Showing papers by "Tokyo Institute of Technology published in 1969"

Mechanism of the Action of Taste-modifying Protein

Abstract: THE “taste-modifying protein” that has been isolated from miracle fruit (Synsepalum dulcificum)1 is a basic glycoprotein with a probable molecular weight of 44,000. Applied to the tongue it modifies taste so that sour substances taste sweet. Brouwer et al.2 have isolated a similar protein from miracle fruit. We describe here a psychological study of the protein designed to clarify its mechanism of action.

Early Hydration of Tricalcium Silicate: A Solid Reaction with Induction and Acceleration Periods

Abstract: The hydration of tricalcium silicate was studied using a sample with a limited particle size distribution. The hydration reaction was analyzed as an example of general solid reactions having induction and acceleration periods. The first product, which may have a structure similar to the reactant, forms on the surfaces of reactant grains. The nuclei of the stable product are produced in the first product layer and act as reaction centers; the main reaction to form a stable product occurs rapidly in the acceleration period. In the hydration of calcium silicates, hydrates produced in this stage are poorly crystalline and metastable and change gradually into a more stable form.

Electrical and Optical Properties of Sputtered CdO Films

Abstract: CdO films were prepared by a D–C reactive sputtering method with various sputtering voltages. The characters of the prepared films are compared with the reflection electron diffraction and X-ray diffraction patterns. Especially, the effects of the sputtering voltage and partial pressure of oxygen were investigated concerning the electron densities and the Hall mobilities. The observations on lattice parameters lead to the conclusion that CdO films with high carrier concentrations contain some amount of interstitial excess Cd atoms. The absorption edge variation of annealed films prepared by high voltage sputtering agrees with the theoretical curve which is accounted from the Fermi level shift caused by the change in carrier concentrations.

Fixed point theorem for amenable semigroup of nonexpansive mappings

Abstract: Let K be a subset of a Banach space B. A mapping 5 of K into B is said to be nonexpansive if for each pair of elements x and y of K, we have \\\\sx—sy\\\\^\\\\x—y\\\\. Kakutani [5] and Markov [7] proved the following theorem: Let K be a compact convex subset of a locally convex linear topological space B and S be a commuting family of linear continuous mappings of K into itself. Then S has a common fixed point in K. Day [2] showed that this is true even if S is an amenable semigroup. On the other hand, de Marr [3] proved a fixed point theorem for a family of nonlinear mappings: Let K be a nonempty compact convex subset of a Banach space B. If S is a nonempty commutative family of nonexpansive mappings of K into itself, then the family S has a common fixed point in K. The question naturally arises as to whether this is true if one considers an amenable semigroup of nonexpansive mappings. In this paper, we shall show that the answer is affirmative.

Optimal control of systems with transportation lags

Abstract: Simultaneous use of first-order partial differential equations and ordinary differential equations, instead of differential-difference equations, is presented to define systems involving transportation lag processes. Variational analysis is carried out for the system to obtain an optimal control law which minimizes a specified objective function, and the strong maximum condition which has to be satisfied by the optimal control is derived and discussed. The theory developed is rather general and may be applied to a class of systems wider than those defined by differential-difference equations.

Electrical Properties and Mössbauer Effect in the System Sr 2 (FeMo x W 1-x )O 6

Abstract: A series of solid solutions between Sr 2 (FeMo)O 6 and Sr 2 (FeW)O 6 were synthesized and their electrical properties were studied by the measurements of both the temperature dependence of the electrical conductivity and the Seebeck coefficient. The valence states of iron ions were studied by the Mossbauer effect measurements. The compounds in the range (0.5≤ x ≤1) have high conductivity (ρ≃10 -3 ohm·cm) with the metallic type. The valence distribution between the B sublattice ions is considered to be Sr 2 (Fe 3+ Mo x 5+ W 1- x 5+ )O 6 . The compounds in the range (0.3≤ x ≤0.4) is considered to be a semiconductor with a very small energy gap or a degenerate semiconductor. And the compound in the range (0≤ x ≤0.2) may be called semiconducting. A mixed valence compound Sr 2 (Fe 1- x 2+ Fe x 3+ Mo x 5+ W 1- x 6+ )O 6 will be formed in the range (0≤ x ≤0.1). The rapid change in valence in the range (0.1≤ x ≤0.4) is evidenced by a rapid replacement of the Fe 3+ ions for the Fe 2+ ions.

Magnetic Properties of Cr 7 Te 8

Abstract: Cr 7 Te 8 exhibits two types of crystal structure according to the difference of thermal treatment; one is the ordered and the other is the disordered arrangements of the vacancies among the successive Cr layers The saturation moments and the magnetic susceptibilities of both structures are measured in the temperature range from 77°K to 1000°K It is observed that the magnetic properties depend largely on the arrangements of the vacancies In addition, at 42°K two nuclear magnetic resonance absorption lines are observed at 451 and 582 MHz in the ordered samples whereas a very broad absorption line is observed in the disordered samples These absorption lines may be considered as Cr 53 -signals from the measurements in the external magnetic field It seems that these magnetic and NMR date are interpreted by the ionic model, though the interpretation includes some degree of incompleteness

An improved circuit theory of a multielement antenna

Abstract: An integral equation for a multielement antenna having finite gaps at the driving points is derived. An approximation of this equation is calculated on the assumption that the gap capacities are negligible as is the case with ordinary antennas, and it is used to explain the stationary property of the input impedance. If the electric current distribution is expressed by the sum of a number of trial functions, the equation for determining the coefficients of the functions is found from this condition for the stationary properties. This equation is an improvement of the circuit equation for antennas written in terms of self- and mutual impedances defined by the EMF method. The mutual impedance is affected by all antenna elements. The trial functions for the electric current distribution must be smooth near the driving points and must be approximately constant within the gap. Numerical calculations on a circular array consisting of five full-wavelength cylindrical antenna elements are shown to verify the usefulness of the improved theory.

Correlation Among Methods of Preparation of Solid Catalysts, Their Structures, and Catalytic Activities*

Abstract: Publisher Summary This chapter describes the traditional methods of preparation of supported nickel catalyst, such as superhomogeneous coprecipitation (SHCP) method, cation exchange method, palladium on aluminosilicate by complex-ion exchange, palladium on active charcoal, and nickel-phosphorus alloy. The catalytic activity of a solid catalyst, including its selectivity and life, is one of the attributes inherent to this solid substance itself and, therefore, depends on its physical and chemical structures, which are, in turn, governed by the method of preparation of this solid substance. The catalytic reaction on the solid catalyst is a kind of reaction that occurs between the reactant and the catalyst surface and, therefore, the physical and chemical structures of the surface must be among the main controlling factors of the surface reaction. The surface of the solid catalyst is heterogeneous in the geometrical composition of atoms and also in the distribution of surface energy.

Continuous operation of emulsion polymerization of styrene

Abstract: The change in number of polymer particles formed in the continuous emulsion polymerization of styrene under operational conditions is theoretically analyzed on the basis of the authors'' kinetic data, previously obtained in a batch reactor. The phenomenon of the limit cycle observed in this continuous system is explained. It is noted that the application of "the seeder" to formation of polymer particles will be recommended in practical operations.

X-Ray Topographic Observation of Copper Whisker Crystals

Abstract: Copper whisker crystals, carefully grown from cuprous iodide by vapour reduction, were studied by means of x-ray topography and optical microscopy. About 50 whisker crystals with growth orientations [001], [110] and [111] were examined in a thickness range from 10 to 80 µ. None of them contained an axial dislocation. The same was true for kinked and spiral whisker crystals. The whisker crystals are in a high degree of perfection even at the thickness of 80 µ, although some of them contained lattice defects introduced accidentally during the growth. Results obtained indicate that copper whisker crystals do not grow by the growth mechanism, in which an axial screw dislocation plays an important role. There is a contrast change at the tip of the whisker crystal. Impurities at the tip may take part in the growth.

Drawing of single‐crystal mats of linear polyethylene

Abstract: Drawing of single-crystal mats of linear polyethylene has been investigated. Drawing is possible at temperatures higher than about 90°C. The drawing is accompanied by distinct necking, with a large decrease in the thickness of the mat and a very high maximum draw ratio, sometimes over 30. The maximum draw ratio is approximately proportional to the thickness of the lamellae. This behavior strongly suggests the unfolding of chains during drawing. A change of orientation of crystal axes occurs before necking without change of lamellar orientation. The a axis orients in the drawing direction; the b axis orients perpendicular to the direction of drawing; and the chain axis tilts away from the thickness direction of the mat. The structure of films drawn from mats is characterized by a distinct double orientation of crystals. This biaxial orientation in the drawn films has a high degree of correlation with the orientation of crystal axes observed before necking, and suggests that necking takes place in such a way that the chain tilts gradually about the b axis and ultimately unfolds. The postulate of formation of transitory two-dimensional crystals in necking seems useful in explaining the double orientation in the drawn film. The orientation behavior of crystal axes observed before necking is not always similar to that observed in the deformation of a single crystal. The difference is thought to be due to the effect of forces induced by drawing that act in the direction normal to the lamellae within a mat.

On the thickening of lamellar crystals during isothermal crystallization

Abstract: Two theories on the mechanism of the thickening of chain-folding lamellae occurring during isothermal crystallization are conflicting. One attributes the thickening to an annealing process by which isothermal crystallization should be accompanied. An alternative explanation proposed by the author in the preceding paper, was that the effect should be due to molecular fractionation during crystallization. In order to clarify which of the two conflicting theories is preferable, x-ray long spacings were measured for carefully fractionated polyethylene samples crystallized isothermally and quenched after varying time intervals. In contrast with the previous observation made by Hoffman and Weeks at the crystallization temperature, much less thickening was observed for these samples as compared with the unfractionated polymer (Marlex-50). The effect of crystallization temperature on the thickening behaviour was also examined. Again in favour of the fractionation theory the total amount of the thickening observed decreased remarkably with the decreasing temperature. Further, according to the above two theories the distribution of the fold lengths in the crystals formed was calculated as a function of time for the crystallization of the Marlex-50 polymer. Comparing the results of the calculations with experimental data obtained so far, it has been pointed out that the experimental results afford an evidence in favour of the fractionation theory. A possible effect of an amorphous surface layer on the individual lamella on the observed long spacing increase is also discussed briefly.

Rate of ammonium sulfite oxidation in aqueous solutions

Abstract: The rate of the homogeneous reaction of dissolved oxygen and ammonium sulfite in aqueous solutions without catalysts, which has industrial importance in recovery of sulfur dioxide, was studied at 2O, 25 and 3O °C. A polarographic method using a platinum microelectrode was employed for the determination of the oxygen concentration during the course of reaction. Two reactors of different size, which contained O.5 and 4.7 l of solution, respectively, were found to give essentially the same results. The rate of ammonium sulfite oxidation was found to be about one tenth of that of sodium sulfite. The influence of impurities on the rate was found very remarkable. The existence of inhibitors suggested that the reaction might be a radical one. An empirical rate equation, r=k[SO32-]3/2[O2]0[H+]2 in M•min-1 with k= 1.6× 1039exp(-35× 103/RT), was obtained in the experimental range of this work.

Crystallization of A-B-A type block copolymers of poly(ethylene oxide) and poly(α-methyl styrene) from dilute solutions†

Abstract: In order to examine the possibilities of a heterogeneous fold structure proposed previously, in which large irregular loops are incorporated in regular sharply reentrant folds on the surface of polymer single crystals and of the molecular ties which connect lamellae in multilayer crystals, the morphologies of the solution grown crystals of the A-B-A type block copolymers of poly(ethylene oxide) (A) and poly(α-methyl styrene) (B) have been studied mainly as a function of polymer concentration. The range of the content of polyethylene oxide (PEO) was from 0.551 to 0.860, the molecular weight of each sequence being in the order of 104 to 105. The solvents used were ethylbenzene, xylene, and isoamylacetate. It was found that the copolymers having the PEO contents beyond 0.643 crystallized from dilute solution (0.1 to 0.25%) into the form of square tablets, similar to the PEO single crystals. Electron micrographs of these crystals revealed that poly(α-methyl styrene) chains were excluded from the crystalline part and deposited on the surface of the crystals during chain-folding crystallization and long loops thus formed aggregated in the solution or on drying the crystals in a manner depending on the solvents used. When the polymer concentration was increased to 0.5%, irregularly shaped, multilayer crystals were formed where a number of holes were found on their surfaces, suggesting that the frequency of the formation of tie molecules increased rapidly with increasing concentration. Evidences have been supplied for the formation of the long loops on the surfaces of lamellar crystals and of inter-lamellar tie molecules in the chain-folding crystallization. Die morphologische Beschaffenheit von losungskristallisierten A-B-A-Blockcopolymeren aus Polyathylenoxid (A) und Poly-α-methylstyrol (B) wurde hauptsachlich als Funktion der Polymerkonzentration untersucht. Damit wurde die Moglichkeit einer bereits fruher vorgeschlagenen, heterogenen Faltstruktur gepruft, in der grose, unregelmasige Kettenschlaufen in regelmasige, strenge Falten an der Oberflache von Polymer-Einkristallen eingebettet sind. Ferner wurden Untersuchungen uber die durchgehenden Molekule angestellt, die die einzelnen Schichten in mehrschichtigen Kristallen miteinander verbinden. Der Gehalt an Polyathylenoxid (PEO) lag zwischen 0,551 und 0,860, wobei das Molekulargewicht jeder Sequenz die Grosenordnung 104 bis 105 hatte. Als Losungsmittel wurden Athylbenzol, Xylol und Isoamylacetat benutzt. Es wurde gefunden, das die Copolymeren mit einem Polyathylenoxidgehalt von 0,643 aus verdunnter Losung (0,1- bis 0,25-pros.) in quadratischen Plattchen kristallisieren, ahnlich denen der Polyathylenoxideinkristalle. Elektronenmikroskopische Aufnahmen dieser Kristalle zeigten, das die Poly-α-rnethylstyrol-Ketten aus dem kristallinen Teil ausgeschlossen und wahrend der Kristallisation auf der Oberflache der Einkristalle abgeschieden werden. So bilden sich laoge Sehlaufen, die in der Losung oder beim Trocknen der Kristalle aggregieren, je nach den angewandten Losungsrnitteln. Wenn man die Konzentration des Polymeren auf 0,5% erhoht, bilden sich unregelmasig geformte, mehrschichtige Kristalle, an deren Oberflache eine Anzahl von Lochern gefunden wird, was zur Annahme fuhrt, das die Haufigkeit des Vorkommens von Molekulen, die mehrere Schichten miteinander vernetzen, rasch mit ansteigender Konzentration steigt. Es werden experimentelle Unterlagen fur die Bildung von langen Schlaufen auf der Oberflache der lamellaren Kristalle und von molekularen Verbindungen zwischen den ein-zelnen Lamellen bei der Kettenfaltungskristallisation geliefert.