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Relationships between ionospheric parameters derived from ionosonde observations and characteristics of post-sunset GHz scintillation during high solar activities(2012−2013)at Sanya(18.3°n,109.6°E),China

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Earth and Planetary Physics 2023年第3期7卷 389-406页

作者： JunJie luo Ying Xiong WeiHua luo ZhengPing Zhu ChaoWan Fan College of Electronic and Information Engineering South-Central Minzu University430074 WuhanChina Hubei Key Laboratory of Intelligent Wireless Communications South-Central Minzu University430074 WuhanChina Hubei Engineering Research Center of Intelligent Internet of Things Technology South-Central Minzu University430074 WuhanChina

In this study,we present characteristics of post-sunset GHz scintillation occurrence and their correlations with ionospheric parameters derived from ionosonde observations in high solar activity years(2012−2013)of solar cycle 24 at Sanya(18.3°n,109.6°E;dip lat.:12.8°n),*** analyzed data include the F_(2)-layer’s critical frequency(foF_(2)),peak height(h_(m)F_(2)),and minimum virtual height(h’F),as well as the scale height around the F_(2)-layer peak(H_(m)),and virtual height(h’F_(5))and true height(hF_(5))measured at 5 *** have investigated relationships between the equinoctial asymmetry of these scintillations and these ionospheric *** addition,we calculate the growth rates of Rayleigh−Taylor instability on the basis of the ionosonde measurements and theoretical models,*** find that the equinoctial asymmetry of scintillation onset time is associated with the scale length of the vertical electron density gradient(L),which has been shown to affect the growth of Rayleigh−Taylor instability at the bottom of the *** seasonal variations of foF_(2),H_(m)and scale length of vertical electron density gradient appear to cause the seasonal variations of scintillation occurrence;the equinoctial asymmetry of scintillation occurrence rate over low latitudes appears to be related to background electron density and vertical drifts in the F-layer around time of *** study is required to explain the observed correlational weakness in low latitudes between scintillation strength,represented by the daily maximum S4,and daily maximum values of foF_(2),h_(m)F_(2),h’F,H_(m),and also the drifts.

关键词： equatorial ionosphere scintillation low latitude iononsonde equinoctial asymmetry

Comparative study on pressure swing adsorption system for industrial hydrogen and fuel cell hydrogen

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Chinese Journal of Chemical Engineering 2022年第2期35卷 112-119页

作者： Jian Chen Lingbing Bu Yingqi luo Southwest Institute of Chemical Co. Ltd.Chengdu 610225China

In order to improve the design of PSA system for fuel cell hydrogen production,a non-isothermal model of eight-bed PSA hydrogen process with five-component(H_(2)/n_(2)/CH_(4)/CO/CO_(2)=74.59%/0.01%/4.2%/2.5%/18.7%(vol))four-stage pressure equalization was developed in this *** model adopts a composite adsorption bed of activated carbon and zeolite 5 *** this article,pressure variation,temperature field and separation performance are stimulated,and also effect of providing purge(PP)differential pressure and the ratio of activated carbon to zeolite 5 A on separation performance in the process of producing industrial hydrogen(CO content in hydrogen is 10μl·L^(-1))and fuel cell hydrogen(CO content is 0.2μl·L^(-1))are *** results show that Run 3,when the CO content in hydrogen is 10μl·L^(-1),the hydrogen recovery is 89.8%,and the average flow rate of feed gas is 0.529 mol·s^(-1);When the CO content in hydrogen is 0.2μl·L^(-1),the hydrogen recovery is 85.2%,and the average flow rate of feed gas is 0.43 mol·s^(-1).With the increase of PP differential pressure,hydrogen recovery first increases and then decreases,reaching the maximum when PP differential pressure is 0.263 MPa;With the decrease of the ratio of activated carbon to zeolite 5 A,the hydrogen recovery increases *** the CO content in hydrogen is 0.2μl·L^(-1) the hydrogen recovery increases more obviously,from 83.96%to 86.37%,until the ratio of activated carbon to zeolite 5 A decreases to *** the end of PP step,no large amount of CO_(2) in gas or solid phase enters the zeolite 5 A adsorption bed,while when the CO content in hydrogen is 10μl·L^(-1),and the ratio of carbon to zeolite 5 A is less than 1.4,more CO_(2) will enter the zeolite 5 A bed.

关键词： Pressure swing adsorption Hydrogen Fuel cell hydrogen Industrial hydrogen numerical simulation

Magnetic Interactions and Band Gaps of the(CrO_(2))_(2)/(MgH_(2))_(n) Superlattices

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Chinese Physics Letters 2022年第11期39卷 57-62页

作者： Wanfei Shan Jiangtao Du Weidong luo Key Laboratory of Artificial Structures and Quantum Control(Ministry of Education) School of Physics and AstronomyShanghai Jiao Tong UniversityShanghai 200240China Institute of natural Sciences Shanghai Jiao Tong UniversityShanghai 200240China

Lattice superlattices constructed with different materials such as ferromagnets and insulators at atomic scale provide an ideal platform for exploring many emergent physical *** the present work,a new type of superlattices composed of ferromagnetic half-metal CrO_(2),with a thickness of two atomic layers,together with insulating MgH_(2) are *** theoretical studies on the(CrO_(2))_(2)/(MgH_(2))_(n) (n=2,3,4,5,6)superlattices are carried out based on first-principles density-functional theory *** superlattices are ferromagnetic semiconductors with similar intra-layer magnetic exchange couplings between Cr *** the thickness of the MgH_(2) layer increases,the magnetic exchange interaction between inter-layer Cr ions shows oscillating decaying behavior,while the energy band gaps show a small *** understanding of magnetic couplings in these superlattices provides a pathway for constructing new ferromagnetic semiconductors.

关键词： ferromagnetic coupling layer

nitrogen reduction reaction on small iron clusters supported by n-doped graphene:A theoretical study of the atomically precise active-site mechanism

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nano Research 2020年第8期13卷 2280-2288页

作者： Chaonan Cui Hongchao Zhang Zhixun luo Beijing national Laboratory for Molecular Sciences(BnLMS) State Key Laboratory for Structural Chemistry of Unstable and Stable SpeciesInstitute of ChemistryChinese Academy of SciencesBeijing100190China University of Chinese Academy of Sciences Beijing100049China

nonprecious metal catalysts are known of significance for electrochemical n2 reduction reaction(nRR)of which the mechanism has been illustrated by ongoing investigations of single atom ***,it remains challenging to fully understand the size-dependent synergistic effect of active sites inherited in substantial *** this work,four types of small iron clusters Fen(n=1–4)supported on nitrogen-doped graphene sheets are constructed to figure out the size dependence and synergistic effect of active sites for nRR catalytic *** is revealed that Fe3 and Fe4 clusters on n4G supports exhibit higher nRR activity than single-iron atom and iron dimer clusters,showing lowered limiting potential and restricted hydrogen evolution reaction(HER)which is a competitive reaction *** particular,the Fe4-n4G displays outstanding nRR performance for“side-on”adsorption of n2 with a small limiting potential(−0.45 V).Besides the specific structure and strong interface interaction within the Fe4-n4G itself,the high nRR activity is associated with the unique bonding/antibonding orbital interactions of n-n and n-Fe for the adsorptive n2 and nnH intermediates,as well as relatively large charge transfer between n2 and the cluster Fe4-n4G.

关键词： n2 reduction reaction(nRR) iron clusters cluster catalysis active-site mechanism density functional theory(DFT)

The removal of inevitable nOx species in catalysts and the selection of appropriate membrane for measuring electrocatalytic ammonia synthesis accurately

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Journal of Energy Chemistry 2020年第10期29卷 51-58页

作者： Huimin Liu Yidan Zhang Jingshan luo Institute of Photoelectronic Thin Film Devices and Technology Key Laboratory of Photoelectronic Thin Film Devices and Technology of TianjinMinistry of Education Engineering Research Center of Thin Film Photoelectronic TechnologyRenewable Energy Conversion and Storage CenterNankai UniversityTianjin 300350China

Ammonia synthesis by electrocatalytic nitrogen reduction reaction(nRR)is considered as a promising alternative to the Haber−Bosch ***,due to the extremely low ammonia yield and easily accessible extraneous contamination in the laboratory,nRR study always suffers from fluctuation and *** and eliminating all kinds of possible extraneous contamination is crucial to evaluate the performance of electrocatalytic ammonia synthesis *** this work,we systematically explored two factors that affect nRR results but are easy to be ignored:the selection of membrane for nRR and the unconscious n-source in nRR *** series of experiments,we proposed a low-cost and almost pollution-free Celgard 3501 membrane as the separator for nRR to avoid the adsorption and release of ammonia by the *** addition,we proposed a pre-reduction strategy to remove residual or adsorbed nOx contaminants in *** two solutions will help the community to evaluate the nRR activity more accurately.

关键词： Electrocatalysis nitrogen reduction reaction nafion membrane nitrate impurity Pre-reduction

Micro/atomic-scale vibration induced superlubricity

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Friction 2021年第5期9卷 1163-1174页

作者： Shuai SHI Dan GUO Jianbin luo State Key Laboratory of Tribology Tsinghua UniversityBeijing 100084China China Fortune Land Development Industrial Investment Co. Ltd.Beijing 100027China

With the rapid development of industry,the inconsistency between the rapid increase in energy consumption and the shortage of resources is becoming *** is one of the main causes of energy consumption;thus,the emergence of superlubricity technology can substantially improve the energy efficiency in motion *** this study,an efficient method to control superlubricity at the atomic‐scale is *** method employs vibrational excitation,which is called vibration induced superlubricity(VIS).The VIS can be easily and steadily achieved by employing external vibration in three *** simple method does not depend on the type of sample and *** of oscillation amplitude,frequency,scanning speed,and normal force(F_(n))on friction were *** and simulated explorations verified the practical approach for reducing energy dissipation and achieving superlubricity at the atomic‐scale.

关键词： superlubricity atomic‐scale vibration energy dissipation

State-of-the-art progress in overall water splitting of carbon nitride based photocatalysts

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Frontiers in Energy 2021年第3期15卷 600-620页

作者： Bing luo Yuxin ZHAO Dengwei JInG School of Chemical Engineering and Technology Xi’an Jiaotong UniversityXi’an 710049China International Research Center for Renewable Energy and State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong UniversityXi’an 710049China

Converting solar energy into hydrogen(H_(2))by photocatalytic water splitting is a promising approach to simultaneously address the increasing energy demand and environmental *** decade has passed since the discovery of photo-induced water splitting phenomenon on TiO_(2)photoanode,while the solar to H_(2) efficiency is still around 1%,far below the least industrial ***,developing efficient photocatalyst with a high energy conversion efficiency is still one of the main tasks to be *** carbon nitride(g-C_(3)n_(4))is just such an emerging and potential ***,in this review,the state-of-the-art advances in g-C_(3)n_(4)based photocatalysts for overall water splitting were summarized in three sections according to the strategies used,and future challenges and new directions were discussed.

关键词： photocatalysis overall water splitting carbon nitride hydrogen

Refrigeration system synthesis based on de-redundant model by particle swarm optimization algorithm

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Chinese Journal of Chemical Engineering 2022年第10期50卷 412-422页

作者： Danlei Chen Yiqing luo Xigang Yuan School of Chemical Engineering and Technology Tianjin UniversityTianjin 300072China State Key Laboratory of Chemical Engineering Tianjin UniversityTianjin 300072China

Simultaneous optimization of refrigeration system(RS)and its heat exchanger network(HEn)leads to a large-scale non-convex mixed-integer non-linear programming(MInLP)***,researchers usually adopted simplifications to confine problem scale from being too large at the cost of reducing solution *** study established an optimization framework for the simultaneous optimization of RS and ***,A more comprehensive and compact model was developed to guarantee a relatively complete solution space while reducing model scale as well as its solving *** this model,a tandem arrangement of connecting sub-coolers and expansion valves was considered in the superstructure;and the pressure/temperature levels were optimized as continuous *** this basis,we proposed a"two-step transformation method"to equivalently transform the cross-level structure into a no n-cross-level structu re,and the de-redundant superstructu re was established with ensuring comprehensiveness and ***,the MInLP model was developed and solved by Particle Swarm Optimization ***,our methodology was validated to get better optimal results with less CPU time in two case studies,an ethylene RS in an existing plant and a reported propylene RS.

关键词： Refrigeration system Optimal design Process systems Particle swarmoptimization Mathematical modeling

Selective production of acetol or methyl lactate from cellulose over RuSn catalysts

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Journal of Energy Chemistry 2022年第10期31卷 607-614,I0015页

作者： Dawang Chu Zhicheng luo Chen Zhao Shanghai Key Laboratory of Green Chemistry and Chemical Processes School of Chemistry and Molecular EngineeringEast China Normal UniversityShanghai 200062China Institute of Eco-Chongming Shanghai 202162China

Designing a catalytic system that could convert cellulose to switchable C3 alcohols or esters with controllable selectivity is highly desired to meet the rapidly changing market ***,we develop RuSn catalysts with the altering Sn loadings that can achieve acetol formation from cellulose hydrogenation at240℃in presence of H_(2)or yield methyl lactate production from cellulose conversion in methanol and water mixture at 200℃in presence of n_(2).The increased Sn contents from 3%to 6%lead to form different surface sites from Ru_(3)Sn_(7),Ru,and SnO_(x)to Ru_(3)Sn_(7)and SnO_(x).The integrated Ru_(3)Sn_(7),Ru,and SnO_(x)species on 1.5%Ru-3%Sn/SiO_(2)catalyze isomerization,retro-aldol condensation,and hydrogenation individual steps with coordinated reaction rates,resulting in the acetol formation with a high yield of 53.7 C%.Furthermore,the optimum combination of Ru_(3)Sn_(7)and SnO_(x)on 1.5%Ru-6%Sn/SiO_(2)contributes to the isomerization,retro-aldol condensation,dehydration,and 1,2-hydride shift,giving rise to the preferential production of methyl lactate at a 25.1 C%*** results illustrate the feasibility of controlling the selective conversion of cellulose to C3 acetol or methyl lactate by devising a tunable catalytic system,which guides the rational design of catalysts for the selective conversion of cellulose.

关键词： Cellulose conversion RuSn catalysts Methyl lactate Acetol Switchable production