A method is hereby reported to compute briefly the maximum light intensity of the projector, with parabolic reflector or fresnel-lens and the source having nearly equal light-distribution in all dillections, and its beam is symmeti ical in relation to beam axis.
The mean light intensity in the beam angle, I_me, can be computed by means of the nomograph.(Fig.1.) And the maximum light intensity, I_ma can be obtained by multiplying I_me by K, the value of which proved to be generally approximately in this report.

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(1) The electric, radiant and heat transfer properties of the some commercial SiC heaters were investigated, and the most suitable conditions as a radiation source of infra-red ray drying were discussed in this report.
(2) Electric resistance and radiant energy of the radiators were measured in the temperature'range 15°-1000°C. According to the experimerts, the values of radiation coefficient of the radiators were 4.9-5.08×10^-12 and their emissivity calculated from them was 0.85-0.88.
As shown by theory of semi-conductor, under a crit-ical temperature T_c (°K) specific conductivity σ(Ω^-1 cm^-1) of any sample was expressed by σ=σ₀e-ε/kT
(3) Measuring the temperature difference between the surface and the central axis of the radiator by optical pyrometry, thermal conductivity K of the samples was calculated in the temperature range 700°C-1100°C. The values of K in this temperature range wefe 3-5×10^-2 cal/cm² sec deg.
(4) The convection loss of the radiators fixed horizontally was Calculated by measurement of input power and radiant energy in the state of natural and forced convection. The convection loss was well expressed by the following equations
H=FK₂ (T-T₀) 5/4 (natural convection)
H=FK₃ (T-T₀)(forced convection)
(5) To solve the practically important question to decide the relation between the suitable electric and radiant characteristics of radiator and the crystallogiaphical structure of SiC and its impurities, a more detailed research would be necessary.

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In this report are described some charcteristics of the thermal switches, mainly of the hot wire type and, for reference, of the bimetal type.
Two kinds of the action time, which are opening time (to) and reclosing time (tc) of the filaments circuit of fluorescgnt Iamps, are obtained experimentally, and indicated as following equations
t₀=A logi²/i²-i₀²
t_c=B logi²/i₀²
Where i₀ is the critical current of operation, and i is the filament current.
In our experiments are obtained the relations between t₀, or t_c and i. The results are plotted in Fig. 5. which shows how t₀ decreases and t_c increases when the current i is increases.
t₀ and t_c are plotted in Fig. 10 and Fig. 7 respectively, and two constants, A and B are obtained by calculation. As the result, we know the range of constants of the hot wire type are following A=10-12sec B=5-7sec those constants of the bimetal type are much larger.

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