Kohlenhydrate

Ohne Zusammenfassung     

Pflanzenchemie

Analytical and Bioanalytical Chemistry -     

N = 1 supergravity in the light-cone gauge

N = 1 supergravity is studied in a light-cone gauge. The non-linear transformations and the hamiltonian are constructed to order K in the coupling constant as a realization of the super-Poicaré algebra. The only input except the algebraic structure is the helicity content ($\text{±2, ±}\text{3}\text{2}$) and the dimensionality of the coupling constant.     

Rotational bands and particle-hole excitations at very high spin

A method of calculating high-spin states of nuclei within the cranked Nilsson-Strutinsky framework is presented and discussed in some detail. With this method, various high-spin features of nuclei are studied, such as shape coexistence, shape changes, band crossings and band terminations. Nuclei with different mass numbers such as ¹⁰⁶Pd, ¹¹⁸Te, ¹⁵⁸Yb and ¹⁸⁷Au are used to exemplify the formalism. Comparisons are made with observed discrete high-spin states in ^{160, 165, 168}Yb, ¹⁶⁸Hf, ¹⁷¹Ta and ¹³⁰Ce.     

Temperature and concentration measurements in acetylene-nitrogen mixtures in the range 300–600 K using dual-broadband rotational CARS

Pure rotational coherent anti-Stokes Raman scattering (CARS) experiments have been performed in acetylene for temperatures ranging from 294 to 582 K, and in mixtures of acetylene and nitrogen in the mole fraction range of 0.06–0.32 for acetylene at room temperature. The experimental spectra are evaluated by a least-square fitting to libraries of theoretically calculated spectra using two different Raman linewidth models, one with and one without dependence on the rotational quantum number J. It is found that a J-dependent model is favourable, both regarding temperature measurements in pure acetylene, and simultaneous acetylene concentration and temperature measurements in different mixtures of acetylene and nitrogen. For the temperature measurements performed in pure acetylene the temperature inaccuracy is generally less than 2% when the J-dependent model for the Raman linewidths is used. It is found that fitting the value of the non-resonant susceptibility significantly improves the quality of the spectral fits and is a requirement for high temperature accuracy with the present model. The evaluated concentrations show a maximum error of 13% on a relative scale. Potential sources of systematical errors both regarding measured temperatures and acetylene concentrations are discussed. Received: 8 June 1999 / Revised version: 3 Spetember 1999 / Published online: 3 November 1999     

Parton showers in leptoproduction events

We present a model that includes the production of arbitrarily many jets in lepton-hadron events, using the leading log formalism for parton shower evolution. The main problem encountered here, which has not previously been illuminated by studies ofe ⁺ e ^? annihilation or Drell-Yan/Z ⁰/W ^± production, is the choice of kinematics in the space-like shower evolution. In our preferred solution, the standard definition of Bjorkenx is preserved during the construction of initial and final state showers—a nontrivial constraint. The resulting model is described in detail, including some first investigations of its properties.     

Soot-visualization strategies using laser techniques

Strategies for spatially resolved soot volume-fraction measurements have been investigated in sooting laboratory flames with known soot characteristics. Two techniques were compared: Laser-Induced Fluorescence in C₂ from Laser-Vaporized Soot (LIF(C₂)LVS), and Laser-Induced Incandescence of soot (LII). The LII signal is the increased temperature radiation from soot particles which have been heated to temperatures of several thousand degrees as a consequence of absorption of laser radiation. The LIF(C₂)LVS technique is based on the production of C₂ radicals from laser-vaporized soot which occurs for laser intensities ≥10⁷ W/cm². A laser wavelength is chosen such that besides vaporizizng the soot, it also excites the C₂ radicals, and the subsequent C₂ fluorescence signal is detected. The signals from both techniques showed good correlation with soot volume fractions in the studied flame. The dependence of the signals on experimental parameters was studied, and the influence of interfering radiation, such as background flame luminosity and fluorescence from polyaromatic hydrocarbons, on studied signals was established. The potential of the two techniques for imaging of soot volume fractions in laboratory flames was demonstrated. Advantages and disadvantages of the studied techniques are discussed.     

Finding the 3-gluon vertex from 4-jet events ine + e − annihilation

General properties of single transversee ^± beam polarization asymmetries (cos ? or sin ? azimuthal distributions and their forward-backward asymmetries) are established. These asymmetries are genuine ways of analyzing the structure of chirality violating amplitudes at high energy. Several examples of chirality violating processes are considered and their asymmetries computed. Constraints due tog _e ?2,d _e andm _e are obtained in the form of sum rules and their physical consequences are discussed.     

Loss of alignment gain in the πh 9/2[541 1/2−] ⊗ (νi 13/2)2 band in 167Tm and neighbouring odd-Z N = 98 nuclei

Theπh_9/2[541 1/2^?] band in ¹⁶⁷Tm has been studied through the ¹²⁴Sn(⁴⁸Ca, p4n)¹⁶⁷Tm reaction at E _beam = 210 MeV. The favoured signature of the πh_9/2[541 1/2^?] band is observed to spin 61/2h?. A remarkable small gain in aligned angular momentum at the AB-band crossing has been found. The crossing frequency and the gain in aligned angular momentum for ¹⁶⁷Tm are compared with data for the N = 98 isotones of Lu, Ta and Re, and contrasted with Cranked Shell Model predictions, based on frequency diabatic configurations. Large deviations are found for the gain in aligned angular momentum.     

Competition between (h11/2)2 proton and neutron excitations around128Ba: Coexistence of near prolate and near oblate shapes at high spin

Recent cranked shell model calculations give a possible explanation for the occurrence of two S-bands in Ba-nuclei.