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Catalytic oxidation of toluene by manganese oxides:Effect of K^(+)doping on oxygen vacancy

Journal of Environmental Sciences 2024年第8期142卷 43-56页

作者： Zhenzhen Huang Haiyang Li xuejun zhang Yanli Mao Yinghan Wu Wei Liu Hongrun Gao Mengru zhang Zhongxian Song Faculty of Environmental and Municipal Engineering Henan Key Laboratory of Water Pollution Control and Rehabilitation TechnologyHenan University of Urban ConstructionPingdingshan 467036China College of Environmental and Safety Engineering Shenyang University of Chemical TechnologyShenyang 110142China

Alkali metal potassium was beneficial to the electronic regulation and structural stability of transition metal ***,K ions were introduced into manganese oxides by different methods to improve the degradation efficiency of *** results of activity experiments indicated that KMnO_(4)-HT(HT:Hydrothermal method)exhibited outstanding low-temperature catalytic activity,and 90%conversion of toluene can be achieved at 243℃,which was 41℃and 43℃lower than that of KNO_(3)-HT and Mn-HT,*** largest specific surface area was observed on KMnO_(4)-HT,facilitating the adsorption of *** formation of cryptomelane structure over KMnO_(4)-HT could contribute to higher content of Mn^(3+)and lattice oxygen(Olatt),excellent low-temperature reducibility,and high oxygen mobility,which could increase the catalytic ***,two distinct degradation pathways were ***Ⅰ(KMnO_(4)-HT):toluene→benzyl→benzoic acid→carbonate→CO_(2)and H2O;PathwayⅡ(Mn-HT):toluene→benzyl alcohol→benzoic acid→phenol→maleic anhydride→CO_(2)and *** intermediates were detected on KMnO_(4)-HT,indicating its stronger oxidation capacity of toluene,which was originated from the doping of K^(+)and the interaction between *** intermediates were observed on Mn-HT,which can be attributed to the weaker oxidation ability of pure *** results indicated that the doping of K^(+)can improve the catalytic oxidation capacity of toluene,resulting in promoted degradation of intermediates during the oxidation of toluene.

关键词： Catalytic oxidation Preparation method Cryptomelane Mn^(3+)and lattice oxygen

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Multicolor Ramsey Number of Stars Versus a Path

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Journal of Mathematical Research with Applications 2024年第04期44卷 465-469页

作者： xuejun zhang Xinmin HOU School of Data Science University of Science and Technology of China School of Mathematical Sciences University of Science and Technology of China CAS Key Laboratory of Wu Wen-Tsun Mathematics University of Science and Technology of China Hefei National Laboratory University of Science and Technology of China

For given simple graphs H1,H2,...,Hc,the multicolor Ramsey number R（H1,H2,...,Hc） is defined as the smallest positive integer n such that for an arbitrary edge-decomposition{Gi}ci=1of the complete graph K_n,at least one Gihas a subgraph isomorphic to *** m,n1,n2,...,nc be positive integers andΣ=Σci=1（ni-1）.Some bounds and exact values of R(K1,n1,...,K1,nc,Pm) have been obtained in *** （Graphs Combin.,2020） conjectured that ifΣ?≡0 （mod m-1） andΣ+1≥（m-3）2,then R(K1,n1,...,K1,nc,Pm)=Σ+*** this note,we give a new lower bound and some exact values of R(K1,n1,...,K1,nc,Pm) provided m≤Σ,Σ≡k （mod m-1）,and 2≤k≤*** results partially confirm Wang’s conjecture.

关键词： Ramsey number star path

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Influence of surface acidity and chemical valence on low temperature activity over Pt-HSiW/CeO_(2) for catalytic combustion of chlorobenzene

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Journal of Rare Earths 2024年第9期42卷 1693-1703,I0002页

作者： Zhongxian Song Zepeng Liu xuejun zhang Yanli Mao Wei Liu Chunxiang Gao Haiyang Li Xia zhang Changrui Han Zhenzhen Huang Key Laboratory of Carbon Emission Reduction and Combined Air Pollution Control Technology Faculty of Environmental and Municipal EngineeringHenan University of Urban ConstructionPingdingshan467036China College of Environmental and Safety Engineering Shenyang University of Chemical TechnologyShenyang110142China

Pt-HSiW/CeO_(2) catalysts were prepared for chlorobenzene(CB) catalytic combustion by hydrothermal method at different calcination temperatures,and the effects of the surface acidity and chemical valence on the catalytic activity were *** results show that the catalyst calcined at 450℃(Cat-B)exhibits the outstanding catalytic performance,and the Cat-B catalyst possesses 90% conversion of CB at148℃.The excellent catalytic activity of Cat-B is attributed to more Ce^(3+)/(Ce^(3+)+Ce^(4+)),Pt~0/(Pt^(0)+Pt^(2+)),O_(ads)/(O_(latt)+O_(ads)) and Lewis acid *** degradation mechanism is proposed based on the analysis of the intermediates with the following reaction pathway:chlorobenzene→phenates/benzoquinone→acetate→maleate→CO_(2)+H_(2)O.

关键词： Pt-HSiW/CeO_(2) Catalytic combustion Chlorobenzene Acid sites Rare earths

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GENERALIZED FORELLI-RUDIN TYPE OPERATORS BETWEEN SEVERAL FUNCTION SPACES ON THE UNIT BALL OF C^(N)

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Acta Mathematica Scientia 2024年第4期44卷 1301-1326页

作者： xuejun zhang Yuting GUO Hongxin CHEN Pengcheng TANG College of Mathematics and Statistics Hunan Normal University.Changsha 410081China School of Mathematics Hunan UniversityChangsha 410082China School of Mathematics and Computational Science Hunan University of Science and TechnologyXiangtan 411201China

In this paper,we investigate sufficient and necessary conditions such that generalized Forelli-Rudin type operators T_(λ,τ,k),S_(λ,τ,k),Q_(λ,τ,k)and R_(λ,τ,k)are bounded between Lebesgue type *** order to prov... 详细信息

关键词： Forelli-Rudin type operator L^(p,q,s,k)(B_(n))space boundedness unit ball

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Design and parameters optimization of the curved sieve for an air suction jujube harvester

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International Journal of Agricultural and Biological Engineering 2024年第2期17卷 132-139页

作者： Shenghe Bai Yanwei Yuan Kang Niu Liming Zhou Bo Zhao Liguo Wei Lijing Liu xuejun zhang College of Engineering China Agricultural UniversityBeijing 100083China National Key Laboratory of Agricultural Equipment Technology Chinese Academy of Agricultural Mechanization Sciences Group Co.Ltd.Beijing 100083China College of Mechanical and Electrical Engineering Xinjiang Agricultural UniversityUrumqi 830052China

In order to improve the screening performance and cleaning effect of the jujube harvesting machinery cleaning device,a vibrating curved screen device was designed in this *** analyzing the structure mechanism of the curved sieve body,it was obtained that the arc-shaped mesh hole spacing S was 15-25 mm and the curved mesh hole curvature U was 90°-150°.By exploring the movement state and stress of jujube and impurities on the curved sieve body,it was determined that the horizontal spacing L of the curved layer sieve was 30 mm and the vertical spacing H was 45-65 *** the vertical spacing H of the curved layer sieve,the curvature U of the curved mesh hole,and the spacing S of the curved mesh hole as the experimental factors,considering the screening efficiencyαand the impurity contentβof the jujube as the response values,the three-factor three-level quadratic regression orthogonal experiment was designed,establishing the regression mathematical model of each factor and response value,and the multiple target optimization algorithm of Design-expert software was used to optimize various *** results showed that the influence factors on the screening efficiency were in the descending order as:the arc screen spacing,the vertical spacing of the curved layer screen,and the curved screen hole curvature;The significant factors affecting the impurity content of jujube were in the descending order as:the arc screen spacing,the curved screen hole curvature,and the vertical spacing of the curved layer *** experimental results were verified by the optimized combination of parameters:when the vertical spacing H of the curved layer screen was 65 mm,the curved screen hole curvature U was 110°,and the arc screen spacing S was 23 mm,the average screening efficiencyαin the test was 91.09%.The relative error between the experimental verification value and the theoretical optimization value was 1.36%,which was less than 5%.The impurity content of jujubeβin the test w

关键词： jujube harvesting cleaning device curved sieve sieve structure conveying pipe mathematical model

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Non-invasive imaging of pathological scars using a portable handheld two-photon microscope

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Chinese Medical Journal 2024年第3期137卷 329-337页

作者： Yang Han Yuxuan Sun Feili Yang Qingwu Liu Wenmin Fei Wenzhuo Qiu Junjie Wang Linshuang Li xuejun zhang Aimin Wang Yong Cui Graduate School Chinese Academy of Medical SciencesPeking Union Medical CollegeBeijing 100730China Department of Dermatology China-Japan Friendship HospitalBeijing 100029China College of Engineering Peking UniversityBeijing 100871China School of Chemical Biology and Biotechnology State Key Laboratory of Chemical OncogenomicsPeking University Shenzhen Graduate SchoolShenzhenGuangdong 518055China Department of Dermatology The First Affiliated Hospital of Nanchang UniversityNanchangJiangxi 330006China Academy for Advanced Interdisciplinary Studies Peking UniversityBeijing 100871China College of Future Technology Peking UniversityBeijing 100871China Beijing Transcend Vivoscope Biotech Beijing 100085China Department of Dermatology The First Affiliated Hospital of Anhui Medical UniversityHefeiAnhui 230001China Institute of Dermatology Anhui Medical UniversityHefeiAnhui 230001China School of Electronics Peking UniversityBeijing 100871China

Background:Pathological scars are a disorder that can lead to various cosmetic,psychological,and functional problems,and no effective assessment methods are currently *** and treatment of pathological scars are based on cutaneous manifestations.A two-photon microscope(TPM)with the potential for real-time non-invasive assessment may help determine the under-surface pathophysiological conditions in *** study used a portable handheld TPM to image epidermal cells and dermal collagen structures in pathological scars and normal skin in vivo to evaluate the effectiveness of treatment in scar ***:Fifteen patients with pathological scars and three healthy controls were *** was performed using a portable handheld *** indexes were extracted from two dimensional(2D)and three dimensional(3D)perspectives,including collagen depth,dermo-epidermal junction(DEJ)contour ratio,thickness,orientation,and occupation(proportion of collagen fibers in the field of view)of *** depth-dependent indexes were computed through the 3D second harmonic generation image and three morphology-related indexes from the 2D *** assessed index differences between scar and normal skin and changes before and after ***:Pathological scars and normal skin differed markedly regarding the epidermal morphological structure and the spectral characteristics of collagen *** indexes were employed to distinguish between normal skin and scar *** significant differences were found in average depth(t=9.917,P<0.001),thickness(t=4.037,P<0.001),occupation(t=2.169,P<0.050),orientation of collagen(t=3.669,P<0.001),and the DEJ contour ratio(t=5.105,P<0.001).Conclusions:Use of portable handheld TPM can distinguish collagen from skin tissues;thus,it is more suitable for scar imaging than reflectance confocal ***,a TPM may be an auxiliary tool for scar treatment selection and assessing treatment efficacy.

关键词： Scars Two-photon microscope Two-photon excitation fluorescence Second harmonic generation microscopy

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脑电信号多特征融合与卷积神经网络算法研究

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计算机工程与应用 2024年第8期60卷 148-155页

作者：宋世林张学军南京邮电大学电子与光学工程学院、柔性电子(未来技术)学院南京210023 南京邮电大学射频集成与微组装技术国家地方联合工程实验室南京210023

针对脑电信号(electroencephalogram,EEG)运动想象中单一特征无法多维表征信号中的信息导致的分类准确率不高的问题,提出一种基于样本熵和共空间模式特征融合的特征提取算法。算法先对原始脑电信号进行小波包分解,从中选择包含μ和β节... 详细信息

针对脑电信号(electroencephalogram,EEG)运动想象中单一特征无法多维表征信号中的信息导致的分类准确率不高的问题,提出一种基于样本熵和共空间模式特征融合的特征提取算法。算法先对原始脑电信号进行小波包分解,从中选择包含μ和β节律的分量进行重构,然后分别提取重构信号的样本熵和CSP(common spatial pattern,CSP)特征,将两者融合组成新的特征向量,使用所设计的一维卷积神经网络对其进行识别获得分类结果。所提方法在2003年BCI Dataset III中获得了91.66%的分类准确率,在2008年BCI Dataset A中获得了85.29%的平均分类准确率。与近年来文献中提出的多特征融合算法相比,准确率提高了7.96个百分点。

关键词：脑电信号运动想象小波包重构样本熵共空间模式卷积神经网络

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航空典型金属材料增材制造组织、缺陷、表面、构型研究进展

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航空材料学报 2024年第1期44卷 1-14页

作者：张学军陈冰清中国航发增材制造技术创新中心北京100095 中国航发北京航空材料研究院3D打印研究与工程技术中心北京100095

增材制造是一种集激光、数字化、材料等学科为一体的新型制造技术,具有降维制造、复杂成型、材料利用率高等优点,是材料加工领域中最具应用前景的技术之一,金属增材制造技术已在航空领域得到广泛研究和应用,国内外学者在航空金属材料增... 详细信息

增材制造是一种集激光、数字化、材料等学科为一体的新型制造技术,具有降维制造、复杂成型、材料利用率高等优点,是材料加工领域中最具应用前景的技术之一,金属增材制造技术已在航空领域得到广泛研究和应用,国内外学者在航空金属材料增材制造方面的研究不断深入。中国航发增材制造技术创新中心在金属增材制造结构四要素——组织、缺陷、表面、构型方面开展了大量研究并获得一些数据,发现了一些现象和规律,包括组织接续生长特征及其对力学性能的影响;典型材料增材制造常见缺陷(气孔、裂纹、未熔合)特征、形成原因及其对力学性能特别是疲劳性能的影响机制;零件表面粗糙度与成形角度的关系及对疲劳性能的影响;金属增材制造构型的影响因素。在此基础上,总结了金属增材制造发展中存在的问题,对下一步重点提出了建议,并对未来研究工作提出了展望。

关键词：增材制造组织缺陷表面构型

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基于多域信息融合的脑电情感识别研究

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电子测量技术 2024年第2期47卷 168-175页

作者：王泽田张学军南京邮电大学电子与光学工程学院、柔性电子(未来技术)学院南京210023 南京邮电大学射频集成与微组装技术国家地方联合工程实验室南京210023

脑电信号识别方法较少将空间、时间和频率信息相融合,为了充分挖掘脑电信号包含的丰富信息,本文提出一种多域信息融合的脑电情感识别方法。该方法利用二维卷积神经网络和一维卷积神经网络相结合的并行卷积神经网络(PCNN)模型学习脑电信... 详细信息

脑电信号识别方法较少将空间、时间和频率信息相融合,为了充分挖掘脑电信号包含的丰富信息,本文提出一种多域信息融合的脑电情感识别方法。该方法利用二维卷积神经网络和一维卷积神经网络相结合的并行卷积神经网络(PCNN)模型学习脑电信号的空间、时间和频率特征,来对人类情感状态进行分类。其中,2D-CNN用于挖掘相邻EEG通道间的空间和频率信息,1D-CNN用于挖掘EEG的时间和频率信息。最后,将两个并行卷积模块提取的信息融合进行情感识别。在数据集SEED上的情感三分类实验结果表明,融合空间、时间、频率特征的PCNN整体分类准确率达到了98.04%,与只提取空频信息的2D-CNN和提取时频信息的1D-CNN相比,准确率分别提高了1.97%和0.60%。并于最近的类似工作相比,本文提出的方法对于脑电情感分类具有一定的优越性。

关键词：脑电信号多域信息融合情感识别并行卷积神经网络

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基于FEM-SPH耦合的卷辊式耕层残膜回收部件结构优化与试验

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农业工程学报 2024年第10期40卷 55-65页

作者：张学军郭磊史增录鄢金山刘小鹏张朝书刘蕾新疆农业大学机电工程学院乌鲁木齐830052 新疆智能农业装备重点实验室乌鲁木齐830052 阿拉尔市天典农机制造有限责任公司阿拉尔843300

针对棉田耕作层内残膜力学性能差及膜土分离困难,残膜拾净率低和回收的残膜含土量高等问题,该研究对卷辊式残膜回收部件进行优化。在分析起膜捡膜工作过程和建立卷辊弹齿与膜土团聚体之间动力学关系的基础上,采用有限元法(finite elemen... 详细信息

针对棉田耕作层内残膜力学性能差及膜土分离困难,残膜拾净率低和回收的残膜含土量高等问题,该研究对卷辊式残膜回收部件进行优化。在分析起膜捡膜工作过程和建立卷辊弹齿与膜土团聚体之间动力学关系的基础上,采用有限元法(finite element method,FEM)和光滑粒子流体动力学(smoothed particle hydrodynamics,SPH)耦合算法,建立卷辊弹齿-膜土团聚体接触计算模型,探究卷辊弹齿与膜土团聚体之间相互作用机理,分析卷辊弹齿接触膜土团聚体后残膜受力程度和土壤扰动程度的变化规律。以卷辊回转半径、弹齿直径、弹齿顶端折弯角为试验因素,以残膜平均峰值应力及土壤最大应变为指标开展仿真试验,分析各因素对指标的影响规律并对卷辊弹齿结构参数进行优化,获得卷辊弹齿最优结构参数为:卷辊回转半径100 mm、弹齿直径5 mm、弹齿顶端折弯角42°,此时残膜平均峰值应力为0.1201 MPa,土壤最大应变为3.7584。为了验证优化后卷辊弹齿的捡拾作业性能,以拾净率和含土率为试验指标进行田间试验,结果表明:机具拾净率为80.34%,含土率为37.13%,与初代研制的样机相比拾净率提升了8.74个百分点,含土率下降了12.18个百分点,机具作业性能明显提升且试验指标达到设计要求。本文建立的有限元模型可为残膜回收机关键部件的结构优化提供参考。

关键词：农业机械优化残膜回收弹齿 FEM-SPH 膜土团聚体

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