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Poly(lactic acid)/Poly(butylene adipate-co-terephthalate)films with simultaneous high oxygen barrier and fast degradation properties

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Green Energy & Environment 2025年第1期10卷 1-10页

作者： Mengjing Yang Yuxi Mao Penghui Zhang Jie Li Zeming Tong zhenguo liu Yanhui Chen Institute of Flexible Electronics Northwestern Polytechnical UniversityXi'an710072China Key Laboratory of Flexible Electronics of Zhejiang Province Ningbo Institute of Northwestern Polytechnical University218 Qingyi RoadNingbo315103China School of Chemistry and Chemical Engineering Shaanxi Key Laboratory of Macromolecular Science and TechnologyKey Laboratory of Special Functional and Smart Polymer Materials of Ministry of Industry and Information TechnologyNorthwestern Polytechnical UniversityXi'an 710072China

Although poly(lactic acid)(PLA)is a good environmentally-friendly bio-degradable polymer which is used to substitute traditional petrochemical-based polymer packaging films,the barrier properties of PLA films are still insufficient for high-barrier packaging *** this study,oxygen scavenger hydroxyl-terminated polybutadiene(HTPB)and cobalt salt catalyst were incorporated into the PLA/poly(butylene adipate-co-terephthalate)(PLA/PBAT),followed by melting extrusion and three-layer co-extrusion blown film process to prepare the composite *** oxygen permeability coefficient of the composite film combined with 6 wt%oxygen scavenger and 0.4 wt%catalyst was decreased significantly from 377.00 cc·mil·m^(-2)·day^(-1)·0.1 MPa^(-1) to 0.98 cc·mil·m^(-2)·day^(-1)·0.1 MPa^(-1),showing a remarkable enhancement of 384.69 times compared with the PLA/PBAT composite ***,the degradation behavior of the composite film was also accelerated,exhibiting a mass loss of nearly 60%of the original mass after seven days of degradation in an alkaline environment,whereas PLA/PBAT composite film only showed a mass loss of 32%.This work has successfully prepared PLA/PBAT composite films with simultaneously improved oxygen barrier property and degradation behavior,which has great potential for high-demanding green chemistry packaging industries,including food,agricultural,and military packaging.

关键词： Barrier property Oxygen scavenging Blow molding Eco-packaging Degradable composite film

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Tracking Control of Uncertain High-Order Nonlinear Systems with Odd Rational Powers and the Dead-Zone Input:A Direct Fuzzy Adaptive Control Method

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Journal of Systems Science & Complexity 2022年第5期35卷 1685-1699页

作者： liu zhenguo SHI Yuyuan WU Yuqiang School of Automation and Software Engineering Shanxi UniversityTaiyuan 030006China Institute of Automation Qufu Normal UniversityQufu 273165China

This work studies the tracking issue of uncertain nonlinear *** existence of odd rational powers,multiple unknown parameters and the dead-zone input add many difficulties for control *** procedures of the control design,by introducing an appropriate Lyapunov function,utilizing recursive control method and the inequality technique,some appropriate intermediate auxiliary control laws are designed under the hypothesis that nonlinear terms in the system are *** those nonlinear terms are unknown,by employing the powerful approximation ability of fuzzy systems,the intermediate auxiliary control laws are approximated recursively and used to construct the virtual ***,a new fuzzy adaptive tracking controller is constructed to ensure a small tracking error and the boundedness of all *** this paper,the overparameterization problem is significantly avoided since only two adaptive laws are *** and practical examples are used to verify the raised theory.

关键词： Dead-zone input direct fuzzy adaptive control uncertain systems

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Nonlinear Flow Properties of Newtonian Fluids through Rough Crossed Fractures

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Computer Modeling in Engineering & Sciences 2023年第8期136卷 1427-1440页

作者： zhenguo liu Shuchen Li Richeng liu Changzhou Zheng Geotechnical and Structural Engineering Research Center Shandong UniversityJinan250061China Sinohydro Foundation Engineering Co. Ltd.Tianjin301700China State Key Laboratory for Geomechanics andDeepUnderground Engineering China University of Mining and TechnologyXuzhou221116China

The nonlinear flow properties of Newtonian fluids through crossed fractures are estimated by considering the influences of length,aperture,and surface roughness of fractures.A total of 252 computational runs are performed by creating 36 computational domains,in which the Navier-Stokes equations are *** results show that the nonlinear relationship between flow rate and hydraulic gradient follows Forchheimer’s law–based *** the hydraulic gradient is small(i.e.,10^(−6)),the streamlines are parallel to the fracture walls,indicating a linear streamline *** the hydraulic gradient is large(i.e.,10^(0)),the streamlines are disturbed by a certain number of eddies,indicating a nonlinear streamline *** patterns of eddy distributions depend on the length,aperture,and surface roughness of *** the increment of hydraulic gradient from 10^(−6) to 10^(0),the ratio of flow rate to hydraulic gradient holds constants and then decreases slightly and finally decreases *** fluid flow experiences a linear flow regime,a weakly nonlinear regime,and a strongly nonlinear regime,*** critical hydraulic gradient ranges from 3.27×10^(−5) to 5.82×10^(−2) when fracture length=20–100mmandmechanical aperture=1–*** joint roughness coefficient plays a negligible role in the variations in critical hydraulic gradient compared with fracture length and/or mechanical *** critical hydraulic gradient decreases with increasing mechanical aperture,following power-law *** parameters in the functions are associated with fracture length.

关键词： Crossed fractures surface roughness aperture nonlinear flow critical hydraulic gradient

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Investigation on the Thermal Conductivity of 3-Dimensional and 4-Directional Braided Composites

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Chinese Journal of Aeronautics 2007年第4期20卷 327-331页

作者： liu zhenguo Zhang Haiguo Lu Zixing Li Diansen Institute of Solid Mechanics Beijing University of Aeronautics and Astronautics Beijing 100083 China

It is vital to choose a factual and reasonable micro-structural model of braided composites for improving the calculating precision of thermal property of 3-D braided composites by finite element method （FEM）. On the basis of new microstructure model of braided composites proposed recently, the model of FEM calculation for thermal conductivity of 3-dimennsional and 4-directional braided composites is set up in this paper. The curves of coefficient of effective thermal conductivity versus fiber volume ratio and interior braiding angle are obtained. Furthermore, comparing the results of FEM with the available experimental data, the reasonability and veracity of calculation are confirmed at the same time.

关键词： 3-dimennsional and 4-directional braided composites thermal conductivity FEM

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A step towards the application of molecular plasmonic-like excitations of PAH derivatives in organic electrochromics

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Chinese Chemical Letters 2023年第2期34卷 174-178页

作者： Yanan Zhu Xing Xing zhenguo liu Hong Meng School of Advanced Materials Peking University Shenzhen Graduate SchoolShenzhen 518055China Shenzhen Research Institute of Northwestern Polytechnical University Shenzhen 518057China Institute of Flexible Electronics Northwestern Polytechnical UniversityXi'an 710072China

Polycyclic aromatic hydrocarbons(PAHs), are regarded as molecular fragments of graphene and are facilely available through chemical synthesis. Recently, it is found collective charge density oscillations with strong induced electromagnetic field display in PAH derivatives. This phenomenon, analogue to plasmonic excitation in metal, called molecular plasmonics, arise the significant interest of physicists. Instead of discussing its rich physics, this work aims at the application of molecular plasmon-like excitations in electrochromics and optoelectronics. We found that the energy and the intensity of plasmonic-like oscillation could be largely tuned by increasing the conjugation size along both the longitude/transverse axis in PAHs. Besides, the dimeric PAH demonstrates the possibility that molecular plasmonics could be designed using PAHs as building blocks for integration into larger molecular systems. Moreover, this work straightforwardly extends the molecular plasmonic-like property from C–H composed PAHs to much more versatile planar conjugation systems with heteroatoms, achieving transferring between p-type and n-type organic semiconductors. Therefore, with the natural abundance, low cost, easily chemical synthesis of PAH derivatives, we believe this work paves the way for the application of molecular plasmonic-like properties in optoelectronics.

关键词： Molecular plasmonic Organic electrochromics Polycyclic aromatic hydrocarbon p/n-type organic semiconductor

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Experimental Study on Effects of Fuel Injection on Scramjet Combustor Performance

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Chinese Journal of Aeronautics 2007年第6期20卷 488-494页

作者： Wu Xianyu Li Xiaoshan Ding Meng liu Weidong Wang zhenguo College of Aerospace and Material Engineering National University of Defense Technology ChangSha 410073 China

In order to investigate the effects of fuel injection distribution on the scrarnjet combustor performance, there are conducted three sets of test on a hydrocarbon fueled direct-connect scramjet test facility. The results of Test A, whose fuel injection is carried out with injectors located on the top-wall and the bottom-wall, show that the fuel injection with an appropriate close-front and centralized distribution would be of much help to optimize combustor performances. The results of Test B, whose fuel injection is performed at the optimal injection locations found in Test A, with a given equivalence ratio and different injection proportions for each injector, show that this injection mode is of little benefit to improve combustor performances. The results of Test C with a circumferential fuel injection distribution displaies the possibility of ameliorating combustor performance. By analyzing the effects of injection location parameters on combustor performances on the base of the data of Test C, it is clear that the injector location has strong coupled influences on combustor performances. In addition, an irmer-force synthesis specific impulse is used to reduce the errors caused by the disturbance of fuel supply and working state of air heater while assessing combustor performances.

关键词： scramjet combustor fuel injection direct-cormect test

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GLP-1 receptor agonists and myocardial metabolism in atrial fibrillation

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Journal of Pharmaceutical Analysis 2024年第5期14卷 653-665页

作者： Jiani Zhong Hang Chen Qiming liu Shenghua Zhou zhenguo liu Yichao Xiao Department of Cardiovascular Medicine Second Xiangya HospitalCentral South UniversityChangsha410011China Xiangya School of Medicine Central South UniversityChangsha410008China Center for Precision Medicine and Division of Cardiovascular Medicine Department of MedicineSchool of MedicineUniversity of MissouriColumbiaMO65211USA

Atrial fibrillation(AF)is the most common cardiac *** medical conditions,including hypertension,diabetes,obesity,sleep apnea,and heart failure(HF),increase the risk for *** have unique metabolic characteristics to maintain adenosine triphosphate *** changes occur in myocardial metabolism in ***-like peptide-1 receptor agonists(GLP-1RAs)have been used to control blood glucose fluctuations and weight in the treatment of type 2 diabetes mellitus(T2DM)and ***-1RAs have also been shown to reduce oxidative stress,inflammation,autonomic nervous system modulation,and mitochondrial *** article reviews the changes in metabolic characteristics in cardiomyocytes in *** the clinical trial outcomes are unsatisfactory,the findings demonstrate that GLP-1 RAs can improve myocardial metabolism in the presence of various risk factors,lowering the incidence of AF.

关键词： Atrial fibrillation Glucagon-like peptide-1 receptor agonists Metabolism

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Monitoring on subsidence due to repeated excavation with DInSAR technology

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International Journal of Mining Science and Technology 2013年第2期23卷 185-190页

作者： liu zhenguo Bian Zhengfu Lü Fuxiang Dong Baoquan School of Environmental Science & Spatial Informatics China University of Mining & Technology Jiangsu Key Laboratory of Resources and Environmental Information Engineering Xishan Coal Electricity Group Co. Ltd.

DInSAR technology was used to monitor subsidence caused by underground coal mining activities in mountainous area, with multi source SAR data, including 8 EnviSAT C-band and 4 ALOS L-band, and 4 programmed TerraSAR-X dataset. The results revealed that 2-pass DInSAR technique sometimes failed to retrieve the mining-caused subsidence due to spatial and/or temporal de-correlation. We also noticed that there existed residual topographic phase after the compensation with SRTM DEM, which could almost overwhelm the subsidence information when the perpendicular baseline was relatively large. Based on the mining materials, analysis was made on the shape of subsidence area. For the well geocoded results from TerraSAR-X, confirmed by GPS surveying results of corner reflectors, we tried to extract the advance distance of influence besides the subsidence area. Due to the big deformation gradient over stopingfaces, the X-band SAR data could not capture the maximum value subsidence revealed by GPS survey in our preliminary results, the same as C-band EnviSAT data. This will turn to be our research subject in the next few months.

关键词： DInSAR Repeated excavation Corner reflectors Subsidence TerraSAR-X

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Inhibition of Sirtuin 2 exerts neuroprotection in aging rats with increased neonatal iron intake

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Neural Regeneration Research 2014年第21期9卷 1917-1922页

作者： Xijin Wang Meihua Wang liu Yang Jie Bai Zhiqiang Yan Yuhong Zhang zhenguo liu Department of Neurology Xinhua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine Shanghai Laboratory Animal Center Chinese Academy of Sciences Department of Neurology Shanghai Tenth People’s HospitalTongji University

Impaired iron homeostasis may cause damage to dopaminergic neurons and is critically involved in the pathogenesis of Parkinson’s disease. At present, very little is understood about the effect of neonatal iron intake on behavior in aging animals. Therefore, we hypothesized that increased neonatal iron intake would result in signiifcant behavior abnormalities and striatal dopamine depletion during aging, and Sirtuin 2 contributes to the age-related neurotoxicity. In the present study, we observed that neonatal iron intake （120 μg/g per day） during postnatal days 10–17 resulted in significant behavior abnormalities and striatal dopamine depletion in aging rats. Furthermore, after AK-7 （a selective Sirtuin 2 inhibitor） was injected into the substantia nigra at postnatal 540 days and 570 days （5 μg/side per day）, striatal dopamine depletion was signiifcant-ly diminished and behavior abnormality was improved in aging rats with neonatal iron intake. Experimental ifndings suggest that increased neonatal iron intake may result in Parkinson’s dis-ease-like neurochemical and behavioral deifcits with aging, and inhibition of Sirtuin 2 expression may be a neuroprotective measure in Parkinson’s disease.

关键词： nerve regeneration Parkinson’s disease iron homeostasis disruption aging dopamine corpus striatum neurotoxicity Sirtuin AK-7 NSFC grants neural regeneration

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Effects of resource availability on the trade-off between seed and vegetative reproduction

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Journal of Plant Ecology 2010年第4期3卷 251-258页

作者： Lanke Fu Shichang Wang zhenguo liu Ivan Nijs Keping Ma Zhenqing Li State Key Laboratory of Vegetation and Environmental Change Institute of BotanyChinese Academy of SciencesBeijing 100093China Graduate University of Chinese of Academy Sciences Beijing 100049China School of Life Sciences Shanghai UniversityShanghai 200444China Research Group of Plant and Vegetation Ecology Department of BiologyUniversity of AntwerpCampus Drie EikenUniversiteitsplein 1B-2610 WilrijkBelgium

Aims To explore whether the trade-off between seed and vegetative reproductive modes is flexible in environments with different amounts of available resources to maintain optimal *** A transition matrix model was established to determine the optimal trade-off between seed and vegetative reproduction in resources–variable *** Findings The model predicts that plants allocate more resources to seed reproduction when available resources are *** increasing resources,more vegetative propagules are ***,if resources keep increasing to a harmful level,plants would switch to seeds again.

关键词： sexual reproduction vegetative reproduction trade-off resource

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