The underwater is fascinating fields for stand-alone and autonomous robots. They can enjoy swimming in the 3-dimensional world free from the restriction of gravity force. It is not easy, however, to construct reliable control systems for them which should be operated in the unknown and ever changing environment. A newly developed “Self-Organizing Neural-Net-Controller System (SONCS)” is installed in the robot's brain. It can generate by itself an appropriate controller for swimming without assistance of superviser. The procedure of generation involves learning robot's dynamics associated by a premature Fuzzy controller, evaluation of swimming performance, and modification of controller to pursue a specified mission. The advantage of SONCS is demonstrated through free swimming tests in a pool. SONCS succeeds in constructing a pretty good controller to maneuver the PTEROA robot keeping constant depth and pitch as a result of several times of adaptation.
In spite of the recent and much progress in the optical components and electronic devices, the radiation-resistant diagnostic devices for nuclear fusion machines are still highly required. The irradiation tests with fusion neutron were carried out by using RTNS-II (Rotating Target Neutron Source-II) at LLNL (Lawrence Livermore National Laboratory) in California, USA. The principal objective in demonstrating the radiation effects with 14MeV neutron on various devices is to determine the hardness level expressed in the maximum fusion (14MeV) neutron fluences at which their principal performance degrades 10 per cent. The optical components and electronic devices used in present work are the optical fibers, photoelectric devices, electronic devices and radiation detectors. The hardness levels for various optical components and electronic devices are given. These data may be used for the estimation of lifetimes of optical components and electronic devices for fusion diagnostics which will be installed in fusion machines.
This is a review of Photoacoustic (PAS) measurement using transparent transducer of semiconductor materials. This technique is very sensitive to detect a PA signal because the light is illuminated to the sample surface through a transparent piezoelectric transducer (LiNbO3) and the PA signal is detected directly from the transducer. In this review the generation mechanisms of PA amplitude and phase signals for layered semiconductor materials (GaInP/GaAs) are experimentally clarified. Then, a theoretical analysis of generation mechanism of PA signal is presented and the validity of the theory is clarified by the experimental results. Finally, the thermal conductivity of InP is estimated by using both the theory and the experiment.
Germanium and aluminum have been chosen as model substances both for ion-beam-assisted thin film deposition(IBAD) and for reactive ion-beam-assisted deposition(RIBAD) and the qualities of the films(Ge, GeN, Al, AlN) have been examined systematically in the present study. In cases of Ge and Al films formed by irradiating inert-gas ions in IBAD, the highest quality of the films has been obtained under a certain optimum ion-to-atom arrival-rate ratio(ion-to-atom ratio) and the ion energy. The optimum ion-to-atom ratio for IBAD is found to be much smaller than unity for both Ge and Al films. Formation of nitrides(GeN, AlN) by RIBAD has been confirmed by the IR absorption spectra.
This paper presents the correlation between the microscopic stracture and magnetic properties on a-like Co-ferrite films, which prepared by oxidation of a-like thin film of Fe-Co composites from evaporation method. It has been found that the magnetic properties of oxide films is different depend upon the temperature of heat treatment and whether an external magnetic field is existed or not in oxidation process. In practice, the magnetic oxide films prepared in field presented explicitly the magnetic anisotropy of perpendicular direction and Kerr effect.
New glasses recently developed are described. Recent progress in electronics and optoelectronics incited developments of new glasses. Defferences in the concept of “conventional glass” and “new glass” are pointed out first and some examples of new glasses are presented: fluoride glass, rapidly quenched glass, high purity silica glass by sol-gel process, optical memory glass and non-linear optical glass.
Crystalline Ge is superior to Si in the points that the mobility of carriers is higher and the recrystallization temperature is lower. As the energy gap is small, it could be applied to the optical sensor in infrared region. The amorphous thin films, however, have not been applied to the devices because the films involve high density of dangling bonds. To terminate the dangling bonds, the hydrogen atoms are introduced in the films. The hydrogenated amorphous Ge thin films are prepared by glow discharge method, ECR plasma CVD method and reactive sputtering method. Here, we introduce the fundamental properties of hydrogenated amorphous Ge including energy band model, which were obtained so far.
Mechanical alloying (MA) has been recognized as a novel method for synthesizing amorphous materials by the solid state reaction. So far, alloy systems amorphized by MA are characterized by a negative heat of mixing. This is because a system with a negative heat of mixing possesses potentially a chemical driving force promoting the amorphization. More recently, however, the formation of an amorphous phase by MA has been reported in the Cu-Ta system 3, 4) with a positive heat of mixing. Here a chemical driving force is no longer expected and, instead, the energizing process has been proposed to be involved in the formation of the amorphous phase. The amorphization by MA for mutually immiscible systems which are characterized by a positive heat of mixing has been studied by neutron diffraction, EXAFS and DSC measurements.
Unidirectional carbon fiber reinforced SiC, B4C and mullite composites have been fabricated by a process consisting of slurry impregnation followed by hot pressing. Identification of crystal phase and observation of metallographie structures in the composites were carried out. Mechanical properties such as flexural strength and fracture toughness were measured and discussed in connection with the metallographic structures.
The cooling curves of quenching oils are obtained using the JIS K 2242 method. The cooling performance of a quenching oil is able to be controlled by varied vacuum conditions, eg. hardness increase of steel is varied according to the vacuum pressure. When insufficient hardness of steel is produced, right selection of vacuum pressure in the vacuum heat treatment may help to result in required hardness of steel. In acutual field operation we can obtain satisfactory hardness and distortion of steel if we select an appropriate quenching oil in combination with right vacuum condition.
During the last few years the observations of astrophysical neutrinos have been made with a method which provides the arrival time, the arrival direction and the energy spectrum of these neutrinos. Our Universe is discussed in view of this new born Observational Neutrino Astrophysics.