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Gravitational waves and primordial black hole productions from gluodynamics by holography

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science China(Physics,Mechanics & Astronomy) 2024年第4期67卷 31-42页

作者： song He li li Zhibin li shao-Jiang wang Center for Theoretical Physics and College of Physics Jilin UniversityChangchun 130012China Max Planck Institute for Gravitational Physics(Albert Einstein Institute) Golm 14476Germany CAs Key laboratory of Theoretical Physics Institute of Theoretical PhysicsChinese Academy of SciencesBeijing 100190China school of Fundamental Physics and Mathematical sciences Hangzhou Institute for Advanced StudyUniversity of Chinese Academy of SciencesHangzhou 310024China Peng Huanwu Collaborative Center for Research and Education Beihang UniversityBeijing 100191China school of Physics and Microelectronics Zhengzhou UniversityZhengzhou 450001China

Understanding the nature of quantum chromodynamics(QCD)matter is important but challenging due to the presence of nonperturbative dynamics under extreme *** construct a holographic model describing the gluon sector of QCD at finite temperatures in the non-perturbative *** equation of state as a function of temperature is in good accordance with the lattice QCD ***,the Polyakov loop and the gluon condensation,which are proper order parameters to capture the deconfinement phase transition,also agree quantitatively well with the lattice QCD *** obtain a strong first-order confinement/deconfinement phase transition at Tc=276.5 Me v that is consistent with the lattice QCD *** on our model for a pure gluon hidden sector,we compute the stochastic gravitational waves and primordial black hole(PBH)productions from this confinement/deconfinement phase transition in the early *** resulting stochastic gravitational-wave backgrounds are found to be within detectability in the International Pulsar Timing Array and square Kilometre Array in the near future when the associated productions of PBHs saturate the current observational bounds on the PBH abundances from the lIGO-virgo-Collaboration O3 data.

关键词： Ads/QCD confinement/deconfinement phase transition gravitational wave primordial black hole

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Contrasts of bimodal tropical instability waves(TIWs)-induced wind stress perturbations in the Pacific Ocean among observations,ocean models,and coupled climate models

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Journal of Oceanology and limnology 2024年第1期42卷 1-23页

作者： Kai MA Chuanyu lIU Junli XU Fan wang school of Mathematics and Physics Research Institute for Mathematics and Interdisciplinary SciencesQingdao University of Science and TechnologyQingdao 266100China Key laboratory of Ocean Circulation and Waves Institute of OceanologyChinese Academy of SciencesQingdao 266071China Pilot national laboratory for Marine science and Technology(Qingdao) Qingdao 266237China

The coupling between wind stress perturbations and sea surface temperature(ssT)perturbations induced by tropical instability waves(TIWs)in the Pacific Ocean has been revealed previously and proven crucial to both the atmosphere and ***,an overlooked fact by previous studies is that the loosely defined“TIWs”actually consist of two modes,including the Yanai wave-based TIW on the equator(hereafter eTIW)and the Rossby wave-based TIW off the equator(hereafter vTIW).Hence,the individual feedbacks of the wind stress to the bimodal TIWs remain *** this study,individual coupling relationships are established for both eTIW and v TIW,including the relationship between the TIW-induced ssT perturbations and two components of wind stress perturbations,and the relationship between the TIW-induced wind stress perturbation divergence(curl)and the downwind(crosswind)TIW-induced ssT *** show that,due to different distributions of eTIW and vTIW,the coupling strength induced by the eTIW is stronger on the equator,and that by the vTIW is stronger off the *** results of any of eTIW and vTIW are higher than those of the loosely defined *** further investigated how well the coupling relationships remained in several widely recognized oceanic general circulation models and fully coupled climate ***,the coupling relationships cannot be well represented in most numerical ***,we confirmed that higher resolution usually corresponds to more accurate ***,the coupling models established in this study are complementary to previous research and can be used to refine the oceanic and coupled climate models.

关键词： bimodal tropical instability waves mesoscale air-sea interaction coupled models Yanai wave

A stable implicit nodal integration-based particle finite element method(n-PFEM)for modelling saturated soil dynamics

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第6期16卷 2172-2183页

作者： liang wang Xue Zhang Jingjing Meng Qinghua lei Department of Earth sciences ETH ZürichZürich8092Switzerland Department of Civil Engineering and Industrial Design University of LiverpoolLiverpoolL693BXUK Department of Civil Environmental and Natural Resources EngineeringLuleåUniversity of TechnologyLuleå97187Sweden Department of Earth sciences Uppsala UniversityUppsala75105Sweden

In this study,we present a novel nodal integration-based particle finite element method(n-PFEM)designed for the dynamic analysis of saturated *** approach incorporates the nodal integration technique into a generalised Hellinger-Reissner(HR)variational principle,creating an implicit PFEM *** mitigate the volumetric locking issue in low-order elements,we employ a node-based strain smoothing *** discretising field variables at the centre of smoothing cells,we achieve nodal integration over cells,eliminating the need for sophisticated mapping operations after re-meshing in the *** express the discretised governing equations as a min-max optimisation problem,which is further reformulated as a standard second-order cone programming(sOCP)***,pore water pressure,and displacements are simultaneously determined using the advanced primal-dual interior point ***,our numerical model offers improved accuracy for stresses and pore water pressure compared to the displacement-based PFEM *** experiments demonstrate that the n-PFEM efficiently captures both transient and long-term hydro-mechanical behaviour of saturated soils with high accuracy,obviating the need for stabilisation or regularisation techniques commonly employed in other nodal integration-based PFEM *** work holds significant implications for the development of robust and accurate numerical tools for studying saturated soil dynamics.

关键词： Particle finite element method nodal integration Dynamic saturated media second-order cone programming(sOCP)

nitric oxide assists nitrogen reduction reaction on 2D MBene: A theoretical study

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Chinese Chemical letters 2024年第5期35卷 428-433页

作者： Chaozheng He Jia wang ling Fu Wei Wei Henan Engineering Center of new Energy Battery Materials College of Chemistry and Chemical EngineeringShangqiu Normal UniversityShangqiu 476000China school of Chemistry and Chemical Engineering Shandong Provincial Key Laboratory/Collaborative Innovation Center of Chemical Energy Storage&Novel Cell TechnologyLiaocheng UniversityLiaocheng 252059China Institute of Environment and Energy Catalysis Shaanxi Key Laboratory of Optoelectronic Functional Materials and DevicesSchool of Materials Science and Chemical EngineeringXi’an Technological UniversityXi’an 710021China College of Resources and Environmental Engineering Tianshui Normal UniversityTianshui 741001China

Electrocatalytic synthesis of ammonia as an environment-friendly and sustainable development method has received widespread attention in recent ***-dimensional(2D)materials are a promising catalyst for ammonia synthesis due to their large surface *** this work,we have constructed a series of 2D metal borides(MBenes)with transition metal(TM)defects(TMd-MBenes)and comprehensively calculated the reactivity of electrocatalytic synthesis of ammonia-based on density functional *** results have demonstrated that the TMd-MBenes can effectively activate nitrogen oxide(nO)and nitrogen(n2)molecules *** interesting,the co-chemisorption of O atoms,dissociated from nO,can facilitate the spilled of the inert n2 molecules into single n atoms,which can further hydrogenate into ammonia easily with an ultralow limiting potential of 0.59 v on *** research has not only provided clues for catalyst design for experimental study but also paved the way for the industrial application of electrocatalytic ammonia synthesis.

关键词： 2D mbenes nitrogen electro-reduction DFT n_(2)activation Ammonia synthesis

Observation of high ionic conductivity of polyelectrolyte microgels in salt-free solutions

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Chinese Chemical letters 2024年第4期35卷 255-259页

作者： Qiangwei wang Huijiao liu Mengjie wang Haojie Zhang Jianda Xie Xuanwei Hu shiming Zhou Weitai Wu state Key laboratory for Physical Chemistry of solid surfaces Collaborative Innovation Center of Chemistry for Energy MaterialsThe Key Laboratory for Chemical Biology of Fujian Provinceand Department of ChemistryCollege of Chemistry and Chemical EngineeringXiamen UniversityXiamen 361005China school of Materials science and Engineering Xiamen University of TechnologyXiamen 361024China Hefei national laboratory for Physical sciences at the Microscale University of Science and Technology of ChinaHefei 230026China school of Chemistry and Chemical Engineering Ningxia UniversityYinchuan 750021China

Here, we report an observation that illustrate the potential of polyelectrolyte microgels in salt-free solutions to display a high ionic conductivity. laser light scattering and ionic conductivity tests on very dilute aqueous dispersions of the microgels indicate that both small size and swollen state of gel particles play vital roles, which should favor the counterions to freely penetrate and leave gel particles, and thus can contribute to the ion-conducting property. Upon discovering this on microgels that are composed of imidazolium-based poly(ionic liquid), we also illustrate the generality of the finding to single lithium-ion polyelectrolyte microgels that are of more technically relevant features for applications, for instance, as injectable liquid “microgel-in-solution” electrolytes of high conductivity(ca. 8.2 × 10^(-2)s/m at 25.0 ℃ for1.0 × 10^(-2)g/m l of microgels in a linO_(3)-free 1:1 v/v mixture of 1,2-dioxolane and dimethoxymethane) and high lithium-ion transference number(0.87) for use in the rechargeable lithium-sulfur battery.

关键词： Polyelectrolhyte stimuli-responsive single-ion conducting liquid electrolyte lithium metal battery

MOF-derived porous graphitic carbon with optimized plateau capacity and rate capability for high performance lithium-ion capacitors

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International Journal of Minerals,Metallurgy and Materials 2024年第2期31卷 395-404页

作者： Ge Chu Chaohui wang Zhewei Yang lin Qin Xin Fan College of Materials science&Engineering Guilin University of TechnologyGuilin 541004China Institute of Energy Innovation College of Materials Science and EngineeringTaiyuan University of TechnologyTaiyuan 030024China

The development of anode materials with high rate capability and long charge-discharge plateau is the key to improve per-formance of lithium-ion capacitors(lICs).Herein,the porous graphitic carbon(PGC-1300)derived from a new triply interpenetrated co-balt metal-organic framework(Co-MOF)was prepared through the facile and robust carbonization at 1300°C and washing by HCl *** as-prepared PGC-1300 featured an optimized graphitization degree and porous framework,which not only contributes to high plateau capacity(105.0 mAh·g^(−1)below 0.2 v at 0.05 A·g^(−1)),but also supplies more convenient pathways for ions and increases the rate capability(128.5 mAh·g^(−1)at 3.2 A·g^(−1)).According to the kinetics analyses,it can be found that diffusion regulated surface induced capa-citive process and li-ions intercalation process are coexisted for lithium-ion ***,lIC PGC-1300//AC constructed with pre-lithiated PGC-1300 anode and activated carbon(AC)cathode exhibited an increased energy density of 102.8 Wh·kg^(−1),a power dens-ity of 6017.1 W·kg^(−1),together with the excellent cyclic stability(91.6%retention after 10000 cycles at 1.0 A·g^(−1)).

关键词： metal-organic framework porous graphitic carbon optimized plateau capacity kinetic analysis lithium-ion capacitor

High Power Density Ev Integrated Fast Battery Chargers Based on the General Torque Cancelation law for Three-Phase Motors

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CsEE Journal of Power and Energy systems 2024年第2期10卷 756-766页

作者： Yanxiong lei Guiping Du Tuhuan li Wenjie Ma Xueyi wang school of Electric Power South China University of TechnologyGuangzhou 510641China

Integrated battery chargers are highly effective for saving costs and improving the power density of on-board chargers in electric vehicles (Evs), However, achieving torque elimination of the commonly used three-phase (3p) motors during the fast-charging process is challenging. In this paper, the general torque cancelation law applied in 3p permanent magnet synchronous motors (PMsMs) and induction motors (IMs) is derived to design high power density integrated fast battery chargers. Two novel integrated systems with fast-charging and vehicle-to-grid (v2G) capabilities are proposed based on this law. The main advantages of the proposed systems are: (1) Two filter inductors are constituted by the stator windings while charging, and only one external inductor and several contactors are supplemented to the motor-drive circuit. Therefore, the proposed integrated systems possess high power density;(2) The 3p open-winding (OW) motor is employed, with no need to modify the propulsion system or redesign the interior structure of the motor;(3) Employing an individual controller for each phase of the inner current loop control, the proposed systems realize unity power factors and low current harmonics in the fast-charging and v2G mode. simulation and experimental results verify the feasibility of the proposed topologies and control strategies.

关键词： Electric vehicles(Evs) fast charging integrated battery charger 3p PMsM/IM torque cancelation

Melt flow,heat transfer and solidification in a flexible thin slab continuous casting mold with vertical-combined electromagnetic braking

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Journal of Iron and steel Research(International) 2024年第2期31卷 401-415页

作者： lin Xu Ze-feng Han Christian Karcher En-gang wang Key laboratory of Electromagnetic Processing of Materials(Ministry of Education) Northeastern UniversityShenyang110819LiaoningChina Key laboratory of liaoning Province for Clean Combustion Power Generation and Heating Technology Shenyang Institute of EngineeringShenyang110136LiaoningChina Institute of Thermodynamics and Fluid Mechanics Technische Universität IlmenauIlmenau98684Germany

During continuous casting of steel slabs,the application of electromagnetic braking technology(EMBr)provides an effective tool to influence solidification by controlling the pattern of melt flow in the ***,the quality of the final product can be improved considerably.A new electromagnetic braking(EMBr)method,named vertical-combined electromagnetic braking(vC-EMBr),is proposed to be applied to a flexible thin slab casting(FTsC)*** evaluate the beneficial effects of the vC-EMBr,the melt flow,heat transfer,and solidification processes in the FTsC mold are studied by means of numerical *** detail,a Reynolds-averaged navier–stokes turbulence model together with an enthalpy-porosity approach was *** numerical findings are compared with respective simulations using the traditional *** results demonstrate that the application of the vC-EMBr contributes significantly to preventing relative slab *** contrast to the Ruler-EMBr,the additional vertical magnetic poles of the vC-EMBr preferentially suppress the direct impact of jet flow on the narrow face of FsTC mold and considerably diminish the level fluctuation near the meniscus *** instance,by applying a magnetic flux density of 0.3 T,the maximum amplitude of meniscus deflection reduces by about 80%.Moreover,the braking effect of the vC-EMBr effectively improves the homogeneity of temperature distribution in the upper recirculation region and increases the solidified shell thickness along the casting *** this basis,the newly proposed vC-EMBr shows a beneficial effect in preventing relative slab defects for FTsC thin slab continuous casting.

关键词： Electromagnetic braking Mold Melt flow Heat transfer solidification

numerical Investigation on Heat Transfer Characteristics of Microencapsulated Phase Change Material slurry in a Rectangular Minichannel

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Journal of Thermal science 2024年第2期33卷 564-577页

作者： wang Zhibin lI Zilong JIA lisi DInG Bin CHEn Ying school of Materials and Energy Guangdong University of TechnologyGuangzhou510006China Guangdong Provincial Key laboratory of Functional soft Condensed Matter Guangzhou510006China College of new Energy China University of Petroleum(East China)Qingdao266580China

Microencapsulation phase change material slurry(MEPCMs) becomes a potential working fluid for cooling high energy density miniaturized components,thanks to the latent heat absorption of particles in the heat transfer *** this work,the Discrete Phase Model(DPM) based on the Euler-lagrangian method is used to numerically investigate the convective heat transfer characteristics of MEPCMs flowing through a rectangular minichannel with constant heat *** results show that particles of MEPCMs are mainly subjected to drag force during the *** so,they can migrate from the high-temperature region to the low-temperature region driven by the thermophoretic force,affecting the particle distribution and phase change ***,the nux of the MEPCMs fluctuates due to particle phase change with varying specific heat ***,the value increases first,then decreases,and eventually increases again until it approaches the fully developed value of the pure base fluid as the particles gradually ***,the heat transfer performance of the MEPCMs is influenced by the combination of fluid inlet temperature fluid inlet velocity(v),and mass concentration(c_(m)) of MEPCM *** result shows that the maximum reduction of the maximum bottom wall temperature difference(ΔT_(w)) is 23.98% at T_(in)=293.15 K,v=0.15 m·s^(-1),c_(m)=10%.

关键词： Microencapsulated Phase Change Material slurry(MPCMs) Discrete Phase Model(DPM) particle-fluid interaction force minichannel heat sink thermophoresis