Heterointerface Engineering-Induced Oxygen Defects for the Manganese Dissolution Inhibition in Aqueous Zinc Ion Batteries

Manganese-based material is a prospective cathode material for aqueous zinc ion batteries(ZIBs)by virtue of its high theoretical capacity,high operating voltage,and low price.However,the manganese dissolution during the electrochemical reaction causes its electrochemical cycling stability to be undesirable.In this work,heterointerface engineering-induced oxygen defects are introduced into heterostructure MnO_(2)(δa-MnO_(2))by in situ electrochemical activation to inhibit manganese dissolution for aqueous zinc ion batteries.Meanwhile,the heterointerface between the disordered amorphous and the crystalline MnO_(2)ofδa-MnO_(2)is decisive for the formation of oxygen defects.And the experimental results indicate that the manganese dissolution ofδa-MnO_(2)is considerably inhibited during the charge/discharge cycle.Theoretical analysis indicates that the oxygen defect regulates the electronic and band structure and the Mn-O bonding state of the electrode material,thereby promoting electron transport kinetics as well as inhibiting Mn dissolution.Consequently,the capacity ofδa-MnO_(2)does not degrade after 100 cycles at a current density of 0.5 Ag^(-1)and also 91%capacity retention after 500cycles at 1 Ag^(-1).This study provides a promising insight into the development of high-performance manganese-based cathode materials through a facile and low-cost strategy.

Synergism of preintercalated manganese ions and lattice water in vanadium oxide cathodes for high-capacity and long-life Zn-ion batteries

Aqueous Zn-ion batteries(AZIBs)are recognized as a promising energy storage system with intrinsic safety and low cost,but its applications still rely on the design of high-capacity and stable-cycling cathode materials.In this work,we present an intercalation mechanism-based cathode materials for AZIB,i.e.the vanadium oxide with pre-intercalated manganese ions and lattice water(noted as MVOH).The synergistic effect between Mn^(2+)and lattice H_(2)O not only expands the interlayer spacing,but also significantly enhances the structural stability.Systematic in-situ and ex-situ characterizations clarify the Zn^(2+)/H^(+)co–(de)intercalation mechanism of MVOH in aqueous electrolyte.The demonstrated remarkable structure stability,excellent kinetic behaviors and ion-storage mechanism together enable the MVOH to demonstrate satisfactory specific capacity of 450 mA h g^(−1)at 0.2 A g^(−1),excellent rate performance of 288.8 mA h g^(−1)at 10 A g^(−1)and long cycle life over 20,000 cycles at 5 A g^(−1).This work provides a practical cathode material,and contributes to the understanding of the ion-intercalation mechanism and structural evolution of the vanadium-based cathode for AZIBs.

Hot deformation behavior and hot-metal-gas-forming process of V micro-alloyed high manganese steel

The hot deformation behavior of a newly designed V micro-alloyed high manganese steel(HMnS)was investigated in order to guide the development of the hot-metal-gas-forming process.Single-pass hot compression experiments were conducted in the temperature range of 950–1100°C and the strain rate range of 0.05–10 s^(−1),and the stress–strain curves and the corresponding softening mechanism of the V micro-alloyed HMnS were analyzed.Results show that two types of stress–strain curves,representing the work hardening(WH)-dynamic recovery(DRV)-dynamic recrystallization(DRX)mechanism and the WH–DRV mechanism,respectively,occur during the deformation process.Moreover,the WH–DRV–DRX mechanism gradually transforms into the WH–DRV mechanism with the increasing strain rate and decreasing deformation temperature.Two types of constitutive models considering the softening mechanism difference were established and verified by additional hot-deformation experiments.Hot processing map of the HMnS was established and correlated well with the microstructure evolution result.Based on the constitutive models and processing map,the optimal processing parameter range and flow stress of HMnS for the hot-metal-gas-forming were determined.

Preparation of Manganese Oxide and Its Adsorption Properties

The in-situ oxidation of manganese sulfate solution with H2O_(2),sodium hypochlorite,potassium permanganate and oxygen as oxidants was investigated by means of SEM,EDS,XRD,BET and infrared analysis,and the effects of different oxidants on the morphology,phase composition,surface properties and specific surface area of manganese oxides were investigated.The experimental results show that the diameter of manganese oxide particles prepared with H_(2)O_(2)is the smallest,about 50 nm,and the specific surface area is the largest,63.8764 m^(2)/g.It has the advantages of abundant surface hydroxyl groups,no introduction of other impurities and large adsorption potential.It is most suitable to be used as an oxidant for oxidizing manganese sulfate solution to prepare manganese oxide by in-situ oxidation.Nano manganese oxide prepard by H_(2)O_(2)in-situ oxidation method is used as adsorbent to adsorb cobalt and nickel impurities in manganese sulfate.When the reaction pH is 6,the reaction time is 30min and the amount of adsorbent is 1.0 g,the adsorption rates of cobalt and nickel impurities in 100ml manganese sulfate solution are 97.59%and 97.67%,respectively.The residual amounts of cobalt and nickel meet the industrial process standard of first-class products(Co,Ni w/%≤0.005)of high-purity manganese sulfate(Hg/t4823-2015)for batteries.The study plays a guiding role in the preparation and regulation of manganese oxide,and provides a new method with high efficiency,purity and adsorbent availability for the preparation of high-purity manganese sulfate solution.

Manganese-Catalyzed Ring-Opening C—C Bond Fluorination of Cyclobutanols

Manganese-catalyzed C—C bond cleavage of cyclobutanols has attracted great attention due to the high abundance and cheap and eco-friendly behaviour.A manganese-catalyzed ring-opening C—C bond fluorination of cyclobutanols is reported.Under mild conditions,the reaction provides a straightforward access to γ-fluorinated ketones using 10 mol% Mn(OAc)_(2) as catalyst and electrophilic fluorination reagent,which was generated in situ from HF·Et 3N and PhIO,as fluorine source.The reaction has an excellent functional-group tolerance and displays a broad substrate scope,affording the corresponding products in 50%~76%yields.

Enhanced recovery of high-purity Fe powder from iron-rich electrolytic manganese residue by slurry electrolysis

Iron-rich electrolytic manganese residue(IREMR)is an industrial waste produced during the processing of electrolytic metal manganese,and it contains certain amounts of Fe and Mn resources and other heavy metals.In this study,the slurry electrolysis technique was used to recover high-purity Fe powder from IREMR.The effects of IREMR and H2SO4 mass ratio,current density,reaction temper-ature,and electrolytic time on the leaching and current efficiencies of Fe were studied.According to the results,high-purity Fe powder can be recovered from the cathode plate,and the slurry electrolyte can be recycled.The leaching efficiency,current efficiency,and purity of Fe reached 92.58%,80.65%,and 98.72wt%,respectively,at a 1:2.5 mass ratio of H2SO4 and IREMR,reaction temperature of 60℃,electric current density of 30 mA/cm^(2),and reaction time of 8 h.In addition,vibrating sample magnetometer(VSM)analysis showed that the coercivity of electrolytic iron powder was 54.5 A/m,which reached the advanced magnetic grade of electrical pure-iron powder(DT4A coercivity standard).The slurry electrolytic method provides fundamental support for the industrial application of Fe resource recovery in IRMER.

The Influence of CO_(2) Cured Manganese Slag on the Performance and Mechanical Properties of Ultra-High Performance Concrete

The presence of toxic elements in manganese slag(MSG)poses a threat to the environment due to potential pollution.Utilizing CO_(2) curing on MS offers a promising approach to immobilize toxic substances within this material,thereby mitigating their release into the natural surroundings.This study investigates the impact of CO_(2) cured MS on various rheological parameters,including slump flow,plastic viscosity(η),and yield shear stress(τ).Additionally,it assesses flexural and compressive strengths(f_(t) and f_(cu)),drying shrinkage rates(DSR),durability indicators(chloride ion migration coefficient(CMC),carbonization depth(CD)),and the leaching behavior of heavy metal elements.Microscopic examination via scanning electron microscopy(SEM)is employed to elucidate the underlying mechanisms.The results indicate that CO_(2) curing significantly enhances the slump flow of ultra-high performance concrete(UHPC)by up to 51.2%.Moreover,it reduces UHPC’sηandτby rates ranging from 0%to 52.7%and 0%to 40.2%,respectively.The DSR exhibits a linear increase corresponding to the mass ratio of CO_(2) cured MS.Furthermore,CO_(2) curing enhances both f_(t) and f_(cu) of UHPC by up to 28.7%and 17.6%,respectively.The electrical resistance is also improved,showing an increase of up to 53.7%.The relationship between mechanical strengths and electrical resistance follows a cubic relationship.The CO_(2) cured MS demonstrates a notable decrease in the CMC and CD by rates ranging from 0%to 52.6%and 0%to 26.1%,respectively.The reductions of leached chromium(Cr)and manganese(Mn)are up to 576.3%and 1312.7%,respectively.Overall,CO_(2) curing also enhances the compactness of UHPC,thereby demonstrating its potential to improve both mechanical and durability properties.

Covalency competition induced selective bond breakage and surface reconstruction in manganese cobaltite towards enhanced electrochemical charge storage

Manganese cobaltite(MnCo_(2)_(4))is a promising electrode material because of its attractive redox chemistry and excellent charge storage capability.Our previous work demonstrated that the octahedrally-coordinated Mn are prone to react with the hydroxyl ions in alkaline electrolyte upon electrochemical cycling and separates on the surface of spinel to reconstruct into d-MnO_(2) nanosheets irreversibly,thus results in a change of the reaction mechanism with Kþion intercalation.However,the low capacity has greatly limited its practical application.Herein,we found that the tetrahedrally-coordinated Co_(2) þions were leached when MnCo_(2)_(4) was equilibrated in 1 mol L^(-1) HCl solution,leading to the formation of layered CoOOH on MnCo_(2)_(4) surface which is originated from the covalency competition induced selective breakage of the CoT–O bond in CoT–O–CoO and subsequent rearrangement of free Co_(6) octahedra.The as-formed CoOOH is stable upon cycling in alkaline electrolyte,exhibits conversion reaction mechanism with facile proton diffusion and is free of massive structural evolution,thus enables utilization of the bulk electrode material and realizes enhanced specific capacity as well as facilitated charge transfer and ion diffusion.In general,our work not only offers a feasible approach to deliberate modification of MnCo_(2)_(4)'s surface structure,but also provides an in-depth understanding of its charge storage mechanism,which enables rational design of the spinel oxides with promising charge storage properties.

共表达分子伴侣蛋白提高III型普鲁兰水解酶在短小芽孢杆菌中的分泌表达及发酵优化

本研究旨在通过共表达分子伴侣蛋白以及优化发酵条件来提高III型普鲁兰水解酶(TK-PUL)在短小芽孢杆菌中的分泌表达水平。通过构建共表达TK-PUL和分子伴侣蛋白的多种重组短小芽孢杆菌,并以胞外酶活为指标对其进行筛选,确定最有利于TK-PUL分泌表达的分子伴侣蛋白及对应的重组短小芽孢杆菌。在此基础上采用单因素实验和响应面法优化重组短小芽孢杆菌的发酵条件。结果表明,共表达分子伴侣蛋白PrsA^(Ba)的重组短小芽孢杆菌的胞外酶活达到98.79 U/mL,提高了0.31倍。该重组短小芽孢杆菌的最佳培养基包括19.65 g/L葡萄糖、21.46 g/L酵母提取物、12.01 g/L MgCl_(2)·6H_(2)O、9.02 g/L脯氨酸、0.01 g/L FeSO4·7H_(2)O、0.01 g/L MnSO4·4H_(2)O、0.001 g/L ZnSO4·7H_(2)O。在发酵温度为35℃、起始发酵pH为7.0的条件下,该重组短小芽孢杆菌于最佳培养基中培养66 h时,其胞外酶活达到192.68 U/mL,提高了1.56倍。本研究通过共表达分子伴侣蛋白和发酵优化实现了TK-PUL在短小芽孢杆菌的高效分泌表达,为TK-PUL的应用提供了基础。

混合牙列期骨性III类错合与骨性I类错合基骨及牙弓对比研究

目的:通过测量混合牙列期骨性III类错合患者与骨性I类错合患者的锥形束计算机断层扫描(Cone beam computed tomography, CBCT),对比分析上下颌牙弓、基骨弓长度与宽度差异及协调性,以期为替牙期骨性III类错合畸形治疗提供参考依据。方法:选择替牙列期骨性III类错合与骨性I类错合各30例,通过Dolphin软件处理收集到的DICOM (Digital Imaging and Communications in Medicine)医学图像数据,行三维重建并测量上下颌牙弓、基骨弓的长度与宽度,计算同一牙段牙弓宽度与基骨弓宽度之间的差值,比较骨性III类与骨性I类错牙合畸形牙弓与基骨弓宽度差值的差异。结果:1) 骨性III类错合组上颌牙弓及基骨弓长度均小于骨性I类错合组,下颌基骨弓长度大于骨性I类错合组,且差异有统计学意义(P 0.05)。2) 骨性III类错合组下颌前段及中段基骨弓宽度大于骨性I类错合组,差异有统计学意义(P 0.05)。3) 骨性III类错合组上颌牙弓与基骨弓宽度的差值均大于骨性I类错合组,下颌牙弓与基骨弓宽度的差值均小于骨性I类错合组,其中上颌后段牙弓宽度与基骨弓宽度差值差异有统计学意义(P < 0.05)。结论:混合牙列期骨性III类错合存在牙弓、基骨弓不调,上颌可扩大基骨弓,下颌可扩大牙弓,以期改善牙弓与基骨弓的协调性。

基于NSGA-III算法求解柔性作业车间调度问题

针对多目标柔性作业车间调度问题,提出一种改进NSGA-Ⅲ算法,以完工时间、机器总负荷、瓶颈机器负荷为目标建立调度模型。首先,为提高种群的多样性,提出一种基于惩罚的边界相交距离定义关联操作中种群个体与参考向量之间的距离;其次,为提高环境选择的计算效率,利用基于惩罚的边界相交距离消除机制来保护个体,降低了个体保护策略的计算成本;最后,为避免种群陷入局部最优,在遗传算子中采用一种改进的变异策略。运用两个评价指标与NSGA-Ⅲ算法进行比较,其收敛性与多样性均由于NSGA-Ⅲ算法。同时在4个Kacem算例上进行测试得出改进NSGA-Ⅲ算法解的质量较高,最后通过实际的生产实例证明改进的NSGA-Ⅲ算法优于或等同于现存在的方法,也证明了该方法在解决多目标柔性作业车间调度难题上的可操作性。

Recent Advances on Challenges and Strategies of Manganese Dioxide Cathodes for Aqueous Zinc-Ion Batteries

Aqueous zinc-ion batteries(AZIBs)are regarded as promising electrochemical energy storage devices owing to its low cost,intrinsic safety,abundant zinc reserves,and ideal specific capacity.Compared with other cathode materials,manganese dioxide with high voltage,environmental protection,and high theoretical specific capacity receives considerable attention.However,the problems of structural instability,manganese dissolution,and poor electrical conductivity make the exploration of high-performance manganese dioxide still a great challenge and impede its practical applications.Besides,zinc storage mechanisms involved are complex and somewhat controversial.To address these issues,tremendous efforts,such as surface engineering,heteroatoms doping,defect engineering,electrolyte modification,and some advanced characterization technologies,have been devoted to improving its electrochemical performance and illustrating zinc storage mechanism.In this review,we particularly focus on the classification of manganese dioxide based on crystal structures,zinc ions storage mechanisms,the existing challenges,and corresponding optimization strategies as well as structure-performance relationship.In the final section,the application perspectives of manganese oxide cathode materials in AZIBs are prospected.

Recent progress of advanced manganese oxide-based materials for acidic oxygen evolution reaction: Fundamentals, performance optimization,and prospects

The oxygen evolution reaction(OER) is the basis of various sustainable energy conversion and storage techniques,especially hydrogen production by water electrolysis.To realize the practical application of hydrogen energy and mass-scale hydrogen production via water electrolysis,several obstacles,such as the multi-electron transfer OER process with sluggish kinetics and overall high reaction barrier,should be overcome.Manganese oxide-based(MnOx) materials,especially MnO_(2),have emerged as promising non-noble electrocatalysts for water electro-oxidation under acidic conditions due to their wellbalanced properties between catalytic activity and stability.This review introduces the fundamental understanding of the catalytic OER process on MnOx-based materials,including the conventional adsorbate evolution mechanism(AEM) and emerging lattice oxygen oxidation mechanism(LOM).The rational screening and prediction of MnOx-based catalysts that can stably catalyze OER in acid are summarized based on Pourbaix diagram analysis and thermodynamic density functional theory(DFT) calculations.Then,the up-to-date progress of upgrading the OER catalytic performance of MnOx-based catalysts by composite construction is reviewed.Afterward,feasible strategies to improve the electrocatalytic activity and lifetime of MnOx-based catalysts are systemically discussed in terms of crystal structure control,reasonable setting of working potential and electrolyte environment,optimal selection of acid-stable conductive supports,and self-healing engineering.Finally,future scientific challenges and research directions are outlined to guide the construction of advanced MnOx-based electrocatalysts for OER in acid.

Advances of manganese-oxides-based catalysts for indoor formaldehyde removal

Formaldehyde(HCHO)has been identified as one of the most common indoor pollutions nowadays.Manganese oxides(MnO_(x))are considered to be a promising catalytic material used in indoor HCHO oxidation removal due to their high catalytic activity,low-cost,and environmentally friendly.In this paper,the progress in developing MnO_(x)-based catalysts for HCHO removal is comprehensively reviewed for exploring the mechanisms of catalytic oxidation and catalytic deactivation.The catalytic oxidation mechanisms based on three typical theory models(Mars-van-Krevelen,Eley-Rideal and Langmuir-Hinshelwood)are discussed and summarized.Furthermore,the research status of catalytic deactivation,catalysts’regeneration and integrated application of MnO_(x)-based catalysts for indoor HCHO removal are detailed in the review.Finally,the technical challenges in developing MnO_(x)-based catalysts for indoor HCHO removal are analyzed and the possible research direction is also proposed for overcoming the challenges toward practical application of such catalysts.

Comparative structural and electrochemical properties of mixed P2/O′3-layered sodium nickel manganese oxide prepared by sol-gel and electrospinning methods:Effect of Na-excess content

The effect of Na-excess content in the precursor on the structural and electrochemical performances of sodium nickel manganese oxide(NNMO)prepared by sol-gel and electrospinning methods is investigated in this paper.X-ray diffraction results of the prepared NNMO without adding Na-excess content indicate sodium loss,while the mixed phase of P2/O′3-type layered NNMO presented after adding Na-excess content.Compared with the sol-gel method,the secondary phase of NiO is more suppressed by using the electrospinning method,which is further confirmed by field emission scanning electron microscope images.N_(2) adsorption-desorption isotherms show no remarkably difference in specific surface areas between different preparation methods and Na-excess contents.The analysis of X-ray absorption near edge structure indicates that the oxidation states of Ni and Mn are+2 and+4,respectively.For the electrochemical properties,superior electrochemical performance is observed in the NNMO electrode with a low Na-excess content of 5wt%.The highest specific capacitance is 36.07 F·g^(-1)at0.1 A·g^(-1)in the NNMO electrode prepared by using the sol-gel method.By contrast,the NNMO electrode prepared using the electrospinning method with decreased Na-excess content shows excellent cycling stability of 100%after charge-discharge measurements for 300 cycles.Therefore,controlling the Na excess in the precursor together with the preparation method is important for improving the electrochemical performance of Na-based electrode materials in supercapacitors.

Corrosion Mechanism of Alumina-magnesia Dry Materials for Smelting Manganese/chromium Steel in Coreless Medium Frequency Induction Furnaces

Alumina-magnesia dry materials are widely used in induction furnace linings, but they show different kinds of damage when melting different kinds of alloy steel. In this paper, the chemical composition, phase composition, and microstructure of the post-use dry materials for the working liners melting different kinds of steel were evaluated. Furthermore, the corrosion mechanism of the steel on the furnace lining materials was comprehensively analyzed. The findings reveal a significant ability of the Mn element in the molten steel to diffuse and penetrate into the refractories. Mn oxidizes to form MnO at the steel-refractory interface, and then forms a liquid phase with Al_(2)O_(3). The Cr element is dissolved into corundum and spinel of the refractories, resulting in lattice defects and structural damage of the materials. TiO2reacts with Al_(2)O_(3) to form Al_(2)TiO_(5), which plays a crucial role in preventing crack formation and propagation. Part of Ti4+dissolves into magnesia-alumina(MA), densifying the materials. TiO2also slows down the reaction between the Cr element and refractory components, further improving the corrosion resistance of the materials.

Structural,magnetic and antibacterial properties of manganese-substituted magnetite ferrofluids

Manganese-substituted magnetite ferrofluids(FFs)Mnx Fe_(1-x)Fe_(2)O_(4)(x=0–0.8)were prepared in this work through a chemical coprecipitation reaction.The controlled growth of FF nanomaterials for antibacterial activities is challenging,and therefore,very few reports are available on the topic.This research focuses on stabilizing aqueous FFs with the tetramethylammonium hydroxide surfactant to achieve high homogeneity.Morphological characterization reveals nanoparticles of 5–11 nm formed by the chemical reaction and nanocrystalline nature,as evident from structural investigations.Mn-substituted magnetic FFs are analyzed for their structural,functional,and antibacterial performance according to the Mn-substituent content.Optical studies show a high blue shift for Mn^(2+)-substituted Mnx Fe_(1-x)Fe_(2)O_(4)with the theoretical correlation of optical band gaps with the Mn content.The superparamagnetic nature of substituted FFs causes zero coercivity and remanence,which consequently influence the particle size,cation distribution,and spin canting.The structural and functional performance of the FFs is correlated with the antibacterial activity,finally demonstrating the highest inhibition zone formation for Mnx Fe_(1-x)Fe_(2)O_(4)FFs.

A Review of Influencing Factors of Damping Properties of High Manganese Steel

High manganese steel has wide prospects in industry due to their excellent mechanical and damping properties. The quenching structures of high manganese steel are ε-martensite, γ-austenite and α'-martensite. Researches show that the damping properties of high manganese steel are related to these microstructures. Besides, there are many ways to improve the damping property of damping alloys. This paper reviews the damping mechanism and the influences of the ad-dition of alloying elements, heat treatment, pre-deformation and other factors on their damping performance, hoping to provide methods and ideas for the study of damping properties of high manganese steel. .

Synthesis of zeolite A and zeolite X from electrolytic manganese residue,its characterization and performance for the removal of Cd^(2+)from wastewater

Electrolytic manganese residue(EMR)can cause serious environmental and biological hazards.In order to solve the problem,zeolite A(EMRZA)and zeolite X(EMRZX)were synthesized by EMR.The pure phase zeolites were synthesized by alkaline melting and hydrothermal two-step process,which had high crystallinity and excellent crystal control.And the optimum conditions for synthesis of zeolite were investigated:NaOH-EMR mass ratio=1.2,L/S=10,hydrothermal temperature=90℃,and hydrothermal time=6 h.Then,EMRZA and EMRZX showed excellent adsorption of Cd^(2+).When T=25℃,time=120min,pH=6,C0=518 mg·L^(-1),and quantity of absorbent=1.5 g·L^(-1),the adsorption capacities of EMRZA and EMRZX reached 314.2 and 289,5 mg·g^(-1),respectively,In addition,after three repeated adsorption-desorption cycles,EMRZA and EMRZX retained 80%and 74%of the initial zeolites removal rates,respectively.Moreover,adsorption results followed quasi-second-order kinetics and monolayer adsorption,which was regulated by a combination of chemisorption and intra-particle diffusion mechanisms.The adsorption mechanism was ions exchange between Cd^(2+)and Na+.In summary,it has been confirmed that EMRZA and EMRZX can be reused as highly efficient adsorbents to treat Cd^(2+)-contaminated wastewater.

Effects of Manganese on the Antioxidant System and Related Gene Expression Levels in the “Hong Yang” Kiwifruit Seedlings

To explore how manganese affects the antioxidant system and the expression levels of related genes of“Hong yang”seedlings,the leaves of its tissue cultured seedlings were taken as test materials,and single factor treatment was performed by changing the manganese chloride(MnCl_(2)·4H_(2)O)solution concentration when spraying the leaves.The expression levels of Mn-SOD,POD64 and POD27 genes in leaves were quantitatively analyzed by real-time quantitative PCR(qRT-PCR)at different determination times.Meanwhile,the contents of malondial-dehyde(MDA),hydrogen peroxide(H_(2)O_(2)),the activities of antioxidant enzymes,including catalase(CAT),peroxidase(POD),and superoxide dismutase(SOD).The results showed that the SOD,CAT,POD,ascorbate peroxidase(APX),and reduced glutathione(GSH)activities in leaves were the highest at 12 h post-treatment with 50μM MnCl_(2)·4H_(2)O.Furthermore,the contents of MDA and H_(2)O_(2) in leaves also peaked when the concentration of H_(2)O_(2) is 50μM,which is the minimum value.Additionally at 50μM Mn^(2+),the Mn-SOD and POD27 expression was up-regulated as compared to the control,which promoted the expression of their respective enzyme activities.However,POD64 expression increased with the increasing Mn^(2+) concentration.Therefore,50μM is the optimal concentration of Mn when exogenously applied on“Hong yang”,which improve the antioxidant enzyme activity and regulate the plant’s physiological and biochemical functions.