The escalating pace of industrialization has significantly intensified water pollution challenges,for instance,the persistent organic pollutants like methyl orange(MO).Conventional remediation techniques,such as adsor...The escalating pace of industrialization has significantly intensified water pollution challenges,for instance,the persistent organic pollutants like methyl orange(MO).Conventional remediation techniques,such as adsorption and biological degradation,are often hampered by low efficiency and the risk of secondary pollution.Photocatalysis emerges as a promising sustainable alternative;however,the benchmark material titanium dioxide(TiO_(2))suffers from its intrinsic limitations,notably its wide bandgap energy(≥3.4 eV)restricting its activity to the region of the ultraviolet light and its rapid recombination of photogenerated charge carriers.To overcome these constraints,this research focused on synthesizing novel TiO_(2)/Sn_(3)O_(4) heterojunction composite photocatalysts via a solvothermal approach.Comprehensive characterization techniques confirmed the successful formation of the composite,which revealed that ultrathin Sn3O4 nanosheets uniformly coated TiO_(2) nanospheres.This unique architecture effectively reduced the overall crystallinity and introduced the beneficial oxygen vacancies.Under visible-light irradiation(λ≥420 nm),the optimized TiO_(2)/Sn3O4 composite exhibited the exceptional photocatalytic performance,which achieved 96%degradation of MO within just 60 minutes.The calculated apparent kinetic rate constant(0.103 min^(-1))was remarkably(5.15 times)higher than that of pristine TiO_(2).ESR experiments identified that hydroxyl radicals(·OH)was the predominant active species driving the degradation.Furthermore,cyclic degradation tests demonstrated its excellent material stability,with the composite retaining 85%of its initial efficiency after four consecutive reuse cycles.This work underscored the synergistic effects within the TiO_(2)/Sn_(3)O_(4) heterojunction,which significantly enhanced the visible-light absorption,charge separation,and photocatalytic activity,which provided the valuable insights for designing efficient,stable catalysts for the advanced environmental remediation applications.展开更多
Inorganic materials can solve transportable and on-site hydrolytic hydrogen generation issues.CaH_(2)/(Al/Si)composites are preferable due to their notable chemical properties.However,these composites require pretreat...Inorganic materials can solve transportable and on-site hydrolytic hydrogen generation issues.CaH_(2)/(Al/Si)composites are preferable due to their notable chemical properties.However,these composites require pretreatments,an inert environment,and long hours of physical ball milling for high homogeneity and synergistic effects.CaH_(2)also inhibits the hydrolysis reaction by forming its products on the Al/Si surface,which hinders the direct utilization of composites.This work represents the first investigation of NaH-CaH_(2)(Al/Si)fuel composites,which greatly overcome these limitations and can be directly used for on-site hydrogen generation and proton exchange membrane(PEM)fuel cells.The NaH-CaH_(2)(Al/Si)fuel composites were prepared by using a straightforward mixing method with variable composition ratios,showing high H_(2)yield and fuel cell(FC)performance.NaH addition provides the bridge effect,which opens up a new way to enable efficient hydrolysis and greatly enhances the hydrolysis activity of CaH_(2)/(Al/Si)composites.The novel fuel composites(NaH-CaH_(2)/Al)have extraordinary FC performance and a 0.42 W/cm2 peak power density greater than commercial hydrogen generators.It provides high H_(2)yield 84.4%for NaH-CaH_(2)/Al and 82%for NaH-CaH_(2)/Si compared to NaOH-CaH_(2)(Al/Si),NaCl-CaH_(2)(Al/Si),and KCl-CaH_(2)(Al/Si)composites.The NaH bridge effect hinders the direct water contact and stops the formation of Ca(OH)2 around Al/Si,which provides adequate pathways for the CaH_(2)(Al/Si)hydrolysis.The impressive capabilities of novel fuel composites are anticipated to offer practical uses in fuel cells,automobile applications,and portable/on-board H_(2)generation.展开更多
The aim of the present paper is to study 2-complex symmetric bounded weighted composition operators on the Fock space of C^(N) with the conjugations J and J_(t,A,b) defined by ■ respectively,where k(z_(1),...,z_N)=(...The aim of the present paper is to study 2-complex symmetric bounded weighted composition operators on the Fock space of C^(N) with the conjugations J and J_(t,A,b) defined by ■ respectively,where k(z_(1),...,z_N)=(■,...,■),t∈C,b∈C^(N) and A is a linear operator on C^(N).An example of 2-complex symmetric bounded weighted composition operator with the conjugation J_(t,A,b) is given.展开更多
Photocatalysis is an important process in energy conversion and environmental usage because of its feasible,profitable,and environmentally safe benefits.Coordination chemistry of the CeO_(2)is gaining significant inte...Photocatalysis is an important process in energy conversion and environmental usage because of its feasible,profitable,and environmentally safe benefits.Coordination chemistry of the CeO_(2)is gaining significant interest because its nanocomposites show unique characteristics namely optically active,wide bandgap(Eg),reversible valence states(Ce^(3+/4+)),rich defect architectures,high O_(2)storage capability,ionic conductivity,and exceptional chemical resistance.Systematically summarized the importance of synthesis methods,particle morphology,and crystal structure aiming at how to heighten the efficacy of CeO_(2)-derived hybrid heterojunction(HHJ)photocatalyst.Selection of an appropriate synthesis method and morphology of the composite materials are beneficial in inhibiting the rapid electron-hole(e^(−)-h^(+))recombination,improvement in visible light adsorption,and large generation of e^(−)-h^(+)pairs to accelerate the photocatalysts activities.Various modification approaches include elemental doping(metal/non-metal doping),heterojunction construction(lower/wide Eg semiconductors(SCD),carbon,conducting polymeric materials),imperfection engineering,and multicomponent hybrid composites.These methods assist as a valuable resource for the rational design of effective CeO_(2)-based composite photocatalysts for sustainable development owing to the enhancement of oxygen species mobility,rapid charge transfer,maximum visible light captivation and slow down the charge recombination rate with increase photogeneration of e−-h+pairs.Also examines the advancements made in CeO_(2)conjugated hybrid composites in photo-oxidation of wastewater effluents(antibiotic/organic dyes/chemical/pharmaceutical),heavy metal removal,H2 production,CO_(2)reduction,and H2O splitting applications.Subsequently,the difficulties and fundamental ideas behind several heterojunction photocatalysts encountered by CeO_(2)-based composites are examined,and future directions for their development are suggested.展开更多
Unmanaged wood waste,particularly in countries like Nepal,presents serious environmental concerns due to open burning and improper disposal,leading to carbon emissions,air pollution and land degradation.This study int...Unmanaged wood waste,particularly in countries like Nepal,presents serious environmental concerns due to open burning and improper disposal,leading to carbon emissions,air pollution and land degradation.This study introduces an environmentally sustainable strategy to upcycle Toona ciliata wood scrap—an abundant and underutilized lignocellulosic biomass—into high performance carbon electrodes for green energy storage applications.Activated carbon(TCWAC)was synthesized via single-step pyrolytic carbonization followed by phosphoric acid activation,yielding a material with high specific surface area,hierarchical porosity,and excellent electrical conductivity.Electrochemical measurements using a three-electrode configuration in 6 M KOH revealed optimized potential windows of -1.0 to -0.2 V(TCWAC),-1.2 to 0 V(TCWAC-Mn),and -1.15 to -0.4 V(TCWAC-Fe).TCWAC exhibited a specific capacitance of 156.3 Fg^(-1)at 1 Ag^(-1),with an energy density of 3.5 Whkg^(-1),and 80.2% capacity retention after 1000 charge-discharge cycles.Composites with MnO_(2)and Fe_(2)O_(3)were also evaluated.TWAC-Mn delivered 489.4 Fg^(-1),25.1 Whkg^(-1),and 99.1% retention,whereas,TWAC-Fe achieved 321.3 Fg^(-1),6.3 Whkg^(-1),and 90.3% retention.The superior performance of MnO_(2)is attributed to its multiple oxidation states,facilitating reversible faradaic redox and enhanced pseudocapacitance.This work offers the first direct,systematic comparison of MnO_(2)and Fe_(2)O_(3)composites on a common biomass-carbon matrix under identical synthesis and testing conditions.The finding provides mechanistic insight into charge storage behaviour and demonstrate a scalable route for converting biomass waste into sustainable electrode materials,contributing to cleaner energy solutions and improved biomass valorization.展开更多
The photovoltaic properties of indium–gallium–zinc oxide(IGZO)thin film utilized in electronic information applications depend on the quality and performance of the corresponding target.In this study,high-energy bal...The photovoltaic properties of indium–gallium–zinc oxide(IGZO)thin film utilized in electronic information applications depend on the quality and performance of the corresponding target.In this study,high-energy ball milling was combined with atmospheric sintering to achieve precise control over the phase composition and microstructure of In_(2)Ga_(2)ZnO_(7) ceramic targets.This was achieved by controlling the sintering process and performing thermodynamic calculations to analyze the phase transition process.Further,the electronic structure simulation results of the relevant phases were analyzed,and crystal structure models were constructed.According to the density functional theory calculations,the enthalpy of formation of In_(2)Ga_(2)ZnO_(7) was found to be the largest,followed by those of InGaZnO_(4) and ZnGa_(2)O_(4),which indicates that the In_(2)Ga_(2)ZnO_(7) phase exhibits the highest thermal stability.The relationship of the enthalpy of formation corresponds to two distinct reactions of the IGZO powders.The ZnGa_(2)O_(4) phase is initially formed and remains stable for an extended period.This is followed by the rapid formation and subsequent disappearance of the InGaZnO_(4) phase within a narrow temperature range.Finally,a single In_(2)Ga_(2)ZnO_(7) phase is formed.The target sintered at 1500℃ exhibits a narrow band gap and the lowest porosity,which results in the highest relative density(99.52%)and the lowest resistivity(3.4 mΩ·cm).These experimental findings can provide guidelines for controlling the phase and microstructural characteristics of In_(2)Ga_(2)ZnO_(7) targets with the aim of producing IGZO targets with excellent properties,including homogeneous composition,high density,and low resistance in the field of flat displays.展开更多
CuIn（S,Se）2 thin films were prepared by thermal crystallization of co-sputtered Cu-In alloy precursors in S/Se atmosphere. In-depth compositional uniformity is an important prereq- uisite for obtaining device-qualit...CuIn（S,Se）2 thin films were prepared by thermal crystallization of co-sputtered Cu-In alloy precursors in S/Se atmosphere. In-depth compositional uniformity is an important prereq- uisite for obtaining device-quality CuIn（S,Se）2 absorber thin films. In order to figure out the influence of heat treatments on in-depth composition uniformity of CuIn（S,Se）2 thin films, two kinds of reaction temperature profiles were investigated. One process is ＂one step profile＂, referring to formation of CuIn（S,Se）2 thin films just at elevated temperature （e.g. 500 ℃）. The other is ＂two step profile＂, which allows for slow diffusion of S and Se elements into the alloy precursors at a low temperature before the formation and re-crystallization of CuIn（S,Se）2 thin films at higher temperature （e.g. first 250 ℃ then 500 ℃）. X-ray diffrac- tion studies reveal that there is a discrepancy in the shape of （112） peak. Samples annealed with ＂one step profile＂ have splits on （112） peaks, while samples annealed with ＂two step profile＂ have relatively symmetrical （112） peaks. Grazing incident X-ray diffraction and en- ergy dispersive spectrum measurements of samples successively etched in bromine methanol show that CuIn（S,Se）2 thin films have better in-depth composition uniformity after ＂two step profile＂ annealing. The reaction mechanism during the two thermal processing was also investigated by X-ray diffraction and Raman spectra.展开更多
To mitigate secondary electromagnetic pollution,there is an urgent need to develop absorption-dominant electromagnetic interference(EMI)shielding materials with low density,reduced thickness,lightweight construction,f...To mitigate secondary electromagnetic pollution,there is an urgent need to develop absorption-dominant electromagnetic interference(EMI)shielding materials with low density,reduced thickness,lightweight construction,flexibility,exceptional mechanical strength,and superior electrothermal and photothermal properties,particularly for flexible and wearable electronics.In this regard,we designed an absorption-based composite film comprising carbon nanotubes(CNT)and α-Fe_(2)O_(3),featuring a CNT layer sandwiched between twoα-Fe_(2)O_(3)layers on the upper and lower surfaces.This composite film was fabricated through an electrodeposition process followed by a thermal annealing procedure to achieve enhanced EMI shielding performance along with improved electrothermal and photothermal properties.The strategically designed sandwich structure allows the rough surface of the upper α-Fe_(2)O_(3)layer to not only improve the impedance mismatch between free space and the composite film,facilitating the penetration of incident electromagnetic(EM)waves into the film and promoting increased EM absorption rather than reflection,but also to enhance electrical conductivity,thereby improving electron mobility and density.Consequently,the average total shielding effectiveness(SE)of the CNT/Fe_(16)-300 composite demonstrates remarkable EMI shielding effectiveness(EMI SE:56.8 dB).Furthermore,the alteration in the absorption-to-reflection ratio(A/R)signifies a transition in the EMI shielding mechanism from reflection(0.69 for the pristine CNT film)to absorption(1.86 for the CNT/Fe_(16)-300)with the incremental deposition of α-Fe_(2)O_(3)nanoparticles.This work presents a feasible manufacturing approach for developing composite films with a sandwich structure that exhibits absorption-dominant EMI shielding capabilities,contributing to advancements in thermal management and multifunctional electromagnetic shielding applications.展开更多
[Objective] To compare the regional differences of the conventional chemi- cal compositions in the K326 B2F tobacco from different tobacco-planting areas of Yunnan Province. [Methed] Continuous flow analyzer was used ...[Objective] To compare the regional differences of the conventional chemi- cal compositions in the K326 B2F tobacco from different tobacco-planting areas of Yunnan Province. [Methed] Continuous flow analyzer was used to detect the con- ventional chemical compositions, and SPSS 17.0 statistical package was used to conduct data statistical analysis and variance analysis. [Result] Significant differences were existed among most of the indicators for conventional chemical compositions of K326 tobacco in different areas： the differences of total sugar, reducing sugar and nicotine reached a high Significant level; potassium ion and total nitrogen differences reached a significant level, while there was no significant difference in chlorine ion. Most of the conventional chemical compositions in K326 B2F tabacco planted in Yuxi region and those planted in Qujing, Dali and Chuxiong were significantly different. The total sugar, reducing sugar and nicotine contents of tobacco planted in eastern Yunnan, central Yunnan and western Yunnan were significantly different; while the conventional chemical compositions contents in the tobacco planted in Chuxiong and Dali, which all belong to western Yunnan, showed no obvious significant difference, indicating different ecological environments in large area had a great impact on the tobacco of Yunnan Province. [Conclusion] It revealed the regional characteristics of the conventional chemical compositions in K326 flue-cured tobacco leaves from Yunnan Province, providing references for the cigarette blending and production of high-quality tobacco with characteristics.展开更多
Molybdenum disulfide(MoS2)was loaded on biocarbon using waste camellia dregs(CDs)as the carbon source,which was further coated with dopamine hydrochloride to construct biocarbon/MoS2 electrode composites.The electroch...Molybdenum disulfide(MoS2)was loaded on biocarbon using waste camellia dregs(CDs)as the carbon source,which was further coated with dopamine hydrochloride to construct biocarbon/MoS2 electrode composites.The electrochemical lithium storage performance of the composites with different MoS2 contents was investigated.SEM results demonstrated that the composite had a three-dimensional foam-like structure with MoS2 as the interlayer.XRD and HRTEM tests revealed that MoS2 interlayer spacing in the composite was expanded.XPS analysis showed that new Mo—N bonds were formed in the active material.The electrochemical tests showed that the composite with a MoS2 content of 63%had a high initial specific capacity of 1434 mA·h/g at a current density of 100 mA/g.After a long cycle at a high current,it also showed good cycling stability and the capacity retention was nearly 100%.In addition,it had good lithium ion deintercalation ability in the electrochemical kinetics test.展开更多
文摘The escalating pace of industrialization has significantly intensified water pollution challenges,for instance,the persistent organic pollutants like methyl orange(MO).Conventional remediation techniques,such as adsorption and biological degradation,are often hampered by low efficiency and the risk of secondary pollution.Photocatalysis emerges as a promising sustainable alternative;however,the benchmark material titanium dioxide(TiO_(2))suffers from its intrinsic limitations,notably its wide bandgap energy(≥3.4 eV)restricting its activity to the region of the ultraviolet light and its rapid recombination of photogenerated charge carriers.To overcome these constraints,this research focused on synthesizing novel TiO_(2)/Sn_(3)O_(4) heterojunction composite photocatalysts via a solvothermal approach.Comprehensive characterization techniques confirmed the successful formation of the composite,which revealed that ultrathin Sn3O4 nanosheets uniformly coated TiO_(2) nanospheres.This unique architecture effectively reduced the overall crystallinity and introduced the beneficial oxygen vacancies.Under visible-light irradiation(λ≥420 nm),the optimized TiO_(2)/Sn3O4 composite exhibited the exceptional photocatalytic performance,which achieved 96%degradation of MO within just 60 minutes.The calculated apparent kinetic rate constant(0.103 min^(-1))was remarkably(5.15 times)higher than that of pristine TiO_(2).ESR experiments identified that hydroxyl radicals(·OH)was the predominant active species driving the degradation.Furthermore,cyclic degradation tests demonstrated its excellent material stability,with the composite retaining 85%of its initial efficiency after four consecutive reuse cycles.This work underscored the synergistic effects within the TiO_(2)/Sn_(3)O_(4) heterojunction,which significantly enhanced the visible-light absorption,charge separation,and photocatalytic activity,which provided the valuable insights for designing efficient,stable catalysts for the advanced environmental remediation applications.
基金financial support granted by the National Natural Science Foundation of China (No. 22402225)the Gusu Innovation and Entrepreneurship Leading Talent Plan(No. ZXL2023193)+2 种基金the Sinano Talents Plan (No. 2022000175)the Guangdong Basic and Applied Basic Research Foundation (No.2023A1515111133)the ANSO Scholarship for Young Talents
文摘Inorganic materials can solve transportable and on-site hydrolytic hydrogen generation issues.CaH_(2)/(Al/Si)composites are preferable due to their notable chemical properties.However,these composites require pretreatments,an inert environment,and long hours of physical ball milling for high homogeneity and synergistic effects.CaH_(2)also inhibits the hydrolysis reaction by forming its products on the Al/Si surface,which hinders the direct utilization of composites.This work represents the first investigation of NaH-CaH_(2)(Al/Si)fuel composites,which greatly overcome these limitations and can be directly used for on-site hydrogen generation and proton exchange membrane(PEM)fuel cells.The NaH-CaH_(2)(Al/Si)fuel composites were prepared by using a straightforward mixing method with variable composition ratios,showing high H_(2)yield and fuel cell(FC)performance.NaH addition provides the bridge effect,which opens up a new way to enable efficient hydrolysis and greatly enhances the hydrolysis activity of CaH_(2)/(Al/Si)composites.The novel fuel composites(NaH-CaH_(2)/Al)have extraordinary FC performance and a 0.42 W/cm2 peak power density greater than commercial hydrogen generators.It provides high H_(2)yield 84.4%for NaH-CaH_(2)/Al and 82%for NaH-CaH_(2)/Si compared to NaOH-CaH_(2)(Al/Si),NaCl-CaH_(2)(Al/Si),and KCl-CaH_(2)(Al/Si)composites.The NaH bridge effect hinders the direct water contact and stops the formation of Ca(OH)2 around Al/Si,which provides adequate pathways for the CaH_(2)(Al/Si)hydrolysis.The impressive capabilities of novel fuel composites are anticipated to offer practical uses in fuel cells,automobile applications,and portable/on-board H_(2)generation.
基金Supported by Sichuan Science and Technology Program (No.2022ZYD0010)。
文摘The aim of the present paper is to study 2-complex symmetric bounded weighted composition operators on the Fock space of C^(N) with the conjugations J and J_(t,A,b) defined by ■ respectively,where k(z_(1),...,z_N)=(■,...,■),t∈C,b∈C^(N) and A is a linear operator on C^(N).An example of 2-complex symmetric bounded weighted composition operator with the conjugation J_(t,A,b) is given.
文摘Photocatalysis is an important process in energy conversion and environmental usage because of its feasible,profitable,and environmentally safe benefits.Coordination chemistry of the CeO_(2)is gaining significant interest because its nanocomposites show unique characteristics namely optically active,wide bandgap(Eg),reversible valence states(Ce^(3+/4+)),rich defect architectures,high O_(2)storage capability,ionic conductivity,and exceptional chemical resistance.Systematically summarized the importance of synthesis methods,particle morphology,and crystal structure aiming at how to heighten the efficacy of CeO_(2)-derived hybrid heterojunction(HHJ)photocatalyst.Selection of an appropriate synthesis method and morphology of the composite materials are beneficial in inhibiting the rapid electron-hole(e^(−)-h^(+))recombination,improvement in visible light adsorption,and large generation of e^(−)-h^(+)pairs to accelerate the photocatalysts activities.Various modification approaches include elemental doping(metal/non-metal doping),heterojunction construction(lower/wide Eg semiconductors(SCD),carbon,conducting polymeric materials),imperfection engineering,and multicomponent hybrid composites.These methods assist as a valuable resource for the rational design of effective CeO_(2)-based composite photocatalysts for sustainable development owing to the enhancement of oxygen species mobility,rapid charge transfer,maximum visible light captivation and slow down the charge recombination rate with increase photogeneration of e−-h+pairs.Also examines the advancements made in CeO_(2)conjugated hybrid composites in photo-oxidation of wastewater effluents(antibiotic/organic dyes/chemical/pharmaceutical),heavy metal removal,H2 production,CO_(2)reduction,and H2O splitting applications.Subsequently,the difficulties and fundamental ideas behind several heterojunction photocatalysts encountered by CeO_(2)-based composites are examined,and future directions for their development are suggested.
文摘Unmanaged wood waste,particularly in countries like Nepal,presents serious environmental concerns due to open burning and improper disposal,leading to carbon emissions,air pollution and land degradation.This study introduces an environmentally sustainable strategy to upcycle Toona ciliata wood scrap—an abundant and underutilized lignocellulosic biomass—into high performance carbon electrodes for green energy storage applications.Activated carbon(TCWAC)was synthesized via single-step pyrolytic carbonization followed by phosphoric acid activation,yielding a material with high specific surface area,hierarchical porosity,and excellent electrical conductivity.Electrochemical measurements using a three-electrode configuration in 6 M KOH revealed optimized potential windows of -1.0 to -0.2 V(TCWAC),-1.2 to 0 V(TCWAC-Mn),and -1.15 to -0.4 V(TCWAC-Fe).TCWAC exhibited a specific capacitance of 156.3 Fg^(-1)at 1 Ag^(-1),with an energy density of 3.5 Whkg^(-1),and 80.2% capacity retention after 1000 charge-discharge cycles.Composites with MnO_(2)and Fe_(2)O_(3)were also evaluated.TWAC-Mn delivered 489.4 Fg^(-1),25.1 Whkg^(-1),and 99.1% retention,whereas,TWAC-Fe achieved 321.3 Fg^(-1),6.3 Whkg^(-1),and 90.3% retention.The superior performance of MnO_(2)is attributed to its multiple oxidation states,facilitating reversible faradaic redox and enhanced pseudocapacitance.This work offers the first direct,systematic comparison of MnO_(2)and Fe_(2)O_(3)composites on a common biomass-carbon matrix under identical synthesis and testing conditions.The finding provides mechanistic insight into charge storage behaviour and demonstrate a scalable route for converting biomass waste into sustainable electrode materials,contributing to cleaner energy solutions and improved biomass valorization.
基金supported by the Natural Science Foundation of Henan Province(No.242300421221)the Project of Zhongyuan Critical Metals Laboratory(No.GJJSGFJQ202301)Henan Research Institute 2024 Strategic Consulting Research Project(No.2024 HENZDA01).
文摘The photovoltaic properties of indium–gallium–zinc oxide(IGZO)thin film utilized in electronic information applications depend on the quality and performance of the corresponding target.In this study,high-energy ball milling was combined with atmospheric sintering to achieve precise control over the phase composition and microstructure of In_(2)Ga_(2)ZnO_(7) ceramic targets.This was achieved by controlling the sintering process and performing thermodynamic calculations to analyze the phase transition process.Further,the electronic structure simulation results of the relevant phases were analyzed,and crystal structure models were constructed.According to the density functional theory calculations,the enthalpy of formation of In_(2)Ga_(2)ZnO_(7) was found to be the largest,followed by those of InGaZnO_(4) and ZnGa_(2)O_(4),which indicates that the In_(2)Ga_(2)ZnO_(7) phase exhibits the highest thermal stability.The relationship of the enthalpy of formation corresponds to two distinct reactions of the IGZO powders.The ZnGa_(2)O_(4) phase is initially formed and remains stable for an extended period.This is followed by the rapid formation and subsequent disappearance of the InGaZnO_(4) phase within a narrow temperature range.Finally,a single In_(2)Ga_(2)ZnO_(7) phase is formed.The target sintered at 1500℃ exhibits a narrow band gap and the lowest porosity,which results in the highest relative density(99.52%)and the lowest resistivity(3.4 mΩ·cm).These experimental findings can provide guidelines for controlling the phase and microstructural characteristics of In_(2)Ga_(2)ZnO_(7) targets with the aim of producing IGZO targets with excellent properties,including homogeneous composition,high density,and low resistance in the field of flat displays.
文摘CuIn（S,Se）2 thin films were prepared by thermal crystallization of co-sputtered Cu-In alloy precursors in S/Se atmosphere. In-depth compositional uniformity is an important prereq- uisite for obtaining device-quality CuIn（S,Se）2 absorber thin films. In order to figure out the influence of heat treatments on in-depth composition uniformity of CuIn（S,Se）2 thin films, two kinds of reaction temperature profiles were investigated. One process is ＂one step profile＂, referring to formation of CuIn（S,Se）2 thin films just at elevated temperature （e.g. 500 ℃）. The other is ＂two step profile＂, which allows for slow diffusion of S and Se elements into the alloy precursors at a low temperature before the formation and re-crystallization of CuIn（S,Se）2 thin films at higher temperature （e.g. first 250 ℃ then 500 ℃）. X-ray diffrac- tion studies reveal that there is a discrepancy in the shape of （112） peak. Samples annealed with ＂one step profile＂ have splits on （112） peaks, while samples annealed with ＂two step profile＂ have relatively symmetrical （112） peaks. Grazing incident X-ray diffraction and en- ergy dispersive spectrum measurements of samples successively etched in bromine methanol show that CuIn（S,Se）2 thin films have better in-depth composition uniformity after ＂two step profile＂ annealing. The reaction mechanism during the two thermal processing was also investigated by X-ray diffraction and Raman spectra.
基金financially supported by the National Natural Science Foundation of China(Nos.52222202 and 51772310)Chinese Academy of Sciences Key Research Program of Frontier Sciences(No.QYZDY-SSWJSC031)Shanghai Pilot Program for Basic Research-Chinese Academy of Science,Shanghai Branch(No.JCYJ-SHFY-2021-001).
文摘To mitigate secondary electromagnetic pollution,there is an urgent need to develop absorption-dominant electromagnetic interference(EMI)shielding materials with low density,reduced thickness,lightweight construction,flexibility,exceptional mechanical strength,and superior electrothermal and photothermal properties,particularly for flexible and wearable electronics.In this regard,we designed an absorption-based composite film comprising carbon nanotubes(CNT)and α-Fe_(2)O_(3),featuring a CNT layer sandwiched between twoα-Fe_(2)O_(3)layers on the upper and lower surfaces.This composite film was fabricated through an electrodeposition process followed by a thermal annealing procedure to achieve enhanced EMI shielding performance along with improved electrothermal and photothermal properties.The strategically designed sandwich structure allows the rough surface of the upper α-Fe_(2)O_(3)layer to not only improve the impedance mismatch between free space and the composite film,facilitating the penetration of incident electromagnetic(EM)waves into the film and promoting increased EM absorption rather than reflection,but also to enhance electrical conductivity,thereby improving electron mobility and density.Consequently,the average total shielding effectiveness(SE)of the CNT/Fe_(16)-300 composite demonstrates remarkable EMI shielding effectiveness(EMI SE:56.8 dB).Furthermore,the alteration in the absorption-to-reflection ratio(A/R)signifies a transition in the EMI shielding mechanism from reflection(0.69 for the pristine CNT film)to absorption(1.86 for the CNT/Fe_(16)-300)with the incremental deposition of α-Fe_(2)O_(3)nanoparticles.This work presents a feasible manufacturing approach for developing composite films with a sandwich structure that exhibits absorption-dominant EMI shielding capabilities,contributing to advancements in thermal management and multifunctional electromagnetic shielding applications.
基金Supported by the Science and Technology Project of Yunnan Reascend Tobacco Technology(Group)Co.,Ltd.(2010RS06)the Science and Technology Project of China Tobacco Yunnan Industrial Co.,Ltd.(2008YL07,2009YL02-2)the Science and Technology Project of HONGYUNHONGHE Tobacco(Group)Co.,Ltd.,(YHH2010-YL02,YHH2010YL04)~~
文摘[Objective] To compare the regional differences of the conventional chemi- cal compositions in the K326 B2F tobacco from different tobacco-planting areas of Yunnan Province. [Methed] Continuous flow analyzer was used to detect the con- ventional chemical compositions, and SPSS 17.0 statistical package was used to conduct data statistical analysis and variance analysis. [Result] Significant differences were existed among most of the indicators for conventional chemical compositions of K326 tobacco in different areas： the differences of total sugar, reducing sugar and nicotine reached a high Significant level; potassium ion and total nitrogen differences reached a significant level, while there was no significant difference in chlorine ion. Most of the conventional chemical compositions in K326 B2F tabacco planted in Yuxi region and those planted in Qujing, Dali and Chuxiong were significantly different. The total sugar, reducing sugar and nicotine contents of tobacco planted in eastern Yunnan, central Yunnan and western Yunnan were significantly different; while the conventional chemical compositions contents in the tobacco planted in Chuxiong and Dali, which all belong to western Yunnan, showed no obvious significant difference, indicating different ecological environments in large area had a great impact on the tobacco of Yunnan Province. [Conclusion] It revealed the regional characteristics of the conventional chemical compositions in K326 flue-cured tobacco leaves from Yunnan Province, providing references for the cigarette blending and production of high-quality tobacco with characteristics.
基金The authors are grateful for the financial supports from the National Natural Science Foundation of China(50702020,81171461)the Natural Science Foundation of Hunan Province,China(2017JJ2040)the Young Teacher Promotion Fund by Hunan University,China,the Fundamental Research Funds of the Central Universities,China.
文摘Molybdenum disulfide(MoS2)was loaded on biocarbon using waste camellia dregs(CDs)as the carbon source,which was further coated with dopamine hydrochloride to construct biocarbon/MoS2 electrode composites.The electrochemical lithium storage performance of the composites with different MoS2 contents was investigated.SEM results demonstrated that the composite had a three-dimensional foam-like structure with MoS2 as the interlayer.XRD and HRTEM tests revealed that MoS2 interlayer spacing in the composite was expanded.XPS analysis showed that new Mo—N bonds were formed in the active material.The electrochemical tests showed that the composite with a MoS2 content of 63%had a high initial specific capacity of 1434 mA·h/g at a current density of 100 mA/g.After a long cycle at a high current,it also showed good cycling stability and the capacity retention was nearly 100%.In addition,it had good lithium ion deintercalation ability in the electrochemical kinetics test.
