This work gives an analysis of 317 inelastic interaction events. The angular and momenta distributions, etc., in the pion-nucleon centre of mass system (C.M.S.), of the secondary charged particles resulted from the collisions agree with the results of previous works and may be compared with the theoretical calculation based on the mechanism of peripheral collision.Those events in which the secondary protons are identified have been analysed as follows: (i) The total energy ω of all secondary particles except the protons in bary-centric system has been computed. The ideogram of ω distribution is given and is compared with the modified theoretical distribution calculated by Barashenkov et al. under the approximation of OPE model. At about ω= 1.5 BeV a peak has been found which is not given by the theoretical curve. Events in this peak have been preliminarily analysed. (2) By using the secondary protons of our events and those events of JINR under the same conditions, the coefficients of inelasticity, Kз, in 'mirror' system have been computed. The distribution of Kз is given and is compared with the modified theoretical distribution calculated by Barashenkov et al. under the approximation of OPE model. Moreover, the events of different values of Kз have been analysed and discussed tentatively by means of the concept of target mass and using the method of F plot proposed by Duller Walker.
This work gives an analysis of 317 inelastic interaction events. The angular and momenta distributions, etc., in the pion-nucleon centre of mass system (C.M.S.), of the secondary charged particles resulted from the collisions agree with the results of previous works and may be compared with the theoretical calculation based on the mechanism of peripheral collision.Those events in which the secondary protons are identified have been analysed as follows: (i) The total energy ω of all secondary particles except the protons in bary-centric system has been computed. The ideogram of ω distribution is given and is compared with the modified theoretical distribution calculated by Barashenkov et al. under the approximation of OPE model. At about ω= 1.5 BeV a peak has been found which is not given by the theoretical curve. Events in this peak have been preliminarily analysed. (2) By using the secondary protons of our events and those events of JINR under the same conditions, the coefficients of inelasticity, Kз, in 'mirror' system have been computed. The distribution of Kз is given and is compared with the modified theoretical distribution calculated by Barashenkov et al. under the approximation of OPE model. Moreover, the events of different values of Kз have been analysed and discussed tentatively by means of the concept of target mass and using the method of F plot proposed by Duller Walker.
Cucurbitine is a natural amino acid newly found as the effective component in the crude drug, Cucurbita moschata Duch, which inhibits the growth of immature Schisto soma japonicum. This paper describes the X-ray diffraction studies on the structure of the perchlorate of the amino acid. Preliminary examinations show that the crystal belongs to the monoclinic system with space group P21 and unit cell dimensions a = 5.68 ± 0.01?, b = 12.78 ± 0.01?, c = 6.23 ± 0.01?, β = 107°26′± 12′. The trial structure has been derived by the three-dimensional Patterson analysis and refined by the two-dimensional Fourier syntheses. The absolute configuration of the Cucurbitine molecule has been determined by the anomalous scattering effect of the chlorine atom with CuKx radiation. It is of the form: Some important features of the structure of both the molecule and the crystal are described.
Cucurbitine is a natural amino acid newly found as the effective component in the crude drug, Cucurbita moschata Duch, which inhibits the growth of immature Schisto soma japonicum. This paper describes the X-ray diffraction studies on the structure of the perchlorate of the amino acid. Preliminary examinations show that the crystal belongs to the monoclinic system with space group P21 and unit cell dimensions a = 5.68 ± 0.01?, b = 12.78 ± 0.01?, c = 6.23 ± 0.01?, β = 107°26′± 12′. The trial structure has been derived by the three-dimensional Patterson analysis and refined by the two-dimensional Fourier syntheses. The absolute configuration of the Cucurbitine molecule has been determined by the anomalous scattering effect of the chlorine atom with CuKx radiation. It is of the form: Some important features of the structure of both the molecule and the crystal are described.
It is proved that the S matrix element S(λ, k) for the z-4 repulsive potential → 1 as |λ|→∞ in the sector 0 ≤| argλ | <π/2-ε and that it has infinitely many Reggepoles in a small angle neighbourhood of the imaginary axis with their real and imaginary parts approaching ∞ simultaneously. Ordinary double dispersion relation does not hold in this case.
It is proved that the S matrix element S(λ, k) for the z-4 repulsive potential → 1 as |λ|→∞ in the sector 0 ≤| argλ | <π/2-ε and that it has infinitely many Reggepoles in a small angle neighbourhood of the imaginary axis with their real and imaginary parts approaching ∞ simultaneously. Ordinary double dispersion relation does not hold in this case.
In this paper the various properties of the rare-earth even-even nuclei (intrinsic excitation spectra, β-decay, and even-odd mass differences, etc.) are analysed with the new method presented in reference [10]. For this purpose, the single-particle levels have to be determined. It is found that on the basis of Nilsson's level scheme, with suitably chosen parameters μ and k, the spins and parities of the low-lying intrinsic spectra and the level spacing of odd-A nuclei may be explained, after taking account of the influence of pairing force. The parameters chosen are as follow: k～0.067-0.072, η～4-4.6 μ～0.59(N = 4), μ～0.45(N = 5) for proton μ～0.40-0.45(N = 5), μ～0.33(N = 6) for neutron. The variation of the energy eigenvalue induced by the change of parameter μ is estimated with the perturbation method, and the results are close to the exact eigenvalues. From the analyses of Er166, Er168, Yb170, Yb172, Yb174, Hf178, W182, Dy160 and Dy162 the following several conclusions may be drawn: 1. The majority of the low-lying intrinsic excited states of even-even nuclei may be considered as the pair-broken excited states. The calculated first pair-broken states, in spite of the large variation in their spins and parities, are observed in experiments systematically (Fig. 30). Their excitation energies range from 1.2 MeV to 1.6 MeV. The calculated variation of these energies with different nuclei agrees with experiments ap- proximately. These states correspond to the two quasi-particle excited states pointed out by Gallagher and Soloviev.2. Near the first pair-broken excited state, appears the Kπ=0+ pair excitation state. In Er166, Hf178 and W182 these pair excitation states have been observed (Fig. 32). In other nuclei, these pair excitation states have not been observed yet, because the β-decays from the neighbouring odd-odd nuclei to these states are highly forbidden or strictly forbidden. 3. The systematically occured Kπ = 2+ states (Fig. 31) in even-even nuclei (E～0.8-1.2 MeV) can not be considered as pair-broken excited states. Theoretically there does not exist in these nuclei (except Yb172) the Kπ= 2+ intrinsic state below 2 MeV. 4. The splittings in energy △E between the pair-broken doublets, K = |Ω1 ± Ω2|, vary violently with different nuclei and with different pair-broken states. △E～(40-700) KeV. 5. The variation of even-odd mass differences with different nuclei is analysed also and it is found that the even-odd mass difference depends sensitively on the single-particle level scheme. The fact that the calculated and the observed variation of even-odd mass differences agree with each other (Fig. 29) indicates that the single-particle level scheme determined in this paper is approximately correct. The average strength constant G deduced from the even-odd mass differences is close to that deduced from the energy spectra. In the calculation the cut-off energy C is chosen to be ≈ 4 MeV. (C》G). With increasing C the influences of the pairing force on the low-lying spectra may be compensated by decreasing the average strength constant G.
In this paper the various properties of the rare-earth even-even nuclei (intrinsic excitation spectra, β-decay, and even-odd mass differences, etc.) are analysed with the new method presented in reference [10]. For this purpose, the single-particle levels have to be determined. It is found that on the basis of Nilsson's level scheme, with suitably chosen parameters μ and k, the spins and parities of the low-lying intrinsic spectra and the level spacing of odd-A nuclei may be explained, after taking account of the influence of pairing force. The parameters chosen are as follow: k～0.067-0.072, η～4-4.6 μ～0.59(N = 4), μ～0.45(N = 5) for proton μ～0.40-0.45(N = 5), μ～0.33(N = 6) for neutron. The variation of the energy eigenvalue induced by the change of parameter μ is estimated with the perturbation method, and the results are close to the exact eigenvalues. From the analyses of Er166, Er168, Yb170, Yb172, Yb174, Hf178, W182, Dy160 and Dy162 the following several conclusions may be drawn: 1. The majority of the low-lying intrinsic excited states of even-even nuclei may be considered as the pair-broken excited states. The calculated first pair-broken states, in spite of the large variation in their spins and parities, are observed in experiments systematically (Fig. 30). Their excitation energies range from 1.2 MeV to 1.6 MeV. The calculated variation of these energies with different nuclei agrees with experiments ap- proximately. These states correspond to the two quasi-particle excited states pointed out by Gallagher and Soloviev.2. Near the first pair-broken excited state, appears the Kπ=0+ pair excitation state. In Er166, Hf178 and W182 these pair excitation states have been observed (Fig. 32). In other nuclei, these pair excitation states have not been observed yet, because the β-decays from the neighbouring odd-odd nuclei to these states are highly forbidden or strictly forbidden. 3. The systematically occured Kπ = 2+ states (Fig. 31) in even-even nuclei (E～0.8-1.2 MeV) can not be considered as pair-broken excited states. Theoretically there does not exist in these nuclei (except Yb172) the Kπ= 2+ intrinsic state below 2 MeV. 4. The splittings in energy △E between the pair-broken doublets, K = |Ω1 ± Ω2|, vary violently with different nuclei and with different pair-broken states. △E～(40-700) KeV. 5. The variation of even-odd mass differences with different nuclei is analysed also and it is found that the even-odd mass difference depends sensitively on the single-particle level scheme. The fact that the calculated and the observed variation of even-odd mass differences agree with each other (Fig. 29) indicates that the single-particle level scheme determined in this paper is approximately correct. The average strength constant G deduced from the even-odd mass differences is close to that deduced from the energy spectra. In the calculation the cut-off energy C is chosen to be ≈ 4 MeV. (C》G). With increasing C the influences of the pairing force on the low-lying spectra may be compensated by decreasing the average strength constant G.
The process of hydrothermal crystallization and dissolution of quartz crystals have been investigated by means of designed experiments. The possible structures of the dissolved molecules and the forms of their condensation and process of conversion before and during crystallization have been proposed. The normal and effective growth of crystals was realized by the temperature difference method.Some of the observations made on the resulting crystals are noted or tentatively explained.1. In some cases, if small crystals that fell down during their growth and reached the prism faces m {1010} of large growing crystals, parallel attachment between them was very frequently resulted, and the crystal growth was promoted at the location of contact and thus forming a stepped growth pyramid.2. Very large and widely spaced growth spirals centred on projected peaks were observed on r {1101} faces. Between the steps of very large heights there appeared some much lower but clearly visible steps, indicating the possibility of bunching of more elementary microscopic steps.3. On the faces having the highest velocities of growth such as the X {5161} faces and the {0001} basal faces the growth profiles more or less resemble liquid drops. There are parallel and sometimes interlaced markings on the 'drops' that formed on the basal faces which look not only like growth layers but also like gliding lines. The oxile direction of the inclined 'drops' are mostly parallel to the neighbouring R {1011} faces. The 'drops' on opposite {0001} faces of the crystal are directed oppositely.4. When quartz crystal was partly dissolved in hydrothermal solution stepped profile with rounded margins appeared on r-face{1101}, and layered pattern on the prism faces. They are mostly convex and some of them are concave.The results of experimental investigations are:1) The colloidal chemical behaviour of the cooled solution once used for crystal growth under hydrothermal conditions has been investigated by means of ultramicroscopy and cataphoresis and in some cases by their combination, and the flocculated aggregates have been analysed successively before and after each thermal reaction and stages of re-crystallization or phase changes up to 1050℃.The phase changes are: 2) When the once cooled solution was brought to a new hydrothermal condition of lower temperature and pressure, and subjected to cataphoresis, the total amount of flocculated aggregates collected at the anode was very much reduced, but the X-ray pattern of the sponge-like mass was nearly the same as in the previous case.The following assumptions were proposed:1) The most reasonable and representative subdivision of molecules in quartz crystals is perhaps the six-linked ring molecule occupying a volume of 2 unit cells, and owing to their body-centred close packing in a derived orthorhombic cell, a layer of such ring molecules corresponds to a step height of 1 unit cell. Eight O atoms are shared with 10 neighbouring 'true molecules'. The formula of the ring molecule in crystal should be Si6O10O8/2. The corresponding molecules in solution are hydrated six-linked ring molecules Si6O6(OH)12. 2) A group of five ring molecules in crystals, four surrounding one and all sharing one O atom with the central one, become a big derived tetrahedra molecule that occupies the height of three unit cells. Ordered or disordered ring, ribbon or sheat molecules in solution are convenient material for the crystallization of both the six-linked ring molecule or big tetrahedra molecules in crystals involving more or less 'breaking' of Si-O bonds.3) During the course of cooling of the hydrothermal solution the amount of colloidal particles in total volume should certainly be increased at the expense of the molecules in state of true solution, for the smaller molecules' polymererization may continue several steps further. On the contrary, when the hydrothermal condition is building or rebuilding up, the statistical equilibrium size of the molecular aggregates is determined at the compromise of temperature and pressure.4) When the crystal begins to dissolve, the material passing into solution is mostly segregated in domains, their further dispersion resulted in hydrated molecules of different sizes and forms. On the contrary, during crystallization the process of convertion of the molecules is mainly the loss of (OH) and sharing of O.It is reasonable to assume the existance of transitional boundary layers surrounding the crystals that are growing as well as that are subjected to solvation.
The process of hydrothermal crystallization and dissolution of quartz crystals have been investigated by means of designed experiments. The possible structures of the dissolved molecules and the forms of their condensation and process of conversion before and during crystallization have been proposed. The normal and effective growth of crystals was realized by the temperature difference method.Some of the observations made on the resulting crystals are noted or tentatively explained.1. In some cases, if small crystals that fell down during their growth and reached the prism faces m {1010} of large growing crystals, parallel attachment between them was very frequently resulted, and the crystal growth was promoted at the location of contact and thus forming a stepped growth pyramid.2. Very large and widely spaced growth spirals centred on projected peaks were observed on r {1101} faces. Between the steps of very large heights there appeared some much lower but clearly visible steps, indicating the possibility of bunching of more elementary microscopic steps.3. On the faces having the highest velocities of growth such as the X {5161} faces and the {0001} basal faces the growth profiles more or less resemble liquid drops. There are parallel and sometimes interlaced markings on the 'drops' that formed on the basal faces which look not only like growth layers but also like gliding lines. The oxile direction of the inclined 'drops' are mostly parallel to the neighbouring R {1011} faces. The 'drops' on opposite {0001} faces of the crystal are directed oppositely.4. When quartz crystal was partly dissolved in hydrothermal solution stepped profile with rounded margins appeared on r-face{1101}, and layered pattern on the prism faces. They are mostly convex and some of them are concave.The results of experimental investigations are:1) The colloidal chemical behaviour of the cooled solution once used for crystal growth under hydrothermal conditions has been investigated by means of ultramicroscopy and cataphoresis and in some cases by their combination, and the flocculated aggregates have been analysed successively before and after each thermal reaction and stages of re-crystallization or phase changes up to 1050℃.The phase changes are: 2) When the once cooled solution was brought to a new hydrothermal condition of lower temperature and pressure, and subjected to cataphoresis, the total amount of flocculated aggregates collected at the anode was very much reduced, but the X-ray pattern of the sponge-like mass was nearly the same as in the previous case.The following assumptions were proposed:1) The most reasonable and representative subdivision of molecules in quartz crystals is perhaps the six-linked ring molecule occupying a volume of 2 unit cells, and owing to their body-centred close packing in a derived orthorhombic cell, a layer of such ring molecules corresponds to a step height of 1 unit cell. Eight O atoms are shared with 10 neighbouring 'true molecules'. The formula of the ring molecule in crystal should be Si6O10O8/2. The corresponding molecules in solution are hydrated six-linked ring molecules Si6O6(OH)12. 2) A group of five ring molecules in crystals, four surrounding one and all sharing one O atom with the central one, become a big derived tetrahedra molecule that occupies the height of three unit cells. Ordered or disordered ring, ribbon or sheat molecules in solution are convenient material for the crystallization of both the six-linked ring molecule or big tetrahedra molecules in crystals involving more or less 'breaking' of Si-O bonds.3) During the course of cooling of the hydrothermal solution the amount of colloidal particles in total volume should certainly be increased at the expense of the molecules in state of true solution, for the smaller molecules' polymererization may continue several steps further. On the contrary, when the hydrothermal condition is building or rebuilding up, the statistical equilibrium size of the molecular aggregates is determined at the compromise of temperature and pressure.4) When the crystal begins to dissolve, the material passing into solution is mostly segregated in domains, their further dispersion resulted in hydrated molecules of different sizes and forms. On the contrary, during crystallization the process of convertion of the molecules is mainly the loss of (OH) and sharing of O.It is reasonable to assume the existance of transitional boundary layers surrounding the crystals that are growing as well as that are subjected to solvation.
In this article, we have introduced a new Regge trajectory, αq, with vacuum quantum numbers, αq(0) = αp(0) = 1, but α′q(0)≠ α′p(0). αq as well as αp takes part in the high energy non-exchange processes, and they interfere with each other. The consequence of the two vacuum Regge trajectories is equivalent to an effective trajectory αe, the slope of which at zero energy α′e(0) is dependent on the processes. The essential difference of our theory from the old one deduced from a single vacuum trajectory, αp, is that α′e(0) will be different for different processes. This does not conflict with the newest experiments.It is expected that the α′e(0) for K-N scattering will take different values from those of π-N and N-N. The existence of αq may not influence the relations between the total cross-sections of the crossed processes, but the polarization of the high energy nucleon after scattering will decrease much more slowly, than absence of αq, as energy increases.
In this article, we have introduced a new Regge trajectory, αq, with vacuum quantum numbers, αq(0) = αp(0) = 1, but α′q(0)≠ α′p(0). αq as well as αp takes part in the high energy non-exchange processes, and they interfere with each other. The consequence of the two vacuum Regge trajectories is equivalent to an effective trajectory αe, the slope of which at zero energy α′e(0) is dependent on the processes. The essential difference of our theory from the old one deduced from a single vacuum trajectory, αp, is that α′e(0) will be different for different processes. This does not conflict with the newest experiments.It is expected that the α′e(0) for K-N scattering will take different values from those of π-N and N-N. The existence of αq may not influence the relations between the total cross-sections of the crossed processes, but the polarization of the high energy nucleon after scattering will decrease much more slowly, than absence of αq, as energy increases.
The field distribution and electron-optical properties of electrostatically-focused image converter with plane cathode are precisely determined by means of resistance network analogue and numerical computation. The axial potential distribution is found to be expressible by the empirical formula φ = A sinh kz. Graphs are given, showing the dependence of coefficients A, k, the position of Gauss-image-plane, and linear magnification on inter-electrode spacing. An approximate formula for calculating distortion-coefficient is derived, which agrees fairly well with experimental result. Design factors are discussed.
The field distribution and electron-optical properties of electrostatically-focused image converter with plane cathode are precisely determined by means of resistance network analogue and numerical computation. The axial potential distribution is found to be expressible by the empirical formula φ = A sinh kz. Graphs are given, showing the dependence of coefficients A, k, the position of Gauss-image-plane, and linear magnification on inter-electrode spacing. An approximate formula for calculating distortion-coefficient is derived, which agrees fairly well with experimental result. Design factors are discussed.
According to the theory of the rate process of diffusion of atoms in lattice, the kinetics of long-range ordering and short-range ordering under the condition of zero long-range order in the nearest neighbour approximation has been investigated. The results obtained agree qualitatively with and quantitatively similar to the conclusions derived from the past experiments and calculations. The results obtained from the calculations of the kinetics of long-range ordering show that the process of ordering requires an induction period, the transformation curves have the form of C-curves and the degree of longe-range order depends upon time in the form of exp {-αt2} -approximately. The equilibrium values of the degree of long-range order obtained are very similar to those of the past workers. The results obtained from the calculations of the kinetics of short-range ordering in the condition of zero long-range order depends upon time in the form of exp {-βt} approximately, and the rate of ordering is so quick, that even with the fastest quenching a certain degree of short-range order exists in the specimen. The equilibrium values of the degree of short-range order also agree with the results obtained in the past.
According to the theory of the rate process of diffusion of atoms in lattice, the kinetics of long-range ordering and short-range ordering under the condition of zero long-range order in the nearest neighbour approximation has been investigated. The results obtained agree qualitatively with and quantitatively similar to the conclusions derived from the past experiments and calculations. The results obtained from the calculations of the kinetics of long-range ordering show that the process of ordering requires an induction period, the transformation curves have the form of C-curves and the degree of longe-range order depends upon time in the form of exp {-αt2} -approximately. The equilibrium values of the degree of long-range order obtained are very similar to those of the past workers. The results obtained from the calculations of the kinetics of short-range ordering in the condition of zero long-range order depends upon time in the form of exp {-βt} approximately, and the rate of ordering is so quick, that even with the fastest quenching a certain degree of short-range order exists in the specimen. The equilibrium values of the degree of short-range order also agree with the results obtained in the past.
Ausgehend von der Kohn-Nonnenmacher-Spenkeschen Ersatzschaltung werden das Schrotrauschen und thermische Rauschen in einer P-N-Fl?chendiode bei verschieden gro?em Injektionsstrom untersucht und Formeln fur deren ?quivalenten Rauschwiderstand hergeleitet.
Ausgehend von der Kohn-Nonnenmacher-Spenkeschen Ersatzschaltung werden das Schrotrauschen und thermische Rauschen in einer P-N-Fl?chendiode bei verschieden gro?em Injektionsstrom untersucht und Formeln fur deren ?quivalenten Rauschwiderstand hergeleitet.
The deviation from Cauchy's relation and the difference between the electrostaticand the optical dielectric constant for calcium fluoride are calculated respectively by usingKun Huang's method. The results of neglecting the electronic polarization in the ionic crystal are given as follows: c12-c44=0.58×1011 dyne/cm2, ε- ε0 = 3.53. The results of considering the electronic polarization in the ionic crystal are c12-c44=3.97×1011 dyne/cm2,ε - ε0 = 10.1. The experimental values are c12-c44 = 2.01 × 1011 dyne/cm2,ε - ε0 = 6.44.
The deviation from Cauchy's relation and the difference between the electrostaticand the optical dielectric constant for calcium fluoride are calculated respectively by usingKun Huang's method. The results of neglecting the electronic polarization in the ionic crystal are given as follows: c12-c44=0.58×1011 dyne/cm2, ε- ε0 = 3.53. The results of considering the electronic polarization in the ionic crystal are c12-c44=3.97×1011 dyne/cm2,ε - ε0 = 10.1. The experimental values are c12-c44 = 2.01 × 1011 dyne/cm2,ε - ε0 = 6.44.
This paper gives a generalized statement of the Bremmer theory in the case that the medium and the incident wave are of general form (it is called the local principle of the process of wave motion) and proves it schematically. The Bremmer serieses of three concrete cases are deduced in a way similar to that used by Bremmer. These are:1) Planely stratified medium, obliquely incident plane wave;2) Cylindrically stratified medium with a line source coincident with the axis of the cylinder;3) Spherically stratified medium with a point source at its centre.Finally the author has attempted to give a mathematical form for the condition that the process of wave propagation can be described rigorously by rays, and points out the unstrictness in a paper of Bellman and Kalaba.
This paper gives a generalized statement of the Bremmer theory in the case that the medium and the incident wave are of general form (it is called the local principle of the process of wave motion) and proves it schematically. The Bremmer serieses of three concrete cases are deduced in a way similar to that used by Bremmer. These are:1) Planely stratified medium, obliquely incident plane wave;2) Cylindrically stratified medium with a line source coincident with the axis of the cylinder;3) Spherically stratified medium with a point source at its centre.Finally the author has attempted to give a mathematical form for the condition that the process of wave propagation can be described rigorously by rays, and points out the unstrictness in a paper of Bellman and Kalaba.
Internal friction peaks in two types of pure silver and six types of silver alloys were investigated with a torsion pendulum of about 1 cps. Comparisons were made on the variations of internal friction of both single and polycrystalline specimens of different compositions before and after different degrees of internal oxidation.Experimental results show: (1) The peak temperature of high purity silver (99.99%) appeared at about 130℃ when internal friction was measured in air in the course of heating, but the peak disappeared when measurements were taken in a reverse course (i.e. during cooling) from a temperature of ～400℃ or above. (2) To all specimens of lower purity (99.95 % Ag) and the three types of silver alloys, two peaks, one at 130°-260℃ and another at 380-430℃, have been observed in the course of heating. The height and the position (temperature) of both peaks depend on the concentration of impurities. When measurements were taken in the course of cooling, the low temperature peak, resembling that in high purity specimens, also disappeared; but the high temperature peak remained unaffected. The effect of alloy elements seems to give rise to the high temperature peak, and simultaneously to suppress the occurence of the low temperature peak. At Al concentrations in excess of 0.05% (0.2 at. %) only the high temperature peak was observed. (3) After internal oxidation treatments the peak heights of alloy specimens decreased with increasing time of treatment.
Internal friction peaks in two types of pure silver and six types of silver alloys were investigated with a torsion pendulum of about 1 cps. Comparisons were made on the variations of internal friction of both single and polycrystalline specimens of different compositions before and after different degrees of internal oxidation.Experimental results show: (1) The peak temperature of high purity silver (99.99%) appeared at about 130℃ when internal friction was measured in air in the course of heating, but the peak disappeared when measurements were taken in a reverse course (i.e. during cooling) from a temperature of ～400℃ or above. (2) To all specimens of lower purity (99.95 % Ag) and the three types of silver alloys, two peaks, one at 130°-260℃ and another at 380-430℃, have been observed in the course of heating. The height and the position (temperature) of both peaks depend on the concentration of impurities. When measurements were taken in the course of cooling, the low temperature peak, resembling that in high purity specimens, also disappeared; but the high temperature peak remained unaffected. The effect of alloy elements seems to give rise to the high temperature peak, and simultaneously to suppress the occurence of the low temperature peak. At Al concentrations in excess of 0.05% (0.2 at. %) only the high temperature peak was observed. (3) After internal oxidation treatments the peak heights of alloy specimens decreased with increasing time of treatment.
Using etch-figure technique, we have directly observed dislocation structure of sub-boundaries in electron-beam zone-melted molybdenum single crystals. A thorough analysis of experimental results are given, these are further compared with the deductions derived from the Frank's formula for subboundaries, and the theoretical predictions are fully verified.The directions of parallel etch-lines observed on (111) plane are along the intersection lines of glide planes and climb plane, it proves that these are symmetrical tilt subboundaries composed of edge dislocations with Burgers vector 1/2. The verification of the generalized Read-Shockley formula for intersecting subboundaries revealed by etch-pitting (110) surface proves these to be asymmetrical tilt subboundaries composed of two sets of dislocations.15 sets of networks of etch-lines have been analyzed, in which 5 sets arc proved to be 1/2 / networks, 9 sets to be / networks. In the network analysis, in addition to the stereographic method used by Carrington ct al., we have developed a new method by verifying Frank's formula quantitatively and it proved to be effective in determining Burgers vectors of dislocation networks when the stereographic analysis failed to yield unique result.Besides, we have observed various patterns indicating interactions of singular dislocations with subboundaries, in particular, 'steps' on the subboundaries induced by singular dislocations and also interactions of inclusions with subboundaries. Various types of subboundary junctions and non-equilibrium subboundaries have been observed and discussed.All these results prove that the etch-figure method of observing dislocations is an effective means for the quantitative study of dislocation substructure in crystals, comparable in power with that of transmission electron microscopy.
Using etch-figure technique, we have directly observed dislocation structure of sub-boundaries in electron-beam zone-melted molybdenum single crystals. A thorough analysis of experimental results are given, these are further compared with the deductions derived from the Frank's formula for subboundaries, and the theoretical predictions are fully verified.The directions of parallel etch-lines observed on (111) plane are along the intersection lines of glide planes and climb plane, it proves that these are symmetrical tilt subboundaries composed of edge dislocations with Burgers vector 1/2. The verification of the generalized Read-Shockley formula for intersecting subboundaries revealed by etch-pitting (110) surface proves these to be asymmetrical tilt subboundaries composed of two sets of dislocations.15 sets of networks of etch-lines have been analyzed, in which 5 sets arc proved to be 1/2 / networks, 9 sets to be / networks. In the network analysis, in addition to the stereographic method used by Carrington ct al., we have developed a new method by verifying Frank's formula quantitatively and it proved to be effective in determining Burgers vectors of dislocation networks when the stereographic analysis failed to yield unique result.Besides, we have observed various patterns indicating interactions of singular dislocations with subboundaries, in particular, 'steps' on the subboundaries induced by singular dislocations and also interactions of inclusions with subboundaries. Various types of subboundary junctions and non-equilibrium subboundaries have been observed and discussed.All these results prove that the etch-figure method of observing dislocations is an effective means for the quantitative study of dislocation substructure in crystals, comparable in power with that of transmission electron microscopy.