A novel process was proposed for treating nickeliferous laterite ores with molten sodium hydroxide.The effect on silicon extraction caused by the factors,such as stirring speed,reaction temperature,particle size and N...A novel process was proposed for treating nickeliferous laterite ores with molten sodium hydroxide.The effect on silicon extraction caused by the factors,such as stirring speed,reaction temperature,particle size and NaOH-to-ore mass ratio,was investigated.The results show that increasing stirring speed,reaction temperature and NaOH-to-ore mass ratio while decreasing particle size increases silicon extraction rate.The desiliconization kinetics of nickeliferous laterite ores in molten sodium hydroxide system was described successfully by chemical reaction control model.The activation energy of the desiliconization process was found to be 44.01 kJ/mol,and the reaction rate based on a chemical reaction-controlled process can be expressed as:1-(1-α) 1/3 = 27.67exp[-44 010/(RT)]t.展开更多
HL-2A is a new middle-sized tokamak device with two closed divertors. In 2004 campaign siliconization as a wall condition has been first done on HL-2A since the starting operation of the device. By using sil-iconizati...HL-2A is a new middle-sized tokamak device with two closed divertors. In 2004 campaign siliconization as a wall condition has been first done on HL-2A since the starting operation of the device. By using sil-iconization we observed that impurity has been obviously decreased. The character of the siliconization and the effect of wall condition on plasma have been investigated as well as on the wall recycling.展开更多
The sputtering of impurities is caused by the interactions between plasma and the first wall, and the recycling of the gas affects the particle and energy transport of plasmas with a complicated mechanism in plasma op...The sputtering of impurities is caused by the interactions between plasma and the first wall, and the recycling of the gas affects the particle and energy transport of plasmas with a complicated mechanism in plasma operation. It is important for present tokarnaks to achieve a good confinement and high performance plasmas by means of controls of the vacuum condition, usage of low Z materials, control of the recycling of neutral particles and suppressions of the appearances and yield of impurities. For higher plasma parameters, some of the first wall of HL-2A is covered with graphite materials and carbon fiber tiles. Hence the studies on the in-situ coating application and development, and the interactions between the coating film and plasma are needed to effectively control the impurity, improve plasma confinement and achieve high performance plasma.展开更多
AIM:To investigate the effects of shortening the duration of silicone oil tamponade on retinal structure and function in patients undergoing silicone oil removal(SOR)after surgery for primary rhegmatogenous retinal de...AIM:To investigate the effects of shortening the duration of silicone oil tamponade on retinal structure and function in patients undergoing silicone oil removal(SOR)after surgery for primary rhegmatogenous retinal detachment(RRD).METHODS:A total of 58 eligible patients were enrolled and randomly assigned to two groups based on tamponade duration:the short-term group(30-45d)and the conventional group(≥90d).Comprehensive evaluations were performed before and after SOR,including slitlamp examination,best-corrected visual acuity(BCVA)measurement,intraocular pressure(IOP)testing,optical coherence tomography(OCT),optical coherence tomography angiography(OCTA),microperimetry,electroretinography(ERG),and visual evoked potential(VEP)assessment.RESULTS:A total of 33 patients(23 males and 10 females;33 eyes)were enrolled in the short-term SO tamponade group with mean age of 52.45±9.35y,and 25 patients(15 males and 10 females;25 eyes)were enrolled in the conventional SO tamponade group with mean age of 50.80±12.06y.Compared with the conventional group,the short-term silicone oil tamponade group had a significantly lower incidence of silicone oil emulsification and cataract progression,with no significant difference in retinal reattachment success rate.Structurally,short-term tamponade was associated with increased thickness of the retinal ganglion cell layer(RGCL)in the nasal and superior macular regions and improved recovery of superficial retinal vascular density in these areas.Functionally,the shortterm group showed better BCVA and retinal sensitivity both before and 1mo after SOR;additionally,the P100 amplitude in VEP tests was significantly increased in this group.CONCLUSION:Shortening the duration of silicone oil tamponade effectively reduces damage to retinal structure and function without compromising the success rate of retinal reattachment in patients with primary RRD.展开更多
The rapid expansion of the photovoltaic industry has generated heavily oxidized waste silicon(wSi),which hinders efficient recycling owing to its small particle size and uncontrolled surface oxidation.This study intro...The rapid expansion of the photovoltaic industry has generated heavily oxidized waste silicon(wSi),which hinders efficient recycling owing to its small particle size and uncontrolled surface oxidation.This study introduces a molten salt electrochemical strategy for converting photovoltaic wSi into NiSi_(2)-silicon nanorods(NiSi_(2)-SiNRs)as high-performance anode materials for lithium-ion batteries.A stable oxidized passivation layer is formed on the wSi surface via controlled oxidation,and further in situ generated highly active NiSi_(2) droplets.The molten salt electric field modulates the surface energy of silicon,while particle integration drives localized directional growth,enabling the self-assembly of NiSi_(2)-SiNRs composites.These NiSi_(2)-SiNRs anodes exhibit rapid ion transport and effective strain buffering.The high aspect ratio of SiNRs and the presence of retained NiSi_(2) facilitate both longitudinal and transverse Li^(+) diffusion.Owing to their robust structural design,the NiSi_(2)-SiNRs anode achieves an excellent initial Coulombic efficiency of 91.61%and retains 72.99%of its capacity after 800 cycles at 2 A·g^(−1).This study establishes a model system for investigating silicide/silicon interfaces in molten salt electrochemical synthesis and provides an effective strategy for upcycling photovoltaic wSi into high-performance lithium-ion battery anodes.展开更多
The differences in the competitive reactions of hydrogarnet and quicklime when reacting with titaniumcontaining and silicon-containing minerals during the Bayer digestion process were investigated.Thermodynamic analys...The differences in the competitive reactions of hydrogarnet and quicklime when reacting with titaniumcontaining and silicon-containing minerals during the Bayer digestion process were investigated.Thermodynamic analysis,artificial mineral experiments,and an evaluation of the digestion effect of natural diasporic bauxite were conducted.The results indicate that hydrogarnet shows a preferential reaction with anatase,and this preference becomes more pronounced as the silicon saturation coefficient increases.In contrast,quicklime participates in non-selective reactions with both anatase and desilication products(DSP).The preference of hydrogarnet for anatase significantly enhances the utilization efficiency of CaO in the high-temperature Bayer digestion process.展开更多
Desulfurization of CaO–Al_(2)O_(3) particles in molten steel was observed in situ using high-temperature confocal scanning laser microscopy.The effects of the aluminum and silicon contents of molten steel on desulfur...Desulfurization of CaO–Al_(2)O_(3) particles in molten steel was observed in situ using high-temperature confocal scanning laser microscopy.The effects of the aluminum and silicon contents of molten steel on desulfurization were analyzed.When the total aluminum content in the steel increased from 6 to 1100 ppm,the CaS content in CaO–Al_(2)O_(3) particles increased from 2.1wt%to 84.84wt%after the reaction for 90 s.Furthermore,when the silicon content in the steel increased from 0.01wt%to 2.20wt%,the CaS content in CaO–Al_(2)O_(3) particles increased from 1.53wt%to 79.01wt%after the reaction for 90 s.This indicates that the increase in the aluminum and silicon contents of the steel promoted the desulfurization of CaO–Al_(2)O_(3) particles.A kinetic model was established to predict the CaO–Al_(2)O_(3) particles composition,and the diffusion coefficient of sulfur in CaO–Al_(2)O_(3) particles was 9.375×10^(−10)m^(2)·s^(−1) at 1600℃,which provided a new method for the calculation of diffusion coefficient.展开更多
The electromagnetic wave absorption of silicon carbide nanowires is improved by their uniform and diverse cross-structures.This study introduces a sustainable and high value-added method for synthesizing silicon carbi...The electromagnetic wave absorption of silicon carbide nanowires is improved by their uniform and diverse cross-structures.This study introduces a sustainable and high value-added method for synthesizing silicon carbide nanowires using lignite and waste silicon powder as raw materials through carbothermal reduction.The staggered structure of nanowires promotes the creation of interfacial polarization,impedance matching,and multiple loss mechanisms,leading to enhanced electromagnetic absorption performance.The silicon carbide nanowires demonstrate outstanding electromagnetic absorption capabilities with the minimum reflection loss of-48.09 d B at10.08 GHz and an effective absorption bandwidth(the reflection loss less than-10 d B)ranging from 8.54 to 16.68 GHz with a thickness of 2.17 mm.This research presents an innovative approach for utilizing solid waste in an environmentally friendly manner to produce broadband silicon carbide composite absorbers.展开更多
The failure mechanisms and structural damage of SiC MOSFETs induced by heavy ion irradiation were demonstrated.The findings reveal three degradation modes,depending on the drain voltage.At a relatively low voltage,the...The failure mechanisms and structural damage of SiC MOSFETs induced by heavy ion irradiation were demonstrated.The findings reveal three degradation modes,depending on the drain voltage.At a relatively low voltage,the damage is triggered by the formation and activation of gate latent damage(LDs),with damage concentrated in the gate oxide.The second degradation mode involves permanent leakage current degradation,with damage progressively transitioning from the oxide to the SiC material as the drain voltage escalates.Ultimately,the device undergoes catastrophic burnout above certain voltages,characterized by the lattice temperature reaching the sublimation point of SiC,resulting in surface cavity and complete structural destruction.This paper presents a comprehensive investigation of SiC MOSFETs under heavy ion exposure,providing radiation resistance methods of SiC-based devices for aerospace applications.展开更多
Waste graphitization cathode carbon blocks are a type of hazardous solid waste generated during the aluminum electrolysis process,and their proper disposal is a key step in the resource utilization of discarded graphi...Waste graphitization cathode carbon blocks are a type of hazardous solid waste generated during the aluminum electrolysis process,and their proper disposal is a key step in the resource utilization of discarded graphite.This study utilizes the porous“defect advantage”of a cathode carbon block matrix to prepare silicon-doped and asphalt-coated detoxified and purified waste graphitization cathode carbon blocks for use as high-performance silicon/carbon composite anode materials.The results show that the uniformly silicondoped silicon/carbon composite material features a unique amorphous carbon-encapsulated“locked silicon”structure,which effectively addresses issues such as cathode volume expansion,excessive growth of the solid electrolyte interphase(SEI)film,and poor electrical contact between active materials.Consequently,electrochemical performance is enhanced.After assembly in a half-cell,the PSCC/10%Si@C(purified waste graphitization cathode carbon/10%Si@C)material exhibits optimal electrochemical stability,with an initial charging specific capacity of 514.5 mAh/g at 0.1 C(1 C=170 mA/g)and a capacity retention rate of 95.1%after 100 cycles.At a charge rate of 2.0 C,a specific capacity of 216.9 mAh/g is achieved.This technology provides a new pathway for the economical and high-value utilization of waste cathode carbon blocks and the development of low-cost,high-performance anode materials.展开更多
To fully utilize the resources provided by optical fiber networks,a cross-band quantum light source generating photon pairs,where one photon in a pair is at C band and the other is at O band,is proposed in this work.T...To fully utilize the resources provided by optical fiber networks,a cross-band quantum light source generating photon pairs,where one photon in a pair is at C band and the other is at O band,is proposed in this work.This source is based on spontaneous four-wave mixing(SFWM)in a piece of shallow-ridge silicon waveguide.Theoretical analysis shows that the waveguide dispersion could be tailored by adjusting the ridge width,enabling broadband photon pair generation by SFWM across C band and O band.The spontaneous Raman scattering(SpRS)in silicon waveguides is also investigated experimentally.It shows that there are two regions in the spectrum of generated photons from SpRS,which could be used to achieve cross-band photon pair generation.A chip of shallow-ridge silicon waveguide samples with different ridge widths has been fabricated,through which cross-band photon pair generation is demonstrated experimentally.The experimental results show that the source can be achieved using dispersion-optimized shallow-ridge silicon waveguides.This cross-band quantum light source provides a way to develop new fiber-based quantum communication functions utilizing both C band and O band and extends applications of quantum networks.展开更多
Superfine spherical fire-extinguishing powder, ammonium dihydrogen phosphate （ADP, NH4 H2 PO4）, was prepared by spray drying and modified in situ with methyl hydrogen silicone oil （MHSO） emulsion and the fluorinat...Superfine spherical fire-extinguishing powder, ammonium dihydrogen phosphate （ADP, NH4 H2 PO4）, was prepared by spray drying and modified in situ with methyl hydrogen silicone oil （MHSO） emulsion and the fluorinated surfactant FK-510. The influences of the MHSO mass ratio on the hydrophobicity, sur- face composition, surface morphology, dispersion and particle-size distribution of the NH4H2PO4 were studied, and the influence of the drying air temperature on the decomposition of the NH4H2PO4 was also researched. The results indicate that the MHSO and FK-510 congregate on the particle surfaces and then form a hydrophobic shell. This shell improves the particle hydrophobicity and leads to a fine dispersion of the particles. During the process of preparing the precursor solution, 3 wt% （based on the weight of NH4H2 PO4 ） was chosen as the optimum value of the MHSO mass ratio. During the spray drying, a low abso- lute humidity of the air should be maintained, and it is very important to keep the exit-air temperature below 100℃ to avoid decomposition.展开更多
Silicon stands as a key anode material in lithium-ion battery ascribing to its high energy density.Nevertheless,the poor rate performance and limited cycling life remain unresolved through conventional approaches that...Silicon stands as a key anode material in lithium-ion battery ascribing to its high energy density.Nevertheless,the poor rate performance and limited cycling life remain unresolved through conventional approaches that involve carbon composites or nanostructures,primarily due to the un-controllable effects arising from the substantial formation of a solid electrolyte interphase(SEI)during the cycling.Here,an ultra-thin and homogeneous Ti doping alumina oxide catalytic interface is meticulously applied on the porous Si through a synergistic etching and hydrolysis process.This defect-rich oxide interface promotes a selective adsorption of fluoroethylene carbonate,leading to a catalytic reaction that can be aptly described as“molecular concentration-in situ conversion”.The resultant inorganic-rich SEI layer is electrochemical stable and favors ion-transport,particularly at high-rate cycling and high temperature.The robustly shielded porous Si,with a large surface area,achieves a high initial Coulombic efficiency of 84.7%and delivers exceptional high-rate performance at 25 A g^(−1)(692 mAh g^(−1))and a high Coulombic efficiency of 99.7%over 1000 cycles.The robust SEI constructed through a precious catalytic layer promises significant advantages for the fast development of silicon-based anode in fast-charging batteries.展开更多
Coastal wetlands face dual pressures from high salinity and heavy metal pollution,presenting significant ecological challenges.Halophytes like Sesuvium portulacastrum possess unique physiological mechanisms to mitigat...Coastal wetlands face dual pressures from high salinity and heavy metal pollution,presenting significant ecological challenges.Halophytes like Sesuvium portulacastrum possess unique physiological mechanisms to mitigate metal toxicity.This study investigates how silicon (Si) availability influences the accumulation of copper (Cu) and cadmium (Cd) in S.portulacastrum.Our results show that Si supplementation at environmentally relevant levels significantly increases Cu and Cd concentrations in the roots,while simultaneously reducing the root-to-shoot translocation of these metals.In situ non-invasive micro-testing revealed decreased metal efflux from the xylem,indicating an enhanced retention of metals in the roots.Furthermore,analyses using X-ray photoelectron spectroscopy and atomic force microscopy demonstrated a higher density of oxygen-containing functional groups and SiO-on the extracellular matrix of Si-enriched roots.This structural transformation resulted in a significant reduction in root surface potential,facilitating greater metal ion attraction and uptake.The findings from this study provide critical insights into the mechanisms by which Si availability regulates metal accumulation in halophytes,suggesting potential strategies for mitigating metal pollution in coastal wetland ecosystems.展开更多
Silicon‐based anode materials have garnered considerable attention in lithium‐ion batteries(LIBs)due to their exceptionally high theoretical capacity and energy density.However,intrinsic challenges,such as significa...Silicon‐based anode materials have garnered considerable attention in lithium‐ion batteries(LIBs)due to their exceptionally high theoretical capacity and energy density.However,intrinsic challenges,such as significant volumetric expansion and the consequent degradation in cycling stability,severely hinder their practical application.As a result,development of silicon anodes that can effectively mitigate volumetric expansions,enhance cycling durability,and improve rate performance has emerged as a critical research focus.However,due to neglect of“size effects”,the modification strategy of silicon‐based electrodes lacks systematic,scientific,and comprehensive guidance.Herein,this review starts from the“size effect”of silicon‐based materials,and reveals in depth the different failure mechanisms of nano‐silicon(Si NPs)and micro‐silicon(μSi).Furthermore,this review provides targeted classification of modification strategies for Si NPs andμSi,and reviews comprehensively,in detail,and in depth the latest research progress on silicon‐based materials.In addition,the review also comprehensively summarizes the cutting‐edge dynamics of matching silicon‐based electrodes with solid electrolytes to construct high‐energy LIBs.It is hoped that this review can provide comprehensive and systematic scientific guidance for modification strategies of silicon‐based electrodes,which is of great significance for promoting the industrialization process of silicon‐based electrodes in high‐energy LIBs.展开更多
Silicon nanowires(SiNWs)have been used in a wide variety of applications over the past few decades due to their excellent material properties.The only drawback is the high production cost of SiNWs.The preparation of S...Silicon nanowires(SiNWs)have been used in a wide variety of applications over the past few decades due to their excellent material properties.The only drawback is the high production cost of SiNWs.The preparation of SiNWs from photovoltaic waste silicon(WSi)powders,which are high-volume industrial wastes,not only avoids the secondary energy consumption and environmental pollution caused by complicated recycling methods,but also realizes its high-value utilization.Herein,we present a method to rapidly convert photovoltaic WSi powders into SiNWs products.The flash heating and quenching provided by carbothermal shock induce the production of free silicon atoms from the WSi powders,which are rapidly reorganized and assembled into SiNWs during the vapor-phase process.This method allows for the one-step composite of SiNWs and carbon cloth(CC)and the formation of SiC at the interface of the silicon(Si)and carbon(C)contact to create a stable chemical connection.The obtained SiNWs-CC(SiNWs@CC)composites can be directly used as lithium anodes,exhibiting high initial coulombic efficiency(86.4%)and stable cycling specific capacity(2437.4 mA h g^(-1)at 0.5 A g^(-1)after 165 cycles).In addition,various SiNWs@C composite electrodes are easily prepared using this method.展开更多
This study addresses the challenge of real-time resistivity gradient measurement in the Czochralski(CZ)silicon production process.Due to the inability to directly measure this parameter,we propose a Long Short-Term Me...This study addresses the challenge of real-time resistivity gradient measurement in the Czochralski(CZ)silicon production process.Due to the inability to directly measure this parameter,we propose a Long Short-Term Memory soft-sensing model based on Convolutional Neural Network(CNN)and attention mechanism(CNN-ALSTM)that enhances traditional LSTM by integrating CNN and attention mechanism to overcome time lag variations during silicon pulling.The CNN module extracts spatial features from multi-source sensor data,while the attention-enhanced LSTM(ALSTM)dynamically adjusts historical parameter weights,enabling accurate resistivity gradient prediction.Experiments with real production data show that CNN-ALSTM outperforms SVR,FNN,RNN,XGBoost,and GRU,improving prediction accuracy by 11.76%,16.67%,21.05%,30.23%,and 9.09%,respectively.This soft-sensing approach enhances real-time monitoring and optimization of monocrystalline silicon growth.展开更多
To address the increasing demand for massive data storage and processing,brain-inspired neuromorphic comput-ing systems based on artificial synaptic devices have been actively developed in recent years.Among the vario...To address the increasing demand for massive data storage and processing,brain-inspired neuromorphic comput-ing systems based on artificial synaptic devices have been actively developed in recent years.Among the various materials inves-tigated for the fabrication of synaptic devices,silicon carbide(SiC)has emerged as a preferred choices due to its high electron mobility,superior thermal conductivity,and excellent thermal stability,which exhibits promising potential for neuromorphic applications in harsh environments.In this review,the recent progress in SiC-based synaptic devices is summarized.Firstly,an in-depth discussion is conducted regarding the categories,working mechanisms,and structural designs of these devices.Subse-quently,several application scenarios for SiC-based synaptic devices are presented.Finally,a few perspectives and directions for their future development are outlined.展开更多
Silicon is believed to be a critical anode material for approaching the roadmap of lithium-ion batteries due to its high specific capacity. But this aim has been hindered by the quick capacity fading of its electrodes...Silicon is believed to be a critical anode material for approaching the roadmap of lithium-ion batteries due to its high specific capacity. But this aim has been hindered by the quick capacity fading of its electrodes during repeated charge–discharge cycles. In this work, a “soft-hard”double-layer coating has been proposed and carried out on ball-milled silicon particles. It is composed of inside conductive pathway and outside elastic coating, which is achieved by decomposing a conductive graphite layer on the silicon surface and further coating it with a polymer layer.The incorporation of the second elastic coating on the inside carbon coating enables silicon particles strongly interacted with binders, thereby making the electrodes displaying an obviously improved cycling stability. As-obtained double-coated silicon anodes deliver a reversible capacity of 2280 m Ah g^(-1)at the voltage of 0.05–2 V, and maintains over 1763 mAh g^(-1)after 50 cycles. The double-layer coating does not crack after the repeated cycling, critical for the robust performance of the electrodes. In addition, as-obtained silicon particles are mixed with commercial graphite to make actual anodes for lithium-ion batteries. A capacity of 714 mAh g^(-1)has been achieved based on the total mass of the electrodes containing 10 wt.% double-coated silicon particles. Compared with traditional carbon coating or polymeric coating, the double-coating electrodes display a much better performance. Therefore, the double-coating strategy can give inspiration for better design and synthesis of silicon anodes, as well as other battery materials.展开更多
Purpose–The brake pipe system was an essential braking component of the railway freight trains,but the existing E-type sealing rings had problems such as insufficient low-temperature resistance,poor heat stability an...Purpose–The brake pipe system was an essential braking component of the railway freight trains,but the existing E-type sealing rings had problems such as insufficient low-temperature resistance,poor heat stability and short service life.To address these issues,low-phenyl silicone rubber was prepared and tested,and the finite element analysis and experimental studies on the sealing performance of its sealing rings were carried out.Design/methodology/approach–The low-temperature resistance and thermal stability of the prepared lowphenyl silicone rubber were studied using low-temperature tensile testing,differential scanning calorimetry,dynamic thermomechanical analysis and thermogravimetric analysis.The sealing performance of the lowphenyl silicone rubber sealing ring was studied by using finite element analysis software abaqus and experiments.Findings–The prepared low-phenyl silicone rubber sealing ring possessed excellent low-temperature resistance and thermal stability.According to the finite element analysis results,the finish of the flange sealing surface and groove outer edge should be ensured,and extrusion damage should be avoided.The sealing rings were more susceptible to damage in high compression ratio and/or low-temperature environments.When the sealing effect was ensured,a small compression ratio should be selected,and rubbers with hardness and elasticity less affected by temperature should be selected.The prepared low-phenyl silicone rubber sealing ring had zero leakage at both room temperature(RT)and�508C.Originality/value–The innovation of this study is that it provides valuable data and experience for the future development of the sealing rings used in the brake pipe flange joints of the railway freight cars in China.展开更多
基金Project(2007CB613603)supported by the National Basic Research Program of China
文摘A novel process was proposed for treating nickeliferous laterite ores with molten sodium hydroxide.The effect on silicon extraction caused by the factors,such as stirring speed,reaction temperature,particle size and NaOH-to-ore mass ratio,was investigated.The results show that increasing stirring speed,reaction temperature and NaOH-to-ore mass ratio while decreasing particle size increases silicon extraction rate.The desiliconization kinetics of nickeliferous laterite ores in molten sodium hydroxide system was described successfully by chemical reaction control model.The activation energy of the desiliconization process was found to be 44.01 kJ/mol,and the reaction rate based on a chemical reaction-controlled process can be expressed as:1-(1-α) 1/3 = 27.67exp[-44 010/(RT)]t.
文摘HL-2A is a new middle-sized tokamak device with two closed divertors. In 2004 campaign siliconization as a wall condition has been first done on HL-2A since the starting operation of the device. By using sil-iconization we observed that impurity has been obviously decreased. The character of the siliconization and the effect of wall condition on plasma have been investigated as well as on the wall recycling.
文摘The sputtering of impurities is caused by the interactions between plasma and the first wall, and the recycling of the gas affects the particle and energy transport of plasmas with a complicated mechanism in plasma operation. It is important for present tokarnaks to achieve a good confinement and high performance plasmas by means of controls of the vacuum condition, usage of low Z materials, control of the recycling of neutral particles and suppressions of the appearances and yield of impurities. For higher plasma parameters, some of the first wall of HL-2A is covered with graphite materials and carbon fiber tiles. Hence the studies on the in-situ coating application and development, and the interactions between the coating film and plasma are needed to effectively control the impurity, improve plasma confinement and achieve high performance plasma.
基金Supported by the Key Science&Technology Project of Guangzhou(No.202103000045)the National Natural Science Foundation of China(No.82070972,No.82271093).
文摘AIM:To investigate the effects of shortening the duration of silicone oil tamponade on retinal structure and function in patients undergoing silicone oil removal(SOR)after surgery for primary rhegmatogenous retinal detachment(RRD).METHODS:A total of 58 eligible patients were enrolled and randomly assigned to two groups based on tamponade duration:the short-term group(30-45d)and the conventional group(≥90d).Comprehensive evaluations were performed before and after SOR,including slitlamp examination,best-corrected visual acuity(BCVA)measurement,intraocular pressure(IOP)testing,optical coherence tomography(OCT),optical coherence tomography angiography(OCTA),microperimetry,electroretinography(ERG),and visual evoked potential(VEP)assessment.RESULTS:A total of 33 patients(23 males and 10 females;33 eyes)were enrolled in the short-term SO tamponade group with mean age of 52.45±9.35y,and 25 patients(15 males and 10 females;25 eyes)were enrolled in the conventional SO tamponade group with mean age of 50.80±12.06y.Compared with the conventional group,the short-term silicone oil tamponade group had a significantly lower incidence of silicone oil emulsification and cataract progression,with no significant difference in retinal reattachment success rate.Structurally,short-term tamponade was associated with increased thickness of the retinal ganglion cell layer(RGCL)in the nasal and superior macular regions and improved recovery of superficial retinal vascular density in these areas.Functionally,the shortterm group showed better BCVA and retinal sensitivity both before and 1mo after SOR;additionally,the P100 amplitude in VEP tests was significantly increased in this group.CONCLUSION:Shortening the duration of silicone oil tamponade effectively reduces damage to retinal structure and function without compromising the success rate of retinal reattachment in patients with primary RRD.
基金supported by the Yunnan Province Basic Research General Program,China(No.202201BE070001-002)the Major Science and Technology Projects in Yunnan Province,China(No.202402AF 080005).
文摘The rapid expansion of the photovoltaic industry has generated heavily oxidized waste silicon(wSi),which hinders efficient recycling owing to its small particle size and uncontrolled surface oxidation.This study introduces a molten salt electrochemical strategy for converting photovoltaic wSi into NiSi_(2)-silicon nanorods(NiSi_(2)-SiNRs)as high-performance anode materials for lithium-ion batteries.A stable oxidized passivation layer is formed on the wSi surface via controlled oxidation,and further in situ generated highly active NiSi_(2) droplets.The molten salt electric field modulates the surface energy of silicon,while particle integration drives localized directional growth,enabling the self-assembly of NiSi_(2)-SiNRs composites.These NiSi_(2)-SiNRs anodes exhibit rapid ion transport and effective strain buffering.The high aspect ratio of SiNRs and the presence of retained NiSi_(2) facilitate both longitudinal and transverse Li^(+) diffusion.Owing to their robust structural design,the NiSi_(2)-SiNRs anode achieves an excellent initial Coulombic efficiency of 91.61%and retains 72.99%of its capacity after 800 cycles at 2 A·g^(−1).This study establishes a model system for investigating silicide/silicon interfaces in molten salt electrochemical synthesis and provides an effective strategy for upcycling photovoltaic wSi into high-performance lithium-ion battery anodes.
基金the financial support from the Natural Science Foundation of Hunan Province,China(No.2022JJ40616)。
文摘The differences in the competitive reactions of hydrogarnet and quicklime when reacting with titaniumcontaining and silicon-containing minerals during the Bayer digestion process were investigated.Thermodynamic analysis,artificial mineral experiments,and an evaluation of the digestion effect of natural diasporic bauxite were conducted.The results indicate that hydrogarnet shows a preferential reaction with anatase,and this preference becomes more pronounced as the silicon saturation coefficient increases.In contrast,quicklime participates in non-selective reactions with both anatase and desilication products(DSP).The preference of hydrogarnet for anatase significantly enhances the utilization efficiency of CaO in the high-temperature Bayer digestion process.
基金supported by the National Key R&D Program of China(No.2023YFB3709900)the National Nature Science Foundation of China(No.U22A20171)+1 种基金the China Baowu Low Carbon Metallurgy Innovation Foundation(No.BWLCF202315)the High Steel Center(HSC)at North China University of Technology and University of Science and Technology Beijing,China.
文摘Desulfurization of CaO–Al_(2)O_(3) particles in molten steel was observed in situ using high-temperature confocal scanning laser microscopy.The effects of the aluminum and silicon contents of molten steel on desulfurization were analyzed.When the total aluminum content in the steel increased from 6 to 1100 ppm,the CaS content in CaO–Al_(2)O_(3) particles increased from 2.1wt%to 84.84wt%after the reaction for 90 s.Furthermore,when the silicon content in the steel increased from 0.01wt%to 2.20wt%,the CaS content in CaO–Al_(2)O_(3) particles increased from 1.53wt%to 79.01wt%after the reaction for 90 s.This indicates that the increase in the aluminum and silicon contents of the steel promoted the desulfurization of CaO–Al_(2)O_(3) particles.A kinetic model was established to predict the CaO–Al_(2)O_(3) particles composition,and the diffusion coefficient of sulfur in CaO–Al_(2)O_(3) particles was 9.375×10^(−10)m^(2)·s^(−1) at 1600℃,which provided a new method for the calculation of diffusion coefficient.
基金supported by the National Natural Science Foundation of China(No.52436008)the Inner Mongolia Science and Technology Projects,China(Nos.JMRHZX20210003 and 2023YFCY0009)+3 种基金the Huaneng Group Co Ltd.,China(No.HNKJ23-H50)the National Natural Science Foundation of China(No.22408044)the China Postdoctoral Science Foundation(No.2024M761877)the National Key R&D Program of China(No.SQ2024YFD2200039)。
文摘The electromagnetic wave absorption of silicon carbide nanowires is improved by their uniform and diverse cross-structures.This study introduces a sustainable and high value-added method for synthesizing silicon carbide nanowires using lignite and waste silicon powder as raw materials through carbothermal reduction.The staggered structure of nanowires promotes the creation of interfacial polarization,impedance matching,and multiple loss mechanisms,leading to enhanced electromagnetic absorption performance.The silicon carbide nanowires demonstrate outstanding electromagnetic absorption capabilities with the minimum reflection loss of-48.09 d B at10.08 GHz and an effective absorption bandwidth(the reflection loss less than-10 d B)ranging from 8.54 to 16.68 GHz with a thickness of 2.17 mm.This research presents an innovative approach for utilizing solid waste in an environmentally friendly manner to produce broadband silicon carbide composite absorbers.
基金Project supported by the National Key Research and Development Program of China(Grant No.2023YFA1609000)the National Natural Science Foundation of China(Grant Nos.U2341222,U2441248,12275061,and 12075069)。
文摘The failure mechanisms and structural damage of SiC MOSFETs induced by heavy ion irradiation were demonstrated.The findings reveal three degradation modes,depending on the drain voltage.At a relatively low voltage,the damage is triggered by the formation and activation of gate latent damage(LDs),with damage concentrated in the gate oxide.The second degradation mode involves permanent leakage current degradation,with damage progressively transitioning from the oxide to the SiC material as the drain voltage escalates.Ultimately,the device undergoes catastrophic burnout above certain voltages,characterized by the lattice temperature reaching the sublimation point of SiC,resulting in surface cavity and complete structural destruction.This paper presents a comprehensive investigation of SiC MOSFETs under heavy ion exposure,providing radiation resistance methods of SiC-based devices for aerospace applications.
基金supported by the National Natural Science Foundation of China(No.52274346).
文摘Waste graphitization cathode carbon blocks are a type of hazardous solid waste generated during the aluminum electrolysis process,and their proper disposal is a key step in the resource utilization of discarded graphite.This study utilizes the porous“defect advantage”of a cathode carbon block matrix to prepare silicon-doped and asphalt-coated detoxified and purified waste graphitization cathode carbon blocks for use as high-performance silicon/carbon composite anode materials.The results show that the uniformly silicondoped silicon/carbon composite material features a unique amorphous carbon-encapsulated“locked silicon”structure,which effectively addresses issues such as cathode volume expansion,excessive growth of the solid electrolyte interphase(SEI)film,and poor electrical contact between active materials.Consequently,electrochemical performance is enhanced.After assembly in a half-cell,the PSCC/10%Si@C(purified waste graphitization cathode carbon/10%Si@C)material exhibits optimal electrochemical stability,with an initial charging specific capacity of 514.5 mAh/g at 0.1 C(1 C=170 mA/g)and a capacity retention rate of 95.1%after 100 cycles.At a charge rate of 2.0 C,a specific capacity of 216.9 mAh/g is achieved.This technology provides a new pathway for the economical and high-value utilization of waste cathode carbon blocks and the development of low-cost,high-performance anode materials.
基金supported by the Quantum Science and Technology-National Science and Technology Major Project (Grant No.2024ZD0302502 for WZ)the National Natural Science Foundation of China(Grant No.92365210 for WZ)+1 种基金Tsinghua Initiative Scientific Research Program (for WZ)the project of Tsinghua University-Zhuhai Huafa Industrial Share Company Joint Institute for Architecture Optoelectronic Technologies (JIAOT,for YH)。
文摘To fully utilize the resources provided by optical fiber networks,a cross-band quantum light source generating photon pairs,where one photon in a pair is at C band and the other is at O band,is proposed in this work.This source is based on spontaneous four-wave mixing(SFWM)in a piece of shallow-ridge silicon waveguide.Theoretical analysis shows that the waveguide dispersion could be tailored by adjusting the ridge width,enabling broadband photon pair generation by SFWM across C band and O band.The spontaneous Raman scattering(SpRS)in silicon waveguides is also investigated experimentally.It shows that there are two regions in the spectrum of generated photons from SpRS,which could be used to achieve cross-band photon pair generation.A chip of shallow-ridge silicon waveguide samples with different ridge widths has been fabricated,through which cross-band photon pair generation is demonstrated experimentally.The experimental results show that the source can be achieved using dispersion-optimized shallow-ridge silicon waveguides.This cross-band quantum light source provides a way to develop new fiber-based quantum communication functions utilizing both C band and O band and extends applications of quantum networks.
文摘Superfine spherical fire-extinguishing powder, ammonium dihydrogen phosphate （ADP, NH4 H2 PO4）, was prepared by spray drying and modified in situ with methyl hydrogen silicone oil （MHSO） emulsion and the fluorinated surfactant FK-510. The influences of the MHSO mass ratio on the hydrophobicity, sur- face composition, surface morphology, dispersion and particle-size distribution of the NH4H2PO4 were studied, and the influence of the drying air temperature on the decomposition of the NH4H2PO4 was also researched. The results indicate that the MHSO and FK-510 congregate on the particle surfaces and then form a hydrophobic shell. This shell improves the particle hydrophobicity and leads to a fine dispersion of the particles. During the process of preparing the precursor solution, 3 wt% （based on the weight of NH4H2 PO4 ） was chosen as the optimum value of the MHSO mass ratio. During the spray drying, a low abso- lute humidity of the air should be maintained, and it is very important to keep the exit-air temperature below 100℃ to avoid decomposition.
基金the National Key R&D Plan of the Ministry of Science and Technology of China(2022YFE0122400)National Natural Science Foundation of China(52002238,22102207)+1 种基金Science and Technology Commission of Shanghai Municipality(22ZR1423800,21ZR1465200,23ZR1423600)Shanghai Municipal Education Commission and the NSRF via the Program Management Unit for Human Resources&Institutional Development,Research and Innovation(B49G680115).
文摘Silicon stands as a key anode material in lithium-ion battery ascribing to its high energy density.Nevertheless,the poor rate performance and limited cycling life remain unresolved through conventional approaches that involve carbon composites or nanostructures,primarily due to the un-controllable effects arising from the substantial formation of a solid electrolyte interphase(SEI)during the cycling.Here,an ultra-thin and homogeneous Ti doping alumina oxide catalytic interface is meticulously applied on the porous Si through a synergistic etching and hydrolysis process.This defect-rich oxide interface promotes a selective adsorption of fluoroethylene carbonate,leading to a catalytic reaction that can be aptly described as“molecular concentration-in situ conversion”.The resultant inorganic-rich SEI layer is electrochemical stable and favors ion-transport,particularly at high-rate cycling and high temperature.The robustly shielded porous Si,with a large surface area,achieves a high initial Coulombic efficiency of 84.7%and delivers exceptional high-rate performance at 25 A g^(−1)(692 mAh g^(−1))and a high Coulombic efficiency of 99.7%over 1000 cycles.The robust SEI constructed through a precious catalytic layer promises significant advantages for the fast development of silicon-based anode in fast-charging batteries.
基金supported by the National Natural Science Foundation of China (Nos.42376152 and 42306155)Guangdong Major Project of Basic and Applied Basic Research(No.2023B0303000017)+2 种基金the Special Program of Key Sectors in Guangdong Universities (No.2022ZDZX4040)the Innovation Team Project of Universities in Guangdong Province (No.2023KCXTD028)Guangxi Key Laboratory of Marine Environmental Change and Disaster in Beibu Gulf,Beibu Gulf University (No.2022KF007)。
文摘Coastal wetlands face dual pressures from high salinity and heavy metal pollution,presenting significant ecological challenges.Halophytes like Sesuvium portulacastrum possess unique physiological mechanisms to mitigate metal toxicity.This study investigates how silicon (Si) availability influences the accumulation of copper (Cu) and cadmium (Cd) in S.portulacastrum.Our results show that Si supplementation at environmentally relevant levels significantly increases Cu and Cd concentrations in the roots,while simultaneously reducing the root-to-shoot translocation of these metals.In situ non-invasive micro-testing revealed decreased metal efflux from the xylem,indicating an enhanced retention of metals in the roots.Furthermore,analyses using X-ray photoelectron spectroscopy and atomic force microscopy demonstrated a higher density of oxygen-containing functional groups and SiO-on the extracellular matrix of Si-enriched roots.This structural transformation resulted in a significant reduction in root surface potential,facilitating greater metal ion attraction and uptake.The findings from this study provide critical insights into the mechanisms by which Si availability regulates metal accumulation in halophytes,suggesting potential strategies for mitigating metal pollution in coastal wetland ecosystems.
基金supported by The Key R&D Program of Heilongjiang province(2023ZX04A01)The Key Project of Chongqing Technology Innovation and Application Development(2022TIAD‐DEX0024,2023TIAD‐KPX0007)+2 种基金The National Key R&D Program of China(2021YFC2902905)the Beijing Nova Program,the Chongqing Outstanding Youth Fund(2022NSCQ‐JQX3895)the National Natural Science Foundation of China(22109010).
文摘Silicon‐based anode materials have garnered considerable attention in lithium‐ion batteries(LIBs)due to their exceptionally high theoretical capacity and energy density.However,intrinsic challenges,such as significant volumetric expansion and the consequent degradation in cycling stability,severely hinder their practical application.As a result,development of silicon anodes that can effectively mitigate volumetric expansions,enhance cycling durability,and improve rate performance has emerged as a critical research focus.However,due to neglect of“size effects”,the modification strategy of silicon‐based electrodes lacks systematic,scientific,and comprehensive guidance.Herein,this review starts from the“size effect”of silicon‐based materials,and reveals in depth the different failure mechanisms of nano‐silicon(Si NPs)and micro‐silicon(μSi).Furthermore,this review provides targeted classification of modification strategies for Si NPs andμSi,and reviews comprehensively,in detail,and in depth the latest research progress on silicon‐based materials.In addition,the review also comprehensively summarizes the cutting‐edge dynamics of matching silicon‐based electrodes with solid electrolytes to construct high‐energy LIBs.It is hoped that this review can provide comprehensive and systematic scientific guidance for modification strategies of silicon‐based electrodes,which is of great significance for promoting the industrialization process of silicon‐based electrodes in high‐energy LIBs.
基金partially funded by the National Natural Science Foundation of China(52074255,52274412)。
文摘Silicon nanowires(SiNWs)have been used in a wide variety of applications over the past few decades due to their excellent material properties.The only drawback is the high production cost of SiNWs.The preparation of SiNWs from photovoltaic waste silicon(WSi)powders,which are high-volume industrial wastes,not only avoids the secondary energy consumption and environmental pollution caused by complicated recycling methods,but also realizes its high-value utilization.Herein,we present a method to rapidly convert photovoltaic WSi powders into SiNWs products.The flash heating and quenching provided by carbothermal shock induce the production of free silicon atoms from the WSi powders,which are rapidly reorganized and assembled into SiNWs during the vapor-phase process.This method allows for the one-step composite of SiNWs and carbon cloth(CC)and the formation of SiC at the interface of the silicon(Si)and carbon(C)contact to create a stable chemical connection.The obtained SiNWs-CC(SiNWs@CC)composites can be directly used as lithium anodes,exhibiting high initial coulombic efficiency(86.4%)and stable cycling specific capacity(2437.4 mA h g^(-1)at 0.5 A g^(-1)after 165 cycles).In addition,various SiNWs@C composite electrodes are easily prepared using this method.
文摘This study addresses the challenge of real-time resistivity gradient measurement in the Czochralski(CZ)silicon production process.Due to the inability to directly measure this parameter,we propose a Long Short-Term Memory soft-sensing model based on Convolutional Neural Network(CNN)and attention mechanism(CNN-ALSTM)that enhances traditional LSTM by integrating CNN and attention mechanism to overcome time lag variations during silicon pulling.The CNN module extracts spatial features from multi-source sensor data,while the attention-enhanced LSTM(ALSTM)dynamically adjusts historical parameter weights,enabling accurate resistivity gradient prediction.Experiments with real production data show that CNN-ALSTM outperforms SVR,FNN,RNN,XGBoost,and GRU,improving prediction accuracy by 11.76%,16.67%,21.05%,30.23%,and 9.09%,respectively.This soft-sensing approach enhances real-time monitoring and optimization of monocrystalline silicon growth.
基金supported by the Natural Science Foundation of Zhejiang Province(Grant No.LQ24F040007)the National Natural Science Foundation of China(Grant No.U22A2075)the Opening Project of State Key Laboratory of Polymer Materials Engineering(Sichuan University)(Grant No.sklpme2024-1-21).
文摘To address the increasing demand for massive data storage and processing,brain-inspired neuromorphic comput-ing systems based on artificial synaptic devices have been actively developed in recent years.Among the various materials inves-tigated for the fabrication of synaptic devices,silicon carbide(SiC)has emerged as a preferred choices due to its high electron mobility,superior thermal conductivity,and excellent thermal stability,which exhibits promising potential for neuromorphic applications in harsh environments.In this review,the recent progress in SiC-based synaptic devices is summarized.Firstly,an in-depth discussion is conducted regarding the categories,working mechanisms,and structural designs of these devices.Subse-quently,several application scenarios for SiC-based synaptic devices are presented.Finally,a few perspectives and directions for their future development are outlined.
基金supported by the National Natural Science Foundation of China (No. 22008256)。
文摘Silicon is believed to be a critical anode material for approaching the roadmap of lithium-ion batteries due to its high specific capacity. But this aim has been hindered by the quick capacity fading of its electrodes during repeated charge–discharge cycles. In this work, a “soft-hard”double-layer coating has been proposed and carried out on ball-milled silicon particles. It is composed of inside conductive pathway and outside elastic coating, which is achieved by decomposing a conductive graphite layer on the silicon surface and further coating it with a polymer layer.The incorporation of the second elastic coating on the inside carbon coating enables silicon particles strongly interacted with binders, thereby making the electrodes displaying an obviously improved cycling stability. As-obtained double-coated silicon anodes deliver a reversible capacity of 2280 m Ah g^(-1)at the voltage of 0.05–2 V, and maintains over 1763 mAh g^(-1)after 50 cycles. The double-layer coating does not crack after the repeated cycling, critical for the robust performance of the electrodes. In addition, as-obtained silicon particles are mixed with commercial graphite to make actual anodes for lithium-ion batteries. A capacity of 714 mAh g^(-1)has been achieved based on the total mass of the electrodes containing 10 wt.% double-coated silicon particles. Compared with traditional carbon coating or polymeric coating, the double-coating electrodes display a much better performance. Therefore, the double-coating strategy can give inspiration for better design and synthesis of silicon anodes, as well as other battery materials.
基金supported by the Science and Technology Research and Development Plan of the China State Railway Group Company Limited(No.Q2023J012).
文摘Purpose–The brake pipe system was an essential braking component of the railway freight trains,but the existing E-type sealing rings had problems such as insufficient low-temperature resistance,poor heat stability and short service life.To address these issues,low-phenyl silicone rubber was prepared and tested,and the finite element analysis and experimental studies on the sealing performance of its sealing rings were carried out.Design/methodology/approach–The low-temperature resistance and thermal stability of the prepared lowphenyl silicone rubber were studied using low-temperature tensile testing,differential scanning calorimetry,dynamic thermomechanical analysis and thermogravimetric analysis.The sealing performance of the lowphenyl silicone rubber sealing ring was studied by using finite element analysis software abaqus and experiments.Findings–The prepared low-phenyl silicone rubber sealing ring possessed excellent low-temperature resistance and thermal stability.According to the finite element analysis results,the finish of the flange sealing surface and groove outer edge should be ensured,and extrusion damage should be avoided.The sealing rings were more susceptible to damage in high compression ratio and/or low-temperature environments.When the sealing effect was ensured,a small compression ratio should be selected,and rubbers with hardness and elasticity less affected by temperature should be selected.The prepared low-phenyl silicone rubber sealing ring had zero leakage at both room temperature(RT)and�508C.Originality/value–The innovation of this study is that it provides valuable data and experience for the future development of the sealing rings used in the brake pipe flange joints of the railway freight cars in China.
