Lithium-rich layered structure cathode materials are arousing significant attention in the next-generation commercial lithium ion batteries owing to their high capacity and energy density. However, ...the poor rate performance and inferior cycle stability stand in the way of its large-scale applications. In this study, we pioneer a novel cation/anion (sodium/fluorine) co-doping approach to address the above issues for lithium rich Li1.2Ni0.2Mn0.6O2 cathode. Consequently, the cation/anion co-doped cathode material could keep the advantages of both cation (sodium) and anion (fluorine), which can significantly enhance the stability by suppressing the phase transformation from layered to spinel structure and rate performance through decreasing resistance of Li diffusion and the electrons migration. The co-doped Li1.12Na0.08Ni0.2Mn0.6O1.95F0.05 exhibits an excellent cycling stability (100% after 100 cycles at 0.2 C) and a superior rate performance (167 mAh g−1 at 5 C). The mechanism of the dramatic improvement is also systematic investigated for the first time. Furthermore, we also believe that the cation/anion co-doping approach could be employed to improve the performance of other classes of layered cathode materials.
A novel cation/anion (sodium/fluorine) co-doping approach is proposed to improve the electrochemical performance and structural stability of lithium-rich manganese-based cathode Li1.2Ni0.2Mn0.6O2 for advanced lithium ion batteries. Display omitted
•We proposed a novel cation/anion (sodium/fluorine) co-doping methode for lithium rich Li1.2Ni0.2Mn0.6O2 cathode.•The cation/anion (sodium/fluorine) co-doping mechanism was studied in-depth.•Excellent cycling stability and superior rate performance have been achieved with the co-doping process.
In this study, we obtained the intensity and orbital angular momentum (OAM) spectral distribution of the scattering fields of vortex electromagnetic beams illuminating electrically large targets ...composed of different materials. We used the angular spectral decomposition method to decompose a vortex beam into plane waves in the spectral domain at different elevations and azimuths. We combined this method with the physical optics algorithm to calculate the scattering field distribution. The OAM spectra of the scattering field along different observation radii were analyzed using the spiral spectrum expansion method. The numerical results indicate that for beams with different parameters (such as polarization, topological charge, half-cone angle, and frequency) and targets with different characteristics (such as composition), the scattering field intensity distribution and OAM spectral characteristics varied considerably. When the beam parameters change, the results of scattering from different materials show similar changing trends. Compared with beams scattered by uncoated metal and dielectric targets, the scattering field of the coating target can better maintain the shape and OAM mode of beams from the incident field. The scattering characteristics of metal targets were the most sensitive to beam-parameter changes. The relationship between the beam parameters, target parameters, the scattering field intensity, and the OAM spectra of the scattering field was constructed, confirming that the spiral spectrum of the scattering field carries the target information. These findings can be used in remote sensing engineering to supplement existing radar imaging, laying the foundation for further identification of beam or target parameters.
The integration of a renewable energy and hybrid energy storage system (HESS) into electrified railways to build an electric railway smart microgrid system (ERSMS) is beneficial for reducing fossil ...fuel consumption and minimizing energy waste. However, the fluctuations of renewable energy generation and traction load challenge the effectiveness of the energy management for such a complex system. In this work, an energy management strategy is proposed which firstly decomposes the renewable energy into low-frequency and high-frequency components by an integrated empirical mode decomposition (IEMD). Then, a two-stage energy distribution approach is utilized to appropriately distribute the energy flow in the ERSMS. Finally, the feasibility and effectiveness of the proposed solution are validated through case study.
Polarization measurements allow one to enhance the imaging contrast of superficial tissues and obtain new polarization sensitive parameters for better descriptions of the micro- and macro- structural ...and optical properties of complex tissues. Since the majority of cancers originate in the epithelial layer, probing the morphological and pathological changes in the superficial tissues using an expended parameter set with improved contrast will assist in early clinical detection of cancers. We carry out Mueller matrix imaging on different cancerous tissues to look for cancer specific features. Using proper scattering models and Monte Carlo simulations, we examine the relationship between the microstructures of the samples, which are represented by the parameters of the scattering model and the characteristic features of the Mueller matrix. This study gives new clues on the contrast mechanisms of polarization sensitive measurements for different cancers and may provide new diagnostic techniques for clinical applications.
In the drilling industry, it is of great significance to accurately predict the drag coefficient and settling velocity of drill cuttings falling in the non-Newtonian drilling fluid. However, the ...irregular shape of drill cuttings and the non-Newtonian rheological properties of drilling fluid (e.g., shear-thinning and yield stress behavior) make it challenging to predict the settling velocity. In this study, the velocity of particle settlement was studied by a visual device and high-speed camera system. Experimental data of the free settlement of 224 irregular drilling cuttings and 105 spherical particles in the Herschel–Bulkley fluid were obtained. A mechanical model dependent on the force balance of settlement particles was adopted to conduct a detailed statistical analysis of the experimental results, and a prediction model of the drag coefficient of spherical particles in the Herschel–Bulkley fluid was established. A two-dimensional shape description parameter is introduced to establish a model for predicting the drag coefficient of irregular-shaped cuttings in a Herschel–Bulkley fluid. The model has high prediction accuracy for the settling velocity of irregular shale cuttings in Herschel–Bulkley fluid. The average relative error is 7.14%, verifying the model’s accuracy.
Mueller matrices can be used as a powerful tool to probe qualitatively the microstructures of biological tissues. Certain transformation processes can provide new sets of parameters which are ...functions of the Mueller matrix elements but represent more explicitly the characteristic features of the sample. In this paper, we take the backscattering Mueller matrices of a group of tissues with distinctive structural properties. Using both experiments and Monte Carlo simulations, we demonstrate qualitatively the characteristic features of Mueller matrices corresponding to different structural and optical properties. We also calculate two sets of transformed polarization parameters using the Mueller matrix transformation (MMT) and Mueller matrix polar decomposition (MMPD) techniques. We demonstrate that the new parameters can separate the effects due to sample orientation and present quantitatively certain characteristic features of these tissues. Finally, we apply the transformed polarization parameters to the unstained human cervix cancerous tissues. Preliminary results show that the transformed polarization parameters can provide characteristic information to distinguish the cancerous and healthy tissues.
This paper proposes modelling on the transmission torque of an eddy‐current axial magnetic coupling (EAMC) considering the thermal effect. A new and simple equivalent reluctance network is ...established to obtain the magnetic flux density based on the two‐dimensional (2D) finite‐element analysis. Furthermore, the expressions of the transmission torque and the thermal loss are derived by establishing the computational coordinate system for the conductor sheet (CS) eddy current. Then, a simple and effective thermal network considering different convective heat transfer modes is presented to obtain the temperature rise, and the influence of temperature on some key parameters is given to correct the transmission torque. Furthermore, the proposed modelling is in good agreement with the three‐dimensional (3D) finite‐element method (FEM) and experiments under normal working conditions. Moreover, some suggestions for the design and optimization of EAMCs are provided.
When antibiotic-resistant pathogenic bacteria pose a high threat to human health, bacterial multidrug efflux pumps become major contributors to the high-level antibiotic resistance in most ...microorganisms. Since traditional antibiotics are still indispensable currently, we report a dual drug delivery system to maximize the antibacterial efficacy of antibiotics by inhibiting efflux pumps in bacteria before their exposure to antibiotics. In this research, a microsphere/hydrogel composite was constructed from ciprofloxacin (Cip)-loaded poly (lactic-co-glycolic acid) (PLGA) microspheres and ginsenoside Rh2 (G-Rh2) dispersed thermo-sensitive hydrogel to treat skin infections. In vitro drug release studies indicated that while G-Rh2 in hydrogel presented a faster and short-term release manner to rapidly inhibit the NorA efflux pumps, Cip showed a sustained and long-term release behavior to provide a local high concentration gradient for facilitating drug percutaneous penetration. The combination of Cip and G-Rh2 demonstrated a high degree of synergism against both methicillin-sensitive Staphylococcus aureus (MSSA) and methicillin-resistant Staphylococcus aureus (MRSA), hence significantly improving their in vitro antibacterial activity and efficiency. Moreover, the antibacterial performance of the microsphere/hydrogel composite with a sequential release profile is superior to that of other formulations in mouse model of MRSA skin infections, indicating its great potential to treat antibiotic-resistant skin infections.
Background Hemorrhagic Fever with Renal Syndrome (HFRS) continues to pose a significant public health threat to the well-being of the population. Given that the spread of HFRS is susceptible to ...meteorological factors, we aim to probe into the meteorological drivers of HFRS. Thus, novel techniques that can discern time-delayed non-linear relationships from nonlinear dynamical systems are compulsory. Methods We analyze the epidemiological features of HFRS in Weifang City, 2011-2020, via the employment of the Empirical Dynamic Modeling (EDM) method. Our analysis delves into the intricate web of time-delayed non-linear associations between meteorological factors and HFRS. Additionally, we investigate the repercussions of minor perturbations in meteorological variables on future HFRS incidence. Results A total of 2515 HFRS cases were reported in Weifang from 2011 to 2020. The number of cases per week was 4.81, and the average weekly incidence was 0.52 per 1,000,000. The propagation of HFRS is significantly impacted by the mean weekly temperature, relative humidity, cumulative rainfall, and wind speed, and the rhoCCM converges to 0.55,0.48,0.38 and 0.39, respectively. The graphical representation of the relationship between temperature (lagged by 2 weeks) and the incidence of HFRS exhibits an inverted U-shaped curve, whereby the incidence of HFRS culminates as the temperature reaches 10 °C. Moreover, temperature, relative humidity, cumulative rainfall, and wind speed exhibit a positive correlation with HFRS incidence, with a time lag of 4-6 months. Conclusions Our discoveries suggest that meteorological factors can drive the transmission of HFRS both at a macroscopic and microscopic scale. Prospective alterations in meteorological conditions, for instance, elevations in temperature, relative humidity, and precipitation will instigate an upsurge in the incidence of HFRS after 4-6 months, and thus, timely public health measures should be taken to mitigate these changes.
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