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As already stated by CN09, we agree with P09 thatthere is not enough evidence to unambiguously conclude that NAT-like layers in CN09 are actually composed of NATcrystals. Mixtures of liquid aerosols and ice, as proposed byP09, app...
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As already stated by CN09, we agree with P09 thatthere is not enough evidence to unambiguously conclude that NAT-like layers in CN09 are actually composed of NATcrystals. Mixtures of liquid aerosols and ice, as proposed byP09, appear as a convincing possibility. As mentioned byCN09, other potential candidates include very small, non-spherical ice crystals that have been observed in situ insignificant concentrations [Gayet et al., 2007]; it remains tobe seen if such particles are thermodynamically stable in thespecific conditions of the TTL. However, this reply tries toshow why we also think that it is too soon to defmitely ruleout a NAT composition for the non-ice/non-liquid layers inCALIOP TTL observations. More studies, including remotesensing and in-situ observations, are required to fullyresolve these questions.
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The recent paper by Chepfer and Noel [2009] (here-inafter referred to as CN09), analyzed measurements ofclouds in the tropical tropopause layer (TTL) by the lidaronboard the CALIPSO (Cloud-Aerosol Lidar and InfraredPathfinder Sate...
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The recent paper by Chepfer and Noel [2009] (here-inafter referred to as CN09), analyzed measurements ofclouds in the tropical tropopause layer (TTL) by the lidaronboard the CALIPSO (Cloud-Aerosol Lidar and InfraredPathfinder Satellite Observations) spacecraft. CN09 con-cluded that about 20% of the CALIPSO TTL cloud data hadthe optical characteristics of nitric acid trihydrate (NAT),and that NAT-like particles covered the entire tropical belt.Some earlier spaceborne observations of clouds in the TTLwere also interpreted as evidence of NAT, for example,backscatter data from the Lidar-In Space TechnologyExperiment (LITE) [Omar and Gardner, 2001] and extinc-tion data from the Halogen Occultation Experiment(HALOE) [Hervig and McHugh, 2002]. These earlier inter-pretations were challenged by Jensen and Drdla [2002](hereinafter referred to as JD02), whose Mie calculationsindicated there is insufficient HNO_3in the TTL to explainthe observed HALOE optical signature in terms of NATparticles. Furthermore, JD02 suggested that the observedwavelength dependence of LITE TTL cloud data could beexplained by a mixture of liquid aerosols and optically thincirrus, which produces an optical signature that could bemisinterpreted as small NAT particles.
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Being confronted with the energy crisis and environmental problems, the exploration of clean and renewable energy materials as well as their devices are urgently demanded. Two-dimensional (2D) atomically-thick materials, graphene ...
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Being confronted with the energy crisis and environmental problems, the exploration of clean and renewable energy materials as well as their devices are urgently demanded. Two-dimensional (2D) atomically-thick materials, graphene and graphene-like layered transition metal dichalcogenides (TMDs), have showed vast potential as novel energy materials due to their unique physicochemical properties. In this Review, we outline the typical application of graphene and grpahenelike TMDs in energy conversion and storage fields, and hope to promote the development of 2D TMDs in this field through the analysis and comparisons with the relatively natural graphene. First, a brief introduction of electronic structures and basic properties of graphene and TMDs are presented. Then, we summarize the exciting progress of these materials made in both energy conversion and storage field including solar cells, electrocatalysis, supercapacitors and lithium ions batteries. Finally, the prospects and further developments in these exciting fields of graphene and graphene-like TMDs materials are also suggested.
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In this paper we deal with the investigation of the thin diamond-like layers (DLC) manufactured on magnesium alloys (AZ31) using Plasma Activated Chemical Vapour Deposition (PACVD) method. Raman spectroscopy investigation has been...
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In this paper we deal with the investigation of the thin diamond-like layers (DLC) manufactured on magnesium alloys (AZ31) using Plasma Activated Chemical Vapour Deposition (PACVD) method. Raman spectroscopy investigation has been carried out for determining both layer composition and fraction of the diamond-like structure in the layers. The Raman spectroscopy is recognized as the main tool used for surveying of the allotropic content of the carbon layers. It is imposed by the necessity of the distinction not among the different chemical elements but among different bonds of the same chemical element-carbon, or alternatively-among different bonds of carbon with a few other chemical elements-especially hydrogen. During the Raman spectra analysis, both qualitative and quantitative analysis are performed, which is essential for the use of the carbon coatings in the broad range of mechanical technologies. A tool used in these investigations is Voigt peak profile based on Faddeeva function, allowing a very precise comparison of spectra with elimination of specificity of measurement equipment.
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Flower-like Li_(1.2)Ni_(0.17)Co_(0.17)Mn_(0.5)O_2 microstructures were prepared by a simple one step low-tempcraturc electrospinning method. The morphological changes occurred with temperature increase from 500 °C to 700 °C. Sca...
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Flower-like Li_(1.2)Ni_(0.17)Co_(0.17)Mn_(0.5)O_2 microstructures were prepared by a simple one step low-tempcraturc electrospinning method. The morphological changes occurred with temperature increase from 500 °C to 700 °C. Scanning electron microscopy showed that flowcr-likc Li_(1.2)Ni_(0.17)Co_(0.17)Mn_(0.5)O_2 after heat treatment at 600 °C was composed of nanoplates with an open porous structure. Flower-like electrode with well-organized porous structure can be attributed to the favorable shape to facilitate the diffusion of lithium ions. Flower-like Li_(1.2)Ni_(0.17)Co_(0.17)Mn_(0.5)O_2 microstructures showed a high discharge capacity of 235 mA h g~(-1) during the first cycle compared to other electrode materials.
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Two-dimensional (2D) "graphene-like" inorganic materials, because of the short lithium ion diffusion path and unique 2D carrier pathways, become a new research focus of the lithium storages. Some "graphene-like" binary compounds, ...
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Two-dimensional (2D) "graphene-like" inorganic materials, because of the short lithium ion diffusion path and unique 2D carrier pathways, become a new research focus of the lithium storages. Some "graphene-like" binary compounds, such as, MnO2, MoS2 and VO2 ultrathin nanosheets, have been synthesized by the peeling method, which also exhibit enhanced lithium storage performances. However, it still remains a great challenge to synthesize widely-used lithium-containing ternary oxides with "graphene-like" nanostructures, because the lithium-containing ternary oxides, unlike ternary layered double hydroxides (LDH), are very hard to be directly peeled. Herein, we successfully synthesized ultrathin Li3VO4 nanoribbons with a thickness of about 3 nm by transformation from ultrathin V2O5 xH(2)O nanoribbons, moreover, we achieved the preparation of ultrathin Li3VO4 nanoribbon@graphene sandwich-like nanostructures (LVO/G) through the layer-by-layer assembly method. The unique sandwich-like nanostructures shows not only a high specific reversible capacitance (up to 452.5 mA h g(-1) after 200 cycles) but also an excellent cycling performance (with more than 299.2 mA h g(-1) of the capacity at 10C after 1000 cycles) as well as very high rate capability. Such template strategy, using "graphene-like" binary inorganic nanosheets as templates to synthesize lithium-containing ternary oxide nanosheets, may be extended to prepare other ternary oxides with "graphene-like" nanostructures. (C) 2015 Elsevier Ltd. All rights reserved.
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Schwertmannite (sch), an iron oxyhydrosulfate mineral, can catalyse a Fenton-like reaction to degrade organic contaminants, but the reduction of Fe(III) to Fe(II) on the surface of schwertmannite is a limiting step for the Fenton-...
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Schwertmannite (sch), an iron oxyhydrosulfate mineral, can catalyse a Fenton-like reaction to degrade organic contaminants, but the reduction of Fe(III) to Fe(II) on the surface of schwertmannite is a limiting step for the Fenton-like process. In the present study, the sch/few-layer graphene (sch–FLG) composite was synthesized to promote the catalytic activity of sch in a Fenton-like reaction. It was found that sch can be successfully carried by FLG in sch–FLG composite, mainly via the chemical bond of Fe–O–C on the surface of sch–FLG. The sch–FLG exhibited a much higher catalytic activity than sch or FLG for the degradation of sulfamethazine (SMT) in the heterogeneous Fenton-like reaction, which resulted from the fact that the FLG can pass electrons efficiently. The degradation efficiency of SMT was around 100% under the reaction conditions of H 2 O 2 200–500 mg l ?1 , sch–FLG dosage 1–2 g l ?1 , temperature 28–38°C, and initial solution pH 1–9. During the repeated uses of sch–FLG in the Fenton-like reaction, it maintained a certain catalytic activity for the degradation of SMT and the mineral structure was not changed. In addition, SMT may be finally mineralized in the Fenton-like reaction catalysed by sch–FLG, and the possible degradation pathways were proposed. Therefore, the sch–FLG is an excellent catalyst for SMT degradation in a heterogeneous Fenton-like reaction.
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This study investigated the effects of the electric potential of a surface on the lubricating capabilities of ionic liquids. The friction coefficient of 1-butyl-3-methylimidazolium iodide was unchanged by the electric potential of...
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This study investigated the effects of the electric potential of a surface on the lubricating capabilities of ionic liquids. The friction coefficient of 1-butyl-3-methylimidazolium iodide was unchanged by the electric potential of the surface because this ionic liquid has difficulty moving in a solution owing to its low conductivity. However, the friction coefficient, when lubricated with 1-butyl-3-methylimidazolium tris(pentafluoroethyl)trifluorophosphate and 1-butyl-3-methylimidazolium hexafluorophosphate, changed when the electric potential of the surface was varied. At -2.0 V, cations were adsorbed on the sliding surface. The alkyl chain of cations supported the load and achieved a low friction coefficient. However, at 2.0 V, anions were adsorbed on the sliding surface. Such ions cannot support the load, and thus reach a high friction coefficient.
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Here we report for the first time the design and expression of highly charged, unfolded protein polymers based on elastin-like peptides (ELPs). Positively and negatively charged variants were achieved by introducing lysine and glu...
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Here we report for the first time the design and expression of highly charged, unfolded protein polymers based on elastin-like peptides (ELPs). Positively and negatively charged variants were achieved by introducing lysine and glutamic acid residues, respectively, within the repetitive pentapeptide units. Subsequently it was demonstrated that the monodisperse protein polyelectrolytes with precisely defined amino acid compositions, sequences, and stereochemistries can be transferred into superstructures exploiting their electrostatic interactions. Hollow capsules were assembled from oppositely charged protein chains by using the layer-by-layer technique. The structures of the capsules were analyzed by various microscopy techniques revealing the fabrication of multilayer containers. Due to their low toxicity in comparison to other polyelectrolytes, supercharged ELPs are appealing candidates for the construction of electrostatically induced scaffolds in biomedicine.
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The creation of intergrown layer-like zeolite crystals is one route to form hierarchical zeolites. Faujasite-type (FAU-type) zeolites are among the industrially most important zeolites and the implementation of hierarchical porosi...
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The creation of intergrown layer-like zeolite crystals is one route to form hierarchical zeolites. Faujasite-type (FAU-type) zeolites are among the industrially most important zeolites and the implementation of hierarchical porosity is a promising way to optimise their catalytic and adsorptive performance. After a short general survey into routes for the preparation of hierarchical pore systems in FAU, we will review the currently existing strategies for the synthesis of FAU with layer-like morphology. Those strategies are mainly based on the presence of morphology modifying agents in the synthesis mixture. However, a very recent approach is the synthesis of layer-like FAU-type zeolite crystals assembled in an intergrown manner in the absence of such additives, just by finely adjusting the crystallization temperature. This additive-free preparation route for layer-like FAU, which appears very attractive from an ecological as well as economic point of view, is highlighted in this review. Concluding, a comparison, including powder X-ray diffraction, scanning and transmission electron microscopy, nitrogen physisorption and elemental analysis, between conventional FAU and three layer-like FAU obtained by different synthesis routes was carried out to show the structural, morphological and textural differences and similarities of these materials.
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