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The synthesis of two-dimensional （2D） layered materials with controllable thickness is of considerable interest for diverse applications. Here we report the first chemical vapor deposition growth of single- and few-layer MoSe2 nanosheets. By using Se and MoO3 as the chemical vapor supply, we demonstrate that highly crystalline MoSe2 can be directly grown on the 300 nm SiO2/Si substrates to form optically distinguishable single- and multi-layer nanosheets, typically in triangular shaped domains with edge lengths around 30 btm, which can merge into continuous thin films upon further growth. Micro-Raman spectroscopy and imaging was used to probe the thickness-dependent vibrational properties. Photoluminescence spectroscopy demonstrates that MoSe2 monolayers exhibit strong near band edge emission at 1.55 eV, while bilayers or multi-layers exhibit much weaker emission, indicating of the transition to a direct band gap semiconductor as the thickness is reduced to a monolayer.

The thermal conduction of suspended few-layer hexagonal boron nitride （h-BN） sheets was experimentally investigated using a noncontact micro-Raman spectroscopy method. The first-order temperature coefficients for monolayer （1L）, bilayer （2L） and nine-layer （9L） h-BN sheets were measured to be -（3.41 ± 0.12）× 10-2, -（3.15 ± 0.14） × 10-2 and -（3.78 ±0.16）× 10-2 cm-1.K-1, respectively. The room-temperature thermal conductivity of few-layer h-BN sheets was found to be in the range from 227 to 280 W.m-1-K-1, which is comparable to that of bulk h-BN, indicating their potential use as important components to solve heat dissipation problems in thermal management configurations.

Cost-effective catalysts for the oxidation of volatile organic compounds （VOCs） are critical to energy conversion applications and environmental protection. The main bottleneck of this process is the development of an efficient, stable, and cost-effective catalyst that can oxidize HCHO at low temperature. Here, an advanced material consisting of manganese cobalt oxide nanosheet arrays uniformly covered on a carbon textile is successfully fabricated by a simple anodic electrodeposition method combined with post annealing treatment, and can be directly applied as a high-performance catalytic material for HCHO elimination. Benefiting from the increased surface oxygen species and improved redox properties, the as-prepared manganese cobalt oxide nanosheets showed substantially higher catalytic activity for HCHO oxidation. The catalyst completely converted HCHO to CO2 at temperatures as low as 100 ℃, and exhibited excellent catalytic stability. Such impressive results are rarely achieved by non-precious metal-based catalysts at such low temperatures.

Supercapacitors operating in aqueous solutions are low cost energy storage devices with high cycling stability and fast charging and discharging capabilities, but generally suffer from low energy densities. Here, we grow Ni（OH）2 nanoplates and RuO2 nanoparticles on high quality graphene sheets in order to maximize the specific capacitances of these materials. We then pair up a Ni（OH）2/graphene electrode with a RuO2/graphene electrode to afford a high performance asymmetrical supercapacitor with high energy and power density operating in aqueous solutions at a voltage of -1.5 V. The asymmetrical supercapacitor exhibits significantly higher energy densities than symmetrical RuO2-RuO2 supercapacitors or asymmetrical supercapacitors based on either RuO2- carbon or Ni（OH）2-carbon electrode pairs. A high energy density of -48 W.h/kg at a power density of -0.23 kW/kg, and a high power density of -21 kW/kg at an energy density of N14 W-h/kg have been achieved with our Ni（OH）2/graphene and RuO2/graphene asymmetrical supercapacitor. Thus, pairing up metal-oxide/graphene and metal-hydroxide/graphene hybrid materials for asymmetrical supercapacitors represents a new approach to high performance energy storage.

Lipids exhibit an extraordinary polymorphism in self-assembled mesophases, with lamellar phases as the most relevant biological representative. To mimic lipid lamellar phases with amphiphilic designer peptides, seven systematically varied short peptides were engineered. Indeed, four peptide candidates （V4D, V4WD, V4WD2, I4WD2） readily self-assembled into lamellae in aqueous solution. Small-angle X-ray scattering （SAXS） patterns revealed ordered lamellar structures with a repeat distance of 4-5 nm. Transmission electron microscopy （TEM） images confirmed the presence of stacked sheets. Two derivatives （V3D and V4D2） remained as loose aggregates dispersed in solution; one peptide （L4WD2） formed twisted tapes with internal lameUae and an antiparaUel -type monomer aligrtment. To understand the interaction of peptides with lipids, they were mixed with phosphatidylcholines. Low peptide concentrations （1.1 mM） induced the formation of a heterogeneous mixture of vesicular structures. Large multilamellar vesicles （MLV, d-spacing - 6.3 nm） coexisted with oligo- or unilamellar vesicles （- 50 nm in diameter） and bicelle-like structures （- 45 nm length, - 18 nm width）. High peptide concentrations （11 mM） led to unilamellar vesicles （ULV, diameter - 260-280 nm） with a homogeneous mixing of lipids and peptides. SAXS revealed the temperature-dependent fine structure of these ULVs. At 25 ℃ the bilayer is in a fully Interdigitated state （headgroup-to-headgroup distance dH, -2.9 nm）, whereas at 50 ℃this interdigitation opens up （dtm- 3.6 nm）. Our results highlight the versatility of self-assembled peptide superstructures. Subtle changes in the amino acid composition are key design elements in creating peptide- or lipid- peptide nanostructures with richness in morphology similar to that of naturally occurrin~ lioids.

A double-layer microfluidic chip integrated with a hollow fiber（HF）was developed to reconstitute the intestine-liver functionality for studying the absorption and metabolism of combination drugs.Caco-2 cells were inoculated in the HF cavity at the top of the serpentine channel to simulate the intestinal tissue for drug absorption and transport studied,and Hep G2 cells,seeded in the bottom chamber,were used to mimic the liver for metabolism-related studies.Genistein and dacarbazine were selected for combination drug therapy and its effects on cell viability,hepatotoxicity,and cell cycle arrest under drug-conditioned culture were investigated.The results suggested that the combined concentration below-100μg/m L had no significant inhibitory effect on Hep G2 cell viability,and therefore Hep G2 cells maintained their drug metabolism ability.When the drug concentration was increased above 250μg/m L,Hep G2 cells underwent apoptosis.Detection of metabolites by mass spectrometry proved the effective metabolism in the microchip model.This dynamic,co-culture microchip successfully provided a podium for long-term observation of absorption,transport,and metabolism of combination drugs,and could be an effective in vitro simulation model for further clinical research.

Deposition of clean and defect-free atomically thin two-dimensional crystalline flakes on surfaces by mechanical exfoliation of layered bulk materials has proven to be a powerful technique, but it requires a fast, reliable and non-destructive way to identify the atomically thin flakes among a crowd of thick flakes. In this work, we provide general guidelines to identify ultrathin flakes of TaSe2 by means of optical microscopy and Raman spectroscopy. Additionally, we determine the optimal substrates to facilitate the optical identification of atomically thin TaSe2 crystals. Experimental realization and isolation of ultrathin layers of TaSe2 enables future studies on the role of the dimensionality in interesting phenomena such as superconductivity and charge density waves.

A lithium-assisted approach has been developed for the exfoliation of pristine graphite, which allows the large-scale preparation of few-layer graphene nanosheets. The process involves an unexpected physical insertion and exfoliafion, and the graphene nanosheets prepared by this method reveal undisturbed sp2-hybridized structures. A possible two-step mechanism, which involves the negative charge being trapped around the edges of the graphite layers and a subsequent lithiation process, is proposed to explain the insertion of lithium inside the graphite interlayers. If necessary, the present exfoliation can be repeated and thinner （single or 2-3 layer） graphene can be achieved on a large scale. This simple process provides an efficient process for the exfoliation of pristine graphite, which might promote the future applications of graphene.

Fluorescence resonance energy transfer （FRET） systems have broad applications in visual detection, intelligent materials, and biological imaging, all of which favor the transmission of light through multiple dimensions and in diverse directions. Herein, we have demonstrated multi-dimensional （0D and 2D） FRET within a multi-layer ultrathin film （UTF） by employing a layer-by-layer （LBL） assembly technique. The anionic block copolymer micelle poly（tert-butyl acrylate- co-ethyl acrylate-co-methacrylic acid） （PTBEM） is chosen as a molecular carrier for the incorporation of bis（8-hydroxyquinolate） zinc （Znq2） and open-ring merocyanine （MC） （denoted as （Znq2/MC）@PTBEM）. Alternatively, electrostatic assembly is performed with cationic layered double hydroxide （LDH） nanosheets （denoted as [（Znq2/MC）@PTBEM/LDH]n）. This [（Znq2/MC）@PTBEM/ LDH]n system offers a multi-dimensional propagation medium and ensures that the FRET donor and acceptor are located within their F6rster radii in each direction. The system demonstrates a FRET process that can be switched via alternating ultraviolet/visible （UV/vis） irradiation, with tunable blue-green/red fluorescence, resulting in a FRET efficiency as high as 81.7%. It is expected that this assembly method, which uses 0D micelles on a 2D layered material, can be extended to other systems for further development of multi-dimensional FRET.

A hot-press tackified preform was used to improve the uniformity of the laminates thickness and the mechanical properties of the obtained laminates were studied using vacuum assisted resin transfer molding（VARTM）. Two modified preforms were prepared under 0.1 and 0.6 MPa in an autoclave and then were used to fabricate the laminates via VARTM. Permeability and thickness distribution of the laminates were obtained by using a special device. Moreover, the tensile and compressive strengths of the obtained laminates were studied and compared with the unmodified ones. Results show that the tackified laminates present a maximum and minimum thickness under 0.1 and 0.6 MPa, respectively. The thicknesses and in-plane permeability of the tackified laminates, with better thickness uniformity, are significantly decreased compared with that of the unmodified cases, while the tensile and compressive strengths of the tackified laminates are improved obviously. Results show that the mechanical property of the tackified laminates prepared by hotpressing at 0.1 MPa is better than that processed at 0.6 MPa.