Gang Chen

Time crystals constitute a novel phase of matter defined by the spontaneous breaking of timetranslation symmetry. Here we present a scheme to realize a continuous-time crystal of the vibrational phonon in the normal mode of two coupled ultra-cold ions. By utilizing two addressable standing-wave lasers and adiabatic elimination method, we generate a controllable nonlinear phonon mode with the well-designed efficient linear gain and nonlinear damping. By controlling these parameters to satisfy the phase transition conditions of Hopf bifurcation and limit cycle phase, it behaves as a stable dissipative dynamics over timescales significantly longer than the oscillation period, indicating the emergence of discrete time-translation symmetry breaking in the phonon mode, i.e., a phonon time crystal. We further numerically simulate this phonon time crystal by using accessible experimental parameters and also demonstrate a robustness to the initial thermal state and thermalization of phonon mode, spin dephasing, and the control errors of Rabi frequencies. These results provide a practical scheme for observing a time crystal in a nonlinear phonon mode and will advance the research of time crystals.

This study presents an integrated multi-scale framework for predicting gas entrainment and flow behavior in coalbed methane production systems under gas-liquid two-phase flow conditions. The approach combines three-dimensiona... | Find, read and cite all the research you need on Tech Science Press

Lyophilization (aka freeze drying) is a typical process in (bio)pharmaceutical manufacturing used for improving the stability of various drug products, including its recent applications to mRNA vaccines. While extensive efforts are dedicated to shifting the (bio)pharmaceutical industry toward continuous manufacturing, the majority of industrial-scale lyophilization is still being operated in batch mode. This article presents the first mechanistic model for a complete continuous lyophilization process, which comprehensively incorporates and describes key transport phenomena in all three steps of lyophilization, namely freezing, primary drying, and secondary drying. The proposed model considers the state-of-the-art lyophilization technology, in which vials are suspended and move continuously through the process. The validated model can accurately predict the evolution of critical process parameters, including the product temperature, ice/water fraction, sublimation front position, and concentration of bound water, for the entire process. Several applications related to model-based process design and optimization of continuous lyophilization are also demonstrated. The final model is made available as an open-source software package that can be leveraged for guiding the design and development of future continuous lyophilization processes.

It is well-known that water in both liquid and vapor phases exhibits exceptionally weak absorption of light in the visible range. Recent experiments, however, have demonstrated that at the liquid-air interface, absorption in the visible range is drastically increased. This increased absorption results in a rate of evaporation that exceeds the theoretical thermal limit by between two and five times. Curiously, the evaporation rate peaks at green wavelengths of light, while no corresponding absorptance peak has been observed. Experiments suggest that photons can cleave off clusters of water molecules at the surface, but no clear theoretical model has yet been proposed to explain how this is possible. This paper aims to present such a model and explain this surprising and important phenomenon.

We investigate the effective potential and scattering length of ultracold polar molecules under different shielding techniques. First, we derive the effective potential for two polar molecules in the presence of (i) an elliptical polarization field alone, (ii) combined elliptical and linear polarization fields, and (iii) combined elliptical polarization and static fields. The effective potential is then expressed as a sum of a zero-range contact interaction and a long-range dipolar interaction under the Born approximation. We find that the methods (i) and (ii) only partially suppress attractive interactions, while the method (ii) allows for the construction of bound states with different polarization shapes. The last shielding method (iii) can achieve complete cancellation of residual attractive forces [Micheli et al., Phys. Rev. A 76, 043604 (2007); Gorshkov et al., Phys. Rev. Lett. 101, 073201 (2008)], which is particularly significant for maintaining quantum degeneracy in ultracold dipolar systems. Our results provide a comprehensive understanding of the effective potential and scattering length of shielding polar molecules, which is crucial for studying many-body physics in ultracold dipolar systems.

To address wellbore integrity issues (especially casing strength concerns) of oil and gas wells threatened by overburden movement in coal mine goafs, this study takes a gas well in the goaf of Yanchang Gas Field as the research object. Using FLAC3D 7.0 software, a 3D coupling model of “casing-cement sheath-formation-goaf” is established to systematically analyze the effects of goaf presence, convergence criteria, casing wall thickness/layer count, and cement slurry density on casing stress while conducting wellbore structure optimization. Key research results are as follows: (1) Overburden movement concentrates the maximum casing stress near the goaf, with the surface casing stress being 7–8 times higher than that in the absence of a goaf, serving as the core object of stress control; (2) A convergence criterion of 10−4 balances calculation accuracy and efficiency, where the maximum Von Mises equivalent stress of the surface casing differs by only 0.98% compared with that under a convergence criterion of 10−6; (3) Increasing casing layers is more effective than thickening walls or upgrading steel grade: three-layer casing reduces surface casing stress by 23.4% compared with two-layer casing, and all casing safety factors meet the standards; (4) The casing stress is minimized when the cement slurry density is 1800–1900 kg/m3 (with a minimum of 325.79 MPa), while excessively low or high density will lead to increased stress. The optimized wellbore structure provides key references for the design of gas wells in goaf areas.

Abstract Angle‐enabled wavefront sensing based on metasurface can realize high‐spatial‐resolution wavefront reconstruction without requiring reference‐beam interference, which has great potential in applications in various fields ranging from biological cell characterization to surface metrology. However, the current metasurface wavefront encoding scenario exhibits weak modulation capabilities with an oversimplified angular modulation function, resulting in a limited angular resolution. Here, a wavefront sensor based on random wavefront coding with a diverse angle response function, achieved through a diffractive optical element (DOE), is proposed, which can simultaneously provide a large dynamic range, high spatial resolution, and high angular resolution. By experimentally calibrating the mapping between DOE diffraction patterns and incident angles, one can precisely decode the local incident angles. Combined with zonal wavefront reconstruction algorithms, the unknown wavefront can be reconstructed accurately. Owing to the drastically improved resolution, the wavefront sensor can be used for quantitative phase imaging, which shows a good capability in surface topography measurement for both static and dynamically evolving samples. The method provides valuable insights for high‐resolution wavefront sensing and quantitative phase imaging.

Abstract The rational design of composition and microstructure is a proven strategy for developing multifunctional high‐performance electromagnetic wave (EMW) absorbers. In this study, a sandwich‐structured multilayer nanoplate‐like Bi 2 Fe 4 O 9 @Polypyrrole (BFO@PPy) heterostructure was successfully designed and fabricated using an efficient microwave hydrothermal method and an in situ polymerization process. Specifically, Bi 2 Fe 4 O 9 enhances the chemical activity of ammonium persulfate, which in turn initiates the polymerization of pyrrole monomers, resulting in the formation of BFO@PPy heterostructures. The thickness of the PPy coating layer in the BFO@PPy composite can be precisely controlled at the nanoscale, optimizing electromagnetic parameters, conduction losses and interface polarization loss. The fabricated BFO@PPy composite achieves a minimum reflection loss (RL min ) of −57.8 dB at a thickness of 2.5 mm and an effective absorption bandwidth (EAB) of 6.96 GHz. Furthermore, the EMW absorption performance and mechanism were systematically validated through theoretical calculations, radar cross‐sectional simulations (RCS), and first‐principles analysis. Notably, the RCS simulation of a 1:1 scale F‐22 Raptor fighter model provides a realistic evaluation of the composite’s EMW absorption potential in military applications. The efficient fabrication method and superior electromagnetic absorption performance make BFO@PPy a promising candidate for use in complex electromagnetic environments and military domains. Additionally, the BFO@PPy composite exhibits rapid electrothermal conversion at a low voltage (3 V), achieving active infrared camouflage within a controllable temperature range, further highlighting its multifunctional properties.

The large design space of metal-organic frameworks (MOFs) has prompted the utilization of deep learning to drive material design. Nonetheless, the prediction of key thermodynamic properties, such as heat of adsorption ( $$\Delta {H}_{{\rm{ads}}}$$ ), remains largely unexplored for CO2 adsorption in MOFs. Herein, we present IsothermNet, a high-throughput graph neural network designed to estimate uptake and $$\Delta {H}_{{\rm{ads}}}$$ over 0–50 bars, enabling high-quality full isotherm reconstruction (PCC: 0.73–0.95 [uptake], 0.76–0.88 [ $$\Delta {H}_{{\rm{ads}}}$$ ]). We further bridged these adsorption properties to uptake behaviors (i.e., isotherm shapes/types) and structural information by performing detailed ablation studies to investigate the relative importance of local and global features in relation to predictive performance. This comparative analysis facilitated the discovery of a (1) physically-interpretable and (2) analytically-derived universal descriptor set capable of illustrating interdependencies between easily-computed, accessible textural information and extrinsic adsorption properties. When used cooperatively with IsothermNet, these descriptors enable efficient material screening, accelerating high-performance MOF discovery for CO2 capture.

This study presents a technique to increase the turn‐on voltage (V on ) of IGZO thin‐Film transistors (TFTs) by reducing the thickness of the active layer. These bottom‐gate, etch‐stop structure TFTs were fabricated on a Generation 3.5 production line. Reducing the IGZO thickness from 60 nm to 20 nm increased Von from ‐6.2 V to 4.3 V, attributed to the enhanced oxidation of the thinner IGZO layer, where oxygen more effectively penetrates and oxidizes defects. The thinner active layer also exhibited a significant increase in output resistance. Additionally, the thinner active layer demonstrated improved thermal stability. Following nitrogen annealing at 350°C, the negative drift in Von was reduced to less than 4 V for the 20 nm IGZO TFT, whereas the 60 nm IGZO TFT experienced severe hydrogen accumulation, resulting in short‐circuiting. This improvement is attributed to the enhanced diffusion of hydrogen out of the thinner IGZO layer. These findings help enable the development of enhancement‐mode IGZO TFTs.

Long-term sports and rehabilitation training require effective monitoring of muscle fatigue and recovery. Blood lactate fails to accurately reflect muscle fatigue level over extended period. Sweat lactate is a promising alternative, but its potential for assessing multi-day muscle fatigue remains unexplored. Here, we present a method for assessing multi-day muscle fatigue and recovery utilizing a high-performance, battery-free, and practical sweat lactate sensing patch. The wearable patch integrates replaceable lactate sensors and electronics that can be powered and transmits data wirelessly via near-field communication. A high-performance lactate sensor based on a novel three-dimensional microstructured electrode with a Pt/CNT-Pt composite was investigated. The synergistic effect between the electrode material and structure imparts an ultra-high sensitivity of 9.76 μA mM-1 cm-2 within a sufficient linear range of 0.1-30 mM. The electrode features a through-hole array to ensure sufficient oxygen supply for enzyme catalysis during skin attachment, ensuring reliable signal output. The sweat lactate profiles under different conditions were studied. Multi-day exercise experiments demonstrate a trend in initial sweat lactate levels, which is absent in initial blood lactate levels. Monitoring sweat lactate during rehabilitation training can also guide training programs. The feasibility of assessing muscle fatigue during multi-day exercise through sweat lactate levels was demonstrated. This work presented a practical method to determine lactate response and muscle fatigue level during exercise towards generating personalized training plans.

BACKGROUND Hepatocellular carcinoma (HCC) is at the forefront of the global spectrum of cancer incidence and mortality, with conventional therapies like tyrosine kinase inhibitors limited by resistance. Recent studies have highlighted the promising anticancer effects of nitidine chloride (NC) against HCC. SAC3 domain containing 1 (SAC3D1) is critical for centrosome replication and spindle formation. However, research on SAC3D1 in HCC and NC remains limited. AIM To investigate the mechanisms underlying SAC3D1’s role in HCC progression and evaluated its potential as a therapeutic target of NC. METHODS RNA sequencing (RNA-seq) identified SAC3D1 expression changes in HCC cells after NC treatment. Molecular docking was further employed to validate the direct binding between NC and SAC3D1. Additionally, HCC multicenter data (The Cancer Genome Atlas_GTEx, ArrayExpress), pathway analysis, Pearson correlation analysis and SAC3D1 in vitro knockdown experiments were integrated to explore the molecular mechanisms underlying SAC3D1's involvement in HCC progression. RESULTS RNA-seq showed that NC treatment significantly downregulated SAC3D1 expression [log2(fold change) = - 0.95, P < 0.05], with molecular docking revealing that NC directly bound to SAC3D1 proteins (binding energy: -9.7 kcal/mol). Enrichment analysis showed that most pathways were closely related to the cell cycle. Pearson correlation analysis indicated that SAC3D1 and cell cycle genes were significantly positively correlated(correlation coefficient ≥ 0.3, P < 0.05). SAC3D1 knockdown inhibited HCC cell invasion, migration, and proliferation by arresting cells in the S and G2/M phases. Flow cytometry confirmed that after SAC3D1 knockdown, the early and total apoptosis percentage of HCC cells decreased, while the late apoptosis percentage increased. CONCLUSION As a potential target of NC, SAC3D1 may inhibit HCC progression through cell cycle regulation following its downregulation by NC.

The refractive index is one of the most important optical parameters of optical thin films. Optical films with a low refractive index can effectively reduce the residual reflection on the film surface, which is one of the most important parameters pursued by scholars. In this research, SiO2 thin films with a low refractive index and nanocolumnar structures were prepared by oblique angle deposition (OAD). The SiO2 thin films deposited at different inclination angles were prepared using the electron beam evaporative deposition method. The single-layer film samples were measured by ellipsometry, infrared spectrometry, scanning electron microscopy (SEM), and atomic force microscopy (AFM). The experimental results demonstrated that at an inclination angle of 85°, the average refractive index of the film decreased to 1.30 in the 350–1300 nm wavelength range. Additionally, the film deposited on one side of a crystalline Al2O3 substrate achieved a transmittance of 92.1% in the 350–1500 nm wavelength range and the residual reflectance was reduced by 0.7%.

This paper presents a novel design for electromagnetic wave (EMW) absorbing materials, focusing on a composite heterostructure of La-doped Bi 2 Fe 4 O 9 (BLFO) and polypyrrole (PPy) with a truncated pyramid nanostructure. This research aims to overcome the limitations of traditional EMW absorbers by leveraging the unique nano-morphology and properties of the BLFO@PPy composite. The unique microstructure of BLFO endows the composite with abundant interface polarization, while PPy significantly enhances the conduction loss. The resulting synergistic effect substantially improves the EMW absorption performance. The study demonstrates that La doping in Bi 2 Fe 4 O 9 leads to the formation of a truncated pyramid nanosheet array. When combined with PPy, this structure significantly enhances interface polarization, scattering, and absorption of EMWs. Specifically, the sample BLFO@PPy-3 exhibits superior EMW absorption performance, achieving a minimum reflection loss ( RL min ) of − 64.20 dB and an effective absorption bandwidth (EAB) of 7.20 GHz. The effectiveness of this design is validated through comprehensive electromagnetic simulations. The simulation of the radar cross-section (RCS) indicates that BLFO@PPy-3 significantly enhances the stealth performance of unmanned combat aerial vehicles (UCAVs). Furthermore, the paper investigates the thermal conductivity properties of the composite, highlighting its potential for thermal management alongside EMW absorption. By optimizing the PPy content, the thermal properties of the composite can be precisely controlled, ensuring stable performance in practical applications. These findings offer valuable insights into the design and development of next-generation multifunctional EMW absorbing materials for diverse military and industrial applications.

It is well-known that evaporation can lead to cooling. However, little is known that evaporation can actually create a refrigeration effect, i.e., the vapor phase temperature can drop below the temperature of the cooling wall. This possibility was recently pointed out via modeling based on an approximate quasi-continuum approach. This work examines this effect rigorously by studying evaporation and condensation between two parallel plates by coupling the solution of the Boltzmann transport equation in the vapor phase with the continuum treatments in both liquid films. Numerical results show that the vapor phase temperature at the evaporating side can be much lower than the coldest wall temperature at the condensing surface, reaffirming the evaporative refrigeration effect. The present work further reveals that this effect is caused by two mechanisms. While the dominant mechanism is the asymmetry in the molecular distribution between the outgoing and the incoming molecules at the interface, additional cooling occurs within the Knudsen layer due to the sudden expansion, similar to the Joule-Thomson effect, although with subtle differences in that the interfacial expansion is not an isenthalpic process. The impacts of key parameters, including liquid thickness, Knudsen number, and accommodation coefficient, are investigated. The numerical simulation shows that with a thicker vapor, a thinner liquid film, and a larger accommodation coefficient, leads to stronger evaporative refrigeration effect. This work will motivate future experiments to further confirm this prediction and explore its potential applications in air-conditioning, refrigeration, and membrane distillation.

Droplets are ubiquitous and necessary in natural phenomena, daily life, and industrial processes, which play a crucial role in many fields. So, the manipulation of droplets has been extensively investigated for meeting widespread applications, consequently, a great deal of progresses have been achieved across multiple disciplines ranging from chemistry to physics, material, biological, and energy science. For example, microdroplets have been utilized as reactors, colorimetric or electrochemical sensors, drug-delivery carriers, and energy harvesters. Moreover, droplet manipulation is the basis in both fundamental researches and practical applications, especially the combination of smart materials and external fields for achieving multifunctional applications of droplets. In view of this background, this review initiates discussion of the manipulation strategies of droplets including Laplace pressure, wettability gradients, electric field, magnetic force, light and temperature. Thereafter, based on their manipulation strategies, this review mainly summarizes the applications of droplets in the fields of robot, green energy, sensors, biomedical treatments, microreactors and chemical reactions. Application related basic concepts, theories, principles and progresses also have been introduced. Finally, this review addresses the challenges of manipulation and applications of droplets and provides the potential directions for their future development. By presenting these results, we aim to provide a comprehensive overview of water droplets and establish a unified framework that guides the development of droplets in various fields.

The lower bound of estimated precision for a coherent parameter unitarily encoded in closed systems has been obtained, and such a lower bound is inversely proportional to the fluctuation of the encoding operator. In this paper, we first derive some general results regarding the lower bound of estimated precision for a dissipative parameter, which is nonunitarily encoded in open systems, by combining the law of error propagation and the non-Hermitian linear response theory. This lower bound is related to the correlation of the encoding dissipative operator and the evolution time. We next demonstrate the utility of our general results by considering three different kinds of nonunitary encoding processes, including particle loss, relaxation, and dephasing. We finally compare the lower bound with the quantum Fisher information obtained by tomography and find they are consistent in the regime where the non-Hermitian linear response applies. This lower bound can guide us to find the optimal initial states and detecting operators to significantly simplify the measurement process.

Glioblastoma, characterized by rapid proliferation and invasiveness, is largely resistant to current treatment modalities. A major obstacle is the blood-brain barrier (BBB), which restricts the delivery of therapeutic agents as well as the infiltration of effective immune cells into glioblastoma. In this study, we developed an injectable oxidized high-amylose starch hydrogel (OHASM) to serve as a biomaterial scaffold for the delivery of macrophages and macrophage-polarizing drugs, aiming to bypass the BBB and enhance glioblastoma treatment. The in vitro and in vivo experiments confirmed the efficacy of the hydrogel in loading and delivering macrophages and polarizing drugs against glioblastoma. Additionally, the hydrogel's interconnected porous structure was conducive to cellular growth and activity, and its slow release of therapeutics contributed to the extended survival of treated mice in a mouse GL261 glioblastoma tumor model. The immunological mechanisms underlying the therapeutic efficacy were further elucidated, revealing the potential of the hydrogel system to modulate macrophage polarization and induce apoptosis in tumor cells via the poly ADP-ribose polymerase (PARP) pathway. The study underscores the potential of the hydrogel-based macrophage delivery strategy as an effective and safe treatment for glioblastoma, offering a promising avenue for clinical management of this aggressive brain cancer.