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CdS, CdS:Mn, ZnS, ZnS:Mn and ZnS:Tb nanoparticles were prepared by using carboxylic-containing copolymer, polystyrene-maleic anhydride (PSM), as template. Average particle size, 2.5 nm for CdS nanoparticles, is deduced from UV-vis absorption spectra and consistent with the observation of TEM. Characteristic emissions of the doping ions can be observed and the energy transfer from the host to the doping ions is verified. Fourier transform infrared (FTIR) spectra were studied to confirm the bonding effect of the copolymer and the metal ions. PSM hydrolyzed and chelated metal ions by its carboxylic group, and then performed as a protection layer after the formation of nanoparticles. 相似文献
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交通流随机行为的研究对于理解交通系统的内在演化规律具有重要作用. 基于元胞自动机模型和顾前势模型, 提出了一种考虑加权顾前势的交通流模型. 通过引入顾前势加权系数及对越靠近自身车辆的相互作用势赋予越大的权重, 使得建模过程更符合实际交通中司机根据前面车辆和环境情况进行随机决策的过程. 通过数值模拟, 再现了丰富的高密度交通行为. 仿真结果表明, 加权系数在高密度情况下作用明显, 更有利于在保持较高交通密度的同时, 具有较高的交通流量和道路通行能力.
关键词:
交通流
顾前势
随机模型
加权 相似文献
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用控制变量法探究决定安培力(F=BIL)大小的因素时,有的用串联不同节数的干电池来研究电流这个因素,结果发现效果总不佳(对比度低),下面分析其原因. 相似文献
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The diluted magnetic semiconductor (DMS), which exploits both the spin and the charge of car- riers, is one of the most important materials to re- alize semiconductor spintronies.Many research works have been focused on the magnetic properties of Mn-doped ZnO due to its room-temperature ferro- magnetism (RT-FM), which is very important for commercial applications. Recently, Mn-doped ZnO nanostruetures were developed for the nano spintronic devices, and kinds of Mn-doped ZnO nanostrue- tures have been prepared with room-temperature fer- romagnetic behavior, while conflicting arguments produced no consensus on the origin of RT-FM in these systems. Vinod et al. reported that the RT-FM in 5 wt% Mn-doped ZnO nanorods is attributed to the increase in the specific area of grain boundaries and the interaction between Mn2+ ions and Zn2+ ions.Yihnaz et al. found that bound magnetic polarons are responsible to the RT-FM. Gao et al. reported that the exchange interaction between the donor electron trapped by the singly ionized oxygen vacancy and sur- rounding Mn ions is responsible for the RT-FM. It was also reported that the ferromagnetism of the Mn-doped ZnO nanowires could be controlled by the electric-field or Mn doping levels. This work will investigate the magnetic property of the Mn-doped ZnO nanowires grown by the chemical vapor deposi- tion (CVD) method under the air condition and under the vacuum condition, respectively, and it is found that crystalline quality plays an important role to-wards the room-temperature ferromagnetic behavior of the doped nanowires. 相似文献
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采用溶胶凝胶法合成ZnS:TM(TM=Mn,Cu)水溶胶,研究了它们的光学性质。通过吸收光谱计算得到微粒的尺寸约为3~4nm,光致发射光谱为中给出了所对应掺杂中心的发射带,其能量来源于基质ZnS的吸收。通过旋涂法制备了ZnS:Cu纳米微粒EL器件,测定了其妄动电压和耐压值以及EL光谱强度与电压主的关系,初步探讨了可能的发光机理。 相似文献
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提出了两组分两出口分馏萃取体系中纯度梯度、积累量与纯度关系的数学表示式,利用静态和动态仿真计算程序,对不同分离系数、原料组成和出口纯度的两组分两出口分馏萃取体系的纯度、纯度梯度和积累量进行了模拟计算。结果表明:各组分两相纯度梯度在萃取段和洗涤段存在极值点。随着原料中难萃组分含量的增大,它在两相中的积累量随之增加,同时该组分萃取段纯度梯度的绝对值逐渐减小,而洗涤段的纯度梯度绝对值则逐渐增大。此外还比较了纯度梯度和积累量作为自控监测参数的特点,并得出对在线分析精度的要求和灵敏区位置。 相似文献
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