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Corrosive electrochemistry of jamesonite by cyclic voltammetry 被引量:1
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作者 余润兰 胡岳华 +1 位作者 邱冠周 覃文庆 《Journal of Central South University of Technology》 2004年第3期286-290,共5页
The corrosive electrochemistry of jamesonite was studied by cyclic voltammetry. Every peak in voltammograms was identified through thermodynamic calculation. The results show an irreversible electrode process by the s... The corrosive electrochemistry of jamesonite was studied by cyclic voltammetry. Every peak in voltammograms was identified through thermodynamic calculation. The results show an irreversible electrode process by the strong adsorption of oxidation elemental sulfur on jamesonite. A deficient-metal and sulfur-rich compound is formed under the potential of 80 mV at pH 6.86. The passive action by elemental sulfur occurs from 80 to 470 mV and S2O2-3, SO2-4 are produced at potential over 470 mV. The anodic peak producing SO2-4 is inhibited due to the deposition of PbSO4 at higher potential in Na2SO4 solution. The corrosive action of jamesonite becomes strong and the redox characterization similar to PbS, FeS and Sb2S3 appears at pH 9.18. 展开更多
关键词 JAMESONITE corrosive electrochemistry VOLTAMMETRY
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Construction of AgVO_(3)/ZIF-8 composites for enhanced degradation of tetracycline 被引量:1
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作者 ZHU Min WANG Yuxin +7 位作者 LI Xiao XU Yaxu ZHU Junwen WANG Zihao ZHU Yu HUANG Xiaochen XU Dan Abul Monsur Showkot Hossaine 《无机化学学报》 北大核心 2025年第5期994-1006,共13页
AgVO_(3)/ZIF-8 composites with enhanced photocatalytic effect were prepared by the combination of AgVO_(3)and ZIF-8.X-ray diffraction(XRD),scanning electron microscopy(SEM),high-power transmission electron microscopy(... AgVO_(3)/ZIF-8 composites with enhanced photocatalytic effect were prepared by the combination of AgVO_(3)and ZIF-8.X-ray diffraction(XRD),scanning electron microscopy(SEM),high-power transmission electron microscopy(HRTEM),X-ray photoelectron spectroscopy(XPS),ultraviolet-visible diffuse reflectance spectroscopy(UV-Vis DRS),photoluminescence(PL)spectroscopy,electron spin resonance(ESR)spectroscopy,transient photocurrent and electrochemical impedance spectroscopy(EIS)were used to characterize binary composites.Tetracycline(TC)was used as a substrate to study the performance efficiency of the degradation of photocatalysts under light conditions,and the degradation effect of TC was also evaluated under different mass concentrations and ionic contents.In addition,we further investigated the photocatalytic mechanism of the binary composite material AgVO_(3)/ZIF-8 and identified the key active components responsible for the catalytic degradation of this new photocatalyst.The experimental results show that the degradation efficiency of 10%-AZ,prepared with a molar ratio of 10%AgVO_(3)and ZIF-8 to TC,was 75.0%.This indicates that the photocatalytic activity can be maintained even under a certain ionic content,making it a suitable photocatalyst for optimal use.In addition,the photocatalytic mechanism of binary composites was further studied by the active species trapping experiment. 展开更多
关键词 AgVO_(3) ZIF‑8 metal‑organic framework PHOTOCATALYSIS TETRACYCLINE
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Synergistic effect of nitrocellulose coating on structural and reactivity stabilization of ammonium nitrate oxidizer 被引量:1
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作者 Amir Abdelaziz Djalal Trache +5 位作者 Ahmed Fouzi Tarchoun Hani Boukeciat Yash Pal Sourbh Thakur Weiqiang Pang Thomas M.Klapötke 《Defence Technology(防务技术)》 2025年第1期35-43,共9页
The present work aims to stabilize the room temperature allotropic transition of ammonium nitrate(AN)particles utilizing a microencapsulation technique,which involves solvent/non-solvent in which nitrocellulose(NC)has... The present work aims to stabilize the room temperature allotropic transition of ammonium nitrate(AN)particles utilizing a microencapsulation technique,which involves solvent/non-solvent in which nitrocellulose(NC)has been employed as a coating agent.The SEM micrographs revealed distinct features of both pure AN and NC,contrasting with the irregular granular surface topography of the coated AN particles,demonstrating the adherence of NC on the AN surface.Structural analysis via infrared spectroscopy(IR)demonstrated a successful association of AN and NC,with slight shifts observed in IR bands indicating interfacial interactions.Powder X-ray Diffraction(PXRD)analysis further elucidated the structural changes induced by the coating process,revealing that the NC coating altered the crystallization pattern of its pure form.Thermal analysis demonstrates distinct profiles for pure and coated AN,for which the coated sample exhibits a temperature increase and an enthalpy decrease of the room temperature allotropic transition by 6℃,and 36%,respectively.Furthermore,the presence of NC coating alters the intermolecular forces within the composite system,leading to a reduction in melting enthalpy of coated AN by~39%compared to pure AN.The thermal decomposition analysis shows a two-step thermolysis process for coated AN,with a significant increase in the released heat by about 78%accompanied by an increase in the activation barrier of NC and AN thermolysis,demonstrating a stabilized reactivity of the AN-NC particles.These findings highlight the synergistic effect of NC coating on AN particles,which contributed to a structural and reactive stabilization of both AN and NC,proving the potential application of NC-coated AN as a strategically advantageous oxidizer in composite solid propellant formulations. 展开更多
关键词 Ammonium nitrate NITROCELLULOSE STABILIZATION COATING Thermolysis kinetics
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A self-calibrating fluorescent probe for the selective detection and bioimaging of HClO
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作者 GAO Wei SONG Meiqi +4 位作者 REN Xuan BAI Jianliang SU Jing MA Jianlong WANG Zhijun 《无机化学学报》 北大核心 2025年第6期1173-1182,共10页
In this study,a self-calibrating near-infrared fluorescence probe was designed and synthesized based on the dual-fluorophore strategy utilizing methylene blue and coumarin.The probe utilized methylene blue(emission sp... In this study,a self-calibrating near-infrared fluorescence probe was designed and synthesized based on the dual-fluorophore strategy utilizing methylene blue and coumarin.The probe utilized methylene blue(emission spectrum range:640-740 nm)and coumarin fluorophore(emission spectrum range:440-600 nm)as signal output units,thereby achieving effective spectral separation and highly selective detection of HClO.Under physiological pH conditions,HClO triggers an oxidation-cleavage reaction,releasing methylene blue and coumarin,which emit distinct red and green fluorescence,respectively.This dual-emission feature enabled rapid HClO detection with two-channel detection limits of 25.13 nmol·L^(-1)(green channel)and 31.55 nmol·L^(-1)(red channel).Furthermore,in cell imaging experiments,this probe demonstrated excellent cell membrane permeability and low cytotoxicity,successfully enabling the monitoring of both endogenous and exogenous HClO in living cells.By incorporating a twochannel self-calibration system,the probe effectively mitigated signal variations caused by instrumental or environmental interference,substantially improving detection sensitivity and reliability. 展开更多
关键词 fluorescent probe fluorescent crosstalk self-calibrated hypochloric acid dual channel
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The low-temperature deposition of a zincophilic carbon layer on the Zn foil for long-life zinc metal batteries
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作者 LI Chun-yu ZHANG Ming-hui +2 位作者 LANG Xin-yue CHEN Ye DONG Yan-feng 《新型炭材料(中英文)》 北大核心 2025年第1期178-187,共10页
Aqueous zinc metal batteries(ZMBs)which are environmentally benign and cheap can be used for grid-scale energy storage,but have a short cycling life mainly due to the poor reversibility of zinc metal anodes in mild aq... Aqueous zinc metal batteries(ZMBs)which are environmentally benign and cheap can be used for grid-scale energy storage,but have a short cycling life mainly due to the poor reversibility of zinc metal anodes in mild aqueous electrolytes.A zincophilic carbon(ZC)layer was deposited on a Zn metal foil at 450°C by the up-stream pyrolysis of a hydrogen-bonded supramolecular substance framework,as-sembled from melamine(ME)and cyanuric acid(CA).The zincophilic groups(C=O and C=N)in the ZC layer guide uniform zinc plating/stripping and eliminate dendrites and side reactions.so that assembled symmetrical batteries(ZC@Zn//ZC@Zn)have a long-term service life of 2500 h at 1 mA cm^(−2) and 1 mAh cm^(−2),which is much longer than that of bare Zn anodes(180 h).In addition,ZC@Zn//V2O5 full batteries have a higher capacity of 174 mAh g^(−1) after 1200 cycles at 2 A g^(−1) than a Zn//V_(2)O_(5) counterpart(100 mAh g^(−1)).The strategy developed for the low-temperat-ure deposition of the ZC layer is a new way to construct advanced zinc metal anodes for ZMBs. 展开更多
关键词 Aqueous zinc metal batteries Zinc metal anodes Low-temperature deposition Zincophilic carbon layer High performance
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Structure variation of cadmium naphthalene⁃diphosphonates with the changing rigidity of N⁃donor auxiliary ligands
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作者 XU Yan LI Suzhi +3 位作者 LI Yan FENG Lushun SUN Wentao LI Xinxing 《无机化学学报》 北大核心 2025年第2期395-406,共12页
Five cadmium naphthalene-diphosphonates,formulated as[Cd_(1.5)(1,4-ndpaH_(2))2(4,4'-bpyH)(4,4'-bpy)0.5(H_(2)O)_(2)]2(1),[Cd(1,4-ndpaH_(2))(1,4-bib)0.5(H_(2)O)](2),[Cd(1,4-ndpaH3)2(1,2-dpe)(H_(2)O)]·(1,2-d... Five cadmium naphthalene-diphosphonates,formulated as[Cd_(1.5)(1,4-ndpaH_(2))2(4,4'-bpyH)(4,4'-bpy)0.5(H_(2)O)_(2)]2(1),[Cd(1,4-ndpaH_(2))(1,4-bib)0.5(H_(2)O)](2),[Cd(1,4-ndpaH3)2(1,2-dpe)(H_(2)O)]·(1,2-dpe)·7H_(2)O(3),(1,2-bixH)[Cd3(1,4-ndpaH)(1,4-ndpaH_(2))2(H_(2)O)_(2)](4),and[Cd(1,4-ndpaH_(2))(H_(2)O)]·H_(2)O(5),have been synthesized from the selfassembly reactions of 1,4-naphthalenediphosphonic acid(1,4-ndpaH4)with Cd(NO3)2·4H_(2)O by introducing auxiliary ligands with variation of rigidity,such as 4,4'-bipyridine(4,4'-bpy),1,4-bis(1-imidazolyl)benzene(1,4-bib),1,2-di(4-pyridyl)ethylene(1,2-dpe),1,3-di(4-pyridyl)propane(1,3-dpp),and bis(imidazol-1-ylmethyl)benzene(1,2-bix),respectively.Structure resolution by single-crystal X-ray diffraction reveals that compound 1 possesses a layered framework,in which the{Cd3(PO2)2}trimers made up of corner-sharing two{CdO4N2}and one{CdO6}octahedra are connected by phosphonate groups,forming a ribbon,which are cross-linked by 4,4'-bipy ligands,forming a 2D layer.Compound 2 shows a 3D open-framework structure,where chains of corner-sharing{CdO4N}trigonal bipyramids and{PO3C}tetrahedra are cross-linked by 1,4-bib and/or phosphonate groups.A 1D ladder-like chain structure is found in compound 3,where the ladder-like chains made up of corner-sharing{CdO5N}octahedra and{PO3C}tetra hedra are connected by 1,4-ndpaH_(2)^(2-).Both compounds 4 and 5 obtained by the introduction of flexible ligands during the synthesis show a 2D layered structure,which is formed by ligand crosslinking double metal chains.Interestingly,In 4,flexible 1,2-bix was singly protonated,as guest molecules,filled between layer and layer,while flexible ligand 1,3-dpp is absent in 5.Photophysical measurements indicate that compounds 1-5 show ligand-centered emissions. 展开更多
关键词 naphthalene diphosphate N-donor auxiliary ligands crystal structure RIGIDITY flexibility
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Design,synthesis,and detection of Al^(3+)of two zinc complexes based on Schiff base ligands
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作者 YANG Yuanyu XUE Jianhua +3 位作者 BAI Yujia CUI Lulu YANG Dongdong MA Qi 《无机化学学报》 北大核心 2025年第6期1207-1216,共10页
Two new complexes,[Zn_(2)(L1)(HL1)(NO_(3))]·CH_(3)OH(1)and[Zn_(3)(L2)(L3)_(3)Cl]·CH_(3)OH(2),were successfully synthesized by‘one-pot’method based on cinnoline-3-ylhydrazine ligand and zinc with 2-hydroxy-... Two new complexes,[Zn_(2)(L1)(HL1)(NO_(3))]·CH_(3)OH(1)and[Zn_(3)(L2)(L3)_(3)Cl]·CH_(3)OH(2),were successfully synthesized by‘one-pot’method based on cinnoline-3-ylhydrazine ligand and zinc with 2-hydroxy-4-methoxybenzaldehyde and 2-hydroxy-3-methoxybenzaldehyde ligands,respectively,where H_(2)L1=5-methoxy-2-(phthalazin-1-ylhydrazonomethyl)-phenol,H_(2)L2=2-methoxy-6-(phthalazin-1-yl-hydrazonomethyl)-phenol,HL3=2-(1,8-dihydro-[1,2,4]triazolo[3,4-α]phthalazin-3-yl)-6-methoxy-phenol.Complexes 1 and 2 were characterized by infrared spectroscopy,elemental analysis,single-crystal X-ray diffraction,powder X-ray diffraction,etc.It is worth noting that the cinnolin-3-yl-hydrazine ligand and 2-hydroxy-3-methoxybenzaldehyde form two types of Schiff bases(H_(2)L2 and HL3)when in situ reacting and coordinating with Zn(Ⅱ),and HL3 also has two coordination modes.In addition,the fluorescence performance showed that complex 1 can achieve selective and sensitive sensing of Al^(3+)in water with a detection limit of 6.37μmol·L^(-1).CCDC:2413978,1;2413979,2. 展开更多
关键词 Zn-complex Schiff base FLUORESCENCE Al^(3+)detection
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Improving the catalytic performance of TiO_(2) by its surface deposition on CNT buckypapers for use in the removal of wastewater pollutants
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作者 Mariafrancesca Baratta Aleksey Vladimirovich Nezhdanov +6 位作者 Aleksey Valentinovich Ershov Donatella Aiello Anna Napoli Leonardo Di Donna Alexandr Ivanovic Mashin Fiore Pasquale Nicoletta Giovanni De Filpo 《新型炭材料(中英文)》 北大核心 2025年第2期456-481,共26页
Buckypapers(BPs)consist of carbon nanotube(CNT)membranes with good mechanical,thermal and elec-trical properties.We report the modification of CNT buckypapers by the surface deposition of a thin layer of ti-tanium dio... Buckypapers(BPs)consist of carbon nanotube(CNT)membranes with good mechanical,thermal and elec-trical properties.We report the modification of CNT buckypapers by the surface deposition of a thin layer of ti-tanium dioxide and their subsequent photocatalytic use for the removal of three wastewater pollutants:diclofenac(DF),carbofuran(CB)and methylene blue(MB).The results show the following decreases(RE)in the initial concentrations of these pollutants,REDF=99.5%,REMB=96%and RECB=90%after 90 min of exposure to UV-Vis radiation using~0.6 mg of photocatalyst.Experiments also showed that the degradation rate of diclofenac(k=0.1028 min^(−1))is respectively 3.5 and 6 times faster than the values for CB(k=0.0298 min^(−1))and MB(k=0.0174 min^(−1)),probably due to the easier bond cleavage in DF.UV-Vis irradiated solutions of these pollutants were then analyzed by mass spectrometry to identify the species formed during photocatalysis and suggest possible degradation paths for MB,DF,and CB.Data showed that the degradation of DF involves the formation of a photocyclization product through loss of HCl molecule,clearly consuming less energy than that needed for the opening of the central aromatic ring in MB,or the loss of the N-methyl amide functional group for CB. 展开更多
关键词 Carbon nanotubes Buckypapers NANOMATERIALS Water pollutants Titanium dioxide
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PM IRRAS Studies of Organized Molecular Films at a Gold Electrode Surface
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作者 Zhang-Fei Su Ai-Cheng Chen Jacek Lipkowski 《电化学(中英文)》 北大核心 2025年第6期1-18,共18页
This feature article illustrates the potential of polarization modulation infrared reflection absorption spectroscopy(PM IRRAS)to provide molecular-level information about the structure,orientation and conformation of... This feature article illustrates the potential of polarization modulation infrared reflection absorption spectroscopy(PM IRRAS)to provide molecular-level information about the structure,orientation and conformation of constituents of thin films at electrode surfaces.PM IRRAS relies on the surface selection rules stating that the p-polarized IR beam is enhanced,while the s-polarized beam is attenuated at the metal surface.The difference between p-and s-polarized beams eliminates the background of the solvent and provides IR spectra at a single electrode potential.In contrast,two other popular in situ IR spectroscopic techniques,namely,subtractively normalized interfacial Fourier transform infrared spectroscopy(SNIFTIRS)and surface-enhanced infrared reflection absorption spectroscopy(SEIRAS),provide potential difference spectra to remove the signal from the bulk solution.In this feature article,we provide a brief tutorial on how to run the PM IRRAS experiment and describe the methods used for background elimination first.The application of the PM IRRAS in the biomimetic research is then illustrated by three examples:construction of a tethered bilayer,reconstitution of colicin into a phospholipid bilayer and determination of the orientation of nucleolipids in a monolayer assembled at a gold electrode surface.Finally,the structural changes of graphene oxide during its electrochemical reduction are described to highlight the promising application of PM IRRAS in materials science. 展开更多
关键词 Polarization modulation infrared reflection absorption spectroscopy Biomimetic membranes Graphene oxide reduction
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Variation of Membrane Electrode Assembly Catalyst Layer in Unitized Regenerative Fuel Cell
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作者 Yollanda Nurcholifah Dedi Rohendi +4 位作者 Edy Herianto Majlan Nirwan Syarif Addy Rachmat Dwi Hawa Yulianti Nyimas Febrika S 《电化学(中英文)》 北大核心 2025年第4期32-43,共12页
A unitized regenerative fuel cell(URFC)is a device that may function reversibly as either a fuel cell(FC)or water elec-trolysis(WE).An important component of this device is the Membrane electrode assembly(MEA).Therefo... A unitized regenerative fuel cell(URFC)is a device that may function reversibly as either a fuel cell(FC)or water elec-trolysis(WE).An important component of this device is the Membrane electrode assembly(MEA).Therefore,this study aimed to compare the performance outcomes of MEA using electrodes with single and three catalyst layers.This study measured Electrochemical Surface Area(ECSA),Electrochemical Impedance Spectroscopy(EIS),X-ray Diffraction analysis(XRD),and X-ray Fluorescence(XRF).Furthermore,the round-trip efficiency(RTE)of the MEA,as w ell as the performance in FC and WE mode,was measured.In comparison,The ECSA values of Pt-Ru/C and Pt/C with three catalyst layers were higher than the single catalyst layer.This result was supported by electrode characterization data for XRD and XRF.The respective electrical conductivity values of Pt-Ru/C and Pt/C with three catalyst layers are also higher than the single cata-lyst layer,and the performance of URFC using MEA with three catalyst layers has the highest value of RTE among the MEA performances of URFC,which is 100%at a current density of 4 mA·cm-2. 展开更多
关键词 Unitized regenerative fuel cell Round trip efficiency Pt-Ru/C Membrane electrode assembly Electrochemical surface area
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Recent progress on the use of lignin-based porous carbon in supercapacitors
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作者 ZHA Ding-chen WANG Jia-heng +6 位作者 Hao Rui-xiang Wu Yun-feng LI Xiu-he ZHAO Jia-wen LI Wen PIAO Wen-xiang JIANG Nan-zhe 《新型炭材料(中英文)》 北大核心 2025年第1期50-80,共31页
With the development of electronics and portable devices,there is a significant drive to develop electrode materials for supercapacitors that are lightweight,economical,and provide high energy and power densities.Lign... With the development of electronics and portable devices,there is a significant drive to develop electrode materials for supercapacitors that are lightweight,economical,and provide high energy and power densities.Lignin-based porous carbons have recently been extensively studied for en-ergy storage applications because of their characteristics of large specific surface area,easy doping,and high conductivity.Significant progress in the synthesis of porous carbons derived from lignin,using different strategies for their preparation and modification with heteroatoms,metal oxides,met-al sulfides,and conductive polymers is considered and their electrochemical performances and ion storage mechanisms are discussed.Considerable fo-cus is directed towards the challenges encountered in using lignin-based por-ous carbons and the ways to optimize specific capacity and energy density for supercapacitor applications.Finally,the limitations of existing technolo-gies and research directions for improving the performance of lignin-based carbons are discussed. 展开更多
关键词 LIGNIN Porous carbon SUPERCAPACITOR CARBONIZATION
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Insights into the anisotropy in hydroxamic acid adsorption on different exposed crystal surfaces of malachite from first-principle calculations
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作者 ZHANG Chen-yang LIU Si-yuan +6 位作者 JIANG Wan-yao ZHANG Hong-liang WU Lin-lin RAO Xin SUN Wei ZOU You PEI Yong 《Journal of Central South University》 2025年第7期2446-2462,共17页
The intricate grinding process exposes various cleavage surfaces of mineral particles.This paper systematically investigates the structural characteristics of exposed malachite crystal surfaces and the adsorption beha... The intricate grinding process exposes various cleavage surfaces of mineral particles.This paper systematically investigates the structural characteristics of exposed malachite crystal surfaces and the adsorption behavior and mechanism of hydroxamic acid and water molecules using first-principle density functional theory.The study reveals anisotropic surface energies among crystal surfaces,ranked as(201)>(100)>(110)>(001)>(010)>(201).The adsorption of hydroxamic acid and water molecules on malachite surfaces also exhibited anisotropy.The difference in adsorption strength between hydroxamic acid and water molecules on the six exposed surfaces followed the order of(110)>(100)>(010)>(001)>(201)>(201),and the resistance of water molecules to the adsorption of hydroxamic acid on the six exposed surfaces was(110)>(201)>(010)>(201)>(001)>(100).It indicates that the reagent exhibits a strong competitive advantage in adsorption on the(100)surface,and the hindrance of water molecules to reagent adsorption is relatively small,which is favorable for flotation.This study provides theoretical references and innovative insights for the precise design of flotation reagents,as well as for the meticulous optimization of mineral surface interfaces,with the objective of enhancing flotation separation. 展开更多
关键词 MALACHITE flotation reagents ADSORPTION surface density functional theory(DFT)
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Impacts of climate change on cotton production and advancements in genomic approaches for stress resilience enhancement
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作者 KHAN Muhammad Aamir ANWAR Saeed +5 位作者 ABBAS Mubashir ANEEQ Muhammad DE JONG Fokke AYAZ Muhammad WEI Yunxiao ZHANG Rui 《Journal of Cotton Research》 2025年第2期270-289,共20页
Cotton is an essential agricultural commodity,but its global yield is greatly affected by climate change,which poses a serious threat to the agriculture sector.This review aims to provide an overview of the impact of ... Cotton is an essential agricultural commodity,but its global yield is greatly affected by climate change,which poses a serious threat to the agriculture sector.This review aims to provide an overview of the impact of climate change on cotton production and the use of genomic approaches to increase stress tolerance in cotton.This paper discusses the effects of rising temperatures,changing precipitation patterns,and extreme weather events on cotton yield.It then explores various genomic strategies,such as genomic selection and marker-assisted selection,which can be used to develop stress-tolerant cotton varieties.The review emphasizes the need for interdisciplinary research efforts and policy interventions to mitigate the adverse effects of climate change on cotton production.Furthermore,this paper presents advanced prospects,including genomic selection,gene editing,multi-omics integration,highthroughput phenotyping,genomic data sharing,climate-informed breeding,and phenomics-assisted genomic selection,for enhancing stress resilience in cotton.Those innovative approaches can assist cotton researchers and breeders in developing highly resilient cotton varieties capable of withstanding the challenges posed by climate change,ensuring the sustainable and prosperous future of cotton production. 展开更多
关键词 COTTON Climate Change Stress tolerance Genomic selection Gene editing QTLS Fiber
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Preparation of high dispersion and high performance PtRu/CNTs catalyst by an organic colloid method 被引量:4
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作者 王宁卡特 刘军民 +1 位作者 廖世军 V.Birss 《电池》 CAS CSCD 北大核心 2006年第5期371-374,共4页
关键词 PtRu/CNTs organic COLLOIDAL METHOD direct METHANOL fuel cell(DMFC)
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Recent advances in catalytic combustion of AP-based composite solid propellants 被引量:22
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作者 Narendra Yadav Prem Kumar Srivastava Mohan Varma 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2021年第3期1013-1031,共19页
Composite solid propellants(CSPs) have widely been used as main energy source for propelling the rockets in both space and military applications. Internal ballistic parameters of rockets like characteristic exhaust ve... Composite solid propellants(CSPs) have widely been used as main energy source for propelling the rockets in both space and military applications. Internal ballistic parameters of rockets like characteristic exhaust velocity, specific impulse, thrust, burning rate etc., are measured to assess and control the performance of rocket motors. The burn rate of solid propellants has been considered as most vital parameter for design of solid rocket motors to meet specific mission requirements. The burning rate of solid propellants can be tailored by using different constituents, extent of oxidizer loading and its particle size and more commonly by incorporating suitable combustion catalysts. Various metal oxides(MOs),complexes, metal powders and metal alloys have shown positive catalytic behaviour during the combustion of CSPs. These are usually solid-state catalysts that play multiple roles in combustion of CSPs such as reduction in activation energy, enhancement of rate of reaction, modification of sequences in reaction-phase, influence on condensed-phase combustion and participation in combustion process in gas-phase reactions. The application of nanoscale catalysts in CSPs has increased considerably in recent past due to their superior catalytic properties as compared to their bulk-sized counterparts. A large surface-to-volume ratio and quantum size effect of nanocatalysts are considered to be plausible reasons for improving the combustion characteristics of propellants. Several efforts have been made to produce nanoscale combustion catalysts for advanced propellant formulations to improve their energetics. The work done so far is largely scattered. In this review, an effort has been made to introduce various combustion catalysts having at least a metallic entity. Recent developments of nanoscale combustion catalysts with their specific merits are discussed. The combustion chemistry of a typical CSP is briefly discussed for providing a better understanding on role of combustion catalysts in burning rate enhancement. Available information on different types of combustion nanocatalysts is also presented with critical comments. 展开更多
关键词 Composite solid propellants Burn rate modifier Metallic nano-catalysts Catalytic combustion Thermal decomposition
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Use of Atomic Absorption Spectrometry in Assessment of Biomonitor Plants for Lead,Cadmium and Copper Pollution 被引量:9
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作者 Gokce Kaya Mehmet Yaman 《光谱学与光谱分析》 SCIE EI CAS CSCD 北大核心 2012年第1期229-234,共6页
Eleven plant species were collected from the vicinity of lead-battery plant in the city of Gaziantep,Turkey.Lead,cadmium and copper concentrations in the soil and leaves of plants were determined by atomic absorption ... Eleven plant species were collected from the vicinity of lead-battery plant in the city of Gaziantep,Turkey.Lead,cadmium and copper concentrations in the soil and leaves of plants were determined by atomic absorption spectrometry.Lead,Cd and Cu concentrations in the soil samples taken from battery area were found to be in the ranges of 304~602,0.4~0.44 and 31~37 mg·kg-1,respectively.Significantly increased lead concentration up to 2 750 mg·kg-1 was found in the leaves of Eleagnus angustifolia L.plant.The lead concentrations in the other plant leaves taken from 50 m around battery factory followed the order Ailanthus altissima>Morus sp.>Juglans regia L.>Ficus carica L.>Cydonia oblonga Miller>Prunus x domestica L.The plants,Populus nigra L.,Eleagnus angustifolia L.and Salix sp.were found useful for Cd,and the plant,Eleagnus angustifolia L.for Pb,to be considered as potential biomonitor.Especially,leaves of trees and plants taken from the distance of 50 m from battery plant have relatively higher Pb concentrations.Therefore,people who and animals which live in this area and benefit from these soil and plants have vital risks. 展开更多
关键词 ATOMIC absorption LEAD CADMIUM Coper BIOMONITOR PLANTS POLLUTION
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Comparative analysis of chemical components between barks and leaves of Eucommia ulmoides Oliver 被引量:10
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作者 周菊峰 张泰铭 +1 位作者 陈望爱 梁逸曾 《Journal of Central South University》 SCIE EI CAS 2009年第3期371-379,共9页
The chemical components of the essential oils in the barks and leaves of Eucommia ulmoides Oliver were analyzed and compared by chromatograms and mass spectra technique, heuristic evolving latent projections (HELP), a... The chemical components of the essential oils in the barks and leaves of Eucommia ulmoides Oliver were analyzed and compared by chromatograms and mass spectra technique, heuristic evolving latent projections (HELP), alternative moving window factor analysis (AMWFA) algorithms and normalization method based on the peak areas; the flavones in the barks and leaves of Eucommia ulmoides Oliver were separated on an ODS column by gradient elution carried out with the flow phase consisting of water, methanol and phosphoric acid (0.1%), and their contents were quantitatively determined by standard curve method and diode array detection (DAD) at 362 nm. The results show that 68 and 73 compounds respectively from essential oils of the barks and leaves of Eucommia ulmoides Oliver are identified, and there are 33 mutual compounds among 108 compounds determined. The total contents of these volatile components of the two samples possess 92.9% and 97.75% of the gross of the relevant essential oils, respectively; the contents of the rutin, quercetin and kaempferol in the barks and leaves of Eucommia ulmoides Oliver are 0.016 9, 0.003 6, 0.002 1 and 0.064 4, 0.030 2, 0.010 0 mg/g, respectively, and the determination recoveries are 95.2%-106.2%. The comparative analysis shows that for the barks and leaves of Eucommia ulmoides Oliver, there are significant differences in their components of the relevant essential oils and flavones. 展开更多
关键词 couple chromatography chemometric algorithm comparative analysis essential oil FLAVONE Eucommia ulmoides Oliver
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Adsorption Behavior and Inhibition Corrosion Effect of Sodium Carboxymethyl Cellulose on Mild Steel in Acidic Medium 被引量:8
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作者 BAYOL E. GüRTEN A.A. DURSUN M. KAYAKIRILMAZ K. 《物理化学学报》 SCIE CAS CSCD 北大核心 2008年第12期2236-2242,共7页
The effect of sodium carboxymethyl cellulose (Na-CMC) on the corrosion behavior of mild steel in 1.0 mol·L-1 HCl solution has been investigated by using weight loss (WL) measurement, potentiodynamic polarization,... The effect of sodium carboxymethyl cellulose (Na-CMC) on the corrosion behavior of mild steel in 1.0 mol·L-1 HCl solution has been investigated by using weight loss (WL) measurement, potentiodynamic polarization, linear polarization resistance (LPR), and electrochemical impedance spectroscopy (EIS) methods. These results showed that the inhibition efficiency of Na-CMC increased with increasing the inhibitor concentration. Potentiodynamic polarization studies revealed that the Na-CMC was a mixed type inhibitor in 1.0 mol·L-1 HCl. The adsorption of the inhibitor on mild steel surface has been found to obey the Langmuir isotherm. The effect of temperature on the corrosion behavior of mild steel in 1.0 mol·L-1 HCl with addition of 0.04% of Na-CMC has been studied in the temperature range of 298-328 K. The associated apparent activation energy (E*a ) of corrosion reaction has been determined. Scanning electron microscopy (SEM) has been applied to investigate the surface morphology of mild steel in the absence and presence of the inhibitor molecules. 展开更多
关键词 吸附行为 抑制作用 腐蚀作用 羧甲基纤维素钠 低碳钢 酸性介质
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Determination of contents of eight alkaloids in fruits of Macleaya cordata (Willd) R. Br. from different habitats and antioxidant activities of extracts 被引量:9
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作者 钟明 黄可龙 +2 位作者 曾建国 黎霜 张丽 《Journal of Central South University》 SCIE EI CAS 2010年第3期472-479,共8页
A reliable ultrasound-assisted extraction (UAE) method combined with HPLC-UV for quantification of eight active alkaloids in fruits of Macleaya cordata (Willd) R. Br. was developed. The optimization conditions of ... A reliable ultrasound-assisted extraction (UAE) method combined with HPLC-UV for quantification of eight active alkaloids in fruits of Macleaya cordata (Willd) R. Br. was developed. The optimization conditions of UAE were obtained by using Box-Behnken design of response surface methodology. Chromatography was carried out using a Kromasil C18 column by gradient elution with 0.1% phosphoric acid aqueous solution for HPLC-UV. All calibration curves showed good linear correlation coefficients (R^2〉0.999 6) and recoveries (from 97.3% to 104.9%) were acceptable. 1,1-diphenyl-2-picrylhydrazyl (DPPH) method was employed to test the antioxidant activity of the extract from the samples. The proposed method was successfully applied to quantifying eight components in nine samples of M.cordata, and significant variations of alkaloid contents and antioxidant aetivity of the samples from different habitats were demonstrated. It presents a powerful proof for the selection of the best sources to extract eight kinds of alkaloids. 展开更多
关键词 Macleaya cordata (Willd) R. Br. ALKALOID ultrasound-assisted extraction antioxidant activity HPLC-UV response surface methodology
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The catalytic activity of transition metal oxide nanoparticles on thermal decomposition of ammonium perchlorate 被引量:6
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作者 Jalpa A. Vara Pragnesh N. Dave Shalini Chaturvedi 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2019年第4期629-635,共7页
The catalytic proficiency of three MONs for AP thermal decomposition was studied in this work.A chemical co-precipitation method was used for synthesis of MONs(CuZnO,CoZnO,and NiZnO)and their characterization carried ... The catalytic proficiency of three MONs for AP thermal decomposition was studied in this work.A chemical co-precipitation method was used for synthesis of MONs(CuZnO,CoZnO,and NiZnO)and their characterization carried out by utilizing XRD,FTIR,and SEM.The TGA/DSC technique was employed for the investigation of the catalytic proficiency of MONs on the AP.The DSC data were used for measuring activation energy of catalyzed AP by using Ozawa,Kissinger,and Starink method.The MONs were much sensitive for AP decomposition,and the performance of AP decomposition was further improved.Among all the MONs,the CuZnO exhibits higher catalytic action than others and decomposition temperature of AP is descending around 117℃ by CuZnO.The reduction in the activation energy was noticed after the incorporation of MONs in AP. 展开更多
关键词 Metal OXIDE nanoparticles(MONs) AMMONIUM perchlorate(AP) CATALYTIC activity Activation energy
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