Bending and stretching unit vector fields in Euclidean and hyperbolic 3-space

We discuss Morse inequalities for homotopic critical maps of the energy functional with a potential term. For a generic potential this gives a lower bound on the number of homotopic critical maps in terms of the Betti numbers of the moduli space of harmonic maps. Other applications include sharp existence results for maps with prescribed tension field and pseudo-harmonic maps. Our hypotheses are that the domain and target manifolds are closed and the latter has non-positive sectional curvature.      

F?llungsmethoden zur Bestimmung des Gerbstoffs

Ohne Zusammenfassung     

Scheme for the microchemical separation of some toxicologically important alkaloids

Summary A scheme for the successful separation and identification of milligram quantities of twenty of the most important narcotic alkaloids has been presented. The alkaloids studied are those which are most commonly employed in general pharmacology and hence are most frequently met with. The scheme has been found useful when the total quantity of the alkaloids in 1 milliliter of aqueous solution ranges from 0,5 to 3 milligrams and not more than three of the bases are present at a time. If only one alkaloid is present, still less than one half milligram can be isolated and definitely identified. In addition, it has been found that in the case of certain alkaloids, e. g. morphine, it is possible to separate less than 0,5 milligram from a mixture of the bases studied.

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Zusammenfassung Es wird ein Verfahren für die Trennung und den anschließenden Nachweis von Milligrammengen von zwanzig der wichtigsten narkotischen Alkaloide beschrieben. Die berücksichtigten Alkaloide gehören zu denen, die in der Pharmakologie allgemein verwendet werden und denen man daher auch häufig begegnet. Der Trennungsgang hat sich bewährt, wenn die Gesamtmenge der in 1 Kubikzentimeter wäßriger Lösung enthaltenen Alkaloide zwischen 0,5 und 3 mg beträgt und im jeweiligen Falle nicht mehr als drei der berücksichtigten Basen gleichzeitig zugegen sind. Wenn nur ein einziges Alkaloid anwesend ist, so können weitaus geringere Mengen davon isoliert und einwandfrei nachgewiesen werden. Außerdem genügen von gewissen Alkaloiden, wie z. B. Morphin, weit kleinere Mengen als 0,5 mg, um die Abtrennung aus Alkaloidgemischen und den Nachweis zu gestatten.

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Résumé (L) Les auteurs proposent une méthode de séparation et d'identification de vingt des plus importants des alcaloides narcotiques, sur des quantités de l'ordre du milligramme. Les alcaloides envisagés sont les plus employés en pharmacologie et par conséquent aussi ceux que l'on rencontre le plus fréquemment.La méthode de separation s'est révélée efficace quand la quantité totale d'alcaloide contenue dans un centimètre cube de solution aqueuse est comprise entre 0,5 et 3 mg, alors que simultanément n'existent en solution tout au plus que trois des bases envisagées. Dans le cas où un seul des alcaloides existe en solution, des quantités beaucoup plus petites de celui-ci peuvent encore être mises en évidence. En outre, pour certains alcaloides, comme la morphine, des quantités très inférieures à 0,5 mg permettent encore son extraction du mélange d'alcaloides et sa caractérisation ultérieure.

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The work herein reported represents a portion of the work presented by Mr.Wood as his dissertation in partial fulfillment of the requirements for the degree of Doctor of Philosophy at the Polytechnic Institute of Brooklyn.     

Chemische Studien zur Holzkonservierung

Ohne Zusammenfassung     

On-chip pulsed terahertz systems and their applications

The generation and detection of guided wave terahertz (THz) transients in microstrip transmission line systems is demonstrated at both room and cryogenic (∼ 4 K) temperatures using thin film low-temperature-grown GaAs (LT-GaAs) switches, excited by a 100 fs, 80 MHz repetition rate pulsed Ti:Sapphire laser. The characterisation of passive filter elements formed in the microstrip line is reported, together with their response to the application of dielectric loads of varying thickness at room temperature.     

Using carbon nanotubes to detect polymer transitions

Raman spectral shifts of single‐wall carbon nanotubes embedded in polymer systems were used to measure transitions in polymers. Glass‐transition temperatures and secondary transitions were observed, and Raman spectroscopic data were compared with dynamic mechanical tests for a thermosetting and a thermoplastic polymer. The data confirm that the Raman spectral response of carbon nanotubes embedded in polymers is sensitive to polymer transitions. © 2001 John Wiley & Sons, Inc. J Polym Sci Part B: Polym Phys 39: 1492–1495, 2001     

Syntheses of new 'large core' discogens based on the triphenylene,azatriphenylene and hexabenztrinaphthylene nuclei

We have synthesized new discogens based on polyphenylated triphenylene, polyphenylated azatriphenylene and hexabenztrinaphthylene. A procedure for the extension of the aromatic core by Suzuki coupling is described, which minimizes competitive reductive dehalogenation.     

Stress evolution to steady state in ion bombardment of silicon

Low temperature ion bombardment of initially crystalline, defect-free silicon with 700 eV ion beam energy creates a highly-damaged stressed layer a few nanometers thick on the surface. An apparent steady state in structure is achieved at a fluence of 2 × 10¹⁴–3 × 10¹⁴ ions/cm². In this work, the stresses are computed using the interatomic force definition of stress. The stress evolution is studied as a function of argon implantation into the target. Stress per implanted argon atom is observed to reach a nearly constant value between 20 MPa and 25 MPa at a fluence of 1.2 × 10¹⁴ ions/cm².