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大约在2400年前,古希腊哲学家德谟克利特相信一切都是由微小的粒子组成的.直到19世纪初,英国科学家道尔顿才证明了原子的存在.他认为物质由原子组成,原子不能创造,也不能毁灭且在化学变化中不可再分割,它们在化学反应中保持本性不变.有的分子由单个原子组成,叫做"单原子分子";绝大多数分子都是由多个原子组成的,叫做"多原子分子".1911年英国物理学家卢瑟福通过α粒子散射实验证明,原子中这个带正电荷的部分集中在一起,被称为原子核.在此实验的基础上,卢瑟福提出了带核的原子模型:原子由原子核和核外电子组成,原子核带正电荷,并位于原子中心,电子带负电荷,在原子核周围空间做高速运动,就像行星绕太阳运转一样. 相似文献
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为探究不同隔离套壁厚下磁力驱动泵冷却工作介质流经隔离套工作间隙所产生压力损失对隔离套性能的影响,对隔离套的结构尺寸及隔离套工作间隙变化时冷却循环流道流场特性进行探讨。利用SolidWorks和ANSYS Workbench建立冷却循环流道等比例三维模型,基于SIMPLC算法和RNG κ-ε模型,利用Fluent仿真分析磁力驱动泵冷却流道内部流场特性,计算可得:冷却工作介质进入导流孔后形成漩涡引起局部压力损失;流经隔离套底部进入泵轴中心回流孔处压力损失最大;流经隔离套工作间隙存在压力损失并随隔离套工作间隙的增大而减小,隔离套壁厚为0.8 mm且工作间隙2.6 mm时,压力损失值最小为2 000 Pa,此数据为隔离套的结构优化提供参考。 相似文献
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By utilizing a two-step process to express the charge generation and separation mechanism of the transition metal oxides (TMOs) interconnector layer, a numerical model was proposed for tandem organic light emitting diodes (OLEDs) with a TMOs thin film as the interconnector layer. This model is valid not only for an n-type TMOs interconnector layer, but also for a p-type TMOs interconnector layer. Based on this model, the influences of different carrier injection barriers at the interface of the electrode/organic layer on the charge generation ability of interconnector layers were studied. In addition, the distribution characteristics of carrier concentration, electric field intensity and potential in the device under different carrier injection barriers were studied. The results show that when keeping one carrier injection barrier as a constant while increasing another carrier injection barrier, carri- ers injected into the device were gradually decreased, the carrier generation ability of the interconnector layer was gradually reduced, the electric field intensity at the interface of the organic/electrode was gradually enhanced, and the electric field distribution became nearly linear: the voltage drops in two light units gradually became the same. Meanwhile, the carrier injection ability decreased as another carrier injection barrier increased. The simulation re- sults agree with the experimental data. The obtained results can provide us with a deep understanding of the work mechanism of TMOs-based tandem OLEDs. 相似文献
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