Mutual Phase Research Articles

Phase-locking characteristics of coupled ridge-waveguide InP/InGaAsP diode lasers

The phase-locking characteristics of two coupled, ridge waveguide InP/InGaAsP diode lasers emitting at 1.2 μm were investigated experimentally. The phase locking of the lasers was verified by the observation of phase-locked modes (supermodes) in the spectrally resolved near fields and distinct diffraction patterns in the far field. By independent control of the laser currents it was possible to vary continuously the mutual phase shift between the two phase-locked lasers and thus steer the far-field diffraction lobes. In addition, the separate current control could be utilized to obtain single longitudinal mode oscillation of the phase-locked lasers. Variation in one of the laser currents resulted then in tuning of the wavelength of this single mode over a range of 90 Å.

Mutual phase locking of a coupled laser diode-Gunn diode pair

Mutual phase locking has been achieved through series connection of a semiconductor laser and a Gunn diode oscillator. Experimental results obtained demonstrate a mutual interaction between the two oscillators which results in a short term Gunn diode oscillator stability and improved spectral purity of its output. We also observe a narrowing of laser pulses and an improvement in regularity.

On the ordered structure of poly(butylene terephthalate) in polyester blends

AbstractSome unusual x‐ray diffraction results have been obtained corresponding to an ordered structure in binary blends of a poly(butylene terephthalate) (PBT) with a polyarylate. The polyarylate is a noncrystallizable copolyester of bisphenol‐A with a 50–50 mix of terephthaloylisophthaloyl units. The two polyesters have been previously found by us to be compatible in their mutual amorphous phase. The x‐ray data are shown to be consistent with a nematic order for the PBT in the blends.

Influence of diffusion and of phase equilibrium in elastomer-phenol-formaldehyde oligomer systems on the strength of adhesive bonds

Mutual diffusion processes and phase transitions in phenol-formaldehyde oligomer (PFO)-elastomer systems have been investigated at various stages of cure of PFO during the formation of adhesive bonds. The distribution of components in the adhesion contact zone has been determined. It is shown that the cure of the PFO fixes the concentrational distribution at the stage of diffusion mixing of the components. The results of electron-probe X-ray microanalysis of the adhesion contact zone between PFO and butadiene-nitrile elastomers show that phase transitions occur in this zone, and result in formation of structure that provides the bond strength. A mechanism of formation of adhesive bonds is proposed for partially compatible components.

Analysis of a PLL system as analog processor in CW Doppler flowmeters.

In this paper a phase-locked loop (PLL) system is analyzed in order to evaluate its performance for estimating the average frequency of an input spectrum made up by Ndiscrete components allocated in a frequency interval B. The system was studied first in the simplified case that the phase comparator has a linear characteristic. Next, a computer-aided simulation of the PLL system was performed taking into account the nonlinear characteristic of the phase comparator, assuming that the input spectral components have mutual random phase in (-?, + ?) interval and amplitudes with a distribution either uniform or obtained from a particular parabolic velocity profiles.

Control of mutual phase locking of monolithically integrated semiconductor lasers

The mutual coherence of two coupled semiconductor lasers is investigated experimentally. It is demonstrated that by varying the gain in the overlap region, the degree of phase coherence can be continuously controlled. The quantitative characterization of the degree of phase coherence by fringe visibility is demonstrated.

天然産マンガンスピネノレ系鉱物の諸問題

Manganese spinel minerals reported till now include hausmannite, iwakiite, Jacobsite, galaxite, hetaerolite, manganochromite and vuorelainenite. The first four minerals occur commonly in the bedded manganese deposits formed in Paleozoic to Mesozoic sediments of Japan. Their mutual phase relations are usually considered in the ternary system Mn3O4-MnFe2 O4-MnAl2O4. The immiscibility range between jacobsite and galaxite in the system MnFe2O4-MnAl2O4 disappears with increasing Mn3O4 content in their solid solutions at metamor. phic temperature and an extensive jacobsite∼galaxite complete solution becomes to exist with another restricted hausmannite solution in the ternary system. Jacobsite also has extensive solution with Mn2TiO4 and the Mn2TiO4 content of the solution attains to about 70 mole % in the metamorphosed deposits. Consequently jacobsite solution needs to be treated in the quarternary system Mn3O4-MnFe2O4-MnAl2O4-Mn2TiO4. Iwakiite, Mn (Fe, Mn)2O4, has the only extensive solution with Mn2TiO4 in the quarternary system but its stability relation is unknown because it never coexist with any other spinels and has not been synthesized. This mineral must hold the keys to decipher the complex phase relations in this system.

Characterization and gas permeation of polycarbonateliquid crystal composite membrane

Polymer/liquid crystal composite membranes were cast from a 1,2-dichloroethane solution of polycarbonate (PC) and N-(4-ethoxybenzylidene-4'-n- butylaniline) (EBBA). The mixing state of the polymer/liquid crystal composite membrane was investigated on the basis of differential scanning calorimetry, x-ray, density, sorption isotherm and sorption—desorption studies and also by electron microscopic observations. EBBA molecules in the composite membrane exist in an almost molecularly dispersed state up to an EBBA fraction of 30 wt%, and in the case of EBBA fractions above 30 wt% form a crystal domain as the mutual continuous phase among the network of polycarbonate fibrils. The composite membrane containing EBBA of 60 wt% can be handled as a homogeneous medium when considering gas permeation. The diffusive permeability coefficient to water reveals a distinct jump in the vicinity of the crystal—liquid crystal phase transition temperature of EBBA. The permeability coefficients, P, to hydrocarbon gases increases 100-200 times over several degrees in the phase transition temperature range. P for hydrocarbon gases decreases with increasing number of carbon atoms below the phase transition temperature, but increases with increasing number of carbon atoms above it. These results suggest that the permeation process is predominantly controlled by diffusion mechanism below the transition temperature of EBBA, while the solubility factor significantly affects gas permeation above it.

Backreflection-induced oscillations of the intensity of radiation emitted by a single-frequency cw dye ring laser

When a certain critical intensity is exceeded, backreflected signals produced by counterpropagating waves with a definite mutual phase shift give rise to oscillations of the intensity of the radiation emitted by a ring laser with a homogeneously broadened line. Measurements are reported of the critical reflection coefficient and of the dependence of the oscillation frequency on the intensity of backreflected signals in the case of a single-mode cw dye ring laser. The experimental results are in good agreement with theoretical predictions. It follows also from these results that a cw dye ring laser can be used as a tunable source of modulated light with a small band width, a depth of modulation of about 100%, and a modulation frequency variable from a few hundreds of kilohertz to approximately 20 MHz.

Ferroelastic phases in Pb3(PO4)2–Pb3(AsO4)2; X-ray and optical experiments

Mixed crystals Pb3(PO4)2--Pb3(AsO4)2 are ferroelastic at low temperatures. The phase diagram contains three different phases a (paraelastic), \tt b and \tt c (both ferroelastic). The transformation \tt a-\tt b is first order for Pb3(PO4)2 and approaches second-order behaviour with increasing As content. The spontaneous strains and the birefringence follow approximately a Curie-Weiss law, with a corresponding order-parameter exponent β = ¼. The mutual high-temperature phases give diffuse X-ray reflections due to inelastic scattering. The soft-mode model is discussed for these results.

Mutual phase locking in multijunction Josephson arrays

Mutual phase locking of Josephson oscillations in a two-junction cell and multijunction arrays is analysed. The locking is due to ac currents of Josephson frequency ω, which flow through some special coupling circuit. For the most important case of almost identical junctions, the locking frequency range is shown to be proportional to the imaginary part of the complex conductivity Y(ω) of the coupling circuit. The power and linewidth of coherent oscillations, as well as the coherence stability with respect to the junction intrinsic noise and parameter spread, have been calculated. The maximum locking range and, hence, the maximum parameter tolerances are shown to take place in the closed-loop-type (ring) structures with long-range junction interactions.

A new class of medium-size high-efficiency reflector antennas

The new class of reflector antennas that is described in this communication yields a higher directive gain than obtained with conventional reflector antennas of the same area. An antenna of this new design consists of a reflecting surface, a peripheral rim, and a feed system in the reflector center. It is analyzed as a combination of two radiating sources whose radiation maxima and mutual phase relations can be simply adjusted for highest directive gain in the axis normal to the reflector. The marked directive gain increase is explained on the basis that there is a virtual extension of the radiating aperture beyond the physical dimensions of the reflector. The two antenna models that are described develop directive gains of almost 3 dB above those of conventional reflector antennas of equal size and comparable pattern characteristics. Optimized for a given frequency, the new design covers a pattern bandwidth of approximately 4:1.

Intensity Fluctuations in a Stochastic Medium

A representation of the ocean medium as a stack of very thin isosound velocity layers, stochastic in a part of their sound velocity, has been used to calculate the statistics for sound-intensity variation without introducing a random phase approximation. A model previously introduced [N. W. Lord, J. Acoust. Soc. Amer. 46, 111 (1969)] to calculate transmission-time statistics was extended first to treat intensity of discrete arrivals, quantitatively including phase differences among microarrivals, and second to accumulate at discrete range points all discrete arrival contributions similarly calculated and quantitatively including their mutual phase differences. Both discrete arrival intensities and accumulated or CW intensities show a Poisson-like distribution with standard deviation being equal to the mean for moderate sound velocity variance in rough agreement with existing data.

THE ROLE OF SURFACE ENERGY OF ADHESION IN METAL WORKING

The concept of surface energy of adhesion can be applied in a number of ways to reduce friction during metalworking operations. Theoretical considerations suggest that the die material should be insoluble in the workpiece material, as indicated by the mutual phase diagram. If a liquid lubricant is used, then it should either form a solid surface film or have a high surface energy and wet the die and workpiece. A solid lubricant should have either a low shear strength or a low surface energy and a thickness in the range 10‐6‐10‐2 cm. The paper describes how these requirements are met in practice.

Contribution to the theory of rotary jet flow induction.

Rotary jet flow induction is studied with a refined analytical flow model. The mutual deflection of primary and secondary flow takes place in a ring-shaped interaction region of finite thickness and curvature. The mutual flow deflection phase is accompanied by jet dissipation and is followed by constant area mixing of the two Hows. The refined analytical method yields optimum values for certain geometric and operational characteristics that could not be deduced from earlier types of analysis and that agree with model test results. Performance improvements of the rotary jet flow inductor, as compared to the ejector with equal flow cross sections, are particularly significant if, at the primary nozzle exit, the primary flow has a much lower density than the secondary flow. This condition can be achieved either by using different gases for primary and secondary flow or, in the case of identical gases, by heating the primary 60 w.

Fundamental properties of non-linear focusing

An analysis has been made of the fundamental properties of non-linear focusing taking the simple example of non-linear focusing in a symmetric magnetic field of the fifth degree. The dimensions of the first stability region with regard to small non-linear z-oscillations are determined. The influence of r-z-resonances was studied and also the maintenance of stability when allowing for adiabatic damping with the help of external or mutual r- and z-phase stabilization. It was found that mutual phase stabilization arises in the region of a r-z-resonance. A numerical and partly analytical study of these effects has been made.

Polytypes of the phlogopite-biotite series and their mutual relations

Chemical compositions and polytypes of twenty specimens of trioctahedral micas from various occurrences of the phlogopite-biotite series have been determined. The results (Tables 1 and 2) are as follows: 1) Almost all of the phlogopites and biotites in basalts and andesites are 1M type. 1M type biotite transforms to 2M type biotite (anormite) by the oxidation reaction, Fe2+(OH)-→Fe3+O2-+H↑. 2) Most biotites in granites and granodiorites are 3T type and a few 3 Td or 1M type. 3) In gneiss as compared with gneissose granodiorite, 3T type decreases and 3Td or 1M type increases. 4) The biotites in pegmatites are 1M or 3 Td or 3T type. 5) The biotites and phlogopites in quartz-biotite schists and in the skim zone of contact deposits are almost 1M type.In the synthesis of phlogopite and muscovite, at low temperatures the nucleation of 1Md type mica takes place easily, and so does the nucleation of 1M type mica at temperatures above 500°C. In the hydrothermal treatments of natural phlogopite and biotite, lMd type micas transfrom to 1M type, and 3Td type and 1M type micas transform to 3T type. In the basis of these experimental results, the mutual phase relations of polytypes of trioctahedral micas of the phlogopite-biotite series have been discussed and figured as in figures 3 and 4.

Researches of the Saturabled Mutual Induction Type Automatic Phase Shifter

Researches of the Saturabled Mutual Induction Type Automatic Phase Shifter

Hippocampal seizure states in guinea pig

1. 1. The electrical activity of hippocampus and isocortex in unanesthetized guinea pigs during resting state and in response to external stimulation is described. It is shown that there is a differential response of hippocampal and isocortical activity to complex environmental stimuli. 2. 2. Mechanical and electrical stimulation of the hippocampus induce local and propagated seizure discharges at relatively lower thresholds than stimulation of isocortex, striatum and thalamus. 3. 3. The structure of the hippocampal seizure discharge as analyzed from combined ink-writer and cathode-ray oscillograph recordings is a composite of several activities of different frequency orders with relatively constant mutual phase relationships. In particular, the clonic stage is characterized by slow pulses of 0.3 to 5 c/sec., with super-imposed waves of 10–30 c/sec., carrying on top of them brief spikes of 2–5 msec. duration. Each of these complex pulses is preceded by a shower of 100–200 c/sec. spikes. Periods of apparent silence are characterized by a deviation of the basic potential from the iso-electric line, of opposite polarity to the one exhibited during the clonic pulse. Gross spikes and spike-and-waves appearing at the onset of a “tonic-clonic” afterdischarge are rarely observed in the hippocampus but are common in the epileptic activity of neocortex, striatum, amygdala and thalamus. 4. 4. Hippocampal afterdischarges spread widely over cortical and subcortical structures, as well as over the cerebellum. They show a preferential spread over the centrocaudal isocortex, often avoiding the rostral neocortex. 5. 5. Unless unduly strong stimulation, resulting in a grand mal convulsion, is applied, there are only slight changes of behavior concurrent with the after-discharge: arrest of ongoing behavioral activity and decrease of reflex responses. 6. 6. These various findings suggest that the hippocampus may play an important role in epilepsy in general. This structure may participate in, and may indeed initiate the manifestation of those forms of epilepsy which are chiefly characterized by disturbances of awareness and mental confusion.

Dielectric-loss-measuring equipment for field and works testing

The paper describes two new direct-reading methods which have been developed for the measurement of dielectric power factor, with particular reference to the field and works testing of high-voltage insulation. The two methods to some extent resemble the Schering bridge in that they incorporate a low-loss condenser of known capacitance and negligible loss angle, as the standard with which the insulator under test is compared, but differ radically from the bridge in the manner in which the comparison is effected.The essential feature of the first method is the production of a series of unidirectional voltage pulses of rectangular waveform and constant amplitude, and of the same frequency as the supply. The circuit is so arranged that the duration of each pulse, and, in consequence, the mean value of the resulting voltage, is directly proportional to the insulator loss angle δ. The final indication of loss angle (or, what is virtually the same thing since δ is small, the power factor sin δ), is either given directly on a calibrated voltmeter, or estimated approximately by visual examination of the pulse waveform on an oscillograph screen.The second method consists essentially in using the difference between two voltages, of equal amplitude but with a mutual phase difference equal to the insulator loss angle, as a measure of the power factor, the latter being indicated directly on a calibrated voltmeter. The particular point of interest about this method lies in the means adopted for the preliminary adjustment, which must be made to ensure that the amplitudes of the two voltages are exactly equal.