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Growth of small diameter multi-walled carbon nanotubes by arc discharge process

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Chinese physics B 2014年第3期23卷 412-417页

作者： K.T.Chaudhary j.Ali p.p.Yupapin Institute of Advanced photonics Science (ApSI) Nanotechnology Research Alliance Universiti Teknologi Malaysia 81310Johor Bahru Malaysia Nanoscale Science and Research Alliance (N’SERA) Faculty of Science King Mongkut’s Institute of Technology Ladkrabang

Multi-walled carbon nanotubes （MWCNTs） are grown by arc discharge method in a controlled methane environment. The arc discharge is produced between two graphite electrodes at the ambient pressures of 100 tort, 300 torr, and 500 torr. Arc plasma parameters such as temperature and density are estimated to investigate the influences of the ambient pressure and the contributions of the ambient pressure to the growth and the structure of the nanotubes. The plasma temperature and density are observed to increase with the increase in the methane ambient pressure. The samples of MWCNT synthesized at different ambient pressures are analyzed using transmission electron microscopy, scanning electron microscopy, Raman spectroscopy, Fourier transform infrared spectroscopy, and X-ray diffraction. An increase in the growth of MWCNT and a decrease in the inner tube diameter are observed with the increase in the methane ambient pressure.

关键词： electric discharge arc plasma temperature and density carbon nanotubes

Evaluating Wharton’s jelly-derived stem cell therapy in autism:Insights from a case study

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World journal of Methodology 2025年第2期15卷 174-176页

作者： Muzamil Akhtar Abdulqadir j Nashwan College of Medicine Gujranwala Medical CollegeGujranwala 52250PunjabPakistan Department of Nursing and Midwifery Research Hamad Medical CorporationDoha 3050Qatar

Autism spectrum disorder(ASD)is a complex neurodevelopmental disorder affecting over 2%of the global population,marked by social communication deficits and repetitive *** et al explored the efficacy and safety of Wharton’s jelly-derived mesenchymal stem cell(Wj-MSC)therapy in a 4-year-old child with *** the childhood autism rating scale and Denver II develop-mental screening test,significant improvements were seen after six Wj-MSC sessions,with no adverse events over 2 *** promising results,the study’s single-case design limits ***,multi-center trials are needed to validate the findings and assess long-term effects of Wj-MSC therapy in ASD.

关键词： Autism spectrum disorder Stem cell therapy Neuroinflammation Neuro-developmental disorders Wharton jelly derived mesenchymal stem cell

Induced Morphisms Between Localization Genera of Groups

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Algebra Colloquium 2014年第2期21卷 285-294页

作者： j.C. Mba p.j. Witbooi University of the Western Cape Private Bag X17 7535 Bellville South Africa

For a certain class of groups under a given finite group F, we define and compute genus groups, which coincide with the known genus groups in the case that F＇ is the trivial group. We prove the existence of various induced homomorphisms between genus groups. We discover an induced morphism arising from factoring out a finite normal subgroup.

关键词： localization restricted genus groups under a finite group

ENERGY ESTIMATES FOR DELAY DIFFUSION-REACTION EQUATIONS

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journal of Computational Mathematics 2008年第4期26卷 536-553页

作者： j.A.Ferreira p.M.daSilva CMUC-Departamento Departamento

In this paper we consider nonlinear delay diffusion-reaction equations with initial and Dirichlet boundary conditions. The behaviour and the stability of the solution of such initial boundary value problems （IBVps） are studied using the energy method. Simple numerical methods are considered for the computation of numerical approximations to the solution of the nonlinear IBVps. Using the discrete energy method we study the stability and convergence of the numerical approximations. Numerical experiments are carried out to illustrate our theoretical results.

关键词： Delay diffusion reaction equation Energy method Stability Convergence.

Comeld^TM joints: A Novel Technique for Bonding Composites and Metal

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稀有金属材料与工程 2009年第A3期38卷 134-141页

作者： Tu W Guild F j Hogg p j Queen Mary University of London Imperial College London South Kensington Campus University of Manchester PO Box 88

Current and future structural applications for composite laminates frequently involve design solutions combining composite laminates and metal; the materials must be joined. Two conventional means of joining are available mechanical joining and adhesive bonding. Both methods have critical disadvantages. A novel surface treatment for metals developed at TWI, Surfi-Sculpt, leads to the formation of surface protrusions on metal surfaces. These protrusions are typically 1.0 mm high and 0.6 mm in diameter. The surface modified metal can be bonded with composite laminates to form a Comeld～TM joint. These joints can be described as a combination of mechanical fastening and adhesive bonding. This paper describes our current work using finite element modelling to optimize the protrusions in respect to their geometry and distribution. The simulations require multi-scale modelling techniques to transfer results between the global model of the whole joint and the unit cell models containing a protrusion. Results from the simulations show critical effects on stress distributions arising from changing protrusion geometry. These joints show significant advantages over conventional adhesive joining technologies and their application would allow improved performance for combinations of metal and composite laminates.

关键词：复合材料金属表面处理技术物理性能

Magnetovisual method for monitoring thermal demagnetization of permanent magnets used in magnetostrictive actuators

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journal of Rare Earths 2014年第3期32卷 236-241页

作者： j.Kaleta p.Wiewiórski Institute of Materials Science and Applied Mechanics Wroclaw University of Technology Smoluchowskiego Str. 2550-372 Wrocdaw Poland

The design and measuring potential of the latest generation of the magnetic scanner called Magscanner-Maglab System （MMS） was presented. It enabled the fast acquisition of 3D signals from magnetic sensors and their visualization as digitalized mag- netic images. This system was used for monitoring of a thermal demagnetization process of permanent magnets. The original method and measurement devices were capable for examination of magnetic, mechanical and thermal defects in cylindrical rods made of NdFeB and non-rare earth components. Effectiveness of the method and device was tested for the reference demagnetized magnet dedicated for magnetostrictive actuators.

关键词： permanent magnets thermal and shock demagnetization stereographic projection magnetovision camera rare earths

Sequential storage and release of microdroplets

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Microsystems & Nanoengineering 2021年第5期7卷 151-160页

作者： Zenon Toprakciogl Tuomas p.j.Knowles Centre for Misfolding Diseases Yusuf Hamied Department of ChemistryUniversity of CambridgeLensfield RoadCambridge CB21EWUK Cavendish Laboratory Department of PhysicsUniversity of CambridgeJ J Thomson AvenueCambridge CB3 OHEUK

Droplet microfluidic methods have opened up the possibility of studying a plethora of phenomena ranging from biological to physical or chemical processes at ultra low volumes and high throughput.A key component of such approaches is the ability to trap droplets for observation,and many device architectures for achieving this objective have been developed.A challenge with such approaches is,however,recovering the droplets following their confinement for applications involving further ***,we present a device capable of generating,confining and releasing microdroplets in a sequential *** a combination of experimental and computational simulations,we shed light on the key features required for successful droplet storage and ***,we explore the effect of the flow rate of the continuous phase on droplet release,determining that a critical rate is needed to ensure complete droplet deformation through constrictions holding the droplets in place prior to ***,we find that once released,droplets can be retrieved and collected off *** ability to generate,store and sequentially release droplets renders such a device particularly promising for future applications where reactions may not only be monitored on-chip,but droplets can also be retrieved for further analysis,facilitating new exploratory avenues in the fields of analytical chemistry and biology.

关键词： deformation release render

Recent developments in high-pressure die-cast magnesium alloys for automotive and future applications

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journal of Magnesium and Alloys 2023年第1期11卷 78-87页

作者： Gerry Gang Wang j.p.Weiler Meridian Lightweight Technologies StrathroyOntario N7G 4H6Canada

The use of magnesium alloy high pressure die cast(HpDC)components for structural applications,especially in the automotive and transportation industries,where weight reduction is of a great concern,is *** new applications are developing and existing applications are becoming more complex,there is a need for improved properties from magnesium HpDC *** paper reviews the recent developments in HpDC magnesium alloys for transportation *** to the conventional HpDC magnesium alloys,***91D,AM50A/AM60B and AE44,these new alloys have one or more of the following properties:higher strength,higher ductility,superior high-temperature properties or higher thermal *** this work,characteristics which are important in product manufacturing or product performance will be evaluated and discussed,including die castability of powertrain component or thin-walled structural component,mechanical properties at elevated temperatures and *** indicate that these alloys have great potentials to be added to the current magnesium HpDC alloy family and being used in actual automotive and other transport applications.

关键词： alloys alloy ductility

Structural and photoluminescence studies of Eu^(3+) doped zinc oxide nanorods prepared by precipitation method

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journal of Rare Earths 2013年第1期31卷 37-43页

作者： partha p.pal j.Manam Department of Applied physics Indian School of Mines

Abstract： Trivalent europium doped zinc oxide （ZnO：Eu3＋） nanocrystals were synthesized via room temperature chemical co-pre- cipitation and they were systematically characterized by means of X-ray diffraction （XRD）, Fourier transform infrared spectroscopy （FTIR） and photoluminescence （pL） spectroscopy. The as-synthesized samples were found to have hexagonal wurtzite coexisted with the intermediate Zn5（OH）sC12·H2O phase, while the single hexagonal phase was facilitated due to the calcinations. The as obtained samples were broadly composed ofnanoflakes while the highly crystalline nanorods were formed due to low temperature annealing of the as-synthesized samples. The crystallite size of the nanoflakes and nanorods （40-90 nm） were extracted from the XRD pattern which was found to be consistent with scanning electron microscopy （SEM） measurements. The photoluminescence （pL） spectra of nanophosphors showed bright red and orange emissions at 618 and 594 nm respectively with efficient broad blue green emis- sion spectrum due to ZnO lattice. Further, a good energy transfer process from ZnO host to Eu3＋ was observed in pL emission and excitation spectra of Eu3＋ doped ZnO ions. In all, the present nanophosphors were found to have great potentiality for bio-appli- cations.

关键词： photoluminescence zinc oxide rare earth europium nanorods nanoflakes