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Process reconfiguration and intensification:An emerging opportunity enabling efficient carbon capture and low-cost blue hydrogen production

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Green Energy & Environment 2023年第4期8卷 945-947页

作者： Dongke zhang Centre for Energy(M473) The University of Western Australia35 Stirling HighwayCrawleyWA 6009Australia

Low-carbon hydrogen can play a significant role in decarbonizing the world. Hydrogen is currently mainly produced from fossil sources,requiring additional CO_(2)capture to decarbonize, which energy intense and costly. In a recent Green Energy & Environment paper, Cheng and Di et al. proposed a novel integration process referred to as SECLR_(HC) to generate high-purity H_(2) by in-situ separation of H_(2)and CO without using any additional separation unit. Theoretically, the proposed process can essentially achieve the separation of C and H in gaseous fuel via a reconfigured reaction process, and thus attaining high-purity hydrogen of ~99%, as well as good carbon and hydrogen utilization rates and economic feasibility. It displays an optimistic prospect that industrial decarbonization is not necessarily expensive, as long as a suitable CCS measure can be integrated into the industrial manufacturing process.

关键词： Chemical looping Hydrogen Low energy cost Reconfigured reaction Industrial decarbonization

Finite p-Groups all of Whose Maximal Subgroups Either are Metacyclic or Have a Derived Subgroup of Order ≤ p

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Chinese Annals of Mathematics,Series B 2015年第1期36卷 11-30页

作者： Lihua zhang Yanming XIA Qinhai zhang Department of Mathematics Beijing University of Posts and Telecommunications Department of Mathematics Shanxi Normal University

The groups as mentioned in the title are classified up to isomorphism. This is an answer to a question proposed by Berkovich and Janko.

关键词： Finite p-groups Nonmetacyclic p-groups Minimal nonabelian p-groups Maximal subgroups

Applications of sediment sudden deposition model based on the third-generation numerical model for shallow water wave

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Acta Oceanologica Sinica 2007年第3期26卷 142-149页

作者： BAI Yuchuan zhang Yinqi zhang Bin Institute of Sediment on River and Coast Engineering Tianjin University Tianjin 300072 China China Communication Construction Corporation First Harbor Consultants Co. Ltd Tianjin 300222 China

The existing numerical models for nearshore waves are briefly introduced, and the third-generation numerical model for shallow water wave, which makes use of the most advanced productions of wave research and has been adapted well to be used in the environment of seacoast, lake and estuary area, is particularly discussed. The applied model realizes the significant wave height distribution at different wind directions. To integrate the model into the coastal area sediment, sudden deposition mechanism, the distribution of average silt content and the change of sediment sudden deposition thickness over time in the nearshore area are simulated. The academic productions can give some theoretical guidance to the applications of sediment sudden deposition mechanism for stormy waves in the coastal area. And the advancing directions of sediment sudden deposition model are prospected.

关键词： Boussinesq equation mild-slope equation third-generation numerical model for shallow water wave sedimentsudden deposition

Thermoelastic Damping of Functionally Graded Material Micro-Beam Resonators Based on the Modified Couple Stress Theory

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Acta Mechanica Solida Sinica 2020年第4期33卷 496-507页

作者： Zhichao zhang Shirong Liu School of Civil Engineering and Science Yangzhou UniversityYangzhou 225127China

Thermoelastic damping(TED)is one of the main internal energy dissipation mechanisms in micro/*** evaluation of TED is important in the design of micro-electromechanical systems and nano-electromechanical *** this paper,a theoretical analysis on the TED in functionally graded material(FGM)micro-beam resonators is *** of motion and the heat conduction equation governing the thermodynamic coupling free vibration of non-homogenous micro-beams are established based on the Euler Bernoulli beam theory associated with the modified couple stress *** properties of the FGM micro-beam are assumed to change in the depth direction as power-law *** layer-wise homogenization method is used for solving the heat conduction *** using the mathematical similarity of eigenvalue problem between the FGM beam and the reference homogeneous one,the complex natural frequency including TED is expressed in terms of the natural frequency of the isothermal homogenous *** the presented numerical results,influences of various characteristic parameters,such as beam thickness,material gradient index,structure size,vibration mode and boundary conditions,on TED are examined in *** shows that TED decreases with the increases in the values of length scale parameters because the latter lead to the increase in structural stiffness.

关键词： Functionally graded material Size dependent Thermoelastic damping Micro-beam

Effects of chemical energy accommodation on nonequilibrium flow and heat transfer to a catalytic wall

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Chinese Journal of Aeronautics 2022年第10期35卷 165-175页

作者： Shunliang zhang Zhihui WANG School of Engineering Science University of Chinese Academy of SciencesBeijing 100049China

The accurate prediction of the aeroheating performance of hypersonic vehicles requires more detailed modeling of the catalysis process,rather than merely employing a catalytic *** this paper,the theoretical modeling,as well as the direct simulation Monte Carlo method,is used to preliminarily study the incomplete chemical energy accommodation effects,that is,only a part of the potential energy released in the heterogenous recombination reaction is transferred to the surface,while the remaining is retained as the vibrational energy of the desorbed *** integrated model is proposed to describe the contribution of each energy mode in the rarefied nonequilibrium heat and mass transfer *** on the model and several Damko?hler numbers,an analytical formula is derived,and is also shown to compare well with the numerical *** account of the incomplete accommodations of the chemical and vibrational energy on the wall,a variation up to 20%is observed in predicting the stagnation point heat flux under typical nonequilibrium flow *** study could enrich our understanding of the nonequilibrium heat transfer phenomenon and also shows a potential practical value.

关键词： Catalytic reaction Energy accommodation Heat transfer Nonequilibrium flow Stagnation point

Electronic origin of structural degradation in Li-rich transition metal oxides:The case of Li_(2)MnO_(3)and Li_(2)RuO_(3)

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Journal of Semiconductors 2024年第4期45卷 82-86页

作者： Peng zhang Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province College of Physics andOp toelec-tronic EngineeringShenzhen UniversityShenzhen 518060China

Li_(2)MnO_(3)and Li_(2)RuO_(3)represent two prototype Li-rich transition metal(TM)oxides as high-capacity cathodes for Li-ion batteries,which have similar crystal structures but show quite different cycling ***,based on the first-princi-ples calculations,we systematically studied the electronic structures and defect properties of these two Li-rich cathodes,in order to get more understanding on the structural degradation mechanism in Li-rich TM *** calculations indicated that the structural and cycling stability of Li_(2)MnO_(3)and Li_(2)RuO_(3)depend closely on their electronic structures,especially the energy of their highest occupied electronic states(HOS),as it largely determines the defect properties of these *** Li_(2)MnO_(3)with low-energy HOS,we found that,due to the defect charge transfer mechanism,various defects can form spontaneously in its host structure as Li ions are extracted upon delithiation,which seriously deteriorates its structural and cycling *** for Li_(2)RuO_(3),on the other hand,we identified that the high-energy HOS prevents it from the defect formation upon delithi-ation and thus preserve its cycling *** studies thus illustrated an electronic origin of the structural degradation in Li-rich TM oxides and implied that it is possible to improve their cycling performances by carefully adjusting their TM compo-nents.

关键词： defects Li-ion batteries first-principles calculations

Poisson-Arago spot for gravitational waves

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Science China(Physics,Mechanics & Astronomy) 2021年第12期64卷 2-7页

作者： HongSheng zhang XiLong Fan School of Physics and Technology University of JinanJinan 250022China School of Physics and Technology Wuhan UniversityWuhan 430072China

For the observer at infinity, a Schwarzschild black hole serves as an attractive opaque disk with a radius of 3√3 M that will produce the diffraction pattern of gravitational waves(GWs). In this study, we demonstrate that a bright spot, which is a diffraction effect analogous to the Poisson-Arago spot in optics, will appear when an ingoing(quasi-)plane GW is diffracted by a Schwarzschild black hole. Here, we propose the diffraction effect of the GWs described by the exact diffraction solution of the GWs using the Heun function. For the first time, the Fresnel half-wave zone method is proposed to calculate the angular part of the GW scattering stripes for the observer at infinity. The prospect of observing the diffraction bright spot is discussed with an eikonal approximation. For normal incidence(quasi)-plane waves with 100 Hz(0.1 Hz) frequency diffracted by the central black hole of the Milky Way, the time delay between the Earth bathed in a bright spot and the minimum of the first dark stripe is 3.86(3860) d. We will witness the second bright fringe(40% amplitude of the central bright spot) after 6.2(6200) d. This new diffraction pattern involving the early phase of inspirals and pulsars as continuous gravitational wave sources is a potential scientific target for future space-and ground-based gravitational wave detectors, respectively.

关键词： gravitational waves diffraction black hole

Interior-collapsing mechanism by hydrothermal process of the MgAl_(2)O_(4)/MgO porous ceramic

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Journal of Advanced Ceramics 2022年第5期11卷 814-824页

作者： Yao YAO Yue zhang Key Laboratory of Aerospace Materials and Performance(Ministry of Education) School of Materials Science and EngineeringBeihang UniversityBeijing 100191China

Ceramic core is a critical component in the super-alloy turbine blade *** our previous work,a novel multi-phase MgAl_(2)O_(4)/MgO porous ceramic was prepared for this *** most important property was that it crumbled completely after hydrothermal treatment in just pure water,due to the hydration of *** this work,the hydration process of the MgO embedded in the inert matrix was investigated in *** collapse behaved as an interior destruction without any bulk expansion of the *** hydration percentage was the only factor related to the *** morphology of hydration product indicated that the reaction advanced in particular *** on the finite element analysis for the expansion effect on the porous structure,the interiorcollapsing mechanism was *** the hydration process,the MgO grains exerted pressure to the surrounding matrix and induced the collapse in the adjacent *** process took place throughout the ***,the sample crumbled completely to the *** bulk dilatation was detected before the powdering,indicating that the collapse process would not exert pressure *** the alloy blade would not be damaged during the removal of the ceramic *** was also predicted that the decrease in the MgO grain size was beneficial to the water-collapsibility.

关键词： ceramic cores porous structure MgO hydration interior-collapsing mechanism

Impacts of heterogeneous CO_(2)on water and carbon fluxes across the global land surface

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International Journal of Digital Earth 2021年第9期14卷 1175-1193页

作者： Jing Tian Yongqiang zhang Xuanze zhang Key Laboratory of Water Cycle and Related Land Surface Processes Institute of Geographical Sciences and Natural Resources Research(IGSNRR)Chinese Academy of Sciences(CAS)BeijingPeople’s Republic of China

Over the recent decades,the increase of atmospheric carbon dioxide(CO_(2))concentration has caused large effects on the earth ***,few studies have paid attention to the effects of heterogeneity of CO_(2)on the biosphere and the *** a coupled diagnostic biophysical model(PML-V2)and comparing three heterogeneous CO_(2)datasets(GOSAT,CMIP6 and CarbonTracker)against a baseline homogeneous data(ESRL),this study investigated the effects of heterogeneous CO_(2)on gross primary production(GPP),actual evapotranspiration(ET)and water use efficiency(WUE)across the *** results show that among the three heterogeneity CO_(2),CarbonTracker produced the highest CO_(2)concentration and showed the largest difference in ET(−6%to 2%),GPP(−2%to 5%)and WUE(4%to 11%)compared to those from the *** most effects of the CO_(2)heterogeneity occurred in *** was identified as a vulnerable region with prominent decrease in GPP and an increase in ET due to CO_(2)*** obvious increase in GPP and a decrease in ET appeared in the Amazon rainforest,the Congo rainforest,and eastern *** global scale,the effects of the CO_(2)heterogeneity on ET/GPP/WUE were not significant.

关键词： Global CO_(2)heterogeneity evapotranspiration gross primary production water use efficiency