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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

Simultaneous purification of minor components in natural products using twin-column recycling chromatography with a step solvent gradient

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Chinese Journal of Chemical Engineering 2024年第5期69卷 212-219页

作者： Guangxia jin Yuxue Wu Feng Wei School of Biological and Chemical Engineering NingboTech UniversityNingbo 315100China

The isolation of minor components from complex natural product matrices presents a significant challenge in the field of purification science due to their low concentrations and the presence of structurally similar *** study introduces an optimized twin-column recycling chromatography method for the efficient and simultaneous purification of these elusive *** introducing water at a small flowing rate between the twin columns,a step solvent gradient is created,by which the leading edge of concentration band would migrate at a slower rate than the trailing edge as it flowing from the upstream to downstream ***,the band broadening is counterbalanced,resulting in an enrichment effect for those minor components in separation ***,two target substances,which showed similar peak position in high performance liquid chromatography(HPLC)and did not exceed 1.8%in crude paclitaxel were selected as target compounds for *** using the twin-column recycling chromatography with a step solvent gradient,a successful purification was achieved in getting the two with the purity almost 100%.We suggest this method is suitable for the separation of most components in natural produces,which shows higher precision and recovery rate compared with the common lab-operated separation ways for natural products(thin-layer chromatography and prep-HPLC).

关键词： Solvent gradient Twin-column recycling chromatography Purification Minor component Natural products

The twisted conical Kahler-Ricci solitons on Fano manifolds

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Science China Mathematics 2024年第5期67卷 1085-1102页

作者： Xishen jin Jiawei Liu School of Mathematics Renmin University of ChinaBeijing 100872China School of Mathematics and Statistics Nanjing University of Science&TechnologyNanjing 210094China

In this paper,we show the relation between the existence of twisted conical K?hler-Ricci solitons and the greatest log Bakry-Emery-Ricci lower bound on Fano *** is based on our proofs of some openness theorems on the existence of twisted conical Kahler-Ricci solitons,which generalize Donaldson’s existence conjecture and the openness theorem of the conical K?hler-Einstein metrics to the conical soliton case.

关键词： greatest log Bakry-Emery-Ricci lower bound twisted conical Kahler-Ricci soliton twisted Kahler-Ricci soliton

Improved lower bound for the complexity of unique shortest vector problem

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Cybersecurity 2024年第3期7卷 102-110页

作者： Baolong jin Rui Xue State Key Laboratory of Information Security Institute of Information EngineeringChinese Academy of SciencesBeijing 100085China School of Cyber Security University of Chinese Academy of SciencesBeijing 100049China

Unique shortest vector problem(uSVP)plays an important role in lattice based *** cryptographic schemes based their security on *** the cofidence of those applications,it is essential to clarify the complex-ity of uSVP with different ***,proving the NP-hardness of usVP appears quite *** the state of the art,we are even not able to prove the NP-hardness of usVP with constant *** this work,we gave a lower bound for the hardness of usVP with constant parameters,*** proved that uSVP is at least as hard as gap shortest vector problem(GapSVP)with gap of O(√n/log(n)),which is in NP n *** previous works,our reduction works for paramters in a bigger range,especially when the constant hidden by the big-O in GapsVP is smallerthan1.

关键词： Computational complexity Unique shortest vector problem Bounded distance decoding Complexity reduction

An Improved Bounded Conflict-Based Search for Multi-AGV Pathfinding in Automated Container Terminals

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Computer Modeling in Engineering & Sciences 2024年第6期139卷 2705-2727页

作者： Xinci Zhou jin Zhu Shanghai Maritime University Logistics Science and Engineering Research InstituteShanghai200000China

As the number of automated guided vehicles(AGVs)within automated container terminals(ACT)continues to rise,conflicts have becomemore *** point and edge conflicts ofAGVs,amulti-AGVconflict-free path planning model has been formulated to minimize the total path length of AGVs between shore bridges and *** larger terminalmaps and complex environments,the grid method is employed to model AGVs’road *** improved bounded conflict-based search(IBCBS)algorithmtailored to ACT is proposed,leveraging the binary tree principle to resolve conflicts and employing focal search to expand the search *** experiments involving 60 AGVs indicate a reduction in computing time by 37.397%to 64.06%while maintaining the over cost within 1.019%.Numerical experiments validate the proposed algorithm’s efficacy in enhancing efficiency and ensuring solution quality.

关键词： Automated terminals multi-AGV multi-agent path finding(MAPF) conflict based search(CBS) AGV path planning

MD Simulation of Diffusion Behaviors in Collision Welding Processes of Al-Cu, Al-Al, Cu-Cu

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Computers, Materials & Continua 2024年第6期79卷 3455-3468页

作者： Dingyi jin Guo Wei School of Intelligent Manufacturing Hunan First Normal UniversityChangsha410082China School of Physics and Technology Center for Ion Beam ApplicationHubei Nuclear Solid Physics Key LaboratoryWuhan UniversityWuhan430072China

To investigate the effects of material combinations and velocity conditions on atomic diffusion behavior near collision interfaces,this study simulates the atomic diffusion behavior near collision interfaces in Cu-Al,Al-Al and Cu-Cu combinations fabricated through collision welding using molecular dynamic(MD)*** atomic diffusion behaviors are compared between similar metal combinations(Al-Al,Cu-Cu)and dissimilar metal combinations(Al-Cu).By combining the simulation results and classical diffusion theory,the diffusion coefficients for similar and dissimilar metal material combinations under different velocity conditions are *** effects of material combinations and collision velocity on diffusion behaviors are also *** diffusion behaviors of dissimilar material combinations strongly depend on the transverse velocity,whereas those of the similar material combinations are more dependent on the longitudinal *** findings can provide guidance for optimizing welding parameters.

关键词： Atomic diffusion behavior molecular dynamics collision welding

Oxidation behavior of low-grade vanadiferous titanomagnetite concentrate with high titanium

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Journal of Iron and Steel Research International 2024年第2期31卷 329-341页

作者： jin-sheng Liu Zhen-xing Xing Gong-jin Cheng Xue-yong Ding Xiang-xin Xue School of Metallurgy Northeastern UniversityShenyang110819LiaoningChina Liaoning Key Laboratory of Recycling Science for Metallurgical Resources Shenyang110819LiaoningChina Innovation Research Institute of Vanadium and Titanium Resource Industry Technology Northeastern UniversityShenyang110819LiaoningChina

In order to clarify the oxidation mechanisms and make better use of the low-grade vanadiferous titanomagnetite concentrate with high titanium(LVTC),the oxidation behavior of LVTC was *** results showed that oxidation degree was achieved within 90 min when temperature was not lower than 700°C,and the main phases of the oxidized LVTC consisted of Fe9TiO15,Fe2O3,CaSiTiO5 and a small amount of *** temperature is favorable to the formation of *** surface of LVTC gradually becomes rough,with fine particles of needle-like and granular shape appearing on the surface,which finally turn from laminar to creamy,spread out,and are interspersed with many tiny *** phase oxidation paths in LVTC were as follows:(1)Fe2.75Ti0.25O4→Fe9TiO15+Fe2O3;(2)Fe2.75Ti0.25O4→Fe2O3+FeTiO3→Fe2TiO5;(3)FeTiO3→Fe2O3+Fe2Ti3O9→*** is predominantly mesoporous whether oxidized or not,with the pores mainly distributed in the range of 2–40 nm,and the specific surface area of LVTC decreases significantly with increasing temperature.

关键词： Low-grade vanadiferous titanomagnetite concentrate Oxidation degree Phase transformation Micromorphology Oxidation path Pore structure

High-order Soliton Matrix for the Third-order Flow Equation of the Gerdjikov-Ivanov Hierarchy Through the Riemann-Hilbert Method

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Acta Mathematicae Applicatae Sinica 2024年第2期40卷 358-378页

作者： jin-yan ZHU Yong CHEN School of Mathematical Sciences Shanghai Key Laboratory of Pure Mathematics and Mathematical PracticeEast China Normal UniversityShanghai 200062China College of Mathematics and Systems Science Shandong University of Science and TechnologyQingdao 266590China

The Gerdjikov-Ivanov(GI)hierarchy is derived via recursion operator,in this article,we mainly investigate the third-order flow GI *** the framework of the Riemann-Hilbert method,the soliton matrices of the third-order flow GI equation with simple zeros and elementary high-order zeros of Riemann-Hilbert problem are constructed through the standard dressing *** advantage of this result,some properties and asymptotic analysis of single soliton solution and two soliton solution are discussed,and the simple elastic interaction of two soliton are *** with soliton solution of the classical second-order flow,we find that the higher-order dispersion term affects the propagation velocity,propagation direction and amplitude of the ***,by means of a certain limit technique,the high-order soliton solution matrix for the third-order flow GI equation is derived.

关键词： Gerdjikov-Ivanov hierarchy third-order flow GI equation Riemann-Hilbert method high-order soliton

Toxicity of the disinfectant benzalkonium chloride(C_(14))towards cyanobacterium Microcystis results from its impact on the photosynthetic apparatus and cell metabolism

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Journal of Environmental Sciences 2024年第1期135卷 198-209页

作者： Yunlu Jia Yi Huang jin Ma Shangwei Zhang jin Liu Tianli Li Lirong Song Institute of Hydrobiology Chinese Academy of SciencesWuhan 430072China School of Environmental Studies China University of GeosciencesWuhan 430074China Advanced Interdisciplinary Institute of Environment and Ecology Beijing Normal UniversityZhuhai 519087China

Quaternary ammonium compounds(QACs)are commonly used in a variety of consumer and commercial products,typically as a component of *** the COVID-19 pandemic,QACs became one of the primary agents utilized to inactivate the SARS CoV-2 virus on ***,the ecotoxicological effects of QACs upon aquatic organisms have not been fully *** this study,we examined the effects of a widely used QAC(benzalkonium chloride-C_(14),BAC-14)on two toxigenic Microcystis strains and one non-toxigenic freshwater Microcystis strain and carried out an analysis focused on primary,adaptive and compensatory stress responses at apical(growth and photosynthesis)and metabolic *** analysis revealed that the two toxic Microcystis strains were more tolerant than the non-toxic strain,with 96 hr-EC_(50)values of 0.70,0.76,and 0.38 mg/L BAC-14 for toxigenic *** FACHB-905,toxigenic *** FACHB-469,and non-toxigenic *** FACHB-908,*** photosynthetic activities of the Microcystis,assessed via F_(v)/F_(m) values,were significantly suppressed under 0.4 mg/L ***,this analysis revealed that BAC-14 altered 14,12,and 8 metabolic pathways in *** FACHB-905,*** FACHB-469,and *** FACHB-908,*** is noteworthy that BAC-14 enhanced the level of extracellular microcystin production in the toxigenic Microcystis strains,although cell growth was not significantly ***,these data show that BAC-14 disrupted the physiological and metabolic status of Microcystis cells and stimulated the production and release of microcystin,which could result in damage to aquatic systems.

关键词： Disinfectants Quaternary ammonium compounds Microcystis Cyanotoxin Metabolomics Chlorophyll fluorescence