Employing high-yield production of layered materials by liquid-phase exfoliation, molybdenum disulfide (MoS2) dispersions with large populations of single and few layers were prepared. Electron microscopy verified the high quality of the two-dimensional MoS2 nanostructures. Atomic force microscopy analysis revealed that ~39% of the MoS2 flakes had thicknesses of less than 5 nm. Linewidth and frequency difference of the E(1)2g and A1g Raman modes confirmed the effective reduction of flake thicknesses from the bulk MoS2 to the dispersions. Ultrafast nonlinear optical (NLO) properties were investigated using an open-aperture Z-scan technique. All experiments were performed using 100 fs pulses at 800 nm from a mode-locked Ti:sapphire laser. The MoS2 nanosheets exhibited significant saturable absorption (SA) for the femtosecond pulses, resulting in the third-order NLO susceptibility Imχ((3)) ~ 10(-15) esu, figure of merit ~10(-15) esu cm, and free-carrier absorption cross section ~10(-17) cm(2). Induced free carrier density and the relaxation time were estimated to be ~10(16) cm(-3) and ~30 fs, respectively. At the same excitation condition, the MoS2 dispersions show better SA response than the graphene dispersions.

Sulfide solid electrolytes possess high ionic conductivity and moderate dendrite suppression capability, but rather poor compatibility against oxide cathodes and metallic Li. Here, we report O-doped Li 6 PS 5 Br as solid electrolyte synthesized by a facile solid-state sintering. Different from other O-incorporated sulfides, the O atoms in Li 6 PS 5-x O x Br prefer to substitute the S atoms at free S 2− sites rather than those at the PS 4 tetrahedra. Remarkably, without deteriorating the ionic conductivity, this inorganic solid electrolyte with O doping exhibits comprehensively enhanced properties including excellent dendrite suppression capability, superior electrochemical and chemical stability against Li metal as well as high voltage oxide cathodes, and good air stability. Li(Ni 0.8 Co 0.1 Mn 0.1)O 2 and LiCoO 2-based all-solid-state batteries with Li 6 PS 4.7 O 0.3 Br electrolyte deliver high specific capacity, superior rate capability, and outstanding cycling stability accompanied with low interfacial resistivity. This type of inorganic solid electrolytes is promising for all-solid-state batteries with high energy density.

We demonstrate, for the first time to the best of our knowledge, fabrication of three-dimensional microfluidic channels with arbitrary lengths and configurations inside glass by femtosecond laser direct writing. The main fabrication process includes two steps: (1) direct formation of hollow microchannels in a porous glass substrate immersed in water by femtosecond laser ablation and (2) postannealing of the glass substrate at ∼1150°C by which the porous glass can be consolidated. We show that a square-wavelike channel with a total length of ∼1.4 cm and a diameter of ∼64 μm can be easily produced ∼250 μm beneath the glass surface.

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2014Medium-range order in sol-gel prepared Al2O3-SiO2 glasses: new results from solidstate NMR Journal of Physical Chemistry C,Washington, DC : American Chemical Society - ACS,v. 118, n. 9, p. 4906-4917, Feb. 2014 Al} rotational echo adiabatic passage double-resonance (REAPDOR) spectroscopy. To boost the signal-to-noise ratio, the REAPDOR experiment was combined with a Carr−Purcell− Meiboom−Gill (CPMG) echo train acquisition. While all five silicon units Q (4) mAl (0 ≤ m ≤ 4) are detectable in appreciable concentrations for x = 1, the spectra indicate that the average number of Al species bound to silicon, ⟨m Al ⟩, gradually decreases toward higher x values, as expected. The 27 Al MAS NMR spectra reveal four-, five-, and six-coordinated aluminum in these glasses. For x ≥ 3, the Al species detected are essentially independent of sample composition indicating a constant structural environment of Al. In contrast, for x = 1 and 2, an increase in the 27 Al isotropic chemical shifts suggests an increasing number of Al···Al proximities. Consistent with this finding, two-dimensional 27 Al− 27 Al double-quantum/ single-quantum correlation spectroscopy reveals spatial proximities among and between all types of aluminum species present. On the basis of the complementary evidence from these single-and double-resonance experiments, a model for the mediumrange order of these glasses is developed.

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As a popular exercise form, Tai Chi (TC) has been investigated to determine its contributions to an active and healthy lifestyle. There are an increasing number of researchers who focus on exploring the potential physiological and psychological benefits of TC but only a few systematic reviews of these benefits to a variety of populations. The purpose of this paper is to comprehensively evaluate the reported psychological benefits associated with practicing TC. Although many investigators have reported possible psychological benefits of TC for children, young adults, older healthy adults, and for a variety of patient populations, many of the reports suffer one or more methodological flaws. These flaws include inadequate study design, including lack of control groups, small sample sizes, unsophisticated statistical techniques, or publication without rigorous peer review. After reviewing the results of the existing literature regarding the potential psychological benefits of TC, we recommend that future investigations be conducted with additional adherence to the traditional scientific process.

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