赫巍
,
何松波
,
孙承林
,
吴凯凯
,
王连弟
,
余正坤
催化学报
doi:10.3724/SP.J.1088.2012.11105
基于借氢策略、醇为烷基化试剂的胺的N-烷基化反应是合成胺类化合物的绿色途径.在无外加氢源条件下,多相双金属Pt-Sn/γ-Al2O3催化剂可高效催化醇为烷基化试剂的伯(仲)胺的N-烷基化反应合成仲(叔)胺,反应副产物为水与极少量亚胺.催化体系的底物适应性好,目标产物收率高；催化剂可以循环使用,具有潜在的工业化应用前景.
关键词:
铂
,
锡
,
氧化铝
,
负载型催化剂
,
借氢策略
,
多相催化
,
N-烷基化
,
胺
,
醇
王连弟
,
吴小伟
,
赫巍
,
刘子双
,
余正坤
催化学报
doi:10.3724/SP.J.1088.2010.00456
以1,3-丁二烯、CO和甲醇为原料,进行羧酯化反应合成3-戊烯酸甲酯是Altam路线生产己内酰胺绿色工艺的关键步骤.将Pd与三齿N-杂环配体或双膦配体组成的催化体系用于1,3-丁二烯的羧酯化反应中,其中乙酸钯/2,6-二(3,5-二甲基吡唑基)吡啶催化剂表现出中等的催化活性,在150℃,p(CO)=6.0MPa的优化条件下反应6h,1,3-丁二烯转化率为78.8%,3-戊烯酸甲酯选择性达92.2%(TON=226);而乙酸钯/2,2'-二(二苯基瞵基)苯醚催化体系的活性更高,在优化反应条件下,1,3-丁二烯转化率达90.4%,3-戊烯酸甲酯选择性为91.6%(TON=181).在200℃及类似的羧酯化反应条件下,1,3-丁二烯发生二聚反应,其转化率为99%以上,二聚产物4-乙烯基-1-环己烯选择性高于96%.
关键词:
1,3-丁二烯
,
钯
,
三齿N-杂环配体
,
羧酯化
,
3-戊烯酸甲酯
,
己内酰胺
,
双瞵配体
潘晓光
,
王芳
,
李冲
黄金
doi:10.11792/hj20130510
陡帮开采是加陡露天矿剥岩工作帮所采用的工艺方法、技术措施和采剥程序的总称.鉴于毕力赫金矿区Ⅱ号矿带开采基建及初期岩石剥离量偏大,基建投资及前期生产成本较高,结合Ⅱ号矿带矿体赋存特点及地形条件,设计采用了陡帮开采工艺.分析了陡帮开采的合理性,介绍了陡帮开采工艺参数及实施要点.工程实践表明,毕力赫金矿区陡帮开采,加快了露天采场台阶下降速度,减少了基建初期剥岩量,为及早见矿,保证苏尼特矿业公司即时经济和总体经济效益发挥了重要作用.
关键词:
陡帮开采
,
组合台阶
,
工作帮坡角
,
剥采比
工程热物理学报
根据《吴仲华奖励基金章程》（吴奖[2008]01号），经各高等院校、中国工程热物理学会和中国科学院工程热物理研究所认真评选和推荐，吴仲华奖励基金理事会评审并确定授予青年学者戴巍、罗坤、唐桂华“吴仲华优秀青年学者奖”，授予程雪涛等10位同学“吴仲华优秀学生奖”。
关键词:
基金
,
奖励
,
评选
,
获奖者
,
中国科学院
,
青年学者
,
物理研究所
,
高等院校
周利民
,
廖霞俐
,
许可
,
陈家林
,
陈立桥
,
李俊鹏
贵金属
Rh催化的[5+2]反应是一类高效快速构筑多官能团化七元环的重要方法。介绍了常用的Rh催化剂及其配体；分别基于乙烯基环丙烷(VCP)和劳腾施特劳赫中间体类型的Rh催化[5+2]反应；Rh催化的[5+2]反应机理；Rh催化的[5+2]反应在复杂天然产物合成中的应用。
关键词:
催化化学
,
Rh催化
,
5+2反应
,
有机合成
金属学报(英文版)
桑危郑牛樱裕桑牵粒裕桑希巍。希啤。龋伲模遥希牵牛巍。桑危模眨茫牛摹。模眨茫裕桑蹋拧。拢遥桑裕裕蹋拧。裕遥粒危樱桑裕桑希巍。桑巍。罚保罚怠。粒蹋眨停桑危眨汀。粒蹋蹋希?##2##3##4##5INVESTIGATIONOFHYDROGENINDUCEDDUCTILEBRITTLETRANSITIONIN7175ALUMINUMALLOY$R.G.Seng:B.JZhong,MG.ZengandP.Geng(DepartmentofMaterialsScierce,ScienceCollege,NorthearsternUniveisity,Shenyang110006,ChinaMaruscriptreceived4September1995inrevisedform20April1996)Abstrac:Effectsofhydrogenonthemechanicalpropertiesofdifferentlyaged7175aluminumalloyswereinvestigatedbyusingcathodicH-permeation,slowstrainratetensionandsoon.Theresultsindicatethatboththeyieldstressandthepercentagereductionofareadecreasewithincreasinghydrogenchargingtime,andthedegreeofreductiondecreasesasagingtimeincreasesforthesamehydrogenchargingtime.Keywords:hydrogeninducedductile-brittletransition,7175aluminumalloy,mechanicalproperty,cathodicH-permeation1.IntroductionForalongtimehydrogenembrittlementproblemwasthoughttobeabsentinhighstrengthaluminiumalloybecausethesolutiondegreeofhydrogeninaluminumatcommontemperatureandpressureisverysmall.However,hydrogenembrittlementphenomenonwasfoundinaluminumalloyduringtheinvestigationofstresscorrosionandcorrosionfatigue[1-5].Therehavebeenonlyafewreportsofhydrogeninducedsofteningandhardening.Inthispaper,theeffectsofhydrogenonmechanicalpropertiesof7175aluminumalloywereinvestigatedbyusingcathodicalchargingwithhydrogenandslowtensiontests.2.ExperimentalProcedureTheexperimentalmaterialwas7175aluminumalloyforgingintheformofa43mminthicknessandwithcomposition(wt%).5.41Zn,2.54Mg.1.49Cu,0.22Cr,0.1Mn.0.1Ti,0.16Fe.0.11Si,balancedbyA1.Alloyplateof1.5mminthicknesswasobtainedbyhot(465℃)andtoldrollingto83%reductioninthickness.Thelongaxisofhydrogenchargedspecimensisalongtherollingdirection.Allspecimensweresolidsolutionedat480℃for70min,followedtyimmediatequenchinginwaterandthenagedat140℃for6h(A),16h(B)and98h(C).Thetreatmentof6hiscorrespondingtotheunderagedstate.16hthefirstpeak-agedstateand98hthesecondpeak-agedstate.Thespecimenswerepolishedsuccessivelyusingemerypaperbeforehydrogencharging.Thetensilespecimenswerecathodicallychargedina2NH_2SO_4solutionwithasmallamountofAs_2O_3forpromotinghydrogenabsorption,andwithacurrentdensityof20±1mA/cm￣2atroomtemperature.ThehydrogencontentanalysiswascarriedoutonanLT-1Amodelionmassmicroprobeafterthesputteringdepthreached8nm.Theioncurrentsofhydrogenandaluminuminvariousagedstateswererecordedunderthesamecondition.ThetensiletestswereperformedonanAG-10TAmodeltestmachinewhichwascontrolledbycomputer.3.ExperimentalResultsTheratioofioncurrentstrengthofhydrogentoaluminumisrelatedtohydrogenconcentrationinhydrogenchargedspecimen.TheresultswereshowninTable1Thehydrogencontentincreaseswiththeincreaseincharingtime.Ofthethreeagedstates,theunderagedspecimenhasthehighesthydrogencontent.Theratioofyieldstrengthofhydrogenchargedandunchargedspecimenschangeswithhydrogenchargingtime,asshowninFig.1Itcanbeseenthattheyieldstrengthofhydrogenchargedspecimendecreasewithincreasinghydrogenchargingtime.Atthesamechargingtime,theyieldstressdecreasestheleastinthesecondpeak-agedstate,anddecreasesthemostintheunderagedstate.Itindicatesthattheunderagedspecimenismostsensitivetohydrogeninducedsoftening,whichisconsistentwiththeresultsofanotherhighstrengthaluminumalloy[6].TherelativechangesoftheradioofreductionofareawithhydrogenchargingtimearesummarizedinFig.2,whereΨ￣0andΨ￣Harethepercentagereductionofareaofthesamplewithoutandwithhydrogenchargingrespectively.Theradioofreductionofareareduceswhenhydrogenchargingtimeincreases,andthedecreasingdegreeofreductionofareaincreaseswithincreasingagingtime,ie,,theunderagedstateisthemostsensitivetohydrogenembrittlement.4.DiscussionItisknownfromtheresultsabovethatcathodicalchargingwithhydrogenleadstotheobviousdecreaseinthetensilestrengthandplasticityThisisbecausealargeamountofsolidsolutionhydrogenentersthespecimenintheprocessofhydrogenchargingSolidsolutionhydrogenisliabletoenterthecentreofdislocationundertheactionofdislocationtrap,henceraisingthemovabilityofdislocation.Thereforethedislocationsinhydrogenchargedspecimenmoveeasierthaninunchargedspecimen.soresultinginthereductionofyieldstrength[7].Whendislocationstartstomove,thecrystallatticeresistance(P-Nforce)whichitmustovercomeisgivenby:whereμismodulusofshear,visPoissonratio,aisspanofslipplane,bisatomspanofslipdirection.Moreover.theotherresistanceofdislocationmotionmayarisefromtheelasticinteractionofdislocation,theactionwithtreedislocationandetc.,itcanbeexpressedasfollows:whereαisconstant,XisdislocationspanSotheresistanceofdislocationmotioncanbewrittenasfollows:Becausehydrogenatomsreducetheatombondingstrengthafterhydrogencharging,shearmodulusμdecreasesandresultsinthereductionoff,therebytheyieldstressdecreases.Asthecentreofdislocationistheseriousdistortionzoneoflattice.thestresscanberelaxedafterhydrogenatomstuffing,andthesystemenergydecreases.Thusthecentreofdislocationisastrongtrapofhydrogen[8].Therefore,amovabledislocationcaptureshydrogenandmigratestograinboundaries.phaseboundariesorsurfaceofthespecimen,promotingthecrackiesformationandgrowth,thuscausingthelossofplasticity.Sincethelocalenrichmentofhydrogenisrealizedbydislocationtransporting(inthestageofdeformation),thelargerthereductionofyieldstress.theearlierarehydrogenatomstransportedtotheplaceofenrichment.Inaddition,thedamageofatombondingstrengthinducedbyhydrogenmakesthefracturestressdecrease[9]:whereCHishydrogenconcentration.σ_thisfracturestrengthbeforehydrogenchargingandisfracturestrengthafterhydrogencharging.Eq.(4)showsthatthematerialsmaybefracturedatalowerstraini.e.,brittlefractureoccurs.5.Conclusions(1)Hydrogencontentofdifferentlyagedspecimensincreaseswithincreasinghydrogenchargingtimethecapabilityofthealloytoabsorbhydrogeninunderagedstateisthestrongest.(2)Theyieldstressaswellasthepercentagereductionofareaof7175aluminumalloydecreaseashydrogenchargingtimeincreasesundervariousagedstates.(3)Underagedstateismostsensitivetohydrogeninducedsofteningandhardening.(4)Anexplanationwasofferedforthephenomenonofhydrogeninducedsofteninginthestageofdeformation,andhardeninginthestageoffracture.REFERENCES｜｜1G.KKock,Corrosion35(1979)73.2M.K.TsengandH.LMarcus,Scr.Metall.15(1981)427.3PSFao.M.GaoandR.P.Wei,Scr.Metall.19(1985)265.4R.G.SongandM.K.TsengJ.NortheasternUniversity15(1994)5(inChinese).5R.K.Viswanadham,T.S.sunandJ.A.S.Green,Metall.Trans.11A(1980)85.6J.Liu,M.KTsengandB.R.Liu.NonferrousMiningandMetallrgy5(1989)33(inChinese).7LChen,WXChen,ZHLiuandZ.Q.Hu,InFrocofthe1stNationalConfonAl-LiAlloys(Sheryang.China,1991)p.328(inChinese).8Z.HLiuL.ChenW.XChenY.X.ShaoandZ.Q.Hu,InProc.ofthe1stNationalConfonAl-LiAlloys(Shenyang,China,1991)p.334(inChinese).9R.A.OrianiandF.H.Josephic,ActaMetall.22(1974)1065.##61G.KKock,Corrosion35(1979)73.2M.K.TsengandH.LMarcus,Scr.Metall.15(1981)427.3PSFao.M.GaoandR.P.Wei,Scr.Metall.19(1985)265.4R.G.SongandM.K.TsengJ.NortheasternUniversity15(1994)5(inChinese).5R.K.Viswanadham,T.S.sunandJ.A.S.Green,Metall.Trans.11A(1980)85.6J.Liu,M.KTsengandB.R.Liu.NonferrousMiningandMetallrgy5(1989)33(inChinese).7LChen,WXChen,ZHLiuandZ.Q.Hu,InFrocofthe1stNationalConfonAl-LiAlloys(Sheryang.China,1991)p.328(inChinese).8Z.HLiuL.ChenW.XChenY.X.ShaoandZ.Q.Hu,InProc.ofthe1stNationalConfonAl-LiAlloys(Shenyang,China,1991)p.334(inChinese).9R.A.OrianiandF.H.Josephic,ActaMetall.22(1974)1065.##A##BINVESTIGATION OF HYDROGEN INDUCED DUCTILE BRITTLE TRANSITION IN 7175 ALUMINUM ALLOY$$$$R.G.Seng: B.J Zhong, MG. Zeng and P. Geng(Department of Materials Scierce, Science College,Northearstern Univeisity, Shenyang 110006, China Maruscript received 4 September 1995 in revised form 20 April 1996)Abstrac:Effects of hydrogen on the mechanical properties of differently aged 7175 aluminum alloys were investigated by using cathodic H-permeation, slow strain rate tension and so on. The results indicate that both the yield stress and the percentage reduction of area decrease with increasing hydrogen charging time, and the degree of reduction decreases as aging time increases for the same hydrogen charging time.
关键词:
:hydrogen induced ductile-brittle transition
,
null
,
null
,
null
刘玉
,
焦兰英
钢铁
利用集中度(CRn)和赫芬达尔指数(HI)计算公式,对国内外钢铁工业几十年来的大量数据进行分析研究,定量分析我国钢铁工业集中度现状,指出在我国年产钢量占世界年产钢量比率快速上升、世界钢铁工业集中度连年上升的情况下,我国钢铁工业集中度在下降,而且有下降加速的趋势,指出我国钢铁工业集中度亟待提高.
关键词:
钢铁工业
,
集中度
陈兴宇
,
张为军
,
堵永国
,
胡君遂
,
郑晓慧
,
芦玉峰
硅酸盐通报
采用硼硅酸盐玻璃与氧化铝复合烧结制备了硼硅酸盐玻璃/Al2O3系低温共烧陶瓷基板材料,研究了玻璃含量以及玻璃中碱金属离子的含量对介电性能的影响.结果表明,该体系复合材料介电常数随碱金属离子的增加有所增大,复合材料介电常数符合李赫德涅凯对数法则,并随复合材料玻璃含量的增加而减小;复合材料介质损耗随碱金属离子的增加而显著增大.
关键词:
低温共烧陶瓷
,
硼硅酸盐玻璃/Al2O3
,
介电常数
,
介质损耗
樊新民
,
葛盛健
表面技术
doi:10.3969/j.issn.1001-3660.2004.05.027
为了提高硅钢的低频磁屏蔽效能,在硅钢上电镀了Ni、Ni-P、Ni-Fe合金镀层,用金相法检测了镀层的厚度,用X射线能谱分析了镀层的化学成分,用赫姆霍兹线圈方法测试了低频磁屏蔽效能.结果表明在硅钢上镀Ni,使屏蔽效能降低,镀Ni-P合金使屏蔽性能略有改善,镀Ni-Fe合金后经过热处理后能够显著改善低频磁屏蔽效能.
关键词:
磁屏蔽
,
镀镍
,
镀合金
,
镍镀层
,
合金镀层
