Thickness- and Field-Dependent Magnetic Domain Evolution in van der Waals Fe3GaTe2.

The discovery of room-temperature ferromagnetism in van der Waals (vdW) materials opens new avenues for exploring low-dimensional magnetism and its applications in spintronics. Recently, the observation of the room-temperature topological Hall effect in the vdW ferromagnet Fe3GaTe2 suggests the possible existence of room-temperature skyrmions, yet skyrmions have not been directly observed. In this study, real-space imaging was employed to investigate the domain evolution of the labyrinth and skyrmion structure. First, Néel-type skyrmions can be created at room temperature. In addition, the influence of flake thickness and external magnetic field (during field cooling) on both labyrinth domains and the skyrmion lattice is unveiled. Due to the competition between magnetic anisotropy and dipole interactions, the specimen thickness significantly influences the density of skyrmions. These findings demonstrate that Fe3GaTe2 can host room-temperature skyrmions of various sizes, opening up avenues for further study of magnetic topological textures at room temperature.

Thrust Vectoring Control of a Novel Tilt-Rotor UAV Based on Backstepping Sliding Model Method.

In this paper, a control method of a novel tilt-rotor UAV with a blended wing body layout is studied. The novel UAV is capable of vertical take-off and landing and has strong stealth capabilities that can be applied to carrier-borne reconnaissance aircraft. However, the high aspect ratio of blended wing body UAVs leads to a wingtip or oar-tip touchdown problem when adopting the conventional position-attitude control (CPAC) scheme with a large crosswind disturbance. Moreover, when the UAV is subject to interference during reconnaissance, aerial photography, and landing missions, the conventional scheme cannot provide both attitude stability and track accuracy. First, a direct thrust vectoring control (DTVC) scheme is proposed. The control authority of the rotor tilt mechanism was added to enable the decoupling of the attitude and trajectory and to improve the response rate and response bandwidth of the flight trajectory. Second, considering the problems of strong couplings and parameter uncertainties and the nonlinear features and mismatched perturbations that are inevitable in the tilt-rotor, we designed a robust UAV controller based on the backstepping sliding mode control method and determined the stability of the control system through the Lyapunov function. Finally, in the case of crosswire interference during vertical takeoff and landing and the aerial photography missions of the UAV, the numerical simulation of the CPAC scheme and the DTVC scheme was carried out, respectively, and the Monte Carlo random test method was introduced to conduct the statistical test of the landing accuracy. The simulation results show that the DTVC scheme improves the landing accuracy and speed compared to the CAPC scheme and decouples the position control loop from the attitude control loop, finally enabling the UAV to complete the flight control in the VTOL phase.

Tungstate-mediated In-situ Passivation of Grain Boundary Grooves in Perovskite Solar Cells.

Possessed with advantageous optoelectronic properties, perovskites have boosted the rapid development of solution-processed solar cells. The performance of perovskite solar cells (PSCs) is significantly weakened by the carrier loss at grain boundary grooves (GBGs); however, it receives limited attention and there lacks effective approach to solve this issue. Herein, for the first time, we constructed the tungstate/perovskite heterointerface via a "two step" in situ reaction approach that provides effective defect passivation and ensures efficient carrier dynamics at the GBGs. The exposed perovskite at grain boundaries is converted to wide-band-gap PbWO4 via an in-situ reaction between Pb2+ and tungstate ions, which passivate defects due to the strong ionic bonding. Moreover, recombination loss is further suppressed via the heterointerface energetics modification based on an additional transformation from PbWO4 to CaWO4 . PSCs based on this groove modification strategy showed good universality in both normal and inverted structure, with an improved efficiency of 23.25 % in the n-i-p device and 23.33 % in the p-i-n device. Stable power output of the modified device could maintain 91.7 % after around 1100 h, and the device efficiency could retain 92.5 % after aging in air for around 2110 h, and 93.1 % after aging at 85 °C in N2 for 972 h.

Spinal microglial activation promotes perioperative social defeat stress-induced prolonged postoperative pain in a sex-dependent manner.

Prolonged postsurgical pain, which is associated with multiple risk factors in the perioperative stage, is a common medical and social problem worldwide. Suitable animal models should be established to elucidate the mechanisms underlying the perioperative prolonged postsurgical pain. In this study, standard and modified social defeat stress mice models, including chronic social defeat stress (CSDS), chronic nondiscriminatory social defeat stress (CNSDS) and vicarious social defeat stress (VSDS), were applied to explore the effect of perioperative social defeat stress on postsurgical pain in male and female mice. Our results showed that exposure to preoperative CSDS could induce prolonged postsurgical pain in defeated mice regardless of susceptibility or resilience differentiated by the social interaction test. Similar prolongation of incision-induced mechanical hypersensitivity was also observed in both sexes upon exposing to CNSDS or VSDS in the preoperative period. Moreover, we found that using the modified CNSDS or VSDS models at different recovery stages after surgery could still promote abnormal pain without sex differences. Further studies revealed the key role of spinal microglial activation in the stress-induced transition from acute to prolonged postoperative pain in male but not female mice. Together, these data indicate that perioperative social defeat stress is a vital risk factor for developing prolonged postoperative pain in both sexes, but the promotion of stress-induced prolonged postoperative pain by spinal microglial activation is sexually dimorphic in mice.

Study of Modeling and Optimal Take-Off Scheme for a Novel Tilt-Rotor UAV.

The optimal trajectory planning for a novel tilt-rotor unmanned aerial vehicle (UAV) in different take-off schemes was studied. A novel tilt-rotor UAV that possesses characteristics of both tilt-rotors and a blended wing body is introduced. The aerodynamic modeling of the rotor based on blade element momentum theory (BEMT) is established. An analytical method for determining the taking-off envelope of tilt angle versus airspeed is presented. A novel takeoff-tilting scheme, namely tilting take-off (TTO), is developed, and its optimal trajectory is designed based on the direct collocation method. Parameters such as the rotor thrust, tilt angle of rotor and angle of attack are chosen as control variables, and the forward velocity, vertical velocity and altitude are selected as state variables. The time and the energy consumption are considered in the performance optimization indexes. The optimal trajectories of the TTO scheme and other conventional schemes including vertical take-off (VTO) and short take-off (STO) are compared and analyzed. Simulation results indicate that the TTO scheme consumes 47 percent less time and 75 percent less energy than the VTO scheme. Moreover, with minor differences in time and energy consumption compared to the STO scheme, but without the need for sliding distance, TTO is the optimal take-off scheme to satisfy the flight constraints of a novel tilt-rotor UAV.

UAV Swarm Navigation Using Dynamic Adaptive Kalman Filter and Network Navigation.

Aiming to improve the positioning accuracy of an unmanned aerial vehicle (UAV) swarm under different scenarios, a two-case navigation scheme is proposed and simulated. First, when the Global Navigation Satellite System (GNSS) is available, the inertial navigation system (INS)/GNSS-integrated system based on the Kalman Filter (KF) plays a key role for each UAV in accurate navigation. Considering that Kalman filter's process noise covariance matrix Q and observation noise covariance matrix R affect the navigation accuracy, this paper proposes a dynamic adaptive Kalman filter (DAKF) which introduces ensemble empirical mode decomposition (EEMD) to determine R and adjust Q adaptively, avoiding the degradation and divergence caused by an unknown or inaccurate noise model. Second, a network navigation algorithm (NNA) is employed when GNSS outages happen and the INS/GNSS-integrated system is not available. Distance information among all UAVs in the swarm is adopted to compensate the INS position errors. Finally, simulations are conducted to validate the effectiveness of the proposed method, results showing that DAKF improves the positioning accuracy of a single UAV by 30-50%, and NNA increases the positioning accuracy of a swarm by 93%.

Thickness-Dependent In-Plane Polarization and Structural Phase Transition in van der Waals Ferroelectric CuInP2 S6.

van der Waals (vdW) layered materials have rather weaker interlayer bonding than the intralayer bonding, therefore the exfoliation along the stacking direction enables the achievement of monolayer or few layers vdW materials with emerging novel physical properties and functionalities. The ferroelectricity in vdW materials recently attracts renewed interest for the potential use in high-density storage devices. With the thickness becoming thinner, the competition between the surface energy, depolarization field, and interfacial chemical bonds may give rise to the modification of ferroelectricity and crystalline structure, which has limited investigations. In this work, combining the piezoresponse force microscope scanning, contact resonance imaging, the existence of the intrinsic in-plane polarization in vdW ferroelectrics CuInP2 S6 single crystals is reported, whereas below a critical thickness between 90 and 100 nm, the in-plane polarization disappears. The Young's modulus also shows an abrupt stiffness at the critical thickness. Based on the density functional theory calculations, these behaviors are ascribed to a structural phase transition from monoclinic to trigonal structure, which is further verified by transmission electron microscope technique. These findings demonstrate the foundational importance of structural phase transition for enhancing the rich functionality and broad utility of vdW ferroelectrics.

Carbon nanoparticles derived from carbon soot as a matrix for SALDI-MS analysis.

Carbon nanoparticles (NPs) from the incomplete combustion of a candle were used as matrix for surface-assisted laser desorption/ionization mass spectrometry (SALDI-MS). The washed carbon soot NPs (WCS NPs, ~48 nm) exhibit higher laser desorption/ionization efficiency and less background compared with other common metal and carbon matrices. WCS NPs present good reproducibility and high sensitivity in analyzing a wide range of molecules in both positive and negative ionization mode in SALDI-MS. The detection limit of glucose is 1 pmol with WCS NPs as matrix. WCS NPs can be used to quantitatively determine urine glucose, visualize latent fingerprint and image it with SALDI-MS. The UV absorption of WCS NPs and MS spectra analyzed with WCS NPs matrix remain the same after 10 months storage, indicating the good stability of WCS NPs as matrix. Graphical abstractSchematic representation of carbon nanoparticles derived from carbon soot and its application as matrix in SALDI-MS.

Topological Phase Transition with Nanoscale Inhomogeneity in (Bi1- xIn x)2Se3.

Topological insulators are a class of band insulators with nontrivial topology, a result of band inversion due to the strong spin-orbit coupling. The transition between topological and normal insulator can be realized by tuning the spin-orbit coupling strength and has been observed experimentally. However, the impact of chemical disorders on the topological phase transition was not addressed in previous studies. Herein, we report a systematic scanning tunneling microscopy/spectroscopy and first-principles study of the topological phase transition in single crystals of In-doped Bi2Se3. Surprisingly, no band gap closure was observed across the transition. Furthermore, our spectroscopic-imaging results reveal that In defects are extremely effective "suppressors" of the band inversion, which leads to microscopic phase separation of topological-insulator-like and normal-insulator-like nano regions across the "transition". The observed topological electronic inhomogeneity demonstrates the significant impact of chemical disorders in topological materials, shedding new light on the fundamental understanding of topological phase transition.

Biodegradable, Hydrogen Peroxide, and Glutathione Dual Responsive Nanoparticles for Potential Programmable Paclitaxel Release.

Reactive oxygen species (ROS) and glutathione (GSH) dual responsive nanoparticulate drug delivery systems (nano-DDSs) hold great promise to improve the therapeutic efficacy and alleviate the side effects of chemo drugs in cancer theranosis. Herein, hydrogen peroxide (H2O2) and GSH dual responsive thioketal nanoparticle (TKN) was rationally designed for paclitaxel (PTX) delivery. Compared to other stimuli-sensitive nano-DDSs, this dual responsive DDS is not only sensitive to biologically relevant H2O2 and GSH for on-demand drug release but also biodegradable into biocompatible byproducts after fulfilling its delivering task. Considering the heterogeneous redox potential gradient, the PTX loaded TKNs (PTX-TKNs) might first respond to the extracellular ROS and then to the intracellular GSH, achieving a programmable release of PTX at the tumor site. The selective toxicity of PTX-TKNs to tumor cells with high levels of ROS and GSH was verified both in vitro and in vivo.

Improved motor control method with measurements of fiber optics gyro (FOG) for dual-axis rotational inertial navigation system (RINS).

Benefiting from frame structure, RINS can improve the navigation accuracy by modulating the inertial sensor errors with proper rotation scheme. In the traditional motor control method, the measurements of the photoelectric encoder are always adopted to drive inertial measurement unit (IMU) to rotate. However, when carrier conducts heading motion, the inertial sensor errors may no longer be zero-mean in navigation coordinate. Meanwhile, some high-speed carriers like aircraft need to roll a certain angle to balance the centrifugal force during the heading motion, which may result in non-negligible coupling errors, caused by the FOG installation errors and scale factor errors. Moreover, the error parameters of FOG are susceptible to the temperature and magnetic field, and the pre-calibration is a time-consuming process which is difficult to completely suppress the FOG-related errors. In this paper, an improved motor control method with the measurements of FOG is proposed to address these problems, with which the outer frame can insulate the carrier's roll motion and the inner frame can simultaneously achieve the rotary modulation on the basis of insulating the heading motion. The results of turntable experiments indicate that the navigation performance of dual-axis RINS has been significantly improved over the traditional method, which could still be maintained even with large FOG installation errors and scale factor errors, proving that the proposed method can relax the requirements for the accuracy of FOG-related errors.

Toward the Intrinsic Limit of the Topological Insulator Bi_{2}Se_{3}.

Combining high resolution scanning tunneling microscopy and first principles calculations, we identified the major native defects, in particular the Se vacancies and Se interstitial defects, that are responsible for the bulk conduction and nanoscale potential fluctuations in single crystals of archetypal topological insulator Bi_{2}Se_{3}. Here it is established that the defect concentrations in Bi_{2}Se_{3} are far above the thermodynamic limit, and that the growth kinetics dominate the observed defect concentrations. Furthermore, through careful control of the synthesis, our tunneling spectroscopy suggests that our best samples are approaching the intrinsic limit with the Fermi level inside the band gap without introducing extrinsic dopants.

Selective adsorption of arsenate and the reversible structure transformation of the mesoporous metal-organic framework MIL-100(Fe).

Here we describe a highly porous metal-organic framework MIL-100(Fe), which is initially used as an arsenate adsorbent in water. An appropriate mesoporous size allows AsO4(3-) to enter unrestrained and then be captured successfully, furthermore resulting in the damage of long-range order of uniform mesopores. Moreover, the porous framework could also make AsO4(3-) be reversibly desorbed without structural changes and the long-range order of mesopores be recovered again.

Direct visualization of magnetoelectric domains.

The coupling between the magnetic and electric dipoles in multiferroic and magnetoelectric materials holds promise for conceptually novel electronic devices. This calls for the development of local probes of the magnetoelectric response, which is strongly affected by defects in magnetic and ferroelectric ground states. For example, multiferroic hexagonal rare earth manganites exhibit a dense network of boundaries between six degenerate states of their crystal lattice, which are locked to both ferroelectric and magnetic domain walls. Here we present the application of a magnetoelectric force microscopy technique that combines magnetic force microscopy with in situ modulating high electric fields. This method allows us to image the magnetoelectric response of the domain patterns in hexagonal manganites directly. We find that this response changes sign at each structural domain wall, a result that is corroborated by symmetry analysis and phenomenological modelling, and provides compelling evidence for a lattice-mediated magnetoelectric coupling. The direct visualization of magnetoelectric domains at mesoscopic scales opens up explorations of emergent phenomena in multifunctional materials with multiple coupled orders.

Research on Parameter Estimation Methods for Alpha Stable Noise in a Laser Gyroscope's Random Error.

Alpha stable noise, determined by four parameters, has been found in the random error of a laser gyroscope. Accurate estimation of the four parameters is the key process for analyzing the properties of alpha stable noise. Three widely used estimation methods-quantile, empirical characteristic function (ECF) and logarithmic moment method-are analyzed in contrast with Monte Carlo simulation in this paper. The estimation accuracy and the application conditions of all methods, as well as the causes of poor estimation accuracy, are illustrated. Finally, the highest precision method, ECF, is applied to 27 groups of experimental data to estimate the parameters of alpha stable noise in a laser gyroscope's random error. The cumulative probability density curve of the experimental data fitted by an alpha stable distribution is better than that by a Gaussian distribution, which verifies the existence of alpha stable noise in a laser gyroscope's random error.

Duality of topological defects in hexagonal manganites.

We show that the spontaneous symmetry breaking in multiferroic hexagonal manganites can be chemically manipulated to yield two complementary ground states: the well-known ferroelectric P6(3)cm and an antipolar P3c phase. Both symmetry breakings yield topologically protected vortex defects, with the antipolar vortices dual to those of the ferroelectric. This duality stems from the existence of 12 possible angles of MnO5 tilting, and broad strain-free walls with low energy spontaneously emerge through an intermediate P3c1 state, providing a complete unified symmetry description.

Facile synthesis of porous Mn2O3 nanoplates and their electrochemical behavior as anode materials for lithium ion batteries.

Porous Mn2O3 nanoplates were prepared by a facile polyol solution method combined with a simple post-annealing process. The porous Mn2O3 nanoplates were characterized by XRD, field-emission SEM, high-resolution TEM, and N2 adsorption/desorption isotherm measurements. The formation process for the Mn2O3 nanoplates was proposed as a morphology-conserved transformation strategy. These porous nanoplates exhibited improved electrochemical performance with excellent cycling stability and good rate capability when applied as anode materials in lithium ion batteries.

AIMP2 restricts EV71 replication by recruiting SMURF2 to promote the degradation of 3D polymerase.

Hand, foot and mouth disease (HFMD), mainly caused by enterovirus 71 (EV71), have frequently occurred in the Asia-Pacific region, posing a significant threat to the health of infants and young children. Therefore, research on the infection mechanism and pathogenicity of enteroviruses is increasingly becoming important. The 3D polymerase, as the most critical RNA-dependent RNA polymerase (RdRp) for EV71 replication, is widely targeted to inhibit EV71 infection. In this study, we identified a novel host protein, AIMP2, capable of binding to 3D polymerase and inhibiting EV71 infection. Subsequent investigations revealed that AIMP2 recruits the E3 ligase SMURF2, which mediates the polyubiquitination and degradation of 3D polymerase. Furthermore, the antiviral effect of AIMP2 extended to the CVA16 and CVB1 serotypes. Our research uncovered the dynamic regulatory function of AIMP2 during EV71 infection, revealing a novel antiviral mechanism and providing new insights for the development of antienteroviral therapeutic strategies.

C1QTNF5 is a novel attachment factor that facilitates the entry of influenza A virus.

Influenza A virus (IAV) binds sialic acid receptors on the cell surface to enter the host cells, which is the key step in initiating infection, transmission and pathogenesis. Understanding the factors that contribute to the highly efficient entry of IAV into human cells will help elucidate the mechanism of viral entry and pathogenicity, and provide new targets for intervention. In the present study, we reported a novel membrane protein, C1QTNF5, which binds to the hemagglutinin protein of IAV and promotes IAV infection in vitro and in vivo. We found that the HA1 region of IAV hemagglutinin is critical for the interaction with C1QTNF5 protein, and C1QTNF5 interacts with hemagglutinin mainly through its N-terminus (1-103 aa). In addition, we further demonstrated that overexpression of C1QTNF5 promotes IAV entry, while blocking the interaction between C1QTNF5 and IAV hemagglutinin greatly inhibits viral entry. However, C1QTNF5 does not function as a receptor to mediate IAV infection in sialic acid-deficient CHO-Lec2 cells, but promotes IAV to attach to these cells, suggesting that C1QTNF5 is an important attachment factor for IAV. This work reveals C1QTNF5 as a novel IAV attachment factor and provides a new perspective for antiviral strategies.

Novel Acyl Thiourea-Based Hydrophobic Tagging Degraders Exert Potent Anti-Influenza Activity through Two Distinct Endonuclease Polymerase Acidic-Targeted Degradation Pathways.

The spread of the influenza virus has caused devastating pandemics and huge economic losses worldwide. Antiviral drugs with diverse action modes are urgently required to overcome the challenges of viral mutation and drug resistance, and targeted protein degradation strategies constitute excellent candidates for this purpose. Herein, the first degradation of the influenza virus polymerase acidic (PA) protein using small-molecule degraders developed by hydrophobic tagging (HyT) technology to effectively combat the influenza virus was reported. The SAR results revealed that compound 19b with Boc2-(L)-Lys demonstrated excellent inhibitory activity against A/WSN/33/H1N1 (EC50 = 0.015 µM) and amantadine-resistant strain (A/PR/8/H1N1), low cytotoxicity, high selectivity, substantial degradation ability, and good drug-like properties. Mechanistic studies demonstrated that the proteasome system and autophagic lysosome pathway were the potential drivers of these HyT degraders. Thus, this study provides a powerful tool for investigating the targeted degradation of influenza virus proteins and for antiviral drug development.