bluuebunny/crossref_metadata_2025_split huggingface dataset:
X‐ray photoelectron microscopic imaging of the chemical bonding state of Si in a rock sample
Authors: Seyama H. , Wang D. , Soma M. 
Published: July 2004

AbstractA microscopic surface analytical technique is desirable for detailed studies of environmental and geochemical surface processes because most of the relevant solid components from natural sources are heterogeneous and have intricate microstructures. Recent advances in XPS instrumentation have allowed chemical mapping of surfaces. This paper demonstrates the imaging of the chemical bonding state of Si in a rock sample (granodiorite) by X‐ray photoelectron microscopy. An Si 2p photoelectron image of the granodiorite was acquired from the boundary between the quartz and biotite phases, and the image was deconvoluted into quartz and biotite components on the basis of the difference (chemical shift) between the Si 2p binding energies of the two minerals. The two phases were clearly distinguishable in the chemical‐bonding‐state images for Si. Copyright © 2004 John Wiley & Sons, Ltd.
In situ UV–visible and IR absorption study of the aggregation of silver colloidal particles via chemisorption of octadecanethiol
Authors: Wadayama T. , Yano H. , Sasaki Y. , Takahashi J. , Hatta A. 
Published: July 2004

AbstractAggregation of silver colloidal particles in the hydrosol via chemisorption of octadecanethiol (ODT) molecules was investigated based on in situ UV–visible transmission and infrared attenuated total reflection (ATR) measurements. As‐prepared silver hydrosol exhibits a single absorption peak at 395 nm because of the plasma resonance of the metal particles. Upon addition of ODT‐dissolved ethanol to the hydrosol, the resonance band red‐shifts and broadens, the detailed features of which depend on the ODT concentration and elapsed time. Both the red‐shift and the broadening are attributed to particle aggregation in the solution via ODT chemisorption. Aggregation on a germanium prism surface by the addition of ODT‐dissolved ethanol to the hydrosol was investigated using infrared ATR spectroscopy. At moderate ODT concentrations, intense aggregation via ODT chemisorption occurs strongly on the prism surface, allowing observation of ODT absorption bands. Angle‐dependent infrared ATR measurements for the ethanol and ODT molecules at the prism/solution interface clearly show that aggregation on the prism surface proceeds via the exclusion of ethanol. Copyright © 2004 John Wiley & Sons, Ltd.
XPS analysis with external bias: a simple method for probing differential charging
Authors: Ertas Gulay , Suzer Sefik 
Published: July 2004

AbstractThe XPS spectra of thermally grown oxide layers on Si, Al, W and Hf substrates have been recorded while the samples were subjected to external d.c. voltage bias. The bias induces additional shifts in the measured binding energy differences between the XPS peaks of the oxide and that of the metal substrate in Si and Al (as probed both in the 2p and the KLL Auger regions), but not in W and Hf (as probed in the 4f region). These bias induced shifts are attributed to differential charging between the oxide layer and the substrate, which in turn is postulated to be related to the capacitance and inversely to the dielectric constant of the oxide layer. Accordingly, silicon dioxide with the smallest dielectric constant undergoes the largest differential charging, aluminium oxide is in the middle and no appreciable charging can be induced in the high‐k tungsten and hafnium oxides, all of which are ∼6 nm thick. Copyright © 2004 John Wiley & Sons, Ltd.
XPS and AES characterization of hydrolysed γ‐mercaptopropyltrimethoxysilane deposited on Al, Zn and Al–43.4Zn–1.6Si alloy‐coated steel
Authors: Bexell Ulf , Grehk Mikael , Olsson Mikael , Gelius Ulrik 
Published: July 2004

AbstractIn this paper Al, Zn and Al–43.4Zn–1.6Si (AlZn) alloy‐coated steel have been treated with the organofunctional silane γ‐mercaptopropyltrimethoxysilane (γ‐MPS). The influence of different metal substrates on the structure and composition of the silane films was investigated with XPS and AES. The films were obtained by dipping the substrates in the silane solution followed by a blow‐dry procedure in nitrogen gas.The results show that the surface concentration of the deposited silane is independent of the metal substrate and that the thickness of the silane film is non‐uniform. The AES measurements indicate that the silane film covers the entire substrate surface and XPS analysis of the silane‐treated substrate surfaces at different take‐off angles indicates that the γ‐MPS molecule is randomly orientated. Also, the results show that the silane is well hydrolysed under the solution conditions used. Finally, in the zinc‐containing silane‐metal systems, i.e. the silane‐treated AlZn and Zn substrates, the results indicate that the γ‐MPS molecules can bond to the substrate surfaces via the thiol group of the molecule. Copyright © 2004 John Wiley & Sons, Ltd.
In situ XPS and SIMS analysis of O2+ beam‐induced silicon oxidation
Authors: Tan S. K. , Yeo K. L. , Wee A. T. S. 
Published: July 2004

AbstractThe chemical composition variation of silicon under 4 keV O2+ ion beam bombardment at different incident angles was studied by in situ small‐area XPS. The changes in secondary ion profile (30Si+, 44SiO+, 56Si2+, 60SiO2+) during oxygen ion beam bombardment also have been monitored. We present a direct correlation of the changes in secondary ion depth profile with surface composition during sputtering. Evolution of the secondary ion profile obtained from SIMS shows similar trends with variation of oxygen concentration in the crater surface measured by XPS. It is shown that when the oxygen ion beam incidence angle is < 40° silicon dioxide is the dominant species on the crater surface and the matrix ion species ratio (MISR) value for 44SiO+/56Si2+ is higher than for 30Si+/56Si2+. For incidence angles of >40°, the formation of sub‐oxide is favoured and thus the MISR value for 44SiO+/56Si2+ is lower than for 30Si+/56Si2. At 40° bombardment there are similar amounts of SiO2 and sub‐oxides present on the crater surface and the MISR values for 44SiO+/56Si2+ and 30Si+/56Si2+ are also similar. Copyright © 2004 John Wiley & Sons, Ltd.
Quantitative analyses of impurities in ZnO
Authors: Sakaguchi Isao , Hishita Syunichi 
Published: July 2004

AbstractProblems on the quantitative analyses of impurities in secondary ion mass spectrometry (SIMS) were revealed by analysing standard samples. One problem is the interference confirmed when 27Al16O, 63Cu and 67Zn16O negative ions were measured, which can be avoided by measuring a high‐resolution mass spectrum. Another problem is that light elements such as hydrogen can be measured accurately only after using a cooling system to reduce the background intensity. These remedies were applied in the quantitative analysis of single‐crystal ZnO grown by hydrothermal and vapour transport techniques. Copyright © 2004 John Wiley & Sons, Ltd.
Summary of ISO/TC 201 Technical Report: ISO/TR 19319: 2003—Surface chemical analysis—Auger electron spectroscopy and x‐ray photoelectron spectroscopy—Determination of lateral resolution, analysis area and sample area viewed by the analyser
Authors: Powell C. J. 
Published: July 2004

AbstractISO Technical Report 19319:2003 contains information on the determination of lateral resolution, analysis area and sample area viewed by the analyser in surface analyses by Auger electron spectroscopy and x‐ray photoelectron spectroscopy. This article provides a brief summary of this information. Copyright © 2004 John Wiley & Sons, Ltd.
Mechanical properties of the Ni filler metal layer in Si3N4 joints measured by nanoindentation
Authors: Miranzo P. , Osendi M. I. , Vergara I. 
Published: July 2004

AbstractNanoindentation experiments were done on Si3N4/Ni/Si3N4 specimens bonded at different temperatures. Tests were carried out in both the ceramic adherent and the metal filler. Results from nanoindentation experiments done across the interlayer verify that a solution of Si atoms in the Ni interlayer did not modify the mechanical properties of the metal (elastic modulus and hardness). The increase in bonding temperature produced an increase in hardness in the metal interlayer but did not affect its elastic modulus. This hardening of the Ni interlayer was related to the decrease in the shear strength of these joints. Copyright © 2004 John Wiley & Sons, Ltd.
X‐ray microanalysis in STEM of short‐term physicochemical reactions at bioactive glass particle/biological fluid interface. Determination of O/Si atomic ratios
Authors: Banchet V. , Jallot E. , Michel J. , Wortham L. , Laurent‐Maquin D. , Balossier G. 
Published: July 2004

AbstractShort‐term physicochemical reactions at the interface between bioactive glass particles and biological fluids are studied and we focus our attention on the measurements of O/Si atomic ratio. The studied bioactive glass is in the SiO2Na2OCaOP2O5K2OAl2O3MgO system. The elemental analysis is performed at the submicrometre scale by scanning transmission electron microscopy associated with energy‐dispersive x‐ray spectroscopy (EDXS) and electron energy‐loss spectroscopy (EELS). We previously developed an EDXS quantification method based on the ratio method and taking into account local absorption corrections. In this way, we use EELS data to determine, by an iterative process, the local mass thickness, which is an essential parameter for correcting absorption in EDXS spectra. After different immersion times of bioactive glass particles in a simulated biological solution, results show the formation of different surface layers at the bioactive glass periphery. Before 1 day of immersion, we observe the presence of an already shown (Si,O,Al)‐rich layer at the periphery. In this paper, we demonstrate that a thin ‘electron dense’ (Si,O)‐layer is formed on top of the (Si,O,Al)‐layer. In this (Si,O)‐layer, depleted in aluminium, we point out an increase of oxygen weight concentration that can be interpreted by the presence of Si(OH)4 groups, which permit the formation of a (Ca,P)‐layer. Aluminium plays a role in the glass solubility and may inhibit apatite nucleation. After the beginning of the (Ca,P)‐layer formation, the size of the ‘electron dense’ (Si,O)‐layer decreases and tends to disappear. After 2 days of immersion, the (Ca,P)‐layer grows in thickness and leads to apatite precipitation. Copyright © 2004 John Wiley & Sons, Ltd.
A sample size computation method for non‐linear mixed effects models with applications to pharmacokinetics models
Authors: Kang Dongwoo , Schwartz Janice B. , Verotta Davide 
Published: July 2004

AbstractWe propose a simple method to compute sample size for an arbitrary test hypothesis in population pharmacokinetics (PK) studies analysed with non‐linear mixed effects models. Sample size procedures exist for linear mixed effects model, and have been recently extended by Rochon using the generalized estimating equation of Liang and Zeger. Thus, full model based inference in sample size computation has been possible. The method we propose extends the approach using a first‐order linearization of the non‐linear mixed effects model and use of the Wald χ2 test statistic. The proposed method is general. It allows an arbitrary non‐linear model as well as arbitrary distribution of random effects characterizing both inter‐ and intra‐individual variability of the mixed effects model. To illustrate possible uses of the method we present tables of minimum sample sizes, in particular, with an illustration of the effect of sampling design on sample size. We demonstrate how (D‐) optimal or frequent sampling requires fewer subjects in comparison to a sparse sampling design. We also present results from Monte Carlo simulations showing that the computed sample size can produce the desired power. The proposed method greatly reduces computing times compared with simulation‐based methods of estimating sample sizes for population PK studies. Copyright © 2004 John Wiley & Sons, Ltd.
A new approach to modelling interactions between treatment and continuous covariates in clinical trials by using fractional polynomials
Authors: Royston Patrick , Sauerbrei Willi 
Published: July 2004

AbstractWe consider modelling interaction between a categoric covariateTand a continuous covariateZin a regression model. HereTrepresents the two treatment arms in a parallel‐group clinical trial andZis a prognostic factor which may influence response to treatment (known as a predictive factor). Generalization to more than two treatments is straightforward. The usual approach to analysis is to categorizeZinto groups according to cutpoint(s) and to analyse the interaction in a model with main effects and multiplicative terms. The cutpoint approach raises several well‐known and difficult issues for the analyst. We propose an alternative approach based on fractional polynomial (FP) modelling ofZin all patients and at each level ofT. Other prognostic variables can also be incorporated by first constructing a multivariable adjustment model which may contain binary covariates and FP transformations of continuous covariates other thanZ. The main step involves FP modelling ofZand testing equality of regression coefficients between treatment groups in an interaction model adjusted for other covariates. Extensive experience suggests that a two‐term fractional polynomial (FP2) function may describe the effect of a prognostic factor on a survival outcome quite well. In a controlled trial, this FP2 function describes the prognostic effect averaged over the treatment groups. We refit this function in each treatment group to see if there are substantial differences between groups. Allowing different parameter values for the chosen FP2 function is flexible enough to detect such differences. Within the same algorithm we can also deal with the conceptually different cases of a predefined hypothesis of interaction or searching for interactions. We demonstrate the ability of the approach to detect and display treatment/covariate interactions in two examples from controlled trials in cancer. Copyright © 2004 John Wiley & Sons, Ltd.
Quantile estimation following non‐parametric phase I clinical trials with ordinal response
Authors: Paul Ranjan K. , Rosenberger William F. , Flournoy Nancy 
Published: July 2004

AbstractA non‐parametric multi‐dimensional isotonic regression estimator is developed for use in estimating a set of target quantiles from an ordinal toxicity scale. We compare this estimator to the standard parametric maximum likelihood estimator from a proportional odds model for extremely small data sets. A motivating example is from phase I oncology clinical trials, where various non‐parametric designs have been proposed that lead to very small data sets, often with ordinal toxicity response data. Our comparison of estimators is performed in conjunction with three of these non‐parametric sequential designs for ordinal response data, two from the literature and a new design based on a random walk rule. We also compare with a non‐parametric design for binary response trials, by keeping track of ordinal data for estimation purposes, but dichotomizing the data in the design phase. We find that a multidimensional isotonic regression‐based estimator far exceeds the others in terms of accuracy and efficiency. A rule by Simon et al. (J. Natl. Cancer Inst. 1997; 89:1138–1147) yields particularly efficient estimators, more so than the random walk rule, but has higher numbers of dose‐limiting toxicity. A small data set from a leukemia clinical trial is analysed using our multidimensional isotonic regression‐based estimator. Copyright © 2004 John Wiley & Sons, Ltd.
A measurement error model with a Poisson distributed surrogate
Authors: Li Liang , Palta Mari , Shao Jun 
Published: July 2004

AbstractWe study a linear model in which one of the covariates is measured with error. The surrogate for this covariate is the event count in unit time. We model the event count by a Poisson distribution, the rate of which is the unobserved true covariate. We show that ignoring the measurement error leads to inconsistent estimators of the regression coefficients and propose a set of unbiased estimating equations to correct the bias. The method is computationally simple and does not require using supplemental data as is often the case in other measurement error analyses. No distributional assumption is made for the unobserved covariate. The proposed method is illustrated with an example from the Wisconsin Sleep Cohort Study. Copyright © 2004 John Wiley & Sons, Ltd.
A simple significance test for quantile regression
Authors: Redden David T. , Fernández José R. , Allison David B. 
Published: July 2004

AbstractWhere OLS regression seeks to model the mean of a random variable as a function of observed variables, quantile regression seeks to model the quantiles of a random variable as functions of observed variables. Tests for the dependence of the quantiles of a random variable upon observed variables have only been developed through the use of computer resampling or based on asymptotic approximations resting on distributional assumptions. We propose an exceedingly simple but heretofore undocumented likelihood ratio test within a logistic regression framework to test the dependence of a quantile of a random variable upon observed variables. Simulated data sets are used to illustrate the rationale, ease, and utility of the hypothesis test. Simulations have been performed over a variety of situations to estimate the type I error rates and statistical power of the procedure. Results from this procedure are compared to (1) previously proposed asymptotic tests for quantile regression and (2) bootstrap techniques commonly used for quantile regression inference. Results show that this less computationally intense method has appropriate type I error control, which is not true for all competing procedures, comparable power to both previously proposed asymptotic tests and bootstrap techniques, and greater computational ease. We illustrate the approach using data from 779 adolescent boys age 12–18 from the Third National Health and Nutrition Examination Survey (NHANES III) to test hypotheses regarding age, ethnicity, and their interaction upon quantiles of waist circumference. Copyright © 2004 John Wiley & Sons, Ltd.
A general statistical principle for changing a design any time during the course of a trial
Authors: Müller Hans‐Helge , Schäfer Helmut 
Published: July 2004

AbstractA general method is presented that allows the researcher to change statistical design elements such as the residual sample size during the course of an experiment, to include an interim analysis for early stopping when no formal rule for early stopping was foreseen, to increase or reduce the number of planned interim analyses, to change time points and the type I error spending function for the further design of interim analyses, or to change the test statistic, the outcome measure, etc. At the time of a pre‐planned interim analysis for early stopping or at any time of an interim look without spending part of the type I error level the method offers the option to completely redesign the remaining part of the trial, without affecting the type I error level. The method is described in the usual Brownian motion model and extended to the general context of statistical decision functions. It is based on the conditional rejection probability of a decision variable. Copyright © 2004 John Wiley & Sons, Ltd.
Revitalizing modifiability of legacy assets
Authors: Veerman Niels 
Published: July 2004

AbstractThe modifiability of Cobol legacy code is discussed and an approach is proposed to improve the modifiability using automatic restructuring transformations. An algorithm is presented that enables the application of these transformations to large industrial Cobol systems. The transformations were adapted to a system of 80 000 lines of code by extending them with new transformations and transformation patterns. The resulting source code is analysed and discussed. Two case studies (over 5 million lines of code in total) with real‐life Cobol programs show the large‐scale application of the transformations. Copyright © 2004 John Wiley & Sons, Ltd.
An assessment strategy for identifying legacy system evolution requirements in eBusiness context
Authors: Aversano Lerina , Tortorella Maria 
Published: July 2004

AbstractThe enactment of e Business processes requires the effective usage of the existing legacy applications in the e Business initiatives. Technical issues are not enough to drive the evolution of the existing legacy applications, but problems concerning the perspectives, strategies, and business of the enterprises have to be considered. In particular, there is a strict relationship between the evolution of the legacy systems and the evolution of the e Business processes.This paper proposes a strategy to extract the requirements for a legacy system evolution from the requirements of the e Business evolution. The proposed strategy aims at characterizing the software system within the whole environment in which its evolution will be performed. It provides a useful set of attributes addressing technical, process, and organizational issues. Moreover, a set of assessment activities is proposed affecting the order in which the attributes are assessed. Copyright © 2004 John Wiley & Sons, Ltd.
A debugging strategy based on the requirements of testing
Authors: Chaim Marcos L. , Maldonado José C. , Jino Mario 
Published: July 2004

AbstractTesting and debugging activities consume a significant amount of the software development and maintenance budget. To reduce this cost, the use of testing information for debugging purposes has been advocated. In general, heuristics are used to select structural testing requirements (nodes, branches and definition–use associations) more closely related to the manifestation of a failure, which are then mapped into a piece of code. The intuition is that the selected piece of code is likely to contain the fault. However, this approach has its drawbacks. Heuristics that select a manageable piece of code are less likely to hit the fault and the piece of code itself does not provide enough guidance for program understanding—a major factor in program debugging. These problems occur because this approach relies only on static information—a fragment of code. We introduce a strategy for fault localization that addresses these problems. The strategy—called the debugging strategy based on the requirements of testing (DRT)—is based on the investigation of indications (or hints) provided at run‐time by data‐flow testing requirements (definition–use associations). Our claim is that the selected definition–use associations may fail to hit the fault site, but still provide information useful for fault localization. The strategy's novelty and attractiveness are threefold: (i) the focus on dynamic information related to testing data; (ii) implementation in state‐of‐the‐practice symbolic debuggers with a low overhead; and (iii) the use of algorithms which consume constant memory and are linear on the number of branches in the program. A case study shows that our claim is valid (for the subject program) and a prototype tool implements the strategy. Copyright © 2004 John Wiley & Sons, Ltd.
Problems within front‐end support
Authors: Kajko‐Mattsson Mira 
Published: July 2004

AbstractWithin corrective maintenance, the front‐end support mainly assists the customer‐ and back‐end maintenance organizations in the communication of corrective maintenance demands. This implies receiving problem reports from customers, transferring them on to the back‐end maintenance organization/vendor, and delivering problem solutions from the back‐end maintenance organization/vendor to the customers. In this paper, we identify problems as experienced within 37 front‐end support organizations in Sweden. Our results show a great variety of problems within the organizations studied. The dominating problems are the complexity of applications, customer knowledge, and complexity of support organizations. Copyright © 2004 John Wiley & Sons, Ltd.