ON THE CONVERGENCE OF THE RELAXATION METHODS FOR POSITIVE DEFINITE LINEAR SYSTEMS

1.IntroductionTheclassicaliterativemethods,suchastheJacobimethod,theGauss-SeidelmethodandtheSORmethod,aswellastheirsymmetrizedvariants,playanimportantroleforsolvingthelargesparsesystemoflinearequationsInaccordancewiththebasicextrapolationprincipleofthelineariterativemethod,Hadjidimos[1]furtherproposedaclassofacceleratedoverrelaxation(AOR)methodforsolyingthelinearsystem(1.1)in1978.Thismethodincludestwoarbitraryparameters,andtheirsuitablechoicesnotonlycannaturallyrecovertheJacobi,theGauss-S…     

Lefschetz Formulae for p-Adic Groups

In this paper,Lefschetz formulae for torus actions on p-adic groups are proven. These are similar to comparable formulae for real Lie groups.Applications lie in the realm of dynamical zeta functions.     

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HT-7中性束诊断电源系统的计算机控制系统由PLC、工控机、逻辑控制和定时单元等组成。对起弧、束流引出等实验进行了研究。在多种参数下,通过调节弧压、进气量等观察了其对弧流的影响。初步实验结果表明,在高压35kV、弧流80A的情况下,束电流可以达到3.6A,引出的中性束流功率可以稳定地达到50kW以上。     

Optical biosensor for pharmaceuticals, antibiotics, hormones, endocrine disrupting chemicals and pesticides in water: Assay optimization process for estrone as example

Certain contaminants at trace concentrations in surface waters can have dramatic effects on the hormonal system of organisms in the aquatic environment. Therefore, immunoanalytical methods at a very low limit of detection (LOD) and a low limit of quantification (LOQ) are becoming more and more important for environmental analysis and especially for monitoring drinking water quality. Environmental monitoring of antibiotics, hormones, endocrine disrupting chemicals, and pesticides in real water samples (e.g. surface, ground or drinking water) with difficult matrices places high demands on chemical analysis. Biosensors have suitable characteristics such as efficiency in allowing very fast, sensitive, and cost-effective detection. Here we describe an assay optimization process with a fully automated immunoassay for estrone which resulted in a LOD below 0.20 ng L⁻¹ and a LOQ below 1.40 ng L⁻¹. In contrast to common analytical methods such as GC-MS or HPLC-MS, the biosensor used requires no sample pre-treatment and pre-concentration. The very low validation parameters for estrone are the result of the continuous optimization of the immunoassay. The basis of our sensitive assay is the antibody with a high affinity constant towards estrone. During the optimization process, we reduced the amount of antibody per sample and improved the chip surface modification. Finally, this proceeding led to a calibration routine with an amount of antibody of only 3.0 ng per sample (sample volume: 1.0 mL). The reduction of the amount of antibody per sample results in better validation parameters (LOD, LOQ, and IC₅₀), but this reduction leads to the current device-related limitation of the River Analyser (RIANA).For some endocrine disrupting compounds, no effect levels (NOELs) in the lower nanogram per liter range are reported. This defines the challenge, which analytical methods have to compete with and our RIANA instrument with its improved sensitivity for the detection of a single hormone in the lower nanogram per liter range is a powerful tool in aquatic analytics in addition to the common analytical methods.     

The impact of LIMS design and functionality on laboratory quality achievements

 A laboratory information management system (LIMS) can make a major contribution to the quality and therefore to the efficiency and competitiveness of a laboratory. Since it can impact all aspects of a laboratory's organization it must be the key if not the principal player of the laboratory's quality system. It should support the laboratory in establishing, maintaining and applying quality procedures thereby enabling the laboratory to achieve its quality goals. As a tool, LIMS permits the laboratory to input and use its own know-how and experience to optimize the total organization (internal and external) and workflow of generated information. However, perceived "quality" in the context of an LIMS, can be viewed as being made up of different facets such as the security, reliability and accessibility of information as well as its turn around time and production cost. This paper reviews the role of a LIMS in the laboratory and the contribution that both system design and functionality can have on "building quality ". Received: 5 October 1998 · Accepted: 20 October 1998     

Information content of data and variables and types of weighting in least-squares regression methods

Algorithms are given for evaluating the relative amount of useful information related to a particular parameter which is carried by individual data points and intervals of the variables. The algorithms provide an efficient means of using the information contained in a set of data. Applications to the optimization of weighting in regression methods are described. Several informational and combined informational-statistical types of weighting are studied as a means of improving the accuracy and precision of the parameters obtained by non-linear regression.     

Improved quantification limits in chiral capillary electrochromatography by peak compression effects

The peak compression effect has been applied to improve quantification limits in chiral capillary electrochromatography (CEC). A stationary phase based on the chiral selector vancomycin (Chirobiotic V) was used for separations of the enantiomers of mianserin. By adding solvents with a low dielectric constant, e.g. 2-propanol or tetrahydrofuran, to the sample solution, peak compression could be induced. The plate numbers for the minor enantiomer increased from approximately 100,000 to 1.4-1.6 million plates/m, when the composition of the mobile phase was adjusted so that the analyte eluted within either one of two system zones originating from the sample solution. A 10-fold improvement in the quantification limit for the minor enantiomer was obtained compared to elution under non-focused conditions.     

Pattern-specific neural network design

We present evidence that the performance of the traditional fully connected Hopfield model can be dramatically improved by carefully selecting an information-specific connectivity structure, while the synaptic weights of the selected connections are the same as in the Hopfield model. Starting from a completely disconnected network we let genuine Hebbian synaptic connections grow, one by one, until a desired degree of stability is achieved. Neural pathways are thus fixed notbefore, butduring the learning phase.     

Hexagonal Ferrites from Melts and Aqueous Solutions,Magnetic Recording Materials

Owing to their particular crystallographic properties, ferrimagnetic hexagonal ferrites exhibit a far greater coercive force than the conventional magnetic pigments. They therefore appear to be suitable for use in magnetic information storage procedures, some of which are novel and are at the development stage. Thus, magnetic tapes of high coercive force containing barium ferrite could be used as master tapes for copying magnetic information or for producing forgery-proof magnetic cards, if magnetic heads having high-order write fields were successfully developed. Moreover, platelet-like ferrite pigments in which the preferred direction of magnetic orientation is perpendicular to the plane of the platelet are of great interest for perpendicular magnetic recording. In this progress report, the crystal structures, magnetic characteristics of hexagonal ferrites, and chemical processes for their production are discussed. In particular, reactions in salt melts or under hydrothermal conditions produce finely divided pigments whose particles have a pronounced hexagonal, plate-like habit, a narrow particle size distribution, and advantageous magnetic properties. The magnetic properties of the pigments crystallized from salt melts may be adjusted by cation exchange.     

Solutions of alkali soaps and water in fatty acids IX. The location of theL 2-phase in three-component systems of sodium soap — fatty acid — water,in view of the occurrence of acid soaps

Previous studies of the occurrence of acid soaps in systems containing a longchain sodium soap and the corresponding fatty acid, and the study of phase equilibria in the system sodium octanoate — octanoic acid — water, performed by our group at the beginning of the 1960s, show that the isotropic liquidL ₂-phase of the last mentioned system in its whole region of existence is situated in that part in which acid soaps occur. This provides an explanation for the fact that theL ₂-phase itself contains acid sodium octanoates in all regions. TheL ₂-phase has its origin in the water-free melt of fatty acid and neutral soap in which these components react with each other under the formation of an acid soap. When water is added to the system, this water-free acid soap is transformed into different hydrated acid soaps. In a large region of concentration, there is an extremely close relation between theL ₂-phase and the liquid-crystalline lamellarD-phase, which itself consists of hydrated acid soaps. At its outermost water-rich tip, theL ₂-phase is in equilibrium with theL ₁-phase of the system, just above the+LAC, that is, with the most dilute aqueous soap solution in which acid soap still may be formed in aqueous environment. Formation of acid soap is a fundamental requirement for the existence of this isotropic liquidL ₂-phase.