Regioregular poly(3-hexyl)selenophene: a low band gap organic hole transporting polymer

The synthesis of regioregular poly(3-hexyl)selenophene is reported, and its optical and electrical properties are compared to those of regioregular poly(3-hexyl)thiophene.     

Probing Effect of Solvation on Photoexcited Quadrupolar Donor-Acceptor-Donor Molecule via Ultrafast Raman Spectroscopy

The symmetric and quadrupolar donor-acceptordonor (D-A-D) molecules usually exhibit excitedstate charge redistribution process from delocalized intramolecular charge transfer (ICT) state to localized ICT state. Direct observation of such charge redistribution process in real-time has been intensively studied via various ultrafast time-resolved spectroscopies. Femtosecond stimulated Raman spectroscopy (FSRS) is one of the powerful methods which can be used to determine the excited state dynamics by tracking vibrational mode evolution of the specific chemical bonds within molecules. Herein, a molecule, 4, 4′-(buta-1, 3-diyne-1, 4-diyl)bis(N, N-bis(4-methoxyphenyl)aniline), that consists of two central adjacent alkyne (-C≡C-) groups as electron-acceptors and two separated, symmetric N, N-bis(4-methoxyphenyl)aniline at both branches as electron-donors, is chosen to investigate the excited-state photophysical properties. It is shown that the solvation induced excited-state charge redistribution in polar solvents can be probed by using femtosecond stimulated Raman spectroscopy. The results provide a fundamental understanding of photoexcitation induced charge delocalization/localization properties of the symmetric quadrupolar molecules with adjacent vibrational markers located at central position.

     

液相酸溶液后补钛合成Ti-MWW分子筛

首先在含钠体系硼酸与哌啶用量较少的条件下水热合成B-MWW分子筛前驱体, 然后对其进行液相酸溶液后补钛, 合成了高结晶度的Ti-MWW分子筛. 利用粉末X射线衍射、 氮气吸附-脱附分析、 紫外-可见漫反射光谱和紫外拉曼光谱等技术考察了硅钛比、 温度等后补钛参数对所合成Ti-MWW分子筛的织构性质、 钛物种周围配位环境及催化1-己烯环氧化性能的影响, 确定适宜液相后补钛的硅钛比为30, 温度为373 K. 并且发现, 在后补钛体系中添加少量氟化铵可显著提高所合成Ti-MWW分子筛对1-己烯环氧化的催化活性. 本研究不仅证实了酸处理Ti-MWW分子筛前驱体的脱硼补钛机制, 也为Ti-MWW分子筛的合成提供了一种新的方法与思路.     

Increase in Axial Compressibility in a Spinning Van der Waals Gas

We investigated the adiabatic compression along the axial direction of a spinning Van der Waals gas by applying theoretical analysis and molecular dynamics (MD) simulations. Based on the analytical results, the rotation-induced compressibility increase effect is significant in a Van der Waals gas, while the attraction term in the Van der Waals equation of states (EOS) contributes significantly to the compressibility increase in a spinning system. We conducted MD simulations to the axial compression of a spinning gas, whose state is far from the ideal gas state, and further demonstrated that the rotation-induced compressibility increase effect in a dense state is robust, implying that such a phenomenon can be detected in experiments under high-energy-density conditions.     

Nafion–ZrO2 nanoparticle–ionic liquid nanobiocomposite for the direct electrochemistry of myoglobin

Journal of Solid State Electrochemistry - A nanobiocomposite was perpared by mixing zirconia nanoparticle with ionic liquid 1-ethyl-3-methylimidazolium tetrafluoroborate and Nafion together, which...     

Discontinuous Galerkin Methods for Solving a Frictional Contact Problem with Normal Compliance

Abstract

Several discontinuous Galerkin (DG) methods are introduced for solving a frictional contact problem with normal compliance, which is modeled as a quasi-variational inequality. Consistency, boundedness, and stability are established for the DG methods. Two numerical examples are presented to illustrate the performance of the DG methods.