Angular correlations of the 609–320 keV gamma ray cascade in ⁵¹V and of the 833–1039 keV gamma ray cascade in ⁶⁶Zn have been measured using a multicounter goniometer. In the case of ⁵¹V the correlation function is W(θ)=1+(0.075±0.024)P₂ (cosθ)−(0.029±0.028)P₄ (cosθ), which is compatible with δ₆₀₉=0.14 or −6.5 for the spin sequence of 3/2–5/2–7/2. In the case of ⁶⁶Zn the correlation function is W(θ)=1+(0.30±0.05)P₂ (cosθ)+(0.21±0.07)P₄ (cosθ), which gives 1.57≤δ₈₃₃≤2.27 for the 2(D, Q)2(Q)0 sequence. The relative intensity ratio between the assumed crossover 1872 keV gamma ray and the 1039 keV gamma ray should be less than 5×10⁻⁵. A new 1333 keV gamma ray was found in ⁶⁶Zn. The relative intensity of it to the 1039 keV gamma ray was determined to be 4.3×10⁻⁴.

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Angular correlations between two alpha particles emitted from the reaction B¹¹+α→α+α+Li⁷ are studied at the incident energy of 28.5 MeV. The kinematics of the final state were completely determined by measuring the momenta of two alpha particles detected in coincidence. The reaction cross sections are dominated by two body interactions between two alpha particles and between alpha particle and Li⁷ nucleus. Interferences among two body interactions are observed at the overlapping of two body resonances. This is discussed to be due to the fact that three bodies interact in the final state.

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A new general formulation for calculating the wave-number dependence of plasmon damping in metals, including the effects of both the electron-electron and the electron-ion interactions, is presented. As an important application of the general formalism, the case of an electron gas is investigated. The detailed calculation of the probabilities of plasmon decay by producing two electron-hole pairs is made. The effects of exchange processes are also investigated. The numerical result for the q² coefficient of the plasmon damping rate is considerably smaller than that obtained by previous theories. The process of plasmon decay via excitation of one electron-hole pair plus another plasmon is shown to contribute a term of q⁶ in contrast with the result of previous theories which predicted it to be of q⁴. The comparison with characteristic energy loss experiments is also discussed briefly.

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The Ornstein-Zernike relation for an n-component fluid mixture is investigated under the assumption that the direct correlation function between two particles of species i and j, c_ij(r), is zero when r is greater than R_ij≡(R_i+R_j)⁄2 (i, j=1, 2, ···, n). The relation is transformed so as to involve the radial distribution function g_ij(r) only for r which is smaller than R_ij (i, j=1, 2, ···, n). The result is applied to a mixture of hard spheres in which R_i, giving the range of the direct correlation functions, is assumed to be the diameter of the hard spheres of species i (i=1, 2, ···, n). The direct correlation functions are found in the explicit forms, which are in complete agreement with those obtained by Lebowitz in case of a binary mixture.

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A simple dynamical model of interacting Ising spins is discussed near the critical point. It is shown that all the moments are positive and never vanish even at the critical point. Lower and upper bounds of the susceptibility are obtained, which yield the non-vanishing of the real part of the susceptibility. This gives a simple proof for the poly-dispersive nature of our system. The method of high temperature expansions for the dynamical susceptibility is presented and is applied to the two-dimensional Ising model up to the ninth order, the results of which show that the critical index of slowing down (the relaxation time τ⁽¹⁾∝(T−T_c)^−Δ; Δ=2±0.05) is different from that of the static susceptibility.

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The Curie temperature of nickel films deposited in ultra-high vacuum was determined by measuring Hall voltage, electrical resistance and magnetoresistance of films as functions of temperature. A fall of the Curie temperature was observed as thickness decreases below 300Å. The Curie temperature of films is independent of substrate temperature during deposition. The effects of impurities on the Curie temperature are also discussed.

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Magnetic susceptibilities of KMg_(1−x)Ni_xF₃ and K₂Mg_(1−x)Ni_xF₄ (0≤x≤0.121) have been measured in the temperature range from 1.6°K to 300°K, and the exchange interactions between neighboring Ni²⁺ ions have been evaluated. The analysis of the data has been made on the assumption that Ni²⁺ ions distribute randomly in Mg²⁺ sites and form various types of clusters coupled by the exchange interactions. In KMgF₃, the nearest-neighbor exchange J₁ is 110±10°K and the next-nearest-neighbor exchange J₂ is 0.5±0.1°K, where an exchange interaction between neighboring spins s_i and s_j is written as J(s_i·s_j). In K₂MgF₄, J₁ is 120±10°K. The intraplane next-nearest-neighbor exchange J₂ and the interplane-nearest-neighbor exchange J₃ can not be determined uniquely, but the most probable values are J₂≅0.5°K and J₃≅0. The Van Vleck paramagnetic susceptibilities of Ni²⁺ in both salts have been found to be 2.83×10⁻⁴ cgsemu/mol within the experimental errors of 10%.

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The effect of magnetic-field cooling was measured on a single crystal of vanadium metal of 99.9% purity using a sensitive torque-magnetometer. It was found that uniaxial anisotropy with the easy axis parallel to the cooling field was induced by the magnetic-field cooling from 300°K down through the anomaly temperature to 87°K with cooling field 13 kOe, and that the induced anisotropy disappeared precipitously when the specimen was heated up to 280°K, which is ascribed to the anomaly temperature of this specimen. It is suggested that the anisotropy is due to the preferably oriented phase of vanadium hydride which has small spontaneous magnetization.

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X-ray diffraction and magnetic studies have been made on the intermetallic compound CoTi. X-ray diffraction studies indicate that Co_1+xTi_1−x with the CsCl-type structure has the single-phase ranging from about 44.5(x=0.110) to 50.0 at. % Ti(x=0). According to magnetic measurements, the stoichiometric CoTi appears to be Pauli paramagnetic, whereas in nonstoichiometric cobalt-excess composition an appreciable increase in magnetic susceptibility is observed at low temperature, which may be attributed to the appearance of magnetic moment in this composition range. The magnetic moment estimated from the observed Curie constant is nearly proportional to x, therefore it may be concluded that the magnetic moment belongs to the excess cobalt atom, which is assumed to be substituted with the titanium atom in the equiatomic composition.

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It was reported in a previous paper that aluminum granular films prepared by means of gas evaporation in helium showed enhanced superconductivity. In the present experiment, a temperature dependence of D. C. electrical resistivities of these films is measured by means of a four contact method. It is found that absolute values of the resistance depend on the film thickness but the most of the films show temperature independent resistivity. These features are interpreted in terms of electronic mean free path and the particle size of the films.

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The low temperature specific heat of orthorohmbically distorted C_c-type La–Ge compounds have been measured in order to investigate the origin of an anomalously small specific heat jump, (Remark: Graphics omitted.), of LaGe₂ at the superconducting transition temperature. LaGe_x has orthorohmbically distorted C_c-type crystal structure in the composition range 2.0≤x≤1.78. For 2.0≤x≤1.85, (Remark: Graphics omitted.) is anomalously small as in LaGe₂. (Remark: Graphics omitted.) approaches the B.C.S. value at x=1.78. In the intermediate range, 1.85<x<1.78, there appears two close specific heat jumps as if samples were of two-phase crystal structure. According to the detailed X-ray study of the crystal structure these curious behaviour of (Remark: Graphics omitted.) seems to be due to some intrinsic origin and a possible model is discussed.

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The Mössbauer effect and the neutron diffraction were measured in disordered Fe₆₃(Ni_1−xMn_x)₃₅ alloys. The Mössbauer effect experiments revealed that the internal field acting on iron nuclei is about 300 kOe in ferromagnetic alloys and changes abruptly to about 45 kOe in antiferromagnetic alloys in which the internal field is nearly independent on concentration. These results are consistent with a previously proposed model that the electronic state of iron atom in the ferromagnetic alloys is considerably different from that in the antiferromagnetic ones. The neutron diffraction experiments indicated the cubic spin structure is these alloys. The sublattice moment was found to be nearly constant from x=1.0 to 0.7 and to decrease sharply at around x=0.6 with decreasing x.

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Intrinsic surface states on clean and perfect surfaces of semiconductors are investigated. Calculations are made for (111) and (100) surfaces of diamond-type crystals, C, Si, Ge and α-Sn, with a tight-binding approximation including interactions up to nearest-neighbor distances. Second-nearest-neighbor approximation is also examined for Si and Ge. Spin-orbit coupling is wholly neglected. For the (111) orientation, two types of surfaces are considered: one intersects one bond per surface atom (denoted as (111)-1) and the other dose three bonds (denoted as (111)-3). It is shown that the surface band structures of the diamond-type crystals are correlated with the shape of the conduction bands and the specific surface energy of the (111)-1 surface is lower than those of the (111)-3 and (100) surfaces. Surface reconstruction is not considered in the calculation but its close relationship with the surface states is discussed.

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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 (NaNO₂). 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 unusual behaviors of the ²³Na field gradient have close relations with the molecular motions of NO₂⁻ ions and the structural changes in the crystal which bring about the phase transition.

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The thermodynamical theory is extended to the hot electron problem and irreversible entropy production is calculated. On the minimum principle of entropy production it is derived that the electron temperature is not uniform in bulk semiconductors, even if the lattice temperature is kept constant.
Instability conditions for the electron density wave is discussed. In the case that the dielectric relaxation frequency is larger than the frequency of the density wave, the instability occurs when the differential conductivity is negative. When the relaxation frequency is smaller than the frequency of the density wave, the instability condition is found to depend on the detailed properties of the system and is not directly related to the static behavior of the conductivity.

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The Hall effect and the resistivity of undoped p-CdSd were measured in the temperature range between 2°K and 300°K, and also the magnetoresistance effect at 2°K and 4.2°K. The anisotropies were observed in the magnitude of the Hall mobility and its temperature dependence. The intermediate type of the impurity conduction occurs in the concentration range between 2.5×10¹⁵cm⁻³ and 1.0×10¹⁷cm⁻³. The remarkable magnetic field dependences of the Hall coefficient and the magnetoresistance were observed at 4.2°K in the intermediate concentration range. The observed magnetoresistance was found to be consist of three components. One is a negative component which saturates at high magnetic fields. The others are two positive components, one of which is due to the change of the activation energy by the magnetic field, and the other is the contribution of two kinds of holes. A negative magnetoresistance was observed at 2°K in samples with the acceptor concentration higher than 2×10¹⁵cm⁻³.

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The emission peak of Mn²⁺ ions in calcium fluoro-chlorophosphates shifts to longer wavelength with a ratio of fluorine to chlorine ions. From optical and EPR experiments, This is explained qualitatively to be due to a change of distribution of Mn²⁺ ions over two non-equivalent calcium lattice sites. The splitting factors were evaluated for both Mn²⁺ ions occupying these calcium sites; for the Mn²⁺ ions in a trigonal field, g_⁄⁄=2.001±0.001, g_⊥=2.000±0.001, D=±(439.6±1.0) gauss, a−F=+7.8±1.0 gauss, A=±(97.6±1.0) gauss, B=±(91.3±1.0) gauss, and for the Mn²⁺ ions in an equivalent orthorhombic field near halogen ions, g=1.999, D=±497.2 gauss, E=±11.7 gauss, A=±88.6 gauss, on the assumption of isotropy in the g-factor.

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Thermal formation of F₂⁺ centers in KCl crystals has been investigated in temperature region between 210°K and 270°K. KCl crystals containing electron traps such as Tl⁺ ions were X-rayed at room temperature and was illuminated with F light at 120°K. Negative ion vacancies thus produced from F centers began to move about 220°K and combined with F centers to from F₂⁺ centers. The activation energy for the F₂⁺-center formation was estimated to be 0.52±0.03 eV. An absorption band at 1.35μ at room temperature was confirmed to arise from F₂⁺ centers and to shift to 1.40μ at liquid helium temperature. The frequency of the lattice vibration influencing the ground state of the F₂⁺ center was 2.9×10¹² cps, which was almost the same value with that of the M center. The F₂⁺-center formation is discussed by assuming the covalent force acting between an F center and a negative ion vacancy.

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The optical absorption spectra of KCl–KI and NaCl–NaI solid solutions in the whole concentration range are presented. Measurements are made in the range from 5.5 eV to 7.5 eV at 80°K. The changes in the profile, the positions of the resolved structures and their intensities in the absorption spectra in changing the concentrations of iodide are observed. With increases of the concentration of I⁻ ions, the localized exciton bands due to cluster of I⁻ ions appear on the low energy tail of those due to an isolated I⁻ ion. Above certain concentration of I⁻ ions, the exciton can be regarded as the band exciton rather than localized one. The percolation theory seems useful for explaining this. Taking account of the band structures in KI and NaI, it is proposed that the absorption bands at 6.69 eV and 7.49 eV in KCl:I and at 6.90 eV and 7.60 eV in NaCl:I are assigned as the spin-orbit pair of the localized exciton band.

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As to the intrinsic luminescence of KI and RbI the correlation of polarization between exciting light and emitted light was measured at 4.2°K. The degree of polarization is zero throughout the energy range of the first exciton absorption band. Further no azimuthal dependence is found. These results are discussed in comparison with the emission from α center in KI, for which polarization correlation was observed. In the case of the intrinsic luminescence, it seems most plausible to consider that exciton state relaxes via some unknown intermediate states to the lowest excited state of the (V_k+e) system to emit the luminescence, and the memory of polarization is lost during this relaxation process.

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The luminescence of pure alkali halide crystals induced by the excitation with UV-light in the fundamental absorption region at low temperature is observed in NaCl, KCl, RbCl, NaBr, KBr, RbBr and KI. In KCl, RbCl and NaBr one emission band, in NaCl, KBr and RbBr two emission bands and in KI three emission bands are induced at 11°K. All of the emission bands, except one in KI, are confirmed to arise from the self-trapped exciton, or the V_k⁻ center. The quantum efficiencies for the luminescence are estimated as small as 0.1 to 0.2 in KCl, KBr and RbCl and a little larger in the other crystals. The excitation spectra and temperature dependence of the intensity of the luminescence are measured and the results are discussed in connection with the properties of the V_k⁻ center.

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Iron single crystals with the [100] and [110] axes were extended at 23°C and −78°C and examined by transmission electron microscopy using thin foils cut parallel to lattice planes. In the initial state of deformation, screw dislocations and edge type loops were observed predominantly. Two-dimensional tangles of dislocations approximately parallel to the slip plane were observed in the further state of deformation in the both crystals deformed at 23°C and in the [110] crystals deformed at −78°C. The relations between the flow stress τ and dislocation density ρ were analysed by the equation τ=τ₀+αGb\sqrtρ. The value of α in the crystals which had uniform distribution of dislocations was larger than that in the crystals which had non-uniform distribution. These results suggest that the work-hardening at low temperature deformation is due mainly to forest dislocations.

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The temperature dependence of the integrated intensity of three Bragg reflections (020), (230) and (211) for polyethylene crystal has been measured in the temperature range from −90°C to 110°C. The temperature factor increases with increasing temperature. The anisotropy of the temperature factor has been obtained from the temperature dependence of the integrated intensity of three Bragg reflections. Below 0°C, the temperature factor is a linear function of temperature and the three components of the thermal average of the mean squared displacement agree with the theoretical values calculated by Kitagawa and Miyazawa using the harmonic approximation. Above 0°C, however, the temperature factor increases with more steep slope and the harmonic approximation is not satisfied. In this temperature range, the anharmonic lattice vibration may cause the increase of the temperature factor.

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By using the rheological equation obtained from the theory of network structure, the expressions of storage and loss moduli are obtained as functions of the chain length. The concentration dependence of storage and loss moduli is obtained theoretically in closed form by investigating the relation between chain length and concentration. The tendency of shift from the Zimm-like behavior to the Rouse-like is explained in terms of the concentration effect on the number of intermolecular junctions, whereas in Tschoegl’s theory it is interpreted in terms of decreasing hydrodynamic effect.
The principal results obtained are as follow.
1. The quantity J_eC⁄(1−v₁⁄η_r)² passes through a maximum and decreases inversely proportional to concentration in moderate concentrations and to the square of concentration in high concentrations.
2. The low shear viscosity is proportional to M^3.5C^3.5 in moderate concentrations and to M^3.5C⁶ in high concentrations.
3. The storage modulus and the loss modulus transform from the Zimm-like behavior to the Rouse-like as the concentration increases.
4. The concentration dependence of storage and loss moduli at fixed frequency is investigate at three fixed frequencies.

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The differential and integrated cross sections for the rotational excitation (0→2 and 1→3) of the hydrogen molecule by show electrons are calculated in the adiabatic approximation. The effects of electron exchange and target polarization on the rotational excitation are investigated. Inclusion of these effects increases cross sections and results in good agreement with experimental data.

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A theoretical analysis of the ionic transport across the lipid membrane is given on the basis of the thin symmetric membrane model with electric change on central plane and compared with the experimental result. The condition of the electric neutrality in the membrane does not stand since the thickness of the lipid membrane, 40–60Å, is too thin to neglect the effect of the ionic atmosphere.
The distributions of the electric potential and ions in the membrane which satisfy Poisson’s equation and the ionic flux equation are taken into consideration.
The increase in the electric conductance of the membrane on addition of the surface active agent can be interpreted as follows.
The added agent to the electrolyte solution is adsorbed on charged plane due to physical adsorption. The charge density of the charged plane changes by this adsorption, and subsequently this charge may affect the electric conductance of the membrane.

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Two groups of dielectric absorption are observed in the impurity (surfactant=metal salt of imidazoline type amphoteric agent) doped high and low density polyethylene. One of them has the loss maximum dependent on the amount of the impurity and is imputed to the relaxation of a dipole orientation of the impurity. Another shows an odd behavior named retrogressing phenomenon near the melting point of polyethylene (90°C for low density polyethylene and 120°C for high density polyethylene) and can not be detected in the amorphous polystyrene depoed with the same impurity. An interfacial polarization is proposed assuming a model, crystalline part of polyethylene being covered with a surfactant dense layer. This model is justified semi-quantitatively by the Miles and Robertson theory. The retrogressing phenomenon is explained by the change of the layer thickness that affects the dielectric relaxation time of this model.

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Ion acceleration of a plasma in a nonuniform magnetic field by an rf field is investigated. The ions are accelerated along the axis of the magnetic line due to the μ∇_⁄⁄B force, where μ is the magnetic moment of an ion of which energy is increased through cyclotron damping of electrostatic ion cyclotron wave and ∇_⁄⁄B is the magnetic field gradient along the axis. Ions are accelerated to about 200 eV at rf electric field of 60 V/cm. The computed results of the dispersion relation of the wave including cyclotron damping agree well with the experimental ones.

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The structure of a plasma-sheath transition region surrounding a negatively biased cylindrical probe in a weak axial magnetic field is systematically studied on the basis of the moment equations. A weakly ionized plasma is treated, and it is assumed that the mean free path is long but finite, and that the collision frequency is constant. Since the mean free path becomes short with decrease of the ion current collected, the collision effect plays an important role in the ion collection and the formation of the transition region between plasma and the so-called sheath. The position of the boundary between the transition region and plasma and its dependence on the magnetic field are determined by an effective mean free path. Our theory is a generalization of those of Bohm and others which includes the finiteness of the mean free path and the effect of a weak magnetic field. A reformed Bohm criterion is proposed.

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The present paper is concerned with a long time asymptotic behaviour of a weakly Landau-damped, monochromatic plasma wave in the collisionless electron plasma, the amplitude of which is assumed small but finite. The theory is based on an asymptotic expansion in terms of the decay constant of the Landau damping. The method of characteristics to integrate the Vlasov equation is brought into the scope of the asymptotic method. It is shown then that the slowly varying part of the amplitude Landau-damps if the decay time is much shorter than the period of the amplitude oscillation, whilst it oscillates if they become the same order.

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The ion cyclotron instability of a mirror-confined plasma is analyzed based on the power consumption of the internally created electrostatic field in the plasma itself. The relative importance of two kinds of ion cyclotron modes, “anisotropy” and “loss-cone”, depends on the plasma density through the instability frequency band width as well as the temperature ratio of the parallel and perpendicular components. The amount of cold ions necessary to quench these instabilities is calculated for plasmas of various densities.

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An asymptotic method for the Vlasov equation developed in a previous paper is reformulated in the Eulerian representation. Then the theory will be compared with that of Al’tshul’ and Karpman; differences between these theories will be emphasized.

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A method for measuring the space potential of a plasma by means of RF characteristics of Langmuir probe is presented. The principle of the method is based upon a behavior of the RF impedence of the plasma-sheath and -probe system. The sensitivity of the method is expected to be very high, since the RF characteristic at the space potential is much remarkable. For example, it was possible to obtain the space potential in order of 2 mV in a mercury diffusion plasma.

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An equation which governs wave motions of a thin layer of a viscous fluid falling along a vertical wall is derived on the assumptions that a thickness of the layer varies slowly and that a surface tension is essential.
When the thickness upstream is larger than that downstream, there exists a state in which the wave propagates downwards with a constant shape of the surface, while in the other cases no such a state exists. The former state is found to be stable, and in the latter the waves decay out. Numerical calculations for the initial value problem support these results.

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Solutions are obtained, using constitutive equations of anisotropy creep theory and Norton’s law, for a thick walled cylinder of an orthotropic material subjected to internal pressure. Expressions for stresses and creep rates are obtained under the assumptions (i) plane strain, (ii) generalized plane strain and (iii) plane stress. The results for plane strain case are compared with those obtained by Pai. It is shown that his conclusion that stress distribution was independent of anisotropic constants is not correct. The error appears to be due to simplified constitutive equations which has only one anisotropic constant used by him. The results indicate that creep anisotropy has a significant effect on the cylinder behaviour.

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The unsteady flow of an electrically conducting fluid, impulsively brought in motion with a constant velocity from rest at the forward stagnation point of an infinite plane wall which is an electric insulator, is considered. When a magnetic field is applied normal to the wall, its effects on the transient phenomena to the steady flow case are studied by a usual unsteady approach. The derived fundamental equation on the assumption of small magnetic Reynolds number is solved both by an expansion method into power series and by a numerical method employing the difference-differential method. Solutions obtained by series expansion method are found to be invalid for large times. On the other hand, the difference-differential method may present well behaved solutions for the transition region in the flow impulsively started from rest and those of steady flow. Numerical results are given for the velocity profile, skin friction and time required to attain a value of skin friction within 0.1% of that of steady flow case.

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The symmetrical unsteady vortices behind a circular cylinder started from rest either impulsively of with uniform acceleration were investigated experimentally using a flow visualization technique. The variation of the length of the vortices with time was determined from the photographs obtained at Reynolds numbers ranging from 31 to 1700 and dimensionless accelerations from 195 to 2.44×10⁵. The length of the unsteady vortices exceeds 4.3 cylinder diameters at about a Reynolds number of 100, or a dimensionless acceleration of 500. The secondary vortices were formed upstream side of the main vortices at Reynolds numbers higher than 550, or dimensionless accelerations higher than 5×10⁵.

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The flow of an electrically conducting and incompressible fluid at the forward stagnation point of an infinite plane wall is studied considering the effect of suction or of injection. On the assumptions of small magnetic Reynolds number and of zero electric field, it is found that the similar solution of boundary layer equations exists when a uniform magnetic field is applied normal to the wall and the velocity of suction or of injection are constant. The similar solution is expressed in a form of integral equation and obtained by iterative numerical quadratures. Numerical results for various values of parameters are given for the velocity profile, skin friction, displacement thickness and momentum thickness. Further, present numerical results for large suction or large injection are compared with those of asymptotic analysis. It can be concluded that an asymptotic analysis for large suction or large injection might be valid for K≥5 or K≤−3 and results be in good agreement with those of numerical calculations within a few percent, where K is a parameter of suction or of injection.

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Recently it was proposed that any solid possesses the melting point T_m whose dT_m⁄dP is positive in the beginning of the applied pressure, but becomes negative on further increasing pressure, resulting in a maximum T_m characteristic for the material. The new hypothesis involves another concept that a solid having a larger mass number has a relatively lower maximum T_m, whereas that having a smaller mass number has a higher maximum T_m.
It was also assumed that the metallic hydrogen is the lightest alkali metals belonging to the I-A group of the periodic table, and that the maximum melting point of the metallic hydrogen can be determined by extrapolating melting data of Cs, Rb, K, Na and Li successively. Then, There is a possibility that the Jupiter may possess a relatively cool molten metallic hydrogen core, whose temperature is definitely lower than that estimated by DeMarcus.

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