Young Modules Research Articles

NMR Investigation on Molecular Dynamics in Solid C_(60)

1 Introduction At room temperature, C_(60) takes a crystal structure in which C_(60) molecules arepositioned with their center of mass on an f_∞ (face-centered-cubic) lattice. IndividualC_(60) molecule's reorientational rapid motion shows up as orientational disorder. At250 K—260 K, the f_∞ lattice system undergoes a first-order transition to a simple cubic(sc) structure with P_a~3 symmetry. Even in the ordered phase, the short-rangedisorder persists to the lower temperature. Recently Shi X. D. et al. reported the studies of the elasticity of C_(60)single crystals. For sublimed f_∞ crystals, Young's modules had an 8% jump at the

Mechanical Properties of Glass and Polycrystalline Ceramic with Cordierite Composition

The Vickers hardness (Hv), Young's modules (E), fracture toughness (KIC) and bending strength (σf) of a glass and an α-type polycrystalline cordierite with the cordierite composition (2MgO⋅2Al2O3⋅5SiO2) were measured using Vickers indentation, resonance method, various indentation techniques and 3-point bending test. The polycrystalline cordierite was fabricated by densification and subsequent crystallization of compacted cordierite glass powder. The Hv, E and KIC of a polycrystalline cordierite were 7.5GPa, 127.5GPa and 2MPa⋅m1/2, while those of cordierite glass were 5.9GPa, 98.7GPa and 1.0MPa⋅m1/2, respectively. On the other hand, the σf (113MPa) of a polycrystalline cordierite was smaller than that (149MPa) of a cordierite glass.

Microstructure and Mechanical Properties of Mullite Ceramics

Microstructural effects on the mechanical and thermomechancical properties of mullite ceramics have been investigated. The mullite ceramics were fabricated by reaction-sintering of mixture of kaolin and Al2O3(M-1) and by pressureless-sintering of a powder prepered from Al2O3 and SiO2 sols (M-2) and Al2O3 sol-ethylsilicate (M-3) system from the sol-gel method. Transmission electron microscopic observation revealed that samples M-1 and M-2 contained foreign phases, but that they were much less in M-2. These showed different temperature dependence in mechanical properties such as hardness, Young's modules, fracture toughness and strength. These differences were explained by the amount of grain boundary impurity phases. Thermal shock fracture behavior was also discussed.

Structural modification of arsenic chalcogenide glasses under γ-radiation

The radiation-induced changes of the molecular structure and properties of chalcogenide glassy semiconductors are analysed. The effect of γ-radiation on the mechanical properties (Young's module, internal friction) of glassy arsenic chalcogenides is investigated at various temperatures and radiation doses. At low temperatures the changes of the molecular structure and the corresponding changes of mechanical properties of the chalcogenide glasses under the influence of γ-radiation grow with the decrease of the structural network rigidity. On the other hand at higher temperatures the opposite dependence of the properties is found. [Russian Text Ignored].

国内産バレイショでんぷんの理化学的諸性質とそれらの相互作用について

Most of potato starches are produced in Hokkaido prefecture in Japan. Some physicochemical properties of potato starches produced in 17 representative potato starch factories in Hokkaido were investigated. The values in each properties and the Gorrelations among rheological properties of starch pastes and gels, average size of starch granule and mineral contents were calculated. It was found that (1) maximum viscosity in amylograms was closely connected with dynamic viscosity of pastes, Young's modules of gels and potassium content, (2) average size of starch granule had close relationships to dynamic modulus of pastes, Young's modulus and strain ratio of gels, and (3) phosphorus content had relatively high relation to breaking strength of gels.

A Study on the Characteristics of Hot-Rolled “2V Permendur” Sheet

In order to clarify the order-disorder transformation mechanism of the hot-rolled 2V Permendur sheet, the characteristics of various heat-treated specimens were investigated with regard to their roll directions.The results obtained in this study can be summarized as follows:(1) The magnetostriction is dependent upon the roll directon, and shows its maximum value at the angle 45° except in the furnace-cooled state from 1050°C.(2) The magnetostriction vs. heat-treatment curves at H=1600 Oe are almost similar in any direction. The magnetostriction becomes largest after furnace cooling 1050°C, and decreases to the minimum after water quenching at 680°C, but increases at 750°C, then decreases again at 850°C and shows the tendency of slight increase at higher temperatures. These tendencies do not change at H=50 Oe, although the magnetostriction shows again the minimum at 950°C.(3) The intensity curves of magnetization vs. roll direction at H=50 Oe after various heat-treatments are found to be analogous to those for magnetostriction.(4) Young's modulus in γ phase is dependent upon the roll direction.(5) The effects of roll direction on Young's modulus in an ordered state are quite different from those in a disordered state, and Young's modulus in the former is generally larger than that in the latter.(6) In (α+γ) phase, Young's modulus is largest after a water quenching at 950°C.(7) Young's modules vs. heat-treatment curves are much the same in all directions.(8) The cooling effect due to quenching is pronounced rather in cold water than in liquid nitrogen.

Studies on the Stiffness of Culms in Barley Plants (Hordeum sativum, JESSEN) : 15. Physiological studies on the stiffness of culms by <SUP>14</SUP>C-tracer method(2)

A brittle culm variety, Sekitorisai-No. 1 and three stiff culm varieties, Haganemugi, Mitake, and Dorirumugi were used. The present studies were carried out in attempt to get background information on the mechanical properties of brittle and stiff culms. Haganemugi and Mitake, as compared with other varieties, were found to be superior in respect of the moment of inertia of cross sectional area of the culm. On the other hand, Dorirumugi showed a higher value in YOUNG's modules than other varieties. In Haganemugi and Mitake, the dry weight was higher and the amounts of assimilated-14C, cellulose, and silica accumulated in the culms were more than those in other varieties. Therefore, Haganemugi and Mitake are considered to be superior to other varieties in respect of culm growth, as they have large culm diameters and thick culm walls. Dorirumugi was found to be superior to other varieties, so far the number of vascular bundles per unit area of cross section of the culm is concerned. The greater mechanical culm strength in Dorirumugi variety was therefore supposed to be the contribution of the higher number of vascular bundles in unit area corresponding to those in other varieties. Based upon the above facts, the culm stiffness, which is significantly ascribed to the increase in YOUNG's modules or moment of inertia of cross sectional area of the culm, is considered as one of the most important factors for resistance against lodging. Therefore, it might be concluded that the shorter the culm becomes, to a certain extent, the more the buckling load is increased.