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Carbon nanoparticles (CNPs) were synthesized by the plasma-based ion implantation method, and structural variations and the synthesis mechanism of CNPs were investigated. CNPs were grown by implanting carbon ions from methane gas into thin silver films. To obtain pure CNPs from the silver matrix, the silver films were evaporated by a thermal process under high vacuum. XPS depth analysis revealed that initially silver atoms were preferably sputtered during implantation, then CNPs gradually started to appear on the silver and carbon atoms concentrated near the surface. Stacked carbons on the surface may prevent silver films from being sputtered and carbon ions from penetrating into the silver matrix. The CNPs grew up to 20 nm, but their size did not increase after the implantation for 2 h. Instead, a membrane cluster among the CNPs was observed after the implantation for 3 h. Thermal process at 750 °C for removing silver to obtain only CNPs did not affect CNP growth. Raman spectra indicated that spherical CNPs consist of graphitic structure and long-time implantation yielded amorphous membranes as well as the CNPs. Copyright © 2014 John Wiley & Sons, Ltd.

This letter presents a design of a novel ultrawideband (UWB) circular fractal monopole antenna with a six-petaled flower pattern. The coplanar-waveguide-fed technique and fractal concept have been used to achieve UWB characteristics. The size of the proposed antenna is 43 × 51 mm2 with a flower-shaped circular patch radius of 15 mm. The proposed antenna exhibits UWB characteristics from 2.46 to 13.46 GHz, which corresponds to a fractional bandwidth of 138%. The measured radiation pattern of the proposed antenna is nearly omnidirectional. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1792–1795, 2013

In this letter, a printed planar inverted-F antenna is proposed for a quad-band operation.The proposed quasi-rectangular loop configuration yields the first and second resonant frequencies at 900 and 1800 MHz, respectively. The additional shorted strip on the bottom can expand the bandwidth at the upper band. The proposed antenna area is 8 × 38 mm2 and the ground size is 72 × 40 mm2. The measured impedance bandwidth, determined by 3:1 VSWR, has fully covered the GSM900 (880–960 MHz), DCS (1710–1880 MHz), PCS (1850–1990 MHz), and UMTS (1920–2170 MHz) frequency bands. The measured gain is higher than −1 dBi over the entire quad-band. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:2337–2341, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27099

Self-assembled monolayers (SAMs) of 1H,1H,2H,2H-perfluorodecyltrichlorosilane (FDTS) were prepared on hydrogen-free diamond-like carbon (DLC) films by immersing the DLC substrates into dilute solutions of FDTS in hydrofluoroether. The FDTS-adsorbed DLC surfaces were observed using a tapping mode atomic force microscopy (AFM) with respect to the immersion time to investigate the monolayer formation process. The measurements of the water contact angles, X-ray photoelectron spectroscopy (XPS) and the surface roughness were also conducted. The DLC films were deposited on silicon plates with an electron cyclotron resonance(ECR)-type ion beam sputter using graphite as a sputter target. Initially, FDTS molecules form a liquid-like disordered mass of molecules on the DLC surface, and then begin to form densely packed FDTS islands with the height of a monolayer. The FDTS monolayer islands grow laterally with the immersion time. After immersion for several hours, the agglomeration of FDTS molecules to a height of 3-5 nm is observed on the DLC surfaces. This is due to the presence of a large number of active sites on the hydrogen-free DLC surface, preventing the surface diffusion of FDTS molecules. Also, the inhomogeneity of the DLC surface due to the adsorption of a large number of oxygen atoms from the air after DLC deposition is one of the reasons for the FDTS agglomeration.

In the present study, the effects of silicon oxide layer of Si-DLC coatings on the tribological properties were investigated. The Si-DLC coatings were deposited on Si substrates using a bi-polar type plasma-based ion implantation and deposition technique (bi-polar type PBII&D), and the surface of the Si-DLC coating was treated by oxygen plasma for 180 seconds. The friction coefficient of the Si-DLC coatings is effectively reduced due to the treatment of oxygen plasma whereas the wear depth of oxidized Si-DLC coatings increases due to the wear of soft oxide layer. A transferred layer composed of silicon oxide and graphitic carbon was observed on the counter steel ball surface, and the amount of the transferred layer increases by the treatment of oxygen plasma. The transferred layer prevents contact between the steel and DLC surfaces when sliding, resulting in a low friction coefficient. It seems that the silicon oxide plays a roll to bind the lubricative graphitized carbon debris on the steel ball surface. The treatment of the oxygen plasma on the top surface of the Si-DLC coatings can effectively reduce the friction coefficient without hardness reduction in the entire Si-DLC coatings. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

Diamond-like carbon (DLC) films are deposited on Si substrates using acetylene (C 2 H 2 ), toluene (C 7 H 8 ) abd their mixed gas, and the microstructures are examined by micro-Raman spectroscopy. Rutherford backscattering spectrometry (RBS) and elastic recoil detection (ERD) analysis as a function of negatively pulsed voltages (V n ). It is found that the formation of graphite-like structure (aromatic ring clustering) is enhanced with increasing V n . In addition, the density of the films is increased up to approximately 2.0 g/cm 3 and the H concentration is decreased with increasing V n . The use of C 2 H 2 has much effect on the formation of graphite-like structure and the reduction of H concentration in the films at high V n as compared with others. The deposition rate of the films is increased of the films is increased with increasing V n . Relatively high deposition rate is obtained when using C 7 H 8 . In the case of the mixed gas, the deposition rate is found to be close to that of C 7 H 8 . These results suggest that C 7 H 8 is dominant to the deposition process when using the mixture of C 2 H 2 +C 7 H 8 .

In the present study, the effect of deposition pressure on the deposition rate and various properties of diamond-like carbon (DLC) coatings were investigated. The DLC coatings were deposited on Si substrates using a bipolar-type plasma-based ion implantation and deposition plasma based ion implantation and deposition (PBIID) technique. The toluene was used as a source gas and the deposition pressure ranged from 0.03 to 2.0 Pa. The deposition rate of the DLC coatings increases about 12 times as the deposition pressure is changed from 0.03 to 2.0 Pa. Also, the surface roughness increases with increasing deposition pressure due to high deposition rate. The hardness and elastic modulus decrease when the deposition pressure exceed 0.7 Pa due to the remarkable growth of graphitic islands. The corrosion protection performance of the DLC coating deposited at 2.0 Pa is superior to that of the DLC coating deposited at 0.2 Pa for the same deposition time of 1 h. The high deposition pressure for the DLC coating is effective in improvement of corrosion protection properties.

The research looks at the structure of the Internet backbone and air transport networks between 82 cities in 2002, using Internet backbone bandwidth and air passenger traffic data. Centrality measures on individual city's hierarchy in the Internet and in the air traffic networks were significantly correlated, with London in the most dominant position in both networks. A quadratic assignment procedure (QAP) showed a structural equivalence between two systems. The division and membership of the clusters in both networks also showed similarity; both networks had a strongly cohesive North American-European cluster with the London-New York dyad as the strongest linkage in the global flow of information and people. These findings suggest that current trends in Internet infrastructure concentration reproduce and maintain global inequality and hierarchy among world cities.

In this report, we describe the bonding characteristics of a model lubricant, perfluoro-1-decanol (P1D), having a hydroxyl end group, toward N and Si incorporated amorphous carbon surfaces. The P1D is deposited on the carbon surfaces using vacuum vapor deposition, and the P1D bonding toward the carbon surfaces is compared to that deposited by immersion, a traditional deposition method. The P1D molecules are strongly bonded to the carbon surfaces by the vacuum vapor deposition, whereas the bondings are minimal in the case of immersion. The N and Si incorporation enhances the bonding of P1D toward the carbon surfaces. This is due to the change in the surface structure of the hydrogen-terminated carbon surfaces by N and Si incorporation into the carbon network, which increases the adsorption sites on the carbon surfaces.

Summary In market-based cloud environments, both resource consumers and providers are self-interested; additionally, they can come and leave the environment freely. Therefore, the environment is competitive and uncertain. Because of the competition, participants may cheat in making deals, and this represents that the environment is insecure to resource providers who intend to earn profits through renting their resources to the tasks of resource consumers. Against this, in this paper, intelligent agents are designed to strategically quote for the tasks that they are interested in, on behalf of resource providers. Agents could quote according to the messages it obtained and the information learnt and predicted from the messages, to minimize the influence of insecure factors, such as cheating, competition, and dynamism. The experimental evaluation shows that the proposed method outperforms both a well-known multiresource negotiation-based task allocation method and a max-sum belief propagation–based method.

A novel G-shaped antenna with a coplanar waveguide (CPW) feed is proposed. The advantages of a CPW feed are to simplify the antenna structure with a single metallic level and reduce the antenna size. Operating resonant modes of the proposed antenna are related to the length of two folded monopoles. A face-to-face structure of two folded monopoles is yielded to broaden the lower and upper bands. The measured return loss, radiation patterns, and gains are presented. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 2310–2311, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21924