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Effect of an antioxidant on the life cycle of wood flour/polypropylene composites

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Journal of Forestry Research 2020年第4期31卷 1435-1443页

作者： Haigang wang Jingfa Zhang Haitao Fu weihong wang Qingwen wang Key Laboratory of Bio-Based Material Science and Technology(Ministry of Education) Northeast Forestry UniversityHarbin 150040People’s Republic of China College of Materials and Energy South China Agricultural UniversityGuangzhou 510642People’s Republic of China

This study assessed the life cycle of biocomposites with antioxidants by repeated *** effects of antioxidants on the life cycle of wood flour/polypropylene(PP)composites were determined by analyzing their mechanical and thermal *** composites were repeatedly processed for seven times with pelletizing and *** antioxidant,pentaerythritoltetrakys 3-(3,5-ditert-butyl-4-hydroxyphenyl)propionate,was *** mechanical strength of the biocomposites decreased after *** transformed infrared analysis showed that thermo-oxidative aging occurred during *** thermal performance of the resulting composites decreased because of *** flour/PP has a long lifetime and antioxidants can slow the thermo-oxidative and mechanical degradation during reprocessing.

关键词： Wood-plastic composites Polypropylene Reprocessing Antioxidant

Non-isothermal crystallization kinetics of wood-flour/polypropylene composites in the presence of b-nucleating agent

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Journal of Forestry Research 2016年第4期27卷 949-958页

作者： Lang Huang Haigang wang weihong wang Qingwen wang Yongming Song Key Laboratory of Bio-Based Material Science and Technology (Ministry of Education) Northeast Forestry University

The influence of aryl amide compounds（TMB）as b-nucleating agents, on the non-isothermal crystallization of a wood-flour/polypropylene composite（WF/PP）prepared by compression molding was investigated by wide-angle X-ray diffraction and differential scanning calorimetry. TMB was proved to be an effective b-crystalline nucleating agent for WF/PP. The DSC data showed that the crystallization peak temperature（Tp） increased and the half-time（t1/2） decreased with the addition of *** theoretical models were used to analyze the nonisothermal crystallization process. The modified Avrami method and Mo method successfully explained the nonisothermal crystallization behavior of PP and its composites. Their activation energies for non-isothermal crystallization were determined basing on the Kissinger method.

关键词： isothermal kinetics crystalline polypropylene calorimetry nucleation flour molding crystallinity amide

Identifiability Analysis of Load Model Parameters by Estimating Confidential Intervals

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CSEE Journal of Power and Energy Systems 2023年第5期9卷 1666-1675页

作者： Xinran Zhang Chao Lu Ying wang Qiantu Ruan Hongbo Ye weihong wang the School of Automation Science and Electrical Engineering Beihang UniversityBeijing 100191China. the State Key Laboratory of Control and Simulation of Power System and Generation Equipment Tsinghua UniversityBeijing 100084China School of Technology Beijing Forestry UniversityBeijing 100083China the State Grid Shanghai Electric Power Company Shanghai 200122China

The identification of load model parameters from practical measurement data has become an essential method to build load models for power system simulation,analysis and *** practical situations,the accuracy of the load model parameters identification results is impacted by data quality and measurement accuracy,which leads to the problem of *** this paper,an identifiability analysis methodology of load model parameters,by estimating the confidential intervals(CIs)of the parameters,is *** load model structure and the combined optimization and regression method to identify the parameters are first ***,the definition and analysis method of identifiability are *** CIs of the parameters are estimated through the profile likelihood method,based on which a practical identifiability index(PII)is defined to quantitatively evaluate ***,the effectiveness of the proposed analysis approach is validated by the case study results in a practical provincial power *** results show that the impact of various disturbance magnitudes,measurement errors and data length can all be reflected by the proposed ***,the proposed PII can provide guidance in data length selection in practical load model identification situations.

关键词： Confidential interval Load modeling parameter estimation practical identifiability

Improvement in the Performance of the Polylactic Acid Composites by Using Deep Eutectic Solvent Treated Pulp Fiber

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Journal of Renewable Materials 2021年第11期9卷 1897-1911页

作者： Lei Tan Liangxian Liu Chaodong Liu weihong wang Key Laboratory of Bio-Based Material Science and Technology(Ministry of Education) Material Science and Engineering CollegeNortheast Forestry UniversityHarbin150040China

As the most favorable alternative to petroleum-based polymers,polylactic acid(PLA)which is the most promising degradable polymer has attracted increasing ***,the addition of cellulose to improve its strength often results in a reduction in its *** this work,microscale cellulose is first prepared from pulp fibers by using a deep eutectic solvent,and then is used as the reinforcement of PLA.A microcrystalline cellulose(MCC)/PLA sheet with uniform texture is obtained by the solution mixing,melt blending,hot-pressing and cold-pressing *** effects of MCC on the crystallization,thermal stability and mechanical properties of the PLA matrix were *** the addition of 1%cellulose fiber,the tensile strength of MCC/PLA composite sheet increased by 27%,and the elongation at break did not shown an evident *** strength enhancement mechanism was elucidated using scanning electron microscopy,differential scanning calorimetry,and dynamic thermomechanical *** energy dissipation during the deformation process and the compatibility of AMCC and rougher surface of MCC play important role in the strength ***,UV spectroscopy showed that the composite material absorbed some ultraviolet *** results show that the combined use of a deep eutectic solvent and solution mixing is an effective approach for improving the strength of PLA while maintaining its toughness.

关键词： Polylactic acid microcrystalline cellulose deep eutectic solvent mechanical properties

Biocomposites of Polylactic Acid Reinforced by DL-Lactic Acid-Grafted Microfibrillated Cellulose

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Journal of Renewable Materials 2022年第11期10卷 2961-2972页

作者： Chaodong Liu Yutong Yang Boyu Cui weihong wang Key Laboratory of Bio-Based Material Science and Technology(Ministry of Education) Material Science and Engineering CollegeNortheast Forestry UniversityHarbin150040China

Microfibrillated cellulose(MFC)is often added to polylactic acid(PLA)matrixes as a reinforcing filler to obtain fully-biodegradable composites with improved mechanical ***,the incompatibility between MFC and the PLA matrix limits the mechanical performance of MFC-reinforced PLA *** this paper,DL-lactic acid-grafted-MFC(MFC-g-DL)was used to improve the compatibility with *** composites were prepared by melt extrusion and hot-cold *** tensile strength of the PLA/MFC-g-DL composite increased by 22.1%compared with that of PLA after adding 1%*** electron microscopy(SEM),differential scanning calorimetry(DSC),and dynamic thermomechanical analysis(DMA)were used to explore the enhancement *** energy dissipation in the MFC network and the improved compatibility between PLA and MFC-g-DL played important roles in the *** SEM results showed that there was a closer combination between PLA and *** DSC results showed that the addition of cellulose changed the glass transition temperature,melting temperature,and crystallization temperature of *** TG results showed that the initial and maximum decomposition temperature were lower than those of *** ultraviolet spectra showed that the composite had good transparency at a low concentration of MFC-g-DL.

关键词： Polylactic acid microfibrillated cellulose tensile properties transparency

Development of a Novel Extrusion Process for Preparing Rice Straw/LLDPE Composites

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Journal of Renewable Materials 2023年第3期11卷 1123-1135页

作者： Huicheng Xu Hao Xie Weidong Shan weihong wang Key Laboratory of Bio-Based Material Science and Technology(Ministry of Education) Material Science and Engineering CollegeNortheast Forestry UniversityHarbin150040China

Straw utilization is a key issue related to agricultural production and air pollution *** this study,a novel extrusion process was proposed to improve the physical and mechanical properties of the straw-reinforced linear low-density polyethylene(LLDPE)*** of crushing the straw and mixing it with plastic matrix,the new method mixes straw with plastic matrix in its original *** intact long rice straws were parallelly spread on the LLDPE film and then rolled up together into a prefabricated *** rolls experienced three extrusion processes as follows:(1)twin-screw melting,cooling and crushing,single-screw extruding;(2)twin-screw melting and single-screw extruding;(3)directly single-screw *** testing results showed that the straw/LLDPE composite(with a ratio of 6:4)prepared by Method(2)exhibited optimized *** by scanning electron microscopy indicated that the damage to rice straw fibers was relatively minor,the orientation of long fibers was good,and the binding of fibers with the LLDPE matrix was excellent in this *** results of dynamic mechanical testing(DMA),differential scanning calorimetry(DSC)and thermogravimetric(TG)analysis demonstrated that composites prepared by the new process exhibited significantly improved thermal stability and energy storage modulus,compared with those prepared by conventional processes(e.g.,extruded straw particles/LLDPE composite).The new proposed method yielded significantly enhanced mechanical properties while reducing dust pollution.

关键词： Long rice straw linear low density polyethylene film extrusion mechanical property

Radiation injury and gut microbiota-based treatment

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Protein & Cell 2024年第2期15卷 83-97页

作者： weihong wang Bota Cui Yongzhan Nie Lijuan Sun Faming Zhang Department of Microbiota Medicine and Medical Center for Digestive Diseases The Second Affiliated Hospital of Nanjing Medical UniversityNanjing210011China Department of Microbiotherapy Sir Run Run HospitalNanjing Medical UniversityNanjing 211166China State Key Laboratory of Holistic Integrative Management of Gastrointestinal Cancers and National Clinical Research Center for Digestive Diseases Xijing Hospital of Digestive DiseasesFourth Military Medical UniversityXi'an 710032China National Clinical Research Center for Digestive Diseases Xi'an 710032China Key Laboratory of Resource Biology and Biotechnology in Western China Ministry of EducationSchool of MedicineNorthwest UniversityXi'an 710069China

The exposure to either medical sources or accidental radiation can cause varying degrees of radiation injury(RI).RI is a common disease involving multiple human body parts and organs,yet effective treatments are currently *** evidence suggests gut microbiota are closely associated with the development and prevention of various *** article summarizes 10 common types of RI and their possible *** also highlights the changes and potential microbiota-based treatments for RI,including probiotics,metabolites,and microbiota ***,a 5P-Framework is proposed to provide a comprehensive strategy for managing RI.

关键词： microbiome ionizing radiation radiation-induced injury short-chain fatty acids fecal microbiota transplant washed microbiota transplantation war nuclear microbiota medicine

Cyber-Physical Resilience Enhancement for Power Transmission Systems with Energy Storage Systems

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CSEE Journal of Power and Energy Systems 2024年第2期10卷 844-855页

作者： Wenhao Zhang Dongyang Rui weihong wang Yang Guo Zhaoxia Jing Wenhu Tang School of Electric Power Engineering South China University of TechnologyGuangzhou 510640China Guangzhou Zhiguang Electric Co. Ltd and Zhiguang Research Institute(Guangzhou)Co.LtdGuangzhou 510765China

In a power system, when extreme events occur, such as ice storm, large scale blackouts may be unavoidable. Such small probability but high risk events have huge impact on power systems. Most resilience research in power systems only considers faults on the physical side, which would lead to overly idealistic results. This paper proposes a two-stage cyber-physical resilience enhancement method considering energy storage (ES) systems. The first stage calculates optimal planning of ES systems, and the second stage assesses resilience and enhancement of ES systems during the disaster. In the proposed model, cyber faults indirectly damage the system by disabling monitoring and control function of control center. As a result, when detection and response process of physical faults are blocked by cyber failures, serious load shedding occurs. Such a cyber-physical coupling mechanism of fault, response, restoration process is demonstrated in the modified IEEE Reliable Test System-79 (RTS-79). Simulation results show compared with the physical-only system, the cyber-physical system has a more accurate but degraded resilient performance. Besides, ES systems setting at proper place effectively enhance resilience of the cyber-physical transmission system with less load Shedding.

关键词： Cyber-physical faults energy storage systems resilience enhancement transmission systems

Properties of paper mill sludge–wood fiber–HDPE composites after exposure to xenon-arc weathering

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Journal of Forestry Research 2015年第2期26卷 509-515页

作者： Xiaohui Yang Xianquan Zhang weihong wang Haibing Huang Shujuan Sui Key Lab of Bio-Based Material Science & Technology of Education Ministry Northeast Forestry University Heilongjiang Wood Science Research Institute

We used paper mill sludge（PMS） to substitute for part of the wood fibers（WF） used to reinforce high density polyethylene（HDPE）.The resulting composites were subjected to xenon-arc *** composite filled with limited PMS（under 10 %） had mechanical properties and aging resistance similar to those without *** composites containing more PMS faded and cracked more readily than those without *** on the carbonyl index,crystallinity,and wood index,PMS appeared to accelerate the degradation of composites during *** PMS to WF–HDPE composites reduced the weathering resistance,and this reduction was not significant if the PMS content did not exceed 20 % of the wood ***,PMS could be used as a reinforcement in wood-plastic composites at levels less than20 % of the wood fiber content.

关键词： Wood fiber Paper mill sludge HDPE Composites Xenon-arc weathering