Electron and phonon properties and gas storage in carbon honeycomb

A new kind of three-dimensional carbon allotropes, termed carbon honeycomb (CHC), has recently been synthesized [PRL 116, 055501 (2016)]. Based on the experimental results, a family of graphene networks are constructed, and their electronic and phonon properties are calculated by using first principles methods. All networks are porous metal with two types of electron transport channels along the honeycomb axis and they are isolated from each other: one type of channels is originated from the orbital interactions of the carbon zigzag chains and is topologically protected, while the other type of channels is from the straight lines of the carbon atoms that link the zigzag chains and is topologically trivial. The velocity of the electrons can reach ~10^6 m/s. Phonon transport in these allotropes is strongly anisotropic, and the thermal conductivities can be very low when compared with graphite by at least a factor of 15. Our calculations further indicate that these porous carbon networks possess high storage capacity for gaseous atoms and molecules in agreement with experiment.Comment: Nanoscale, 201

Double Kagome bands in a two-dimensional phosphorus carbide P2C3

The interesting properties of Kagome bands, consisting of Dirac bands and a flat band, have attracted extensive attention. However, the materials with only one Kagome band around the Fermi level cannot possess physical properties of Dirac fermions and strong correlated fermions simultaneously. Here, we propose a new type of band structure --- double Kagome bands, which can realize coexistence of the two kinds of fermions. Moreover, the new band structure is found to exist in a new two-dimensional material, phosphorus carbide P2C3. The carbide material shows good stability and unusual electronic properties. Strong magnetism appears in the structure by hole doping of the flat band, which results in spin splitting of the Dirac bands. The edge states induced by Dirac and flat bands coexist on the Fermi level, indicating outstanding transport characteristics. In addition, a possible route to experimentally grow P2C3 on some suitable substrates such as the Ag (111) surface is also discussed

The VEP Booster: A Closed-Loop AI System for Visual EEG Biomarker Auto-generation

Effective visual brain-machine interfaces (BMI) is based on reliable and stable EEG biomarkers. However, traditional adaptive filter-based approaches may suffer from individual variations in EEG signals, while deep neural network-based approaches may be hindered by the non-stationarity of EEG signals caused by biomarker attenuation and background oscillations. To address these challenges, we propose the Visual Evoked Potential Booster (VEP Booster), a novel closed-loop AI framework that generates reliable and stable EEG biomarkers under visual stimulation protocols. Our system leverages an image generator to refine stimulus images based on real-time feedback from human EEG signals, generating visual stimuli tailored to the preferences of primary visual cortex (V1) neurons and enabling effective targeting of neurons most responsive to stimuli. We validated our approach by implementing a system and employing steady-state visual evoked potential (SSVEP) visual protocols in five human subjects. Our results show significant enhancements in the reliability and utility of EEG biomarkers for all individuals, with the largest improvement in SSVEP response being 105%, the smallest being 28%, and the average increase being 76.5%. These promising results have implications for both clinical and technological applicationsComment: 19 pages, 6 figure

Three-dimensional Pentagon Carbon with a genesis of emergent fermions

Carbon, the basic building block of our universe, enjoys a vast number of allotropic structures. Owing to its bonding characteristic, most carbon allotropes possess the motif of hexagonal rings. Here, with first-principles calculations, we discover a new metastable three-dimensional carbon allotrope entirely composed of pentagon rings. The unique structure of this "Pentagon Carbon" leads to extraordinary electronic properties, making it a cornucopia of emergent topological fermions. Under lattice strain, Pentagon Carbon exhibits topological phase transitions, generating a series of novel quasiparticles, from isospin-1 triplet fermions, to triply-degenerate fermions, and further to concatenated Weyl-loop fermions. Its Landau level spectrum also exhibits distinct features, including a huge number of almost degenerate chiral Landau bands, implying pronounced magneto-transport signals. Our work not only discovers a remarkable carbon allotrope with highly rare structural motifs, it also reveals a fascinating hierarchical particle genesis with novel topological fermions beyond the Dirac and Weyl paradigm

Highly discriminative and adaptive feature extraction method based on NMF-MFCC for event recognition of Φ-OTDR

To enhance the capability of phase-sensitive optical time domain reflectometers (Φ-OTDR) to recognize disturbance events, an improved adaptive feature extraction method based on NMF-MFCC is proposed, which replaces the fixed filter bank used in the traditional method to extract the mel-frequency cepstral coefficient (MFCC) features by a spectral structure obtained from the Φ-OTDR signal spectrum using nonnegative matrix factorization (NMF). Three typical events on fences are set as recognition targets in our experiments, and the results show that the NMF-MFCC features have higher distinguishability, with the corresponding recognition accuracy reaching 98.47%, which is 7% higher than that using the traditional MFCC features.</p

Sidelobe Suppression Method with Improved CLEAN Algorithm for Pulse Compression OTDR

Although pulse compression optical time domain reflectometry (PC-OTDR) exhibits high performance in spatial resolution and dynamic range, it inevitably introduces auto-correlation sidelobes, potentially impacting measurement accuracy. In this letter, an improved CLEAN algorithm is proposed to efficiently suppress sidelobes and enhance the peak-to-sidelobe ratio (PSLR) of signals in PC-OTDR. The proposed method introduces an adaptive step factor instead of the traditional fixed factor to reduce the number of iterations. Compared to the traditional method, the proposed method achieves a 2.87 dB improvement of PSLR from a 10 km sensing fiber. In addition, the computation time cost is significantly reduced, which is 1.92 s less than that of the traditional CLEAN algorithm

Pharmacokinetics and pharmacodynamics of insulin lispro 25 versus the original preparation (Humalog®25) in Chinese healthy male volunteers

Background: There are approximately 537 million adults with diabetes worldwide, and insulin still plays an important role in its treatment. However, the long-term use of insulin imposes a significant financial burden on patients. This study aims to explore the pharmacokinetic (PK)/ pharmacodynamic (PD) parameters of generic premixed insulin lispro 25 (25% insulin lispro and 75% protamine zinc lispro) and evaluate the bio-equivalence between generic and brand-name preparations to reduce medical costs while ensuring the effectiveness and safety of treatment.Research design and method: This is a single-center, randomized, open-label, two-period, crossover study. This study recruited 52 healthy volunteers and randomly divided them into two sequences to receive either the test (T) preparation or the reference (R) preparation in each period (Chinese Drug Trial Identifier: CTR20202288, URL: http://www.chinadrugtrials.org.cn). The C-peptide and plasma concentration of lispro 25 were analyzed using ELISA and high-performance liquid chromatography, respectively. A euglycemic clamp was used to measure the glucose infusion rate (GIR). The main PK parameters (AUC0-t and Cmax) and PD parameters (GIRmax and GIRAUC0-t) and the evaluation of bioequivalence were calculated using WinNonlin 8.3.1.Results: The quality of the clamp was approved by stable blood glucose and inhibited C-peptide levels. For PK parameters, the Cmax values of the T and R preparations were 1.40 ± 0.452 and 1.36 ± 0.418 ng·mL-1, respectively, and the AUC0–24h values were 497 ± 107 and 510 ± 86.2 ng h·mL-1, respectively. For PD parameters, GIRmax values were 4.47 ± 2.12 and 4.12 ± 1.81 mg kg·min-1, and AUCGIR0–24h values were 2,994 ± 1,232 and 2,994 ± 941 mg h·kg·min-1 for T and R, respectively. The 90% confidence intervals (CIs) for the geometric mean ratio (test/reference) of the main PK parameters (AUC0-t and Cmax) and PD parameters (GIRmax and GIRAUC0-t) in both cohorts were within the range of 80%–125%. Furthermore, there was no significant hypoglycemia and serious adverse events (SAEs) observed in this study.Conclusion: Bio-equivalence between insulin lispro (R) (Humalog®25) and insulin lispro (T) was demonstrated, with both showing good tolerance in healthy Chinese volunteers. The results provide evidence supporting the interchangeability of different drug formulations and offer more options for clinical drug use