Search Results (748)

This paper presents a stability analysis of single-channel, slow-rolling, Semi-Automatic Command to Line of Sight (SACLOS) missiles using a comparison of the Routh–Hurwitz and the Frank–Wall stability criteria and a nonlinear analysis. Beginning with a six-degree-of-freedom (6-DOF) model in the Resal frame, a linearized model for the commanded motion is developed. This linearized model, which features complex coefficients due to the coupling of longitudinal channels in rolling missiles, is used to define the structural scheme of the commanded object and its flight quality parameters. The guidance kinematic relations, guidance device equations, and actuator relations, incorporating a switching function specific to slow-rolling, single-channel missiles, are also defined and linearized within the Resal frame to construct a comprehensive structural diagram of the SACLOS missile. From this, the characteristic polynomial with complex coefficients is derived and analyzed by comparing the Routh–Hurwitz and the Frank–Wall stability criteria. This analysis determines a stability domain for the guidance gain and establishes a minimum limit for the guidance time. The stability domain defined through the linear model is then validated using a nonlinear model in the body frame. Full article

The random thermal switching of domain walls (DWs) in perpendicularly magnetized anisotropy nanowires (PMA) poses a significant challenge for the reliability of spintronic storage devices. In this work, we study the thermal nucleation and dynamics of DWs in PMA nanowires using micromagnetic simulations. The focus is on the effect of device temperature, with attention to uniaxial anisotropy energy (K_u), saturation magnetization (M_s), and nanowire geometry. The results show that larger K_u or M_s reduces DW thermal switching, thereby enhancing DW thermal stability and increasing the DW nucleation temperature (T_n). A wider or thicker nanowire also lowers the probability of thermally induced DW creation, further improving stability. In addition, DW velocity rises with temperature, showing a thermally assisted motion. These results provide useful guidance for designing PMA-based memory devices with improved resistance to thermal fluctuations. Full article

The increasing integration of high-frequency power electronic converters in renewable energy-grid systems has escalated reliability concerns, necessitating FPGA-accelerated large-scale real-time electromagnetic transient (EMT) computation to prevent failures. However, most existing studies prioritize computational performance and struggle to achieve large-scale EMT computation. To enhance the computational scale, we propose a scalable hardware architecture comprising domain-specific components and data-centric processing element (PE) arrays. This architecture is further enhanced by a graph-based matrix mapping methodology and matrix-aware fixed-point quantization for hardware-efficient computation. We demonstrate our principles with FPGA implementations of large-scale multi-converter systems. The experimental results show that we set a new record of supporting 1200 switches with a computation latency of 373 ns and an accuracy of 99.83% on FPGA implementations. Compared to the state-of-the-art large-scale EMT computation on FPGAs, our design on U55C FPGA achieves an up-to 200.00× increase in the switch scale, without I/O resource limitations, and demonstrates up-to 71.70% reduction in computation error and 51.43% reduction in DSP consumption, respectively. Full article

This paper solves the stabilization problem of the continuous-time switched systems with partly unstabilizable subsystems subject to actuator saturation and data quantization. The static quantizer is designed by properly restraining the density of the finite partition. The relationship between an ellipse and a polyhedral is established and a suitable expression for the controller suffered by data quantization and actuator saturation is obtained. By defining the attraction domain and the invariant set based on the union or intersection of ellipses, we guarantee the decrement of the Lyapunov function in the optimal case if the state is within a given annular area. On this basis, if average dwell time and activation time of stabilizable subsystems meet some constraints, we derive that every trajectory whose initial state is within the given region will fall into a small ellipsoid and stay in a slightly larger ellipsoid. An illustrative example is given to verify the validity of the theoretical analysis. Full article

BACH1 (BTB And CNC Homology 1) and NRF2 (Nuclear Factor Erythroid 2-related Factor 2) are transcription factors that regulate antioxidant and iron metabolism genes by competing for binding to cis-regulatory Maf-binding elements (CsMBEs) as heterodimers with small Maf proteins (sMafs). To dissect the mechanisms underlying this competition, we developed a chimeric tethering system where the DNA-binding domains of BACH1 or NRF2 were covalently linked to sMafG via a flexible, cleavable linker. This design enables efficient heterodimer formation on DNA and circumvents kinetic barriers to partner exchange in the solution. The site-specific fluorescent labelling of proteins allowed for the tracking of complex compositions by electrophoretic mobility shift assays. Both BACH1/sMafG and NRF2/sMafG heterodimers bind CsMBEs with similar affinities. Notably, DNA binding by BACH1 was impaired in a C574-dependent, redox-sensitive manner and promoted the exchange of heterodimer partners. Competition assays demonstrated that BACH1 and NRF2 can displace each other from preformed DNA-bound complexes, with greater efficiency when presented as preassembled heterodimers with sMafG. These findings reveal a redox-sensitive mechanism for regulating transcriptional switches at CsMBEs and highlight how preformed heterodimers facilitate the rapid displacement at target promoters. Full article

Statistical factor models are widely applied across various domains of the financial industry, including risk management, portfolio selection, and statistical arbitrage strategies. However, conventional factor models often rely on unrealistic assumptions and fail to account for the fact that financial markets operate under multiple regimes. In this paper, we propose a regime-switching factor model estimated via a particle filtering algorithm, which is a Monte Carlo-based method well-suited for handling nonlinear and non-Gaussian systems. Our empirical results show that incorporating dynamic structure and a regime-switching mechanism significantly enhances the model’s ability to detect structure breaks and adapt to evolving market conditions. This leads to improved performance and reduced drawdowns in the equity statistical arbitrage strategies. Full article

Ship noise not only has an impact on crew comfort, but also causes damage to the marine environment. Longitudinal vibration of propulsion shaft system is one of the most important causes of ship noise, so in order to indirect control the vibration noise, the development of a propulsion shaft system vibration controller is an effective method. In this paper, a Kdamper with a magnetorheological damper (Kdamper-MRD) is proposed to control the longitudinal vibrations transmitted along the propulsion shaft system. The vibration characteristics of the propulsion shaft system are analyzed using the transfer matrix method and the optimal Kdamper-MRD design parameters for controlling the target modes are given. Specific structural design parameters are given as well as material selection. The magnetic field distribution and the magnitude of the output damping force of the MRD are obtained by the simulation method, and the negative stiffness characteristics of the disk spring are also discussed. An on–off current switching control strategy is proposed to further improve the vibration damping performance of the Kdamper-MRD. A comparison with the traditional DVA under simple harmonic excitation and random excitation proves that the Kdamper-MRD has better low-frequency vibration damping performance and is able to attenuate longitudinal vibration of the axle system in the whole frequency domain. Full article

Thiol isomerases are a family of enzymes that participate in oxidative protein folding. They contain highly reactive vicinal thiols in a CXXC motif within their catalytic domains to mediate thiol-disulfide switching as part of their reductase, oxidase, and isomerase activity. In addition, they participate in chaperone function by binding to partially folded or misfolded proteins and preventing aggregation, thereby facilitating correct protein folding. The CXXC motif is conducive to oxidative influence based on the sulfur nucleophilicity. Redox modification of the CXXC motif may influence the enzymatic function. In this review we briefly discuss the family of thiol isomerases as it relates to thrombotic disorders. We then discuss the chemical mechanisms of making and breaking disulfides by the enzymes. Enzymatic and chemical models of oxidizing the CXXC motif are proposed. Lastly, we highlight evidence that natural galloylated polyphenols can inhibit both the coronavirus main protease Mpro and thiol isomerases, supporting a therapeutic strategy for COVID-19-associated coagulopathy and thrombosis by targeting the CXXC motif with these anti-oxidative compounds. Full article

This paper proposes an enhanced Model Predictive Direct Speed Control (MPDSC) framework for Permanent Magnet Synchronous Motor (PMSM) drives, integrating duty ratio optimization and load torque disturbance compensation to significantly improve both transient and steady-state performance. Traditional finite-control-set MPC strategies, which apply a single voltage vector per sampling interval, often suffer from steady-state ripples, elevated total harmonic distortion (THD), and high computational complexity due to exhaustive switching evaluations. The proposed approach addresses these limitations through a novel dual-stage cost function structure: the first cost function optimizes dynamic response via predictive control of speed error, while the second adaptively minimizes torque ripple and harmonic distortion by adjusting the active–zero voltage vector duty ratio without the need for manual weight tuning. Robustness against time-varying disturbances is further enhanced by integrating a real-time load torque observer into the control loop. The scheme is validated through both MATLAB/Simulink R2020a simulations and real-time experimental testing on a dSPACE 1202 rapid control prototyping platform across small- and large-scale PMSM configurations. Experimental results confirm that the proposed controller achieves a transient speed deviation of just 0.004%, a steady-state ripple of 0.01 rpm, and torque ripple as low as 0.0124 Nm, with THD reduced to approximately 5.5%. The duty ratio-based predictive modulation ensures faster settling time, improved current quality, and greater immunity to load torque disturbances compared to recent duty-ratio MPC implementations. These findings highlight the proposed DR-MPDSC as a computationally efficient and experimentally validated solution for next-generation PMSM drive systems in automotive and industrial domains. Full article

To explore the advantages and limitations of employing square-wave modulated single-frequency signals in electric field radiated susceptibility testing, critical interference effect tests using both single-frequency continuous waves and square-wave modulated single-frequency radiation fields were conducted, respectively, at four susceptible frequencies (98, 262, 326, 404 MHz) of a linear voltage regulator and two susceptible frequencies (26, 36 MHz) of a switching-mode power supply. The variation law of critical interference field strength according to the modulation period was determined. The test results demonstrate that the output interruption in the tested power supplies was not only determined by the interference field strength and frequency but also significantly influenced by the repetition period of the interference signal. Square-wave modulated single-frequency interference provides superior characterization of the time-domain response characteristics of the equipment under testing when compared to conventional single-frequency continuous wave interference. However, RS103 only employs a modulated signal with a 1 ms repetition period, making it insufficient to fully characterize the actual susceptible characteristics of the tested equipment. Therefore, it requires supplementary evaluation through critical interference testing using single-frequency continuous waves. Full article

The resilience and sustainable development of modern power distribution systems faces escalating challenges due to increasing renewable integration and extreme events. Traditional single-system approaches often overlook the spatiotemporal coordination of cross-domain restoration resources. In this paper, we propose a multi-stage resilience enhancement method that employs transportation and hydrogen energy systems. This approach coordinates the pre-event preventive allocation and multi-stage collaborative scheduling of diverse restoration resources, including remote-controlled switches (RCSs), mobile hydrogen emergency resources (MHERs), and hydrogen production and refueling stations (HPRSs). The proposed framework supports cross-stage dynamic optimization scheduling, enabling the development of adaptive resource dispatch strategies tailored to the characteristics of different stages, including prevention, fault isolation, and service restoration. The model is applicable to complex scenarios involving dynamically changing network topologies and is formulated as a mixed-integer linear programming (MILP) problem. Case studies based on the IEEE 33-bus system show that the proposed method can restore a distribution system’s resilience to approximately 87% of its normal level following extreme events. Full article

Underwater wireless communication (UWC) is an emerging technology crucial for automating marine industries, such as offshore aquaculture and energy production, and military applications. It is a key part of the 6G vision of creating a hyperconnected world for extending connectivity to the underwater environment. Of the three main practicable UWC technologies (acoustic, optical, and radiofrequency), acoustic methods are best for far-reaching links, while optical is best for high-bandwidth communication. Recently, utilizing reconfigurable intelligent surfaces (RISs) has become a hot topic in terrestrial applications, underscoring significant benefits for extending coverage, providing connectivity to blind spots, wireless power transmission, and more. However, the potential for further research works in underwater RIS is vast. Here, for the first time, we conduct an extensive survey of state-of-the-art of RIS and metasurfaces with a focus on underwater applications. Within a holistic perspective, this survey systematically evaluates acoustic, optical, and hybrid RIS, showing that environment-aware channel switching and joint communication architectures could deliver holistic gains over single-domain RIS in the distance–bandwidth trade-off, congestion mitigation, security, and energy efficiency. Additional focus is placed on the current challenges from research and realization perspectives. We discuss recent advances and suggest design considerations for coupling hybrid RIS with optical energy and piezoelectric acoustic energy harvesting, which along with distributed relaying, could realize self-sustainable underwater networks that are highly reliable, long-range, and high throughput. The most impactful future directions seem to be in applying RIS for enhancing underwater links in inhomogeneous environments and overcoming time-varying effects, realizing RIS hardware suitable for the underwater conditions, and achieving simultaneous transmission and reflection (STAR-RIS), and, particularly, in optical links—integrating the latest developments in metasurfaces. Full article

9-cis-epoxycarotenoid dioxygenases (NCEDs), serving as the rate-limiting enzymes in abscisic acid (ABA) biosynthesis, play a pivotal role in regulating plant growth and development, as well as responses to abiotic stresses. Despite their agronomic importance, the molecular dialog between ABA signaling and vernalization, a cold-induced switch from vegetative to reproductive growth in wheat, remains poorly characterized, particularly regarding the TaNCED gene family members. Here, we systematically identified 13 TaNCED members in hexaploid wheat, followed by multi-omics characterization encompassing physicochemical properties, exon–intron architectures, conserved catalytic domains, protein motifs, and cis-acting elements. By analyzing transcriptome data from vernalization treatments, we profiled the expression patterns of TaNCED genes during vernalization. Notably, TaNCED5-6A, TaNCED5-6B, and TaNCED5-6D exhibited significant upregulation in vernalized leaves and tiller buds, while maintaining basal expression in the shoot apical meristem, the site of floral induction. This tissue-specific expression pattern implicates their specialized role in mediating vernalization responses via ABA biosynthesis. Collectively, our findings provide novel insights into the regulatory mechanisms of ABA-mediated vernalization in wheat and offer valuable targets for vernalization efficiency in cereal breeding programs. Full article

A class E inverter has presented wide application prospects in inductive wireless power transfer (WPT) systems due to its significant advantages such as high operation frequency, high power density, and low cost. However, its semiconductor power device is subjected to voltage stress several times higher than the input DC voltage, which inevitably increases the risk of overvoltage failure and limits the system power level. In this manuscript, an inductive WPT system with the pull–push class EF2 inverter is proposed to significantly decrease the voltage stress and ensure soft switching characteristic. The working principle and time-domain waveforms of the pull–push class EF2 inverter are analyzed. Moreover, the differential equations and mathematical model of the resonant parameters are investigated. Compared with the conventional class E inverter, the output power of the proposed inductive WPT system is doubled under the same input voltage. A 100 W system prototype is designed at the operating frequency of 6.78 MHz (according to the A4WP standard) and its experimental results demonstrate the effectiveness and feasibility of the analysis. Full article

RASSF4 is a key member of the Ras-associated domain family (RASSF) that exhibits dual functionality in tumorigenesis, playing critical yet context-dependent roles in various malignancies. Its expression is epigenetically regulated through promoter hypermethylation, histone modifications, and microRNAs including miR-155 and miR-196a-5p, which directly target its 3′ untranslated region. In most cancers, such as non-small cell lung cancer (NSCLC) and gastric adenocarcinoma (GAC), RASSF4 acts as a tumor suppressor by inhibiting the RAS/MAPK pathway while activating the Hippo signaling cascade, ultimately inducing cell cycle arrest and apoptosis. Conversely, in aRMS, RASSF4 is upregulated by the PAX3-FOXO1 fusion oncoprotein and promotes tumor growth through MST1 inhibition and subsequent YAP activation. This review systematically analyzes current evidence regarding RASSF4’s complex regulatory mechanisms and clinical significance. We propose targeted therapeutic strategies including epigenetic reactivation, gene intervention, and combination therapies. Furthermore, we identify RASSF4 as a promising diagnostic biomarker and therapeutic target based on integrated mechanistic and clinical evidence. Future research should focus on elucidating context-dependent regulatory switches, developing targeted delivery systems, and validating clinical utility through prospective trials. Full article