bluuebunny/crossref_metadata_2025_split huggingface dataset:
Dielectric function representation by B‐splines
Authors: Johs Blaine , Hale Jeffrey S. 
Published: March 2008

AbstractAccurate dielectric function values are essential for spectroscopic ellipsometry data analysis by traditional optical model‐based analysis techniques. In this paper, we show that B‐spline basis functions offer many advantages for param‐ eterizing dielectric functions. A Kramers–Kronig consistent B‐spline formulation, based on the standard B‐spline recursion relation, is derived. B‐spline representations of typical semiconductor and metal dielectric functions are also presented. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Immersion scatterometry for improved nano‐scale topography measurements
Authors: Liu Elson , Terry Fred L. 
Published: March 2008

AbstractSpectroscopic ellipsometry measurement of periodic structures (“scatterometry”) has become a standard method for critical dimension and topography measurement in the integrated circuit industry. As dimensions are reduced, this method may not be adequate for research and process control. Use of immersion mode measurements may extend the usefulness of near UV specular scatterometry. In this paper, we present the first experimental measurements of gratings in water immersion and discuss the issues in achieving improved nano‐topography measurements with this method. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Spectroscopic ellipsometry and photoluminescence investigation of Zn1–x –yBex Mgy Se and Cd1–x –yBex Zny Se crystals
Authors: Wronkowska A. A. , Skowroński Ł. , Wronkowski A. , Firszt F. , Me¸czyńska H. , Łe¸gowski S. , Strzałkowski K. , Arwin H. 
Published: March 2008

AbstractOptical and luminescence properties of the Bridgman‐grown Cd1–x –y Bex Zny Se and Zn1–x –y Bex Mgy Se crystals are reported. Spectroscopic ellipsometry was employed for determination of spectral dependence of the complex dielectric function $ \tilde \epsilon $(E) in the photon energy range 0.75–6.5 eV. Below the absorption edge the refractive indices n (E) of the alloys were modelled using a Sellmeier‐type relation. The excitonic band‐gap energies were estimated from the ellipsometric and photoluminescence measurements. Compositional effects in the ellipsometric and photoluminescence spectra are discussed. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The nearly aligned rotating‐monoplate compensator
Authors: Asar M. , Aspnes D. E. 
Published: March 2008

AbstractA rotating‐compensator polarimeter with a misaligned monoplate compensator generates first, third, and fifth harmonics as well as the zeroth (dc), second, and fourth harmonics that provide information about the sample. We outline a general procedure for calculating the detected intensity with mis‐ aligned components, then provide some results where multiple internal reflections in the component are ignored. The analysis involves several orders of tensors, and a quartic secular equation instead of the usual quadratic of a quadratic. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Exploring the thermal transformation of mesoporous titania using spectroscopic ellipsometry
Authors: Choi S. Y. , Mamak M. , Ozin G. A. , Peiris F. C. 
Published: March 2008

AbstractSpectroscopic ellipsometry was used to investigate the optical properties of a series of 2D‐hexagonal and 3D‐cubic mesoporous titania samples subjected to different annealing temperatures. Below a critical temperature, the dispersion of the index of refraction of the composite structure exhibits strong anisotropy, while above the critical temperature the structure reverts to an isotropic medium. Scanning electron microscopy and X‐ray measurements corroborate the ellipsometry results. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Generalized ellipsometry determination of non‐reciprocity in chiral silicon sculptured thin films
Authors: Schmidt D. , Schubert E. , Schubert M. 
Published: March 2008

AbstractWe report on angle‐resolved reflection‐type generalized ellipsometry investigations of form‐birefringent chiral silicon sculptured thin films. The nanodimensional structures within the sculptured thin films are designed in geometries of left‐handed hollow‐core three‐, four‐, and five‐fold, and solid‐core continuous screws. We identify their structurally induced non‐reciprocal optical properties by comparison between off‐diagonal Mueller matrix elements upon reversal of the light direction. The observed non‐reciprocity cannot be described by the piecewise homogeneous approximation scheme using chiral arrangements of dielectrically anisotropic layers. We show that a simple sequence of light interaction with an ideal isotropic chiral rotator and an arbitrarily anisotropic but non‐chiral surface produces non‐reciprocity. We provide estimates of the optical rotary power of the nanostructures. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Physics of plasma‐based ion implantation & deposition (PBIID) and high power impulse magnetron sputtering (HIPIMS): A comparison
Authors: Anders André 
Published: March 2008

AbstractThe emerging technology of High Power Impulse Magnetron Sputtering (HIPIMS) has much in common with the more established technology of Plasma‐Based Ion Implantation & Deposition (PBIID): both use pulsed plasmas, the pulsed sheath periodically evolves and collapses, the plasma‐sheath system interacts with the pulse‐driving power supply, the plasma parameters are affected by the power dissipated, surface atoms are sputtered and secondary electrons are emitted, etc. Therefore, both fields of science and technology could learn from each other, which has not been fully explored. On the other hand, there are significant differences, too. Most importantly, the operation of HIPIMS heavily relies on the presence of a strong magnetic field, confining electrons and causing their E × B drift, which is closed for typical magnetron configurations. Second, at the high peak power levels used for HIPIMS, 1 kW/cm2 or greater averaged over the target area, the sputtered material greatly affects plasma generation. For PBIID, in contrast, plasma generation and ion processing of the surface (ion implantation, etching, and deposition) are considered relatively independent processes. Third, secondary electron emission is generally considered a nuisance for PBIID, especially at high voltages, whereas it is a critical ingredient to the operation of HIPIMS. Fourth, the voltages in PBIID are often higher than in HIPIMS. For the first three reasons listed above, modelling of PBIID seems to be easier and could give some guidance for future HIPIMS models, which, clearly, will be more involved. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Silver nanocluster containing diamond like carbon
Authors: Schwarz F. , Thorwarth G. , Wehlus T. , Stritzker B. 
Published: March 2008

AbstractApplying Diamond Like Carbon (DLC) as medical coating has become well established since large scale plasma processes like Plasma Immersion Ion Implantation and Deposition (PIII&D) are available. Now the focus of research lies on systematic modification of certain biological relevant properties and the most recent field of interest turned to generating antimicrobial behaviour. This is desirable for medical tools as well as for different types of medical implants. Since silver and copper are known to provide a bactericidal effect, one tries to introduce clusters of these noble metals into the carbon matrix.The basic principle of the method presented is to convert a metal containing polymer film into DLC by ion bombardment. In this paper the hydrogenated DLC matrix is characterized and the evolution of the metal particles is studied. By means of film composition (RBS/ERD), bonding structure (Raman spectroscopy) and hardness (nanoindentation), the dependency of these material properties on ion species, energy and fluence is investigated. TEM imaging is used to visualize the film structure.Upon ion irradiation of the polymer films, increased density and considerable loss of hydrogen can be observed, which both are controlled by ion fluence and mass. The crosslinking of the carbon network, caused by hydrogen drive out as well as atomic displacements in collision cascades, results in the formation of a‐C:H. The silver particles in the film some ion induced growth, but still remain as nanoclusters in the a‐C:H matrix. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Conduction band filling in In‐rich InGaN and InN under hydrostatic pressure
Authors: Franssen G. , Kamińska A. , Suski T. , Gorczyca I. , Christensen N. E. , Svane A. , Lu H. , Schaff W. J. , Dimakis E. , Georgakilas A. , Che S.B. , Ishitani Y. , Yoshikawa A. 
Published: March 2008

AbstractWe demonstrate the effect of conduction band shape evolution of InGaN with increasing In content and applying hydrostatic pressure. The influence of conduction band filling on the hydrostatic pressure dependence of photoluminescence in In0.7Ga0.3N and InN is investigated. It is found that the PL pressure coefficient dEPL/dp of InN changes from ∼27 meV/GPa to ∼21 meV/GPa when the electron concentration increases from 3.6×1017 cm–3 to 1.1×1019 cm–3. In contrast, no significant change of dEPL/dp with electron concentration was observed for In0.7Ga0.3N. We conclude that the pressure sensitivity of the Fermi level, which is responsible for the lowering of dEPL/dp with respect to dEG/dp in InN, is much less prominent in In0.7Ga0.3N than in InN. We attribute this difference to the larger band gap of In0.7Ga0.3N, which lowers the pressure sensitivity of m*. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Dislocation annihilation in GaN with multiple MgxNy/GaN buffer layers by metal organic chemical vapor deposition
Authors: Fu Y. K. , Tun C. J. , Kuo C. H. 
Published: March 2008

AbstractUnintentionally doped GaN epitaxial layers with a conventional single low‐temperature (LT) GaN buffer layer and with multiple MgxNy/GaN buffer layers were grown on sapphire substrates by metal organic chemical vapor deposition (MOCVD). X‐ray Photoelectron Spectroscopy (XPS) result reveals Mg 2p core‐level spectra from the 12 pairs of MgxNy/GaN buffer layers. The multiple MgxNy/GaN buffer layers exhibit a low nuclei density, increasing the volume of defect‐free regions and reducing the dislocations associated with the grain boundaries. Therefore, the GaN with multiple MgxNy/GaN buffer layers reveals an asymmetrical reflection (102) with a small full‐width at half‐maximum (FWHM), and a higher mobility, lower background concentration and lower etching pit density (EPD) than the GaN with the LT GaN buffer layer. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Growth of nonpolar cubic GaN/AlN multiple quantum wells with intersubband transitions for 1.5 µm applications
Authors: As D. J. , Schörmann J. , Tschumak E. , Lischka K. , DeCuir E. A. , Manasreh M. O. 
Published: March 2008

AbstractCubic GaN/AlN short‐period multiple quantum well structures were grown at 720 oC by plasma‐assisted molecular beam epitaxy on free standing 3C‐SiC substrates. The samples consist of 100 nm thick GaN buffer and 20 periods of GaN/AlN active regions. The thickness of the AlN barrier is 1.35 nm for all samples, while the thickness of the GaN well varies between 1.6 nm–2.10 nm depending on the samples. The periodicity of the GaN/AlN active regions was confirmed by the presence of several peaks in the high resolution x‐ray diffraction (HRXRD) spectra. The thickness of the total period was estimated by fitting the HRXRD data using a dynamic scattering theory. Room temperature measurements of the optical absorption spectra of the intersubband transitions were obtained using a Bruker IFS‐125HR spectrometer. The peak position wavelengths of these transitions were observed in the spectral region of 1.5–2.0 µm and confirmed theoretically by using a self‐consistent Poisson‐Schrödinger model. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
An observational study and quantification of the actives in a supplement with Sambucus nigra and Asparagus officinalis used for weight reduction
Authors: Chrubasik Cosima , Maier Thorsten , Dawid Corinna , Torda Thomas , Schieber Andreas , Hofmann Thomas , Chrubasik Sigrun 
Published: March 2008

AbstractThe aim of the study was to obtain information on the content of co‐active compounds of a food supplement recommended as a weight reduction diet and on its short‐term effectiveness and safety as a starter for lifestyle change. Eighty participants completed the protocol. The Sambucus nigra L. berry juice enriched with flower extract and tablets containing berry powder and flower extract provided a total of 1 mg anthocyanins, 370 mg flavonol glycosides and 150 mg hydroxycinnamates per day; the Asparagus officinalis L. powder tablets provided 19 mg saponins per day. After the diet, the mean weight, blood pressure, physical and emotional well‐being and the quality of life had significantly improved (ITT analysis). The effectiveness and tolerability of the regimen were rated as very good or good by most of the completers. It remains to be established if any particular compounds contribute to the efficacy of the diet. Copyright © 2008 John Wiley & Sons, Ltd.
Transport of aspalathin, a Rooibos tea flavonoid, across the skin and intestinal epithelium
Authors: Huang Miao , du Plessis Jeanetta , du Preez Jan , Hamman Josias , Viljoen Alvaro 
Published: March 2008

AbstractSince Rooibos tea contains high levels of flavonoid antioxidants with potential health benefits when taken orally or applied topically, the quantity of the antioxidants crossing the physiological barriers is of scientific, clinical and commercial importance. This study investigated the in vitro transport of aspalathin, a unique flavonoid constituent of Rooibos tea, across intestinal epithelial cells and the human skin. The transport studies were conducted for both pure aspalathin solutions and extracts from unfermented (or green) Rooibos (Aspalathus linearis) aerial plant material across human abdominal skin in vertical Franz diffusion cells and Caco‐2 cell monolayers in Transwell 6‐well plates. The results obtained from the percutaneous permeation studies demonstrated that only 0.01% of the initial aspalathin dose from both the test solution and extract permeated through the skin, which was in accordance with the prediction from its log P value of −0.347. A portion of 0.07% of the initial aspalathin dose penetrated the different layers of the skin for the green Rooibos extract solution and 0.08% for the pure aspalathin solution. The transport of aspalathin across Caco‐2 cell monolayers was concentration dependent and reached almost 100% (Papp = 20.93 × 10−6 cm/s) of the initial dose in the highest concentration tested for the extract, while it was only 79.03% (Papp = 15.34 × 10−6 cm/s) of the initial dose for the highest concentration of the aspalathin solution. Copyright © 2008 John Wiley & Sons, Ltd.
Investigation of volatile biomarkers in liver cancer blood using solid‐phase microextraction and gas chromatography/mass spectrometry
Authors: Xue Ruyi , Dong Ling , Zhang Si , Deng Chunhui , Liu Taotao , Wang Jiyao , Shen Xizhong 
Published: March 2008

AbstractSolid‐phase microextraction (SPME) followed by gas chromatography/mass spectrometry (GC/MS) was used for the detection of liver cancer volatile biomarkers. Headspace SPME conditions (fiber coating, extraction temperature and extraction time) and desorption conditions were optimized and applied to the determination of volatiles in human blood. Between the liver cancer group (n = 19) and the normal group (n = 18), positive rates of 19 volatile compounds among the total of 47 detected were found to be different with statistical significance (p < 0.05, chi‐squared test). We suggested hexanal, 1‐octen‐3‐ol and octane, of the 19 compounds, as biomarkers of liver cancer with clinical diagnostic value. The sensitivity and specificity of 94.7% and 100% for hexanal, 84.2% and 100% for 1‐octen‐3‐ol, and 89.5% and 100% for octane were obtained, respectively, after the cutoff values had been properly established. These results show that SPME‐GC/MS is a simple, rapid and sensitive method for the investigation of volatile disease markers in human blood. Copyright © 2008 John Wiley & Sons, Ltd.
Including environmental flow requirements as part of real‐time water resource management
Authors: Hughes D. A. , Mallory S. J. L. 
Published: March 2008

AbstractSouth African water resources legislation requires that environmental flow requirements are included as part of water resource management. An operational management method is presented that relies upon simulating natural flow conditions based on inputs of near real‐time observations of rainfall and a set of operating rules. The operating rules define the reservoir releases and water use supply curtailments that ensure downstream environmental flow objectives will be met. The focus is on managing the variability of continuous low flows, while a suitable method for managing event‐based high flow releases remains elusive. The main limitation to the successful implementation of the low flow approach is the lack of legislated control over run‐of‐river water abstractions. While this limitation is expected to be overcome, as the provisions of new legislation are implemented, water managers may still lack the capacity to exercise the necessary controls over abstraction. There is no reason why the method could not be applied outside South Africa, given compatibility in the definition of environmental flow requirements. Copyright © 2008 John Wiley & Sons, Ltd.
Strategic entrepreneurship, collaborative innovation, and wealth creation
Authors: Ketchen David J. , Ireland R. Duane , Snow Charles C. 
Published: March 2008

AbstractStrategic entrepreneurship refers to firms' pursuit of superior performance via simultaneous opportunity‐seeking and advantage‐seeking activities. Both small and large firms face impediments while pursuing strategic entrepreneurship. While small firms' opportunity‐seeking skills may be strong, their limited knowledge stocks and lack of market power inhibit their ability to enact the competitive advantages necessary to appropriate value from opportunities the firms choose to pursue. In contrast, large firms are skilled at establishing competitive advantages, but their heavy emphasis on the efficiency of their existing businesses often undermines their ability to continuously explore for additional opportunities. Building on a variety of theories, including network, learning, resource‐based, and real options, we suggest that collaborative innovation can enable both types of firms to overcome their respective challenges. Collaborative innovation is the pursuit of innovations across firm boundaries through the sharing of ideas, knowledge, expertise, and opportunities. For small firms, we contend that pursuing entrepreneurship collaboratively allows them to preserve their creativity and flexibility while mitigating the inherent liabilities of smallness. We argue that collaborative innovation permits large firms to exploit their advantage‐creating skills while concurrently exploring for opportunities outside their current domain. Thus, small and large firms that learn how to integrate strategic entrepreneurship and collaborative innovation are well positioned to create wealth. Copyright © 2008 Strategic Management Society.
Entrepreneurial actions, innovation, and appropriability
Authors: Burgelman Robert A. , Hitt Michael A. 
Published: March 2008

AbstractEntrepreneurs take strategic action to create value. They can do so individually or collaboratively, and currently researchers are interested in learning the extent to which collaboration can increase the total entrepreneurial value created. Taking entrepreneurial strategic action naturally involves the pursuit of self‐interest, but entrepreneurial self‐interest can only be served if it simultaneously serves collective interests, such as those of customers, investors, partners, and other relevant constituencies. Currently, researchers are also interested in identifying the most effective ways in which individual and collective interests can be jointly pursued. Copyright © 2008 Strategic Management Society.
Sample designs for measuring the health of small racial/ethnic subgroups
Authors: Elliott Marc N. , Finch Brian K. , Klein David , Ma Sai , Do D. Phuong , Beckett Megan K. , Orr Nathan , Lurie Nicole 
Published: March 2008

AbstractMost national health surveys do not permit precise measurement of the health of racial/ethnic subgroups that comprise <1 per cent of the U.S. population. We identify three potentially promising sample design strategies for increasing the accuracy of national health estimates for a small target subgroup when used to supplement a small probability sample of that group and apply these strategies to American Indians/Alaska Natives (AI/AN) and Chinese using National Health Interview Survey data. These sample design strategies include (1) complete sampling of targets within households, (2) oversampling selected macrogeographic units, and (3) oversampling from an incomplete list frame.Stage (1) is promising for Chinese and AI/AN; (2) works for both groups, but it would be more cost‐effective for AI/AN because of their greater residential concentration; (3) is somewhat effective for groups like Chinese with viable surname lists, but not for AI/AN. Both (2) and (3) efficiently improve measurement precision when the supplement is the same size as the existing core sample, with diminishing additional returns as the supplement grows relative to the core sample, especially for (3). To avoid large design effects, the oversampled geographic areas or lists must have good coverage of the target population. To reduce costs, oversampled geographic tracts and lists must consist primarily of targets.These techniques can be used simultaneously to substantially increase effective sample sizes (ESSs). For example, (1) and (2) in combination can be used to multiply the nominal sample size of AI/AN or Chinese by 8 and the ESS by 4. Copyright © 2008 John Wiley & Sons, Ltd.
Functional Fe3O4/TiO2 Core/Shell Magnetic Nanoparticles as Photokilling Agents for Pathogenic Bacteria
Authors: Chen Wei‐Jen , Tsai Pei‐Jane , Chen Yu‐Chie 
Published: March 2008

AbstractA photokilling approach for pathogenic bacteria is demonstrated using a new type of magnetic nanoprobe as the photokilling agent. In addition to their magnetic property, the nanoprobes have other features including a photocatalytic property and the capacity to target bacteria. The nanoprobes comprise iron oxide/titania (Fe3O4@TiO2) core/shell magnetic nanoparticles. As dopamine molecules can self‐assemble onto the surface of the titania substrate, dopamine is used as the linker to immobilize succinic anhydride onto the surfaces of the Fe3O4@TiO2 nanoparticles. This is followed by the immobilization of IgG via amide bonding. We demonstrate that the IgGFe3O4@TiO2 magnetic nanoparticles not only have the capacity to target several pathogenic bacteria, but they also can effectively inhibit the cell growth of the bacteria targeted by the nanoparticles under irradiation of a low‐power UV lamp within a short period. Staphylococcus saprophyticus, Streptococcus pyogenes, and antibiotic‐resistant bacterial strains, such as multiantibiotic‐resistant S. pyogenes and methicillin‐resistant Staphylococcus aureus (MRSA), are used to demonstrate the feasibility of this approach.