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Influence of graphene nanoplatelet incorporation and dispersion state on thermal, mechanical and electrical properties of biodegradable matrices

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Journal of Materials Science & Technology 2018年第6期34卷 1026-1034页

作者： Sima kashi Rahul k.Gupta Nhol kao S.Ali Hadigheh Sati N.Bhattacharya Institute for Frontier Materials Deakin University Rheology and Materials Processing Group School of Engineering RMIT University School of Civil Engineering Faculty of Engineering and IT The University of Sydney

Graphene nanoplatelets （GNPs） were used as multifunctional nanofiller to enhance thermal and mechanical properties as well as electrical conductivity of two different biodegradable thermoplastics： poly lactide （PLA） and poly （butylene adipate-co-terephthalate）（PBAT）. Morphological investigations showed different levels of GNP dispersion in the two matrices, and consequently physical properties of the two systems exhibited dissimilar behaviours with GNP incorporation. Crystallinity of PLA, determined from differential scanning calorimetry, was observed to increase markedly with addition of GNPs in contrast to the decrease in crystallinity of PBAT. Isothermal and non-isothermal thermogravimetric analyses also revealed a more significant delay in thermal decomposition of PLA upon addition of GNPs compared to that of PBAT. Furthermore, results showed that increasing GNP content of PLA and PBAT nanocomposites influenced their Young＇s modulus and electrical conductivity in different ways. Modulus of PBAT increased continuously with increasing GNP loading while that of PLA reached a maximum at 9wt% GNPs and then decreased. Moreover, despite the higher conductivity of pure PBAT compared to pure PLA, conductivity of PLA/GNP nanocomposites overtook that of PBATIGNP nanocomposites above a certain GNP concentration. This demonstrated the determining effect of nanoplatelets dispersion state on the matrices properties.

关键词： Graphene Nanocomposite Poly lactide Poly butylene adipate-co-terephthalate Thermal stability Electrical conductivity Properties

Potential Oscillations of a Stainless Steel Electrode during Galvanostatic Polarization in a Mixed Solution of Sulfuric and Chromic Acids

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International Journal of Minerals,Metallurgy and Materials 1998年第3期12卷 134-139页

作者： k Ogura W Lou M Nakayama T Fukume(Department of Applied Chemistry, Yamaguchi University, Ube 755, Japan Department of Applied Chemistry Yamaguchi University Ube 755 Japan

Potential oscillations of a stainless steel electrode galvanostatically anodized have been observed in amixture of chromic and sulfuric acids. The potential regularly oscillated between 1.6 V vs. SCE (lower) and 2.1V(upper) with a certain frequency. The potential values are affected neither by the composition of chromic and sulfu-ric acids nor by the magnitude of applied current density although the potential frequency is very sensitive to theseparameters. This phenomenon is interpreted in terms of the repeated formation and disappearance of the saturatedlayer of dichromate ions on the electrode surface. Such scheme is consistent with the in situ FTIR spectroscopicresult that the concentration of Cr2O ions on the electrode surface increased with time during the polarization atthe lower potential but the change in concenetion of Cr2O ions was negligible at the higher potential.

关键词： stainless steel electrode potential galvanostatic polarization

Hemodynamic effects of propranolol with spironolactone in patients with variceal bleeds: A randomized controlled trial

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World Journal of Gastroenterology 2008年第12期14卷 1908-1913页

作者： Binay k De Deep Dutta Rimi Som Pranab k Biswas Subrata k Pal Anirban Biswas Department of Medicine Medical College Calcutta 88 College Street Calcutta 700073 and Institute of Cardiovascular Sciences RG Kar Medical College Calcutta 32 Gorachand Road Kolkata 700014 India

AIM: To study the hemodynamic effects of spironolactone with propranolol vs propranolol alone in the secondary prophylaxis of variceal bleeding. METHODS: Thirty-five cirrhotics with variceal bleeding randomly received propranolol (n = 17: Group A) or spironolactone plus propranolol (n = 18: Group B). Hemodynamic assessment was performed at baseline and on the eighth day. RESULTS: Spironolactone with propranolol caused a greater reduction in the hepatic venous pressure gradient than propranolol alone (26.94% vs 10.2%; P < 0.01). Fourteen out of eighteen patients on the combination treatment had a reduction in hepatic venous pressure gradient to ≤ 12 mmHg or a 20% reduction from baseline in contrast to only six out of seventeen (6/17) on propranolol alone (P < 0.05). CONCLUSION: Spironolactone with propranolol results in a better response with a greater reduction in hepatic venous pressure gradient in the secondary prophylaxis of variceal bleeding. A greater number of patients may be protected by this combination therapy than by propranolol alone. Hence, this combination may be recommended for secondary prophylaxis in patients with variceal bleeding.

关键词： Hepatic venous pressure gradient Secondary prophylaxis Spironolactone Propranolol Varicealbleeding

Evaluation of SIFOM-FVCOM system for high-fidelity simulation of small-scale coastal ocean flows

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Journal of Hydrodynamics 2016年第6期28卷 994-1002页

作者： k.QU H.S.TANG A.AGRAWAL C.B.JIANG B.DENG Department of Civil Engineering City College City University of New York School of Hydraulic Engineering Changsha University of Sciences and Technology

This paper evaluates the SIFOM-FVCOM system recently developed by the authors to simulate multiphysics coastal ocean flow phenomena, especially those at small scales. First, its formulation for buoyancy is examined with regard to solution accu- racy and computational efficiency. Then, the system is used to track particles in circulations in the Jamaica Bay, demonstrating that large-scale patterns of trajectories of fluid particles are sensitive to small-scales flows from which they are released. Finally, a simulation is presented to illustrate the SIFOM-FVCOM system＇s capability, which is beyond the reach of other existing models, to directly and simultaneously model large-scale storm surges as well as small-scale flow structures around bridge piers within the Hudson River during the Hurricane Sandy.

关键词： coastal ocean flow multiscale multiphysics hybrid method domain decomposition SIFOM-FVCOM system

Theoretical investigation of sulfur defects on structural, electronic,and elastic properties of ZnSe semiconductor

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Chinese Physics B 2015年第7期24卷 365-370页

作者： Muhammad Zafar Shabbir Ahmed M.Shakil M.A.Choudhary k.Mahmood Simulation Laboratory Department of PhysicsThe Islamia University of Bahawalpur 63100Pakistan Department of Physics GC UniversityFaisalabad 68000Pakistan

The structural, electronic, and elastic properties of ZnSe1-xSx for the zinc blende structures have been studied by using the density functional theory. The calculations were performed using the plane wave pseudopotential method, as implemented in Quantum ESPRESSO. The exchange-correlation potential is treated with the local density approximation pz-LDA for these properties. Moreover, LDA＋U approximation is employed to treat the ＂d＂ orbital electrons properly. A comparative study of the band gap calculated within both LDA and LDA＋U schemes is presented. The analysis of results show considerable improvement in the calculation of band gap. The inclusion of compositional disorder increases the values of all elastic constants. In this study, it is found that elastic constants C11, C12, and C44 are mainly influenced by the compositional disorder. The obtained results are in good agreement with literature.

关键词： first principles calculations density functional theory II–VI semiconductors electronic and elastic properties

Understanding Bonding Nature of α-keggin Polyoxometalates[XW_(12)O_(40)]^(n−)(X=Al,Si,P,S):A Generalized Superatomic Perspective

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Energy & Environmental Materials 2024年第6期7卷 176-183页

作者： Rui Li Yulei Shi Famin Yu Rui Wang Haitao Yan Boon k.Teo Zhigang Wang Department of Physics Capital Normal UniversityBeijing 100048China key Laboratory of Material Simulation Methods&Software of Ministry of Education College of PhysicsJilin UniversityChangchun 130012China Institute of Atomic and Molecular Physics Jilin UniversityChangchun 130012China State key Laboratory for Physical Chemistry of Solid Surfaces College of Chemistry and Chemical EngineeringXiamen UniversityXiamen 361005China Institute of Theoretical Chemistry College of ChemistryJilin UniversityChangchun 130012China

α-keggin polyoxometalates(POMs)[XW_(12)O_(40)]^(n−)(X=Al,Si,P,S)are widely used in batteries owing to their remarkable redox ***,the mechanism underlying the applications appears inconsistent with the widely accepted covalent bonding ***,first-principles calculations show that XW_(12)are core–shell structures composed of a shell and an XO_(4)^(n−)core,both are stabilized by covalent ***,owing to the presence of a substantial number of electrons in W_(12)O_(36)shell,the frontier molecular orbitals of XW_(12)are not only strongly delocalized but also exhibit superatomic properties with high-angular momentum electrons that do not conform to the Jellium *** analysis indicates that energetically high lying filled molecular orbitals(MOs)have reached unusually high-angular momentum characterized by quantum number k or higher,allowing for the accommodation of numerous *** attribute confers strong electron acceptor ability and redox activity to XW_(12).Moreover,electrons added to XW_(12)still occupy the k orbitals and will not cause rearrangement of the MOs,thereby maintaining the stability of these *** findings highlight the structure–activity relationship and provide a direction for tailor-made POMs with specific properties at atomic level.

关键词： first principles molecular orbital polyoxometalate redox activity superatom

Artificial neural network approach to assess selective flocculation on hematite and kaolinite

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International Journal of Minerals,Metallurgy and Materials 2014年第7期21卷 637-646页

作者： Lopamudra Panda P.k.Banerjee Surendra kumar Biswal R.Venugopal N.R.Mandre R&D Tata Steel Limited Institute of Minerals and Materials Technology(Council of Scientific and Industrial Research) Department of Fuel & Minerals Engineering Indian School of Mines University

Because of the current depletion of high grade reserves, beneficiation of low grade ore, tailings produced and tailings stored in tailing ponds is needed to fulfill the market demand. Selective flocculation is one alternative process that could be used for the beneficiation of ultra-fine material. This process has not been extensively used commercially because of its complex dependency on process parameters. In this paper, a selective flocculation process, using synthetic mixtures of hematite and kaolinite in different ratios, was attempted, and the ad-sorption mechanism was investigated by Fourier transform infrared （FTIR） spectroscopy. A three-layer artificial neural network （ANN） model （4？4？3） was used to predict the separation performance of the process in terms of grade, Fe recovery, and separation efficiency. The model values were in good agreement with experimental values.

关键词： hematite kaolinite flocculation artificial neural networks back propagation algorithm Fourier transform infrared spectroscopy separation efficiency

A new four-dimensional hyperjerk system with stable equilibrium point, circuit implementation, and its synchronization by using an adaptive integrator backstepping control

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Chinese Physics B 2018年第10期27卷 231-239页

作者： J P Singh V T Pham T Hayat S Jafari F E Alsaadi B k Roy Department of Electrical Engineering National Institute of Technology Silchar 788010 India School of Electronics and Telecommunications Hanoi University of Science and Technology 01 Dai Co Viet Hanoi Viet Nam Department of Mathematics Faculty of Science King Abdulaziz University Jeddah 21589 Saudi Arabia Department of Mathematics Quaid-I-Azam University Islamabad 44000 Pakistan Ambikar University of Technology Tehran 15875-4413Iran Department of Information Technology Faculty of Computing and IT King Abdulaziz University Jeddah Saudi Arabia

This paper reports a new simple four-dimensional（4 D） hyperjerk chaotic system. The proposed system has only one stable equilibrium point. Hence, its strange attractor belongs to the category of hidden attractors. The proposed system exhibits various dynamical behaviors including chaotic, periodic, stable nature, and coexistence of various attractors. Numerous theoretical and numerical methods are used for the analyses of this system. The chaotic behavior of the new system is validated using circuit implementation. Further, the synchronization of the proposed systems is shown by designing an adaptive integrator backstepping controller. Numerical simulation validates the synchronization strategy.

关键词： new hyperjerk chaotic system stable equilibrium hidden attractors adaptive backstepping control synchronization

New methods for identification of disinfection byproducts of toxicological relevance: Progress and future directions

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Journal of Environmental Sciences 2021年第1期33卷 151-159页

作者： Nicholas J.P.Wawryk Caley B.Craven Lindsay k.Jmaiff Blackstock Xing-Fang Li Division of Analytical and Environmental Toxicology Department of Laboratory Medicine and PathologyFaculty of Medicine and DentistryUniversity of AlbertaEdmontonABT6G 2G3Canada

Disinfection byproducts(DBPs)represent a ubiquitous source of chemical exposure in disinfected *** over 700 DBPs have been identified,the drivers of toxicity remain poorly ***,ever evolving water treatment practices have led to a continually growing list of *** of analytical technologies have enabled the identification of new classes of DBPs and the quantification of these chemically diverse sets of *** we summarize advances in new workflows for DBP analysis,including sample preparation,chromatographic separation with mass spectrometry(MS)detection,and data *** aid in the selection of techniques for future studies,we discuss necessary considerations for each step in the *** review focuses on how each step of a workflow can be optimized to capture diverse classes of DBPs within a single ***,we highlight new MS-based approaches that can be powerful for identifying novel DBPs of toxicological *** discuss current challenges and provide perspectives on future research directions with respect to studying new DBPs of toxicological *** analytical technologies continue to advance,new strategies will be increasingly used to analyze complex DBPs produced in different treatment processes with the aim to identify potential drivers of toxicity.

关键词： Water disinfection byproducts(DBPs) Emerging contaminants Mass spectrometry Chromatography Nontargeted analysis Toxicity drivers