Studies of the out-of-plane emission of pions in symmetric heavy-ion collisions

Triple differential cross-sections of midrapidity pions from ²⁰⁹Bi+²⁰⁹Bi collisions were measured with the Kaon Spectrometer at SIS at incident energies of 400, 700 and 1000 AMeV. The azimuthal emission pattern of the pions has been investigated in dependence of beam energy and impact parameter. An enhanced emission of pions perpendicular to the reaction plane is observed. The strength of the anisotropy increases with beam energy and pion transverse momentum. In contrast to the nucleons the anisotropy varies only little with the impact parameter. No difference in the behaviour of positive and negative pions is observed.     

Thermal decomposition of energetic materials. 45. Fast thermolysis patterns of energetic oxamides

Fast thermal decomposition (dT/dt=70-80°C sec^–1) of four energetic oxamides [N,N-bis(2-nitratoethyl) oxamide, N,N-bis(3-nitratopropyl)oxamide, N,N-bis(2-nitratopropyl)oxamide, and N,N-bis(2-azidoethyl)oxamide] in Ar is described by FTIR/temperature profiling. The product sequence and temperatures are used to analyze how the alkyl chain length, the position of the nitrate ester group, and the nature of the energetic group affect the thermolysis process. The crystal structure of N,N-bis(3-nitratopropyl)oxamide was determined: monoclinic,P2₁/c,a=5.125(2),b=6.906(2),c=18.441(8) Å,=94.91(3)°,V=650.3(4) ų,Z=2,D=1.502 g cm^–3,R(F)=0.036,R(wF)=0.044.     

Comparison of Young's modulus and specific heat anomalies at the magnetic transition in α′-NaV2O5

We have measured Young's modulus (using a vibrating reed technique) and the specific heat (using ac calorimetry) on the same crystals of α′-NaV₂O₅ at its T_c=34 K magnetic phase transition. Both properties exhibit large, unsymmetrical, and sample-dependent anomalies. While the specific heat results suggest tricritical behavior of the transition, large fluctuation effects are observed in the modulus above T_c. Fits of the modulus in terms of the specific heat, entropy, and free energy suggest that fluctuations are strongly stress- and sample-dependent.     

Phosphoramidites as Synthons for Polynucleotide Synthesis

Abstract

Methods for the rapid synthesis of DNA and RNA are described. The procedures involve using nucleoside phosphoramidites as synthons and silica as a polymeric support. Additionally, a novel reaction involving nucleoside O-alkyl methylphosphonothioates is described.     

Use of computerized pattern recognition in the study of the cuticular hydrocarbons of imported fire ants. II. Comparison of the cuticular hydrocarbon patterns between different colonies of Solenopsis richteri

Gas chromatography (GC) data obtained from the cuticular hydrocarbons of the black imported fire ants are treated by methods of pattern recognition. Based on a recently described sample preparation procedure, GC data are normalized to eliminate slight variations in chromatographic conditions, and converted to the proper format for discriminant analysis by computer. The results of several methods of data treatment and display are discussed, based on the chemometrics system package, ARTHUR.     

Evaluating environmental quality management programmes in which dischargers are grouped

A method is presented for evaluating management programmes in which the dischargers are divided into groups. Analogous non-linear mathematical formulations are presented for direct regulation and effluent charge programmes, and a non-linear branch-and-bound solution procedure is described. A detailed algorithm is described for the effluent charge case; it is shown to be very practical in an application to data for the Delaware estuary.