A facile sulfur vapor assisted reaction method to grow boron nitride nanorings at relative low temperature

Boron nitride (BN) nanorings were synthesized using a sulfur vapor assisted solid-state method at 600 degrees C. The rings had typical diameters of 100-300 nm, and the shells were 5-20 nm thick and about 50 nm wide. On the basis of the characterization of X-ray powder diffraction pattern (XRD), X-ray photoelectron spectroscopy (XPS), and Fourier transformation infrared spectroscopy (FTIR) measurement, the as-prepared product was pure-phase hexagonal BN. High-resolution transmission electron microscopy (HRTEM) images proved that the nanorings were formed through the coiling of the (002) planes of hexagonal BN. A possible growth process for BN nanorings is suggested.     

Extension of Floquet''''s theory to nonlinear quasiperiodic differential equations

In this paper, we consider the following autonomous system of differential equations: x = Ax f(x,θ), θ = ω, where θ∈Rm, ω = (ω1,…,ωm) ∈ Rm, x ∈ Rn, A ∈ Rn×n is a constant matrix and is hyperbolic, f is a C∞ function in both variables and 2π-periodic in each component of the vector e which satisfies f = O(||x||2) as x → 0. We study the normal form of this system and prove that under some proper conditions this system can be transformed to an autonomous system: x = Ax g(x), θ = ω. Additionally, the proof of this paper naturally implies the extension of Chen's theory in the quasi-periodic case.     

单色CCD记录多波长数字全息图及再现像彩色显示

对多波长数字全息图的记录和再现像的彩色显示问题进行了研究.从菲涅耳近似算法出发,对在记录距离一定情况下,不同波长全息图数字再现像的像元所表示的几何尺寸会因波长不同而不同,从而导致各波长再现像无法重合的情况进行了讨论.通过理论分析,讨论了不同波长全息图像素数与再现像像元之间的关系、不同波长全息图记录距离与再现像像元之间的关系,据此得出的解决不同波长再现像重合问题的方法及其对再现像的影响和适用范围等问题；并对合成再现像中原始色彩信息改变及其解决办法进行了分析.通过无透镜傅里叶变换数字全息方法,以632.8 nm和532.0 nm两种波长的激光为光源,用单色CCD进行记录,验证了方法的可行性.     

Quantum interference effect in the charge transport through single-molecule benzene dithiol junction at room temperature: An experimental investigation

The electrical characterization on single-molecule benzene dithiols with different connectivities showed that the meta-BDT has the lowest conductance, which suggested that there is destructive quantum.     

A New Approach for Preparing Effective Inhibition Film on Copper Based on Self-assembled Process

A new method for preparing effective inhibition film on copper has been developed.Pheylthiourea(PT) was firest absorbed to copper surface to form a monolayer.1-Dodecanethiol(DT) was then assembled on the surface for modification.Finally,Ac voltage was loded on copper covered the mixed film to improve it further.After these processes,an effective inhibition film was gained because of its high charge transfer resistance and low corrosion current density shown in electrochemical impedance spectra and polarization.The inhibition efficiency was more than 97%.     

Dimericbiscognienynes B and C: New diisoprenyl-cyclohexene-type meroterpenoid dimers from Biscogniauxia sp.

Till now, only three diisoprenyl-cyclohexene/ane-type meroterpenoid dimers have been identified. The isolation of two new diisoprenyl-cyclohexene-type meroterpenoid dimers (dimericbiscognienynes B and C) from Biscogniauxia sp. 71-10-1-1 added new members to this family.