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Bifurcation analysis and control study of improved full-speed differential model in connected vehicle environment

Chinese Physics B 2024年第7期33卷 245-266页

作者：艾文欢雷正清李丹洋方栋梁刘大为 college of Computer Science and engineering Northwest Normal UniversityLanzhou 730070China college of Electrical engineering Lanzhou Institute of TechnologyLanzhou 730050China

In recent years, the traffic congestion problem has become more and more serious, and the research on traffic system control has become a new hot spot. Studying the bifurcation characteristics of traffic flow systems and designing control schemes for unstable pivots can alleviate the traffic congestion problem from a new perspective. In this work, the full-speed differential model considering the vehicle network environment is improved in order to adjust the traffic flow from the perspective of bifurcation control, the existence conditions of Hopf bifurcation and saddle-node bifurcation in the model are proved theoretically, and the stability mutation point for the stability of the transportation system is found. For the unstable bifurcation point, a nonlinear system feedback controller is designed by using Chebyshev polynomial approximation and stochastic feedback control method. The advancement, postponement, and elimination of Hopf bifurcation are achieved without changing the system equilibrium point, and the mutation behavior of the transportation system is controlled so as to alleviate the traffic congestion. The changes in the stability of complex traffic systems are explained through the bifurcation analysis, which can better capture the characteristics of the traffic flow. By adjusting the control parameters in the feedback controllers, the influence of the boundary conditions on the stability of the traffic system is adequately described, and the effects of the unstable focuses and saddle points on the system are suppressed to slow down the traffic flow. In addition, the unstable bifurcation points can be eliminated and the Hopf bifurcation can be controlled to advance, delay, and disappear,so as to realize the control of the stability behavior of the traffic system, which can help to alleviate the traffic congestion and describe the actual traffic phenomena as well.

关键词： bifurcation analysis vehicle queuing bifurcation control Hopf bifurcation

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Prediction of liquid circulation flow rate in RH degasser:improvement of decarburization at low atmospheric pressure

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Journal of Iron and Steel Research International 2024年第7期31卷 1661-1667页

作者： Gu-jun Chen Sheng-ping He college of Materials Science and engineering Yangtze Normal UniversityChongqing 400044China college of Materials Science and engineering Chongqing UniversityChongqing 400044China

The two-fluid model coupled with population balance model was used for simulating the gas-liquid flow in the Ruhrstahl-Heraeus(RH)*** predicted circulation flow rate was compared with that measured from a water model experiment to validate the mathematical ***,influence of snorkel immersion depth on liquid circulation flow rate was numerically investigated under an atmospheric pressure of 101 and 84 kPa,*** result indicates that the circulation flow rate of the RH degasser in the high-altitude area was severely reduced because of the decrease in atmospheric ***,increasing the snorkel immersion depth from 0.5 to 0.7 m can compensate for the decrease in atmospheric *** test result indicates that decarburization rate is significantly enhanced by increasing the snorkel immersion *** optimization,the percentage of heats with a final carbon content less than 0.002 wt.%is significantly increased from 22.0%to 96.4%.

关键词： RH degasser Two-fluid model Population balance model-Circulation flow rate Decarburization Snorkel immersion depth

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Crystalline-amorphous M@MN_x(M=Co,Fe,Ni)encapsulated in nitrogen-doped carbon for enhanced efficient and durable hydrogen evolution reaction

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Rare Metals 2024年第4期43卷 1547-1556页

作者： Yang Yang Xiao-Chuan Duan Shao-Hui Guo Xian-Ming Zhang college of Materials Science and engineering College of ChemistryKey Laboratory of Interface Science and Engineering in Advanced MaterialsTaiyuan University of TechnologyYuci030600China

Developing earth-abundant electrocatalysts for hydrogen evolution reaction(HER)is important for the sustainable energy ***,efficient and stable heterocatalysts consisting of crystalline-amorphous M@MN_(x)(M=Co,Fe,Ni)encapsulated in N-doped carbon layers supported with N-doped graphene sheets(denoted as M@MN_(x)@NC-NG)are synthesized by facile hydrothermal reaction and nitridation *** the nitriding process,metal ions in M(tzbc)_2(H_(2)O)_4(tzbc=4-(1H-1,2,4-triazol-1-yl)benzoic acid)complexes are reduced to crystalline M cores,accompanied by the formation of amorphous MN_(x)shells;the tzbc ligands are insitu carbonized to form outermost N-doped carbon(NC)layers that connect with inner MN_(x)via M-N-C motifs inherited from the complex precursors and inhibit the transition of MN_(x)from amorphous to crystalline *** Co@CoN_(x)@NC-NG catalyst exhibits excellent HER activity with small overpotentials of 45 and 64 mV at a cathode current density of 10 mA·cm^(-2)and low Tafel slopes of 40 and 85 mV·dec^(-1)in 0.5 mol·L^(-1)H_(2)SO_4 and1.0 mol·L^(-1)KOH electrolytes,*** Co@CoN_(x)@NC-NG retains 97%of the initial overpotential after 100,000 s in both acidic and alkaline *** outstanding HER performance originates from the crystalline-amorphous Co@CoN_(x)that redistributes electrons around the heterointerfaces,facilitating the conversion process of H^(+)/H_(2)O to hydrogen and thereby promoting HER *** outermost NC layers serve as the armor of Co@CoN_(x),and graphene nanosheets act as carriers of egg-like Co@CoN_(x)@NC and conduction paths for electron shuttles,ensuring stable and continuous electrocatalytic hydrogen production.

关键词： Hydrogen evolution reaction Electrocatalysts Iron group metals Heterojunction Crystalline-amorphous structure

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Tailoring crystallization zinc hydroxide sulfates growth towards stable zinc deposition chemistry

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Nano Research 2024年第6期17卷 5243-5250页

作者： Kaixin Huang Xianguang Zeng Dan Zhang Yujie Wang Mu Lan Chengyan Wen Yi Guo college of Materials Science and engineering Sichuan University of Science and EngineeringZigong 643000China Department of Chemistry College of Resource and EnvironmentBaoshan UniversityBaoshan 678000China college of Optoelectronic engineering Chengdu University of Information TechnologyChengdu 610225China

The unstable zinc anode/electrolyte interface induced by corrosion,interfacial water splitting reaction,and dendrite growth seriously degrades the performances of metal Zn anode in aqueous ***,the nucleation and growth of zinc hydroxide sulfate(ZHS),an interfacial by-product,has been tailored by Tween 80 in the electrolyte,which thereby assists in in-situ forming a dense solid electrolyte interphase(SEI)with small-sized ZHS and evenly distributed Tween *** SEI has high corrosion resistance and uniform distribution of zinc ions,which not only contributes to blocking the interfacial side reactions but also induces stable and calm zinc plating/***,the modified electrolyte can confer the assembled Zn||Zn symmetric cell with a stable operation life over 1500 h at 1 mA·cm^(−2)and 1 mAh·cm^(−2)as well as the practical Zn||NH4V4O10 full battery with a high-rate capacity of 120 mAh·g^(−1)at the current density of 5 A·g^(−1).This work provides a way for regulating and reusing interfacial by-products,and a new sight on stabilization electrodes/electrolyte interfaces.

关键词： zinc hydroxide sulfides tailoring crystallization in-situ solid electrolyte interphase electrolyte engineering strategy aqueous zinc-ion battery

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Glutamicibacter nicotianae AT6:A new strain for the efficient biodegradation of tilmicosin

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Journal of Environmental Sciences 2024年第8期142卷 182-192页

作者： Huijuan Li Hao Zhou Liling Fan Long Meng Yanyun Zhao Lanmei Zhao Bo Wang college of Chemical and Biological engineering Shandong University of Science and TechnologyQingdao 266590China college of Chemistry and Chemical engineering Heze UniversityHeze 274015China college of Safety and Environmental engineering Shandong University of Science and TechnologyQingdao 266590China

The degradation of tilmicosin(TLM),a semi-synthetic 16-membered macrolide antibiotic,has been receiving increasing ***,there are three tilmicosin degradation methods,and among them microbial degradation is considered the best due to its high efficiency,eco-friendliness,and low ***,we found a new strain,Glutamicibacter nicotianae ***6,capable of degrading high-concentration TLM at 100 mg/L with a 97%removal *** role of tryptone was as well investigated,and the results revealed that the loading of tryptone had a significant influence on TLM *** toxicity assessment indicated that strain AT6 could efficiently convert TLM into less-toxic *** on the identified intermediates,the degradation of TLM by AT6 processing through two distinct pathways was then proposed.

关键词： Tilmicosin Glutamicibacter nicotianae Biodegradation Degradation pathway Pharmaceutical wastewater

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An application of a genetic algorithm in co-optimization of geological CO_(2)storage based on artificial neural networks

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Clean Energy 2024年第1期8卷 111-125页

作者： Pouya Vaziri Behnam Sedaee Institute of Petroleum engineering Chemical Engineering DepartmentCollege of EngineeringUniversity of TehranTehranIran

Global warming,driven by human-induced disruptions to the natural carbon dioxide(CO_(2))cycle,is a pressing *** mitigate this,carbon capture and storage has emerged as a key strategy that enables the continued use of fossil fuels while transitioning to cleaner energy *** saline aquifers are of particular interest due to their substantial CO_(2)storage potential,often located near fossil fuel *** this study,a deep saline aquifer model with a saline water production well was constructed to develop the optimization *** to the time-consuming nature of each realization of the numerical simulation,we introduce a sur-rogate aquifer model derived from extracted *** novelty of our work lies in the pioneering of simultaneous optimization using machine learning within an integrated *** previous studies,which typically focused on single-parameter optimiza-tion,our research addresses this gap by performing multi-objective optimization for CO_(2)storage and breakthrough time in deep sa-line aquifers using a data-driven *** methodology encompasses preprocessing and feature selection,identifying eight pivotal *** metrics include root mean square error(RMSE),mean absolute percentage error(MAPE)and R^(2).In predicting CO_(2)storage values,RMSE,MAPE and R^(2)in test data were 2.07%,1.52%and 0.99,respectively,while in blind data,they were 2.5%,2.05%and *** the CO_(2)breakthrough time,RMSE,MAPE and R^(2)in the test data were 2.1%,1.77%and 0.93,while in the blind data they were 2.8%,2.23%and 0.92,*** addressing the substantial computational demands and time-consuming nature of coup-ling a numerical simulator with an optimization algorithm,we have adopted a strategy in which the trained artificial neural network is seamlessly integrated with a multi-objective genetic *** this framework,we conducted 5000 comprehensive experi-ments to rigorously validate the development of the Pareto f

关键词： carbon capture and storage deep saline aquifer artificial neural network multi-objective optimization genetic algorithm breakthrough time geological storage

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Experimental investigation of surfactant adsorption during EOR and soil pollution control processes:Influence of surfactant concentration,water salinity,and clay type

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Petroleum 2024年第3期10卷 527-538页

作者： Arian Pishkoo Behnam Sedaee Alireza Bahramian Institute of Petroleum engineering Chemical Engineering DepartmentCollege of EngineeringUniversity of TehranTehranIran

Surfactant injection is a well-established method of chemical EOR *** adsorption into clay layers can prevent their proper performance and thus reduce the oil recovery *** the other hand,this adsorption property of clay materials can be used to prevent surface and underground water pollution and reduce soil *** this experimental study,the effect of surfactant concentration,electrolyte type(NaCl and MgCl_(2)),and the solution salinity on fluid adsorption into the interlayer space of different clay types(bentonite and kaolinite)was *** analysis was conducted on two relevant clay samples,and immersion and Washburn tests were performed on the desired samples with the Sigma 700 ***,according to the clay type,the most optimal conditions were introduced for the surfactant solution used in the two areas of EOR and environmental processes related to reducing soil *** the EOR processes,the optimal condition for the lowest adsorption amount is C(with 1 CMC concentration and salinity of 100,000 ppm for NaCl salt).This fluid works better in kaolinite *** the environmental field related to the reduction of soil pollution,if the pollutants we are looking for are R and S(with alkyl benzene sulfonic acid as the dominant agent),bentonite has a better performance than kaolinite in terms of adsorption and subsequently pollution *** the polluting fluid contains MgCl_(2) ions in the exact salinity values,the adsorption amount and soil pollution control will be higher for both adsorbent clays than if our fluid has NaCl *** study's findings have a wide range of applications in surfactant flooding designs,surfactant adsorption optimization,and can be generalized to other detergent types.

关键词： EOR Adsorption Clay Bentonite Kaolinite Soil pollution Surfactant Immersion test Washburn test Salinity

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Biomimetic microchannel network with functional endothelium formed by sacrificial electrospun fibers inside 3D gelatin methacryloyl(GelMA)hydrogel models

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Journal of Zhejiang University-Science A(Applied Physics & engineering) 2024年第1期25卷 79-96页

作者： Haoyu SUN Haiyang MA Li WANG Yang LIU Tian HOU Wenjie TANG Qing YU Meiwen AN Meiling WEN Institute of Biomedical engineering College of Biomedical EngineeringTaiyuan University of TechnologyTaiyuan030024China

Three-dimensional(3D)hydrogel models play a crucial role in tissue engineering for promoting tissue regeneration.A biomimetic microchannel network system in the 3D hydrogel model is necessary for optimal cellular *** report describes the preparation of a biomimetic hydrogel scaffold with an internal microchannel network,using electrospinning techniques and the sacrificial template method for 3D cell *** and cavities were created within the gelatin methacryloyl(GelMA)hydrogel by sacrificing polyvinyl alcohol(PVA)electrospun fibers(>10µm),resulting in the creation of microvessel-like *** characterizations,swelling properties,and biodegradation analysis were conducted to investigate the feasibility of a biomimetic microchannel network hydrogel scaffold for 3D cell culture *** to pure GelMA hydrogel,the hydrogel with microchannels promoted cell proliferation,adhesion,and endothelial tube ***,the results confirmed that the biomimetic microchannel network scaffold had a major impact on the distribution and arrangement of human umbilical vein endothelial cells(HUVECs)and can enable the formation of artificial microvasculature by the culture of HUVECs and cell media perfusion.

关键词： Biomimetic scaffold Photocrosslinking Microchannel network Tissue engineering Artificial microvascular

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Two-dimensional C_(2)N-based single-atom catalyst with complex microenvironment for enhanced electrochemical nitrogen reduction:A descriptor-based design

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Journal of Energy Chemistry 2024年第10期97卷 110-119,I0003页

作者： Enduo Dai Wei An Ruixian Guo Xugen Shi Yunyi Li Yibo Wang Mingming Liu college of Chemistry and Chemical engineering.Shanghai University of engineering Science Shanghai 201620China

The catalytic descriptor with operational feasibility is highly desired towards rational design of high-performance catalyst especially the electrode/electrolyte solution interface working under mild ***,we demonstrate that the descriptorΩparameterized by readily accessible intrinsic properties of metal center and coordination is highly operational and efficient in rational design of single-atom catalyst(SAC)for driving electrochemical nitrogen reduction(NRR).Using twodimensional metal(M)-B_(x)P_(y)S_(z)N_m@C_(2)N as prototype SAC models,we reveal that^(*)N_(2)+(H~++e~-)→^(*)N_(2)H acts predominantly as the potential-limiting step(PLS)of NRR on M-B_(2)P_(2)S_(2)@C_(2)N and M-B_(1)P_(1)S_(1)N_(3)@C_(2)N regardless of the distinction in coordination *** the 28 screened M active sites,withΩvalues close to the optimal 4,M-B_(2)P_(2)S_(2)@C_(2)N(M=V(Ω=3.53),Mo(Ω=5.12),and W(Ω=3.92))and M-B_(1)P_(1)S_(1)N_(3)@C_(2)N(M=V(Ω=3.00),Mo(Ω=4.34),and W(Ω=3.32))yield the lowered limiting potential(U_(L))as-0.45,-0.54.-0.36,-0.58,-0.25,and-0.24 V,respectively,thus making them the promising NRR *** importantly,these SACs are located around the top of volcano-shape plot of U_(L) versusΩ,re-validatingΩas an effective descriptor for accurately predicting the high-activity NRR SACs even with complex *** study unravels the relationship between active-site structure and NRR performance via the descriptorΩ,which can be applied to other important sustainable electrocatalytic reactions involving activation of small molecules viaσ-donation andπ^(*)-backdonation mechanism.

关键词： Electrocatalysis N_(2) reduction Single-atom catalyst Descriptor DFT

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High-efficiency and flexible photonic microwave harmonic down-converter based on self-oscillation optical frequency combs

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Chinese Optics Letters 2024年第6期22卷 196-204页

作者： Xin Zhang Tao Pu Huatao Zhu Yunshan Zhang Gengze Wu Jin Li Jilin Zheng college of Information and Communications National University of Defense TechnologyWuhan 430010China college of Communications engineering Army Engineering University of PLANanjing 210007China college of Electronic and Optical engineering&college of Flexible Electronics(Future Technology) Nanjing University of Posts and TelecommunicationsNanjing 210023China

Photonic microwave harmonic down-converters (PMHDCs) based on self-oscillation optical frequency combs (OFCs) are interesting because of their broad bandwidth compared with plain optoelectronic oscillators. In this paper, a high-efficiency and flexible PMHDC is proposed and demonstrated. The properties of the OFC, such as the carrier-to-noise ratio (CNR),bandwidth and free spectral range (FSR), and the influence of optical injection, are investigated. The broadband OFC provides a frequency tunable and high-quality local oscillation (LO), which guarantees flexible down-conversion for the radio frequency (RF) signal. The sideband selective amplification (SSA) effect not only improves the conversion efficiency but also promotes single-sideband modulation. The conversion range can reach 100 GHz. The 12–40 GHz RF signal can be downconverted to intermediate frequency (IF) signals with a high conversion efficiency of 14.9 dB. The fixed 40-GHz RF signal is flexibly down-converted to an IF signal with the frequency from 55.4 to 2129.4 MHz. The phase noise of an IF signal at a frequency offset of 10 kHz is the same as that of the input RF signal. The PMHDC shows great performance and will find applications in radio-over-fiber (RoF) networks, electronic warfare receivers, avionics, and wireless communication systems.

关键词： frequency down-conversion optical frequency comb optical injection optoelectronic oscillation

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