Flame synthesis of few-layered graphene/graphite films

We report a fast (in 10-40 s) flame synthesis of high quality few-layered graphene/graphite films, offering the advantages of simplicity, high efficiency, energy saving, low cost and the ability to extend to continuous and mass production of graphene.     

A "turn-on" fluorescent probe for hypochlorous acid: convenient synthesis, good sensing performance, and a new design strategy by the removal of C=N isomerization

A new design strategy for the development of fluorescent turn-on chemodosimeters toward OCl(-) was proposed by the removal, but not the general inhibition, of the C=N isomerization. Accordingly, Flu-1 was prepared, which, as shown in the fluorescent picture, exhibited the off-on response for OCl(-), sensitively and selectively.     

Imidazole-modified porphyrin as a pH-responsive sensitizer for cancer photodynamic therapy

5,10,15,20-Tetrakis(N-(2-(1H-imidazol-4-yl)ethyl)benzamide)porphyrin produced twice as many singlet oxygen ((1)O(2)) molecules at pH 5.0 (quantum yield 0.53 ± 0.01) than at pH 7.4, whereas the (1)O(2) quenching rate was reduced by a factor of 2.5 for a pH change from 7.4 to 5.0.     

Theoretical insight into the electronic, optical and photocatalytic properties of InMO4 (M = V, Nb, Ta) photocatalysts

The electronic and optical properties of InMO(4) (M = V, Nb, Ta) photocatalysts are studied using first-principles calculations. For all InMO(4), the calculated band gaps are larger than the measured optical gaps, indicating the existence of sub-bandgap transitions. Impurity states and excitons are considered to interpret the characteristic absorption onsets in the measured UV-visible diffuse reflection spectra. The novel visible-light-active water-splitting photocatalytic properties of InMO(4) are related to the sub-bandgap transitions. Correlation between the impurity states and the photocatalytic activities is discussed for InMO(4)via the conventional mechanism of photocatalytic water-splitting on semiconductors. An excitonic mechanism analogous to Photosystem II in plant photosynthesis is also proposed for the photocatalytic water-splitting process on InMO(4).     

Gold(I)‐Catalyzed Enantioselective Intermolecular Hydroarylation of Allenes with Indoles and Reaction Mechanism by Density Functional Theory Calculations

Chiral binuclear gold(I) phosphine complexes catalyze enantioselective intermolecular hydroarylation of allenes with indoles in high product yields (up to 90 %) and with moderate enantioselectivities (up to 63 % ee). Among the gold(I) complexes examined, better ee values were obtained with binuclear gold(I) complexes, which displayed intramolecular Au^I Au^I interactions. The binuclear gold(I) complex 4c [(AuCl)₂( L3 )] with chiral biaryl phosphine ligand (S)‐(−)‐MeO‐biphep ( L3 ) is the most efficient catalyst and gives the best ee value of up to 63 %. Substituents on the allene reactants have a slight effect on the enantioselectivity of the reaction. Electron‐withdrawing groups on the indole substrates decrease the enantioselectivity of the reaction. The relative reaction rates of the hydroarylation of 4‐X‐substituted 1,3‐diarylallenes with N‐methylindole in the presence of catalyst 4c [(AuCl)₂( L3 )] / AgOTf [ L3 =(S)‐(−)‐MeO‐biphep], determined through competition experiments, correlate (r²=0.996) with the substituent constants σ. The slope value is −2.30, revealing both the build‐up of positive charge at the allene and electrophilic nature of the reactive Au^I species. Two plausible reaction pathways were investigated by density functional theory calculations, one pathway involving intermolecular nucleophilic addition of free indole to aurated allene intermediate and another pathway involving intramolecular nucleophilic addition of aurated indole to allene via diaurated intermediate E2 . Calculated results revealed that the reaction likely proceeds via the first pathway with a lower activation energy. The role of Au^I Au^I interactions in affecting the enantioselectivity is discussed.     

Global mild solutions of Navier‐Stokes equations

We establish a global well‐posedness of mild solutions to the three‐dimensional, incompressible Navier‐Stokes equations if the initial data are in the space ${\cal{X}}^{-1}$ defined by \input amssym ${\cal{X}}^{‐1} = \{f \in {\cal{D}}^\prime(R^3): \int_{{\Bbb{R}}^3}|\xi|^{‐1}|\widehat{f}|d\xi < \infty\}$ and if the norms of the initial data in ${\cal{X}}^{-1}$ are bounded exactly by the viscosity coefficient μ. © 2010 Wiley Periodicals, Inc.     

延误休假且修理延迟的可修系统的更换策略

研究了修理工多重延误休假且修理延迟的可修系统,假设系统故障后均不能"修复如新",系统在准备休假期间故障的概率为q,系统延迟修理的概率为1-P,以系统故障次数为更换策略,运用更新过程和几何过程理论,得出系统长期运行单位时间内平均停机时间的表达式,并通过数值例子验证了存在最优策略,使得平均停机时间最短.     

Gorenstein正则环、奇点范畴和Ding模

本文证明了任意环的整体Ding投射维数和整体Ding内射维数一致,研究了奇点范畴和相对于Ding模的稳定范畴间的关系,并刻画了Gorenstein (正则)环以及环的整体维数的有限性.