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Environmental impacts on the distribution of microbial tetraether lipids in Chinese lakes with contrasting pH: Implications for lacustrine paleoenvironmental reconstructions

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Science China Earth Sciences 2016年第2期59卷 939-950页

作者： DAng Xinyue XUE JianTao y.ng Huan xie ShuCheng School of Earth Sciences China University of Geosciences State Key Laboratory of Biogeology and Environmental Geology China University of Geosciences

Glycerol dialkyl glycerol tetraethers(GDGTs) in lake sediments are useful biomarkers for the continental paleoclimatic reconstruction. However, the environmental controls on the distribution of these compounds, in particular the 6-methyl isomers of bacterial branched GDGTs(bGDGTs), in the lakes with contrasting pH, are still unknown, hindering their application for paleo-reconstructions. Here, we investigated the environmental impacts on the distribution of GDGTs in 17 alkaline lakes and 1 acid lake in China. It was found that the dissolved oxygen content in water column may have an impact on the distribution of archaeal isoprenoid GDGTs(iGDGTs) by causing the change in archaeal communities. The ratio of GDGT-0/crenarchaeol increases with decreasing oxygen content, indicating that the relative abundance of anaerobic methanogenic archaea or Miscellaneous Crenarchaeotic Group(MCG) vs. aerobic Thaumarchaeota is controlled by the oxygen content dissolved in water of these lakes. Thaumarchaeota are likely to contribute only a small proportion of iGDGTs in the relatively oxygen-depleted lakes, and thus TEX_(86) is not suitable for the reconstruction of the surface temperature of these lakes. The abundance ratio of iGDGTs to bGDGTs(R_(i/b)) appears to show no relationship with water pH in all the lakes, but exhibits a significant positive correlation with the water depth of the acid Lake Qinghai in Tengchong. As expected, the methylation degree of bGDGTs(MBT′) was found to correlate with both mean annual air temperature(MAT) and water pH, and the cyclization degree of bGDGTs(CBT) correlates only with water pH in these lakes. However, the MBT′_(5ME), an index to measure the methylation degree of 5-methyl bGDGTs, exhibits no relationship with MAT, whereas MBT′_(6ME), the methylation degree of 6-methyl bGDGTs, was found to correlate significantly with MAT. This is opposite to the situation observed in the global soils, pointing to a different adaptation of b GDGT-producing ba

关键词： GDGTs Lake 6-methyl bGDGTs pH IR

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Leakage Proof,Flame-Retardant,and Electromagnetic Shield Wood Morphology Genetic Composite Phase Change Materials for Solar Thermal Energy Harvesting

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Nano-Micro Letters 2024年第10期16卷 99-120页

作者： yuhui Chen y.ng Meng Jiangyu Zhang yuhui xie Hua Guo Mukun He Xuetao Shi yi Mei Xinxin Sheng Delong xie yunnan Provincial Key Laboratory of Energy Saving in Phosphorus Chemical Engineering and New Phosphorus Materials The International Joint Laboratory for Sustainable Polymers of Yunnan ProvinceThe Higher Educational Key Laboratory for Phosphorus Chemical Engineering of Yunnan ProvinceFaculty of Chemical EngineeringKunming University of Science and TechnologyKunming 650500People's Republic of China Guangdong Provincial Key Laboratory of Functional Soft Condensed Matter School of Materials and EnergyGuangdong University of TechnologyGuangzhou 510006People's Republic of China Shaanxi Key Laboratory of Macromolecular Science and Technology School of Chemistry and Chemical EngineeringNorthwestern Polytechnical UniversityXi'anShaanxi 710072People's Republic of China

Phase change materials(PCMs)offer a promising solution to address the challenges posed by intermittency and fluctuations in solar thermal ***,for organic solid-liquid PCMs,issues such as leakage,low thermal conductivity,lack of efficient solar-thermal media,and flamma-bility have constrained their broad ***,we present an innova-tive class of versatile composite phase change materials(CPCMs)developed through a facile and environmentally friendly synthesis approach,leveraging the inherent anisotropy and unidirectional porosity of wood aerogel(nanowood)to support polyethylene glycol(PEG).The wood modification process involves the incorporation of phytic acid(PA)and MXene hybrid structure through an evaporation-induced assembly method,which could impart non-leaking PEG filling while concurrently facilitating thermal conduction,light absorption,and ***,the as-prepared wood-based CPCMs showcase enhanced thermal conductivity(0.82 W m^(-1)K^(-1),about 4.6 times than PEG)as well as high latent heat of 135.5 kJ kg^(-1)(91.5%encapsula-tion)with thermal durability and stability throughout at least 200 heating and cooling cycles,featuring dramatic solar-thermal conversion efficiency up to 98.58%.In addition,with the synergistic effect of phytic acid and MXene,the flame-retardant performance of the CPCMs has been significantly enhanced,showing a self-extinguishing ***,the excellent electromagnetic shielding of 44.45 dB was endowed to the CPCMs,relieving contemporary health hazards associated with electromagnetic ***,we capitalize on the exquisite wood cell structure with unidirectional transport inherent in the development of multifunctional CPCMs,showcasing the operational principle through a proof-of-concept prototype system.

关键词： Wood PCMs MXene Solar thermal storage and conversion Flame-retardant Electromagnetic shielding

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Local Discontinuous Galerkin Methods for the abcd Nonlinear Boussinesq System

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Communications on Applied Mathematics and Computation 2022年第2期4卷 381-416页

作者： Jiawei Sun Shusen xie yulong Xing Department of Mathematics The Ohio State UniversityColumbusOH 43210USA School of Mathematical Sciences Ocean University of ChinaQingdao 266100ShandongChina

Boussinesq type equations have been widely studied to model the surface water *** this paper,we consider the abcd Boussinesq system which is a family of Boussinesq type equations including many well-known models such as the classical Boussinesq system,the BBM-BBM system,the Bona-Smith system,*** propose local discontinuous Galerkin(LDG)methods,with carefully chosen numerical fluxes,to numerically solve this abcd Boussinesq *** main focus of this paper is to rigorously establish a priori error estimate of the proposed LDG methods for a wide range of the parameters a,b,c,*** experiments are shown to test the convergence rates,and to demonstrate that the proposed methods can simulate the head-on collision of traveling wave and finite time blow-up behavior well.

关键词： Local discontinuous Galerkin methods Boussinesq equations Coupled BBM equations Error estimate Numerical fluxes Head-on collision

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Hyper-crosslinked Conjugated Microporous Polymers with Increased Micropores Promotes Confining Polymerization for Electromagnetic Absorption Application

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Chinese Journal of Polymer Science 2023年第8期41卷 1305-1316,I0011页

作者： Hao Chen Fang-yuan Chu Hai-yan Zhuang Lu Wang Zhi-Min ye Wei Dong Zhi-Peng xie A-Ming xie School of Mechanical Engineering Nanjing University of Science&TechnologyNanjing 210094China State Key Laboratory for Marine Corrosion and Protection Luoyang Ship Material Research Institute(LSMRI)Xiamen 361100China School of Chemistry and Chemical Engineering Nanjing University of Science&TechnologyNanjing 210094China

Conjugated microporous polymers have excellent skeleton structures but poor electrical conductivity limits their applications in microwave *** solve this problem,a strategy of molecular expansion and confining polymerization is proposed in this work to synthesize conductive hyper-crosslinked conjugated microporous *** topology of the conjugated microporous polymer is changed into a three-dimensional skeleton structure with high specific surface area by using molecular expansion technique,and the controlled growth of polypyrrole in the channel constructs a unique network *** balance of excellent composite backbone structure,proper conductivity,attenuation capability and impedance matching enable the material to exhibit electromagnetic wave absorption *** a result,with low filler loading of 10 wt%,a strongest reflection loss of-52.68 d B and a maximum effective bandwidth of 5.76 ***,CST simulations of the radar scattering cross section have been carried out to verify the excellent material *** study provides new concepts for new conductive polymers and broadens the application of hyper-crosslinked conjugated microporous polymer in the field of electromagnetic wave absorption.

关键词： Hyper-crosslinked conjugated microporous polymer Electromagnetic wave absorbing Molecular expansion Polypyrrole

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Microstructure and properties of coarse-grained WC-10Co cemented carbides with different carbon contents during heat treatments

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Rare Metals 2024年第4期43卷 1786-1792页

作者： yuan-Feng xie Xing-Cheng xie Zhong-Wu Li Rui-Jun Cao Zhong-Kun Lin Qing Li Chen-Guang Lin Powder Metallurgy and Special Materials Research Department General Research Institute for Nonferrous MetalsBeijing100088China

The effects of cryogenic treatment(CT)and tempering-cryogenic treatment(TCT)on the microstructure and properties of coarse-grained WC-10Co cemented carbides with different carbon contents were *** binder phase,WC mean grain sizes,W solubility in the binder,relative magnetic s aturation,densities,hardness,wear resistance and second phase precipitation of cemented carbides with different heat treatments were *** results show that there are significant changes of microstructure and properties in the samples with CT and TCT,especially due to the precipitation of metastable nanoparticles W_(x)Co_(y)C_(z) in the binder during the heat treatments of CT and *** the simultaneous combination of microstructure and nanoparticle-reinforced binder,a dramatically improved combination of hardness and wear resistance of the samples after TCT has been achieved.

关键词： Cryogenic treatment Tempering Coarsegrained cemented carbide Carbon content Nanoparticlereinforced binder

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Modularity-like objective function in annotated networks

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Frontiers of physics 2017年第6期12卷 109-113页

作者： Jia-Rong xie Bing-Hong Wang Department of Modern Physics University of Science and Technology of China Hefei 230026 China

We ascertain the modularity-like objective function whose optimization is equivalent to the maximum likelihood in annotated networks. We demonstrate that the modularity-like objective function is a lin- ear combination of modularity and conditional entropy. In contrast with statistical inference methods, in our method, the influence of the metadata is adjustable; when its influence is strong enough, the metadata can be recovered. Conversely, when it is weak, the detection may correspond to another partition. Between the two, there is a transition. This paper provides a concept for expanding the scope of modularity methods.

关键词： community structure annotated networks modularity objective function

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REDUCTION BEHAVIOR OF IRON ORE PELLETS CONTAINIngCARBON UNDER NON-ISOTHERMAL CONDITION

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Acta Metallurgica Sinica(English Letters) 2000年第5期13卷 1059-1067页

作者： X.M.y.ng y.S.xie D.G.Wang D.B.Huang T.J.y.ng L.T.Kong Institute of Chemical Metallurgy The Chinese Academy of Sciences Beijing 100080China University of Science and Technology Beijing Beijing 100083China

The reduction behavior of iron ore pellets containing carbon under non-isothermal condition in the temperature range from 573 to 1373 K was investigated in a laboratory scale setup. The test results show that carbon content has no obvious effect on reduction degree of composite pellets (C/O mole ratio=1.0) by CO in the temperature range from 573 to 1373 K under linear temperature-rising program; reduction degree of iron ore pellets containing carbon is large in 90%CO-10%CO2 mixture than that of in 100%CO atmosphere or in 80%CO-20%CO2 mixture; the s type temperature-rising program has a better effect than that of linear one in increasing the reduction degree; and reduction degree of slower linear temperature-rising program is greater than that of faster one, but the final reduction degrees, i.e., those at the highest temperature are about the same for various CO partial pressures or temperature-rising programs. The kinetic analysis also shows that the reduction of iron ore-carbon composite pellets by CO or CO-CO2 mixture under non-isothermal condition should be controlled by surface reaction, and the apparent reduction activation energy changes with the reduction progress under various test conditions.

关键词： iron ore pellet containing carbon reduction behavior kinetics activation energy non-isothermal

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RESEARCH AND SIMULATION OF THE INFLUENCE OF THREE-AXIAL COMPACTION ON POWDER METALLURGIC PRODUCT PROPERTIES

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Acta Metallurgica Sinica(English Letters) 2008年第2期21卷 116-124页

作者： D. G. Wang y.C. Wu M.H. Jiao T.xie J.W. yu K G. Fin School of Material and Engineering Hefei University of Technology Hefei 230009 China Institute of Tribology Hefei University of Technology Hefei 230009 China

The warm powder compaction process is simulated by the finite element analysis software, MSCJMARC. The thermal mechanically coupled analysis method is applied on the basis of the updated Lagrangian Method, to simulate the warm powder compaction process. The warm powder compaction process is simulated, and the influence of friction condition and pressing styles are researched on the density of powder green and the mechanics behavior at certain temperature. The results indicate that for cylindrical compacts, with the improvement of the friction condition, the uniformity of distribution of green relative density is largely improved, the pressing force and stress decrease, and the nonconforming pressing processes influence the distribution of green density to some degree. The status of stress distribution of the process that punches firstly press and die finally press is different from the other three processes, and presents the figure of ＇flume ＇.

关键词： Density FEM Property Three-axial compaction

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Multiplicative Mappings of Rings

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Acta Mathematica Sinica,English Series 2006年第4期22卷 1017-1020页

作者： Fang yan LU Jin Hai xie Department of Mathematics Suzhou University Suzhou 215006 P. R. China

Let R and F be arbitrary associative rings. A mapping φ of R onto F is called a multiplicative isomorphism if φ is bijective and satisfies φ（xy） = φ（x）φ（y） for all x, y ∈ R. In this short note, we establish a condition on R, in the case where R may not contain any non-zero idempotents, that assures that φ is additive, which generalizes the famous Martindale＇s result. As an application, we show that under a mild assumption every multiplicative isomorphism from the radical of a nest algebra onto an arbitrary ring is additive.

关键词： Multiplicative isomorphisms Additivity Idempotents

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Glass Forming Ability and Crystallization Kinetics of Cu-Zr-Al-(y,Ag)Amorphous Alloy

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Journal of Wuhan University of Technology(Materials Science) 2018年第4期33卷 938-945页

作者：岳丽杰 LIU yali xie Kun College of Material Science and Engineering Shandong University of Science and TechnologyQingdao 266590China State Key Laboratory of Mining Disaster Prevention and Control Co-founded by Shandong Province and the Ministry of Science and Technology Shandong University of Science and TechnologyQingdao 266590China

Cu-Zr-Al-（y, Ag） amorphous alloy ribbons of Cu_（50）Zr_（42）Al_8, Cu_（46）Zr_（47-x）Al_7y_x（x=2, 5）, Cu_（43）Zr_（42）Al_8Ag_7, and Cu_（43）Zr_（42）Al_8Ag_5y_2 were prepared using the single roller melt-spinning method. The glass forming ability and non-isothermal crystallization behavior of the amorphous alloys were investigated by means of X-ray diffraction（XRD） and differential scanning calorimetry（DSC） in a continuous heating mode. The experimental results show that the glass forming ability and thermal stability of Cu-Zr-Al amorphous alloys are improved by adding minor amounts of y and Ag, and the effect of Ag on the glass forming ability is more significant than that of y. Compared to the Cu_（50）Zr_（42）Al_8 alloy, the width of the supercooled liquid region of the Cu_（46）Zr_（47-x）Al_7y_x（x =2 and 5） alloys increased by 19 K and 30 K, respectively. The reduced glass transition temperature（Trg） and the parameter γ of the two alloys enhanced separately. Compared to the Cu_（50）Zr_（42）Al_8 alloy, the Trg and γ values of both Cu_（43）Zr_（42）Al_8Ag_7 and Cu_（43）Zr_（42）Al_8Ag_5y_2 alloys enhanced noticeably up to 0.619, 0.417, and 0.609, 0.412, respectively. The crystallization activation energies of the amorphous alloys calculated by the Kissinger and Flynn Wall Ozawa equations increased with the addition of minor y and Ag into the Cu_（50）Zr_（42）Al_8 alloy. The addition of y and Ag significantly improved the thermal stability of the Cu_（50）Zr_（42）Al_8 amorphous alloy.

关键词： amorphous alloy yttrium micro-alloy.ng non-isothermal crystallization

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