The high instantaneous luminosity of the CERN Large Hadron Collider leads to multiple proton–proton interactions in the same or nearby bunch crossings (pileup). Advanced pileup mitigation algorithms ...are designed to remove this noise from pileup particles and improve the performance of crucial physics observables. This study implements a semi-supervised graph neural network for particle-level pileup noise removal, by identifying individual particles produced from pileup. The graph neural network is firstly trained on charged particles with known labels, which can be obtained from detector measurements on data or simulation, and then inferred on neutral particles for which such labels are missing. This semi-supervised approach does not depend on the neutral particle pileup label information from simulation, and thus allows us to perform training directly on experimental data. The performance of this approach is found to be consistently better than widely-used domain algorithms and comparable to the fully-supervised training using simulation truth information. The study serves as the first attempt at applying semi-supervised learning techniques to pileup mitigation, and opens up a new direction of fully data-driven machine learning pileup mitigation studies.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Single atoms anchored on stable and robust two-dimensional (2D) materials are attractive catalysts for carbon monoxide (CO) oxidation. Here, 3d (Fe-Zn), 4d (Ru-Cd), and 5d (Os-Hg) transition ...metal-decorated Nb2S2C monolayers were systematically studied as potential single-atom catalysts for low-temperature CO oxidation reactions by performing first-principles calculations. Sulfur vacancies are essential for stabilizing the transition metals anchored on the surface of defective Nb2S2C. After estimating the structure stability, the aggregation trend of the embedded metal atoms, and adsorption strength of reactants and products, Zn-decorated defective Nb2S2C is predicted to be a promising catalyst to facilitate CO oxidation through the Langmuir–Hinshelwood (LH) mechanism with an energy barrier of only 0.25 eV. Our investigation indicates that defective carbosulfides can be promising substrates to generate efficient and low-cost single-atom catalysts for low-temperature CO oxidation.
By performing first-principles calculations, we propose to introduce acetylenyl (−CC−) into the honeycomb kagome lattices of heterotriangulenes (HT)-based two-dimensional (2D) polymers to construct ...2D HT-polyynes with tunable electronic and optical properties for photocatalysis. It is found that the band gap can be effectively reduced to a moderate value of around 2.00 eV by increasing the number of −CC– (n = 1, 2, 3) in the skeletons, contributing to enhanced light-harvesting ability in the visible range of the spectrum. Interestingly, the band edges of 2D HT-polyynes shift upward after incorporating with −CC– and then shift downward when the number of incorporated −CC– increases from 1 to 2 and 3. Possessing moderate band gap and matching band-edge alignments, high carrier mobility, and pronounced light-harvesting capability, the designed 2D HT-polyynes are predicted to be potential candidates for photocatalytic hydrogen production.
It is crucial to comprehensively understand the thermal pyrolysis behavior of lignin and the underlying mechanisms to effectively convert lignin into high-value-added chemical compounds. However, the ...high complexity and heterogeneity of lignin make it challenging to comprehend its pyrolysis behavior by using conventional experimental methods. Here, we report the development of a computational model that integrates stochastic cluster dynamics to simulate lignin pyrolysis under different temperatures and heating rates. The lignin model molecules were created by leveraging experimental data to accurately represent the chemical structure and composition of lignin, which were used to further predict and validate the distribution of products formed during the fast and slow pyrolysis processes, respectively. Fast pyrolysis was found to be particularly favorable for the yield of liquid products leading to extensive depolymerization and fragmentation of the lignin macromolecules. During this process, the short residence time can promote the formation of phenols through the cracking of carboxylic acid and aldehyde and particularly inhibit the coupling reaction of free radicals into dimer compounds. In addition, the constitute bond breaking of functional groups on the benzene rings further promote the transformation between different varieties of high-value phenolic derivatives. Our investigation provides a comprehensive understanding of lignin pyrolysis and shed new lights on the development of effective strategies for biomass degradation.
Background The clinical practice guidelines in general practice can improve healthcare quality in primary health care, however, no study has yet systematically investigated the current status and ...quality of the guidelines in China. Objective To investigate the current status and influencing factors of quality of the guidelines in China. Methods We searched China National Knowledge Infrastructure, Wanfang Data Knowledge Service Platform, Chinese biomedical literature database, and CQVIP website, and included the published guidelines in China. We analyzed the basic characteristics and used RIGHT to evaluate the reporting quality and AGREE-China for methodological quality. Results A total of 150 guidelines were included, mainly published from 2019 to 2021. Most of the guidelines〔108 (72.0%) 〕focused on the diagnosis and treatment of diseases. The top three specialties were cardiovascular disease〔40 (26.7%) 〕, gastroenterology〔31 (20.7%) 〕, and clinical pharmacy〔27 (18.0%) 〕. The main development institutions wer
By performing first-principles calculations, a MoS 2 monolayer with a Co atom doped at the sulfur defect (Co- S MoS 2 ) was investigated as a single-atom catalyst (SAC) for CO oxidation. The Co atom ...is strongly constrained at the S-vacancy site of MoS 2 without forming clusters by showing a high diffusion energy barrier, ensuring good stability to catalyze CO oxidation. The CO and O 2 adsorption behavior on Co- S MoS 2 surface and four reaction pathways, namely, the Eley–Rideal (ER), Langmuir–Hinshelwood (LH), trimolecular Eley–Rideal (TER) as well as the New Eley–Rideal (NER) mechanisms are studied to understand the catalytic activity of Co- S MoS 2 for CO oxidation. The CO oxidation is more likely to proceed through the LH mechanism, and the energy barrier for the rate-limiting step is only 0.19 eV, smaller than that of noble metal-based SACs. Additionally, the NER mechanism is also favorable with a low energy barrier of 0.26 eV, indicating that the Co- S MoS 2 catalyst can effectively promote CO oxidation at low temperatures. Our investigation demonstrates that the S-vacancy of MoS 2 plays an important role in enhancing the stability and catalytic activity of Co atoms and Co- S MoS 2 is predicted to be a promising catalyst for CO oxidation.
Hydrodeoxygenation (HDO) reaction is a pivotal process for upgrading bio-oil to yield value-added chemicals. However, an unclear understanding of the HDO mechanism hinders the development of ...effective catalysts to produce high-value-added aromatics. By employing first-principles calculations and utilizing phenol as a model molecule, we systematically investigate the thermodynamic and kinetic processes of HDO and demonstrate that the initial adsorption configuration of phenol dictates the reaction pathways. We propose dual-atom catalysts (DACs) as promising candidates for selectively converting phenol to benzene. The correlation between dimetal atoms interaction and catalytic performance underscores that the synergistic effect between the dimetal atoms on the C2N monolayer is essential in modulating the binding strength of adsorbed species and determining the catalytic activity. The direct deoxygenation pathway is identified as the optimal process for most DACs, and MoMo-C2N is screened to be a promising HDO catalyst with low energy barrier and a high turnover frequency.
Designing electrocatalysts with good electrical conductivity, low cost, and abundant surface active sites to actively and selectively catalyze the CO 2 reduction reaction (CRR) is crucial for ...mitigating the impact of high carbon emissions. By performing first principles calculations, the potential of Mo 3 (C 6 O 6 ) 2 monolayers as CRR electrocatalysts was explored by systematically examining the thermodynamic processes of all possible elementary steps. The Mo centers turn out to be the active sites that can selectively promote CRR and produce methane as the main product. The limiting potential for the potential-determining step (PDS) of the first reaction cycle is −0.58 V, less negative than that of the widely studied Cu(211) surface (−0.74 V). For subsequent reaction cycles, the Mo sites tend to coordinate with hydroxyl, which can further promote the CRR and lower the thermodynamic barrier of the PDS to 0.39 eV and suppress the side reaction of hydrogen evolution. With good conductivity and high catalytic activity and selectivity, the hydroxyl terminated Mo 3 (C 6 O 6 ) 2 monolayer is predicted to be an effective electrocatalyst for CRR.
Designing electrocatalysts with good electrical conductivity, low cost, and abundant surface active sites to actively and selectively catalyze the CO
2
reduction reaction (CRR) is crucial for ...mitigating the impact of high carbon emissions. By performing first principles calculations, the potential of Mo
3
(C
6
O
6
)
2
monolayers as CRR electrocatalysts was explored by systematically examining the thermodynamic processes of all possible elementary steps. The Mo centers turn out to be the active sites that can selectively promote CRR and produce methane as the main product. The limiting potential for the potential-determining step (PDS) of the first reaction cycle is −0.58 V, less negative than that of the widely studied Cu(211) surface (−0.74 V). For subsequent reaction cycles, the Mo sites tend to coordinate with hydroxyl, which can further promote the CRR and lower the thermodynamic barrier of the PDS to 0.39 eV and suppress the side reaction of hydrogen evolution. With good conductivity and high catalytic activity and selectivity, the hydroxyl terminated Mo
3
(C
6
O
6
)
2
monolayer is predicted to be an effective electrocatalyst for CRR.
Mo
3
(C
6
O
6
)
2
monolayers are potential electrocatalysts for CO
2
reduction reaction (CRR). The electrochemical performances can be further improved by coordinating with hydroxyl groups, which show improved performance for the production of methane.
