•The motion characteristics of droplets in hybrid arc space are described.•The action of metal vapor ejected from laser keyhole on droplet is analyzed.•The laser plasma compresses the arc and leads ...to the increase of the electromagnetic resistance of the droplet transfer.
The droplet transfer, plasma morphology and droplet morphology of laser arc hybrid welding process are collected and analyzed using high speed camera. The force magnitude and acceleration of motion droplets in the arc space are calculated by the image processing and mathematical calculations. The value and distribution of the recoil force from the metal vapor on droplets are calculated. The results show that the globular transfer mode corresponds to the welding current is approximate 180 A; the streaming transfer mode corresponds to the welding current is approximate 200 A. The laser has a compress effect on the arc, and the compression on the surface of the weld pool is stronger. The acceleration of the droplet detachment from wire is 70 m/s2 and 50 m/s2 for arc welding and laser arc hybrid welding separately. In the actual welding process, the reaction force of metal vapor on molten droplets is very small, when the distance between droplet and keyhole in the surface of the weld pool is 3 mm. The pressure difference on the surface between upper and lower of the droplet is great, which results the droplet coalescence and the transfer frequency slows down.
A CoS2/graphene nanoarchitecture was synthesized by a facile one-step hydrothermal route using graphite oxide, thioacetamide, and CoCl2·6H2O as the starting materials. The growth of CoS2 and the ...reduction of the graphite oxide occur simultaneously. CoS2 nanocrystals with a size of 100−150nm are uniformly anchored on the both sides of the graphene nanosheets, forming a unique CoS2/graphene hybrid nanostructure. The electrochemical tests showed that the nanocomposite exhibits obviously enhanced Li-storage properties compared with bare CoS2. The improvement in electrochemical properties could be attributed to the formation of two-dimensional conductive networks, homogeneous dispersion and immobilization of CoS2 nanoparticles, and the enhanced wetting of active material with the electrolyte by in situ introduced graphene nanosheets.
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► We synthesized CoS2/graphene nanoarchitecture by a facile one-pot route. ► CoS2/graphene exhibits improved Li-storage properties than bare CoS2. ► The graphene offers combined buffering, conducting, and immobilizing effects.
This study explores the laser-arc hybrid welding process of high nitrogen steel (HNS) in order to circumvent the problem of welding porosity. The influence of welding heat input on welding porosity ...has been elucidated by analyzing the changes in the morphological characteristics of the laser keyhole and the molten pool temperature. The results show that the pore ratio increases with a rise in laser power. Meanwhile, the pore ratio first decreases and then increases as the welding current intensifies. Additionally, it decreases as the welding speed and defocus amount increase. The lowest pore ratio of the weld is considered as the desired value, and the response surface method (RSM) is used to optimize the heat input parameters. When the laser power ranges from 2.80 to 2.85 kW, the welding current becomes 260 A, welding speed ranges from 0.73 to 0.80 m/min, defocus amount ranges from 0 to 1 mm, and pore ratio of the weld exhibits its minimum value (4.29 to 4.67%).
A biological process called epithelial-mesenchymal transition (EMT) allows epithelial cells to change into mesenchymal cells and acquire some cancer stem cell properties. EMT contributes ...significantly to the metastasis, invasion, and development of treatment resistance in cancer cells. Current research has demonstrated that phytochemicals are emerging as a potential source of safe and efficient anti-cancer medications. Phytochemicals could disrupt signaling pathways related to malignant cell metastasis and drug resistance by suppressing or reversing the EMT process. In this review, we briefly describe the pathophysiological properties and the molecular mechanisms of EMT in the progression of cancers, then summarize phytochemicals with diverse structures that could block the EMT process in different types of cancer. Hopefully, these will provide some guidance for future research on phytochemicals targeting EMT.
Catalysts play a critical role in improving the hydrogen storage kinetics in Mg/MgH
2
system. Exploring highly efficient catalysts and catalyst design principles are hot topics but challenging. The ...catalytic activity of metallic elements on dehydrogenation kinetics generally follows a sequence of Ti>Nb>Ni>V>Co>Mo. Herein, we report a highly efficient alloy catalyst composed of low-active elements of Mo and Ni (i.e. MoNi alloy) for MgH
2
particles. MoNi alloy nanoparticles show excellent catalytic effect, even outperforming most advanced Ti-based catalysts. The synergy between Mo and Ni elements can promote the break of Mg-H bonds and the dissociation of hydrogen molecules, thus significantly improves the kinetics of Mg/MgH
2
system. The MoNi-catalyzed Mg/MgH
2
system can absorb and release 6.7 wt.% hydrogen within 60 s and 10 min at 300 °C, respectively, and exhibits excellent cycling stability and low-temperature hydrogen storage performance. This study provides a strategy for designing efficient catalysts for hydrogen storage materials using the synergy of metal elements.
(B,N)-codoped TiO2 was prepared by the oxidation method using TiBN powder as a precursor. The oxidation of TiBN powder particles started with the surface, producing a high-Ti low-O compound Ti2O3. ...Meanwhile, accompanied by the migration and oxidation of B, the oxidative process gradually extended towards the interior, giving rise to the formation of (B,N)-codoped TiO2. XRD analysis revealed that, in oxidative products, the residual TiBN phase was structurally similar to Ti4N3B2, suggesting that Ti had diffused and migrated outwards from TiBN. On this basis, an oxidative model was built for TiBN particles. The oxidation of TiBN consisted of two processes: chemical reaction (TiBN→Ti2O3→TiO2) and organizational structure evolution (TiBN→Ti4N3B2). The prepared TiO2 was dominated by rutile form and also contained small amounts of anatase and residual TiBN. (B,N) Codoping increased the lattice parameter of rutile TiO2. Organizational structure was found to be related to the parameters of the oxidative process. Pure rutile TiO2 could be obtained from TiBN powder under 800°C + 2h oxidative treatment, and the interplanar spacings of its (110), (101), (211), and (111) planes were 0.324877 nm, 0.24875 nm, 0.16874 nm, and 0.21873 nm, respectively. These interplanar spacings were greater than the interplanar spacings of TiO2 produced through the oxidation of TiN under equal conditions, which was attributable to (B,N) codoping in TiO2. According to direct observations by high-resolution transmission electron microscopy (HRTEM), the organizational structure of TiO2 particles demonstrated the fine size and elliptical boundary and contained amorphous layers. This study offers a new approach to (B,N) codoping in TiO2. The (B,N)-codoped TiO2 with high photocatalytic efficiency obtained in this study can be applied in environmental and energy fields.
The significant disparity in refractive index between silicon nitride (Si3N4) powder and resin poses a formidable challenge in the formulation of stable ceramic slurry with high solid content and low ...viscosity. This research paper systematically investigates the oxidation pretreatment of Si3N4 powder and the modification process of the silane coupling agent, with a particular focus on their impacts on the rheological and curing properties of the ceramic slurry. Furthermore, the study thoroughly examines the effects of various functional group resin compounds, dispersant types, and dosages on the rheological and curing properties of the ceramic slurry. By optimizing the surface modification process of silicon nitride (Si3N4) and formulating an appropriate composition for the silicon nitride (Si3N4) slurry, this paper successfully prepares a Si3N4 ceramic slurry with outstanding curing performance, low viscosity, and a solid content of 44 vol%. The application of photocuring molding technology enables the production of Si3N4 ceramic components characterized by high precision, excellent surface quality, and intricate geometries. Moreover, this study establishes a comprehensive understanding of the relationship between the refractive index of silicon nitride ceramic slurry and essential parameters, including photocuring process variables and slurry properties. This achievement provides valuable technical guidance for the preparation and printing of silicon nitride ceramic slurry.
The rapid development of microelectronic devices has stimulated an increasing demand for micro-energy storage devices, typically, micro-supercapacitors (MSCs). Despite recent advances, the ...fabrication of MSCs using a facile, scalable and inexpensive method still remains challenging. In this work, we use a facile screen printing technique to fabricate flexible all-solid-state MSCs using N-doped reduced graphene oxide (rGO) as the electrode material. The effective area of MSCs and the thickness of the active material are only 0.396 cm super(2) and 10 mu m, respectively. The MSCs can deliver a high specific areal capacitance of 3.4 mF cm super(-2), which is among the high values of graphene-based materials for all-solid-state MSCs reported so far. Easy fabrication and good performance make MSCs promising on-chip energy storage devices.
Great expectation is placed on sodium‐ion batteries with high rate capability to satisfy multiple requirements in large‐scale energy storage systems. However, the large ionic radius and high mass of ...Na+ hamper its kinetics in the case of diffusion‐controlled mechanisms in conventional electrodes. In this study, a unique intercalation pseudocapacitance has been demonstrated in low‐vacancy copper hexacyanoferrate, achieving outstanding rate capability. The minimization of the Fe(CN)6 vacancy enables unhindered diffusion pathways for Na+ and little structural change during the Fe2+/Fe3+ redox reaction, eliminating solid‐state diffusion limits. Moreover, the Cu+/Cu2+ couple is unexpectedly activated, realizing a record capacity for copper hexacyanoferrate. A capacity of 86 mAh g−1 is obtained at 1 C, of which 50 % is maintained under 100 C and 70 % is achieved at 0 °C. Such intercalation pseudocapacitance might shed light on exploiting high‐rate electrodes among Prussian blue analogs for advanced sodium‐ion batteries.
Into the blue: Intercalation pseudocapacitance is demonstrated in Prussian blue analogs for sodium storage of copper hexacyanoferrate. The minimization of the Fe(CN)6 vacancy in copper hexacyanoferrate enables unhindered diffusion pathways for Na+ and little structural change during the Fe2+/Fe3+ redox reaction, eliminating solid‐state diffusion limits. High reversible capacity, outstanding rate capability, and long cycle life are achieved simultaneously.
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