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Volume 29, Issue 6
Displaying 1-13 of 13 articles from this issue
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Yoshio SUGE1960 Volume 29 Issue 6 Pages 359-362
Published: June 10, 1960
Released on J-STAGE: February 09, 2009
JOURNAL FREE ACCESSDownload PDF (361K) -
Part 5: Thermoelectric MaterialsMasaharu AOKI, Yoshio SUGE1960 Volume 29 Issue 6 Pages 363-370
Published: June 10, 1960
Released on J-STAGE: February 09, 2009
JOURNAL FREE ACCESSFor the purpose of obtaining superior thermoelectric materials, purification of Bi, Te and Bi2Te3 has been carried out.
Bismuth is purified by the method of alkali-treatment and zone melting in removing Cu, Ag and Pb.
For the purification of tellurium, vacuum distillation is very efficient to remove Cu, Ag and Pb.
Measured thermoelectric power a and resistivity of purified Bi2Te3 were α=235μV•deg-1, and p=1.16×10-3Ω•cm respectively.
The influence of addictive impurities on Bi2Te3 is examined. Tl, Li, Pb and Cd etc. are p-type and Cu, Ag, Se, Te, halogen and metal-halides etc. are n-type impurities.
The thermoelectric properties of PbTe, Sb2Te3, Bi2Te3-Sb2Te3 and Bi2Te3-Bi2Se3 solid solution are examined. The result shows that the solid solution of isomorphous compounds is suitable for the thermoelectric material.
By the use of (Bi-Sb)2Te3 p-type element and Bi2(Te-Se)3 n-type element thermojunctions, the temperature drop of 71.3 deg was attained with a temperature of hot junction of 30°C.View full abstractDownload PDF (2016K) -
Part 6: Absolute Measurement of Heat Absorbing PowerMasaharu AOKI1960 Volume 29 Issue 6 Pages 371-373
Published: June 10, 1960
Released on J-STAGE: February 09, 2009
JOURNAL FREE ACCESSThe heat absorbing power at the cold junction is measured in vacuum under various heat loads. The value of the coefficient of performance predicted by the theory is found to agree fairly well with the experimental result showing that, for designing practical thermoelectric cooling, theoretical calculation on heat absorption can be relied upon.View full abstractDownload PDF (809K) -
Part 7: Temperature Control of Photo-Developing VatSotaro ARAI, Norinaga SAITO, Yuko MORI, Masaharu AOKI, Yoshio SUGE1960 Volume 29 Issue 6 Pages 374-375
Published: June 10, 1960
Released on J-STAGE: February 09, 2009
JOURNAL FREE ACCESSFor controlling the temperature of photo-developer, vat with the thermoelectric panal has been devised. Cooling experiment has been carried out with a vat of 2000 cc at a room temperature of 28°C. The vat temperature dropped from 20°C to 7°C in 2 hours with 180 watt input to the panel.View full abstractDownload PDF (654K) -
Akira OTA, Tomoyasu NAKANO, Masaharu AOKI, Yoshio SUGE1960 Volume 29 Issue 6 Pages 375-377
Published: June 10, 1960
Released on J-STAGE: February 09, 2009
JOURNAL FREE ACCESSThermoelectric cooling is applied to prevent overheating of power transistor in operation.
Thermal resistance θ of transistor is determined by the shape of the cooling device; it does not vary with the power input for cooling.
The thermoelectric cooling is commendable (1) when the transistor has to be placed in a limited space, (2) when the transistor noise is to be lowered.View full abstractDownload PDF (235K) -
Kin-ichi UEMURA1960 Volume 29 Issue 6 Pages 377-383
Published: June 10, 1960
Released on J-STAGE: February 09, 2009
JOURNAL FREE ACCESSThermoelectric cooler may be designed from two different points of view: to obtain maximum temperature drop and to obtain optimum coefficient of performance
. Cooling by cascades of two and three stages for practical use has been devised with p and n types of Bi2Te3 for obtaining deep temperature drop. Experimental results are given in regard to maximum temperature drop and useful cooling at various cascade ratios.
The temperature drop at the cascade ratio (the ratio of the number of elements in upper stage to that in lower stage) of about 1:20 is large; it falls rapidly as the number of elements in lower stage is reduced.
The absorbed heat increases linearly with the decrease in temperature difference at the same rate as in the case of single stage cooling.
The temperature difference depends upon the hot junction temperature. Hence, four or more stage cooling is but vain elaboration.View full abstractDownload PDF (1159K) -
Kin-ichi UEMURA, Yuzo OMURO, Yoshiyuki MATSUHASHI1960 Volume 29 Issue 6 Pages 383-388
Published: June 10, 1960
Released on J-STAGE: February 09, 2009
JOURNAL FREE ACCESSA thermally insulated 25 litre chamber is cooled by thermoelectric system consisting of 42 couples connected in series and mounted in two rows on rear and two side walls. The figure of merit of the present thermoelement is Z=1.81×10-3 deg-1.
The heat evolved at the hot junctions is dissipated by natural convection. For obtaining good heat exchange at the junctions, the rediators, made of copper, are soldered directly to the hot and cold sides of the elements.
A long cylindrical leg of copper is inserted between the cold fin and the cold side of the element, thus making the thermal insulating wall much thicker.
The results of the test was as follows; with D, C power consumption of 60 watts a temperature drop of 30 deg was obtained, and with a power of 120 watts the temperature drop was 33.6 deg from the ambient temperature of 30°C. Steady conditions was set up in 4 hours.View full abstractDownload PDF (1839K) -
Kin-ichi UEMURA1960 Volume 29 Issue 6 Pages 389-395
Published: June 10, 1960
Released on J-STAGE: February 09, 2009
JOURNAL FREE ACCESSThis paper deals with the analogy between the cooling by thermoelectric system and that by compression system, theoretical consideration about the thermoelectric refrigeration in general, construction of an experimental refrigerator, observed value of the cooling capacity and its theoretical treatment.
The experimental refrigerator is of 35 l capacity with polystylene sheet inside lining and foamed polystylene wall insulation. The cooling system, placed in the rear of the compartment, consists of two single-stage thermoelectric panels, each with 42 couples in series assembled and set in polyester resin. Aluminium heat absorber and water-cooled heat dissipator are electrically insulated from but thermally conductive to cold and hot sides of the panels to obtain good heat transfer. With the compartment empty and the ambient temperature at 30°C, 34 degree drop of interior air tem-perature in three hours of operation was recorded. Observed cooling effect, which involves the heat absorbed by the system and the heat leakage through walls at steady state, was in good agreement with the calculated pumping effect of the system.View full abstractDownload PDF (1112K) -
Yuzo OMURO1960 Volume 29 Issue 6 Pages 395-400
Published: June 10, 1960
Released on J-STAGE: February 09, 2009
JOURNAL FREE ACCESSSome experiments on the performance of a thermobattery using Bi2Te3 as the thermoelectric material are carried out. The thermobattery used is composed of 40 thermocouples, mounted in a heat-storing box covered with glass plates. The figure of merit Z of the material was 2.29×10-3°K-1 at room temperature, and the highest thermocouple efficiency realized in the experiments was 1.76% under the temperature difference of 49.5°C. The efficiency of heat absorption depended on the nature of the surface, the area and the temperature of the heat collector and the condition of shielding. It ranged from 36% to 39% in the experiments, hence the highest over-all efficiency obtained experimentally was 0.69%.
We may perhaps obtain the material having the mean Z value of 3.5×10-3°K-1 over the tem-perature range considered, and by assuming the heat absorption efficiency of 70%, which is practically possible, it is promissing that about 3% of the incident solar energy will be converted to electricity under the temperature difference of about 80°C. This implies the practicability of Bi2Te3 thermo-batteries to some extent.View full abstractDownload PDF (433K) -
Iwao TERAMOTO, Shigetoshi TAKAYANAGI1960 Volume 29 Issue 6 Pages 400-404
Published: June 10, 1960
Released on J-STAGE: February 09, 2009
JOURNAL FREE ACCESSThe electrical properties of Bi2-xSbxTe3-ySey with stoichiometric composition of metal components (Bi and Sb) and metalloid components (Te and Se) are investigated. These materials are prepared by melting, quenching and annealing. It is found that the crossover points of the thermoelectric power from p-type to n-type coincide with the electrical conductivity minima, and value of y corresponding to these intrinsic characteristics increases with increasing x. X-ray observations disclosed a continuous solid solution with rhombohedral structure except in the region where the composition is close to Sb2Se3.
In the latter region, curves of electrical conductivity and thermoelectric power show discontinuities and admixture phases of rhombohedral and orthorhombic structures appear. Based on a model of chemical bonding in compounds of the type of A2VB3VI, explanation is given to the observed results.View full abstractDownload PDF (459K) -
Ryozo FUJIMOTO1960 Volume 29 Issue 6 Pages 405-411
Published: June 10, 1960
Released on J-STAGE: February 09, 2009
JOURNAL FREE ACCESSThe electric spark machining has recently been put to practical use in precision machining and has been developed rapidly. This paper deals with one of the causes that give rise to the difference in electric erosion by reversing the polarity of the spark.
Observation is made on the ratio of anodic to cathodic erosion of various metals. By crater measurement, single discharge between metals of the same kind is found to cause erosion more on the cathode than on the anode. By successive discharges in spark machining, however, the erosion is more on the anode. This is explained as due to a layer of electrified metal chips being formed on the cathode which is confirmed experimentally.View full abstractDownload PDF (3800K) -
Hitoshi SAKAMOTO, Shoji TANAKA1960 Volume 29 Issue 6 Pages 412-420
Published: June 10, 1960
Released on J-STAGE: February 09, 2009
JOURNAL FREE ACCESSThin luminescent films of several useful phosphors are formed upon adequate substrates in two steps: vacuum evaporation followed by post firing in suitable atmospheres. Among the phosphors, ZnS:Cu:Cl powder samples of various Cu concentrations are prepared and the relation of the relative intensity of their blue and green emissions to the Cu concentration is examined. The luminescence properties are investigated by the excitation with highly accelerated electron beam. From the experimental results about emission spectra, decay curves, and dependences of, the luminescence intensity upon beam current density and accelerating voltage, the following are presumed.
The luminescence centers of the films are the same as those of their parent powder phosphors, and by the post firing, nearly amorphous states and non-uniform constitution of the evaporatedd films are recovered to nearly the same crystalline states and uniform constitution, as of the powder phosphors.
The penetration range of electron beam through phosphors can be determined from the: linear-dependency of luminescence intensity of the films uopn the accelerating voltage, The- following, formulas are obtained as the relation between the penetration range through solids and the energy-of electron beam, i.e., R=1.6×10-6×V1.6 for CaWO4 and R=2.0×10-6×V1.6 for ZnS. (R and V are in cm and in kV, respectively) Their results, which might have been influenced by secondary products such as secondary electron, are compared with the outcome of Thpmson-Whiddingtons law.View full abstractDownload PDF (762K) -
Masao NAKAJIMA, Mamoru IKEGAME1960 Volume 29 Issue 6 Pages 420-426
Published: June 10, 1960
Released on J-STAGE: February 09, 2009
JOURNAL FREE ACCESSThe growth process of germanium single crystals from melt by Czochralski method is studied under various conditions.
As to the external shape of the crystal, if the rate of growth perpendicular to the pulling-up direction is fairly fast, it is regular hexagonal, square and hexagonal when grown in ‹111›, ‹100› and ‹110› directions respectively, but if the rate is slow, it is circular regardless of the direction of growth.
Supercooling of the melt and anisotropy of radial growth rate influence the shape of the crystal at early stage of the growth, the anisotropy seemingly depending on the degree of supercooling.
Ratios between growth rates of the main faces in highly supercooled state of the melt have been determined as
V{111}‹111›: V{110}‹110›: V{100}‹100›=1/√:1/√2:1
The crystal grows with the plane of highest atomic packing, the {111} plane, as its front in accord with Bravis' rule. The observed crystal surface perpendicular to the pulling-up direction, therefore, is bounded by {111} planes belonging to various systems and should have a certain characteristic appearance, for instance hexagon or square.View full abstractDownload PDF (3664K)
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