Fephen/Y复合材料的制备、表征及其催化性能

近年来,采用在分子筛孔腔中组装或封装金属配合物的方法制备金属配合物/分子筛复合催化材料的研究引起了人们极大的兴趣.     

剪切作用下马来酸酐接枝乙烯-辛烯共聚物和乙烯-丙烯酸丁酯-甲基丙烯酸缩水甘油酯共聚物对PA1010/PP共混物的增容作用比较

采用熔体共混的方法制备了两种增容剂增容的聚酰胺1010/聚丙烯(PA1010/PP)共混物,通过扫描电镜(SEM)、力学性能和差示扫描量热(DSC)测试,对动态保压注射成型(动态)和普通注射成型(静态)中增容剂POE-g-MAH(马来酸酐接枝乙烯-辛烯共聚物)和PTW(乙烯-丙烯酸丁酯-甲基丙烯酸缩水甘油酯共聚物)对PA1010/PP共混物的增容作用进行了比较研究.研究结果表明,普通注射成型中,PTW增容体系具有更小的分散相粒子,在DSC测试中出现两个结晶峰,即出现异相成核结晶和均相成核结晶,具有更好的拉伸和冲击性能,增容作用更佳.动态保压注射成型中施加剪切可以提高所有共混物的拉伸强度、拉伸模量和缺口冲击强度,PTW和POE-g-MAH两种增容剂增容体系冲击性能相近,但POE-g-MAH增容体系的分散相相区尺寸减小明显、分布均匀性显著增加,材料冲击强度增加幅度更大,表明剪切更有利于POE-g-MAH增容作用的进行.两种增容剂增容作用的不同源于它们化学组成的不同引起的材料形态差别.     

Proteomics Dissection of Cold Responsive Proteins Based on PEG Fractionation in Arabidopsis

Proteome profiling was performed on Arabidopsis plant exposed to cold stress at 4 ℃ for 24 h in an attempt to explore the mechanisms of plant climate adaptation.The polyethylene glycol（PEG） fractionation protocol developed in this lab was used to identify as many differentially expressed low-abundance proteins as possible.In comparison with those of the biological controls,67 protein spots with at least two-fold difference in expression were identified for the plant exposed to cold temperatures; and from these spots,50 proteins were successfully identified by matrix-assisted laser desorption/ionization time of flight mass spectrometry（MALDI-TOF MS）.Bioinformatics studies on these proteins show that 57.8％ of these proteins were localized in the chloroplast.Of these proteins,8 ones have functions in photosynthesis,including glycine hydroxymethyltransferase,Rubisco large subunit,Rubisco activase,PSBO2,fructose-1,6-bisphosphate aldolase,NADP-dependent malate dehydrogenase,sedoheptulose bisphosphatase and photosystem Ⅱ reaction center PsbP family protein,suggesting that photosynthesis is greatly affected by cold stress.The identified proteins were validated by quantitative real-time polymerase chain reaction（qPCR）.Taken together,our results suggest that the chloroplast might also act as a cold stress sensor and that photosynthesis-related proteins may play important roles in cold acclimation for Arabidopsis.     

Substituent effect on the luminescent properties of a series of deep blue emitting mixed ligand Ir(III) complexes

The syntheses of the bright deep blue emitting mixed ligand Ir(III) complexes comprising two cyclometalating, one phosphine and one cyano, ligands are reported. In this study, a firm connection between the nature of the excited states and the physicochemical behavior of the complexes with different ligand systems is elucidated by correlating the observed crystal structures, spectroscopic properties, and electrochemical properties with the theoretical results obtained by the density functional theory (DFT) methods. The cyclometalating ligands used here are the anions of 2-(4',6'-difluorophenyl)-pyridine (F2ppy), 2-(4',6'-difluorophenyl)-4-methyl pyridine (F2ppyM), and 4-amino-2-(4',6'-difluorophenyl)-pyridine (DMAF2ppy). The phosphine ligands are PhP(O-(CH2CH2O)3-CH3)2 and Ph2P(O-(CH2CH2O)n-CH3), where Ph = phenyl and n = 1 (P1), 3 (P3), or 8 (P350). The thermal stabilities of the complexes were enhanced upon increasing the "n" value. The crystal structures of the complexes, [(DMAF2ppy)2Ir(P1)CN], (P1)DMA, and [(F2ppyM)2Ir(P3)CN], (P3)F2M, show the cyano and phosphine groups being in a cis configuration to each other and in a trans configuration to the coordinating Cring atoms. The long Ir-Cring bond lengths are ascribed to the trans effect of the strong phosphine and cyano ligands. DFT calculations indicate that the highest occupied molecular orbital (HOMO) is mainly contributed from the d-orbitals of the iridium atom and the pi-orbitals of cyclometalating and cyano ligands, whereas the lowest unoccupied molecular orbital (LUMO) spreads over only one of the cyclometalating ligands, with no contribution from phosphine ligands to both frontier orbitals. Dimethylamino substitution increases the energy of the emitting state that has more metal-to-ligand-charge-transfer (MLCT) character evidenced by the smaller vibronic progressions, smaller difference in the 1MLCT and 3MLCT absorption wavelengths, and higher extinction coefficients (epsilon) than the F2ppy and F2ppyM complexes. However, the increase in the basicity of the dimethylamino group in the DMAF2ppy complexes in the excited states leads to distortions and consequent nonradiative depopulation of the excited states, decreasing their lower photoluminescence (PL) efficiency. The effect of the substituents in the phosphine ligand is more pronounced in the electroluminescence (EL) than in the PL properties. Multilayer organic light emitting devices (OLEDs) are fabricated by doping the Ir(III) complexes in a blend of mCP (m-bis(N-carbazolyl benzene)) and polystyrene, and their device characteristics are studied. The (P3)F2M complex shows a maximum external quantum efficiency (etaex) of 2%, a maximum luminance efficiency (etaL) of 4.13 cd/A at 0.04 mA/cm2, and a maximum brightness of 7200 cd/m2 with a shift of the Commission Internationale de L'Eclairage (CIE) coordinates from (0.14, 0.15) in film PL to (0.19, 0.34) in EL.     

Synthesis and photophysical properties of water-soluble sulfonato-Salen-type Schiff bases and their applications of fluorescence sensors for Cu in water and living cells

A series of water-soluble sulfonato-Salen-type ligands derived from different diamines including 1,2-ethylenediamine (Et-1–Et-4), 1,2-cyclohexanediamine (Cy-1 and Cy-2), 1,2-phenylenediamine (Ph-1–Ph-3 and PhMe-1–PhMe-4), and dicyano-1,2-ethenediamine (CN-1) has been designed and prepared. Sulfonate groups of ligands ensure good stability and solubility in water without affecting their excited state properties. These ligands exhibit strong UV/Vis-absorption and blue, green, or orange fluorescence. Time-dependent-density functional theory calculations have been undertaken to reveal the influence of ligand nature, especially sulfonate groups, on the frontier molecular orbitals. Since their fluorescence is selectively quenched by Cu²⁺, the sulfonato-Salen-type ligands can be used as highly selective and sensitive turn-off fluorescence sensors for the detection of Cu²⁺ in water and fluorescence imaging in living cells.     

A Comparison of Phenolic Monomers Produced from Different Types of Lignin by Phosphotungstic Acid Catalysts

Herein we studied the chemical structure of different types of lignin samples and the potential to prepare phenolic monomers was illustrated by phosphotungstic acid catalysts. Different types of H/G/S lignin components had different structures. The lignin extracted from poplar had the highest molecular weight and β-O-4 aryl ether contents, followed by pine and straw lignin samples. After depolymerization by PTA catalyst, the yields of phenolic monomers detected was 8.06 wt % (poplar), 5.44 wt % (pine) and 4.52 wt % (straw), respectively. Further, the ratios of H/G/S in the phenol monomers were also different, indicating that the S, G and H types structural units were continuously transformed with each other during the reaction. In our study, the change in the types of lignin samples resulted into an improvement of the distribution of phenolic products, and also the selectivity of phenolic monomers significantly.     

航天柔性结构振动控制的若干新进展

围绕航天柔性结构的振动控制，从结构及材料的数学模型、材料及器件、基本理论与方法和一体化振动控制几个方面对一些研究的最新进展进行了介绍．主动控制和被动控制的一体化技术研究是当今航天柔性结构振动控制研究的重点，两种控制方法的结合不仅优点互补，而且提高了控制系统的性能．控制用材料和器件的研究在工程应用的推动下，也取得了较快的发展，并促进了振动控制技术的实用化     

Highly active and stable porous polymer heterogenous catalysts for decomposition of formic acid to produce H2

Formic acid (FA) has attracted extensive attention as a hydrogen storage material. Here, we develop two heterogeneous catalysts based on porous organic polymers (POPs). After loading the Ru species, the catalyst bearing the triphenylphosphine ligand showed excellent performance in terms of activity and stability for the decomposition of FA to produce hydrogen.     

Protocells programmed through artificial reaction networks

As the smallest unit of life, cells attract interest due to their structural complexity and functional reliability. Protocells assembled by inanimate components are created as an artificial entity to mimic the structure and some essential properties of a natural cell, and artificial reaction networks are used to program the functions of protocells. Although the bottom-up construction of a protocell that can be considered truly ‘alive’ is still an ambitious goal, these man-made constructs with a certain degree of ‘liveness’ can offer effective tools to understand fundamental processes of cellular life, and have paved the new way for bionic applications. In this review, we highlight both the milestones and recent progress of protocells programmed by artificial reaction networks, including genetic circuits, enzyme-assisted non-genetic circuits, prebiotic mimicking reaction networks, and DNA dynamic circuits. Challenges and opportunities have also been discussed.

In this review, the milestones and recent progress of protocells programmed by various types of artificial reaction networks are highlighted.