Plasma-assisted aerogel interface engineering enables uniform Zn^(2+)flux and fast desolvation kinetics toward zinc metal batteries

The poor reversibility of Zn anodes induced by dendrite growth,surface passivation,and corrosion,severely hinders the practical applicability of Zn metal batteries.To address these issues,a plasmaassisted aerogel(PAG)interface engineering was proposed as efficient ion transport modulator that can simultaneously regulate uniform Zn^(2+)flux and desolvation behavior during battery operation.The PAG with ordered mesopores acted as an ion sieve to homogenize Zn deposition and accelerate Zn^(2+)flux,which is favorable for corrosion resistance and dendrite suppression.Importantly,the plasma-assisted aerogel with abundant hydrophilic groups can facilitate the desolvation kinetics of Zn^(2+)due to the multiple hydrogen-bonding interaction with the activated water molecules,thus accelerating the Zn^(2+)migration kinetics.Consequently,the Zn/Zn cell assembled with PAG-modified separator demonstrates stable plating and stripping behavior(over 1400 h at 1 mA cm^(-2))and high Coulombic efficiency(99.8%at1 mA cm^(-2)after 1100 cycles),and the Zn‖MnO_(2)full cell shows excellent long-term cycling stability and maintains a high capacity of 154.9 mA h g^(-1)after 1000 cycles at 1 A g^(-1).This study provides a feasible approach for the large-scale fabrication of aerogel functionalized separators to realize ultra-stable Zn metal batteries.

Plasma induced dynamic coupling of microscopic factors to collaboratively promote EM losses coupling of transition metal dichalcogenide absorbers

Plasma as the fourth state of matter has attracted great attention for material surface modification,which could induce changes in material microscopic factors,such as defects,phase transitions,crystallinity,and so on.However,the interactions among those microscopic factors and regulation mechanism of macroscopic properties have rarely been investigated.Two-dimensional(2D)transition metal dichalcogenide with tunable structure and phase is one of the most promising electromagnetic wave(EMW)absorbers,which provides a favorable platform for systematically studying the dynamic coupling of its microscopic factors.Herein,we constructed a NaBH_(4) solution-assisted Ar plasma method to modify the 2H-MoS_(2)and 1T-WS_(2)for exploring the regulation mechanism of microscopic factors.For MoS_(2)and WS_(2),NaBH_(4) solution-assisted Ar plasma treatment behaves with different effects on dielectric responses,realizing dynamic coupling of material microscopic factors to collaboratively promote EM losses coupling.Consequently,the MS-D3-0.5(MoS_(2),3 kV voltage,0.5 mol L^(-1)NaBH_(4) solution)displays an optimum effective absorption bandwidth of 8.01 GHz,which is 319.4%more than that of MS-raw sample.This study not only reveals the novel mechanism of plasma induced dynamic coupling of microscopic factors for EMW dissipation,but also presents a new method of plasma-dominated surface modification to optimize the EMW absorption performance.

Determination on Heavy Metals Content of Achyranthes bidentata Blume. through Inductively Coupled Plasma Mass Spectrometry (ICP-MS)

[Objective] The inductively coupled plasma mass spectrometry(ICP-MS)was constructed to determine the contents of lead,cadmium,mercury and arsenic in Archyranthes bidentata Blume.[Method]Under the optimum operation condition of ICP-MS,the samples were digested by microwave.The element 114In was taken as an internal standard element to compensate body effect and ICP-MS method was used to determine the contents of lead,cadmium,mercury and arsenic.[Result]For the determined elements,the correlation coefficient(r)of standard curve was over 0.9995 and recovery rate was from 96.7% to 106.4% while RSD was less than 11.2%.The result of determination showed that the heavy metal content in Archyranthes bidentata Blume.beyond standard was serious.[Conclusion]The constructed ICP-MS method with simple operation,rapid response,accuracy and high sensitivity in this experiment could be used for quality control of Chinese medicinal materials by detecting heavy metal contents in different Chinese medicinal materials from original places.

Vitrification of MSWI Fly Ash by Thermal Plasma Melting and Fate of Heavy Metals

Municipal solid waste incinerator （MSWI） fly ash with high basicity （about 1.68） was vitrified in a thermal plasma melting furnace system. Through the thermal plasma treatment, the vitrified product （slag） with amorphous dark glassy structure was obtained, and the leachability of hazardous metals in slag was significantly reduced. Meanwhile, it was found that the cooling rate affects significantly the immobility of heavy metals in slag. The mass distribution of heavy metals （Zn, Cd, Cr, Pb, As, Hg） was investigated in residual products （slag, secondary residues and flue gas）, in order to analyze the behavior of heavy metals in thermal plasma atmosphere. Heavy metal species with low boiling points accounting for the major fraction of their input-mass were adsorbed in secondary residues by pollution abatement devices, while those with high boiling points tended to be encapsulated in slag.

Impact of the Insulator on the Electric Field and Generation Characteristics of Vacuum Arc Metal Plasmas

The field electron emission plays a vital role in the process of vacuum discharge breakdown. The electric field strength at the cathode tip is significant to the generation char- acteristics of vacuum arc metal plasmas. To increase the field strength at the cathode tip, a coaxial electrode plasma source was employed with an insulator settled between the electrodes. The math expression of the field strength is derived based on the Gauss theory. The impact of the insulator on the electric field and parameters of plasmas were investigated by MAXWELL 3D simulation software and the Langmuir probe. In addition, a composite insulator was adopted to further strengthen the field strength. A series of experiments were performed to focus on the role of the composite insulator in detail. The experimental and simulation results indicate that, a reasonable layout of the insulator, especially the composite insulator, can effectively increase the field strength at the cathode tip and the plasma density.

Generation characteristics of a metal ion plasma jet in vacuum discharge

To improve the performance of a metal ion plasma jet in vacuum discharge, an anode-insulated cone-cylinder electrode with insulating sleeve is proposed in this paper. Discharge characteristics and generation characteristics of plasma of the electrode are investigated, effects of diameter of insulating sleeve, variety of cathode material and length of the insulating sleeve on characteristics of metal ion plasma jet are discussed. Results indicate that a directional and steady plasma jet is formed by using the novel electrode with insulating sleeve under high vacuum conditions. Moreover, the properties of metal ion plasma jet are improved by using the aluminum cathode and thin and long insulating sleeve. The study provides strong support for research of vacuum metal ion plasma thruster and ion implantation technology.

Trimming of a migrated metal stent for malignant colonic stricture using argon plasma coagulation

We report the first case of trimming of a migrated metal colonic stent for stent induced severe anorectal pain. We present a case of a 54-year-old female with history of metastatic colorectal carcinoma who had stent placement secondary to obstruction. Subsequent distal migration of the stent caused ulcerations into the rectal mucosa and excruciating anorectal pain. We used argon plasma coagulation (APC) to successfully trim the exposed distal portion of the metal stent and rat tooth forceps to retrieve the stent fragments. The use of APC for trimming metallic stents is an effective procedure that can be used to trim migrated rectal stents that result in significant rectal pain. To date, few studies have been published that use APC to trim metallic stents placed in the gastrointestinal tract. To the best of our knowledge, ours is the only known case in which the indication for stent trimming was severe stent induced rectal pain. The procedure resulted in complete relief of patient symptoms. Therefore, APC is a safe and effective way to trim colo-rectal stents to definitively relieve the symptom of stent induced rectal pain in patients who have experienced distal stent migration and mucosal ulceration.

Study of Spectral Character of Alkali Metals Using Microwave Plasma Torch Simultaneous Spectrometer

A microwave plasma torch （MPT） simultaneous spectrometer was used to study the spectral character and the matrix effect on alkali metal ions in solution. The main parameters were optimized. The microwave forward power was 100 W. The argon flow rate that was used to sustain the Ar-MPT included the flow rate of carrier gas and the flow rate of support gas, which were 0. 8 and 1.0 L/min, respectively. The HC1 concentration in the solution was 0.02 mol/L. The observation height was 9. 0 ram. The detection limits of Li, Na, K, Rb, and Cs were 0. 0003, 0. 0004, 0. 009, 0.07 and 2.4 mg/L, respectively, and the resuhs obtained by the Ar-MPT were compared with those obtained by argon inductively coupled plasma（Ar-ICP） and argon microwave induced plasma（Ar-MIP）. The interference effects of several matrix elements were also studied.

In vacuo XPS investigation of surface engineering for lithium metal anodes with plasma treatment

Lithium(Li)metal is an attractive anode material with high capacity(3860 mAh g^(−1))and low potential(−3.04 V vs.standard hydrogen electrode)that shows highly promising for applications requiring high energy density.However,the low electrochemical potential of Li metal makes it extremely reactive and inevitably forming a native oxidized layer in the ambient environment and repeatedly being consumed when exposed to liquid electrolytes.It is therefore beneficial to replace the poorly controlled native passivation layer with a tailored artificial SEI to improve interface management between Li and electrolyte and enhance the stability of Li metal battery.Here,we use an integrated glovebox-atomic layer deposition(ALD)-X-ray photoelectron spectroscopy(XPS)setup to in-situ investigating the pristine Li surface and the surface composition after Ar,H_(2)O_(2),N_(2)and NH_(3)plasma treatment processes.We find that the pristine Li foil is naturally being covered with a native oxidized layer,which is mainly composed of LiOH,Li_(2)O and Li_(2)CO_(3).These investigated plasmas can efficiently remove the oxidized layer from the Li metal surface,in which metallic Li surface is obtained after Ar or H2 plasma treatments,where Ar plasma is more efficient.While O_(2)plasma treatment produces a Li_(2)O layer,and N_(2)or NH_(3)plasma treatment leads to a Li3N(including a certain amount of LiON)layer on the Li surface.When employing the representative metallic Li(by Ar plasma treatment),Li_(2)O layer coated Li(by O_(2)plasma treatment)and Li3N layer coated Li(by N_(2)plasma treatment)foils as electrodes in symmetric Li metal batteries,the Li3N coated Li electrode exhibits much higher stability than that of metallic and Li_(2)O layer coated Li foils.Improved electrochemical performance has also been achieved in LiMn_(2)O_(4)(LMO)||Li full cells using Li anode with Li3N protective coating layer.Our work reveals the detailed process of surface engineering of Li metal anodes with plasma treatments by in vacuo XPS,which may also be extended to other gas-treatment or plasma-treatment for stabilization of high energy density Li metal anodes and other metal-based anodes.

Unveiling the Optimal Interfacial Synergy of Plasma-Modulated Trimetallic Mn-Ni-Co Phosphides:Tailoring Deposition Ratio for Complementary Water Splitting

Designing highly active,durable,and nonprecious metal-based bifunctional electrocatalysts for overall water electrolysis is of urgent scientific importance to realize the sustainable hydrogen production,which remains a grand challenge.Herein,an innovative approach is demonstrated to synthesize flower-like 3D homogenous trimetallic Mn,Ni,Co phosphide catalysts directly on nickel foam via electrodeposition followed by plasma phosphidation.The electrochemical activity of the catalysts with varying Mn:Ni:Co ratios is assessed to identify the optimal composition,demonstrating that the equimolar trimetallic phosphide yields an outstanding HER catalytic performance with a current density of 10 mA cm^(-2) at an ultra-low overpotential of~14 mV,outperforming the best reported electrocatalysts.This is asserted by the DFT calculations,revealing strong interaction of the metals and the P atom,resulting in enhanced water activation and optimized G_(H)^(*)values for the HER process.Moreover,this optimal composition appreciably catalyzes the OER by exposing more intrinsic active species in-situ formed on the catalyst surface during the OER.Therefore,the Mn_(1)-Ni_(1)-Co_(1)-P-(O)/NF catalyst exhibits a decreased overpotential of~289 mV at 10 mA cm^(-2).More importantly,the electrocatalyst sustains perfect durability up to 48 h at a current density of 10 mA cm^(-2) and continued 5000 cycling stability for both HER and OER.Meanwhile,the assembled MNC-P/NF||MNC-P/NF full water electrolyzer system attains an extremely low cell voltage of 1.48 V at 10 mA cm^(-2).Significantly,the robust stability of the overall system results in a remarkable current retention of~96%after a continuous 50-h run.Therefore,this study provides a facile design and a scalable construction of superb bifunctional ternary MNC-phosphide electrocatalysts for efficient electrochemical energy production systems.

High-Yield High-Efficiency Positron Generation in High-Z Metal Targets Irradiated by Laser Produced Electrons from Near-Critical Density Plasmas

An improved indirect scheme for laser positron generation is proposed. The positron yields in high-ZZ metal targets irradiated by laser produced electrons from near-critical density plasmas and underdense plasma are investigated numerically. It is found that the positron yield is mainly affected by the number of electrons of energies up to several hundreds of MeV. Using near-critical density targets for electron acceleration, the number of high energy electrons can be increased dramatically. Through start-to-end simulations, it is shown that up to 6.78×10106.78×1010 positrons can be generated with state-of-the-art Joule-class femtosecond laser systems.

Numerical simulation of temperature field in plasma-arc flexible forming of laminated-composite metal sheets

Flexible forming of laminated-composite metal sheets (LCMS) using plasma arc is a latest technique, which produces LCMS components by thermal stress without mould and external force. Considering that the controllable temperature field is the key during the forming process, a three-layer FEM model, based on the characteristics along LCMS thickness direction, was developed to study the variation rules of temperature field, which was verified robustness by experimental validation. Besides, the influences of process parameters such as plasma arc power, scanning speed and plasma arc diameter on LCMS temperature field were performed. The comparisons of LCMS with single layer metal sheet (SLMS) show the temperature difference of LCMS along thickness direction is smaller than that of SLMS, but the heat-affected zone of LCMS along X axis is wider than that of SLMS under the same process parameters.

Novel experimental strategy towards temperature inhomogeneity during spark plasma sintering of metallic glasses

Despite the importance of temperature distribution in spark plasma sintering of metallic glasses,its quantification has been experimentally laborious.This work proposes an experimental strategy to determine the sintering temperature by establishing a quantitative relationship between the temperature-thermal signal.We reproduced the thermal profiles of spark plasma sintering by isothermal annealing and found a correlation between annealing temperature and isothermal crystallization time.This strong correlation indicates the temperature-dependent structural evolution of glassy powders.Using isothermal crystallization time as the measuring gauge,we correlated the annealing temperature to the sintering temperature and obtained the sample temperature map.The sample temperature is at least 19C higher than the nominal temperature of 425C measured by the thermocouple.Meanwhile,the sample temperature shows a hump-shaped pattern closely correlated with the current density.The maximum temperature of 453C occurs on the sample/punches contact surfaces.Temperature heterogeneity within the sample induces diverse microstructures and porous structures.We elucidate that the temperature inhomogeneity is intrinsic,given the presence of contact interfaces.Contact resistances affect the current distribution and heat transfer,resulting in a larger temperature gradient than the traditional powder metallurgy process.

The Catalytic Effect of Metal Ions on the Degradation of 4-Chlorophenol Induced by an Aqueous Pulsed Discharge Plasma

The influence of metal ions, such as Fe^2＋, Fe^3＋, Cu^2＋ and Mn^2＋, on 4-CP degrada-tion was investigated in an aqueous pulsed discharge plasma system with or without the addition of a TiO2 photo-catalyst. From an analysis of the pseudo first-order rate constant （kcp） and energy efficiency （G50%） for 4-CP degradation, the experimental results show that the degrada- tion of 4-CP is much enhanced in the presence of ferrous ions at the optimal concentration of 0.2-0.8 mmol/L or 0.2 mmol/L in an aqueous pulsed discharge plasma without or with the TiO2 system, respectively, and the enhancement is ascribed to plasma induced Fenton and photo-Fenton reactions. Meanwhile, the rank of such metal ions for catalytic effect on 4-CP degradation was Fe^2＋〉 Fe^3＋ 〉 Cu^2＋ 〉 Mn^2＋ and Fe^2＋ 〉 Fe^3＋ 〉 Mn^2＋ 〉 Cu^2＋ for the former and the latter systems, respectively, and the reasons behind this were discussed through the analysis of active species, especially hydrogen peroxide.

Effects of Low Temperature Plasma on the Forms of Heavy Metals in Sludge

Low temperature plasma was used to treat sludge,and the effects of discharge time on the content of different forms of heavy metals in the sludge were studied. The results showed that Cu and Zn content in the domestic sludge could basically meet the requirements of GB 4284-2018,GB/T 23486-2009,CJ/T 362-2011 and CJ/T 309-2009. There were big differences between different forms of the heavy metals. According to the proportions of different forms of Cu in the sludge,different forms of Cu are arranged as follows: organic state > carbonate bound state> residual state > exchangeable state > iron-manganese oxidation state,and Cu mainly existed in an organic state. Various forms of Zn are arranged in order of the proportion as follows: iron-manganese oxidation state > residual state > carbonate bound state > exchangeable state > organic state,and Zn mainly existed in an iron-manganese oxidation state. After the treatment of sludge by low temperature plasma,the content of exchangeable Cu and Zn in the sludge increased,while the content and proportion of residual Cu and Zn all reduced.

Hydrogen cold plasma for synthesizing Pd/C catalysts: the effect of support-metal ion interaction

It has been found that cold plasma is a facile and environmentally benign method for synthesizing supported metal catalysts, and great efforts have been devoted to enlarging its applications. However, little work has been done to disclose the influence mechanism, which is significant for controllable synthesis. In this work, hydrogen cold plasma was adopted to synthesize a palladium catalyst supported on activated carbon （Pd/C-P） using HzPdC14 as a Pd precursor followed by calcination in hydrogen gas to remove the chlorine ions. The Pd/C-P catalyst was found to be made of larger Pd nanoparticles showing a decreased migration to the support outer surface than that prepared by the conventional thermal hydrogen reduction method （Pd/C-C）. Meanwhile, the pore diameter of the activated carbon support is small （,-~4 nm）. Therefore, Pd/C-P exhibits lower CO oxidation activity than Pd/C-C. It was proposed that the strong interaction between the activated carbon and PdC142-, and the enhanced metal-support interaction caused by hydrogen cold plasma reduction made it difficult for Pd nanoparticles to migrate to the support outer surface. The larger-sized Pd nanoparticles for Pd/C-P may be due to the Coulomb interaction resulting in the disturbance of the metal-support interaction. This work has important guiding significance for the controllable synthesis of supported metal catalysts by hydrogen cold plasma.

Study on the formation of arc plasma on the resistive wall liquid metal current limiter

Due to its significant attributes,the liquid metal current limiter(LMCL)is considered a new strategy for limiting short-circuit current in the power grid.A resistive wall liquid metal current limiter(RWLMCL)is designed to advance the starting current-limiting time.Experiments are performed to investigate the dynamic behaviors of liquid metal,and the influence of different currents on the liquid metal self-shrinkage effect is compared and analyzed.Furthermore,the liquid metal self-shrinkage effect is mathematically modeled,and the reason for the formation of arc plasma is obtained by simulation.The laws of arc plasma formation and the current transfer in the cavity are revealed,and the motion mechanisms are explained by physical principles.The simulations are in accordance with the test data.It is demonstrated that the sudden change of the current density at both ends of the wall causes the liquid metal to shrink and depress under the electromagnetic force,and the current starts to transfer from the liquid metal path to the wall resistance path.The RWLMCL can effectively advance the starting current-limiting time.

Powder metallurgical 3D nickel current collectors with plasma-induced Ni3N nanocoatings enabling long-life and dendrite-free lithium metal anode

Building three-dimensional(3D) current collectors is a promising strategy to surmount the bottlenecks of lithium metal anodes(LMAs), but the regulation methodology of a 3D current collector has seldom been considered comprehensively concerning both skeleton architectures and surface coatings. Herein, a robust porous 3D nickel skeleton(NS) with lithiophilic NiN nanocoatings(NiN@NS) is synthesized via an integrative route of powder metallurgy/plasma-enhanced nitridation technics. The facile powder metallurgical method facilitates the adjustment of NS architectures toward sufficient electrolyte adsorption and even current density distribution, while the followed plasma-enhanced chemical vapor deposition(PECVD) method can induce compact NiN nanocoatings on NS, which reduces the Li nucleation overpotential, accelerates the Li-ion transfer, and facilitates a highly reversible oriented texture of Li deposition morphology owing to the dense and homogenous deposition of Li into the pores. The optimized NiN@NS current collector shows a high averaged Coulombic efficiency(CE) of 98.8% over 350cycles, a prolonged lifespan of 1000 h(at 2 mA cm^(-2)) in symmetrical cells, together with the significant performance in full cells. The ingenious methodology reported in this work can also be broadly applicable for the controllable production of other 3D skeletons with nitride nanocoatings for various applications.

Physical Alloying of Plasma Metallization Carbide Nanocomposite Coating by Allotropic Carbon Nanostructures

The fundamental scientific problem for micro- and nano-electronics has been solved—methods for creating and investigating properties of physically doped materials with spatially inhomogeneous structure at the micro- and nano-meter scale have been developed. For the application of functional nanocomposite film coatings based on carbides of various transition metals structured by nanocarbon, for the first time in the world, we developed a new technique for their plasma deposition on a substrate without the use of reaction gases (hydrocarbons such as propane, acetylene, etc.). We have created nanostructured film materials, including those with increased strength and wear resistance, heterogeneous at the nanoscale, physically doped with nanostructures—quantum traps for free electrons. We learned how to simultaneously spray (in a plasma of a stationary magnetron discharge) carbides and graphite from a special mosaic target (carbide + carbon) made mechanically. As a result of such stationary sputtering of carbides and carbon, plasma nanostructured coatings were obtained from nanocarbides, metal nanocrystals and nanocarbon. Our design of such a target made it possible to intensively cool it in the magnetron body and spray its parts (carbide + carbon) simultaneously with a high power density of a constant plasma discharge—in the range of values from 40 W/cm2 to 125 W/cm2. Such sputtering with a change in the power or the initial relative surface areas of various parts of the mosaic target (carbon and carbide) made it possible to change the average density of carbide, metal and carbon in a nanostructured (nanocarbon and metal nanostructures) coating. The changed relative density of various components of the nanocomposite (nanostructures of carbide, metal, and carbon in the form of graphite) significantly affected the physical properties of the nanocomposite coating. The creating method of multiphase nanostructured composite coatings (based on carbides of transition metals) with high hardness of 30 GPa, a low coefficient of friction to dry 0.13 - 0.16, with high heat resistance up to 3000°C and thermal stability in the nanocrystalline state over 1200°C is developed. It is established that the presence of nanographite in the composite significantly improves the impact strength and extends the range of possible applications, compared with pure carbides. The solution to this problem will allow creating new nanostructured materials, investigating their various physical parameters with high accuracy, designing, manufacturing and operating devices with new technical and functional capabilities, including for the nuclear industry and rocket science.

Plasma-assisted Co/Zr-metal organic framework catalysis of CO_(2)hydrogenation:influence of Co precursors

In this study,Co/Zr-metal organic framework(MOF)precursors were obtained by a roomtemperature liquid-phase precipitation method and the equivalent-volume impregnation method,respectively,using a Zr-MOF as the support,and Co/Zr-MOF-M and Co/Zr-MOF-N catalysts were prepared after calcination in a hydrogen-argon mixture gases(VAr:V_(H_(2))=9:1)at 350℃for 2 h.The catalytic activities of the prepared samples for CO_(2)methanation under atmosphericpressure cold plasma were studied.The results showed that Co/Zr-MOF-M had a good synergistic effect with cold plasma.At a discharge power of 13.0 W,V_(H_(2)):VCO_(2)=4:1 and a gas flow rate of 30 ml·min^(-1),the CO_(2)conversion was 58.9%and the CH4 selectivity reached 94.7%,which was higher than for Co/Zr-MOF-N under plasma(CO_(2)conversion 24.8%,CH4 selectivity 9.8%).X-ray diffraction,scanning electron microscopy,transmission electron microscopy,N_(2)adsorption and desorption(Brunauer-Emmett-Teller)and x-ray photoelectron spectroscopy analysis results showed that Co/Zr-MOF-M and Co/Zr-MOF-N retained a good Zr-MOF framework structure,and the Co oxide was uniformly dispersed on the surface of the Zr-MOF.Compared with Co/Zr-MOF-N,the Co/Zr-MOF-M catalyst has a larger specific surface area and higher Co^(2+)/Cototaland Co/Zr ratios.Additionally,the Co oxide in Co/ZrMOF-M is distributed on the surface of the Zr-MOF in the form of porous particles,which may be the main reason why the catalytic activity of Co/Zr-MOF-M is higher than that of Co/ZrMOF-N.