bluuebunny/crossref_metadata_2025_split huggingface dataset:
Silicon to nickel‐silicide axial nanowire heterostructures for high performance electronics
Authors: Weber Walter M. , Geelhaar Lutz , Unger Eugen , Chèze Caroline , Kreupl Franz , Riechert Henning , Lugli Paolo 
Published: November 2007

AbstractSilicon to nickel disilicide axial nanowire (NW) heterostructures have been fabricated and investigated extensively. To this end, intrinsic Si‐NWs were grown by chemical vapor deposition using Au as the catalyst. The Si‐NWs were contacted with Ni reservoirs so that upon annealing Ni diffused axially into the NWs. Single‐crystalline NiSi2NW segments were formed at the diffusion path of Ni as proven by high‐resolution transmission electron microscopy images. Further, the axial NiSi2to Si interfaces showed a sharpness of a couple of nanometers. Fully silicided NiSi2‐NWs had maximal resistivities of 98 μΩ cm and conducted current densities of up to 205 MA/cm2before breakdown. Controlled silicidation from both NW ends gave NiSi2/Si/NiSi2axial NW heterostructures, which were implemented to fabricate Schottky contact field effect transistors (FET). The n++‐substrate was used as a common back gate and the Si to NiSi2interfaces formed the Schottky source‐ and drain‐(S/D) contacts to the active region. These Si‐NW SB‐FETs exhibited p‐type behavior, and current densities in the on state of up to 0.8 MA/cm2for 1 V bias, the drain current could be modulated over a range of 107. Moreover, the use of thin gate dielectrics enabled inverse subthreshold slopes as low as 110 mV/dec. These data show an efficient gate control over the devices by only using a back gate, due to an enhanced gate field coupling to the tip‐like S/D‐Schottky contacts. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Absorption of BN nanotubes under the influence of a perpendicular electric field
Authors: Attaccalite Claudio , Wirtz Ludger , Marini Andrea , Rubio Angel 
Published: November 2007

AbstractWe calculate the optical absorption spectra of prototype (6,6) and (9,9) BN nanotubes in the presence of a perpendicular electric field. This model mimics a gated BN nanotube device. Even though the band‐gap of the tubes decreases strongly as a function of the electric field strength, the absorption spectrum of the pure tubes remains remarkably constant up to high field‐strength. We show that, in contrast, the levels which are responsible for defect‐mediated photo‐luminescence are shifted by the electric field. We address the use of BN nanotubes for optoelectronic applications. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Excitons in carbon nanotubes: Diameter and chirality trends
Authors: Capaz Rodrigo B. , Spataru Catalin D. , Ismail‐Beigi Sohrab , Louie Steven G. 
Published: November 2007

AbstractWe provide a closer look into the diameter and chirality dependences of exciton properties in carbon nanotubes, using a variational methodology based on the effective mass and envelope function approximations, supported by ab initio parameters. Experimental measurements of the binding energy are reproduced within 0.02 eV for a large variety of tubes. We also report on the singlet‐triplet energy splittings, which show a 1/d2 diameter dependence. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Investigation of the shift of Raman modes of graphene flakes
Authors: Haluška M. , Obergfell D. , Meyer J. C. , Scalia G. , Ulbricht G. , Krauss B. , Chae D. H. , Lohmann T. , Lebert M. , Kaempgen M. , Hulman M. , Smet J. , Roth S. , Klitzing K. von 
Published: November 2007

AbstractIn the present work, we use Raman spectroscopy as sensitive tool for the characterization of graphene samples. We observed diverse shifts in the position of the Raman mode close to 2650 cm–1 in various as‐prepared graphene flakes. In order to elucidate the reason for this variation, we checked different substrates (Si/SiO2 and Si/Al2O3) and the effect of the annealing of graphene in argon. We find that most of as‐prepared graphene flakes were non‐intentional doped by holes, i.e. by physisorbed water and/or oxygen. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
In situ time‐resolved measurements of carbon nanotube and nanohorn growth
Authors: Geohegan D. B. , Puretzky A. A. , Styers‐Barnett D. , Hu H. , Zhao B. , Cui H. , Rouleau C. M. , Eres G. , Jackson J. J. , Wood R. F. , Pannala S. , Wells J. C. 
Published: November 2007

AbstractGrowth mechanisms of carbon nanotubes are investigated and compared for both high‐ and low‐temperature synthesis methods through experiments utilizing time‐resolved, in situ imaging and spectroscopy. High‐speed videography and pyrometry measured the timeframes for growth for single‐wall carbon nanotubes (SWNTs) and nanohorns (SWNHs) by laser vaporization (LV) at 1150 °C, revealing that C can self‐assemble at high temperatures preferentially into SWNH structures without catalyst assistance at rates comparable to catalyst‐assisted SWNT growth by either laser vaporization or chemical vapor deposition (CVD). Laser interferometry and videography reveal the coordinated growth of vertically‐aligned nanotube arrays (VANTAs) by CVD at 550–900 °C. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Chirality‐specific transport phenomena of isolated single‐walled carbon nanotube
Authors: Jeong Seung Yol , Perello David , Kim Sung Jin , Jang Jin Ho , Kang Bo Ram , Yu Woo Jong , Bae Dong Jae , Yun Minhee , Lee Young Hee 
Published: November 2007

AbstractSingle‐walled carbon nanotube‐field effect transistors (SWCNT‐FETs) have been fabricated using in‐situ thermal chemical vapor deposition. For isolated devices, the resonant Raman spectra confirmed that the full width at half maximum (FWHM) of the radial breathing mode (RBM) peaks was about 4 cm–1, consistent with atomic force microscopy (AFM) images that clearly revealed the individually isolated SWCNTs on the patterned substrate with a diameter of 1.3 nm. Subsequent I –V measurements of the SWCNT‐FET revealed a clear gating effect for samples with semiconducting SWCNTs. The transport phenomena of a device with mixed metallic and semiconducting SWCNTs network were governed by the metallic nanotube with severely suppressed gate modulation. Identification of the chirality of SWCNTs by resonant Raman spectroscopy prior to the I –V characteristics guarantees the validity of working FET devices. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Charge transport across single‐molecule junctions: charge reconfiguration and structural dynamics
Authors: Secker Daniel , Weber Heiko B. 
Published: November 2007

AbstractThe charge transport across single‐molecule junctions is often considered as a pure electronic phenomenon. Analysing experiments performed with the mechanically controlled break junction technique, we show that, additionally, both polarization and dynamic motion of the geometric structure of the molecule give important contributions to the charge transport across single‐molecule junctions. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Electronic properties of graphene
Authors: Novoselov K. S. , Morozov S. V. , Mohinddin T. M. G. , Ponomarenko L. A. , Elias D. C. , Yang R. , Barbolina I. I. , Blake P. , Booth T. J. , Jiang D. , Giesbers J. , Hill E. W. , Geim A. K. 
Published: November 2007

AbstractGraphene is the first example of truly two‐dimensional crystals – it's just one layer of carbon atoms. It turns out that graphene is a gapless semiconductor with unique electronic properties resulting from the fact that charge carriers in graphene obey linear dispersion relation, thus mimicking massless relativistic particles. This results in the observation of a number of very peculiar electronic properties – from an anomalous quantum Hall effect to the absence of localization. It also provides a bridge between condensed matter physics and quantum electrodynamics and opens new perspectives for carbon‐based electronics. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Special issue: Electronic Properties of Novel Nanostructures
Authors: Kuzmany Hans , Dinse Peter , Roth Siegmar , Thomsen Christian 
Published: November 2007

AbstractThis special issue of physica status solidi (b) contains contributions presented at the International Winterschool/Euroconference on Electronic Properties of Novel Materials (IWEPNM 2007). The meeting was held in March 2007 in Kirchberg, Austria.The articles in this issue provide essential information on a wide spectrum of topics, including quantum information, Raman spectroscopy and optics of nanotubes, synthesis of carbon nanotubes, carbon nanotubes and DNA, graphite and graphene, electron and heat transport in carbon nanostructures, composites with carbon nanotubes, as well as on theory and applications of these materials.As in previous years, the meeting was attended by many outstanding researchers from around the world and from a wide spectrum of scientific disciplines. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
First principle study of the cation vacancy in anatase TiO2
Authors: Bai Yu , Chen Qiang 
Published: November 2007

AbstractBased on first principle FP‐LAPW calculations, we have studied the electronic and magnetic properties of anatase TiO2 with Ti cation vacancy. We find that the Ti cation vacancy defect can induce a magnetic moment of about 4μB/supercell. The magnetic moment mainly comes from p‐orbitals of O atoms which surround the Ti vacancy. We also find that the two Ti vacancies in anatase always coupled ferromagnetically. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Matrix‐covariant representation of high‐order configuration interaction and coupled cluster theories
Authors: Luzanov Anatoliy V. 
Published: November 2007

AbstractWe present the closed form of the reduced density matrices (RDMs) of arbitrary order for configuration interaction (CI) wave functions at any excitation level, up to the full CI. A special operator technique due to Bogoliubov is applied and extended. It focuses on constructions of matrix‐covariant expressions independent of the basis set used. The corresponding variational CI equations are given in an explicit form containing the matrices related to conventional excitation operators. A subsequent transformation of the latter to an irreducible form makes it possible to generate the matrix‐covariant representation for coupled cluster (CC) models. Here this transformation is performed for a simplified high‐order CC scheme somewhat reminiscent of the quadratic CI model. A generalized spin‐flip approximation closely related to high‐order CI and CC models is presented, stressing on a possible inclusion of nondynamical and dynamical correlation effects for multiple bond breaking. A derivation of the full CI and simple CC models for systems involving effective three‐electron interactions is also given, thereby demonstrating the capability of the proposed method to deal with complicated many‐body problem. © 2007 Wiley Periodicals, Inc. Int J Quantum Chem, 2008
Determination of long‐acting release octreotide, an octapeptide analogue of somatostation, in human plasma by liquid chromatography/tandem mass spectrometry
Authors: Jiang Yao , Wang Jiang , Wang Yingwu , Du Xiaolin , Zhang Yunhui , Fawcett J. Paul , Gu Jingkai 
Published: November 2007

AbstractA sensitive and selective method for the determination of long‐acting released octreotide in human plasma has been developed based on liquid chromatography/tandem mass spectrometry (LC/MS/MS). Octreotide and the internal standard, triptorelin, were precipitated from the matrix, washed with dichloromethane and subsequently separated by reversed‐phase high‐performance liquid chromatography (HPLC) employing a 1% formic acid/methanol gradient system. Detection was by electrospray ionization mass spectrometry in the positive ion mode using multiple‐reaction monitoring. The assay was linear in the concentration range 0.0500–50.0 ng/mL with intra‐ and inter‐day precision (as relative standard deviation) of <2.95% and <8.37%, respectively. The limit of detection was 0.0200 ng/mL. The method was applied to a pharmacokinetic study of long‐acting released octreotide in healthy volunteers given an intramuscular injection containing 20 mg octreotide. Copyright © 2007 John Wiley & Sons, Ltd.
Shared environment representation for a human‐robot team performing information fusion
Authors: Kaupp Tobias , Douillard Bertrand , Ramos Fabio , Makarenko Alexei , Upcroft Ben 
Published: November 2007

AbstractThis paper addresses the problem of building a shared environment representation by a human‐robot team. Rich environment models are required in real applications for both autonomous operation of robots and to support human decision‐making. Two probabilistic models are used to describe outdoor environment features such as trees: geometric (position in the world) and visual. The visual representation is used to improve data association and to classify features. Both models are able to incorporate observations from robotic platforms and human operators. Physically, humans and robots form a heterogeneous sensor network. In our experiments, the human‐robot team consists of an unmanned air vehicle, a ground vehicle, and two human operators. They are deployed for an information gathering task and perform information fusion cooperatively. All aspects of the system including the fusion algorithms are fully decentralized. Experimental results are presented in form of the acquired multi‐attribute feature map, information exchange patterns demonstrating human‐robot information fusion, and quantitative model evaluation. Learned lessons from deploying the system in the field are also presented. © 2007 Wiley Periodicals, Inc.
Towards heterogeneous robot teams for disaster mitigation: Results and performance metrics from RoboCup rescue
Authors: Balakirsky Stephen , Carpin Stefano , Kleiner Alexander , Lewis Michael , Visser Arnoud , Wang Jijun , Ziparo Vittorio Amos 
Published: November 2007

AbstractUrban Search and Rescue is a growing area of robotic research. The RoboCup Federation has recognized this, and has created the new Virtual Robots competition to complement its existing physical robot and agent competitions. In order to successfully compete in this competition, teams need to field multi‐robot solutions that cooperatively explore and map an environment while searching for victims. This paper presents the results of the first annual RoboCup Rescue Virtual competition. It provides details on the metrics used to judge the contestants as well as summaries of the algorithms used by the top four teams. This allows readers to compare and contrast these effective approaches. Furthermore, the simulation engine itself is examined and real‐world validation results on the engine and algorithms are offered. © 2007 Wiley Periodicals, Inc.
TRESSA: Teamed robots for exploration and science on steep areas
Authors: Huntsberger Terry , Stroupe Ashley , Aghazarian Hrand , Garrett Mike , Younse Paulo , Powell Mark 
Published: November 2007

AbstractLong‐duration robotic missions on lunar and planetary surfaces (for example, the Mars Exploration Rovers have operated continuously on the Martian surface for close to 3 years) provide the opportunity to acquire scientifically interesting information from a diverse set of surface and subsurface sites and to explore multiple sites in greater detail. Exploring a wide range of terrain types, including plains, cliffs, sand dunes, and lava tubes, requires the development of robotic systems with mobility enhanced beyond that which is currently fielded. These systems include single as well as teams of robots. TRESSA (Teamed Robots for Exploration and Science on Steep Areas) is a closely coupled three‐robot team developed at the Jet Propulsion Laboratory (JPL) that previously demonstrated the ability to drive on soil‐covered slopes up to 70 deg. In this paper, we present results from field demonstrations of the TRESSA system in even more challenging terrain: rough rocky slopes of up to 85 deg. In addition, the integration of a robotic arm and instrument suite has allowed TRESSA to demonstrate semi‐autonomous science investigation of the cliffs and science sample collection. TRESSA successfully traversed cliffs and collected samples at three Mars analog sites in Svalbard, Norway as part of a recent geological and astrobiological field investigation called AMASE: Arctic Mars Analog Svalbard Expedition under the NASA ASTEP (Astrobiology Science and Technology for Exploring Planets) program. © 2007 Wiley Periodicals, Inc.
Adaptive teams of autonomous aerial and ground robots for situational awareness
Authors: Hsieh M. Ani , Cowley Anthony , Keller James F. , Chaimowicz Luiz , Grocholsky Ben , Kumar Vijay , Taylor Camillo J. , Endo Yoichiro , Arkin Ronald C. , Jung Boyoon , Wolf Denis F. , Sukhatme Gaurav S. , MacKenzie Douglas C. 
Published: November 2007

AbstractIn this paper, we report on the integration challenges of the various component technologies developed toward the establishment of a framework for deploying an adaptive system of heterogeneous robots for urban surveillance. In our integrated experiment and demonstration, aerial robots generate maps that are used to design navigation controllers and plan missions for the team. A team of ground robots constructs a radio‐signal strength map that is used as an aid for planning missions. Multiple robots establish a mobile ad hoc communication network that is aware of the radio‐signal strength between nodes, and can adapt to changing conditions to maintain connectivity. Finally, the team of aerial and ground robots is able to monitor a small village, and search for and localize human targets by the color of the uniform, while ensuring that the information from the team is available to a remotely located human operator. The key component technologies and contributions include: (a) Mission specification and planning software; (b) exploration and mapping of radio‐signal strengths in an urban environment; (c) programming abstractions and composition of controllers for multirobot deployment; (d) cooperative control strategies for search, identification, and localization of targets; and (e) three‐dimensional mapping in an urban setting. © 2007 Wiley Periodicals, Inc.
Human assisted robotic team campaigns for aquatic monitoring
Authors: Singh Amarjeet , Stealey Michael J. , Chen Victor , Kaiser William J. , Batalin Maxim , Lam Yeung , Zhang Bin , Dhariwal Amit , Oberg Carl , Pereira Arvind , Sukhatme Gaurav S. , Stauffer Beth , Moorthi Stefanie , Caron Dave , Hansen Mark 
Published: November 2007

AbstractLarge‐scale environmental sensing, e.g., understanding microbial processes in an aquatic ecosystem, requires coordination across a multidisciplinary team of experts working closely with a robotic sensing and sampling system. We describe a human‐robot team that conducted an aquatic sampling campaign in Lake Fulmor, San Jacinto Mountains Reserve, California during three consecutive site visits (May 9–11, June 19–22, and August 28–31, 2006). The goal of the campaign was to study the behavior of phytoplankton in the lake and their relationship to the underlying physical, chemical, and biological parameters. Phytoplankton form the largest source of oxygen and the foundation of the food web in most aquatic ecosystems. The reported campaign consisted of three system deployments spanning four months. The robotic system consisted of two subsystems—NAMOS (networked aquatic microbial observing systems) comprised of a robotic boat and static buoys, and NIMS‐RD (rapidly deployable networked infomechanical systems) comprised of an infrastructure‐supported tethered robotic system capable of high‐resolution sampling in a two‐dimensional cross section (vertical plane) of the lake. The multidisciplinary human team consisted of 25 investigators from robotics, computer science, engineering, biology, and statistics.We describe the lake profiling campaign requirements, the robotic systems assisted by a human team to perform high fidelity sampling, and the sensing devices used during the campaign to observe several environmental parameters. We discuss measures taken to ensure system robustness and quality of the collected data. Finally, we present an analysis of the data collected by iteratively adapting our experiment design to the observations in the sampled environment. We conclude with the plans for future deployments. © 2007 Wiley Periodicals, Inc.
Origin and development of ecological philosophy and environmental ethics and their impact on the idea of sustainable development
Authors: Tyburski Włodzimierz 
Published: November 2007

AbstractA critical review of environmental philosophy and environmental ethics is discussed in relation to the idea of sustainable development. The article makes reference to 19th century influences that inspired thought orientated towards protecting the natural environment, and then presents the stages of the development of ecological philosophy, the main standpoints and their representatives. The main features of Polish eco‐philosophical thought are presented together with an outline of the most significant achievements of these disciplines on a global scale. The influence of environmental philosophy and ethics on social aspects of sustainable development is also presented. Copyright © 2007 John Wiley & Sons, Ltd and ERP Environment.
Technical uncertainty in the back‐calculation of occupational exposure to dioxins
Authors: Heinzl Harald , Mittlböck Martina , Edler Lutz 
Published: November 2007

AbstractMembers of a cohort of workers in chemical industry (the so‐called Boehringer cohort) exposed to 2, 3, 7, 8‐tetrachlorodibenzo‐para‐dioxin (TCDD) from 1950 to 1984 were subject in the years 1985–1986 and 1992–1994 to an extensive biomonitoring programme on the TCDD levels of the individual workers. For establishing a dose–response relationship between TCDD‐exposure and potentially carcinogenic response, the individual TCDD concentration–time courses had to be back‐calculated over a period of up to more than four decades. Two back‐calculations were attempted for this sophisticated modelling and estimation task, both based on the same toxicokinetic model but yielding different results.We demonstrate here by means of a computer simulation study that these differences could be plausibly explained by the so‐called technical uncertainty caused by the employment of differently statistical estimation techniques. We show that the estimation techniques perform particularly differently in the presence of workplace misclassification and TCDD measurement error, two complications of exposure assessment that are with high probability affecting concurrently that cohort's data.We conclude that technical uncertainty sensibly enlarges the pool of possible explanations for contradictory empirical results of complex modelling and estimation approaches and should be considered as an obligatory uncertainty analysis step after the primary risk analysis evaluation in epidemiological and environmental studies. Copyright © 2007 John Wiley & Sons, Ltd.