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Improving aircraft nose wheel steering stability based on control continuation method

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Science China Technological Sciences 2025年第3期68卷 262-281页

作者： Qiaozhi YIN Dexu KONG Jiawei WANG Hong NIE Xiaohui WEI National key laboratory of Helicopter Aeromechanics key laboratory of Fundamental Science for National Defense-Advanced Design Technology of Flight vehicle AVIC Nanjing Engineering Institute of Aircraft Systems State key laboratory of Mechanics and control for Aerospace Structures

Aircraft steering instability during the taxiing process sometimes occurs resulting from the unstable bifurcation phenomena of the nonlinear steering dynamic system, which may lead to severe accidents. In this study, the control parameter design of an aircraft nose wheel steering control system based on the control continuation method is proposed to reduce the number of unstable bifurcation points and enlarge the system stable region area in a certain parameter domain. Thus, the aircraft turning performance can be improved greatly. First, a nonlinear aircraft rollout dynamic model is constructed, and the aircraft ground steering bifurcation characteristics are obtained under the open-loop steering control system. Then, the bifurcation performances under three closed-loop nose wheel steering controllers based on the feedback control method are compared, and the control parameter of the quadratic nonlinear controller with a better bifurcation control effect is selected as a second bifurcation parameter to analyze the directional system stability via two-parameter bifurcation analysis. Further, the influence of a crosswind on the aircraft ground steering bifurcation performance is studied for various control parameter values. Then, the control effects of a traditional proportional-integral-derivative(PID) nose wheel steering control law and the designed feedback controller are compared and analyzed. Finally, a semi-physical experiment of the aircraft nose wheel steering system is carried out, and different control parameter values are selected for test verification, which can further verify the control effect of the designed nonlinear feedback controller. The results indicate that the feedback control method is unable to vary the system bifurcation types, but appropriate control parameter design can effectively shrink the system instability region and even eliminate the unstable Hopf bifurcation points under some specific working conditions, improving the aircraft grou

关键词： aircraft taxiing dynamics and stability nose wheel steering control system control continuation steering bifurcation characteristics quadratic feedback control

Recombinant chitinase-3-like protein 1 alleviates learning and memory impairments via M2 microglia polarization in postoperative cognitive dysfunction mice

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Neural Regeneration Research 2025年第9期20卷 2727-2736页

作者： Yujia Liu Xue Han Yan Su Yiming Zhou Minhui Xu Jiyan Xu Zhengliang Ma Xiaoping Gu Tianjiao Xia Department of Anesthesiology Nanjing Drum Tower HospitalAffiliated Hospital of Medical SchoolNanjing UniversityNanjingJiangsu ProvinceChina Medical School Nanjing UniversityNanjingJiangsu ProvinceChina jiangsu key laboratory of Molecular Medicine Nanjing UniversityNanjingJiangsu ProvinceChina State key laboratory of Pharmaceutical Biotechnology Nanjing UniversityNanjingJiangsu ProvinceChina Department of Anesthesiology Zhongshan HospitalFudan UniversityShanghaiChina

Postoperative cognitive dysfunction is a seve re complication of the central nervous system that occurs after anesthesia and surgery,and has received attention for its high incidence and effect on the quality of life of *** date,there are no viable treatment options for postoperative cognitive *** identification of postoperative cognitive dysfunction hub genes could provide new research directions and therapeutic targets for future *** identify the signaling mechanisms contributing to postoperative cognitive dysfunction,we first conducted Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analyses of the Gene Expression Omnibus GSE95426 dataset,which consists of mRNAs and long non-coding RNAs differentially expressed in mouse hippocampus3 days after tibial *** dataset was enriched in genes associated with the biological process"regulation of immune cells,"of which Chill was identified as a hub ***,we investigated the contribution of chitinase-3-like protein 1 protein expression changes to postoperative cognitive dysfunction in the mouse model of tibial fractu re *** were intraperitoneally injected with vehicle or recombinant chitinase-3-like protein 124 hours post-surgery,and the injection groups were compared with untreated control mice for learning and memory capacities using the Y-maze and fear conditioning *** addition,protein expression levels of proinflammatory factors(interleukin-1βand inducible nitric oxide synthase),M2-type macrophage markers(CD206 and arginase-1),and cognition-related proteins(brain-derived neurotropic factor and phosphorylated NMDA receptor subunit NR2B)were measured in hippocampus by western *** with recombinant chitinase-3-like protein 1 prevented surgery-induced cognitive impairment,downregulated interleukin-1βand nducible nitric oxide synthase expression,and upregulated CD206,arginase-1,pNR2B,and brain-derived neurotropic factor expr

关键词： Chil1 hippocampus learning and memory M2 microglia neuroinflammation postoperative cognitive dysfunction(POCD) recombinant CHI3L1

Chemical characteristics and sources apportionment of volatile organic compounds in the primary urban area of Shijiazhuang,North China Plain

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Journal of Environmental Sciences 2025年第3期149卷 465-475页

作者： Xiao Zhang Junfeng Wang Jiangwei Zhao Junliang He Yali Lei Kai Meng RuiWei Xue Zhang Miaomiao Zhang Shuangying Ni Eleonora Aruffo College of geographical sciences and Environment Shijiazhuang UniversityShijiazhuang 050035China jiangsu key laboratory of Atmospheric Environment Monitoring and Pollution control Collaborative Innovation Center of Atmospheric Environment and Equipment TechnologySchool of Environmental Science and EngineeringNanjing University of Information Science and TechnologyNanjing 210044China Hebei Province Ecology Environmental Monitoring Center Shijiazhuang 050037China key Lab of Geographic Information Science of the Ministry of Education School of Geographic SciencesEast China Normal UniversityShanghai 200241China Hebei Provincial Institute of Meteorological Sciences Shijiazhuang 050021China key laboratory of Meteorology and Ecological Environment of Hebei Province Shijiazhuang 050021China Hebei Provincial Academy of Ecological Environmental Science Shijiazhuang 050037China Department of Advanced Technologies in Medicine&Dentistry University“G.d’Annunzio”of Chieti-PescaraChieti 66100Italy Center for Advanced Studies and Technology-CAST Chieti 66100Italy

VOCs(Volatile organic compounds)exert a vital role in ozone and secondary organic aerosol production,necessitating investigations into their concentration,chemical characteristics,and source apportionment for the effective implementation of measures aimed at preventing and controlling atmospheric *** to October 2020,onlinemonitoringwas conducted in the main urban area of Shijiazhuang to collect data on VOCs and analyze their concentrations and ***,the PMF(positive matrix factorization)method was utilized to identify the VOCs *** indicated that the TVOCs(total VOCs)concentration was(96.7±63.4μg/m^3),with alkanes exhibiting the highest concentration of(36.1±26.4μg/m^3),followed by OVOCs(16.4±14.4μg/m^3).The key active components were alkenes and aromatics,among which xylene,propylene,toluene,propionaldehyde,acetaldehyde,ethylene,and styrene played crucial roles as reactive *** sources derived from PMF analysis encompassed vehicle emissions,solvent and coating sources,combustion sources,industrial emissions sources,as well as plant sources,the contribution of which were 37.80%,27.93%,16.57%,15.24%,and 2.46%,***,reducing vehicular exhaust emissions and encouraging neighboring industries to adopt low-volatile organic solvents and coatings should be prioritized to mitigate VOCs levels.

关键词： Volatile organic compounds Pollution characteristics Ozone formation potential OH radical loss rate Source apportionment

Recent advances and perspectives towards emission inventories of mobile sources:Compilation approaches,data acquisition methods,and case studies

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Journal of Environmental Sciences 2023年第1期123卷 460-475页

作者： Han Jiang Hefeng Zhang Mingliang Fu Zhihui Huang Hong Ni Hang Yin Yan Ding State Environmental Protection key laboratory of vehicle emission control and Simulation Chinese Research Academy of Environmental SciencesBeijing 100012China vehicle emission control Center of Ministry of Ecology and Environment Chinese Research Academy of Environmental SciencesBeijing 100012China

In recent years,great efforts have been devoted to reducing emissions from mobile sources with the dramatic growth of motor vehicle and nonroad mobile source *** of a mobile source emission inventory is conducive to the analysis of pollution emission characteristics and the formulation of emission reduction *** study summarizes the latest compilation approaches and data acquisition methods for mobile source emission *** motor vehicles,a high-resolution emission inventory can be developed based on a bottom-up approach with a refined traffic flow model and real-world speed-coupled emission *** top-down approach has advantages when dealing with macroscale vehicle emission estimation without substantial traffic flow *** nonroad mobile sources,nonroad machinery,inland river ships,locomotives,and civil aviation aircraft,a top-down approach based on fuel consumption or power is *** ocean-going ships,a bottom-up approach based on automatic identification system(AIS)data is *** typical cases are studied,including emission reduction potential,a cost-benefit model,and marine shipping emission *** and suggestions are given on future research directions for emission inventories for mobile sources:building localized emission models and factor databases,improving the dynamic updating capability of emission inventories,establishing a database of emission factors of unconventional pollutants and greenhouse gas from mobile sources,and establishing an urban high temporalspatial resolution volatile organic compound(VOC)evaporation emission inventory.

关键词： emission inventory Mobile source emission factor emission control policy

Insight into the promotional mechanism of Cu modification towards wide-temperature NH3-SCR performance of NbCe catalyst

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Chinese Journal of Chemical Engineering 2022年第10期50卷 301-309页

作者： Dongqi An Yuyao Yang Weixin Zou Yandi Cai Qing Tong Jingfang Sun Lin Dong key laboratory of Mesoscopic Chemistry of MOE School of Chemistry and Chemical Engineering and Jiangsu Key Laboratory of Vehicle Emissions ControlNanjing UniversityNanjing 210093China Center for Nanochemistry College of Chemistry and Molecular EngineeringPeking UniversityBeijing 100871China jiangsu key laboratory of vehicle emissions control School of EnvironmentNanjing UniversityNanjing 210093China jiangsu key laboratory of vehicle emissions control Center of Modern AnalysisNanjing UniversityNanjing 210093China key laboratory of Mesoscopic Chemistry of MOE School of Chemistry and Chemical Engineering and Jiangsu Key Laboratory of Vehicle Emissions ControlSchool of EnvironmentCenter of Modern AnalysisNanjing UniversityNanjing 210093China

A simple strategy of Cu modification was proposed to broaden the operation temperature window for NbCe *** best catalyst Cu0.010/Nb1Ce3 presented over 90%NO conversion in a wide temperature range of 200-400℃and exhibited an excellent H_(2)O or/and SO_(2) resistance at 275℃.To understand the promotional mechanism of Cu modification,the correlation among the"activity-structure-property"were tried to establish *** species highly dispersed on NbCe catalyst to serve as the active *** strong interaction among Cu,Nb and Ce promoted the emergence of NbO4 and induced more Bronsted acid *** Cu modification obviously enhanced the redox behavior of the NbCe ***,EPR probed the Cu species exited in the form of monomeric and dimeric Cu^(2+),the isolated Cu^(2+)acted as catalytic active sites to promote the reaction:Cu^(2+)-NO_(3)^(-)+NO(g)→Cu^(2+)-NO_(2)^(-)+NO_(2)(g).Then the generated NO_(2) would accelerate the fast-SCR reaction process and thus facilitated the lowtemperature deNO_(x) ***,surface nitrates became unstable and easy to decompose after Cu modification,thus providing additional adsorption and activation sites for NH3,and ensuring the improvement of catalytic activity at high *** the NH3-SCR reaction followed by E-R reaction pathway efficaciously over Cu_(0.010)/Nb_(1)Ce_(3) catalyst,the excellent H_(2)O and SO_(2) resistance was as expected.

关键词： NH_(3)-SCR NbCe catalyst Cu modification NO_(2)promoting effect Fast-SCR Flue gas

Influence of MnO_2 modification methods on the catalytic performance of CuO/CeO_2 for NO reduction by CO

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Journal of Rare Earths 2014年第2期32卷 131-138页

作者：姚小江熊燕孙敬方高飞邓昱汤常金董林 key laboratory of Mesoscopic Chemistry of MOE School of Chemistry and Chemical EngineeringNanjing University jiangsu key laboratory of vehicle emissions control Center of Modern AnalysisNanjing University

In order to investigate the influence of MnO2 modification methods on the catalytic performance of CuO/CeO2 catalyst for NO reduction by CO, two series of catalysts （xCuyMn/Ce and xCu/yMn/Ce） were prepared by co-impregnation and step- wise-impregnation methods, and characterized by means of X-ray diffraction （XRD）, Raman spectra, H2-temperature programmed reduction （H2-TPR）, in situ diffuse reflectance infrared Fourier transform spectra （in situ DRIFTS） techniques. Furthermore, the cata- lytic performances of these catalysts were evaluated by NO＋CO model reaction. The obtained results indicated that：（1） The catalysts acquired by co-impregnation method exhibited stronger interaction owing to the more sufficient contact among each component of the catalysts compared with the catalysts obtained by stepwise-impregnation method, which was beneficial to the improvement of the reduction behavior; （2） The excellent reduction behavior was conducive to the formation of low valence state copper species （Cu＋/Cu0） and more oxygen vacancies （especially the surface synergetic oxygen vacancies （SSOV, Cu＋-n-Mn（4-x）-）） during the reaction process, which were beneficial to the adsorption of CO species and the dissociation of NO species, respectively, and further promoted the en- hancement of the catalytic performance. Finally, in order to further understand the difference between the catalytic performances of these catalysts prepared by co-impregnation and stepwise-impregnation methods, a possible reaction mechanism （schematic diagram） was tentatively proposed.

关键词： rare earths ceria copper oxide deNOx manganese oxide modification methods

Effectiveness of Precursor emission Reductions for the control of Summertime Ozone and PM2.5 in the Beijing–Tianjin–Hebei Region under Different Meteorological Conditions

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Advances in Atmospheric Sciences 2025年第4期42卷 653-669页

作者： Jing QIAN Hong LIAO jiangsu key laboratory of Atmospheric Environment Monitoring and Pollution control Jiangsu Collaborative Innovation Center of Atmospheric Environment and Equipment TechnologySchool of Environmental Science and EngineeringNanjing University of Information Science&TechnologyNanjing 210044JiangsuChina

We used observed concentrations of air pollutants,reanalyzed meteorological parameters,and results from the Goddard Earth Observing System Chemical Transport Model to examine the relationships between concentrations of maximum daily 8-h average ozone(MDA8 O_(3)),PM_(2.5)(particulate matter with diameter of 2.5μm or less),and PM_(2.5)components and 2-m temperature(T2)or relative humidity(RH),as well as the effectiveness of precursor emission reductions on the control of O_(3) and PM_(2.5) in Beijing–Tianjin–Hebei(BTH)under different summertime temperature and humidity *** observed(simulated)MDA8 O_(3) and PM_(2.5) concentrations increased as T2 went up,with linear trends of 4.8(3.2)ppb℃^(−1) and 1.9(1.5)μg m^(−3)℃^(−1),*** results showed that the decreases in MDA8 O_(3) from precursor emission reductions were more sensitive to T2 than to *** a larger proportion of volatile organic compound(VOC)emissions at higher T2 was more effective for the control of summertime O_(3) in *** the control of summertime PM_(2.5) in BTH,reducing nitrogen oxides(NOx)combined with a small proportion of VOCs was the best *** magnitude of reduction in PM_(2.5) from reducing precursor emissions was more sensitive to RH than to T2,with the best efficiency at high *** from this study are helpful for formulating effective policies to tackle O_(3) and PM_(2.5) pollution in BTH.

关键词： ozone PM_(2.5) emission reductions meteorological conditions

Evolution hydrothermal aging resistance mechanism study of zirconium and manganese doped CeO_(2)catalysts in soot catalytic combustion based on low Miller indices crystal surface effect

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Journal of Rare Earths 2024年第7期42卷 1272-1281,I0003页

作者： Zonglin Li Pan Wang Hong Ni Chengcheng Ao Lidong Zhang Hefeng Zhang Kai Li School of Automotive and Traffic Engineering Jiangsu UniversityZhenjiang212013China State Environmental Protection key laboratory of vehicle emission control and Simulation Chinese Research Academy of Environmental ScienceBeijing100012China National Synchrotron Radiation laboratory University of Science and Technology of ChinaHefei230026China

The thermogravimetric analysis(TGA)experiments were carried out to reveal the mechanism of Zr and Mn doping on catalytic activity of CeO_(2)catalyst both fresh and after hydrothermal aging,and the lattice morphology and valence changes were characterized by means of Brunauer-Emmett-Teller(BET)method,X-ray diffraction(XRD),X-ray photoelectron spectroscopy(XPS),and H_(2)-temperature programmed reduction(H_(2)-TPR).Density functional theory(DFT)and molecular thermodynamics calculations were applied to investigate the change in catalytic activity,crystal surface energy and crystal morphology caused by hydrothermal *** maximum reaction rate temperature of fresh Mn/CeO_(2)(389℃)is similar to that of CeO_(2)(371℃)and lower than that of Zr/CeO_(2)(447℃),but the catalytic performance of CeO_(2)decreases more severely after hydrothermal *** catalyst crystals show different degrees of crystal surface migration after hydrothermal aging,which leads to the reduction of Ce^(3+)/Ce^(4+) ratio and the active sites *** calculations indicate that the doping of Zr and Mn reduces the surface energy of the low Miller indices surface and increases the oxygen vacancy formation energy,leading to better thermal stability and lower catalytic *** Zr and Mn doping also changes the adsorption energy and Gibbs free energy of H_(2)O,which dominates the migration of(111)to(110)and(100)in the vapor *** crystal surface migration mechanism of CeO_(2)catalysts doped with Zr and Mn induced by H_(2)O molecules at high temperature obtained in this study can provide a valuable addition to the regeneration of CeO_(2)catalysts in the after-treatment systems of diesel engines.

关键词： Soot CeO_(2)-based catalyst CDPF Rare earth metal oxides DFT calculations

Improved control Strategy Based on Splitting-Capacitor for Grid-Connected Inverter 36

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Improved Control Strategy Based on Splitting-Capacitor for G...