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Flame Structure of Methane and Kerosene Combustion with a Compact Concave Flame-Holder using the LES-pdf Method

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Journal of Thermal Science 2024年第1期33卷 222-234页

作者： WANG Fang WANG Yunfan wei Guanyi LIU Denghuan JIN Jie JONES p.William School of Energy and power Engineering Beihang UniversityBeijingBeijing 100191China Department of Mechanical Engineering Imperial College LondonLondon SW72AZUK

Compact flame-holders for afterburners are an increasing requirement for modern aero ***,flame-holder design is non-trivial since high inlet temperatures,velocities,and elaborate structures induce complex turbulence,combustion,and spray coupling in modern *** this work,the LES-pdf and stochastic fields-Lagrangian particle spray methods are used to investigate methane and aviation kerosene combustion structures formed by new-type concave *** flow pattern,combustion mode,and flame structure of gaseous and liquid fuel around a concave flame-holder are analyzed,discussed,and compared with experimental *** reveal that the flame stability of a concave flame-holder is better than that of the non-concave ***,when using liquid fuel,the concave flame-holder forms a stable and compact *** results suggest concave flame-holders are a promising design for compact afterburners.

关键词： concave structure flame-holder LES-pdf spray combustion flame structure AECSC

Diet and monensin influence the temporal dynamics of the rumen microbiome in stocker and finishing cattle

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Journal of Animal Science and Biotechnology 2024年第2期15卷 733-748页

作者： Jianmin Chai Caleb p.weiss paul A.Beck wei Zhao Ying Li Jiangchao Zhao Guangdong provincial Key Laboratory of Animal Molecular Design and precise Breeding College of Life Science and EngineeringFoshan UniversityFoshanChina Division of Agriculture Department of Animal ScienceUniversity of ArkansasFayettevilleARUSA Department of Animal and Food Sciences Oklahoma State UniversityStillwaterOKUSA Institute of Feed research of Chinese Academy of Agricultural Sciences Key Laboratory of Feed Biotechnology of the Ministry of Agriculture and Rural AffairsBeijing 100193China

Background Stocker cattle diet and management influence beef cattle performance during the finishing stage,but knowledge of the dynamics of the rumen microbiome associated with the host are lacking.A longitudinal study was conducted to determine how the feeding strategy from the stocker to the finishing stages of production affects the temporal dynamics of rumen *** the stocker phase,either dry hay or wheat pasture were provided,and three levels of monensin were *** calves were then transported to a feedlot and received similar finishing diets with or without *** microbial samples were collected on d 0,28,85 during the stocker stage(S0,S28 and S85)and d 0,14,28,56,30 d before slaughter and the end of the trial during the finishing stage(F0,F14,F28,F56,pre-Ba,and Final).The V4 region of the bacterial 16S rrNA gene of 263 rumen samples was *** Higher alpha diversity,including the number of observed bacterial features and the Shannon index,was observed in the stocker phase compared to the finishing *** bacterial amplicon sequence variants(ASVs)differentiating different sampling time points were *** treatments during the stocker stage temporally impact the dynamics of rumen *** example,shared bacteria,including Bacteroidales(ASV19)and Streptococcus infantarius(ASV94),were significantly higher in hay rumen on S28,S85,and F0,while Bacteroidaceae(ASV11)and Limivicinus(ASV15)were more abundant in *** affected rumen microbial composition at a specific *** to feedlot significantly influenced microbiome structure and diversity in hay-fed *** taxa associated with body weight were classified,and core microbiotas interacted with each other during the *** In summary,the temporal dynamics of the rumen microbiome in cattle at the stocker and finishing stage are influenced by multiple factors of the feeding *** at the stocker phase may t

关键词： Beef cattle Diet Feedlot phase Monensin Next-generation sequencing rumen microbiota Stocker

Orbital pacing and secular evolution of lake-level changes reconstructed by sedimentary noise modeling during the Early Jurassic icehouses-(super)greenhouses

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Science China Earth Sciences 2024年第1期67卷 252-267页

作者： Meng LI Xin LI Stephen p.HESSELBO Mingjie LI Wenjin LIU wei WU Jienan pAN ruizhen GAO School of resources and Environment Henan Polytechnic UniversityJiaozuo 454000China Camborne School of Mines and Environment and Sustainability Institute University of ExeterPenryn TR109FEUnited Kingdom Qinghai No.105 Coal Geological Exploration Team Xining 810000China

Lake-level changes can significantly affect paleoenvironmental evolution,resource occurrence,terrestrial carbon budget,and biodiversity in continental *** is one of the most critical factors controlling lake-level *** of the Early Jurassic has been evidenced by oscillating icehouses to(super)greenhouses with interrupted intermittent extreme climatic events(hyperthermal and cooling),e.g.,the Toarcian oceanic anoxic event(~183 Ma)and the late pliensbachian cooling event(~185 Ma).Lake-level evolution and hydrologic cycling on Earth’s surface during the Early Jurassic icehouses-to-(super)greenhouses are thus far poorly understood due to a lack of continuous high-resolution nonmarine *** we present a super-long nonmarine lake level record for this pivotal interval from the early pliensbachian to Toarcian by sedimentary noise modeling,and construct a 16.7-Myr-long astronomical time scale(174.2 Ma to 190.9 Ma)based on cyclostratigraphy analysis of rock color datasets(CIE b*)of the Qaidam *** results document lake-level oscillations on a 5-to 10-million-year(Myr)scale which shows a pronounced correlation with long-term climate variation and extreme climatic events,and 1-to 2.5-Myr-scale lake-level changes that are prominently paced by the 2.4-Myr long-eccentricity forcing and the 1.2-Myr obliquity *** the pliensbachian Stage,the 1.2-Myr-scale lake-level changes are in phase with the coeval sealevel *** forced growth and decay of the ephemeral or permanent ice sheets in polar regions are interpreted to control the synchronous ups-and-downs of continental lake level and global sea ***,during the Toarcian ice-free greenhouses to(super)greenhouses,the 1.2-Myr-scale lake-level variations show an anti-phase relationship with global sea level,indicating a‘seesaw’interaction between continental reservoirs(lakes and groundwater)and global *** 2.4-Myr longeccentricity cycles mainly regulate variation

关键词： Milankovitch cycles Orbital forcing Sedimentary noise model Lake level Continental basins

A novel cascaded H-bridge photovoltaic inverter with flexible arc suppression function

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Global Energy Interconnection 2024年第4期7卷 513-527页

作者： Junyi Tang wei Gao College of Electrical Engineering and Automation Fuzhou UniversityFuzhou 350108P.R.China

This paper presents a novel approach that simultaneously enables photovoltaic(pV)inversion and flexible arc suppression during single-phase grounding *** compensate for ground currents through an arc-elimination function,while outputting a pV direct current(DC)power *** method effectively reduces the residual grounding *** reduce the dependence of the arc-suppression performance on accurate compensation current-injection models,an adaptive fuzzy neural network imitating a sliding mode controller was *** online adaptive adjustment law for network parameters was developed,based on the Lyapunov stability theorem,to improve the robustness of the inverter to fault and connection ***,a new arc-suppression control exit strategy is proposed to allow a zerosequence voltage amplitude to quickly and smoothly track a target value by controlling the nonlinear decrease in current and reducing the regulation *** results showed that the proposed method can effectively achieve fast arc suppression and reduce the fault impact current in single-phase grounding *** to other methods,the proposed method can generate a lower residual grounding current and maintain good arc-suppression performance under different transition resistances and fault locations.

关键词： photovoltaic inverter Flexible arc suppression Adaptive control Fuzzy neural network Sliding mode control Exit strategy

Two Applications of the ■■-Hodge Theory

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Chinese Annals of Mathematics,Series B 2024年第1期45卷 137-150页

作者： Dingchang wei Shengmao ZHU Center of Mathematical Sciences Zhejiang UniversityHangzhou 310027China Department of Mathematics Zhejiang Normal UniversityJinhua 321004ZhejiangChina

Using Hodge theory and Banach fixed point theorem,Liu and Zhu developed a global method to deal with various problems in deformation *** this note,the authors generalize Liu-Zhu's method to treat two deformation problems for non-Kahler *** apply the ■■-Hodge theory to construct a deformation formula for(p,q)-forms of compact complex manifold under deformations,which can be used to study the Hodge number of complex manifold under *** the second part of this note,by using the ■■-Hodge theory,they provide a simple proof of the unobstructed deformation theorem for the non-Kahler Calabi-Yau ■■-manifolds.

关键词： Complex structures Deformations (p,q)-Forms Non-Kahler Calabi-Yaumanifolds

Nutrient transport following water transfer through the world's largest water diversion channel

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Journal of Environmental Sciences 2024年第1期135卷 703-714页

作者： Yuanhui Cheng Hong Zhang wei Yin State Key Laboratory of Environmental Aquatic Chemistry Research Center for Eco-Environmental SciencesChinese Academy of SciencesBeijing 100085 China Changjiang Water resources protection Institute Wuhan 430051China University of Chinese Academy of Sciences Beijing 100049China

Nutrient levels in the artificial channel constructed for the Middle route project are significant indicators of water quality safety and aquatic ecological integrity for this large,interbasin ***,the distribution and transport of nutrients along the channel were poorly *** on a time-series dataset as well as mass balance and material flow analysis methods,the water and nutrient transport fluxes in the Middle route of the South-to-North Water Diversion project were identified in this *** results indicate that the nutrient concentrations varied considerably with time,but there was no significant difference among the 30 stations of the main *** temperature difference was the major factor in the large fluctuations of water quality indicators over *** nutrient loadings varied with the water volume outputs from the main channel to the waterreceiving *** deposition was an important source of nutrients in the main channel,accounting for 9.13%,20.6%,and 0.635%of the nitrogen,phosphorus,and sulfur input from the Danjiangkou reservoir,*** 2021,a net accumulation of 988 tons of N,29 tons of p,and 2,540 tons of S,respectively,were present in the main *** increase of these external and internal nutrient loadings would cause water quality fluctuation and deterioration in some local sections of the main *** study quantified the spatial and temporal patterns of nutrient transport in the Middle route and revealed the ecological effects on the aquatic environment,assisting authorities on the project to develop effective water conservation strategies.

关键词： Nutrient transport Spatiotemporal patterns The Middle route The South-to-North Diversion project Hydro-ecological effects Water-receiving cities

Enhanced thermoelectric and mechanical properties of Bi_(0.5)Sb_(1.5)Te_(3) alloy with dispersed yttrium oxide ceramic nanoparticles

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rare Metals 2024年第4期43卷 1758-1768页

作者： Cun-Cheng Li Ming-wei Zhang Ji-Wu Xin Lei wei Wen-Yu Zhao School of Materials Science and Engineering Shandong University of TechnologyZibo255000China School of Electrical and Electronic Engineering Nanyang Technological UniversitySingapore639798Singapore State Key Laboratory of Advanced Technology for Materials Synthesis and processing Wuhan University of TechnologyWuhan430070China

reducing thermal conductivity while avoiding adverse interfacial reactions during sintering is crucial for improving the thermoelectric performance of Bi_(2)Te_(3)based *** ceramic nanoparticles are good candidates for achieving this *** this study,we designed and prepared a series of p-type Bi_(0.5)Sb_(1.5)Te_(3)nanocomposites decorated with Y_(2)O_(3)ceramic nanoparticles via ball-milling dispersion and spark-plasma *** to the chemical stability of the ceramics,no traces of atomic doping or interfacial reactions were *** measurements revealed that the Y_(2)O_(3)nanoparticles distributed along the grain boundaries acted as energy-dependent carrier-filtering centers to improve the scattering parameter and Seebeck coefficient,contributing to the elevated power factor even with a decreased electrical ***,the incorporated Y_(2)O_(3)nanoparticles and various defect structures they induced effectively strengthened the phonon scattering and suppressed the lattice thermal ***,a peak figure of merit(ZT)of 1.23 at 313 K was achieved for 0.4%Y_(2)O_(3)/Bi_(0.5)Sb_(1.5)Te_(3),which is 13%higher than that of the *** addition,the Vickers hardness of the composite material was 35%higher than that of the *** study demonstrates the effectiveness of ceramic nanoparticles in synergistic ally improving the thermoelectric and mechanical properties,which may be further extended to other thermoelectric systems.

关键词： Bi_(0.5)Sb_(1.5)Te_3 alloy Y_(2)O_(3) ceramic nanoparticles Microstructures Thermoelectric performance Mechanical properties

Critical role of Ethylene-propylene Block Copolymer in Impact polypropylene Copolymer

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Chinese Journal of polymer Science 2024年第3期42卷 344-351,I0007页

作者： Yu-Hui Tang Na Zhang wei Bao wei Jiang Yuan Lin Zhao-Hui Su State Key Laboratory of polymer physics and Chemistry Changchun Institute of Applied ChemistryChinese Academy of SciencesChangchun 130022China School of Applied Chemistry and Engineering University of Science and Technology of ChinaHefei 230026China

Ethylene-propylene block copolymer(Ebp) is a vital component in impact polypropylene copolymer(IpC), yet its distribution in the multiphase composite material and how it influences the phase structure and the mechanical properties are not well understood. In this work,four IpCs were investigated by atomic force microscopy-infrared(AFM-Ir) to assess the phase compositions in situ, based on which in conjunction with the chain microstructure information obtained ex situ the distributions of the copolymer components were derived for each alloy. For the IpCs whose Ebp comprises long p and long E segments, the Ebp fraction was found to phase separate from the rubber and the pp matrix to form the cores of the disperse particles with the E-p segmented copolymer(Esp). In contrast, in the IpC with Ebp composed of long p and short E segments, the Ebp fraction formed an outer shell for the rubber particles with the cores comprising the Esp alone, and this IpC, containing a lower E comonomer content than its counterpart, exhibited both better impact resistance and higher flexural modulus. These results clarify how the chain structure of Ebp governs the phase morphology in IpC, which in turn impacts the properties of the composite material.

关键词： Impact polypropylene copolymers AFM-Ir Ethylene-propylene block copolymers Core-shell rubber particles

Dynamic Measurement of Intracellular pH Based on Bioluminescent Bacteria

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Chemical research in Chinese Universities 2024年第2期40卷 287-292页

作者： LI Yaohua WANG wei State Key Laboratory of Analytical Chemistry for Life Science School of Chemistry and Chemical EngineeringChemBIC(Chemistry and Biomedicine Innovation Center)Nanjing UniversityNanjing210023P.R.China

Intracellular pH(pHi)is a fundamental indicator of cellular physiological state,regulating cellular state and function,and has important research *** various probes for measuring intracellular pH were available,it is challenging to reflect pHi in real-time and reversible ***,we developed a whole-cell bioluminescent(BL)probe based on wild type BL bacteria,photobacterium phosphoreum(***),to determine and image *** dependence of BL intensity of *** on pH values of culture solutions was *** was found that BL intensity could respond to the change of pH values rapidly and *** further revealed that *** maintained pH homeostasis in the extracellular pH(pHe)within the range of 5.0–7.0,while intracellular pH homeostasis was destroyed at the alkaline *** method opens up the enormous potential of BL bacteria as an alternative to fluorescence for monitoring and imaging pHi.

关键词： Bioluminescence p.phosphoreum Intracellular pH Cell imaging