Synthesis of spiro thiazolo[3,2‐a]pyrimidine compounds by one‐pot sequential 1,3‐dipolar cycloadditions

A new class of spiro thiazolo[3,2‐a]pyrimidine compounds were synthesized by the one‐pot sequential 1,3‐dipolar cycloaddition of azomethine ylide (generated from isatin and sarcosine)–nitrile oxide to 2‐arylmethylidene‐6,7‐dihydro‐5H‐thiazolo[3,2‐a]pyrimidin‐3‐ones in moderate yields. The structures of all the products were characterized thoroughly by NMR, MS, IR, elemental analysis, and NMR together with X‐ray crystallographic analysis. J. Heterocyclic Chem., (2011).     

Mechanochromic luminescent property of a polypeptide-based dendron

We report herein the mechanochromic luminescent property of a dendritic polypeptide with a fluorescent aromatic moiety at the focal point. The different luminescent property of 1 under mechanical stimulus is attributed to the switch of self-assembled structures. Moreover, the photoluminescence property of 1 also depends on the thermal history.     

The investigation of the interaction between NCP-EDA and bovine serum albumin by spectroscopic approaches

The fluorescence and ultraviolet spectroscopies were explored to study the interaction between N-confused porphyrins-edaravone diad (NCP-EDA) and bovine serum albumin (BSA) under simulative physiological condition at different temperatures. The experimental results show that the fluorescence quenching mechanism between NCP-EDA and BSA is a combined quenching (dynamic and static quenching). The binding constants, binding sites and the corresponding thermodynamic parameters (ΔG, ΔH, and ΔS) of the interaction system were calculated at different temperatures. According to F?rster non-radiation energy transfer theory, the binding distance between NCP-EDA and BSA was calculated to be 3.63 nm. In addition, the effect of NCP-EDA on the conformation of BSA was analyzed using synchronous fluorescence spectroscopy.     

Parameter identification of electronic throttle using a hybrid optimization algorithm

Aiming at the problems in parameter identification of an electronic throttle, this paper proposes a novel hybrid optimization algorithm to search the optimal parameter values of the plant. The parameter identification of an electronic throttle is considered as an optimization process with an objective function minimizing the errors between the measurement and identification, and the optimal parameter values of the plant are searched by using a hybrid optimization algorithm. The proposed hybrid optimization algorithm, effective combination of parallel chaos optimization algorithm (PCOA) and simplex search method, preserves both the global optimization capability of PCOA and the accurate search ability of simplex search method. Simulation and experiment results have shown the good performance of the proposed approach.     

在激光等离子体中产生高电荷态离子的新途径

本文提出一种在激光等离子体中产生高丰度高电荷态离子的新途径，即通过共振光激发和碰撞电离混合过程来实现，模型计算表明，这一混合过程对提高高电荷态离子丰度的有效性，有关实验也证明这一过程的重要作用。     

A Simple Theoretical Model for Ring and Nanotube Radial Breathing Mode

The radial breathing modes (RBMs) of (MgO)_n and (BeO)_n rings (n=3-10) were calculated using the density functional theory at B3LYP/6-31G(d) level. It was found that for large rings, the radial breathing mode (RBM) frequency was inversely proportional to the centre diameter, but the variation of bond length may lead to deviations from a linear behavior. The deviations caused by inverse cubic term of diameter and variation of bond length, became dramatic with the decrease of ring diameter. From the point of chemical bond view, using one-dimensional harmonic oscillator and the method of cascade and parallel connection of “springs”, the linear relation and deviations were explained. The model can be applied to nanotubes.     

超薄靶激光质子加速实验研究

在超短超强飞秒SILEX-Ⅰ激光装置上,开展了薄膜靶激光质子加速的实验研究。实验发现激光预脉冲、靶厚度对质子加速有很大的影响。在激光强度3×1018~3×1019W/cm2条件下,采用前表面厚度为3μm铜、后表面镀4μm厚CH靶,质子的最大能量达到3.15 MeV。而对190 nm厚CH膜靶,质子的最大能量为0.54 MeV。初步研究了激光偏振对质子加速的影响,相同激光功率条件下,圆偏振激光加速产生的质子最大能量略低于P偏振打靶。这些结果与靶后鞘层加速机制相一致。     

Phosphorus Analogues of Methyl Nitrite and Nitromethane: CH3OPO and CH3PO2

Methoxyphosphinidene oxide (CH₃OPO) and isomeric methyldioxophosphorane (CH₃PO₂) are key intermediates in the degradation of organophosphorus compounds (OPCs). Unlike the nitrogen analogues CH₃ONO and CH₃NO₂, the experimental data for these two prototypical OPCs are scarce. By high‐vacuum flash pyrolysis (HVFP) of the diazide CH₃OP(O)(N₃)₂ at 1000 K, the cis and trans conformers of CH₃OPO have been generated in the gas phase and subsequently isolated in cryogenic Ar and N₂ matrices for IR spectroscopic characterization. Upon 266 nm laser irradiation of CH₃OPO, cis→trans conformational conversion occurs with concurrent isomerization to CH₃PO₂. The spectroscopic identification of CH₃OPO and CH₃PO₂ is supported by D‐, ¹³C‐, and ¹⁸O‐isotope labeling and quantum chemical calculations at the CCSD(T)‐F12a/cc‐pVTZ‐F12 level using configuration‐selective vibrational configuration interaction (VCI).