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Volume 111, Issue 12
Displaying 1-6 of 6 articles from this issue
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Masamitsu Masutani1991 Volume 111 Issue 12 Pages 619-624
Published: December 20, 1991
Released on J-STAGE: December 19, 2008
JOURNAL FREE ACCESSInfrared optical characteristics such as homogeneity, MTF and veiling glare of single and polycrystalline germanium are compared to reveal the optical difference of single and polycrystalline. MTF and veiling glare of both types show no significant difference for the practical use. The transmittance of small area of polycrystalline germanium plate varies 4 to 5% and the average transmittance is 1.7 to 2.2% less than that of single cristalline. The important factor of selecting germanium for an optical system is transmittance and homogeneity.View full abstractDownload PDF (782K) -
Hironori Hirata1991 Volume 111 Issue 12 Pages 625-630
Published: December 20, 1991
Released on J-STAGE: December 19, 2008
JOURNAL FREE ACCESSWe newly define information which evaluates the structure of ecological flow-networks. Using an analogy of itineraries of moving media to sequences of symbols, we evaluate the divergence from equiprobability and that from independence using the concept of entropy. The proposed information index shows the degree of organization of networks. We show that each medium has its own characteristics of structure in ecological flow-networks: Nutrient systems are generally more highly organized than carbon or energy systems.View full abstractDownload PDF (771K) -
Hiroshi Kanai, Noriyoshi Chubachi, Toshishige Takeda1991 Volume 111 Issue 12 Pages 631-636
Published: December 20, 1991
Released on J-STAGE: December 19, 2008
JOURNAL FREE ACCESSIn the literature there have appeared a lot of works with regard to acoustic emission (AE) signals observed in a frequency range below a few MHz. In this paper we describe a new system for measuring AE signals in the frequency range up to 100 MHz. By using piezoelectric thin-film transducers fabricated on the end surfaces of rectangular bars of glass samples which have been notched, the AE signals radiated from the crack can be detected during conventional three point bending test. The output signal of each transducer is amplified and A/D converted at a sampling rate of 200 MHz. The power spectrum of each AE signal and the coherence function between the two signals are obtained by using a computer. The new AE measurement system in VHF range developed here can be applied in a new research field to be called micro-AE spectroscopy.View full abstractDownload PDF (1491K) -
Osamu Tabata, Hajime Inagaki, Susumu Sugiyama, Hideo Yamada1991 Volume 111 Issue 12 Pages 637-644
Published: December 20, 1991
Released on J-STAGE: December 19, 2008
JOURNAL FREE ACCESSA monolithic pressure-flow sensor combining a silicon piezoresistive pressure sensor and a thermal type silicon flow sensor was fabricated and its characteristics in air were investigated. At 0_??_1 kg/cm2 and 0_??_75°C, the pressure measurement characteristics such as sensitivity, thermal sensitivity shift, nonlinearity and thermal zero shift were the same as those of a conventional piezoresistive pressure sensor. Reproducible flow output without hysteresis was obtained at 0_??_150 g/s. It was clarified from the flow visualization experiment that a bending observed in the flow calibration curve at the flow rate of 15_??_80 g/s was due to a separation bubble formed at the front of the chip. The flow output showed large measurement error during the transient change of air temperature and it also decreased with the increasing of sensor support temperature. These characteristics were well explained by thermal balance at the heater of the flow sensing part.View full abstractDownload PDF (2187K) -
Jun'ichi Yamaguchi, Takahiro Fujishiro, Masato Nakajima1991 Volume 111 Issue 12 Pages 645-651
Published: December 20, 1991
Released on J-STAGE: December 19, 2008
JOURNAL FREE ACCESSIn shape identification of the 3-D object using a vision sensor, it is important that the system is insensitive to the translation and the rotation of the object. The authors have developed a system for quickly identifying the shape of the 3-D object, using a dot-matrix-like bright spots projection. In the system, the range data is classified, using the 3-D information of the bright spot. The polar coordinates transform is performed in the frequency domain of the classification data. A pattern of invariance to the translation and the rotation of the classification data is produced, using the power spectrum of the transformation data. The pattern is identified by a multi-layered neural network.
This paper describes the method of the shape identification of the 3-D object, using the dotmatrix-like bright spots. The results of the experiments, which were performed to verify the effectiveness of the proposed method, are discussed.View full abstractDownload PDF (2805K) -
Takehiro Mori, Hideki Kokame1991 Volume 111 Issue 12 Pages 652-653
Published: December 20, 1991
Released on J-STAGE: December 19, 2008
JOURNAL FREE ACCESSDownload PDF (717K)
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