简介:在磷酸钠-磷酸二氢铵-高锰酸钾体系中对镁合金进行化学转化处理.研究了磷酸钠、磷酸二氢铵、高锰酸钾、温度、时间和添加剂对转化膜性能的影响.通过对转化膜结构、成分及性能的测试评价,得到了性能较好的化学转化溶液配方:Na3PO4为5g·L^-1,NH4H2PO4为15g·L^-1,KMnO4为1g·L^-1,添加剂(NH4)5Mo7O24为0.5g·L^-1.由SEM可观察到转化膜的表面成“干枯河床”状.XRD和EDS检测表明,膜层的主要成分是Mg,Al12Mg17和无定形相,膜层表面主要有Mn,Mg,K,O和Al等元素组成.腐蚀实验和电化学测试表明,添加剂能够降低转化膜的腐蚀率,转化膜较基体的腐蚀电位正移了0.73V,提高了镁合金的耐蚀性.
简介:主要考虑1+1维Boussinesq系统的一个Darboux变换,反复利用该Darboux变换,可以从该系统的一个已知解出发,通过代数运算和求导运算得到系统的新解.
简介:Aseriesofnovel1H-benzimidazol-1-ylacetatesand1H-benzimidazol-1-ylpropionatescontaining1H-1,2,4-triazolemoietyweresynthesizedundermicrowaveirradiationbymulti-stepreactions,inyieldsof87-94%.TheirinvitroantifungalactivitiesagainstBotrytiscinereaandSclerotiniasclerotiorumwereevaluatedbymycelialgrowthratemethod.AllthetargetcompoundsexhibithighactivitiesagainstB.cinereawiththeEC50valuesof7.96-21.74μg/mL,higherthanthatofcarbendazim.
简介:WeuseamodifiedBecke-JohnsonexchangeplusalocaldensityapproximationcorrelationpotentialwithinthedensityfunctionaltheorytoinvestigatetheelectronicstructuresofHg1-xCdxTeandIn1-xGaxAswithxbeing0,0.25,0.5,0.75,and1.Forbothofthetwoseries,ourcalculatedenergygapsanddielectricfunctions(realpartε1andimaginarypartε2)areinagreementwiththecorrespondingexperimentalresultswithxbeingbetween0and1.Thecalculatedzero-frequencyrefractiveindexvariesgreatlywithxforHg1-xCdxTe,butchangeslittlewithxforIn1-xGaxAs,whichisconsistentwiththerealpartsoftheirdielectricfunctions.Therefore,thisnewapproachissatisfactorytodescribetheelectronicstructuresandtheopticalpropertiesofthesemiconductors.
简介:这份报纸为1-D板方程wtt+wxxxx+q处理锋利的observability不平等的问题(t,x)0边界与二打的w=调节w=wxx=0或w=wx=0,并且q(t,x)是一个合适的潜力。锋利的observability常数具有的作者表演订$\exp\left({C\left\|q\right\|_\infty^{\tfrac{2}{7}}}\right)$\exp\left({C\left\|q\right\|_\infty^{\tfrac{2}{7}}}\right)为q1。导出需要的observability不平等的主要工具是全球Carleman不平等,基于一个新点为第四个顺序板操作员的明智的不平等。
简介:Inthispaperwewillshowthatifanapproximationprocess{Ln}n∈Nisshapepreservingrelativetotheconeofallk-timesdifferentiablefunctionswithnon-negativek-thderivativeon[0,1],andtheoperatorsLnareassumedtobeoffiniterankn,thentheorderofconvergenceofDkLnftoDkfcannotbebetterthann2evenforthefunctionsxk,xk+1,xk+2onanysubsetof[0,1]withpositivemeasure.Takingintoaccountthisfact,wewillbeabletofindsomeasymptoticestimatesoflinearrelativen-widthofsetsofdifferentiablefunctionsinthespaceLp[0,1],p∈N.
简介:在Tikhonov正则化方法的基础上将其转化为一类l1极小化问题进行求解,并基于Bregman迭代正则化构建了Bregman迭代算法,实现了l1极小化问题的快速求解.数值实验结果表明,Bregman迭代算法在快速求解算子方程的同时,有着比最小二乘法和Tikhonov正则化方法更高的求解精度.
简介:BasedontheGrammianandPfaffianderivativeformulae,GrammianandPfaffiansolutionsareobtainedfora(3+1)-dimensionalgeneralizedshallowwaterequationintheHirotabilinearform.Moreover,aPfaffianextensionismadefortheequationbymeansofthePfaffianizationprocedure,theWronski-typeandGramm-typePfaffiansolutionsoftheresultingcoupledsystemarepresented.