極通過(guò)插入塑料物而部分分離。對(duì)主電流密度進(jìn)行優(yōu)化,使氣缸的局部電流密度與施加在除了兩個(gè)邊的幾乎整個(gè)表面區(qū)域的電流密度完全相等。用埃爾西版61軟件包計(jì)算鋼筒主電流密度的分布。對(duì)于計(jì)算的主電流分布,兩個(gè)微分方程求解這一單元幾何形狀的幾何數(shù)值拉普拉斯方程(▽2Φ0)和歐姆定律(IK▽?duì)担?,其中Φ是電壓V,I是電流密度AM2,K是電導(dǎo)率SM1。當(dāng)陽(yáng)極的活動(dòng)高度為103MM時(shí),鋼筒中心的實(shí)際電流密度與所施加的電流密度完全相等。圖一,鋼筒中心(X0)到邊緣(X05H)的主電流的分布。由于較高轉(zhuǎn)速時(shí)有渦旋產(chǎn)生,所以RCE設(shè)備的最高轉(zhuǎn)速為15RPS(轉(zhuǎn)/秒)相對(duì)應(yīng)Ω0767S07。由于RCS的質(zhì)量流量與轉(zhuǎn)速成正比,所以Ω07逐漸從1S07增加到6S07。24表面分析241XRF用X射線熒光光譜儀(XRF)測(cè)定鉻的總含量。該儀器具有帶有8個(gè)位置的樣品盤(pán),可以測(cè)定直徑為40MM的圓形樣品。XRF測(cè)定的鋼基體的鉻信號(hào)值是修正后的。242XPS通過(guò)使用14866EV的ALKΑ單色射線將X射線光電子能譜(XPS)和深度剖面記錄在KRATOSAXISULTRA。測(cè)得的光斑大小為700ΜM300ΜM。使用4KEV
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簡(jiǎn)介:38中文中文29742974字出處出處SENSORSANDACTUATORSBCHEMICAL,2008,13113013051外文資料翻譯譯文外文資料翻譯譯文具有高靈敏度的甲醛氣體傳感器的制備及其氣敏特性相對(duì)甲醛混有氧化鉻的氧化銦氣體傳感器特性已經(jīng)研究過(guò)了。間接加熱式氣體傳感器是用敏感材料進(jìn)行制備的。最終的材料的狀態(tài)和傳感層的形態(tài)通過(guò)X射線衍射和掃描電子顯微鏡分別在焙燒前后觀察到其特點(diǎn)。操作溫度對(duì)傳感器響應(yīng)的影響氧化鉻和氧化銦傳感器的氣體濃度特性的對(duì)比已經(jīng)研究過(guò)了。結(jié)果表明,在低操作溫度該傳感器對(duì)于甲醛具有良好的反應(yīng)性能,使他們成為甲醛氣體檢測(cè)最有希望的候選材料。1介紹作為一個(gè)重要的工業(yè)化學(xué)品,甲醛被應(yīng)用于制造業(yè),建筑板,膠合板和漆這樣的材料。此外,它還是消費(fèi)產(chǎn)品中一個(gè)中間添加物,如洗滌劑和肥皂。由于其殺菌性能也可用于藥理學(xué)和藥物中。然而,調(diào)查結(jié)果表明,因?yàn)樗菗]發(fā)性有害化合物,所以甲醛會(huì)對(duì)人體造成許多損害。因此,需要一種有效的方法來(lái)監(jiān)測(cè)甲醛進(jìn)而進(jìn)行氣體環(huán)境測(cè)量與控制。制造氣體傳感器被認(rèn)為是一個(gè)理想的監(jiān)測(cè)氣體的手段。我們目前的調(diào)查主要涉及與甲醛的檢測(cè)。雖然半導(dǎo)體金屬氧化物氣體傳感器提供了對(duì)有毒氣體或可燃性氣體的安全檢測(cè),但是他們?nèi)匀挥幸欢ǖ木窒扌?,如靈敏度,選擇性,長(zhǎng)期穩(wěn)定性等等。為了克服半導(dǎo)體金屬氧化物氣體傳感器的缺點(diǎn),半導(dǎo)體金屬氧化物的制備與摻雜的研究已經(jīng)做過(guò)了。氧化銦是一個(gè)有希望的具有寬禁帶的半導(dǎo)體材料(370電子伏特),其電子濃度主要取決于計(jì)量缺陷的濃度(如氧空位)就像其他金屬氧化物半導(dǎo)體。就傳感機(jī)制來(lái)說(shuō),顆粒的大小,缺陷,表面與界面的性能和化學(xué)計(jì)量學(xué)直接影響了傳感器表面的氧化物種類的狀態(tài)和數(shù)量,最后影響了金屬氧化物傳感器的性能。因此,為了提高并改善氣體傳感性能(敏感性,選擇性,較好的熱穩(wěn)定性和較低的操作溫度),氧化銦通常用于納米結(jié)構(gòu)形式或摻雜合適的貴金屬和金屬氧化物。作為一個(gè)單組分氧化物,由于其良好的靈敏度,氧化銦是一種很有前途的氧化性氣體檢測(cè)的候選者。因此,當(dāng)其他金屬氧化物摻雜氧化銦,對(duì)于不同的氣體可調(diào)諧的氣體靈敏度也不同。他們已經(jīng)很好的研究了檢測(cè)大部分重要?dú)怏w的傳感器材料,如乙醇,一氧化碳,二氧化氮,和氫氣。然而,研究很少集中在甲醛傳感器的材料特性。在本次調(diào)查中,用固態(tài)合成技術(shù)制備氧化鎘和氧化銦的混合物,通過(guò)X射線衍射和掃描電鏡圖像來(lái)觀察其特點(diǎn)?;诨k和氧化銦的混合物的間接加熱的氣體傳感器就被制備好了。甲醛傳感器中混合物的特性也就確定了。40操作溫度對(duì)反應(yīng)有重大影響。有趣的是,反應(yīng)首先逐漸增加,然后隨著操作溫度的提高減少。可以看出,對(duì)于甲醛氣體在低溫范圍內(nèi),基于氧化鉻和氧化銦的傳感器具有優(yōu)異的氣敏特性。在95攝氏度它展出了對(duì)甲醛氣體最高的響應(yīng)。較低的工作溫度在應(yīng)用中是一個(gè)優(yōu)點(diǎn)。如圖4所示,響應(yīng)的抵押–氧化銦基于傳感器的氧化鉻和氧化銦在95度操作時(shí)的響應(yīng)展示了對(duì)氣體濃度的良好依賴性。該傳感器對(duì)酒精和汽油有著非常小的反應(yīng),但對(duì)于甲醛氣體有著較大響應(yīng)。百萬(wàn)分之十的甲醛氣體的反應(yīng)超過(guò)了百萬(wàn)之八十的甲醛氣體的響應(yīng)。本反應(yīng)是大大高于最近報(bào)道氧化鋅和氧化鉛,三氧化鎢和氧化鉛,鎳,和基于甲醛氣體的LA068PB032FEO3。這種氣體傳感器展現(xiàn)了對(duì)甲醛氣體的較大反應(yīng)和對(duì)酒精與汽油的較高選擇性。這一結(jié)果表明,氧化鉻和氧化銦是一個(gè)良好的檢測(cè)甲醛氣體的氣敏材料,可用于監(jiān)測(cè)和控制甲醛氣體。一個(gè)良好的反應(yīng)和快速響應(yīng)、恢復(fù)時(shí)間可以用這種傳感器在最佳工作溫度95攝氏度下進(jìn)行觀察。針對(duì)不同甲醛氣體濃度10–100PPM的器皿傳感器如圖5所示。作為一個(gè)高靈敏度的傳感器,它可以測(cè)量非常低濃度,甚至百萬(wàn)分之一。隨著甲醛氣體濃度的增加輸出電壓的增加呈線性關(guān)系并且有較短的響應(yīng)時(shí)間。響應(yīng)時(shí)間和恢復(fù)時(shí)間(定義為達(dá)到最終平衡值90)為2分鐘,恢復(fù)時(shí)間為4分鐘。氣敏機(jī)理是基于氧化鉻和氧化銦材料的電導(dǎo)的變化。材料的表面對(duì)氧的吸收影響了氧化鉻和氧化銦傳感器的導(dǎo)電性。氧的吸附取決于顆粒大小,較大的材料面積,和合適的傳感器操作溫度。隨著空氣中溫度的增加,氧的狀態(tài)被吸附在氧化鉻和氧化銦材料的表面的氧的狀態(tài)在下面的反應(yīng)中發(fā)生。氧從材料中捕獲電子,導(dǎo)致了空穴濃度的增加和電子濃度的減少。當(dāng)傳感器接觸甲醛氣體時(shí),被捕獲的電子以吸附狀態(tài)被釋放,導(dǎo)致傳感器電阻減小。因此,氧化鉻和氧化銦傳感器甲醛氣體的減少是敏感的。該傳感器具有良好的穩(wěn)定性(沒(méi)有顯示的數(shù)據(jù))。穩(wěn)定性機(jī)制更為復(fù)雜和進(jìn)一步的工作是得到了一一個(gè)明確的認(rèn)識(shí)。4總結(jié)通過(guò)固態(tài)合成技術(shù)氧化鉻和氧化銦樣本的制備甲醛探測(cè)的傳感材料已被證明是可行的。制作好的傳感器顯示了很大程度的反應(yīng),高選擇性,快速反應(yīng),和在低操作溫度時(shí)良好的恢復(fù)性。實(shí)驗(yàn)結(jié)果表明了混有氧化鉻的氧化銦氣體傳感器的材料潛力。鳴謝這項(xiàng)工作得到了中國(guó)國(guó)家自然科學(xué)基金會(huì)和中國(guó)云南省自然科學(xué)基金支持。
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簡(jiǎn)介:自組裝石墨烯碳納米管復(fù)合膜制備超級(jí)電容器1中文2890字出處出處THEJOURNALOFPHYSICALCHEMISTRYLETTERS,2009,12467470自組裝石墨烯碳納米管復(fù)合膜制備超級(jí)電容器DINGSHANYUANDLIMINGDAIDEPARTMENTOFCHEMICALENGINEERING,CASEWESTERNRESERVEUNIVERSITY,CLEVELAND,OHIO44106摘要在PEI陽(yáng)離子存在的條件下,通過(guò)還原剝離的氧化石墨制得穩(wěn)定的石墨烯片水溶液分散體系。得到的可溶于水的被PEI改進(jìn)的石墨烯薄片與有氧酸多層碳納米管經(jīng)順序自組裝形成復(fù)合碳薄膜。這些合成膜被證實(shí)擁有明確界定的納米孔的互聯(lián)網(wǎng)絡(luò)碳結(jié)構(gòu),其被期待制成超級(jí)電容器,同時(shí)顯示接近矩形的伏安循環(huán),即使在較高的掃描速率1V/S,平均比電為120F/G。關(guān)鍵詞納米顆粒和納米結(jié)構(gòu)由于其獨(dú)特的電性能、機(jī)械性能和大的比表面積,具有二維2D碳納米結(jié)構(gòu)的石墨烯納米薄膜(GNS)將成為一種新型的有前途的材料,在制動(dòng)器、太陽(yáng)能電池、場(chǎng)致發(fā)射裝置、場(chǎng)效應(yīng)晶體管、超級(jí)電容器和電池方面有很大的應(yīng)用前景。17把石墨烯薄膜作為儲(chǔ)能電極的合成膜成為特別有吸引力的選擇項(xiàng)目。8,9在這種情形下,在納米級(jí)別上通過(guò)控制合成膜的組成和結(jié)構(gòu)來(lái)改進(jìn)合成膜的性能非常關(guān)鍵。因此,使石墨烯薄膜具有可控加工的性能是重要的。近來(lái),通過(guò)溶液的氧化還原把剝離的石墨轉(zhuǎn)變成氧化石墨烯GOS制得溶解狀態(tài)的GNS,10溶解狀態(tài)的GNS制成GN功能膜有多種溶液加工方法,如過(guò)濾,11溶劑蒸發(fā)成膜,12電泳沉積13和LANGMUIRBLODGETT沉積14。然而上面提到的大部分方法由于薄膜的結(jié)構(gòu)性質(zhì)難以控制,石墨烯團(tuán)聚導(dǎo)致的表面積減小將影響其能量?jī)?chǔ)藏。因此,在儲(chǔ)能方面的應(yīng)用,我們想用一維1D碳納米管CNTS物理分離二維石墨烯片保持石墨烯高的比表面積。自組裝石墨烯碳納米管復(fù)合膜制備超級(jí)電容器3圖1A數(shù)碼照片顯示出濃度為025毫克/毫升水性分散的還原氧化石墨烯溶液,在PEI存在下;B在PEIGN體系中分散的單層石墨烯的AFM圖;C剖面顯示厚度的PEIGN片狀。這些獲得的被PEI修飾的石墨烯可進(jìn)一步利用拉曼光譜儀(圖S1A,支持信息)、傅里葉紅外光譜儀(圖S1B)和X射線光電能譜XPS分析,圖2是GO和被PEI修飾的石墨烯的XPS光譜。圖2A顯示的是PEIGN的XPS光譜,其N的峰與GO的XPS光譜相比,清晰的表明PEI鏈吸附在合成GNS上。正如預(yù)期的那樣,在圖2B中的GO的C1S光譜波峰在2881和2863EV,這是由于C=O和CO鍵的影響。相比之下,PEIGN的C1光譜由于C=O和CO官能團(tuán)的存在會(huì)出現(xiàn)明顯的波峰降低圖2C。GO的表面氧基團(tuán)預(yù)計(jì)達(dá)到311,但是在用混合有PEI的肼處理后氧含量降至89。結(jié)果表明在PEI和肼的還原下有大量的脫氧反應(yīng)發(fā)生。這期間,在PEIGN中氧的百分?jǐn)?shù)達(dá)到81,表明PEI鏈連接在石墨烯薄膜。此外,PEIGN的C1S和N1S的XPS光譜表明胺NH2NH3C1S在2878EV和N1S在3995EV和酰胺鍵NC=O存在,24表明一些PEI鏈已經(jīng)經(jīng)由酰胺鍵的形成在石墨烯表面形成共價(jià)連接。圖2和GO和PEIGN的XPS光譜圖2A寬掃描光譜;BGO的XPSC1S光譜;CPEIGN的XPSC1S光譜;DPEIGN的XPSN1光譜。PEIGN表面上大量的NH2基團(tuán)能夠得到質(zhì)子(NH3)通過(guò)一定的PH調(diào)節(jié),使
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簡(jiǎn)介:SURFACEANDCOATINGSTECHNOLOGY1482001171–17802578972/01/SEEFRONTMATTER?2001ELSEVIERSCIENCEBVALLRIGHTSRESERVEDPIIS02578972?01013366ELECTRODEPOSITIONANDSLIDINGWEARRESISTANCEOFNICKELCOMPOSITECOATINGSCONTAININGMICRONANDSUBMICRONSICPARTICLESIGARCIA,JFRANSAER,JPCELISA,B,AAKATHOLIEKEUNIVERSITEITLEUVEN,DEPARTMENTMTM,KASTEELPARKARENBERG44,B3001LEUVEN,BELGIUMANATIONALCENTERFORMETALLURGICALRESEARCHCENIMCSIC,DEPARTMENTOFCORROSIONANDPROTECTION,AVGREGORIODELAMO8,28040MADRID,BSPAINRECEIVED1MARCH2001ACCEPTED21JUNE2001ABSTRACTSICPARTICLESOFTHREEDIFFERENTSIZES,NAMELY5,07AND03MM,WERECODEPOSITEDWITHNICKELFROMWATTS’SOLUTIONSITWASFOUNDTHATFORAGIVENNUMBERDENSITYOFPARTICLESINTHEPLATINGSOLUTION,THENUMBERDENSITYOFPARTICLESINTHECOATINGINCREASESWITHDECREASINGPARTICLESIZETHEFRICTIONANDWEARBEHAVIOROFTHESECOMPOSITECOATINGSWASEVALUATEDINUNIANDBIDIRECTIONALSLIDINGTESTSAGAINSTCORUNDUMBALLSTHEBESTSLIDINGWEARRESISTANCEWASOBTAINEDWITHNI–SICCOMPOSITECOATINGSCONTAINING4–5VOLSUBMICRONSICPARTICLES?2001ELSEVIERSCIENCEBVALLRIGHTSRESERVEDKEYWORDSELECTRODEPOSITIONCOMPOSITESWEARNICKELSIC1INTRODUCTIONELECTRODEPOSITEDCOMPOSITECOATINGSCONSISTOFAMETALORALLOYMATRIXCONTAININGADISPERSIONOFSECONDPHASEPARTICLESW1–3XTHESEPARTICLESCANBEHARDOXIDEORCARBIDEPARTICLES,SUCHASALO,SIC,TIO,WC,SIO2322ORDIAMOND,ASOLIDLUBRICANT,SUCHASPTFE,GRAPHITEORMOS,OREVENLIQUIDCONTAININGMICROCAPSULESW4XTO2IMPROVEWEARRESISTANCEANDYORTOREDUCEFRICTIONELECTROPLATEDCOMPOSITECOATINGSCONTAININGMICRONSIZEDPARTICLESAREUSEDASWEARRESISTANTCOATINGSW5–7X,EGNICKEL–SICINCARENGINESW1,8–10XWITHTHEINCREASINGAVAILABILITYOFNANOPARTICLES,THEREISAGROWINGINTERESTINTHEELECTROLYTICANDELECTROLESSCODEPOSITIONOFNANOPARTICLESW11XTHEMAJORCHALLENGESOFTHECODEPOSITIONOFNANOPARTICLESSEEMTOBETHECODEPOSITIONOFASUFFICIENTNUMBEROFPARTICLES,ANDAVOIDINGTHEAGGLOMERATIONOFPARTICLESSUSPENDEDINTHEPLATINGSOLUTIONSCORRESPONDINGAUTHORTELQ3415538900FAXQ3415347425EMAILADDRESSIGARCIACENIMCSICESIGARCIAINTHISWORK,THEELECTROLYTICCODEPOSITIONOFMICRONANDSUBMICRONSICPARTICLESFROMNICKELWATTS’SOLUTIONS,ANDTHESLIDINGWEARRESISTANCEOFSUCHNICKELCOMPOSITECOATINGSAREINVESTIGATEDTHEEFFECTOFPARTICLESIZEANDNUMBEROFPARTICLESSUSPENDEDINTHEPLATINGSOLUTIONONTHENUMBEROFCODEPOSITEDPARTICLESISREPORTEDTHECODEPOSITIONRESULTSANDAMODELBASEDONTHENUMBERDENSITYOFPARTICLESCODEPOSITEDAREDISCUSSEDTHEEFFECTOFPARTICLESIZEONTHECODEPOSITIONPROCESSOFMICRONANDSUBMICRONSIZEDNONBROWNIANPARTICLESISCLARIFIEDTHEEFFECTOFCODEPOSITEDSUBMICRONPARTICLESONTHEWEARRESISTANCEOFCOMPOSITENI–SICCOATINGSISDISCUSSED2EXPERIMENTALTHEPLATINGSOLUTIONUSEDWASASTANDARDNICKELWATTS’SOLUTIONTHECOMPOSITIONOFTHEPLATINGSOLUTIONANDTHEPLATINGPARAMETERSAREGIVENINTABLE1SICPARTICLESWITHAMEANDIAMETEROF03BSC21C,PERFORMANCECERAMICS,JAPAN,07BS07,ELEKTROSCHMELZWERKKEMPTEN,GERMANYAND5MME110?4000,NORTON,NORWAYWEREUSEDALLPARTICLESWEREUSEDASRECEIVED173IGARCIAETAL/SURFACEANDCOATINGSTECHNOLOGY1482001171–178FIG2VOLUMETRICWEARFACTORUNDERUNIDIRECTIONALSLIDINGONCOMPOSITENI–SICCOATINGSCONTAININGDIFFERENTVOLSICPARTICLESOFTHREEDIFFERENTSIZESDATAFORPUREELECTROLYTICNICKELAREALSOGIVENEDNICKELREFERENCEFIG3VOLUMETRICWEARFACTORUNDERBIDIRECTIONALSLIDINGONCOMPOSITENI–SICCOATINGSCONTAININGDIFFERENTVOLSICPARTICLESOFTHREEDIFFERENTSIZESDATAFORPUREELECTROLYTICNICKELAREALSOGIVENEDNICKELREFERENCEPOSITIONISOBTAINEDWITH07MMPARTICLESQUITEUNEXPECTEDLYW13X,THE03MMSICPARTICLESCODEPOSITMORETHANTHE07MMPARTICLESAPOSSIBLEREASONCOULDBETHEDIFFERENCEINTHESURFACECONDITIONOFTHESESICPARTICLESOBTAINEDFROMDIFFERENTPRODUCERSANOTHERREASONCOULDBETHEAGGLOMERATIONOFTHE03MMPARTICLESINTHEPLATINGSOLUTIONTHEWEARTRACKSONTHECOMPOSITENI–SICCOATINGSAFTERUNIANDBIDIRECTIONALSLIDINGTESTSHAVEABLACKAPPEARANCE,ANDSHOWSCRATCHESPARALLELTOTHEDIRECTIONOFMOTIONSUCHSCRATCHESARETYPICALFORABRASIVEWEARFORALLNI–SICCOMPOSITECOATINGSTESTED,THECOEFFICIENTOFFRICTIONISAPPROXIMATELY05DURINGTHEFIRSTFEWSLIDINGCYCLESAFTERTHERUNNINGINPHASE,THECOEFFICIENTOFFRICTIONOFNICKELCOATINGSCONTAINING07OR03MMSICPARTICLESISAPPROXIMATELY029THATCOEFFICIENTOFFRICTIONISLOWERTHANTHEVALUEOF034OBSERVEDONNICKELCOATINGSCONTAINING5MMSICPARTICLESATACOMPARABLEVOLUMEPERCENTOFCODEPOSITEDPARTICLESONTHEOTHERHAND,FOREACHSICPARTICLESIZEINVESTIGATED,THECOEFFICIENTOFFRICTIONINCREASESWITHINCREASINGVOLUMEPERCENTOFSICPARTICLESINTHECOATINGS,FROMAPPROXIMATELY034TO047INTHECASEOF5MMSICPARTICLES,ANDFROM028TO030INTHECASEOF07MMPARTICLESTHEWEARLOSSONNI–SICCOMPOSITECOATINGSCONTAININGSICPARTICLESOFDIFFERENTSIZES,AFTERSLIDINGAGAINSTCORUNDUMBALLSINUNIANDBIDIRECTIONALWEARTESTS,ISSHOWNINFIGS2AND3,RESPECTIVELYTHEVOLUMETRICWEARLOSSONPURENICKELCOATINGSANDCOMPOSITENI–SICCOATINGSINUNIDIRECTIONALSLIDINGWEARTESTSISAPPROXIMATELYTWOORDERSOFMAGNITUDELOWERTHANTHATNOTEDINBIDIRECTIONALSLIDINGTESTSTHISISCONSISTENTWITHSLIDINGWEARDATAOBTAINEDONHARDCERAMICCOATINGS,SUCHASTIN,SHOWINGAMUCHLOWERWEARRATEUNDERUNITHANUNDERBIDIRECTIONALSLIDINGTESTCONDITIONSW14XHOWEVER,UNDERUNIDIRECTIONALSLIDING,COMPOSITENICKELCOATINGSCONTAINING5MMSICPARTICLESEXHIBITALOWERWEARRESISTANCEWITHINCREASINGAMOUNTSOFSICTHANPURENICKELCOATINGSREFERREDTOASEDNICKELREFERENCEINFIG2ONTHECONTRARY,COM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簡(jiǎn)介:ARSENICINTHEENVIRONMENTBIOLOGYANDCHEMISTRYPROSUNBHATTACHARYAA,?,ALANHWELCHB,KENNETHGSTOLLENWERKC,MIKEJMCLAUGHLIND,JOCHENBUNDSCHUHE,GPANAULLAHFAKTHINTERNATIONALGROUNDWATERARSENICRESEARCHGROUP,DEPARTMENTOFLANDANDWATERRESOURCESENGINEERING,ROYALINSTITUTEOFTECHNOLOGYKTH,SE10044STOCKHOLM,SWEDENBNEVADAWATERSCIENCECENTER,UNITEDSTATESGEOLOGICALSURVEY,2730NDEERRUNROAD,CARSONCITY,NV89701USACUNITEDSTATESGEOLOGICALSURVEY,MS413,BOX25046,FEDERALCENTER,DENVER,CO80225,USADCSIROLANDANDWATER/UNIVERSITYOFADELAIDE,PMB2,GLENOSMOND,SA5064,AUSTRALIAEINTERNATIONALTECHNICALCOOPERATIONPROGRAMMECIMGTZ/BA,GERMANY,INSTITUTOCOSTARRICENSEDEELECTRICIDADICE,PYSA,APARTADOPOSTAL10032,1000SANJOSE,COSTARICAFCIMMYT,BANGLADESH,POBOX6057GULSHAN,DHAKA1212,BANGLADESHRECEIVED6FEBRUARY2007RECEIVEDINREVISEDFORM25FEBRUARY2007ACCEPTED27FEBRUARY2007AVAILABLEONLINE16APRIL2007ABSTRACTARSENICASDISTRIBUTIONANDTOXICOLOGYINTHEENVIRONMENTISASERIOUSISSUE,WITHMILLIONSOFINDIVIDUALSWORLDWIDEBEINGAFFECTEDBYASTOXICOSISSOURCESOFASCONTAMINATIONAREBOTHNATURALANDANTHROPOGENICANDTHESCALEOFCONTAMINATIONRANGESFROMLOCALTOREGIONALTHEREAREMANYAREASOFRESEARCHTHATAREBEINGACTIVELYPURSUEDTOADDRESSTHEASCONTAMINATIONPROBLEMTHESEINCLUDENEWMETHODSOFSCREENINGFORASINTHEFIELD,DETERMININGTHEEPIDEMIOLOGYOFASINHUMANS,ANDIDENTIFYINGTHERISKOFASUPTAKEINAGRICULTUREREMEDIATIONOFASAFFECTEDWATERSUPPLIESISIMPORTANTANDRESEARCHINCLUDESASSESSINGNATURALREMEDIATIONPOTENTIALASWELLASPHYTOREMEDIATIONANOTHERAREAOFACTIVERESEARCHISONTHEMICROBIALLYMEDIATEDBIOGEOCHEMICALINTERACTIONSOFASINTHEENVIRONMENTIN2005,ACONFERENCEWASCONVENEDTOBRINGTOGETHERSCIENTISTSINVOLVEDINMANYOFTHEDIFFERENTAREASOFASRESEARCHINTHISPAPER,WEPRESENTASYNTHESISOFTHEASISSUESINTHELIGHTOFLONGSTANDINGRESEARCHANDWITHREGARDSTOTHENEWFINDINGSPRESENTEDATTHISCONFERENCETHISCONTRIBUTIONPROVIDESABACKDROPTOTHEISSUESRAISEDATTHECONFERENCETOGETHERWITHANOVERVIEWOFCONTEMPORARYANDHISTORICALISSUESOFASCONTAMINATIONANDHEALTHIMPACTSCROWNCOPYRIGHT?2007PUBLISHEDBYELSEVIERBVALLRIGHTSRESERVEDKEYWORDSARSENICCONTAMINATIONPOLLUTIONGROUNDWATERTUBEWELLSCREENINGFIELDTESTKITHEALTHSAFEAQUIFERSAGRICULTURESOILSMININGENVIRONMENTPHYTOREMEDIATIONSORPTIONREMEDIATION1INTRODUCTION11LOCATIONANDSCALEOFPROBLEMARSENICASHASBEENDETECTEDINGROUNDWATERINSEVERALCOUNTRIESOFTHEWORLD,WITHCONCENTRATIONLEVELSEXCEEDINGTHEWHODRINKINGWATERGUIDELINEVALUEOF10ΜG/LWHO,2001ASWELLASTHENATIONALREGULATORYSTANDARDSEG50ΜG/LININDIAANDBANGLADESH,AHMEDETAL,2004MUKHERJEEETAL,2006ARSENICINGROUNDWATERISOFTENASSOCIATEDWITHGEOLOGICSOURCES,BUTINSOMELOCATIONSANTHROPOGENICINPUTSCANBEEXTREMELYIMPORTANTINGESTIONOFGEOGENICASFROMGROUNDWATERSOURCESISMANIFESTEDASCHRONICHEALTHDISORDERSINMOSTOFTHEAFFECTEDREGIONSOFTHEWORLDBGSFAX4684110775EMAILADDRESSPROSUNKTHSEPBHATTACHARYA00489697/SEEFRONTMATTERCROWNCOPYRIGHT?2007PUBLISHEDBYELSEVIERBVALLRIGHTSRESERVEDDOI101016/JSCITOTENV200702037MMAIIIISMORETOXICTHANASIIIANDASVVIZPETRICKETAL,2000,200114AGRICULTURETHEADVERSEEFFECTSOFASINGROUNDWATERUSEDFORIRRIGATIONWATERONCROPSANDAQUATICECOSYSTEMSISALSOOFMAJORCONCERNINADDITIONTOPOTENTIALHUMANHEALTHIMPACTSCAUSEDBYINGESTIONOFFOODCONTAININGAS,THEPOTENTIALFORREDUCEDCROPYIELDDUETOITSBUILDUPINTHESOILISANACTIVEAREAOFRESEARCHTHEFATEOFASINAGRICULTURALSOILSISOFTENLESSWELLSTUDIEDCOMPAREDTOGROUNDWATER,ANDINGENERALHASBEENSTUDIEDINTHECONTEXTOFASUPTAKEBYDIFFERENTPLANTSHUQETAL,2001,2006DASETAL,2004ALRMALLIETAL,2005CORRELLETAL,2006NAIDUETAL,2006CROPQUALITYANDTHEEFFECTOFASONCROPQUALITYANDYIELDISBECOMINGAMAJORWORLDWIDECONCERN,PARTICULARLYFORRICEWHICHFORMSTHESTAPLEFORMANYSOUTHASIANCOUNTRIESWHEREGROUNDWATERISWIDELYUSEDFORIRRIGATIONMEHARGANDRAHMAN,2003INARECENTSTUDYITWASREPORTEDTHATIRRIGATIONHASINCREASEDINBANGLADESHSINCE1970,WHILESINCE1980,THEAREAUNDERGROUNDWATERIRRIGATIONFORTHECULTIVATIONOFBORORICEHASINCREASEDBYALMOSTANORDEROFMAGNITUDEHARVEYETAL,2005BASEDONAVAILABLEINFORMATIONONTHEDISTRIBUTIONOFASCONCENTRATIONINGROUNDWATERBGSANDDPHE,2001ANDTHEAREAUNDERSHALLOWTUBEWELLIRRIGATIONBADC,2005,SAHA2006ESTIMATEDTHATAPPROXIMATELY1000METRICTONSOFASISCYCLEDWITHIRRIGATIONWATERDURINGTHEDRYSEASONOFEACHYEARRICEYIELDHASBEENREPORTEDTODECREASEBY10ATACONCENTRATIONOF25MG/KGASINSOILXIONGETAL,1987AGREENHOUSESTUDYBYABEDINETAL2002REVEALEDREDUCEDYIELDOFALOCALVARIETYOFRICEBR11IRRIGATEDWITHWATERHAVINGASCONCENTRATIONSINTHERANGEOF02TO8MG/LTHEACCUMULATIONOFASINRICEFIELDSOILSANDITSINTRODUCTIONINTOTHEFOODCHAINTHROUGHUPTAKEBYTHERICEPLANTISOFMAJORCONCERNDUXBURYETAL,200315ANTHROPOGENICARSENICLARGEQUANTITIESOFASARERELEASEDINTOTHEENVIRONMENTTHROUGHINDUSTRIALACTIVITIES,WHICHCANBEDISPERSEDWIDELYANDASSUCHPLAYANIMPORTANTROLEINTHECONTAMINATIONOFSOILS,WATERS,ANDAIRNRIAGU,1989JACKSANDBHATTACHARYA,1998JUILLOTETAL,1999MATSCHULLAT,2000PACYNAANDPACYNA,2001ELEVATEDCONCENTRATIONSOFASINSOILSOCCURONLYLOCALLY,BUTINAREASOFFORMERINDUSTRIALAREASITMAYCAUSEENVIRONMENTALCONCERNNRIAGU,1994SMITHETAL,1998KABATAPENDIASANDPENDIAS,2001ALTHOUGHMANYMINERALSCONTAINASCOMPOUNDS,THEANTHROPOGENICCONTRIBUTIONTOTHEENVIRONMENTINTHEPASTACCOUNTEDFOR82,000METRICTONS/YEARWORLDWIDENRIAGUANDPACYNA,1988INORGANICASCOMPOUNDSSUCHASCALCIUMARSENATE,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簡(jiǎn)介:STUDIESONELECTROLESSNICKEL–PTFECOMPOSITECOATINGSKNSRINIVASANANDSJOHNELECTROLESSDEPOSITIONOFNICKELBASEDCOMPOSITESPRODUCESOUTSTANDINGTRIBIOLOGICALBEHAVIOURTHESECOMPOSITECOATINGSAREFORMEDBYADDITIONTOTHEELECTROLESSNICKELSOLUTIONOFTHEMATERIALTOBECODEPOSITED,INPOWDERFORM,ANDBYMAINTAININGITINSUSPENSIONDURINGTHEDEPOSITIONPROCESSSOTHATITISINCORPORATEDINTOTHEDEPOSITTHEMOSTCOMMONLYUSEDHARDDISPERSEDCOMPOUNDSARESIC,DIAMONDPOWDER,ALUMINA,TIC,BN,CHROMIUMCARBIDEORWCRECENTLY,ELECTROLESSNICKELCONTAININGPTFEASACOMPOSITEMATERIALHASBEENUSEDBECAUSEITISUNIFORM,HIGHLYADHERENT,HARDWEARING,DRYLUBRICATING,NONGALLING,HASALOWERCOEFFICIENTOFFRICTIONANDGOODCORROSIONRESISTANCEPROPERTIESTHEPRESENTPAPERSTUDIESTHEEFFECTOFPTFEINANELECTROLESSNI–ACIDBATHONTHERATEOFDEPOSITION,INCORPORATIONOFPTFEANDPHOSPHOROUSCONTENTINTHEDEPOSIT,WEARANDCORROSIONRESISTANCEKEYWORDSELECTROLESSCOMPOSITES,CHEMICALDEPOSITION,NICKEL–PHOSPHOROUS–PTFECOMPOSITES,COMPOSITECOATINGINTRODUCTIONANELECTRODEPOSITEDCOMPOSITEPLATINGISAUNIFORMDISPERSIONOFSMALLDISCRETEPARTICULATEMATTERDELIBERATELYCODEPOSITEDWITHINAMETALLICCOATING1–3ELECTROLESSNICKELPHOSPHOROUSCOATINGSHAVEMANYPROPERTIESTHATARESUPERIORTOTHOSEOFELECTRODEPOSITEDNICKEL4BECAUSEOFTHEPHOSPHOROUSCONTENT,ELECTROLESSNICKELISHARDERANDHASBETTERCORROSIONRESISTANCE5ELECTROLESSNICKELCOMPOSITESCOMBINETHEUNIQUEPROPERTIESOFCONVENTIONALELECTROLESSNICKELDEPOSITSSUCHASUNIFORMITYOFDEPOSITIONOVERCOMPLEXGEOMETRIES,HIGHHARDNESSANDGOODCORROSIONRESISTANCEWITHTHATOFABRASIVEMATERIALSPOSSESSINGHIGHTEMPERATURERESISTANCEANDOTHERTRIBIOLOGICALPROPERTIESITISINTERESTINGTONOTETHATINELECTROLESSDEPOSITIONITISPOSSIBLETOACHIEVEAHIGHPERCENTAGEOFINCORPORATIONEVENATLOWCONCENTRATIONSOFPARTICLESINTHEBATH,INCONTRASTTOELECTROPLATING,WHEREALARGECONCENTRATIONOFPARTICLESMUSTBEPRESENTTOGETAHIGHPERCENTAGEOFINCORPORATIONINRECENTYEARS,COMPOSITEMATERIALSHAVEGAINEDIMPORTANCEINENGINEERINGINDUSTRIES,ESPECIALLYFORHIGHTECHNOLOGYAPPLICATIONSSUCHASAEROENGINES,MODERNGASTURBINEENGINES,AUTOMOBILES,ETC6INELECTROLESSCOMPOSITES,THEMATRIXISNOTPURENICKEL,BUTITCANBEEITHERNI–PORNI–B,DEPENDINGUPONTHENATUREOFTHEREDUCINGAGENTSUSEDINTHEBATHTHEMOSTCOMMONLYUSEDHARDDISPERSEDCOMPOUNDSARESIC,DIAMONDPOWDER,ALUMINA,TIC,BNANDWC1–9THELATESTDEVELOPMENTINELECTROLESSCODEPOSITIONISTHEINCORPORATIONOFPOLYTETRAFLUOROETHYLENEPTFEWITHNICKELPTFEPARTICLESAREADDEDTOTHESOLUTIONINTHEFORMOFAWATERDISPERSION10,11THEPROPERTIESOFELECTROLESSNI–PTFECOATINGSSUCHASWEARRESISTANCE,CORROSIONRESISTANCE,FRICTIONCOEFFICIENT,MICROHARDNESSANDALLOTHERPROPERTIESAREEXCELLENT12–18THEPRODUCTION,PROPERTIESANDAPPLICATIONSOFCOMPOSITEELECTROLESSNI/PTFECOATINGSAREGOOD19,20UNIFORMDISPERSIBILITYOFPTFEPARTICLESISOBTAINEDINELECTROLESSNICKELCOMPOSITEPLATING21,22DUNCAN13DEPOSITEDCOATINGSWHICHCONTAIN10–30VOL,03–04MMDIAMETERPARTICLESOFPTFEWITH5–10WTPTHECOEFFICIENTOFFRICTIONISTYPICALLY01–02FORNONLUBRICATEDCONDITIONSITWASALSOFOUNDFROMMICROHARDNESSTESTSANDWEARTESTSTHATTHEHARDNESSOFCOMPOSITECOATINGSWITH14–16PTFEWASTYPICALLY250–400HV,WHILETHEHARDNESSOFTHOSEWITH26PTFEHADONLY275HVAFTERHEATTREATMENTAT300UCHARDNESSVALUESWEREINCREASEDTO625–700HVAND400HV,RESPECTIVELYHADLEYANDHARLAND17DESCRIBEDACOATINGCONTAININGUPTO25WTPTFEUNIFORMLYDISTRIBUTEDINCHEMICALNI–PCONTAINING846NI–7P–84PTFEWTANDWITHASPECIFICGRAVITY65THEYALSOFOUNDTHATHARDNESSDEPENDSONHEATTREATMENTNISHIRAETAL23FOUNDTHATSUSPENSIONOFPTFEPARTICLESINANELECTROLESSNI–PBATHWASAFFECTEDBYNONIONICANDCATIONICSURFACTANTSMATSUDAETAL24FOUNDTHATPTFEPARTICLESWERECODEPOSITEDINELECTROLESSNI–PPLATEDFILMTHISCODEPOSITIONDEPENDSONSURFACTANTTYPE,IEZETAPOTENTIALOFPARTICLESURFACEINTHEPLATINGSOLUTIONANDCONTENTOFPARTICLESINFILMSPTFEHASBEENUSEDASAVERSATILEMATERIALTOPROTECTPARTSFROMCORROSIONANDWEAR25DANIELSANDHARME26FOUNDTHATTHENI–PTFECOATINGINCREASESSERVICELIFEANDPRODUCTQUALITYINPLASTICMANUFACTURE26ZHENGSHANETAL27REPORTEDTHEMORPHOLOGYANDSTRUCTUREOFNI–P–PTFECOATINGSTHISIMPARTSCONSIDERABLENONGALLING,DRYLUBRICANTPROPERTIESTOTHECENTRALELECTROCHEMICALRESEARCHINSTITUTE,KARAIKUDI–630006,TAMILNADU,INDIACORRESPONDINGAUTHOR,EMAILK_N_SRINIVASANYAHOOCOM?2005INSTITUTEOFMATERIALS,MINERALSANDMININGPUBLISHEDBYMANEYONBEHALFOFTHEINSTITUTERECEIVED13SEPTEMBER2004ACCEPTED8NOVEMBER2004156SURFACEENGINEERING2005VOL21NO2DOI101179/174329405X40902DETERMINATIONOFHARDNESSTHECLEANEDMILDSTEELPANELSWEREPLATEDWITHEN/PTFEANDTHEHARDNESSWASMEASUREDUSINGTHEVICKER’SHARDNESSMETHODTHEDIAGONALOFTHEDIAMONDSHAPEDINDENTATIONMADEBYAPPLYINGAKNOWNLOADTHROUGHADIAMONDINDENTORFORADEFINITETIMEWASMEASUREDUSINGAMICROSCOPEFITTEDWITHACALIBRATOREYEPIECETHEVICKER’SHARDNESSWASCALCULATEDFROMTHELENGTHOFTHEDIAGONALDETERMINATIONOFABRASIONRESISTANCEUSINGTABERABRASERTHEEN/PTFEPLATEDSPECIMENWASWEIGHED,THENPLACEDUNDERAPAIROFWEIGHTEDABRADINGWHEELSEACH500GOFCLOSELYCONTROLLEDCOMPOSITIONINSUCHAMANNERASTOCAUSESIDESLIPBETWEENTHEABRADINGWHEELSANDTHESURFACEOFTHETESTSPECIMENTHEWHEELSROTATEDONTHESPECIMENFOR1000REVOLUTIONS,AFTERWHICHTHEPANELWASWEIGHEDAGAINTHEDIFFERENCEINWEIGHTSWASTHEWEARINDEXTABERINDEXORRATEOFWEARTHEEXPERIMENTSWEREREPEATEDTWICE,ANDTHEAVERAGEVALUEWASTAKENTHESAMEEXPERIMENTWASCARRIEDOUTUSINGASPECIMENWHICHWASPLATEDWITHELECTROLESSNICKELONLY,ANDTHEABRASIONRESISTANCEPROPERTIESOFBOTHTHESPECIMENS,WITHANDWITHOUTPTFE,WERECOMPAREDEFFECTOFHEATTREATMENTONHARDNESSTWOSIMILARPANELSWERETAKENONEWASPLATEDWITHNICKELALONEANDTHEOTHERWITHNICKEL/PTFECOMPOSITEBOTHWEREHEATTREATEDAT400UCFOR1HANDTHENTESTEDFORABRASIONRESISTANCEUSINGTHETABERABRASERANALYSISOFNICKELANDPHOSPHOROUSINDEPOSITSTAINLESSSTEELPANELSWEREDEPOSITEDWITHEN/PTFEDEPOSITINVARIOUSCONDITIONSTHEPANELWASETCHEDINCONCENTRATEDHYDROCHLORICACIDFOR1–2MINANDACTIVATEDINPALLADIUMCHLORIDESOLUTIONTHENITWASPLATEDWITHEN/PTFECOMPOSITETHEDEPOSITWASREMOVEDFROMTHEPANEL,WEIGHED,DISSOLVEDIN20MLOF40NITRICACIDANDINCREASEDTO100MLINASTANDARDMEASURINGFLASKNICKELCONTENTINTHESOLUTIONWASANALYSEDVOLUMETRICALLYBYTHEEDTAMETHODANDPHOSPHOROUSBYTHEAMMONIUMPHOSPHOMOLYBDATEMETHODCORROSIONMEASUREMENTSBYPOTENTIOSTATICPOLARISATIONTWOMILDSTEELSAMPLESWERECUTTO75615MM,MECHANICALLYPOLISHED,DEGREASEDWITHTRICHLOROETHYLENEANDETCHEDIN20SULPHURICACIDAT60UCOR2MINONESPECIMENPLATEDWITHNICKELALONEANDTHEOTHERWITHEN/PTFECOMPOSITEFOR2HAT90UCANDPH55POLARISATIONMEASUREMENTSWERECARRIEDOUTPOTENTIOSTATICALLYBYEXPOSINGA1CM2AREAOFEACHPLATEDSPECIMENBOTHWITHANDWITHOUTPTFEUSINGAPOTENTIOSTATPLATINUMWASUSEDASANAUXILLIARYELECTRODEANDASATURATEDCALOMELELECTRODEASTHEREFERENCEELECTRODETHEELECTROLYTEUSEDINTHESTUDYWAS3SODIUMCHLORIDEBOTHANODICANDCATHODICPOLARISATIONSWERECARRIEDOUTAGRAPHWASDRAWNWITHCURRENTDENSITYAGAINSTPOTENTIALUSINGTHETAFELEXTRAPOLATIONMETHOD,THECORROSIONCURRENTANDCORROSIONPOTENTIALSWEREDETERMINEDTHECORROSIONRATEINMILLILITRESPERYEARWASCALCULATEDRESULTSANDDISCUSSIONSEFFECTOFTEMPERATURETHEEFFECTOFTEMPERATUREONTHERATEOFDEPOSITIONISSHOWNINTABLE1THERATEOFDEPOSITIONINCREASESWITHTEMPERATUREANINCREASEINSOLUTIONTEMPERATUREINCREASESTHEFLOWOFTHESOLUTIONTOWARDSTHEELECTRODEBYCONVECTIONBECAUSETHEELECTROLESSPLATINGOFMETALSINVARIABLYINVOLVESAREACTIONPROCEEDINGATARATELIMITEDBYDIFFUSION,INCREASINGTHETEMPERATUREOFTHESOLUTIONFAVOURSMORENICKELIONMOVEMENTTOWARDSTHEELECTRODES,WHICHLEADSTOAHIGHRATEOFDEPOSITIONTHEVOLUMEPERCENTAGEOFPTFECODEPOSITEDWASALSOFOUNDTOINCREASEWITHRISINGTEMPERATUREEFFECTOFDEPOSITIONTIMETABLE2SHOWSTHECHANGEINTHICKNESSOFTHEDEPOSITWITHINCREASEINDEPOSITIONTIMEITWASFOUNDTHAT,ASTHEDEPOSITIONTIMEINCREASES,THETHICKNESSOFTHEDEPOSITALSOINCREASESEFFECTOFCONCENTRATIONOFPTFEINBATHTHEPTFECONTENTINTHEBATHWASVARIEDFROM5GL–1TO20GL–1,ANDTHENICKELANDPHOSPHOROUSCONTENTINTHEDEPOSITSWASANALYSEDTHEANALYSISSHOWEDTHATTHEHYPOPHOSPHITEADDEDTOREDUCENI2ZPRODUCEDAPHOSPHOROUSCONTENTOF8THEAMOUNTOFNICKELINTHEDEPOSITWASFOUNDTODECREASEASTHEPTFECONCENTRATIONINCREASEDTHISCONFIRMSTHATTHEREISANINCREASEINTHEVOLUMEPERCENTAGEOFPTFEWITHANINCREASEINITSCONCENTRATIONTHEVOLUMEPERCENTAGEOFPTFEATTAINEDACONSTANTVALUEFROM15GL–1ONWARDSTHEEFFECTOFCONCENTRATIONOFPTFEISGIVENINTABLE3TABLE1INFLUENCEOFTEMPERATUREOFBATHONRATEOFDEPOSITIONATPH55TEMPERATURE,UCRATEOFDEPOSITION,MMH–160377050808090105TABLE3EFFECTOFCONCENTRATIONOFPTFEINBATHCONCENTRATIONOFPTFE,GL–1PTFEINEN/PTFEDEPOSIT,VOL5180720892261124013248152491725019250TABLE2EFFECTOFPLATINGTIMEONTHICKNESSOFDEPOSITATBATHTEMPERATURE90UCANDPH55THICKNESSOFDEPOSIT,MMTIMEOFDEPOSITION,H10511792259330845381SRINIVASANANDJOHNELECTROLESSNICKEL–PTFECOMPOSITECOATINGS158SURFACEENGINEERING2005VOL21NO2
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簡(jiǎn)介:ELECTRODEPOSITIONOFMIXEDCHROMIUMMETALCARBIDEOXIDECOATINGSFROMATRIVALENTCHROMIUMFORMATEELECTROLYTEWITHOUTABUFFERINGAGENTJHOJWIJENBERGA,,MSTEEGHA,MPAARNTSA,KRLAMMERSA,JMCMOLBATATASTEEL,RESEARCHDEVELOPMENT,IJMUIDENTECHNOLOGYCENTRE,POBOX10000,1970CA,IJMUIDEN,THENETHERLANDSBDELFTUNIVERSITYOFTECHNOLOGY,DEPARTMENTOFMATERIALSSCIENCEANDENGINEERING,MEKELWEG2,2628CDDELFT,THENETHERLANDSARTICLEINFOARTICLEHISTORYRECEIVED19MARCH2015RECEIVEDINREVISEDFORM20MAY2015ACCEPTED21MAY2015AVAILABLEONLINE23MAY2015KEYWORDSELECTRODEPOSITIONTRIVALENTCHROMIUMELECTROLYTICCHROMIUMCOATEDSTEELCURRENTDENSITYMASSFLUXABSTRACTTHEELECTRODEPOSITIONOFMIXEDCHROMIUMMETALCARBIDEOXIDECOATINGSONLOWCARBONMILDSTEELFROMATRIVALENTCHROMIUMFORMATEELECTROLYTEWITHOUTABUFFERINGAGENTISINVESTIGATEDATAROTATINGCYLINDERELECTRODEENABLINGPRECISECONTROLOFTHEMASSFLUXATEQUILIBRIUMCONDITIONS,IEINTHEBULKOFTHEELECTROLYTEWITHPH23,CRIIIMAINLYEXISTSINTHEFORMOFCRHCOOH2O52ADEPOSITIONMECHANISMISPROPOSEDBASEDONAFAST,STEPWISEDEPROTONATIONOFTHEWATERLIGANDSINTHECRIIICOMPLEXIONINDUCEDBYASURFACEPHINCREASEDUETOTHEHYDROGENEVOLUTIONREACTION,WHICHISCONTROLLEDVIATHEAPPLIEDCURRENTDENSITYTHREEDIFFERENTREGIMESCANBEDEFINEDRELATEDTOTHECURRENTDENSITYANDMASSFLUXATLOWCURRENTDENSITIESNODEPOSITISFORMEDONTHEELECTRODE,BECAUSESOLUBLECRHCOOOHH2O4ISFORMEDATTHEELECTRODEREGIMEIABOVEACERTAINTHRESHOLDVALUEOFTHECURRENTDENSITYCRHCOOOH2H2O3ISDEPOSITEDONTHEELECTRODEREGIMEIIAPARTOFTHECRIIIOFTHEDEPOSITISREDUCEDTOCRMETALANDFORMATEISBROKENDOWNLEADINGTOTHEFORMATIONOFCRCARBIDETHEAMOUNTANDCOMPOSITIONOFTHEDEPOSITINREGIMEIISTRONGLYDEPENDONTHEAPPLIEDCURRENTDENSITY,MASSFLUXANDELECTROLYSISTIMEATHIGHCURRENTDENSITIES,AFURTHERSHIFTOFTHEACIDBASEEQUILIBRIUMTOCRHCOOOH3H2O2?RESULTSINADEPOSITONTHEELECTRODETHATISMAINLYCOMPOSEDOFCROXIDEREGIMEIIIINSTARKCONTRASTTOREGIMEII,THEAMOUNTANDCOMPOSITIONOFTHEDEPOSITINREGIMEIIIAREALMOSTINVARIANTOFTHEAPPLIEDCURRENTDENSITY,MASSFLUXANDELECTROLYSISTIME?2015ELSEVIERLTDALLRIGHTSRESERVED1INTRODUCTIONCHROMIUMCOATINGSAREWIDELYUSEDFORMANYDIFFERENTAPPLICATIONS,INCLUDINGELECTROLYTICCHROMIUMCOATEDSTEELECCSFORPACKAGINGAPPLICATIONS1–3ECCSCONSISTSOFATHINGAUGELOWCARBONSTEELSUBSTRATEWITHAVERYTHINCOATINGCOMPRISINGABASELAYEROFCHROMIUMMETAL50–150MGM2ANDATOPLAYEROFCHROMIUMOXIDE7–35MGM2ECCSISPRODUCEDINHIGHSPEEDCONTINUOUSSTEELSTRIPPLATINGLINES,INWHICHANENDLESSSTEELSTRIPOFABOUT1MWIDEISTRANSPORTEDVERYFASTTYPICALLY5MS?1THROUGHONEORMOREPLATINGCELLSTHEFASTMOVEMENTOFTHESTEELSTRIPINDUCESALOTOFTURBULENCERESULTINGINAHIGHMASSTRANSFERRATEOFTHEELECTROACTIVESPECIESAHIGHMASSTRANSFERRATEALLOWSTHEAPPLICATIONOFVERYHIGHCURRENTDENSITIESTYPICALLY,THEDEPOSITIONPROCESSISALREADYCOMPLETEDWITHINAFEWSECONDSECCSISPRODUCEDFROMHEXAVALENTCHROMIUMELECTROLYTESBUTCRVIISNOWADAYSCONSIDEREDAHAZARDOUSSUBSTANCETHATISHARMFULTOTHEENVIRONMENTANDCONSTITUTESARISKINTERMSOFWORKERSAFETYTHEUSEOFCRVIWILLBERESTRICTEDWITHINEUROPEIN2017DUETOREACHLEGISLATION4RESEARCHINTHEPASTDECADESHASFOCUSSEDONTHEDEVELOPMENTOFTRIVALENTCHROMIUMELECTROLYTESSINCECRIIICOMPOUNDSARENOTTOXIC5–19COMMERCIALCRIIIPLATINGPROCESSESFORAPPLYINGDECORATIVECOATINGSHAVEALREADYBEENINUSESINCETHEMID1970S5SUCHELECTROLYTESTYPICALLYCONTAINACOMPLEXINGAGENTEGFORMATE,ACETATE,OXALATE,CITRATEORGLYCINEFORDESTABILISINGTHEVERYSTABLECRDH2OT3T6COMPLEXANDAPHBUFFERUSUALLYBORICACIDFORPREVENTINGHYDROLYSISANDOLATIONREACTIONSBYMINIMISINGTHEPHINCREASENEARTHECATHODEASARESULTOFHYDROGENFORMATION6–8FURTHERDETAILSOFTHEHYDROLYSIS,OLATION,POLYMERISATIONANDCORRESPONDINGAUTHORATTATASTEEL,RESEARCHDEVELOPMENT,IJMUIDENTECHNOLOGYCENTRE,POBOX10000,1970CAIJMUIDEN,THENETHERLANDSTEL310251498714EMAILADDRESSJACQUESWIJENBERGTATASTEELCOMJHOJWIJENBERGHTTP//DXDOIORG/101016/JELECTACTA20150512100134686/?2015ELSEVIERLTDALLRIGHTSRESERVEDELECTROCHIMICAACTA1732015819–826CONTENTSLISTSAVAILABLEATSCIENCEDIRECTELECTROCHIMICAACTAJOURNALHOMEPAGEWWWELSEVIERCOM/LOCATE/ELECTACTATOACYLINDRICALSHAPEANDWELDEDONASOUDRONICAFB1000CANBODYWELDERTHEHEIGHTOFTHECYLINDERSWAS113MMTHELARGESURFACEAREAOFTHESTEELCYLINDERS26DM2FACILITATESSURFACEANALYSISAPLATINISEDTICYLINDERCUSTOMMADEBYMAGNETOSPECIALANODESBVWITHANINNERDIAMETEROF100MMSERVEDASCOUNTERELECTRODETHETHICKNESSOFTHETITANIUMIS2MMANDTHEPLATINUMCOATINGWEIGHTIS50GM?2THEANODEWASSYMMETRICALLYPOSITIONEDWITHRESPECTTOTHESTEELCYLINDERTHEANODEWASPARTIALLYISOLATEDBYMEANSOFAPLASTICINSERTTHEPRIMARYCURRENTDENSITYWASOPTIMISEDSUCHTHATTHELOCALCURRENTDENSITYOVERTHECYLINDERISEXACTLYEQUALTOTHEAPPLIEDCURRENTDENSITYFORALMOSTITSENTIRESURFACEAREAEXCEPTFORBOTHEDGESTHEPRIMARYCURRENTDISTRIBUTIONOVERTHESTEELCYLINDERWASCALCULATEDWITHTHESOFTWAREPACKAGEELSYVERSION61FORCALCULATINGTHEPRIMARYCURRENTDISTRIBUTION,TWODIFFERENTIALEQUATIONSWERESOLVEDNUMERICALLYFORTHISCELLGEOMETRYTHELAPLACEEQUATIONR2F?0ANDOHMSLAWI??KRF,WHEREFISTHEPOTENTIALV,ITHECURRENTDENSITYAM?2ANDKTHEELECTROLYTECONDUCTIVITYSM?1THEACTUALCURRENTDENSITYATTHECENTREOFTHESTEELCYLINDERISEXACTLYEQUALTOTHEAPPLIEDCURRENTDENSITYWHENTHEACTIVEHEIGHTOFTHEANODEIS103MMINFIG1,THEPRIMARYCURRENTDISTRIBUTIONOVERTHESTEELCYLINDERISSHOWNFROMITSCENTREX0TOITSEDGESX05HTHEMAXIMUMROTATIONALSPEEDVOFTHERCEDEVICEISABOUT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下載積分: 10 賞幣
上傳時(shí)間:2024-03-13
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簡(jiǎn)介:SHORTCOMMUNICATIONDOI101002/EJOC201301248OXIDATIVEC–SECOUPLINGOFFORMAMIDESANDDISELENIDESBYUSINGAQUEOUSTERTBUTYLHYDROPEROXIDEACONVENIENTSYNTHESISOFSELENOCARBAMATESPUSHPINDERSINGH,AAANCHALBATRA,APARAMJITSINGH,AAMARJITKAUR,AANDKAMALNAINSINGHAKEYWORDSOXIDATION/COUPLINGREACTIONS/REACTIONMECHANISMS/SELENIUM/C–HACTIVATIONANOXIDATIVECOUPLINGREACTIONBETWEENFORMAMIDESANDDISELENIDESUNDERMETALFREECONDITIONSISDESCRIBEDTHEC–SEBONDFORMATIONOCCURREDEXCLUSIVELYATTHECARBONYLINTRODUCTIONDIRECTC–HFUNCTIONALIZATIONOFHETEROATOMCONTAININGCOMPOUNDSBYCROSSDEHYDROGENATIVECOUPLINGCDCISONEOFTHEMOSTEFFICIENTROUTESFORC–CBONDFORMATIONANDHASBEENUSEDFORTHESYNTHESISOFVERSATILEBUILDINGBLOCKSANDBIOLOGICALLYACTIVENATURALPRODUCTS1THEADVANTAGEOFUSINGNONFUNCTIONALIZEDSUBSTRATESMAKESTHISPROCEDUREMOREEFFECTIVEWITHWIDERAPPLICABILITY2INTHERECENTPAST,SEVERALEFFICIENTMETHODSFORC–HACTIVATIONΑTONITROGENANDOXYGENATOMSHAVEBEENDEVELOPEDUNDERBOTHTRANSITIONMETALEG,CU,FEANDRUCATALYSEDANDMETALFREECONDITIONS3,4MANYREPORTSALSODESCRIBETHEFORMATIONOFC–N,C–P,C–OANDC–SBONDSBYUSINGCDCPROCEDURES5HOWEVER,C–SEBONDFORMATIONBYDIRECTC–HSELENYLATIONHASRECEIVEDVERYLITTLEATTENTIONANDISLIMITEDTOMETALCATALYSEDREACTIONSOFELECTRONRICHARENEORINDOLEC–HBONDSWITHDIARYLSELENIDES6OTHERMETALCATALYSEDREACTIONSOFDISELENIDES,SELENOLSORSELENOHALIDESWITHSUBSTRATESSUCHASALKYLHALIDES,ALKYNES,ORGANOBORANESANDORGANOSILANESHAVEALSOBEENEXPLOREDINTHESYNTHESISOFORGANOSELENIDESOFBIOLOGICALANDPHARMACEUTICALIMPORTANCEANDWITHAPPLICATIONSINMATERIALSSCIENCE7HOWEVER,THEMETALCATALYSEDREACTIONSAREGENERALLYACCOMPANIEDBYTOXICMETALIMPURITIESALONGWITHPHARMACEUTICALLYIMPORTANTFINALPRODUCTS8A–8CANDTHEMECHANISTICPATHWAYSAREUSUALLYCOMPLICATED8DTHUS,FROMTHEPERSPECTIVEOFDEVELOPINGANEFFICIENTANDGREENERMETHODOLOGYBYUSINGSIMPLEREACTIONCONDITIONS,AMETALFREEAPPROACHTODIRECTC–SEBONDFORMATIONWOULDBEANATTRACTIVESTRATEGYADEPARTMENTOFCHEMISTRYANDCENTREOFADVANCEDSTUDIESINCHEMISTRY,PANJABUNIVERSITY,CHANDIGARH160014,INDIAEMAILKNSPUACINHTTP//CHEMISTRYPUCHDACIN/SUPPORTINGINFORMATIONFORTHISARTICLEISAVAILABLEONTHEWWWUNDERHTTP//DXDOIORG/101002/EJOC201301248?2013WILEYVCHVERLAGGMBHCOKGAA,WEINHEIMEURJORGCHEM2013,7688–76927688CARBONBYUSINGAQUEOUSTERTBUTYLHYDROPEROXIDEAND4?MOLECULARSIEVESANDTHECOUPLEDPRODUCTS,SELENOCARBAMATES,WEREOBTAINEDINMODERATETOGOODYIELDSSELENOCARBAMATES,AGROUPOFORGANOSELENIUMCOMPOUNDS,ACTASPRECURSORSFORΑALKYLIDENEΒ/ΔLACTAMSEXHIBITINGANTIBIOTICPROPERTIES9THEANTIVIRALEFFECTSOFCOMPOUNDSCONTAININGTHISFRAMEWORKHAVEALSOBEENSTUDIED10NSUBSTITUTEDSEPHENYLSELENOCARBAMATESAREUSEFULPRECURSORSFORTHEGENERATIONOFCARBAMOYLRADICALSANDOTHERSYNTHETICTRANSFORMATIONS11SELENOCARBAMATESCANBEUSEDASPROTECTEDSELENOLSANDSMOOTHLYDEPROTECTEDUNDERALKALINECONDITIONS12TRADITIONALLY,SELENOCARBAMATESHAVEBEENPREPAREDFROMAROMATICISOCYANATESANDHALOALKANESBYUSINGLIALHSEHASASELENATINGAGENT12BORFROMARYLHALIDESBYLITHIUM/HALOGENEXCHANGEFOLLOWEDBYSELENIUMMETALINSERTIONANDQUENCHINGWITHN,NDIALKYLCARBAMOYLCHLORIDE12B,12CDIMETHYLFORMAMIDEISNORMALLYUSEDASASOLVENT,13BUTISALSOCONSIDEREDASASOURCEOFCO,ME2N,ME2NCOANDOXYGEN14HOWEVER,THEDIRECTC–HACTIVATIONOFFORMAMIDESHASALSOBEENREPORTED15–18INTHESEOXIDATIVEREACTIONS,HYDROGENABSTRACTIONCANOCCURFROMTWODIFFERENTSITESTHEFORMYLC–HORTHEC–HΑTOTHENITROGENATOMTERTBUTYLHYDROPEROXIDETBHP/CUMEDIATEDDIRECTAMIDATIONOFΒKETOESTERSANDΒDICARBONYLPHENOLSWITHFORMAMIDESHASRECENTLYBEENACHIEVEDANDOCCURSATTHEC–HCENTREOFTHEFORMYLMOIETY16THEMETALFREEREACTIONOFFORMAMIDESWITHPHTHALIMIDESANDDECARBOXYLATIVEC–HACYLOXYLATIONOFDMFHAVEBEENREPORTEDTOOCCURREGIOSELECTIVELYATTHEC–HCENTREΑTOTHENITROGENATOM18XIANGANDCOWORKERSREPORTEDTHATINTHEDIRECTOXIDATIVETHIOLATIONOFDMFWITHDIPHENYLDISULFIDE,THEPRODUCTSCORRESPONDINGTOHYDROGENABSTRACTIONFROMTHEFORMYLC–HANDTHEC–HΑTOTHENITROGENATOMAREFORMEDINAPPROXIMATELYEQUALAMOUNTS18AHOWEVER,BYUSINGTHIOPHENOLASACOUPLINGPARTNERALONGWITHCUOAC2/TBHP,THEREGIOSELECTIVEFORMATIONOFTHIOCARBAMATEWASOBSERVED18BITMAYBENOTEDTHATTHEREACTIONOFSIMPLEPHENOLWITHDMFINTHEPRESENCEOFCUCL/TBHPRESULTEDINNOPRODUCTFORMATION16BPSINGH,ABATRA,PSINGH,AKAUR,KNSINGHSHORTCOMMUNICATIONTABLE3STUDYOFTHESUBSTRATESCOPEINTHECOUPLINGREACTIONBETWEENFORMAMIDESANDDESELENIDESAAREACTIONCONDITIONS180EQUIV,21EQUIV,4?MS01G/02MMOL,AQTBHP4EQUIVBISOLATEDYIELDCNOREACTIONWWWEURJOCORG?2013WILEYVCHVERLAGGMBHCOKGAA,WEINHEIMEURJORGCHEM2013,7688–76927690AMIDES,NAMELYN,NDIMETHYL,N,NDIETHYL,N,NDIBUTYLANDN,NDIISOPROPYLFORMAMIDE1A–1D,REACTEDWITHTHEDIARYLDISELENIDESTOGIVETHECOUPLEDPRODUCTSINMODERATETOGOODYIELDSTABLE2DISELENIDESBEARINGELECTRONDONATINGGROUPSONTHEPHENYLRING2B,2CSMOOTHLYAFFORDEDTHECORRESPONDINGCOUPLEDPRODUCTS3E–3LTABLE2,ENTRIES5–12DI1NAPHTHYLDISELENIDE2DALSOGAVETHEPRODUCTS3M–3OINGOODYIELDSTABLE2,ENTRIES13–15HOWEVER,BIS2METHOXY1NAPHTHYLDISELENIDE2EGAVELOWERYIELDSTABLE2,ENTRIES16AND17,WHICHMAYBEDUETOSTERICFACTORSTHEUSEOFDIBENZYLDISELENIDE2FASACOUPLINGPARTNERALSOGAVETHEPRODUCTS3RAND3SINYIELDSOF74AND67,RESPECTIVELYTABLE2,ENTRIES18AND19INADDITION,NOOTHERNEWPRODUCTSWEREDETECTEDINTHESEREACTIONSTOTESTTHEGENERALITYOFTHISPROCEDURE,WEALSOEVALUATEDTHEREACTIONWITHCYCLICFORMAMIDES1E–1GTHECORRESPONDINGSELENOCARBAMATESWEREOBTAINEDINYIELDSOF51–71TABLE3,ENTRIES1–6HOWEVER,NMETHYLFORMAMIDE1HANDNPHENYLFORMAMIDE1IFAILEDTOGIVETHECOUPLEDPRODUCTTABLE3,ENTRIES7AND8INADDITION,N,NDIMETHYLACETAMIDE1JALSOFAILEDTOREACTTABLE3,ENTRY9THEREFOREITCANBEINFERREDTHATTHEPRODUCTCORRESPONDINGTOC–HABSTRACTIONΑTOTHENITROGENATOMISNOTFORMEDEVENWHENFORMYLC–HABSTRACTIONISBLOCKEDITWASPROPOSEDEARLIERTHATTHEREACTIONOFFORMAMIDEWITHDIFFERENTCOUPLINGPARTNERSSUCHASAZOLE,ΒKETOESTERSANDTHIOLINTHEPRESENCEOFOXIDANTSLIKETBHPANDDTBPOCCURSREGIOSELECTIVELYBYFORMYLHYDROGENABSTRACTIONANDPROCEEDSTHROUGHARADICALPATHWAY16–18INTHISCASEALSO,WHENTHERADICALSCAVENGERTEMPO4EQUIVWASADDEDTOTHEREACTIONMIXTUREOF1AAND2AUNDERTHEOPTIMIZEDREACTIONCONDITIONSTABLE1,ENTRY2,THEYIELDOFPRODUCT3AWASREDUCEDDRAMATICALLY7,WHICHSUGGESTSTHEINVOLVEMENTOFARADICALOIDSPECIESTHEREFOREWEHAVEPROPOSEDAPLAUSIBLEMECHANISMFORTHISREACTIONSCHEME2HYDROGENRADICALABSTRACTIONFROMFORMAMIDE1ABYTBHPGIVESINTERMEDIATEA,WHICHREACTSWITHPHSESEPHTOGIVETHECOUPLEDPRODUCT3AANDSELENYLRADICALBTHEINTERMEDIATEBEITHERREACTSWITH1ATOGIVEPHSEHANDINTERMEDIATEAORITDIRECTLYREACTSWITHTHEINITIALLYFORMEDINTERMEDIATEATOGIVETHEDESIREDPRODUCTINTHEPRESENCEOFTBHP,PHSEHISOXIDIZEDTOPHSESEPHTOCOMPLETETHECYCLE20SCHEME2TENTATIVEMECHANISMFORTHECOUPLINGREACTIONBETWEENFORMAMIDESANDDISELENIDES
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簡(jiǎn)介:中文中文2650字文獻(xiàn)出處文獻(xiàn)出處SINGHP,BATRAA,SINGHP,ETALOXIDATIVEC–SECOUPLINGOFFORMAMIDESANDDISELENIDESBYUSINGAQUEOUSTERT‐BUTYLHYDROPEROXIDEACONVENIENTSYNTHESISOFSELENOCARBAMATESJEUROPEANJOURNALOFORGANICCHEMISTRY,2013,20133476887692本科畢業(yè)設(shè)計(jì)本科畢業(yè)設(shè)計(jì)論文論文外文翻譯外文翻譯(201屆)題目題目學(xué)生姓名學(xué)生姓名學(xué)號(hào)指導(dǎo)教師專業(yè)專業(yè)班級(jí)應(yīng)用化學(xué)用化學(xué)專業(yè)專業(yè)班分析化學(xué)模分析化學(xué)模塊所在學(xué)院所在學(xué)院化學(xué)工程學(xué)院化學(xué)工程學(xué)院提交日期提交日期201年3月2二甲基甲酰胺通常被用作溶劑,但也被認(rèn)為是CO、ME2N、ME2NCO和氧氣的原料。然而,直接C–H活化的甲酰胺也有報(bào)道。在這些氧化反應(yīng),氫可以從兩個(gè)不同的位點(diǎn)出現(xiàn)甲酰基的CH和CH––Α的氮原子。Β酮酸酯和Β二羰基酚和甲酰胺在過(guò)氧化叔丁醇(TBHP)/銅介導(dǎo)下酰胺化最近已經(jīng)成功,發(fā)生在甲酰基團(tuán)C–H中心。甲酰胺與鄰苯二甲酰亞胺的無(wú)金屬反應(yīng)和DMF脫羧的酰氧基化反應(yīng)的已經(jīng)被報(bào)道,選擇性發(fā)生在CH與N原子的中心。XIANG和他的同事報(bào)道了DMF和二硫化苯直接氧化硫醇,產(chǎn)品與在甲酰胺CH和Α氮原子之間轉(zhuǎn)移的氫氣的量對(duì)應(yīng)。然而,通過(guò)使用苯硫酚作為一種偶合反應(yīng)的添加物并且伴隨CU(OAC)2/TBHP,可以觀察硫代氨基甲酸酯的選擇性形成??梢灾赋龅氖?,純粹的酚與DMF在CUCL/TBHP的存在下,將不會(huì)產(chǎn)生反應(yīng)。由于持續(xù)關(guān)注促進(jìn)了實(shí)用的新反應(yīng)的發(fā)展,我們研究了甲酰胺和二硒醚之間的是否能發(fā)生氧化偶聯(lián)反應(yīng),用來(lái)形成一個(gè)新的C–SE鍵。此外,這種反應(yīng)的區(qū)域選擇性的將感興趣的不僅對(duì)硫醚的相應(yīng)的反應(yīng),也對(duì)氨基甲酸酯硒感興趣,它可能是其中的一個(gè)產(chǎn)品,具有相當(dāng)?shù)闹匾?。圖1甲酰胺和硒醚的無(wú)金屬耦合反應(yīng)結(jié)果和討論結(jié)果和討論我們最初的研究主要集中在DMF1A)和二苯硒(2A)。80個(gè)當(dāng)量的DMF也當(dāng)做溶劑)和1個(gè)當(dāng)量的2A混合,并加入4?分子篩,反應(yīng)溫度100℃,12小時(shí),在氮?dú)獗Wo(hù)下,并使用4個(gè)當(dāng)量的70TBHP充當(dāng)氧化劑。通過(guò)柱色譜法純化后得到處理,得到收率為27產(chǎn)品3A(表1,條目1)以及未反應(yīng)的2A(45)。通過(guò)薄層色譜分析沒(méi)有發(fā)現(xiàn)其他新產(chǎn)品。提高反應(yīng)溫度120C3A°提高產(chǎn)量的68(表1,條目2)。減少反應(yīng)是時(shí)間將得到更低的
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