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Dynamics modeling and pressure control of composites tape winding system based on LQSMC

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Chinese Journal of Aeronautics 2020年第2期33卷 740-748页

作者： qi HONG Yaoyao shi Danni LU The Key Laboratory of Contemporary Design and Integrated Manufacturing Technology Ministry of Education Northwestern Polytechnical UniversityXi’an 710072China

Pressure fluctuations during the composite fiber winding process seriously affect the produces compactness strength,fatigue resistance,stress uniformity,and resin *** accuracy of pressure control systems is affected by nonlinear disturbances,such as friction,parameter perturbation,and measurement noise.A robust control algorithm based on linear quadratic optimal control and sliding mode control(LQSMC)is proposed to overcome these *** method is based on the system state space expression and linear quadratic optimal *** state space model of the system is improved by using a Kalman filter and control input for state estimation,and a new sliding surface equation is *** ameliorated control algorithm exhibits good performance and can effectively suppress sliding mode control(SMC)*** and experimental results show that LQSMC offers high control precision,much stronger antiinterference,and robustness,which can effectively improve the positioning and tracking accuracy of a pressure control system compared with linear quadratic optimal control(LQC).The winding pressure control precision is improved by 45%to 50%.The results show that the porosity of composite fiber tape winding products decreased thanks to our method.

关键词： Composites tape winding Dynamics modeling Kalman filter LQSMC Pressure control

Hydrogen storage thermodynamics and kinetics of as-cast Ce-Mg-Ni-based alloy

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Journal of Iron and Steel Research International 2024年第3期31卷 752-766页

作者： Yan qi Xin Zhang Jun Li Dong-liang Zhao shi-hai Guo yang-huan Zhang Department of Functional Material Research Central Iron and Steel Research InstituteBeijing 100081China China Rare Earth New Material(Weishan)Co..Ltd. Jining 277600ShandongChina Collaborative Innovation Center of Integrated Exploitation of Bayan Obo Multi-Metal Resources Inner Mongolia University of Science and TechnologyBaotou 014010Inner MongoliaChina

The reaction kinetics of alloys based on magnesium are known to be greatly improved by the partial substitution of Mg with rare earths and transition metals,particularly *** enhanced superficial hydrogen dissociation rate,the weakened Mg-H bond and the lower activation energy following element replacement are thought to be related to the better *** experimental alloys Ce5Mg_(95-x)Ni_(x)(x=5,10,15)were smelted by the vacuum induction *** phase transformation and structural evolution of experimental alloys before and after reaction with hydrogen were char-acterized by X-ray diffraction,scanning electron microscopy and transmission electron *** cast specimens contain CeMg_(12),Mg and Mg_(2)Ni phases,and the increase in Ni content results in an obvious growth of Mg_(2)Ni *** isothermal and non-isothermal hydrogenation and dehydrogenation kinetics of the experimental specimens were investi-gated using the Sievert apparatus,differential scanning calorimetry and thermal gravimetric *** activation energy may be calculated using the Arrhenius and Kissinger *** experimental alloys have been shown to have good activation properties,with a reversible hydriding and dehydriding capacities of around 5.0 wt.%in the first *** initial dehydrogenation temperature of MgH_(2) decreases from 557.5 to 537.7 K with changing Ni content from 5 to 15 at.%.The dehydrogenation activation energy also reduces from 77.09 to 62.96 kJ/mol,which explains the improved hydrogen storage performance caused by Ni *** can be shown that the impact of Ni on the decomposition enthalpy of MgH_(2) is quite modest,with the absolute enthalpy(ΔHr)only decreasing from 78.48 to 76.15 kJ/mol.

关键词： Mg-based alloy Ni content Hydrogen storage kinetics Thermodynamic property Activation energy

Evolution of Conformation and Dynamics of Solvents in Hydration Shell along the Urea-induced Unfolding of Ubiquitin

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Chinese Journal of Polymer Science 2019年第7期37卷 708-718页

作者： Ke-Cheng yang Feng-Chao Cui Ce shi Wen-Duo Chen Yun-qi Li Key Laboratory of Synthetic Rubber Changchun Institute of Applied ChemistryChinese Academy of SciencesChangchun 130022China Smart City Research Institute Zhengzhou UniversityZhengzhou 450001China

A clear diagram for the unfolding of protein induced by denaturant is a classical but still unsolved challenge. To explore the unfolded conformations of ubiquitin under different urea concentrations, we performed hybrid Monte Carlo-molecular dynamics simulations (MC-MD) guided by small angle X-ray scattering (SAXS) structural information. Conformational ensembles sampled by the hybrid MC-MD algorithm exhibited typical 3D structures at different urea concentrations. These typical structures suggested that ubiquitin was subjected to a sequential unfolding, where the native contacts between adjacent β-sheets at first were disrupted together with the exposure of hydrophobic core, followed by the conversion of remaining β-strands and helices into random coils. Ubiquitin in 8 mol·L?1 urea is almost a random coil. With the disruption of native structure, urea molecules are enriched at protein hydrated layer to stabilize newly exposed residues. Compared with water, urea molecules prefer to form hydrogen bonds with the backbone of ubiquitin, thus occupying nodes of the hydrogen bonding network that construct the secondary structure of proteins. Meanwhile, we also found that the slow dynamics of urea molecules was almost unchanged while the dynamics of water was accelerated in the hydration shell when more residues were unfolded and exposed. The former was also responsible for the stabilization of unfolded structures.

关键词： Ubiquitin Unfolding process Hydration behavior and dynamics Water and urea

Unified modeling of high temperature deformations of a Ni-based polycrystalline wrought superalloy under tension-compression, cyclic, creep and creep-fatigue loadings

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Science China(Technological Sciences) 2015年第2期58卷 248-257页

作者： HUANG Jia shi Duo qi yang Xiao Guang YU Hui Chen DONG Cheng Li School of Energy and Power Engineering Beihang University Beijing Institute of Aeronautical Materials

The complex deformation behaviors under tension-compression, cyclic, creep and creep-fatigue loadings of a nickel-base polycrystalline wrought superalloy at 650℃ and 700℃ were experimentally investigated. To uniformly simulate the complex deformation behaviors, the modified viscoplastic constitutive model combined with both the Kachanov damage evolution equation and the Ohno-Wang modification was formulated on the basis of the Chaboche theory. The simulated results on ten-sion-compression behavior, cyclic viscoplastic and creep deformations showed comprehensive predicting ability. With the obtained material parameters, the deformations in creep-fatigue interaction under three dwell types were simulated and the capability of the modified model was further verified with good accuracy.

关键词： superalloy constitutive relation fatigue creep creep-fatigue interaction

Constitutive modeling of a directionally solidified nickel-based superalloy DZ125 subjected to thermal mechanical creep fatigue loadings

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Rare Metals 2019年第10期38卷 922-936页

作者： Xiao-An Hu Xiao-Guang yang Duo-qi shi Hui-Chen Yu Ting-Ting Ren School of Energy and Power Engineering Beihang UniversityBeijing 100191China Science and Technology on Advanced High Temperature Structural Materials Laboratory Beijing Institute of Aeronautical MaterialsBeijing 100095China Air Force Armament Department China Aviation MuseumBeijing 102211China

A transversely isotropic continuum elasto-viscoplasticity model,which was developed from Chaboche’s unified constitutive model,was formulated to capture the thermal mechanical creep fatigue deformation behavior of a directionally solidified nickel-based superalloy.A fourthorder tensor was introduced to model material *** order to model the tertiary creep behavior,the Kachanov damage evolution equation was coupled into the stress *** on the test results of uniaxial tensile,fatigue,and creep loadings at isothermal temperature conditions,the material parameters are *** mechanical fatigue(TMF) and creep-fatigue interaction test results were used to verify the robustness of the ***,strain-temperature-dependent stress-strain responses under TMF loadings were analyzed using the present *** strain-controlled conditions,both of the stress ranges and mean stresses are strongly influenced by the strain-temperature phases,a key parameter for TMF tests.

关键词： Constitutive Thermal mechanical fatigue Creep Viscoplastic Superalloy

Effects and evaluation of biogas slurry/water integrated irrigation technology on the growth,yield and quality of tomatoes

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International Journal of Agricultural and Biological Engineering 2022年第5期15卷 123-131页

作者： Jian Zheng Xingyun qi Shaohong yang Cong shi Zhengjiang Feng College of Energy and Power Engineering Lanzhou University of TechnologyLanzhou 730050China Key Laboratory of Complementary Energy System of Biomass and Solar Energy Gansu ProvinceLanzhou 730050China Western China Energy&Environment Research Center Lanzhou University of TechnologyLanzhou 730050China

Reasonable techniques and methods in biogas slurry application are significant for the promotion of biogas slurry and the improvement of crop quality in agricultural *** investigate the impacts of different biogas slurry application techniques on the water use efficiency,growth,yield,and quality of tomatoes,three irrigation techniques,and two application methods were considered in this *** three irrigation techniques are alternate partial root-zone irrigation(APRI),fixed partial root-zone irrigation(FPRI),and two sides root-zone irrigation(TSRI).Two application methods refer to applying the biogas slurry with hole irrigation and surface *** addition,principal component analysis(PCA)and technique for order preference by similarity to ideal solution(TOPSIS)methods were adopted to evaluate the comprehensive quality and comprehensive indicators of tomatoes among different *** are three hole irrigation treatments,T1(APRI),T2(TSRI),T3(FPRI),and three surface irrigation treatments,T4(APRI),T5(TSRI),and T6(FPRI)were set in two-season pot *** results show that the plant height,dry matter accumulation,fruit yield,and water use efficiency present a similar descending trend for APRI,TSRI,and FPRI under the same methane irrigation method,yet show that the hole irrigation treatment was higher than the surface irrigation treatment for the same irrigation *** indicate that the coupling of APRI technique and hole irrigation is more conducive to the increase of plant production and water use ***,T1 treatment can significantly improve the soluble sugar,sugar-acid ratio,VC content,soluble protein,soluble solid content,and firmness of tomato fruits,which are better for the taste,storage,and transportation of tomato *** titratable acid content in tomato fruit is the highest in T2 treatment,followed by T5 treatment,indicating that TSRI technique may result in an accumulation of titratable acid and is not

关键词： biogas slurry irrigation technique coupling quality evaluation comprehensive index evaluation

Conceptual Model for Automatic Early Warning Information System of Infectious Diseases Based on Internet Reporting Surveillance System

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Biomedical and Environmental Sciences 2007年第3期20卷 208-211页

作者： JIA-qi MA LI-PING WANG XIAO-PENG qi XIAO-MING shi GONG-HUAN yang National Center for Public Health Surveillance and Information Services Chinese Center for Disease Control and Prevention Beijing 100050 China

Objective To establish a conceptual model of automatic early warning of infectious diseases based on internet reporting surveillance system, with a view to realizing an automated warning system on a dally basis and timely identifying potential outbreaks of infectious diseases. Methods The statistic conceptual model was established using historic surveillance data with movable percentile method. Results Based on the infectious disease surveillance information platform, the conceptual model for early warning was established. The parameter, threshold, and revised sensitivity and specificity of early warning value were changed to realize dynamic alert of infectious diseases on a dally basis. Conclusion The instructive conceptual model of dynamic alert can be used as a validating tool in institutions of infectious disease surveillance in different districts.

关键词： Infectious disease Automated warning Information system

Joule–Thomson expansion of higher dimensional nonlinearly AdS black hole with power Maxwell invariant source

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Communications in Theoretical Physics 2021年第6期73卷 110-118页

作者： Zhong-Wen Feng Xia Zhou Guansheng He shi-qi Zhou Shu-Zheng yang Physics and Space Science College China West Normal UniversityNanchong637009China School of Mathematics and Physics University of South ChinaHengyang421001China

In this paper,the Joule–Thomson expansion of the higher dimensional nonlinearly anti-de Sitter(Ad S)black hole with power Maxwell invariant source is *** results show the Joule–Thomson coefficient has a zero point and a divergent point,which coincide with the inversion temperature Tiand the zero point of the Hawking temperature,*** inversion temperature increases monotonously with inversion *** the high-pressure region,the inversion temperature decreases with the dimensionality D and the nonlinearity parameter s,whereas it increases with the charge ***,Tifor the low-pressure region increase with D and s,while it decreases with *** ratioηBHbetween the minimum inversion temperature and the critical temperature does not depend on Q,it recovers the higher dimensional Reissner–N?rdstrom Ad S black hole case when s=***,for s>1,it becomes smaller and smaller as D increases and approaches a constant when D→∞.Finally,we found that an increase of mass M and s,or reducing the charge Q and D can enhance the isenthalpic curve,and the effect of s on the isenthalpic curve is much greater than other parameters.

关键词： Joule–Thomson expansion Maxwell invariant source higher dimensional nonlinearly AdS black hole

L^(2) Extension and Effectiveness of L^(p) Strong Openness Property

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Acta Mathematica Sinica,English Series 2023年第5期39卷 814-826页

作者： shi Jie BAO qi An GUAN School of Mathematical Sciences Peking UniversityBeijing 100871P.R.China

In this note,we present an L^(2) extension approach to the effectiveness result of L^(P) strong openness property of multiplier ideal sheaves.

关键词： Optimal L^(2)extension multiplier ideal sheaf L^(P)strong openness property