Fundamental Study on Diamond Spherical Shell Film for Polishing of Concave Spherical Surface

2008 ◽  
Vol 375-376 ◽  
pp. 380-384
Author(s):  
Duo Sheng Li ◽  
Dun Wen Zuo ◽  
Rong Fa Chen ◽  
Yu Li Sun ◽  
Bing Kun Xiang ◽  
...  

In this paper, a new polishing technique was proposed to polish concave spherical surface by diamond spherical shell deposited by DC-Plasma Jet CVD(chemical vapor deposition), and preparation was studied from both experiment and theory. The deposited films were investigated by some techniques including: scanning electron microscopy (SEM), atom force microscopy (AFM), Raman spectroscopy, and roughness-profile-meter, which were used to analyze surface phase, microstructure, internal quality and surface roughness. The results show that the deposited diamond spherical shell film has some remarkable properties, such as high surface density, high hardness. Compared to traditional polishing techniques, it will have some potential advantages as convenient, flexible, efficient and precious. To adjust some important parameters as methane concentration, depositing time, and it can deposit the different size grain diamond spherical shell films, which are used to polish different precision degree concave spherical surfaces. Meantime, to change curvature of diamond spherical shell, it can adapt to polish various curvature radius concave spherical surfaces.

Micromachines ◽  
2021 ◽  
Vol 12 (5) ◽  
pp. 512
Author(s):  
Chi-Hsien Huang ◽  
Hong-Cing Wu ◽  
Bo-Feng Chen ◽  
Yen-Cheng Li

Polycrystalline graphene grown by chemical vapor deposition (CVD) is characterized by line defects and disruptions at the grain boundaries and nucleation sites. This adversely affects the stretchability and conductivity of graphene, which limits its applications in the field of flexible, stretchable, and transparent electrodes. We demonstrate a composite electrode comprised of a graphene/silver nanowires (AgNWs)/graphene sandwich structure on a polydimethylsiloxane substrate to overcome this limitation. The sandwich structure exhibits high transparency (>90%) and excellent conductivity improvement of the graphene layers. The use of AgNWs significantly suppresses the conductivity loss resulting from stretching. The mechanism of the suppression of the conductivity loss was investigated using scanning electron microscopy, atomic force microscopy, and lateral force microscopy. The results suggest that the high surface friction of the sandwich structure causes a sliding effect between the graphene layers would produce low crack or hole formation to maintain the conductivity. In addition to acting as conductive layers, the top and bottom graphene layers can also protect the AgNWs from oxidation, thereby enabling maintenance of the electrical performance of the electrodes over a prolonged period. We also confirmed the applicability of the sandwich structure electrode to the human body, such as on the wrist, finger, and elbow.


2020 ◽  
Vol 15 (S359) ◽  
pp. 192-194
Author(s):  
Elismar Lösch ◽  
Daniel Ruschel-Dutra

AbstractGalaxy mergers are known to drive an inflow of gas towards galactic centers, potentia- lly leading to both star formation and nuclear activity. In this work we aim to study how a major merger event in the ARP 245 system is linked with the triggering of an active galactic nucleus (AGN) in the NGC galaxy 2992. We employed three galaxy collision numerical simulations and calculated the inflow of gas through four different concentric spherical surfaces around the galactic centers, estimating an upper limit for the luminosity of an AGN being fed the amount of gas crossing the innermost spherical surface. We found that these simulations predict reasonable gas inflow rates when compared with the observed AGN luminosity in NGC 2992.


2014 ◽  
Vol 687-691 ◽  
pp. 3-6
Author(s):  
Da Ming Wang ◽  
Ming Zhe Li ◽  
Zhong Yi Cai

3D rolling is a novel technology for three-dimensional surface parts. In this process, by controlling the gap between the upper and lower forming rolls, the sheet metal is non-uniformly thinned in thickness direction, and the longitudinal elongation of the sheet metal is different along the transverse direction, which makes the sheet metal generate three-dimensional deformation. In this paper, the transition zones of spherical surface parts in 3D rolling process are investigated. Spherical surface parts with the same widths but different lengths are simulated in condition of the same roll gap, and their experimental results are presented. The forming precision of forming parts and the causes of transition zones in the head and tail regions are analyzed through simulated results. The simulated and experimental results show that the lengths of transition zones of spherical surfaces in the head and tail regions are fixed values in condition of the same sheet width and roll gap.


1995 ◽  
Vol 403 ◽  
Author(s):  
G. Bai ◽  
S. Wittenbrock ◽  
V. Ochoa ◽  
R. Villasol ◽  
C. Chiang ◽  
...  

AbstractCu has two advantages over Al for sub-quarter micron interconnect application: (1) higher conductivity and (2) improved electromigration reliability. However, Cu diffuses quickly in SiO2and Si, and must be encapsulated. Polycrystalline films of Physical Vapor Deposition (PVD) Ta, W, Mo, TiN, and Metal-Organo Chemical Vapor Deposition (MOCVD) TiN and Ti-Si-N have been evaluated as Cu diffusion barriers using electrically biased-thermal-stressing tests. Barrier effectiveness of these thin films were correlated with their physical properties from Atomic Force Microscopy (AFM), Transmission Electron Microscopy (TEM), Secondary Electron Microscopy (SEM), and Auger Electron Spectroscopy (AES) analysis. The barrier failure is dominated by “micro-defects” in the barrier film that serve as easy pathways for Cu diffusion. An ideal barrier system should be free of such micro-defects (e.g., amorphous Ti-Si-N and annealed Ta). The median-time-to-failure (MTTF) of a Ta barrier (30 nm) has been measured at different bias electrical fields and stressing temperatures, and the extrapolated MTTF of such a barrier is > 100 year at an operating condition of 200C and 0.1 MV/cm.


2021 ◽  
Vol 316 ◽  
pp. 794-802
Author(s):  
Andrey E. Balanovsky ◽  
Van Trieu Nguyen

The Purpose of paper is to conduct studies to assess the possibility of increasing the hardness of the surface layer of steel St3 grade by plasma heating of the applied surface coating containing powder alloy PR-N80X13S2R. Mixtures of pasta were divided into 2 groups: for furnace chemical-thermal treatment and plasma surface melting. The study of the microstructure showed a difference in the depth of the saturated layer, depending on the processing method, during chemical-thermal treatment-1 mm, plasma fusion - 2 mm. The results of measuring the surface micro-hardness showed that, the obtained coating from a mixture of PR-N80X13S2R + Cr2O3 + NH4Cl has a uniform high surface hardness (31-64 HRC), from a mixture of only PR-N80X13S2R - the surface hardness varies in a wide range (15-60 HRC). The study of the microhardness of the cross section of the surface layer showed that, the diffusion region: from a mixture of powder PR-N80X13S2R + Cr2O3 + NH4Cl has uniform hardness (450-490 HV); from a mixture of PR-N80X13S2R - hardness increases in the depth of the molten region (from 300 to 600 HV), and sharply decreases in the heat affected zone (210-170 HV). The use of PR-N80X13S2R alloy powder as the main component in the composition of the paste deposited on the St3 surface during plasma treatment leads to the formation of a doped surface layer with high hardness.


Cerâmica ◽  
2002 ◽  
Vol 48 (305) ◽  
pp. 38-42 ◽  
Author(s):  
M. I. B. Bernardi ◽  
E. J. H. Lee ◽  
P. N. Lisboa-Filho ◽  
E. R. Leite ◽  
E. Longo ◽  
...  

The synthesis of TiO2 thin films was carried out by the Organometallic Chemical Vapor Deposition (MOCVD) method. The influence of deposition parameters used during growth on the final structural characteristics was studied. A combination of the following experimental parameters was studied: temperature of the organometallic bath, deposition time, and temperature and substrate type. The high influence of those parameters on the final thin film microstructure was analyzed by scanning electron microscopy with electron dispersive X-ray spectroscopy, atomic force microscopy and X-ray diffraction.


2012 ◽  
Vol 2012 ◽  
pp. 1-5 ◽  
Author(s):  
S. Ktifa ◽  
M. Ghrib ◽  
F. Saadallah ◽  
H. Ezzaouia ◽  
N. Yacoubi

We have studied the optical properties of nanocrystalline silicon (nc-Si) film deposited by plasma enhancement chemical vapor deposition (PECVD) on porous aluminum structure using, respectively, the Photothermal Deflection Spectroscopy (PDS) and Photoluminescence (PL). The aim of this work is to investigate the influence of anodisation current on the optical properties of the porous aluminum silicon layers (PASL). The morphology characterization studied by atomic force microscopy (AFM) technique has shown that the grain size of (nc-Si) increases with the anodisation current. However, a band gap shift of the energy gap was observed.


2002 ◽  
Vol 751 ◽  
Author(s):  
T. Horiuchi ◽  
H. Ochi ◽  
K. Kaisei ◽  
K. Ishida ◽  
K. Matsushige

ABSTRACTSurface lattice displacements of titanium dioxide (TiO2: rutile) during ultra-violet (UV) light irradiation have been investigated using a total reflection x-ray diffraction, which provides a high signal to noise ratio (S/N) and superior in-plane surface diffraction. Under the environments in vapors of H2O, CH3OH, C2H5OH and C3H6OH, the photo-catalytic activities of TiO2 (110), (100) and (001) surfaces subject to UV irradiation have been measured. It is found that the diffraction peaks and their full width half maxima (FWHMs) show some peculiarities with respect to the photo-catalytic activities in both surface lattices and adsorbed molecules in vapors. Furthermore, Kelvin force microscopy (KFM) has showed that there exists a very high surface potential, probably due to surface atom displacements induced by UV irradiation. With regard to the origin of the photo-catalytic activities, the induced surface potentials are discussed.


2009 ◽  
Vol 1203 ◽  
Author(s):  
R. Vispute ◽  
Andrew Seiser ◽  
Geun Lee ◽  
Jaurette Dozier ◽  
Jeremy Feldman ◽  
...  

AbstractA compact and efficient hot filament chemical vapor deposition system has been designed for growing electronic-grade diamond and related materials. We report here the effect of substrate rotation on quality and uniformity of HFCVD diamond films on 2” wafers, using two to three filaments with power ranging from 500 to 600 Watt. Diamond films have been characterized using x-ray diffraction, Raman Spectroscopy, scanning electron microscopy and atomic force microscopy. Our results indicate that substrate rotation not only yields uniform films across the wafer, but crystallites grow larger than without sample rotation. Well-faceted microcrystals are observed for wafers rotated at 10 rpm. We also find that the Raman spectrum taken from various locations indicate no compositional variation in the diamond film and no significant Raman shift associated with intrinsic stresses. Results are discussed in the context of growth uniformity of diamond film to improve deposition efficiency for wafer-based electronic applications.


Micromachines ◽  
2021 ◽  
Vol 12 (12) ◽  
pp. 1460
Author(s):  
Myung Gi Ji ◽  
Mohammed Bazroun ◽  
In Ho Cho ◽  
W. Dennis Slafer ◽  
Rana Biswas ◽  
...  

Replica molding-based triboelectrification has emerged as a new and facile technique to generate nanopatterned tribocharge on elastomer surfaces. The “mechano-triboelectric charging model” has been developed to explain the mechanism of the charge formation and patterning process. However, this model has not been validated to cover the full variety of nanotexture shapes. Moreover, the experimental estimation of the tribocharge’s surface density is still challenging due to the thick and insulating nature of the elastomeric substrate. In this work, we perform experiments in combination with numerical analysis to complete the mechano-triboelectrification charging model. By utilizing Kelvin probe force microscopy (KPFM) and finite element analysis, we reveal that the mechano-triboelectric charging model works for replica molding of both recessed and protruding nanotextures. In addition, by combining KPFM with numerical electrostatic modeling, we improve the accuracy of the surface charge density estimation and cross-calibrate the result against that of electrostatic force microscopy. Overall, the regions which underwent strong interfacial friction during the replica molding exhibited high surface potential and charge density, while those suffering from weak interfacial friction exhibited low values on both. These multi-physical approaches provide useful and important tools for comprehensive analysis of triboelectrification and generation of nanopatterned tribocharge. The results will widen our fundamental understanding of nanoscale triboelectricity and advance the nanopatterned charge generation process for future applications.


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