Showing papers by "Japan Atomic Energy Research Institute published in 1969"
TL;DR: The temperature dependence of the electric field gradient (EFG) at the sodium site has been determined in the ferroelectric and paraelectric phases of NaNO 2, where the existence of the antiferroelectric phase can not be evidenced from the present study as mentioned in this paper.
Abstract: The temperature dependence of the electric field gradient (EFG) at the sodium site has been determined in the ferroelectric and paraelectric phases of sodium nitrite (NaNO 2 ). Special attentions have been paid to the narrow temperature range near the ferroelectric Curie point T c where the antiferroelectric phase had been discovered. The main results obtained are: (1) the field gradient varies linearly with the square of the long range order parameter determined by the X-ray study in the ferroelectric phase; (2) a small, but abrupt, change at T c in the field gradient fives an evidence for a phase transition of the first kind; (3) the existence of the antiferroelectric phase can not be evidenced from the present study;(4) slight anomalies exist at 168°C and 178°C in the temperature variation of the field gradient; and (5) the field gradient decreases linearly with increasing temperature in the temperature ranges between 168°C and 178°C and also between 180°C and 230°C. It has been shown that these unusua...
44 citations
TL;DR: In this article, the low frequency dielectric constant of thiourea was measured along the b-direction in the temperature region from 25°C to -120°C at various hydrostatic pressure up to 7 kbar.
Abstract: The low frequency dielectric constant of thiourea was measured along the b -direction in the temperature region from 25°C to -120°C at various hydrostatic pressure up to 7 kbar. The pressure-temperature phase diagram was obtained. The initial pressure coefficients for the V-IV transition temperature (-72.0°C), the IV-III transition temperature (-94.0°C), the III-II transition temperature (-96.8°C) and for the II-I transition temperature (-103.0°C) are -19±2°C kbar -1 , -34±1°C kbar -1 , -31±1°C kbar -1 and -26±1°C kbar, respectively. the V-VI transition pressure, which is 3.3 kbar at room temperature, decreases with lowering temperature. The phase VI is not identical with any of low temperature ferroelectric phases.
37 citations
TL;DR: In this article, a general purpose pulse shape discriminating circuit and its applications are described, which is based on a risetime to pulse height converter which can measure, independently of its input pulse height, an arbitrary fraction of the risetime of the input pulses.
33 citations
TL;DR: The energy dependence of the nuclear level density of Ni, Cu, As, Br, Sr, Y, Nb, Sn, Sb, I, Cs, Ba, La, Ce, Pr, Ho and Bi in the energy range 2.5 MeV was measured from inelastic neutron scattering.
30 citations
TL;DR: A spectrophotometric method is described for the determination of 2-80 mug of ruthenium and about 98 % of (106)Ru tracer was recovered.
25 citations
Patent•
25 Mar 1969TL;DR: In this article, a pulse shape discriminating circuit comprising an input terminal for receiving an input signal, a plurality of characteristic circuits having their inputs connected in common to the input terminal, first and second amplitude discriminating circuits each receiving shaped pulses from the characteristic circuits associated therewith, and a mixing circuit for combining the pulses from said first and Second Amplitude discriminating circuits.
Abstract: A pulse shape discriminating circuit comprising an input terminal for receiving an input signal, a plurality of characteristic circuits having their inputs connected in common to said input terminal, first and second amplitude discriminating circuits each receiving shaped pulses from the characteristic circuits associated therewith, and a mixing circuit for combining the pulses from said first and second amplitude discriminating circuits. The first amplitude discriminating circuit generates a first step pulse representative of the time which corresponds to a first point on said input signal, said first point having a value equal to a first preselected percentage of the peak value of said input signal, the second amplitude discriminating circuit generates a second step pulse representative of the time which corresponds to a second point on said input signal, said second point having a value equal to a second preselected percentage of the peak value of said input signal, and the mixing circuit generates a rectangular pulse waveform having width equal to the time interval between said first and second points.
23 citations
22 citations
TL;DR: In this paper, a phase transition in ferroelectric NaNO 2 was found at -95°C from precise measurements of thermal expansion and low frequency dielectric constant, where a slight break exists both in dielectrics constant vs. temperature and in thermal expansion vs.
Abstract: A phase transition in ferroelectric NaNO 2 is found at -95°C from precise measurements of thermal expansion and low frequency dielectric constant. At this transition temperature, slight break exists both in dielectric constant vs. temperature and in thermal expansion vs. temperature curves. Below the transition temperature, the room temperature ferroelectric phase transforms to a high pressure phase which exists above 8 kbar at room temperature.
19 citations
19 citations
TL;DR: In this article, two different techniques are proposed as the methods for definite observation of the dislocations of NaF single crystals, and the phenomena related to slip, climb and precipitation in the early stage are discussed.
Abstract: Several states of dislocations in nominally pure NaF single crystals are identified by means of two different techniques. The electrolytic coloration is caused by formation of metal Na colloidal particles, which decorate dislocations in the NaF. The chemical etchings, with two different etchants, reveal the dislocations of different characteristics. The two techniques are proposed as the methods for definite observation of the dislocations. The phenomena related to slip, climb and precipitation in the early stage are discussed in connection with the observed dislocations.
18 citations
TL;DR: In this article, the electrical resistivity of 99.999% purity Cu and Au and Au-0.1% Cu alloy was studied after fast neutron irradiation at liquid He temperature.
Abstract: The recovery of the electrical resistivity of 99.999% purity Cu and Au and Au-0.1% Cu alloy was studied after fast neutron irradiation at liquid He temperature. The damage production rate decreased by cold work and alloying in Au, but it increased by cold work in Cu. Cold work enhanced the recovery above 150°K in Cu and above 50°K in Au. In Au, the stage III recovery shifted by about 30°K toward lower temperature for cold worked specimens.
TL;DR: In this article, the time at leading-edge of pulses from radiation detectors is estimated by using two input shaping networks and an amplitude comparator with a fixed time almost independent of the input pulse height.
TL;DR: In this paper, the ordering energy of mixed valence-type oxides is estimated based on the electronic ordering mechanism and by considering the energy of crystalline distortion, and it is shown that ordering energy is proportional to the activation energy of hopping conduction in low temperature phase.
TL;DR: In this article, the phase transition in U4O9 at about 80°C is not considered to be ascribed to dielectric origin, and the dielectrics of UO9 and UO2 increase with temperature increases.
TL;DR: In this article, the authors examined the absorption spectra of single crystals of lithium fluoride having been irradiated with deuterons or protons at liquid nitrogen temperature and found that a band was observed at 542 nm in addition to the F and M bands.
Abstract: Single crystals of lithium fluoride have been irradiated with deuterons or protons at liquid nitrogen temperature. In absorption spectra of the crystals immediately after irradiation, a band is observed at 542 nm in addition to the F and M bands. This band has an almost constant intensity during warming from LNT to RT. It is obscured by the other overlapping bands when the crystal is heated about 100°C or when this is aged at RT for a long time. The nature of this band is examined in connection with the so-called N 2 band, Farge's I band and Vander Lugt's N c band. The following relation is believed to be most plausible: The observed absorption band is identified with the I band. The N 2 band is identified with the N c band but may not be identified with the I band.
TL;DR: The isochronal annealing studies of electrical resistivity of Fe after fast neutron irradiation at liquid helium temperature were performed in this article, where the main peak in stage I was divided into two substages and stages II and III recovery seemed to be influenced by interstitial impurities.
Abstract: The isochronal annealing studies of electrical resistivity of Fe after fast neutron irradiation at liquid helium temperature were performed. Recovery spectra of annealed, cold worked and as-received specimens were compared. The main peak in stage I was divided into two substages and stages II and III recovery seemed to be influenced by interstitial impurities.
TL;DR: In this paper, the half-lives of 80m Br were investigated and they were shown to be 4.42±0.01 h. and 16.8± 0.1 min, respectively.
Abstract: Decay of 80m Br was investigated. The half-lives of the isomeric and the ground states of 80 Br were obtained to be 4.42±0.01 h. and 16.8±0.1 min, respectively. Beta-ray, gamm-ray and gamma-gamma coincidence studies were carried out and energies and relative intensities of beta and gamma transitions were determined. Kurie plot analyses of negatrons and positrons give the maximum energies of 2.000±0.016 MeV and 0.850±0.007 MeV, respectively. The 1.478 MeV 0 + level of 80 Se and the 1.320 MeV 0 + and 1.256 MeV 2 + levels of 80 Kr were confirmed.
TL;DR: In this paper, the blocking effect of energetic particles in single crystals was applied to the 28Si(p, p′)28Si∗, 70Ge(p/p′)70Ge∗ and 72Ge(m, p/m′)72Ge ∗ reactions for germanium.
TL;DR: In this paper, the decay of 1.6 min 185mW and 49 min 185Ta have been studied with Ge(Li), Si(Li) and Si surface barrier detectors, and the conversion coefficients and multipolarity assignments for the transitions between the low-lying excited states of 185W were obtained.
TL;DR: Dioctyl phthalate aerosols, of narrow size distribution with the logarithmic standard deviation of 0.08–0.12 over the range of particle diameter, were prepared reproducibly by means of an improved Sinclair-La Mer generator and the dependence of the size distribution on the generating conditions was studied in detail.
TL;DR: In this article, the ground-state transition width of the 7368-keV resonance level was measured by means of an unclear resonant scattering experiment carried out of the lead capture gamma rays from natural zinc.
Abstract: A unclear resonant scattering experiment was carried out of the lead capture gamma rays from natural zinc. The ground-state transition width of the 7368-keV resonance level was measured by means of...
TL;DR: In this article, the radiation-induced polymerization of glass-forming systems containing vinyl monomers was investigated, and differential thermal analysis was carried out to estimate the second-order transition temperature (Tg) and to follow the postpolymerization.
Abstract: The radiation-induced polymerization of glass-forming systems containing vinyl monomers was investigated. Irradiation below the secondorder transition temperature (Tg) of the systems causes no in-source polymerization but does cause a very rapid postpolymerization in the course of heating above Tg. Differential thermal analysis was carried out to estimate Tg and to follow the postpolymerization.
TL;DR: Differential cross sections for elastic and inelastic scattering of neutrons from iron, nickel and tungsten have been measured with a time-of-flight spectrometer.
TL;DR: In this paper, a new formulation of the noise spectra in at-power reactors is presented, which is based on a set of macrostochastic variables characterizing the state of the reactor possesses Markoffian property.
Abstract: A new formulation of the noise spectra in at-power reactors is presented. Input noise source is determined in such manner that ready comparison is possible between the, square modulus of the reactor transfer function and the noise spectrum. The physical meanings of the noise-equivalent source are clarified. A new noise source additional to that of zero-power reactors is found, which results in a non-white contribution to the input noise source spectrum. The basis of the present theory is a set of macrostochastic variables characterizing the state of the reactor possesses Markoffian property. Three types of reactions are taken into account—source emission, linear and bilinear reactions.
TL;DR: In this paper, the γ-radiolysis of aqueous boric acid solutions of relatively high concentration has been studied, and it was shown that NO− 2 reacts with H3BO3 or H2BO3 radicals, the plausible reaction product from the reaction H 3BO3+OH →; H2O+H2BO 3.
Abstract: The γ-radiolysis of aqueous boric acid solutions of relatively high concentration has been studied. Boric acid significantly promotes hydrogen formation up to 10−7 mol/ml but does not increase oxygen and hydrogen peroxide to any appreciable extent. Since boric acid reacts at a relatively slow rate with species formed by the primary process of water radiolysis, when an effective scavenger for e − aq—the precursor of H2—such as NO− 3 is present, boric acid has no effects upon the total yield of H2 in the range of concentrations studied. However, the yields of other products of the radiolysis—H2O2 and NO− 2—are significantly reduced at high concentrations of boric acid when NO− 3 is present. These results are explained by established reaction schemes for the radiolysis of aqueous solution. Based upon the behavior of NO− 2 from nitrate solutions, it is suggested that NO− 2 reacts with H3BO3 or H2BO3 radicals, the plausible reaction product from the reaction H3BO3+OH →; H2O+H2BO3.
TL;DR: In this paper, the temperature effects of planar channeling of 1.5 MeV protons for silicon thin crystal were investigated and the results showed that the low loss component (channeling peak) in energy spectrum of transmitted protons decreases with increasing temperature and its energy value does not change.
TL;DR: In this article, the authors measured the IR spectra of normal and deuterated KD 2 PO 4 in the regions 500 and 1000 cm −1 at various temperatures, and concluded that above the Curie point each H atom moves in a potential with a flattened bottom in KD 2PO 4 and each D atom is in a symmetrical double minimum potential in KD PO 4.
TL;DR: In this paper, the higher order perturbation theory is applied to the one-dimensional multi-group diffusion equation and the method of calculating the eigenvalue, eigenfunction and adjoint function of the higher mode is established for a non-Hermetian matrix.
Abstract: The higher order perturbation theory is applied to the one-dimensional multi-group diffusion equation. The method of calculating the eigenvalue, eigenfunction and adjoint function of the higher mode is established for a non-Hermetian matrix. The diffusion equation is solved by the higher order perturbation method, through the use of the eigenvalues, eigenfunctions and adjoint functions of the higher modes. The newly developed method is applied to the estimation of reactivity effect in a reactor.
TL;DR: In this article, a gas recoil fast neutron spectrometer of thick radiator type was constructed and its performances were investigated, which was composed of three methane-filled proportional counters arranged longitudinally with one common center wire.
TL;DR: In this article, conditions for the virtually complete extraction of uranium from aqueous solution are described, and various factors which influence the extractibility of URE from a ureous uranyl solution with sodium amalgam have been investigated.