On some weight functions admitting (0, 2) quadrature formulae with a high algebraic degree of precision

The purpose of this paper is to find a class of weight functions μ for which there exist quadrature formulae of the form (1) $$\int_{ - 1}^1 {\mu (x) f(x) dx \approx \sum\limits_{k = 1}^n {(a_k f(x_k ) + b_k f''(x_k ))} }$$ , which are precise for every polynomial of degree 2n.     

比利时UGINE ＆ ALZ新建不锈钢厂投产一年的运行情况

2000年11月奥钢联从比利时ALZ获得将其不锈钢产能提高1倍、达到120万t／a的合同。介绍了相关设备及投产一年以来的运行结果。     

Mobile commerce and device specific perceived risk

This study examines the role of perceived risk and access device type on consumers’ on-line purchase decisions. We use a two-step hurdle approach to estimate consumer behavior. In the first step, the decision of whether to engage in eCommerce is estimated and in the second step, how many orders to place is estimated. We use a large multi-year survey sample of households from Canada’s national statistical agency—Statistics Canada. The sample size is such that we are able to conduct sub-sample analysis of PC-only users, mobile-only users, and other-users. We show that online security and price significantly influence mobile eCommerce. We also show that there is a statistically significant difference in the intensity of eCommerce engagement across device type and consumer risk type (high/low). One of our main findings is that perceived risk affects purchase decisions for mobile users more than PC users, however additional comparisons are carried out with our analysis.     

A new type of gas sensor based on the thermovoltaic effect in zinc oxide inhomogeneously doped with mixed-valence impurities

We propose a new type of potentiometric gas sensor operating on the basis of the thermovoltaic effect in uniformly heated (without temperature gradients) ZnO/ZnO–Fe sandwich structures obtained by the sol–gel method. It is established that a significant contribution to the gas responsivity of sensors is related to the thickness of the upper doped layer of the structure.     

Polyethylene/Polycaprolactone Nanocomposite Films for Food Packaging Modified with Magnetite and Casein: Oxygen Barrier,Mechanical, and Thermal Properties

Polyethylene (PE) was modified and prepared as double-layer polyethylene/polycaprolactone (PE/PCL) film. Magnetite and casein were added to the PCL-coating film to improve barrier properties and prevent destruction of basic structure of primary polymer PE. Significant improvements were observed with regards to mechanical (tensile strength, elongation at break) and thermal properties, while barrier (O₂ permeability) properties were slightly improved. Overall migration values into acetic acid were lower (from 1 to 4.6 mg/dm²) than the upper limit set by the legislation. Specific migration of iron in PE/PCL-Fe samples is also below (µg/L) specific migration limit value set by the legislation (mg/kg).     

Elimination kinetic model for organic chemicals in earthworms

Mechanistic understanding of bioaccumulation in different organisms and environments should take into account the influence of organism and chemical depending factors on the uptake and elimination kinetics of chemicals. Lipophilicity, metabolism, sorption (bioavailability) and biodegradation of chemicals are among the important factors that may significantly affect the bioaccumulation process in soil organisms. This study attempts to model elimination kinetics of organic chemicals in earthworms by accounting for the effects of both chemical and biological properties, including metabolism. The modeling approach that has been developed is based on the concept for simulating metabolism used in the BCF base-line model developed for predicting bioaccumulation in fish. Metabolism was explicitly accounted for by making use of the TIMES engine for simulation of metabolism and a set of principal transformations. Kinetic characteristics of transformations were estimated on the basis of observed kinetics data for the elimination of organic chemicals from earthworms.     

Formation of mesoglobules in aqueous media from thermo-sensitive poly(ethoxytriethyleneglycol acrylate)

A series of six poly(ethoxytriethyleneglycol acrylate) (PETEGA) homopolymers were synthesized by atom transfer radical polymerization, reversible addition-fragmentation transfer polymerization, and anionic polymerization in order to cover a molecular weight range from 7,000 to 40,000 Da. The polymers exhibited a lower critical solution temperature (LCST) behavior in water, which was observed by the occurrence of a cloud point (CP) at around 35 °C. The transmittance of visible light versus temperature dependence overlapped during the cooling and the heating cycles, showing almost a complete lack of hysteresis. Moreover, instead of the occurrence of an uncontrolled macroscopic phase separation, stable colloidal aggregates (mesoglobules) of narrow distribution in particle size were formed in water at temperatures above the LCST of PETEGA at 1 g L⁻¹ solutions. The dimensions of the mesoglobules ranged from 91 to 235 nm, and particle size was not influenced by the molecular weight of PETEGA. Temperature changes caused considerable variations of the mesoglobules dimensions, which were smaller at higher temperatures. The addition of an anionic surfactant simultaneously increased the CP values by 4–6 °C and lowered the dimensions of the mesoglobules.     

Comparison of the fatty acids of the tunicateBotryllus schlosseri from the Black Sea with two associated bacterial strains

The fatty acid composition of the tunicateBotryllus schlosseri and of two bacterial strains found within the tunicate, namelyVibrio parahaemolyticus and of an associated but previously unreported gram positive cocci were studied. The polyunsaturated fatty acids 6,9,12-octadecatrienoic acid, 5,8,11,14,17-eicosapentaenoic acid, and 4,7,10,13,16,19-docosahexaenoic acid were particularly abundant inB. schlosseri and were not detected in the two bacterial strains found in the tunicate. Theiso/anteiso pair, 13-methyltetradecanoic acid and 12-methyltetradecanoic acid, were the principal fatty acids in the gram positive cocci, and the 9- and 11-hexadecenoic acids were particulary abundant inV. parahaemolyticus. The diunsaturated fatty acid 9,12-octadecadienoic acid was also shown to be present inV. parahaemolyticus. The fatty acid composition of a third bacterial strain, characterized as either aPseudomonas or anAlteromonas species, and shown to be present only in the sea water from the Black Sea and not inB. schlosseri, is also reported. This is the first investigation on fatty acids from Black Sea bacteria.