Connection between hardness and stresses in the plastic region

In studying plastic deformation by measurement of hardness [1] it is necessary to use a hardness-stress calibrating graph plotted from the results of tests under the simplest stress conditions. For the use of these graphs in plastic deformation in general to be well-founded, it is essential to have experimental data confirming that the hardnessstress curve is common to various states of stress. However, [1–3] give this data from tensile, compressional and torsional tests only. Clarification of this problem is particularly important, because all the stress and deformation components for a number of cases of practical importance can be determined by reference to the stress intensities at various points in a body [4].The present work gives the results of experimental work on the connection between stresses and hardness under conditions of two- and three-dimensional stress.     

Sulla derivabilità di una funzione rispetto ad un'altra

In this paper we establish some characterizations of functions which are derivable or approximately derivable almost everywhere with respect to another one supposed increasing.     

High-spin states of 26Mg populated in the 12C(18O, α) reaction

The structure of ²⁶Mg has been investigated by means of the ¹²C(¹⁸O, α) reaction. Several previously unknown states were populated between excitation energies of 0 to 16 MeV. Excitation functions were measured for 126 states for bombarding energies between 43.2 and 45.9 MeV in 300 keV steps at a lab angle of 7°. The experimental energy averaged differential cross sections were compared with statistical model calculations and good agreement was obtained for the states whose spins and parities were previously established. The statistical model calculations were used to suggest the spins and parities for the rest of the states. In particular, candidates for 6⁺ and 8⁺ states were interpreted as members of three rotational bands in ²⁶Mg: the ground-state band, the K = 2⁺ band based on the 2.938 MeV 2⁺ state, and a K = 0⁺ band based on the 3.588 MeV 0⁺ state. Back bending of the yrast band is observed and it is suggested that it may be due to band crossing of the ground-state and first excited K = 0⁺ bands.     

Search for the radiative η′(958)+γ decay of the J/Ψ (3100) resonance produced in e+e− annihilation

The decay J/Ψ (3100)→ η(958) + γ has been searched for at tthe Adone e⁺e^+- storage ring. No candidate event has been found. This allows to set an upper limit of 1.0 keV (90% C.L.) for this decay partial width.     

Correlations of secondaries in events with a forward negative hadron at the ISR

Data obtained from p-p collisions at centre-of-mass energies between 31 and 63 GeV are presented on correlations between momentum analysed forward π^?, K^? and $\text{p}$ and charged particles observed in an omnidirectional hodoscope. The data show that significant correlations are present over the whole rapidity range for all three types of negative particles. The dependence on various kinematic variables suggests a cluster mechanism for the production of particles. In this picture, pions would be produced in clusters emitted in the fragmentation region while K^? and $\text{p}$ emanate from non-leading clusters.     

A new scaffold for the stereoselective synthesis of alpha-O-linked glycopeptide mimetics

alpha-O-Linked glycohomoglutamates are obtained as diastereomerically pure compounds by chemo-, regio-, and stereoselective cycloadditions between glycals and aspartic acid derivatives. The latter constitute orthogonally functionalized scaffolds for glycopeptide mimetics.     

Trovacene Chemistry. 10 [1] The [1]- and [2]Silatrovacenophanes (η7-$\overline{C 7H6)V(η5-C5H4S}$iR2) and (η7-$\overline{C 7H6)V(η5-C5H4SiR2S}$iR2 (R = Me,Ph): Synthesis,Structure, and Ring Opening

Heteroannular dilithiation of trovacene, (η⁷-C₇H₇)V(η⁵-C₅H₅) ( 1^˙ ), and subsequent reaction with the respective dichlorosilane yielded the [1]silatrovacenophanes (η⁷-$\overline{C ₇H₆)V(η⁵-C₅H₄S}$ iR₂) ( 2^˙ , R = Ph; 3^˙ , R = Me) and the [2]silatrovacenophane (η⁷-$\overline{C ₇H₆)V(η⁵-C₅H₄SiMe₂S}$ iMe₂) ( 4^˙ ). Structural studies by X-ray diffraction revealed sandwich tilt angles of 17.3° ( 2^˙ ) and 3.8° ( 4^˙ ), respectively, and considerable strain in the ring-link-ring region. EPR spectroscopy responds to these distortions in that the g-tensor is tetragonal (g_x = g_y ≠ g_z) for 4^˙ but rhombic (g_x ≠ g_y ≠ g_z) for 2^˙ and 3^˙ . With increasing tilt, <g> increases slightly towards g_fs = 2.0023 and a(⁵¹V) decreases, the latter response to tilting being more pronounced. These trends are plausible in view of distortion-induced mixing of the V(3d) SOMO with ligand π orbitals. Whereas cyclic voltammetry of undistorted 4^˙ displays reversible oxidation and reduction, the strained sandwich 2^˙ shows irreversible behavior, probably caused by cleavage of the interannular bridge. [1]Silatrovacenophanes are thermally more robust than [1]silaferrocenophanes in that 2^˙ , exposed to 280 °C, fails to show indications of ring-opening polymerization (ROP).