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Straw addition increases enzyme activities and microbial carbon metabolism activities in bauxite residue

Journal of Environmental Sciences 2024年第1期135卷 332-344页

作者： Hao wu Wei Sun feng Zhu Yifan Jiang Shiwei Huang Johnvie Goloran Shengguo xue School of Minerals Processing and Bioengineering Central South UniversityChangsha 410083China School of Metallurgy and Environment Central South UniversityChangsha 410083China School of Environment and Science Griffith UniversityBrisbaneQLD 4072Australia

Recovery of microbial functions is one of the critical processes in the nutrient cycling of bauxite residue for improving *** is considered to be effective to increase microbial diversity and drive the development of the microbial community,but its effect on microbial carbon metabolism has not been *** present study evaluated the effects of phosphogypsum(PG),straw(SF)and phosphogypsum plus straw(PGSF)on physicochemical properties,enzyme activities,and microbial carbon metabolism activities in bauxite *** 180 days incubation,PG,SF and PGSF treatment significantly reduced the residue pH from 10.85 to 8.64,9.39 and 8.06,*** to CK treatment,SF treatment significantly increased the content of total organic carbon(TOC)and organic carbon fractions(DOC,MBC,EOC,and POC).In addition,straw addition significantly increased glucosidase,cellulose,urease,and alkaline phosphatase by 7.2-9.1 times,5.8-7.1 times,11.1-12.5 times,and 1.1-2.2 times,*** Biolog results showed that straw addition significantly increased microbial metabolic activity(AWCD)and diversity in bauxite *** analysis indicated total nitrogen(TN)and carbon fractions(POC,MBC and DOC)were the most important environmental factors affecting microbial metabolic activity and diversity in bauxite *** findings provided us with a biogeochemical perspective to reveal soil formation in bauxite residue and suggested that nutrient supplement and regulation of salinity-alkalinity benefit the establishment of microbial communities and functions in bauxite residue.

关键词： Bauxite residue Labile organic carbon fractions Enzyme activities Community-level physiological profiles Soil formation in bauxite residue

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Testing fundamental physics with astrophysical transients

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Frontiers of physics 2021年第4期16卷 1-25页

作者： Jun-Jie Wei xue-feng wu Purple Mountain Observatory Chinese Academy of SciencesNanjing 210023China School of Astronomy and Space Sciences University of Science and Technology of ChinaHefei 230026China

Explosive astrophysical transients at cosmological distances can be used to place precision tests of the basic assumptions of relativity theory,such as Lorentz invariance,the photon zero-mass hypothesis,and the weak equivalence principle(WEP).Signatures of Lorentz invariance violations(LIV)include vacuum dispersion and vacuum *** searches for LIV using astrophysical sources such as gamma-ray bursts,active galactic nuclei,and pulsars are *** most direct consequence of a nonzero photon rest mass is a frequency dependence in the velocity of light propagating in vacuum.A detailed representation of how to obtain a combined severe limit on the photon mass using fast radio bursts at different redshifts through the dispersion method is *** accuracy of the WEP has been well tested based on the Shapiro time delay of astrophysical messengers traveling through a gravitational *** caveats of Shapiro delay tests are *** this article,we review and update the status of astrophysical tests of fundamental physics.

关键词： astroparticle physics gravitation astrophysical transients

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Tunable quantum anomalous Hall effects in ferromagnetic van der Waals heterostructures

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National Science Review 2024年第3期11卷 100-107页

作者： feng xue Yusheng Hou Zhe Wang Zhiming Xu Ke He Ruqian wu Yong Xu Wenhui Duan Beijing Academy of Quantum Information Sciences State Key Laboratory of Low Dimensional Quantum Physics Department of Physics Tsinghua University Guangdong Provincial Key Laboratory of Magnetoelectric Physics and Devices Center for Neutron Science and Technology School of Physics Sun Yat-sen University State Key Laboratory of Surface Physics Key Laboratory of Computational Physical Sciences and Department of PhysicsFudan University Frontier Science Center for Quantum Information Department of Physics and Astronomy University of California-Irvine Tencent Quantum Laboratory Tencent Technology(Shenzhen)Co.Ltd RIKEN Center for Emergent Matter Science(CEMS) Institute for Advanced Study Tsinghua University

The quantum anomalous Hall effect（QAHE） has unique advantages in topotronic applications, but it is still challenging to realize the QAHE with tunable magnetic and topological properties for building functional devices. Through systematic first-principles calculations, we predict that the in-plane magnetization induced QAHE with Chern numbers C = ±1 and the out-of-plane magnetization induced QAHE with high Chern numbers C = ±3 can be realized in a single material candidate, which is composed of van der Waals（vdW）coupled Bi and MnBi2Te4monolayers. The switching between different phases of QAHE can be controlled in multiple ways, such as applying strain or（weak） magnetic field or twisting the vdW materials. The prediction of an experimentally available material system hosting robust, highly tunable QAHE will stimulate great research interest in the field. Our work opens a new avenue for the realization of tunable QAHE and provides a practical material platform for the development of topological electronics.

关键词： quantum anomalous Hall effect topological quantum phase transition van der Waals heterostructures tunable Chern number high Chern number

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Enhancing the Circularly Polarized Luminescence of Self-assembled Cyanostilbenes through Extended π-Conjugation

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Chinese Journal of Chemistry 2024年第2期42卷 135-141页

作者： Tongjin Lv Song wu Yu Jin Jianfei Ma Sixun Jiang Yuncong xue feng Wang Key Laboratory of Precision and Intelligent Chemistry Department of Polymer Science and EngineeringUniversity of Science and Technology of ChinaHefeiAnhui 230026China Department of Thoracic Surgery Shanghai Jiao Tong University Affiliated Sixth People's HospitalShanghai 200233China

Chiral supramolecular assembly of π-conjugated luminophores provides a promising avenue for enhancing circularly polarized *** this study,we shed light on the impact of π-conjugation length on circularly polarized luminescent performance of the resulting supramolecular assemblies,by designing a tetra-cyanostilbene monomeric compound alongside two dicyanostilbene control *** cyanostilbene-based compounds possess the ability to form chiral supramolecular polymers in toluene,driven by a synergistic combination of intermolecular hydrogen bonding and π-stacking *** extended π π-aromatic skeleton brings bathochromic-shifted fluorescence and enhanced intermolecular stacking capability for the tetra-cyanostilbene ***,chiral supramolecular assemblies formed by the tetra-cyanostilbene compound demonstrate a remarkable two-fold increase in g_(lum) values relative to the assemblies formed by the dicyanostilbene ***,this study provides valuable insights into the relationship between-conjugation length and the circularly polarized luminescent performance of π-conjugatedsupramolecularassemblies.

关键词： Self-assembly Supramolecular polymer Supramolecular chirality Circularly polarized luminescence Cyanostilbene πInteractions Aggregation Nanostructures

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Achieving a remarkable low-temperature tensile ductility in a high-strength tungsten alloy

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Tungsten 2024年第1期6卷 150-161页

作者： Xiang Cheng Zhuo-Ming Xie xue-feng Xie Long-Fei Zeng Rui Liu Jun-feng Yang xue-Bang wu Xian-Ping Wang Chang-Song Liu Qiang-feng Fang Key Laboratory of Materials Physics Institute of Solid State PhysicsHFIPSChinese Academy of SciencesHefei 230031China University of Science and Technology of China Hefei 230026China Faculty of Materials Metallurgy and Chemistry Jiangxi University of Science and TechnologyGanzhou 341000China

Hot-swaging yields a high ultimate tensile strength of 712 MPa but a limited tensile ductility with the total elongation of3.6%at a testing temperature of 200℃in a representative W-0.5wt.%ZrC *** this work,the evolution of Vickers microhardness with annealing temperatures is investigated in detail,which contributes to a rough index chart to guide the search for an optimized post-annealing *** the post-annealing around 1300℃,an outstanding tensile ductility at200℃,including a uniform elongation of 14%and a total elongation of~25%,has been achieved without the sacrifice of its *** evolution of dislocations and grain structures with the annealing temperatures accessed through backscattered scanning electron microscope and transmission electron microscope analysis reveals that the improved low-temperature tensile ductility has resulted from the reduction of residual dislocations and dislocation tanglement via the static recovery,which provides more room to accommodate dislocations,and hence stronger strain hardening ability and tensile ductility.

关键词： Tungsten Low-temperature ductility Annealing Dislocations

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Mechanical property of cylindrical sandwich shell with gradient core of entangled wire mesh

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Defence Technology（防务技术） 2024年第1期31卷 510-522页

作者： Xin xue Chao Zheng Fu-qiang Lai xue-qian wu Institute of Metal-rubber&Vibration Noise School of Mechanical Engineering and AutomationFuzhou UniversityFuzhou350116China Fujian Metallurgical Industry Design Institute Fuzhou350116China

To explore the wide-frequency damping and vibration-attenuation performances in the application of aerospace components,the cylindrical sandwich shell structure with a gradient core of entangled wire mesh was proposed in this ***,the gradient cores of entangled wire mesh in the axial and radial directions were prepared by using an in-house Numerical Control weaving machine,and the metallurgical connection between skin sheets and the gradient core was performed using vacuum ***,to investigate the mechanical properties of cylindrical sandwich shells with axial or radial gradient cores,quasi-static and dynamic mechanical experiments were carried *** primary evaluations of mechanical properties include secant stiffness,natural frequency,Specific Energy Absorption(SEA),vibration acceleration level,and so *** results suggest that the vibration-attenuation performance of the sandwich shell is remarkable when the high-density core layer is at the end of the shell or abuts the inner *** axial gradient material has almost no influence on the vibration frequencies of the shell,whereas the vibration frequencies increase dramatically when the high-density core layer approaches the ***,compared to the conventional sandwich shells,the proposed functional grading cylindrical sandwich shell exhibits more potential in mass reduction,stiffness designing,and energy dissipation.

关键词： Entangled wire mesh Gradient cylindrical sandwich shell Vacuum brazing Secant stiffness Damping

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Some Convergence Properties for Weighted Sums of Martingale Difference Random Vectors

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Acta Mathematica Sinica,English Series 2024年第4期40卷 1127-1142页

作者： Yi wu xue Jun WANG School of Big Data and Artificial Intelligence Chizhou UniversityChizhou 247000P.R.China School of Big Data and Statistics Anhui UniversityHefei 230601P.R.China

Let{X_(ni),F_(ni);1≤i≤n,n≥1}be an array of R^(d)martingale difference random vectors and{A_(ni),1≤i≤n,n≥1}be an array of m×d matrices of real *** this paper,the Marcinkiewicz-Zygmund type weak law of large numb... 详细信息

关键词： Martingale difference random vectors weighted sums Marcinkiewicz–Zygmund type weak law of large numbers complete convergence strong law of large numbers multivariate simple linear regression model

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Early afterglows from radially structured outflows and the application to X-ray shallow decays

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Research in Astronomy and Astrophysics 2009年第8期9卷 911-920页

作者： xue-Wen Liu xue-feng wu Yuan-Chuan Zou Tan Lu Purple Mountain Observatory Chinese Academy of Sciences Nanjing 210008 China Graduate University of Chinese Academy of Sciences Beijing 100049 China Joint Center for Particle Nuclear Physics and Cosmology （J-CPNPC） Nanjing 210093 China Department of Astronomy ＆ Astrophysics Pennsylvania State University University Park PA 16802 USA Department of Physics Huazhong University of Science and Technology Wuhan 430074 China

In the fireball model, it is more physically realistic that ganuna-ray burst （GRB） ejecta have a range of bulk Lorentz factors （assuming M ∝ Г^-8）. The low Lorentz factor part of the ejecta will catch up with the high Lorentz factor part when the latter is decelerated by the surrounding medium to a comparable Lorentz factor. Such a process will develop a long-lasting weak reverse shock until the whole ejecta are shocked. Meanwhile, the forward shocked materials are gradually supplied with energy from the ejecta that are catching-up, and thus the temporal decay of the forward shock emission will be slower than that without an energy supply. However, the reverse shock may be strong. Here, we extend the standard reverse-forward shock model to the case of radially nonuniform ejecta. We show that this process can be classified into two cases： the thick shell case and the thin shell case. In the thin shell case, the reverse shock is weak and the temporal scaling law of the afterglow is the same as that in Sad ＆ Meszaros （2000）. However, in the thick shell case, the reverse shock is strong and thus its emission dominates the afterglow in the high energy band. Our results also show slower decaying behavior of the afterglow due to the energy supply by low Lorentz factor materials, which may help the understanding of the plateau observed in the early optical and X-ray afterglows.

关键词： gamma-rays bursts -- hydrodynamics -- radiation mechanisms nonther- mal -- shock waves

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Polarization of GRB prompt emission and its application to POLAR’s data

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Research in Astronomy and Astrophysics 2021年第3期21卷 43-56页

作者： Mi-Xiang Lan xue-feng wu Zi-Gao Dai Center for Theoretical Physics and College of Physics Jilin UniversityChangchun 130012China Purple Mountain Observatory Chinese Academy of SciencesNanjing 210008China School of Astronomy and Space Science Nanjing UniversityNanjing 210093China Key Laboratory of Modern Astronomy and Astrophysics(Nanjing University) Ministry of EducationNanjing 210093China

Synchrotron emission polarization is very sensitive to the magnetic field ***,polarization of synchrotron emission with a mixed(SM)magnetic field in the gamma-ray burst(GRB)afterglow phase has been ***,we apply these SM models to the GRB prompt phase and compare their polarization properties with that of synchrotron emission in purely ordered(SO)magnetic *** find that the polarization properties in an SM model are very similar to these in a corresponding SO model(e.g.,synchrotron emission in a mixed magnetic field with an aligned ordered part(SMA)and synchrotron emission with a purely ordered aligned magnetic field(SOA)),only with a lower polarization degree(PD).We also discuss the statistical properties of the *** find PDs of the simulated bursts are concentrated around 25%for both SOA and synchrotron emission in a purely ordered toroidal magnetic field(SOT),while they can range from 0%to 25%for SMA and synchrotron emission in a mixed magnetic field with a toroidal ordered part(SMT),depending onξ_B value,i.e.,the ratio of magnetic reduction of the ordered magnetic field over that of random magnetic *** statistics,if PDs of majority GRBs are non-zero,then it favors SO and SM ***,if there are some bright GRBs with prominently lower PDs than that of the majority GRBs,it favors SOT(SMT)models;if all the bright GRBs have comparable PDs with the majority ones,it favors SOA(SMA)***,we apply our results to POLAR’s data and find that~10%time-integrated PDs of the observed bursts favor SMA and SMT models,and theξ_B parameter of these bursts is constrained to be around 1.135.

关键词： gamma-ray burst:general magnetic fields polarization radiation mechanisms:nonthermal

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A Hf-doped dual-phase high-entropy alloy: phase evolution and wear features

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Rare Metals 2024年第1期43卷 324-333页

作者： Hao Ren Rui-Run Chen xue-feng Gao Tong Liu Gang Qin Yu-Lung Chiu Shi-Ping wu Jing-Jie Guo National Key Laboratory for Precision Hot Processing of Metals School of Materials Science and EngineeringHarbin Institute of TechnologyHarbin 150001China School of Metallurgy and Materials University of BirminghamEdgbastonBirmingham B152TTUK

Initially defined high entropy alloys(HEAs)usually exhibit a single-phase solid-solution ***,two and/or more types of phases in HE As possibly induce the desired microstructure features,which contribute to improving the wear properties of HE ***,we prepare a series of(AlCoCrFeNi)_(100-x)Hf_(x)(x=0,2,4and 6;at%) HEAs and concern their phase compositions,micro structures and wear *** leads to the formation of(Ni,Co)_(2)Hf-type Laves phase and tailors the microstructure from a body-centered cubic(BCC) singlephase structure to a hypoeutectic *** increased hardness from~HV 512.3 to~HV 734.1 is due to solid-solution strengthening,grain refinement strengthening and precipitated phase *** a few oxides(Al_(2)O_(3)+Cr_(2)O_(3)) caused by the wear heating contribute to an 85.5% decrease in wear rate of the HEA system from6.71×10^(-5) to 0.97×10^(-5) m^(3)·N^(-1)·m^(-1).In addition,Hf addition changes the wear mechanism from abrasive wear,mild oxidative wear and adhesive wear to oxidative wear and adhesive wear.

关键词： High entropy alloy Laves phase Hardness Wear mechanism

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