Joint array combining and MLSE for single-user receivers inmultipath Gaussian multiuser channels

The well-known structure of an array combiner along with a maximum likelihood sequence estimator (MLSE) receiver is the basis for the derivation of a space-time processor presenting good properties in terms of co-channel and intersymbol interference rejection. The use of spatial diversity at the receiver front-end together with a scalar MLSE implies a joint design of the spatial combiner and the impulse response for the sequence detector. This is faced using the MMSE criterion under the constraint that the desired user signal power is not cancelled, yielding an impulse response for the sequence detector that is matched to the channel and combiner response. The procedure maximizes the signal-to-noise ratio at the input of the detector and exhibits excellent performance in realistic multipath channels     

Photocrosslinking of elastomer systems—III Ultraviolet light induced reactions in EPDM and EPR blended with or modified by grafting of derivatives of benzophenone

Photocrosslinking experiments were performed in elastomeric polymer films (EPR or EPDM) that either contained benzophenone or some of its derivatives, or had been previously modified (EPDM) by grafting of benzophenone. This latter modification was performed by a series of Friedel-Crafts reactions. The resulting materials were characterized by i.r. and u.v. spectroscopy in conjunction with physical property measurements. The results allowed relationships between the properties of the photosensitizers in their excited states and their efficiency in the crosslinking processes to be established. The results suggest that each coupled polymer-photoinitiator exhibits a particular behaviour. Thus it appeared that, in the presence of oxygen, the hexadiene branches of the terpolymer can undergo various types of reactions. Moreover, the grafting of the photosensitizer onto the elastomer backbone was shown to enhance considerably the crosslinking reaction. It is possible to conclude that oxygen plays a substantial role in the photocrosslinking. Indeed it always enhances crosslink formation. It can be assumed that the photooxidation of the polymer backbone yields alkoxy and hydroperoxy radicals which can act as crosslink sites.     

Composes cyclobutaniques-1, 3 disubstitues—V : Conformation en solution des acides phenyl-3 et cyclohexyl-3 cyclobutanecarboxyliques

Proton nuclear magnetic resonance spectra analysis (250 MHz and LIS) of 3-phenyl and 3-cyclohexyl cyclobutanecarboxylic acids indicate that structures are adopted in solution which are comparable to those of the crystalline state.     

Two Approaches for Sequential Extraction of Radionuclides in Soils: Batch and Column Methods

Abstract

A three-step sequential extraction protocol designed by Community Bureau of Reference (BCR) is applied to two types of soil (sandy and sandy-loam) which had been previously contaminated with a radionuclide aerosol containing ¹³⁴Cs, ⁸⁵Sr and ^110mAg. This scheme is applied using both batch and column methods. The radionuclide distribution obtained with this scheme depends both on the method and on soil type. Compared with the batch method, column extraction is an inadvisable method. Kinetic aspects seem to be important, especially in the first and third fractions. The radionuclide distribution shows that radiostrontium has high mobility, radiocaesium is highly retained by clay minerals whereas Fe/Mn oxides and organic matter have an important role in radiosilver retention.     

4-amino-2,6-dimethyl-5-oxo-3-thioxo-2,3,4,5-tetrahydro-l,2,4-triazine cobalt(II) complexes

Summary Cobalt(II) complexes of 4-amino-2,6-dimethyl-5-oxo-3-thioxo-2,3,4,5-tetrahydro-1,2,4-triazine (taz) were prepared by reacting the triazine with the corresponding cobalt salt. The isolated compounds were of the types: [CoCl₂(taz)], [CoX₂(taz)₂(H₂O)₂] (X = Br or I), [CoX₂(taz)₂] (X = Br, SCN or NO₃) and [Co(taz)₂(H₂O)₂]X₂(X = C1O₄, BF₄ or NO₃). Conductance, magnetic and spectroscopic (i.r. and vis.) data were used for structural assignments. Pseudooctahedral and pseudotetrahedral structures are proposed for the complexes, with the triazine molecule acting either as a monodentate nitrogen-donor or a bidentate nitrogen-sulphur-donor ligand.     

Three approaches to the development of selective bilayer amperometric biosensors for glucose by in situ electropolymerization

Three different glucose oxidase biosensors for the enzymatic determination of glucose, based on bilayer polymer coatings consisting of polypyrrole (PPy) and poly(o-phenylenediamine), were developed. The electrode substrates are Pt metal, carbon paste and an organic conducting salt (tetrathiafulvalene-tetracyanoquinodimethane), which introduces appreciable variability in the electrode construction process. The three sensors were compared with one another and with bare and PPy monolayer-coated sensors in terms of performance in the determination of glucose in a synthetic serum sample. These configurations provide improved selectivity against the interferences of electroactive species such as ascorbic acid and uric acid, frequently present in biological samples, and the differences between them can be taken advantage of in application to different kinds of samples.     

Application of partial least-squares calibration to phosphorimetric data for determination of polycyclic aromatic hydrocarbons in spiked environmental samples

A partial least-squares calibration method is proposed, for the first time, for phosphorescence signals. The proposed method is based on the determination of phenanthrene, fluoranthene, and benz[a]anthracene by room temperature phosphorimetry, using microemulsion solutions. The emission and first-derivative emission spectra of the ternary mixtures were tested to perform the calibration matrix. Improved recoveries were found for the prior differentiation step in the analysis of ternary mixtures of these polycyclic aromatic hydrocarbons in road dust samples. The proposed method yielded recoveries ranging from 93.2 to 115.3%, with relative standard deviations of < 6.8%.     

High-performance liquid chromatographic evaluation of 2-(alpha-thenoylthio)propionylglycine and its two metabolites in biological fluids

A high-performance liquid chromatographic (HPLC) method for determining 2-(alpha-thenoylthio)propionylglycine (TTPG) and its two main metabolites, thiophenecarboxylic acid and thiopronine, in biological samples was developed. TTPG and its metabolites were extracted by solvent partition and then determined by reversed-phase HPLC with UV detection at 245, 295 and 360 nm. This procedure was validated in order to allow the assay of these compounds in plasma and urine samples with sufficiently low detection limits (50 ng/ml for TTPG and TCA and 100 ng/ml for thiopronine) and with good linearity within the concentration range investigated. It was applied to a comprehensive pharmacokinetic investigation of TTPG in healthy volunteers.