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Flow instability of supercritical hydrocarbon fuel in a multi-channel cooling system

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Chinese Journal of Aeronautics 2024年第2期37卷 283-295页

作者： Yichao JIN Kun WU Xuejun FAN Institute of applied Physics and Computational Mathematics Beijing 100094China Institute of Mechanics Chinese Academy of SciencesBeijing 100190China School of Engineering Science University of Chinese Academy of SciencesBeijing 100049China

Thermally-induced flow instabilities are a critical issue in multi-channel regenerative cooling *** particular,the interactions between Density-Wave Oscillations(DWO)and Flow Maldistribution(FMD)can result in complex and disastrous instability *** study investigates the instability behaviors of hydrocarbon fluid in a four-channel system with a constant heat flux ratio using both frequency-and time-domain *** the heat flux increases,the in-tube flow sequentially destabilizes in each channel and converges to new equilibrium states,leading to the emergence of FMD *** also causes the system eigenvalue to change repeatedly from negative to positive rather than increasing ***,the system eigenvalues are between those of the two most unstable channels,indicating that the stability behavior of the entire system is dictated by the most unstable *** FMD occurs,flow oscillations are activated in channels with weak stability,and the in-tube flow is observed to evolve into various flow patterns,including stable flow,self-sustained oscillation,oscillation divergence,quasiperiodic oscillation,and oscillation *** novel instability mode of oscillation excursion involves a spontaneous transition of operating *** oscillates from an equilibrium state and then stabilizes at a new operational state after oscillation-induced ***,the newfound stable state may also be only temporary,with the in-tube flow regressing to the initial state,resulting in quasi-periodic oscillation.

关键词： Cooling Supercritical fluids Hydrocarbons Flow instability Flow maldistribution Density-wave oscillations

Facile Synthesis of Polyisothioureas via Alternating Copolymerization of Aziridines and Isothiocayanates

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Chinese Journal of Polymer Science 2024年第3期42卷 292-298,I0005页

作者： Hao-Tian Zhang Ming-Xin Niu Qi Zhang Chen-Yang Hu Xuan Pang Key Laboratory of Polymer Ecomaterials Changchun Institute of Applied ChemistryChinese Academy of SciencesChangchun 130022China Department of Materials Science and Engineering Jilin UniversityChangchun 130025China School of applied Chemistry and Engineering University of Science and Technology of ChinaHefei 230026China

Isothiourea is an important class of sulfur-containing molecules showing unique catalytic and biological activities. As such,polyisothiourea is envisioned to be an interesting type of polymer that potentially exhibits a number of interesting properties. However, there is no access to synthesizing well-defined polyisothiourea, and currently isothiourea-containing polymers are mainly prepared by immobilizing onto other polymer's side chain. Herein, we report the first facile synthesis of polyisothioureas via alternating copolymerization of aziridines and isothiocayanates. Mediated by the catalytic system of phosphazene superbases/alcohol, a broad scope of aziridines and isothiocayanates could be transformed into polyisothioureas with adjustable substitutions(11 examples). The structures of obtained polyisothioureas were fully characterized with ^(1)H-NMR, ^(13)C-NMR, and ^(1)H-^(13)C HMBC NMR. Moreover, the polyisothioureas show tunable thermal properties depending on substitutions on the isothiourea linkages. The novel structure of these polyisothioureas will enable a powerful platform for the discovery of nextgeneration functional plastics.

关键词： Polyisothioureas Alternative copolymer Aziridines Isothiocayanates

Source localization based on field signatures:Laboratory ultrasonic validation

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Journal of Electronic Science and Technology 2024年第3期22卷 47-56页

作者： Mahmoud Eissa Dmitry Sukhanov Department of Radiophysics Tomsk State UniversityTomsk634050Russia Higher Institute for applied sciences and Technology(HIAST) Damascus31983Syria

Location awareness in wireless networks is essential for emergency services,navigation,gaming,and many other *** article presents a method for source localization based on measuring the amplitude-phase distribution of the field at the base *** existing scatterers in the target area create unique scattered field interference at each source *** unique field interference at each source location results in a unique field signature at the base station which is used for source *** the proposed method,the target area is divided into a grid with a step of less than half the *** grid node is characterized by its field signature at the base *** signatures corresponding to all nodes are normalized and stored in the base station as fingerprints for source *** normalization of the field signatures avoids the need for time synchronization between the base station and the *** a source transmits signals,the generated field signature at the base station is normalized and then correlated with the stored *** maximum correlation value is given by the node to which the source is the *** simulations and results of experiments on ultrasonic waves in the air show that the ultrasonic source is correctly localized using broadband field signatures with one base station and without time *** proposed method is potentially applicable for indoor localization and navigation of mobile robots.

关键词： Base station Field signature Fingerprints Localization Ultrasonic frequencies

Semi-analytical investigation of heat transfer in a porous convective radiative moving longitudinal fin exposed to magnetic field in the presence of a shape-dependent trihybrid nanofluid

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applied Mathematics and Mechanics(English Edition) 2024年第1期45卷 197-216页

作者： C.G.PAVITHRA B.J.GIREESHA M.L.KEERTHI Department of PG Studies and Research in Mathematics Kuvempu UniversityShankaraghatta 577451India Department of Mathematics and Statistics M.S.Ramaiah University of Applied SciencesBengaluru 560058India

The thermal examination of a non-integer-ordered mobile fin with a magnetism in the presence of a trihybrid nanofluid(Fe_3O_4-Au-Zn-blood) is carried out. Three types of nanoparticles, each having a different shape, are considered. These shapes include spherical(Fe_3O_4), cylindrical(Au), and platelet(Zn) configurations. The combination approach is utilized to evaluate the physical and thermal characteristics of the trihybrid and hybrid nanofluids, excluding the thermal conductivity and dynamic viscosity. These two properties are inferred by means of the interpolation method based on the volume fraction of nanoparticles. The governing equation is transformed into a dimensionless form, and the Adomian decomposition Sumudu transform method(ADSTM) is adopted to solve the conundrum of a moving fin immersed in a trihybrid nanofluid. The obtained results agree well with those numerical simulation results, indicating that this research is reliable. The influence of diverse factors on the thermal overview for varying noninteger values of γ is analyzed and presented in graphical representations. Furthermore, the fluctuations in the heat transfer concerning the pertinent parameters are studied. The results show that the heat flux in the presence of the combination of spherical, cylindrical, and platelet nanoparticles is higher than that in the presence of the combination of only spherical and cylindrical nanoparticles. The temperature at the fin tip increases by 0.705 759% when the value of the Peclet number increases by 400%, while decreases by 11.825 13% when the value of the Hartman number increases by 400%.

关键词： convection radiation moving longitudinal fin Adomian decomposition Sumudu transform method(ADSTM) trihybrid nanofluid magnetic field

A dysregulated calcium homeostasis as the earliest pathological sign in stem cell-derived Parkinson's disease neurons?

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Neural Regeneration Research 2024年第7期19卷 1421-1422页

作者： Nilima Prakash Working Group Human Stem Cell Research Department Hamm 2Hamm-Lippstadt University of Applied SciencesHammGermany

Parkinson’s disease(PD) is characterized by the slow and progressive demise of dopamine(DA)-synthesizing neurons in the substantia nigra pars compacta(SNc),a nucleus located in the human ventral *** death also affects other regions in the brain at later stages of *** concomitant lack of DA in the human forebrain(striatum) leads to the typical motor symptoms of this still uncurable neurodegenerative disorder.

关键词： homeostasis dopamine death

Key role of electron accessibility at the noble metal-free catalytic interface in hydrogen evolution reaction

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Nano Research 2024年第4期17卷 2538-2545页

作者： Dongchen Han Nanxing Gao Yuyi Chu Zhaoping Shi Ying Wang Junjie Ge Meiling Xiao Changpeng Liu Wei Xing State Key Laboratory of Electroanalytical Chemistry Changchun Institute of Applied ChemistryChinese Academy of SciencesChangchun 130022China School of applied Chemistry and Engineering University of Science and Technology of ChinaHefei 230026China Laboratory of Advanced Power Sources Changchun Institute of Applied ChemistryChinese Academy of SciencesChangchun 130022China Jilin Province Key Laboratory of Low Carbon Chemical Power Sources Changchun 130022China State Key Laboratory of Rare Earth Resource Utilization Changchun Institute of Applied ChemistryChinese Academy of SciencesChangchun 130022China

The reactant concentration at the catalytic interface holds the key to the activity of electrocatalytic hydrogen evolution reaction(HER),mainly referring to the capacity of adsorbing hydrogen and electron *** hydrogen adsorption free energy(ΔGH)as a reactivity descriptor,the volcano curve based on Sabatier principle is established to evaluate the hydrogen evolution activity of ***,the role of electron as reactant received insufficient attention,especially for noble metal-free compound catalysts with poor conductivity,leading to cognitive gap between electronic conductivity and apparent catalytic *** we successfully construct a series of catalyst models with gradient conductivities by regulating molybdenum disulfide(MoS_(2))electronic bandgap via a simple solvothermal *** demonstrate that the conductivity of catalysts greatly affects the overall catalytic *** further elucidate the key role of intrinsic conductivity of catalyst towards water electrolysis,mainly concentrating on the electron transport from electrode to catalyst,the electron accumulation process at the catalyst layer,and the charge transfer progress from catalyst to *** and experimental evidence demonstrates that,with the enhancement in electron accessibility at the catalytic interface,the dominant parameter governing overall HER activity gradually converts from electron accessibility to combination of electron accessibility and hydrogen adsorbing *** results provide the insight from various perspective for developing noble metal-free catalysts in electrocatalysis beyond HER.

关键词： conductivity molybdenum disulfide catalytic interface electron accessibility hydrogen evolution charge transfer.

Experimental Study on the Performance of ORC System Based on Ultra-Low Temperature Heat Sources

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Energy Engineering 2024年第1期121卷 145-168页

作者： Tianyu Zhou Liang Hao Xin Xu Meng Si Lian Zhang College of Mechanical Engineering Tianjin University of Science&TechnologyTianjin300222China School of Energy Engineering Tianjin Sino-German University of Applied SciencesTianjin300350China Tianjin“The Belt and Road”Joint Laboratory Tianjin Sino-German University of Applied SciencesTianjin300350China

This paper discussed the experimental results of the performance of an organic Rankine cycle(ORC)system with an ultra-low temperature heat *** low boiling point working medium R134a was adopted in the *** simulated heat source temperature(SHST)in this work was set from 39.51°C to 48.60°C by the simulated heat source *** influence of load percentage of simulated heat source(LPSHS)between 50%and 70%,the rotary valve opening(RVO)between 20%and 100%,the resistive load between 36Ωand 180Ωor the no-load of the generator,as well as the autumn and winter ambient temperature on the system performance were *** results showed that the stability of the system was promoted when the generator had a resistive *** power generation(PG)and generator speed(GS)of the system in autumn were better than in winter,but the expander pressure ratio(EPR)was lower than in *** RVO unchanged,the SHST,the mass flow rate(MFR)of the working medium,GS,and the PG of the system increased with the increasing of LPSHS for different generator resistance load *** the RVO was 60%,LPSHS was 70%,the SHST was 44.15°C and the resistive load was 72Ω,the highest PG reached 15.11 ***,a simulation formula was obtained for LPSHS,resistance load,and PG,and its correlation coefficient was between 0.9818 and *** formula can accurately predict the *** experimental results showed that the standard deviation between the experimental and simulated values was below 0.0792,and the relative error was within±5%.

关键词： ORC load percentage of simulated heat source resistive load rotary valve opening power generation

Phylogenetic, phylogeographic and divergence time analysis of Anopheles subpictus species complex using ITS2 and COI sequences

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Asian Pacific Journal of Tropical Medicine 2024年第5期17卷 214-225,I0004-I0038页

作者： Lihini Sandaleka Muthukumarana Methsala Madurangi Wedage Samanthika Rathnayake Nissanka Kolitha De Silva Department of Zoology Faculty of Applied SciencesUniversity of Sri JayewardenepuraGangodawilaNugegodaSri Lanka Genetics and Molecular Biology Unit Faculty of Applied SciencesUniversity of Sri JayewardenepuraGangodawilaNugegodaSri Lanka Sri Lanka Institute of Biotechnology PitipanaHomagamaSri Lanka

Objective:To address the phylogenetic and phylogeographic relationship between different lineages of Anopheles(An.)subpictus species complex in most parts of the Asian continent by maximum utilization of Internal Transcriber Spacer 2(ITS2)and cytochrome C oxidase I(COI)sequences deposited at the ***:Seventy-five ITS2,210 COI and 26 concatenated sequences available in the NCBI database were *** analysis was performed using Bayesian likelihood trees,whereas median-joining haplotype networks and time-scale divergence trees were generated for phylogeographic *** diversity indices and genetic differentiation were also ***:Two genetically divergent molecular forms of *** species complex corresponding to sibling species A and B are *** A evolved around 37-82 million years ago in Sri Lanka,India,and the Netherlands,and species B evolved around 22-79 million years ago in Sri Lanka,India,and ***,Thailand,and Cambodia have two molecular forms:one is phylogenetically similar to species *** forms differ from species A and B and evolved recently in the above mentioned countries,Indonesia and the *** subdivision among Sri Lanka,India,and the Netherlands is almost absent.A substantial genetic differentiation was obtained for some populations due to isolation by large geographical *** diversity indices reveal the presence of a long-established stable mosquito population,at mutation-drift equilibrium,regardless of population ***:*** species complex consists of more than two genetically divergent molecular *** A is highly divergent from the *** Lanka and India contain only species A and B.

关键词： Molecular systematics ITS2 COI DNA sequences Phylogeny Phylogeography

Differentially-grown cobalt regulators cooperatively involved in the tandem catalysis for high-yield production of second amines

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Nano Research 2024年第4期17卷 2444-2450页

作者： Jinhui Xu Xiao Wang Ying Wang Fei Wang Lingling Zhang Wenjie Cui Shuyan Song Hongjie Zhang State Key Laboratory of Rare Earth Resource Utilization Changchun Institute of Applied ChemistryChinese Academy of SciencesChangchun 130022China School of applied Chemistry and Engineering University of Science and Technology of ChinaHefei 230026China Department of Chemistry Tsinghua UniversityBeijing 100084China

One-pot tandem catalysis has been regarded as one of the most atomic economic ways to produce secondary amines,the important platform molecules for chemical synthesis and pharmaceutical manufacture,but it is facing serious issues in overall *** promotional effects are highly desired for boosting the activity and regulating the selectivity of conventional tandem *** this work,we report a high-performance tandem catalyst with maximized synergistic effect among each counterpart by preciously manipulating the spatial structure,which involves the active CeO_(2)/Pt component as kernel,the densely-coated N-doped C(NC)layer as selectivity controller,and the differentially-grown Co species as catalytic performance *** comprehensive investigations,the unique growth mechanism and the promotion effect of Co regulators are ***,the surface-landed Co clusters(Cocs)are crucial to selectivity by altering the adsorption configuration of benzylideneaniline ***,the inner Co particles(Cops)are essential for activity by denoting their electrons to neighboring *** from the unique promotion effect,a remarkably-improved catalytic efficiency(100%nitrobenzene conversion with 94%N-benzylaniline selectivity)is achieved at a relatively low temperature of 80℃,which is much better than that of CeO_(2)/Pt(100%nitrobenzene conversion with 12%N-benzylaniline selectivity)and CeO_(2)/Pt/NC(35%nitrobenzene conversion with 94%benzylideneaniline selectivity).

关键词： tandem catalysis CeO_(2) hierarchical structure heterogeneous catalyst dual-site materials