Investigations on MoS_(2)plasma by infra-red pulsed laser irradiation in high vacuum

MoS_(2)targets were irradiated by infra-red(IR)pulsed laser in a high vacuum to determine hot plasma parameters,atomic,molecular and ion emission,and angular and charge state distributions.In this way,pulsed laser deposition(PLD)of thin films on graphene oxide substrates was also realized.An Nd:YAG laser,operating at the 1064 nm wavelength with a 5 ns pulse duration and up to a 1 J pulse energy,in a single pulse or at a 10 Hz repetition rate,was employed.Ablation yield was measured as a function of the laser fluence.Plasma was characterized using different analysis techniques,such as time-of-flight measurements,quadrupole mass spectrometry and fast CCD visible imaging.The so-produced films were characterized by composition,thickness,roughness,wetting ability,and morphology.When compared to the MoS_(2)targets,they show a slight decrease of S with respect to Mo,due to higher ablation yield,low fusion temperature and high sublimation in vacuum.The pulsed IR laser deposited Mo Sx(with 1<x<2)films are uniform,with a thickness of about 130 nm,a roughness of about 50 nm and a higher wettability than the MoS_(2)targets.Some potential applications of the pulsed IR laser-deposited Mo Sx films are also presented and discussed.

Bitcoin:a new proof‑of‑work system with reduced variance

Since its inception,bitcoin has used the popular consensus protocol proof-of-work(PoW).PoW has a well-known flaw:it distributes all rewards to a single miner(or pool)who inserts a new block.Consequently,the variance of rewards and the mining enter-prise risk are extremely high.In 2016,Shi proposed addressing this problem with a theoretical algorithm.We introduce an easily-implemented PoW variant that improves Shi’s idea.The network must not find a single nonce but a few to insert a block.This simple change allows for a fairer distribution of rewards and also has the effect of regularizing the insertion time of blocks.This method would facilitate the emergence of small pools or autonomous miners.

An Adaptive hp-DG-FE Method for Elliptic Problems: Convergence and Optimality in the 1D Case

We propose and analyze an hp-adaptive DG-FEM algorithm, termed hp-ADFEM, and its one-dimensional realization, which is convergent, instance optimal, and h- and p-robust. The procedure consists of iterating two routines:one hinges on Binev's algorithm for the adaptive hp-approximation of a given function, and finds a near-best hp-approximation of the current discrete solution and data to a desired accuracy;the other one improves the discrete solution to a finer but comparable accuracy, by iteratively applying D?rfler marking and h refinement.

Strongly enhanced light trapping in a two-dimensional silicon nanowire random fractal array

We report on the unconventional optical properties exhibited by a two-dimensional array of thin Si nanowires arranged in a random fractal geometry and fabricated using an inexpensive,fast and maskless process compatible with Si technology.The structure allows for a high light-trapping efficiency across the entire visible range,attaining total reflectance values as low as 0.1%when the wavelength in the medium matches the length scale of maximum heterogeneity in the system.We show that the random fractal structure of our nanowire array is responsible for a strong in-plane multiple scattering,which is related to the material refractive index fluctuations and leads to a greatly enhanced Raman scattering and a bright photoluminescence.These strong emissions are correlated on all length scales according to the refractive index fluctuations.The relevance and the perspectives of the reported results are discussed as promising for Si-based photovoltaic and photonic applications.

Remarks on Some Compact Symplectic Solvmanifolds

We study the hard Lefschetz property on compact symplectic solvmanifolds,i.e.,compact quotients M=ΓG of a simply-connected solvable Lie group G by a latticeΓ,admitting a symplectic structure.

PEG-PLGA electrospun nanofibrous membranes loaded with Au@Fe2O3 nanoparticles for drug delivery applications

A PEGylated-PLGA random nanofibrous membrane loaded with gold and iron oxide nanoparticles and with silibinin was prepared by electrospinning deposition. The nanofibrous membrane can be remotely controlled and activated by a laser light or magnetic field to release biological agents on demand. The nanosystems were characterized using scanning electron microscopy, Fourier transform infrared spectroscopy, nuclear magnetic resonance spectroscopy, and thermogravimetric analyses. The drug loading efficiency and drug content percentages were determined by UV-vis optical absorption spectroscopy. The nanofibrous membrane irradiated by a relatively low-intensity laser or stimulated by a magnetic field showed sustained silibinin release for at least 60 h, without the burst effect. The proposed low-cost electrospinning procedure is capable of assembling, via a one-step procedure, a stimuli-responsive drug-loaded nanosystem with metallic nanoparticles to be externally activated for controlled drug delivery.

A study of the hydrogen bonds effect on the water density and the liquid-liquid transition

We study the hydrogen bonds effect on the water density as a function of temperature and pressure from the supercritical region to the metastable supercooled and amorphous phases. We identify two important thermodynamic thresholds, that is P~*■2 kbar and T~*■315 K, that separate two different water behaviors in terms of hydrogen bonding capability. For T < T~* and P < P~* the formation and stability of hydrogen bonded local structures are enhanced. The additional analyses of the proton NMR chemical shift and of the relaxation time confirm this evidence and highlight the structure breaking effects of the pressure. The investigation of both structural and dynamical quantities allow us to draw a complete picture of the water properties in terms of the temperaturepressure dependence of hydrogen bonding.

Hidden Vacuum Rabi Oscillations:Dynamical Quantum Superpositions of On/Off Interaction between a Single Quantum Dot and a Microcavity

We show that it is possible to realize quantum superpositions of switched-on and-off strong light-matter interaction in a single quantum dot-semiconductor microcavity system.Such superpositions enable the observation of counterintuitive quantum conditional dynamics effects.Situations are possible where cavity photons as well as the emitter luminescence display exponential decay but their joint detection probability exhibits vacuum Rabi oscillations.Remarkably,these quantum correlations are also present in the nonequilibrium steady state spectra of such coherently driven dissipative quantum systems.

On Some Numerical Semigroup Transforms

In this paper we introduce a particular semigroup transform A that fixes the invariants involved in Wilf's conjecture,except the embedding dimension.It also allows one to arrange the set of non-ordinary and non-irreducible numerical semigroups in a family of rooted trees.In addition,we study another transform,having similar features,that has been introduced by Bras-Amorós,and we make a comparison of them.In particular,we study the behavior of the embedding dimension under the action of such transforms,providing some consequences concerning Wilf's conjecture.

The Jacobian Dual of Certain Mixed Product Ideals

We consider the symmetric algebra of a class of monomial ideals generated by s-sequences.For these ideals with linear syzygies,we determine their Jacobian dual modules and study their duality properties.