Bestimmung von Wasser in Dichloressigsäure

Water concentrations in dichloroacetic acid in the range of 0<C <1 % (C = percent by weight) can be determined directly by photometry at 1425 nm. The absorbance A at this maximum is described by the function A=1.267×C^0.93 (cell path d=5 cm, correlation coefficient r=0.997). The variation coefficient for water concentrations of ≈0.06% was found to be V=6.5%.     

Organometallphosphin-substituierte übergangsmetallkomplexe XVII. Tetracarbonyl-di(organometallphosphin)-chrom-, -molybdän- und -wolfram-komplexe

Bicyclo[2.2.1]-2,5-heptadiene complexes of transition metal carbonyls have been treated with organometallic phosphines, to give the disubstituted compounds [(R₃M′)₃P]₂M(CO)₄ [R = CH₃; M′ = Ge, Sn; M = Cr, Mo, W] by exchange of ligands. The chemical and spectroscopic properties of the new compounds are reported.     

Anharmonicity in rotational and vibrational excitation of H2 by Li+ collisions

Integral cross sections for pure rotational and vibrational-rotational excitation of H₂(X¹Σ⁺_g) by Li⁺(¹S) impact are computed by close-coupling methods at 0.2, 0.6, and 1.2 eV in the c.m. system using vibrational functions that are numerical solutions of the one-dimensional radial Schrödinger equation for harmonic, Morse, and adiabatically corrected Kolos-Wolniewicz (KW) potential functions. Comparison of results employing KW and Morse functions shows excellent agreement for all transitions studied. Findings using harmonic oscillator functions, however, differ noticeably from KW and Morse values for vibrational (0 → 1) and very large rotational (Δj = 10) transitions, but are satisfactory for lower order (0 → 2, 4, 6, 8) rotational transitions.     

Beiträge zur Chemie der Silicium—Stickstoff-Verbindungen, 16. Mitt.: N-Silyl-carbonamide und N-Silyl-carbamidsäureester

Zusammenfassung Die durch direkte Silylierung von Carbonamidgruppen mit Halogensilanen nicht zugänglichen Verbindungen der Gruppierung R-CONHSiR₃ konnten durch Umsetzung von Säureamiden oder Säurechloriden mit Hexamethyldisilazan gewonnen werden. So wurden Derivate mit R=CH₃, C₂H₅, C₆H₅, CONHSiR₃ , OCH₃, OC₂H₅, OCH(CH₃)₂; R=CH₃ (vgl. Tab. 1) dargestellt und in ihren physikalischen und chemischen Eigenschaften näher studiert.Herrn Prof. Dr.A. Zinke zum 70. Geburtstag gewidmet.15. Mitt.:U. Wannagat undH. Kuckertz, Angew. Chem.74, 117 (1962).Auszug aus der DissertationJ. Pump, Techn. Hochsch. Aachen 1962.     

Eine Methode zur Bestimmung partieller spezifischer Volumen in kleinen Flüssigkeitsmengen

Zusammenfassung Eine Apparatur zur Bestimmung kleiner Dichtedifferenzen wird beschrieben, die einen mit einem kleinen Magneten versehenen Schwimmer enth?lt, der durch ein in me?barer Weise ver?nderliches magnetisches Feld in der Flüssigkeit zum Schweben gebracht wird. Zur Messung werden nur 10 ml L?sungsmittel und 10 ml L?sung ben?tigt. Die Empfindlichkeit betr?gt etwa 2 · 10⁻⁶ g/cm³ (2 Stellen der sechsten Dezimale der Dichte). Die zum Vergleich bestimmten partiellen spezifischen Volumen von Rinder-Serumalbumin und Chymotrypsinogen ergaben für das erstere im Konzentrationsbereich zwischen 0,04 und 0,65% einen Mittelwert von 0,733₅ (20,0° C) und für das letztere einen Wert von 0,720 (21,6° C).     

Synthesis of β-Glucuronides of Estradiol,Ethynylestradiol and Estrone

ABSTRACT

Improved syntheses for the 3-β-D-glucuronides of the steroidal sex hormones 17β-estradiol, 17α-ethynylestradiol and estrone are reported employing boron trifluoride diethyl etherate catalysis with tetraacetylated glucuronic acid or the corresponding imidate.     

Compactly Supported Tight Affine Frames with Integer Dilations and Maximum Vanishing Moments

When a cardinal B-spline of order greater than 1 is used as the scaling function to generate a multiresolution approximation of L ²=L ²(R) with dilation integer factor M2, the standard matrix extension approach for constructing compactly supported tight frames has the limitation that at least one of the tight frame generators does not annihilate any polynomial except the constant. The notion of vanishing moment recovery (VMR) was introduced in our earlier work (and independently by Daubechies et al.) for dilation M=2 to increase the order of vanishing moments. This present paper extends the tight frame results in the above mentioned papers from dilation M=2 to arbitrary integer M2 for any compactly supported M-dilation scaling functions. It is shown, in particular, that M compactly supported tight frame generators suffice, but not M–1 in general. A complete characterization of the M-dilation polynomial symbol is derived for the existence of M–1 such frame generators. Linear spline examples are given for M=3,4 to demonstrate our constructive approach.     

A note to the paper “An efficient algorithm for linear programming” of V Ch Venkaiah

In Venkaiah [1] an algorithm for solving linear optimization problems based on the idea of the projective algorithm of Karmarkar, is proposed. The essential simplification in the new algorithm is the use of a fixed projection operator. In this way the algorithm requires onlyO(n ² ) operations to obtain a sufficient exact solution. In this note it is shown that in some special cases the algorithm of Venkaiah yields a feasible solution that is far from the optimal one.