1,685 research outputs found
The influence of oceanographic processes on contourite features:A multidisciplinary study of the northern South China Sea
Towards Prediction of Financial Crashes with a D-Wave Quantum Computer
Prediction of financial crashes in a complex financial network is known to be
an NP-hard problem, i.e., a problem which cannot be solved efficiently with a
classical computer. We experimentally explore a novel approach to this problem
by using a D-Wave quantum computer to obtain financial equilibrium more
efficiently. To be specific, the equilibrium condition of a nonlinear financial
model is embedded into a higher-order unconstrained binary optimization (HUBO)
problem, which is then transformed to a spin- Hamiltonian with at most
two-qubit interactions. The problem is thus equivalent to finding the ground
state of an interacting spin Hamiltonian, which can be approximated with a
quantum annealer. Our experiment paves the way to study quantitative
macroeconomics, enlarging the number of problems that can be handled by current
quantum computers
Biomass derived oligosaccharides for potential leather tanning
The global demand for renewable and affordable feedstocks, combined with the worldwide targets for reducing carbon emissions, is the driving force behind a breakthrough in resource revolution and GreenTech innovations..
Novel biomass-based polymeric dyes: preparation and performance assessment in the dyeing of biomass-derived aldehyde-tanned leather
High-performance chrome-free leather production is currently one of the most concerning needs to warrant the sustainable development of the leather industry due to the serious chrome pollution. Driven by these research challenges, this work explores using biobased polymeric dyes (BPDs) based on dialdehyde starch and reactive small-molecule dye (reactive red 180, RD-180) as novel dyeing agents for leather tanned using a chrome-free, biomass-derived aldehyde tanning agent (BAT). FTIR, 1H NMR, XPS, and UV-visible spectrometry analyses indicated that a Schiff base structure was generated between the aldehyde group of dialdehyde starch (DST) and the amino group of RD-180, resulting in the successful load of RD-180 on DST to produce BPD. The BPD could first penetrate the BAT-tanned leather efficiently and then be deposited on the leather matrix, thus exhibiting a high uptake ratio. Compared with the crust leathers prepared using a conventional anionic dye (CAD), dyeing, and RD-180 dyeing, the BPD-dyed crust leather not only had better coloring uniformity and fastness but it also showed a higher tensile strength, elongation at break, and fullness. These data suggest that BPD has the potential to be used as a novel sustainable polymeric dye for the high-performance dyeing of organically tanned chrome-free leather, which is paramount to ensuring and promoting the sustainable development of the leather industry
C–H activation and metalation at electrode surfaces: 2,3-dimethyl-1,4-dihydroxybenzene on Pd(pc) and Pd(111) studied by TLE, HREELS and DFT
Previous studies, based on thin-layer electrochemistry (TLE), in situ scanning tunneling microscopy (EC-STM), high-resolution electron energy loss spectroscopy (HREELS) and density functional theory (DFT) computations, on the chemical adsorption of hydroquinone from aqueous solutions onto atomically smooth Pd (and Pt) electrode surfaces indicated two modes of attachment that depended upon the solution concentration. At low activities, the diphenol was oxidatively chemisorbed as benzoquinone in a flat orientation, suggestive of a Pd(2,3,5,6-η-C_6H_4O_2) surface complex; at higher concentrations, vertical chemisorption was effected via two C–H bond activations (or metalations) at the 2 and 3 ring positions, evocative of an o-phenylene organopalladium compound. We have extended the work to 2,3-dimethyl-1,4-dihydroxybenzene on Pd(pc) and Pd(111) electrodes to probe the effect of two methyl substituents on only one side of the diphenol ring. Surface coverage and adsorbed-molecule cross section data from TLE and HREELS measurements revealed non-random concentration-dependent adsorbate orientations similar to the oxidative chemisorption of hydroquinone: flat at low concentrations and edgewise at elevated concentrations. The DFT results suggested that, for the flat structure, surface coordination is via the two double bonds of the quinone ring as in [Pd(2,3,5,6-η)-2,3-dimethyl-p-quinone]. For the edge-vertical orientation, a structure analogous to an o-phenylene compound is generated in which C–H bonds at the 5 and 6 ring positions are activated and then metalated. DFT-simulated HREELS spectra helped identify the observed peaks that distinguish the surface-coordinated quinone from the surface-metalated diphenol
A Hierarchical Meta-model for Multi-Class Mental Task Based Brain-Computer Interfaces
In the last few years, many research works have been suggested on Brain-
Computer Interface (BCI), which assists severely physically disabled persons to communicate directly with the help of electroencephalogram (EEG) signal,
generated by the thought process of the brain. Thought generation inside the
brain is a dynamic process, and plenty thoughts occur within a small time
window. Thus, there is a need for a BCI device that can distinguish these
various ideas simultaneously. In this research work, our previous binary-class
mental task classication has been extended to the multi-class mental task problem. The present work proposed a novel feature construction scheme for multi mental task classication. In the proposed method, features ar
Modelling two Energetic Storm Particle Events Observed by Solar Orbiter Using the Combined EUHFORIA and iPATH Models
By coupling the EUropean Heliospheric FORcasting Information Asset (EUHFORIA)
and the improved Particle Acceleration and Transport in the Heliosphere (iPATH)
model, two energetic storm particle (ESP) events, originating from the same
active region (AR 13088) and observed by Solar Orbiter (SolO) on August 31 2022
and September 05 2022, are modelled. While both events originated from the same
active region, they exhibited notable differences, including: 1) the August ESP
event lasted for 7 hours, while the September event persisted for 16 hours; 2)
The time intensity profiles for the September event showed a clear cross-over
upstream of the shock where the intensity of higher energy protons exceeds
those of lower energy protons, leading to positive (``reverse'') spectral
indices prior to the shock passage. For both events, our simulations replicate
the observed duration of the shock sheath, depending on the deceleration
history of the CME. Imposing different choices of escaping length scale, which
is related to the decay of upstream turbulence, the modelled time intensity
profiles prior to the shock arrival also agree with observations. In
particular, the cross-over of this time profile in the September event is well
reproduced. We show that a ``reverse'' upstream spectrum is the result of the
interplay between two length scales. One characterizes the decay of upstream
shock accelerated particles, which are controlled by the energy-dependent
diffusion coefficient, and the other characterizes the decay of upstream
turbulence power, which is related to the process of how streaming protons
upstream of the shock excite Alfv\'{e}n waves. Simulations taking into account
real-time background solar wind, the dynamics of the CME propagation, and
upstream turbulence at the shock front are necessary to thoroughly understand
the ESP phase of large SEP events.Comment: Accepted by A&A. 16 pages, 11 figure
The quantitative proteomes of human-induced pluripotent stem cells and embryonic stem cells
An in-depth proteomic comparison of human-induced pluripotent stem cells, and their parent fibroblast cells, with embryonic stem cells shows that the reprogramming process comprehensively remodels protein expression levels, creating cells that closely resemble natural stem cells
Contourite processes associated with the overflow of Pacific Deep Water within the Luzon Trough: Conceptual and regional implications
Overflows through oceanic gateways govern the exchange of water masses in the world's ocean basins. These exchanges also involve energy, salinity, nutrients, and carbon. As such, the physical features that control overflow can exert a strong influence on regional and global climate. Here, we present the first description of sedimentary processes generated by the overflow of Pacific Deep Water (OPDW). This mass flows southward at approximately 2000–3450 m water depth within the Luzon Trough (gateway) from the Pacific Ocean into the South China Sea. OPDW can be divided into: a) a lower, denser layer (including an associated weak counter-current), which has generated a large contourite depositional system (CDS-1) that includes large erosional (channel and moat), depositional (mounded and plastered drift), and mixed (terrace) contourite features along the trough bottom and walls, and b) an upper mixing layer, which has not generated any significant depositional or erosional contourite features. Where OPDW does not reach the seafloor, it is underlain by bottom water that circulates more sluggishly but has generated a second contourite depositional system (CDS-2) made of a large sheet-like drift. The OPDW flow has generally enhanced since the middle to late Miocene, except in the shallower northernmost corridor. In the deeper main trough, reductions in width and depth of the gateway by Taiwan orogenic events have likely accelerated the overflow. The latest significant enhancening may promote widespread development of contourite depositional systems along the South China Sea's lower continental slope and adjacent deeper areas. This work highlights the importance of gateway-confined overflows in controlling the morphology and sedimentary evolution of adjacent deep marine sedimentary systems. A clear understanding of overflow processes and their products is essential for decoding tectonic control in oceanographic or paleoceanographic processes
3D plasmonic chiral colloids
3D plasmonic chiral colloids are synthesized through deterministically grouping of two gold nanorod AuNRs on DNA origami. These nanorod crosses exhibit strong circular dichroism (CD) at optical frequencies which can be engineered through position tuning of the rods on the origami. Our experimental results agree qualitatively well with theoretical predictions. © 2014 The Royal Society of Chemistry.Peer Reviewe
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