简介:Anovelclassoffulgimide,(Z)-4-oxazolylfulgimide((Z)-1-benzyl-4-isopropylidene-3-[1-(2-aryl-5-methyloxazolyl)ethylidene]tetrahydropyrrole-2,5-dione),wassynthesizedbythereactionof(Z)-4-oxazolylfulgide(4-isopropylidene-3-[1-(2-aryl-5-methyloxazolyl)ethylidene]tetrahydrofuran-2,5-dione)withbenzylamine.Photochromicpropertyof(Z)-4-oxazolylfulgimidewasstudied.Comparedwith(Z)-4-oxazolylfulgide,theabsorptionmaximumofthecoloredformof(Z)-4-oxazolylfulgimideisbathochromic-shifted.Substituentsonthearylringaffecttheabsorptionmaximumoftheopenformandthecoloredformof(Z)-4-oxazolylfulgimide.
简介:传统Z源并网风力发电系统整流侧采用的是三相不可控整流,其定子侧的电流谐波不仅会增大电机的铜耗和铁耗,降低发电效率,还有可能出现电机饱和以及失控等现象,严重影响了系统的稳定性。本文将VIENNA整流器应用于Z源并网风力发电系统,提出一种新的并网变流器控制方法。将定子输出电压的一个周期划分为6个扇区,通过扇区决策控制器给每个扇区内的不导通相提供电流通路,改善了机侧电流与机侧电压的非线性关系。比较了采用三相不可控整流器和VIENNA整流器以及最大升压控制和改进SVPWM控制下Z源并网风力发电系统的机侧电流谐波。仿真与实验结果表明,本文方法减少了定子侧电流谐波,提高了系统的效率和稳定性。
简介:AdynamicalLangevinmodelisemployedtoevaluatetheexcessoftheneutronemissioninthefissionofheavynuclei~(240)Cf,~(246)Cf,~(254)Cf,~(240)Urelativetothestandardstatistical-modelpredictionatvarioussaddle-to-scissionfrictionstrengths.Itisshownthatwhentheneutron-to-protonratioN/Zofthesystemincreases,thesensitivityoftheexcesstothefrictiondecreasessubstantially,anditalmostdisappearsfor~(240)U.WesuggestthatusingthosecompoundsystemswithlowN/Zfavorsanaccuratedeterminationforthesaddle-to-scissionfrictionstrengthbasedonthemeasurementofthepre-scissionneutronmultiplicity.
简介:摘要:热风温度CPK是评价叶丝干燥工序生产批次的过程能力,能否满足产品质量标准要求。据统计,2021年四季度,什邡卷烟厂制丝车间叶丝干燥工序近3个月热风温度不合格(CPK<1)次数达13次,不合格率占比为2.7%。且根据四川中烟《卷烟制丝过程质量检验与判定》为B类异常,严重影响生产质量。本文从减少加热器进风口表面粉尘附着和车间内温湿度变化、减小疏水阀泄压等方面进行优化,有效提高了烘丝机滚筒热风温度CPK,为卷烟产品质量提供了支撑。