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Various Configurations (various + configuration)
Selected AbstractsMean-Square End-to-End Distance and Characteristic Ratio of Polyvinylene (Polyacetylene) Chains of Various ConfigurationsMACROMOLECULAR CHEMISTRY AND PHYSICS, Issue 2 2006í Vohlídal Abstract Summary: Closed-form analytical expressions are derived for the mean-square end-to-end distance of unperturbed polyvinylene chains of various configurational structure with freely rotating main-chain single bonds. In particular, expressions are derived for (i) stereoregular chains: all- trans, all- cis and cis - trans alternating; (ii) atactic cis - trans chains with a Bernoullian distribution of cis and trans units along the chain and various content of trans units, (iii) regularly segmented cis - trans chains [,cisy,transy,]n and (iv) diblock chains cisx,transy. The conformation factor is determined for several atactic polyvinylenes for which the unperturbed dimensions are available in the literature. [source] Influence of the intracavity second harmonic generation on the mode competition in a double-mode diode-pumped Nd:YAG laserLASER PHYSICS LETTERS, Issue 7 2005V. M. Yermachenko Abstract The influence of intracavity second harmonic generation on the mode competition in a double-mode diode-pumped Nd:YAG laser is studied theoretically and experimentally. Various configurations of the optical cavity with II-type phasematching frequency-doubling crystals are considered. The conditions of steady-state lasing and of lasing with a small level of amplitude pulsation in the output laser beam are determined. (© 2005 by Astro, Ltd. Published exclusively by WILEY-VCH Verlag GmbH & Co. KGaA) [source] Reconfigurable multiwavelength erbium-doped fiber laser using two multimode fiber Bragg gratingsMICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 7 2007Jin-Hua Yan Abstract A reconfigurable multiwavelength erbium-doped fiber laser, using two multimode fiber Bragg gratings (MFBGs), is presented. Two MFBGs in L-band are cascaded to form two overlapping resonant cavities. Various configurations of four-, three-, or two-wavelength lasing are demonstrated experimentally by appropriately controlling the two polarization controllers inside the cavities. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 1509,1511, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22493 [source] Enhanced luminescence and two-photon absorption of silver nano-clustersPHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue S1 2009A. V. Aiboushev Abstract Luminescence of silver nanoparticles photo-deposited on titan dioxide nanoparticles of mesoporous film is studied. Luminescence was registered under the two-photon excitation by femto-second laser pulses of Ti:sapphire laser. It was observed that Ag/ TiO2 mesoporous films have high concentration of bright luminescence spots which reveal stability to degradation under long illumination. Various configurations of silver nanoparticles are analyzed to explain the physics of bright luminescence spots ("hot spots"). Luminescence intensity reveals "hot spots" dependence on the polarization of excitation laser pulse. Properties of Ag/TiO2 system can be useful for single molecule spectroscopy and visualization of biological objects. Aapplication of Ag/ TiO2 mesoporous films for Raman scattering spectroscopy de-menstruated for the case of Rhodamine B. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Preliminary evaluation of electroencephalographic entrainment using thalamocortical modellingEXPERT SYSTEMS, Issue 4 2009Dean Cvetkovic Abstract: The concept of linked oscillators in biological control systems has long been established. Frequency entrainment is a predominant explanation behind many biological rhythms. In this paper a preliminary examination of electroencephalographic entrainment is made to survey the possibility and methods of achieving signal entrainment at the highest level of neurological organization and function. A model of the thalamocortical system is employed to generate simulated electroencephalographic signals and is tested in various configurations in the search for entrainment under very simple conditions. Additionally, an analysis of the coupled Van der Pol model of the circadian rhythm controller is performed to identify the possibility of affecting that system with a drastically different coupling input signal. We were able to conclude that overall signal shape can have a significant impact on the entrainment characteristics of the system. Due to the nature of the underlying mathematical structure of the model, by examining the circadian rhythm controller, we found that it is unsuitable for entrainment to an incident entraining signal of much higher frequency. [source] Effect of leading edge cut on the aerodynamics of ram-air parachutesINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS, Issue 1 2005R. Balaji Abstract The effect of the configuration of leading edge cut on the aerodynamic performance of ram-air parachutes is studied via two-dimensional flow simulations. The incompressible Reynolds-averaged Navier,Stokes equations, in primitive variables, are solved using a stabilized finite-element formulation. The Baldwin,Lomax model is employed for turbulence closure. Flow past an LS(1) 0417 airfoil is investigated for various configurations of the leading edge cut and results are compared with those from a Clark-Y airfoil section. It is found that the configuration of the leading edge cut affects the lift-to-drag ratio (L/D) of the parachute very significantly. The L/D value has strong implications on the flight performance of the parachute. One particular configuration results in a L/D value that is in excess of 25 at 7.5° angle of attack. Results are presented for other angles of attack for this configuration. Copyright © 2004 John Wiley & Sons, Ltd. [source] End-to-end response time with fixed priority scheduling: trajectory approach versus holistic approachINTERNATIONAL JOURNAL OF COMMUNICATION SYSTEMS, Issue 1 2005Steven Martin Abstract In this paper, we are interested in providing deterministic end-to-end guarantees to real-time flows in a distributed system. We focus on the end-to-end response time, quality of service (QoS) parameter of the utmost importance for such flows. We assume that each node uses a Fixed Priority scheduling. We determine a bound on the end-to-end response time of any real-time flow with a worst case analysis using the trajectory approach. We establish new results that we compare with those provided by the classical holistic approach for flows visiting the same sequence of nodes. These results show that the trajectory approach is less pessimistic than the holistic one. Moreover, the bound provided by our worst-case analysis is reached in various configurations, as shown in the examples presented. Copyright © 2004 John Wiley & Sons, Ltd. [source] Consistent treatment of inter- and intramolecular polarization in molecular mechanics calculationsJOURNAL OF COMPUTATIONAL CHEMISTRY, Issue 16 2002Pengyu Ren Abstract A protocol is described for the treatment of molecular polarization in force field calculations. The resulting model is consistent in that both inter- and intramolecular polarization are handled within a single scheme. An analytical formula for removing intramolecular polarization from a set of atomic multipoles for an arbitrary static structure or conformation is given. With the help of the intramolecular polarization, these permanent atomic multipoles can then be applied in modeling alternative conformations of a molecule. Equipped with this simple technique, one can derive transferable electrostatic parameters for peptides and proteins using flexible model compounds such as dipeptides. The proposed procedure is tested for its ability to describe the electrostatic potential around various configurations of the N -methylacetamide dimer. The effect of different intramolecular polarization schemes on the accuracy of a force field model of the electrostatic potential of alanine dipeptide is investigated. A group-based scheme for including direct intramolecular polarization is shown to be most successful in accounting for the conformational dependence of electrostatic potentials. © 2002 Wiley Periodicals, Inc. J Comput Chem 23: 1497,1506, 2002 [source] The design of single particle laser mass spectrometers,MASS SPECTROMETRY REVIEWS, Issue 2 2007Daniel M. MurphyArticle first published online: 16 OCT 200 Abstract This review explores some of the design choices made with single particle mass spectrometers. Different instruments have used various configurations of inlets, particle sizing techniques, ionization lasers, mass spectrometers, and other components. Systematic bias against non-spherical particles probably exceeds a factor of 2 for all instruments. An ionization laser tradeoff is the relatively poor beam quality and reliability of an excimer laser versus the longer wavelengths and slower response time of an Nd-YAG laser. Single particle instruments can make special demands on the speed and dynamic range of the mass spectrometers. This review explains some of the choices made for instruments that were developed for different types of measurements in the atmosphere. Some practical design notes are also given from the author's experience with each section of the instrument. Published 2006 Wiley Periodicals, Inc., Mass Spec Rev 26:150,165, 2007 [source] The thoracodorsal vascular tree-based combined fascial flapsMICROSURGERY, Issue 2 2009Meisei Takeishi M.D. In this study, combined fascial flaps pedicled on the thoracodorsal artery and vein were raised and used for thin coverage of dorsal surfaces of the fingers and the dorsum of hand and foot with favorable results. The combined fascial flaps consist of the serratus anterior fascia and the axillary fascia at the entrance of the latissimus dorsi. These flaps were used for reconstruction of the hand, fingers, or foot in nine patients. Reconstruction was performed for burn or burn scar contracture, after resection of malignant tumors, posttraumatic skin defects, and chronic regional pain syndrome. The sites of reconstruction were dorsal surfaces of fingers, dorsum of hand, wrist and palm, forearm, lower leg, and foot. The flaps were used in various configurations including two independent fascial flaps, two-lobed fascial flap with separate feeding vessels, and composite fascial and thoracodorsal artery perforator flap. The fascial and skin flaps survived in all nine patients, with favorable results both functionally and esthetically. Good coverage of soft tissue defects and good recovery of range of motion in resurfaced joints were achieved. There were no complications. The scars at the sites of harvest were not noticeable. The advantage of this method is that not only a single flap but flaps of a variety of configurations can be harvested for different purposes. The thoracodorsal vascular tree-based combined fascial flaps are useful for the reconstruction of soft tissue defects in the extremities. © 2008 Wiley-Liss, Inc. Microsurgery, 2009. [source] Experimental optimization of the 2nd loop configuration for feedforward amplifiers in terms of their efficiency and linearityMICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 3 2006Sung-Chan Jung Abstract In this paper, we report the results of the experimental optimization of the 2nd -loop configuration for feedforward amplifiers in terms of their efficiency and linearity. We consider two parameters in the 2nd -loop of a feedforward amplifier: (i) the size ratio between the main and error amplifiers and (ii) the coupling factor of the error signal coupler. Experiments are performed using a multicarrier down-link WCDMA signal under various configurations. The measured data, which are normalized with respect to the overall power capacity of the main and error amplifiers, show that, among the different 2nd -loop configurations, the best compromised efficiency (13.4%) at a given adjacent channel leakage ratio (ACLR) level (,50 dBc) is observed for a size ratio of around 3.0 and a coupling factor of around 7.2 dB. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 617,621, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21425 [source] Remarks on studies for direct production of phenol in conventional and membrane reactorsASIA-PACIFIC JOURNAL OF CHEMICAL ENGINEERING, Issue 1 2010Raffaele Molinari Abstract The great interest in the oxidation reaction of benzene to phenol is linked to some disadvantages of the cumene process, such as environmental impact, production of an explosive intermediate, a multi-step process (which involves (1) difficulty to achieve high phenol yield, in relation to the benzene used and (2) high capital investment), and a high acetone production as a co-product which results in an over supply in the market. In this paper, we discuss various studies concerning a new approach based on a one-step and acetone-free method for phenol production. Particular attention is devoted to phenol production processes using various configurations of membrane reactors (MRs) and a photocatalytic membrane reactor (PMR). In particular, the biphasic MR allowed to achieving high selectivity values (97,98%). The described studies have been classified according to oxidant type such as N2O, O2, and H2O2. Each of them shows that direct oxidation of benzene to phenol is a difficult task and further efforts are needed to search and replace the three step traditional process of converting benzene into phenol with a process of direct oxidation. Copyright © 2009 Curtin University of Technology and John Wiley & Sons, Ltd. [source] Membrane bioreactors: overview of the effects of module geometry on mixing energyASIA-PACIFIC JOURNAL OF CHEMICAL ENGINEERING, Issue 3 2009Yuan Wang Abstract Membranes used in municipal membrane bioreactor (MBR) plants can be configured as flat sheet (FS) membranes or hollow fibre (HF) membranes. The HFs can be mounted either horizontally or vertically. The membranes can be immersed in their own vessel or within the aerobic vessel. These various configurations combine to give a unique reactor design. Current methods of design assume the mixing characteristics (e.g. each reactor vessel is completely mixed); hence the energy necessary to achieve complete mixing cannot be optimised. This paper presents an overview of mixing studies undertaken by the authors' research group on pilot- and full-scale MBRs through residence time distribution (RTD) analysis and computational fluid dynamics (CFD) modelling. The drawbacks of current technique for the sizing of MBRs (e.g. compartmental modelling) are highlighted. The use of CFD as a design tool to evaluate the mixing and energy of MBRs with different configurations (e.g. HF vs FS, inside submerged vs outside submerged) is presented. The MBR CFD model was validated using field-measured RTD data and compared with compartmental model. Results from mixing studies suggest that HF membranes are more energy efficient in terms of creating completely mixed conditions than the FS membranes. Copyright © 2009 Curtin University of Technology and John Wiley & Sons, Ltd. [source] | ||||||||||||||||