Mononitration of durene

Reaction conditions under which the nitration of durene give predominantly, and in high yield, mononitrodurene (I), rather than dinitrodurene were found. The nitrating agent was No2+RF6-. Nitration with nitrosulfuric acid also gave mononitrodurene; however, byproducts such as 2.3.5.6-Me4C6HCH2C6H2Me3-2,4,5, were also formed. The NO2 PF6- gave an intermediate additional compound with durene. The reaction carried out with 3.6-dideuterodurene in D2O shows no isotope effect

Simulations of a Scintillator Compton Gamma Imager for Safety and Security

We are designing an all-scintillator Compton gamma imager for use in security investigations and remediation actions involving radioactive threat material. To satisfy requirements for a rugged and portable instrument, we have chosen solid scintillator for the active volumes of both the scatter and absorber detectors. Using the BEAMnrc/EGSnrc Monte Carlo simulation package, we have constructed models using four different materials for the scatter detector: LaBr_3, NaI, CaF_2 and PVT. We have compared the detector performances using angular resolution, efficiency, and image resolution. We find that while PVT provides worse performance than that of the detectors based entirely on inorganic scintillators, all of the materials investigated for the scatter detector have the potential to provide performance adequate for our purposes.Comment: Revised text and figures, Presented at SORMA West 2008, Published in IEEE Transactions on Nuclear Scienc

Evidence For An Iminium Cation Intermediate And Its Non‐Oxidative Decarboxylation In A Cerium (IV)‐Mediated Oxidative Decarboxylation. Preliminary Communication

Evidence is provided for the occurrence of a non‐oxidative decarboxylation in an iminium cation intermediate which is produced in an oxidative decarboxylation induced by cerium (IV). Copyright © 1980 Verlag GmbH & Co. KGaA, Weinhei

Telecommunications systems design techniques handbook

Handbook presents design and analysis of tracking, telemetry, and command functions utilized in these systems with particular emphasis on deep-space telecommunications. Antenna requirements are also discussed. Handbook provides number of tables outlining various performance criteria. Block diagrams and performance charts are also presented

Utilization of Soft-rot Cavity Orientation for the Determination of Microfibril Angle. Part I

These studies utilize the decay cavities formed by the soft-rot fungus, Phialocephala dimorphospora, to determine the orientation of the cellulose fibrils in the cell wall. In this study, the microfibril angle was determined utilizing three methods: X-ray diffraction (T method), iodine staining, and orientation of the soft-rot cavities. The results demonstrate good agreement between the three techniques and verify that the decay cavities are formed in a direction parallel to the cellulose microfibrils and therefore can be used to determine the orientation of the cellulose microfibrils. One advantage of the soft-rot method over the X-ray method is the ability to measure angles of any size, including those of juvenile wood

Variation of Microfibril Angle Within Individual Tracheids

Utilizing the orientation of soft-rot cavities, microfibril angles were measured in individual tracheids (pulped fibers) and thin sections of southern pine in order to determine the extent of variation. Within individual tracheids of southern pine, microfibril angles were consistent along the length of a tracheid and when measured between bordered pits. Microfibril angles were highly variable on the radial walls containing bordered pits. Microfibril angles approached 90° around bordered pits, but the angles on the walls opposite the bordered pits were consistent with the average angle along the length of the tracheid. Variation (standard deviation) was less in latewood tracheids than in earlywood tracheids. Within individual tracheids, there was no correlation between microfibril angle and tracheid width. Across an annual ring of southern pine, microfibril angle gradually decreased through the earlywood and became much smaller in the latewood

Creation and manipulation of Feshbach resonances with radio-frequency radiation

We present a simple technique for studying collisions of ultracold atoms in the presence of a magnetic field and radio-frequency radiation (rf). Resonant control of scattering properties can be achieved by using rf to couple a colliding pair of atoms to a bound state. We show, using the example of 6Li, that in some ranges of rf frequency and magnetic field this can be done without giving rise to losses. We also show that halo molecules of large spatial extent require much less rf power than deeply bound states. Another way to exert resonant control is with a set of rf-coupled bound states, linked to the colliding pair through the molecular interactions that give rise to magnetically tunable Feshbach resonances. This was recently demonstrated for 87Rb [Kaufman et al., Phys. Rev. A 80:050701(R), 2009]. We examine the underlying atomic and molecular physics which made this possible. Lastly, we consider the control that may be exerted over atomic collisions by placing atoms in superpositions of Zeeman states, and suggest that it could be useful where small changes in scattering length are required. We suggest other species for which rf and magnetic field control could together provide a useful tuning mechanism.Comment: 21 pages, 8 figures, submitted to New Journal of Physic