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Surface charge induced tuning of electrical properties of CVD assisted graphene and functionalized graphene sheets

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Journal of materials Science & Technology 2019年第1期35卷 151-158页

作者： Manash Jyoti Deka Devasish Chowdhury material Nanochemistry Laboratory Physical Sciences Division Institute of Advanced Study in Science and Technology

We demonstrate a new approach to tune the electrical properties of graphene and functionalized graphene. Graphene was synthesized using thermal chemical vapour deposition(TCVD) method on copper foil using precursor gas acetylene and co-catalyst H2 gas. TCVD assisted graphene was successfully transferred onto a silicon wafer. Transferred graphene sheet was then functionalized to prepare graphene oxide(GO) and reduced graphene oxide(rGO). Different surface charge carbon nanoparticles, e.g. carbon nanoparticle with net positive charge and carbon nanoparticle with net negative charge were then immobilized on transferred graphene and functionalized graphene sheets. The functionalized graphene and charge mobilized functionalized graphene were characterized by Uv–vis spectroscopy,Fourier transformed infrared spectroscopy, scanning electron microscopy, and Raman spectroscopy. After immobilization of carbon nanomaterials, the ac electrical conductivity was found to increase due to enhancement of the surface charge, electron density, and mobility. It was observed that negative surface charge immobilized graphene and functionalized graphene show higher conductivity. Thus, the electrical property of graphene and functionalized graphene can be tuned by surface modification with different surface charge carbon nanomaterials.

关键词： Graphene Chemical Vapour Deposition (CVD) Surface charge

An Experimental study of Carbon Dioxide Condensation in Mini Channels

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Journal of Thermal Science 2004年第4期13卷 358-365页

作者： Shigeru KOYAMA Institute of advanced material study Kyushu University Kasuga-koen 6-1 Kasuga-shi Fukuoka 816-8580Japan

In this study, the local characteristics of pressure drop and heat transfer were investigated experimentally for carbon dioxide condensation in a multi-port extruded aluminum test section, which had 10 circular channels each with 1.31 mm inner diameter. The CO2 was cooled with cooling water flow inside the copper blocks that were attached at both sides of the test section. The temperatures at the outer surface of the test section were measured with 24 K-type thermocouples embedded in the upper and lower surfaces along the length. Local heat fluxes were measured with 12 heat flux sensors to estimate the local enthalpies, temperatures and heat transfer coefficients. Bulk mean temperatures of CO2 at the inlet and outlet of the test section were measured with 2 K-type thermocouples. The measurements were performed for the pressure ranged from 6.48 to 7.3 MPa, inlet temperature of CO2 from 21.63 to 31.33℃, heat flux from 1.10 to 8.12 kW/m2, mass velocity from 123.2 to 315.2 kg/m2s, and vapor quality from 0 to 1. The results indicate that pressure drop is very small along the test section, heat transfer coefficient in the two-phase region is higher than that in the single-phase, and mass velocity has important effect on condensation heat transfer characteristics. In addition, experimental data were compared with previous correlations and large discrepancies were observed.

关键词： carbon dioxide condensation heat transfer pressure drop mini channels.

Structural Characterization and Property study on the Activated Alumina-activated Carbon Composite material

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Chinese Journal of Structural Chemistry 2012年第3期31卷 315-320页

作者：陈燕青吴任平叶先锋 College of material Science and Engineering Fuzhou University

AlCl3,NH3·H2O,HNO3 and activated carbon were used as raw materials to prepare one new type of activated alumina-activated carbon composite *** influence of heat treatment conditions on the structure and property of this material was discussed;The microstructures of the composite material were characterized by XRD,SEM,BET techniques;and its formaldehyde adsorption characteristic was also *** results showed that the optimal heat treatment temperature of the activated alumina-activated carbon composite material was 450 ℃,iodine adsorption value was 441.40 mg/g,compressive strength was 44 N,specific surface area was 360.07 m2/g,average pore size was 2.91 nm,and pore volume was 0.26 m3/*** to the BET pore size distribution diagram,the composite material has dual-pore size distribution structure,the micro-pore distributes in the range of 0.6-1.7 nm,and the meso-pore in the range of 3.0-8.0 *** formaldehyde adsorption effect of the activated alumina-activated carbon composite material was excellent,much better than that of the pure activated carbon or activated alumina,and its saturated adsorption capacity was 284.19 mg/g.

关键词： activated carbon activated alumina composite material formaldehyde adsorption

Effect of E × B electron drift and plasma discharge in dc magnetron sputtering plasma

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Chinese Physics B 2011年第1期20卷 435-443页

作者： Sankar Moni Borah Arup Ratan Pal Heremba Bailung Joyanti Chutia Plasma Physics Laboratory Material Sciences DivisionInstitute of Advanced Study in Science and TechnologyPaschim BoragaonGuwahati - 781035AssamIndia

study of electron drift velocity caused by E ×B motion is done with the help of a Mach probe in a dc cylindrical magnetron sputtering system at different plasma discharge parameters like discharge voltage, gas pressure and applied magnetic field strength. The interplay of the electron drift with the different discharge parameters has been investi- gated. Strong radial variation of the electron drift velocity is observed and is found to be maximum near the cathode and it decreases slowly with the increase of radial distance from the cathode. The sheath electric field, E measured experimentally from potential profile curve using an emissive probe is contributed to the observed radial variation of the electron drift velocity. The measured values of the drift velocities are also compared with the values from the con- ventionM theory using the experimental values of electric and magnetic fields. This study of the drift velocity variation is helpful in providing a useful insight for determining the discharge conditions and parameters for sputter deposition of thin film.

关键词： electron drift velocity Mach probe cylindrical magnetron sputtering

Recasting theory of elasticity with micro-finite elements

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Acta Mechanica Sinica 2015年第5期31卷 679-684页

作者： Wennan Zou Institute for advanced study Nanchang University

In the classical theory of elasticity,a body is initially modeled as a homogeneous and dense assemblage of constituent ＂material particles＂.The kernel concept of elastic deformation is the displacement of the particle that associates the current configuration with the reference *** this paper,we exploit an alternative constituent ＂micro-finite element＂,and use the stretch of the element as the essential quality to recast the theory of *** should be realized that such a treatment means that the elastic body can be modeled as a finite covering of elements and consequently characterized by a *** recasting of the elasticity theory becomes more feasible for dealing with defects and topological evolution.

关键词： Micro-finite element Stretch Displacement Relative rotation Compatibility condition

Asymmetric Diels-Alder Reaction of 1-(S_R)-p-Tolylsulfinyl-3-penten-2-one with Cyclopentadiene Catalzed by a Chiral Titanium Reagent

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Chinese Chemical Letters 1997年第11期8卷 935-936页

作者： Wen PEI(Department of Chemistry, Yanbian University, Yanji, 133002)Eiji WADA and Shuji KANEMASA (Institute of advanced material study, Kyushu University, Kasugakoen, Kasuga 816, Japan) Department of Chemistry Yanbian University Yanji 133002 China Institute of advanced material study Kyushu University Kasugakoea Kasuga 816 Japan

Double asymmetric Diels-Alder reaction of 1(SR)-p-Tolylsulfinyl-3-penten-2-one with cyclopentadiene using a chiral titanium reagent was performed. The diastereoselectivity dependent on the size of aryl substituent involved in the chiral ligands was discussed Absolute configuration of the cycloadducts was conformed. Dramatic reversal of selectivity is observed.

关键词： p-Tolylsulfinyl-3-penten-2-one with Cyclopentadiene Catalzed by a Chiral Titanium Reagent S_R Asymmetric Diels-Alder Reaction of 1

Synthesis of (4R)-α-Terpineol

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Chinese Chemical Letters 1997年第1期8卷 19-20页

作者： Wen PEI（Department of Chemistry, Yanbian University, Yanji,133002）Eiji Wada and ShuJi Kanemasa(Institute of advanced material study, Kyushu University, Kasugakoen, Kasuga 816,Japan.) Department of Chemistry Yanbian University Yanji 133002 China Institute of advanced material study Kyushu University Kasugakoen Kasuga 816 Japan

(4R) - a-Terpineol, a natural product, was synthesized enantioselectively byan asymmetrical catalised Diels - Alder reaction from - 1 - phenylsulfonyl - 3 - buten - 2 -one with 2 - methyl - 1,3 - butadiene.

关键词： Synthesis of Terpineol

Electromagnetic and microwave absorbing properties of FeCoB powder composites

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Rare Metals 2013年第4期32卷 402-407页

作者： Shen-Gen Zhang Hang-Xin Zhu Jian-Jun Tian De-An Pan Bo Liu Yan-Tao Kang advanced material and Technology Institute University of Science and Technology Beijing

The electromagnetic and microwave absorbing properties of FeCoB powder composites prepared by sin- gle-roller melt-spinning and mechanical milling processes were investigated in this paper. The result indicates that the flake-like powders are obtained. As milling time increases, the flake-like powder particles tend to agglomerate, causing the flake-like powders decrease gradually. The milling time plays an important role in the electromagnetic parameters which relates to the shape and size of the powder particles. The calculation shows that the sample milled for 6 h could achieve an optimal reflection loss of -11.5 dB at 5.8 GHz, with mass fraction of 83 % and a matching thickness of 1.8 mm. The result also indicates that the microwave absorbing properties of the FeCoB powder composites are adjustable by changing their thickness, and can be applied as a thinner microwave absorbing material in the range of 2-8 GHz.

关键词： Fe48Co48B4 powder composites Mechanical milling Electromagnetic parameters Microwave absorbing properties

Strontium ferrite powders prepared from oily cold rolling mill sludge by solid-state reaction method

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Rare Metals 2013年第5期32卷 518-523页

作者： Bo Liu Shen-Gen Zang Jian-jun Tian De-an Pan Hang-Xin Zhu advanced material and Technology Institute University ofScience and Technology Beijing

Oily cold rolling mill （CRM） sludge is one of the pollutants emitted by iron and steel plants. Recycling oily CRM sludge can not only reduce pollution but also bring social and environmental benefits. In this study, using oily CRM sludge as sources of iron oxide, the strontium ferrite powders were synthesized in multiple steps including vacuum distillation, magnetic separation, oxidizing roasting, and solidstate reaction. The optimal technological conditions of vacuum distillation and oxidizing roasting were studied carefully. To consider the effects of Fe203/ SrCO3 tool ratio, calcination temperature, milling time and calcination time on magnetic properties of prepared strontium ferrite powders, the orthogonal experimental method was adopted. The maximum saturation magneti- zation （62.6 mA-m2.g-1） of the synthesized strontium ferrite powders was achieved at the Fe203/SrCO3 mol ratio of 6, 5 h milling time, 1250 ~C calcination temperature, and 1 h calcination time. Strontium ferrite powders syn- thesis method not only provides a cheap, high quality raw material for the production of strontium ferrite powders, but also effectively prevents the environmental pollution.

关键词： Strontium ferrite powders Oily cold rolling mill sludge Solid-state reaction method Recycling