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Vol. 7, No. 6 (1950)

1950-03-20
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CONTENT
PHASE COMPENSATION IN POWER OSCILLATORS
PING-CHUAN FENG, PENG-FEI HSU
1950, 15 (6): 59-71. doi: 10.7498/aps.7.59
Abstract +
Conditions for correct phase angle are examined for several types of power oscillators. Several phase compensating circuits are discussed. Experimental results show reasonable agreement with theoretical analysis.
ON THE BINDING ENERGIES OF THE NUCLEI 6Li AND 7Li——PART II NUMERICAL CALCULATION FOR 6Li (Contributions from Institute of Modern Physics, Academia Sinica, No. 4)
YEH LUNG-FEY
1950, 15 (6): 62-82. doi: 10.7498/aps.7.62
Abstract +
By using the formulae obtained in Part I for the calculation of the binding energy of 6Li, a numerical estimate is made here-the variational function being chosen rather roughly. The results are in favour of the two-range nuclear potential considered previously, and indeed indicate a larger ratio of the two ranges, the ratio being not smaller than three.
STUDY OF FREQUENCY STABILITY OF ELECTRON- COUPLED OSCILLATORS
PENG-FEI HSU, PING-CHUAN FENG
1950, 15 (6): 72-80. doi: 10.7498/aps.7.72
Abstract +
This paper points out that: (1) an electron-coupled oscillator has a sluggish loop characteristic with respect to supply voltage, (2) the most commonly used electron-coupled oscillator circuit is an incomplete electron-coupling circuit and has rather poor frequency characteristics, (3) the frequency stability can be greatly improved by applying phase compensation, (4) the best e.c.o. circuit is a modified Colpitts oscillator with grounded cathode.
DIFFUSE BANDS IN ABSORPTION AROUND THE SODIUM PRINCIPAL DOUBLETS IN THE PRESENCE OF NITROGEN AND HYDROGEN
T. S. KE
1950, 15 (6): 81-95. doi: 10.7498/aps.7.81
Abstract +
Following the observation of the diffuse absorption bands near the second member of the principal series of Rb and Cs by Ny and Chen in the presence of foreign gases, we were led to study the absorption spectrum of sodium in the presence of nitrogen and hydrogen with a Hilger E-316 quartz spectrograph and a 10-foot grating spectrograph of Eagle mounting. Corrosion resistant MgO windows were used in the absorption tube so that both the absorbing and the perturbing atoms within the absorbing column had a homogeneous concentration. Diffuse absorption band was observed only by the shorter wave-length side of the third member of the principal series but not by any of the others. The separation between the intensity maximum of the diffuse band and the principal lines is larger in the case of hydrogen than that of nitrogen. They are 3.48 A for nitrogen and 4.17 A for hydrogen. The wavelength of the intensity maximum of these bands are respectively 2849.4 A and 2848.7 A for nitrogen and hydrogen.
OF THE BINDING ENERGIES OF THE NUCLEI 6Li AND 7Li——PART Ⅲ. NUMERICAL CALCULATION FOR 7Li (Contributions from Institute of Modern Physics, Academia Sinica, No. 5)
KING SING-NAN
1950, 15 (6): 83-96. doi: 10.7498/aps.7.83
Abstract +
By using the formulae obtained in Part I for the calculation of the binding energy of 7Li a numerical estimate of the binding energy of 7Li is made in accordance with the variational method, the wave function being chosen rather roughly. The results here are also in favour of the two range potential considered previously by Peng and Chang, and in particular the results indicate that the ratio of the two ranges of the nuclear potential may be not less than 3, as in the case for 6Li treated above, Part II.
INTERNAL FRICTION AND GRAIN BOUNDARY PRECIPITATION DURING THE AGING OF AN AL-CU ALLOY
T. S. KE
1950, 15 (6): 96-101. doi: 10.7498/aps.7.96
Abstract +
The precipitation at the grain boundaries during aging at 200℃ of an Al-4% Cu alloy was studied by measurements of the internal friction associated with the viscous behavior of grain boundaries. This internal friction was measured also at 200℃ with a torsion pendulum having a frequency of about one cycle per second. The results showed that the internal friction first decreases with aging but starts to rise after an aging of 6 1/2 hours. At very long aging times, the internal friction decreases again as the aging proceeds. Such a change of internal friction indicates a corresponding change in the nature of the "precipitates" at the grain boundaries during aging. This is in conformity with the results of metallographic examinations. A preliminary understanding toward the nature of these "precipitates" was obtained on comparing the results of internal friction measurements with those of metallographic examination.
ON THE ADVANCED SOLUTION OF THE WAVE EQUATION
HSIN P. SOH
1950, 15 (6): 97-104. doi: 10.7498/aps.7.97
Abstract +
It is shown that the advanced solutions of the wave equation are identical with the retarded solutions when the boundary integrals are properly taken care of.
ON THE BINDING ENERGIES OF THE NUCLEI 6Li AND 7Li——PART I. GENERAL FORMULATION (Contributions from Institute of Modern Physics, Academia Sinica, No. 3)
KING SING-NAN
1950, 15 (6): 102-111. doi: 10.7498/aps.7.102
Abstract +
By using the nuclear potential obtained by Peng and Chang as a working hypothesis, we have obtained the general formulae for computing the binding energies of 6Li and 7Li, the wave functions being approximated by those of a definite shell formation of the nucleons.