Extraterrestrial phenomena have influenced Earth’s processes throughout geological history.Evaluating the impact of extraterrestrial material on the environment is crucial for understanding the evolution of Earth and...Extraterrestrial phenomena have influenced Earth’s processes throughout geological history.Evaluating the impact of extraterrestrial material on the environment is crucial for understanding the evolution of Earth and life.This study incorporates the investigation of micrometeorites(MMs),abundant cosmic materials on Earth,to understand their influence on the chemical composition and biogeochemistry of the ocean.Comprehensive etching and flux analyses reveal that∼95%of cosmic spherules(CSs)entering seawater are etched or wholly dissolved,supplying nutrients to phytoplankton.Barred spherules show the highest degree of etching(∼19%),followed by porphyritic(∼17%),glass(∼15%),cryptocrystalline(∼12%),scoriaceous(∼10%),G-type(∼9%),and I-type(∼6%).Annually,∼3080 tonnes(t)of olivine from MMs dissolve into seawater,contributing∼495 t of Mg^(2+),∼1110 t of Fe^(2+),and∼1928 t of silicic acid.This signifies that over the Indian Ocean’s∼40 Myr history,∼23 Gt of olivine from CSs has dissolved,providing nutrients to seawater and sequestering∼7 Gt of CO_(2).The world ocean during this time has sequestered∼35 Gt of CO_(2),with fluctuations influenced by extraterrestrial activity.For instance,the Veritas event,lasting∼1.5 Myr,sequestered∼6 Gt of CO_(2)from the atmosphere.A robust flux calculation based on∼2 t of deep-sea sediments from 3610 MMs provides a more accurate estimate of the time-averaged flux of∼229 t yr^(−1).These comprehensive analyses reveal MM’s original characteristics,post-deposition processes,geological record and their overall impact on Earth’s marine environments,thereby contributing to our knowledge of the interconnection between terrestrial and extraterrestrial processes.展开更多
The highly efficient manufacturing of atomic-scale smooth β-Ga_(2)O_(3)surface is fairly challenging because β-Ga_(2)O_(3)is a typical difficult-to-machine material.In this study,a novel plasma dry etching method na...The highly efficient manufacturing of atomic-scale smooth β-Ga_(2)O_(3)surface is fairly challenging because β-Ga_(2)O_(3)is a typical difficult-to-machine material.In this study,a novel plasma dry etching method named plasma-based atom-selective etching(PASE)is proposed to achieve the highly efficient,atomic-scale,and damage-free polishing of β-Ga_(2)O_(3).The plasma is excited through the inductive coupling principle and carbon tetrafluoride is utilized as the main reaction gas to etch β-Ga_(2)O_(3).The core of PASE polishing of β-Ga_(2)O_(3)is the remarkable lateral etching effect,which is ensured by both the intrinsic property of the surface and the extrinsic temperature condition.As revealed by density functional theory-based calculations,the intrinsic difference in the etching energy barrier of atoms at the step edge(2.36 eV)and in the terrace plane(4.37 eV)determines their difference in the etching rate,and their etching rate difference can be greatly enlarged by increasing the extrinsic temperature.The polishing of β-Ga_(2)O_(3)based on the lateral etching effect is further verified in the etching experiments.The Sa roughness of β-Ga_(2)O_(3)(001)substrate is reduced from 14.8 nm to 0.057 nm within 120 s,and the corresponding material removal rate reaches up to 20.96μm·min^(−1).The polished β-Ga_(2)O_(3)displays significantly improved crystalline quality and photoluminescence intensity,and the polishing effect of PASE is independent of the crystal face of β-Ga_(2)O_(3).In addition,the competition between chemical etching and physical reconstruction,which is determined by temperature and greatly affects the surface state of β-Ga_(2)O_(3),is deeply studied for the first time.These findings not only demonstrate the high-efficiency and high-quality polishing of β-Ga_(2)O_(3)via atmospheric plasma etching but also hold significant implications for guiding future plasma-based surface manufacturing of β-Ga_(2)O_(3).展开更多
Perovskite oxides have been widely applied as an effective catalyst in heterogeneous catalysis.However,the rational design of active catalysts has been restricted by the lack of understanding of the electronic structu...Perovskite oxides have been widely applied as an effective catalyst in heterogeneous catalysis.However,the rational design of active catalysts has been restricted by the lack of understanding of the electronic structure.The correlations between surface properties and bulk electronic structure have been ignored.Herein,a simple handler of LaFeO_(3)with diluted HNO3 was employed to tune the electronic structure and catalytic properties.Experimental analysis and theoretical calculations elucidate that acid etching could raise the Fe valence and enhance Fe-O covalency in the octahedral structure,thereby lessening charge transfer energy.Enhanced Fe-O covalency could lower oxygen vacancy formation energy and enhance oxygen mobility.In-situ DRIFTS results indicated the inherent adsorption capability of Toluene and CO molecules has been greatly improved owing to higher Fe-O covalency.As compared,the catalysts after acid etching exhibited higher catalytic activity,and the T_(90)had a great reduction of 45 and 58℃ for toluene and CO oxidation,respectively.A deeper understanding of electronic structure in perovskite oxides may inspire the design of high-performance catalysts.展开更多
FeCl_(3) solution is commonly used in the etching process of stainless steel.The typical etching waste liquid contains a significant amount of Fe^(3+),Fe^(2+),Cr^(3+),and Ni^(2+),making it difficult to reuse and posin...FeCl_(3) solution is commonly used in the etching process of stainless steel.The typical etching waste liquid contains a significant amount of Fe^(3+),Fe^(2+),Cr^(3+),and Ni^(2+),making it difficult to reuse and posing pollution issues.The FeCl_(3) etching waste liquid was the present subject,which aimed to extract Cr^(3+)and Ni^(2+)by selectively adjusting process parameters.Additionally,it investigates the migration behavior and phase transition mechanisms of the iron,chromium,and nickel in different solution systems during treatment,systematically elucidating the regeneration mechanisms of FeCl_(3) etching waste liquid.The results indicate that Cr and Ni can be recycled by controlling parameters such as pH value,temperature,and the valence states of the ions.Following a selective reduction of Fe^(3+)to Fe^(2+)using Fe powder,98.3%of Cr^(3+)was recovered by adjusting the solution’s pH.Subsequently,93.3%of Ni^(2+)was extracted from the Cr-depleted solution through further adjustments to the process parameters.The recovered Cr and Ni can be used to prepare Fe–Cr and Fe–Ni alloy powders.Furthermore,the FeCl_(3) etching solution was regenerated by oxidizing Fe^(2+)and recovering impurities.The theoretical support for the development of new processes for treating FeCl_(3) etching waste liquid is provided.展开更多
Bimetallic oxides are promising electrocatalysts due to their rich composition,facile synthesis,and favorable stability under oxidizing conditions.This paper innovatively proposes a strategy aimed at constructing a on...Bimetallic oxides are promising electrocatalysts due to their rich composition,facile synthesis,and favorable stability under oxidizing conditions.This paper innovatively proposes a strategy aimed at constructing a one-dimensional heterostructure(Fe–NiO/NiMoO_(4) nanoparticles/nanofibers).The strategy commences with the meticulous treatment of NiMoO_(4) nanofibers,utilizing in situ etching techniques to induce the formation of Prussian Blue Analog compounds.In this process,[Fe(CN)_(6)]^(3-)anions react with the NiMoO_(4) host layer to form a steady NiFe PBA.Subsequently,the surface/interface reconstituted NiMoO_(4) nanofibers undergo direct oxidation,leading to a reconfiguration of the surface structure and the formation of a unique Fe–NiO/NiMoO_(4) one-dimensional heterostructure.The catalyst showed markedly enhanced electrocatalytic performance for the oxygen evolution reaction.Density functional theory results reveal that the incorporation of Fe as a dopant dramatically reduces the Gibbs free energy associated with the rate-determining step in the oxygen evolution reaction pathway.This pivotal transformation directly lowers the activation energy barrier,thereby significantly enhancing electron transfer efficiency.展开更多
With the rapid development of twodimensional MXene materials,numerous preparation strategies have been proposed to enhance synthesis efficiency,mitigate environmental impact,and enable scalability for large-scale prod...With the rapid development of twodimensional MXene materials,numerous preparation strategies have been proposed to enhance synthesis efficiency,mitigate environmental impact,and enable scalability for large-scale production.The compound etching approach,which relies on cationic oxidation of the A element of MAX phase precursors while anions typically adsorb onto MXene surfaces as functional groups,remains the main prevalent strategy.By contrast,synthesis methodologies utilizing elemental etching agents have been rarely reported.Here,we report a new elemental tellurium(Te)-based etching strategy for the preparation of MXene materials with tunable surface chemistry.By selectively removing the A-site element in MAX phases using Te,our approach avoids the use of toxic fluoride reagents and achieves tellurium-terminated surface groups that significantly enhance sodium storage performance.Experimental results show that Te-etched MXene delivers substantially higher capacities(exceeding 50%improvement over conventionally etched MXene)with superior rate capability,retaining high capacity at large current densities and demonstrating over 90%capacity retention after 1000 cycles.This innovative synthetic strategy provides new insight into controllable MXene preparation and performance optimization,while the as-obtained materials hold promises for high-performance sodium-ion batteries and other energy storage systems.展开更多
Lutetium oxide(Lu_(2)O_(3))is recognized as a potential laser crystal material,and it is noted for its high ther⁃mal conductivity,low phonon energy,and strong crystal field.Nevertheless,its high melting point of 2450...Lutetium oxide(Lu_(2)O_(3))is recognized as a potential laser crystal material,and it is noted for its high ther⁃mal conductivity,low phonon energy,and strong crystal field.Nevertheless,its high melting point of 2450℃induces significant temperature gradients,resulting in a proliferation of defects.The scarcity of comprehensive research on this crystal’s defects hinders the enhancement of crystal quality.In this study,we employed the chemical etching method to examine the etching effects on Lu_(2)O_(3)crystals under various conditions and to identify the optimal conditions for investi⁃gating the dislocation defects of Lu_(2)O_(3)crystals(mass fraction 70%H3PO4,160℃,15-18 min).The morphologies of dislocation etch pits on the(111)-and(110)-oriented Lu_(2)O_(3)wafers were characterized using microscopy,scanning electron microscopy and atomic force microscopy.This research addresses the gap in understanding Lu_(2)O_(3)line defects and offers guidance for optimizing the crystal growth process and improving crystal quality.展开更多
Zinc-ion batteries(ZIBs)are considered to be one of the most promising candidates to replace lithium-ion batteries(LIBs)due to the high theoretical capacity,low cost and intrinsic safety.However,zinc dendrites,hydroge...Zinc-ion batteries(ZIBs)are considered to be one of the most promising candidates to replace lithium-ion batteries(LIBs)due to the high theoretical capacity,low cost and intrinsic safety.However,zinc dendrites,hydrogen evolution reaction,surface passivation and other side reactions will inevitably occur during the charging and discharging process of Zn anode,which will seriously affect the cycle stability of the battery and hinder its practical application.The etching strategy of Zn anode has attracted wide attention because of its simple operation and broad commercial prospects,and the etched Zn anode can effectively improve its electrochemical performance.However,there is no comprehensive review of the etching strategy of Zn anode.This review first summarizes the challenges faced by Zn anode,then puts forward the etching mechanisms and properties of acid,salt and other etchants.Finally,based on the above discussion,the challenges and opportunities of Zn anode etching strategy are proposed.展开更多
The continuous evolution of chip manufacturing demands the development of materials with ultra-low dielectric constants.With advantageous dielectric and mechanical properties,initiated chemical vapor deposited(iCVD)po...The continuous evolution of chip manufacturing demands the development of materials with ultra-low dielectric constants.With advantageous dielectric and mechanical properties,initiated chemical vapor deposited(iCVD)poly(1,3,5-trimethyl-1,3,5-trivinyl cyclotrisiloxane)(pV3D3)emerges as a promising candidate.However,previous works have not explored etching for this cyclosiloxane polymer thin film,which is indispensable for potential applications to the back-end-of-line fabrication.Here,we developed an etching process utilizing O2/Ar remote plasma for cyclic removal of iCVD pV3D3 thin film at sub-nanometer scale.We employed in-situ quartz crystal microbalance to investigate the process parameters including the plasma power,plasma duration and O2 flow rate.X-ray photoelectron spectroscopy and cross-sectional microscopy reveal the formation of an oxidized skin layer during the etching process.This skin layer further substantiates an etching mechanism driven by surface oxidation and sputtering.Additionally,this oxidized skin layer leads to improved elastic modulus and hardness and acts as a barrier layer for protecting the bottom cyclosiloxane polymer from further oxidation.展开更多
This study used an anodic etching(AE)method to construct a hierarchical rough surface on the surface of the Cu-bearing antibacterial titanium alloy,Ti-xCu(x=3,5,7 wt%),a three-dimensional structure with nested micro-/...This study used an anodic etching(AE)method to construct a hierarchical rough surface on the surface of the Cu-bearing antibacterial titanium alloy,Ti-xCu(x=3,5,7 wt%),a three-dimensional structure with nested micro-/submicro-pores and internal cavities,which is conducive to the adhesion and growth of bone cells.After AE treatment,with increase of the Cu content in the alloy,the surface of Ti-Cu alloy became sharper,with more fine micropores and internal cavities,thus increasing the surface area.The results indicated that the AE/Ti-Cu alloy exhibited good antibacterial properties and had the effect of inhibiting bacterial biofilm formation.AE treatment could increase the Cu ions release of Ti-Cu alloy in saline,and the higher the Cu content in the alloy,the more Cu ions release,resulting in stronger antibacterial performance of the alloy.AE/Ti-Cu alloy showed excellent biocompatibility,similar to the pure Ti.Therefore,anodic etching is a safe and effective surface treatment method for Ti-Cu alloy,with good clinical application prospects.展开更多
We described a method for obtaining fluorine-free Ti_(3)C_(2)Cl_(2)MXene phases by melting copper in CuCl_(2)instead of aluminum in Ti_(3)AlC_(2).XRD results show that when molten salt CuCl_(2)etches Ti_(3)AlC_(2),it ...We described a method for obtaining fluorine-free Ti_(3)C_(2)Cl_(2)MXene phases by melting copper in CuCl_(2)instead of aluminum in Ti_(3)AlC_(2).XRD results show that when molten salt CuCl_(2)etches Ti_(3)AlC_(2),it forms an intermediate product Ti_(3)CuC_(2),and then reacts with Ti_(3)CuC_(2)to obtain Ti_(3)C_(2)Cl_(2).The reaction of Ti_(3)AlC_(2)and CuCl_(2)at a temperature of 800℃for 2 h to obtain Ti_(3)C_(2)Cl_(2)with an optimal lamellar structure is shown in SEM results.The pseudopotential plane-wave(PP-PW)method is used to calculate on the electronic structure.The etching mechanism is investigated by the total energies of each substance.The chemical reaction of Ti_(3)AlC_(2)and CuCl_(2)will first become Ti_(3)CuC_(2)and Cu,and then become Ti_(3)C_(2)Cl_(2)during the Lewis acid etching process,which are consistent with the experimental results.展开更多
Quartz crystals are the most widely used material in resonant sensors,owing to their excellent piezoelectric and mechanical properties.With the development of portable and wearable devices,higher processing efficiency...Quartz crystals are the most widely used material in resonant sensors,owing to their excellent piezoelectric and mechanical properties.With the development of portable and wearable devices,higher processing efficiency and geometrical precision are required.Wet etching has been proven to be the most efficient etching method for large-scale production of quartz devices,and many wet etching approaches have been developed over the years.However,until now,there has been no systematic review of quartz crystal etching in liquid phase environments.Therefore,this article provides a comprehensive review of the development of wet etching processes and the achievements of the latest research in thisfield,covering conventional wet etching,additive etching,laser-induced backside wet etching,electrochemical etching,and electrochemical discharge machining.For each technique,a brief overview of its characteristics is provided,associated problems are described,and possible solutions are discussed.This review should provide an essential reference and guidance for the future development of processing strategies for the manufacture of quartz crystal devices.展开更多
Molten-alkali etching has been widely used to reveal dislocations in 4H silicon carbide(4H-SiC),which has promoted the identification and statistics of dislocation density in 4H-SiC single crystals.However,the etching...Molten-alkali etching has been widely used to reveal dislocations in 4H silicon carbide(4H-SiC),which has promoted the identification and statistics of dislocation density in 4H-SiC single crystals.However,the etching mechanism of 4H-SiC is limited misunderstood.In this letter,we reveal the anisotropic etching mechanism of the Si face and C face of 4H-SiC by combining molten-KOH etching,X-ray photoelectron spectroscopy(XPS)and first-principles investigations.The activation energies for the molten-KOH etching of the C face and Si face of 4H-SiC are calculated to be 25.09 and 35.75 kcal/mol,respectively.The molten-KOH etching rate of the C face is higher than the Si face.Combining XPS analysis and first-principles calculations,we find that the molten-KOH etching of 4H-SiC is proceeded by the cycling of the oxidation of 4H-SiC by the dissolved oxygen and the removal of oxides by molten KOH.The faster etching rate of the C face is caused by the fact that the oxides on the C face are unstable,and easier to be removed with molten alkali,rather than the C face being easier to be oxidized.展开更多
Recently,SnPS_(3) has gained attention as an impressive sodium-ion battery anode material because of its significant theoretical specific capacity derived from the conversion-alloying reaction mechanism.Nevertheless,i...Recently,SnPS_(3) has gained attention as an impressive sodium-ion battery anode material because of its significant theoretical specific capacity derived from the conversion-alloying reaction mechanism.Nevertheless,its practical applicability is restricted by insufficient rate ability,and severe capacity loss due to inadequate electrical conductivity and dramatic volume expansion.Inspired by the electrochemical enhancement effect of MXene substrates and the innovative Lewis acidic etching for MXene preparation,SnPS_(3)/Ti_(3)C_(2)T_(x) MXene(T=-Cl and-O) is constructed by synchronously phospho-sulfurizing Sn/Ti_(3)C_(2)T_(x) precursor.Benefiting from the boosted Na^(+) diffusion and electron transfer rates,as well as the mitigated stress expansion,the synthesized SnPS_(3/)Ti_(3)C_(2)T_(x) composite demonstrates enhanced rate capability(647 mA h g^(-1) at 10 A g^(-1)) alongside satisfactory long-term cycling stability(capacity retention of 94.6% after 2000 cycles at 5 A g^(-1)).Importantly,the assembled sodium-ion full cell delivers an impressive capacity retention of 97.7% after undergoing 1500 cycles at 2 A g^(-1).Moreover,the sodium storage mechanism of the SnPS_(3/)Ti_(3)C_(2)T_(x) electrode is elucidated through in-situ and ex-situ characterizations.This work proposes a novel approach to ameliorate the energy storage performance of thiophosphites by facile in-situ construction of composites with MXene.展开更多
Biomass-H_(2)O gasification is a complex thermochemical reaction,including three processes of volatile removal:homogeneous/heterogeneous reforming,biochar gasification and etching.The rate-determining step is biochar-...Biomass-H_(2)O gasification is a complex thermochemical reaction,including three processes of volatile removal:homogeneous/heterogeneous reforming,biochar gasification and etching.The rate-determining step is biochar-H_(2)O gasification and etching so the DFT is carried out to see the catalytic role of different metal elements(K/Ni)in the zigzag biochar model.The calculation results show that the gasification of biochar-H_(2)O needs to go through four processes:dissociative adsorption of water,hydrogen transfer(hydrogen desorption,hydrogen atom transfer),carbon dissolution and CO desorption.The energy barrier indicated that the most significant step in reducing the activation energy of K is reflected in the hydrogen transfer step,which is reduced from 374.14 kJ/mol to 152.41 kJ/mol;the catalytic effect of Ni is mainly reflected in the carbon dissolution step,which is reduced from 122.34 kJ/mol to 84.8 kJ/mol.The existence of K causes the edge to have a stronger attraction to H and does not destroy theπbonds of biochar molecules.The destruction ofπbonds is mainly due to the role of H free radicals,while the destruction ofπbonds will lead to easier C-C bond rupture.Ni shows a strong attraction to O in OH,which forms strong Ni-O chemical bonds.Ni can also destroy the aromatic structure directly,making the gasification easier to happen.This study explored the catalytic mechanism of K/Ni on the biochar-H_(2)O gasification at the molecular level and looked forward to the potential synergy of K/Ni,laying a foundation for experimental research and catalyst design.展开更多
Currently, a conventional two-step method has been used to generate black silicon （BS） surfaces on silicon substrates for solar cell manufacturing. However, the performances of the solar cell made with such surface ...Currently, a conventional two-step method has been used to generate black silicon （BS） surfaces on silicon substrates for solar cell manufacturing. However, the performances of the solar cell made with such surface generation method are poor, because of the high surface recombination caused by deep etching in the conventional surface generation method for BS. In this work, a modified wet chemical etching solution with additives was developed. A homogeneous BS layer with random porous structure was obtained from the modified solution in only one step at room temperature. The BS layer had low reflectivity and shallow etching depth. The additive in the etch solution performs the function of pH-modulation. After 16-min etching, the etching depth in the samples was approximately 200 nm, and the spectrum-weighted-reflectivity in the range from 300 nm to 1200 nm was below 5%. BS solar cells were fabricated in the production line. The decreased etching depth can improve the electrical performance of solar cells because of the decrease in surface recombination. An efficiency of 15.63% for the modified etching BS solar cells was achieved on a large area, p- type single crystalline silicon substrate with a 624.32-mV open circuit voltage and a 77.88% fill factor.展开更多
The aluminum foil for high voltage aluminum electrolytic capacitor was immersed in 0.5 mol/L H3PO4 or 0.125 mol/L NaOH solution at 40 ℃ for different time and then DC electro-etched in 1 mol/L HC1＋2.5 mol/L H2SO4 el...The aluminum foil for high voltage aluminum electrolytic capacitor was immersed in 0.5 mol/L H3PO4 or 0.125 mol/L NaOH solution at 40 ℃ for different time and then DC electro-etched in 1 mol/L HC1＋2.5 mol/L H2SO4 electrolyte at 80 ℃. The pitting potential and self corrosion potential of A1 foil were measured with polarization curves （PC）. The potentiostatic current--time curve was recorded and the surface and cross section images of etched A1 foil were observed with SEM. The electrochemical impedance spectroscopy （EIS） of etched A1 foil and potential transient curves （PTC） during initial etching stage were measured. The results show the chemical pretreatments can activate A1 foil surface, facilitate the absorption, diffusion and migration of C1- onto the A1 foil during etching, and improve the initiation rate of meta-stable pits and density of stable pits and tunnels, leading to much increase in the real surface area and special capacitance of etched A1 foil.展开更多
The Al foil for high voltage Al electrolytic capacitor usage was immersed in 5.0%NaOH solution containing trace amount of Zn2＋and Zn was chemically plated on its surface through an immersion-reduction reaction. Such ...The Al foil for high voltage Al electrolytic capacitor usage was immersed in 5.0%NaOH solution containing trace amount of Zn2＋and Zn was chemically plated on its surface through an immersion-reduction reaction. Such Zn-deposited Al foil was quickly transferred into HCl-H 2 SO 4 solution for DC-etching. The effects of Zn impurity on the surface and cross-section etching morphologies and electrochemical behavior of Al foil were investigated by SEM, polarization curve （PC） and electrochemical impedance spectroscopy （EIS）. The special capacitance of 100 V formation voltage of etched foil was measured. The results show that the chemical plating Zn on Al substrate in alkali solution can reduce the pitting corrosion resistance, enhance the pitting current density and improve the density and uniform distribution of pits and tunnels due to formation of the micro Zn-Al galvanic local cells. The special capacitance of etched foil grows with the increase of Zn2＋concentration.展开更多
In order to obtain bioelectrical impedance electrodes with high stability, the chemical etching process was used to fabricate the copper electrode with a series of surface microstructures. By changing the etching proc...In order to obtain bioelectrical impedance electrodes with high stability, the chemical etching process was used to fabricate the copper electrode with a series of surface microstructures. By changing the etching processing parameters, some comparison experiments were performed to reveal the influence of etching time, etching temperature, etching liquid concentration, and sample sizes on the etching rate and surface microstructures of copper electrode. The result shows that the etching rate is decreased with increasing etching time, and is increased with increasing etching temperature. Moreover, it is found that the sample size has little influence on the etching rate. After choosing the reasonable etching liquid composition （formulation 3）, the copper electrode with many surface microstructures can be obtained by chemical etching process at room temperature for 20 rain. In addition, using the alternating current impedance test of electrode-electrode for 24 h, the copper electrode with a series of surface microstructures fabricated by the etching process presents a more stable impedance value compared with the electrocardiograph （ECG） electrode, resulting from the reliable surface contact of copper electrode-electrode.展开更多
Optical waveguides in silica-on-silicon are one of the key elements in optical communications.The processes of deep etching silica waveguides using resist and metal masks in RIE plasma are investigated.The etching res...Optical waveguides in silica-on-silicon are one of the key elements in optical communications.The processes of deep etching silica waveguides using resist and metal masks in RIE plasma are investigated.The etching responses,including etching rate and selectivity as functions of variation of parameters,are modeled with a 3D neural network.A novel resist/metal combined mask that can overcome the single-layer masks’ limitations is developed for enhancing the waveguides deep etching and low-loss optical waveguides are fabricated at last.展开更多
基金ISRO-RESPOND GAP3332 and PMN-MOES GAP2175 Project support this work.NIO-PMN and MOES-NCPOR supported the deep-sea and Antarctica micrometeorite collections,respectively.
文摘Extraterrestrial phenomena have influenced Earth’s processes throughout geological history.Evaluating the impact of extraterrestrial material on the environment is crucial for understanding the evolution of Earth and life.This study incorporates the investigation of micrometeorites(MMs),abundant cosmic materials on Earth,to understand their influence on the chemical composition and biogeochemistry of the ocean.Comprehensive etching and flux analyses reveal that∼95%of cosmic spherules(CSs)entering seawater are etched or wholly dissolved,supplying nutrients to phytoplankton.Barred spherules show the highest degree of etching(∼19%),followed by porphyritic(∼17%),glass(∼15%),cryptocrystalline(∼12%),scoriaceous(∼10%),G-type(∼9%),and I-type(∼6%).Annually,∼3080 tonnes(t)of olivine from MMs dissolve into seawater,contributing∼495 t of Mg^(2+),∼1110 t of Fe^(2+),and∼1928 t of silicic acid.This signifies that over the Indian Ocean’s∼40 Myr history,∼23 Gt of olivine from CSs has dissolved,providing nutrients to seawater and sequestering∼7 Gt of CO_(2).The world ocean during this time has sequestered∼35 Gt of CO_(2),with fluctuations influenced by extraterrestrial activity.For instance,the Veritas event,lasting∼1.5 Myr,sequestered∼6 Gt of CO_(2)from the atmosphere.A robust flux calculation based on∼2 t of deep-sea sediments from 3610 MMs provides a more accurate estimate of the time-averaged flux of∼229 t yr^(−1).These comprehensive analyses reveal MM’s original characteristics,post-deposition processes,geological record and their overall impact on Earth’s marine environments,thereby contributing to our knowledge of the interconnection between terrestrial and extraterrestrial processes.
基金supported by the National Natural Science Foundation of China(52375437,52035009)the Natural Science Foundation of Guangdong Province(2024B1515020027)+2 种基金the Shenzhen Science and Technology Program(Grant No.KQTD20170810110250357)for the financial supportthe assistance of SUSTech Core Research Facilitiessupported by Shenzhen Engineering Research Center for Semiconductorspecific Equipment。
文摘The highly efficient manufacturing of atomic-scale smooth β-Ga_(2)O_(3)surface is fairly challenging because β-Ga_(2)O_(3)is a typical difficult-to-machine material.In this study,a novel plasma dry etching method named plasma-based atom-selective etching(PASE)is proposed to achieve the highly efficient,atomic-scale,and damage-free polishing of β-Ga_(2)O_(3).The plasma is excited through the inductive coupling principle and carbon tetrafluoride is utilized as the main reaction gas to etch β-Ga_(2)O_(3).The core of PASE polishing of β-Ga_(2)O_(3)is the remarkable lateral etching effect,which is ensured by both the intrinsic property of the surface and the extrinsic temperature condition.As revealed by density functional theory-based calculations,the intrinsic difference in the etching energy barrier of atoms at the step edge(2.36 eV)and in the terrace plane(4.37 eV)determines their difference in the etching rate,and their etching rate difference can be greatly enlarged by increasing the extrinsic temperature.The polishing of β-Ga_(2)O_(3)based on the lateral etching effect is further verified in the etching experiments.The Sa roughness of β-Ga_(2)O_(3)(001)substrate is reduced from 14.8 nm to 0.057 nm within 120 s,and the corresponding material removal rate reaches up to 20.96μm·min^(−1).The polished β-Ga_(2)O_(3)displays significantly improved crystalline quality and photoluminescence intensity,and the polishing effect of PASE is independent of the crystal face of β-Ga_(2)O_(3).In addition,the competition between chemical etching and physical reconstruction,which is determined by temperature and greatly affects the surface state of β-Ga_(2)O_(3),is deeply studied for the first time.These findings not only demonstrate the high-efficiency and high-quality polishing of β-Ga_(2)O_(3)via atmospheric plasma etching but also hold significant implications for guiding future plasma-based surface manufacturing of β-Ga_(2)O_(3).
基金the National Natural Science Foundation of China(Nos.22376178,22322606,22276105)the National Key Research and Development Program of China(No.2022YFC3704300)the Beijing Natural Science Foundation(No.8222054).
文摘Perovskite oxides have been widely applied as an effective catalyst in heterogeneous catalysis.However,the rational design of active catalysts has been restricted by the lack of understanding of the electronic structure.The correlations between surface properties and bulk electronic structure have been ignored.Herein,a simple handler of LaFeO_(3)with diluted HNO3 was employed to tune the electronic structure and catalytic properties.Experimental analysis and theoretical calculations elucidate that acid etching could raise the Fe valence and enhance Fe-O covalency in the octahedral structure,thereby lessening charge transfer energy.Enhanced Fe-O covalency could lower oxygen vacancy formation energy and enhance oxygen mobility.In-situ DRIFTS results indicated the inherent adsorption capability of Toluene and CO molecules has been greatly improved owing to higher Fe-O covalency.As compared,the catalysts after acid etching exhibited higher catalytic activity,and the T_(90)had a great reduction of 45 and 58℃ for toluene and CO oxidation,respectively.A deeper understanding of electronic structure in perovskite oxides may inspire the design of high-performance catalysts.
基金financially supported by the National Natural Science Foundation of China(Nos.52074078 and 52374327)the Applied Fundamental Research Program of Liaoning Province(No.2023JH2/101600002)+5 种基金the Liaoning Provincial Natural Science Foundation of China(No.2022-YQ-09)the Shenyang Young Middle-Aged Scientific and Technological Innovation Talent Support Program,China(No.RC220491)the Liaoning Province Steel Industry-University-Research Innovation Alliance Cooperation Project of Bensteel Group,China(No.KJBLM202202)the Fundamental Research Funds for the Central Universities,China(Nos.N2201023 and N2325009)the Key Scientific Research Project of Liaoning Provincial Department of Education(2024JYTZD-03)the 111 Project(B16009).
文摘FeCl_(3) solution is commonly used in the etching process of stainless steel.The typical etching waste liquid contains a significant amount of Fe^(3+),Fe^(2+),Cr^(3+),and Ni^(2+),making it difficult to reuse and posing pollution issues.The FeCl_(3) etching waste liquid was the present subject,which aimed to extract Cr^(3+)and Ni^(2+)by selectively adjusting process parameters.Additionally,it investigates the migration behavior and phase transition mechanisms of the iron,chromium,and nickel in different solution systems during treatment,systematically elucidating the regeneration mechanisms of FeCl_(3) etching waste liquid.The results indicate that Cr and Ni can be recycled by controlling parameters such as pH value,temperature,and the valence states of the ions.Following a selective reduction of Fe^(3+)to Fe^(2+)using Fe powder,98.3%of Cr^(3+)was recovered by adjusting the solution’s pH.Subsequently,93.3%of Ni^(2+)was extracted from the Cr-depleted solution through further adjustments to the process parameters.The recovered Cr and Ni can be used to prepare Fe–Cr and Fe–Ni alloy powders.Furthermore,the FeCl_(3) etching solution was regenerated by oxidizing Fe^(2+)and recovering impurities.The theoretical support for the development of new processes for treating FeCl_(3) etching waste liquid is provided.
基金supported by the National Natural Science Foundation of China(52203257)Natural Science Foundation of Heilongjiang Province(YQ2022B008).
文摘Bimetallic oxides are promising electrocatalysts due to their rich composition,facile synthesis,and favorable stability under oxidizing conditions.This paper innovatively proposes a strategy aimed at constructing a one-dimensional heterostructure(Fe–NiO/NiMoO_(4) nanoparticles/nanofibers).The strategy commences with the meticulous treatment of NiMoO_(4) nanofibers,utilizing in situ etching techniques to induce the formation of Prussian Blue Analog compounds.In this process,[Fe(CN)_(6)]^(3-)anions react with the NiMoO_(4) host layer to form a steady NiFe PBA.Subsequently,the surface/interface reconstituted NiMoO_(4) nanofibers undergo direct oxidation,leading to a reconfiguration of the surface structure and the formation of a unique Fe–NiO/NiMoO_(4) one-dimensional heterostructure.The catalyst showed markedly enhanced electrocatalytic performance for the oxygen evolution reaction.Density functional theory results reveal that the incorporation of Fe as a dopant dramatically reduces the Gibbs free energy associated with the rate-determining step in the oxygen evolution reaction pathway.This pivotal transformation directly lowers the activation energy barrier,thereby significantly enhancing electron transfer efficiency.
基金supported by the National Natural Science Foundation of China(52472228,22309202)Natural Science Foundation of Sichuan Province(2023NSFSC1942)the Gusu Leading Talents Program(ZXL2023190)。
文摘With the rapid development of twodimensional MXene materials,numerous preparation strategies have been proposed to enhance synthesis efficiency,mitigate environmental impact,and enable scalability for large-scale production.The compound etching approach,which relies on cationic oxidation of the A element of MAX phase precursors while anions typically adsorb onto MXene surfaces as functional groups,remains the main prevalent strategy.By contrast,synthesis methodologies utilizing elemental etching agents have been rarely reported.Here,we report a new elemental tellurium(Te)-based etching strategy for the preparation of MXene materials with tunable surface chemistry.By selectively removing the A-site element in MAX phases using Te,our approach avoids the use of toxic fluoride reagents and achieves tellurium-terminated surface groups that significantly enhance sodium storage performance.Experimental results show that Te-etched MXene delivers substantially higher capacities(exceeding 50%improvement over conventionally etched MXene)with superior rate capability,retaining high capacity at large current densities and demonstrating over 90%capacity retention after 1000 cycles.This innovative synthetic strategy provides new insight into controllable MXene preparation and performance optimization,while the as-obtained materials hold promises for high-performance sodium-ion batteries and other energy storage systems.
基金Supported by National Key Research and Development Program of China(2021YFB3601403)National Natural Science Foundation of China(62105181)Taishan Scholar of Shandong Province(tsqn202306014)。
文摘Lutetium oxide(Lu_(2)O_(3))is recognized as a potential laser crystal material,and it is noted for its high ther⁃mal conductivity,low phonon energy,and strong crystal field.Nevertheless,its high melting point of 2450℃induces significant temperature gradients,resulting in a proliferation of defects.The scarcity of comprehensive research on this crystal’s defects hinders the enhancement of crystal quality.In this study,we employed the chemical etching method to examine the etching effects on Lu_(2)O_(3)crystals under various conditions and to identify the optimal conditions for investi⁃gating the dislocation defects of Lu_(2)O_(3)crystals(mass fraction 70%H3PO4,160℃,15-18 min).The morphologies of dislocation etch pits on the(111)-and(110)-oriented Lu_(2)O_(3)wafers were characterized using microscopy,scanning electron microscopy and atomic force microscopy.This research addresses the gap in understanding Lu_(2)O_(3)line defects and offers guidance for optimizing the crystal growth process and improving crystal quality.
基金supported by the Science and Technology Research Project of the Education Department of Jilin Province (JJKH20230803KJ)。
文摘Zinc-ion batteries(ZIBs)are considered to be one of the most promising candidates to replace lithium-ion batteries(LIBs)due to the high theoretical capacity,low cost and intrinsic safety.However,zinc dendrites,hydrogen evolution reaction,surface passivation and other side reactions will inevitably occur during the charging and discharging process of Zn anode,which will seriously affect the cycle stability of the battery and hinder its practical application.The etching strategy of Zn anode has attracted wide attention because of its simple operation and broad commercial prospects,and the etched Zn anode can effectively improve its electrochemical performance.However,there is no comprehensive review of the etching strategy of Zn anode.This review first summarizes the challenges faced by Zn anode,then puts forward the etching mechanisms and properties of acid,salt and other etchants.Finally,based on the above discussion,the challenges and opportunities of Zn anode etching strategy are proposed.
基金the funding from the National Natural Science Foundation of China(22178301 and 21938011)the grant from the Science&Technology Department of Zhejiang Province(2023C01182)+3 种基金the funding from the Natural Science Foundation of Zhejiang Province(LR21B060003)supported by the Fundamental Research Funds for the Central Universities(226-2024-00023)Shanxi Institute of Zhejiang University for New Materials and Chemical Industry(2022SZ-TD005)Quzhou Science and Technology Program(2021NC02).
文摘The continuous evolution of chip manufacturing demands the development of materials with ultra-low dielectric constants.With advantageous dielectric and mechanical properties,initiated chemical vapor deposited(iCVD)poly(1,3,5-trimethyl-1,3,5-trivinyl cyclotrisiloxane)(pV3D3)emerges as a promising candidate.However,previous works have not explored etching for this cyclosiloxane polymer thin film,which is indispensable for potential applications to the back-end-of-line fabrication.Here,we developed an etching process utilizing O2/Ar remote plasma for cyclic removal of iCVD pV3D3 thin film at sub-nanometer scale.We employed in-situ quartz crystal microbalance to investigate the process parameters including the plasma power,plasma duration and O2 flow rate.X-ray photoelectron spectroscopy and cross-sectional microscopy reveal the formation of an oxidized skin layer during the etching process.This skin layer further substantiates an etching mechanism driven by surface oxidation and sputtering.Additionally,this oxidized skin layer leads to improved elastic modulus and hardness and acts as a barrier layer for protecting the bottom cyclosiloxane polymer from further oxidation.
基金financially supported by the Natural Science Foundation of Liaoning Province(No.2022-MS-079).
文摘This study used an anodic etching(AE)method to construct a hierarchical rough surface on the surface of the Cu-bearing antibacterial titanium alloy,Ti-xCu(x=3,5,7 wt%),a three-dimensional structure with nested micro-/submicro-pores and internal cavities,which is conducive to the adhesion and growth of bone cells.After AE treatment,with increase of the Cu content in the alloy,the surface of Ti-Cu alloy became sharper,with more fine micropores and internal cavities,thus increasing the surface area.The results indicated that the AE/Ti-Cu alloy exhibited good antibacterial properties and had the effect of inhibiting bacterial biofilm formation.AE treatment could increase the Cu ions release of Ti-Cu alloy in saline,and the higher the Cu content in the alloy,the more Cu ions release,resulting in stronger antibacterial performance of the alloy.AE/Ti-Cu alloy showed excellent biocompatibility,similar to the pure Ti.Therefore,anodic etching is a safe and effective surface treatment method for Ti-Cu alloy,with good clinical application prospects.
基金Funded by the National Natural Science Foundation for Young Scholars of China(No.51302073)the Hubei Provincial Key Laboratory of Green Materials for Light IndustryHubei University of Technology(No.202307B07)。
文摘We described a method for obtaining fluorine-free Ti_(3)C_(2)Cl_(2)MXene phases by melting copper in CuCl_(2)instead of aluminum in Ti_(3)AlC_(2).XRD results show that when molten salt CuCl_(2)etches Ti_(3)AlC_(2),it forms an intermediate product Ti_(3)CuC_(2),and then reacts with Ti_(3)CuC_(2)to obtain Ti_(3)C_(2)Cl_(2).The reaction of Ti_(3)AlC_(2)and CuCl_(2)at a temperature of 800℃for 2 h to obtain Ti_(3)C_(2)Cl_(2)with an optimal lamellar structure is shown in SEM results.The pseudopotential plane-wave(PP-PW)method is used to calculate on the electronic structure.The etching mechanism is investigated by the total energies of each substance.The chemical reaction of Ti_(3)AlC_(2)and CuCl_(2)will first become Ti_(3)CuC_(2)and Cu,and then become Ti_(3)C_(2)Cl_(2)during the Lewis acid etching process,which are consistent with the experimental results.
基金supported by the Natural Science Foundation of China (Grant No.12234005)the major research and development program of Jiangsu Province (Grant Nos.BE2021007-2 and BK20222007)。
文摘Quartz crystals are the most widely used material in resonant sensors,owing to their excellent piezoelectric and mechanical properties.With the development of portable and wearable devices,higher processing efficiency and geometrical precision are required.Wet etching has been proven to be the most efficient etching method for large-scale production of quartz devices,and many wet etching approaches have been developed over the years.However,until now,there has been no systematic review of quartz crystal etching in liquid phase environments.Therefore,this article provides a comprehensive review of the development of wet etching processes and the achievements of the latest research in thisfield,covering conventional wet etching,additive etching,laser-induced backside wet etching,electrochemical etching,and electrochemical discharge machining.For each technique,a brief overview of its characteristics is provided,associated problems are described,and possible solutions are discussed.This review should provide an essential reference and guidance for the future development of processing strategies for the manufacture of quartz crystal devices.
基金This work is supported by the Natural Science Foundation of China(Grant Nos.62274143&62204216)Joint Funds of the Zhejiang Provincial Natural Science Foundation of China(Grant Nos.LHZSD24E020001)+4 种基金the“Pioneer”and“Leading Goose”R&D Program of Zhejiang(Grant Nos.2022C0102&2023C01010)Partial support was provided by the Leading Innovative and Entrepreneur Team Introduction Program of Hangzhou(Grant No.TD2022012)Fundamental Research Funds for the Central Universities(Grant No.226-2022-00200)the Natural Science Foundation of China for Innovative Research Groups(Grant No.61721005)the Open Fund of Zhejiang Provincial Key Laboratory of Wide Bandgap Semiconductors,Hangzhou Global Scientific and Technological Innovation Center,Zhejiang University.
文摘Molten-alkali etching has been widely used to reveal dislocations in 4H silicon carbide(4H-SiC),which has promoted the identification and statistics of dislocation density in 4H-SiC single crystals.However,the etching mechanism of 4H-SiC is limited misunderstood.In this letter,we reveal the anisotropic etching mechanism of the Si face and C face of 4H-SiC by combining molten-KOH etching,X-ray photoelectron spectroscopy(XPS)and first-principles investigations.The activation energies for the molten-KOH etching of the C face and Si face of 4H-SiC are calculated to be 25.09 and 35.75 kcal/mol,respectively.The molten-KOH etching rate of the C face is higher than the Si face.Combining XPS analysis and first-principles calculations,we find that the molten-KOH etching of 4H-SiC is proceeded by the cycling of the oxidation of 4H-SiC by the dissolved oxygen and the removal of oxides by molten KOH.The faster etching rate of the C face is caused by the fact that the oxides on the C face are unstable,and easier to be removed with molten alkali,rather than the C face being easier to be oxidized.
基金financially National Natural Science Foundation of China (Grant Number: 22265018)Key Project of Natural Science Foundation of Jiangxi Province (Grant Number: 20232ACB204010)。
文摘Recently,SnPS_(3) has gained attention as an impressive sodium-ion battery anode material because of its significant theoretical specific capacity derived from the conversion-alloying reaction mechanism.Nevertheless,its practical applicability is restricted by insufficient rate ability,and severe capacity loss due to inadequate electrical conductivity and dramatic volume expansion.Inspired by the electrochemical enhancement effect of MXene substrates and the innovative Lewis acidic etching for MXene preparation,SnPS_(3)/Ti_(3)C_(2)T_(x) MXene(T=-Cl and-O) is constructed by synchronously phospho-sulfurizing Sn/Ti_(3)C_(2)T_(x) precursor.Benefiting from the boosted Na^(+) diffusion and electron transfer rates,as well as the mitigated stress expansion,the synthesized SnPS_(3/)Ti_(3)C_(2)T_(x) composite demonstrates enhanced rate capability(647 mA h g^(-1) at 10 A g^(-1)) alongside satisfactory long-term cycling stability(capacity retention of 94.6% after 2000 cycles at 5 A g^(-1)).Importantly,the assembled sodium-ion full cell delivers an impressive capacity retention of 97.7% after undergoing 1500 cycles at 2 A g^(-1).Moreover,the sodium storage mechanism of the SnPS_(3/)Ti_(3)C_(2)T_(x) electrode is elucidated through in-situ and ex-situ characterizations.This work proposes a novel approach to ameliorate the energy storage performance of thiophosphites by facile in-situ construction of composites with MXene.
基金Sponsored by the National Natural Science Foundation of China(Grant No.52276180)the Natural Science Foundation of Heilongjiang Province(Grant No.YQ2022E026).
文摘Biomass-H_(2)O gasification is a complex thermochemical reaction,including three processes of volatile removal:homogeneous/heterogeneous reforming,biochar gasification and etching.The rate-determining step is biochar-H_(2)O gasification and etching so the DFT is carried out to see the catalytic role of different metal elements(K/Ni)in the zigzag biochar model.The calculation results show that the gasification of biochar-H_(2)O needs to go through four processes:dissociative adsorption of water,hydrogen transfer(hydrogen desorption,hydrogen atom transfer),carbon dissolution and CO desorption.The energy barrier indicated that the most significant step in reducing the activation energy of K is reflected in the hydrogen transfer step,which is reduced from 374.14 kJ/mol to 152.41 kJ/mol;the catalytic effect of Ni is mainly reflected in the carbon dissolution step,which is reduced from 122.34 kJ/mol to 84.8 kJ/mol.The existence of K causes the edge to have a stronger attraction to H and does not destroy theπbonds of biochar molecules.The destruction ofπbonds is mainly due to the role of H free radicals,while the destruction ofπbonds will lead to easier C-C bond rupture.Ni shows a strong attraction to O in OH,which forms strong Ni-O chemical bonds.Ni can also destroy the aromatic structure directly,making the gasification easier to happen.This study explored the catalytic mechanism of K/Ni on the biochar-H_(2)O gasification at the molecular level and looked forward to the potential synergy of K/Ni,laying a foundation for experimental research and catalyst design.
文摘Currently, a conventional two-step method has been used to generate black silicon （BS） surfaces on silicon substrates for solar cell manufacturing. However, the performances of the solar cell made with such surface generation method are poor, because of the high surface recombination caused by deep etching in the conventional surface generation method for BS. In this work, a modified wet chemical etching solution with additives was developed. A homogeneous BS layer with random porous structure was obtained from the modified solution in only one step at room temperature. The BS layer had low reflectivity and shallow etching depth. The additive in the etch solution performs the function of pH-modulation. After 16-min etching, the etching depth in the samples was approximately 200 nm, and the spectrum-weighted-reflectivity in the range from 300 nm to 1200 nm was below 5%. BS solar cells were fabricated in the production line. The decreased etching depth can improve the electrical performance of solar cells because of the decrease in surface recombination. An efficiency of 15.63% for the modified etching BS solar cells was achieved on a large area, p- type single crystalline silicon substrate with a 624.32-mV open circuit voltage and a 77.88% fill factor.
基金Project supported by University New Materials Disciplines Constructions Program of Beijing Region,ChinaProject(51172102/E020801) supported by the National Natural Science Foundation of China
文摘The aluminum foil for high voltage aluminum electrolytic capacitor was immersed in 0.5 mol/L H3PO4 or 0.125 mol/L NaOH solution at 40 ℃ for different time and then DC electro-etched in 1 mol/L HC1＋2.5 mol/L H2SO4 electrolyte at 80 ℃. The pitting potential and self corrosion potential of A1 foil were measured with polarization curves （PC）. The potentiostatic current--time curve was recorded and the surface and cross section images of etched A1 foil were observed with SEM. The electrochemical impedance spectroscopy （EIS） of etched A1 foil and potential transient curves （PTC） during initial etching stage were measured. The results show the chemical pretreatments can activate A1 foil surface, facilitate the absorption, diffusion and migration of C1- onto the A1 foil during etching, and improve the initiation rate of meta-stable pits and density of stable pits and tunnels, leading to much increase in the real surface area and special capacitance of etched A1 foil.
基金Project (51172102) supported by the National Natural Science Foundation of ChinaProject (BS2011CL011) supported by Promotive Research Fund for Young and Middle-aged Scientists of Shandong Province(doctor fund),China
文摘The Al foil for high voltage Al electrolytic capacitor usage was immersed in 5.0%NaOH solution containing trace amount of Zn2＋and Zn was chemically plated on its surface through an immersion-reduction reaction. Such Zn-deposited Al foil was quickly transferred into HCl-H 2 SO 4 solution for DC-etching. The effects of Zn impurity on the surface and cross-section etching morphologies and electrochemical behavior of Al foil were investigated by SEM, polarization curve （PC） and electrochemical impedance spectroscopy （EIS）. The special capacitance of 100 V formation voltage of etched foil was measured. The results show that the chemical plating Zn on Al substrate in alkali solution can reduce the pitting corrosion resistance, enhance the pitting current density and improve the density and uniform distribution of pits and tunnels due to formation of the micro Zn-Al galvanic local cells. The special capacitance of etched foil grows with the increase of Zn2＋concentration.
基金Project (2011A090200123) supported by Industry-Universities-Research Cooperation Project of Guangdong Province and Ministry of Education of ChinaProject (111gpy06) supported by Fundamental Research Funds for the Central Universities,ChinaProject (101055807) supported by the Innovative Experiment Plan Project for College Students of Sun Yat-sen University,China
文摘In order to obtain bioelectrical impedance electrodes with high stability, the chemical etching process was used to fabricate the copper electrode with a series of surface microstructures. By changing the etching processing parameters, some comparison experiments were performed to reveal the influence of etching time, etching temperature, etching liquid concentration, and sample sizes on the etching rate and surface microstructures of copper electrode. The result shows that the etching rate is decreased with increasing etching time, and is increased with increasing etching temperature. Moreover, it is found that the sample size has little influence on the etching rate. After choosing the reasonable etching liquid composition （formulation 3）, the copper electrode with many surface microstructures can be obtained by chemical etching process at room temperature for 20 rain. In addition, using the alternating current impedance test of electrode-electrode for 24 h, the copper electrode with a series of surface microstructures fabricated by the etching process presents a more stable impedance value compared with the electrocardiograph （ECG） electrode, resulting from the reliable surface contact of copper electrode-electrode.
文摘Optical waveguides in silica-on-silicon are one of the key elements in optical communications.The processes of deep etching silica waveguides using resist and metal masks in RIE plasma are investigated.The etching responses,including etching rate and selectivity as functions of variation of parameters,are modeled with a 3D neural network.A novel resist/metal combined mask that can overcome the single-layer masks’ limitations is developed for enhancing the waveguides deep etching and low-loss optical waveguides are fabricated at last.
