An approximate method of analysis of large deflections

Zusammenfassung Ein einfaches analytisches Näherungsverfahren zur Behandlung einer Klasse nichtlinearer Randwertaufgaben wird beschrieben und bei der Berechnung der grossen Biegeverformungen von schweren, dünnen Balken und Säulen angewandt. Das Wesen des Verfahrens beruht auf der Linearisierung (oder der Herabsetzung des Nichtlinearitätsgrades) der nichtlinearen Differentialgleichung mittels der Tschebyschewschen Polynome. Die Genauigkeit des Verfahrens beruht auf der Eigenschaft der Tschebyschewschen Entwicklungen, den absoluten Maximal-Fehler der polynomischen Annäherung an eine gegebene Funktion in einem vorgeschriebenen Intervall beinahe auf ein Mindestmass zu verringern.     

Synthesis of bis(tetramethylstibonium)tetracyclopentadienylstannate a novel type of organotin(II) compound

Reaction of dicyclopentadienyltin(II) with pentamethylantimony gives [Me₄Sb]₂⁺[(C₅H₅)₄Sn]^2?, the first example of an anionic organotin(II) species.     

The use of the mass spectrometer for the quantitative analyses of mixtures of amino acids

The quantitative analysis of a low vapor pressure unstable solid mixture of amino acids is possible by putting the solid mixture in a crucible which is then placed directly into the ionization chamber of a mass spectrometer. Relative sensitivities for the various acids in a mixture can be established by the proper use of a particular amino acid as an internal-calibrating standard. The success of the method depends upon: (1) the reproducibility of the mass spectra of the pure components, (2) the ideal vapor pressure behavior of the solid mixture, (3) the preparation of an intimate solid mixture by rapid freezing of the water solution of the acids with subsequent vacuum sublimation of the ice and ball-milling the dried mixture.     

Analysis of a multi-level time-sharing model

The multi-level time sharing algorithm is studied. Each new job joins the bottom level queue. After each quantum of service it goes to the next higher level until it has completed service. The server always selects the job at the head of the lowest level nonempty queue. A constant overhead is incurred for each quantum of service. Mean waiting time and mean system delay cost are better than those of the round robin model.     

Hyperon magnetic moments and total cross sections clues to QCD or flavor dependence

The new data on both total cross sections and magnetic moments are simply described by beginning with the additive quark model in an SU(3) limit where all quarks behave like strange quarks and breaking both additivity and SU(3) simultaneously with an additional non-additive mechanism which affects only non-strange quark contributions. The suggestion that strange quarks behave more simply than nonstrange may provide clues to underlying structure or dynamics. Small discrepancies in the Ξ moments are analyzed and shown to provide serious difficulties for most models if they are statistically significant.     

Nuclear magnetic resonance studies of the phosphorus(v) pesticides : A rapid determination of the isomer ratio of systox

The integration circuit of the Varian A-60 nuclear magnetic resonance spectrometer is used in conjunction with vapor phase chromatography, to develop a rapid analysis technique for the determination of isomer ratios in technical Systox-Sulfotepp mixtures. The complete analysis requires less than 0.1 g of sample and only 15 min. The isomer ratio in the sample may be determined to an accuracy of ±1.5% and the undamaged sample may be recovered.     

Novel heteroaromatic silanes in the gas phase

The appearance of intense peaks, due to the (P—30)²⁺ ions, in the mass spectra of 8-trimethylsiloxyquinoline, 2-methyl-8-trimethylsiloxyquinoline, 2-trimethylsiloxymethylpyridine and 2-trimethylsiloxymethyl-6-methylpyridine suggests that these ions have considerable heteroaromatic character.