Seamless aqueous arc discharge process for producing graphitic carbon nanostructures

Carbon ◽  
2017 ◽  
Vol 120 ◽  
pp. 83-88 ◽  
Author(s):  
Sejung Kim ◽  
Youngjun Song ◽  
Michael J. Heller
Keyword(s):  
Carbon Nanostructures ◽  
Arc Discharge ◽  
Graphitic Carbon ◽  
Discharge Process

Quantitative Valence-Loss Spectroscopy of Carbon Nanostructures

1999 ◽  
Vol 5 (S2) ◽  
pp. 690-691
Author(s):  
T. Stöeckli ◽  
Z.L. Wang ◽  
J.-M. Bonard ◽  
P. Stadelmann ◽  
A. Châtelain
Keyword(s):  
Dielectric Function ◽  
Carbon Nanostructures ◽  
Arc Discharge ◽  
Spherical Geometry ◽  
Dielectric Medium ◽  
Graphitic Carbon ◽  
Dielectric Tensor ◽  
Carbon Sphere ◽  
Direct Measurements ◽  
Image Position

Carbon tubes or spheres synthesized by arc-discharge are usually mixed with other byproducts, prohibiting direct measurements of their physical properties by the well established optical techniques because a large quantity of pure specimen is required. Electron energy-loss spectroscopy (EELS) is a unique technique that can be applied to probe the electronic structure of a single carbon tube or sphere. In this paper, the classical dielectric response theory is applied to calculate the EELS spectra acquired from a graphitic carbon sphere at various impact parameters. Graphite is an anisotropic dielectric medium whose dielectric function is described by a tensor. A graphitic carbon sphere is composed of concentric graphitic shells whose dielectric tensor in the spherical geometry, under the local response approximation, is given by (Figure 1)where are the dielectric function of graphite for an electric field perpendicular and parallel, respectively, to the c axis. In the non-relativistic approximation, the surface excitation is calculated by [1]

XRD Quantitative Analysis of Cathode Deposition Formed by DC Arc-Discharge in Water

2020 ◽  
Vol 310 ◽  
pp. 118-123
Author(s):  
Erdene Bayanjargal ◽  
Jigmeddorj Vanchinkhuu ◽  
Tserenjav Erdenebat ◽  
Myagmar Otgonbaatar
Keyword(s):  
Arc Discharge ◽  
Stacking Faults ◽  
Weight Fraction ◽  
Graphitic Carbon ◽  
Discharge Process ◽  
Graphite Electrodes ◽  
Ordered Structures ◽  
Pure Graphite ◽  
Graphite Structure ◽  
Dc Arc

In this study, we aimed to estimate the weight fraction of crystalline phases in a cathode deposition formed by DC arc-discharge between graphite electrodes in water via the XRD method and CARBON XS program based on Shi model, which takes into account disorder and stacking faults in a graphite structure. The structural computation of graphitic carbon materials for comparison was done by using CARBON XS according to Shi model. From the study, we observed that the total weight fraction of 2H hexagonal and 3R rhombohedral ordered structures of graphitic carbon decreases from 77.69% to 48.98%, whereas the weight fraction of random shift and stacking faults increases from 22.31% to 51.02% as compared to these parameters belonging to pure graphite structure during the arc-discharge process.

scholarly journals Modeling of formation of carbon cluster groups in electric arc discharge plasma

2018 ◽  
Vol 80 (2) ◽  
pp. 108-113 ◽  
Author(s):  
A. N. Gavrilov
Keyword(s):  
Carbon Nanostructures ◽  
Arc Discharge ◽  
Experimental Studies ◽  
Particle Method ◽  
Cost Effective ◽  
Carbon Cluster ◽  
Collision Integral ◽  
Numerical Calculations ◽  
Plasma Synthesis ◽  
Interelectrode Space

The problem of modeling complex resource-intensive processes of plasma synthesis of carbon nanostructures (CNS) on the basis of mathematical and numerical methods of solution, focused on the use of parallel and distributed computing for processing large amounts of data, allowing to investigate the relationship and characteristics of processes to obtain an effective, cost-effective method of synthesis of CNS (fullerenes, nanotubes), is an actual theoretical and practical problem. This article deals with the problem of mathematical modeling of motion and interaction of charged particles in a multicomponent plasma based on the Boltzmann equation for the synthesis of ONS by thermal sublimation of graphite. The derivation of the collision integral is presented allowing to perform a numerical solution of the Boltzmann - Maxwell equations system with respect to the arc synthesis of CNS. The high order of particles and the number of their interactions involved simultaneously in the process of synthesis of CNS requires significant costs of machine resources and time to perform numerical calculations on the constructed model. Application of the large particle method makes it possible to reduce the amount of computing and hardware requirements without affecting the accuracy of numerical calculations. The use of parallel computing technology on the CPU and GPU with the use of Nvidia CUDA technology allows you to organize all the General-purpose calculations for the developed model based on the graphics processor of the personal computer graphics card, without the use of supercomputers or computing clusters. The results of experimental studies and numerical calculations confirming the adequacy of the developed model are presented. Obtained quantitative characteristics of the total pairwise interactions between the carbon particles and interactions with the formation of clusters of carbon with various types of ties in the plasma of the interelectrode space which are the basis of the synthesized nanostructures. The formation of carbon clusters occurs in the entire interelectrode space of the plasma with different intensity and depends on the process parameters.

scholarly journals Nonlinear Hydraulic Pressure Response of an Improved Fiber Tip Interferometric High-Pressure Sensor

Sensors ◽  
2020 ◽  
Vol 20 (9) ◽  
pp. 2548
Author(s):  
Wei Huang ◽  
Zhe Zhang ◽  
Jun He ◽  
Bin Du ◽  
Changrui Liao ◽  
...  
Keyword(s):  
High Pressure ◽  
Nonlinear Response ◽  
Arc Discharge ◽  
High Sensitivity ◽  
Measurement Range ◽  
Hydraulic Pressure ◽  
Discharge Process ◽  
Pressure Sensitivity ◽  
Diaphragm Thickness ◽  
Order Of Magnitude

We demonstrate a silica diaphragm-based fiber tip Fabry–Perot interferometer (FPI) for high-pressure (40 MPa) sensing. By using a fiber tip polishing technique, the thickness of the silica diaphragm could be precisely controlled and the pressure sensitivity of the fabricated FPI sensor was enhanced significantly by reducing the diaphragm thickness; however, the relationship between the pressure sensitivity and diaphragm thickness is not linear. A high sensitivity of −1.436 nm/MPa and a linearity of 0.99124 in hydraulic pressure range of 0 to 40 MPa were demonstrated for a sensor with a diaphragm thickness of 4.63 μm. The achieved sensitivity was about one order of magnitude higher than the previous results reported on similar fiber tip FPI sensors in the same pressure measurement range. Sensors with a thinner silica diaphragm (i.e., 4.01 and 2.09 μm) rendered further increased hydraulic pressure sensitivity, but yield a significant nonlinear response. Two geometric models and a finite element method (FEM) were carried out to explain the nonlinear response. The simulation results indicated the formation of cambered internal silica surface during the arc discharge process in the fiber tip FPI sensor fabrication.

Dynamic variation of arc discharge and its effect on corrosion direction under current-carrying sliding

2018 ◽  
Vol 233 (3) ◽  
pp. 380-392 ◽  
Author(s):  
Chaoyong Deng ◽  
Jian Yin ◽  
Hongbo Zhang ◽  
Xiang Xiong ◽  
Pei Wang ◽  
...  
Keyword(s):  
Friction Surface ◽  
High Speed ◽  
Friction And Wear ◽  
Arc Discharge ◽  
Capture Rate ◽  
Three Dimensional ◽  
Discharge Process ◽  
Friction Process ◽  
Large Margin ◽  
Dynamic Variation

Current-carrying sliding tests were performed on an HST-100 high-speed multifunction friction and wear tester. Cf/Cu/C composite was used as the pin, and commercial QCr0.5 was employed as the disk. Sliding tests were carried out at a speed of 30 m/s and a load of 70 N under 25 A, 50 A, 75 A, and 100 A, respectively. Light intensity was collected by a photodiode, and the arc discharge process was recorded by a high-speed camera (HX-5) with a capture rate of 20,000 fp/s. The worn surfaces were characterized by a Nova NanoSEM230 scanning electron microscope and a NANO Focus AG three-dimensional topography instrument. The result indicates that arc discharge occurs randomly, both temporally and spatially, as long as the condition is suitable and occurs more at the beginning and end of the friction process. The arc moves constantly along the friction direction to the outlet. Compared to the inlet, the erosion of the outlet is considerably worse. This finding indicates the arc is moving towards the outlet and grows by a large margin when it leaves the friction surface at the outlet end.

As-Quenched ARC Products By bulse - Discharge

2000 ◽  
Vol 6 (S2) ◽  
pp. 54-55
Author(s):  
Y. Murooka ◽  
Y. Maede ◽  
M. Ozaki ◽  
M. Hibino
Keyword(s):  
Steady State ◽  
Arc Discharge ◽  
Electron Bombardment ◽  
Discharge Process ◽  
Arc Plasma ◽  
Growth Mechanisms ◽  
Physical Processes ◽  
Small Current ◽  
Short Time ◽  
Non Equilibrium

Since their discovery, steady state arc discharge has been used for fullerenes and nanotubes production. Unfortunately this method intrinsically made it difficult to understand their growth mechanisms since the discharge included many complicated physical processes and the growth happened in the non-equilibrium arc plasma. Processes such as heating of the cathode by cation bombardment, emission of thermal electrons, and heating of the anode by electron bombardment are important in order to follow the mechanism, but it is difficult to study them separately. In the present work, however, it was shown that a pulse-arc discharge with a small current for a short time could simplify the discharge process and provide as-quenched arc products, which should be useful to understand the mechanisms.Short discharges with a small current were performed on the pulse-arc system, which was developed by the authors.

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