A novel method for the synthesis of 1-aryltetrahydroisoquinolines

Carbenium ions generated from substituted benzhydryls using acid catalysis undergo smooth intramolecular trapping by pendant sulfonamide groups to provide excellent yields of 1-aryltetrahydroisoquinolines.     

Shock synthesis of lanthanum-III-pernitride

Lanthanum-III-pernitride is unique amongst pernitrides because of the seemingly misfit charge balance and stoichiometry. La⁺³N₂ has been predicted to be stabilized by resonance between two mesomeric states of bonding in the pernitride group, which include a remarkable N?N single bond limiting state. However, successful synthesis of this compound remained extant. Here, we report synthesis of LaN₂ through shock-driven decomposition of lanthanum nitrate. The result is noteworthy as a first quantitative measure of the stability of N?N single bonds in solids formed at GPa-level pressure and with respect to a possible cross-over of redox potentials in the nitrogen- and oxygen-systems at high pressure and temperature.     

50 years at the forefront of Physics

Mathemtical Techniques and Physical Applications. By J. Killingbeck and G. H. A. Cole. (Amdemic Press, 1971.) [Pp. xiv + 715.] £7£00. Scope: Textbook; reference. Level: Postgraduate; undergraduate.

Group Theory in Solid-state Physics. By H. W Streitwolf (Macdonald, 1971.) [Pp. 248.] £5·00. Scope: Textbook. Level: Postgraduate.

Statistical Physics. By Ya. P. Terletskii. (North-Holland, 1971.) [Pp xv+279.] $6·30. Scope: Textbook. Level: Postgraduate; undergraduate.

Ubsersichtsbeiträge zur Gasdynamik. Edited by E. Leiter and J. Zierep. (Springer-Verlag, 1971.) [Pp. 386.1 $40·70. Scope: Treatise. Level: Specialist/postgraduate.

Classical Theory of Particles and Melds. Vol. I and Vol. II. By K. H. Ruei. (University Press, Taiwan, Republic of China, 1971.) [Pp.: Vol. I, xxiii + 359; Vol. II, xxvi + 424.] Scope: Textbook. Level: Postgraduate; undergraduate.

Topics in Mathematical Physics. Vol. II: Spectral Theory and Wave Processes. By M. Sh. Birman. (Consultants Bureau, 1971.) [Pp. v + 121.] $14·00. Scope: Treatise. Level: For specialists only.

An Introduction to the Theory of Electromagnetic Waves. By A. C. Hewson. (Longman, 1971.) [Pp. viii+ 115.] £ 1·60. Scope: Textbook. Level: Undergraduate.

Modern Physics and Quantum Mechanics. By Elmer E. Anderson. (W. B. Saunders Co. Ltd., 1971.) [Pp. xi+430.] £6·20. Scope: Textbook. Level: Undergraduate.

Polarized Light and Optical Measurement. By Clarke and Grainqer. (Pergamon Press, 1971.) [Pp. viii+ 187.] £3·50 ($9·50.). Scope: Treatise. Level: Specialist/postgraduate.

Phenomena in Ionized Gases 1971. Edited by R. N. Franklin. (Donald Parsons, 1971.) [Pp. xl+450.] £12·00.

Technology Today. Edited by Edward de Bono. (Routledge &; Kegan Paul Press, 1971.) [Pp. xii+ 144.] Cloth edition £1·75; Paperback 50p. Scope: Survey. Level: General reader.

Diffusion Data. No. 1. Edited by DR. F. H. Wohlbier. (Trans Tech Publications, 1971.) [Pp. 289.] Scope: Library (reference). Level: Specialist/postgraduate.     

Role of pH and charge on silk protein assembly in insects and spiders

Silk fibers possess impressive mechanical properties, dependant, in part, on the crystalline β-sheets silk II conformation. The transition to silk II from soluble silk I-like conformation in silk glands, is thought to originate in the spinning ducts immediately before the silk is drawn down into a fiber. However the assembly process of these silk molecules into fibers, whether in silkworms or spiders, is not well understood. Extensional flow, protein concentration, pH and metal ion concentrations are thought to be most important in in vivo silk processing and in affecting structural conformations. We look at how parameters such as pH, [Ca²⁺], [K⁺], and [Cu²⁺], and water content, interact with the domain structure of silk proteins towards the successful storage and processing of these concentrated hydrophobic silk proteins. Our recent domain mapping studies of all known silk proteins, and 2D Raman spectroscopy, NMR, and DLS studies performed on sections of silkworm gland, suggest that low pH and gradual water removal promote intermolecular over intramolecular hydrogen bonding. This discussion helps to provide the necessary ground rules towards the design of silk protein analogues with specific hydrophobicity and charge profiles to optimize expression, solubility and assembly with implications in structural biology and material science. PACS 87.14.Ee; 87.15.Cc; 87.15.Kg     

Maximization of supercontinua in photonic crystal fibers by using double pulses and polarization effects

We show with sub-20 fs pulses both experimentally and theoretically two techniques to control the width and polarization of spectral supercontinua generated in photonic crystal fibers. The first exploits double pulses which interact inside the fiber nonelastically due to stimulated Raman scattering and thus make the supercontinuum wider, whereas the peak intensity can be kept at a reasonably moderate level to prevent fiber damage. The second approach includes polarization manipulations which allow a desirable polarization state to be obtained in a definite spectral range and the spectral shape and width to be varied. PACS 42.65.Tg; 42.81.Dp     

Thermodynamic Stability of Transition‐Metal‐Substituted LiMn2−xMxO4 (M=Cr,Fe, Co,and Ni) Spinels

The formation enthalpies from binary oxides of LiMn₂O₄, LiMn_2?xCr_xO₄ (x=0.25, 0.5, 0.75 and 1), LiMn_2?xFe_xO₄ (x=0.25 and 0.5), LiMn_2?xCo_xO₄ (x=0.25, 0.5, and 0.75) and LiMn_1.75Ni_0.25O₄ at 25 °C were measured by high temperature oxide melt solution calorimetry and were found to be strongly exothermic. Increasing the Cr, Co, and Ni content leads to more thermodynamically stable spinels, but increasing the Fe content does not significantly affect the stability. The formation enthalpies from oxides of the fully substituted spinels, LiMnMO₄ (M=Cr, Fe and Co), become more exothermic (implying increasing stability) with decreasing ionic radius of the metal and lattice parameters of the spinel. The trend in enthalpy versus metal content is roughly linear, suggesting a close‐to‐zero heat of mixing in LiMn₂O₄—LiMnMO₄ solid solutions. These data confirm that transition‐metal doping is beneficial for stabilizing these potential cathode materials for lithium‐ion batteries.     

Nearly viscometric flows in the new rheometers

Summary The linear time-dependent behaviour of elasticoviscous liquids may be determined by conventional rheometers, or by any one of a number of new rheometers which have recently appeared in which the test fluid is contained between two surfaces which rotate with the same angular velocity about axes which are not coincident. (The Orthogonal, Balance and Eccentric-Cylinder rheometers are perhaps the most well known examples of such instruments at the present time.) In this communication, we consider the more general situation in the new rheometers in which the angular velocities of the two surfaces are different.The first part of the paper is concerned with experimental results from the Eccentric-Cylinder Rheometer, with particular reference to the case in which the speeds of the two members are almost the same. The results throw light on the important problem of lag brought about by bearing friction.The main body of work concerns a study of the potential use of the combined steady and oscillatory shear type of flow generated when the instrument members are driven at different speeds. The Balance rheometer is concluded to be of very little use in this connection, and most of the attention is confined to the nearly-viscometric flows generated in the Orthogonal and Eccentric-Cylinder rheometers. It is concluded that the analysis for the Orthogonal Rheometer is too complicated to have any predictive value, but that generalized Eccentric-Cylinder flow may be useful in the context of model assessment.With 4 figures     

Use of multiscale particle simulations in the design of nuclear plant decommissioning

The application of a digital modelling method that can faithfully take account of three-dimensional shape and inherent physical and chemical properties of each particulate component provides an essential tool in decommissioning design. This is useful in handling of high, medium and low level radioactive waste. The processes involve making decisions on where to cut existing plant components and then how to pack these components into boxes, which are then cemented and kept for long term storage as the level of radioactive declines with time. We illustrate the utility of the method and its ability to take data at plant scale (m-scale) and then deduce behaviours at sub millimetre scale in the packed containers. A variety of modelling approaches are used as a part of this approach including cutting algorithms, geometric and dynamic (distinct element) force models, and lattice Boltzmann methods. These methods are applicable to other complex particulate systems including simulation of waste, building recycling, heap leaching and related minerals processes. The paper introduces the basic concepts of this multi-scale and multi-model approach.     

Preparation of 1-(Benzyloxycarbonyl) Hexahydro-3-Pyridazine Carboxylic Acid,A Protected Piperazic Acid

A preparation of l-(benzyloxycarbonyl)hexahydro 3-pyridazinecarboxylic acid in five steps (73% overall yield) from 4-phenylurazole is described.