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Propylene Polymerization Catalyzed by Bis(R_3-indenyl) Zirconium Bichloride/Aluminoxane──Synthesis of Metallocenes and Influence ofSolvent Polarity on Polymerization

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Chemical Research in Chinese Universities 2001年第4期17卷 445-451页

作者： yasin tariq FAN Zhi-qiang ZHU Yin-bang FENG Lin-xian Department of Polymer Science and Engineering Zhe Jiang UniversityHangzhou 310027China

Three unbridged metallocenes, bis(2,4,7-Me3-indenyl)zirconium dichloride(1) , bis(2-Me-4, 7-Et2-indenyl)zirconium dichloride (2) and bis (2, 4, 6-Me3-indenyl) zirconium dichloride (3) were synthesized. The effect of solvent polarity on propylene polymerization catalyzed by the metallocenes in the presence of methylaluminoxane(MAO) and triisobutylaluminum(TIBA) was investigated in the toluene/CH2Cl2 mixed solvent. Changing the solvent polarity was found to influence the catalytic activity, polymer molecular weight and stereospecificity of the catalysts. The changes in the position of the substituents on the ligand caused the different responses of the catalyst to the changes in solvent polarity. The isotactic stereosequence of polypropylene was found to increase with the increase in the polarity of the reaction medium.

关键词： Propylene polymerization Metallocene catalyst Solvent effect Polarity

Effect of Polymerization Temperature on Propylene Polymerization with C_s-symmetric Metallocene Catalyst

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Chinese Chemical Letters 2000年第2期11卷 167-170页

作者： Zhi Qiang FAN tariq yasin Lin Xian FENG (Department of Polymer Science and Engineering, Zhejiang University, Hangzhou 310027) Zhejiang Univ Dept Polymer Sci & Engn Hangzhou 310027 Peoples R China

A novel highly active C-s-symmetric metallocene catalyst namely: meso-dimethylsilylbis (2,4,6-trimethyl-1 -indenyl)zirconium dichloride is presented. The effect of polymerization temperature (0-70 degrees C) on the catalyst performance for propylene polymerization has been investigated. This catalyst shows very high activity at 50 degrees C which is higher than the activity of the racemic analogue, and the resulted polypropylene is amorphous in nature with isotactic pentad content [mmmm] of 12 %.

关键词： polymerization metallocene catalyst propylene

STEREOCHEMICAL CONTROL IN PROPYLENE POLYMERIZATION CATALYZED BY UNBRIDGED METALLOCENE CATALYSTS

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Chinese Journal of Polymer Science 2001年第4期19卷 407-413页

作者： Yin-bang Zhu Zhi-qiang Fan tariq yasin Lin-xian Feng Department of Polymer Science and Engineering Zhejiang University Hangzhou 310027, China Zhejiang Univ Dept Polymer Sci & Engn Hangzhou 310027 Peoples R China

Two unbridged metallocene catalysts, bis(2,4,7-trimethylindenyl)zirconium dichloride (met-I) and bis(2,4,6-trimethylindenyl)zirconium dichloride (met-II), which are different in the position of substituents on the six-membered ring of the indenyl ligands were synthesized. The effect of substituents in the two metallocenes on the propylene polymerization was studied in the presence of methylaluminoxane (MAO) and triisobutylaluminium (TIBA). From the analysis of microstructure determined by C-13-NMR, it was demonstrated that the polymers produced by met-II have higher [mmmm] isotactic sequences than that of met-I. Using a mechanism based on model statistical analysis, it was found that chain-end model was dominant for met-I. However, met-II obeys the concurrent two-sites model during polymerization, which can be attributed to the existence of 'racemic-like' conformer in its system.

关键词： unbridged metallocene propylene polymerization elastomeric polypropylene stereochemical mechanism

A Potential Approach to Enhance the Seebeck Coefficient of UHMWPE by Using the Graphene Oxide

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Non-Metallic Material Science 2020年第2期2卷 21-27页

作者： Aqsa Irfan Malik Naqash Mehmood Malik Sajjad Mehmood Arif Aziz Mansoor Ahmad Baluch Muhammad Rizwan tariq yasin Department of Basic Science University of Engineering and TechnologyTaxila47050Pakistan Department of Physics Air University444000IslamabadPakistan Harbin Engineering University HarbinHeilingjiang150001China Department of Chemistry Pakistan Institute of Engineering and Applied Sciences45650IslamabadPakistan

Thermoelectric materials have been a competent source for the production of energy in the present *** most important and potential parameter required for the material to have better thermoelectric characteristics is the Seebeck *** this work,ultra high molecular weight polyethylene(UHMWPE)and graphene oxide(GO)nanocomposites were prepared by mechanical mixing by containing 10000ppm,50000ppm,70000ppm,100000ppm,150000ppm,and 200000ppm loadings of graphene *** to the intrinsic insulating nature of UHMWPE,the value of Seebeck for pristine UHMWPE and its nanocomposites with 10000ppm&50000ppm of GO concentration was too low to be ***,the Seebeck coefficient for composites with 70000ppm,100000ppm,150000ppm,and 200000ppm loadings of GO was found to be 180,206,230,and 235μV/K,*** higher values of Seebeck coefficients were attributed to the superior thermal insulating nature of UHMWPE and the conductive network induced by the GO within the UHMWPE insulating ***,the values of the figure of merit and power factor were negligibly small due to the lower concentration of charge carriers in UHMWPE/GO nanocomposites but still reported,results are extremely hopeful for considering the composite as the potential candidate for thermoelectric applications.

关键词： UHMWPE Graphene oxide Electrical conductivity Thermal conductivity Seebeck coefficient Figure of merit

The thermoanalytical, infrared and pyrolysis-gas chromatography-mass spectrometric sifting of poly (methyl methacrylate) in the presence of phosphorus tribromide

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Natural Science 2010年第4期2卷 307-319页

作者： Muhammad Arshad Khalid Masud Muhammad Arif Saeed-ur Rehman Jamshed H. Zaidi Muhammad Arif Aamer Saeed tariq yasin 不详

The behaviour of poly(methyl methacrylate) was examined in the presence of phosphorus tri-bromide (PBr3) with varying concentrations. Films were cast from common solvent and subjected to TG, DTA, DTG, IR and Py-GC-MS for evaluating the degradation routes. Despite early decomposition of the blends, certain tempera-ture zones were identified for stabilization of the system. New products were found and mecha-nisms of their formation were proposed. Pyro-lysis of the blends was also carried out at dif-ferent temperatures to ascertain the nature of interaction between the constituents of the system.

关键词： PMMA PBr3 Thermoanalytical Study IR Spectroscopy GC-MS Investigation

The thermoanalytical, infrared and pyrolysis-gas chromatography-mass spectrometric sifting of poly (methyl methacrylate) in the presence of phosphorus tribromide

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Physical,Thermal and Partial Discharge Evaluation of Nano Alumina Filled Silicone Rubber in an Inclined Plane Test

Natural Science 2010年第4期

作者： Muhammad Arshad Khalid Masud Muhammad Arif Saeed-ur Rehman Jamshed H. Zaidi Muhammad Arif Aamer Saeed tariq yasin

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CSEE Journal of Power and Energy Systems 2022年第4期8卷 1242-1249页

作者： M.tariq Nazir Faizan Tahir Butt Haider Hussain B.Toan Phung Shakeel Akram M.Shoaib Bhutta Ghulam yasin School of Engineering RMIT UniversityMelbourneVIC 3000Australiaand the School of Mechanical and Manufacturing EngineeringUniversity of New South Wales SydneyNSW 2052Australia School of Electrical Engineering and Telecommunications University of New South Wales SydneyNSW 2052Australia Institut d'Electronique et des Systès(IES) UMR 5214CNRSUniversitéde Montpellier34095 MontpellierFrance State Key Laboratory of Power Transmission Equipment and System Security and New Technology Chongqing UniversityChonging 400044China State Key Laboratory of Chemical Resource Engineering College of EnergyBeijing University of Chemical TechnologyBeijing 100029China

Silicone rubber(SiR)composite material is a modern-day insulator for high voltage outdoor *** imperfection attributed to SiR is its weak resistance to tracking and erosion when exposed to an outdoor polluted environment which reduces its operational *** paper investigates the performance of SiR with the addition of 0,1,2.5,5,10 and 20%by weight contents of nano alumina(Al_(2)O_(3)).Inclined plane tests are performed according to IEC 60587 using the step up tracking voltage method with an initial voltage of 3.0 kV and the contaminant solution flow rate is maintained at 0.3 ml/min using a peristaltic *** applied voltage level is increased at a rate of 0.25 kV/*** suggest that physical tracking,erosion,RMS leakage current and surface partial discharge(PD)performance of samples is improved with the addition of nano *** tracking length,eroded mass,RMS leakage current and average PD magnitude are measured 22%,79%,30%and 52%lesser in 20 wt%relative to 0 wt%,respectively.A thermal distribution analysis is undertaken with infrared camera and it is discovered that heat is accumulated in the discharge area of the liquid *** maximum temperature on the insulating specimen is decreased with increasing nanofiller *** above promising findings can be due to better thermal stability with low chain mobility at the interaction zone of SiR and ***,less liquid evaporation due to better thermal conduction and improved physical bonding between SiR and nano alumina are possible reasons behind the excellent performance of nanocomposites.

关键词： Alumina(Al_(2)O_(3)) dry band arcing(DBA) inclined plane test(IPT) infrared thermal analysis leakage current partial discharge(PD) silicone rubber(SiR) thermal properties

Synthesis and Structural Investigations of New 4-Hexyl-1-(4-nitrophenyl)-1-H-1,2,3-triazole:An Experimental and Theoretical Insight

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Chinese Journal of Structural Chemistry 2015年第12期34卷 1830-1840页

作者： MUHAMMAD Naeem Ahmed KHAWAJA Ansar yasin tariq Mahmood FATIMA Wasim MUHAMMAD Haleem Khan M.NAWAZ Tahir SAFEENA Zafar SHAISTA Anjum Department of Chemistry The University of Azad Jammu and Kashmir Department of Chemistry COMSATS Institute of Information Technology Department of Chemistry Women University Bagh Azad Kashmir Department of Physics University of Sargodha

The title compound, 4-hexyl-1-（4-nitrophenyl）-1-H-1,2,3-triazole （CI4HIsN402）, was synthesized using one-pot strategy via click reaction and the structure was characterized mainly by single-crystal X-ray diffraction, NMR, FT-IR and MS. C14H18N4O2 was crystallized from an EtOH/EtOAc solution in triclinic system, space group PI, with a = 5.3679（3）, b = 7.5499（5）, c = 17.5534（11） A, a = 92.360（4）, β = 90.359（4）, γ = 98.864（4）°, V （A3） = 702.24（8）, Z = 2, crystal size （mm） = 0.42 × 0.26 × 0.18, Rint = 0.096. Packing diagram indicates that there is dimeric interaction between two units via N（3）...H（6）. The crystal structure of the title compound （1） is stabifized by intermolecular interactions. In addition, X-ray analys!s also reveals C-H…π and π-π interactions in the molecule. Theoretical investigations were performed by using Gaussian 09 software at the B3LYP/6, 31G （d,p）level of density,finctional theory （DFT）.to compare the theoretical results with the experimental and to probe structural properties. The molecular electrostatic potential （MEP） mapped over the entire stabilized geometry of the molecule indicated their chemical reactivities. Furthermore, frontier molecular orbital （electronic properties） was computed at the same level of DFT as used. forenergy minima structure.

关键词： click chemistry disubstituted triazole X-ray DFT MEP frontier molecurar orbital

Automated Speech Recognition System to Detect Babies’ Feelings through Feature Analysis

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Computers, Materials & Continua 2022年第11期73卷 4349-4367页

作者： Sana yasin Umar Draz tariq Ali Kashaf Shahid Amna Abid Rukhsana Bibi Muhammad Irfan Mohammed A.Huneif Sultan A.Almedhesh Seham M.Alqahtani Alqahtani Abdulwahab Mohammed Jamaan Alzahrani Dhafer Batti Alshehri Alshehri Ali Abdullah Saifur Rahman Faculty of Computing University of OkaraOkara57000Pakistan Department of Computer Science University of SahiwalSahiwal57000PunjabPakistan Computer Science Department COMSATS University IslamabadLahore Campus57000Pakistan Department of Computer Science CUISahiwal CampusSahiwal57000Pakistan Electrical Engineering Department College of EngineeringNajran University Saudi ArabiaNajran61441Saudi Arabia Pediatric Department Medical CollegeNajran University Saudi ArabiaNajran61441Saudi Arabia Consultant of ORL&HNs and Facial Plastic Surgery College of MedicineNajran University Saudi ArabiaNajran61441Saudi Arabia

Diagnosing a baby’s feelings poses a challenge for both doctors and parents because babies cannot explain their feelings through expression or *** the emotions of babies and their associated expressions during different sensations such as hunger,pain,etc.,is a complicated *** infancy,all communication and feelings are propagated through cryspeech,which is a natural *** clinical methods can be used to diagnose a baby’s diseases,but nonclinical methods of diagnosing a baby’s feelings are *** such,in this study,we aimed to identify babies’feelings and emotions through their cry using a nonclinical *** in the cry sound can be identified using our method and used to assess the baby’s *** considered the frequency of the cries from the energy of the *** feelings represented by the infant’s cry are judged to represent certain sensations expressed by the child using the optimal frequency of the recognition of a real-world audio *** used machine learning and artificial intelligence to distinguish cry tones in real time through feature *** experimental group consisted of 50%each male and female babies,and we determined the relevancy of the results against different *** application produced real-time results after recognizing a child’s cry *** novelty of our work is that we,for the first time,successfully derived the feelings of young children through the cry-speech of the child,showing promise for end-user applications.

关键词： Cry-to-speak machine learning artificial intelligence cry speech detection babies