bluuebunny/crossref_metadata_2025_split huggingface dataset:
Use of a new methacrylic monomer, 4,4′‐di(2‐hydroxy‐3‐methacryloyloxypropoxy)benzophenone, in the synthesis of porous microspheres
Authors: Podkościelna Beata , Gawdzik Barbara , Bartnicki Andrzej 
Published: November 2006

AbstractA new aromatic, tetrafunctional methacrylate monomer, 4,4′‐di(2‐hydroxy‐3‐methacryloyloxypropoxy)benzophenone, and its application to the synthesis of porous microspheres are presented. This new monomer was copolymerized with divinylbenzene in the presence of pore‐forming diluents. The properties of the obtained highly crosslinked microspheres were investigated as column packing for high‐performance liquid chromatography. Their porous structures in both dry and wet states were studied and compared with those of poly(divinylbenzene) and the less crosslinked copolymer of 2,3‐epoxypropyl methacrylate and divinylbenzene. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 7014–7026, 2006
Computational study of the Trp‐cage miniprotein based on the ECEPP/3 force field
Authors: Zhan Lixin , Chen Jeff Z. Y. , Liu Wing‐Ki 
Published: November 2006

AbstractUsing a newly developed Monte Carlo global optimization method called basin paving, we have performed an ab initio computation for the structure of Trp‐cage based on the ECEPP/3 force field in vacuo. The lowest energy minimum has been located. Its corresponding configuration is comparable to the native structure of Trp‐cage (PDB code 1L2Y) with a backbone root mean square deviation of 2.24 Å. Proteins 2007. © 2006 Wiley‐Liss, Inc.
Controlling Au/n‐GaAs junctions by partial molecular monolayers
Authors: Haick Hossam , Pelz Jonathan P. , Ligonzo Teresa , Ambrico Marianna , Cahen David , Cai Wei , Marginean Camelia , Tivarus Cristian , Tung Raymond T. 
Published: November 2006

AbstractA dipole‐layer approach is adapted to describe the electrostatic potential and electronic transport through metal/semiconductor junctions with a discontinuous monolayer of polar molecules at the metal/semiconductor interface. The effective barrier height of those junctions, which have small pinholes, embedded in a molecular layer, which introduces a negative {positive} dipole (i.e., a dipole whose negative {positive} pole is the one that is closest to the semiconductor surface) on an n‐type {p‐type} semiconductor, is often “tunable” by the magnitude and density of the dipoles. If the lateral dimensions of a molecule‐free pinhole at the interface exceed the semiconductor depletion width, carrier transport is not influenced by the molecular layer and the “effective” barrier height is the nominal metal/semiconductor barrier height. If the molecular layer introduces a positive {negative} dipole on an n‐type {p‐type} semiconductor, enhanced field emission at edges of small pinholes might lead to a leakage‐ and/or an edge‐current component resulting in an effective barrier height lower than the nominal one. We support these conclusions by direct measurements of the nm‐scale electronic behaviour of a Au/n‐GaAs diode with a discontinuous monolayer of dicarboxylic acids at the interface, using Ballistic Electron Emission Microscopy (BEEM). (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Silicon‐on‐insulator based thin film resistors for quantitative biosensing applications
Authors: Neff Petra A. , Wunderlich Bernhard K. , Lud Simon Q. , Bausch Andreas R. 
Published: November 2006

AbstractField‐effect based semiconductor devices for the label‐free detection of molecular interactions represent a promising development for biosensor applications. Recently, several such devices have been presented for the direct electrical detection of nucleic acids and proteins. However, a detailed and quantitative understanding of experimental observations is still elusive in most cases. Here we employ a recently introduced Silicon‐on‐Insulator (SOI) based field‐effect sensor for the label‐free detection of molecules by their intrinsic charge. We present a theoretical description for the quantitative analysis of the sensor response. A capacitor model was developed which accounts for dielectric effects as well as for Debye screening by mobile ions within the layers of molecules bound to the surface. We successfully applied the model to the detection of charged peptides and multilayers at the functionalized sensor surfaces. The electrical detection of the adsorption of bovine serum albumin (BSA) to the sensor surface is demonstrated and can be explained in terms of a dipolar orientation of the bound molecules. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Advances in growth and optical properties of GaN‐based quantum dots
Authors: Arakawa Yasuhiko , Kako Satoshi 
Published: November 2006

AbstractGaN‐based quantum‐dot systems have received great attention and revealed unique zero‐dimensional features of localized excitons in those quantum dots. In this article, we review recent advances in growth and optical properties of the GaN‐based quantum dots focusing on hexagonal GaN quantum dots, which are unique in terms of the existence of a strong built‐in electric field due to a spontaneous polarization and a piezoelectric field. In addition, we also discuss their potential applications to advanced light‐emitting devices, such as lasers and single‐photon sources. Especially, the application to quantum information devices including single‐photon sources with a GaN quantum dot is a promising direction because the GaN quantum dots have the potential for operation at higher temperatures. For such applications to quantum information technology, fine tuning and controlling of the electronic states are indispensable, which are generally performed via the quantum‐confined Stark effect. We have demonstrated thelarge tunability of the energy level in a GaN quantum dot by externally applying an electric field. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Strained SiGe islands on Si(001): Evolution, motion, dissolution, and plastic relaxation
Authors: Rastelli A. , Stoffel M. , Denker U. , Merdzhanova T. , Schmidt O. G. 
Published: November 2006

AbstractWe report on the morphological evolution of strained SiGe islands epitaxially grown on Si(001). After reviewing the morphological transitions undergone by the islands as their size changes, we present recent results obtained by an approach consisting of “reading the footprints” left by the islands on the Si substrate during growth. Such footprints, which we investigate by a combination of scanning probe microscopy and selective wet chemical etching, are trenches carved in the Si substrate. The study of these trenches allows us to discuss general phenomena occurring during growth or post‐growth annealing, such as coarsening and morphological transitions, surface‐mediated material intermixing and lateral island motion, evolution of plastically relaxed islands and effect on the islands surrounding them. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Carbon nanotube via interconnect technologies: size‐classified catalyst nanoparticles and low‐resistance ohmic contact formation
Authors: Awano Y. , Sato S. , Kondo D. , Ohfuti M. , Kawabata A. , Nihei M. , Yokoyama N. 
Published: November 2006

AbstractWe propose a new approach to fabricating carbon nanotube (CNT) via interconnects for future LSIs, which uses preformed catalyst nanoparticles to grow the CNTs. A newly designed impactor provided size‐classified catalyst particles. For the new approach, we employ a TiN contact layer which is more resistant to oxidation and enables us to form a lower resistance ohmic contact between CNTs and wiring layers. The resultant CNT–via resistance was 0.59 Ω for 2‐µm vias, which is the smallest ever reported. We also study the CNT nucleation process using molecular dynamics and discuss how to remove amorphous carbon from the nucleation process. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Preface: phys. stat. sol. (a) 203/14
Authors: Bougeard Dominique , Finley Jonathan , Grayson Matthew , Tornow Marc 
Published: November 2006

AbstractThe present special issue entitled Frontiers in Semiconductor Nanoscience has been prepared to honor Gerhard Abstreiter on the occasion of his 60th birthday and pay tribute to his long career, during which he has consistently operated at the frontiers in semiconductor physics and nanoscience. The twin issues in pss(a) and pss(b) consist of more than forty contributions from leading scientists in four of the general fields of semiconductor and nanostructure physics in which Gerhard has been most active: (i) quantum transport, (ii) optical properties and coherent phenomena, (iii) nano‐biological systems and (iv) novel materials and nanostructures. As discussed by Günther Bauer in his laudatio, Gerhard has consistently made highly significant contributions to each and every one of these fields throughout his career, often leading to new advances that have had a major impact in the fields of semiconductor nanostructures and condensed matter physics.In addition to providing a fitting tribute to Gerhard's long scientific career, we hope that this issue will stimulate imaginative exploitation of these emerging and rapidly developing fields. We are sure that all contributors, colleagues and collaborators join us in wishing Gerhard a very happy birthday and look forward to working on future problems in the science of semiconductors and their nanostructures. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Influence of Coulomb interactions on electrical conduction through short molecular wires
Authors: Walczak Kamil 
Published: November 2006

AbstractElectrical conduction through a two‐terminal molecular device is studied using non‐equilibrium Green's function (NEGF) formalism. Such a junction is made of a short linear wire which is connected to the metallic electrodes. The molecule itself is described with the help of the Hückel (tight‐binding) model with the electron interactions treated within the extended Hubbard model (EHM), while the coupling to the electrodes is described with the help of a broad‐band theory. Coulomb interactions within the molecular wire are treated by means of the restricted Hartree–Fock (RHF) approximation. In particular, the influence of short‐range and long‐range Coulomb interactions on electrical transport characteristics is discussed in detail. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The role of density imbalance in the νT = 1 exciton condensate state for electron bilayer systems
Authors: Wiersma R. D. , Lok J. G. S. , Dietsche W. , Klitzing K. von , Schuh D. , Wegscheider W. 
Published: November 2006

AbstractWe report on our experimental work involving the ν T = 1 exciton condensate in independently contacted bilayer two‐dimensional electron systems. A phase diagram between the weakly coupled (ν U = 1/2, ν L = 1/2) phase and the strongly coupled ν T = 1 phase is experimentally investigated as a function of d /ℓB and electron density imbalance Δn (≡ [n L – n U]/n T) using a drag current configuration. For imbalanced electron layer densities, small interlayer imbalances lead to strengthening of the excitonic phase. Here density imbalance leads to a phase boundary in the drag layer which is symmetric around zero imbalance. Surprisingly this behavior is not seen for ϱ drive,xx , where an unusual asymmetric behavior around zero imbalance occurs. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Magnetotransport studies on single and coupled modulation‐doped quantum wires fabricated by cleaved edge overgrowth
Authors: Wegscheider Werner , Rother Martin , Deutschmann Rainer , Feil Thomas 
Published: November 2006

AbstractCleaved Edge Overgrowth is employed to fabricate atomically precise single and coupled quantum wires. Single wires were investigated in the diffusive and ballistic transport regimes. In addition to a detailed understanding of the 1D sublevel structure in the complex CEO devices, clear indications of Luttinger liquid behavior of the one‐dimensional electron systems were obtained. Coupled quantum wires were studied in the two limits of large and small separations. In the first case shallow 1D potentials were chosen and an alternative description for commensurability oscillations in weakly modulated two‐dimensional electron systems could be derived. For the coupled quantum wires with small separations and a large potential modulation the validity of the miniband transport picture leading to negative differential conductivity was demonstrated. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Measurement, control, and decay of quantum‐dot spins
Authors: Coish W. A. , Golovach Vitaly N. , Egues J. Carlos , Loss Daniel 
Published: November 2006

AbstractIn this review we discuss a recent proposal to perform partial Bell‐state (parity) measurements on two‐electron spin states for electrons confined to quantum dots. The realization of this proposal would allow for a physical implementation of measurement‐based quantum computing. In addition, we consider the primary sources of energy relaxation and decoherence which provide the ultimate limit to all proposals for quantum information processing using electron spins in quantum dots. We give an account of the Hamiltonians used for the most important interactions (spin–orbit and hyperfine) and survey some of the recent work done to understand dynamics, control, and decoherence under the action of these Hamiltonians. We conclude the review with a table of important decay times found in experiment, and relate these time scales to the potential viability of measurement‐based quantum computing. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Optical control of electron spin dynamics in self‐assembled (In,Ga)As/GaAs quantum dots
Authors: Greilich A. , Oulton R. , Zhukov E. A. , Yugova I. A. , Yakovlev D. R. , Bayer M. , Shabaev A. , Efros Al. L. , Stavarache V. , Reuter D. , Wieck A. 
Published: November 2006

AbstractSpin coherence has been studied in self‐assembled (In,Ga)As/GaAs quantum dots which contain on average a single electron per dot due to n‐type modulation doping. A magnetic field was applied in the Voigt geometry, in order to study the precession of the electron spins which are oriented normal to the field. Here we address the mechanism by which such a normal orientation can be achieved by resonant excitation with circularly polarized laser pulses. Further, we discuss, how long this coherence is maintained within an ensemble of quantum dots. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Structural investigation of hierarchically self‐assembled GaAs/AlGaAs quantum dots
Authors: Lenz A. , Timm R. , Eisele H. , Ivanova L. , Martin D. , Voßebürger V. , Rastelli A. , Schmidt O. G. , Dähne M. 
Published: November 2006

AbstractRecent investigations of self‐organized unstrained inverted GaAs/AlGaAs quantum dots, prepared by a combination of Stranski–Krastanov growth mode and an in situ etching technique, show GaAs quantum dots with large confinement energy and high size homogeneity. Here we present first cross‐sectional scanning tunneling microscopy data of these quantum dots, characterized by a lateral extension of about 35 nm, heights of about 5–6 nm, and a reversed truncated pyramidal shape. We further observe a decomposition of the AlGaAs host layers and a roughening of the AlGaAs/GaAs interfaces. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Spatial properties and coherence of the high density phase in the microcavity optical parametric oscillator
Authors: Skolnick M. S. , Sanvitto D. , Krizhanovskii D. N. , Love A. P. D. , Whittaker D. M. , Roberts J. S. 
Published: November 2006

AbstractThe special issue entitled “Frontiers in Semiconductor Nanoscience” with a total of more than forty contributions from leading scientists in semiconductor and nanostructure physics has been prepared to honor Gerhard Abstreiter, Technische Universität München. The present Part B contains Feature Articles and Original Papers in the areas of quantum transport, optical properties and coherent phenomena. Part A of the special issue on nano‐biological systems, novel materials and nanostructures is published in phys. stat. sol. (a) 203, No. 14 (2006).The cover picture has been taken from the Feature Article [1] by Maurice Skolnick et al. It illustrates a calculation of the signal distribution and photonic potential (white contours) in a microcavity optical parametric oscillator with evidence for strong localisation in the potential minima.This issue also contains articles presented at the 7th International Conference on Excitonic Processes in Condensed Matter held in Winston‐Salem, USA, 26–30 June 2006. They include the Editor's Choice “Optical manipulation of CuCl nanoparticles under an excitonic resonance condition in superfluid helium” by K. Inaba et al. The first author received one of the two EXCON Prizes sponsored by Wiley‐VCH. More contributions from EXCON'06 can be found in phys. stat. sol. (c) 3, No. 10 (2006). (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Polymer‐filler derived ceramics with low shrinkage using PCS/SiC/Al mixture
Authors: Zhu Y. Z. , Huang Z. R. , Dong S. M. , Yuan M. , Jiang D. L. 
Published: November 2006

AbstractActive Al and inert SiC powders were dispersed in the polycarbosilane to manufacture SiC ceramic composites by a new process of active‐filler‐controlled pyrolysis of polymer. 40 wt% of active Al fillers, 40 wt% of inert SiC fillers and 20 wt% of PCS, were homogenized. The samples were obtained by pyrolysis at 1100 °C for different soaking time. The results showed that due to the incorporation of active Al fillers, formation of crystallite phases such as Al4C3, Al4Si3 and AlN occured due to the of reaction of Al particles with the polymer decomposition products and the reactive nitrogen atmosphere. The microstructural and mechanical characterization results of the composites are presented in the paper. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A study of the modeling and analysis of software fault‐detection and fault‐correction processes
Authors: Xie M. , Hu Q. P. , Wu Y. P. , Ng S. H. 
Published: November 2006

AbstractMost of the models for software reliability analysis are based on reliability growth models which deal with the fault detection process. This is done either by assuming that faults are corrected immediately after being detected or the time to correct a fault is not counted. Some models have been developed to relax this assumption. However, unlike the fault‐detection process, few published data sets are available to support the modeling and analysis of both the fault detection and removal processes. In this paper, some useful approaches to the modeling of both software fault‐detection and fault‐correction processes are discussed. Further analysis on the software release time decision that incorporates both a fault‐detection model and fault‐correction model is also presented. This procedure is easy to use and useful for practical applications. The approach is illustrated with an actual set of data from a software development project. Copyright © 2006 John Wiley & Sons, Ltd.
Reliable determination of oxygen and hydrogen isotope ratios in atmospheric water vapour adsorbed on 3A molecular sieve
Authors: Han Liang‐Feng , Gröning Manfred , Aggarwal Pradeep , Helliker Brent R. 
Published: November 2006

AbstractThe isotope ratio of atmospheric water vapour is determined by wide‐ranging feedback effects from the isotope ratio of water in biological water pools, soil surface horizons, open water bodies and precipitation. Accurate determination of atmospheric water vapour isotope ratios is important for a broad range of research areas from leaf‐scale to global‐scale isotope studies. In spite of the importance of stable isotopic measurements of atmospheric water vapour, there is a paucity of published data available, largely because of the requirement for liquid nitrogen or dry ice for quantitative trapping of water vapour. We report results from a non‐cryogenic method for quantitatively trapping atmospheric water vapour using 3A molecular sieve, although water is removed from the column using standard cryogenic methods. The molecular sieve column was conditioned with water of a known isotope ratio to ‘set’ the background signature of the molecular sieve. Two separate prototypes were developed, one for large collection volumes (3 mL) and one for small collection volumes (90 µL). Atmospheric water vapour was adsorbed to the column by pulling air through the column for several days to reach the desired final volume. Water was recovered from the column by baking at 250 °C in a dry helium or nitrogen air stream and cryogenically trapped. For the large‐volume apparatus, the recovered water differed from water that was simultaneously trapped by liquid nitrogen (the experimental control) by 2.6‰ with a standard deviation (SD) of 1.5‰ for δ2H and by 0.3‰ with a SD of 0.2‰ for δ18O. Water‐vapour recovery was not satisfactory for the small volume apparatus. Copyright © 2006 John Wiley & Sons, Ltd.
Robust discrete‐time nonlinear sliding mode state estimation of uncertain nonlinear systems
Authors: Veluvolu K. C. , Soh Y. C. , Cao W. 
Published: November 2006

AbstractIn this paper, we propose a discrete‐time nonlinear sliding mode observer for state and unknown input estimations of a class of single‐input/single‐output nonlinear uncertain systems. The uncertainties are characterized by a state‐dependent vector and a scalar disturbance/unknown input. The discrete‐time model is derived through Taylor series expansion together with nonlinear state transformation. A design methodology that combines the discrete‐time sliding mode (DSM) and a nonlinear observer design is adopted, and a strategy is developed to guarantee the convergence of the estimation error to a bound within the specified boundary layer. A relation between sliding mode gain and boundary layer is established for the existence of DSM, and the estimation is made robust to external disturbances and uncertainties. The unknown input or disturbance can also be estimated through the sliding mode. The conditions for the asymptotical stability of the estimation error are analysed. Application to a bioreactor is given and the simulation results demonstrate the effectiveness of the proposed scheme. Copyright © 2006 John Wiley & Sons, Ltd.
Parsimonious analysis of time‐dependent effects in the Cox model
Authors: Lehr Stephan , Schemper Michael 
Published: November 2006

AbstractCox's proportional hazards model can be extended to accommodate time‐dependent effects of prognostic factors. We briefly review these extensions along with their varying degrees of freedom. Spending more degrees of freedom with conventional procedures (a prioridefined interactions with simple functions of time, restricted natural splines, piecewise estimation for partitions of the time axis) allows the fitting of almost any shape of time dependence but at an increased risk of over‐fit. This results in increased width of confidence intervals of time‐dependent hazard ratios and in reduced power to confirm any time‐dependent effect or even any effect of a prognostic factor. By means of comparative empirical studies the consequences of over‐fitting time‐dependent effects have been explored. We conclude that fractional polynomials, and similarly penalized likelihood approaches, today are the methods of choice, avoiding over‐fit by parsimonious use of degrees of freedom but also permitting flexible modelling if time dependence of a usuallya prioriunknown shape is present in a data set. The paradigm of a parsimonious analysis of time‐dependent effects is exemplified by means of a gastric cancer study. Copyright © 2006 John Wiley & Sons, Ltd.