The high cooling rate needed for preparing the metallic glass (MG) makes the nonequilibrium nature of glass formation more prominent and requires a better quenching technique than ever before. Here, the cooling process is formulated analytically to reveal the determinants for cooling rate, and the crystallization time with consideration of phase diagram is calculated. Based on the reduced glass transition temperature, T rg , for measuring the glass-forming ability (GFA), a more reasonable Delta T rg is presented. Glass transition, especially in ever glass whose ground state is of glass, is discussed in terms of thermodynamics for phase transition. A fundamental law concerning the changing rate of entropy in a closed system is proposed to underlie the physics for glass formation. These results may help understand the glass formation principally and develop new and robust MGs technically.

This study presents a Two-Scenario Cascade Utilization (MSCU) model aimed at the secondary application of retired electric vehicle batteries to mitigate energy scarcity and curb environmental pollution. Utilizing the Newton-Raphson Backtracking Optimization (NRBO) algorithm, the research refines battery capacity allocation, optimizing economic outcomes across energy storage scenarios. Detailed cost, revenue, and policy subsidy analyses demonstrate that cascade utilization can extend battery service life by 7 years from an initial 80 % state of charge (SOC) and reduce energy storage system costs. With an initial investment of 10 million yuan, the system's annual net revenue is enhanced by 2.30 million yuan, reducing the payback period to 5 years from 9. The pivotal impact of unit capacity costs, at 1550 yuan/kW & sdot;h, and peak-to-off-peak electricity price differentials on economic feasibility is emphasized. For instance, a decrease in battery cost to 1500 yuan/kW & sdot;h results in a net revenue increase to 8.24 million yuan, with the payback period shrinking to 1.21 years. The NRBO algorithm, tested on benchmark functions, showed superior performance with an average best fitness of 9.98 and a standard deviation of 0.84, highlighting its effectiveness in global optimization. The study contributes to sustainable development by proposing a framework for retired battery reuse, offering valuable guidance for policymakers and energy industry stakeholders.

The prevalence of wide‐bandgap (WBG) semiconductors allows modern electronic devices to operate at much higher frequencies. However, development of soft magnetic materials with high‐frequency properties matching the WBG‐based devices remains challenging. Here, a promising nanocrystalline–amorphous composite alloy with a normal composition Fe 75.5 Co 0.5 Mo 0.5 Cu 1 Nb 1.5 Si 13 B 8 in atomic percent is reported, which is producible under industrial conditions, and which shows an exceptionally high permeability at high frequencies up to 36 000 at 100 kHz, an increase of 44% compared with commercial FeSiBCuNb nanocrystalline alloy (25 000 ± 2000 at 100 kHz), outperforming all existing nanocrystalline alloy systems and commercial soft magnetic materials. The alloy is obtained by a unique magnetic‐heterogeneous nanocrystallization mechanism in an iron‐based amorphous alloy, which is different from the traditional strategy of nanocrystallization by doping nonmagnetic elements (e.g., Cu and Nb). The induced magnetic inhomogeneity by adding Co atoms locally promotes the formation of highly ordered structures acting as the nuclei of nanocrystals, and Mo atoms agglomerate around the interfaces of the nanocrystals, inhibiting nanocrystal growth, resulting in an ultrafine nanocrystalline–amorphous dual‐phase structure in the alloy. The exceptional soft magnetic properties are shown to be closely related to the low magnetic anisotropy and the unique spin rotation mechanism under alternating magnetic fields.

Pulsed electric current sintering (PECS) was a rapid consolidation method to realize the accelerated densification process by the synergistic effects of thermal and non-thermal (electromigration) of pulsed electric current (PEC). However, due to the complexity of deconvolution of PEC and temperature and thus lack of quantitative depict of electromigration effect, the non-thermal effects of PEC were still not well understood, despite its proven significance. Here, we proposed an electromigration-related atomic diffusion De to explicitly clarify the non-thermal effects of PEC on mass transfer. Then, through introducing an in-situ electrically insulative Al2O3 thin-layer into the regular current-assisted sintering tooling, we can cutoff the PEC bypassing powder particles to investigate systematically the thermal and non-thermal effects of PEC on densification behaviors. Further, the modified model was validated by experimental data at with-current and without-current sintering modes. We demonstrated that an electromigration-related atomic diffusion De derived herein can be used to unravel quantitatively the contribution of electromigration to densification kinetics. Our work would be helpful to understand deeply the densification mechanism of PECS and elucidate the advantage of non-thermal effect of PEC on densification, which would be used to guide design and preparation of high-performance functional materials.

Development of metallic thin films with comprehensive properties fulfilling the needs of modern Micro/Nano Electro Mechanical Systems (M/NEMS) devices remains challenging. Here, a fully amorphous Ta90Co10 is screened out by combinatorial sputtering and atomic manufacturing technique, and the Ta90Co10 thin film metallic glass exhibits simultaneously a super-high crystallization temperature of 1325 K, a high hardness of 16.3 GPa, a high strength of 5000 MPa, and a large plastic strain exceeding 50%, outperforming all existing thin film materials. The excellent properties can be attributed to the atomic-scale structural heterogeneity induced by formation of different configurations in amorphous structure. The present work provides an approach to develop new M/NEMS-based thin film materials with outstanding comprehensive properties.

This paper presents a case study of the full development process from modelling and design to build, vehicle integration and testing of a 20 kW rated wireless charging system. The combined charging system (CCS) DC charging interface on the vehicle was used for vehicle charging and communication. The work motivation along with details of the system design, construction and vehicle integration are included in this paper. The main learning points are discussed and test results showing the final system in operation are presented.

Thin film metallic glasses (TFMGs) have attracted great attention due to their excellent functional properties and ease of fabrication as compared with bulk metallic glasses. Among them, TaW-based TFMGs have rarely been studied so far. Here, a novel Ta46.5W35Co18.5 TFMG was successfully developed using a magnetron co-sputtering system. The Ta46.5W35Co18.5 TFMG exhibits high hardness of 12.3 GPa, high elastic modulus of 159 GPa, pronounced plastic deformation behavior, and excellent corrosion resistance, i.e., low passive current density of 7.65 x 10(-6) A/cm(2) and high corrosion potential of 0.31 V, as well as good thermal stability with high onset crystallization temperature of 1100 K. In addition, the origin of these excellent properties was also investigated in detail by using X-ray diffraction and high-resolution transmission electron microscopy. It was found that, for the Ta46.5W35Co18.5 TFMG, its excellent corrosion resistance may be attributed to the amorphous structure, and the high hardness and good plastic deformation ability are caused by the unique atomic-scale structure with nanocrystals dispersed in the amorphous matrix. This work provides a useful guideline for developing TFMG system combined with excellent corrosion resistance, high hardness, and good thermal stability. (C) 2021 Elsevier B.V. All rights reserved.

Fe-based bulk metallic glasses (BMGs) usually exhibit brittle behavior and unconspicuous β-relaxation in their dynamic mechanical spectroscopy. We report a distinct β-relaxation behavior in FeNi-based BMGs with excellent plasticity. The origin of pronounced β-relaxation and plastic behaviors for the FeNi-based BMGs were investigated by synchrotron X-ray diffraction and nanoindentation tests in detail. It is found that the structural heterogeneity plays a key role in the dynamic of the FeNi-based BMGs, leading to large amount of loosely packed regions. The pronounced β-relaxation is also found to have a good correlation with the plasticity for the FeNi-based BMGs. This study might provide guidance for us to develop plastic BMGs from an atomic structural and glass dynamic perspective.

Metal and alloy nanoparticles synthesized by chemical reduction have attracted increasing attention due to their superior physical, chemical, and biological properties. However, most chemical synthesis processes rely on the use of harsh reducing agents and complicated chemical ingredients. Herein, we report a novel reduction-agent-free and surfactant (stabilizer)-free strategy to synthesize Cu, Ag, Au, Cu-Pt, Cu-Au, Cu-Au-Pt-Pd, and Au-Pt-Pd-Cu nanoparticles by ultrasound-assisted dealloying of Mg-based metallic glasses. The formation mechanism of the metal and alloy nanoparticles is revealed by a detailed investigation of sequential intermediate products. We demonstrate that the glass-liquid phase transition of the initially dealloying metallic glasses, together with the synergistic effect of dealloying and ultrasound-driven ligament-breakage of small enough nanoporous intermediates, play key roles in preparing the uniformly dispersed metal and alloy nanoparticles. This approach greatly simplifies the up-scaling synthesis of monometallic and bimetallic nanoparticles, and also provides a general strategy for synthesizing unprecedented multimetallic nanoparticles.

Nanoporous metals prepared by dealloying have attracted increasing attention due to their interesting size-dependent physical, chemical, and biological properties. However, facile fabrication of metallic ultrathin freestanding nanoporous films (UF-NPFs) by dealloying is still challenging. Herein, we report a novel strategy of facile preparation of flexible Cu, Cu3Ag, and CuAg UF-NPFs by dealloying thick Mg-Cu(Ag)-Gd metallic glass ribbons. During dealloying, the local reaction latent heat-induced glass transition of the precursor ribbons leads to the formation of a solid/liquid interface between the initially dealloyed nanoporous layer and the underlying supercooled liquid layer. Due to the bulging effect of in situ generated H2 on the solid/liquid interface, Cu, Cu3Ag, and CuAg UF-NPFs with thicknesses of ∼200 nm can self-peel off from the outer surface of the dealloying ribbons. Moreover, it was found that the surface-enhanced Raman scattering (SERS) detection limit of Rhodamine 6G (R6G) on the Cu and CuAg UF-NPF substrates are 10−6 M and 10−11 M, respectively, which are lower than most of the Cu and Cu-Ag substrates prepared by other methods. This work presents a reliable simple strategy to synthesize a variety of cost effective and flexible metallic UF-NPFs for functional applications.

A voltage optimizer (VO) to regulate overrated electricity supply voltages to optimized values with high reliability and efficiency has been developed based on a direct PWM ac-ac buck converter. A comprehensive control strategy is proposed for the ac-ac converter to address existing commutation problems and also to offer a fault handling capability against short circuits. A number of switching states are defined depending on the input voltage, whereby continuous and reliable current paths are maintained at all times especially around voltage zero-crossing points, and safe transitions between them are achieved as well. Based on a detailed power loss analysis, a hybrid scheme with silicon carbide (SiC) MOSFETs and silicon IGBTs is proposed which significantly improves the efficiency while minimizes the cost, and simultaneously enables the use of a high switching frequency, with the potential to reduce the volume of a VO. Results from simulation and experiment confirm that the proposed strategies give reliable operation of the VO with an efficiency higher than 99%.

A unique multiparameter sensor for distributed measurement of temperature and strain based on spontaneous Brillouin scattering in polyimide-coated optical fiber is proposed, which is an excellent candidate for the cross-sensitivity problem in conventional Brillouin sensing network. In the experimental section, the discrimination of strain and temperature is successfully demonstrated by analysing the unequal sensing coefficients of the Brillouin frequency shifts generated by different acoustic modes. The Brillouin frequency shifts of the main two peaks are successfully measured to discriminate the strain and temperature with an accuracy 19.68 με and 1.02°C in 2.5 km sensing range. The proposed distributed Brillouin optical fiber sensor allows simultaneous measurement of temperature and strain, thus opening a door for practical application such as oil explorations.

A multi-parameter sensor for distributed measurement of temperature and strain based on Brillouin scattering in dispersion-shifted fiber is proposed, which is an excellent candidate for the cross effects in traditional Brillouin sensing system. In experiment, a temperature accuracy of 2 ℃, a strain accuracy of 60 με are achieved simultaneously.

The structural order in metallic supercooled liquids and glasses is a long-standing issue. Unlike the medium-range order (MRO) which involves at least hundreds of atoms, short-range order (SRO) only concerns the central atom and its neighbors, which can be described more easily. Here, we use the molecular dynamics simulation to investigate the SRO in supercooled liquids and glasses of two pure metals Ta and Ni respectively with the body-centered cubic (BCC) and the face-centered cubic (FCC) crystalline lattice and two binary alloys Cu50Zr50 and Ni50Al50 both with a B2 crystalline phase. To compare, a ternary alloy of Cu47.5Zr47.5Al5 is also investigated. Hexagonal closed-packed (HCP) and icosahedron (ICO) clusters are found to dominate the SRO in both supercooled liquids and glasses. As expected, the glass is found more structurally ordered than the supercooled liquid. The glass transition is found to be linked to the kink of the temperature dependence of SRO. The binary system, as the relatively good glass-former, is less structurally ordered than the monatomic system as a poor glass-former, but it is more structurally ordered than the ternary one. These findings have profound implications for understanding the glass transition and designing new metallic glasses.

In this paper, a reliable control strategy is proposed for the direct pulse-width-modulation (PWM) ac-ac buck converter, to address the commutation problems and also to offer a handling capability against short circuit faults. A number of states are defined for the switching of the ac-ac converter depending on the sensed input voltage, whereby safe and continuous current paths are maintained at all times including voltage zero-crossing points. Moreover, fault handing switching states are able to protect the converter against short circuit currents. Safe transitions between different states are achieved as well. The realization of the control method is introduced and analyzed in detail. Measured results from experiments confirm that the proposed strategy manages to provide a safe and smooth operation for the ac-ac buck converter even under short circuit faults.

A novel phase-locked loop (PLL) with simple structure is proposed in the present work for three-phase power converters under adverse grid conditions. Based on a synchronous rotating frame PLL (SRF-PLL), multi-resonant harmonic compensators with the ability of accommodating frequency deviations are employed in the feedback path of a pre-filter. As a result, the negative-sequence component and harmonic distortions of grid voltage can be attenuated. Different from existing methods, only classical regulators are used, avoiding complicated networks for the decoupling of unbalance and harmonics and thus greatly simplifying the control algorithm. The proposed method is analysed and designed in both the continuous s-domain and discrete z-domain, whereby stable, fast, accurate, and robust responses are achieved. Simulation results have been obtained to show the improved performance of the proposed PLL compared with two widely used methods.

Every new discovery in the history of biology, such as the essence of life, the origin of life, the discovery of cells, the establishment of cytology, the cell biology at the molecular level, etc., the biologist has left brilliant track in the journey of scientific innovation. The home climbs the glorious footprint of the Science Foothills. Nowadays, to cultivate cross-century competitive high-quality talents, we must advocate the spirit of not afraid of difficulties, fore ahead, and be brave to explore; we must conscientiously study and master the basic concepts, theories and methods of biology, with history and philosophy. Trace back to these concepts, theories and methods. In this way, we will improve our ability of innovation, continue to have new and more discoveries in science.

Objective To investigate the clinical application of repairing the large-area skin defect of legs with medial-lower-leg-flap with a healthy limb cross-leg bridging thoracic umbilical flap. Methods 16 cases with a large area of soft tissue defects caused by severe trauma were included in this study. The vascular pedicles of free thoracic umbilical flap were anastomosed with the opposite posterior tibial artery and vein, and the pedicle skin tubes were made and amputated 4 weeks after surgery.Observation of postoperative flap include survival situation, shape, color, elastic, scar contracture, and dysfunction. Results 16 cases of postoperative all flaps survived.In 1 case pain occurred 10 hours after the operation and led to arterial crisis, which was relieved with analgesia.There were no vascular crisis in other 15 eases. Followed up for 2-24 months, all the flaps survived with good color, elasticity and sensory recovery. There was no apparent stiffness in double knee and ankle joint. Conclusions For the injured limbs impossible to be repaired with local vascular pedicle, routine local transfer of skin flap or cross leg skin flap, the bridge cross anastomosis of free flap graft may be an ideal surgical treatment. Key words: Medial lower leg flap; Thoracic umbilical flap; Bridge cross anastomosis; Repair

In this paper, a dynamic power system model is proposed, with the aim to study the interconnection between energy storage (ES) systems such as compressed air energy storage (CAES) and power networks. All features in a power system, e.g., frequency, voltage, current, active and reactive powers, are considered in the model. Furthermore, the dynamic model enable an easy integration of ES models, making it a useful software tool to study the feasibility of ES in providing ancillary services to power networks. Case studies with the integration of CAES have been carried out, which reveal that the CAES has the potential to strength and optimize the operation of power systems, especially in terms of load balance, and frequency and voltage regulation.

To ensure the stability and reliability of the power network operation, a number of Grid Codes have been used to specify the technical boundary requirements for different countries and areas. With the fast propagation of the usage of Electrical Energy Storage (EES), it is quite important to study how the EES technology with its development can help the Grid Code realization. The paper provides a comprehensive study of Great Britain (GB) Grid Code mainly on its voltage and frequency relevant specifications, with a comparison of other countries' grid operation regulations. The different types of EES technologies with their technical characteristics in relation to meeting Grid Codes have been analysed. From the study, apart from direct grid-connection to provide grid services on meeting Grid Codes, EES devices with different technologies can be used as auxiliary units in fossil-fuelled power plants and renewable generation to support the whole systems' operation. The paper also evaluates the potentials of different types of EES technologies for implementing the relevant applications based on the Grid Codes. Some recommendations are given at the end, for the EES technology development to help the Grid Code realization and to support the relevant applications.