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Molecular Dynamics-Based Simulation of Polyethylene Pipe Degradation in High Temperature and High Pressure Conditions

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Fluid Dynamics & Materials Processing 2024年第9期20卷 2139-2161页

作者： guowei Feng Qing li Yang Wang Nan lin Sixi zha Hang dong Ping Chen Minjun Zheng School of Mechanical Engineering Xinjiang UniversityUrumqi830046China Xinjiang Yian Special Inspection Engineering Company limited Urumqi830063China Xinjiang Uygur Autonomous Region Inspection Institute of Special Equipment Urumqi830000China Pressure Pipe Department China Special Equipment Inspection and Research InstituteBeijing100013China Tarim Oilfield Branch Company Korla841000China Yimai Cai Oil and gas Management Area Tarim Oilfield Branch OfficeKorla841000China

High-density polyethylene(HDPE)pipes have gradually become the first choice for gas networks because of their excellent *** the use of pipes increases,there will unavoidably be a significant amount of waste generated when the pipes cease their operation life,which,if improperly handled,might result in major environmental contamination *** this study,the thermal degradation of polyethylene materials is simulated for different pressures(10,50,100,and 150 MPa)and temperatures(2300,2500,2700,and 2900 K)in the framework of Reactive Force Field(ReaxFF)molecular dynamics *** main gas products,density,energy,and the mean square displacement with temperature and pressure are also *** findings indicate that raising the temperature leads to an increase in the production of gas products,while changing the pressure has an impact on the direction in which the products are generated;the faster the temperature drops,the less dense the air;both temperature and pressure increase impact the system’s energy conversion or distribution mechanism,changing the system’s potential energy as well as its total energy;the rate at which molecules diffuse increases with temperature,and decreases with *** results of this investigation provide a theoretical basis for the development of the pyrolytic treatment of polyethylene waste materials.

关键词： ReaxFF MD high-density polyethylene degradation temperature pressure

Chiral transfer amidst one-dimensional linear polymers and twodimensional network covalent organic frameworks:Striking a fine balance between helicity and crystallinity

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Nano Research 2024年第6期17卷 5726-5734页

作者： Xinlin zha Mengjuan Zuo guilin Xu Zhong Yan Haining You Yi Xiong Ying liu Yingying li liyan Yang Ke liu Mufang li Tao zhao dong Wang College of Chemistry and Chemical Engineering Donghua UniversityShanghai 201620China Key Laboratory of Textile Fiber and Products Ministry of EducationWuhan Textile UniversityWuhan 430200China

The current landscape of chiral covalent organic frameworks(COFs)predominantly centered on constructing asymmetric molecular-scale chirality,often introducing an inherent contradiction to the COF symmetry and limiting ***,we overcome these challenges by achieving chiral transfer between one-dimensional(1D)imine linear polymers(LPs)and two-dimensional(2D)networkβ-ketoenamine COFs composed of achiral *** successfully synthesize several 1D imine LPs with mesoscopic helical chirality,comprising achiral C2-symmetric terephthalaldehyde and diamine linkers in a chiral supramolecular transcription *** the irreversible tautomerism mechanism within the linker replacement approach,terephthalaldehyde(TPA)units in these helical 1D LPs are substituted with C3-symmetric 1,3,5-triformylphloroglucinol(TP),yielding the corresponding 2D networkβ-ketoenamine *** and helicity of the resultantβ-ketoenamine COFs intimately hinge on reaction conditions,including the aldehyde stoichiometry of Tp and TPA,as well as the quantity and concentration of the catalyst *** optimized conditions,the nucleation and growth were precisely governed,achieving a harmonious equilibrium of crystallinity and helicity within the generated 2D networkβ-ketoenamine COFs,even with covalent bond rupture,recombination,and topological transition(from[C2+C2]to[C3+C2]).Impressively,the ground state chirality inherent to helical 1D LPs seamlessly transfers to helical 2D networkβ-ketoenamine *** study not only offers new perspectives on the development of chiral functional COFs,but also provides fresh insights into the precise control of COFs'microscopic morphology.

关键词： chiral covalent organic frameworks chiral transfer dimensional transformation helicity

The interventional effect of Polygonatum cyrtonema Hua polysaccharide on atherosclerosis in mice of different sexes

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Food Science and Human Wellness 2024年第1期13卷 370-380页

作者： Anjun guo Xueying li lihua Pan Qiangming li Jianping Luo Xueqiang zha Engineering Research Centre of Bioprocess of Ministry of Education Hefei University of TechnologyHefei 230009China School of Food and Biological Engineering Hefei University of TechnologyHefei 230009China Key Laboratory of Metabolism and Regulation for Major Disease of Anhui Higher Education Institutes Hefei University of TechnologyHefei 230009China

In the present study,we investigated the intervention effects of a purified Polygonatum cyrtonema polysaccharide(PCP)on high-fat diet(HFD)-induced atherosclerosis in male and female LDLr-/-*** showed that HFD caused severe dyslipidemia,atherosclerotic lesions,oxidative damages and inflammation in male and female mice,and these effects seemed to be more pronounced in males than in ***,the above variations could be dose-dependently reversed by PCP treatment,and the intervention effects on males were greater than those on *** factor kappa-B(NF-κB),mitogen-activated protein kinase(MAPKs)and protein kinase B(Akt)are 3 pivotal signaling pathways mediating the development of ***,PCP was also found to significantly decrease the phosphorylation of p65,p38,extracellular-regulated kinase 1/2(ERK1/2)and Akt,and increase the protein expression of inhibitor of NF-κB(IκB)in the aortas of male and female mice induced by *** together,these findings indicated that PCP could be effective for the prevention of atherosclerosis,and the intervention effect of PCP on male mice was more obvious than that of female mice.

关键词： Polygonatum cyrtonema polysaccharide Anti-atherosclerosis Sex

geometric Error Identification of gantry-Type CNC Machine Tool Based on Multi-Station Synchronization Laser Tracers

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Chinese Journal of Mechanical Engineering 2024年第2期37卷 150-162页

作者： Jun zha Huijie zha.g School of Mechanical Engineering Xi’an Jiaotong UniversityXi’an 710049China Xi’an Jiaotong University Suzhou Academy Suzhou 215123China

Laser tracers are a three-dimensional coordinate measurement system that are widely used in industrial *** propose a geometric error identification method based on multi-station synchronization laser tracers to enable the rapid and high-precision measurement of geometric errors for gantry-type computer numerical control(CNC)machine *** method also improves on the existing measurement efficiency issues in the single-base station measurement method and multi-base station time-sharing measurement *** consider a three-axis gantry-type CNC machine tool,and the geometric error mathematical model is derived and established based on the combination of screw theory and a topological analysis of the machine kinematic *** four-station laser tracers position and measurement points are realized based on the multi-point positioning principle.A self-calibration algorithm is proposed for the coordinate calibration process of a laser tracer using the Levenberg-Marquardt nonlinear least squares method,and the geometric error is solved using Taylor’s first-order linearization *** experimental results show that the geometric error calculated based on this modeling method is comparable to the results from the Etalon laser *** a volume of 800 mm×1000 mm×350 mm,the maximum differences of the linear,angular,and spatial position errors were 2.0μm,2.7μrad,and 12.0μm,respectively,which verifies the accuracy of the proposed *** research proposes a modeling method for the precise measurement of errors in machine tools,and the applied nature of this study also makes it relevant both to researchers and those in the industrial sector.

关键词： Multi-point positioning Multi-station synchronization CNC machine tool geometric error Error separation

Reinforcement Learning Navigation for Robots Based on Hippocampus Episode Cognition

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Journal of Bionic Engineering 2024年第1期21卷 288-302页

作者： Jinsheng Yuan Wei guo Zhiyuan Hou Fusheng zha Mantian li Pengfei Wang lining Sun State Key Laboratory of Robotics and System Harbin Institute of Technology(HIT)Harbin 150001China Shenzhen Academy of Aerospace Technology Shenzhen 518057China School of Mechanical and Electrical Engineering Lanzhou University of TechnologyLanzhou 730050China

Artificial intelligence is currently achieving impressive success in all ***,autonomous navigation remains a major challenge for *** learning is used for target navigation to simulate the interaction between the brain and the environment at the behavioral level,but the Artificial Neural Network trained by reinforcement learning cannot match the autonomous mobility of humans and *** hippocampus–striatum circuits are considered as key circuits for target navigation planning and *** paper aims to construct a bionic navigation model of reinforcement learning corresponding to the nervous system to improve the autonomous navigation performance of the *** ventral striatum is considered to be the behavioral evaluation region,and the hippocampal–striatum circuit constitutes the position–reward *** this paper,a set of episode cognition and reinforcement learning system simulating the mechanism of hippocampus and ventral striatum is constructed,which is used to provide target guidance for the robot to perform autonomous *** with traditional methods,this system reflects the high efficiency of learning and better Environmental *** research is an exploration of the intersection and fusion of artificial intelligence and neuroscience,which is conducive to the development of artificial intelligence and the understanding of the nervous system.

关键词： Episode cognition Reinforcement learning Hippocampus Robot navigation

Synergistically enhanced dielectric, insulating and thermally conductive performances of sandwich PMMA based dielectric films

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Progress in Natural Science:Materials International 2024年第3期34卷 591-597页

作者： dongmei zha.g Yufan li Yuchao li Zhonggui Sun Hanxue Zhu Lujia Yang Yanhu zhan Yankai li Shi Wang Jun-Wei zha School of Mathematical Sciences Liaocheng University School of Materials Science and Engineering Liaocheng University State Key Laboratory of Organic Electronics and Information Displays & Institute of Advanced Materials (IAM) Nanjing University of Posts & Telecommunications School of Chemistry and Biological Engineering University of Science and Technology Beijing

A tri-layered(B-g-B) dielectric films were simply prepared by alternatively spin-coating boron nitride/polymethylmethacrylate(BN/PMMA, B) and graphene nanosheets(gNS/PMMA, g) compound solutions. The structure, morphology, thermal conductivity, and particularly the dielectric and relaxation behaviors were systematically studied. Results showed that a good exfoliation and dispersion of BN and gNS can be simply achieved through intensive mechanical compounding with PMMA in the internal mixer. The dielectric constant and breakdown strength of the obtained 1-3-1(B-g-B) sandwich composite film reached 4.3(@1 kHz) and 458.6kV/mm, being 119 % and 113 % higher than that of pure PMMA, respectively. Furthermore, the overall thermal conductivity of sandwich 1-3-1 composite increased by 112 % due to the addition of thermally conductive BN and gNS. The sandwich design strategy provided an effective way of achieving good permittivity, high insulation, and improved thermal conductivity simultaneously, showing potential applications in the miniaturization and integration of electronic devices.

关键词： Breakdown strength Composites Dielectric constant Sandwich structure Thermal conductivity

Transient Stability Analysis of Converter-based Islanded Microgrids Based on Iterative Equal Area Criterion Considering Reactive Power Loop Dynamics and Varying Damping

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Journal of Modern Power Systems and Clean Energy 2024年第4期12卷 1170-1182页

作者： Xilin li Jingyi zha.g Zhen Tian Xiaoming zha Wei Wang Meng Huang Chong Shao Hubei Key Laboratory of Power Equipment&System Security for Integrated Energy School of Electrical Engineering and AutomationWuhan UniversityWuhanChina NARI Technology Co. Ltd.NanjingChina State grid gansu Electric Power Company LanzhouChina

With the rapid increase in the installed capacity of renewable energy in modern power systems,the stable operation of power systems with considerable power electronic equipment requires further *** converter-based islanded mi-crogrid(CIM)systems equipped with grid-following(gFL)and grid-forming(gFM)voltage-source converters(VSCs),it is chal-lenging to maintain stability due to the mutual coupling effects between different VSCs and the loss of voltage and frequency sup-port from the power *** previous studies,quantitative transient stability analysis was primarily used to assess the active power loop of ***,frequency and voltage dy-namics are found to be strongly coupled,which strongly affects the estimation result of stability *** addition,the vary-ing damping terms have not been fully *** bridge these gaps,this paper investigates the transient stability of CIM consid-ering reactive power loop dynamics and varying ***,an accuracy-enhanced nonlinear model of the CIM is derived based on the effects of reactive power loop and post-disturbance frequency jump *** these effects will elimi-nates the risk of *** reactive power loop dynamics make the model coefficients be no longer constant and thus vary with the power *** evaluate quantitatively the effects of re-active power loop and varying damping on the transient stability of CIM,an iterative criterion based on the equal area criterion theory is *** addition,the effects of parameters on the stable boundary of power system are analyzed,and the dynamic interaction mechanisms are *** and experiment results verify the merits of the proposed method.

关键词： Transient stability converter iterative criterion reactive power loop post-disturbance frequency jump

Circularly polarized light emission and detection by chiral inorganic semiconductors

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Frontiers of Optoelectronics 2024年第2期17卷 43-49页

作者： zha li Wancai li Dehui li Wei Tang Huageng liang Huaibing Song Chao Chen liang gao Jiang Tang Wuhan National Laboratory for Optoelectronics Huazhong University of Science and TechnologyWuhan 430074China School of Optical and Electronic Information Huazhong University of Science and TechnologyWuhan 430074China International Health Care Center National Center for Global Health and MedicineTokyo 162‑8655Japan Hepato‑Biliary‑Pancreatic Surgery Division Department of SurgeryThe University of Tokyo HospitalTokyo 113‑8655Japan Department of Urology Union HospitalTongji Medical CollegeHuazhong University of Science and TechnologyWuhan 430074China Faculty of Materials Science and Chemistry China University of GeosciencesWuhan 430074China

Chiral inorganic semiconductors with high dissymmetric factor are highly desirable,but it is generally difficult to induce chiral structure in inorganic semiconductors because of their structure rigidity and *** this study,we introduced chiral ZnO film as hard template to transfer chirality to CsPbBr_(3) film and PbS quantum dots(QDs)for circularly polarized light(CPL)emission and detection,*** prepared CsPbBr_(3)/ZnO thin film exhibited CPL emission at 520 nm and the PbS QDs/ZnO film realized CPL detection at 780 nm,featuring high dissymmetric factor up to around *** electron transition based mechanism is responsible for chirality transfer.

关键词： High dissymmetric factor Circularly polarized light emission Semiconductor Hard template,Chirality

Risk factors for postpartum posttraumatic stress disorder after emergency admission

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World Journal of Emergency Medicine 2024年第2期15卷 121-125页

作者： Fengxia Du Jun zha Yan li lichao Fang Shuyu Xia Youjia Yu Department of Obstetrics Suzhou Xiangcheng People’s HospitalSuzhou 215131China Department of Anesthesiology the Second Affiliated Hospital of Wannan Medical CollegeWuhu 241000China Department of Anesthesiology Suzhou Xiangcheng People’s HospitalSuzhou 215131China Department of Emergency and Intensive Care Unit Suzhou Xiangcheng People’s HospitalSuzhou 215131China

BACKgROUND:Postpartum posttraumatic stress disorder(PTSD)can occur in women who give birth after emergency *** identification of risk factors for this condition is crucial for developing effective preventive *** retrospective study aimed to explore the incidence and risk factors for postpartum PTSD in women who give birth after emergency ***:Medical records of women who gave birth after emergency admission were collected between March 2021 and April *** patients’general conditions and perinatal clinical indicators were *** puerperae were divided into PTSD group and control group based on symptom occurrence at six weeks *** logistic regression analysis was performed to identify risk ***:A total of 276 puerperae were included,with a PTSD incidence of 20.3% at six weeks *** logistic regression analysis identified emergency cesarean section(odds ratio[OR]=2.102;95%confidence interval[CI]:1.114-3.966,P=0.022),admission to the emergency department after midnight(12:00 AM)(OR=2.245;95%CI:1.170-4.305,Pgainst postpartum ***:Emergency cesarean section,admission to the emergency department after midnight,and cervical dilation were identified as independent risk factors for postpartum PTSD,while analgesic pump use was a protective *** findings provide insights for developing more effective preventive measures for women who give birth after emergency admission.

关键词： Risk factors Posttraumatic stress disorder Emergency Delivery