352 research outputs found
CDSD: Chinese Dysarthria Speech Database
We present the Chinese Dysarthria Speech Database (CDSD) as a valuable
resource for dysarthria research. This database comprises speech data from 24
participants with dysarthria. Among these participants, one recorded an
additional 10 hours of speech data, while each recorded one hour, resulting in
34 hours of speech material. To accommodate participants with varying cognitive
levels, our text pool primarily consists of content from the AISHELL-1 dataset
and speeches by primary and secondary school students. When participants read
these texts, they must use a mobile device or the ZOOM F8n multi-track field
recorder to record their speeches. In this paper, we elucidate the data
collection and annotation processes and present an approach for establishing a
baseline for dysarthric speech recognition. Furthermore, we conducted a
speaker-dependent dysarthric speech recognition experiment using an additional
10 hours of speech data from one of our participants. Our research findings
indicate that, through extensive data-driven model training, fine-tuning
limited quantities of specific individual data yields commendable results in
speaker-dependent dysarthric speech recognition. However, we observe
significant variations in recognition results among different dysarthric
speakers. These insights provide valuable reference points for
speaker-dependent dysarthric speech recognition.Comment: 9 pages, 3 figure
The Origin of Catalytic Benzylic CâH Oxidation over a RedoxâActive MetalâOrganic Framework
From Wiley via Jisc Publications RouterHistory: received 2021-02-15, rev-recd 2021-03-27, pub-electronic 2021-06-04Article version: VoRPublication status: PublishedFunder: Engineering and Physical Sciences Research Council; Id: http://dx.doi.org/10.13039/501100000266; Grant(s): EP/I011870Funder: H2020 European Research Council; Id: http://dx.doi.org/10.13039/100010663; Grant(s): 742401Abstract: Selective oxidation of benzylic CâH compounds to ketones is important for the production of a wide range of fine chemicals, and is often achieved using toxic or precious metal catalysts. Herein, we report the efficient oxidation of benzylic CâH groups in a broad range of substrates under mild conditions over a robust metalâorganic framework material, MFMâ170, incorporating redoxâactive [Cu2II(O2CR)4] paddlewheel nodes. A comprehensive investigation employing electron paramagnetic resonance (EPR) spectroscopy and synchrotron Xâray diffraction has identified the critical role of the paddlewheel moiety in activating the oxidant tBuOOH (tertâbutyl hydroperoxide) via partial reduction to [CuIICuI(O2CR)4] species
Efficient photocatalytic reduction of CO2 catalyzed by the metalâorganic framework MFM-300(Ga)
Photocatalytic reduction of CO2 to carbon fuels is an important target but highly challenging to achieve. Here, we report the efficient photoconversion of CO2 into formic acid over a Ga(III)-based metalâorganic framework (MOF) material using triethanolamine as the sacrificial agent. Under light irradiation and at room temperature, photoreduction of CO2 over MFM-300(Ga) yields formic acid with a selectivity of 100%, a high productivity of 502 ± 18 ÎŒmol·gcatâ1·hâ1, and excellent catalytic stability. In situ electron paramagnetic resonance spectroscopy reveals that MFM-300(Ga) promotes the generation of CO2âąâ radical anions as a reaction intermediate driven by strong binding and activation of CO2 molecules at the bridging âOH sites within the pore. This study represents the first example of a Ga(III)-based MOF catalyst for CO2 reduction
Evolution of bismuth-based metal?organic frameworks for efficient electroreduction of CO2
Understanding the structural and chemical changes that reactive metalâorganic frameworks (MOFs) undergo is crucial for the development of new efficient catalysts for electrochemical reduction of CO2. Here, we describe three Bi(III) materials, MFM-220, MFM-221 and MFM-222, which are constructed from the same ligand (biphenyl-3,3âČ,5,5âČ-tetracarboxylic acid) but which show distinct porosity with solvent-accessible voids of 49.6%, 33.6% and 0%, respectively. We report the first study of the impact of porosity of MOFs on their evolution as electrocatalysts. A Faradaic efficiency of 90.4% at â1.1 V vs. RHE (reversible hydrogen electrode) is observed for formate production over an electrode decorated with MFM-220-p, formed from MFM-220 on application of an external potential in the presence of 0.1 M KHCO3 electrolyte. In situ electron paramagnetic resonance spectroscopy confirms the presence of ·COOH radicals as a reaction intermediate, with an observed stable and consistent Faradaic efficiency and current density for production of formate by electrolysis over 5 h. This study emphasises the significant role of porosity of MOFs as they react and evolve during electroreduction of CO2 to generate value-added chemicals
Multidifferential study of identified charged hadron distributions in -tagged jets in proton-proton collisions at 13 TeV
Jet fragmentation functions are measured for the first time in proton-proton
collisions for charged pions, kaons, and protons within jets recoiling against
a boson. The charged-hadron distributions are studied longitudinally and
transversely to the jet direction for jets with transverse momentum 20 GeV and in the pseudorapidity range . The
data sample was collected with the LHCb experiment at a center-of-mass energy
of 13 TeV, corresponding to an integrated luminosity of 1.64 fb. Triple
differential distributions as a function of the hadron longitudinal momentum
fraction, hadron transverse momentum, and jet transverse momentum are also
measured for the first time. This helps constrain transverse-momentum-dependent
fragmentation functions. Differences in the shapes and magnitudes of the
measured distributions for the different hadron species provide insights into
the hadronization process for jets predominantly initiated by light quarks.Comment: All figures and tables, along with machine-readable versions and any
supplementary material and additional information, are available at
https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2022-013.html (LHCb
public pages
Study of the decay
The decay is studied
in proton-proton collisions at a center-of-mass energy of TeV
using data corresponding to an integrated luminosity of 5
collected by the LHCb experiment. In the system, the
state observed at the BaBar and Belle experiments is
resolved into two narrower states, and ,
whose masses and widths are measured to be where the first uncertainties are statistical and the second
systematic. The results are consistent with a previous LHCb measurement using a
prompt sample. Evidence of a new
state is found with a local significance of , whose mass and width
are measured to be and , respectively. In addition, evidence of a new decay mode
is found with a significance of
. The relative branching fraction of with respect to the
decay is measured to be , where the first
uncertainty is statistical, the second systematic and the third originates from
the branching fractions of charm hadron decays.Comment: All figures and tables, along with any supplementary material and
additional information, are available at
https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2022-028.html (LHCb
public pages
Measurement of the ratios of branching fractions and
The ratios of branching fractions
and are measured, assuming isospin symmetry, using a
sample of proton-proton collision data corresponding to 3.0 fb of
integrated luminosity recorded by the LHCb experiment during 2011 and 2012. The
tau lepton is identified in the decay mode
. The measured values are
and
, where the first uncertainty is
statistical and the second is systematic. The correlation between these
measurements is . Results are consistent with the current average
of these quantities and are at a combined 1.9 standard deviations from the
predictions based on lepton flavor universality in the Standard Model.Comment: All figures and tables, along with any supplementary material and
additional information, are available at
https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2022-039.html (LHCb
public pages
Two-dimensional materials: synthesis and applications in the electro-reduction of carbon dioxide
The emission of CO2 has become an increasingly prominent issue. Electrochemical reduction of CO2 to value-added chemicals provides a promising strategy to mitigate energy shortage and achieve carbon neutrality. Two-dimensional (2D) materials are highly attractive for the fabrication of catalysts owing to their special electronic and geometric properties as well as a multitude of edge active sites. Various 2D materials have been proposed for synthesis and use in the conversion of CO2 to versatile carbonous products. This review presents the latest progress on various 2D materials with a focus on their synthesis and applications in the electrochemical reduction of CO2. Initially, the advantages of 2D materials for CO2 electro-reduction are briefly discussed. Subsequently, common methods for the synthesis of 2D materials and the role of these materials in the electrochemical reduction of CO2 are elaborated. Finally, some perspectives for future investigations of 2D materials for CO2 electro-reduction are proposed
Customization of functional MOFs by a modular design strategy for target applications
Herein, we propose a versatile âfunctional modular assemblyâ strategy for customizing MOFs that allows installing the desired functional unit into a host material. The functional unit could be switched according to different applications. MOF-808, a highly stable Zr-MOF containing dangling formate groups, was selected as a host material for demonstration. Functional molecules with carboxyl connectors can be directly inserted into MOF-808 to form functional modular MOFs (FM-MOFs) through single substitution, while for those without carboxyl connectors, a pre-designed convertor was grafted firstly followed by the functional molecules in a stepwise manner. A series of tailor-made FM-MOFs were generated and show excellent performance toward different applications, such as adsorption, catalysis, fluorescent sensing, electrochemistry, and the control of surface wettability. On the other hand, the functional units on the FM-MOFs can switch freely and completely via full interconversion, as well as partly to construct multivariate MOFs (MTV-MOFs). Therefore, this strategy provides a benchmark for rapid customization of functional MOFs for diverse applications that can realize the rapid modular design of materials
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