Blow-up rate of the unique solution for a class of one-dimensional problems on the half-line

For more general nonlinear term g, the paper shows the exact blow-up rate of the unique solution ψ(t) to the singular boundary value problem

     

Diastereoselective cycloadditions of a soluble polymer-supported substituted allyl alcohol derived from Baylis-Hillman reaction with nitrile oxides

A diastereoselective cycloaddition of a soluble polymer-supported Baylis-Hillman adduct with nitrile oxides is described. The reaction has shown to proceed with moderate diastereoselectivity, favoring the syn isomer of the resulting 3,5-substituted isoxazolines. The stereochemistry of the products has been assigned using ¹H NMR studies. The structure of one of the diastereomers has been determined by single-crystal X-ray crystallographic analysis.     

Starburst triarylamine based dyes for efficient dye-sensitized solar cells

We report here on the synthesis and photophysical/electrochemical properties of a series of novel starburst triarylamine-based organic dyes (S1, S2, S3, and S4) as well as their application in dye-sensitized nanocrystalline TiO2 solar cells (DSSCs). For the four designed dyes, the starburst triarylamine group and the cyanoacetic acid take the role of electron donor and electron acceptor, respectively. It was found that the introduction of starburst triarylamine group to form the D-D-pi-A configuration brought about superior performance over the simple D-pi-A configuration, in terms of bathochromically extended absorption spectra, enhanced molar extinction coefficients and better thermo-stability. Moreover, the HOMO and LUMO energy levels tuning can be conveniently accomplished by alternating the donor moiety, which was confirmed by electrochemical measurements and theoretical calculations. The DSSCs based on the dye S4 showed the best photovoltaic performance: a maximum monochromatic incident photon-to-current conversion efficiency (IPCE) of 85%, a short-circuit photocurrent density (J(sc)) of 13.8 mA cm(-2), an open-circuit photovoltage (V(oc)) of 0.63 V, and a fill factor (ff) of 0.69, corresponding to an overall conversion efficiency of 6.02% under 100 mW cm(-2) irradiation. This work suggests that the dyes based on starburst triphenylamine donor are promising candidates for improvement of the performance of the DSSCs.     

Synthesis of FeS2/CoS heterostructure microspheres as anodes for high-performance Li-ion batteries

Journal of Solid State Electrochemistry - FeS2/CoS and FeS2/CoS/C composites were synthesized by solvothermal method and following vapor phase vulcanization at mild temperature with binary oxide...     

Existence of multiple positive periodic solutions for functional differential equations

In our paper, by employing Krasnoselskii fixed point theorem, we investigate the existence of multiple positive periodic solutions for functional differential equations

     

浅谈化学奥林匹克活动小组在实验教学中的作用

根据多年的教学教研实践,我认为上好化学实验课,可以利用化学奥林匹克活动小组的化学特长来提高和扩大教师在实验教学中的主导作用,从而更有力地调动全体学生参与化学实验的自觉性和积极性,提高实验教学的效果。     

Two Theorems on the Hubbard-Hirsch Model

In this paper, the two theorems on the Hubbard-Hirsch model are shown rigorously. For positive on-site interaction U, the model on some bipartite lattices has a weak ferromagnetic ground state at half filling. For negative U, the ground state of the model on some bipartite lattices possesses off-diagonal long-range order within a finite range of the electron filling factor.     

含剧烈振荡波函数积分J(n,X)的研究(I)

在天体物理与等离子体有关的大量原子过程中,需要精确计算大量含剧烈振荡波函数的积分.直接数值积分既笨拙又不能保证所需精度。为此,对不同波数的情形,采用Belling渐近展开法,提高了其中位相的精度;对相同波数的情形,则给出了J(n,X)的解析表达式。计算模拟结果表明有足够高的精度.     

表面修饰Ag_2S纳米微粒的合成及摩擦学行为研究

在水醇混合介质中,采用同阳离子共沉淀法合成了有机化合物表面修饰的Ａｇ２Ｓ纳米微粒,在高速钢基底上制备成膜,研究了它的摩擦学特性。结果表明：修饰后的Ａｇ２Ｓ纳米微粒粒径小,性能稳定,在有机介质中分散成透明溶液。ＡｇＤＤＰ膜和Ａｇ２Ｓ ＤＤＰ膜均可显著降低钢基底的摩擦系数。研究证实表面修饰Ａｇ２Ｓ纳米微粒的摩擦作用机制是在较低负荷下表面修饰层起主要作用,在较高负荷下Ａｇ２Ｓ纳米核起主要的承载和减摩抗磨作用。     

聚苯胺的合成及其摩擦学行为的研究

选择合适的ＳＤＢＳ／ 苯胺／ 水三组分Ｏ／Ｗ 微乳液与苯胺单体共存的两相体系,以单体相为单体源,在Ｏ／Ｗ 三组分微乳液中进行了苯胺聚合,成功地制备出了能够稳定分散于石腊油的聚苯胺微粒。并在四球试验机上研究合成条件、负荷、浓度对其摩擦学行为的影响。结果表明：聚苯胺有一定的减摩抗磨效果