MEASUREMENTS OF THE pH DEPENDENCE OF LOW FREOUENCY SOUND ABSORPTION IN SEA WATER

The dependence of sound absorption coefficient in natural sea water on pH at frequencies of 2.91,6.82and 10.76 kHz has been measured by the resonator method.Measure-ments were made at 12.6℃ in the pHrange 6.48—8.51.Comparison of the experimental results with predictions based on various equations isgiven.One of the principal objectives in this paper is to examine the contribution of the MgSO_4 absorption insea water by reducing pH to low enough values where the pH-dependent absorption losses become negligible.It seems clear that in order to predict sound absorption in sea water more accurately at both low and highfrequency ranges with an united equation,the equation should include the MgHCO_3~+ absorption term as wellas the MgCO_3 term.     

PROPENSITY RULES IN Ar—IMPACT EXCITATION OF H^— IN DOUBLY EXCITED STATES

We have theoretically investigated excitation processes of H^- ions in the doubly excited states by Ar-impact,using the impulse approximation and employing the hyperspherical wavefunctions.We have found that the H^- ion in the double excited states tends to conserve its initial states as a “floppy linear triatomic molecule” during excitation processes except for the restriction arising from the Pauli exclusion principle for two atomic electrons.     

TEMPERATURE DEPENDENCE OF THE SOUND ABSORPTION IN SEA WATER DUE TO MAGNESIUM SULFATE

In this paper,the expressions for the relaxation frequency and the maximum absorption perwavelength of the MgSO_4 relaxation as a function of temperature are presented,based on the datafor sound absorption in natural sea water measured by the reverberation method at 27 different tem-peratures between 4 and 29℃.     

ON THE PROBLEM OF THE DUAL CHARGE (MAGNETIC MONOPOLE) OF NON-ABELLAN GROUPS (Ⅱ)

The method of relating the gauge potential to the connection on a spherical surface developed in a previous paper is generalized to the discussion of the potential of an SU(2) magnetic monopole with O(5) symmetry. Expressions for the potential of the monopole with double string singularity or single string singularity are obtained. Finally, by a combined coordinate-gauge transformation, we obtain a string free expression for an SU(2) magnetic monopole with O(5) symmetry.     

THE AVERAGE FIELD OF THE ISOBAR △(1232) IN NUCLEI

The one boson exchange nuclear force is applied to the discussion of the nucleon-△ interaction. The coupling constant is determined by the straton model. Assuming that the wave function is unaltered by the presence of △, we are able to obtain the average field of the isobar in the nuclei approximately. The qualitative feature obtained is that the average field of △ is shallower then that of nueleon by an amount of～15 MeV.     

WHAT IS THE NATURE OF THE NEWLY DISCOVERED HEAVY PARTICLE γ(9.5)

In this paper, we discuss the nature of the newly discovered heavy particle Y（9.5）. Five possibilities of experimental criteria are analysed. We show that if Y is a heavy photon, an intermediate boson, a bound state of straton-antistraton or a hadron without valence stratons, and all the Γee will differ by several orders of magnitude and can therefore be discriminated easily in e⁺ e^-collision experiments. The width value Fee and its ratio of γ to γ' are not identical for the case of colour excited states of meson and the case of bound states of the new straton-antistraton. The masses of other existing new particles can also be predicted. In particular, the masses of weakly decaying heavy particles are not the same for these two cases, which may be regarded as a criterion to discriminate between these two cases. We have also discussed the main decaying properties of γ for these five possibilities.     

~(13)C CP/MAS OF MOTIONS IN SOLID POLYMERS

High-resolution 13C spectra of solid polymers are often acquired with cross polarization with magic angle spinning (CP/MAS) to take advantage of the abunda ntly available protons in the polymer chains. The sequence for transferring mag netization from 1H to13C using Hartmann-Hahn spin locking in the rotating frame is now a standard in commercial solidstate NMR spectrometers.     

A RELATIVISTIC EQUATION OF MOTION FOR MANY-BODY SYSTEM(Ⅱ)

A relativistic equation of motion for many-body system is established. The relativistic potential is a certain rearrangement of the irreducible series of many-body B-S equation. Considering the two-body irreducible B-S kernels only the many-body potential is expressed as a sum of two-body ones.     

SINGLET DEUTERON INTERMEDIATE STATE IN d-d FOUR-BODY BREAKUP REACTION (Ⅱ)

At C.M. angles 90°and 64°two-dimensional spectra of protons emitted from singlet deuterons were measured under such geometry where the kinematic ambiguty was small. From the data it is obtained that the breakup energy E_B of the singlet deuteron state is (52+21)keV.     

STUDY ON BINDING PROBLEM OF Δ(1232) IN NUCLEI WITH HARTREE-FOCK METHOD

The binding problem of isobar Δ(1232) in ⁴He ¹²C and ¹⁶O systems is studied in detail by Hartree-Fock method. The OBEP is used for the nucleon-nucleon potential and the nucleon-Δ(1232) interaction. The calculated results show that Δ(1232) can be bound only in ⁴He and not in ¹²C and ¹⁶O systems.     

ATOMIC CHARGE SUPERPOSITION CALCULATIONS OF STM IMAGES OF 2D-ORDERED AMINO ACID ADSORBATES(Ⅱ)

In the preceding paper, we have successfully used the atomic charge superposition (ACS) method to calculate STM images of 2D-ordered structures of glycine molecules adsorbed on graphite (HOPG). In this work we focus on alanine/HOPG system. Firstly, we make a thorough searching for all of the possible 2D-ordered aggregation structures that can form linear chains or 2D nets of hydrogen bonds between the molecules and simultaneously satisfy the Van der Waal's radii of the condtituent atoms, just like in the case of 3D crystal of the molecules. Secondly, in order to interpret the experimental images, we use the ACS method to calculate STM images of the possible structures. It turns out that many of the experimental images can be interpreted satisfactorily with their calculated counterparts. This result further exhibits the great potential of using STM to study organic and biological molecules.     

THEORY OF SOLITON GENERATION AND LATTICE RELAXATION IN POLYACETYLENE (Ⅰ) GENERAL FORMALISM

This series of papers is devoted to the theory of soliton and polaron generation in polyacetylene by both radiative and non-radiative processes. In the first paper of this series a general formalism is presented which combines the Lattice relaxation approach for the multiphonon process developed by Huang and many others with the consistency condition in terms of the Bogoliubov-de Gennes equation and the gap equation. The exact adiabatic electron wave functions consistent with the different lattice syimnetry breaking in the initial and final states are used to calculate the transition probability between these multi-electron states. The formalism presented is illustrated by deriving a general expression for the non-radiative decay rate using the steepest descent method in the case of stronc coupling. The theory developed here canbe applied to treating the quantum. transitions between states of differnet symmetry breaking when the multi-electron background effect and the consistency condition are essential.The applications of the general formalism to polyacettyene and the comparison with numerical results and the recent experiments tvi11 be given in the succeeding papers.     

SEEKING FOR THE U(5) LIMITING CASE OF IBA-Ⅱ

In the region of even-even nuclei from A=96 to A=120, only the energy spectrum of ¹¹⁰₄₈Cd₆₂ may be described by IBA-Ⅱ involving the states {N_π +N _L -1,1}. But it can be described by IBA-Ⅰ too. To distinguish these two schemes, more angular momentum measurement is needed.     

MEASUREMENTS OF ACOUSTIC ABSORPTION ATTENUATION FOR FREQUENCY RANGE OF 0.2-2 kHz IN SANDY SEDIMENTS OF YELLOW RIVER(HUANGHE)

The measurements of the sound attenuation in sandy sediment of Yellow River(Huanghe)have been made in situ by explosive sources.The attenuation coefficients are determined for thefreqency range of 0.2-2kHz.The experimental results show that the attenuation coefficient α(dB/m)increases approximately as the square of frequency for the frequency range of 0.2-2kHz.Theexperimental results is in agreement with the theoretical results.In addition the sound velocity,density,porosity and grain size distribution of the sediment are given in this paper.     

QUARK MASS RENORMALIZATION IN LATTICE GAUGE THEORY (Ⅱ) BARYON MASS CALCULATION

Using the renormalized quark mass m(g) obtained by fixing the ρ meson mass, we calculate the masses of the baryon states as a function of 1/g² in lattice gauge theory with fermions by variational method. The results are in agreement with experimental values in the range of 1/g² between 0.1 to 0.9.     

TURNING-POINT CONVERGENCE-ZONES IN UNDERWATER SOUND CHANNELS(Ⅱ)A GENERALIZED RAY THEORY

A generalized ray solution,which can be used for calculating the acoustic fields near the causticsand turning points,is obtained by using a generalized phase-integral approximation.This solutionhas a clear physical picture and is convenient for the numerical calculation.The caustic structure andthe intensity distribution at the turning-point convergence-zones in underwater sound channels arediscussed in detail,and the simple and widely applicable intensity expressions are given.The theo-retical analysis shows that for high-pass signals and narrow-band signals,the signals received at theturning-point convergence-zones have the same waveform as the emitted signal or its Hilbert transform.     

THE EFFECT OF SUBSTITUTION Fe FOR Cu IN La_(1.85)Sr_(0.15)CuO_(4-δ) POLYCRYSTALLINE SAMPLES

The resistivity, hall coefficient, DC susceptiblity and differential specific heats of La1.85Sr0.15Cu1-xFexO4-δpolycrystalline samples were measured. The superconducting transition temperature Tc, the superconducting volume fraction, the carrier concentration and the magnitude of the specific heat anomalies become lower and smaller rapidly with increasing Fe doping content. The metal behaviour at normal state is changed into semi-conductor behaviour by Fe doping. The experiment results indicate that perfectness of Cu-O plane in LaSrCuO system is significant for forming optimal superconducting phase and the magnetic ions act as pair breakers. The Fe ion doping at Cu site reduces greatly the electron density of states at Fermi level.     

A STUDY ON THE ULTRASONIC VELOCITY AND ATTENU-ATION IN NdFeB MAGNET WITHIN THE TEMPERATURE RANGE OF 80 - 300K (Ⅱ)

Based on the ultrasonic measurements of an isotropic NdFeB magnet in the temperature range of 77 - 300 K, it was found that the elastic parameters, such as Young's modulus E, and Poisson ratio v, change abruptly near the spin reorientation temperature Tsr. This indicates that soft mode emerges in the process of spin reorientation. Thermal hysteresis was observed during heating-up and cooling-down processes. Both Debye temperature and heat capacity were calculated, which suggests that the magnetic entropy of the Nd-sublattice is larger in easy-cone state than in easy-axis state.