排序方式: 共有9条查询结果,搜索用时 15 毫秒
1
1.
石墨烯条带的电子结构与性质:电场及长度效应 总被引:1,自引:0,他引:1
在密度泛函理论(DFT)和含时密度泛函理论(TDDFT)的基础上对宽度上含有8个zigzag链的石墨烯条带(8-ZGNR)的基态和激发态的性质进行了理论研究,着重考察了条带长度及电场的影响.B3LYP杂化泛函的计算结果显示:在基态上,8-ZGNR的最低能量态并不具有磁性,随着长度的增加,才会显示出反铁磁的性质.静电场的加入使8-ZGNR显示出反铁磁性和半金属性.在激发态上,诱导电子会随着外激光脉冲的变化而发生移动和变化,但是相比而言,α自旋电子更容易被激发而产生较明显的诱导电子密度,而β自旋电子则更容易脱离外激光场的控制而产生非绝热现象. 相似文献
2.
Chaos in motor system is beneficial in some niche fields such as industrial mixing processes. In this paper, we investigate the issue of inducing chaos in Brushless DC Motor (BLDCM). Based on the differential-geometry control theory, a nonlinear function of current time-delayed control is derived. Analysis shows that the feedback scheme can induce the BLDCM operating in a stable regime to chaotic state across a large range of domain of control parameters, and if the values of control parameters α and β are set at an appropriate level, the variation of the time delay τ becomes insensitive to the occurrence of chaos, which is available in the compensation with inaccuracy of time-delay control. 相似文献
3.
本文报告了PIXE(Proton Induce X-ray Emission)技术分析Si基片热扩Ni的深度剖面,质子能量为0.7至2.5MeV,比较了两种理论计算结果的差异,并与其它测量方法得的结果作了比较。 相似文献
4.
5.
本文报道了利用圆二色性(CD)研究了环糊精(CD_x)与o-、m-、p-氯代苯甲酸包结物的包结形态,根据Kajtar扇形规则确定了客体分子在环糊精腔内的位置。 相似文献
6.
Inducer can induce new active composition and increase the content of the active composition in the plant. In this paper, we investigated the synthesis and accumulation of phytoalexin in cucumber seedlings which were induced by chemical inducer of the salicylic acid (SA) and physical inducer. Analyzed by experiment of antifungal activity, thin-layer chromatography (TLC) and high-performance liquid chromatography (HPLC), the result was that both SA and stress can induce the synthesis and accumulation of phytoalexin in cucumber seedlings. But the content of phytoalexin induced by SA was lower than it induced by stress. And in this paper, another conclusion was that the transduction of physical signal and the chemical signal in the plant depended on the adhesion between cell wall and plasma and active oxidative species producted by stimulation. 相似文献
7.
Pressure has a specific influence on the light scattering in those liquids in which all molecules have an unsaturated double bond C=C. Strong changes of intensity of transmitted and scattered light in oleic acid were observed during its transition to the high-pressure phase. In this paper, local order in liquid of oleic acid has been studied using the X-ray diffraction photographic Laue method. Experiments were run at room temperature under atmospheric pressure as well as under pressures up to 0.25 GPa. At pressures above 0.2 GPa a strong increase of ordering of molecules, similar to a smectic liquid crystal phase, has been observed. This confirms results obtained previously by studies of light scattering under high pressure. 相似文献
8.
9.
In this work, we validate and analyze the results of previously published cross docking experiments and classify failed dockings based on the conformational changes observed in the receptors. We show that a majority of failed experiments (i.e. 25 out of 33, involving four different receptors: cAPK, CDK2, Ricin and HIVp) are due to conformational changes in side chains near the active site. For these cases, we identify the side chains to be made flexible during docking calculation by superimposing receptors and analyzing steric overlap between various ligands and receptor side chains. We demonstrate that allowing these side chains to assume rotameric conformations enables the successful cross docking of 19 complexes (ligand all atom RMSD < 2.0 A) using our docking software FLIPDock. The number of side receptor side chains interacting with a ligand can vary according to the ligand's size and shape. Hence, when starting from a complex with a particular ligand one might have to extend the region of potential interacting side chains beyond the ones interacting with the known ligand. We discuss distance-based methods for selecting additional side chains in the neighborhood of the known active site. We show that while using the molecular surface to grow the neighborhood is more efficient than Euclidian-distance selection, the number of side chains selected by these methods often remains too large and additional methods for reducing their count are needed. Despite these difficulties, using geometric constraints obtained from the network of bonded and non-bonded interactions to rank residues and allowing the top ranked side chains to be flexible during docking makes 22 out of 25 complexes successful. 相似文献
1