排序方式: 共有13条查询结果,搜索用时 15 毫秒
1.
Based on the modeling of dynamics and energy conversion in competitive swimming,the optimal control theory was used to make an optimization analysis of the distance traveled in a given time.Using the records of the 27th Olympics and the results from previous research,an optimal solution of propulsion was derived using some hypotheses and constraints.Correspondingly,the optimal tactic for velocity and energy was put forward which was in agreement with the practice. 相似文献
2.
衬底温度对直流磁控溅射法制备掺锆氧化锌透明导电薄膜性能的影响(英文) 总被引:2,自引:2,他引:0
利用直流磁控溅射法在石英衬底上制备出了高透明导电的掺锆氧化锌(ZnO:Zr)薄膜。研究了衬底温度对ZnO:Zr薄膜结构、形貌及光电性能的影响。XRD表明实验中制备的ZnO:Zr为六方纤锌矿结构的多晶薄膜,具有垂直于衬底方向的c轴择优取向。实验所制备ZnO:Zr薄膜的晶化程度和导电性能对衬底温度有很强的依赖性。当衬底温度为300℃时,ZnO:Zr薄膜具有最小电阻率7.58×10-4Ω.cm,其可见光平均透过率超过了91%。 相似文献
3.
We have synthesized core/shell structure ZnO composite nanoparticles by surface chemical modification. This new composite material shows a large optical gap redshift compared with the homogeneous ZnO nanoparticles. The visible photoluminescence ranging from blue to red in color with fast decay time may be as signed to the interfacial bound-exciton-like emission. 相似文献
4.
5.
本介绍了基于混合物理化学气相沉积法(HPCVD),以B2H6为硼源,在(000l)取向的Al2O3单晶衬底上,制备了MgB2超导体厚膜样品.该样品平均厚度约为40μm.其Tc(onset)=39K,Tc(0)=37.2K.X光衍射图显示该膜沿(101)方向生长,具有少量Mg和MgO杂相.SEM图像、X射线能量损失谱以及背散射电子衍射图证实了这两种杂相的存在,并显示该样品成分富镁.样品表面的镁与空气接触形成MgO膜,在一定程度上阻止了MgB2样品进一步被氧化.对于MgB2厚膜成膜过程及反应机理,我们提出了一种新的推断. 相似文献
6.
7.
对巨磁电阻锰氧化物材料La2/3Ca1/3MnO3/YSZ(钇稳定氧化锆)(LCMO/YSZ)系列样品低温下电阻率行为进行研究,低温下电阻率行为一般是ρ=ρ0 ATa BTb的形式,其中ρ0为剩余电阻率,a=2或3/2,b=5或9/2.T2代表电子-电子散射项,T3/2代表被无序自旋玻璃散射的电子项,T6代表电子.声子散射项,Tθ/2们代表电子-双磁子散射项.在此指出b=5是合理的,代表电子-声子散射项. 相似文献
8.
9.
研究了铕(Ⅲ)与噻吩甲酰三氟丙酮(HTTA)、丙烯酸(HAA)的三元配合物及与甲基丙烯酸甲酯(MMA)成键聚合物(CPEu(TTA)2AA)和掺杂型聚合物(Eu(TTA)2AA/PMMA)的发光性质.测量了配合物中Eu3+的5D0和5D1能级的荧光衰减,对其传能过程和荧光寿命进行了讨论.测量了配合物及聚合物THF溶液的荧光光谱.配合物和聚合物的吸收峰较配体发生明显红移,且存在配体到中心离子的传能.指出小分子配合物和掺杂型聚合物中Eu3+具有类似的发光性质而与成键型聚合物不同 相似文献
10.
Sorption and permeation of gaseous molecules in amorphous and crystalline PPX C membranes: molecular dynamics and grand canonical Monte Carlo simulation studies 下载免费PDF全文
Amorphous and crystalline poly (chloro-p-xylylene) (PPX C) membranes are constructed by using a novel computational technique, that is, a combined method of NVT+NPT-molecular dynamics (MD) and gradually reducing the size (GRS) methods. The related free volumes are defined as homology clusters. Then the sorption and the permeation of gases in PPX C polymers are studied using grand canonical Monte Carlo (GCMC) and NVT-MD methods. The results show that the crystalline PPX C membranes provide smaller free volumes for absorbing or transferring gases relative to the amorphous PPX C area. The gas sorption in PPX C membranes mainly belongs to the physical one, and H bonds can appear obviously in the amorphous area. By cluster analyzing on the mean square displacement of gases, we find that gases walk along the x axis in the crystalline area and walk randomly in the amorphous area. The calculated permeability coefficients are close to the experimental data. 相似文献