1H NMR spectral studies on the polymerization mechanism of indole and its derivatives

The existence of NH bond according to the hydrogen nuclear magnetic resonance ((1)H NMR) spectra of polyindole and its derivatives, such as poly(5-bromoindole), poly(5-cyanoindole), poly(5-nitroindole), poly(5-methylindole), proved polymerization of high-quality polyindoles, which were electrosynthesized from middle strong Lewis acid boron trifluoride diethyl etherate (BFEE) and its mixed electrolytes with additional diethyl ether, occurred at 2,3-position. The elongation of the conjugation length made the chemical shift of all the protons of polyindoles to lower field in comparison with those of monomers.     

The observation of abnormal signals in laser flash photolysis: a type of probable synchronized nuclear spin signals

In laser flash photolysis (LFP) work, noise-like signals were observed together with transient absorption decay spectra in time domain. Analyzed results show that it is a valuable resonance spectrum of excited state molecules, in which four molecular cases are given here. We proposed that this kind signal might originate from nuclear or nuclear and electron spin resonance features in the excited molecules based on radio wave frequency spectrum levels and the significant interaction with static magnetic field.     

Alkali-metal-catalyzed addition of primary and secondary phosphines to carbodiimides. A general and efficient route to substituted phosphaguanidines

Organo alkali metal compounds such as (n)BuLi and (Me3Si)2NK act as excellent catalyst precursors for the addition of phosphine P-H bonds to carbodiimides, offering a general and atom-economical route to substituted phosphaguanidines, with excellent tolerability to aromatic C-Br and C-Cl bonds.     

KH_2PO_4晶体的太赫兹-紫外光谱

实验测量了室温下磷酸二氢钾KH2PO4(KDP)晶体0.2～1.6THz的时域光谱,以及50～4000cm-1范围内的远红外光谱,200～2000nm的紫外-可见-红外光谱。KDP晶体的禁带宽度是5.91eV。在测量范围内有一个很宽的声子吸收带。从0.2～205.5THz吸收系数在35～80cm-1,声子吸收的低频端小于0.2THz。最高的纵光学模声子的频率νLO大约是205.5THz,由此求出这支声子的H—O键的力常数为13.13N·cm-1。     

Numerical method for solving matrix coefficient elliptic equation with sharp-edged interfaces

Solving elliptic equations with sharp-edged interfaces is a challenging problem for most existing methods, especially when the solution is highly oscillatory. Nonetheless, it has wide applications in engineering and science. An accurate and efficient method is desired. We propose an efficient non-traditional finite element method with non-body-fitting grids to solve the matrix coefficient elliptic equations with sharp-edged interfaces. Extensive numerical experiments show that this method is second order accurate in the L^∞ norm and that it can handle both sharp-edged interface and oscillatory solutions.     

Quantum state sharing with a genuinely entangled five-qubit state and Bell-state measurements

We construct several distinct schemes for tripartite Quantum state sharing (QSTS) of arbitrary single- and two-qubit states. Our schemes use genuinely entangled five-qubit state that has recently been introduced by Brown et al. [J. Phys. A 38 1119 (2005)] as the quantum channel. The Bell-state measurements and the single-qubit measurement are needed in our schemes. In comparison with the QSTS scheme using the same quantum channel [Phys. Rev. A 77 (2008) 032321], not joint measurement, which makes this scheme simpler than the latter.     

Pump power dependence of the electron-hole plasma luminescence in Ga-doped ZnO film

Time resolved two-photon absorption induced electron-hole plasma (EHP) luminescence of Ga-doped ZnO thin film was measured by an ultrafast optical Kerr gate (OKG) in femtosecond time regime. Experimental results showed that the buildup time of the EHP luminescence was strongly dependent on the excitation fluence. The dependence of the buildup time of EHP on excitation fluence probably arose mainly from the relaxation of the hot carriers due to the carrier-carrier interaction, which increased with the increase of excitation fluence.     

Interpolation algorithm for recovering the missing phase values in 3D measurement

In the three-dimensional (3D) phase measurement, some marks are usually adhered to the object in order to make the 3D registration process faster and easier. As covered with marks, local phase data are missing and have to be interpolated later. Considering the phase distribution nearby the marks, a gradient estimate (GE) interpolation algorithm is provided here. This algorithm recovers one pixel's missing phase value with the average of the estimated values which is calculated by gradients in eight directions nearby. Since this algorithm is a local processing, the missing phase values should be interpolated from the edge of the marks to the center. In the computer simulation and the practical experiment, compared with the same-size neighborhood mean (NM) algorithm and the Gerchberg-Saxton (GS) algorithm, this new algorithm achieves very good fit results with the least time. So it can be used as a practical tool for automatic missing phase interpolation.