Saturation measurements on electron spin resonance signals in amorphous silicon films

The dependence of the electron spin resonance signal intensity on the microwave magnetic field was investigated for amorphous silicon prepared by r.f. sputtering. The spin-lattice and the spin relaxation times T₁ and T₂ were determined by a new saturation method. As a result it is suggested that the electron spin resonance linewidth is determined by g-factor anisotropy, that T₂ is 10–100 times longer than the T¹₂ determined from the linewidth, that T₁ for samples annealed at below about 250°C is proportional to T^-1.9 and that most of the spins for samples annealed at above 400°C are probably due to dangling bonds in amorphous regions surrounding crystallites newly produced in the process of crystallization.     

Prospects for Automation of the Aluminum Reduction Process

A discussion of a control system for power circuits, continuous feeding of alumina, anode level control, etc., with reference to the possibility of introducing computers to the pot operation.     

Induction of platelet-activating factor in mice by intravenous administration of a neutral fraction of bakers' yeast mannan

A neutral subfraction of mannan of bakers' yeast (WNM) was found to show a lethal effect in mice when administered intravenously. Symptoms caused by intravenous (i.v.) administration of WNM resembled those resulting from the administration of platelet-activating factor (PAF). CV-3988 and ONO-6240, selective PAF antagonists, prevented hypotension and death caused by the administration of WNM or PAF. A β-adrenoceptor agonist was shown to prevent death caused by WNM, whereas propranolol increased the lethal activity of WNM. Intravenous administration of WNM into mice produced PAF in gall bladder fluid which was determined by platelet aggregation assay. The findings indicate that WNM is able to induce PAF in mice and that the resultant PAF may participate in the WNM-induced lethal activity observed in mice.     

Speed control system and design of resonant system with disturbance observer

In industrial motor drive systems such as industrial plants and industrial robots, a torsional vibration often is generated because of the elastic elements in torque transmission. This vibration makes it difficult to achieve quick responses of speed and may result in damage to the plant. Such systems simply are modeled as a two mass system. The shaft torque feedback system with the disturbance observer, which is called “resonance ratio control,” is proposed to suppress the vibration for the two-mass system. In this paper, the design of controller gains in the shaft torque feedback system is examined considering not only the control performance such as the vibration suppression and dynamic responses, but also the robust stability against the noise and the model uncertainties. This paper shows the validity of the control system and the examinations by several experiments.     

Rates of gas absorption with interfacial turbulence caused by micro-stirrers

Rates of absorption of CO₂ into water, a 0.2 mol/L NaOH solution and a 40 wt% glycerol solution with and without the interfacial turbulence caused by micro-stirrers, made of a magnetic material, were measured with use of a stirred vessel with known gas-liquid interfacial area. The effect of the interfacial turbulence on the rate of gas absorption was remarkable in the lower range of the bulk turbulence. The enhancement factors due to the interfacial turbulence were calculated with use of the age distribution function of the Danckwerts type and they agreed well with the experimental results.     

Electrical properties of manganese doped Ga1−xInxAs grown by liquid phase epitaxy

Mn-doped Ga_1?xIn_xAs crystals (0 < x < 0.25) have been grown by the LPE technique, and the doping characteristics and electrical properties of the layers have been studied by Hall measurement. The distribution coefficient of Mn has been found to depend on the substrate orientation. The acceptor enerby level is about 77 meV and is comparable to that of Mn-doped GaAs. p-n junction diodes with high InAs compositions, grown using the step grading technique, showed a diode factor of 2. Electron diffusion lengths greater than 3μm have been measured in these Mn doped layers.     

Development of Arm Equipped Single Wheel Rover: Effective Arm-Posture-Based Steering Method

We have been proposing a new planetary rover system named SMC Rover. This system consists of one main body and detachable units, which can work as child rovers, and also become driving units of the main body. Each detachable unit named Uni-Rover consists of a single manipulator mounted on a wheel. Prototype models of the Uni-Rover and the SMC Rover have been already developed. This paper describes a new method of trajectory modeling for the Uni-Rover using the relation between arm posture and turning radius. At first, an intuitively recognizable model which uses zero slip angle is introduced. However, because this intuitive model has some problems, a new solution which considers the loss of friction on the wheel and on the caster is also discussed. The validity of the presented method is verified by experiments with an actual mechanical model. Moreover, an effective steering method which considers the margin of the energy stability is introduced.Kazuhiro Motomura is a Ph.D candidate at the Tokyo Institute of Technology (Tokyo Tech). In 2001 he was admitted to skip the fourth grade of the bachelor course in the Department of Mechano-Aerospace engineering at Tokyo Tech to enterthe master course in the Department of Mechanical and Aerospace Engineering at the same Institute. He received the B.E. degree in National Institution for Academic Degrees an University Evaluation in 2002, and received the M.E. degree in the Department of Mechanical and Aerospace Engineering at Tokyo Tech in 2003. He has been a research fellow of the Japan Society for the Promotion of Science from 2004. He awarded the Incentive Award for the presentation in the 17th RSJ Annual Conference in 2001, and the Finalists for the Best Video Award in the IEEE International Conference on Robotics and Automation in 2003. His research interests include design of robotic mechanisms and control of mobile robots. He studies about the development of planetary rovers.Atsushi Kawakami awarded the chance to skip fourth gradein the bachelor course of Department of Mechano-Aerospace engineering in Tokyo Institute of Technology, and entered the master course in 1997. He received the M.E. and Dr. E. degrees in Department of Mechanical Engineering Science in Tokyo Institute of Technology in 1999 and 2003, respectively. From 2003, he is a post-doctoral researcher. His research interest is in design of robotic mechanisms. He studies about the development of planetary rover. He awarded the Incentive Award for the presentation in the 17th RSJ Annual Conference in 2001, and the Finalists for the Best Video Award in the IEEE International Conference on Robotics and Automation in 2003. He also acts as an organizer and lecturerin several hands on robots competitions that aim at the promotion and education for the beginners.Shigeo Hirose was born in Tokyo in 1947. He received the B. E. degree with first class honors in Mechanical Engineering from Yokohama National University in 1971, and the M. E. and Dr. E. degrees in Control Engineering from the Tokyo Institute of Technology in 1973 and 1976, respectively. From 1976 to 1979 he was a Research Associate, from 1979 to 1992 an Associate Professor and since 1992 he has been a Professor in the Department of Mechanical and Aerospace Engineering at the Tokyo Institute of Technology. He is the Fellow of both IEEE and Japanese Society of Mechanical Engineers. His research interest is in design of novel robotic mechanisms and its control. He awarded more than 30 prizes from academic societies; these include the first Pioneer in Robotics and Automation Award in 1999 and Best Conference Paper Award in 1995 both from IEEE Robotics & Automation Society. Prof. Hirose has published more than 200 academic papers as well as several books, including Snake Inspired Robots (Kogyo-chosakai Publishing Co. Ltd, 1987, in Japanese), Robotics (Shokabo Publishing Co. Ltd., 1987, in Japanese), and Biologically Inspired Robots (Oxford University Press,1993).     

A New Approach to Humanitarian Demining

Landmines can deprive whole areas of valuable resources, and continue to kill and cause injuries years after the end of armed conflicts. Armored vehicles are used for mine clearance, but with limited reliability. The final inspection of minefields is still performed by human deminers exposed to potentially fatal accidents. The aim of this research is to introduce automation as a way to improve the final level of humanitarian demining. This paper addresses mobility and manipulation, while sensing, communication and visualization shall be discussed in detail in a subsequent paper. After analyzing the merits and limitations of previous works, a new approach to tele-operated demining is considered, using off-road buggies equipped with combustion engines, and taking into account actual field requirements. Control of the automated buggies on rough terrain is also discussed, as well as the development of a new weight-balanced manipulator for landmine clearance operations.Paulo Debenest received the B. Eng. degree in mechanical engineering (major in automation and systems) from Polytechnic School of the University of São Paulo (EPUSP), Brazil, in 1998, and the M. Eng. degree in mechanical and aerospace engineering from Tokyo Institute of Technology (Tokyo Tech), Japan, in 2002. He is currently working toward the Ph.D. degree in mechanical science engineering at Tokyo Tech and member of IEEE. His current research activities include development of demining robots and mechanical design of machines for field applications.Edwardo F. Fukushima is an assistant professor in the Department of Mechanical and Aerospace Engineering at Tokyo Institute of Technology (Tokyo Tech). He received the B. Eng. degree in electric engineering (major in electronics and telecommunications) from Federal Center of Technological Education of Paraná (CEFET-PR), Brazil, in 1989, and M. Eng. degree in mechanical science engineering from Tokyo Tech in 1993. In 1994 he became a research associate in the same institute. During Sept.–Dec. 2001 he has been a Visiting Researcher at Stanford University, and during Aug.–Sept. 2004 Visiting Scientist at University of Zurich. He is also member of RSJ. His current research activities include development of demining robots, design of controllers for intelligent robots, and development of new brushless motors and drives.Yuki Tojo is a masters course student in the Department of Mechanical and Aerospace Engineering at Tokyo Institute of Technology (Tokyo Tech). He received the B. Eng. degree in mechanical and aerospace engineering from Tokyo Tech in 2003. His research interests include design and control of weight-compensated manipulator on mobile platform. He is also member of RSJ.Shigeo Hirose was born in Tokyo in 1947. He received his B.Eng. Degree with First Class Honors in Mechanical Engineering from Yokohama National University in 1971, and his M. Eng. and Ph.D. Eng. Degrees in Control Engineering from Tokyo Institute of Technology in 1973 and 1976, respectively. From 1976 to 1979 he was a Research Associate, and from 1979 to 1992 an Associate Professor. Since 1992 he has been a Professor in the Department of Mechanical and Aerospace Engineering at the Tokyo Institute of Technology. Since 2002, he has been Honorary Professor in Shengyang Institute of Technology, the Chinese Academy of Sciences. Fellow of JSME and IEEE. He is engaged in creative design of robotic systems. Prof. Hirose has been awarded more than twenty prizes.