Subnanometer-confined reaction is the frontier of catalytic chemistry, yet it is challenging to form the angstrom channels with distributed atomic catalytic centers within, and to match the internal ...mass transfer and the reactive species’ lifetimes. Here, the authors resolve these issues by applying the concept of the angstrom-confined catalytic water contaminant degradation.
•Three consistency conditions for the Cahn-Hilliard Phase-Field model are proposed.•The scheme is consistent & conservative for momentum transport at the discrete level.•The balanced-force algorithm ...is implemented to the surface force.•The proposed scheme is formally 2nd-order accurate in time and space.•The numerical solution converges to the sharp interface one.
In the present work, the Cahn-Hilliard Phase-Field model of incompressible two-phase flows is considered. Conditions needed for consistency of reduction, consistency of mass and momentum transport, and consistency of mass conservation are proposed. The mass flux in the Navier-Stokes equations is defined such that it satisfies the proposed consistency conditions. The analysis in both continuous and discrete levels shows that violation of the consistency conditions result in unphysical solutions and the inconsistent errors are proportional to the density contrast of the fluids. After considering the conservative form of the inertial term, a consistent and conservative scheme for momentum transport is developed. The balanced-force algorithm for the sharp interface model is extended to the surface force derived from the Cahn-Hilliard model. The proposed scheme is formally 2nd-order accurate in both time and space, satisfies the consistency conditions, conserves mass globally and momentum essentially, and is balanced-force, in the discrete level. Its convergence to the sharp interface solution is systematically discussed in cases including large density and viscosity ratios, surface tension, and gravity. Various two-phase flow problems with large density ratios are performed to validate and verify the proposed scheme and excellent agreements with published numerical and/or experimental results are achieved. The proposed scheme is a practical and accurate tool to study two-phase flows, especially for those including large density ratios.
The exploiting of hybrid beamforming (HBF) in massive multiple-input multiple-output (MIMO) systems can enhance the system’s sum rate while reducing power consumption and hardware costs. However, ...designing an effective hybrid beamformer is challenging, and interference between multiple users can negatively impact system performance. In this paper, we develop a scheme called Subset Optimization Algorithm-Hybrid Beamforming (SOA-HBF) that is based on the subset optimization algorithm (SOA), which effectively reduces inter-user interference by dividing the users set into subsets while optimizing the hybrid beamformer to maximize system capacity. To validate the proposed scheme, we constructed a system model that incorporates an intelligent reflecting surface (IRS) to address obstacles between the base station (BS) and the users set, enabling efficient wireless communication. Simulation results indicate that the proposed scheme outperforms the baseline by approximately 8.1% to 59.1% under identical system settings. Furthermore, the proposed scheme was applied to a classical BS–users set link without obstacles; the results show its effectiveness in both mmWave massive MIMO and IRS-assisted fully connected hybrid beamforming systems.
In the present study, a consistent and conservative Phase-Field method, including both the model and scheme, is developed for multiphase flows with an arbitrary number of immiscible and ...incompressible fluid phases. The consistency of mass conservation and the consistency of mass and momentum transport are implemented to address the issue of physically coupling the Phase-Field equation, which locates different phases, to the hydrodynamics. These two consistency conditions, as illustrated, provide the “optimal” coupling because (i) the new momentum equation resulting from them is Galilean invariant and implies the kinetic energy conservation, regardless of the details of the Phase-Field equation, and (ii) failures of satisfying the second law of thermodynamics or the consistency of reduction of the multiphase flow model only result from the same failures of the Phase-Field equation but are not due to the new momentum equation. Physical interpretation of the consistency conditions and their formulations are first provided, and general formulations that are obtained from the consistency conditions and independent of the interpretation of the velocity are summarized. Then, the present consistent and conservative multiphase flow model is completed by selecting a reduction consistent Phase-Field equation. Several novel techniques are developed to inherit the physical properties of the multiphase flows after discretization, including the gradient-based phase selection procedure, the momentum conservative method for the surface force, and the general theorems to preserve the consistency conditions on the discrete level. Equipped with those novel techniques, a consistent and conservative scheme for the present multiphase flow model is developed and analyzed. The scheme satisfies the consistency conditions, conserves the mass and momentum, and assures the summation of the volume fractions to be unity, on the fully discrete level and for an arbitrary number of phases. All those properties are numerically validated. Numerical applications demonstrate that the present model and scheme are robust and effective in studying complicated multiphase dynamics, especially for those with large-density ratios.
•Introducing a new index system to evaluate the ecological security of mineral resource-based cities in China.•Proposing an integrated method to measurement the ecological security of mineral ...resource-based cities in China.•Revealing the temporal and spatial evolution characteristics of the ecological security of mineral resource-based cities in China.•Providing a new perspective and guideline to formulate sustainable development policies.
Accurate assessments of the ecological security of mineral resource-based cities in China (MRBCCs) are one of the most important elements of improving comprehensive national security policies in the country and promoting high-quality development therein. To this end, an integrated method is proposed herein based on rough set-entropy weight method-spatial data analysis, and an ecological security assessment indicator system is constructed based on a pressure sensitivity–stability–external regulation nexus. The ecological security status of 108 MRBCCs was evaluated in multiple dimensions and based on their spatiotemporal evolution. The results show that the comprehensive ecological security of MRBCCs improved from 2010 to 2018, but it was still low. There exists strong heterogeneity in the comprehensive ecological security of different cities, and the gap will only increase over time. Additionally, the comprehensive ecological security of MRBCCs dependent on coal, petroleum, non-ferrous metal, and ferrous metal showed an upward trend from 2010 to 2018. Petroleum-dependent cities were the most stable and had the best external regulation, while comprehensive ecological security was the worst in coal-based cities. Recently, cities dependent on non-ferrous metals faced the highest ecological pressure, and both they and non-cities dependent on ferrous metals had relatively weak external regulations. Finally, the MRBCC had high levels of agglomerated ecological security, there was a strong spatial autocorrelation and promotion effect, and the agglomeration had clear spatial characteristics. The high- and low-value areas were in the eastern mineral resources and northeastern mineral resources cities, respectively. The temporal and spatial evolution characteristics of the ecological security of MRBCC are revealed in detail, providing scientific data and a quantitative reference to assist the Chinese government in accurate management of the green development of mineral resource cities.
Intratumoral accumulation of CD4
CD25
Foxp3
regulatory T (Treg) cells occurs in acute myeloid leukemia (AML), but little is known about the role of tumor cells themselves in this process. Here, we ...showed that an immune checkpoint PD-L1 expressed by AML cells promoted the conversion and expansion of Treg cells sustaining high expression of Foxp3 and PD-1 as well as a suppressive function. Furthermore, an AML cell line HEL overexpressed PD-L1 promoted the conversion and expansion of Treg cells and CD4
PD-1
Foxp3
T (PD-1
Treg) cells from the conventional CD4
T cells. CD4
CD25
PD-1
T cells secreted more IL-10 production than CD4
CD25
PD-1
T cells. IL-35, another cytokine secreted by Treg cells, promoted the proliferation of HL-60 cells and enhanced chemoresistance to cytarabine. Blockade of PD-1 signaling using anti-PD-L1 antibody dramatically impaired the generation of Treg cells and sharply retarded the progression of a murine AML model injected with C1498 cells. The frequency of intratumoral PD-1
Treg cells was capable of predicting patient survival in patients with AML. In conclusion, our data suggest that PD-L1 expression by AML cells may directly drive Treg cell expansion as a mechanism of immune evasion and the frequency of PD-1
Treg cells is a potential prognostic predictor in patients with AML.
Microbial volatiles play an expedient role in the agricultural ecological system by enhancing plant growth and inducing systemic resistance against plant pathogens, without causing hazardous effects ...on the environment. To explore the effects of VOCs of Ralstonia solanacearum TBBS1 (Rs) on tobacco plant growth and on plant growth promoting efficiency of VOCs produced by Bacillus subtilis SYST2, experiments were conducted both in vitro and in planta.
The VOCs produced by SYST2 significantly enhanced the plant growth and induced the systemic resistance (ISR) against wilt pathogen Rs in all experiments. The SYST2-VOCs significantly increased PPO and PAL activity and over-expressed the genes relating to expansin, wilt resistance, and plant defense while repressed the genes relating to ethylene production. More interestingly, VOCs produced by pathogen, Rs had no significant effect on plant growth; however, Rs-VOCs decreased the growth promoting potential of SYST2-VOCs when plants were exposed to VOCs produced by both SYST2 and Rs. The co-culture of SYST2 and Rs revealed that they inhibited the growth of each other; however, the inhibition of Rs by SYST2-VOCs appeared to be greater than that of SYST2 by Rs-VOCs.
Our findings provide new insights regarding the interaction among SYST2-VOCs, Rs-VOCs and plant, resulting in growth promotion and induced systemic resistance against the bacterial wilt pathogen Rs. This is the first report of the effect of VOCs produced by pathogenic microorganism on plant growth and on plant growth-promoting and systemic resistance-inducing potential of PGPR strain SYST2.
Transparent hydrogels are key materials for many applications, such as contact lens, imperceptible soft robotics and invisible wearable devices. Introducing large and engineerable optical anisotropy ...offers great prospect for endowing them with extra birefringence-based functions and exploiting their applications in see-through flexible polarization optics. However, existing transparent hydrogels suffer from limitation of low and/or non-fine engineerable birefringence. Here, we invent a transparent magneto-birefringence hydrogel with large and finely engineerable optical anisotropy. The large optical anisotropy factor of the embedded magnetic two-dimensional material gives rise to the large magneto-birefringence of the hydrogel in the transparent condition of ultra-low concentration, which is several orders of magnitude larger than usual transparent magnetic hydrogels. High transparency, large and tunable optical anisotropy cooperatively permit the magnetic patterning of interference colours in the hydrogel. The hydrogel also shows mechanochromic and thermochromic property. Our finding provides an entry point for applying hydrogel in optical anisotropy and colour centred fields, with several proof-of-concept applications been demonstrated.
An implantable stacked planar inverted-F antenna (PIFA) for biotelemetric communication in the 402–405 MHz Medical Implant Communications Service (MICS) frequency band is designed and fabricated. ...With the proposed PIFA structure, a slot on each radiating patch was embedded, resulting in a size reduction of 0.013 λ and a compact size of 10 × 10 × 1.905 mm3. Both in vitro and in vivo experiments verified the simulation performance with characteristics of −10 dB bandwidth of 29 MHz, radiation efficiency of 0.9%, and a maximum far-field gain of −18.8 dB. We calculated the safety power delivered to the antenna using the specific absorption rate (SAR) limitation standard. Compared to other implantable antennas for biotelemetry, this antenna performs comparably and has a smaller size. This design would further develop implantable medical devices that communicate in the MICS band.
Brain-computer interface (BCI) based on electroencephalogram (EEG) signals can provide a way for human to communicate with the outside world. This approach is independent of the body's peripheral ...nerves and muscle tissue. The brain-controlled robot is a new technology based on the brain-computer interface technology and the robot control technology. This technology allows the human brain to control a robot to perform a series of actions. The processing of EEG signals plays a vital role in the technology of brain-controlled robots. In this paper, the methods of EEG signal processing in recent years are summarized. In order to better develop the EEG signal processing methods in brain-controlled robots, this paper elaborate on three parts: EEG signal pre-processing, feature extraction and feature classification. At the same time, the correlation analysis methods and research contents are introduced. The advantages and disadvantages of these methods are analyzed and compared in this paper. Finally, this article looks forward to the EEG signal processing methods in the process of brain-controlled robots.
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