We report on the synthesis and the characterisation of metal/semiconductor hybrids consisting of self-assembled CdS nanoparticles on Cd nanowires, which are grown by thermal evaporation of the mixture of CdS and Cr. T...We report on the synthesis and the characterisation of metal/semiconductor hybrids consisting of self-assembled CdS nanoparticles on Cd nanowires, which are grown by thermal evaporation of the mixture of CdS and Cr. The growth of the hybrids is attributed to the decomposition of CdS at high temperature and the strain relieving that arises mainly from the lattice mismatch between Cd and CdS. Temperature dependence of zerc^field resistance of single nanohybrid indicates that the as-produced Cd/CdS nanohybrid undergoes a metal-semiconductor transition as a natural consequence of hybrid from metallic Cd and semiconducting CdS. The metal/semiconductor hybrid property provides a promising basis for the development of novel nanoelectronic devices.展开更多
A full-coupling model on the current-voltage(J-V)characteristics of PN junctions is put forward in the paper by taking into account both the whole junction and the two electrode regions consisting of metal/semiconduct...A full-coupling model on the current-voltage(J-V)characteristics of PN junctions is put forward in the paper by taking into account both the whole junction and the two electrode regions consisting of metal/semiconductor(M/S)contacts.The depletion layer assumption proposed by the Shockley model is discarded.Gauss’law on the electric potential and the electric field is applied in the whole junction region such that the majority-carrier currents inside and outside the P/N barrier region are able to be exactly defined and clearly calculated.Then,the stable continuity equations of the electron and hole currents are established to show the current conversion between minority-and majority-carriers inside the whole PN junction region.By analyzing all the conversion procedure,the J-V characteristics of a PN junction are obtained with good agreement to the experimental results,which are closely dependent on the minority-carrier lifetime and doping concentrations.Obviously,the study on this topic possesses referential significance to mechanically tuning the performance of piezoelectric PN junctions and piezotronic devices.展开更多
Direct alcohol fuel cells(DAFCs)have received wide attention as a new type of clean energy device because of their high energy conversion efficiency,portability,non-toxicity and pollution-free.Anode catalysts are the ...Direct alcohol fuel cells(DAFCs)have received wide attention as a new type of clean energy device because of their high energy conversion efficiency,portability,non-toxicity and pollution-free.Anode catalysts are the key factors affecting the performance of DAFCs.Recently studies show that using the optical activity of semiconductor materials as the carriers of traditional precious metal electrocatalysts,under the illumination of light sources,can greatly improve the electrocatalytic activity and stability of electrodes.In this review,the research progress of photo-responsive metal/semiconductor hybrids as the electrocatalysts for DAFCs in recent years is summarized,including:(1)Mechanism and advantages of photo-assistant electrochemical alcohol oxidation reaction,(2)me tal/semiconductor electrocatalyst for the different type of fuel cell reactions,(3)different kind of metals in photo-responsive metal/semiconductor hybrid nanostructure,(4)the personal prospects of the photo-responsive metal/semiconductor electrode for future application in DAFCs.展开更多
The effect of intermetallic particles on the corrosion of 6061 aluminum alloy and its coating used in semiconductor processing systems was systematically studied via liquid and gas experiments and micromorphology char...The effect of intermetallic particles on the corrosion of 6061 aluminum alloy and its coating used in semiconductor processing systems was systematically studied via liquid and gas experiments and micromorphology characterization.The results revealed that a huge difference of corrosion resistance between imported and domestic 6061 aluminum alloys in HCl solution and gas acid mist experiments mainly was attributed to the different size and amount of Al_(15)(Fe,Mn)_(3)Si_(2).The corrosion resistance of domestic 6061 alloy in dry/wet semiconductor electronic special gas environments was worse than that of imported aluminum alloy,and there are great differences in the corrosion mechanism of 6061 alloy caused by the second phase in the two dry/wet environments.And the corrosion resistance of the hard anodized alumina film was closely related to the microscopic morphology of holes.The vertical and elongatedα-Al_(15)(Mn,Fe)_(3)Si_(2) phase was formed in the rolled aluminum alloy that has been rolled perpendicular to the surface of the substrate.Compared to the horizontal long hole,the longitudinal long holes generated by the verticalα-Al_(15)(Mn,Fe)_(3)Si_(2) phase will enable the corrosive medium to reach the substrate rapidly,which significantly weakens the corrosion resistance of the hard anodized film.展开更多
Intrinsically stretchable semiconducting polymers play a vital role in the development of wearable electronics,featuring low-cost,large-area and high-density fabrication.Only single-stage dynamic chemical bond has bee...Intrinsically stretchable semiconducting polymers play a vital role in the development of wearable electronics,featuring low-cost,large-area and high-density fabrication.Only single-stage dynamic chemical bond has been widely incorporated into polymer backbones to afford stretchability while multiple dynamic bonds have not been investigated,making a formidable challenge to achieve high stretchability without compromising charge transport properties.Herein,we synthesize a series of stretchable polymer semiconductors incorporating urethane and bipyridine units,which can provide dynamic interconnected polymer network by combination of hydrogen bonds with metal coordination,simultaneously obtaining excellent stretchability and carrier mobilities.Compared with single-stage hydrogen bonds,multiple dynamic chemical bonds constructed by 10% hydrogen bonds and 0.25 equiv.metal coordination endowed the polymer semiconductors with an 58% enhancement in carrier mobility and a two-fold increase in crack-onset strain.Notably,the polymer exhibited stable carrier mobilities parallel to the stretching direction,with 91% of initial values even under 150% strain,which is the unprecedented value for intrinsically stretchable semiconducting polymers without blending of elastomers.Therefore,the introduction of multiple dynamic bonds provides an effective and promising approach for intrinsically stretchable and high-performance polymer semiconductor.展开更多
Under hydrothermal and solvothermal conditions,two novel cobalt-based complexes,{[Co_(2)(CIA)(OH)(1,4-dtb)]·3.2H_(2)O}n(HU23)and{[Co_(2)(CIA)(OH)(1,4-dib)]·3.5H2O·DMF}n(HU24),were successfully construct...Under hydrothermal and solvothermal conditions,two novel cobalt-based complexes,{[Co_(2)(CIA)(OH)(1,4-dtb)]·3.2H_(2)O}n(HU23)and{[Co_(2)(CIA)(OH)(1,4-dib)]·3.5H2O·DMF}n(HU24),were successfully constructed by coordinatively assembling the semi-rigid multidentate ligand 5-(1-carboxyethoxy)isophthalic acid(H₃CIA)with the Nheterocyclic ligands 1,4-di(4H-1,2,4-triazol-4-yl)benzene(1,4-dtb)and 1,4-di(1H-imidazol-1-yl)benzene(1,4-dib),respectively,around Co^(2+)ions.Single-crystal X-ray diffraction analysis revealed that in both complexes HU23 and HU24,the CIA^(3-)anions adopt aκ^(7)-coordination mode,bridging six Co^(2+)ions via their five carboxylate oxygen atoms and one ether oxygen atom.This linkage forms tetranuclear[Co4(μ3-OH)2]^(6+)units.These Co-oxo cluster units were interconnected by CIA^(3-)anions to assemble into 2D kgd-type structures featuring a 3,6-connected topology.The 2D layers were further connected by 1,4-dtb and 1,4-dib,resulting in 3D pillar-layered frameworks for HU23 and HU24.Notably,despite the similar configurations of 1,4-dtb and 1,4-dib,differences in their coordination spatial orientations lead to topological divergence in the 3D frameworks of HU23 and HU24.Topological analysis indicates that the frameworks of HU23 and HU24 can be simplified into a 3,10-connected net(point symbol:(4^(10).6^(3).8^(2))(4^(3))_(2))and a 3,8-connected tfz-d net(point symbol:(4^(3))_(2)((4^(6).6^(18).8^(4)))),respectively.This structural differentiation confirms the precise regulatory role of ligands on the topology of metal-organic frameworks.Moreover,the ultraviolet-visible absorption spectra confirmed that HU23 and HU24 have strong absorption capabilities for ultraviolet and visible light.According to the Kubelka-Munk method,their bandwidths were 2.15 and 2.08 eV,respectively,which are consistent with those of typical semiconductor materials.Variable-temperature magnetic susceptibility measurements(2-300 K)revealed significant antiferromagnetic coupling in both complexes,with their effective magnetic moments decreasing markedly as the temperature lowered.CCDC:2457554,HU23;2457553,HU24.展开更多
As the chemical industry expands,the use of benzene,toluene,and xylene(collectively known as BTX)in industrial production has increased greatly.Meanwhile,the toxic nature and potential health hazards of BTX gases cann...As the chemical industry expands,the use of benzene,toluene,and xylene(collectively known as BTX)in industrial production has increased greatly.Meanwhile,the toxic nature and potential health hazards of BTX gases cannot be ignored due to low-concentration leaks underline the critical need for rapid and real-time monitoring of these gases.Chemiresistive metal oxide semiconductor(MOS)-based gas sensors,which are extensively used for gas detection in both industrial settings and everyday life,emerge as one of the optimal solutions for trace BTX detection.These sensors are highly valued for their high sensitivity and low detection limits.Nevertheless,the improvement of selectivity towards specific BTX gases to achieve efficient and precise detection still remains challenging.This review summarizes the chemiresistive MOS-based gas sensors designed for BTX detection,categorizing them based on the components of sensing materials-basically into three groups:single-component,single heterojunction,and multiple heterojunctions gas sensing materials.Further,the review proposes the future application prospects of chemiresistive MOS-based BTX gas sensors,with specific emphasis on their significance in promoting industrial safety and environmental monitoring.展开更多
39 soil samples surrounding a lead-zinc mining area in Guangxi were collected,and the contents of Pb,Hg,Cd,Cr,As,Cu,Zn,and Ni were determined to investigate the pollution characteristics and sources of heavy metals.Ar...39 soil samples surrounding a lead-zinc mining area in Guangxi were collected,and the contents of Pb,Hg,Cd,Cr,As,Cu,Zn,and Ni were determined to investigate the pollution characteristics and sources of heavy metals.ArcGIS inverse distance weight difference method was used to analyze the characteristics of pollution distribution,and single-factor pollution index,Nemerow comprehensive pollution index,ground accumulation index,and potential ecological risk index were selected to evaluate the characteristics of heavy metal pollution.Based on correlation analysis,the absolute principal component-multiple linear regression(APCS-MLR)and positive definite matrix factorization(PMF)models were used to analyze the sources of soil heavy metals.The results showed that the average concentrations of all eight heavy metals exceeded both national and Guangxi soil background values.Hg,Cd,and Zn exhibited high variation(greater than 0.5),indicating significant external disturbances,and their spatial distribution was closely related to mining activity locations.The single-factor pollution index evaluation indicated varying degrees of pollution risk for Cd,Zn,and As,with Cd and Zn being the most severe pollutants,as 69.23%and 30.77%of the samples fell into the moderate pollution or higher category.The geoaccumulation index analysis ranked the mean pollution levels of the eight elements as follows:Zn>Cd>Ni>Pb>Cu>Cr>Hg>As,with Cd and Zn showing the most severe contamination,and 51.28%of the samples exhibiting moderate or higher pollution levels.The Nemerow comprehensive pollution index evaluation showed that 74.35%of soil samples were classified as moderate to heavy pollution.The potential ecological risk index assessment indicated significant ecological risks posed by Cd and Zn,with 82.05%and 5.12%of the samples classified as causing strong to extreme ecological risks,respectively.The source apportionment analysis revealed minor differences between the two models.The APCS-MLR model identified three pollution sources and their contribution rates:anthropogenic mining sources(31.13%),parent material sources(40.38%),and unidentified sources(28.49%).The PMF model identified three pollution sources with contribution rates of anthropogenic mining sources(26.10%),parent material sources(46.96%),and a combined traffic and agricultural source(26.61%).Pb,Hg,Cd,and Zn mainly originated from mining activities;Cr,As,and Ni were primarily derived from the parent material,while Cu was predominantly attributed to traffic and agricultural sources.These findings provide a scientific basis for the prevention and control of heavy metal pollution in mining areas.展开更多
Refractory metals,including tungsten(W),tantalum(Ta),molybdenum(Mo),and niobium(Nb),play a vital role in industries,such as nuclear energy and aerospace,owing to their exceptional melting temperatures,thermal durabili...Refractory metals,including tungsten(W),tantalum(Ta),molybdenum(Mo),and niobium(Nb),play a vital role in industries,such as nuclear energy and aerospace,owing to their exceptional melting temperatures,thermal durability,and corrosion resistance.These metals have body-centered cubic crystal structure,characterized by limited slip systems and impeded dislocation motion,resulting in significant low-temperature brittleness,which poses challenges for the conventional processing.Additive manufacturing technique provides an innovative approach,enabling the production of intricate parts without molds,which significantly improves the efficiency of material usage.This review provides a comprehensive overview of the advancements in additive manufacturing techniques for the production of refractory metals,such as W,Ta,Mo,and Nb,particularly the laser powder bed fusion.In this review,the influence mechanisms of key process parameters(laser power,scan strategy,and powder characteristics)on the evolution of material microstructure,the formation of metallurgical defects,and mechanical properties were discussed.Generally,optimizing powder characteristics,such as sphericity,implementing substrate preheating,and formulating alloying strategies can significantly improve the densification and crack resistance of manufactured parts.Meanwhile,strictly controlling the oxygen impurity content and optimizing the energy density input are also the key factors to achieve the simultaneous improvement in strength and ductility of refractory metals.Although additive manufacturing technique provides an innovative solution for processing refractory metals,critical issues,such as residual stress control,microstructure and performance anisotropy,and process stability,still need to be addressed.This review not only provides a theoretical basis for the additive manufacturing of high-performance refractory metals,but also proposes forward-looking directions for their industrial application.展开更多
Metals,indispensable since the Bronze Age,remain pivotal in modern technologies due to their exceptional properties and versatility.Beyond traditional machining,advanced nano/micro-machining techniques enable the fabr...Metals,indispensable since the Bronze Age,remain pivotal in modern technologies due to their exceptional properties and versatility.Beyond traditional machining,advanced nano/micro-machining techniques enable the fabrication of metallic nano/micro structures with high precision in shape,size,and pattern.These structures endow flexible electrodes with outstanding electrical,mechanical,optical,and electrochemical performance,enabling growing applications in flexible optoelectronics,epidermal electronics,energy harvesting,and biochemical sensing.This review provides a comprehensive overview of the fabrication strategies for flexible electrodes made from metal meshes,metal nanowires,and liquid metals.The current advancements,existing challenges,and emerging technologies are systematically discussed.Furthermore,the progression toward ultra-thin,soft epidermal electrodes is explored,with an emphasis on novel in situ and transfer fabrication methods.We examine the underlying mechanisms,performance indicators,and their integration for on-skin applications,including bioelectric sensing,electrical stimulation,and energy harvesting.Finally,we highlight the remaining challenges in performance improvement and industrialization of flexible and epidermal electrodes,along with future opportunities for integrating multimodal systems and leveraging artificial intelligence to enhance their functionalities.展开更多
Platinum group metals have high melting points,strong corrosion resistance,stable chemical properties,and low oxygen permeability in high-temperature oxygen-containing environments.As thermal protective coating materi...Platinum group metals have high melting points,strong corrosion resistance,stable chemical properties,and low oxygen permeability in high-temperature oxygen-containing environments.As thermal protective coating materials,they have gained essential applications in the aerospace field and have excellent prospects for application in frontier military fields,such as protecting hot-end components of hypersonic aircraft.This research reviewed the latest research progress of platinum group metal coatings with hightemperature oxidation resistance,including coating preparation techniques,oxidation failure,and alloying modification.The leading preparation techniques of current platinum group metal coatings were discussed,as well as the advantages and disadvantages of various existing preparation techniques.Besides,the intrinsic properties,failure forms,and failure mechanisms of coatings of single platinum group metal in high-temperature oxygen-containing environments were analyzed.On this basis,the necessity,main methods,and main achievements of alloying modification of platinum group metals were summarized.Finally,the future development of platinum group coatings with high-temperature oxidation resistance was discussed and prospected.展开更多
Composite solid-state electrolytes incorporating metal-organic frameworks(MOFs)demonstrate tremendous potential for ameliorating Li^(+)conduction in lithium metal batteries.However,their practical application is hinde...Composite solid-state electrolytes incorporating metal-organic frameworks(MOFs)demonstrate tremendous potential for ameliorating Li^(+)conduction in lithium metal batteries.However,their practical application is hindered by low ionic co nductivity and unstable Li^(+)transport at the electrode interfaces.To overcome these challenges,a previously unreported family of indium based MOFs(In-BDC-F_(x),x=0,4,6)with tunable fluorine content was synthesized and integrated into PVDF-HFP matrices to construct highperformance quasi-solid-state electrolytes.By systematically modulating linker fluorination,a bifunctional enhancement mechanism is revealed:fluorinated indium centers simultaneously suppress polymer crystallinity and establish preferential Li^(+)conduction pathways.Remarkably,In-BDC-F_(6) manifests exceptional synergistic interactions between-CF_(3) functionalities and indium coordination sites,amplifying Lewis acidity to facilitate LiTFSI dissociation and TFSI-immobilization,culminating in homogeneous LiF-enriched solid electrolyte interphases.The optimized electrolyte demonstrates compelling electrochemical performance:ionic conductivity of 9.68×10^(-4) S cm^(-1),Li^(+)transference number of 0.70,and electrochemical stability window of 4.96 V.Li‖Li symmetric cell demonstrated a critical current density of 3.5 mA cm^(-2) and stable plating/stripping for over 1000 h at 0.2 mA cm^(-2),while LiFePO_(4)‖Li cells retain96.66%capacity after 1300 cycles at 10C,underscoring the transformative potential of fluorinated MOF architectures in fast-charging solid-state batteries.展开更多
Violet phosphorus,a recently explored layered elemental semiconductor,has attracted much attention due to its unique photoelectric,mechanical properties,and high hole mobility.Herein,violet arsenic phosphorus has for ...Violet phosphorus,a recently explored layered elemental semiconductor,has attracted much attention due to its unique photoelectric,mechanical properties,and high hole mobility.Herein,violet arsenic phosphorus has for the first time been synthesized by a molten lead method.The crystal structure of violet arsenic phosphorus(P^(83.4)As_(0.6),CSD-2408761)was determined by single crystal X-ray diffraction to have similar structure as that of violet phosphorus,where P12 is occupied by arsenic/phosphorus(As/P)atoms as mixed occupancy sites As1/P12.The arsenic substitution has been demonstrated to tune the band structure of violet phosphorus,switching p-type of violet phosphorus to high-performance n-type violet arsenic phosphorus.The effective electron mass along the<010>direction is significantly reduced from 1.792 to 0.515 m_(0)by arsenic substitution,resulting in an extremely high electron mobility of 2622.503 cm^(2)V^(-1)s^(-1).The field effect transistor built with P_(83.4)As_(0.6)nanosheets was measured to have a high electron mobility(137.06 cm^(2)V^(-1)s^(-1),61.2 nm),even under ambient conditions for 5 h,much higher than the hole mobility of violet phosphorene nanosheets(4.07 cm^(2)V^(-1)s^(-1),73.3 nm).This work provides a new idea for designing phosphorus-based materials for field effect transistors,giving significant potential in complementary metal-oxide-semiconductor applications.展开更多
Aqueous zinc ion batteries(AZIBs)are considered promising candidates owing to their inherent safety and low cost.However,the conventional glass fiber(GF)separator used in AZIBs suffers from poor physicochemical proper...Aqueous zinc ion batteries(AZIBs)are considered promising candidates owing to their inherent safety and low cost.However,the conventional glass fiber(GF)separator used in AZIBs suffers from poor physicochemical properties,leading to uncontrolled zinc(Zn)dendrite formation and undesirable side reactions.To address these limitations and enhance the electrochemical performance of AZIBs,a precisely designed functional separator is developed by incorporating UiO-66-(COOH)_(2)into a poly(vinylidene fluoride)(PVDF)framework(U-PVDF)via a direct in situ growth method.This approach enables uniform distribution of UiO-66-(COOH)_(2)both on the surface and within the PVDF backbone,without increasing separator thickness.Owing to the strong interaction between Zn^(2+)and the abundant carboxyl groups in UiO-66-(COOH)_(2),the U-PVDF separator regulates the Zn^(2+)solvation structure toward a contact ion pair-dominated structure by reducing coordinated water molecules,which effectively mitigates water-induced parasitic reactions and promotes compact Zn deposition.Consequently,a Zn/Zn symmetric cell employing the U-PVDF separator demonstrates superior cycling stability over 1500 cycles without internal short-circuiting at a current density of 6 mA cm^(−2)and an areal capacity of 2 mAh cm^(−2).Moreover,Zn/NaV_(3)O_(8)·xH_(2)O(NVO)cell with the U-PVDF separator exhibits markedly improved cyclability and rate performance compared with those using conventional GF separator.展开更多
Piezoelectric semiconductor(PSC)materials exhibit strong electromechanical coupling affected by free carriers,which makes their contact behavior essential for sensors,actuators,and electronic devices.Analytical models...Piezoelectric semiconductor(PSC)materials exhibit strong electromechanical coupling affected by free carriers,which makes their contact behavior essential for sensors,actuators,and electronic devices.Analytical models for three-dimensional(3D)PSC contact problems are still scarce,especially for conductive indenters.This work develops a semi-analytical framework to study the 3D frictionless contact between a conductive indenter and a PSC half-space.Fundamental solutions under a unit force and a unit electric charge are derived,and the corresponding frequency response functions are combined with a discrete convolution-fast Fourier transform(DC-FFT)algorithm to achieve an efficient semi-analytical contact model.The numerical results demonstrate that an increase in the surface charge density reduces the indentation pressure and modifies the electric potential distribution.A higher steady carrier concentration enhances the screening effect,suppresses the electromechanical coupling,and shifts the system response toward purely elastic behaviors.The sensitivity analysis shows that the indentation depth is dominated by the elastic constants,while the electric potential is mainly affected by the piezoelectric coefficient.Although the analysis is carried out with spherical indenters,the model is not limited to a specific indenter shape.It provides an effective tool for investigating complex 3D PSC contact problems and offers useful insights into the design of PSC materials-based devices.展开更多
We present a systematic investigation of the superconductivity in high-quality CsTi_(3)Bi_(5) single crystals by combining bulk property characterization and local-probe spectroscopy.Two successive superconducting tra...We present a systematic investigation of the superconductivity in high-quality CsTi_(3)Bi_(5) single crystals by combining bulk property characterization and local-probe spectroscopy.Two successive superconducting transitions are observed in this newly discovered kagome material.In the first stage,the diamagnetic response strengthens significantly from T_(c)~4.9 K to 4.6 K,followed by a broad transition below 4.6 K in the second stage.Moreover,different magnetic field dependences are observed for the two stages,where the first stage is field-insensitive while the second stage exhibits strong field dependence.The ultra-low magnetic field measurements indicate that the lower critical field H_(c1)(T)exhibits small anisotropy.Based on a comparative study of the superconducting state in CsBi2 and microscopic verification via scanning tunneling microscopy(STM),our results suggest the emergence of exotic and intrinsic superconductivity in this new titanium-based kagome superconductor,establishing it as a promising platform for further exploring the complexity of electronic states in the kagome lattice.展开更多
[Objectives]To analyze the current status of heavy metal contamination in soils of vegetable cultivation bases located in Huichuan District,Zunyi City.[Methods]Soil samples from various depths within the vegetable cul...[Objectives]To analyze the current status of heavy metal contamination in soils of vegetable cultivation bases located in Huichuan District,Zunyi City.[Methods]Soil samples from various depths within the vegetable cultivation bases of Guanba Village,Sidu Village,and Banqiao Village in Huichuan District,Zunyi City,were selected as the subjects of this study.The concentrations of five heavy metals,including lead(Pb),mercury(Hg),cadmium(Cd),arsenic(As),and chromium(Cr),were measured at different soil depths.The Nemerow comprehensive pollution index method was employed to assess heavy metal contamination,and the analysis was conducted in accordance with the farmland environmental quality evaluation standards for edible agricultural products.[Results]The concentrations of Cd and As at the sample collection sites were relatively elevated.The pollution level of Cd reached grade III or above,indicating moderate contamination in certain topsoil areas.Most As concentrations corresponded to grade II and grade III pollution levels.In contrast,Hg,Pb,and Cr concentrations remained within the safety standards established for agricultural products.However,Cd and As levels predominantly surpassed these safety thresholds.Notably,Guanba Village and Sidu Village exhibited significant pollution levels,warranting comprehensive investigations into the sources of contamination.[Conclusions]This study offers valuable insights for advancing the sustainable development of local agriculture and for the prevention and management of soil contamination.展开更多
Peptides play important roles in chemistry,medicinal chemistry and life science,due to their high efficiency and specificity,unusual biological and therapeutic properties.As naturally occurring peptides often face wit...Peptides play important roles in chemistry,medicinal chemistry and life science,due to their high efficiency and specificity,unusual biological and therapeutic properties.As naturally occurring peptides often face with their intrinsic limitations including metabolic instability and low membrane permeability,the strategies for synthesizing unnatural amino acids and peptides are explored.Among the methods for modifying amino acids and peptides,chemo-and site-selective approaches are preferred because of the ability to fine-tuning structural features.Recently,transition metal-catalyzed Csingle bondH activation has been employed for the functionalization of amino acids and peptides.Through domino Csingle bondH activation/annulation,a series of structurally complex and diverse amino acids and peptides is constructed.This review highlights recent advances in the synthesis of unnatural amino acids and peptides via transition metal-catalyzed Csingle bondH activation/annulation.展开更多
Due to the intrinsic interaction between piezoelectric effects and semiconducting properties,piezoelectric semiconductors(PSs)have great promise for applications in multi-functional electronic devices,requiring a deep...Due to the intrinsic interaction between piezoelectric effects and semiconducting properties,piezoelectric semiconductors(PSs)have great promise for applications in multi-functional electronic devices,requiring a deep understanding of the multi-field coupling behavior.This work investigates the free vibration and buckling characteristics of a PS beam under different mechanical boundary conditions.The coupling fields of a PS beam are modeled by combining the Timoshenko beam theory for mechanical fields with a high-order expansion along the beam thickness for electric fields and carrier distributions.Based on the hypothesis of small perturbation of carrier density,the governing equations and boundary conditions are derived with the principle of virtual work.The differential quadrature method(DQM)is used to solve the boundary-value problem.The analytical solutions for a simply supported-simply supported(SS)PS beam are also obtained for verification.The convergence and correctness of the solutions obtained with the DQM are first evaluated.Subsequently,the effects of initial electron density,boundary conditions,and geometric parameters on the vibration and buckling characteristics are explored through numerical examples,where the finite element simulations are also included.The interaction mechanism of multi-physics fields is revealed.The scale effect on the static and dynamic responses of a PS beam is demonstrated.The derived model and findings are useful for the analysis and design of PS-based devices.展开更多
基金Project supported by the National Natural Science Foundation of China (Grant No 60806005)
文摘We report on the synthesis and the characterisation of metal/semiconductor hybrids consisting of self-assembled CdS nanoparticles on Cd nanowires, which are grown by thermal evaporation of the mixture of CdS and Cr. The growth of the hybrids is attributed to the decomposition of CdS at high temperature and the strain relieving that arises mainly from the lattice mismatch between Cd and CdS. Temperature dependence of zerc^field resistance of single nanohybrid indicates that the as-produced Cd/CdS nanohybrid undergoes a metal-semiconductor transition as a natural consequence of hybrid from metallic Cd and semiconducting CdS. The metal/semiconductor hybrid property provides a promising basis for the development of novel nanoelectronic devices.
基金Project supported by the National Natural Science Foundation of China (Nos.11972164,11672113,11472182)the Key Laboratory Project of Hubei Province of China (No.2016CFA073)。
文摘A full-coupling model on the current-voltage(J-V)characteristics of PN junctions is put forward in the paper by taking into account both the whole junction and the two electrode regions consisting of metal/semiconductor(M/S)contacts.The depletion layer assumption proposed by the Shockley model is discarded.Gauss’law on the electric potential and the electric field is applied in the whole junction region such that the majority-carrier currents inside and outside the P/N barrier region are able to be exactly defined and clearly calculated.Then,the stable continuity equations of the electron and hole currents are established to show the current conversion between minority-and majority-carriers inside the whole PN junction region.By analyzing all the conversion procedure,the J-V characteristics of a PN junction are obtained with good agreement to the experimental results,which are closely dependent on the minority-carrier lifetime and doping concentrations.Obviously,the study on this topic possesses referential significance to mechanically tuning the performance of piezoelectric PN junctions and piezotronic devices.
基金the National Natural Science Foundation of China(Nos.21603111,51702173)Guangdong Basic and Applied Basic Research Foundation(No.2020B1515020038)the Pearl River Talent Recruitment Program of Guangdong Province(No.2019QN01L148)。
文摘Direct alcohol fuel cells(DAFCs)have received wide attention as a new type of clean energy device because of their high energy conversion efficiency,portability,non-toxicity and pollution-free.Anode catalysts are the key factors affecting the performance of DAFCs.Recently studies show that using the optical activity of semiconductor materials as the carriers of traditional precious metal electrocatalysts,under the illumination of light sources,can greatly improve the electrocatalytic activity and stability of electrodes.In this review,the research progress of photo-responsive metal/semiconductor hybrids as the electrocatalysts for DAFCs in recent years is summarized,including:(1)Mechanism and advantages of photo-assistant electrochemical alcohol oxidation reaction,(2)me tal/semiconductor electrocatalyst for the different type of fuel cell reactions,(3)different kind of metals in photo-responsive metal/semiconductor hybrid nanostructure,(4)the personal prospects of the photo-responsive metal/semiconductor electrode for future application in DAFCs.
基金financially supported by the Program of the National Natural Science Foundation of China(Grant No.52371055)the Young Elite Scientist Sponsorship Program Cast(Grant No.YESS20200139)the Basic Scientific Research Project of Liaoning Provincial Department of Education(Grant No.JYTMS20230618)。
文摘The effect of intermetallic particles on the corrosion of 6061 aluminum alloy and its coating used in semiconductor processing systems was systematically studied via liquid and gas experiments and micromorphology characterization.The results revealed that a huge difference of corrosion resistance between imported and domestic 6061 aluminum alloys in HCl solution and gas acid mist experiments mainly was attributed to the different size and amount of Al_(15)(Fe,Mn)_(3)Si_(2).The corrosion resistance of domestic 6061 alloy in dry/wet semiconductor electronic special gas environments was worse than that of imported aluminum alloy,and there are great differences in the corrosion mechanism of 6061 alloy caused by the second phase in the two dry/wet environments.And the corrosion resistance of the hard anodized alumina film was closely related to the microscopic morphology of holes.The vertical and elongatedα-Al_(15)(Mn,Fe)_(3)Si_(2) phase was formed in the rolled aluminum alloy that has been rolled perpendicular to the surface of the substrate.Compared to the horizontal long hole,the longitudinal long holes generated by the verticalα-Al_(15)(Mn,Fe)_(3)Si_(2) phase will enable the corrosive medium to reach the substrate rapidly,which significantly weakens the corrosion resistance of the hard anodized film.
基金the Fundamental Research Funds for the Central Universities(No.buctrc202103)the National Natural Science Foundation of China(Nos.52373170,22171019)+1 种基金Beijing Natural Science Foundation(No.2252015),SINOPEC(No.225057)Open Project Program of the State Key Laboratory of Fine Chemicals(No.KF2201,Dalian University of Technology)。
文摘Intrinsically stretchable semiconducting polymers play a vital role in the development of wearable electronics,featuring low-cost,large-area and high-density fabrication.Only single-stage dynamic chemical bond has been widely incorporated into polymer backbones to afford stretchability while multiple dynamic bonds have not been investigated,making a formidable challenge to achieve high stretchability without compromising charge transport properties.Herein,we synthesize a series of stretchable polymer semiconductors incorporating urethane and bipyridine units,which can provide dynamic interconnected polymer network by combination of hydrogen bonds with metal coordination,simultaneously obtaining excellent stretchability and carrier mobilities.Compared with single-stage hydrogen bonds,multiple dynamic chemical bonds constructed by 10% hydrogen bonds and 0.25 equiv.metal coordination endowed the polymer semiconductors with an 58% enhancement in carrier mobility and a two-fold increase in crack-onset strain.Notably,the polymer exhibited stable carrier mobilities parallel to the stretching direction,with 91% of initial values even under 150% strain,which is the unprecedented value for intrinsically stretchable semiconducting polymers without blending of elastomers.Therefore,the introduction of multiple dynamic bonds provides an effective and promising approach for intrinsically stretchable and high-performance polymer semiconductor.
文摘Under hydrothermal and solvothermal conditions,two novel cobalt-based complexes,{[Co_(2)(CIA)(OH)(1,4-dtb)]·3.2H_(2)O}n(HU23)and{[Co_(2)(CIA)(OH)(1,4-dib)]·3.5H2O·DMF}n(HU24),were successfully constructed by coordinatively assembling the semi-rigid multidentate ligand 5-(1-carboxyethoxy)isophthalic acid(H₃CIA)with the Nheterocyclic ligands 1,4-di(4H-1,2,4-triazol-4-yl)benzene(1,4-dtb)and 1,4-di(1H-imidazol-1-yl)benzene(1,4-dib),respectively,around Co^(2+)ions.Single-crystal X-ray diffraction analysis revealed that in both complexes HU23 and HU24,the CIA^(3-)anions adopt aκ^(7)-coordination mode,bridging six Co^(2+)ions via their five carboxylate oxygen atoms and one ether oxygen atom.This linkage forms tetranuclear[Co4(μ3-OH)2]^(6+)units.These Co-oxo cluster units were interconnected by CIA^(3-)anions to assemble into 2D kgd-type structures featuring a 3,6-connected topology.The 2D layers were further connected by 1,4-dtb and 1,4-dib,resulting in 3D pillar-layered frameworks for HU23 and HU24.Notably,despite the similar configurations of 1,4-dtb and 1,4-dib,differences in their coordination spatial orientations lead to topological divergence in the 3D frameworks of HU23 and HU24.Topological analysis indicates that the frameworks of HU23 and HU24 can be simplified into a 3,10-connected net(point symbol:(4^(10).6^(3).8^(2))(4^(3))_(2))and a 3,8-connected tfz-d net(point symbol:(4^(3))_(2)((4^(6).6^(18).8^(4)))),respectively.This structural differentiation confirms the precise regulatory role of ligands on the topology of metal-organic frameworks.Moreover,the ultraviolet-visible absorption spectra confirmed that HU23 and HU24 have strong absorption capabilities for ultraviolet and visible light.According to the Kubelka-Munk method,their bandwidths were 2.15 and 2.08 eV,respectively,which are consistent with those of typical semiconductor materials.Variable-temperature magnetic susceptibility measurements(2-300 K)revealed significant antiferromagnetic coupling in both complexes,with their effective magnetic moments decreasing markedly as the temperature lowered.CCDC:2457554,HU23;2457553,HU24.
基金supported by the National Natural Science Foundation of China(Nos.62104045,52101213)Jiangsu Provincial Department of Science and Technology of China(No.BE2022426).
文摘As the chemical industry expands,the use of benzene,toluene,and xylene(collectively known as BTX)in industrial production has increased greatly.Meanwhile,the toxic nature and potential health hazards of BTX gases cannot be ignored due to low-concentration leaks underline the critical need for rapid and real-time monitoring of these gases.Chemiresistive metal oxide semiconductor(MOS)-based gas sensors,which are extensively used for gas detection in both industrial settings and everyday life,emerge as one of the optimal solutions for trace BTX detection.These sensors are highly valued for their high sensitivity and low detection limits.Nevertheless,the improvement of selectivity towards specific BTX gases to achieve efficient and precise detection still remains challenging.This review summarizes the chemiresistive MOS-based gas sensors designed for BTX detection,categorizing them based on the components of sensing materials-basically into three groups:single-component,single heterojunction,and multiple heterojunctions gas sensing materials.Further,the review proposes the future application prospects of chemiresistive MOS-based BTX gas sensors,with specific emphasis on their significance in promoting industrial safety and environmental monitoring.
文摘39 soil samples surrounding a lead-zinc mining area in Guangxi were collected,and the contents of Pb,Hg,Cd,Cr,As,Cu,Zn,and Ni were determined to investigate the pollution characteristics and sources of heavy metals.ArcGIS inverse distance weight difference method was used to analyze the characteristics of pollution distribution,and single-factor pollution index,Nemerow comprehensive pollution index,ground accumulation index,and potential ecological risk index were selected to evaluate the characteristics of heavy metal pollution.Based on correlation analysis,the absolute principal component-multiple linear regression(APCS-MLR)and positive definite matrix factorization(PMF)models were used to analyze the sources of soil heavy metals.The results showed that the average concentrations of all eight heavy metals exceeded both national and Guangxi soil background values.Hg,Cd,and Zn exhibited high variation(greater than 0.5),indicating significant external disturbances,and their spatial distribution was closely related to mining activity locations.The single-factor pollution index evaluation indicated varying degrees of pollution risk for Cd,Zn,and As,with Cd and Zn being the most severe pollutants,as 69.23%and 30.77%of the samples fell into the moderate pollution or higher category.The geoaccumulation index analysis ranked the mean pollution levels of the eight elements as follows:Zn>Cd>Ni>Pb>Cu>Cr>Hg>As,with Cd and Zn showing the most severe contamination,and 51.28%of the samples exhibiting moderate or higher pollution levels.The Nemerow comprehensive pollution index evaluation showed that 74.35%of soil samples were classified as moderate to heavy pollution.The potential ecological risk index assessment indicated significant ecological risks posed by Cd and Zn,with 82.05%and 5.12%of the samples classified as causing strong to extreme ecological risks,respectively.The source apportionment analysis revealed minor differences between the two models.The APCS-MLR model identified three pollution sources and their contribution rates:anthropogenic mining sources(31.13%),parent material sources(40.38%),and unidentified sources(28.49%).The PMF model identified three pollution sources with contribution rates of anthropogenic mining sources(26.10%),parent material sources(46.96%),and a combined traffic and agricultural source(26.61%).Pb,Hg,Cd,and Zn mainly originated from mining activities;Cr,As,and Ni were primarily derived from the parent material,while Cu was predominantly attributed to traffic and agricultural sources.These findings provide a scientific basis for the prevention and control of heavy metal pollution in mining areas.
基金National MCF Energy R&D Program(2024YFE03260300)。
文摘Refractory metals,including tungsten(W),tantalum(Ta),molybdenum(Mo),and niobium(Nb),play a vital role in industries,such as nuclear energy and aerospace,owing to their exceptional melting temperatures,thermal durability,and corrosion resistance.These metals have body-centered cubic crystal structure,characterized by limited slip systems and impeded dislocation motion,resulting in significant low-temperature brittleness,which poses challenges for the conventional processing.Additive manufacturing technique provides an innovative approach,enabling the production of intricate parts without molds,which significantly improves the efficiency of material usage.This review provides a comprehensive overview of the advancements in additive manufacturing techniques for the production of refractory metals,such as W,Ta,Mo,and Nb,particularly the laser powder bed fusion.In this review,the influence mechanisms of key process parameters(laser power,scan strategy,and powder characteristics)on the evolution of material microstructure,the formation of metallurgical defects,and mechanical properties were discussed.Generally,optimizing powder characteristics,such as sphericity,implementing substrate preheating,and formulating alloying strategies can significantly improve the densification and crack resistance of manufactured parts.Meanwhile,strictly controlling the oxygen impurity content and optimizing the energy density input are also the key factors to achieve the simultaneous improvement in strength and ductility of refractory metals.Although additive manufacturing technique provides an innovative solution for processing refractory metals,critical issues,such as residual stress control,microstructure and performance anisotropy,and process stability,still need to be addressed.This review not only provides a theoretical basis for the additive manufacturing of high-performance refractory metals,but also proposes forward-looking directions for their industrial application.
基金supported by the Basic and Applied Basic Research Foundation of Guangdong province(2024A1515030155 and 2022A1515010272)Natural Science Foundation of China(61904067)+2 种基金Basic and Applied Basic Research Foundation of Guangzhou city(202102020758)Open funding from State Key Laboratory of Optoelectronic Materials and Technologies(Sun Yat-Sen University,OEMT2022-KF-08)Fundamental Research Funds for the Central Universities(11625109,11621405)。
文摘Metals,indispensable since the Bronze Age,remain pivotal in modern technologies due to their exceptional properties and versatility.Beyond traditional machining,advanced nano/micro-machining techniques enable the fabrication of metallic nano/micro structures with high precision in shape,size,and pattern.These structures endow flexible electrodes with outstanding electrical,mechanical,optical,and electrochemical performance,enabling growing applications in flexible optoelectronics,epidermal electronics,energy harvesting,and biochemical sensing.This review provides a comprehensive overview of the fabrication strategies for flexible electrodes made from metal meshes,metal nanowires,and liquid metals.The current advancements,existing challenges,and emerging technologies are systematically discussed.Furthermore,the progression toward ultra-thin,soft epidermal electrodes is explored,with an emphasis on novel in situ and transfer fabrication methods.We examine the underlying mechanisms,performance indicators,and their integration for on-skin applications,including bioelectric sensing,electrical stimulation,and energy harvesting.Finally,we highlight the remaining challenges in performance improvement and industrialization of flexible and epidermal electrodes,along with future opportunities for integrating multimodal systems and leveraging artificial intelligence to enhance their functionalities.
文摘Platinum group metals have high melting points,strong corrosion resistance,stable chemical properties,and low oxygen permeability in high-temperature oxygen-containing environments.As thermal protective coating materials,they have gained essential applications in the aerospace field and have excellent prospects for application in frontier military fields,such as protecting hot-end components of hypersonic aircraft.This research reviewed the latest research progress of platinum group metal coatings with hightemperature oxidation resistance,including coating preparation techniques,oxidation failure,and alloying modification.The leading preparation techniques of current platinum group metal coatings were discussed,as well as the advantages and disadvantages of various existing preparation techniques.Besides,the intrinsic properties,failure forms,and failure mechanisms of coatings of single platinum group metal in high-temperature oxygen-containing environments were analyzed.On this basis,the necessity,main methods,and main achievements of alloying modification of platinum group metals were summarized.Finally,the future development of platinum group coatings with high-temperature oxidation resistance was discussed and prospected.
基金the support of the Shenzhen Science and Technology Program(no.JCYJ20220818100405012)National Natural Science Foundation of China(NSFC,no.62374080)Shenzhen Key Laboratory of Intelligent Manufacturing for Continuous Carbon Fiber Reinforced Composites(no.ZDSYS20220527171404011)。
文摘Composite solid-state electrolytes incorporating metal-organic frameworks(MOFs)demonstrate tremendous potential for ameliorating Li^(+)conduction in lithium metal batteries.However,their practical application is hindered by low ionic co nductivity and unstable Li^(+)transport at the electrode interfaces.To overcome these challenges,a previously unreported family of indium based MOFs(In-BDC-F_(x),x=0,4,6)with tunable fluorine content was synthesized and integrated into PVDF-HFP matrices to construct highperformance quasi-solid-state electrolytes.By systematically modulating linker fluorination,a bifunctional enhancement mechanism is revealed:fluorinated indium centers simultaneously suppress polymer crystallinity and establish preferential Li^(+)conduction pathways.Remarkably,In-BDC-F_(6) manifests exceptional synergistic interactions between-CF_(3) functionalities and indium coordination sites,amplifying Lewis acidity to facilitate LiTFSI dissociation and TFSI-immobilization,culminating in homogeneous LiF-enriched solid electrolyte interphases.The optimized electrolyte demonstrates compelling electrochemical performance:ionic conductivity of 9.68×10^(-4) S cm^(-1),Li^(+)transference number of 0.70,and electrochemical stability window of 4.96 V.Li‖Li symmetric cell demonstrated a critical current density of 3.5 mA cm^(-2) and stable plating/stripping for over 1000 h at 0.2 mA cm^(-2),while LiFePO_(4)‖Li cells retain96.66%capacity after 1300 cycles at 10C,underscoring the transformative potential of fluorinated MOF architectures in fast-charging solid-state batteries.
基金supported by the National Natural Science Foundation of China(Grant No.22175136)the State Key Laboratory of Electrical Insulation and Power Equipment(Grant No.EIPE23127)the Fundamental Research Funds for the Central Universities(xtr052024009,xtr052025002).
文摘Violet phosphorus,a recently explored layered elemental semiconductor,has attracted much attention due to its unique photoelectric,mechanical properties,and high hole mobility.Herein,violet arsenic phosphorus has for the first time been synthesized by a molten lead method.The crystal structure of violet arsenic phosphorus(P^(83.4)As_(0.6),CSD-2408761)was determined by single crystal X-ray diffraction to have similar structure as that of violet phosphorus,where P12 is occupied by arsenic/phosphorus(As/P)atoms as mixed occupancy sites As1/P12.The arsenic substitution has been demonstrated to tune the band structure of violet phosphorus,switching p-type of violet phosphorus to high-performance n-type violet arsenic phosphorus.The effective electron mass along the<010>direction is significantly reduced from 1.792 to 0.515 m_(0)by arsenic substitution,resulting in an extremely high electron mobility of 2622.503 cm^(2)V^(-1)s^(-1).The field effect transistor built with P_(83.4)As_(0.6)nanosheets was measured to have a high electron mobility(137.06 cm^(2)V^(-1)s^(-1),61.2 nm),even under ambient conditions for 5 h,much higher than the hole mobility of violet phosphorene nanosheets(4.07 cm^(2)V^(-1)s^(-1),73.3 nm).This work provides a new idea for designing phosphorus-based materials for field effect transistors,giving significant potential in complementary metal-oxide-semiconductor applications.
基金supported by the Basic Science Research Program(RS-2024-00455177)through the National Research Foundation of Korea(NRF)funded by the Ministry of Science,ICT.
文摘Aqueous zinc ion batteries(AZIBs)are considered promising candidates owing to their inherent safety and low cost.However,the conventional glass fiber(GF)separator used in AZIBs suffers from poor physicochemical properties,leading to uncontrolled zinc(Zn)dendrite formation and undesirable side reactions.To address these limitations and enhance the electrochemical performance of AZIBs,a precisely designed functional separator is developed by incorporating UiO-66-(COOH)_(2)into a poly(vinylidene fluoride)(PVDF)framework(U-PVDF)via a direct in situ growth method.This approach enables uniform distribution of UiO-66-(COOH)_(2)both on the surface and within the PVDF backbone,without increasing separator thickness.Owing to the strong interaction between Zn^(2+)and the abundant carboxyl groups in UiO-66-(COOH)_(2),the U-PVDF separator regulates the Zn^(2+)solvation structure toward a contact ion pair-dominated structure by reducing coordinated water molecules,which effectively mitigates water-induced parasitic reactions and promotes compact Zn deposition.Consequently,a Zn/Zn symmetric cell employing the U-PVDF separator demonstrates superior cycling stability over 1500 cycles without internal short-circuiting at a current density of 6 mA cm^(−2)and an areal capacity of 2 mAh cm^(−2).Moreover,Zn/NaV_(3)O_(8)·xH_(2)O(NVO)cell with the U-PVDF separator exhibits markedly improved cyclability and rate performance compared with those using conventional GF separator.
基金Project supported by the National Natural Science Foundation of China(No.12402113)the Sichuan Science and Technology Program(No.2024NSFSC0037)。
文摘Piezoelectric semiconductor(PSC)materials exhibit strong electromechanical coupling affected by free carriers,which makes their contact behavior essential for sensors,actuators,and electronic devices.Analytical models for three-dimensional(3D)PSC contact problems are still scarce,especially for conductive indenters.This work develops a semi-analytical framework to study the 3D frictionless contact between a conductive indenter and a PSC half-space.Fundamental solutions under a unit force and a unit electric charge are derived,and the corresponding frequency response functions are combined with a discrete convolution-fast Fourier transform(DC-FFT)algorithm to achieve an efficient semi-analytical contact model.The numerical results demonstrate that an increase in the surface charge density reduces the indentation pressure and modifies the electric potential distribution.A higher steady carrier concentration enhances the screening effect,suppresses the electromechanical coupling,and shifts the system response toward purely elastic behaviors.The sensitivity analysis shows that the indentation depth is dominated by the elastic constants,while the electric potential is mainly affected by the piezoelectric coefficient.Although the analysis is carried out with spherical indenters,the model is not limited to a specific indenter shape.It provides an effective tool for investigating complex 3D PSC contact problems and offers useful insights into the design of PSC materials-based devices.
基金supported by the National Key Research and Development Program of China(Grant Nos.2024YFA1611102,2022YFA1403903,2023YFA1406101,and 2022YFA1204100)the National Natural Science Foundation of China(Grant Nos.12304075 and 62488201)+1 种基金CAS Project for Young Scientists in Basic Research(Grant Nos.2022YSBR-048 and YSBR-003)the Innovation Program of Quantum Science and Technology(Grant No.2021ZD0302700)。
文摘We present a systematic investigation of the superconductivity in high-quality CsTi_(3)Bi_(5) single crystals by combining bulk property characterization and local-probe spectroscopy.Two successive superconducting transitions are observed in this newly discovered kagome material.In the first stage,the diamagnetic response strengthens significantly from T_(c)~4.9 K to 4.6 K,followed by a broad transition below 4.6 K in the second stage.Moreover,different magnetic field dependences are observed for the two stages,where the first stage is field-insensitive while the second stage exhibits strong field dependence.The ultra-low magnetic field measurements indicate that the lower critical field H_(c1)(T)exhibits small anisotropy.Based on a comparative study of the superconducting state in CsBi2 and microscopic verification via scanning tunneling microscopy(STM),our results suggest the emergence of exotic and intrinsic superconductivity in this new titanium-based kagome superconductor,establishing it as a promising platform for further exploring the complexity of electronic states in the kagome lattice.
基金Supported by Undergraduate Innovation and Entrepreneurship Training Program of Guizhou Province(2024106640823)Natural Science Research Project of Guizhou Provincial Department of Education(QJJ[2023]043)Zunyi Science and Technology Innovation Team Project(ZKCTD008).
文摘[Objectives]To analyze the current status of heavy metal contamination in soils of vegetable cultivation bases located in Huichuan District,Zunyi City.[Methods]Soil samples from various depths within the vegetable cultivation bases of Guanba Village,Sidu Village,and Banqiao Village in Huichuan District,Zunyi City,were selected as the subjects of this study.The concentrations of five heavy metals,including lead(Pb),mercury(Hg),cadmium(Cd),arsenic(As),and chromium(Cr),were measured at different soil depths.The Nemerow comprehensive pollution index method was employed to assess heavy metal contamination,and the analysis was conducted in accordance with the farmland environmental quality evaluation standards for edible agricultural products.[Results]The concentrations of Cd and As at the sample collection sites were relatively elevated.The pollution level of Cd reached grade III or above,indicating moderate contamination in certain topsoil areas.Most As concentrations corresponded to grade II and grade III pollution levels.In contrast,Hg,Pb,and Cr concentrations remained within the safety standards established for agricultural products.However,Cd and As levels predominantly surpassed these safety thresholds.Notably,Guanba Village and Sidu Village exhibited significant pollution levels,warranting comprehensive investigations into the sources of contamination.[Conclusions]This study offers valuable insights for advancing the sustainable development of local agriculture and for the prevention and management of soil contamination.
基金supported by the Natural Science Foundation of Jiangsu Province(No.BK20220409)the National Natural Science Foundation of China(No.22401153)+2 种基金the FWO[Fund for Scientific Research-Flanders(Belgium)]for financial support(recipient Erik V.Van der Eycken)the Research Council of the KU Leuven(recipient Erik V.Van der Eycken)the support of the"RUDN University Strategic Academic Leadership Program"(recipient Erik V.Van der Eycken).
文摘Peptides play important roles in chemistry,medicinal chemistry and life science,due to their high efficiency and specificity,unusual biological and therapeutic properties.As naturally occurring peptides often face with their intrinsic limitations including metabolic instability and low membrane permeability,the strategies for synthesizing unnatural amino acids and peptides are explored.Among the methods for modifying amino acids and peptides,chemo-and site-selective approaches are preferred because of the ability to fine-tuning structural features.Recently,transition metal-catalyzed Csingle bondH activation has been employed for the functionalization of amino acids and peptides.Through domino Csingle bondH activation/annulation,a series of structurally complex and diverse amino acids and peptides is constructed.This review highlights recent advances in the synthesis of unnatural amino acids and peptides via transition metal-catalyzed Csingle bondH activation/annulation.
基金Project supported by the National Natural Science Foundation of China(Nos.U21A20430 and 12472155)the Natural Science Foundation of Hebei Province of China(No.A2024210002)。
文摘Due to the intrinsic interaction between piezoelectric effects and semiconducting properties,piezoelectric semiconductors(PSs)have great promise for applications in multi-functional electronic devices,requiring a deep understanding of the multi-field coupling behavior.This work investigates the free vibration and buckling characteristics of a PS beam under different mechanical boundary conditions.The coupling fields of a PS beam are modeled by combining the Timoshenko beam theory for mechanical fields with a high-order expansion along the beam thickness for electric fields and carrier distributions.Based on the hypothesis of small perturbation of carrier density,the governing equations and boundary conditions are derived with the principle of virtual work.The differential quadrature method(DQM)is used to solve the boundary-value problem.The analytical solutions for a simply supported-simply supported(SS)PS beam are also obtained for verification.The convergence and correctness of the solutions obtained with the DQM are first evaluated.Subsequently,the effects of initial electron density,boundary conditions,and geometric parameters on the vibration and buckling characteristics are explored through numerical examples,where the finite element simulations are also included.The interaction mechanism of multi-physics fields is revealed.The scale effect on the static and dynamic responses of a PS beam is demonstrated.The derived model and findings are useful for the analysis and design of PS-based devices.
