基于八氢联萘酚的大位阻手性发光材料构建及光电性质研究

以手性发光材料为发光中心制备能够直接发射出圆偏振电致发光(circularly polarized electroluminescence, CPEL)的器件, 即CP-organic light-emitting diode (CP-OLED), 在3D显示领域有极大的应用前景. 本工作设计了基于八氢联萘酚的手性热激活延迟荧光材料(S/R)-OBN-tBuCz, 八氢联萘酚作为有效的手性源, 而叔丁基咔唑取代的氰基苯作为高效发光部分. 八氢联萘酚外围较多的氢原子以及较大的叔丁基可以有效增加手性发光分子的空间位阻, 降低堆积效应, 抑制浓度淬灭, 有效提升器件的发光效率. 所合成的手性发光材料展现出明亮的绿光发射(523 nm)、高的荧光量子产率(85.2%)、较小的单线态-三线态能级差ΔE_ST (0.05 eV)和优秀的热稳定性. 圆二色(CD)与圆偏振发光(CPL)光谱显示出明显的对称圆偏振发光信号, 且溶液中的g_PL为+8.6×10^-4和–6.5×10^-4. 基于(S/R)-OBN-tBuCz的电致发光器件表现出优异性能: 起亮电压为3.9 V, 最大亮度为27709 cd•m^-2, 最大电流效率为43.8 cd•A^-1, 最大功率效率为33.5 lm•W^-1, 最大外量子效率为12.4%, 效率滚降很低, 并显示出明显的圆偏振电致发光信号, g_EL分别为+1.57×10^-3和–0.90×10^-3. 大位阻手性发光材料的设计有助于实现高效的CP-OLED, 该研究能促进手性发光材料及圆偏振电致发光器件等相关研究领域的发展.     

超高层建筑受大型高速飞行物撞击所致非连续性坍塌模拟与研究

为了解大型高速飞行物撞击超高层建筑后,建筑物塌落过程及其特征,使用基于颗粒流的PFC3D作为平台对坍塌过程进行模拟。所构建的超高层建筑为核心筒-框架结构,飞行物由较大的三个颗粒组成,其撞击速度为720km/h,撞击高度为建筑侧面250m和100m。研究了撞击物进入层间运动的特征,及在两种高度撞击后的坍塌过程。模拟结果表明,飞行物非直接撞击核心筒时建筑不会发生整体破坏,核心筒的受撞破坏是建筑坍塌破坏的关键。建筑高处受撞击后坍塌可分为两个阶段,其现象和原因各不相同。指出了建筑高处和低处受撞坍塌过程的三点不同。最后分析了撞击塌落后的地面影响范围及特征。     

Anomalously Large Pockels Effect in ZnO‐F Single Crystalline Films Deposited on Bare Glass

Large linear electrooptics (the Pockels effect) of up to 17 pm/V for the wavelength 435 nm has been observed in ZnO films doped by fluorine and deposited on bare glass. In order to describe the phenomenon observed, a complex approach, including self‐consistent band structure calculations together with the appropriate molecular dynamics simulations of the interfaces, was applied. The origin of the effect observed is linked to substantial charge density non‐centrosymmetry between the wurtzitelike crystalline films and the bare glass substrate, as well as to additional charge density polarisation caused by the fluorine.     

修正多重尺度法在圆薄板大挠度弯曲问题中的应用及其渐近性研究(Ⅰ)

本文应用修正多重尺度法研究圆板在铰链和简单支承条件下的大挠度弯曲。作出其级数解,分析其边界层效应和证明其渐近性。     

A modified Hellinger-Reissner variational functional including only two independent variables for large displacement of thin shallow shell

I.IntroductionThemathematicalbasisofthefiniteelementmethodisthevariationalprinciple,andthedevelopmentofthefiniteelementmethodimpelsthevariationalprincipleitselftogetanewdevelopment.ThevariationalprincipIepresentedbyT.H.H.PianandP.Tongistheonethatthecontin…     

A new technique for solving non-axially symmetrical large deflection of elastic and thin circular plates

I.IntroductionBecauseofthenonlinearityoflargedeflectionproblemofthinplates,itisquitedifficulttoobtainitsaccuratesolution.Thereforeanapproximatesolutiontoitobtainedbyanappropriatemethodisdesired.Thetechniquesocalledperturbation,beingabletogiveresultswithadequateprecision,isofaprevailingandeffectiveonetobegenerallyaccepted.W.Z.Chientl]succesfullyobtainedanapproximatesolutiontothelargedeflectionproblemofthincircularplatefie-curalaxisymmetricallybyperturbationtechnique.X.Z.Wangl'Jgainedthedispl…     

THE LARGE TIME CONVERGENCE OF SPECTRAL METHOD FOR GENERALIZED KURAMOTO-SIVASHINSKY EQUATION (Ⅱ)

1.IntroductionInthepaper[1],westudedthegeneralizedKuramotrySivashinskyequationWeProvedtheexistenceanduniquenessofglobalsolutionforperiodicinitialproblemandgavethelargetimeerrorestimationforthesolutionofcontinuousspectralmethod.Theaimofthispaperistostudyfullydiscretespectralmethodandthelongtimebehaviorofthesolutionofthissystem.In61wegiventhelargetimeerrorestimationforfullydiscretesolutionofspectralmethod.In52weprove-theexistenceofapproximateattractorsAN,4anding3weprovetheconvergenceofapproal…     

Secondary instability of large scale structure in free turbulent shear layer

The secondary instability theory is used to study the behavior of spatially growingdisturbance in free turbulent shear layer.The numerical results indicate that secondaryinstability of subharmonic mode shows a strong choice of spanwise wavenumber andthe maximum growth two dimensional case.In contrast to that secondary instabilities of the fundamental mode occur in a wide scope of spanwise wavenumber.We have found so called translative at β=0 and bifurcation phenomenon for an amplitude of the KH wave larger than 0.06.Dey words instability,large scale structure,bifurcation     

A Theory of Evolving Natural Constants Based on the Unification of General Theory of Relativity and Dirac's Large Number Hypothesis

Taking Dirac's large number hypothesis as true, we have shown [Commun. Theor. Phys. (Beijing, China) 42 (2004) 703] the inconsistency of applying Einstein's theory of general relativity with fixed gravitation constant G to cosmology, and a modified theory for varying G is found, which reduces to Einstein's theory outside the gravitating body for phenomena of short duration in small distances, thereby agrees with all the crucial tests formerly supporting Einstein's theory. The modified theory, when applied to the usual homogeneous cosmological model, gives rise to a variable cosmological tensor term determined by the derivatives of G, in place of the cosmological constant term usually introduced ad hoc. Without any free parameter the theoretical Hubble's relation obtained from the modified theory seems not in contradiction to observations, as Dr. Wang's preliminary analysis of the recent data indicates [Commun. Theor. Phys. (Beijing, China) 42 (2004) 703]. As a complement to Commun. Theor. Phys. (Beijing, China) 42 (2004) 703 we shall study in this paper the modification of electromagnetism due to Dirac's large number hypothesis in more detail to show that the approximation of geometric optics still leads to null geodesics for the path of light, and that the general relation between the luminosity distance and the proper geometric distance is still valid in our theory as in Einstein's theory, and give the equations for homogeneous cosmological model involving matter plus electromagnetic radiation. Finally we consider the impact of the modification to quantum mechanics and statistical mechanics, and arrive at a systematic theory of evolving natural constants including Planck's ħ as well as Boltzmann's k_B by finding out their cosmologically combined counterparts with factors of appropriate powers of G that may remain truly constant to cosmologically long time.     

Generation of Maximally Entangled States of Two Nonidentical Atoms in Cavity QED

We have discussed the system which consists of two nonidentical two-level atoms trapped simultaneously in a large-detuned single-mode cavity field in this paper. The results show that it is possible to generate maximally entangled states for two nonidentical two-level atoms only if the cavity frequency and difference of two nonidentical atoms transition frequency are selected and the cavity-atom interacation time is controlled.