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Multi-walled Carbon Nanotubes as a Ligand in Nickel ?-Diimine Based Ethylene polymerization

Chinese Journal of polymer Science 2015年第10期33卷 1389-1403页

作者： Sasan Talebnezhad Saeed Pourmahdian department of polymer engineering and color Technology Amirkabir University of Technology

Two novel heterogeneous nickel a-diimine based polymerization catalysts, containing MWCNT as the main ligand, were synthesized by novel in situ catalyst preparation technique. The in situ synthesis was performed by covalent attachment of the acenaphthenic ligand core to amine functionalized MWCNT ligand arms through diimine bonding and further nickel dibromide chelation. The prepared catalysts were fully characterized and their structures and supporting efficiencies were determined. Single or double introduction of the MWCNTs through their ends or sidewall（s） in the catalytic system, as a ligand, influenced the catalytic performance, microstructure and morphology of obtained polyethylenes. MWCNT sidewall bonding to para-aryl position of the tetramethylphenyl moiety performed as more electron-donating ligand than MWCNT ends linked to the imine bond and protected the catalytic system to retain its activity. This character resulted in the maintenance of the resulting polymer topology at elevated temperatures so that the catalytic activity and the obtained polymer melting points remained around 110 g PE·mmol^-1 Ni·h^-1 and 123 ℃ in all polymerization temperatures respectively. In polymerization trials, molecular weight fall against temperature was not as sharp as what had been observed in sequentially prepared catalysts insofar as the molecular weight of resultant polymer at 60 ℃ reached to 310000 g·mol^-1 which was close to the highest value had been reported at 30 ℃ for sequentially prepared catalysts. TEM observations showed the presence of the stopped-growth polymer chains due to geometrical constrains or ligand debonding for both catalytic systems.

关键词： a-Diiminonickel catalyst Ligand Multi-walled carbon nanotubes Ethylene polymerization In situ catalyst preparation.

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The Influence of Bridge Type on the Activity of Supported Metallocene Catalysts in Ethylene polymerization

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Chinese Journal of polymer Science 2014年第2期32卷 137-142页

作者： Alireza Talaei Faramarz Afshar Taromi Ahmad Arefazar Saeid Ahmadjo Omid Moini Jazani department of polymer engineering and color Technology Amirkabir University of Technology department of Catalyst Iran Polymer and Petrochemical Institute (IPPI) department of Chemical engineering College of Engineering University of Isfahan

Ethylene polymerization was carried out by immobilization of rac-ethylenebis（1-indenyl）zirconium dichloride （Et（Ind）2ZrCl2） and rac-dimethylsilylbis（1-indenyl）zirconium dichloride （Me2Si（Ind）2ZrCl2） preactivated with methylaluminoxane （MAO） on calcinated silica at different temperatures. polymerizations of ethylene were conducted at different temperatures to find the optimized polymerization temperature for maximum activity of the catalyst. The Me2Si bridge catalyst showed higher activity at the lower polymerization temperature compared to the Et bridge catalyst. The highest catalytic activities were obtained at temperatures about 50 ~C and 70 ~C for Me2Si（Ind）2ZrC1JMAO and Et（Ind）zZrCI2/MAO catalysts systems, respectively. Inductively coupled plasma-atomic emission spectroscopy results and polymerization activity results confirmed that the best temperature for calcinating silica was about 450 ℃ for both catalysts systems. The melting points of the produced polyethylene were about 130 ℃, which could be attributed to the linear structure of HDPE.

关键词： Slurry polymerization Olefin polymerization ansa-Metallocene Silica support.

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Bioinspired Passive Tactile Sensors Enabled by Reversible Polarization of Conjugated polymers

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Nano-Micro Letters 2025年第1期17卷 361-377页

作者： Feng He Sitong Chen Ruili Zhou Hanyu Diao Yangyang Han Xiaodong Wu School of Mechanical engineering Sichuan UniversityChengdu 610065People’s Republic of China School of Software engineering Chongqing University of Posts and TelecommunicationsChongqing 400065People’s Republic of China State Key Laboratory of polymer Materials engineering Sichuan UniversityChengdu 610065People’s Republic of China

Tactile perception plays a vital role for the human body and is also highly desired for smart prosthesis and advanced *** to active sensing devices,passive piezoelectric and triboelectric tactile sensors consume less power,but lack the capability to resolve static ***,we address this issue by utilizing the unique polarization chemistry of conjugated polymers for the first time and propose a new type of bioinspired,passive,and bio-friendly tactile sensors for resolving both static and dynamic ***,to emulate the polarization process of natural sensory cells,conjugated polymers(including poly(3,4-ethylenedioxythiophen e):poly(styrenesulfonate),polyaniline,or polypyrrole)are controllably polarized into two opposite states to create artificial potential *** controllable and reversible polarization process of the conjugated polymers is fully in situ ***,a micro-structured ionic electrolyte is employed to imitate the natural ion channels and to encode external touch stimulations into the variation in potential difference *** with the currently existing tactile sensing devices,the developed tactile sensors feature distinct characteristics including fully organic composition,high sensitivity(up to 773 mV N^(−1)),ultralow power consumption(nW),as well as superior *** demonstrations,both single point tactile perception(surface texture perception and material property perception)and two-dimensional tactile recognitions(shape or profile perception)with high accuracy are successfully realized using self-defined machine learning *** tactile sensing concept innovation based on the polarization chemistry of conjugated polymers opens up a new path to create robotic tactile sensors and prosthetic electronic skins.

关键词： Passive tactile sensors Reversible polarization of conjugated polymers Tactile perception Machine learning algorithm Object recognition

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Synthesis and Characterization of Novel Castor Oil-Based Polyol for Potential Applications in Coatings

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Journal of Renewable Materials 2019年第1期7卷 31-40页

作者： Azam Sardari Ali Asghar Sabbagh Alvani Seyed Reza Ghaffarian color&polymer Research Center(CPRC) Amirkabir University of TechnologyTehran158754413Iran department of polymer engineering and color Technology Amirkabir University of TechnologyTehran158754413Iran Advanced Materials Group Iranian Color Society(ICS)***TehranIran

In this study,three sorts of polyols were successfully synthesized from castor oil using a Dean-Stark quick,eco-friendly and high-efficiency *** this purpose,castor oil was epoxidized in the presence of two types of catalysts includingγ-alumina and formic acid,named as ECOAl and ECOF,*** castor oils were then characterized by use of hydrogen nuclear magnetic resonance(H-NMR)and oxirane oxygen content *** relative percentages of conversion double bond to oxirane were obtained 96% and 74% for ECOAl and ECOF,*** opening reaction of ECOAl was performed by two types of saponified castor oil as well as castor oil in a system equipped with Dean–Stark *** synthesized polyols were characterized by attenuated total reflectance-Fourier transform infrared spectroscopy(ATR-FTIR),gel permeation chromatography(GPC),differential scanning calorimetry(DSC),viscometer and OH number *** material obtained in this research is a candidate to be intended in synthesis of polyurethane for coating applications.

关键词： Castor oil dean-Stark polyol epoxidation

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Congruent Feature Selection Method to Improve the Efficacy of Machine Learning-Based Classification in Medical Image Processing

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Computer Modeling in engineering & Sciences 2025年第1期142卷 357-384页

作者： Mohd Anjum Naoufel Kraiem Hong Min Ashit Kumar Dutta Yousef Ibrahim Daradkeh department of Computer engineering Aligarh Muslim UniversityAligarh202002India College of Computer Science King Khalid UniversityAbha61413Saudi Arabia School of Computing Gachon UniversitySeongnam13120Republic of Korea department of Computer Science and Information Systems College of Applied SciencesAlMaarefa UniversityRiyadh13713Saudi Arabia department of Computer engineering and Information College of Engineering in Wadi AlddawasirPrince Sattam bin Abdulaziz UniversityAl-Kharj16273Saudi Arabia

Machine learning(ML)is increasingly applied for medical image processing with appropriate learning *** applications include analyzing images of various organs,such as the brain,lung,eye,etc.,to identify specific flaws/diseases for *** primary concern of ML applications is the precise selection of flexible image features for pattern detection and region *** of the extracted image features are irrelevant and lead to an increase in computation ***,this article uses an analytical learning paradigm to design a Congruent Feature Selection Method to select the most relevant image *** process trains the learning paradigm using similarity and correlation-based features over different textural intensities and pixel *** similarity between the pixels over the various distribution patterns with high indexes is recommended for disease ***,the correlation based on intensity and distribution is analyzed to improve the feature selection ***,the more congruent pixels are sorted in the descending order of the selection,which identifies better regions than the ***,the learning paradigm is trained using intensity and region-based similarity to maximize the chances of ***,the probability of feature selection,regardless of the textures and medical image patterns,is *** process enhances the performance of ML applications for different medical image *** proposed method improves the accuracy,precision,and training rate by 13.19%,10.69%,and 11.06%,respectively,compared to other models for the selected *** mean error and selection time is also reduced by 12.56%and 13.56%,respectively,compared to the same models and dataset.

关键词： Computer vision feature selection machine learning region detection texture analysis image classification medical images

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Advancements in Liver Tumor Detection:A Comprehensive Review of Various Deep Learning Models

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Computer Modeling in engineering & Sciences 2025年第1期142卷 91-122页

作者： Shanmugasundaram Hariharan D.Anandan Murugaperumal Krishnamoorthy Vinay Kukreja Nitin Goyal Shih-Yu Chen Deptartment of Artificial Intelligence and Data Science Vardhaman College of EngineeringHyderabad501218India Deptartment of CSE V.S.B College of EngineeringKarur639111India Deptartment of Electrical and Electronics engineering Vardhaman College of EngineeringHyderabad501218India Centre for Research Impact&Outcome Chitkara UniversityRajpura140401PunjabIndia department of Computer Science and engineering School of Engineering and TechnologyCentral University of HaryanaMahendergarh123031HaryanaIndia department of Computer Science and Information engineering National Yunlin University of Science and TechnologyYunlin64002Taiwan Intelligence Recognition Industry Service Research Center National Yunlin University of Science and TechnologyYunlin64002Taiwan

Liver cancer remains a leading cause of mortality worldwide,and precise diagnostic tools are essential for effective treatment *** Tumors(LTs)vary significantly in size,shape,and location,and can present with tissues of similar intensities,making automatically segmenting and classifying LTs from abdominal tomography images crucial and *** review examines recent advancements in Liver Segmentation(LS)and Tumor Segmentation(TS)algorithms,highlighting their strengths and limitations regarding precision,automation,and *** metrics are utilized to assess key detection algorithms and analytical methods,emphasizing their effectiveness and relevance in clinical *** review also addresses ongoing challenges in liver tumor segmentation and identification,such as managing high variability in patient data and ensuring robustness across different imaging *** suggests directions for future research,with insights into technological advancements that can enhance surgical planning and diagnostic accuracy by comparing popular *** paper contributes to a comprehensive understanding of current liver tumor detection techniques,provides a roadmap for future innovations,and improves diagnostic and therapeutic outcomes for liver cancer by integrating recent progress with remaining challenges.

关键词： Liver tumor detection liver tumor segmentation image processing liver tumor diagnosis feature extraction tumor classification deep learning machine learning

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Impact of Pollutant Concentration and Particle Deposition on the Radiative Flow of Casson-Micropolar Fluid between Parallel Plates

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Computer Modeling in engineering & Sciences 2025年第1期142卷 665-690页

作者： Ghaliah Alhamzi Badr Saad T.Alkahtani Ravi Shanker Dubey Vinutha Kalleshachar Neelima Nizampatnam department of Mathematics and Statistics College of ScienceImam Mohammad Ibn Saud Islamic University(IMSIU)Riyadh11564Saudi Arabia department of Mathematics College of ScienceKing Saud UniversityRiyadh11989Saudi Arabia department of Mathematics Amity School of Applied SciencesAmity University RajasthanJaipur302002RajasthanIndia department of Studies in Mathematics Davangere UniversityDavangere577002India department of Electronics and Communication engineering Amrita School of EngineeringAmrita Vishwa VidyapeethamBengaluru560035India

Assessing the behaviour and concentration of waste pollutants deposited between two parallel plates is essential for effective environmental *** the effectiveness of treatment methods in reducing pollution scales is made easier by analysing waste discharge *** waste discharge concentration analysis is useful for assessing how effectively wastewater treatment techniques reduce pollution *** study aims to explore the Casson micropolar fluid flow through two parallel plates with the influence of pollutant concentration and thermophoretic particle *** explore the mass and heat transport features,thermophoretic particle deposition and thermal radiation are *** governing equations are transformed into ordinary differential equations with the help of suitable similarity *** Runge-Kutta-Fehlberg’s fourthfifth order technique and shooting procedure are used to solve the reduced set of equations and boundary *** integration of a neural network model based on the Levenberg-Marquardt algorithm serves to improve the accuracy of predictions and optimize the analysis of *** outcomes are displayed to analyze the characteristics of the relevant dimensionless parameters in the current *** reveal that concentration upsurges as the micropolar parameter *** concentration reduces with an upsurge in the thermophoretic *** upsurge in the external pollutant source variation and the local pollutant external source parameters enhances mass *** surface drag force declines for improved values of porosity and micropolar parameters.

关键词： Micropolar fluid thermal radiation porous medium thermophoretic particle deposition waste discharge concentration

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Modeling and Comprehensive Review of Signaling Storms in 3GPP-Based Mobile Broadband Networks:Causes,Solutions,and Countermeasures

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Computer Modeling in engineering & Sciences 2025年第1期142卷 123-153页

作者： Muhammad Qasim Khan Fazal Malik Fahad Alturise Noor Rahman department of Computer Science Iqra National UniversityPeshawar25000Pakistan department of Cybersecurity College of ComputerQassim UniversityBuraydah52555Saudi Arabia department of Computer Science and engineering Al-Fayha CollegeAl Jubayl31961Saudi Arabia

Control signaling is mandatory for the operation and management of all types of communication networks,including the Third Generation Partnership Project(3GPP)mobile broadband ***,they consume important and scarce network resources such as bandwidth and processing *** have been several reports of these control signaling turning into signaling storms halting network operations and causing the respective Telecom companies big financial *** paper draws its motivation from such real network disaster incidents attributed to signaling *** this paper,we present a thorough survey of the causes,of the signaling storm problems in 3GPP-based mobile broadband networks and discuss in detail their possible solutions and *** provide relevant analytical models to help quantify the effect of the potential causes and benefits of their corresponding *** important contribution of this paper is the comparison of the possible causes and solutions/countermeasures,concerning their effect on several important network aspects such as architecture,additional signaling,fidelity,etc.,in the form of a *** paper presents an update and an extension of our earlier conference *** our knowledge,no similar survey study exists on the subject.

关键词： Signaling storm problems control signaling load analytical modeling 3GPP networks smart devices diameter signaling mobile broadband data access data traffic mobility management signaling network architecture 5G mobile communication

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An Unprecedented Efficiency with Approaching 21%Enabled by Additive‑Assisted Layer‑by‑Layer Processing in Organic Solar Cells

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Nano-Micro Letters 2025年第2期17卷 372-375页

作者： Shuai Xu Youdi Zhang Yanna Sun Pei Cheng Zhaoyang Yao Ning Li Long Ye Lijian Zuo Ke Gao Key Laboratory of Advanced Green Functional Materials College of ChemistryChangchun Normal UniversityChangchun 130032People’s Republic of China Shandong Provincial Key Laboratory for Science of Material Creation and Energy Conversion School of Chemistry and Chemical EngineeringShandong UniversityQingdao 266237People’s Republic of China College of polymer Science and engineering Sichuan UniversityChengdu 610065People’s Republic of China State Key Laboratory and Institute of Elemento‑Organic Chemistry Centre of Nanoscale Science and Technology and Key Laboratory of Functional Polymer MaterialsRenewable Energy Conversion and Storage Center(RECAST)College of ChemistryNankai UniversityTianjin 300071People’s Republic of China Institute of polymer Optoelectronic Materials and Devices State Key Laboratory of Luminescent Materials and Devices South China University of TechnologyGuangzhou 510640People’s Republic of China Tianjin Key Laboratory of Molecular Optoelectronic Sciences School of Materials Science and EngineeringTianjin UniversityTianjin 300350People’s Republic of China State Key Laboratory of Silicon Materials MOE Key Laboratory of Macromolecular Synthesis and FunctionalizationDepartment of Polymer Science and EngineeringZhejiang UniversityHangzhou 310027People’s Republic of China

Recently published in Joule,Feng Liu and colleagues from Shanghai Jiaotong University reported a record-breaking 20.8%power conversion efficiency in organic solar cells(OSCs)with an interpenetrating fibril network active layer morphology,featuring a bulk p-in structure and proper vertical segregation achieved through additive-assisted layer-by-layer *** optimized hierarchical gradient fibrillar morphology and optical management synergistically facilitates exciton diffusion,reduces recombination losses,and enhances light capture *** approach not only offers a solution to achieving high-efficiency devices but also demonstrates the potential for commercial applications of OSCs.

关键词： Organic solar cells Additive-assisted layer-by-layer processing Three-dimensional fibril morphology Bulk p-i-n structure Optical management

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WHAT ARE THE DIFFERENCES OF polymer SURFACE RELAXATION FROM THE BULK?

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Chinese Journal of polymer Science 2011年第1期29卷 81-86页

作者： Ian Mann Ryan M.Van Horn Jason J.Ge Matthew J.Graham Frank W.Harris Stephen Z.D.Cheng College of polymer Science and polymer engineering Department of Polymer Sciencethe University of Akron

The polymer surface relaxation in thin films has been a long debating issue. We report a new method on studying surface relaxation behaviors of polymer thin films on a solid substrate. This method involved utilizing a rubbed polyimide surface with a pretilting angle in a liquid crystalline cell. Due to the surface alignment, the liquid crystals were aligned along the rubbing direction. During heating the liquid crystalline cell, we continuously monitored the change of orientation of the liquid crystals. It is understood that at a temperature where the orientation of liquid crystal is lost, the surface relaxation on the glass substrate takes place to lose the polyimide surface orientation. It was found that the relaxation temperature at which the liquid crystals lose their orientation depends on the film thickness of the polyimide. A quantitative linear relationship between the relaxation temperature and reciprocal of the film thickness can be observed. Furthermore, different topologies of the rubbed and relaxed thin films were amplified using the polyethylene decoration method and observed using atomic force microscopy.

关键词： Surface relaxation Liquid crystal orientation Polyethylene decoration.

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