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171.
采用巯基化合物修饰的CdTe量子点构建了量子点(供体)-罗丹明6G(受体)荧光共振能量转移体系, 研究了CdTe量子点与牛血清白蛋白(BSA)的相互作用. 结果表明, CdTe量子点与BSA相互作用后提高了CdTe量子点-罗丹明6G 体系的荧光共振能量转移(FRET)效率, 减小了CdTe量子点和罗丹明6G分子间的距离(r), 证实BSA是通过其色氨酸(Trp)残基与CdTe量子点表面金属发生配位作用而直接结合到量子点表面的. 相似文献
172.
This paper introduces a new two-lane high-order continuum model
by embedding the two delay time scales continuum traffic model presented by
Xue (2003 Phys. Rev. E 68 066123) into the multi-lane model proposed
by Daganzo (1997 Transpn. Res. B 31 83) with the consideration of
the coupling effect between the vehicles of two lanes in
instantaneous traffic situation and lane-change effect. In the novel model,
the coupling effect of two lanes and phenomena of lane change, which were
not discussed in Daganzo's model and Xue's model, are taken into account.
Numerical simulation shows that it is in accordance with real traffic flow.
This obviously indicates that the new phenomenon and behaviour are analogous
results as single lane presented by Xue, and the proposed model is more reasonable on
two lanes. Furthermore, the generation rate between two lanes is also
investigated. The results show that the formation and diffusion of traffic
shock wave can be better simulated on two lanes. 相似文献
173.
On the basis of the full velocity difference (FVD) model,
an improved multiple car-following (MCF) model is proposed by taking
into account multiple information inputs from preceding vehicles.
The linear stability condition of the model is obtained by using the
linear stability theory. Through nonlinear analysis, a modified
Korteweg-de Vries equation is constructed and solved. The traffic
jam can thus be described by the kink--antikink soliton solution for
the mKdV equation. The improvement of this new model over the
previous ones lies in the fact that it not only theoretically retains many
strong points of the previous ones, but also performs more
realistically than others in the dynamical evolution of congestion.
Furthermore, numerical simulation of traffic dynamics shows that the
proposed model can avoid the disadvantage of negative velocity that
occurs at small sensitivity coefficients λ in the FVD model by
adjusting the information on the multiple leading vehicles. No
collision occurs and no unrealistic deceleration appears in the
improved model. 相似文献
174.
A viscous continuum traffic flow model with consideration of the coupling effect for two-lane freeways
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In this paper, the viscous continuum traffic flow model for a single
lane is extended to the traffic flow for two-lane freeways. The
proposed model is a higher-order continuum model considering the
coupling and lane changing effects of the vehicles on two adjacent
lanes. It results from integrating the Taylor series expansion of
the viscous continuum traffic flow model proposed by Ge (2006 Physica
A 371 667) into the multi-lane model presented by
Daganzo (1997 Transpn. Res. B 31 83). Our proposed
model may be used to describe non-anisotropic behaviour because of
lane changing in multi-lane traffic. A linear stability analysis
is given and the neutral stability condition is obtained. Also,
issues related to lane changing, shock waves and rarefaction waves,
local clustering and phase transition are investigated through a
simulation experiment. The simulation results show that the proposed
model is capable of explaining some particular traffic phenomena
commonly observable in real world traffic flow. 相似文献
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通过在氮中引入杂质离子,利用高压手段获得具有新奇结构的多氮化合物是目前被广泛应用的研究方法.钙氮材料在催化、光电方面有着广泛的应用.具有较低电离能的钙(Ca)元素很容易和氮原子形成离子键钙氮化物.高压为寻找新型钙氮化合物提供了全新的技术途径.因此,利用高压方法,通过改变配比的方式,寻找具有新奇特性的钙氮高压结构,是一项非常有意义的工作.本文利用基于密度泛函理论的结构搜索方法,在100 GPa条件下,通过预测得到了一个稳定的Ca5N4相.该结构内部氮原子之间以N-N共价单键键合,氮原子和钙原子之间是离子键相互作用,且钙氮之间的电荷转移量为1.26 e/N atom.能带结构计算表明P 21/c-Ca5N4是一个直接带隙为1.447 eV的半导体结构.最后,系统地给出了该结构的拉曼振动光谱,并指认了拉曼振动模式,为实验合成该结构提供了理论指导. 相似文献
180.
近年来,钙钛矿光伏电池(PSCs)取得了突飞猛进的发展,迄今最高认证光电转换效率达到25.7%,但是钙钛矿材料常使用有毒的重金属元素铅,对环境和人体都有极大的危害,不利于其实际应用,因此发展无铅PSCs受到越来越多的关注。锡基钙钛矿材料具有优异的光电性质,特别是带隙窄、载流子迁移率高和激子复合能低,是无铅钙钛矿中最具有潜力的材料。反式(p-i-n型)锡基PSCs由于低迟滞效应、可低温制备及低成本等优点获得普遍关注,取得了一系列重要突破,目前最高效率已经突破14%,具有巨大的发展潜力。鉴于反式锡基钙钛矿太阳能的迅速发展,本文系统综述了反式锡基PSCs制备及稳定性研究进展,尤其关注反式锡基PSCs的界面修饰、锡基钙钛矿材料性能、构筑高质量锡基钙钛矿薄膜的方法以及提高稳定性的策略,并讨论了锡基PSCs的前景展望。 相似文献