The balls sintered in 1510℃ have the best combination properties,with a density of 18.17 g/cm3,balls diameter variable of 0.12mm,crushing pressure of 54kN,compression rate of 30.6%.

The results of XRD showed that the components of balls werea- quartz, cristobalite, Fe_2O_3, Ca_2Al_2SiO_7, NaAlSi_3O_8, CaAl_2Si_2O_8, KAlSi_3O_8 and 3Al_2O_3·2SiO_2, etc.

Activity attracted farmers were balls (21.40%), body building (14.30%), chess (11.71%), sport news (10.58%), sport traveling (10.20%) and playing dragon and lion dance (9.60%) in order.

Balls and quasi-metrics: A space of homogeneous type modeling the real analysis related to the Monge-Ampère equation

Since all of these convergence balls have the same center x*, they can be viewed as a homocentric ball.

The exchausted hot air is directly used to dry bearing balls.

An example demonstrates that the balls of initial states for which the latter property follows from the results are large enough to be used in actual computations.

No contamination of the mixture by the material of the balls and vessel during mechanical treatment was detected.

The isothermal transformation of austenite in a ball-bearing steel within thetemperature range between martensite point M and room temperature has been investigated by electrical resistance measurements.The steel employed was ofcommercial production containing 1.43% Cr and 1.02% C and its martensite pointis 159℃ when quenched from 1100℃.The specimen was first quenched toroom temperature(in which state it contained 17% retained austenite),and thenupquenched to isothermal bath in which its transformation...

The isothermal transformation of austenite in a ball-bearing steel within thetemperature range between martensite point M and room temperature has been investigated by electrical resistance measurements.The steel employed was ofcommercial production containing 1.43% Cr and 1.02% C and its martensite pointis 159℃ when quenched from 1100℃.The specimen was first quenched toroom temperature(in which state it contained 17% retained austenite),and thenupquenched to isothermal bath in which its transformation was followed.Theeffect of tempering of martensite was eliminated by employing two specimens ofdifferent martensite contents.1)By comparing the kinetics of isothermal transformation below and abovemartensite point,it was concluded that isothermal transformation below M pointtakes place by the martensite process and not by intermediate transformation(bainitic),in.spite of the presence of large amount of martensite and relativelyhigh temperature at which the transformation takes place.2)From kinetics considerations it appears that isothermal transformationof retained austenite to martensite takes place not by the formation of new nuc-lei but mainly by the growth of already existing martensite.This would alsoinfer that coherency between martensite and austenite is not destroyed(or notcompletely destroyed)during quenching transformation.3)The tempering of martensite appears to be the controlling process forthe isothermal transformation of retained austenite to martensite,such that theelastic strain energy relaxed by tempering of martensite exceeds the difference offree energies between the two phases.The activation energy of tempering ofmartensite within the temperature range considered(below 150℃)was found tobe 13,300 cal/mol,which compares favourably well with the value of 16,000 cal/molas given by Averbach and Cohen in 1953.4)The results show that isothermal keeping for prolonged duration at theneighbourhood of 100℃ brings about maximum amount of transformation of re-tained austenite.That is,at either higher or lower temperatures and for a speci-fied time,the amount of austenite-martensite transformation is less.This is signifi-cant for practical heat-treating of precision gauges and tools for which dimen-sional stability is important and high temperature tempering may not be de-sirable for hardness consideration.

The changes in the spontaneous electrical activity and in various kinds of evoked potentials of the cerebral cortex of the rabbit were studied during the period of post-natal development. Continuous spontaneous electrical potential changes of the cerebral cortex are first detectable about one week after birth. They attain the adult pattern about the end of the third week. Local application of 2% strychnine sulphate solution can already generate "strychnine spikes" during the first few days after birth, though...

The changes in the spontaneous electrical activity and in various kinds of evoked potentials of the cerebral cortex of the rabbit were studied during the period of post-natal development. Continuous spontaneous electrical potential changes of the cerebral cortex are first detectable about one week after birth. They attain the adult pattern about the end of the third week. Local application of 2% strychnine sulphate solution can already generate "strychnine spikes" during the first few days after birth, though there is much longer lag in their onset than in adult animal. The spikes are also of smaller voltage, slower time course and lower frequency. Among the evoked potentials, the response due to direct electrical stimulation of the cortex is the first to become elicitable, in a number of rabbits on the very first day after birth. The response of one hemisphere due to the stimulation of corresponding points of the other hemisphere and also the cortical response to antidromic stimulation of the pyramidal tract usually become obtainable a little later, but all within the first week. One or two days before the opening of the eyes which occurs about twelve days after birth, visual stimulation can already evoke typical responses in the visual cortex. A number of baby rabbits were ,born and continuously kept in the dark room while a number of others had their eye balls destroyed shortly after birth: by these means the effect of lack of light stimulation on the maturation of the electrical activity of the visual cortex was tested. The result was negative. The author is indebted to Prof. T. P. Feng for guidance throughout this work.

A second-approximation solution for the pressure distribution between two elastic bodies in contact is presented. In addition to the terms used by Hertz as the description of a general surface of contact, the present theory will contain the next higher-order terms of its Taylor's series expansion, such that the coefficients of the Hertz second power terms as well as the dominant fourth-power term is satisfied. Hence, the second order effect is a correction to Hertz theory which increases both with the increase...

A second-approximation solution for the pressure distribution between two elastic bodies in contact is presented. In addition to the terms used by Hertz as the description of a general surface of contact, the present theory will contain the next higher-order terms of its Taylor's series expansion, such that the coefficients of the Hertz second power terms as well as the dominant fourth-power term is satisfied. Hence, the second order effect is a correction to Hertz theory which increases both with the increase of normal load and with the increase of eccentricity of the contact. ellipse. method of change of variables is adopted in the process of integration. The solution, thus obtained, agrees exactly with that obtained by Cattaneo when reduced to his special case of two solids of revolution in contact.To illustrate the usefulness of the present theory, the problem of contact between a ball and the outer race of a ball bearing is studied. Curves are plotted to show that the relative magnitude of the second order effect varies with the shape ratio of the contact ellipse at various normal loads.