多边形和多面体顶点法矢的数值估计

证明了两个定量，定理1揭示了三点多边的外接圆在中点处的法矢与两个边界法矢的关系；定理2揭示了四面体外接球面在中点处的法矢与三个相邻三角平面的法矢量的关系，给出了一个判别二维多维边形和三维多面体顶点法矢计算方法优劣的准则，在此基础上，提出一种用于估计三维多面体顶部的法矢量的计算方法，两个例子说明文中给出的准则和算法的合理性和实用性。     

FLASH correlation: a new method for 3-D ultrasound tissue motion tracking and blood velocity estimation

We report a new method for tracking tissue motion and blood flow in three dimensions (3-D) using successive volumetric ultrasound scans. The method is based on combining the concepts of feature tracking and 3-D correlation search to achieve a compromise between accuracy and computational efficiency. This paper introduces the new method and the experimental setup used for its evaluation in a tissue-mimicking material. Results are presented demonstrating that the new method has both satisfactory tracking performance and the potential for practical real-time implementation.     

Die Sauerstoffaktivität im System Eisen-Sauerstoff und ihre Beeinflussung durch Zusatzelemente bei Temperaturen der Stahlherstellung

Im Schrifttum bisher veröffentlichte Wirkungsparameter. Einfluß von Chrom, Antimon, Zinn, Vanadin und Wolfram auf die Sauerstoffaktivität. Abhängigkeit der Wirkungsparameter von der Ordnungszahl.     

Butadien-Polymerisation mit Alfin-Katalysatoren

The course of the butadiene polymerization with Alfin-catalysts is investigated. During the beginning of the polymerization high molecular weight polymers are formed. The addition of n-donors yields lower molecular weight polymers with, at times, altered structures. Triphenylphosphine reduces the molecular weight without affecting the structure. The addition of nickel compounds to Alfin-catalysts does not bring about an increase of the cis-content of the polymers. The rate of the butadiene-polymerisation with unmodified Alfin-catalysts is therefore considerably higher than that with nickel containing Ziegler catalysts.     

Gewinnung molekulareinheitlicher N-Propionyl-oligo-ε-aminocapronsäurepropylamide aus Oligokondensaten durch Gelpermeationschromatographie

N-propionyl-oligo-ε-aminocaproic-acid-propylamides have been prepared by transamidation of caprolactam with propionic acid propylamide. The oligocondensate contains no cyclic compounds, and is nearly free from linear amides with terminal amino or carboxy groups. Variations in the conditions of transamidation change the distribution of chain length. The oligocondensates are separated into individual compounds by gelpermeation chromatography using Sephadex LH-20 and phenol/ethanol/water (1:2.6:1.6 v/v) as eluant. The oligoamides have been isolated up to the pentadecamer. Sufficient amounts of material for physico-chemical measurements are easily obtained by this procedure.     

Der einfluß von tensiden auf die superkontraktion und das differentialkalorimetrische verhalten von keratinfasern

Supercontraction and DTA-measurements of Corriedale-wool in solutions of anion- and kation-active detergents were carried out at various pH. The temperature T_s and the amount of the fibre shrinkage were lowered at pH 7 by the detergents especially in dodecylamine-hydrochlorid (Dah) solutions. The DTA peak in Dah-solutions at pH 7 is broadened to high extent and the heat of transition is decreased drastically. At low pH-values - e. g. 2,5 - the DTA peak in Dah-solutions is unchanged in respective to that in pure water. In contrast the peak in acid solutions of sodium dodecylsulphate (Nds) has disappeared completely because the transition process has lost its cooparative character. This behaviour can be explained by the adsorption of the anion-active detergent caused by the protonated basic groups and the splitting of salt-bridges in the acid medium. In this way the hydrophobic interactions stabilizing the fibre structure are weakened and therefore the order-disorder transition begins already at low temperatures and takes place in a wide range.     

Synthese von Cystinpeptiden mit Hilfe der Festkörpermethode von Merrifield

The problem of sulfur protection in peptide chemistry can be circumvented by synthesis of symmetrical cystine peptides. Such peptides are available also by the MERRIFIELD method as follows: Coupling of excessive bis-tert.-butyloxycarbonyl-cystine with an aminoacyl resin leads to the formation of resin bound symmetrical and mixed disulfides. After reduction with a large excess of thiophenol the unreacted cystine-halves are washed out and the disulfide bridges are regenerated by subsequent oxidation with air in the presence of iron (III)-sulfate in dimethylsulfoxide/methylene chloride, or with a small excess of 2,2′-dipyridyldisulfide forming the desired resin bound symmetrical cystine peptide. However, and elongation of this peptide without side reactions is only possible, if the cystine residue is separated from the binding site on the resin by more than one amino acid residue.