Fabrication of a Large-area-patterned Monolayer of Polytetrafluoroethylene Nanoparticles by Surface Charge Induced Colloidal deposition

2014 ◽  
Vol 1663 ◽  
Author(s):  
Chuan Du ◽  
Jiadao Wang ◽  
Darong Chen

ABSTRACTA facile and novel method of fabricating large-area-patterned monolayer of polytetrafluoroethylene(PTFE) nanoparticles was achieved using surface charge induced colloidal deposition. Chemical processes of amination and hydroxylation were used to make the silicon substrates positively and negatively charged, respectively, while the PTFE colloidal nanoparticles were anisotropic and negatively charged. After colloidal deposition, an ordered monolayer with microholes was formed on the amination surface, while an island-like monolayer was achieved on the hydroxylation surface. Both of the two kinds of monolayers were as large as 1.5 square centimeters. It is worth pointing out that these large-area-patterned monolayers were fabricated without any templates and the whole process only took several hours. The formation mechanism of the different structures can be generally attributed to the cooperation and competition of three-body, two-body and particle-wall interactions. It is believed that the interesting patterned monolayer formation mechanism, high production efficiency, good adaptability and quality will make this novel method attractive.

2008 ◽  
Vol 18 (04) ◽  
pp. 889-899 ◽  
Author(s):  
S. R. J. BRUECK

Interferometric lithography offers a facile, inexpensive, large-area fabrication capability for the formation of large areas of nanoscale periodic features. A self-aligned frequency doubling process to a 22-nm half-pitch is demonstrated. Many investigations of nanoscale phenomena require large-area samples, both for scientific investigations and certainly for ultimate large-scale applications. The utility of interferometric lithography is demonstrated to applications in nanophotonics and nanofluidics. For nanophotonics, metamaterial fabrication, negative index metamaterials and plasmonic applications are discussed. Two approaches to the fabrication of nanofluidic structures: etching and oxidation of silicon substrates, and colloidal deposition of silica nanoparticles to form porous walls and roofs followed by calcination to remove the photoresist and sinter the particles. These later structures have evident biomimetic functionality.


2013 ◽  
Vol 380-384 ◽  
pp. 186-190
Author(s):  
Ya Nan Huang ◽  
Da Lu Liu ◽  
Feng Sheng Sun ◽  
Yu Wang ◽  
Ming Xing Gao

When comparing with ship construction within newly-built docks or on tilting slipways, ship constructing on the flat earth method can be said to be a new ship-building technique by which ship is built on a platform and launched with the aid of floating-dock or barge. Some obvious advantages of this technique are such as less investment in basic facilities, low production cost, high production efficiency, wide applicability of ship types, ability to overcome the bottle-neck effect of berths and docks. In this paper, a bulk-carrier being taken as an example, the design of launching processing scheme on the horizontal shipway includes calculation of launching weight and determination of hoisting force during the whole towing period. The whole towing process of hull can be divided into three stages, the first is from the static state to the moment of beginning to move, the second is from the initial position of movement to the front of slipway onto which the hull is predicted to be pulled, and the third is from the front of slipway to the designated position on the floating dock. Subsequently, after the hull being sealed and positioned correctly, the floating dock for launching may be towed to deeper water zone and the hull can be buoyed up on the water surface, and the whole launching process can be completed. From the research, the conclusion is made that the launching technique of this paper is available and feasible. Especially, this paper is the initial application of this method on the 15000t launching ship home and has the epoch-making sense.


2006 ◽  
Vol 3 (3) ◽  
pp. 346-350 ◽  
Author(s):  
Antonio Carlos Caetano de Souza ◽  
José Luz-Silveira ◽  
Maria Isabel Sosa

Steam reforming is the most usual method of hydrogen production due to its high production efficiency and technological maturity. The use of ethanol for this purpose is an interesting option because it is a renewable and environmentally friendly fuel. The objective of this article is to present the physical-chemical, thermodynamic, and exergetic analysis of a steam reformer of ethanol, in order to produce 0.7Nm3∕h of hydrogen as feedstock of a 1kW PEMFC. The global reaction of ethanol is considered. Superheated ethanol reacts with steam at high temperatures producing hydrogen and carbon dioxide, depending strongly on the thermodynamic conditions of reforming, as well as on the technical features of the reformer system and catalysts. The thermodynamic analysis shows the feasibility of this reaction in temperatures about 206°C. Below this temperature, the reaction trends to the reactants. The advance degree increases with temperature and decreases with pressure. Optimal temperatures range between 600 and 700°C. However, when the temperature attains 700°C, the reaction stability occurs, that is, the hydrogen production attains the limit. For temperatures above 700°C, the heat use is very high, involving high costs of production due to the higher volume of fuel or electricity used. The optimal pressure is 1atm., e.g., at atmospheric pressure. The exergetic analysis shows that the lower irreversibility is attained for lower pressures. However, the temperature changes do not affect significantly the irreversibilities. This analysis shows that the best thermodynamic conditions for steam reforming of ethanol are the same conditions suggested in the physical-chemical analysis.


2008 ◽  
Vol 575-578 ◽  
pp. 174-179
Author(s):  
Juan Hua Su ◽  
Feng Zhang Ren ◽  
Lei Wang

This paper analyzes the forming process methods of fin used in CPU chip to emit heat. The whole process is blanking, the first forging forming, the second forging (sizing), and trimming. The chamfer design of CPU fin blank is simulated by finite element analysis. The optimized chamfer 1.6 mm is available. Semi-enclosed cold forging of progressive dies is put forward. The newly designed transfer unit is applied, which unifies the merit of high efficiency of the progressive dies and the high material-using ratio of the project die. Quick disassembly structure is designed and pins are used as quick disassembly pins by means of ball bearing bushing. The unique processing of the shearing scrap structure is adopted when designing the inverted trimming dies. Compared with the traditional die, the mechanization and electrization are realized to increase the production efficiency and get highly precise CPU fin.


Author(s):  
V. Ramamurthy ◽  
G. Sangeetha ◽  
B. Shyla

Background: Horizontal expansion of area under pulses at country level has very little possibilities. This necessitates exploring alternate ways to increase the area and production of pulses. Bt cotton is the major cash crop grown in large area in Southern transition zone of Karnataka on red soils. Bt cotton hybrids are sown at wide row spacing hence provide sufficient space for cultivation of short duration pulses like cowpea and horse gram.Methods: On-farm trials were carried out in medium deep red soils of Basavanagiri village of Mysore district, Karnataka during 2014-15 and 2015-16. There were six treatments consists of Bt cotton with farmers practice (T1), Bt cotton with best management practice (T2), sole cowpea (T3), sole horse gram (T4), Bt cotton intercropped with cowpea (T5) and Bt cotton inter cropped with horse gram (T6). On-farm trials were laid out by using RCBD design in five farmer fields, which served as replications.Result: On-farm investigation indicated that there was no much difference between cotton yield sole crop with BMP and inter cropped cotton yield. However, cotton yield was significantly lower in farmers practice over BMP. Intercropping of cowpea and horse gram with Bt cotton resulted in higher cotton equivalent yield, LER and production efficiency over the sole cotton cropping system. This was due to the wider spacing of the cotton and better resource use efficiency in intercropping system.


2012 ◽  
Vol 22 (39) ◽  
pp. 21154 ◽  
Author(s):  
Jinhe Wang ◽  
Guoquan Min ◽  
Zhitang Song ◽  
Xiuyuan Ni ◽  
Weimin Zhou ◽  
...  

Algorithms ◽  
2019 ◽  
Vol 12 (1) ◽  
pp. 12 ◽  
Author(s):  
Guangluan Xu ◽  
Xiaoke Wang ◽  
Yang Wang ◽  
Daoyu Lin ◽  
Xian Sun ◽  
...  

Link prediction is a task predicting whether there is a link between two nodes in a network. Traditional link prediction methods that assume handcrafted features (such as common neighbors) as the link’s formation mechanism are not universal. Other popular methods tend to learn the link’s representation, but they cannot represent the link fully. In this paper, we propose Edge-Nodes Representation Neural Machine (ENRNM), a novel method which can learn abundant topological features from the network as the link’s representation to promote the formation of the link. The ENRNM learns the link’s formation mechanism by combining the representation of edge and the representations of nodes on the two sides of the edge as link’s full representation. To predict the link’s existence, we train a fully connected neural network which can learn meaningful and abundant patterns. We prove that the features of edge and two nodes have the same importance in link’s formation. Comprehensive experiments are conducted on eight networks, experiment results demonstrate that the method ENRNM not only exceeds plenty of state-of-the-art link prediction methods but also performs very well on diverse networks with different structures and characteristics.


1994 ◽  
Vol 142 ◽  
pp. 877-881
Author(s):  
David Eichler

AbstractMany proficient gamma-ray sources show energy spectra that are consistent with E−2 primary spectra. Such sources include recently identified gamma-ray quasars and some gamma-ray bursts. Assuming thick target conversion, this is consistent with shock acceleration, and the dominance of the gamma rays of the luminosity is also consistent with previous predictions of high production efficiency of fresh cosmic rays in shocks. The spectral cutoffs in the gamma rays may offer clues as to whether the high-energy particles are electrons or protons. Resolution of this matter might have implications for the nature of the sources and for theory of shock accelerated electrons.Subject headings: acceleration of particles — gamma rays: bursts — shock waves


2014 ◽  
Vol 621 ◽  
pp. 158-164
Author(s):  
Hao Yan Wang ◽  
Zhe He Yao ◽  
De Qing Mei

Micro/meso forming, as an emerging manufacturing process for miniature metallic workpieces, has attracted great attention since the 1990s due to its high production efficiency, low material waste and high precision. Due to the so-called size effects in the scaling down, many traditional theories in metal forming cannot be simply applied to the micro/meso forming. In this study, the micro/meso upsetting experiments of Brass H62 were conducted at various temperatures. The stress−strain curves in the experiments were measured and compared. The effects of the temperature and the sample size on the flow stress were discussed. It is found that the flow stress of the material decreased with the decrease of the sample size at room temperature. However, the flow stress of the material may increase with the decrease of the sample size at elevated temperatures. The results indicate that the size effects in the micro/meso forming are significantly affected by the processing temperature.


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