Sintering of Acicular Fe2O3 Powder

The sintering of acicular Fe₂O₃ powder has been studied in comparison with an ordinary equiaxed powder. The acicular powder gave a dense material more than 99 % theoretical even from the relatively low green density. Oriented granular structures were observed in the 1200°C compacts. The observed densification behavior has been attributed to the pore configuration in the green compact.     

Small-angle X-ray scattering from heparin in solution

Summary X-ray small-angle scattering fron heparin in solution was measured, and compared with theoretical curves based on various nolecular models. Good agreement was obtained for the model consisting of -D-glcosamine in the ⁴C₁ conformation and -L-iduronate in the ¹C₄ conformation. It was suggested that the helical conformation is maintained even in solution, at least in part. The helix pitch was estimated to be 0.75–0.85 nm.     

Fiber-strengthening of a Cu−Fe−Cr duplex alloy by cold drawing

Copper wire containing strong chromium ferrite needles has been produced by aligning the chromium ferrite phase of a two-phase Cu?Fe?Cr alloy into needles by cold drawing and subsequently annealing the wire at 480°C. At this temperature the chromium ferrite needles exhibit marked age-hardening. The volume fraction of the chromium ferrite needles in the alloy investigated was nearly 25 pct. Strength up to 50 kg per sq mm with nearly 8 pct elongation has been achieved in 3 mm-wire annealed at 480°C. The annealed wire can be drawn again to give a further increase in strength up to 73 kg per sq mm.     

Polymerization of methyl methacrylate in the presence of graphite

The polymerization of methyl methacrylate was carried out in the presence of graphite powder in water medium containing sulfur dioxide. The polymerization was initiated by a redox reaction between ash in graphite and HSO₃^?. Graphite powder encapusulated with polymethyl methacrylate was obtained in high yield. The mechanism of the polymerization and the capusulation are discussed.     

Rotational and alternating hysteresis losses in 4% silicon-iron single crystal with the {110} surface

The rotational and the alternating hysteresis losses have been measured on small discs of 4% silicon-iron with the {110} surface, and the results have been explained on the basis of the changes in domain-structure observed under various conditions. It has been clarified that the magnetization under the rotating field or the alternating field in the <110> direction proceeds by forming finely divided 90° domain-structure and that the greater part of the hysteresis loss under such conditions can be attributed to the energy dissipation due to the annihilation of domain walls. The thickness dependence of the hysteresis losses has been explained from the changes in domain-wall spacing.     

Design of surface-acoustic-wave filters by taking account of electrical terminations and matching circuits

This letter describes a method of determining overlap width for interdigital electrodes of s.a.w. filters by taking account of electrical terminations and matching circuits. A filter with 22.5% bandwidth is designed by use of damped least squares. Since the amplitude response in the passband can be considerably improved compared with that designed by a Fourier analysis, this method may be useful when the required passband shape is strictly specified.     

Combustion improvement in a hydrogen fueled engine

Experimental testing of hydrogen-fueled engines has verified that hydrogen can be used safely and easily and is a promising fuel for automobiles. However, there are problems with abnormal combustion and NO_x formation. This paper discusses the phenomena of abnormal combustion and presents a correlation between the abnormal combustion and No_x formation. Elimination of these problems was accomplished after several engine modifications and by an experimentally-developed “combined combustion process.” The characteristics of a hydrogen-oxygen engine with a hydrogen rich fuel mixture were also studied. This engine was found to have an unexpectedly narrower range of operation than a hydrogen-air engine.     

Mechanochemistry and permeability of polyelectrolyte complex membranes composed of poly(vinyl alcohol) derivatives

Two polyanions and two polycations were prepared by the esterification of poly(vinyl alcohol). Properties of their neutral polyelectrolyte complex membranes were compared with those of polyelectrolyte membranes. The charged state on the membranes was related closely to the mechanochemical reaction, the salt rejection, and the solution permeability. Both the salt rejection and the water flux of neutral polyelectrolyte complex memberanes were lower than those of the corresponding acidic or basic complex membranes.     

Electrophysiologic effects of anterior septal arterial occlusion

The effect of reduction in anterior septal arterial flow on the conduction system was studied in seven anesthetized dogs. After 2 hours of occlusion P-Q, A-H, and H-V intervals as well as atrioventricular nodal effective and functional refractory periods were significantly prolonged, sinoatrial conduction time was prolonged and the heart rate was decreased. The duration of the His bundle electrogram was significantly prolonged and the configuration altered. However, QRS duration did not prolong significantly. Fifteen minutes after reperfusion, A-H interval, duration of the His bundle electrogram, effective refractory period and functional refractory period returned toward control values. However, the H-V and QRS intervals as well as sinoatrial conduction time were unchanged after reperfusion. Thus, reduction of anterior septal arterial flow influences not only the distal but also the proximal portion of the conduction system; the most vulnerable part is probably the His bundle. The distal portion of the conduction system is directly influenced by ischemia itself, whereas the proximal portion is influenced through other mechanisms induced by reduction of anterior septal arterial flow.