bluuebunny/crossref_metadata_2025_split huggingface dataset:
A new receptor model: A direct trilinear decomposition followed by a matrix reconstruction
Authors: Zeng Yousheng , Hopke Philip K. 
Published: May 2005

AbstractIn many cases, monitoring data for ambient airborne particles can be organized in the form of a three‐way data table with one way for chemical species, one for sampling periods and one for sites. A direct trilinear decomposition followed by a matrix reconstruction (DTDMR) is developed to analyze such a data table as a whole. The three‐way data set is composed into three two‐way matrices by a direct trilinear decomposition (DTD). The column vectors of each of the matrices are called ‘source profiles’, ‘emission patterns’ and ‘site coefficients’ respectively. Particulate sources are identified by examining both their source profiles and emission patterns. After the sources have been identified, emission patterns and site coefficients are used to produce a three‐way matrix that gives estimates of mass contributions of sources to the samples collected at every site in every period. By simulation study, not only has the method been verified, but a good indicator has been found that shows the number of factors (i.e. sources) in the system. Unlike other receptor models, DTDMR does not require source profile data and does not involve trial‐and‐error procedures. Since DTDMR identifies sources based on variations in two dimensions, it has a higher potential to distinguish two sources that have similar chemical compositions. The DTDMR model has provided excellent results with simulated data and has been applied in a real world three‐way data set.
Advances in second‐order calibration
Authors: Wang Yongdong , Borgen Odd S. , Kowalski Bruce R. , Gu Ming , Turecek Frantisek 
Published: May 2005

AbstractSeveral multivariate methods are now available for the calibration of second‐order or hyphenated instruments (e.g. GC/MS). When applied to bilinear data, it has been shown that calibration can be performed in the presence of unknown interferences ‐ a significant advantage over first‐order calibration. In this paper, non‐bilinear rank annihilation (NBRA), a method which has the potential of handling, second‐order non‐bi‐linear data, is studied through theoretical analysis and computer simulation. It is found that the second‐order advantage can be carried over to non‐bilinear data if a property defined as net analyte rank (NAR) holds for the analyte of interest. The net analyte signal (NAS) is defined accordingly for second‐order calibration and the analogy to and difference from lower‐order calibration are discussed. With NAS, some analytical figures of merit such as signal‐to noise ratio, selectivity, sensitivity and limit of determination can be calculated for second order calibration. An application to MS/MS data is also given.
Finding suspected causes of measurement error in multivariate environmental data
Authors: Stapanian Martin A. , Garner Forest C. , Fitzgerald Kirk E. , Flatman George T. , Nocerino John M. 
Published: May 2005

AbstractEnvironmental data are usually multivariate, with the variables conforming to some correlation structure. Occasionally, measurements which do not conform in structure or magnitude may occur in one or more variables. It is important (1) to characterize these discordancies in terms of the disturbed variables and the direction and magnitude of the anomalous error and (2) to associate each discordant observation with a specific cause of measurement error in order to prevent further mismeasurement. We describe a procedure for identifying suspected causes of discordant observations in otherwise multinormal data sets. Variables are assigned to groups, each of which is associated with a specific cause of measurement error. Discordant observations are identified with the generalized distance test or the multivariate kurtosis test. Suspected causes of measurement error are identified by repeating the tests with one of the groups of variables omitted in each analysis. The procedures are evaluated with simulated data sets having a correlation structure similar to that of a large environmental data set.
A test of significance for partial least squares regression
Authors: Wakeling Ian N. , Morris Jeff J. 
Published: May 2005

AbstractPartial least squares (PLS) regression is a commonly used statistical technique for performing multivariate calibration, especially in situations where there are more variables than samples. Choosing the number of factors to include in a model is a decision that all users of PLS must make, but is complicated by the large number of empirical tests available. In most instances predictive ability is the most desired property of a PLS model and so interest has centred on making this choice based on an internal validation process. A popular approach is the calculation of a cross‐validated r2 to gauge how much variance in the dependent variable can be explained from leave‐one‐out predictions. Using Monte Carlo simulations for different sizes of data set, the influence of chance effects on the cross‐validation process is investigated. The results are presented as tables of critical values which are compared against the values of cross‐validated r2 obtained from the user's own data set. This gives a formal test for predictive ability of a PLS model with a given number of dimensions.
Constrained background bilinearization with a generalized simulated annealing algorithm
Authors: Xie Yulong , Wang Jihong , Liang Yizeng , Ge Kai , Yu Ruqin 
Published: May 2005

AbstractGeneralized simulated annealing (GSA) is an optimization technique for locating the global optimum. In this paper GSA was used as the optimization procedure in the constrained background bilinearization (CBBL) of two‐way bilinear data in order to reduce the possibility of sinking into local optima. The behaviour of the algorithm and its comparison with the modified Powell algorithm were studied by simulations and real fluorescence excitation–emission data for organic dye mixtures.
The geometry of multivariate object preprocessing
Authors: Deming Stanley N. , Palasota John A. , Nocerino John M. 
Published: May 2005

AbstractThe geometric properties of three common object‐preprocessing transformations (constant sum, or closure; constant length, or normalization; and maximum value, or ratioing) are investigated. An argument is made for using absolute values in the constant sum and maximum value transformations. In general, each transformation distorts the shape and dimensionality of patterns in the data: transformed data lie on (C‐1)‐dimensional surfaces in the original C‐dimensional space. A data set that has been closed by one of these transformations can be reopened if a vector containing the constant sums, constant lengths or maximum values of the original objects was retained. Transformed data sets may be freely interconverted among these three transformations without the loss of information.
Non‐linear least squares refinement with constraints. Evaluation through curve fitting on emulated XPS‐like spectra and application to the analysis of carbon fibres
Authors: Ceipidor Ugo Biader , Cataldi Tommaso R. I. , Desimoni Elio , Salvi Anna Maria 
Published: May 2005

AbstractA non‐linear least squares iterative refinement has been implemented which shows high performance on a multiple‐peak spectrum including baseline or background. Constraints as well as links within a range are introduced to drive the mathematical optimization: each peak parameter (i.e. height, position, Gaussian/Lorentzian mixing ratio and HWHM on both left and right sides) has assigned to it an allowed range of variation and can be strained to be correlated with other parameters belonging either to the same peak (symmetrical peaks) or to other peaks (doublets, triplets, etc.). Peak shapes typical of XP spectra are used and applications in the field of XPS are discussed. Through emulated curves with Poisson distributed noise, the accuracy and precision of back‐calculated (refined) parameters have been estimated. Moreover, a confidence level calculated from X2 and degrees of freedom has been suggested to check the overall fitting of experimental curves where the signal‐to‐noise ratio is a priori unknown. An application to real C ls XP spectra is described as an example and a list of suggestions is given to match operator requirements. Finally, features of NLLSRC are discussed with respect to other approaches.
Direct distance measures in factor analysis spectral resolution
Authors: Neal Sharon L. 
Published: May 2005

AbstractA factor analysis algorithm that estimates the spectra of mixture components using the set of most dissimilar rows and/or columns is described and illustrated. This algorithm uses the distance as a measure of spectral similarity and is suitable for application to a variety of the bilinear matrix‐formatted data types produced by hyphenated and multidimensional analytical techniqes. The algorithm requires that the data matrix contain at least one row or column that corresponds to the pure spectrum of each component to effect accurate spectral resolution. The performance of the method is illustrated using the resolution of excitation and emission spectra of up to four components from experimental fluorescence excitation‐emission matrices (EEMs). In the case of the EEM, characteristic bands in an emission spectrum effect resolution of the excitation spectrum of the corresponding component, while characteristic bands in an excitation spectrum lead to resolution of the corresponding emission spectrum. The use of the set of most dissimilar rows and columns to evaluate the degree of overlap in the component spectra and compare the quality of row and column solutions is also described.
Comments on the DATa ANalysis (DATAN) algorithm and rank annihilation factor analysis for the analysis of correlated spectral data
Authors: Booksh Karl S. , Kowalski Bruce R. 
Published: May 2005

AbstractIt is shown that the DATa ANalysis (DATAN) algorithm can be expressed in terms of rank annihilation factor analysis (RAFA). Subsequent advances in RAFA are applied to DATAN to eliminate the problems and restrictions associated with DATAN. The extension of DATAN in terms of the trilinear decomposition algorithm is discussed.
PCB method applied to material design—computer‐aided synthesis of BiPbSrCaCuOF superconductor
Authors: Liu Hong‐Lin , Chen Yu , Chen Nian‐Yi 
Published: May 2005

AbstractAn inverse mapping method called PCB (principal component backing), in which the point representing an unknown sample from a low‐dimensional principal component subspace is back‐projected to the high‐dimensional original feature space, is proposed. Two sorts of boundary conditions, non‐linear inverse mapping and linear inverse mapping, are used to obtain an accurate solution in the PCB method. The method is applied to the material design of high‐Tc superconductors, predicting the composition and process conditions for the synthesis of F‐doped Bi‐based materials. Samples in the ‘optimal’ region with the highest Tc of the Bi‐based ceramics have been predicted.
Pattern recognition analysis of near‐infrared spectra by robust distance method
Authors: Cho Junghwan , Gemperline Paul J. 
Published: May 2005

AbstractA method for pattern recognition analysis of near‐infrared spectra has been developed using robust distances determined by minimum volume ellipsoid (MVE) estimators of multivariate location and scatter. Classical methods such as the Mahalanobis distance method often fail in the presence of a moderate number of outliers in a training data set, while robust distance methods can tolerate a considerably larger proportion of outliers in a training data set Outliers can be detected by their relatively large robust distances and can be excluded from a training set without a priori knowledge of the nature of the data set. In this paper the properties of a robust distance method are examined using near‐infrared spectra of sulfamethoxazole and mixtures with its major degradation products, sulfanilic acid and sulfanilamide. The robust distance method successfully detected unacceptable samples (71.4%–89.3% (α = 0.05) or 78.6%–92.9% (α = 0.10)) even when they were inadvertently included in the training data set.
Some theoretical results on second‐order calibration methods for data with and without rank overlap
Authors: Kiers Henk A. L. , Smilde Age K. 
Published: May 2005

AbstractGRAM, a method for second‐order calibration, has been introduced by Sanchez and Kowalski and later modified by Wilson, Sanchez and Kowalski. The methods are based on the claim that, in cases without measurement error they yield correct estimates for the concentration ratios and profiles of (rank‐one) analytes present in sample and mixture. This claim has not been proven rigorously. In the present paper, rigorous proofs are given for situations where the claims are valid indeed. In addition, it is shown that PARAFAC, an alternative method for second‐order calibration, can be used to obtain the same results. Next it is shown that the claims do not hold in cases with ‘rank overlap’ (partly overlapping profiles) and it is proven that a procedure by Wang et al. can still be used to assess some of the concentration ratios. A general framework is provided for a variety of second‐order calibration problems and the extent to which quantitative and qualitative information can be expected is given.
A review of robust process design approaches
Authors: Grize Yves L. 
Published: May 2005

AbstractThe aim of this paper is to present a simple structured review of the different approaches to robust process design to clarify their similarities and dissimilarities. It is primarily written for practitioners who wish to understand and compare the main ideas of each approach and to apply them to their work. Two examples are used to illustrate the different approaches and their corresponding data analysis strategies: the first one is a constructed example on a pigment kneading process and the second one is real example dealing with the validation of an HPLC method. A comparison of the different approaches is provided and some practical recommendations are formulated.
Algorithm for finding an interpretable simple neural network solution using PLS
Authors: Bro Rasmus 
Published: May 2005

AbstractThis communication describes the combination of a feedforward neural network (NN) with one hidden neuron and partial least squares (PLS) regression. Through training of the neural network with an algorithm that is a combination of a modified simplex, PLS and certain numerical restrictions, one gains an NN solution that has several feasible properties: (i) as in PLS the solution is qualitatively interpretable; (ii) it works faster than or comparably with ordinary training algorithms for neural networks; (iii) it contains the linear solution as a limiting case. Another very important aspect of this training algorithm is the fact that outlier detection as in ordinary PLS is possible through loadings, scores and residuals. The algorithm is used on a simple non‐linear problem concerning fluorescence spectra of white sugar solutions.
Optimization in organic synthesis. Sequential response surface modelling for obtaining kinetic information. Part 2: An experimental study of the williamson ether synthesis
Authors: Axelsson Anna‐Karin , Nordahl Åke , Carlson Rolf 
Published: May 2005

AbstractIn this work the utility of a new method for determining kinetic parameters by sequential response surface modelling, previously described (Part 1), is shown by applying it to an experimental study of a reaction with known kinetics. The nucleophilic substitution reaction between ethoxide and benzyl chloride, the Williamson ether synthesis, was selected as a model reaction. This reaction is known to proceed with second‐order kinetics. The method gives access to estimates of initial reaction rate which can be further used to obtain estimates of activation energy and reaction order of reactants. The results obtained are in good agreement with the estimated values of these parameters obtained with conventional kinetic experiments.
The deposition of aluminum thin films by CVD using a novel adduct of dimethylaluminum hydride
Authors: Jones Anthony C. , Houlton David J. , Rushwarth Simon A. , Flanagan Julia A. , Brown Juliette R. , Critchlow Gary W. 
Published: May 2005

Thin films of aluminum have an important application in the metallization of silicon devices in very large scale integration technology. In this communication a new precursor, NMe2AlH(NMe2Et)2 has been used for the CVD of high purity aluminum in the temperature range 250–350 °C. In contrast to currently available precursors it is a free flowing and non‐pyrophoric liquid, making it less hazardous and more convenient for use in CVD. magnified image
Novel, convenient, low cost alternative method for film fabrication: Titanium nitride thin films on alumina substrates for automotive applications from a molecular precursor, (CH3)3SiNHTiCl3
Authors: Narula Chaitanya K. , Czubarow Pawel , Seyferth Dietmar 
Published: May 2005

The deposition of titanium nitride films on ceramic substrates from tetra‐ hydrofuran solutions of the title precursor is reported. It is demonstrated that the process, which involves a single dip‐coat—fire sequence, is a viable alternative to the CVD processes currently used, and that it is an economically feasible route for the mass production of porous TiN electrodes. magnified image
A heat‐resisting acid catalyst: Thermal stability and acidity of a thin silica layer on alumina calcined at 1493 K
Authors: Katada Naonobu , Ishiguro Hideaki , Muto Koh‐ichi , Niwa Miki 
Published: May 2005

AbstractThe chemical vapor deposition of a thin layer of silica on alumina is shown to improve the thermal stability of alumina with respect to sintering and to reduce the loss of surface area of alumina during heating. Benzaldehyde‐ammonia titration showed that samples with high stability were almost completely covered by silica. These observations suggest that an ultrathin silica layer, probably a monolayer, thermally stabilizes the surface. Brønsted acidity was observed even after calcination at 1493 K: it was initially diminished by this calcination, but readily recovered on exposure to a humid atmosphere, whereas conventional solid‐acid catalysts are irreversibly deactivated by complete sintering.
Photo‐assisted chemical vapor deposition of gallium sulfide thin films
Authors: Pernot Patrick J. , Barron Andrew R. 
Published: May 2005

Polycrystalline films of gallium sulfide may be deposited from [(tBu)GaS], (see Fig.) by photo‐assisted CVD at temperatures lower than by thermal CVD. It is found that the stoichiometry of the films is dependent on the wavelength window. The films are however found to be of the thermo‐dynamic hexagonal phase rather than the metastable cubic phase produced by thermal CVD. magnified image
A study of the transition between growth of stoichiometric and silicon‐excess silicon carbide by CVD in the system MTS/H2
Authors: Josiek Andrei , Langlais Francis , Bourrat Xavier 
Published: May 2005

AbstractUnder conditions of medium decomposition of MTS (10–90 %), a transition between region A (growth of nearly stoichiometric SiC) and region B (Si‐excess SiC deposition) may be induced by the variations of total flow rate, total pressure or temperature in relatively small intervals. After the modification of one of these parameters, the growth rate reaches rapidly a new stationary value unless the modification leads to a transition from B to A. In this case, the growth rate increases during a transient stage before reaching the steady‐state mode. A growth model is presented which explains these observations. A TEM study confirms a prediction of this model.
Eurocvd 10—A nostalgic retrospect
Authors: Aylett Bernard J. 
Published: May 2005

La Dolce CVD Vita!Professor Aylett captures the flavor of the feast of scientific contributions and the culinary and alcoholic delights enjoyed by delegates at EUROCVD 10 in Lido di Jesolo. This highly successful meeting was the latest in the biennial series and it showed the breadth and depth of the CVD community in the European arena. In particular, the wide range of applications of CVD presented both in lectures and on posters, illustrated the extensive variety of practical targets for CVD workers to aim at in the future.
Thermodynamic approach to the OMCVD of titanium carbide from titanocene dichloride
Authors: Slifirski Joël , Teyssandier Francis 
Published: May 2005

The deposition of TiC on steel at low temperatures is desirable. It can be achieved using readily decomposable precursor molecules, e.g., organometallics. However, this often results in excess carbon in a coating—the Figure shows the effect of precursor composition on the temperature of occurrence of excess carbon—and a deterioration in mechanical properties. This paper examines the theoretical influences of temperature, pressure, and hydrogen dilution on equilibrium carbon incorporation.magnified image
Analysis and modeling of SIPOS deposition in a hot wall tubular reactor. Part I: Review of previous work and experimental study
Authors: Fayolle Francine , Couderc Jean‐Pierre , Duverneuil Patrick 
Published: May 2005

LPCVD reactors, as illustrated in the Figure, are widely used in semiconductor manufacture. Modeling of these reactors has previously been restricted to relatively simple processes such as polysilicon deposition. This paper now examines the deposition of SIPOS (SiOx) by reviewing previous work, by identifying possible homogeneous and heterogeneous reactions, and by presenting new experimental results to complement existing data.magnified image
Metal‐organic CVD of the high‐Tc superconductor YBa2Cu3O7−δ
Authors: Watson Ian M. 
Published: May 2005

AbstractThe great bulk of CVD effort on superconducting oxide materials has concerned MOCVD of the 93 K superconductor YBa2Cu3O7−δ. Most current work involves growth of triaxially oriented YBa2Cu3O7−δ films a few hundred nanometers in thickness on monocrystalline metal oxide substrates at 650–8500C. Optimized MOCVD processes now produce YBa2Cu3O7−δ films with crystallographic quality and electrical properties comparable to the best films prepared by physical vapor deposition techniques, and offer especially attractive opportunities for large‐area growth. Nevertheless, the metal δ‐diketonate precursors used in YBa2Cu3O7−δ MOCVD have limited volatility and other drawbacks, which have motivated extensive background research on barium sources in particular. Non‐traditional methods for delivering precursors to the deposition zone of a reactor, such as aerosol injection and flash vaporization techniques, have also been developed in response to these problems. A diverse range of YBa2Cu3O7−δ MOCVD processes, some involving plasma‐ or photo‐assisted deposition, are in current use. These have been optimized by largely empirical means, although thermodynamic analyses and mechanistic studies offer the prospect of controlling film deposition on a more scientific basis. Unique features of MOCVD in comparison with physical vapor deposition methods include the possibility of controlling film orientation through photochemical effects, and exploitation of the high surface mobility of adsorbed molecular precursors to grow YBa2Cu3O7−δ below 600°C. With reference to potential uses for MOCVD films, near‐term applications in passive microwave devices are considered in greatest detail.