Surface Recombination Velocity and Bulk Carrier Lifetime Measurement of Silicon Crystals by Using Photoluminescence Time Decay

The time decay for photoluminescence (PL) emitted from silicon crystals has been used to obtain both bulk carrier lifetime (Tb) and surface recombination velocity (S). Experimental results were interpreted with the assumptions that the sample was under a low-excitation condition and that the ratio of radiative to non-radiative recombination rates was constant throughout the carrier decay process. Analysis was applied to several wafers covered with different kinds of silicon dioxide (SiO2). The results indicate that PL time decay measurement is effective to obtain the values of Tb and S

A Study on the Molten Cutting of the Thermoplastic Cloth

he apparatus was made for trial, which may examine the possibility and the practicality of welding and molten cutting of thermoplastic cloth. Microstructure examination of molten parts is also done by this

Relation between Results of X-ray Testing of P. V. C Welds and Their Mechanical Strength

X-ray radiography and penetrant inspection have been applied in nondestructive testing of P. V. C welds. The relation between the image of defects and the static strength has been examined

A Study on the Stress Distribution Around Filler of Polymer Composite Materials

In this paper, process of bonding and bonding rupture of matrix and spheroid oxidizing iron grains contained in polyethylene film are photographically observed by means of optical microscope, stress distribution around filler is sought for by finite element method, and the process of rupture of bonding by stress concentration is studied

A Study on the Characteristics at Low Temperature of Welded Polycarbonate

In this study we investigated the tensile characteristics of welded polycarbonate at low temperature. This study intends to clarify the low temperature characteristics of welded part comparing with those of base material. The results of some measurements on the tensile properties from 20°C down to -70℃ are reported and the changes in tensile properties under low temperature atmosphere are discussed. Furthermore, notch and load velocity effects on the brittle fracture tendency are also discussed. Conclusions obtained in this study are summarized as follows; 1) Both welded part and base material of polycarbonate are strengthened at low temperature. 2) Welding joint efficiency of polycarbonate is very good even at low temperature. 3) Notch and load velocity effects are observed both on the base and the welded materials. 4) Correlations are observed between fracture surfaces and mechanical testing results

A Study on the Thin Plate with Carbon Fiber Reinforced Hybrid Composite

In this paper we describe an experimental study, this article is to report fundamental data of constructions attained by carbon fiber reinforced hybrid composite of O.9mm in thickness whose resin base was reinforced. As a result of this series of test and experiments, it was found that; it is possible to attain reinforced resin base of hybrid composite of C.F.R.P. 16 times as much in rigidity against bending load as compared with that of single construction was observed with composite of O.9mm lamina. It was found that sandwich construction of C.F.R.P. is superior, while, in the case of canape construction, it was found necessary to have C.F.R.P. on the tension side. G.F.R.P. has possibility to be reinforced composite material, although it is considerably less superior to C.F.R.P

Gravitational Kaluza-Klein Modes in Warped Superstring Compactification

The Kaluza-Klein (KK) modes of graviton are studied in the IIB superstring compactification where the warped geometry is realized at the Klebanov-Strassler (KS) throat. Knowledge of the metric of the KS throat enables us to determine their wave functions with good accuracy, without any further specification of the rest of Calabi-Yau space, owing to the localization of the KK modes. Mass spectrum and couplings to the four dimensional fields are computed for some type of the KK modes, and compared to those of the well-known Randall-Sundrum model. We find that the properties of the KK modes of the two models are very different in both the masses and the couplings, and thus they are distinguishable from each other experimentally.Comment: 13 pages, Table 2 replaced, the related discussion modifie

A Study on the Adhesion of the Composite Denture

In this paper we describe an experimental study, in the preceding article, authors reported about the abrasion for composite teeth, in this article are a composite denture which was newly made combining merits of the porcelain and the plastic teeth, a trial production of composite materials of the porcelain and the plastic teeth, and an experimental study of adhesion property of the composite tooth. The following summary can be made from the results of the present experiments. Adhesion of composite denture with filler of porcelain element in principal can be fully expected. In comparison with adhesion strength of P.M.M.A. to P.M.M.A., tensile joint efficiency adhered by P.M.M.A. of heat-cured type was 84-100%, while that of P.M.M.A. of low temperature cured type was 97-98%. Bending joint efficiency using the former adhesive was 87-94%, while that of the latter adhesive was 83-85%