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Properties of the effective neutron-proton interaction of the doubly odd nuclei in the rare-earth region are studied from the energy level distance between the two rotational band heads and the mutual interaction energy between the last neutron and proton in the ground state. The result shows that the elongation of the force range has essentially the same effect as the decrease in the weight of the spin-spin term of the interaction, which is opposed to results obtained in the 1s-Od shell region. This difference is discussed from the point of view of the pairing correlation.

A method is presented for the release of “native” thin filaments from 13-day old embryonic chick muscle without tryptic digestion or desoxycholate (DOC) solubilization of Z bands. The isolated filaments were 50–60 A in diameter, of variable length, and formed “arrowhead-like” complexes with heavy meromyosin (HMM). In addition, the filaments interacted with purified myosin to form actomyosin as effectively as action extracted from an acetone powder of muscle. The Mg++-dependent ATPase activity and extent of superprecipitation of the synthetic actomyosin required a low concentration of Ca++, strongly suggesting the presence of troponin and tropomyosin on the thin filaments isolated from muscle at this stage of embryogenesis. The native thin filaments were more sensitive to trypsin than synthetic F-actin prepared from an acetone powder based on measurements of flow birefrengence, viscosity and the ability to activate myosin ATPase.

Molten aluminium is equilibrated with pure carbon over a temperature range of 800° to 1400°C under the pressure of 4×10-5mm Hg, and atmosphere. of argon Solubility of carbon in liquid aluminium under pres sure of 4×10-5mmHg is 0.10, 0.14, 0.16, and 0.32wt% at 800°, 1000°, 1100°, and 1200° respectively, and is high compared with the value obtained in the atmosphere of argon. The difference of solubility data was discussed as based on the existence of small amount of oxygen in the system. Solibility of carbon in solid aluminium is estimated to be 0.015wt% from the analytical data of graphite carbon.

Recently, a new refining method, which depends chiefly upon the partial melting of impure aluminium, has been introduced by one of the present writers. (I. Obinata; Jour. Min. Inst. Japan, 53, (1937), 542. Jap. Pat. No 124398) In this method, the vessel containing the molten aluminium is rotated about a vertical axis and cooled down until the primary crystals of. impurities, FeAl3 in particular, are separated from the eutectic mother-liquor by the action of centrifugal forces. In the present paper, aluminiums containing one or more elements, Fe, Si, Ti, Cu, Mg, Zn and Sb as impurities have been subjected for refining under various rates. From the chemical analysis of the results obtained, the follwing conclusions have been drawn; While the elimination of iron and titanium is easy, that of silicon is difficult unless it exists as a ternary compound, FeAl3 FeSi2; If aluminium contains a large amount of magnesium or zinc as impurity, the content of iron in the refined parts can be lowered below 0.8%.

The appearance of thin filaments, 60–80 A in width, in the myoblasts of early chick embryos incubated for 3 days at 39°C was observed with the electron microscope. The filaments were distributed randomly throughout the cytoplasmic matrix of the myoblasts where myofibrils had not yet been formed. These filaments were isolated from 4-day embryos by differential centrifugation; they were found in the top layers of the so-called “microsomal fraction.” The fraction showed considerable flow birefringence and an ATPase activity. Mixing of the fraction with rabbit myosin caused marked increase in the flow birefringence, and the addition of ATP to the mixture in 0.6 M KCl solution resulted in a decrease in the birefringence. The ATPase activity of myosin was enhanced about 100% by the addition of the fraction at low ionic strength. No changes in birefringence or ATPase activity took place when actin was added to the fraction. The demonstration of the reaction of the “microsomal fraction” with added myosin strongly suggests that the thin filaments in question are F-actin filaments.

Continued from the previous paper (1st report) on "Ductile type striation, " this paper discusses on the detail of brittle type striation by means of electron fractography.Brittle striations have been observed only in age-hardened aluminum alloys. They were characterized by relatively flat facets periodically marked by deep grooves. Numerous river line markings separating these facets ran normal to the striation. In the brittle crack growth, the crack front was bent in semi-circular form, but the ductile growth was relatively straight fronte d.In Al-1.5% Mg2Si alloy, the length of a side of the small facet compristing the striations and river line markings was an order of about 0.10.2μ, which was nearly the same magnitude as the length of acicular particles or interparticle spacings observed by electron microscopy.The brittle type striations showed different aspects of microfeatures under different conditions. As the results of analysis, the main features of the brittle type striations were as follows.(1) Even if the appearance of the striations was not distinct, the characteristic feature was observable relating to the distribution of precipitates.(2) The striations were bent in the neighborhord of large steps and it was suggested that the advence of crack front was arrested in the neighborhood of the steps.(3) There are many types of intermediate fracture topography with respect to the macroscopic direction of fatigue crack propagation and the orientation of individual grains (namely, microscopic direction of fatigue crack propagation).

There are two sorts of hard spot which appears in the products of die-casting, one is of metallic and the other of non-metallic nature. The former is chiefly of primary crystals of various intermetallic compounds containing iron and manganese, as shown in Table. 1 and Photo. 1, a-h.The latter or hard spot of non-metallic nature has also been detected in some products of diecasting (Photo. 4-Photo. 8), as the causes of which the reaction products between the material of crucible or fire-clays and the molten alloy as well as the slag itself contained in the crude silicon have been pointed out.Some remedies according as the causes of hard spot have been suggested.

Age-Hardening Processes can be divided, into two types: nonprecipitation and precipitation. In the former type, no precipitation, except Guinier-Preston Aggregates, may be observed until the hardness attains its maximum, while in the latter, precipitations may be detected from the early stages of the hardening pro_??_esses. Aging of the Al-Cu, Cu-Be systeme etc. in the lower temperature belong to the former and that of the Ag-Cu, Fe-Mo, systerne etc. belong to the latter. While the hardness-time curves of the Al-Cu alloy at the temperature between 0 and 70°C can be treated simply as hyperbolas with sufficient accuracy, that of precipitation type cannot be treated so. Let us define the degree of hardening as p=(H-H0)/(Hs-H0), where Hs, is the saturated hardness, H0 is the as-quenched hardness and H is the bardness at the time t, measured with Vickers or Brinell Hardness number. Then, the linear relation between 1/(1-p) and t can be realized in the case of the Al-Cu alloy at the temperature noted above and the velcsity constant of age-hardening K can be obtained from the inclivation of this line. Therefore, the activation energy of the age-hardening can be calculated from the linear relation between log K and 1/T, where T is the absolute temperature. In general, Austin-Rickett's formula (in the case of the decomposition of Austenite in steel) 1/(1-p)=Ktn+1 can be applied to both types of age-hardening, where n is nearly unity in the case of Al-Cu alloy, and is larger than unity in the case of the precipitation-type. We could deduce the Austin-Rickett's formula, in the case of age-hardening, from a few simple assumptions. We have found that the activation energy E of the age-hardening of Al-Cu alloy decreases as the concentration of Cu in the alloy decreases. The double peaks in the hardening curvei of Al-Cu alloy at high temperatures can be accounted for as follows; the first peak corresponds to the saturated hardeness of non-precipitation-hardening and the second corresponds to the maximum hardness as the result of the three-dementional growth of the aggregates.

Al-20 per cent silicon alloys containing none or only one of the following additional elements, viz. sodium, magnesium, zinc, chromium, manganese, copper, cadmium, tin, lead, antimony, bismuth, iron, nickel, and cobalt, were cooled very slowly or cast in sand molds. Then, the alloys were electrolized in hydrochloric acid solution by using lead-plate as the cathode. Silicon crystals thus obtained as the anode slime were collected and subjected to goniometry, X-ray and chemical analyses. From the above experiments, following three types of crystal habits of silicon have been detected : (1) Granular crystal, caused by addition of sodium and forming with {111} and {001} faces. (2) Prismatic crystal, caused by the addition of magnesium or zinc to the alloy and forming essentially with {111} face growing in the[011]direction. (3) Platy form crystal, which is most common and is formed in plain binary alloy or alloys containing one of the additional elements, chromium, manganese, copper, cadmium, tin, lead, antimony, bismuth, iron and cobalt, and forming with {111} faces in which one pair of the face {111} being parallel to each other is developed best. Although a small quantity of the added element was found to be contained in silicon crystals, no marked difference in the lattice constant has been found according to the crystal habit.

Fatigue crack propagation in aluminum alloys was studied in thin plate under plane bending the microscopic observation of the surface of specimen and electron fractography.There were two types of fatigue crack propagation according to the conditions of ageing. One was a continuous growth type; for instance, in Al-1.5%Mg2Si alloy after natural ageing, the fatigue crack was generated at the central hole of the specimen and was developed to grow up until final failure. The other was a discontinuous propagation type; for instance, the fatigue crack of the above alloy, fully age-hardened, predominantly propagated by the linking of many isolated cracks.The results of analysis for the growth of fatigue crack by Master curve method showed that there were two stages of the growth and only the 1st stage depended on ageing conditions. The rate of growth in the 2nd stage would be a function of the product of grass strain amplitude, eG and a square root of half crack length, √l. The transition from the 1st to the 2nd stage also depended on the ageing conditions.The examination of the fatigue fracture by electron fractography showed that characteristic feature of the fracture suface depended on the stage of crack growth and the ageing conditions. The 1st stage was the shear mode of crack growth and the surface was often characterized by parallel lamellae along the direction of the growth of the crack. The 2nd stage was the tensile mode of crack growth and the surface was characterized by the striations normal to the local direction of the crack growth. Each striation represented the position of the front oftranscrystalline crack at each load cycle. There were observed two types of striations; ductile and brittle. However, the latter was observed only in aluminum alloys fully age-hardened.

Es wurde rontgenographisch die Loslichkeitsgrenze von Aluminium in Kupfer bestimmt. Die vonStockdale angegebene Loslichkeitsgrenze wurde im wesentlichen bestatigt. Unterhalb 650° konnte keine Anderung der Loslichkeit in Abhangigkeit von der Temperatur festgestellt werden. Bei den untersuchten Aluminium-Kupfer-Mischkristallen konnte keine Abhangigkeit der Gitterkonstanten von der Korngrose oder dem Entstehungszustand der Kristalle gefunden werden. Der Notgemeinschaft der Deutschen Wissenschaft sei fur die Unterstutzung dieser Arbeit bestens gedankt.

Untersuchung der Translation; Verfestigungskurven ungleichwertiger Translationssysteme; kein einfacher Zusammenhang von Gleitfahigkeit und Belegungsdichte; kein Anzeichen eines Umwandlungspunktes bei erhohten Temperaturen.

Dieser Bericht soll einige neue metallurgische Verfahren in Vorschlag bringen, die die Zentrifugalkraft bei den erstarrenden Legierungen so bewirken, dass diese Legierungen in verschiedenen Phasen zergliedert werden. Das eine der Verfahren bezweckt, unter Benutzung von der Zentrifugalkraft bei einer erstarrenden Legierungen, soiche Phase, welche grosseres Spezifischesgewicht hat, an einen Teil des Gefasses zu verdichten. Das wird “Phasenverdichtungsverfahren durch die Zentrifugalkraft” genannt. Das andere Verfahren benutzt die Flussbarkeit der Schmelze. Man wird die halbgeschmolzene Legierungen in einem Gefass mit vielen Lochelchen umdrehen. Dann werden nur die Schmelzeteile, durch die Wirkung der Zeritrifugalkraft, ausfliessen and von der Festephase getrennt. Das wird “Trennungsverfahren der Schmelzphasen durch die Zentrifugalkraft” genannt. Als Anwendungsbeisphiele der Zentrifugalmetallurgie sind in dieser Berichte die folgenden erwahnt: 1. Raffination des Aluminium-Ruckflussgutes. 2. Raffination des Kupfer-Ruckflussgutes. 3. Entsilberung des Werkbleis. 4. Herstellung der olenthaltigen Lager.

Soaking the annealed Al-Cu alloy or duralumin in the nitre-bath heated at 540° or 500° respectively, the solution-velocities of various precipitates in the alloys have been determined rontgenographically. The effect of the rate of dissolution of the precipitates on the aging properties of the alloys has also been investigated. The results obtained may be summarised as follows: (1) The dissolution of CuAl2 at 540° in aluminium takes place at first very rapidly; for instance, it is 80% with the 3 minutes-soaking and nearly 90% with the 10 minutes-soaking. Although no marked difference in hardness of the alloys after aging has been detected, the alloys soaked for a short time in the nitre-bath showed the tendency to harden rapidly during the aging, compared with those soaked for a longer time. (2) In the case of duralumin, the solution-velocities of various precipitates, namely, CuAl2, Mg2Si, Al13 Cu7Mg8, AlMn6, etc., seemed to differ with each other; it is certain that the solution-velocity of Mg2Si is smaller than that of CuAl2. In order to dissolve the precipitates almost completely into a solid solution, the duralumin should be soaked at least for 20 minutes at 500_??_510°

Continued from the previous report on fatigue fracture topography in aluminum alloys, this paper discusses on the effects of constituent particles in ductile striation structure on the rate of fatigue crack propagation by the observation of electron fractography.As the results, even if the width of plastic zone at the crack tip was larger than the spacings between the particles arresting effects were observed under various conditions as well as accelerated effects of the constituent particles on the crack propagation, which had been pointed out by Piper3)and Pelloux4).The effects of constituent particles on fatigue crack propagation was so complicated that further systematic investigations are necessary in future in connection with the effects of particles on the formation of substructure in the plastic zone.

In order to determine the effects of non-uniformity of oxide dispersion on the mechanical properties of sintered aluminum powder alloys, two series of the alloys containing the same amounts of oxide, having different uniformity of dispersion, were prepared by powder metallurgy process. The experiments were conducted mainly for the comparison of their ductilities.Reduction of the uniformity resulted in the decrease of yield strength at room temperature, but in the marked increase of ductility for the alloys containing less than 7% (vol.) of oxide. The results of tensile tests were compared for the two series of the alloys up to 500°C. It was shown that the alloys of nonuniform dispersion had little dependency of ductility on temperature, but exhibited a large amount of work by tensile deformation in plastic region. Hardness of non-uniform dispersion alloys revealed higher thermal stability in the heat-treatment after cold rolling, as compared with that of uniform dispersion alloys having considerably high thermal stability as extruded material. The results of density measurement and fractographical observation of tensile fracture suggested that brittleness at high temperatures was closely related to the void formation due to gases released by the decomposition of hydrated aluminum oxide in the aluminum powder.It is concluded that appreciable improvements in mechanical properties of these alloys can be expected by proper control of uniformity of oxide dispersion and also by preliminary degassing treatments of powder before compacting process.

Properties of the effective neutron-proton interaction in deformed light nuclei, such as 18, 20 F, 22, 24 Na, 26, 28 Al), 30, 32 P and 34 Cl, are studied using experimental data on the energy difference between the two rotational band heads and the mutual interaction energy between the neutron and proton in each nucleus by using a symmetric core rotational model. The results show that the systematics of the experimental data can be explained by our simple model. The value of the effective-force range parameter obtained is fairly short compared with the range which is usually employed in the spherical shell-model calculation. In connection with these results, the effects of the force range and force mixture on the nuclear deformation are discussed.