bluuebunny/crossref_metadata_2025_split huggingface dataset:
Tunneling through molecular wires: a comparison of the Franz two‐band model with exact results
Authors: Malysheva L. , Onipko A. 
Published: September 2007

AbstractThis report concerns finding the tunneling exponential factor exp [–2κ (E) d ], on the basis of electronic band structure of organic oligomers, which are d ‐long molecular wires. It is shown that energy dependence κ (E) given by the Franz two‐band model agrees remarkably well with exact model calculations, provided that the quadratic dispersion parameter is calculated from the real (non‐parabolic) band structure of organic oligomers. For narrow and moderate band gaps (with respect to the band width), the approximate dependence is practically indistinguishable from that which is obtained from these exact calculations. The divergence (particularly, in the mid of the band gap) becomes appreciable and increases with an increase of the band‐gap/band‐width ratio. The apparent effective mass (as it is estimated from κ (E) measured at the Fermi energy E = EF) is defined in terms of the inherent parameters of the wire. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The fulleride polymer Mg5C60
Authors: Quintavalle D. , Simon F. , Jánossy A. , Borondics F. , Baserga A. , Kamarás K. , Pekker S. 
Published: September 2007

AbstractWe synthesized a series of Mgx C60 samples with nominal composition of x between 1 and 6 via solid state reaction between C60 and Mg powder. For x = 5 a two dimensional structure was found. The polymer phase is unusually stable up to high temperatures, it remains unchanged at 823 K for 20 minutes as confirmed by ESR. The mid‐infrared absorption spectrum suggests that the polymer sheets contain single bonded fulleride ions. Both the spin susceptibility and microwave conductivity measurements show that Mg5C60 is metallic for T > 200 K. The transition from metallic to insulating states around 200 K may be attributed to Anderson localization. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
High‐yield synthesis of single‐walled carbon nanotubes with a pulsed arc‐discharge technique
Authors: Roch Aljoscha , Jost Oliver , Schultrich Bernd , Beyer Eckhard 
Published: September 2007

AbstractThis contribution deals with the synthesis of Single‐Walled Carbon Canotubes (SWCNT) with a novel pulsed arc‐discharge technique. Pulsed arc‐discharge is a very interesting technique because it is similar to the well‐known laser evaporation technique for the synthesis of SWCNT and should allow a scale‐up to reach a SWCNT volume production. We performed a number of experiments to find optimal conditions for the arc‐based SWCNT synthesis. The obtained data have been compared with known results from laser evaporation synthesis of SWCNT. The results indicate that it is possible to get specifically optimized synthesis conditions for the arc‐discharge method that are very similar to that of the laser evaporation synthesis. Both methods allow to get similar nanotube qualities (high yield, narrow diameter distribution). We discuss similarities in the formation mechanisms between both methods. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Electrical conductivity recovery in carbon nanotube–polymer composites after transient shear
Authors: Alig I. , Skipa T. , Engel M. , Lellinger D. , Pegel S. , Pötschke P. 
Published: September 2007

AbstractInvestigations on electric conductivity have been performed on polycarbonate (PC) containing 0.6 vol% of multi‐walled carbon nanotubes (MWNT) in a rheometer, where the plates act as capacitor plates for dielectric spectroscopy. The time dependent recovery of the DC‐conductivity was recorded in the rest time after a transient shear deformation. The DC‐conductivity shows a tremendous increase with the time after shearing. This conductivity recovery is explained by the reorganization of the conducting MWNT‐network, which was destroyed by the shear. The reformation kinetics of MWNT‐clusters is considered as a cooperative cluster‐cluster aggregation coupled to electrical percolation of conductive MWNT. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Nanocarbons: efficient synthesis using natural lava as supported catalyst
Authors: Su D. S. , Rinaldi A. , Frandsen W. , Weinberg G. 
Published: September 2007

AbstractLow‐cost mass production of CNTs becomes prerequisite for their applications in chemistry and catalysis in which the availability of large amounts of material with well‐defined surface, chemical and mechanical properties is required. Natural occurring iron oxides in volcanic lavas are used as catalysts for CNT synthesis in the well‐established CVD (chemical vapor deposition) process while the lava itself acts as support. As in a common CVD process, the quality of the CNTs can be controlled by the synthesis parameters such as flow rate, hydrocarbon to hydrogen ratio and growth temperature. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Novel organometallic fullerene complexes for vehicular hydrogen storage
Authors: Dillon A. C. , Whitney E. , Engtrakul C. , Curtis C. J. , O'Neill K. J. , Parilla P. A. , Simpson L. J. , Heben M. J. , Zhao Y. , Kim Y.‐H. , Zhang S. B. 
Published: September 2007

AbstractTheoretical studies have predicted that scandium can bind to the twelve five‐membered rings in C60. It is then possible to stabilize four dihydrogen ligands (H2) on each Sc atom with a binding energy of ∼30 kJ/mol, ideal for vehicular hydrogen storage. The resulting C60[ScH2(H2)4]12 complex is predicted to be a minimum energy structure with ∼7.0 wt% reversible hydrogen capacity. However, wet chemical synthesis of the calculated η5‐coordinated fullerene complex is unprecedented. The chemistry of C60 is generally olefinic (i.e., η2‐coordination, in which the metal is coordinated to two carbon atoms contributing two electrons to the bonding). Furthermore, stabilization of multiple dihydrogen ligands on a single transition metal has not been demonstrated. Recently we have probed new synthesis techniques in order to coordinate C60 with either Fe, Sc, Cr, Co or Li. The new compounds were characterized with solid‐state nuclear magnetic resonance, and structures have been proposed. All of the structures were found to have unique binding sites for hydrogen employing the technique of temperature programmed desorption. Furthermore, some of the structures were shown to have significant hydrogen capacities with volumetric measurements. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Anisotropy in the X‐ray absorption of vertically aligned single wall carbon nanotubes
Authors: Kramberger C. , Shiozawa H. , Rauf H. , Grüneis A. , Rümmeli M. H. , Pichler T. , Büchner B. , Batchelor D. , Einarsson E. , Maruyama S. 
Published: September 2007

AbstractCarbon nanotubes are archetypical one dimensional systems, with peculiar anisotropic electronic properties. Only recently μm thick films of vertically aligned SWNT became available. The vertical alignment of the nanotube mats allows the realization of scattering geometries promoting specific dipole transitions parallel and normal to the axis of the SWNT. We find well expressed mosaic spreads for the π* and σ * resonances. Full three dimensional modelling of the dipole transitions as well as of the alignment demonstrate polarization dependent X‐ray absorption to be an accurate, versatile non destructive and reliable tool to quantify the alignment of SWNT on a bulk scale. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Metallic bundles of single‐wall carbon nanotubes probed by electron spin resonance
Authors: Simon F. , Quintavalle D. , Jánossy A. , Náfrádi B. , Forró L. , Kuzmany H. , Hauke F. , Hirsch A. , Mende J. , Mehring M. 
Published: September 2007

AbstractC59N magnetic fullerenes inside single‐wall carbon nanotubes (SWCNTs) are used to probe the density of states (DOS) on the host tubes using electron spin resonance (ESR). The C59N radicals are separated by C60 fullerenes to prevent dimerization and C59N–C60 heterodimers are formed at low temperatures. The electron spin–lattice relaxation time, T1, of the heterodimers is deduced from the homogeneous ESR line‐width. The analysis is supported by saturation ESR studies. The inverse of the heterodimer T1 follows a linear behavior in the 20–300 K temperature range, the so‐called Korringa law, evidencing a metallic DOS on all tubes in a bundle. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Special section: Computational Nano‐Photonics
Authors: Busch Kurt , Chigrin Dmitry N. 
Published: September 2007

AbstractThis issue of physica status solidi (b) contains a special section which was guest‐edited by Kurt Busch and Dmitry N. Chigrin. It contains selected contributions presented at the 386th Wilhelm and Else Heraeus Seminar on “Computational Nano‐Photonics” held in Bad Honnef, Germany, 25–28 February 2007.The cover picture demonstrates some of the many computational aspects of the analysis of a dielectric micro‐disc resonator. In the center of the picture, the three‐dimensional intensity distribution of a resonator mode is displayed together with the outline of the micro‐disc's shape. In addition, a strongly coarsened cross‐section of an unstructured computational grid that has been employed for this computation is visualized in the upper right corner. The emission spectrum of a broad‐band source that is located inside the micro‐disc and covers several resonances is shown in the lower left corner. The picture is courtesy of Jens Niegemann, Universität Karlsruhe, Germany.
On the boundedness of the set of stabilizing controllers
Authors: Malik Waqar A. , Darbha Swaroop , Bhattacharyya S. P. 
Published: September 2007

AbstractThis paper shows that the set of rational, strictly proper, robustly stabilizing controllers for single‐input single‐output linear‐time invariant plants will form a bounded (can even be empty) set in the controller parameter space if and only if the order of the stabilizing controller cannot be reduced any further; if the set of proper stabilizing controllers of order r is not empty and the set of strictly proper controllers of order r is bounded, then r is the minimal order of stabilization.The paper also extends this result to characterize the set of controllers that guarantee some pre‐specified performance specifications. In particular, it is shown here that the minimal order of a controller that guarantees specified performance is l iff (1) there is a controller of order l guaranteeing the specified performance and (2) the set of strictly proper, robustly stabilizing controllers of order l and guaranteeing the performance is bounded. Moreover, if the order of the controller is increased, the set of higher‐order controllers which satisfies the specified performance will necessarily be unbounded. This characterization is provided for performance specifications, such as gain margin and robust stability, which require a one‐parameter family of real polynomials to be Hurwitz, where the parameter is in a closed interval. Other performance specifications, such as phase margin and ℋ︁∞ norm, can be reduced to the problem of determining a set of stabilizing controllers that renders a family of complex polynomials Hurwitz. The characterization of the set of controllers for the stabilization of complex polynomials is provided and is used to show the boundedness properties for the set of controllers that guarantee a given phase margin or an upper bound on the ℋ︁∞ norm. Copyright © 2007 John Wiley & Sons, Ltd.
Regulation in bimodal systems
Authors: Wu Zhizheng , Ben Amara Foued 
Published: September 2007

AbstractThis paper considers the regulation problem for bimodal systems against known disturbance and reference signals. Switching between the two plant models as well as between the disturbance and reference signals is defined according to a switching surface. The design of the proposed regulators involves three main steps. First, a set of observer‐based Q‐parameterized stabilizing controllers for the switched system is constructed. The stability and the input/output properties for the resulting closed‐loop switched system with the Q‐parameterized controllers are analysed. Second, regulation conditions for each of the two subsystems in the resulting bimodal switched closed‐loop system are presented. In the third step, regulation conditions for the switched closed‐loop system are developed using two approaches. In the first approach, sufficient regulation conditions are derived based on the closed‐loop system's input–output properties. In the second approach, the forced switched closed‐loop system is transformed into an unforced impulsive switched system using an appropriate coordinate transformation. Hence, the regulation problem for the switched closed‐loop system is transformed into a stability analysis problem for the origin of an impulsive switched system. A regulator synthesis method based on solving some linear matrix inequalities is proposed. Finally, a numerical example is presented to illustrate the effectiveness of the proposed method. Copyright © 2007 John Wiley & Sons, Ltd.
Explicit constructions of global stabilization and nonlinearH∞control laws for a class of nonminimum phase nonlinear multivariable systems
Authors: Lan Weiyao , Chen Ben M. , Lewis Frank L. 
Published: September 2007

AbstractThis paper investigates a global stabilization problem and a nonlinearH∞control problem for a class of nonminimum phase nonlinear multivariable systems. To avoid the complicated recursive design procedure, an asymptotic time‐scale and eigenstructure assignment method is adopted to construct the control laws for the stabilization problem and the nonlinearH∞control problem. A sufficient solvability condition is established onthe unstable zero dynamics of the system for global stabilization problem and nonlinearH∞control problem, respectively. Moreover, based on the sufficient solvability condition, an upper bound of the achievableL2‐gain is estimated for the nonlinearH∞control problem. Copyright © 2007 John Wiley & Sons, Ltd.
Recognition of line graph images in documents by tracing connected components
Authors: Fuda Toshimichi , Omachi Shinichiro , Aso Hirotomo 
Published: September 2007

AbstractUp to the present there has been a great deal of research related to recognition and comprehension of document images. A large amount of this research focused on text although a significant amount of information in graph images within document images is also included. If it is possible to recognize and comprehend a graph image, electronic documents can be used more efficiently. Research on recognition methods focusing on graph images within document images dealt with solid line graph images (bar graphs and markers). This paper proposes a recognition method of graphs focusing on line graph images which do not include markers comprised by solid lines, dotted lines, broken lines, and dash‐dot lines. This paper also shows the effectiveness of this through experimentation. © 2007 Wiley Periodicals, Inc. Syst Comp Jpn, 38(14): 103–114, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/scj.10615
A noise suppression method based on mutual control of spectral subtraction and spectral amplitude suppression
Authors: Furuta Satoru , Takahashi Shinya , Nakajima Kunio 
Published: September 2007

AbstractThis paper discusses a noise suppressor for use in the standard AMR (adaptive multi‐rate) voice codec in 3GPP (3rd Generation Partnership Project). The performance standards (TS 26.077) for 3GPP noise suppressors require both high quality and high noise suppression performance with limited computational complexity. This paper is based on the spectral subtraction method, and discusses the configuration in which spectral subtraction and amplitude suppression are mutually controlled according to the state of the input signal. The improved estimation of the subbandS/N(signal‐to‐noise ratio) for use in the control of spectral subtraction and amplitude suppression is also discussed. The proposed method is evaluated through simulation experiments, and its effectiveness is verified. Subjective evaluation tests (evaluation by third parties) and objective evaluation tests were performed in accordance with 3GPP TS 26.077, and all 3GPP performance requirement standards were met. The system obtained the first performance endorsement from 3GPP in March 2002. © 2007 Wiley Periodicals, Inc. Syst Comp Jpn, 38(14): 90–102, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/scj.20212
Treating shared data in a browsing‐oriented digital library
Authors: Sato Keizo , Nakashima Makoto , Ito Tetsuro 
Published: September 2007

AbstractIt frequently happens that large amounts of data with various formats on computers are shared by multiple users. However, a method of accessing these data efficiently has not been established. This paper considers a browsing‐oriented digital library in which shared data are arranged linearly according to their relationships, and formulates a method of extracting the desired data efficiently. For the data extraction, a browsing method is first described in which relevance possibility is suggested on the basis of the content information and the position information in the directory structure. Then a method is described in which efficient browsing is realized in terms of the relevance judgment cost and the retrieval effectiveness by performing extraction and rearrangement of data with the directory as a unit. The effect of the proposed method was verified by an experiment using data in a university laboratory. A navigator for browsing the shared data has also been designed. © 2007 Wiley Periodicals, Inc. Syst Comp Jpn, 38(14): 79–89, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/scj.20265
Design and implementation of a parameter filter based on virtual bounding rectangles
Authors: Kakiuchi Masatoshi , Morishima Naoto , Sunahara Hideki 
Published: September 2007

AbstractIn this paper, the authors propose a high‐speed implementation of a parameter filter, using a multidimensional space search algorithm with the introduction of virtual bounding rectangles. The authors have proposed and implemented a KUPF architecture for the problem of packet classification reflecting the complex policies of a router. Because parameter filters generally have filters for multiple parameters, the conventional methods for increasing speed are not applicable to KUPF. R‐tree and R*‐tree, which construct a search tree using minimum bounding rectangles and accelerate the search, are known search methods for multidimensional spaces. Meanwhile, this proposal represents filter rules in multidimensional space with the introduction of virtual bounding rectangles, while normalizing differences in the properties of each parameter and applying an R*‐tree. KUPF‐VR, in which this proposal is implemented, had an improved search speed compared to conventional KUPF and was clearly superior in the case of a large number of filter rules, compared to methods specialized for IP packet processing. © 2007 Wiley Periodicals, Inc. Syst Comp Jpn, 38(13): 92–103, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/scj.20287
3D head model generation using full‐face head shape measurement system
Authors: Koyasu Takehiko , Amano Toshiyuki , Sato Yukio 
Published: September 2007

AbstractRecently, the application of human facial shapes has been attracting interest in such fields as authentication, amusement, and medical care. However, the systems now used in practice heavily burden the person undergoing measurement, because a long time is required for measurement and the user must maintain his or her facial expression. The paper considers the measurement of the human face and proposes a fast method for head shape measurement in which the number of projected patterns is decreased by utilizing the continuity of the facial shape and the uniformity of its reflectivity. Specifically, based on the assumption of continuity of the facial shape, the pattern projection of the upper bits is omitted in the spatial coding, and the spatial code is restored by utilizing the continuity of the facial shape. By applying this method, shape measurement with 8‐bit spatial resolution in the depth direction is achieved by five pattern light projection operations. Based on the fact that the reflectivity of the face is almost uniform, binarization is performed without complementary pattern projection, by using average image comparison and local threshold setting. With these measures, the head model can be acquired by the proposed method in 14 pattern imaging operations, compared with 36 pattern imaging operations required in the conventional measurement system based on spatial coding using complementary pattern light projection. © 2007 Wiley Periodicals, Inc. Syst Comp Jpn, 38(13): 82–91, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/scj.20377
Robust face detection under partial occlusion
Authors: Hotta Kazuhiro 
Published: September 2007

AbstractIn this paper, a robust face detection method under partial occlusion is proposed. In recent years, the effectiveness of face detection methods using support vector machines (SVM) has been reported, but in conventional algorithms, one kernel is applied to global features extracted from an image. Global features are easily influenced by partial occlusion, and therefore the conventional algorithms appear not to be robust in the presence of occlusion. Good handling of local features is necessary in order to provide robustness to partial occlusion in face detection methods based on SVM. We introduce a local kernel for good handling of local features in SVM and use summation as the integration method. In the experiment, a comparison was made with SVM based on the conventional global kernel and using face images including occlusions and face images including shadows caused by changes in the direction of the light source. The robustness of the proposed method to occlusion was demonstrated. It was also confirmed that faces could be detected from face images including practical occlusions such as sunglasses or scarves. ©2007 Wiley Periodicals, Inc. Syst Comp Jpn, 38(13): 39–48, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/scj.20614
Fast alignment of 3D geometrical models and 2D grayscale images using 2D distance maps
Authors: Iwashita Yumi , Kurazume Ryo , Konishi Kozo , Nakamoto Masahiko , Hashizume Makoto , Hasegawa Tsutomu 
Published: September 2007

AbstractTo create a textured virtual model of a real object, the 3D geometric model that is generally measured by a laser scanner must be aligned with the 2D image that is obtained from image sensors excluding some sensors for which geometric and photometric information are obtained at the same time. One conventional registration method that has been proposed compares the contour lines of the silhouette image of the 3D geometric model and of the 2D image and estimates the relative positions of both according to iterative calculations. However, a method that uses point correspondences of contour points in the 2D image and contour points of the silhouette image must find the nearest neighboring points for each iterative calculation, and the computational cost is high. Therefore, in this paper, the authors propose a new registration algorithm of grayscale images and 3D geometric models by using 2D distance maps that are constructed by using the Fast Marching Method from the boundary of an object on the grayscale image. They also show the effectiveness of the proposed method by performing simulation experiments and experiments using actual images. © 2007 Wiley Periodicals, Inc. Syst Comp Jpn, 38(14): 52–62, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/scj.20634