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Self-separation ionic liquid catalyst for the highly effective conversion of H2S by α,β-unsaturated carboxylate esters under mild conditions

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Green Energy & Environment 2024年第9期9卷 1440-1448页

作者： Wenjie Xiong Xiaomin Zhang Xingbang Hu Youting Wu Key Laboratory of Mesoscopic Chemistry of MOE School of Chemistry and Chemical Engineering Nanjing University The Institute of Green Chemistry and Engineering School of Chemistry and Chemical Engineering Nanjing University

The deep-processing utility of pure hydrogen sulfide （H2S） is a significant direction in natural gas chemical ***,a brand-new strategy of H2S conversion by a,β-unsaturated carboxylate esters into thiols or thioethers using task-specific carboxylate ionic liquids （ILs） as catalyst has been developed,firstly accomplishing the phase separation of product and catalyst without introducing the third *** can be considered as a cascade reaction in which the product selectivity can be controlled by adjusting the molar ratio of H2S to a,β-unsaturated carboxylate ***,the effects of ILs with different anions and cations,intermittent feeding operations,as well as pressure-time kinetic behaviors on cascade reaction were ***,the proposed interaction mechanism of H2S conversion using butyl acrylate catalyzed by[Emim][Ac]was revealed by DFT-based theoretical *** approach enables the self-phase separation promotion of catalyst and product and achieves 99%quantitative conversion under mild conditions in the absence of solvent,making the entire process ecologically ***-efficiency reaction activity can still be maintained after ten cycles of the ***,the good results,combined with its simplicity of operation and the high recyclability of the catalyst,make this green method environmentally friendly and *** is anticipated that this self-separation method mediated by task-specific ILs will provide a feasible strategy for H2S utilization,which will guide its application on an industrial scale.

关键词： Ionic liquid Cascade reaction Self-separation H 2 S conversion Catalysis

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Role of alloying and heat treatment on microstructure and mechanical properties of cast Al-Li alloys:A review

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china Foundry 2024年第5期21卷 445-460页

作者： Guo-hua Wu You-jie Guo Fang-zhou Qi Shen Zhang Yi-xiao Wang Xin Tong Liang Zhang School of Materials science and Engineering Shanghai Jiao Tong UniversityShanghai 200240China

Due to the prominent advantages of low density,high elastic modulus,high specific strength and specific stiffness,cast Al-Li alloys are suitable metallic materials for manufacturing complex large-sized components and are ideal structural materials for aerospace,defense and military *** the basis of the microstructural characteristics of cast Al-Li alloys,exploring the role of alloying and micro-alloying can stabilize their dominant position and further expand their application *** this review,the development progress of cast Al-Li alloys was summarized *** to the latest research highlights,the influence of alloying and heat treatment on the microstructure and mechanical properties was systematically *** potential methods to improve the alloy performance were *** response to the practical engineering requirements of cast Al-Li alloys,the scientific challenges and future research directions were discussed and prospected.

关键词： cast Al-Li alloy alloying microstructure mechanical properties heat treatment

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Creep damage evolution process of asphalt binder based on viscoelastic characteristics

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Journal of Traffic and Transportation Engineering(English Edition) 2024年第3期11卷 497-506页

作者： Xiaofei Qi Shuang Tian Liyan Shan Shuang Liu Yajie Wang School of Transportation science and Engineering Harbin Institute of TechnologyHarbin 150090China College of Water Conservancy&Architectural Engineering Shihezi UniversityShihezi 832003China

The creep damage evolution of asphalt binder plays a significant role in investigating the formation mechanism of *** rutting is the common distress at high temperatures for asphalt ***,the reliability of existing creep damage parameters is under questioned,and these parameters cannot accurately illustrate the change of intrinsic microstructure for asphalt *** this paper,a new test protocol was given access to study the evolution of viscoelastic parameters during creep *** was completed by inserting the frequency sweep during creep *** frequency sweep curve clusters were fitted by the generalized Kelvin-Voigt model for obtaining the change law of model *** on the change law and sensitivity analysis of model parameters,(E_(2)+E_(3))/2 was proposed as the creep damage *** to the curve of(E_(2)+E_(3))/2 versus loading time,two stages during the creep test could be identified:an approximate constant value in phase I and a linear decrease in phase *** differences about creep property of binders could be determined by this new proposed *** results not only ensure better understanding of the creep damage mechanism of binders,but also lay the theoretical foundation on predicting the anti-rutting performance of binders.

关键词： Asphalt binder Multi-stage creep test Damage variable Evolution law

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Gelatin-Based Metamaterial Hydrogel Films with High Conformality for Ultra-Soft Tissue Monitoring

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Nano-Micro Letters 2024年第2期16卷 347-364页

作者： Yuewei Chen Yanyan Zhou Zihe Hu Weiying Lu Zhuang Li Ning Gao Nian Liu Yuanrong Li Jing He Qing Gao Zhijian Xie Jiachun Li Yong He State Key Laboratory of Fluid Power and Mechatronic Systems School of Mechanical EngineeringZhejiang UniversityHangzhou 310027People’s Republic of China School of Mechanical Engineering Guizhou UniversityGuiyang 550025People’s Republic of China Stomatology Hospital School of StomatologyZhejiang University School of MedicineClinical Research Center for Oral Diseases of Zhejiang ProvinceKey Laboratory of Oral Biomedical Research of Zhejiang ProvinceCancer Center of Zhejiang UniversityHangzhou 310006People’s Republic of China

Implantable hydrogel-based bioelectronics(IHB)can precisely monitor human health and diagnose ***,achieving biodegradability,biocompatibility,and high conformality with soft tissues poses significant challenges for *** is the most suitable candidate for IHB since it is a collagen hydrolysate and a substantial part of the extracellular matrix found naturally in most *** study used 3D printing ultrafine fiber networks with metamaterial design to embed into ultra-low elastic modulus hydrogel to create a novel gelatin-based conductive film(GCF)with mechanical *** regulation of GCF nearly covers soft tissue mechanics,an elastic modulus from 20 to 420 kPa,and a Poisson’s ratio from-0.25 to *** negative Poisson’s ratio promotes conformality with soft tissues to improve the efficiency of biological *** GCF can monitor heartbeat signals and respiratory rate by determining cardiac deformation due to its high ***,the gelatin characteristics of the biodegradable GCF enable the sensor to monitor and support tissue *** GCF metamaterial design offers a unique idea for bioelectronics to develop implantable sensors that integrate monitoring and tissue repair and a customized method for endowing implanted sensors to be highly conformal with soft tissues.

关键词： Implantable hydrogel-based bioelectronics Conformality 3D printing Metamaterial design

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Ren-integrable and ren-symmetric integrable systems

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Communications in Theoretical Physics 2024年第3期76卷 62-69页

作者： S Y Lou School of Physical science and Technology Ningbo UniversityNingbo315211China

A new type of symmetry,ren-symmetry,describing anyon physics and corresponding topological physics,is ***-symmetry is a generalization of super-symmetry which is widely applied in super-symmetric physics such as super-symmetric quantum mechanics,super-symmetric gravity,super-symmetric string theory,super-symmetric integrable systems and so *** and Grassmann numbers are,in some sense,dual conceptions,and it turns out that these conceptions coincide for the ren situation,that is,a similar conception of ren-number(R-number)is devised for *** particular,some basic results of the R-number and ren-symmetry are exposed which allow one to derive,in principle,some new types of integrable systems including ren-integrable models and ren-symmetric integrable *** examples of ren-integrable KdV-type systems and ren-symmetric KdV equations are explicitly given.

关键词： symmetries integrable systems anyon physics extended supersymmetry ren-symmetry

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Near-Field Heat Transfer Enhancement of SiC-hBN-InSb Thermophotovoltaic System by Graphene Strong Coupling Effects

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Journal of Thermal science 2024年第4期33卷 1409-1420页

作者： XU Zhiguo HU Zhifang School of Mechanical Engineering Shanghai Jiao Tong UniversityShanghai200240China

Near-field thermophotovoltaic(NTPV)devices comprising a SiC-hBN-graphene emitter and a graphene-InSb cell with gratings are designed to enhance the performance of the NTPV *** electrodynamics and rigorous coupled-wave analysis are employed to calculate radiative heat transfer *** is found that the NTPV systems with two graphene ribbons perform better due to the graphene strong coupling *** effects of graphene chemical potential are *** is demonstrated that near-field radiative heat transfer of thermophotovoltaic devices is enhanced by the coupling of surface plasmon polaritons,surface phonon polaritons,hyperbolic phonon polaritons,and magnetic polaritons caused by the graphene strong coupling *** splitting frequency of different polaritons is calculated to quantify the mutual interaction of graphene strong coupling ***,the effects of cell grating filling ratio are *** excitation of magnetic polaritons is affected by the graphene ribbon and the cell filling *** investigation provides a new explanation of the enhancement mechanism of graphene-assisted thermophotovoltaic systems and a novel approach for improving the output power of the near-field thermophotovoltaic system.

关键词： near-field radiative heat transfer thermophotovoltaics strong coupling effect multiple magnetic polaritons graphene-hbn heterostructures

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Turbulence Statistics of Thermo-Buoyancy Supercritical Fuel Flow in a Regenerative Cooling Channel

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Journal of Thermal science 2024年第1期33卷 126-137页

作者： SUN Feng XIE Gongnan School of Marine science and Technology Northwestern Polytechnical UniversityXi'an 710072China Department of Thermal Engineering Tsinghua UniversityBeijing 100084China

Active regenerative cooling with supercritical hydrocarbon fuel is considered as the most promising thermal protection *** existence of buoyancy force would lead to strongly anisotropic flow and thermal transport *** is closely related to the cooling performance of the *** elucidate the mechanisms of turbulent transport,the large eddy simulation(LES) was performed to assess turbulence statistics within different turbulence *** results indicated that the buoyancy and inertial force together dominated the change of turbulent ***,the spatial thermal buoyancy effect significantly suppressed the vertical velocity *** is due to the laminar motion caused by the buoyancy force,thereby weakening the thermal *** the statistics of velocity fluctuation,it was found that the buoyancy force and inertial force greatly weaken the vertical and streamwise velocity fluctuation,*** the statistics of thermal transport,the results pointed out that the near-wall heat transport characteristics need to be paid more *** thickness of the temperature mixing boundary layer led to the attenuation of vertical heat flux,which inhibited vertical temperature diffusion and predisposed to extreme conditions of heat transfer *** results can enhance the academic understanding of the heat transfer mechanism of supercritical fluids,and give guidance for further applications of thermal protection.

关键词： active regenerative cooling large eddy simulation(LES) buoyancy force turbulence statistics

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SHA: QoS-Aware Software and Hardware Auto-Tuning for Database Systems

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Journal of Computer science & Technology 2024年第2期39卷 369-383页

作者：李进陈全唐晓新过敏意 Department of Computer science Shanghai Jiao Tong UniversityShanghai 200240China Department of Computer science and Technology Shanghai University of Finance and EconomicsShanghai 200433China

While databases are widely-used in commercial user-facing services that have stringent quality-of-service(QoS)requirement,it is crucial to ensure their good performance and minimize the hardware usage at the same *** investigation shows that the optimal DBMS(database management system)software configuration varies for different user request patterns(i.e.,workloads)and hardware *** is challenging to identify the optimal software and hardware configurations for a database workload,because DBMSs have hundreds of tunable knobs,the effect of tuning a knob depends on other knobs,and the dependency relationship changes under different hardware *** this paper,we propose SHA,a software and hardware auto-tuning system for *** is comprised of a scaling-based performance predictor,a reinforcement learning(RL)based software tuner,and a QoS-aware resource *** performance predictor predicts its optimal performance with different hardware configurations and identifies the minimum amount of resources for satisfying its performance *** software tuner fine-tunes the DBMS software knobs to optimize the performance of the *** resource reallocator assigns the saved resources to other applications to improve resource utilization without incurring QoS violation of the database *** results show that SHA improves the performance of database workloads by 9.9%on average compared with a state-of-the-art solution when the hardware configuration is fixed,and improves 43.2%of resource utilization while ensuring the QoS.

关键词： auto-tuning database configuration joint tuning utilization quality-of-service(QoS)

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Quasi-two-dimensional strong liquid-like dynamics of surface atoms in metallic glasses

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science china(Physics,Mechanics & Astronomy) 2024年第3期67卷 102-109页

作者： Bing Wang Xuanqiao Gao Rui Su Pengfei Guan School of Physical science and Technology Northwestern Polytechnical UniversityXi'an 710072China Innovation Center NPU Chongqing Northwestern Polytechnical UniversityChongqing 401135China School of Mechanics Civil Engineering and ArchitectureNorthwestern Polytechnical UniversityXi'an 710072China Northwest Institute for Nonferrous Metal Research Xi'an 710016China Institute of Advanced Magnetic Materials College of Materials and Environmental EngineeringHangzhou Dianzi University Hangzhou 310018China Beijing Computational science Research Center Beijing 100093China

The fast dynamic properties of the surface of metallic glasses(MGs) play a critical role in determining their potential applications. However, due to the significant difference in thermal history between atomic simulation models and laboratory-made samples, the atomic-scale behaviors of the fast surface dynamics of MGs in experiments remain uncertain. Herein, we prepared model MG films with notable variations in thermal stability using a recently developed efficient annealing protocol, and investigated their atomic-scale dynamics systematically. We found that the dynamics of surface atoms remain invariant, whereas the difference in dynamical heterogeneity between surface and interior regions increases with the improvement of thermal stability. This can be associated with the more pronounced correlation between atomic activation energy spectra and depth from the surface in samples with higher thermal stability. In addition, dynamic anisotropy appears for surface atoms, and their transverse dynamics are faster than normal components, which can also be interpreted by activation energy spectra. Our results reveal the presence of strong liquid-like atomic dynamics confined to the surface of laboratory-made MGs, illuminating the underlying mechanisms for surface engineering design, such as cold joining by ultrasonic vibrations and superlattice growth.

关键词： metallic glasses thermal stability invariant surface dynamics potential energy landscape dynamic anisotropy and heterogeneity

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Visualization and characterization of experimental hydraulic fractures interacting with karst fracture-cavity distributions

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第5期16卷 1667-1683页

作者： Hanzhi Yang Xin Chang Chunhe Yang Wuhao Guo Lei Wang Guokai Zhao Yintong Guo State Key Laboratory of Coal Mine Disaster Dynamics and Control Chongqing UniversityChongqing400044China State Key Laboratory of Geomechanics and Geotechnical Engineering Institute of Rock and Soil MechanicsChinese Academy of SciencesWuhan430071China

Karst fracture-cavity carbonate reservoirs,in which natural cavities are connected by natural fractures to form cavity clusters in many circumstances,have become significant fields of oil and gas exploration and *** fracturing is considered as the best method for exploiting carbonate reservoirs;however,previous studies primarily focused on the effects of individual types of geological formations,such as natural fractures or cavities,on fracture *** this study,true-triaxial physical simulation experiments were systematically performed under four types of stress difference conditions after the accurate prefabrication of four types of different fracture-cavity distributions in artificial ***,the interaction mechanism between the hydraulic fractures and fracture-cavity structures was systematically analyzed in combination with the stress distribution,cross-sectional morphology of the main propagation path,and three-dimensional visualization of the overall fracture *** was found that the propagation of hydraulic fractures near the cavity was inhibited by the stress concentration surrounding the *** contrast,a natural fracture with a smaller approach angle(0°and 30°)around the cavity can alleviate the stress concentration and significantly facilitate the connection with the *** addition,the hydraulic fracture crossed the natural fracture at the 45°approach angle and bypassed the cavity under higher stress difference conditions.A new stimulation effectiveness evaluation index was established based on the stimulated reservoir area(SRA),tortuosity of the hydraulic fractures(T),and connectivity index(CI)of the *** findings provide new insights into the fracturing design of carbonate reservoirs.

关键词： Karst fracture-cavity reservoir Fracturing experiment Fracture propagation Cross-sectional morphology Stimulation effectiveness

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