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Oscillation properties of eigenfunctions for Sturm-Liouville problems with interface conditions via Prufer transformation

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Applied Mathematics(A Journal of Chinese Universities) 2024年第2期39卷 191-200页

作者： LI Zhi-yu LI Kun CAI Jin-ming QIN jian-fang zheng Zhao-wen School of Mathematical Sciences Qufu Normal UniversityQufu 273165China College of Mathematics and Systems Science Guangdong Polytechnic Normal UniversityGuangzhou 510665China

A class of Sturm-Liouville problems with discontinuity is studied in this *** oscillation properties of eigenfunctions for Sturm-Liouville problems with interface conditions are *** main method used in this paper is based on Prufer transformation,which is different from the classical ***,we give two examples to verify our main results.

关键词： Sturm-Liouville problem interface condition oscillatory solution

Solidification crack characteristics and sensitivity of peritectic steel

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Journal of Iron and Steel Research International 2024年第7期31卷 1668-1679页

作者： Ya-qiang Li jian-hua Liu Zi-ming Wang Ying-ying Li Yang He Xiao-wei Li Department of Automotive Engineering Hebei Vocational University of Technology and EngineeringXingtai 054000HebeiChina Hebei Special Vehicle Modification Technology Innovation Center Hebei Vocational University of Technology and EngineeringXingtai 054000HebeiChina Institute of Engineering Technology University of Science and Technology BeijingBeijing 100083China School of Petroleum and Natural Gas Engineering Changzhou UniversityChangzhou 213164JiangsuChina

The characteristics and sensitivity of solidification cracks in peritectic steels were investigated using directional solidifi-cation *** cracks were observed in both hypoperitectic steels(12CrlMoV,15CrMo)and hyper-peritectic steel(20CrMo)during solidification at growth velocities of 15,50,and 80 pm/*** the dendritic boundaries,sulphide precipitates were found,promoting crack *** on the statistical analysis of interdendritic cracks in peritectic steels,the area ratio(RA)of interdendritic cracks in a directional solidification structure was proposed to evaluate the crack sensitivity of peritectic ***,the crack sensitivities of peritectic steels(12CrlMoV,15CrMo,and 20CrMo)were tested,evaluated,and compared with the surface crack rates of three types of steels produced from a steel *** results demonstrated that RA was in good agreement with that of the steel plant,and the crack sensitivity of 12CrlMoV steel was the strongest,followed by that of 15CrMo and 20CrMo ***,RA can be used to evaluate the crack sensitivity of peritectic steel.

关键词： Peritectic steel-Directional solidification Growth velocity Dendritic structure Solidification crack Crack sensitivity

Effects of maternal methyl donor intake during pregnancy on ileum methylation and function in an intrauterine growth restriction pig model

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Journal of Animal Science and Biotechnology 2024年第3期15卷 1173-1189页

作者： Yan Lin jiangnan Wu Yong Zhuo Bin Feng zhengfeng Fang Shengyu Xu jian Li hua Zhao De Wu Lun hua Lianqiang Che Key Laboratory of Animal Disease‑Resistance Nutrition Animal Nutrition InstituteSichuan Agricultural UniversityChengdu 611130SichuanChina

Background Intrauterine growth retardation(IUGR)affects intestinal growth,morphology,and function,which leads to poor growth performance and high *** present study explored whether maternal dietary methyl donor(MET)supplementation alleviates IUGR and enhances offspring’s growth performance by improving intestinal growth,function,and DNA methylation of the ileum in a porcine IUGR *** Forty multiparous sows were allocated to the control or MET diet groups from mating until *** farrowing,8 pairs of IUGR and normal birth weight piglets from 8 litters were selected for sampling before suckling *** The results showed that maternal MET supplementation tended to decrease the IUGR incidence and increased the average weaning weight of ***,maternal MET supplementation significantly reduced the plasma concentrations of isoleucine,cysteine,urea,and total amino acids in sows and newborn *** also increased lactase and sucrase activity in the jejunum of newborn *** addition resulted in lower ileal methionine synthase activity and increased betaine homocysteine S-methyltransferase activity in the ileum of newborn *** methylation analysis of the ileum showed that MET supplementation increased the methyla-tion level of DNA CpG sites in the ileum of newborn ***-regulated differentially methylated genes were enriched in folic acid binding,insulin receptor signaling pathway,and endothelial cell *** contrast,up-regulated methylated genes were enriched in growth hormone receptor signaling pathway and nitric oxide biosyn-thetic *** Maternal MET supplementation can reduce the incidence of IUGR and increase the weaning litter weight of piglets,which may be associated with better intestinal function and methylation status.

关键词： Ileum Intrauterine growth restriction Methyl donor Methylation Sows

Effect of alumina occurrence form on metallurgical properties of hematite and magnetite pellets

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Journal of Iron and Steel Research International 2024年第4期31卷 797-809页

作者： jian Pan Chen-mei Tang Cong-cong Yang De-qing Zhu zheng-qi Guo Wei-qun huang School of Minerals Processing and Bioengineering Central South UniversityChangsha 410083HunanChina Exploration and Development of Geology and Mineral Resources Co. Ltd.Nanchang 330030JiangxiChina

The effect of alumina occurrence form on the metallurgical properties of both hematite and magnetite pellets was investigated at the same Al_(2)O level of 2 wt.%,including reduction index(RI),low-temperature reduction disintegration index(RDI),reduction swelling index(RSI),and high-temperature softening-dripping *** mineralogy of fired pellets was also studied to reveal the influence of alumina occurrence form on the phase composition and *** the results,the alumina occurrence form presents tremendous impacts on the metallurgical perfor-mance of both magnetite and hematite *** of all alumina occurrence forms contributes to inferior reducibility of pellets,especially in the case of gibbsite for magnetite pellets with a RI of 58.4%and kaolinite for hematite pellets with a RI of 56.8%.However,addition of all alumina occurrence forms improves the RDI of magnetite pellets,while there is no significant difference among various alumina occurrence *** contrast,alumina occurrence forms have little influence on the RDI of hematite *** presence of free alumina,gibbsite,and kaolinite tends to improve the RSI of hematite and magnetite pellets,whereas hercynite gives the opposite trend with a RSI of 25.6%.For softening-dripping performance of magnetite pellets,all alumina occurrence forms contribute to narrower softening-melting ***,alumina,gibbsite,and kaolinite give narrower softening-dripping interval,at 229,217,and 88℃,respectively,whereas addition of hercynite results in the largest melting range at 276℃ due to its high melting *** hematite pellets,free alumina,gibbsite,and hercynite tend to enlarge melting range,whereas kaolinite contributes to lower dripping temperature of 1148℃ and narrow softening-dripping interval of 88℃ due to the formation of a greater amount of slag phase at high temperatures.

关键词： Oxidized pellet Magnetite Hematite Alumina occurrence form Metallurgical performance Blast furnace

Cobalt-based heterogeneous catalysts for photocatalytic carbon dioxide reduction

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Tungsten 2024年第2期6卷 410-421页

作者： Hong Yuan jian-hua Mei Yun-Nan Gong Di-Chang Zhong Tong-Bu Lu MOE International Joint Laboratory of Materials Microstructure Institute for New Energy Materials and Low Carbon TechnologiesSchool of Materials Science and EngineeringTianjin University of TechnologyTianjin 300384China

Solar light-driven CO_(2)reduction to high value-added chemicals has considered as an outstanding way to solve energy crisis and climate ***,various photocatalysts have been developed to achieve this *** them,cobaltbased heterogeneous catalysts have attracted great interest because of their promising performance,product selectivity and ***,we systematically summarize the research progress of various cobalt-based heterogeneous catalysts for the photoreduction of CO_(2),such as single-atom cobalt,and cobalt-based oxides,nitrides,sulfi des,phosphides,metal-organic frameworks and covalent-organic ***,the advantages and structure-activity relationship of these catalysts in photocatalytic CO_(2)reduction reaction are ***,the challenges and prospects for constructing cobaltbased heterogeneous catalysts with high effi ciency are highlighted.

关键词： Cobalt Heterogeneous catalysts CO_(2)reduction Photocatalysis

Selective and asymmetric ion transport in covalent organic framework-based two-dimensional nanofluidic devices

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International Journal of Smart and Nano Materials 2024年第1期15卷 186-197页

作者： Li-Qiu huang Shuang Chen Ri-jian Mo Zhong-Qiu Li Xing-hua Xia State Key Laboratory of Analytical Chemistry for Life Science School of Chemistry and Chemical EngineeringNanjing UniversityNanjingChina

Two-dimensional(2D)covalent organic framework(COF)mem-branes featuring well-aligned and programmable vertical nano-channels have emerged as a promising candidate for advanced nanofluidic devices and showcased vast potential in the fields of smart-gating,ion-separation,and ***,the transverse interlayer nanochannels with a height of sub-nanometer-scale in 2D-COF membranes have scarcely been studied in ***,we report the ion transport characteristics in 2D interlayer nanochannels of protonated CoF *** dis-tinct surface-charge-governed ionic conductance in domination of electrolyte concentration below 1o-3 M as well as the exceptional anion/cation(Cl^(-)/K^(+))selectivity is revealed due to the pronounced charge and nano-confinement ***,evident ion current rectification is witnessed when incorporating asymmetric geometry into the system,which is attributed to the dynamic process of ion enrichment and dissipation within the protonated *** work offers immense prospects for 2D-COF membranes in the fields of biomimetic nanofluidic devices and cutting-edge electronic devices.

关键词： Two-dimensional covalent organic framework interlayernanochannels ion transport characteristics nanofluidic device

Optimal V_(2)O_(3) extraction by sustainable vanadate electrolysis in molten salts

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Tungsten 2024年第1期6卷 141-149页

作者： Bao-Yan Feng Zhong-hua Zhao Yong-zheng Jia Jia-Liang An Ming-Yong Wang State Key Laboratory of Advanced Metallurgy University of Science and Technology BeijingBeijing 100083China Beijing Key Laboratory of Green Recovery and Extraction of Rare and Precious Metals University of Science and Technology BeijingBeijing 100083China

Recently,an environmentally friendly electrolysis process of soluble vanadates is proposed and successfully confirmed for V_(2)O_(3) *** this paper,the solubilities of various vanadates(***_(3),Na_(4)V_(2)O_(7) and Na_(3)VO_(4))in NaCl molten salt are *** dependences of V_(2)O_(3) extraction on vanadate form,anode material and molten salt system are studied.A long-term electrolysis is carried *** result indicates that the solubilities of all vanadates are high and meet electrolytic *** to Na_(4)V_(2)O_(7) and Na_(3)VO_(4),NaVO_(3) exhibits larger current efficiency and lower electricity *** using SnO_(2) anode instead of graphite anode,the current efficiency of NaVO_(3) electrolysis can be increased to 58.1%and carbon pollution is avoided at 700℃.The extraction rate of V_(2)O_(3) reaches 81.3%after long-term electrolysis of 51 *** work optimizes the electrochemical preparation process of V_(2)O_(3) from various vanadates and contributes to the improvement of current efficiency and extraction rate.

关键词： Molten salt electrolysis Vanadate Vanadium trioxide Current efficiency

Multi-Branch Fault Line Location Method Based on Time Difference Matrix Fitting

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Energy Engineering 2024年第1期121卷 77-94页

作者： hua Leng Silin He jian Qiu Feng Liu Xinfei huang Jiran Zhu School of Electrical and Information Engineering Hunan UniversityChangsha410082China Distribution Network Technical Center State Grid Hunan Electric Power Research InstituteChangsha410007China Technical Center China Energy Construction Group Hunan Thermal Power ConstructionZhuzhou412011China School of Electrical and Information Engineering Changsha University of Science and TechnologyChangsha410076China

The distribution network exhibits complex structural characteristics,which makes fault localization a challenging *** when a branch of the multi-branch distribution network fails,the traditional multi-branch fault location algorithm makes it difficult to meet the demands of high-precision fault localization in the multi-branch distribution network *** this paper,the multi-branch mainline is decomposed into single branch lines,transforming the complex multi-branch fault location problem into a double-ended fault location *** on the different transmission characteristics of the fault-traveling wave in fault lines and non-fault lines,the endpoint reference time difference matrix S and the fault time difference matrix G were *** time variation rule of the fault-traveling wave arriving at each endpoint before and after a fault was comprehensively *** realize the fault segment location,the least square method was *** was used to find the first-order fitting relation that satisfies the matching relationship between the corresponding row vector and the first-order function in the two matrices,to realize the fault segment ***,the time difference matrix is used to determine the traveling wave velocity,which,combined with the double-ended traveling wave location,enables accurate fault location.

关键词： Multi-branch lines distribution network fault location double-ended traveling wave positioning least square method

A reverse particle grading strategy for design and fabrication of porous SiC ceramic supports with improved strength

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Journal of Advanced Ceramics 2024年第7期13卷 1011-1022页

作者： zheng Liang Han Zhang Yichuan Li Wenkang Zhang jian Zhou Qilin Gu Zhaoxiang Zhong Weihong Xing State Key Laboratory of Materials-Oriented Chemical Engineering National Engineering Research Center for Special Separation MembraneNanjing Tech UniversityNanjing 211816China Nanjing Membrane Application Institute Co. Ltd.Nanjing 210009China

Porous ceramics usually require high mechanical strength and maximized porosity simultaneously,while for conventional particle grading strategies,it is highly challenging to meet both *** this end,a reverse particle grading strategy was developed based on the linear packing model by unusually introducing coarse particles(d_(50)=16μm)into a fine particle(d50=5μm)*** the extrusion and sintering process,tubular porous SiC ceramic supports with improved mechanical strength were successfully *** effects of coarse particles on the rheological properties of the ceramic paste and the macroscopic properties and microstructure of the SiC supports were systematically *** an increase in the content of coarse SiC particles to 30 wt%,the pressure generated during extrusion decreased from 5.5±0.2 to 1.3±0.1 ***,the bending strength of the tubular supports increased from 36.6±5.6 to 49.1±4.5 MPa when 20 wt%coarse powder was *** notably improved mechanical strength was attributed to the distribution of coarse particles that prolonged the route of crack ***,the optimized tubular supports had an average pore size of 1.2±0.1μm,an open porosity of 45.1%±1.6%,and a water permeability of 7163±150 L/(m^(2)·h·bar)as well as good alkali and acid corrosion ***,the strategy was proven to be feasible for the scale-up fabrication of 19-channel SiC tubular porous ceramic supports.

关键词： porous SiC ceramic tubular ceramic support reverse particle grading reaction bonding chemical stability