IR-spektroskopische Untersuchungen am Poly?thylen. 2. Mitt. Die Charakterisierung der spezifischen Typen von Alkylverzweigungen in ?thylen-Polymeren und Copolymeren geringer Verzweigung

Ohne Zusammenfassung     

Miller–Urey Revisited: When Lightning Strikes the Earth

A discharge is arced to different solutions containing the simple molecular species water, methanol, and ammonia. We show that the impact of the discharge at the discharge-solution interface produces a range of organic molecules, including amino acids and polymers containing carboxylate, amine, imine, and cyano groups. The classic Miller-Urey experiment, of which there are hundreds of variations, changing parameters such as gas composition, pressures, and voltage have been tested, involves the production of simple amino acids and other species in the gas phase in an arc discharge. This works emphasis is the production of various chemical species at a discharge-liquid interface. The analysis of the product is conducted by IR, UV–VIS, LC–MS and MALDI–MS. As a laboratory exercise or a demonstration, this simple derivation of the Miller-Urey experiment can be used in a variety of teaching settings, from high school through advanced undergraduate research classes to demonstrate the basic hypothesis of how life on Earth may have started.     

The Milnor–Totaro Theorem for Space Polygons

If denotes the curvature and the torsion of a closed, generic, and oriented polygonal space curve X in , then we show that _X (² + ²) ds = _X ds + _X | | ds > 4 if is positive. We also show that _X (² + ²) ds 2n if no four consecutive vertices lie in a plane and X has linking number n with a straight line. These extend theorems of Milnor and Totaro.     

Covalent Functionalization of HiPco Single‐Walled Carbon Nanotubes: Differences in the Oxidizing Action of H2SO4 and HNO3 during a Soft Oxidation Process

The results of a study on the evolution of HiPco single‐walled carbon nanotubes during the oxidizing action of H₂SO₄ and HNO₃ are presented. The process conditions used have been chosen so as to avoid any significant damage to the nanotube structure. The type and level of functionalization, the location of the grafted functions on the surface of the nanotube and the changes in morphological characteristics of the samples were examined by using a wide and complementary range of analytical techniques. We propose an explanation for the differences in the oxidizing action of sulfuric and nitric acids. The combined results allow us to suggest possible reaction mechanisms that occur on the surface of the nanotube.