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On Hamiltonian Property of Cayley Digraphs

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Acta Mathematicae Applicatae Sinica 2024年第2期40卷 547-556页

作者： fang duan Qiong-xiang HUANG School of Mathematics Science Xinjiang Normal UniversityUrumqi 830017China College of Mathematics and Systems Science Xinjiang UniversityUrumqi 830017China

Let G be a finite group generated by S and C(G,S) the Cayley digraphs of G with connection set *** this paper,we give some sufficient conditions for the existence of hamiltonian circuit in C(G,S),where G=Zm×H is a semiproduct of Zmby a subgroup H of *** particular,if m is a prime,then the Cayley digraph of G has a hamiltonian circuit unless G=Zm×*** addition,we introduce a new digraph operation,called φ-semiproduct of Γ1by Γ2and denoted by Γ1×Γ_φΓ2,in terms of mapping φ:V(Γ2)→{1,-1}.Furthermore we prove that C(Zm,{a})×_φ C(H,S) is also a Cayley digraph if φ is a homomorphism from H to{1,-1} ≤ Zm~*,which produces some classes of Cayley digraphs that have hamiltonian circuits.

关键词： Cayley digraphs hamiltonian circuit external semidirect product

Removal of Cr(Ⅵ)by glutaraldehyde-crosslinked chitosan encapsulating microscale zero-valent iron:Synthesis,mechanism,and longevity

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Journal of Environmental Sciences 2024年第8期142卷 115-128页

作者： Yijun duan fang Liu Xiang Liu Miao Li School of Environment Tsinghua UniversityBeijing 100084China Transportation Institute of Inner Mongolia University Hohhot 010070China

Microscale zero-valent iron(mZVI)has shown great potential for groundwater Cr(Ⅵ)***,low Cr(Ⅵ)removal capacity caused by passivation restricted the wide use of *** prepared mZVI/GCS by encapsulating mZVI in a porous glutaraldehydecrosslinked chitosan matrix,and the formation of the passivation layer was alleviated by reducing the contact between zero-valent iron *** average pore diameter of mZVI/GCS was 8.775 nm,which confirmed the mesoporous characteristic of this *** of batch experiments demonstrated that mZVI/GCS exhibited high Cr(Ⅵ)removal efficiency in a wide range of pH(2-10)and temperature(5-35℃).Common groundwater coexisting ions slightly affected m ZVI/*** material showed great reusability,and the average Cr(Ⅵ)removal efficiency was 90.41%during eight *** this study,we also conducted kinetics and isotherms ***-second-order model was the most matched kinetics *** Cr(Ⅵ)adsorption process was fitted by both Langmuir and Freundlich isotherms models,and the maximum Langmuir adsorption capacity of m ZVI/GCS reached243.63 mg/g,which is higher than the adsorption capacities of materials reported in most of the previous ***,the column capacity for Cr(Ⅵ)removal of a mZVI/GCS-packed column was 6.4 times higher than that of a mZVI-packed column in a 50-day ***,mZVI/GCS with a porous structure effectively relieved passivation problems of mZVI and showed practical application prospects as groundwater Cr(Ⅵ)remediation material with practical application prospects.

关键词： Chitosan Glutaraldehyde mZVI Cr(Ⅵ) Groundwater

Influences of chemical reactions on polysulfide reduction reaction process on promotor surface in Li-S batteries

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Nano Research 2024年第4期17卷 2712-2718页

作者： Yufeng Luo Zhenhan fang Zixin Hong Shaorong duan Haitao Liu Hengcai Wu Qunqing Li Yuegang Zhang Shoushan Fan Wenhui duan Jiaping Wang Tsinghua-Foxconn Nanotechnology Research Center Tsinghua UniversityBeijing 100084China Department of Physics Tsinghua UniversityBeijing 100084China Laboratory of Computational Physics Institute of Applied Physics and Computational MathematicsBeijing 100088China Frontier Science Center for Quantum Information Tsinghua UniversityBeijing 100084China

Polar promotors have been proven effective in catalyzing the polysulfide(PS)reduction reaction(PSRR)process in lithium-sulfur(Li-S)***,the promotor surface tends to be poisoned due to the accumulation of insoluble discharging products of lithium disulfide(Li_(2)S_(2))and lithium sulfide(Li_(2)S)during Li-S battery ***,we investigate the detailed PSRR mechanism on the surface of manganese sulfides(MnS)as a representative promoter by performing in-situ Raman mapping *** catalytic ability of MnS enables thorough electrochemical reduction of PSs to Li_(2)S_(2) and Li_(2)S on the MnS *** generated Li_(2)S_(2) and Li_(2)S then adsorb the dissolved PSs via chemical reactions among sulfur species during the subsequent PSRR *** phenomenon mitigates promotor poisoning and continuously improves the reversible ***,the assembled Li-S cell demonstrates excellent electrochemical performance after introducing a conductive interlayer containing a thin piece of carbon nanotube film and MnS promotors.

关键词： promotors polysulfides chemical reactions catalytic ability in-situ Raman measurements

Sustained remission of Cronkhite-Canada syndrome after corticosteroid and mesalazine treatment: A case report

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World Journal of Clinical Cases 2024年第14期12卷 2431-2437页

作者： Ya-Lan Chen Rui-Yao Wang ling Mei Ran duan Department of Gastroenterology The Affiliated Hospital of Hebei UniversityBaoding 071000Hebei ProvinceChina Department of Thoracic Surgery The Affiliated Hospital of Hebei UniversityBaoding 071000Hebei ProvinceChina Department of Medical Imageology The Affiliated Hospital of Hebei UniversityBaoding 071000Hebei ProvinceChina

BACKGROUND Cronkhite-Canada syndrome(CCS)is a rare disease of unknown *** optimal treatment for CCS remains *** with corticosteroids is considered the mainstay treatment because of its high efficacy,but the therapeutic strategy for steroid-resistant CCS is not yet *** SUMMARY This is the case of an 81-year-old woman who was diagnosed with *** her severe diarrhea,nausea,vomiting,and hypoproteinemia,hormone therapy(40 mg/d)was administered,and the symptoms improved within 1 *** 3 mo,the patient had no obvious *** polyps were significantly reduced on review gastroscopy and colonoscopy,thus hormone reduction gradually *** hormone level was maintained at 10 mg/d after 6 *** the age of the patient and the side effects of hormones,the patient had no obvious ***,hormone drugs were discontinued,and mesalazine was administered orally at 3 g/*** patient's symptoms continued to improve after a follow-up of 5 *** Corticosteroids and mesalazine are potential treatment options for CCS.

关键词： Cronkhite-Canada syndrome Corticosteroids Mesalazine Gastrointestinal polyposis Case report

Oxidation behavior of 4774DD1 Ni-based single-crystal superalloy at 980℃ in air

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China Foundry 2024年第2期21卷 116-124页

作者： Yu fang Ya-zhou Li Qiang Yang Qun-gong He Xiu-fang Gong Qian duan Hai-yang Song Fu Wang Qiong-yuan Zhang Hong Zeng State Key Laboratory of Long-Life High Temperature Materials Dongfang Turbine Co.Ltd.Deyang 618000SichuanChina State Key Laboratory for Manufacturing System Engineering School of Mechanical EngineeringXi’an Jiaotong UniversityXi’an 710049China

The oxidation behavior of a novel Ni-based single-crystal 4774DD1 superalloy for industrial gas turbine applications was investigated by the isothermal oxidation at 980℃ and discontinuous oxidation weight gain *** phase constitution and morphology of surface oxides and the characteristics of the crosssection oxide film were analyzed by XRD,SEM and *** show that the oxidation kinetics of the 4774DD1 superalloy follows the cubic law,indicating its weak oxidation resistance at this *** the oxidation time increases,the composition of the oxide film evolves as following:One layer consisting of a bottom Al_(2)O_(3)sublayer and an upper(Al_(2)O_(3)+NiO)mixture sublayer after oxidized for 25 ***,two layers composed of an outermost small NiO discontinuous grain layer and an internal layer for 75 *** internal layer is consisted of the bottom Al_(2)O_(3)sublayer,an intermediate narrow CrTaO_(4)sublayer,and an upper(Al_(2)O_(3)+NiO)mixture *** two layers comprising an outermost relative continuous NiO layer with large grain size and an internal layer as the oxidation time increases to 125 *** internal layer is composed of the upper(Al_(2)O_(3)+NiO)mixture sublayer,an intermediate continuous(CrTaO_(4)+NiWO_(4))mixture sublayer,and a bottom Al_(2)O_(3)***,three layers consisting of an outermost(NiAl2O_(4)+NiCr2O_(4))mixture layer,an intermediate(CrTaO_(4)+NiWO_(4))mixture layer,and a bottom Al_(2)O_(3)layer for 200 h.

关键词： nickel-base single crystal superalloy oxidation kinetics oxide film microstructure mechanism

Effect of Humidity on Formaldehyde Oxidation over Ce_(0.8)Zr_(0.2)O_(y)Catalyst

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Journal of Wuhan University of Technology(Materials Science) 2024年第5期39卷 1108-1115页

作者： TANG Ruijiu YANG Zonglin LIU Xiang JIA Lijuan WANG fang duan Kaijiao LIU Tiancheng College of Chemistry and Environment Yunnan Minzu UniversityTechnology Innovation Team of Green Purification Technology for Industrial Waste GasEducation Department of YunnanKey Laboratory of Environmental Functional Materials of Yunnan Province Education DepartmentKunming 650504China

In the preparation of a series of Ce_(0.8)Zr_(0.2)O_(y)catalysts catalyzing the removal of formaldehyde,BET,H2-TPR,IR,SEM,XPS,and XRD were used to characterize the catalyst,and the influence of humidity on the catalyst activity was studied by adjusting the humidity during the *** experimental results showed that the formaldehyde removal rate increased with the increase of *** the humidity was higher than 50%,the formaldehyde removal rate decreased by 3%over that when the humidity was 50%.The characterization results showed that humidity facilitated the activation of oxygen and the formation of hydroxyl groups,which both promoted the formation and oxidative decomposition of intermediates and prevented the deposition of intermediates that clogged the pores,allowing more formaldehyde to be adsorbed and oxidized,which increased the activity of the *** provides new mechanistic evidence for the oxidation of formaldehyde and helps in the development of relatively low-cost materials for formaldehyde purification.

关键词： formaldehyde humidity Ce_(0.8)Zr_(0.2)O_(y) catalytic oxidation

Insight into the microbial community of denitrification process using different solid carbon sources: Not only bacteria

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Journal of Environmental Sciences 2024年第10期144卷 87-99页

作者： Congyu Li Yu ling Yanjie Zhang Haiyan Wang Huan Wang Guokai Yan Weiyang Dong Yang Chang Liang duan State Key Laboratory of Environmental Criteria and Risk Assessment Chinese Research Academy of Environmental SciencesBeijing 100012China College of Environmental Science and Engineering Tongji UniversityShanghai 200092China College of Water Sciences Beijing Normal UniversityBeijing 100875China Research Center of Environmental Pollution Control Technology Chinese Research Academy of Environmental ScienceBeijing 100012China State Environmental Protection Key Laboratory of Estuarine and Coastal Environment Chinese Research Academy of Environmental SciencesBeijing 100012China

There is a lack of understanding about the bacterial,fungal and archaeal communities’composition of solid-phase denitrification(SPD)*** investigated four SPD systems with different carbon sources by analyzing microbial gene sequences based on operational taxonomic unit(OTU)and amplicon sequence variant(ASV).The results showed that the corncob-polyvinyl alcohol sodium alginate-polycaprolactone(CPSP,0.86±0.04 mg NO_(3)^(−)-N/(g·day))and corncob(0.85±0.06 mg NO_(3)^(−)-N/(g·day))had better denitrification efficiency than polycaprolactone(PCL,0.29±0.11 mg NO_(3)^(−)-N/(g·day))and polyvinyl alcoholsodium alginate(PVA-SA,0.24±0.07 mg NO_(3)^(−)-N/(g·day)).The bacterial,fungal and archaeal microbial composition was significantly different among carbon source types such as Proteobacteria in PCL(OTU:83.72%,ASV:82.49%)and Rozellomycota in PVA-SA(OTU:71.99%,ASV:81.30%).ASV methods can read more microbial units than that of OTU and exhibit higher alpha diversity and classify some species that had not been identified by OTU such as Nanoarchaeota phylum,unclassified_f_Xanthobacteraceae genus,etc.,indicating ASV may be more conducive to understand SPD microbial *** co-occurring network showed some correlation between the bacteria fungi and archaea species,indicating different species may collaborate in SPD *** KEGG function prediction results were obtained in two bioinformatic methods generally and some fungi and archaea functions should not be ignored in SPD *** results may be beneficial for understanding microbial communities in SPD systems.

关键词： Solid-phase denitrification Solid carbon source Microbial community ASV analysis OTU analysis

Effect of dielectric material on the uniformity of nanosecond pulsed dielectric barrier discharge

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Plasma Science and Technology 2024年第9期26卷 79-87页

作者： Wenhao ZHOU Dongxuan ZHANG Xiaohui duan Xi ZHU Feng LIU Zhi fang College of Electrical Engineering and Control Science Nanjing Tech UniversityNanjing 211816People’s Republic of China

Dielectric barrier discharge(DBD)is considered as a promising technique to produce large volume uniform plasma at atmospheric pressure,and the dielectric barrier layer between the electrodes plays a key role in the DBD processes and enhancing discharge *** this work,the uniformity and discharge characteristics of the nanosecond(ns)pulsed DBD with dielectric barrier layers made of alumina,quartz glass,polycarbonate(PC),and polypropylene(PP)are investigated via discharge image observation,voltage-current waveform measurement and optical emission spectral *** analyzing discharge image by gray value standard deviation method,the discharge uniformity is quantitatively *** effects of the space electric field intensity,the electron density(Ne),and the space reactive species on the uniformity are studied with quantifying the gap voltage Ug and the discharge current Ig,analyzing the recorded optical emission spectra,and simulating the temporal distribution of Ne with a one-dimensional fluid *** is found that as the relative permittivity of the dielectric materials increases,the space electric field intensity is enhanced,which results in a higher Ne and electron temperature(Te).Therefore,an appropriate value of space electric field intensity can promote electron avalanches,resulting in uniform and stable plasma by the merging of electron ***,an excessive value of space electric field intensity leads to the aggregation of space charges and the distortion of the space electric field,which reduce the discharge *** surface roughness and the surface charge decay are measured to explain the influences of the surface properties and the second electron emission on the discharge *** results in this work give a comprehensive understanding of the effect of the dielectric materials on the DBD uniformity,and contribute to the selection of dielectric materials for DBD reactor and the realization of atmospheric pre

关键词： dielectric barrier discharge dielectric material uniformity discharge characteristics

Robust tantalum tuned perovskite oxygen electrode for reversible protonic ceramic electrochemical cells

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Rare Metals 2024年第7期43卷 3055-3065页

作者： Yu-Shi Feng Yu Shen fang Wang Chuan Tian Qin-Yi Hu Qian duan Jing-Wei Li Di Bao School of Materials Science and Engineering Changchun University of Science and TechnologyChangchun 130022China Zhongshan Institute of Changchun University of Science and Technology Zhongshan528437China State Key Laboratory of Rare Earth Resource Utilization Changchun Institute of Applied Chemistry Chinese Academy of SciencesChangchun 130022China Key Laboratory of Preparation and Applications of Environmental Friendly Materials Ministry of EducationJilin Normal UniversityChangchun 130103China

Perovskite oxides with diverse composition and structure have exhibited grand advances in boosting the oxygen reduction and evolution reaction(ORR/OER),which are essential for the reversible protonic ceramic electrochemical cell(R-PCEC)toward the sustainable hydrogen production and ***,enhancement of their activity and stability remains ***,we develop the Ta-regulated BaCo_(0.7)Fe_(0.3)O_(3-δ)perovskite oxygen electrode(Ba(Co_(0.7)Fe_(0.3))_(1-x)Ta_xO_(3-δ))with abundant oxygen defects and achieve the simultaneous enhancement in the electrocatalytic activity and stability toward ORR and ***-fabricated R-PCEC with(Ba(Co_(0.7)Fe_(0.3))_(0.9)Ta_(0.1)O_(3-δ))(BCFT10)oxygen electrode performs high power density of 1.47 W·cm^(-2)at 650℃in fuel cell mode,and the current density is up to-2.11 A·cm^(-2)at 1.4 V at 650℃in electrolysis mode,as well as the good stability in both the fuel cell and electrolysis ***,the cell also demonstrates a stable cycling operation between fuel cell and electrolysis mode,suggesting a great potential of BCFT10 as oxygen electrode material for R-PCECs.

关键词： Reversible protonic ceramic electrochemical cells Perovskite oxide Oxygen electrode Ta element doping Oxygen defects