Solid-state electrolytes(SSEs),as the core component within the next generation of key energy storage technologies-solid-state lithium batteries(SSLBs)-are significantly leading the development of future energy storag...Solid-state electrolytes(SSEs),as the core component within the next generation of key energy storage technologies-solid-state lithium batteries(SSLBs)-are significantly leading the development of future energy storage systems.Among the numerous types of SSEs,inorganic oxide garnet-structured superionic conductors Li7La3Zr2O12(LLZO)crystallized with the cubic Iaˉ3d space group have received considerable attention owing to their highly advantageous intrinsic properties encompassing reasonable lithium-ion conductivity,wide electrochemical voltage window,high shear modulus,and excellent chemical stability with electrodes.However,no SSEs possess all the properties necessary for SSLBs,thus both the ionic conductivity at room temperature and stability in ambient air regarding cubic garnet-based electrolytes are still subject to further improvement.Hence,this review comprehensively covers the nine key structural factors affecting the ion conductivity of garnet-based electrolytes comprising Li concentration,Li vacancy concentration,Li carrier concentration and mobility,Li occupancy at available sites,lattice constant,triangle bottleneck size,oxygen vacancy defects,and Li-O bonding interactions.Furthermore,the general illustration of structures and fundamental features being crucial to chemical stability is examined,including Li concentration,Li-site occupation behavior,and Li-O bonding interactions.Insights into the composition-structure-property relations among cubic garnet-based oxide ionic conductors from the perspective of their crystal structures,revealing the potential compatibility conflicts between ionic transportation and chemical stability resulting from Li-O bonding interactions.We believe that this review will lay the foundation for future reasonable structural design of oxide-based or even other types of superionic conductors,thus assisting in promoting the rapid development of alternative green and sustainable technologies.展开更多
Solid-state electrolytes with high oxidation stability are crucial for achieving high power density allsolid-state lithium batteries.Halide electrolytes are promising candidates due to their outstanding compatibility ...Solid-state electrolytes with high oxidation stability are crucial for achieving high power density allsolid-state lithium batteries.Halide electrolytes are promising candidates due to their outstanding compatibility with cathode materials and high Li^(+)conductivity.However,the electrochemical stability of chloride electrolytes is still limited,leaving them unsuitable for ultrahigh voltage operation.Besides,chemical compatibility issue between sulfide and halide electrolytes affects the electrochemical performance of all-solid-state batteries.Herein,Li-ion conductor Li_(3+x)InCl_(6-x)O_(x) is designed to address these challenges.Li_(3.25)InCl_(5.75)O_(0.25)shows a Li-ion conductivity of 0.90 mS cm^(-1)at room temperature,a high onset oxidation voltage of 3.84 V,fewer by-products at ultrahigh operation voltage,and good chemical compatibility with Li_(5.5)PS_(4.5)Cl_(1.5).The Li_(3.25)InCl_(5.75)O_(0.25)@LiNi_(0.7)Co_(0.1)Mn_(0.2)O_(2)-Li_(3.25)InCl_(5.75)O_(0.25)-VGCF/Li_(3.25)InCl_(5.75)O_(0.25)/Li_(5.5)PS_(4.5)Cl_(1.5)/Li-In battery delivers good electrochemical performances at high operating voltage.This work provides a simple,economical,and effective strategy for designing high-voltage all-solid-state electrolytes.展开更多
The phase composition, microstructure, thermal expansion coefficients, oxygen permeation properties and chemical stability of SrCo0.8Fe0.2O3-δ （SCFM） were investigated and compared with those of SrCo0.8Fe0.2O3-δ（...The phase composition, microstructure, thermal expansion coefficients, oxygen permeation properties and chemical stability of SrCo0.8Fe0.2O3-δ （SCFM） were investigated and compared with those of SrCo0.8Fe0.2O3-δ（SCF）. Single phase SCFM was successfully prepared by a combined EDTA-citric method. SCFM shows a lower thermal expansion coefficient （24× 10^-6-29× 10^-6/K） than SCF between 500 and 1050 ℃, indicating a more stable structure. SCFM shows a high oxygen permeation flux, although the oxygen flux of SCFM decreases slightly because of Mo dopant. Furthermore, it was demonstrated that the doping of Mo in SCF can prevent the order-disorder transition and improves the chemical stability to CO2.展开更多
In this study, Nd-bearing zirconolite-rich ceramics were prepared by solid-state reaction process using CaF2,ZrO2, Ti,TiO2, Fe2 O3 and Nd2O3 as the raw materials. Neodymium was used as trivalent actinide surrogate and...In this study, Nd-bearing zirconolite-rich ceramics were prepared by solid-state reaction process using CaF2,ZrO2, Ti,TiO2, Fe2 O3 and Nd2O3 as the raw materials. Neodymium was used as trivalent actinide surrogate and designed to substitute the Ca and Zr sites of zirconolite with general stoichiometry of Ca1-xZr1-xNd2 xTi2O7（0≤x≤0.3）. Density of Fe-Nd-O sample reaches a maximum value of 4.13 g/cm^2 after being sintered at 1325 ℃ for 42 h. Three major phases, namely zirconolite, perovskite and pseudobrookite, are observed in all these samples. The EDX result shows that Nd2O3 can be successfully incorporated into the lattice structure of the prepared zirconolite-rich minerals and replace the Ca sites of zirconolite and perovskite with Fe3＋ as the charge-compensating ion. Furthermore, the thermal conductivities are all in the range of 1.51-1.67 W/（m·K）. The normalized elemental leaching rates of Ca and Nd in the Fe-Nd-0.2 sample keep in low values of 6.20 × 10^-2 and 4.86 × 10^-4 g/（m^2·d） after 42 d.展开更多
BaCe0.45Zr0.45M0.1O3-δ （M=Y, In） and BaCe0.9Y0.1O3-δ were prepared through the conventional solid state reaction route. The chemical stability was investigated in hydrogen, carbon dioxide, and boiling water. Cryst...BaCe0.45Zr0.45M0.1O3-δ （M=Y, In） and BaCe0.9Y0.1O3-δ were prepared through the conventional solid state reaction route. The chemical stability was investigated in hydrogen, carbon dioxide, and boiling water. Crystalline phase and microsa-ucture of the proton conductor before and after stability test were measured with X-ray diffraction （XRD） and scanning electron microscopy （SEM）, respectively. The results showed that all materials were quite stable in H2 atmosphere. In CO2 atmosphere, BaCe0.45Zr0.45M0.1O3-δ（M=Y, In） were relatively stable, while Bafe0.9Y0.1O3-δ decomposed. In boiling water, BaCe0.9Y0.1O3-δ was quickly decomposed into Ba（OH）2 and corresponding oxide. BaCe0.45Zr0.45M0.1O3-δ slightly reacted with boiling water and some amorphous phases were formed. However, BaCe0.45Zr0.45In0.1O3-δ was observed to exhibit better stability than BaCe0.45Zr0.45Y0.1O3-δ in water. The experimental results were interpreted in terms of thermodynamic data and tolerance factor.展开更多
The glass-forming region of B2O3-Al2O3-SiO2 （BAS） glass heavily doped with rare earth oxides was investigated by an effective method, and the chemical stability was investigated by powder method. Influences of rare ...The glass-forming region of B2O3-Al2O3-SiO2 （BAS） glass heavily doped with rare earth oxides was investigated by an effective method, and the chemical stability was investigated by powder method. Influences of rare earth oxides on the glass-forming ability and the chemical stability of the BAS glass were also discussed. The experimental results show that the BAS glass-forming region expands firstly with the increase of the Tb2O3 content up to 30mol% and then shrinks. The acid-resistant capacity of the BAS glass doped with rare earth oxides is the lowest, the water-resistant capacity is secondary, and the alkali-resistant capacity is the best. Besides, the glass chemical stability can be improved by doping appropriate amount of rare earth oxides. Moreover, the stronger the ionic polarization ability of the rare earth ions is, the better the chemical stability of the BAS glass will be.展开更多
Ba1.03Ce0.6Zr0.2Yb0.2O3-α ceramic was prepared by solid state reaction. Phase composition, surface and cross-section morphologies of the material were characterized by using X-ray diffractometer （XRD） and scanning ...Ba1.03Ce0.6Zr0.2Yb0.2O3-α ceramic was prepared by solid state reaction. Phase composition, surface and cross-section morphologies of the material were characterized by using X-ray diffractometer （XRD） and scanning electron microscopy （SEM）, respectively. Its chemical stability against carbon dioxide and water steam at high temperature was tested. Ionic conduction of the material was investigated by ac im-pedance spectroscopy and gas concentration cell methods under different gas atmospheres in the temperature range of 500-900 ℃. Using the ceramic as solid electrolyte and porous platinum as electrodes, the hydrogen-air fuel cell was constructed, and the cell performance at the tem-perature from 500 to 900 oC was examined. The results indicated that Ba1.03Ce0.6Zr0.2Yb0.2O3-α was a single-phase perovskite-type ortho-rhombic system, with high density and good chemical stability under carbon dioxide and water steam atmospheres at high temperature. In wet hydrogen, the material was a pure protonic conductor with the protonic transport number of 1 from 500 to 700 ℃, a mixed conductor of pro-ton and electron with the protonic transport numbers of 0.945-0.916 from 800 to 900 ℃. In wet air, the material was a mixed conductor of proton, oxide ion and electronic hole. The protonic transport numbers were 0.013-0.003, and the oxide ionic transport numbers were 0.346-0.265. Under hydrogen-air fuel cell conditions, the material was a mixed conductor of proton, oxide ion and electron, the ionic trans-port numbers were 0.945-0.848. The fuel cell could work stably, and at 900 ℃, the maximum power output density was 36.5 mW/cm^2.展开更多
SrCe0.92 Nb 0.03 Tm0.05 O 3-δ powders were synthesized by a modified sol-gel method using citrate as a chelating agent.X-ray diffraction（XRD） analysis verified SrCe 0.92 Nb 0.03 Tm 0.05 O 3-δ powders and membranes...SrCe0.92 Nb 0.03 Tm0.05 O 3-δ powders were synthesized by a modified sol-gel method using citrate as a chelating agent.X-ray diffraction（XRD） analysis verified SrCe 0.92 Nb 0.03 Tm 0.05 O 3-δ powders and membranes consisting of a single perovskite phase.The morphologies of the sintered membranes were investigated by using scanning electron microscopy（SEM） technique.Stability tests demonstrated that the Nb introduction into doped strontium cerate greatly enhanced the chemical stability.Electrical conductivities of SrCe 0.92 Nb 0.03 Tm 0.05 O 3-δ and SrCe 0.95 Tm 0.05 O 3-δ were measured by the four-point DC method under 10% H 2 /He atmosphere and temperatures（700-900℃）.With a maximum conductivity of 0.0067 S cm^-1 at 900℃,the total electrical conductivity of SrCe 0.92 Nb 0.03 Tm 0.05 O 3-δ increases with increasing temperature.The H 2 permeation flux of SrCe 0.92 Nb 0.03 Tm 0.05 O 3-δ is 0.035 mL cm-2 min-1 when 40% H 2 /He and Ar were used respectively as the feed and sweeping gases at 900℃.展开更多
The chemical stability of simulated waste forms Zr_（1–x）Nd_xSiO_（4–x/2） was investigated using the static leach test（MCC-1） with lixiviants of three pH values（pH=4, 6.7 and 10） at three temperature points（4...The chemical stability of simulated waste forms Zr_（1–x）Nd_xSiO_（4–x/2） was investigated using the static leach test（MCC-1） with lixiviants of three pH values（pH=4, 6.7 and 10） at three temperature points（40, 90 and 150 oC） for periods ranging from 1 to 42 d, and the influence of temperature, pH, as well as their combined effects were explored in detail. The results showed that all the normalized release rate of Nd firstly decreased with leaching time and closed to equilibrium after 14 d. As the temperature increased, the normalized release rate of Nd also increased, but it was no more than 3×10^（–5） g/（m^2·d）. And, the normalized release rate of Nd reached the highest values（~5×10^（–5） g/（m^2·d）） when pH=4, whilst the normalized release rate of Nd remained the lowest value（~1×10^（–5） g/（m^2·d）） near neutral environment（pH=6.7）.展开更多
Mixed Sn-Pb perovskites are attracting significant attention due to their narrow bandgap and consequent potential for all-perovskite tandem solar cells.However,the conventional hole transport materials can lead to ban...Mixed Sn-Pb perovskites are attracting significant attention due to their narrow bandgap and consequent potential for all-perovskite tandem solar cells.However,the conventional hole transport materials can lead to band misalignment or induce degradation at the buried interface of perovskite.Here we designed a self-assembled material 4-(9H-carbozol-9-yl)phenylboronic acid(4PBA)for the surface modification of the substrate as the hole-selective contact.It incorporates an electron-rich carbazole group and conjugated phenyl group,which contribute to a substantial interfacial dipole moment and tune the substrate’s energy levels for better alignment with the Sn-Pb perovskite energy levels,thereby promoting hole extraction.Meanwhile,enhanced perovskite crystallization and improved contact at bottom of the perovskite minimized defects within perovskite bulk and at the buried interface,suppressing non-radiative recombination.Consequently,Sn-Pb perovskite solar cells using 4PBA achieved efficiencies of up to 23.45%.Remarkably,the 4PBA layer provided superior interfacial chemical stability,and effectively mitigated device degradation.Unencapsulated devices retained 93.5%of their initial efficiency after 2000 h of shelf storage.展开更多
Halide solid-state electrolytes(SSEs)have become a new research focus for all-solid-state batteries because of their significant safety advantages,high ionic conductivity,high-voltage stability,and good ductility.None...Halide solid-state electrolytes(SSEs)have become a new research focus for all-solid-state batteries because of their significant safety advantages,high ionic conductivity,high-voltage stability,and good ductility.Nonetheless,stability issues are a key barrier to their practical application.In past reports,the analysis of halide electrolyte stability and its enhancement methods lacked relevance,which limited the design and optimization of halide solid electrolytes.This review focus on stability issues from a chemical,electrochemical,and interfacial point of view,with particular emphasis on the interaction of halide SSEs with anode and cathode interfaces.By focusing on innovative strategies to address the stability issue,this paper aims to further deepen the understanding and development of halide all-solid-state batteries by proposing to focus research efforts on improving their stability in order to address their inherent challenges and match higher voltage cathodes,paving the way for their wider application in the next generation of energy storage technologies.展开更多
Dense ceramic samples BaCe0.9-xZrxSm0.10O3-α （x=0.10, 0.15, 0.20, 0.30） were obtained by heat-treating the precursors prepared from a coprecipitation route. The phase structure, chemical stability and conduction be...Dense ceramic samples BaCe0.9-xZrxSm0.10O3-α （x=0.10, 0.15, 0.20, 0.30） were obtained by heat-treating the precursors prepared from a coprecipitation route. The phase structure, chemical stability and conduction behaviors of the ceramic samples have been investigated by X-ray powder diffraction and alternating current impedance spectroscopy methods. All the ceramic samples displayed a single phase of orthorhombic perovskite. The samples with x ≥0.20 were relatively stable after exposed to the flowing mixed gases： CO2 （φ=3%）＋H2O （φ=3%）＋N2 （φ= 94%） at 873 K for 12 h. Among the samples tested, the sample with x=0.20 exhibited both adequate conductivity and better chemical stability. The contribution of different charged species for x=0.20 sample to the conduction in wet hydrogen atmosphere was investigated by means of gas concentration cells. It was found that the sample of x= 0.20 was almost a pure ionic conductor, and the ionic conduction was contributed mainly by proton and partially by oxide ion in wet hydrogen atmosphere at 773--1073 K. The ammonia synthesis at atmospheric pressure in an electrolytic cell based on the sample of x=0.20 was successfully conducted and the peak ammonia formation rate achieved 2.67 × 10 ^-9 molos-locm 2 with direct current of 0.80 mA at 773 K.展开更多
<span style="font-family:Verdana;">Epilepsy is a chronic and the fourth most common neurological disorder which affects people of all age groups. Recently research and awareness on epilepsy-related dea...<span style="font-family:Verdana;">Epilepsy is a chronic and the fourth most common neurological disorder which affects people of all age groups. Recently research and awareness on epilepsy-related deaths have rapidly grown over the past two decades. Many previous studies are attributed to the guidelines that apprise health care professionals in handling these deaths, but there is a relative scarcity of information accessible for clinicians and pharmacists who are responsible for manufacturing or preparing the extemporaneous anti-epileptic suspensions in the hospitals. Mostly in partial seizures, phenytoin is one of the first-choice drugs. In Saudi Arabian hospitals, the extemporaneous preparation of phenytoin suspension is common, but the hot climatic weather in Saudi Arabia possesses stability problems that should be tackled as the prepared suspension should pass all the stability tests to ensure uniform dosage of the extemporaneous formulation. In the current study, the commercial capsules were used to prepare the oral phenytoin sodium extemporaneous suspension. The physical, chemical and microbiological stability of phenytoin sodium suspension is analyzed at various temperatures.</span>展开更多
Polyimides are a family of high-tech plastics that have irreplaceable applications in the fields of aerospace,defense,and opto-electronics,but polyimides are difficult to be reprocessed and recycled at the end of thei...Polyimides are a family of high-tech plastics that have irreplaceable applications in the fields of aerospace,defense,and opto-electronics,but polyimides are difficult to be reprocessed and recycled at the end of their service life,resulting in a significant waste of resources.Hence,it is of great significance to develop recyclable polyimides with comparable properties to the commercial products.Herein,we report a novel polymer-to-monomers chemically recyclable poly(imide-imine)(PtM-CR-PII)plastic,synthesized by cross-linking the amine-terminated aromatic bisimide monomer and the hexa-vanillin terminated cyclophosphazene monomer via dynamic imine bonds.The PtM-CR-PII plastic exhibits comparable mechanical and thermal properties as well as chemical stability to the commercial polyimides.The PtM-CR-PII plastic possesses a high Young’s modulus of≈3.2 GPa and a tensile strength as high as≈108 MPa,which also exhibits high thermal stability with a glass transition temperature of≈220℃.Moreover,the PtM-CR-PII plastic exhibits outstanding waterproofness,acid/alkali-resistance,and solvent-resistance,its appearance and mechanical properties can be well maintained after long-term soaking in water,highly concentrated acid and base,and various organic solvents.Furthermore,the cyclophosphazene moieties endow the PtM-CR-PII plastic with excellent flame retardancy.The PtM-CR-PII plastic exhibits the highest UL-94 flame-retarding rating of V-0 and a limiting oxygen index(LOI)value of 45.5%.Importantly,the PtM-CR-PII plastic can be depolymerized in an organic solvents-acid mixture medium at room temperature,allowing easy separation and recovery of both monomers in high purity.The recovered pure monomers can be used to regenerate new PtM-CR-PII plastics,enabling sustainable polymer-monomers-polymer circulation.展开更多
For characteristics of open and far from thermodynamic equilibrium in welding chemical reaction, a new kind of quantitative method, which is used to analyze direction and extent for chemical reaction of SiO2/Fe during...For characteristics of open and far from thermodynamic equilibrium in welding chemical reaction, a new kind of quantitative method, which is used to analyze direction and extent for chemical reaction of SiO2/Fe during quasi-steady state period, is introduced with the concept of non-equilibrium stationary state. The main idea is based on thermodynamic driving forces, which result in non-zero thermodynamic fluxes and lead to chemical reaction far away from thermodynamic equilibrium. There exists certain dynamic equilibrium relationship between rates of diffusion fluxes in liquid phase of reactants or products and the rate equation of chemical reaction when welding is in quasi-steady state. As result of this, a group of non-linear equations containing concentrations of all substances at interface of slag/liquid-metal may be established. Moreover the stability of this non-equilibrium stationary state is discussed using dissipative structure theory and it is concluded theoretically that this non-equilibrium stationary state for welding chemical reaction is of stability.展开更多
Protonic ceramic fuel cells(PCFCs) are promising for efficient,clean energy conversion at low to intermediate temperatures,but the widely used BaZr_(0.1)-Ce_(0.7)Y_(0.1)Yb_(0.1)O_(3-δ)(BZCYYb) electrolyte has poor ch...Protonic ceramic fuel cells(PCFCs) are promising for efficient,clean energy conversion at low to intermediate temperatures,but the widely used BaZr_(0.1)-Ce_(0.7)Y_(0.1)Yb_(0.1)O_(3-δ)(BZCYYb) electrolyte has poor chemical stability in humid environments.Herein,we show that under oxygen reduction reaction(ORR) conditions,water accumulates at the BaGd_(0.8)La_(0.2)Co_(2)O_(6-δ)(BGLC)cathode-BZCYYb electrolyte interface,causing selective loss of B a cations and decomposition of BZCYYb electrolyte.The introduction of triply ion-electron conducting La_(2)Ce_(2)O_(7-δ)(LCeO) into the BGLC cathode expands its active reaction area,accelerates ORR kinetics,and suppresses water accumulation at the cathode-electrolyte interface and electrolyte decomposition.A single cell with the BGLC-LCeO composite cathode achieves a peak power density of 1.07 W cm^(-2)at 700℃,with no profound degradation at 0.5 A cm^(-2)over 100 h.These findings provide guidance for the development of high-performance,durable PCFCs.展开更多
The widespread use of water-repellent superhydrophobic surfaces is limited by the inherent fragility of their micro-and nanoscale roughness, which is prone to damage and degradation. Here, we report a non-fluorinated ...The widespread use of water-repellent superhydrophobic surfaces is limited by the inherent fragility of their micro-and nanoscale roughness, which is prone to damage and degradation. Here, we report a non-fluorinated volumetric superhydrophobic nanocomposites that demonstrate mechanochemical robustness. The nanocomposites are produced through the addition of microscale diatomaceous earth and nanoscale fumed silica particles to high-temperature vulcanized silicone rubber. The water-repellency of the surface and bulk of nanocomposites having 120 phr of filler was determined based on the water contact angle and contact angle hysteresis. We compared the water-repellency of nanocomposites of differing diatomaceous earth to fumed silica mass ratios. Increasing the amount of diatomaceous earth enhanced the water-repellency of the nanocomposite surface, whereas an increased amount of fumed silica improved the water-repellency of the bulk material. Moreover, increasing the diatomaceous earth/fumed silica mass ratio improved the cross-linking density and hardness values of the nanocomposite.Despite being subjected to a range of mechanical durability tests, including sandpaper abrasion,knife scratching, tape peeling, water jet impact, and sandblasting, the nanocomposite maintained a water contact angle of 163. and contact angle hysteresis of 2°. When the water-repellency of the prepared nanocomposites eventually deteriorated, we restored their superhydrophobicity by removing the upper surface of the nanocomposite. This extraordinary robustness stems from the embedded low surface energy micro/nanostructures distributed throughout the nanocomposite. We also demonstrated the chemical stability, UV resistance, and self-cleaning abilities of the nanocomposite to illustrate the potential for real-life applications of this material.展开更多
A new two-dimensional atomic crystal, monolayer cuprous telluride（Cu2Te） has been fabricated on a grapheneSi C（0001） substrate by molecular beam epitaxy（MBE）. The low-energy electron diffraction（LEED） characte...A new two-dimensional atomic crystal, monolayer cuprous telluride（Cu2Te） has been fabricated on a grapheneSi C（0001） substrate by molecular beam epitaxy（MBE）. The low-energy electron diffraction（LEED） characterization shows that the monolayer Cu2Te forms ■ superstructure with respect to the graphene substrate. The atomic structure of the monolayer Cu2Te is investigated through a combination of scanning tunneling microscopy（STM） experiments and density functional theory（DFT） calculations. The stoichiometry of the Cu2Te sample is verified by x-ray photoelectron spectroscopy（XPS） measurement. The angle-resolved photoemission spectroscopy（ARPES） data present the electronic band structure of the sample, which is in good agreement with the calculated results. Furthermore, air-exposure experiments reveal the chemical stability of the monolayer Cu2Te. The fabrication of this new 2D material with a particular structure may bring new physical properties for future applications.展开更多
Y-Si compounds with the composition of Y:Si = 1:2 were fabricated using Yttrium and Silicon raw powders with low and high purity in various atmospheres and temperatures. Although the latest Y-Si phase diagram shows th...Y-Si compounds with the composition of Y:Si = 1:2 were fabricated using Yttrium and Silicon raw powders with low and high purity in various atmospheres and temperatures. Although the latest Y-Si phase diagram shows that the α- and β-YSi<sub>2</sub> phases are the stable phases for the stoichiometric composition of Y:Si = 1:2, the current experimental results suggest that the high temperature phase with the hexagonal structure, β-Y<sub>3</sub>Si<sub>5</sub>, would be the stable phase for this composition, and that the high temperature phase with the orthorhombic structure, β-YSi<sub>2</sub>, would be the meta-stable phase with high oxygen impurity content. It was demonstrated that YSi<sub>2</sub> powders possess much superior chemical stability than Yttrium metal. It was found that the best dispersing solvent was 2-propanol for YSi<sub>2</sub> powder.展开更多
Source water reservoirs easily become thermally and dynamically stratified.Internal pollution released from reservoir sediments is the main cause of water quality problems.To mitigate the internal pollution more effec...Source water reservoirs easily become thermally and dynamically stratified.Internal pollution released from reservoir sediments is the main cause of water quality problems.To mitigate the internal pollution more effectively,a new method,which combined chemical stabilization with water lifting aerator(WLA)technology,was proposed and its effciency in inhibiting pollutant release was studied by controlled sediment-water interface experiments.The results showed that this new method can inhibit pollutant release from sediment effectively.The values of mean effciency(E)in different reactors 2#–5#(1#with no agent,2#10 mg/L polymeric aluminum chloride(PAC)was added,3#20 mg/L PAC was added,4#30 mg/L PAC was added,5#20 mg/L PAC and 0.2 mg/L palyacrylamide(PAM)were added)for PO_(4)^(3-)were 35.0%,43.9%,50.4%and 63.6%,respectively.This showed that the higher the PAC concentration was,the better the inhibiting effciency was,and PAM addition strengthened the inhibiting effciency significantly.For Fe^(2+),the corresponding values of E for the reactors 2#–5#were 22.9%,47.2%,34.3%and 46.2%,respectively.The inhibiting effect of PAC and PAM on Mn release remained positive for a relatively short time,about 10 days,and was not so effective as for PO_(4)^(3-)and Fe^(2+).The average effciencies in inhibiting the release of UV254 were 35.3%,25.9%,35.5%,38.9%and 39.5%for reactors 2#–5#,respectively.The inhibiting mechanisms of the agents for different pollutants varied among the conditions and should be studied further.展开更多
基金supported by the National Natural Science Foundation of China(Nos.22171102 and 22090044)the National Key R&D Program of China(Nos.2021YFF0500502 and 2023YFA1506304)+2 种基金the Jilin Province Science and Technology Development Plan(No.20230101024JC)the"Medicine+X"crossinnovation team of Bethune Medical Department of Jilin University"Leading the Charge with Open Competition"construction project(No.2022JBGS04)the Jilin University Graduate Training Office(Nos.2021JGZ08 and 2022YJSJIP20).
文摘Solid-state electrolytes(SSEs),as the core component within the next generation of key energy storage technologies-solid-state lithium batteries(SSLBs)-are significantly leading the development of future energy storage systems.Among the numerous types of SSEs,inorganic oxide garnet-structured superionic conductors Li7La3Zr2O12(LLZO)crystallized with the cubic Iaˉ3d space group have received considerable attention owing to their highly advantageous intrinsic properties encompassing reasonable lithium-ion conductivity,wide electrochemical voltage window,high shear modulus,and excellent chemical stability with electrodes.However,no SSEs possess all the properties necessary for SSLBs,thus both the ionic conductivity at room temperature and stability in ambient air regarding cubic garnet-based electrolytes are still subject to further improvement.Hence,this review comprehensively covers the nine key structural factors affecting the ion conductivity of garnet-based electrolytes comprising Li concentration,Li vacancy concentration,Li carrier concentration and mobility,Li occupancy at available sites,lattice constant,triangle bottleneck size,oxygen vacancy defects,and Li-O bonding interactions.Furthermore,the general illustration of structures and fundamental features being crucial to chemical stability is examined,including Li concentration,Li-site occupation behavior,and Li-O bonding interactions.Insights into the composition-structure-property relations among cubic garnet-based oxide ionic conductors from the perspective of their crystal structures,revealing the potential compatibility conflicts between ionic transportation and chemical stability resulting from Li-O bonding interactions.We believe that this review will lay the foundation for future reasonable structural design of oxide-based or even other types of superionic conductors,thus assisting in promoting the rapid development of alternative green and sustainable technologies.
基金supported by the National Key Research and Development Program of China(2021YFB2500200)the National Natural Science Foundation of China(52177214,52222703)for supporting our workJiangsu Funding Program for Excellent Postdoctoral Talent for the support。
文摘Solid-state electrolytes with high oxidation stability are crucial for achieving high power density allsolid-state lithium batteries.Halide electrolytes are promising candidates due to their outstanding compatibility with cathode materials and high Li^(+)conductivity.However,the electrochemical stability of chloride electrolytes is still limited,leaving them unsuitable for ultrahigh voltage operation.Besides,chemical compatibility issue between sulfide and halide electrolytes affects the electrochemical performance of all-solid-state batteries.Herein,Li-ion conductor Li_(3+x)InCl_(6-x)O_(x) is designed to address these challenges.Li_(3.25)InCl_(5.75)O_(0.25)shows a Li-ion conductivity of 0.90 mS cm^(-1)at room temperature,a high onset oxidation voltage of 3.84 V,fewer by-products at ultrahigh operation voltage,and good chemical compatibility with Li_(5.5)PS_(4.5)Cl_(1.5).The Li_(3.25)InCl_(5.75)O_(0.25)@LiNi_(0.7)Co_(0.1)Mn_(0.2)O_(2)-Li_(3.25)InCl_(5.75)O_(0.25)-VGCF/Li_(3.25)InCl_(5.75)O_(0.25)/Li_(5.5)PS_(4.5)Cl_(1.5)/Li-In battery delivers good electrochemical performances at high operating voltage.This work provides a simple,economical,and effective strategy for designing high-voltage all-solid-state electrolytes.
文摘The phase composition, microstructure, thermal expansion coefficients, oxygen permeation properties and chemical stability of SrCo0.8Fe0.2O3-δ （SCFM） were investigated and compared with those of SrCo0.8Fe0.2O3-δ（SCF）. Single phase SCFM was successfully prepared by a combined EDTA-citric method. SCFM shows a lower thermal expansion coefficient （24× 10^-6-29× 10^-6/K） than SCF between 500 and 1050 ℃, indicating a more stable structure. SCFM shows a high oxygen permeation flux, although the oxygen flux of SCFM decreases slightly because of Mo dopant. Furthermore, it was demonstrated that the doping of Mo in SCF can prevent the order-disorder transition and improves the chemical stability to CO2.
基金Project supported by the National Natural Science Foundation of China(51672228)the Open Project of State Key Laboratory Cultivation Base for Nonmetal Composites and Functional Materials(11zxfk26)Science Development Foundation of China Academy of Engineering Physics
文摘In this study, Nd-bearing zirconolite-rich ceramics were prepared by solid-state reaction process using CaF2,ZrO2, Ti,TiO2, Fe2 O3 and Nd2O3 as the raw materials. Neodymium was used as trivalent actinide surrogate and designed to substitute the Ca and Zr sites of zirconolite with general stoichiometry of Ca1-xZr1-xNd2 xTi2O7（0≤x≤0.3）. Density of Fe-Nd-O sample reaches a maximum value of 4.13 g/cm^2 after being sintered at 1325 ℃ for 42 h. Three major phases, namely zirconolite, perovskite and pseudobrookite, are observed in all these samples. The EDX result shows that Nd2O3 can be successfully incorporated into the lattice structure of the prepared zirconolite-rich minerals and replace the Ca sites of zirconolite and perovskite with Fe3＋ as the charge-compensating ion. Furthermore, the thermal conductivities are all in the range of 1.51-1.67 W/（m·K）. The normalized elemental leaching rates of Ca and Nd in the Fe-Nd-0.2 sample keep in low values of 6.20 × 10^-2 and 4.86 × 10^-4 g/（m^2·d） after 42 d.
基金the National Natural Science Foundation of China (50772030, 50572024)
文摘BaCe0.45Zr0.45M0.1O3-δ （M=Y, In） and BaCe0.9Y0.1O3-δ were prepared through the conventional solid state reaction route. The chemical stability was investigated in hydrogen, carbon dioxide, and boiling water. Crystalline phase and microsa-ucture of the proton conductor before and after stability test were measured with X-ray diffraction （XRD） and scanning electron microscopy （SEM）, respectively. The results showed that all materials were quite stable in H2 atmosphere. In CO2 atmosphere, BaCe0.45Zr0.45M0.1O3-δ（M=Y, In） were relatively stable, while Bafe0.9Y0.1O3-δ decomposed. In boiling water, BaCe0.9Y0.1O3-δ was quickly decomposed into Ba（OH）2 and corresponding oxide. BaCe0.45Zr0.45M0.1O3-δ slightly reacted with boiling water and some amorphous phases were formed. However, BaCe0.45Zr0.45In0.1O3-δ was observed to exhibit better stability than BaCe0.45Zr0.45Y0.1O3-δ in water. The experimental results were interpreted in terms of thermodynamic data and tolerance factor.
文摘The glass-forming region of B2O3-Al2O3-SiO2 （BAS） glass heavily doped with rare earth oxides was investigated by an effective method, and the chemical stability was investigated by powder method. Influences of rare earth oxides on the glass-forming ability and the chemical stability of the BAS glass were also discussed. The experimental results show that the BAS glass-forming region expands firstly with the increase of the Tb2O3 content up to 30mol% and then shrinks. The acid-resistant capacity of the BAS glass doped with rare earth oxides is the lowest, the water-resistant capacity is secondary, and the alkali-resistant capacity is the best. Besides, the glass chemical stability can be improved by doping appropriate amount of rare earth oxides. Moreover, the stronger the ionic polarization ability of the rare earth ions is, the better the chemical stability of the BAS glass will be.
基金supported by the National Natural Science Foundation of China (20771079)Qing Lan and the Natural Science Foundation of Education Department of Jiangsu Province (07KJB150126)
文摘Ba1.03Ce0.6Zr0.2Yb0.2O3-α ceramic was prepared by solid state reaction. Phase composition, surface and cross-section morphologies of the material were characterized by using X-ray diffractometer （XRD） and scanning electron microscopy （SEM）, respectively. Its chemical stability against carbon dioxide and water steam at high temperature was tested. Ionic conduction of the material was investigated by ac im-pedance spectroscopy and gas concentration cell methods under different gas atmospheres in the temperature range of 500-900 ℃. Using the ceramic as solid electrolyte and porous platinum as electrodes, the hydrogen-air fuel cell was constructed, and the cell performance at the tem-perature from 500 to 900 oC was examined. The results indicated that Ba1.03Ce0.6Zr0.2Yb0.2O3-α was a single-phase perovskite-type ortho-rhombic system, with high density and good chemical stability under carbon dioxide and water steam atmospheres at high temperature. In wet hydrogen, the material was a pure protonic conductor with the protonic transport number of 1 from 500 to 700 ℃, a mixed conductor of pro-ton and electron with the protonic transport numbers of 0.945-0.916 from 800 to 900 ℃. In wet air, the material was a mixed conductor of proton, oxide ion and electronic hole. The protonic transport numbers were 0.013-0.003, and the oxide ionic transport numbers were 0.346-0.265. Under hydrogen-air fuel cell conditions, the material was a mixed conductor of proton, oxide ion and electron, the ionic trans-port numbers were 0.945-0.848. The fuel cell could work stably, and at 900 ℃, the maximum power output density was 36.5 mW/cm^2.
基金supported by Joint Funds of NSFC-Guangdong (No. U0834004)NSFC (No. 20976057)Guangdong Provincial Natural Science Funding (No. 06025657)
文摘SrCe0.92 Nb 0.03 Tm0.05 O 3-δ powders were synthesized by a modified sol-gel method using citrate as a chelating agent.X-ray diffraction（XRD） analysis verified SrCe 0.92 Nb 0.03 Tm 0.05 O 3-δ powders and membranes consisting of a single perovskite phase.The morphologies of the sintered membranes were investigated by using scanning electron microscopy（SEM） technique.Stability tests demonstrated that the Nb introduction into doped strontium cerate greatly enhanced the chemical stability.Electrical conductivities of SrCe 0.92 Nb 0.03 Tm 0.05 O 3-δ and SrCe 0.95 Tm 0.05 O 3-δ were measured by the four-point DC method under 10% H 2 /He atmosphere and temperatures（700-900℃）.With a maximum conductivity of 0.0067 S cm^-1 at 900℃,the total electrical conductivity of SrCe 0.92 Nb 0.03 Tm 0.05 O 3-δ increases with increasing temperature.The H 2 permeation flux of SrCe 0.92 Nb 0.03 Tm 0.05 O 3-δ is 0.035 mL cm-2 min-1 when 40% H 2 /He and Ar were used respectively as the feed and sweeping gases at 900℃.
基金Project supported by the National Natural Science Foundation of China(41302028,41302029,21507105)Thousand Youth Talents Plan(Y42H831301)+3 种基金Key Project of Sichuan Education Department(14ZA0099,15ZB0116)Foundation of Laboratory of National Defense Key Discipline for Nuclear Waste and Environmental Safety,Southwest University of Science and Technology(15yyhk10)the Doctor Foundation in Southwest University of Science and Technology(10zx7126)Hebei Science and Technology Support Program(15211121)
文摘The chemical stability of simulated waste forms Zr_（1–x）Nd_xSiO_（4–x/2） was investigated using the static leach test（MCC-1） with lixiviants of three pH values（pH=4, 6.7 and 10） at three temperature points（40, 90 and 150 oC） for periods ranging from 1 to 42 d, and the influence of temperature, pH, as well as their combined effects were explored in detail. The results showed that all the normalized release rate of Nd firstly decreased with leaching time and closed to equilibrium after 14 d. As the temperature increased, the normalized release rate of Nd also increased, but it was no more than 3×10^（–5） g/（m^2·d）. And, the normalized release rate of Nd reached the highest values（~5×10^（–5） g/（m^2·d）） when pH=4, whilst the normalized release rate of Nd remained the lowest value（~1×10^（–5） g/（m^2·d）） near neutral environment（pH=6.7）.
基金supported by the Joint Fund of Provincial Science and Technology Research and Development Plan of Henan Province(232301420004)and the Outstanding Youth Fund of the Natural Science Foundation of Henan Province(242300421069)the Energy for future-E4F Postdoctoral fellowship program MSCA-COFUND(101034297).
文摘Mixed Sn-Pb perovskites are attracting significant attention due to their narrow bandgap and consequent potential for all-perovskite tandem solar cells.However,the conventional hole transport materials can lead to band misalignment or induce degradation at the buried interface of perovskite.Here we designed a self-assembled material 4-(9H-carbozol-9-yl)phenylboronic acid(4PBA)for the surface modification of the substrate as the hole-selective contact.It incorporates an electron-rich carbazole group and conjugated phenyl group,which contribute to a substantial interfacial dipole moment and tune the substrate’s energy levels for better alignment with the Sn-Pb perovskite energy levels,thereby promoting hole extraction.Meanwhile,enhanced perovskite crystallization and improved contact at bottom of the perovskite minimized defects within perovskite bulk and at the buried interface,suppressing non-radiative recombination.Consequently,Sn-Pb perovskite solar cells using 4PBA achieved efficiencies of up to 23.45%.Remarkably,the 4PBA layer provided superior interfacial chemical stability,and effectively mitigated device degradation.Unencapsulated devices retained 93.5%of their initial efficiency after 2000 h of shelf storage.
基金supported by the National Natural Science Foundation of China(nos.22309027 and 52374301)the Shijiazhuang Basic Research Project(nos.241790667A and 241790907A)+3 种基金the Fundamental Research Funds for the Central Universities(no.N2523050)the Natural Science Foundation of Hebei Province(no.E2024501010)the Performance subsidy fund for Key Laboratory of Dielectric and Electrolyte Functional Material Hebei Province(no.22567627H)the 2024 Hebei Provincial Postgraduate Student Innovation Ability Training Funding Project(no.CXZZSS2025162)。
文摘Halide solid-state electrolytes(SSEs)have become a new research focus for all-solid-state batteries because of their significant safety advantages,high ionic conductivity,high-voltage stability,and good ductility.Nonetheless,stability issues are a key barrier to their practical application.In past reports,the analysis of halide electrolyte stability and its enhancement methods lacked relevance,which limited the design and optimization of halide solid electrolytes.This review focus on stability issues from a chemical,electrochemical,and interfacial point of view,with particular emphasis on the interaction of halide SSEs with anode and cathode interfaces.By focusing on innovative strategies to address the stability issue,this paper aims to further deepen the understanding and development of halide all-solid-state batteries by proposing to focus research efforts on improving their stability in order to address their inherent challenges and match higher voltage cathodes,paving the way for their wider application in the next generation of energy storage technologies.
基金Project supported by the National Natural Science Foundation of China （No. 20771079）.
文摘Dense ceramic samples BaCe0.9-xZrxSm0.10O3-α （x=0.10, 0.15, 0.20, 0.30） were obtained by heat-treating the precursors prepared from a coprecipitation route. The phase structure, chemical stability and conduction behaviors of the ceramic samples have been investigated by X-ray powder diffraction and alternating current impedance spectroscopy methods. All the ceramic samples displayed a single phase of orthorhombic perovskite. The samples with x ≥0.20 were relatively stable after exposed to the flowing mixed gases： CO2 （φ=3%）＋H2O （φ=3%）＋N2 （φ= 94%） at 873 K for 12 h. Among the samples tested, the sample with x=0.20 exhibited both adequate conductivity and better chemical stability. The contribution of different charged species for x=0.20 sample to the conduction in wet hydrogen atmosphere was investigated by means of gas concentration cells. It was found that the sample of x= 0.20 was almost a pure ionic conductor, and the ionic conduction was contributed mainly by proton and partially by oxide ion in wet hydrogen atmosphere at 773--1073 K. The ammonia synthesis at atmospheric pressure in an electrolytic cell based on the sample of x=0.20 was successfully conducted and the peak ammonia formation rate achieved 2.67 × 10 ^-9 molos-locm 2 with direct current of 0.80 mA at 773 K.
文摘<span style="font-family:Verdana;">Epilepsy is a chronic and the fourth most common neurological disorder which affects people of all age groups. Recently research and awareness on epilepsy-related deaths have rapidly grown over the past two decades. Many previous studies are attributed to the guidelines that apprise health care professionals in handling these deaths, but there is a relative scarcity of information accessible for clinicians and pharmacists who are responsible for manufacturing or preparing the extemporaneous anti-epileptic suspensions in the hospitals. Mostly in partial seizures, phenytoin is one of the first-choice drugs. In Saudi Arabian hospitals, the extemporaneous preparation of phenytoin suspension is common, but the hot climatic weather in Saudi Arabia possesses stability problems that should be tackled as the prepared suspension should pass all the stability tests to ensure uniform dosage of the extemporaneous formulation. In the current study, the commercial capsules were used to prepare the oral phenytoin sodium extemporaneous suspension. The physical, chemical and microbiological stability of phenytoin sodium suspension is analyzed at various temperatures.</span>
基金supported by Natural Science Foundation of Jilin Province(No.***202302003)the National Natural Science Foundation of China(No.22275069)National Key R&D Program of China(No.2023YFA1008804)。
文摘Polyimides are a family of high-tech plastics that have irreplaceable applications in the fields of aerospace,defense,and opto-electronics,but polyimides are difficult to be reprocessed and recycled at the end of their service life,resulting in a significant waste of resources.Hence,it is of great significance to develop recyclable polyimides with comparable properties to the commercial products.Herein,we report a novel polymer-to-monomers chemically recyclable poly(imide-imine)(PtM-CR-PII)plastic,synthesized by cross-linking the amine-terminated aromatic bisimide monomer and the hexa-vanillin terminated cyclophosphazene monomer via dynamic imine bonds.The PtM-CR-PII plastic exhibits comparable mechanical and thermal properties as well as chemical stability to the commercial polyimides.The PtM-CR-PII plastic possesses a high Young’s modulus of≈3.2 GPa and a tensile strength as high as≈108 MPa,which also exhibits high thermal stability with a glass transition temperature of≈220℃.Moreover,the PtM-CR-PII plastic exhibits outstanding waterproofness,acid/alkali-resistance,and solvent-resistance,its appearance and mechanical properties can be well maintained after long-term soaking in water,highly concentrated acid and base,and various organic solvents.Furthermore,the cyclophosphazene moieties endow the PtM-CR-PII plastic with excellent flame retardancy.The PtM-CR-PII plastic exhibits the highest UL-94 flame-retarding rating of V-0 and a limiting oxygen index(LOI)value of 45.5%.Importantly,the PtM-CR-PII plastic can be depolymerized in an organic solvents-acid mixture medium at room temperature,allowing easy separation and recovery of both monomers in high purity.The recovered pure monomers can be used to regenerate new PtM-CR-PII plastics,enabling sustainable polymer-monomers-polymer circulation.
基金This project is supported by National Natural Science Foundation of China(No. 50544025)Natural Science Foundation of High Education of Jiangsu Province, China (No. 05KJB460030)
文摘For characteristics of open and far from thermodynamic equilibrium in welding chemical reaction, a new kind of quantitative method, which is used to analyze direction and extent for chemical reaction of SiO2/Fe during quasi-steady state period, is introduced with the concept of non-equilibrium stationary state. The main idea is based on thermodynamic driving forces, which result in non-zero thermodynamic fluxes and lead to chemical reaction far away from thermodynamic equilibrium. There exists certain dynamic equilibrium relationship between rates of diffusion fluxes in liquid phase of reactants or products and the rate equation of chemical reaction when welding is in quasi-steady state. As result of this, a group of non-linear equations containing concentrations of all substances at interface of slag/liquid-metal may be established. Moreover the stability of this non-equilibrium stationary state is discussed using dissipative structure theory and it is concluded theoretically that this non-equilibrium stationary state for welding chemical reaction is of stability.
基金financially supported by the National Natural Science Foundation of China(Nos.22279018 and 22005055)
文摘Protonic ceramic fuel cells(PCFCs) are promising for efficient,clean energy conversion at low to intermediate temperatures,but the widely used BaZr_(0.1)-Ce_(0.7)Y_(0.1)Yb_(0.1)O_(3-δ)(BZCYYb) electrolyte has poor chemical stability in humid environments.Herein,we show that under oxygen reduction reaction(ORR) conditions,water accumulates at the BaGd_(0.8)La_(0.2)Co_(2)O_(6-δ)(BGLC)cathode-BZCYYb electrolyte interface,causing selective loss of B a cations and decomposition of BZCYYb electrolyte.The introduction of triply ion-electron conducting La_(2)Ce_(2)O_(7-δ)(LCeO) into the BGLC cathode expands its active reaction area,accelerates ORR kinetics,and suppresses water accumulation at the cathode-electrolyte interface and electrolyte decomposition.A single cell with the BGLC-LCeO composite cathode achieves a peak power density of 1.07 W cm^(-2)at 700℃,with no profound degradation at 0.5 A cm^(-2)over 100 h.These findings provide guidance for the development of high-performance,durable PCFCs.
基金the Natural Sciences and Engineering Research Council of Canada (NSERC)K-Line Insulators Limited (Toronto, Canada) for financial support。
文摘The widespread use of water-repellent superhydrophobic surfaces is limited by the inherent fragility of their micro-and nanoscale roughness, which is prone to damage and degradation. Here, we report a non-fluorinated volumetric superhydrophobic nanocomposites that demonstrate mechanochemical robustness. The nanocomposites are produced through the addition of microscale diatomaceous earth and nanoscale fumed silica particles to high-temperature vulcanized silicone rubber. The water-repellency of the surface and bulk of nanocomposites having 120 phr of filler was determined based on the water contact angle and contact angle hysteresis. We compared the water-repellency of nanocomposites of differing diatomaceous earth to fumed silica mass ratios. Increasing the amount of diatomaceous earth enhanced the water-repellency of the nanocomposite surface, whereas an increased amount of fumed silica improved the water-repellency of the bulk material. Moreover, increasing the diatomaceous earth/fumed silica mass ratio improved the cross-linking density and hardness values of the nanocomposite.Despite being subjected to a range of mechanical durability tests, including sandpaper abrasion,knife scratching, tape peeling, water jet impact, and sandblasting, the nanocomposite maintained a water contact angle of 163. and contact angle hysteresis of 2°. When the water-repellency of the prepared nanocomposites eventually deteriorated, we restored their superhydrophobicity by removing the upper surface of the nanocomposite. This extraordinary robustness stems from the embedded low surface energy micro/nanostructures distributed throughout the nanocomposite. We also demonstrated the chemical stability, UV resistance, and self-cleaning abilities of the nanocomposite to illustrate the potential for real-life applications of this material.
基金Project supported by the National Key Research&Development Program of China(Grant Nos.2016YFA0202300 and 2018YF A0305800)the National Natural Science Foundation of China(Grant Nos.61888102,11604373,61622116,and 51872284)+2 种基金the CAS Pioneer Hundred Talents Program,China,the Strategic Priority Research Program of Chinese Academy of Sciences(Grant Nos.XDB30000000 and XDB28000000)Beijing Nova Program,China(Grant No.Z181100006218023)the University of Chinese Academy of Sciences
文摘A new two-dimensional atomic crystal, monolayer cuprous telluride（Cu2Te） has been fabricated on a grapheneSi C（0001） substrate by molecular beam epitaxy（MBE）. The low-energy electron diffraction（LEED） characterization shows that the monolayer Cu2Te forms ■ superstructure with respect to the graphene substrate. The atomic structure of the monolayer Cu2Te is investigated through a combination of scanning tunneling microscopy（STM） experiments and density functional theory（DFT） calculations. The stoichiometry of the Cu2Te sample is verified by x-ray photoelectron spectroscopy（XPS） measurement. The angle-resolved photoemission spectroscopy（ARPES） data present the electronic band structure of the sample, which is in good agreement with the calculated results. Furthermore, air-exposure experiments reveal the chemical stability of the monolayer Cu2Te. The fabrication of this new 2D material with a particular structure may bring new physical properties for future applications.
文摘Y-Si compounds with the composition of Y:Si = 1:2 were fabricated using Yttrium and Silicon raw powders with low and high purity in various atmospheres and temperatures. Although the latest Y-Si phase diagram shows that the α- and β-YSi<sub>2</sub> phases are the stable phases for the stoichiometric composition of Y:Si = 1:2, the current experimental results suggest that the high temperature phase with the hexagonal structure, β-Y<sub>3</sub>Si<sub>5</sub>, would be the stable phase for this composition, and that the high temperature phase with the orthorhombic structure, β-YSi<sub>2</sub>, would be the meta-stable phase with high oxygen impurity content. It was demonstrated that YSi<sub>2</sub> powders possess much superior chemical stability than Yttrium metal. It was found that the best dispersing solvent was 2-propanol for YSi<sub>2</sub> powder.
基金supported by the Major Science and Technology Program for Water Pollution Control and Treatment(No.2009ZX07424-006)the National Natural Science Foundation of China(No.50830303)the Program for Changjiang Scholars and Innovative Research Team in University of MOE of China(PCSIRT)(No.IRT0853)
文摘Source water reservoirs easily become thermally and dynamically stratified.Internal pollution released from reservoir sediments is the main cause of water quality problems.To mitigate the internal pollution more effectively,a new method,which combined chemical stabilization with water lifting aerator(WLA)technology,was proposed and its effciency in inhibiting pollutant release was studied by controlled sediment-water interface experiments.The results showed that this new method can inhibit pollutant release from sediment effectively.The values of mean effciency(E)in different reactors 2#–5#(1#with no agent,2#10 mg/L polymeric aluminum chloride(PAC)was added,3#20 mg/L PAC was added,4#30 mg/L PAC was added,5#20 mg/L PAC and 0.2 mg/L palyacrylamide(PAM)were added)for PO_(4)^(3-)were 35.0%,43.9%,50.4%and 63.6%,respectively.This showed that the higher the PAC concentration was,the better the inhibiting effciency was,and PAM addition strengthened the inhibiting effciency significantly.For Fe^(2+),the corresponding values of E for the reactors 2#–5#were 22.9%,47.2%,34.3%and 46.2%,respectively.The inhibiting effect of PAC and PAM on Mn release remained positive for a relatively short time,about 10 days,and was not so effective as for PO_(4)^(3-)and Fe^(2+).The average effciencies in inhibiting the release of UV254 were 35.3%,25.9%,35.5%,38.9%and 39.5%for reactors 2#–5#,respectively.The inhibiting mechanisms of the agents for different pollutants varied among the conditions and should be studied further.
