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The 1.2 kV vertical GaN fin-channel junction field-effect transistor (JFET) is an emerging industrial device with low specific on-resistance (RON), normally-off operation, and avalanche capability. This article reports the first comprehensive evaluation of 1.2 kV, 75 mΩ gallium nitride (GaN) JFET in converter applications. The RC-interface gate driver is optimized through the double-pulse test (DPT). To quantify the device's conduction loss, an in-situ measurement of dynamic RON is performed in a continuous DPT at steady-state. The vertical GaN JFET shows no dynamic RON issue. Subsequently, a GaN JFET-based half bridge is evaluated in a zero-voltage-switching (ZVS) buck converter under various frequencies, duty cycles, and load conditions. For comparison, similarly-rated SiC mosfet and Si IGBT are tested in the same converter. Benefitting from the lowest output capacitance and output charge, the GaN JFET requires a short deadtime and enables MHz operation in the 800-V ZVS buck converter. The GaN converter achieves a maximum efficiency of 97.7% at 1 MHz and 98.0% at 500 kHz and shows a general advantage in frequency and efficiency compared to the same converters based on SiC mosfet and Si IGBT. In addition, under the operational driver condition, the 1.2 kV GaN JFET shows a long short-circuit withstanding time of over 40 μs at 800 V. These results provide key reference for the application of 1.2 kV GaN JFETs and suggest that a GaN device with proper designs can achieve excellent stability and robustness.

This article quantitatively investigates the design considerations for a planar Rogowski coil. Within one printed circuit board (PCB), the Rogowski coil is placed between the overlapping dc-bus traces, the dc-link capacitor, and the half-bridge. This integration allows for measuring both dc-bus currents with one Rogowski coil, hence enabling the Silicon Carbide (SiC) mosfet switch transient current measurement of both half-bridge mosfets with one coil. A parametric mutual inductance equation and the Rogowski coil transfer function are proposed to simplify the design process of a planar Rogowski coil. Design considerations are evaluated. In additionally, the induced measurement error due to current crowding within the dc bus is investigated, and the impact of Rogowski coil windings exceeding the dc-bus trace width as a measure to reduce the mutual inductance error is explored and experimentally validated. A $\mathbf {\text{106}\;mm^{2}}$ small planar Rogowski coil current sensor with a maximum bandwidth of $\mathbf {\text{185}\;MHz}$ is built. The prototype is evaluated for its parasitic parameters. Its current measurement performance is compared to that of a commercial Rogowski coil. Measurement results compare well between the planar Rogowski coil and the commercial Rogowski coil. In addition, measurements show that the mutual inductance of the proposed Rogowski coil is insusceptible to current crowding within the dc bus.

Compared with line-commutated converters (LCC) technology, voltage-source converters (VSCs), exemplified by modular multilevel converters (MMCs) have emerged as a superior alternative for HVdc applications, offering enhanced controllability, functionality, and modular design. However, VSC-MMC has relatively higher losses and energy storage requirements than LCC. Addressing these intrinsic drawbacks of VSC-MMCs, there has been a recent demand for converters that combine ultralow conduction losses and high power density from thyristor-based valves in LCC with VSC-MMCs' modularity and controllability. This article presents the architecture and operational strategy of one such converter: Thyristor-embedded hybrid MMC (SCR-HMMC). SCR-HMMC distinguishes itself by utilizing fewer switches, reducing arm energy storage requirements, and achieving lower losses compared with other state-of-the-art solutions. The bidirectional converter is adept at managing high-ac/low-dc and low-ac/high-dc voltage conversions while also boasting black-start functionality, modular design, and scalability. Its modularity and scalability combined with reduced expenses, losses, and size render SCR-HMMC a viable proposition for both high-voltage and medium-voltage (MV) applications. A 20-kW MV SCR-HMMC prototype has been fabricated for the laboratory setting, demonstrating successful operation in both inverter and rectifier modes, marking one of the first such in-depth practical demonstrations of a thyristor-embedded bidirectional multilevel VSC.

• This work introduces an innovative approach of doping with high entropy alloy (HEA) powder to fabricate melt-grown ternary oxide ceramic composites with complex turbine, conical, and cylindrical shapes, making a significant breakthrough in the field of laser powder bed fusion technology for melt-grown eutectic ceramics. • The directly solidified ceramic composites exhibit a smooth surface with a surface roughness of approximately 1.08 µm and a diameter of about 70 mm. They display ultra-fine eutectic microstructure with a eutectic spacing of about 61.4 nm. This represents the largest solidified eutectic ceramic composite with complex structure and ultra-fine microstructure by LPBF in one-step to date. • Through melt pool dynamics analysis, the dynamic behavior of doped particles in the molten pool and their mechanism of influence on the eutectic ceramic microstructure are revealed. As a 3D printing method, laser powder bed fusion (LPBF) technology has been extensively proven to offer significant advantages in fabricating complex structured specimens, achieving ultra-fine microstructures, and enhancing performances. In the domain of manufacturing melt-grown oxide ceramics, it encounters substantial challenges in suppressing crack defects during the rapid solidification process. The strategic integration of high entropy alloys (HEA), leveraging the significant ductility and toughness into ceramic powders represents a major innovation in overcoming the obstacles. The ingenious doping of HEA particles preserves the eutectic microstructures of the Al 2 O 3 /GdAlO 3 (GAP)/ZrO 2 ceramic composite. The high damage tolerance of the HEA alloy under high strain rates enables the absorption of crack energy and alleviation of internal stresses during LPBF, effectively reducing crack initiation and growth. Due to increased curvature forces and intense Marangoni convection at the top of the molt pool, particle collision intensifies, leading to the tendency of HEA particles to agglomerate at the upper part of the molt pool. However, this phenomenon can be effectively alleviated in the remelting process of subsequent layer deposition. Furthermore, a portion of the HEA particles partially dissolves and sinks into the molten pool, acting as heterogeneous nucleation particles, inducing the formation of equiaxed eutectic and leading primary phase nucleation. Some HEA particles diffuse into the lamellar ternary eutectic structures, further promoting the refinement of eutectic microstructures due to increased undercooling. The innovative doping of HEA particles has effectively facilitated the fabrication of turbine-structured, conical, and cylindrical ternary eutectic ceramic composite specimens with diameters of about 70 mm, demonstrating significant developmental potential in the field of ceramic composite manufacturing. [Display omitted] [ABSTRACT FROM AUTHOR]

There is a resurgence of research interest in inherently chiral calixarenes and heteracalixaromatics. However, the examples of macrocyclic ring-expanded homocalixarenes and heterocalixaromatics of inherent chirality are not known. Here we report an efficient method to construct inherently chiral N2,O2-linked homo-heteracalixaromatics from reductive amination reactions between bis-aldehydes and aliphatic diamines. Examples of post-macrocyclization derivatization were also demonstrated. Enantiomers were obtained from resolution and did not undergo racemization at an elevated temperature. This study provides a new strategy to design novel and functional inherently chiral macrocycles that have potential applications in supramolecular chemistry.

(±)-Salvicatone A (1), a C27-meroterpenoid featuring a unique 6/6/6/6/6-pentacyclic carbon skeleton with a 7,8,8a,9,10,10a-hexahydropyren-1 (6H)-one motif, was isolated from the roots and rhizomes of Salvia castaneaDiels f. tomentosaStib. Its structure was characterized by comprehensive spectroscopic analyses along with computer-assisted structure elucidation, including ACD/structure elucidator and quantum chemical calculations with 1H/13C NMR and electronic circular dichroism. Biogenetically, compound 1was constructed from decarboxylation following [4 + 2] Diels–Alder cycloaddition reaction between caffeic acid and miltirone analogue. Bioassays showed that (−)-1and (+)-1inhibited nitric oxide production in lipopolysaccharide-induced RAW264.7 macrophage cells with an IC50value of 6.48 ± 1.25 and 15.76 ± 5.55 μM, respectively. The structure-based virtual screening based on the pharmacophores in ePharmaLib, as well as the molecular docking and molecular dynamics simulations study, implied that (−)-1and (+)-1may potentially bind to retinoic acid receptor-related orphan receptor C to exert anti-inflammatory activities.

• The VPP 3D printed alumina ceramic cores with near zero shrinkage in the X direction has been realized for the first time. • A novel approach of atmosphere controlled in-situ oxidation of aluminum powder has been invented to improve the properties of ceramic cores. • A significant tenfold increase in the pore size of ceramic cores is conducive to improved solubility. • Formation of new powder consolidations during the sintering process. Vat photopolymerization (VPP) 3D printing technology has broken through mold limitations and shown great potential to manufacture complex-structured ceramic cores for turbine blades. However, improving dimensional accuracy is difficult for the VPP 3D printed parts due to the high contraction deformation. Reducing shrinkage is a key challenge for developing 3D-printed ceramic cores. In this study, 3D-printed alumina ceramic cores with near-zero shrinkage in the X direction were achieved for the first time using a novel approach that was called atmosphere-controlled in-situ oxidation of aluminum powder. The in-situ oxidation reaction of the aluminum powder was creatively tuned by changing the atmosphere transition temperature from argon to air. Then, the microstructure and properties of the ceramic core could be controlled by the liquid-phase sintering with the participation of atmosphere-protected molten aluminum. As a result, the pore size of the ceramic cores was significantly increased by almost ten times, but the bonding strength of the grains was also increased. In addition, the powder consolidation generated by the action of molten aluminum was considered to be an important reason for reducing the linear shrinkage of ceramic cores. Under the optimized parameters, the linear shrinkage of the ceramic cores was as low as 0.3% in the X direction. The high apparent porosity (45.02%) and flexural strength (72.7 MPa) of the alumina ceramic cores were realized at the same time. The in-situ control of sintering by changing the atmosphere will be a creative method for regulating the properties of ceramic materials. [Display omitted] [ABSTRACT FROM AUTHOR]

The triple-active-bridge (TAB) converter is a representative topology that seamlessly integrates dc sources and loads with galvanic isolation. Especially, there is a growing demand for an asymmetric TAB converter that provides distinct nominal powers at three ports, particularly in electric vehicles and power distribution systems. From the perspective of converter design, the leakage inductance is significant because it is related to zero-voltage switching (ZVS) of switches, and finally affects the power efficiency. Previous articles did not consider the asymmetric TAB converter and a clear guideline of designing leakage inductance for it has not been presented. In this situation, this article proposes a new method for determining leakage inductance for the asymmetric TAB converter. By using the proposed method, the ZVS regions in all power flow conditions are extended up to 62% more than those of the conventional method. Consequently, switching losses under light-load conditions are significantly reduced, enabling the converter to attain high power efficiency in a wide range of power conditions. The unified expression of asymmetric leakage inductance is addressed through the delta equivalent model of the TAB converter, and the comprehensive analysis of ZVS is discussed. The effect of the ZVS region extension with the proposed method is verified by comparing the ZVS regions between the conventional and proposed configurations. Through the simulation model of high-power scale, switch losses are estimated in various power flow conditions, validating the feasibility of the proposed method in practical industrial applications. The performance of the proposed method is finally demonstrated through a 3 kW reduced-scale TAB converter.

Infrared invisibility has continued to develop in recent decades, triggered by novel physics, advanced fabrication technology and raw materials. However, the quick response of infrared stealth during transmedia (water–air/water–land) movement, which is important in practical scenarios, has not been investigated. Here, we employ the random thermal effect of the interaction between laser and matter to construct a bionic flexible thin-film superhydrophobic infrared invisibility cloak. The average emissivity of invisibility cloak is 0.224 over 8–14 ${{\mu }}\text{m}$, and specular reflectivity at the incident angle of 10 degree is 1.1% over 2.5–16 ${{\mu }}\text{m}$. These characteristics indicate the integrated stealth functionality against active (laser) and passive (thermal) detection, respectively. The contact angle between the cloak and water is 154°, which also indicates its unique cross-media response capability. We also show that the developed infrared stealth cloak is robust to practical (nonideal) manufacturing conditions. Our design strategy expands the concept of infrared stealth to cross-media applications.

Vat photopolymerization (VPP) is a high potential and efficient method for fabricating advanced ceramics. However, the selection of printing strategy importantly determines the geometrical accuracy and mechanical strength of ceramic parts prepared by VPP. In this study, the effects of the curing depth (Cd) to layer thickness (Lt) ratio and Lton forming accuracy, microstructures, mechanical properties, surface roughness of biphasic calcium phosphate (BCP) bioceramic green bodies and sintered bodies were investigated. When the Cd/Ltratio was smaller than 4.0, and the Ltwas not over 50 μm, the green bodies presented high forming accuracy (the dimension errors ˂ 3.50 %). Inappropriate Cd/Ltand Ltcaused lots of defects including different types of cracks and delamination on green bodies and sintered bodies, and impaired their mechanical strength. The optimal Cd/Ltratio and Ltwere obtained to be 4.0 and 50 μm, in which parameters there were few cracks and delamination on the sintered BCP bioceramics. The flexural strength and the fracture toughness of sintered BCP increased when the Cd/Ltratio increased from 3.0 to 4.0. However, the flexural strength and the fracture toughness decreased when the Cd/Ltratio further increased to 5.0. The flexural strength of sintered BCP increased at first and then decreased when the Ltincreased from 25 μm to 50 μm, and the fracture toughness and hardness of BCP decreased continually. The flexural strength of sintered BCP showed a maximum value of 113.21 MPa, and the maximum fracture toughness was 0.71 MPa∙m1/2. The elastic modulus and hardness of sintered BCP also reached 24.16 GPa and 3.04 GPa, respectively. The printing surface roughness of BCP bioceramics decreased when the Cd/Ltratio or Ltincreased. The lateral surface roughness decreased with the increase of Cd/Ltratio, and increased with the increase of Lt. This new result provides a clear printing strategy for fabricating ceramics with high geometrical accuracy and mechanical properties by VPP technique.

• A scanning speed high enough (700 μm/s) caused microstructure coarsening due to the high viscosity and low atom diffusion rate of the melt. • At the final scanning position, the much faster heat dissipation resulted in microstructure refining accompanied by two-phase instability. • The solidified microstructure from bottom to top of the molten pool is different due to the change in heat dissipation and composition. • During LSZM, the secondary heating of the melting pool on the solidified eutectic zone in the molten pool formed arc-shaped coarse eutectic bands. • Both single-phase instability and two-phase instability damage the mechanical properties. Microstructure evolution and solidification behaviour of ZrB 2 -SiC composite ceramics fabricated by laser surface zone-melting were investigated. Microstructure coarsening at high scanning speed and microstructure refining after turning off the laser was observed due to the changes in the solidification rate. The solidification behaviour from bottom to top of the molten pool was studied, where there are some coarsen eutectic bands caused by the secondary heating of the melting pool on the solidified eutectic zone in the molten pool. The deviation of melt composition from the eutectic ratio due to the volatilization of SiC can form a coarse primary ZrB 2 phase among fine eutectic structure (single-phase instability), and the constitutional supercooling due to the accumulation of impurity elements can form coarse eutectic dendrites among fine eutectic structure (two-phase instability). Both single-phase instability and two-phase instability are adverse to the mechanical properties, which should be prevented by adjusting the composition of raw materials and the solidification process. [Display omitted] [ABSTRACT FROM AUTHOR]

High-power and high-density dc transformers (DCXs) are critical components in data center power supplies, energy storage systems, medium-voltage solid-state transformers, and transportation electrification. The challenges associated with designing high-power and high-frequency transformers are considerable. The electronic-embedded transformer (EET) concept, proposed in Cao et al. (2023), is a response to these challenges, integrating semiconductor electronics into the transformer windings. In light of this concept, this article presents two significant modifications. First, it replaces the complete full bridge with a low-voltage bidirectional ac switch. Second, it introduces a resonant commutation (RC) to realize a quasi-trapezoidal transformer current with a smaller rms value. Compared to the triangular current produced by the original EET-DCX in Cao et al. (2023), the rms current can be decreased by 15%. In addition to streamlining the circuit, the proposed RC EET-DCX retains all the advantages of the original EET-DCX, including simple open-loop control and natural current sharing. By incorporating only one embedded bidirectional ac switch, the impedance of the high-frequency transformer leakage inductance is fully neutralized. As a result, the rated power of the proposed RC EET-DCX can be readily scaled up through transformer-level parallelism. Furthermore, the RC EET-DCX maintains the benefits of typical LLC/CLLC-DCX, including load-independent voltage gain, full load range zero voltage switching, and low circulating current. To verify aforementioned benefits, a 12-kW RC EET-DCX with four planar RC EET units was built and tested.

With an integrated full bridge, the concept of an electronic-embedded transformer (EET) offers a solution of high-frequency, high-power fixed-gain isolated dc–dc conversion, known as a dc transformer (DCX), through the parallel operation of EET units with natural current sharing [1]. Besides, the trapezoidal current modulation can further reduce the root-mean-square (rms) current through the transformer [2]. However, this modulation will increase the voltage stress on the integrated full bridge, especially when the leakage inductance is large and variable, such as in the wireless charging application. To address this tradeoff between rms current and voltage stress, this article proposed the concept of a hybrid resonant-type EET-DCX with series resonant capacitor. Following this concept, two specific topologies named hybrid EET-DCX and hybrid resonant commutation (RC) EET-DCX were proposed. The main difference between these two topologies is the former adopted a full bridge and the latter utilized only one bidirectional ac switch. In hybrid RC EET-DCX, a resonant current commutation scheme was developed. Among these two topologies, since the leakage inductance impedance can be mainly canceled by the passive capacitor, the full bridge or ac switch only needs to handle the remaining part of the impedance. And thus, the device voltage stress on active components can be dramatically decreased. In addition, these two proposed topologies can both retain all the advantages of previous EET-DCX designs, including natural current sharing, load-independent voltage gain, simple open-loop operation, and full-load range zero-voltage switching. Finally, two 12-kW prototypes were built to verify the analysis and performance.

Antimicrobial peptides (AMPs) in insects are short peptides that play an important role in their innate defense system. The production of AMPs is typically induced by an infection of pathogenic microorganisms, but cold stress may also cause upregulation of insect AMP genes. However, little is known about the functions of AMPs in cold stress situations and the recovery afterwards. As most important results, in this project with Lasioderma serricorne that can tolerate long storage under cold conditions, we identified and investigated four AMP genes (LsAtt1, LsAtt3, LsCec and LsDef-like). We confirmed their anti-bactericide activity in in vitro assays and in RNAi assays. The cross treatments with cold stress showed that LsDef-like was upregulated under cold stress and its silencing caused a loss of survival. In contrast, the expression of the other three AMPs did not change, and their silencing prolonged the recovery time. We believe that our cross treatments, revealing an association between immune activation and cold stress with AMPs, will increase our basic understanding of the immune system and the “cross-talk” with cold resistance.

The overuse of antibiotics in animal farming and aquaculture has led to multidrug-resistant methicillin-sensitive Staphylococcus aureus(MR-MSSA) becoming a common pathogen in foodborne diseases. Sophora flavescensAit. serves as a traditional plant antibacterial agent and functional food ingredient. A total of 30 compounds (1–30) were isolated from the root bark of S. flavescens, consisting of 20 new compounds (1–20). In the biological activity assay, compound 1demonstrated a remarkable inhibitory effect on MR-MSSA, with an MIC of 2 μg/mL. Furthermore, 1was found to rapidly eliminate bacteria, inhibit biofilm growth, and exhibit exceptionally low cytotoxicity. Mechanistic studies have revealed that 1possesses an enhanced membrane-targeting ability, binding to the bacterial cell membrane components phosphatidylglycerol (PG), phosphatidylethanolamine (PE), and cardiolipin (CL). This disruption of bacterial cell membrane integrity increases intracellular reactive oxygen species, protein and DNA leakage, reduced bacterial metabolism, and ultimately bacterial death. In summary, these findings suggest that compound 1holds promise as a lead compound against MR-MSSA.

The properties and elevated temperature wear mechanism of pure copper and in situ TiC/Cu matrix composites fabricated via combustion synthesis assisted with hot press were investigated. Brinell hardness, compression properties and electrical conductivity were studied. It was found that of the Brinell hardness, yield strength and compressive strength of the composites is higher than sintered pure copper, however, the electrical conductivity and fracture strain of the composites are lower. Dry sliding friction and wear tests showed that the worn surface transformed from furrow to spalling pit and the wear rate increases with the increasing temperature and applied load, the wear failure changes gradually from surface plastic deformation, plough wear and oxidation wear to abrasive wear and fatigue spalling wear.

This cross‐sectional study aimed to determine the epidemiology of olfactory and gustatory dysfunctions related to COVID‐19 in China. This study was conducted by 45 tertiary Grade‐A hospitals in China. Online and offline questionnaire data were obtained from patients infected with COVID‐19 between December 28, 2022, and February 21, 2023. The collected information included basic demographics, medical history, smoking and drinking history, vaccination history, changes in olfactory and gustatory functions before and after infection, and other postinfection symptoms, as well as the duration and improvement status of olfactory and gustatory disorders. Complete questionnaires were obtained from 35,566 subjects. The overall incidence of olfactory and taste dysfunction was 67.75%. Being female or being a cigarette smoker increased the likelihood of developing olfactory and taste dysfunction. Having received four doses of the vaccine or having good oral health or being a alcohol drinker decreased the risk of such dysfunction. Before infection, the average olfactory and taste VAS scores were 8.41 and 8.51, respectively; after infection, they decreased to 3.69 and 4.29 and recovered to 5.83 and 6.55 by the time of the survey. The median duration of dysosmia and dysgeusia was 15 and 12 days, respectively, with 0.5% of patients having symptoms lasting for more than 28 days. The overall self‐reported improvement rate was 59.16%. Recovery was higher in males, never smokers, those who received two or three vaccine doses, and those that had never experienced dental health issues, or chronic accompanying symptoms. The incidence of dysosmia and dysgeusia following infection with the SARS‐CoV‐2 virus is high in China. Incidence and prognosis are influenced by several factors, including sex, SARS‐CoV‐2 vaccination, history of head‐facial trauma, nasal and oral health status, smoking and drinking history, and the persistence of accompanying symptoms.

Emerging evidence suggests that the gut microbiota is closely related to psychiatric disorders. However, little is known about the role of the gut microbiota in the development of obsessive-compulsive disorder (OCD). Here, to investigate the contribution of gut microbiota to the pathogenesis of OCD, we transplanted fecal microbiota from first-episode, drug-naive OCD patients or demographically matched healthy individuals into antibiotic-treated specific pathogen-free (SPF) mice and showed that colonization with OCD microbiota is sufficient to induce core behavioral deficits, including abnormal anxiety-like and compulsive-like behaviors. The fecal microbiota was analyzed using 16 S rRNA full-length sequencing, and the results demonstrated a clear separation of the fecal microbiota of mice colonized with OCD and control microbiota. Notably, microbiota from OCD-colonized mice resulted in injured neuronal morphology and function in the mPFC, with inflammation in the mPFC and colon. Unbiased metabolomic analyses of the serum and mPFC region revealed the accumulation of succinic acid (SA) in OCD-colonized mice. SA impeded neuronal activity and induced an inflammatory response in both the colon and mPFC, impacting intestinal permeability and brain function, which act as vital signal mediators in gut microbiota–brain–immune crosstalk. Manipulations of dimethyl malonate (DM) have been reported to exert neuroprotective effects by suppressing the oxidation of accumulated succinic acid, attenuating the downstream inflammatory response and neuronal damage, and can help to partly improve abnormal behavior and reduce neuroinflammation and intestinal inflammation in OCD-colonized mice. We propose that the gut microbiota likely regulates brain function and behaviors in mice via succinic acid signaling, which contributes to the pathophysiology of OCD through gut-brain crosstalk and may provide new insights into the treatment of this disorder.

Separation of methanol/benzene azeotrope mixtures is very challenging not only by the conventional distillation technique but also by adsorbents. In this work, we design and synthesize a flexible Ca-based metal–organic framework MAF-58 consisting of cheap raw materials. MAF-58 shows selective methanol-induced pore-opening flexibility. Although the opened pores are large enough to accommodate benzene molecules, MAF-58 shows methanol/benzene molecular sieving with ultrahigh experimental selectivity, giving 5.1 mmol g–1high-purity (99.99%+) methanol and 2.0 mmol g–1high-purity (99.97%+) benzene in a single adsorption/desorption cycle. Computational simulations reveal that the preferentially adsorbed, coordinated methanol molecules act as the gating component to selectively block the diffusion of benzene, offering a new gating adsorption mechanism.

TiZrTaNb-based high-entropy alloys (HEAs) are research frontier of biomedical materials due to their high hardness, good yield strength, excellent wear resistance and corrosion resistance. Sn, as an essential trace element in the human body that plays a significant role in physiological process. It has stable chemical properties and a low elastic modulus. In this study, a new material, TiZrTaNbSn HEAs, was proposed as a potential biomedical alloy. The Ti35Zr25Ta15Nb15Sn10biomedical high-entropy alloys (BHEAs) were successfully prepared through an arc melting furnace and then remelted using a German high-temperature and high-pressure apparatus under GPa-level (4 GPa and 7 GPa). The precipitation behavior of the needle-like HCP-Zr5Sn3phase that precipitates discontinuously at the grain boundary was successfully controlled. The phase constitution, microstructure, and corrosion resistance of the alloy were studied. The results show that the needle-like HCP-Zr5Sn3phase is eliminated and the (Zr, Sn)-rich nanoprecipitated phase is precipitated in the microstructure under high pressure, which leads to the narrowing of grain boundaries and consequently improves the corrosion resistance of the alloy. In addition, the formation mechanisms of (Zr, Sn)-rich nanoprecipitates in BHEAs were discussed. More Zr and Sn dissolve in the matrix due to the effect of high pressure, during the cooling process, they precipitate to form a (Zr, Sn)-rich nano-precipitated phase.

Using nanobubbles as geometrical confinements, we create a thin water film (∼10 nm) in a graphene liquid cell and investigate the evolution of its instability at the nanoscale under transmission electron microscopy. The breakdown of the water films, resulting in the subsequent formation and growth of nanodroplets, is visualized and generalized into different modes. We identified distinct droplet formation and growth modes by analyzing the dynamic processes involving 61 droplets and 110 liquid bridges within 31 Graphene Liquid Cells (GLCs). Droplet formation is influenced by their positions in GLCs, taking on a semicircular shape at the edge and a circular shape in the middle. Growth modes include liquid mass transfer driven by Plateau-Rayleigh instability and merging processes in and out-of-plane of the graphene interface. Droplet growth can lead to the formation of liquid bridges for which we obtain multiview projections. Data analysis reveals the general dynamics of liquid bridges, including drawing liquids from neighboring residual water films, merging with surrounding droplets, and merging with other liquid bridges. Our experimental observations provide insights into fluid transport at the nanoscale.

Human-specific insertions play important roles in human phenotypes and diseases. Here we reported a 446-bp insertion (Insert-446) in intron 11 of the TBC1D8Bgene, located on chromosome X, and traced its origin to a portion of intron 6 of the EBF1gene on chromosome 5. Interestingly, Insert-446 was present in the human Neanderthal and Denisovans genomes, and was fixed in humans after human-chimpanzee divergence. We have demonstrated that Insert-446 acts as an enhancer through binding transcript factors that promotes a higher expression of human TBC1D8Bgene as compared with orthologs in macaques. In addition, over-expression TBC1D8Bpromoted cell proliferation and migration through “a dual finger” catalytic mechanism (Arg538 and Gln573) in the TBC domain in vitroand knockdown of TBC1D8Battenuated tumorigenesis in vivo.Knockout of Insert-446 prevented cell proliferation and migration in cancer and normal cells. Our results reveal that the human-specific Insert-446 promotes cell proliferation and migration by upregulating the expression of TBC1D8Bgene. These findings provide a significant insight into the effects of human-specific insertions on evolution.

Byline: Miao. Duan, Dong-Dong. Xu, Hai-Long. Zhou, Hong-Ying. Fang, Wei. Meng, Yi-Ning. Wang, Zheng-Yu. Jin, Yu. Chen, Zhu-Hua. Zhang Purpose: To evaluate changes in the levator palpebrae superioris (LPS) muscle [...]

Objective: Accidental pharyngeal fishbone ingestion is a common complaint in ear, nose, and throat clinics. Approximately two-thirds of the accidentally ingested fishbones can be removed using tongue depressors and indirect laryngoscopy. However, the remaining third is challenging to identify and remove using these methods. These difficult fishbones require identification and removal via more advanced approaches. Video-guided laryngoscope is used to deal with difficult fishbones in our center. This study aimed to explore the risk factors for difficult fishbones.Methods: A prospective study was performed at a teaching hospital on 2080 patients. Univariate and multivariate analyses were performed to identify the risk factors.Results: The common fishbone locations were the tonsils (39.8%; defined as STEP-I), tongue base (37.1%), vallecula (13.3%; STEP-II), and hypopharynx (9.8%; STEP-III). With increasing STEP level, the ratio of difficult fishbones correspondingly increased (Z = 13.919, P< .001), and the proportions were 21.1%, 41.9%, and 70% in STEP-I, II, and III, respectively. In particular, fishbones in STEP-III (vs STEP-I) had a higher risk of difficult fishbones (odds ratio [OR]: 11.573, 95% CI: 7.987-16.769). Complaints of neck pain (yes vs no), foreign body sensation (yes vs no), and shorter length of fishbones always had a lower risk of difficult fishbones (OR: 0.455, 95% CI: 0.367-0.564; OR: 0.284, 95% CI: 0.191-0.422; OR: 0.727, 95% CI: 0.622-0.85). Missing teeth (yes vs no), swallowing behavior after fishbone ingestion (yes vs no), and male patients (vs female) had a higher risk of difficult fishbones (OR: 1.9, 95% CI: 1.47-2.456; OR: 1.631, 95% CI: 1.293-2.059; OR: 1.278, 95% CI: 1.047-1.56).Conclusions: Neck pain, foreign body sensation, fishbone length, patient age and sex, tooth status, and swallowing behavior after fishbone ingestion are independent risk factors for difficult fishbones.

In this paper, the Fe/Si reduction efficiency, Gd/Mn alloying efficiency, and corrosion susceptibility of the Mg-xMn-4.0Gd alloy were investigated. The results reveal that adding Mn gives a more prominent Fe removal effect under the conventional smelting processes. Neither the amount of Gd addition nor excessive Mn addition is sufficient for the continued strengthening of the Fe removal effect. The alloying efficiency of Mn increased and then decreased as a result of adding Mn alone to mixtures of Mn and Gd elements, while the alloying efficiency of Gd elements gradually diminished. An appropriate amount of Mn addition is beneficial for efficiently improving the corrosion resistance of the alloy. The extruded Mg-0.8Mn-4.0Gd alloy has more outstanding corrosion resistance, with a CRWeighet Lossof 4.48 ± 0.33 mg/(cm2·d) and CRHydrogen Evolutionof 2.01 ± 0.31 ml/(cm2·d). The corrosion susceptibility of the extruded Mg-xMn-4.0Gd alloy mainly hinges on the grain size, Gd solid solubility, and texture intensity of basal plane I(0002).

The study investigates the influence of ultrasound on the microstructure and properties of AlCoCrFeNi fabricated by laser cladding. The results indicate that the grain size of AlCoCrFeNi prepared by ultrasonic assistance is smaller than that prepared without ultrasound. Moreover, employing ultrasound in the fabrication process of AlCoCrFeNi results in an improvement in its electrochemical corrosion resistance. This enhancement can be attributed to the homogenization of the microstructure and the reduction of microgalvanic couples. The wear resistance of AlCoCrFeNi is enhanced with the increase in ultrasound amplitude. The sample prepared using a 15 μm ultrasonic amplitude demonstrates the lowest friction coefficient of 0.3876 and the minimal wear loss of 40.8 mg. The tensile strength and elongation of AlCoCrFeNi are improved as the ultrasonic amplitude increases. The sample prepared using a 15 μm ultrasonic amplitude demonstrates the highest tensile strength and elongation, measuring 1039 MPa and 16.2%, respectively. The enhancement of mechanical properties can be attributed primarily to the grain refinement and the reduction of as-cast defects.

Six new sesquiterpene quinone/hydroquinone meroterpenoids, arenarialins A–F (1–6), were isolated from the marine sponge Dysidea arenariacollected from the South China Sea. Their chemical structures and absolute configurations were determined by HRMS and NMR data analyses coupled with DP4+ and ECD calculations. Arenarialin A (1) features an unprecedented tetracyclic 6/6/5/6 carbon skeleton, whereas arenarialins B–D (2–4) possess two rare secomeroterpene scaffolds. Arenarialins A–F showed inhibitory activity on the production of inflammatory cytokines TNF-α and IL-6 in LPS-induced RAW264.7 macrophages with arenarialin D regulating the NF-κB/MAPK signaling pathway.

Morphological rearrangement of the endoplasmic reticulum (ER) is critical for metazoan mitosis. Yet, how the ER is remodeled by the mitotic signaling remains unclear. Here, we report that mitotic Aurora kinase A (AURKA) employs a small GTPase, Rab1A, to direct ER remodeling. During mitosis, AURKA phosphorylates Rab1A at Thr75. Structural analysis demonstrates that Thr75 phosphorylation renders Rab1A in a constantly active state by preventing interaction with GDP-dissociation inhibitor (GDI). Activated Rab1A is retained on the ER and induces the oligomerization of ER-shaping protein RTNs and REEPs, eventually triggering an increase of ER complexity. In various models, from Caenorhabditiselegansand Drosophilato mammals, inhibition of Rab1AThr75phosphorylation by genetic modifications disrupts ER remodeling. Thus, our study reveals an evolutionarily conserved mechanism explaining how mitotic kinase controls ER remodeling and uncovers a critical function of Rab GTPases in metaphase.

Ti2AlNb intermetallic alloys, which belong to the titanium aluminum (TiAl) family, are currently being extensively researched and promoted in the aerospace industry because of their exceptional properties, including low density, high-temperature strength, and excellent oxidation resistance. However, the excellent fracture toughness of the material leads to the formation of surface defects during machining, thereby affecting the quality of the machined surface. In this study, Ti2AlNb intermetallic alloys were subjected to side-milling trials to investigate the influence of tool coating and tool wear on both the machined surface quality and chip morphology. Specifically, the tool life, machined surface roughness, surface morphology, surface defects, and chip morphology were investigated in detail. The results indicated that the tool coating provided a protective effect, resulting in a threefold increase in the service life of the coated end mill compared to that of the uncoated one. A coated end mill yields a superior machined surface topography, as evidenced by reduced roughness and a more consistent morphology. Tool wear has a significant effect on the morphology of machined surfaces. The occurrence of material debris and feed marks became increasingly severe as the tool wore off. The chip morphology was not significantly affected by the tool coating. However, tool wear results in severe tearing along the chip edge, obvious plastic flow on the non-free surface, and a distinct lamellar structure on the free surface.

It is necessary to improve the surface performance of bearing rings and extend the service life of bearings. In this study, ultrasonic vibration-assisted grinding (UVAG) was applied to process GCr15SiMn bearing steel, considering the effects of grinding-wheel wear, overlap of abrasive motion tracks under ultrasonic conditions, elastic yield of abrasives, and elastic recovery of the workpiece on the machined surface. In addition, a novel mathematical model was established to predict surface roughness (Ra). The proposed model was validated experimentally, and the predicted and experimental results showed similar trends under various processing parameters, with both within an error range of 12%–20%. The relationships between the machining parameters and Rafor the two grinding methods were further investigated. The results showed that increases in the grinding speed and ultrasonic amplitude resulted in a decrease in Ra, whereas increases in the grinding depth and workpiece speed resulted in an increase in Ra. Furthermore, the Ravalues obtained using the UVAG method were lower than those of conventional grinding (CG). Finally, the influence of ultrasonic vibration on the surface topography was investigated. Severe tearing occurred on the CG surface, whereas no evident defects were observed on the ultrasonically machined surface. The surface quality was improved by increasing the ultrasonic amplitude such that it did not exceed 4 μm, and a further increase in ultrasonic amplitude deteriorated the surface topography. Nevertheless, this improvement was superior to that of the CG surface and was consistent with the variation in Ra.

Ferroptosis holds significant potential for application in cancer therapy. However, ferroptosis inducers are not cell-specific and can cause phospholipid peroxidation in both tumor and non-tumor cells. This limitation greatly restricts the use of ferroptosis therapy as a safe and effective anticancer strategy. Our previous study demonstrated that macrophages can engulf ferroptotic cells through Toll-like receptor 2 (TLR2). Despite this advancement, the precise mechanism by which phospholipid peroxidation in macrophages affects their phagocytotic capability during treatment of tumors with ferroptotic agents is still unknown. Here, we utilized flow sorting combined with redox phospholipidomics to determine that phospholipid peroxidation in tumor microenvironment (TME) macrophages impaired the macrophages ability to eliminate ferroptotic tumor cells by phagocytosis, ultimately fostering tumor resistance to ferroptosis therapy. Mechanistically, the accumulation of phospholipid peroxidation in the macrophage endoplasmic reticulum (ER) repressed TLR2 trafficking to the plasma membrane and caused its retention in the ER by disrupting the interaction between TLR2 and its chaperone CNPY3. Subsequently, this ER-retained TLR2 recruited E3 ligase MARCH6 and initiated the proteasome-dependent degradation. Using redox phospholipidomics, we identified 1-steaoryl-2-15-HpETE-sn-glycero-3-phosphatidylethanolamine (SAPE-OOH) as the crucial mediator of these effects. Conclusively, our discovery elucidates a novel molecular mechanism underlying macrophage phospholipid peroxidation-induced tumor resistance to ferroptosis therapy and highlights the TLR2-MARCH6 axis as a potential therapeutic target for cancer therapy.

Autonomous indoor humidity control is gaining more and more attention but is limited by the trade-offs among pore volume, pore size and water stability of water adsorbents. We solve this problem by using a unique coordination network topology combined with hydrolytically stable M(III) carboxylate clusters. By extending the ligand length from 9.0 to 11.2 and 13.7 Å, the pore volume significantly increases from 0.99 to 1.40 and 1.78 cm3g−1, which proportionally increases the saturated water adsorption capacity. Meanwhile, the pore size slightly increases from 10.4 to 11.0 and 13.5 Å, which restricts the isotherm inflection pressure and hysteresis width to meet the requirement of indoor humidity control. Large single-crystals suitable for X-ray diffraction studies were obtained by using Fe(III) salts, while isostructural frameworks with sufficiently high water stabilities were synthesized by using Cr(III) salts, which offer record working capacity of 0.90 and 1.10 g g−1for indoor humidity control.

Objective: To investigate the serum lipid profiles of patients with localized osteosarcoma around the knee joint before and after neoadjuvant chemotherapy. Methods: After retrospectively screening the data of 742 patients between January 2007 and July 2020, 50 patients aged 13 to 39 years with Enneking stage II disease were included in the study. Serum lipid levels, including total cholesterol (TC), triglycerides (TG), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), lipoprotein-α [Lp(a)], and apolipoprotein A1, B, and E (ApoA1, ApoB, and ApoE), and clinicopathological characteristics were collected before and after neoadjuvant chemotherapy. Results: The mean levels of TC, TG, and ApoB were significantly increased following neoadjuvant chemotherapy (16%, 38%, and 20%, respectively, vs.pretreatment values; P&lt;0.01). The mean levels of LDL-C and ApoE were also 19% and 16% higher, respectively (P&lt;0.05). No correlation was found between the pretreatment lipid profile and the histologic response to chemotherapy. An increase in Lp(a) was strongly correlated with the Ki-67 index (R=0.31, P=0.023). Moreover, a trend toward longer disease-free survival (DFS) was observed in patients with decreased TG and increased LDL-C following chemotherapy, although this difference was not statistically significant (P=0.23 and P=0.24, respectively). Conclusion: Significant elevations in serum lipids were observed after neoadjuvant chemotherapy in patients with localized osteosarcoma. There was no prognostic significance of pretreatment serum lipid levels on histologic response to neoadjuvant chemotherapy. The scale of increase in serum Lp(a) might have a potential prognostic role in osteosarcoma. Patients with increased LDL-C or reduced TG after chemotherapy seem to exhibit a trend toward favorable DFS.

With the development of autonomous underwater vehicles, the research of underwater acoustic positioning and navigation technology is becoming increasingly important. However, most underwater positioning systems use the traditional acoustic response synchronization method, which leads to insufficient positioning real-time performance and refresh rate. To solve this problem, this article proposes a real-time global synchronization mechanism with high-precision atomic clocks, which can realize one positioning through one-way propagation, so that the positioning efficiency is at least doubled. To further improve the positioning accuracy, an M-sequence-based phase offset modulation method is proposed to facilitate beacon identification. Consequently, a normalized signal matching capture algorithm against Doppler effect is designed, and the positioning solution is fused with the real-time sound ray bending compensation mechanism. Based on the abovementioned content, we developed an FPGA-based real-time synchronous parallel underwater positioning and navigation system, which uses FPGA+MCU architecture to accelerate signal processing operations in a low power and parallel way. The test results in the South China Sea show that the operating range of the system can reach 8 km, the positioning refresh rate can reach 0.2 Hz, and the relative average position error is 0.25%, confirming the effectiveness of the designed system in industrial applications.

The knowledge of the phase selection and microstructure evolution of Zr–Fe eutectic alloys is still poorly understood. The presumed eutectic alloy with a nominal composition of Zr76.0Fe24.0was discovered to contain a significant proportion of α-Zr dendrites. Hereby, phase selection and microstructure evolution dependance on composition for Zr–Fe eutectic alloys was experimentally determined by using differential scanning calorimetry (DSC) and meticulous electron microscopes. Eight alloys, spanning the composition range of 73.5–74.7% Zr, were examined to investigate microstructure evolution and non-isothermal crystallization kinetics. Results indicate that in alloys ranging from Zr73.5Fe26.5to Zr73.9Fe26.1, the primary FeZr2phase demonstrates preferential growth, followed by eutectic microstructure formation during liquid alloy solidification. The volume fraction of FeZr2dendrites decreases as the Zr content increases. Conversely, in alloys ranging from Zr74.0Fe26.0to Zr74.7Fe25.3, primary β-Zr dendrites preferentially grow, followed by a eutectic reaction in the remaining liquid phase. The content of α-Zr dendrites reduces with decreasing Zr content. As mentioned above, a critical composition range for phase selection is defined as ZrxFe100.0−x(73.9 < x< 74.0).

The efficient extraction of phthalic acid esters (PAEs) is challenging due to their extremely low concentration, complicated matrices and hydrophilicity. Herein, hollow microspheres, as an ideal coating, possess significant potential for solid-phase microextraction (SPME) due to their fascinating properties. In this study, multiwalled carbon nanotube hollow microspheres (MWCNT-HMs) were utilized as a fiber coating for the SPME of PAEs from tea beverages. MWCNT-HMs were obtained by dissolving the polystyrene (PS) cores with organic solvents. Interestingly, MWCNT-HMs well maintain the morphology of the MWCNTs@PS precursors. The layer-by-layer (LBL) assembly of MWCNTs on PS microsphere templates was achieved through electrostatic interactions. Six PAEs, di-ethyl phthalate (DEP), di-iso-butyl phthalate (DIBP), di-n-butyl phthalate (DBP), benzyl butyl phthalate (BBP), di-2-ethylhexyl phthalate (DEHP) and di-n-octyl phthalate (DOP), were selected as target analytes for assessing the efficiency of the coating for SPME. The stirring rate, sample solution pH and extraction time were optimized by using the Box–Behnken design. Under optimal working conditions, the proposed MWCNT-HMs/SPME was coupled with gas chromatography-tandem mass spectrometry (GC-MS/MS) to achieve high enrichment factors (118–2137), wide linearity (0.0004–10 μg L−1), low limits of detection (0.00011–0.0026 μg L−1) and acceptable recovery (80.2–108.5%) for the detection of PAEs. Therefore, the MWCNT-HM coated fibers are promising alternatives in the SPME method for the sensitive detection of PAEs at trace levels in tea beverages.

Particle-reinforced metal matrix composites (PMMCs) exhibit exceptional mechanical properties, rendering them highly promising for extensive applications in aerospace, military, automotive, and other critical sectors. The distinct physical properties of the matrix and reinforcement result in a poor machining performance, particularly owing to the continuous increase in the particle content of the reinforcement phase. This has become a major obstacle in achieving the efficient and precise machining of PMMCs. The grinding process, which is a highly precise machining method, has been extensively employed to achieve precision machining of metal matrix composites. Firstly, the classification of PMMCs is presented, and the grinding removal mechanism of this material is elaborated. Recent studies have examined the impact of various factors on the grinding performance, including the grinding force, grinding temperature, grinding force ratio, specific grinding energy, surface integrity, and wheel wear. The application status of various grinding methods for PMMCs is also summarized. Finally, the difficulties and challenges in achieving high-efficiency precision grinding technology for PMMCs are summarized and discussed.

For atmospheric melting cast Cu–15Ni–8Sn alloy, hot extrusion tests were conducted on ingots of Cu–15Ni–8Sn alloy with varying extrusion ratios (5, 12 and 16) following homogenization and annealing. The investigation employed mechanical property tests, scanning electron microscopy and transmission electron microscopy to analyze the mechanical characteristics, dynamic recrystallization and twinning behaviors of the alloys subjected to different extrusion ratios. The findings revealed a reduction in the average grain size of the alloy as the extrusion ratio increased. The alloy undergoes dynamic recrystallization during hot extrusion, and the degree of recrystallization of the alloy escalated with higher extrusion ratios. The alloy underwent completely recrystallized at an extrusion ratio of 16, primarily driven by discontinuous dynamic recrystallization (DDRX). In addition, the alloy generated twins during the DRX process, and the twin boundaries provided favorable sites for the nucleation of DRX grains, which promoted the DRX of the alloy. Notably, at an extrusion ratio of 16, the alloy demonstrated impressive mechanical properties, with an ultimate tensile strength of 836 MPa and an elongation of 13.5 %. These results presented a substantial enhancement, showcasing a 54 % increase in the extruded ultimate tensile strength and a 350 % increase in the elongation compared to that of the alloy in the homogenized annealed state.

Hybrid modular multilevel converters (HMMC) have emerged recently as an improvement over conventional MMCs due to their lower submodule capacitor sizing, smaller semiconductor count, and lower losses. HMMCs can achieve such advantages, while still maintaining modularity due to their intelligent use of line-frequency-switching medium-voltage switches in addition to the high-frequency low-voltage switch-based submodules. HMMC open-loop operation and performance are well elaborated in literature, but HMMC closed-loop submodule capacitor (SM-C) voltage control is not yet well demonstrated. Closed-loop balancing for HMMC SM-C is especially challenging as the operating mode changes every half-line cycle, making a unified continuous model and subsequent control development challenging. Furthermore, some HMMCs do not have a circulating current path to exchange energy among different arms/phases. This poses an additional challenge for energy transfer between HMMC SM-C. This article resolves these challenges by first proposing a converter model and then developing new control ideas. Novel methods to balance SM-C using midpoint-voltage and interphase circulating-currents are developed for HMMCs. Additionally, the model is utilized to explain power flows, elaborating on the fundamentals behind much lower SM-C size in HMMC compared to MMCs for the same operation. The developed model and controls are verified extensively on a medium-voltage 20 kW laboratory prototype.

Power semiconductors need to momentarily operate in the active area of DC solid-state circuit breakers (DC-SSCB) to limit the fault current. During this interval, a severe voltage oscillation is observed, leading to the DC-SSCB overstress and eventually failure. This article aims to understand the mechanism causing the voltage oscillation and devise solutions to suppress it. First, a MATLAB/Simulink model is built with comprehensive considerations of power semiconductors, parasitics, gate drive, and metal oxide varistor (MOV). Then a sensitivity study is performed to identify the critical impact factor(s) causing the voltage oscillation. Afterward, three suppression methods using enhanced gate drive circuitry are proposed and compared. Finally, test results based on a 2 kV/1 kA SSCB prototype demonstrate the accuracy of the derived model and the effectiveness of the proposed oscillation mitigation methods.

Medium voltage (MV) and high voltage (HV) rectifiers demonstrate lower cost and volume as well as reversal power protection compared to the bidirectional counterparts in the unidirectional ac/dc applications, such as HVdc transmission, MVdc shipboard system, subsea oil and gas production power systems, etc. Traditional modular multilevel converter (MMC) is good candidate, but suffers from large number of submodules (SMs) and capacitor size. Recently, the hybrid multilevel rectifiers (HMRs) consisting of the HV diode and MMC structure have evolved and gained significant interests. The HV diode could replace some SMs in MMC, implying improved power density and efficiency. In this article, three typical HMR topologies are selected, and each of them uses a different configuration and offers unique advantages. Therefore, this article illustrates the operation principles, and gives the comparative performance evaluation of these HMRs based on key metrics such as device number, capacitor energy storage requirement, and semiconductor losses. In this way, the favorable working conditions of these HMRs could be identified, and the most suitable applications for each configuration could be suggested. The simulation as well as the experimental results are provided to validate these HMRs. Overall, the presented analysis can provide a point of reference and a useful framework for the future developments of HMRs.

The Cu/SiO2catalysts were prepared by co-precipitation and tested for hydrogenation of furfural to furfuryl alcohol in a fixed bed reactor. The deactivation mechanism of the catalysts was investigated by characterization of H2-TPR, ICP-OES, XPS, TG, Raman and TEM. Under the conditions of atmospheric pressure, reaction temperature of 140 °C, mass space velocity of 2.4 h–1and the molar ratio of hydrogen to furfural of 9.7, the furfural conversion was higher than 97% in the first 5 h. However, the conversion of furfural decreased rapidly from 96% to 32% after 21 h of reaction, indicating that Cu/SiO2catalyst was rapidly deactivated. The factors for the deactivation of Cu/SiO2catalyst were the agglomeration and sintering of the active component copper. Moreover, the carbon deposition on the catalyst surface resulted in the covered active site Cu0.

As advances in semiconductor, dielectric, and magnetic materials enhance the power density of power conversion systems, the emphasis on efficient cooling solutions becomes paramount. Effective thermal management is vital as it directly influences the power density and reliability of power inverters. This is especially crucial for high-altitude motor drives, given the challenges posed by reduced air density. This article provides a design process of thermal management for high-density high-power inverters. Thermal models for different scenarios are derived, and the hotspot temperature can be estimated under different cooling conditions. To demonstrate the proposed design process, a 200-kW three-level T-type propulsion inverter designed for an altitude of 7620 m (25 000 ft) is used to present the thermal designs. Several thermal mitigation techniques are also introduced. A critical finding is the potential for stagnating air spaces to produce localized hotspots in areas such as the busbar, gate-driver boards, and terminals. Historically, these hotspots have been overlooked, yet they can significantly degrade overall thermal performance and system reliability. To address the thermal issue of hotspots caused by stagnating air space, several solutions are proposed. Of these, the localized forced cooling air duct (AD) solution is selected in this work. By optimizing both internal and external airflows, the hotspot temperature in the stagnating air space is reduced by 37% using the designed AD without oversizing the overall cooling system. Moreover, based on full-power experimental thermal tests, we demonstrate that the inverter’s hotspot temperature within a sealed enclosure can be kept below 130 °C in an environment of 75 °C and at an altitude of 7620 m. The culmination of our research validates the efficacy of the proposed design process.

In this study, ultrafine/nano W–Y2O3composite powders were synthesized by spray drying, roasting and two-step hydrogen reduction using ammonium metatungstate and yttrium nitrate as raw materials. The mechanism of the influence of Y2O3on the growth of WO2.72and the particle refinement of tungsten powder is discussed. The effect of Y2O3particles on the reduction behavior of tungsten powder was investigated using scanning electron microscopy to study the near surface morphology and X-ray diffraction for phase ID (composition) and crystal structural changes for the reduced powders at each step. The results show that the doping of 0.3 wt.% Y2O3can significantly increase the aspect ratio of WO2.72in the first step of hydrogen reduction. Moreover, Y2O3can effectively inhibit the growth of tungsten particles in the hydrogen reduction process. Therefore, The Y2O3-doped tungsten powders have finer particles and a narrower particle size distribution range than the undoped powders. The average particle diameter of 0.3 wt.% Y2O3doping tungsten powder was in the range of 90–120 nm.

ABSTRACTThis study presents a Computational Fluid Dynamics (CFD) based biofiltration model to investigate the airflow distribution and the impact of bed flow unevenness (BFU) on the removal of Volatile Organic Compounds (VOCs) in biofilters. The biofiltration model consists of a gas flow sub-model and a VOCs removal sub-model, which were validated by pilot-scale experiments. The model was used to examine the quantitative relationship among reactor dimensions, including the width to height ratio of the filter bed and empty bed residence time (EBRT), BFU, and performance for VOCs biofilters. Simulation results demonstrate that the flow unevenness index (FUI) of the packing layer changes from 0.06 to 0.48 m2‧s−1with reactor dimension changes. With an increase in the width to height ratio at a constant EBRT, FUI increases, BFU changes, and flow velocity fluctuation on the cross-section becomes larger, leading to a reduction of about 10% in VOCs removal efficiency. Concentration distribution of VOCs becomes uneven in the horizontal direction. At a constant width to height ratio of the filter bed, an increase in EBRT causes an increase in FUI, leading to a decrease in VOCs removal efficiency. When the width to height ratio is 0.5, velocity fluctuation of filter bed cross-section is small, the concentration of VOCs decreases evenly across the filter bed layer, and FUI is at a low level (0.06–0.11 m2‧s−1).Implication: In this manuscript, a biofiltration model of VOCs biofilter based on CFD has constructed and validated. And the manuscript gave the quantitative relationship among reactor dimension, bed flow unevenness and performance for VOCs biofilters for the first time. This study can lead to enhanced VOCs removal efficiency and improved overall performance of biofilters in practical engineering applications.

Icing poses significant operational challenges in laser radar, antennas, and aircraft wings. However, there is an urgent demand for developing graphene-based de-icing surfaces with high absorption, excellent photothermal conversion ability, and low ice adhesion. Herein, laser-induced graphene (LIG) for lubricant-infused slippery photothermal de-icing surfaces has been developed. The de-icing surfaces were prepared by laser pyrolysis and lubricant infusion. After laser pyrolysis, the polyimide substrate was converted into LIG with porous nanostructures, high absorption (>90%), and hydrophobicity, which is suitable for fabricating lubricant-infused slippery photothermal de-icing surfaces. Due to the existing lubricant, the lubricant-infused slippery photothermal de-icing surfaces show low ice adhesion upon light irradiation. This work shows great potential in passive frosting/icing prevention.

The multilevel T-type inverter exhibits an inherent challenge of unbalanced power loss distribution among switches. This discrepancy in loss distribution is greatly influenced by the modulation index and the power factor, leading to increased system costs due to the overdesign of power devices and cooling systems based on worst-case scenarios. Furthermore, this loss imbalance will cause uneven device lifetimes, ultimately compromising the overall reliability of the converter system. To address the issue of loss imbalance, this article proposes a comprehensive and generic modulation scheme for the multilevel T-type inverter. The proposed scheme enables the balancing of switching and conduction losses for all switches in the inverter, regardless of the power factor and modulation index, as long as the modulation index is below a specific threshold. Importantly, the proposed scheme ensures that the losses of each individual device and the total converter loss are independent of the power factor and modulation index, which only requires knowledge of the on-resistance of the power mosfet. Additionally, the proposed modulation scheme effectively reduces the total loss of the inverter and naturally balances the neutral point potential. The proposed modulation scheme is validated in a 200 kW SiC-based three-level T-type inverter.

The Cu–15Ni–8Sn alloy ingot was prepared in the medium-frequency induction melting furnace. The hot extruded alloy was treated by solid solution at 840 °C for 60 min and aging at 400 °C for different times (0 miñ480 min). The effect of aging time on the evolution of the nanophase of Cu–15Ni–8Sn alloy and the strengthening-toughening mechanism were studied. The results show that at the beginning of aging, the alloy undergoes spinodal decomposition, the wavelength of the modulated structure is approximately 3∼7 nm, the ordered phase transformation of D022and L12occurs simultaneously, and the ordered phase size is approximately 5 nm. With the extension of aging time, the modulated structure became coarser, and the wavelength of the modulated structure increased to 5–9 nm. At the same time, the D022ordered phase changed to the L12ordered phase, and a continuous distribution of elliptical discontinuous precipitation appeared at the grain boundary. The ratio of the long and short axes of the discontinuous precipitation was approximately 4.7. In the late aging period, the D022ordered phase was basically transformed into the L12ordered phase, and discontinuous precipitation, which is incompatible with the matrix, extended into the crystal. After 120 min of aging at 400 °C, the hardness, strength, and elongation of the alloy are 105.4 HRB, 839.8 MPa and 9.6 %, respectively. The peak-aging states D022and L12coexist in an orderly phase at the nanoscale, and this nanoscale strengthening phase is completely integrated with the matrix, which improves the strength and toughness of the alloy. The research results can provide support for the development of high-performance copper alloys in the ocean.