FABRICATION OF CARBON NANOSTRUCTURES BY LASER ASSISTED CHEMICAL REACTION

NANO ◽  
2006 ◽  
Vol 01 (01) ◽  
pp. 73-76 ◽  
Author(s):  
JONGBOK PARK ◽  
SUNGHO JEONG ◽  
OK HWAN CHA ◽  
MUN SEOK JEONG ◽  
DO-KYEONG KO ◽  
...  

In this work, a simple method is reported for the synthesis of bundles of carbon nanostructures under room temperature and atmospheric pressure. A pulsed Nd:YAG laser (355 nm, 10 Hz) is focused into the mixture of ferrocene and xylene solutions to produce the nanostructures in which ferrocene plays the role of a catalyst while xylene is the carbon source for nanostructure growth. During the period of irradiation, the color of solution turns into dark brown from transparent orange. Upon the completion of irradiation, typically for an hour, a variety of bundles of carbon nanostructures are found in the solution. Raman spectroscopy, scanning electron microscopy (SEM), and transmission electron microscopy (TEM) are used to investigate the nanostructures.

2013 ◽  
Vol 750-752 ◽  
pp. 336-339
Author(s):  
Fa Chao Wu ◽  
Teng Fei Shen

In this work, CaCO3 nanoparticles have been synthesized via heat-treatment of a new precursor. Effect of calcinations temperature on particle size has been investigated. The products were characterized by Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). nanoCaCO3 was modified using chloroform as solvent and fatty acid as modifier atroom temperature. The advantage of this modification is that it can be proceed at room temperature and it can reduce energy consumption.


2012 ◽  
Vol 602-604 ◽  
pp. 183-186 ◽  
Author(s):  
Jing Liu ◽  
Rong Wu ◽  
Jin Li ◽  
Yan Fei Sun ◽  
Ji Kang Jian

In this paper, we report the synthesis of cubic silicon carbide (3C-SiC) nanoparticles by direction reaction of silicon powders and carbon nanotubes. The as-prepared SiC nanoparticles were characterized by X-ray powder diffraction, scanning electron microscopy, transmission electron microscopy and Raman scattering at room temperature. The possible growth mechanism is proposed.


2014 ◽  
Vol 1035 ◽  
pp. 488-491
Author(s):  
Jing Jing Li ◽  
Yun Zhao ◽  
Han Sheng Li ◽  
Qin Wu ◽  
Qing Ze Jiao

Hollow nickel ferrite microspheres with a diameter of about 1.5 to 2.5 μm were synthesized using an emulsion-based solvothermal method in combination with calcination at 550°C. The structures and morphologies of the nickel ferrite microspheres were characterized using an X-ray diffractometer, a transmission electron microscopy and a field emission scanning electron microscopy. Magnetization measurement was carried out using a vibrating sample magnetometer at room temperature. The saturation magnetization and coercivity of nickel ferrite microspheres could reach 19.41 emu/g and 202.28 Oe, respectively. Hollow nickel ferrite microspheres might be used as catalysts, magnetic materials and microwave absorbers.


2012 ◽  
Vol 535-537 ◽  
pp. 571-575
Author(s):  
Xiao Liu ◽  
Long Mei Wang

In this paper, the effect of N addition on mechanical properties of 21Cr-11Ni austenitic heat-resisting stainless steel was investigated. Scanning electron microscopy was used to study the fracture surfaces in the steels. N in 21Cr–11Ni heat-resisting steel can play a role of stabling austenite and ensuring the structure and mechanical properties in high temperatures. Fracture is changed from cleavage to ductile fracture to 21Cr–11Ni heat-resisting steel, and the strength of test steel are improved at room temperature by adding N, the tensile strength is increased by 8.33%. And the creep rupture strength is improved. The fracture time of the steel containing 0.2% N is 3.2 times higher than the steel containing 0.14% N at 1144K.


Author(s):  
Robert W. Weise

The role that scanning electron microscopy (SEM) is playing in descriptive helminthology is becoming more apparent in the literature. However, the majority of papers on the SEM of helminths have used conventional or modified light microscope techniques of fixation and dehydration, and not established SEM techniques in which freeze- and critical point-drying are routinely used. The present investigation was undertaken to examine the applicability of modified scanning and transmission electron microscope techniques for the preparation of certain helminths for SEM.Method I.– Live animal-parasitic nematodes were fixed in 6% phosphate buffered glutaraldehyde for 24 hr at room temperature.


1995 ◽  
Vol 402 ◽  
Author(s):  
K. A. Gesheva ◽  
G. I. Stoyanov ◽  
D. S. Gogova ◽  
G. D. Beshkov

AbstractWsi2 films were prepared by rapid thermal annealing (RTA) in the temperature range of 800 -1400 °C for time durations of 15 sec -3 minutes. In some of the treatment experiments different gases were involved and a conclusion is made about the role of hydrogen favoring Wsi crystal phase growing at 800 °C. W films with thichnesses in the range 200 Å - 1000 Å were deposited on monocrystalline Si by pyrolitical decomposition of W(CO)6 in CVD reactor at atmospheric pressure and argon atmosphere. Reflection High Energy Electron Diffraction (RHEED) and Scanning Electron Microscopy (SEM) technics were used for structural characterization and FPP-100 device for resistance measurements. Results show that by solid state reaction applied at different RTA processes WSi2 phase could be formed.Resistivities as low as 2-3 mΩ.cm are obtained for 800 -1000 °C.


2010 ◽  
Vol 8 (2) ◽  
pp. 434-439 ◽  
Author(s):  
Junhao Zhang ◽  
Ling Yang ◽  
Xiaofang Cheng ◽  
Jinmeng Zhang ◽  
Fucai Li

AbstractHierarchical nickel microwires with nanothorns were fabricated through a reduction of nickelous salt with hydrazine in diethanolamine. The product was characterized by X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), and energy-dispersive X-ray spectroscopy (EDS). The growth mechanism of the nickel microwires with nanothorns is proposed, based on the evolution of the structures and morphologies, which could be ascribed to the cooperative effect of the complexant of diethanolamine and inherent magnetic interactions. Magnetic properties of the product were measured at room temperature and compared with other shaped counterparts.


2009 ◽  
Vol 81 (12) ◽  
pp. 2317-2325 ◽  
Author(s):  
Wei-De Zhang ◽  
Jin Chen

Strongly bonded arrays of vertically aligned, multi-walled carbon nanotubes (MWNTs) have been successfully grown on Ta foils, and provide a convenient basis for fabricating electrodes with high conductivity and stability. The MWNT arrays were further coated by nanostructured MnO2 through reacting with KMnO4 solution at room temperature. The morphology of the MnO2/MWNT nanocomposite was characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). It was found that the MnO2 is a beehive-like nanostructure that is homogeneously and densely coated on the surface of the MWNTs. The capacitance of the MWNT electrode was significantly increased from 0.14 to 6.81 mF cm–2 after being modified with nanostructured MnO2, that is, the mass-specific capacitance of the bare and MnO2-modified MWNTs was about 33 and 446 F g–1, respectively. The MnO2/MWNT nanocomposite on Ta foils could be potential for developing a supercapacitor.


2003 ◽  
Vol 792 ◽  
Author(s):  
V. Shutthanandan ◽  
Y. Zhang ◽  
C. M. Wang ◽  
J. S. Young ◽  
L. Saraf ◽  
...  

ABSTRACTNucleation of gold nanoclusters in TiO2(110) single crystal using ion implantation and subsequent annealing were studied by Rutherford backscattering spectrometry /channeling (RBS/C), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Approximately 1000 Au2+/nm2 were implanted at room temperature in TiO2(110) substrates. TEM and SEM measurements reveal that rounded nanoclusters were formed during the implantation. In contrast, subsequent annealing in air for 10 hours at 1275 K promoted the formation of faceted (rectangular shaped) Au nanostructures in TiO2. RBS channeling measurements further reveled that Au atoms randomly occupied the host TiO2 lattice during the implantation. However, it appears that some Au atoms moved to the Ti lattice positions after annealing.


2013 ◽  
Vol 774-776 ◽  
pp. 646-649
Author(s):  
Teng Fei Shen ◽  
Ying Juan Sun

In this work, nanoAlumina particles (nanoAl2O3) have been synthesized via solid state reaction. Effect of quantity of surfactant on particle size has been investigated. nanoAl2O3 was modified using chloroform as solvent and fatty acid as modifier at room temperature. The advantage of this modification is that it can be proceed at room temperature and it can reduce energy consumption. The products were characterized by Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM) and transmission electron microscopy (TEM).


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