15,392 research outputs found
Synthesis of a ditopic homooxacalix[3]arene for fluorescence enhanced detection of heavy and transition metal ions
A pyrene-appended ratiometric fluorescent chemosensor L based on a synthetic approach of insulating the fluorophore from the ionophore by a specific molecular spacer has been synthesised and characterised. The fluorescence spectra changes of L suggested that the chemosensor can detect heavy and transition metal (HTM) ions ratiometrically and with variable sensitivity according to the substituents present. Ā¹H NMR titration experiments indicated that the three triazole ligands prefer binding with HgĀ²āŗ, PbĀ²āŗ and ZnĀ²āŗ, resulting in a conformational change that produces monomer emission of the pyrene accompanied by the excimer quenching. However, the addition of FeĀ³āŗ, which may be accommodated by the cavity of L, makes the pyrene units move closer to each other, and a discernible increase in the emission intensity of the static excimer is observed. Therefore, it is believed that the ditopic scaffold of the calix[3]arene as a specific molecular spacer here plays an important role in the blocking of the heavy atom effect of HTM ions by insulating the fluorophore from the ionophore given the long distance between the metal cation and the pyrene moiety
The semileptonic and radiative decays within the light-cone sum rules
The measured branching ratio of the meson semileptonic decay , which is based on the CLEO data taken at the
peak of resonance, disagrees with the traditional SVZ sum rules
analysis by about three times. In the paper, we show that this discrepancy can
be eliminated by applying the QCD light-cone sum rules (LCSR) approach to
calculate the transition form factors and .
After extrapolating the LCSR predictions of these TFFs to whole -region,
we obtain . Using the CKM matrix
element and the lifetime from the Particle Data Group, we obtain
and , which agree with the CLEO measurements within errors. We
also calculate the branching ratios of the two meson radiative processes
and obtain and , which also agree with the Belle measurements within errors. Thus we
think the LCSR approach is applicable for dealing with the meson decays.Comment: 12 pages, 7 figures, version to be published in EPJ
A pyrene-armed hexahomotrioxacalix[3]arene as a multi-sensor via synergistic and demetallation effects
A new pyrene-armed hexahomotrioxacalix[3]arene L has been synthesized, which exhibits a pronounced fluorescence enhancement response toward CuĀ²āŗ ions via a ZnĀ²āŗ or CdĀ²āŗ triggered synergistic effect. Additionally, the LĀ·CuĀ²āŗ+ complex can subsequently serve as a sensor for Fā» via anion-induced demetallation. The fluorescence responses by the input of CuĀ²āŗ, ZnĀ²āŗ/CdĀ²āŗ and Fā» can be constructed as a combinational logic gate which mimics a set of molecular traffic signals
Systematic study of proton radioactivity of spherical proton emitters within various versions of proximity potential formalisms
In this work we present a systematic study of the proton radioactivity
half-lives of spherical proton emitters within the Coulomb and proximity
potential model. We investigate 28 different versions of the proximity
potential formalisms developed for the description of proton radioactivity,
decay and heavy particle radioactivity. It is found that 21
of them are not suitable to deal with the proton radioactivity, because the
classical turning points cannot be obtained due to the fact
that the depth of the total interaction potential between the emitted proton
and the daughter nucleus is above the proton radioactivity energy. Among the
other 7 versions of the proximity potential formalisms, it is Guo2013 which
gives the lowest rms deviation in the description of the experimental
half-lives of the known spherical proton emitters. We use this proximity
potential formalism to predict the proton radioactivity half-lives of 13
spherical proton emitters, whose proton radioactivity is energetically allowed
or observed but not yet quantified, within a factor of 3.71.Comment: 10 pages, 5 figures. This paper has been accepted by The European
Physical Journal A (in press 2019
Review of existing peer-to-peer energy trading projects
Peer-to-Peer (P2P) energy trading is a novel paradigm of power system operation, where people can generate their own energy from Renewable Energy Sources (RESs) in dwellings, offices and factories, and share it with each other locally. The number of projects and trails in this area has significantly increased recently all around the world. This paper elaborates main focuses and outcomes of those projects, and compares their similarities and differences. The results show that although many of the trails focus on the business models acting similarly to a supplier's role in the electricity sector, it is also necessary to design the necessary communication and control networks that could enable P2P energy trading in or among local Microgrids
Synthesis and evaluation of a novel fluorescent sensor based on hexahomotrioxacalix[3]arene for ZnĀ²+ and CdĀ²+
A novel type of selective and sensitive fluorescent sensor having triazole rings as the binding sites on the lower rim of a hexahomotrioxacalix[3]arene scaffold in a cone conformation is reported. This sensor has desirable properties for practical applications, including selectivity for detecting ZnĀ²āŗ and CdĀ²āŗ in the presence of excess competing metal ions at low ion concentration or as a fluorescence enhancement type chemosensor due to the cavity of calixarene changing from a āflattened-coneā to a more-upright form and inhibition of PET. In contrast, the results suggested that receptor 1 is highly sensitive and selective for CuĀ²āŗ and FeĀ³āŗ as a fluorescence quenching type chemosensor due to the photoinduced electron transfer (PET) or heavy atom effect
A bidding system for peer-to-peer energy trading in a grid-connected microgrid
Peer-to-Peer (P2P) energy trading is a novel paradigm of power system operation, where people can generate their own energy from Renewable Energy Sources (RESs) in dwellings, offices and factories, and share it with each other locally. An architecture model was proposed to present the design and interoperability aspects of components for P2P energy trading in a microgrid. A specific Customer-to-Customer business model was introduced in a benchmark grid-connected microgrid based on the architecture model. The core component of a bidding system, called Elecbay, was also proposed and simulated using game theory. Test results show that P2P energy trading is able to balance local generation and demand, therefore, has a potential to enable a large penetration of RESs in the power grid
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