The rapid advancement of modern science and technology,coupled with the recent surge in new-energy electric vehicles,has significantly boosted the demand for lithium.This has promoted the development and efficient uti...The rapid advancement of modern science and technology,coupled with the recent surge in new-energy electric vehicles,has significantly boosted the demand for lithium.This has promoted the development and efficient utilization of lepidolite as a lithium source.Therefore,the processes for the flotation of lepidolite have been studied in depth,particularly the development and use of lepidolite flotation collectors and the action mechanism of the collectors on the lepidolite surface.Based on the crystal-structure characteristics of lepidolite minerals,this review focuses on the application of anionic collectors,amine cationic collectors(primary amines,quaternary ammonium salts,ether amines,and Gemini amines),and combined collectors to the flotation behavior of lepidolite as well as the adsorption mechanisms.New directions and technologies for the controllable flotation of lepidolite are proposed,including process improvement,reagent synthesis,and mechanistic research.This analysis demonstrates the need for the further study of the complex environment inside lepidolite and pulp.By using modern analytical detection methods and quantum chemical calculations,research on reagents for the flotation of lepidolite has expanded,providing new concepts and references for the efficient flotation recovery and utilization of lepidolite.展开更多
Background:Home accessibility modifi cations are crucial for promoting independent living and quality of life among persons with disabilities.While developed countries have established comprehensive policy frameworks,...Background:Home accessibility modifi cations are crucial for promoting independent living and quality of life among persons with disabilities.While developed countries have established comprehensive policy frameworks,developing nations like China face unique challenges in program design and implementation.Objective:This study conducts a systematic comparative analysis of home accessibility modification policies across China,Japan,Germany,and Sweden,identifying key policy dimensions and proposing evidence-based recommendations for strengthening China’s policy framework.Methods:We employed a multi-dimensional analytical framework examining legislative foundations,eligibility criteria,funding mechanisms,and service delivery models.Data were collected from primary legislation,governmental regulations,official statistics,and peer-reviewed literature.Results:Significant cross-national variations exist in policy approaches.Japan and Germany utilize social insurance models with standardized assessments,Sweden adopts a universal rights-based approach,while China employs a targeted assistance model focused on economically disadvantaged households.China completed 1.28 million household renovations during its 14th Five-Year Plan,demonstrating strong implementation capacity;future policy refi nement could draw on international experience to strengthen assessment standardization,broaden eff ective coverage,and improve the sustainability of fi nancing.Conclusions:China can benefi t from international experience in developing standardized assessment protocols,diversifying funding mechanisms,and establishing professional service delivery systems,while acknowledging contextual constraints unique to developing country settings.展开更多
The scaling-up of electrochemical CO_(2)reduction requires circumventing the CO_(2)loss as carbonates under alkaline conditions.Zero-gap MEA cell configurations with a proton exchange membrane represent an alternative...The scaling-up of electrochemical CO_(2)reduction requires circumventing the CO_(2)loss as carbonates under alkaline conditions.Zero-gap MEA cell configurations with a proton exchange membrane represent an alternative solution in a pure acidic system,but the catalyst layer in direct contact with the hydrated proton environment usually leads to H_(2)evolution dominating.Herein,we show that polydimethyldiallyl-ammonium-chloride-coated Ag(Ag@PDDA)electrode exhibits outstanding performance with a FE of 86%,a single-pass conversion of 72%,and a stability of 28 h for CO production in pure-acid MEA compared with ammonium poly(N-methyl-piperidine-co-pterphenyl)decorated Ag(Ag/QAPPT)and cetyltrimethylammonium bromide decorated Ag(Ag/CTAB).The in situ ATR-SEIRAS reveal that PDDA creates a positive charge-rich protective outer layer and an N-rich hybrid inner layer,which not only suppresses the migration of H+during the electrolysis process and blocks the direct contact between H2O and Ag catalyst,but also promotes the generation from CO_(2)to*COOH in a pure-acid system.This work highlights the importance of polyelectrolyte engineering in regulating the electrocatalytic interface and accelerates the development of proton exchange membrane CO_(2)electrolysis.展开更多
The first-ever synthesis of the unknown furo[2,3:4,5]pyrimido[1,2-b]indazole skeleton was demonstrated based on the undiscovered tetra-functionalization of enaminones,with simple substrates and reaction conditions.The...The first-ever synthesis of the unknown furo[2,3:4,5]pyrimido[1,2-b]indazole skeleton was demonstrated based on the undiscovered tetra-functionalization of enaminones,with simple substrates and reaction conditions.The key to realizing this process lies in the multiple trapping of the in situ generated ketenimine cation by the 3-aminoindazole,which results in the formation of four new chemical bonds and two new rings in one pot.Moreover,the products of this new reaction were found to exhibit aggregationinduced emission(AIE)without modification.展开更多
In order to find the optimal anions and cations for designing energetic salts with excellent detonation properties,the properties of 140 salts formed from the anions(A–G)of 3,3′-dinitroamino-4,4′-azoxyfurazan(DAAF)...In order to find the optimal anions and cations for designing energetic salts with excellent detonation properties,the properties of 140 salts formed from the anions(A–G)of 3,3′-dinitroamino-4,4′-azoxyfurazan(DAAF)derivatives substituted with the—NH_(2),—N_(3) or—NO_(2) group and the cations(1–20)of guanidine,triazole,or tetrazole derivatives were investigated by means of density-functional theory.The predicted densities,heats of formation,detonation velocities(D),and detonation pressures(P)of 140 salts were 11.72 to 2.06 g·cm ^(−3),570.2 to 2333.4 kJ·mol^(−1),8.29 to 10.02 km·s^(−1) and 30.16 to 47.57 GPa,respectively.Most of the salts had better detonation properties than the widely used hexahydro-1,3,5-trinitro-1,3,5-triazine(RDX).Salts containing—NO_(2) group anions(C and F)have better detonation properties(D is 8.88 to 10.02 km·s^(−1) and P is 35.75 to 47.75 GPa)than other salts.Salts containing the cations NH_(4)^(+)(1),NH_(3)OH^(+)(2)and CH_(2)N_(4)NO_(2)^(+)(20)had good detonation properties(D is 9.38 to 10.02 km·s^(−1) and P is 40.72 to 47.75 GPa).Depending on the detonation properties,anions(C and F)and cations(1,2 and 20)are the recommended ions for the generation of energetic salts.展开更多
Incorporating organic bulky cations in the precursor or post-treatment to achieve two-dimensional/thr ee-dimensional(2D/3D)heterojunction is an effective strategy for enhancing the stability of perovskite materials.Ho...Incorporating organic bulky cations in the precursor or post-treatment to achieve two-dimensional/thr ee-dimensional(2D/3D)heterojunction is an effective strategy for enhancing the stability of perovskite materials.However,the issue of insufficient charge transport in 2D perovskites limits their development,and the fundamental mechanism of out-of-plane carrier transport remains unclear.This study designed and synthesized seven organic phenyl-core cations,differentiated at the 1-and 1,4-positions,and identified the impacts on the corresponding properties of the 2D crystalline perovskite.Shorter cations facilitated a more compact arrangement of adjacent inorganic layers,aligning to favor charge transport along the vertical direction.In addition,introducing high electronegativity led to increased intermolecular interactions,resulting in enhanced structural stability and improved phenyl ring π-orbital overlap and interlayer electron coupling,yielding efficient charge transport.Resilience to thermal stressing of the perovskite was strongly correlated with the carbon chain length of the spacer cations.The increase in cation length and the reduction in the rigidity of the amino-terminal both aided in the dispersion of thermal stress in the inorganic framework.Additional hydrogen bonding also contributed to mitigating structural disorder.展开更多
Transition metal carbonates(TMCs)hold great potential as high-performance electrodes for alkali metal-ion batteries,owing to multiple-ion storage mechanisms involving conversion process and electrocatalytic reaction.H...Transition metal carbonates(TMCs)hold great potential as high-performance electrodes for alkali metal-ion batteries,owing to multiple-ion storage mechanisms involving conversion process and electrocatalytic reaction.However,they still suffer from inferior electronic conductivity and volume variation during delithiation/lithiation.Heterostructure and heteroatoms doping offer immense promise in enhancing reaction kinetics and structural integrity,which unfortunately have not been achieved in TMCs.Herein,a unique TMCs heterostructure with Ni-doped MnCO_(3)as“core”and Mn-doped NiCO_(3)as“shell”,which is wrapped by graphene(NM@MN/RGO),is achieved by cations differentiation strategy.The formation process for core-shell NM@MN consists of epitaxial growth of NiCO_(3)from MnCO_(3)and synchronously mutual doping,owing to the similar crystal structures but different solubility product constant/formation energy of MnCO_(3)and NiCO_(3).In-situ electrochemical impedance spectroscopy,galvanostatic intermittent titration technique,differential capacity versus voltage plots,theoretical calculation and kinetic analysis reveal the superior electrochemical activity of the NM@MN/RGO to MnCO_(3)/RGO.The NM@MN/RGO shows excellent lithium storage properties(1013.4 mAh·g^(-1)at 0.1 A·g^(-1)and 760 mAh·g^(-1)after 1000 cycles at 2 A·g^(-1))and potassium storage properties(capacity decay rate of 0.114 mAh·g^(-1)per cycle).This work proposes an efficient cation differentiation strategy for constructing advanced TMC electrodes.展开更多
The investigation of thermal transport properties of materials has become increasingly important in technological applications,including thermal management and energy conversion.Recently,ultrahigh or low thermal condu...The investigation of thermal transport properties of materials has become increasingly important in technological applications,including thermal management and energy conversion.Recently,ultrahigh or low thermal conductivity has been reported in nitride,boride,and chalcogenide by different strategies.However,the strategy to design oxide crystals with unique thermal properties is also a challenge.In this work,a new ternary oxide crystal Ga_(2)TeO_(6) is designed and expected to show high thermal conductivity due to its lone pairs-free octahedra connected along the caxis by sharing edges.The thermal conductivities of Ga_(2)TeO_(6) crystal are determined to be 19.2 and 23.9Wm^(-1) K^(-1) along the a-and c-axis directions at 323 K,respectively,which are significantly higher than those of most reported oxide crystals.First-principles calculations and crystal structure analyses reveal that the Ga_(2)TeO_(6) crystal shows high sound velocity and weak lattice anharmonicity due to lone pairs-free octahedra and highly symmetric group arrangement.The results suggest that much attention must be paid to the polyhedron with lone pairs and its arrangement in materials design to balance the functions and thermal properties.展开更多
NiFe-layered double hydroxides(NiFe-LDHs)are among the most promising earth-abundant electrocatalysts for the oxygen evolution reaction(OER)in alkaline media.However,their practical application is hindered by intrinsi...NiFe-layered double hydroxides(NiFe-LDHs)are among the most promising earth-abundant electrocatalysts for the oxygen evolution reaction(OER)in alkaline media.However,their practical application is hindered by intrinsic activity limitations and poor stability,primarily due to the asymmetric adsorption of oxygen intermediates.To overcome this,the binding strength must be synergistically tuned to a moderate level to optimize catalytic performance.Here,we engineered NiFeCoCr LDH through Co doping to enhance electrical conductivity and controlled Cr leaching to introduce cationic vacancies for modulating intermediate binding strength in NiFe LDH.X-ray absorption near-edge structure and extended X-ray absorption fine structure analyses reveal that NiFe-LDH with Co doping and Cr vacancies modulates the Ni oxidation state and local coordination environment,leading to a balanced electronic structure and enhanced structural complexity around the Ni sites.Additionally,these vacancies can trap OH^(-)/H_(2)O species,which can serve as a reservoir for OH^(-) transfer,facilitating the rapid formation of OER intermediates and enhancing catalytic performance at high current densities.As a result,V_(Cr)-NiFeCo LDH achieves 1.6 A cm^(-2)current density at 1.7 V vs.RHE while maintaining stable operation for over 1000 h at 500 mA cm^(-2).Density functional theory(DFT)calculations validate the synergistic effects of Co doping and Cr-induced vacancies on intermediate binding energies and improved OER kinetics.Overall,this work presents a rational design strategy to simultaneously enhance the activity and durability of NiFe-based OER catalysts for their application in high-performance alkaline water electrolysis.展开更多
Phonon coherence can reflect electron‒phonon coupling information and has been proven to modulate electronic states and charge transport.The manipulation of phonon coherence through spacer cation engineering in organi...Phonon coherence can reflect electron‒phonon coupling information and has been proven to modulate electronic states and charge transport.The manipulation of phonon coherence through spacer cation engineering in organic‒inorganic hybrid perovskites(OIHPs)has been extensively demonstrated;however,the underlying structural origin remains elusive at the molecular level.Herein,we present molecular structure and temperature-dependent coherent phonon studies via a combination of sum frequency generation vibrational spectroscopy(SFG-VS)and transient absorption spectroscopy(TAS).The conformational order of spacer cations dictates the coherent phonon oscillations in 2D OIHPs.Our study further analyzes the static order and dynamic disorder in 2D perovskites.This work provides molecular-level insights into the role of spacer cations in tuning structural order and may provide valuable guidance for advancing emergent optoelecltronics development.展开更多
Mussels are common anchoring organisms that adhere to the surfaces of various substrates with their byssus.The adhesion of mussel to substrates is contingent upon the presence of mussel foot proteins,of which Mytilus ...Mussels are common anchoring organisms that adhere to the surfaces of various substrates with their byssus.The adhesion of mussel to substrates is contingent upon the presence of mussel foot proteins,of which Mytilus edulis foot protein-1(Mefp-1)has been identified as the most abundant protein.It has been found that lipids are involved in the mussel adhesion process and can facilitate Mefp-1adhesion.In this research,the adhesion behavior of Mefp-1 on various substrate surfaces under the effect of typical seawater cations with or without the presence of lipid were investigated using a quartz crystal microbalance with dissipation(QCM-D).Results indicate that the presence of cations Ca^(2+),Mg^(2+),Na^(+),and K^(+)leads to varying degrees of reduction in the adhesion performance of Mefp-1 on different substrates.The degree of this reduction,however,was much alleviated in the presence of palmitic acid,which is involved in the mussel adhesion process.Therefore,the involvement of palmitic acid is advantageous for mussel protein adhesion to the substrate surface in the marine environment.This study illustrated the significant contribution of palmitic acid to mussel adhesion,which can help to better understand biofouling mechanisms and develop biomimetic adhesive materials.展开更多
The development of synthetic hybrid biological systems integrating photosynthetic organisms with organic-abiotic functional materials holds significant promise for enhancing photosynthetic processes.The artificial reg...The development of synthetic hybrid biological systems integrating photosynthetic organisms with organic-abiotic functional materials holds significant promise for enhancing photosynthetic processes.The artificial regulation of the state transition between photosystem I(PSI)and photosystem II(PSII)represents a strategic and promising approach for improving the efficiency of natural photosynthesis.In this study,we demonstrate that poly(benzimidazolium-phenylthiophene)(CP4)featuring a flexible cationic backbone exhibits superior ultraviolet light-harvesting capability.The polymer CP4 enhanced PSI activity in Chlorella pyrenoidosa(C.pyrenoidosa),subsequently promoting PSII activity and augmenting overall photosynthetic performance.During light-dependent reactions,CP4 significantly accelerated photosynthetic electron transfer,resulting in a 330%increase in the production of oxygen and 93%and 96%increases in the ATP and NADPH contents,respectively.In the context of dark reactions,CP4 facilitated the conversion and utilization of light energy,leading to a 6%increase in both carbohydrate and protein contents.These findings indicate that synthetic light-harvesting polymer materials exhibit considerable application potential in the field of biomass production through enhancement of natural photosynthetic efficiency.展开更多
Cataract is the leading cause of reversible blindness worldwide,affecting millions,particularly the elderly.Over 65 million people suffer from significant visual impairment due to cataracts,with the burden being highe...Cataract is the leading cause of reversible blindness worldwide,affecting millions,particularly the elderly.Over 65 million people suffer from significant visual impairment due to cataracts,with the burden being highest in low-and middle-income countries where access to surgery is limited.Cataract surgery,one of the most commonly performed and cost-effective procedures,has evolved significantly.Traditional extracapsular cataract extraction(ECCE)has been largely replaced by phacoemulsifi cation,which uses ultrasonic energy through a small incision,reducing recovery time and complications.More recently,femtosecond laser-assisted cataract surgery(FLACS)has emerged,off ering enhanced precision but with ongoing evaluation of its cost-eff ectiveness.Intraocular lenses(IOLs)now allow for customized visual outcomes,addressing distance,near,and intermediate vision.Despite its safety,cataract surgery can still result in complications such as corneal edema and posterior capsular opacifi cation,requiring careful surgical management and patient education.展开更多
Sodium layered oxides stand out as one of the most promising cathodes for sodium-ion batteries due to their high energy density,elemental abundance,and scalability.However,their practical applications are restricted b...Sodium layered oxides stand out as one of the most promising cathodes for sodium-ion batteries due to their high energy density,elemental abundance,and scalability.However,their practical applications are restricted by interplanar gliding,cation migration,and the formation of intragranular microcracks,which collectively lead to rapid structural degradation and capacity loss.Herein,we rationally design an ultrastable O3-type Na_(0.94)Ca_(0.03)Ni_(1/3)Fe_(1/3)Mn_(1/3)O_(2) cathode,in which Ca^(2+)cations act as pillars within the NaO_(2)slabs,suppressing the irreversible phase transitions and Na/TM cation migration commonly observed in layered oxides.Multiscale in situ and ex situ techniques,combined with post-mortem analysis,reveal that the Ca-pillared pinning effect not only effectively suppresses the interplanar gliding and stress accumulation within the crystal phase but also restrains Na/TM cation migration and surface reconstruction in near-surface regions.Benefiting from the combined effects of structural stabilization,the Ca-pillared cathode exhibits a superior cycling stability,retaining 81.6%of its capacity after 1000 cycles at 2 C within the voltage range of 2.0-4.0 V,along with significantly enhanced wide-temperature(from-40 to 80℃)performance.This work highlights another critical role of Ca pillars in suppressing cation migration and surface structural degradation beyond preventing adverse interplanar gliding,offering valuable insights for designing long-life and wide-temperature layered oxide cathodes.展开更多
Converting CO_(2) into methanol(CH_(3)OH),a high-value-added liquid-phase product,through efficient and highly selective photocatalysis remains a significant challenge.Herein,we present a straightforward cation exchan...Converting CO_(2) into methanol(CH_(3)OH),a high-value-added liquid-phase product,through efficient and highly selective photocatalysis remains a significant challenge.Herein,we present a straightforward cation exchange strategy for the in-situ growth of BiVO_(4) on an InVO_(4) substrate to generate a Z-scheme heterojunction of InVO_(4)/BiVO_(4) .This in-situ partial transformation approach endows the InVO_(4)/BiVO_(4) heterojunction with a tightly connected interface,resulting in a significant improvement in charge separation efficiency between InVO_(4) and BiVO_(4).Moreover,the construction of the heterojunction reduces the formation energy barrier of the ^(*)COOH intermediate during the photoreduction of CO_(2) and increases the desorption energy barrier of the ^(*)CO intermediate,facilitating the deep reduction of ^(*)CO.Consequently,the InVO_(4)/BiVO_(4) heterojunction is capable of photocatalytic CO_(2) reduction to CH_(3)OH with high efficiency and selectivity.Under conditions where water serves as the electron source and a light intensity of 100 m W/cm^(2),the yield of CH_(3)OH reaches 130.5 μmol g^(-1)h^(-1) with a selectivity of 92 %,outperforming photocatalysts reported under similar conditions.展开更多
Aqueous zinc-ion batteries(AZIBs) have advantages including low economic cost and high safety.Nevertheless,the serious hydrogen evolution reactions(HER) and rampant growth of Zn dendrite hinder their further developme...Aqueous zinc-ion batteries(AZIBs) have advantages including low economic cost and high safety.Nevertheless,the serious hydrogen evolution reactions(HER) and rampant growth of Zn dendrite hinder their further development.Herein,potassium acetate(KAc) additive with cation/anion synergy effect is added into the ZnSO_(4) electrolyte to effectively promote the oriented uniform Zn deposition and suppress side reactions.According to density functional theory calculation and experimental results,CH_(3)COO^(-)(Ac^(-))anions are capable of forming stronger hydrogen bonds with H_(2)O molecules,leading to an expanded electrochemical stability window,reduced the reactivity of H_(2)O,and hence suppressing HER.Meanwhile,Ac-anions can also preferentially adsorb onto the Zn anode,promoting dense deposition towards the(100) crystal plane.Besides,dissociated K^(+) ions serve as electrostatic shielding cations,which significantly promote uniform Zn deposition and prevent dendrite formation.Thus,the Zn||Zn symmetric cell demonstrates an impressive cycle lifespan of 3000 h at 1.0 m A/cm^(2).Furthermore,the Zn||MnO_(2) full battery exhibits superior stability with a capacity retention of 86.95 % at 2.0 A/g after 4000 cycles.Therefore,the cation/anion synergy effect in KAc additive offers a viable solution to address HER and hinder dendrite growth at the interface of Zn anodes.展开更多
The mutual effects of metal cations （Cu2＋, Pb2＋, Zn2＋, and Cd2＋） and p-nitrophenol （NP） on their adsorption desorption behavior onto wheat ash were studied. Results suggested that Cu2＋, Pb2＋, and Zn2＋ dimin...The mutual effects of metal cations （Cu2＋, Pb2＋, Zn2＋, and Cd2＋） and p-nitrophenol （NP） on their adsorption desorption behavior onto wheat ash were studied. Results suggested that Cu2＋, Pb2＋, and Zn2＋ diminished the adsorption and increased the desorption of NP remarkably, while Cd2＋ had no such effect. In contrast, NP diminished the adsorption of Cu2＋, Pb2＋, and Zn2＋ onto ash, however, this suppression effect depended on the initial concentrations of metal cations. NP had no effect on Cd〉 adsorption on ash. Fourier transform infrared （FT-IR） and X-ray absorption spectroscopic （XAS） studies suggested the following mechanisms responsible for the metal suppression effect on NP adsorption： （1） large hydrated Cu2＋, Pb2＋, and Zn〉 shells occupied the surface of ash and prevent nonspecific adsorption of NP onto ash surface; （2） Cu2＋, Pb2＋, and Zn2＋ may block the micropores of ash, resulting in decreased adsorption of NP; （3） cornplexation of Cu2＋, Pb2＋, and Zn2＋ was likely via carboxyl, hydroxylic and phenolic groups of wheat ash and these same groups may also react with NP during adsorption. As a ＂soft acid＂, Cd2＋ is less efficient in the complexation of oxygencontaining acid groups than Cu2＋, Pb2＋, and Zn2＋. Thus, Cd2＋ had no effect on the adsorption of NP on wheat ash.展开更多
As a pioneer leguminous shrub species for vegetation re-establishment, Caragana microphylla is widely distributed in the semi-fixed and fixed sandy lands of the Horqin region, North China. C. microphylla planta- tions...As a pioneer leguminous shrub species for vegetation re-establishment, Caragana microphylla is widely distributed in the semi-fixed and fixed sandy lands of the Horqin region, North China. C. microphylla planta- tions modify organic carbon （SOC）, nitrogen （N） and phosphorus dynamics, bulk density and water-holding capacity and biological activities in soils, but little is known with regard to soil exchange properties. Variation in soil ex- changeable base cations was examined under C. microphylla plantations with an age sequence of 0, 5, 10, and 22 years in the Horqin Sandy Land, and at the depth of 0-10, 10-20, and 20-30 cm, respectively. C. microphylla has been planted on the non-vegetated sand dunes with similar physical-chemical soil properties. The results showed that exchangeable calcium （Ca）, magnesium （Mg）, and potassium （K）, and cation exchange capacity （CEC） were significantly increased, and Ca saturation tended to decrease, while Mg and K saturations were increased with the plantation years. No difference was observed for exchangeable sodium （Na） neither with plantation years nor at soil depths. Of all the base cations and soil layers, exchangeable K at the depth of 0-10 cm accumulated most quickly, and it increased by 1.76, 3.16, and 4.25 times, respectively after C. microphylla was planted for 5, 10, and 22 years. Exchangeable Ca, Mg, and K, and CEC were significantly （P〈0.001） and positively correlated with SOC, total N, pH and electrical conductivity （EC）. Soil pH and SOC are regarded as the main factors influencing the variation in ex- changeable cations, and the preferential absorption of cations by plants and different leaching rates of base cations that modify cation saturations under C. microphylla plantation. It is concluded that as a nitrogen-fixation species, C. microphylla plantation is beneficial to increasing exchangeable base cations and CEC in soils, and therefore can improve soil fertility and create favorable microenvironments for plants and creatures in the semi-arid sandy land ecosystems.展开更多
The effects of alkaline cations （M^＋ = Li^＋, Na^＋, K^＋, Cs^＋）on the electrochemical synthesis of polyaniline were carfled out under cyclovoltammetric conditions using nitrates of Li^＋, Na^＋, K^＋, and Cs^＋ a...The effects of alkaline cations （M^＋ = Li^＋, Na^＋, K^＋, Cs^＋）on the electrochemical synthesis of polyaniline were carfled out under cyclovoltammetric conditions using nitrates of Li^＋, Na^＋, K^＋, and Cs^＋ as the supporting electrolytes. The results show that the oxidation potentials of aniline in the electrolytes decrease as the protonation extent of aniline decreases from the fast scan, which is caused by the decrease of the ionic radius of alkaline metal ions at the same concentration of alkaline cations. With the scan number increasing, the deposit charge Q as the characteristic growth function also depends on the protonation of aniline, and it increases with the ionic radius of alkaline cations increasing. SEM images show the effect of alkaline cations on the morphology of polyaniline. It is clear that the ionic mobility of alkaline cations is further lower than that of W. Alkaline cations and counter-ions were the species responsible for the enhancement of Pani electrosynthesis. Therefore, this is exactly what SEM images show： a relatively rough fibrous structure in the case of Pani-H^＋ suggesting a sponge-like structure and a highly orderly fiber-like structure in the case of Pani-M^＋.展开更多
The effects of simulated nitrogen(N)deposition on soil exchangeable cations were studied in three forest types of subtropical China.Four N treatments with three replications were designed for the monsoon evergreen bro...The effects of simulated nitrogen(N)deposition on soil exchangeable cations were studied in three forest types of subtropical China.Four N treatments with three replications were designed for the monsoon evergreen broadleaf forest (mature forest):control(0 kg N ha-1 year-1),low N(50 kg N ha-1 year-1),medium N(100 kg N ha-1 year-1)and high N(150 kg N ha-1 year-1),and only three treatments(i.e.,control,low N,medium N)were established for the pine and mixed forests.Nitrogen had been applied continuously for 26 months before the measurement.The mature forest responded more rapidly and intensively to N additions than the pine and mixed forests,and exhibited some significant negative symptoms,e.g.,soil acidification,Al mobilization and leaching of base cations from soil.The pine and mixed forests responded slowly to N additions and exhibited no significant response of soil cations.Response of soil exchangeable cations to N deposition varied in the forests of subtropical China,depending on soil N status and land-use history.展开更多
基金financially supported by the Excellent Youth Scholars Program of State Key Laboratory of Complex Nonferrous Metal Resource Clean Utilization,Kunming University of Science and Technology,China(No.YXQN-2024003)the Central Government-Guided Local Science and Technology Development Fund Project,China(No.202407AB110022)。
文摘The rapid advancement of modern science and technology,coupled with the recent surge in new-energy electric vehicles,has significantly boosted the demand for lithium.This has promoted the development and efficient utilization of lepidolite as a lithium source.Therefore,the processes for the flotation of lepidolite have been studied in depth,particularly the development and use of lepidolite flotation collectors and the action mechanism of the collectors on the lepidolite surface.Based on the crystal-structure characteristics of lepidolite minerals,this review focuses on the application of anionic collectors,amine cationic collectors(primary amines,quaternary ammonium salts,ether amines,and Gemini amines),and combined collectors to the flotation behavior of lepidolite as well as the adsorption mechanisms.New directions and technologies for the controllable flotation of lepidolite are proposed,including process improvement,reagent synthesis,and mechanistic research.This analysis demonstrates the need for the further study of the complex environment inside lepidolite and pulp.By using modern analytical detection methods and quantum chemical calculations,research on reagents for the flotation of lepidolite has expanded,providing new concepts and references for the efficient flotation recovery and utilization of lepidolite.
基金funded by the China Disabled Persons’Federation under its 2024 research project(Grant No.2024CDPFAT-47)the Yancheng Social Science Foundation(Grant No.25skB252).
文摘Background:Home accessibility modifi cations are crucial for promoting independent living and quality of life among persons with disabilities.While developed countries have established comprehensive policy frameworks,developing nations like China face unique challenges in program design and implementation.Objective:This study conducts a systematic comparative analysis of home accessibility modification policies across China,Japan,Germany,and Sweden,identifying key policy dimensions and proposing evidence-based recommendations for strengthening China’s policy framework.Methods:We employed a multi-dimensional analytical framework examining legislative foundations,eligibility criteria,funding mechanisms,and service delivery models.Data were collected from primary legislation,governmental regulations,official statistics,and peer-reviewed literature.Results:Significant cross-national variations exist in policy approaches.Japan and Germany utilize social insurance models with standardized assessments,Sweden adopts a universal rights-based approach,while China employs a targeted assistance model focused on economically disadvantaged households.China completed 1.28 million household renovations during its 14th Five-Year Plan,demonstrating strong implementation capacity;future policy refi nement could draw on international experience to strengthen assessment standardization,broaden eff ective coverage,and improve the sustainability of fi nancing.Conclusions:China can benefi t from international experience in developing standardized assessment protocols,diversifying funding mechanisms,and establishing professional service delivery systems,while acknowledging contextual constraints unique to developing country settings.
基金financial support of the National Natural Science Foundation of China(NSFC)(52394202,52021004,52301232,and 52476056)the Natural Science Foundation of Chongqing Province(2024NSCQ-MSX1109).
文摘The scaling-up of electrochemical CO_(2)reduction requires circumventing the CO_(2)loss as carbonates under alkaline conditions.Zero-gap MEA cell configurations with a proton exchange membrane represent an alternative solution in a pure acidic system,but the catalyst layer in direct contact with the hydrated proton environment usually leads to H_(2)evolution dominating.Herein,we show that polydimethyldiallyl-ammonium-chloride-coated Ag(Ag@PDDA)electrode exhibits outstanding performance with a FE of 86%,a single-pass conversion of 72%,and a stability of 28 h for CO production in pure-acid MEA compared with ammonium poly(N-methyl-piperidine-co-pterphenyl)decorated Ag(Ag/QAPPT)and cetyltrimethylammonium bromide decorated Ag(Ag/CTAB).The in situ ATR-SEIRAS reveal that PDDA creates a positive charge-rich protective outer layer and an N-rich hybrid inner layer,which not only suppresses the migration of H+during the electrolysis process and blocks the direct contact between H2O and Ag catalyst,but also promotes the generation from CO_(2)to*COOH in a pure-acid system.This work highlights the importance of polyelectrolyte engineering in regulating the electrocatalytic interface and accelerates the development of proton exchange membrane CO_(2)electrolysis.
基金supported by the National Natural Science Foundation of China(Nos.21971080,22171098)supported by Chengdu Guibao Science&Technology Co.,Ltd.This work was also supported by the 111 Project(No.B17019)。
文摘The first-ever synthesis of the unknown furo[2,3:4,5]pyrimido[1,2-b]indazole skeleton was demonstrated based on the undiscovered tetra-functionalization of enaminones,with simple substrates and reaction conditions.The key to realizing this process lies in the multiple trapping of the in situ generated ketenimine cation by the 3-aminoindazole,which results in the formation of four new chemical bonds and two new rings in one pot.Moreover,the products of this new reaction were found to exhibit aggregationinduced emission(AIE)without modification.
文摘In order to find the optimal anions and cations for designing energetic salts with excellent detonation properties,the properties of 140 salts formed from the anions(A–G)of 3,3′-dinitroamino-4,4′-azoxyfurazan(DAAF)derivatives substituted with the—NH_(2),—N_(3) or—NO_(2) group and the cations(1–20)of guanidine,triazole,or tetrazole derivatives were investigated by means of density-functional theory.The predicted densities,heats of formation,detonation velocities(D),and detonation pressures(P)of 140 salts were 11.72 to 2.06 g·cm ^(−3),570.2 to 2333.4 kJ·mol^(−1),8.29 to 10.02 km·s^(−1) and 30.16 to 47.57 GPa,respectively.Most of the salts had better detonation properties than the widely used hexahydro-1,3,5-trinitro-1,3,5-triazine(RDX).Salts containing—NO_(2) group anions(C and F)have better detonation properties(D is 8.88 to 10.02 km·s^(−1) and P is 35.75 to 47.75 GPa)than other salts.Salts containing the cations NH_(4)^(+)(1),NH_(3)OH^(+)(2)and CH_(2)N_(4)NO_(2)^(+)(20)had good detonation properties(D is 9.38 to 10.02 km·s^(−1) and P is 40.72 to 47.75 GPa).Depending on the detonation properties,anions(C and F)and cations(1,2 and 20)are the recommended ions for the generation of energetic salts.
基金financially supported by the Key Fund Project of Tianjin Natural Science Foundation(24JCZDJC00510)the Fundamental Research Funds for the Central Universitiespartially supported by the U.S.Department of Energy under Contract No.DE-AC3608GO28308 with Alliance for Sustainable Energy,Limited Liability Company(LLC),the Manager and Operator of the National Renewable Energy Laboratory,through Grant No.DE-SC0020718。
文摘Incorporating organic bulky cations in the precursor or post-treatment to achieve two-dimensional/thr ee-dimensional(2D/3D)heterojunction is an effective strategy for enhancing the stability of perovskite materials.However,the issue of insufficient charge transport in 2D perovskites limits their development,and the fundamental mechanism of out-of-plane carrier transport remains unclear.This study designed and synthesized seven organic phenyl-core cations,differentiated at the 1-and 1,4-positions,and identified the impacts on the corresponding properties of the 2D crystalline perovskite.Shorter cations facilitated a more compact arrangement of adjacent inorganic layers,aligning to favor charge transport along the vertical direction.In addition,introducing high electronegativity led to increased intermolecular interactions,resulting in enhanced structural stability and improved phenyl ring π-orbital overlap and interlayer electron coupling,yielding efficient charge transport.Resilience to thermal stressing of the perovskite was strongly correlated with the carbon chain length of the spacer cations.The increase in cation length and the reduction in the rigidity of the amino-terminal both aided in the dispersion of thermal stress in the inorganic framework.Additional hydrogen bonding also contributed to mitigating structural disorder.
基金supported by the National Natural Science Foundation of China(NSFC)(Nos.52202371 and 51902102)the Natural Science Foundation of Shandong Province(Nos.ZR202211230173,ZR2020QE066 and ZR2021QE200)+2 种基金the Opening Project of State Key Laboratory of Advanced Technology for Float Glass(No.2020KF08)the SDUT&Zibo City Integration Development Project(No.2021SNPT0045)the fellowship of China Postdoctoral Science Foundation(No.2020M672081).
文摘Transition metal carbonates(TMCs)hold great potential as high-performance electrodes for alkali metal-ion batteries,owing to multiple-ion storage mechanisms involving conversion process and electrocatalytic reaction.However,they still suffer from inferior electronic conductivity and volume variation during delithiation/lithiation.Heterostructure and heteroatoms doping offer immense promise in enhancing reaction kinetics and structural integrity,which unfortunately have not been achieved in TMCs.Herein,a unique TMCs heterostructure with Ni-doped MnCO_(3)as“core”and Mn-doped NiCO_(3)as“shell”,which is wrapped by graphene(NM@MN/RGO),is achieved by cations differentiation strategy.The formation process for core-shell NM@MN consists of epitaxial growth of NiCO_(3)from MnCO_(3)and synchronously mutual doping,owing to the similar crystal structures but different solubility product constant/formation energy of MnCO_(3)and NiCO_(3).In-situ electrochemical impedance spectroscopy,galvanostatic intermittent titration technique,differential capacity versus voltage plots,theoretical calculation and kinetic analysis reveal the superior electrochemical activity of the NM@MN/RGO to MnCO_(3)/RGO.The NM@MN/RGO shows excellent lithium storage properties(1013.4 mAh·g^(-1)at 0.1 A·g^(-1)and 760 mAh·g^(-1)after 1000 cycles at 2 A·g^(-1))and potassium storage properties(capacity decay rate of 0.114 mAh·g^(-1)per cycle).This work proposes an efficient cation differentiation strategy for constructing advanced TMC electrodes.
基金supported by the National Natural Science Foundation of China(No.62175129)the Taishan Scholar of Shandong Province(No.tsqn202306014)the Qilu Young Scholar of Shandong University.
文摘The investigation of thermal transport properties of materials has become increasingly important in technological applications,including thermal management and energy conversion.Recently,ultrahigh or low thermal conductivity has been reported in nitride,boride,and chalcogenide by different strategies.However,the strategy to design oxide crystals with unique thermal properties is also a challenge.In this work,a new ternary oxide crystal Ga_(2)TeO_(6) is designed and expected to show high thermal conductivity due to its lone pairs-free octahedra connected along the caxis by sharing edges.The thermal conductivities of Ga_(2)TeO_(6) crystal are determined to be 19.2 and 23.9Wm^(-1) K^(-1) along the a-and c-axis directions at 323 K,respectively,which are significantly higher than those of most reported oxide crystals.First-principles calculations and crystal structure analyses reveal that the Ga_(2)TeO_(6) crystal shows high sound velocity and weak lattice anharmonicity due to lone pairs-free octahedra and highly symmetric group arrangement.The results suggest that much attention must be paid to the polyhedron with lone pairs and its arrangement in materials design to balance the functions and thermal properties.
基金supported by the Natural Science Foundation of China Grant No.52272289 and 5240223,and JSPS(Japan Society for the Promotion of Science)of Grant No.22K19088,23H00313,24H02202,and 24H02205。
文摘NiFe-layered double hydroxides(NiFe-LDHs)are among the most promising earth-abundant electrocatalysts for the oxygen evolution reaction(OER)in alkaline media.However,their practical application is hindered by intrinsic activity limitations and poor stability,primarily due to the asymmetric adsorption of oxygen intermediates.To overcome this,the binding strength must be synergistically tuned to a moderate level to optimize catalytic performance.Here,we engineered NiFeCoCr LDH through Co doping to enhance electrical conductivity and controlled Cr leaching to introduce cationic vacancies for modulating intermediate binding strength in NiFe LDH.X-ray absorption near-edge structure and extended X-ray absorption fine structure analyses reveal that NiFe-LDH with Co doping and Cr vacancies modulates the Ni oxidation state and local coordination environment,leading to a balanced electronic structure and enhanced structural complexity around the Ni sites.Additionally,these vacancies can trap OH^(-)/H_(2)O species,which can serve as a reservoir for OH^(-) transfer,facilitating the rapid formation of OER intermediates and enhancing catalytic performance at high current densities.As a result,V_(Cr)-NiFeCo LDH achieves 1.6 A cm^(-2)current density at 1.7 V vs.RHE while maintaining stable operation for over 1000 h at 500 mA cm^(-2).Density functional theory(DFT)calculations validate the synergistic effects of Co doping and Cr-induced vacancies on intermediate binding energies and improved OER kinetics.Overall,this work presents a rational design strategy to simultaneously enhance the activity and durability of NiFe-based OER catalysts for their application in high-performance alkaline water electrolysis.
基金supported by the National Natural Science Foundation of China(Nos.21925302,92250306)the Strategic Priority Research Program of the Chinese Academy of Sciences(XDB0450202)+1 种基金the Innovation Program for Quantum Science and Technology(2021ZD0303303)the National Key Research and Development Program of China(2018YFA0208702).
文摘Phonon coherence can reflect electron‒phonon coupling information and has been proven to modulate electronic states and charge transport.The manipulation of phonon coherence through spacer cation engineering in organic‒inorganic hybrid perovskites(OIHPs)has been extensively demonstrated;however,the underlying structural origin remains elusive at the molecular level.Herein,we present molecular structure and temperature-dependent coherent phonon studies via a combination of sum frequency generation vibrational spectroscopy(SFG-VS)and transient absorption spectroscopy(TAS).The conformational order of spacer cations dictates the coherent phonon oscillations in 2D OIHPs.Our study further analyzes the static order and dynamic disorder in 2D perovskites.This work provides molecular-level insights into the role of spacer cations in tuning structural order and may provide valuable guidance for advancing emergent optoelecltronics development.
基金Supported by the National Natural Science Foundation of China(No.41776177)the Qingdao Marine Science and Technology Pilot National Laboratory Fund(Nos.2016ASKJ14,QNLM2016ORP0403)。
文摘Mussels are common anchoring organisms that adhere to the surfaces of various substrates with their byssus.The adhesion of mussel to substrates is contingent upon the presence of mussel foot proteins,of which Mytilus edulis foot protein-1(Mefp-1)has been identified as the most abundant protein.It has been found that lipids are involved in the mussel adhesion process and can facilitate Mefp-1adhesion.In this research,the adhesion behavior of Mefp-1 on various substrate surfaces under the effect of typical seawater cations with or without the presence of lipid were investigated using a quartz crystal microbalance with dissipation(QCM-D).Results indicate that the presence of cations Ca^(2+),Mg^(2+),Na^(+),and K^(+)leads to varying degrees of reduction in the adhesion performance of Mefp-1 on different substrates.The degree of this reduction,however,was much alleviated in the presence of palmitic acid,which is involved in the mussel adhesion process.Therefore,the involvement of palmitic acid is advantageous for mussel protein adhesion to the substrate surface in the marine environment.This study illustrated the significant contribution of palmitic acid to mussel adhesion,which can help to better understand biofouling mechanisms and develop biomimetic adhesive materials.
基金supported by the National Key R&D Program of China(Nos.2023YFC3404200,2023YFC34042012023YFC3404202)+1 种基金the National Natural Science Foundation of China(No.22575253)the Beijing Natural Science Foundation(No.Z220025)。
文摘The development of synthetic hybrid biological systems integrating photosynthetic organisms with organic-abiotic functional materials holds significant promise for enhancing photosynthetic processes.The artificial regulation of the state transition between photosystem I(PSI)and photosystem II(PSII)represents a strategic and promising approach for improving the efficiency of natural photosynthesis.In this study,we demonstrate that poly(benzimidazolium-phenylthiophene)(CP4)featuring a flexible cationic backbone exhibits superior ultraviolet light-harvesting capability.The polymer CP4 enhanced PSI activity in Chlorella pyrenoidosa(C.pyrenoidosa),subsequently promoting PSII activity and augmenting overall photosynthetic performance.During light-dependent reactions,CP4 significantly accelerated photosynthetic electron transfer,resulting in a 330%increase in the production of oxygen and 93%and 96%increases in the ATP and NADPH contents,respectively.In the context of dark reactions,CP4 facilitated the conversion and utilization of light energy,leading to a 6%increase in both carbohydrate and protein contents.These findings indicate that synthetic light-harvesting polymer materials exhibit considerable application potential in the field of biomass production through enhancement of natural photosynthetic efficiency.
文摘Cataract is the leading cause of reversible blindness worldwide,affecting millions,particularly the elderly.Over 65 million people suffer from significant visual impairment due to cataracts,with the burden being highest in low-and middle-income countries where access to surgery is limited.Cataract surgery,one of the most commonly performed and cost-effective procedures,has evolved significantly.Traditional extracapsular cataract extraction(ECCE)has been largely replaced by phacoemulsifi cation,which uses ultrasonic energy through a small incision,reducing recovery time and complications.More recently,femtosecond laser-assisted cataract surgery(FLACS)has emerged,off ering enhanced precision but with ongoing evaluation of its cost-eff ectiveness.Intraocular lenses(IOLs)now allow for customized visual outcomes,addressing distance,near,and intermediate vision.Despite its safety,cataract surgery can still result in complications such as corneal edema and posterior capsular opacifi cation,requiring careful surgical management and patient education.
基金supported by the National Key R&D Program of China(2023YFB2406000)the National Natural Science Foundation of China(22479057,52172201,51732005)。
文摘Sodium layered oxides stand out as one of the most promising cathodes for sodium-ion batteries due to their high energy density,elemental abundance,and scalability.However,their practical applications are restricted by interplanar gliding,cation migration,and the formation of intragranular microcracks,which collectively lead to rapid structural degradation and capacity loss.Herein,we rationally design an ultrastable O3-type Na_(0.94)Ca_(0.03)Ni_(1/3)Fe_(1/3)Mn_(1/3)O_(2) cathode,in which Ca^(2+)cations act as pillars within the NaO_(2)slabs,suppressing the irreversible phase transitions and Na/TM cation migration commonly observed in layered oxides.Multiscale in situ and ex situ techniques,combined with post-mortem analysis,reveal that the Ca-pillared pinning effect not only effectively suppresses the interplanar gliding and stress accumulation within the crystal phase but also restrains Na/TM cation migration and surface reconstruction in near-surface regions.Benefiting from the combined effects of structural stabilization,the Ca-pillared cathode exhibits a superior cycling stability,retaining 81.6%of its capacity after 1000 cycles at 2 C within the voltage range of 2.0-4.0 V,along with significantly enhanced wide-temperature(from-40 to 80℃)performance.This work highlights another critical role of Ca pillars in suppressing cation migration and surface structural degradation beyond preventing adverse interplanar gliding,offering valuable insights for designing long-life and wide-temperature layered oxide cathodes.
基金financially supported the National Key R&D Program of China (No.2022YFA1502902)the National Natural Science Foundation of China (NSFC,Nos.22475152 and U21A20286)the 111 Project of China (No.D17003)。
文摘Converting CO_(2) into methanol(CH_(3)OH),a high-value-added liquid-phase product,through efficient and highly selective photocatalysis remains a significant challenge.Herein,we present a straightforward cation exchange strategy for the in-situ growth of BiVO_(4) on an InVO_(4) substrate to generate a Z-scheme heterojunction of InVO_(4)/BiVO_(4) .This in-situ partial transformation approach endows the InVO_(4)/BiVO_(4) heterojunction with a tightly connected interface,resulting in a significant improvement in charge separation efficiency between InVO_(4) and BiVO_(4).Moreover,the construction of the heterojunction reduces the formation energy barrier of the ^(*)COOH intermediate during the photoreduction of CO_(2) and increases the desorption energy barrier of the ^(*)CO intermediate,facilitating the deep reduction of ^(*)CO.Consequently,the InVO_(4)/BiVO_(4) heterojunction is capable of photocatalytic CO_(2) reduction to CH_(3)OH with high efficiency and selectivity.Under conditions where water serves as the electron source and a light intensity of 100 m W/cm^(2),the yield of CH_(3)OH reaches 130.5 μmol g^(-1)h^(-1) with a selectivity of 92 %,outperforming photocatalysts reported under similar conditions.
基金financially supported by the National Natural Science Foundation of China (No.52372188)the 111 Project (No.D17007)2023 Introduction of studying abroad talent program。
文摘Aqueous zinc-ion batteries(AZIBs) have advantages including low economic cost and high safety.Nevertheless,the serious hydrogen evolution reactions(HER) and rampant growth of Zn dendrite hinder their further development.Herein,potassium acetate(KAc) additive with cation/anion synergy effect is added into the ZnSO_(4) electrolyte to effectively promote the oriented uniform Zn deposition and suppress side reactions.According to density functional theory calculation and experimental results,CH_(3)COO^(-)(Ac^(-))anions are capable of forming stronger hydrogen bonds with H_(2)O molecules,leading to an expanded electrochemical stability window,reduced the reactivity of H_(2)O,and hence suppressing HER.Meanwhile,Ac-anions can also preferentially adsorb onto the Zn anode,promoting dense deposition towards the(100) crystal plane.Besides,dissociated K^(+) ions serve as electrostatic shielding cations,which significantly promote uniform Zn deposition and prevent dendrite formation.Thus,the Zn||Zn symmetric cell demonstrates an impressive cycle lifespan of 3000 h at 1.0 m A/cm^(2).Furthermore,the Zn||MnO_(2) full battery exhibits superior stability with a capacity retention of 86.95 % at 2.0 A/g after 4000 cycles.Therefore,the cation/anion synergy effect in KAc additive offers a viable solution to address HER and hinder dendrite growth at the interface of Zn anodes.
基金supported by the National Natural Science Foundation of China (No.20707037,40603023)
文摘The mutual effects of metal cations （Cu2＋, Pb2＋, Zn2＋, and Cd2＋） and p-nitrophenol （NP） on their adsorption desorption behavior onto wheat ash were studied. Results suggested that Cu2＋, Pb2＋, and Zn2＋ diminished the adsorption and increased the desorption of NP remarkably, while Cd2＋ had no such effect. In contrast, NP diminished the adsorption of Cu2＋, Pb2＋, and Zn2＋ onto ash, however, this suppression effect depended on the initial concentrations of metal cations. NP had no effect on Cd〉 adsorption on ash. Fourier transform infrared （FT-IR） and X-ray absorption spectroscopic （XAS） studies suggested the following mechanisms responsible for the metal suppression effect on NP adsorption： （1） large hydrated Cu2＋, Pb2＋, and Zn〉 shells occupied the surface of ash and prevent nonspecific adsorption of NP onto ash surface; （2） Cu2＋, Pb2＋, and Zn2＋ may block the micropores of ash, resulting in decreased adsorption of NP; （3） cornplexation of Cu2＋, Pb2＋, and Zn2＋ was likely via carboxyl, hydroxylic and phenolic groups of wheat ash and these same groups may also react with NP during adsorption. As a ＂soft acid＂, Cd2＋ is less efficient in the complexation of oxygencontaining acid groups than Cu2＋, Pb2＋, and Zn2＋. Thus, Cd2＋ had no effect on the adsorption of NP on wheat ash.
基金supported by the National Key Basic Research Program of China (2011CB403204)the Natural Science Foundation of China (31000200)
文摘As a pioneer leguminous shrub species for vegetation re-establishment, Caragana microphylla is widely distributed in the semi-fixed and fixed sandy lands of the Horqin region, North China. C. microphylla planta- tions modify organic carbon （SOC）, nitrogen （N） and phosphorus dynamics, bulk density and water-holding capacity and biological activities in soils, but little is known with regard to soil exchange properties. Variation in soil ex- changeable base cations was examined under C. microphylla plantations with an age sequence of 0, 5, 10, and 22 years in the Horqin Sandy Land, and at the depth of 0-10, 10-20, and 20-30 cm, respectively. C. microphylla has been planted on the non-vegetated sand dunes with similar physical-chemical soil properties. The results showed that exchangeable calcium （Ca）, magnesium （Mg）, and potassium （K）, and cation exchange capacity （CEC） were significantly increased, and Ca saturation tended to decrease, while Mg and K saturations were increased with the plantation years. No difference was observed for exchangeable sodium （Na） neither with plantation years nor at soil depths. Of all the base cations and soil layers, exchangeable K at the depth of 0-10 cm accumulated most quickly, and it increased by 1.76, 3.16, and 4.25 times, respectively after C. microphylla was planted for 5, 10, and 22 years. Exchangeable Ca, Mg, and K, and CEC were significantly （P〈0.001） and positively correlated with SOC, total N, pH and electrical conductivity （EC）. Soil pH and SOC are regarded as the main factors influencing the variation in ex- changeable cations, and the preferential absorption of cations by plants and different leaching rates of base cations that modify cation saturations under C. microphylla plantation. It is concluded that as a nitrogen-fixation species, C. microphylla plantation is beneficial to increasing exchangeable base cations and CEC in soils, and therefore can improve soil fertility and create favorable microenvironments for plants and creatures in the semi-arid sandy land ecosystems.
基金This project was financially supported by the National Natural Science Foundation of China (No. 50274010)the National High-Tech Research and Development Program of China ("863" Program, No. 2002AA-302404).
文摘The effects of alkaline cations （M^＋ = Li^＋, Na^＋, K^＋, Cs^＋）on the electrochemical synthesis of polyaniline were carfled out under cyclovoltammetric conditions using nitrates of Li^＋, Na^＋, K^＋, and Cs^＋ as the supporting electrolytes. The results show that the oxidation potentials of aniline in the electrolytes decrease as the protonation extent of aniline decreases from the fast scan, which is caused by the decrease of the ionic radius of alkaline metal ions at the same concentration of alkaline cations. With the scan number increasing, the deposit charge Q as the characteristic growth function also depends on the protonation of aniline, and it increases with the ionic radius of alkaline cations increasing. SEM images show the effect of alkaline cations on the morphology of polyaniline. It is clear that the ionic mobility of alkaline cations is further lower than that of W. Alkaline cations and counter-ions were the species responsible for the enhancement of Pani electrosynthesis. Therefore, this is exactly what SEM images show： a relatively rough fibrous structure in the case of Pani-H^＋ suggesting a sponge-like structure and a highly orderly fiber-like structure in the case of Pani-M^＋.
基金Project supported by the National Natural Science Foundation of China(No.30670392)the Knowledge Innovation Program of the Chinese Academy of Sciences(Nos.KZCX2-YW-432 and KSCX2-SW-133)
文摘The effects of simulated nitrogen(N)deposition on soil exchangeable cations were studied in three forest types of subtropical China.Four N treatments with three replications were designed for the monsoon evergreen broadleaf forest (mature forest):control(0 kg N ha-1 year-1),low N(50 kg N ha-1 year-1),medium N(100 kg N ha-1 year-1)and high N(150 kg N ha-1 year-1),and only three treatments(i.e.,control,low N,medium N)were established for the pine and mixed forests.Nitrogen had been applied continuously for 26 months before the measurement.The mature forest responded more rapidly and intensively to N additions than the pine and mixed forests,and exhibited some significant negative symptoms,e.g.,soil acidification,Al mobilization and leaching of base cations from soil.The pine and mixed forests responded slowly to N additions and exhibited no significant response of soil cations.Response of soil exchangeable cations to N deposition varied in the forests of subtropical China,depending on soil N status and land-use history.
