少铅/无铅钙钛矿太阳能电池研究进展

钙钛矿太阳能电池作为一种新型的低廉高效的光伏材料在近年来备受关注。铅基钙钛矿太阳能电池有光电转换效率高、成本低、易制备等优点,然而由于铅的毒性以及由此带来的环境污染问题在很大程度上限制了其进一步商业化应用。因此人们开发出一系列新型无毒或低毒钙钛矿材料用于制备环境友好的少铅/无铅钙钛矿太阳能电池。本文简明扼要地介绍了钙钛矿材料的结构和形成条件,着重回顾了Sn基钙钛矿太阳能电池的发展历程,对ⅣA族元素Ge,ⅡA族元素Mg、Ca、Sr和Ba,ⅤA族元素Bi和Sb,ⅢA族元素In以及过渡金属元素Cu等取代或部分取代Pb,以及通过调节卤素X与正离子A的组成及配比来调控少铅或无铅钙钛矿材料性能进行了总结,对少铅/无铅钙钛矿太阳能电池器件研究进展进行了综述,并对其未来的发展方向进行了展望。     

高应变率下纯水冰和杂质冰的动态力学行为

通过采用大热惯性试件快速加载技术和波形整形技术,对3种冰材料在-18℃下的动态压缩性能进行测试,实验中试件达到了应力均衡和近似恒应变率加载等条件。通过实验波形对比分析,解释了反射波和透射波中的“双峰现象”。在700~2 700 s^-1的应变率范围内,纯冰试件的压缩强度为14.5~49.3 MPa,相比于准静态结果表现出明显的动态增强效应。含有杂质的冰试件总体峰值应力相比于纯水冰试件有较大提升,而峰值应力对应的平均应变在减小,这表明添加了杂质的冰试件动态模量增大,冰材料变得更硬,其抵抗变形的能力更强。b型试件所表现出的强度(41.3~51.6 MPa)较a、c型试件均有提高并且分散性较小,说明该试件中杂质与冰晶体之间的结合力较强,抑制了微裂纹的萌生、扩展、成核等过程。     

含裂纹弹性结构对声散射作用研究

研究了含裂纹的弹性结构对声的散射作用.应用分配形有限元和边界元相结合的方法于含裂纹的结构声相互作用问题.利用二级分形有限元方法对含裂纹结构进行离散,这将使得自由度大为减少;使用边界元方法计算外域散射声场,这将自动满足无限远辐射边界条件.数值结果初步表明:(1)随着裂纹深度的增加,结构声耦合系统的共振频率将下降;(2)裂纹附近的声场所受的影响更为明显.     

Lissoclibadins 8-14, polysulfur dopamine-derived alkaloids from the colonial ascidian Lissoclinum cf. badium

Seven new polysulfur alkaloids, lissoclibadins 8 (1)-14 (7), were isolated from an ascidian, Lissoclinum cf. badium, collected in Indonesia. The structures were assigned on the basis of their spectroscopic data and computational modeling study. Lissoclibadin 8 (1) had four identical dopamine-derived units, and this is the first instance of a tetramer. Lissoclibadin 9 (2) was the second example of trimers next to lissoclibadin 1 (8). Lissoclibadins 10 (3)-12 (5) were symmetric dimers, and 13 (6) had a dopamine and ethyl units connected by sulfide and disulfide bonds. Lissoclibadin 14 (7) was a varacin-type monomer. These compounds inhibited the colony formation of Chinese hamster V79 cells and cell proliferation of murine leukemia L1210 cells.     

Momentum dependence of quasiparticle spectrum and Bogoliubov angle in cuprate superconductors

The momentum dependence of the low energy quasiparticle spectrum and the related Bogoliubov angle in cuprate superconductors are studied within the kinetic energy driven superconducting mechanism. By calculation of the ratio of the low energy quasiparticle spectra at positive and negative energies, it is shown that the Bogoliubov angle increases monotonically across the Fermi crossing point. The results also show that the superconducting coherence of the low energy quasiparticle peak is well described by a simple d-wave Bardeen-Cooper-Schrieffer formalism, although the pairing mechanism is driven by the kinetic energy by exchanging spin excitations.     

A Facile Synthesis of 1-Substituted β-Carboline Derivatives via Minisci-Reaction

A mild and efficient one-pot reaction for the synthesis of 1-substituted β-carboline derivatives via the Minisci reaction has been developed with good yields and selectivity. In addition, the mechanism of the 1-substituted β-carboline derivatives by means of the nucleophilic radical is described.     

A boundary element method for calculating elastic waves scattered by axisymmetric inclusion

A Boundary Element Method (BEM) is described to compute the scattering of elastic waves by an axisymmetric inclusion in an infinite elastic medium. The boundary loads applied to the inclusion is expanded in terms of Fourier series in an infinite space. The boundary integral equation is solved in the general direction of the axisymmetric inclusion by BEM. The problem of the 3-D scattering of elastic waves is reduced to a 1-Done. According to the geometric features of the axisymmetric in clusion the ring shell elements are adopted in this method. A comparison is made with other BEM methods. The numerical results show this method can reduce the amount of calculation and enhance the speed of convergence. Supported by Foundation of Ph. D Program of State Education Commission of China     

BOUNDARY VALUE PROBLEMS OF TWO-DIMENSIONAL ANISOTROPIC BODY WITH A PARABOLIC BOUNDARY

Based upon Stroh formalism we derive a novel and convenient scheme for determiningthe elastic fields of a two-dimensional anisotropic body with a parabolic boundary subject to two kindsof boundary conditions, which are free surface and rigid surface, respectively. The correspondingGreen's functions are found by using the conformal mapping method. When the parabolic curve de-generates into a half-infinite crack or rigid inclusion, the singular stress fields near the tip of defectsare obtained. In particular, those Green's functions for a concentrated moment M_0 applied at a pointon the parabolic curve are also studied. It is easily found that arbitrary parabolic boundary value prob-lems can be solved by using these Green's functions and associate integrals.     

布拉格衍射及其应用

本文通过用微波对模拟晶体衍射,对110面及100面不同入射角与衍射强度的测量,证明了入射波一定时衍射极大由晶面间距离决定。     

ANALYSIS ON BUCKLING AND POSTBUCKLING OF DELAMINATION IN 3D COMPOSITES

In this paper, the problem of axisymmetric buckling and postbuckling of a circular thin-film delamination bridged by through-thickness fiber tows in 3D composites is presented. An iterativeprocedure based on Taylor's series expansion is used to generate a family of nondimensionalized post-buckling solutions of the above problem by yon Karman's nonlinear plate theory. Attention is fo-cused, herein, on the effects of the bridge force of through-thickness fibers on the buckling and post-buckling behavior of the delamination. It is found that fiber bridge not only increases the ability of re-sisting delamination buckling and postbuckling, but also brings on the jump of the delamination deflec-tion mode during the postbuckling phase. Consequently the behavior of the composite structure with de-lamination is greatly improved, such as increasing the residual strength and prolonging the service life.