Evaluation of forces in magnetic materials by means of energy and co-energy methods

The evaluation of the total force of magnetic origin acting upon a body in a stationary magnetic field is often carried out using the so-called magnetic energy (or co-energy) method, which is based on the derivation of the magnetic energy (or co-energy) with respect to a virtual rigid displacement of the considered body. The application of this method is usually justified by resorting to the energy conservation principle, written in terms both of electrical and of mechanical quantities. In this paper we shall re-examine the whole matter in the context of classical thermodynamics, in order to obtain a more comprehensive and general proof of the validity of the energy (or co-energy) approach and to point out its limitations. Two typical configurations will be discussed; in the first one, the field sources are represented by conducting bodies carrying free currents, whereas in the second one a permanent magnet creates the driving field. All magnetic materials are assumed to be non-hysteretic and permanent magnets are represented by means of the well-known linear model in the second quadrant of the (B,H) plane. Received 25 July 2001 and Received in final form 5 November 2001     

Transient fieldg-factor measurement of the first 3− state in144Sm

The g-factor of the octupole vibrational state 3⁻ at 1810 keV in¹⁴⁴Sm has been measured to be 0.76(9) by means of the transient field technique. The state has been Coulomb excited by 217 MeV⁵⁸Ni beam. The obtained value agrees with the predictions of RPA calculations and confirms the dominance of the proton particle-hole configuration π(1h_11/2−2d_5/2 ⁻¹)     

An efficient conversion of berberine into a rhoeadine via an indenobenzazepine

Treatment of ketoaziridine $\text{4}$ with aqueous formaldehyde gives the unusual bridged indenobenzazepine derivative $\text{6}$ whose reduction uith sodium cyanoborohydride produces trans ketol $\text{8}$. In the presence of hydrochloric acid, $\text{8}$ undergoes irreversible conversion to the more stable cis ketol $\text{10}$. Periodate oxidation of $\text{8}$ supplies γ-laotone $\text{11}$. NaBH₄ reduction of $\text{11}$ followed by acid treatment affords δ-lactone $\text{12}$ which upon reduction and O-methylation furnishes cis rhoeadine analog $\text{14}$.     

Strained cyclobutane compounds: 1H NMR analysis of a new 1-substituted benzobicyclo[3.1.1]heptene system

The ¹H NMR spectra of a number of new derivatives of benzobicyclo[3.1.1]heptene were examined and interpreted by using a single set of coupling constants. All the compounds belonging to this system are in a γ-shaped configuration. Surprisingly, two different proton-proton spin-spin coupling constants (⁴J=5.5 to 6 Hz and 8.5 Hz) were obtained for the cyclobutane ring.     

Differential cross sections for K+n elastic scattering between 0.64 and 1.51 GeV/c

We present experimental results on the K⁺n → K⁺n differential cross sections measured in deuterium at 13 momenta between 0.64 and 1.51 GeV/c.     

Measurement of onset potentials for proton transfer reactions with a triple quadrupole instrument

Problems with the treatment of data from the study of both exothermic and endothermic ion-molecule reactions are discussed. Recommendations are (i) to extrapolate data from an obviously linear region in the plot of ratios of secondary to primary ion intensity which appears ～1–3 V above the value of the onset potential; (ii) to use ionization methods that give low internal energies to primary ions; (iii) to set for moderately high resolution; (iv) to check the stability of the primary ion current frequently; (v) to pay special attention heed to source and collision region pressure stability; and (vi) to keep collision region pressures below 0.6 mPa.