Alexander Smith

TL;DR: In this paper, the authors assess the status of knowledge of binary central stars discovered because of irradiation effects and find that only 9 out of 12 irradiated binaries have periods smaller than 1 day, a fact that is at odds with post-common envelope predictions.

Abstract: DOI: 10.1002/aenm.201400398 r-GO’s 2D nature makes it an excellent template for edgerich MoS x domains. [ 6 ] However, its fl at structure makes it prone to restacking upon deposition from solution, reducing the available electrochemically active area. One approach to address this problem is to isotropically compress the fl at sheets into a crumpled paper ball structure by utilizing the capillary forces present when an aerosol droplet rapidly evaporates. [ 13,14 ] The resulting crumpled graphene particles are remarkably resistant to aggregation because the available surface area for van der Waals attraction between sheets is greatly reduced due to their folded structure. Additionally, the particles are compression resistant because local plastic deformation and inter-sheet Van der Waals bonds stabilize the structures. Thus, like paper balls, crumpled graphene particles can pack into 3D structures with high available surface areas. These crumpled graphene particles have also shown to support or enclose nanoparticles to produce composite materials with new functionalities. [ 15 ] In this work, we use the crumpled graphene particles as a surface area enhancer for a common 3D electrode substrate, carbon cloth (CC), and use them as a graphitic template for the growth of molybdenum sulfi de nanoparticles. Crumpled graphene particles were made by dispersing graphene oxide (GO) in water and crumpling the sheets into balllike particles using an aerosol-assisted process, as detailed in previous work. [ 13 ] Briefl y, the GO dispersion was aerosolized by an ultrasonic atomizer and the droplets were carried by fl owing N 2 gas through a tube furnace preheated to 250 °C. Rapid evaporation of the droplets induced strong capillary forces, causing isotropic compression and thus crumpling of the GO sheets into nearly spherical balls ( Figure 1 b circular inset). In order to increase their conductivity, the crumpled GO particles were further reduced at 600 °C for 2 h in Ar. Their aggregation-resistant property makes crumpled graphene particles dispersible to high concentrations in common organic solvents. [ 13 ] In contrast, r-GO sheets readily aggregate in solution, irreversibly restacking and reducing their available surface area. Following our previous work, MoS x was grown on CC by dip-coating into a solution of ammonium tetrathiomolybdate ((NH 4 ) 2 MoS 4 ; ATM) and annealing at 120 °C for 1 h in a 20:80 H 2 :Ar mix to effectively convert the ATM to MoS x (see Figure 1 a). [ 7 ] The MoS x loading level was varied by adjusting the ATM concentration from 1–100 mg mL −1 . Alternatively, CC substrates were fi rst modifi ed with crumpled-graphene before growth of MoS x , as shown in Figure 1 b. Dried crumpled-graphene powders were redispersed in dimethylformamide (DMF) via ultrasonication to 25 mg mL −1 and a 10 wt% GO dispersion Hydrogen production from water splitting is being explored as a clean way to reduce our reliance on hydrocarbon fuels. [ 1 ]

TL;DR: In this paper, the authors assess the status of knowledge of binary central stars discovered because of irradiation effects and show that the survey technique is biased against binaries with long periods and this fact is used to explain why the periods of all the binaries discovered by this survey are smaller than 3 days.

TL;DR: Simulation suggests that Blu-ray patterns could be broadly applied for solar cells made of other materials, and as a proof-of-concept, imprinting polymer solar cells with the Blu-rays patterns indeed increases their efficiencies.