几种新的四苯(基)苯基有机硅化合物的研究

本工作以双乙烯基四甲基二硅氧烷、乙烯基甲基二氯硅烷、乙烯基七甲基环四硅氧烷分别与四苯基环戊二烯酮通过Diels-Alder反应合成了相应的四种四苯(基)苯基有机硅化合物(Ⅰ-Ⅳ)。并由化合物Ⅲ又制成了三种化合物Ⅴ一Ⅶ。对这些新化合物的组成、结构作了相应的分析、测试和鉴定。还对有些Diels-Alder反应做了改进,从封管反应改为常压反应后,效果更佳。     

参量阵差分Pattern时延差编码冰下水声通信方法

为提高差分Pattern时延差编码水声通信方法的通信速率以及抗多途能力,使其能有效适用于冰下水声环境,提出了基于参量阵的差分Pattern时延差编码水声通信方法,推导了Pattern码的参量发射原理,分析了参量阵发射对该方法性能的影响,利用参量阵发射产生低频宽带窄指向性声柬,减少了声线触碰上下边界的次数,提高了系统抗多途的能力。冰下水域外场试验结果表明:本方法可有效抑制多途效应,同时低频宽带特性提高了系统通信速率。     

A Self‐Supporting Strategy for Gas‐Phase and Slurry‐Phase Ethylene Polymerization using Late‐Transition‐Metal Catalysts

The polyolefin industry is dominated by gas‐phase and slurry‐phase polymerization using heterogeneous catalysts. In contrast, academic research is focused on homogeneous systems, especially for late‐transition‐metal catalysts. The heterogenization of homogeneous catalysts is a general strategy to provide catalyst solutions for existing industrial polyolefin synthesis. Herein, we report an alternative, potentially general strategy for using homogeneous late‐transition‐metal catalysts in gas‐phase and slurry‐phase polymerization. In this self‐supporting strategy, catalysts with moderate chain‐walking capabilities produced porous polymer supports during gas‐phase ethylene polymerization. Chain walking, in which the metal center can move up and down the polymer chain during polymerization, ensures that the metal center can travel along the polymer chain to find suitable sites for ethylene enchainment. This strategy enables simple heterogenization of catalysts on solid supports for slurry‐phase polymerization. Most importantly, various branched ultra‐high‐molecular‐weight polyethylenes can be prepared under various polymerization conditions with proper catalyst selection.     

In situ synthesis of Cu2O nano/microstructures on a copper substrate assisted with mixed cationic/anionic surfactants

Different morphologies of Cu₂O nano/microstructures have been successfully prepared on copper foil via a mild hydrothermal process in the presence of mixed cationic/anionic surfactants, by using copper foil to serve as both copper source and substrate. The reaction system of mixed cationic/anionic surfactants and the reaction temperature play key roles in the formation of different morphologies of Cu₂O nano/microstructures. X-ray diffraction (XRD), field emission scanning electron microscope (SEM), transmission electron microscope (TEM), selected area electron diffraction (SAED) and room temperature photoluminescence (PL) spectra are used to characterize the as-obtained products. The PL results confirmed that the Cu₂O structures exhibited good optical properties. A reasonable formation mechanism was proposed based on the experimental results.     

Ring‐Closing Metathesis on an Allyl‐Terminated Carbosilane Dendrimer

Grubbs' catalyst was used to prepare a series of carbosilane dendrimers with silacyclopentene peripheral groups, suitable for further elaboration to functional dendrimers. The efficiency of the ring closing metathesis reaction was found to be strongly dependent on the reaction temperature and the amount of catalyst used, as shown by ¹H NMR monitoring.     

Luminescent organo‐polysiloxanes containing complexed lanthanide ions

In this study, a type of polysiloxane with the ester as the functional side group was prepared via a hydrosilylation reaction. The functionalized polysiloxane was then allowed to complex with Tb³⁺ and Eu³⁺ ions. Fourier transform infrared, ultraviolet absorption spectra and ¹H‐NMR, ¹³C‐NMR and ²⁹Si‐NMR spectra were used to confirm the modification. Differential scanning calorimetry and thermal gravity analysis were used to study the polysiloxane's thermal properties. The complexes' luminescence spectra were recorded, and narrow‐width green and red emissions were achieved. Copyright © 2009 John Wiley & Sons, Ltd.     

Theoretical study on the interaction of sulfur‐ and aminopyridine‐containing chelating resins with Hg(II) and Pb(II)

The geometries and energetics of complexes of Hg(II) and Pb(II) with sulfur‐ and aminopyridine‐containing chelating resin including crosslinked polystyrene immobilizing 2‐aminopyridine via sulfur‐containing (PVBS‐AP), sulfoxide‐containing (PVBSO‐AP), and sulfone‐containing (PVBSO₂‐AP) spacer arms have been investigated theoretically, and thus interactions of the metal ions with chelating resins were evaluated. The results indicate that PVBS‐AP behaves as a tridentate ligand to coordinate with the metal ions by S and two N atoms to form chelating compounds with S atom playing a dominant role in the coordination, whereas PVBSO‐AP and PVBSO₂‐AP interact with metal cations, respectively, in a tricoordinate manner by O and two N atoms forming chelating complexes. Furthermore, it is revealed that O and N2 atoms of PVBSO‐AP are the main contributor of coordination to Hg(II), whereas N2 atom of PVBSO₂‐AP is mainly responsible for the coordination to Hg(II). For PVBSO‐AP‐Pb²⁺ and PVBSO₂‐AP‐Pb²⁺ complex, the coordination is dominated by the synergetic effect of N1, N2, and O atoms. Natural bond orbital and second‐order perturbation analyses suggest that the charge transfer from the chelating resins to metal ions is mainly dominated by the interactions of lone pair of electrons of the donor atoms with the unoccupied orbitals of metal ions. Hg(II) complexes exhibit larger binding energies than the corresponding Pb(II) complexes, implying the chelating resins exhibit higher affinity toward Hg(II), which is consistent with the experimental results. Combined the theoretical and experimental results, further understanding of the structural information of the complexes and the coordination mechanism was achieved. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2011     

Direct growth of silver nanostructures on zinc substrate by a modified galvanic displacement reaction

This paper reports a modified galvanic displacement approach for the synthesis of Ag nanostructures with different morphologies. During the process, AgNO₃ as starting material is reduced using zinc foil and this is followed by suitable thermal treatment. The reaction time, concentration of the AgNO₃ aqueous solutions and thermal treatment temperature directly influence the morphologies of Ag nanostructures. X-ray diffraction (XRD), field emission scanning electron microscopy (SEM), transmission electron microscopy (TEM), selected area electron diffraction (SAED), and UV–visible spectra are used to characterize the products obtained. Furthermore, a representative experiment using rhodamine (R6G) as the probe molecule confirms that the Ag nanostructure shows strong surface-enhanced Raman scattering (SERS) activity.     

化爆引起的电磁辐射

对带金属壳装药爆炸产生的电磁辐射进行了一系列实验研究。运用量纲分析方法，初步给出了电磁辐射与爆炸动力学参量之间的关系。     

WPU/Cu2-XSe coated cotton fabrics for photothermal conversion and photochromic applications

Cellulose - Multifunctional cotton fabrics were fabricated by coating of anionic waterborne polyurethane (WPU)/Cu2-XSe. The surface morphology of WPU/Cu2-XSe coated cotton fabric was characterized...