bluuebunny/crossref_metadata_2025_split huggingface dataset:
Kinetic regime of step motion on the Si(111) (1 × 1) surface
Authors: Man K. L. , Tang W. X. , Jin X. F. , Altman M. S. 
Published: November 2006

AbstractThe kinetic regime of step motion on the Si(111) (1 × 1) surface is determined from observations of island decay with low‐energy electron microscopy (LEEM). We have investigated the island decay on the tops of mounds fabricated by a photolithographic method. Prefabricated mounds serve as controllable and reproducible island sources and platforms for decay. Island area during decay exhibits the expected power‐law dependence on time, with exponent, α, that is indicative of the kinetic regime. In order to overcome the basic problem of realizing the thermodynamic limit of island decay on an infinite terrace, the power‐law decay exponent is extrapolated to vanishing island (r)—to—terrace (R) radius ratio, r/R = 0. The dependence of α upon r/R suggests that island decay kinetics is intermediate between the diffusion‐limited (DL) and attachment/detachment‐limited (ADL) regimes. Copyright © 2006 John Wiley & Sons, Ltd.
Electronically induced surface chemistry: localised bond breaking versus delocalisation
Authors: Menzel Dietrich 
Published: November 2006

AbstractSurface photochemistry can be considerably different from the corresponding molecular photochemistry. This is due to the fact that bonding of reactants to a surface induces modifications also in reaction paths via electronically excited states. These changes are of importance in respect of both fundamental and applied research. The past 40 years have seen the development of quite detailed understanding of the underlying effects, in particular in the case of bond breaking, which shows up by desorption of neutral and charged molecules and/or fragments. Recent developments in laser technology and nanostructuring have brought renewed interest to this field. Here a survey is given of the important facts and ideas in this realm. It will be argued that the counterplay between localisation of excitations and their delocalisation by coupling is the decisive effect to be understood. Copyright © 2006 John Wiley & Sons, Ltd.
Microscopy of mesoscopic ferromagnetic systems with slow electrons
Authors: Bauer E. , Belkhou R. , Cherifi S. , Hertel R. , Heun S. , Locatelli A. , Pavlovska A. , Zdyb R. , Agarwal N. , Wang H. 
Published: November 2006

AbstractMesoscopic ferromagnetic systems are not only of practical interest for high density recording and storage devices but also as models of cooperative phenomena in low dimensions. The magnetization distribution in such systems is studied in this paper by X‐ray Magnetic Circular Dichroism Photo Emission Microscopy (XMCDPEEM), using thin rectangular and ring‐shaped patterned Co films and by Spin‐Polarized Low Energy Electron Microscopy (SPLEEM), using epitaxial Fe nanostructures. Copyright © 2006 John Wiley & Sons, Ltd.
The early history and future of the SEM
Authors: Wells Oliver C. , Joy David C. 
Published: November 2006

AbstractThe basic principles of the scanning electron microscope (SEM) were established in the 1930's and early 1940's by Knoll, and then by von Ardenne in Germany and by Zworykin, Hillier and others in America. The SEM was revived by Charles Oatley in a series of PhD projects in the Electrical Engineering Department of Cambridge University in England. The first industrial application followed from the early work of McMullan and Smith in Cambridge and was at the Pulp and Paper Institute in Canada. This was soon followed by the application of the SEM to integrated circuits at Westinghouse in America and by the availability of commercial SEMs in England and Japan. At the present time, the SEM and other microscopic and microanalytical techniques are in a worldwide state of development and are being applied in an increasing number of application areas. Copyright © 2006 John Wiley & Sons, Ltd.
Spectroscopic analysis of the process‐dependent microstructure of ultra‐thin high‐k gate dielectric film systems
Authors: Lysaght Patrick S. , Bersuker Gennadi , Tseng Hsing‐Huang , Jammy Raj 
Published: November 2006

AbstractHfO2 gate dielectric thin films have been exposed to anneal processing in NH3 and N2 ambient in order to decouple the influence of N incorporation from that of the thermal cycle alone. We report on the effectiveness of NH3 processing to introduce N into the dielectric film system during intermediate temperature annealing. Several high‐resolution techniques including electron microscopy with electron energy loss spectra (EELS), rotationally averaged selective area electron diffraction, grazing incidence X‐ray diffraction and synchrotron X‐ray photoelectron spectroscopy (XPS) have been utilized to elucidate chemical composition and crystalline structure differences between samples annealed in NH3 and N2 ambient as a function of temperature. Copyright © 2006 John Wiley & Sons, Ltd.
PEEM with high time resolution—imaging of transient processes and novel concepts of chromatic and spherical aberration correction
Authors: Schönhense G. , Elmers H. J. 
Published: November 2006

AbstractThe potential of time‐resolved photoemission electron microscopy (PEEM) for imaging ultrafast processes and for aberration correction in full‐field imaging is discussed. In particular, we focus on stroboscopic imaging of precessional magnetic excitations via XMCD‐PEEM exploiting the time structure of synchrotron radiation (magnetic field pulse pump–X‐ray probe). In a special bunch‐compression mode at BESSY, a time resolution of about 15 ps has been obtained. Further, we discuss an all‐optical pump–probe technique using femtosecond laser excitation. A highly promising alternative to stroboscopic imaging is an approach using time‐resolved image detection. As a second application of time‐resolved PEEM we discuss potential ways of aberration correction. These approaches go back to the old ideas of Scherzer in the light of state‐of‐the‐art equipment. The excellent time structure of synchrotron radiation or pulsed lasers along with advanced methods of time‐resolved image detection and fast electronic pulsers opens ways for driving the resolution limit of a PEEM into the range of a few nanometers. Copyright © 2006 John Wiley & Sons, Ltd.
Electronic structure of ultrathin Si oxynitrides
Authors: Jin Hua , Oh Suhk Kun , Kang Hee Jae 
Published: November 2006

AbstractWe have investigated the chemical states and the band gap of ultrathin Si oxynitrides on Si(100) by X‐ray photoemission spectroscopy (XPS) and reflection electron energy loss spectroscopy (REELS). Silicon oxynitride thin films were grown by plasma‐nitridation and annealed‐nitridation treatment. XPS results show that for the annealed‐nitride SiON thin films, Si3N and N(SiOx)3 states exist at the interface, while for the plasma‐nitride SiON thin films, Si3N, N(SiOx)3 and SiNO states exist at the surface with trapped N2 molecules. The band gap for the annealed‐nitride SiON thin film is 8.9 eV at the surface but it is reduced to about 8.45 eV at the interface. Meanwhile, the band gap for the plasma‐nitride SiON thin film is 7.4 eV. In addition, REELS turns out to be an excellent method to obtain the band gap and electronic structure in oxide thin films. Copyright © 2006 John Wiley & Sons, Ltd.
Shave‐off depth profiling of transparent conductive films and data analysis of the profile
Authors: Nakamura K. , Ishikawa Y. , Utsumi K. , Iigusa H. , Tanaka R. , Ishizaki Y. , Yamamoto T. , Maekawa A. , Owari M. , Nojima M. , Nihei Y. 
Published: November 2006

AbstractAluminum doped zinc oxide (ZAO) is a promising material for transparent conductive films, but higher conductivity is needed for its use in flat‐panel displays. Its conductivity depends on the deposition conditions, and the segregation of aluminum is suspected as one of causes for its low conductivity. But it has not been confirmed yet because of the low aluminum content in ZAO films.‘Shave‐off depth profiling’ is one of the methods that can be used to analyze such samples. By applying this method, multiple elements can be detected simultaneously and with high sensitivity. Furthermore, even samples with surface roughness can be analyzed accurately.We have acquired the shave‐off depth profile of a ZAO thin film and attempted to obtain depth information. However, when the film thickness is insufficient, it is difficult to obtain the depth information directly from the profile. To solve this problem, we now propose a new data analysis method for the shave‐off depth profile, and apply the method to the depth profiling of the ZAO thin film. Copyright © 2006 John Wiley & Sons, Ltd.
Adsorbed hydrogens and their behavior on Ni(111) surface studied by slow‐positron beam
Authors: Kanazawa I. , Oishi Y. , Hirota K. , Fukutani K. , Nozawa K. , Komori F. 
Published: November 2006

AbstractReemitted slow positrons from the clean Ni(111) surface and the hydrogen‐saturated Ni(111) surface were measured. We suggest that the disordered hydrogen adsorbed structure of the β1 phase contains vacancy‐type defects, and that the number of these defects will grow with time in the case of hydrogen‐saturated Ni(111) surface at 180 K. Copyright © 2006 John Wiley & Sons, Ltd.
Surface structural analysis of h‐BN/Ni (111) by X‐ray photoelectron diffraction excited by Al Kα and Cr Lα lines
Authors: Mochizuki Hidehiro , Amano Kentaro , Nojima Masashi , Owari Masanori , Nihei Yoshimasa 
Published: November 2006

AbstractUsing the Cr Lα (hν = 572.8 eV) line, which has energy lower than conventional lines, X‐ray photoelectron spectroscopy (XPS) and X‐ray photoelectron diffraction (XPED) can be used to achieve surface‐sensitive and light‐element‐sensitive measurements. We prepared hexagonal boron nitride (h‐BN), which is a light‐element material, grown in a monolayer on a Ni (111) surface, and measured h‐BN/Ni(111) by XPS/XPED excited by the Al Kα (hν = 1486.6 eV) line and the Cr Lα line. Finally, we investigated the excitation‐energy dependence of the XPED method with respect to energy of the photoelectrons and discuss the effectiveness of the XPED method using Cr Lα excitation. Copyright © 2006 John Wiley & Sons, Ltd.
Surface modification of industrial alloys induced by long‐term interaction with an ionic liquid
Authors: Bardi U. , Chenakin S. P. , Caporali S. , Lavacchi A. , Perissi I. , Tolstogouzov A. 
Published: November 2006

AbstractThe surface modification of Inconel 600, Naval Brass and AISI 1018 carbon steel after immersion into the [C4mim][Tf2N] ionic liquid (IL) at 225 °C for 20 days has been studied using SIMS, XPS and by surface topography measurements. The trace concentration of alloys' components in the IL solution after the immersion test was measured by inductively coupled plasma‐optical emission spectroscopy (ICP‐OES). Appreciable amounts of carbon, nitrogen, oxygen, sulphur and fluorine were detected on the surface of the alloys after the immersion test because of thermal decomposition of the IL. The corrosion layer formed onto the surface of Inconel was found to be rather thick (ca 400–500 nm) and rough (Ra∝ 100–200 nm) due to the dominant adsorption of the IL decomposition products. At the same time, Inconel exhibited minor weight loss (2.5 × 10−5 g × cm−2) after the immersion test. On the contrary, for Brass, the thickness (70–100 nm) and roughness (Ra∝ 80–100 nm) of the corrosion layer were the smallest among the alloys studied, and the weight loss was the greatest (1.3 × 10−2 g × cm−2). It is assumed that IL decomposition might be catalysed by some metallic atoms, for instance Ni, that, in turn, could slow down the surface corrosion and migration of metal atoms into the ionic liquid. Copyright © 2006 John Wiley & Sons, Ltd.
Developments in cluster randomized trials and Statistics in Medicine
Authors: Campbell M. J. , Donner A. , Klar N. 
Published: November 2006

AbstractThe design and analysis of cluster randomized trials has been a recurrent theme in Statistics in Medicine since the early volumes. In celebration of 25 years of Statistics in Medicine, this paper reviews recent developments, particularly those that featured in the journal. Issues in design such as sample size calculations, matched paired designs, cohort versus cross‐sectional designs, and practical design problems are covered. Developments in analysis include modification of robust methods to cope with small numbers of clusters, generalized estimation equations, population averaged and cluster specific models. Finally, issues on presenting data, some other clustering issues and the general problem of evaluating complex interventions are briefly mentioned. Copyright © 2006 John Wiley & Sons, Ltd.
A boosting approach to flexible semiparametric mixed models
Authors: Tutz G. , Reithinger F. 
Published: November 2006

AbstractIn linear mixed models the influence of covariates is restricted to a strictly parametric form. With the rise of semi‐ and non‐parametric regression also the mixed model has been expanded to allow for additive predictors. The common approach uses the representation of additive models as mixed models. An alternative approach that is proposed in the present paper is likelihood based boosting. Boosting originates in the machine learning community where it has been proposed as a technique to improve classification procedures by combining estimates with reweighted observations. Likelihood based boosting is a general method which may be seen as an extension of L2 boost. In additive mixed models the advantage of boosting techniques in the form of componentwise boosting is that it is suitable for high dimensional settings where many explanatory variables are present. It allows to fit additive models for many covariates with implicit selection of relevant variables and automatic selection of smoothing parameters. Moreover, boosting techniques may be used to incorporate the subject‐specific variation of smooth influence functions by specifying ‘random slopes’ on smooth effects. This results in flexible semiparametric mixed models which are appropriate in cases where a simple random intercept is unable to capture the variation of effects across subjects. Copyright © 2006 John Wiley & Sons, Ltd.
A statistical comparison of different family history scores
Authors: Murad H. , Kalter‐Leibovici O. , Chetrit A. , Freedman L. S. 
Published: November 2006

AbstractFamily history (FH) scores are used for estimating the familial risk (FR), i.e. the level of risk for a particular disease among members of that family. An FH score is created from reports about the disease status of the relatives in each family. The most commonly used score is the dichotomous score (positive when at least one relative is affected), which does not consider the family size, number of affected relatives nor each relative's risk factor profile. Authors have proposed many other FH scores that overcome these deficiencies by using external expected risks adjusted for important risk factors. We consider the use of FH scores in studies, which investigate risk factors for a disease and where family risk is considered as a confounder, and examine through simulations the performance of a variety of FH scores in controlling the FR status. We also examine performance in predicting true FR status.For both criteria, only small differences were found between most of the FH scores, although the dichotomous score performed the poorest. Since the proportion score (the proportion of first‐degree relatives of the index who have the disease) is the simplest to calculate, use of this score seems to be justified. Copyright © 2006 John Wiley & Sons, Ltd.
Computerized adaptive testing for measuring development of young children
Authors: Jacobusse Gert , Buuren Stef van 
Published: November 2006

AbstractDevelopmental indicators that are used for routine measurement in The Netherlands are usually chosen to optimally identify delayed children. Measurements on the majority of children without problems are therefore quite imprecise. This study explores the use of computerized adaptive testing (CAT) to monitor the development of young children. CAT is expected to improve the measurement precision of the instrument. We do two simulation studies—one with real data and one with simulated data—to evaluate the usefulness of CAT. It is shown that CAT selects developmental indicators that maximally match the individual child, so that all children can be measured to the same precision. Copyright © 2006 John Wiley & Sons, Ltd.
Pseudoscore‐based estimation from biased observations
Authors: Hu X. Joan , Schroeder R. Jason , Wang Winfred C. , Boyett James M. 
Published: November 2006

AbstractThere are many practical situations where observation of the primary variableYfor individuals in a population is incomplete and depends on some auxiliary variablesXthat are potentially correlated withY. We consider parameter estimation for the distribution ofYwith the incomplete data, without specifying the underlying association betweenYandX. The approach is based on a class of pseudoscore functions using available information ofX. We demonstrate the consistency and asymptotic normality of the estimators and study their finite‐sample properties in various situationsviasimulation. The methodology is illustrated by an example involving kindergarten readiness skills in children with sickle cell disease. Copyright © 2006 John Wiley & Sons, Ltd.
Adaptive design method based on sum of p‐values
Authors: Chang Mark 
Published: November 2006

AbstractBauer and Kohne proposed an adaptive design using Fisher's combination of independent p‐values based on subsamples from different stages (Biometrics 1994; 50(4):1029–1041). Their method provides great flexibility in the selection of statistical methods for hypothesis testing of subsamples. However, the choices for the stopping boundaries are not flexible enough to meet practical needs (Biometrics 2001; 57(3): 886–891). In this paper, an adaptive design method is proposed using linear combination of the independent p‐values. The method provides great flexibility in the selection of stopping boundaries and no numerical integration is required for the two‐stage designs. The stopping boundaries and p‐values can be calculated manually. The operating characteristics of the adaptive designs are studied using computer simulations with and without sample size adjustment. Examples are presented for superiority and non‐inferiority trials with different endpoints (normal, binary, and survival) under different adaptations. The statistical efficiency of the proposed method is compared with other methods based on conditional power. Copyright © 2006 John Wiley & Sons, Ltd.
Pooling batches in drug stability study by using constant‐width simultaneous confidence bands
Authors: Liu W. , Jamshidian M. , Zhang Y. , Bretz F. , Han X. L. 
Published: November 2006

AbstractOne important study objective in drug stability studies is to estimate the shelf‐life of a drug. A key statistical problem involved in this is how to assess the practical equivalence of different batches of the same drug so that different batches can be subgrouped to produce a single shelf‐life for the drug. In this paper constant‐width simultaneous confidence bands are proposed to quantify the magnitude of difference between different batches, with a particular view to establish the practical equivalence of different batches. This approach is suitable for the situation that the intercepts and slopes of the regression lines for the batches cannot be assumed to be equal. It is shown how constant‐width simultaneous confidence bands can be easily constructed for the multiple comparison of several general linear regression models. In particular, it is shown that constant‐width simultaneous confidence bands have a better chance to establish the equivalence than, and so are preferable to, the hyperbola‐shaped simultaneous confidence bands considered (J. Am. Stat. Assoc. 2004; 99:395–403). Copyright © 2006 John Wiley & Sons, Ltd.
Regression models for mixed Poisson and continuous longitudinal data
Authors: Yang Ying , Kang Jian , Mao Kai , Zhang Jie 
Published: November 2006

AbstractIn this article we develop flexible regression models in two respects to evaluate the influence of the covariate variables on the mixed Poisson and continuous responses and to evaluate how the correlation between Poisson response and continuous response changes over time. A scenario for dealing with regression models of mixed continuous and Poisson responses when the heterogeneous variance and correlation changing over time exist is proposed. Our general approach is first to jointly build marginal model and to check whether the variance and correlation change over timevialikelihood ratio test. If the variance and correlation change over time, we will do a suitable data transformation to properly evaluate the influence of the covariates on the mixed responses. The proposed methods are applied to the interstitial cystitis data base (ICDB) cohort study, and we find that the positive correlations significantly change over time, which suggests heterogeneous variances should not be ignored in modelling and inference. Copyright © 2006 John Wiley & Sons, Ltd.
Influences of top management team incentives on firm risk taking
Authors: Wright Peter , Kroll Mark , Krug Jeffrey A. , Pettus Michael 
Published: November 2006

AbstractIn our work, the influences on subsequent firm risk taking of fixed incentives relative to variable incentives as well as the separate effects on subsequent corporate risk taking of variable incentives are examined. Focusing on the top management team members, we find a higher proportion of incentives that are devoted to fixed incentives relative to variable incentives tend to be inversely associated with subsequent firm risk taking. Managerial stock options are directly and uniformly associated with subsequent corporate risk taking. Executive shareholdings, however, display a curvilinear relationship with subsequent enterprise risk taking. Copyright © 2007 John Wiley & Sons, Ltd.
Are joint venture partners more opportunistic in a more volatile environment?
Authors: Luo Yadong 
Published: November 2006

AbstractThis study examines how joint venture partners' opportunism is influenced by environmental volatility in a drastically changing emerging economy. Building on transaction cost and information‐processing theories, we develop the hypothesis that opportunism increases to cope with industry structural instability, information unverifiability, and law unenforceability, the three interrelated yet distinct characteristics that jointly describe environmental volatility in an emerging economy. Our analysis of 188 foreign joint ventures in an emerging market suggests that opportunism increases with information unverifiability and law unenforceability. These relationships are even stronger when joint ventures depend more on the host country environment, but weaker when joint ventures operate in faster‐growing industries. Finally, opportunism is found to play a mediating role in the relationship between environmental volatility and joint venture performance. Copyright © 2007 John Wiley & Sons, Ltd.