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On traceable iterated line graph and hamiltonian path index

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Applied Mathematics(A Journal of Chinese Universities) 2024年第2期39卷 239-252页

作者： niu Zhao-hong XIOnG Li-ming YAnG Wei-hua School of Mathematical Sciences Shanxi UniversityTaiyuan 030006China School of Mathematics and Statistics Beijing Key Laboratory on MCAACIBeijing Institute of TechnologyBeijing 100081China Department of Mathematics Taiyuan University of TechnologyTaiyuan 030024China

Xiong and Liu[21]gave a characterization of the graphs G for which the n-iterated line graph L^(n)(G)is hamiltonian,for n≥*** this paper,we study the existence of a hamiltonian path in L^(n)(G),and give a characterization of G for which L^(n)(G)has a hamiltonian *** applications,we use this characterization to give several upper bounds on the hamiltonian path index of a graph.

关键词： iterated line graph traceable hamiltonian index hamiltonian path index

Intraspecific floral colour variation in three Pedicularis species

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Plant Diversity 2024年第2期46卷 274-279页

作者： Qiu-Yu Zhang Zhe Chen Hang Sun Yang niu State Key Laboratory of Plant Diversity and Specialty Crops Kunming Institute of BotanyChinese Academy of SciencesKunming 650201YunnanChina University of Chinese Academy of Sciences Beijing 100049China

Flower constancy describes the phenomenon that pollinators tend to successively visit flowers of a single species during foraging,reducing reproductive interference in natural *** extent of flower constancy is largely determined by the floral traits of co-flowering *** higher inter-specific and lower intraspecific differences of floral traits should contribute to a higher level of flower ***,previous studies mainly focused on interspecific difference,and the intraspecific variation(consistency)of floral traits received much less *** hypothesise that selection may favour lower intraspecific floral trait variation in communities composed of multiple co-flowering *** investigated the floral colour variation of three focal Pedicularis species that share pollinators in 19communities composed of either single or multiple Pedicularis *** was quantified using image-based colour analysis as perceived by *** found that most of the intrapopulation floral colour variation was below the colour discrimination threshold of bumblebees,implying strongly constrained by the visual selection by *** to the hypothesis,there is no significant difference in intraspecific floral colour variation between different community *** may be due to the relatively large interspecific floral colour differences of most co-flowering *** influence of community context on intraspecific variation may be reflected in floral traits other than colours.

关键词： Flower constancy Floral colour variation Plantepollinator interactions Pollinator vision

An advanced 2D/3D g-C_(3)n_(4)/TiO_(2)@MnO_(2) multifunctional membrane for sunlight-driven sustainable water purification

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nano Research 2024年第4期17卷 2368-2380页

作者： Fan Yu Chunjia Luo Xiaohan niu Min Chao Pengfei Zhang Luke Yan Polymer Materials&Engineering Department School of Materials Science&EngineeringChang’an UniversityXi’an 710064China Key Laboratory of Road Construction Technology and Equipment MOEChang’an UniversityXi’an 710064China School of Textile Science and Engineering Xi’an Polytechnic UniversityXi’an 710064China

Graphitic carbon nitride(g-C_(3)n_(4))nanosheets have attracted widespread interest in the construction of advanced separation ***,dense stacking and a single functionality have limited the membrane ***,an advanced two-/three-dimensional(2D/3D)g-C_(3)n_(4)/TiO_(2)@MnO_(2) membrane is constructed by intercalating 3D TiO_(2)@MnO_(2) nanostructures into g-C_(3)n_(4) *** 3D flower-like nanostructures broaden the transport channels of the composite *** membrane can effectively separate five oil-in-water(O/W)emulsions,with a maximum flux of 3265.67±15.01 L·m^(-2)·h^(-1)·bar^(-1) and a maximum efficiency of 99.69%±0.45%for toluene-in-water emulsion(T/W).Meanwhile,the TiO_(2)@MnO_(2) acts as an excellent electron acceptor and provides positive spatial separation of electrons–holes(e^(-)–h^(+)).The formation of 2D/3D heterojunctions allows the material with wider light absorption and smaller bandgap(2.10 eV).These photoelectric properties give the membrane good degradation of three different pollutants,with about 100%degradation for methylene blue(MB)and malachite green(MG).The photocatalytic antibacterial efficiency of the membrane is also about 100%.After cyclic experiment,the membrane maintains its original separation and photocatalytic *** remarkable multifunctional and self-cleaning properties of the g-C_(3)n_(4) based membrane represent its potential value for complex wastewater treatment.

关键词： graphitic carbon nitride(g-C_(3)n_(4))based membrane three-dimensional(3D)nanostructures self-cleaning multifunction

High adsorption selectivity of activated carbon and carbon molecular sieve boosting CO_(2)/n_(2) and CH_(4)/n_(2) separation

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Chinese Journal of Chemical Engineering 2024年第3期67卷 282-297页

作者： Siang Chen Wenling Wu Zhaoyang niu Deqi Kong Wenbin Li Zhongli Tang Donghui Zhang The Research Center of Chemical Engineering School of Chemical Engineering and TechnologyTianjin UniversityTianjin 300072China

Flue gas and coal bed methane are two important sources of greenhouse *** swing adsorption process has a wide range of application in the field of gas separation,and the selection of adsorbent is *** this regard,in order to assess the better adsorbent for separating CO_(2) from flue gas and CH_(4) from coal bed methane,adsorption isotherms of CO_(2),CH_(4) and n_(2) on activated carbon and carbon molecular sieve are measured at 303.15,318.15 and 333.15 K,and up to 250 *** experimental data fit better with Langmuir 2 compared to Langmuir 3 and Langmuir-Freundlich models,and Clausius-Clapeyron equation was used to calculate the isosteric *** the order of the adsorbed amount and the adsorption heat on the two adsorbents are CO_(2)>CH_(4)>n_(2).The adsorption kinetics are calculated by the pseudo-first kinetic model,and the order of adsorption rates on activated carbon is n_(2)-CH_(4)>CO_(2),while on carbon molecular sieve,it is CO_(2)-n_(2)>CH_(4).It is shown that relative molecular mass and adsorption heat are the primary effect on kinetics for activated carbon,while kinetic diameter is the main resistance factor for carbon molecular ***,the adsorption selectivity of CH_(4)/n_(2) and CO_(2)/n_(2) were estimated with the ideal adsorption solution theory,and carbon molecular sieve performed best at 318.15 K for both CO_(2) and CH_(4) *** study suggested that activated carbon is a better choice for separating flue gas and carbon molecular sieve can be a strong candidate for separating coal bed methane.

关键词： Activated carbon Carbon molecular sieve Adsorbent evaluation Adsorption equilibrium and kinetics Heat of adsorption Selectivity

Synthesis of crystalline g-C_(3)n_(4) with rock/molten salts for efficient photocatalysis and piezocatalysis

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Green Energy & Environment 2024年第5期9卷 890-898页

作者： Tingting Xu Jung Hur Ping niu Shulan Wang Sangwook Lee Sang-Eun Chun Li Li Department of Chemistry College of ScienceNortheastern UniversityShenyang110819China State Key Laboratory of Rolling and Automation Northeastern UniversityShenyang110819China School of Metallurgy Northeastern UniversityShenyang110819China School of Materials Science and Engineering Kyungpook National UniversityDaegu41566Republic of Korea School of Industrial Technology Advances Kyungpook National UniversityDaegu41566Republic of Korea

Graphitic carbon nitride(g-C_(3)n_(4))is emerging as a promising visible-light photocatalyst while the low crystallinity with sluggish charge separation/migration dynamics signiﬁcantly restricts its practical ***,synthesizing highly crystalline g-C_(3)n_(4) with sufﬁcient surface activities still remains ***,different from using alkali molten salts which is commonly reported,we propose an approach for synthesis of highly crystalline g-C_(3)n_(4) with FeCl3/KCl rock/molten mixed *** rock salt can serve as the structure-directing template while molten salt provides the required liquid medium for ***,the synthesized photocatalyst showed further enhanced crystallinity and improved surface area along with high p/p*excitation compared with crystalline C_(3)n_(4) prepared from conventional molten-salt *** catalytically advantageous features lead to its superior photocatalytic and piezocatalytic activities with a high reactivity for overall water splitting that is not commonly reported for C_(3)n_(4).This work provides an effective strategy for structural optimization of organic semiconductor based materials and may inspire new ideas for the design of advanced photocatalysts.

关键词： High crystallinity Carbon nitride Photocatalysis Piezocatalysis Overall water splitting

■-dressing Method for the Coupled Two-component Kundu-Eckhaus Equations

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Acta Mathematicae Applicatae Sinica 2024年

作者： Zhen-jie niu Biao LI School of Mathematics and Statistics Ningbo University

In this paper,■-dressing method based on a local 3×3 matrix ■-problem with non-normalization boundary conditions is used to investigate coupled two-component Kundu-Eckhaus ***,we propose a new compatible system with singular dispersion relation,that is time spectral problem and spatial spectral problem of coupled two-component Kundu-Eckhaus equations via constraint ***,we derive a hierarchy of nonlinear evolution equations by introducing a recursive *** last,by solving constraint matrixes,a spectral transform matrix is given which is sufficiently important for finding soliton solutions of potential function,and we obtain n-soliton solutions of coupled two-component Kundu-Eckhaus equations.

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Subtropical forest macro-decomposers rapidly transfer litter carbon and nitrogen into soil mineral-associated organic matter

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Forest Ecosystems 2024年第2期11卷 131-139页

作者： Guoxiang niu Tao Liu Zhen Zhao Xuebing Zhang Huiling Guan Xiaoxiang He Xiankai Lu national Engineering Laboratory for Applied Technology of Forestry and Ecology in South China Central South University of Forestry and TechnologyChangsha410004China Lushan Botanical Garden Chinese Academy of SciencesJiujiang332900China Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems South China Botanical GardenChinese Academy of SciencesGuangzhou510650China Section of Microbial Ecology Department of BiologyLund UniversityLund22362Sweden Lutou national Station for Scientific Observation and Research of Forest Ecosystem in Hunan Province Yueyang414000China

Background:Forest soils in tropical and subtropical areas store a significant amount of *** framework to assess soil organic matter(SOM)dynamics under evolving global conditions suggest that dividing bulk SOM into particulate and mineral-associated organic matter(POM ***)is a promising method for identifying how SOM contributes to reducing global *** macrofauna,earthworms,and millipedes have been found to play an important role in facilitating SOM ***,how these two co-existing macrofaunae impac the litter decomposition process and directly impact the formation of POM and MAOM remains ***:Here,we set up a microcosm experiment,which consisted of 20 microcosms with four treatments earthworm and litter addition(E),millipedes and litter addition(M),earthworm,millipedes,and litter addition(E+M),and control(only litter addition)in five *** soil and litter were sterilized prior to beginning the incubation experiment to remove any existing *** incubating the samples for 42 days,the litte properties(mass,C,and n contents),soil physicochemical properties,as well as the C and n contents,and POM and MAOM^(13)C abundance in the 0–5 and 5–10 cm soil layers were ***,the relative influences o soil physicochemical and microbial properties on the distribution of C and n in the soil fractions were analyzed Results:The litter mass,C,and n associated with all four treatments significantly decreased after incubation especially under treatment E+M(litter mass:-58.8%,litter C:-57.0%,litter n:-75.1%,respectively),while earthworm biomass significantly decreased under treatment *** or millipede addition alone showed no significant effects on the organic carbon(OC)and total nitrogen(Tn)content in the POM fraction,but join addition of both significantly increased OC and Tn regardless of soil ***,all three macrofauna treatments increased the OC and Tn content and decreased the^(13)C abundance

关键词： Tropical and subtropical forest Soil organic matter fractions Earthworm Millipedes Litter decomposition

Insight into the experiment and extraction mechanism for separating carbazole from anthracene oil with quaternary ammonium-based deep eutectic solvents

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Chinese Journal of Chemical Engineering 2024年第1期65卷 188-199页

作者： Xudong Zhang Yanhua Liu Jun Shen Yugao Wang Gang Liu Yanxia niu Qingtao Sheng College of Chemical Engineering and Technology Taiyuan University of TechnologyTaiyuan 030024China

Carbazole is an irreplaceable basic organic chemical raw material and intermediate in *** separation of carbazole from anthracene oil by environmental benign solvents is important but still a challenge in chemical *** eutectic solvents (DESs) as a sustainable green separation solvent have been proposed for the separation of carbazole from model anthracene *** this research,three quaternary ammonium-based DESs were prepared using ethylene glycol (EG) as hydrogen bond donor and tetrabutylammonium chloride (TBAC),tetrabutylammonium bromide or choline chloride as hydrogen bond *** explore their extraction performance of carbazole,the conductor-like screening model for real solvents (COSMO-RS) model was used to predict the activity coefficient at infinite dilution (γ^(∞)) of carbazole in DESs,and the result indicated TBAC:EG (1:2) had the stronger extraction ability for carbazole due to the higher capacity at infinite dilution (C^(∞)) ***,the separation performance of these three DESs was evaluated by experiments,and the experimental results were in good agreement with the COSMO-RS prediction *** TBAC:EG (1:2) was determined as the most promising ***,the extraction conditions of TBAC:EG (1:2) were optimized,and the extraction efficiency,distribution coefficient and selectivity of carbazole could reach up to 85.74%,30.18 and 66.10%,***,the TBAC:EG (1:2) could be recycled by using environmentally friendly water as *** addition,the separation performance of TBAC:EG (1:2) was also evaluated by real crude anthracene,the carbazole was obtained with purity and yield of 85.32%,60.27%,***,the extraction mechanism was elucidated byσ-profiles and interaction energy *** calculation results showed that the main driving force for the extraction process was the hydrogen bonding ((n–H...Cl) and van der Waals interactions (C–H...O and C–H...π),which correspondin

关键词： Carbazole Model anthracene oil Deep eutectic solvents COSMO-RS Extraction mechanism

Constructing long-cycling crystalline C_(3)n_(4)-based carbonaceous anodes for sodium-ion battery via n configuration control

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Carbon Energy 2024年第1期6卷 159-171页

作者： Ying Wang Hongguan Li Shuanlong Di Boyin Zhai Ping niu Antonios Kelarakis Shulan Wang Li Li School of Metallurgy Northeastern UniversityShenyangLiaoningChina State Key Laboratory of Rolling and Automation Northeastern UniversityShenyangLiaoningChina Department of Chemistry College of ScienceNortheastern UniversityShenyangLiaoningChina School of natural Sciences UCLan Research Centre for Smart MaterialsUniversity of Central LancashirePrestonUK Foshan Graduate School of Innovation Northeastern UniversityFoshanGuangdongChina

Carbon nitrides with two-dimensional layered structures and high theoretical capacities are attractive as anode materials for sodium-ion batteries while their low crystallinity and insufficient structural stability strongly restrict their practical *** carbon nitrides with conductive carbon may relieve these ***,little is known about the influence of nitrogen(n)configurations on the interactions between carbon and C_(3)n_(4),which is fundamentally critical for guiding the precise design of advanced C_(3)n_(4)-related ***,highly crystalline C_(3)n_(4)(poly(triazine imide),PTI)based all-carbon composites were developed by molten salt *** importantly,the vital role of pyrrolic-n for enhancing charge transfer and boosting na+storage of C_(3)n_(4)-based composites,which was confirmed by both theoretical and experimental evidence,was spot-highlighted for the first *** elaborately controlling the salt composition,the composite with high pyrrolic-n and minimized graphitic-n content was *** from the formation of highly crystalline PTI and electrochemically favorable pyrrolic-n configurations,the composite delivered an unusual reverse growth and record-level cycling stability even after 5000 cycles along with high reversible capacity and outstanding full-cell capacity *** work broadens the energy storage applications of C_(3)n_(4) and provides new prospects for the design of advanced all-carbon electrodes.

关键词： anode highly crystalline C_(3)n_(4) n configuration sodium-ion batteries ultra-long cyclic stability