简介:采用粉末冶金方法制备高强高导铜合金基纳米复合材料(CuZr/AlN)。采用光学显微镜(OM)和高分辨率透射电镜(HRTEM)等方法研究不同烧结工艺对复合材料组织与性能的影响,研究固溶时效对CuZr/AlN力学性能的影响。结果表明:试样的组织致密,晶粒大小在0.2μm左右;试样的布氏硬度随着复压制压力和烧结温度的升高而升高;试样的布氏硬度开始随着锆含量的增加而升高,但当锆颗粒含量大于0.5%时,复合材料的布氏硬度开始降低。试样的抗弯强度随着复压制压力和烧结温度的升高而提高,抗弯强度在锆含量为在0.5%时最大。900°C固溶后的布氏硬度比固溶前的布氏硬度低,试样在500°C和600°C时效后,布氏硬度增加,在700°C发生过时效现象。
简介:听力训练1Text1W:Isyourcoffeehot,too?M:No,mineisrathercold.Text2W:Iwasexpectingsunshinetoday.M:Yeah,butit’srainingheavilyoutsidenow.Text3W:Dad,doyouknowwherethebasketballis?M:It’sbehindthedoor.Text4W:Pleasegivemethatpencilundertheredbook.
简介:<正>"TheScientificOutlookonDevelopmentwascreatedbyintegratingMarxismwiththerealityofcontemporaryChinaandwiththeunderlyingfeaturesofourtimes,anditfullyembodiestheMarxistworldviewonandmethodologyfordevelopment.ThistheoryprovidesnewscientificanswerstothemajorquestionsofwhatkindofdevelopmentChinashouldachieveinanewenvironmentandhowthecountryshould
简介:IsawhimshakinghischangeinacoffeecupAskedforadollarbutItoldthemantogiveitupSaidhe'shungryIdon'tthinkthatit'strueIbetmydollarhe'llgospenditonboozeIturnedmybackonhimandbegantowalkawayButthenIheardthelittlevoiceinsidemesayWhatifit'sreallytrue,whatifhe'shungry