Showing papers by "Tokyo Institute of Technology published in 1979"

Strongly Stable Stationary Solutions in Nonlinear Programs.

Abstract: Publisher Summary This chapter focuses on strongly stable stationary solutions in nonlinear programs. Many studies have been made on the stability or the sensitivity of local minimum solutions to parametric programs. Those studies mainly discussed the continuity of the minimum value of the objective function, the continuity of the set of minimum solutions and/or the continuity of an isolated local minimum or stationary solution with respect to a small change of the parameter vector. In the case where the strict complementarity does not hold, the approach based on the standard implicit function theorem for continuously differentiable maps cannot be used. Various lemmas and theorems are discussed in the chapter. Stationary index, s-stable local minimum solutions, and degenerate s-stable stationary solutions are discussed. An application to a class of continuous deformation methods is reviewed.

The vetoers in a simple game with ordinal preferences

Abstract: We consider a core of a simple game with ordinal preferences on a set of alternative outcomes Ω. When a player's strict preference relation takes any logically possible form of acyclic binary relation on Ω, necessary conditions for a simple game to have a nonempty core are given. If Ω is a finite set, the conditions are also sufficient. Further some related results are obtained.

Noise properties of injection lasers due to reflected waves

Abstract: This paper describes the theoretical investigation of the origin, qualitative, and quantitative properties of the low frequency noise appearing in the light output of the laser diode, which is strongly coupled to optical fibers. This kind of noise has caused serious problems for reliable optical communications, especially for analog-modulation systems. It is shown that there are two different phenomena which generate such noise. One of them is the double cavity state, and the other is the external light injection state. The cause of our noise considered in the double cavity state is the phase variation due to the variation of the equivalent length between the laser and the reflection point generated by mechanical vibrations. On the other hand, the cause in the external light injection state is the random generations of locking and unlocking states due to the frequency variation (or mode jumping) caused by the variation of the internal temperature of the laser diode. We conclude from our theory that an effective method to reduce such noise is to operate the laser diode at well above the threshold current. The complete elimination will be attained by use of the optical isolator inserted between the laser diode and the transmission lines.

Low temperature synthesis of a monolithic silica glass by the pyrolysis of a silica gel

Abstract: The reaction process in the pyrolysis of silica gel has been investigated as the basic study on the low temperature synthesis of monolithic glass from a metal alkoxide. A large volume change which may cause stress-induced fracture of a gel occurred in the following process stages: (a) the decompostion of residual organic compounds into carbon dioxide (300 to 500° C); (b) small pore collapse (400 to 500° C); (c) larger pore collapse (700 to 900° C). A fracture-free monolithic silica glass was successfully prepared from a dry silica gel formed by the hydrolysis of silicon methoxide by careful heat-treatment. The properties of the synthetic silica glass were similar to those of commercial vitreous silica.

Amperometric estimation of BOD by using living immobilized yeasts

Abstract: A microbial electrode consisting of immobilized living whole cells of yeasts, porous membrane and an oxygen electrode was prepared for continuous estimation of biochemical oxygen demand (BOD). Immobilized Trichosporon cutaneum was employed for the microbial electrode sensor for BOD. When a sample solution containing the equivalent amount of glucose and glutamic acid was injected into the sensor system, the current of the electrode decreased markedly with time until steady state was reached. The response time was within 18 min. A linear relationship was observed between the current decrease and the concentration below 41 mg l − of glucose and 41 mg l − glutamic acid (5-day BOD 60 mg l −). The current decrease was reproducible within ± 6% of the relative error when a sample solution containing 27 mg l − of glucose and 27 mg l − of glutamic acid (5-day BOD 40 mg l −) was employed. The microbial electrode sensor was applied to untreated waste waters from a fermentation factory. Good comparative results were obtained between BOD estimated by the microbial electrode and that determined by the conventional 5-day method (regression coefficient was 1.2). Furthermore, the effect of various compounds on BOD estimation was also examined. The current output of the microbial electrode sensor was almost constant for 17 d and 400 tests.

A Pulsewidth Controlled AC-to-DC Converter to Improve Power Factor and Waveform of AC Line Current

Abstract: As a method for improving power factor and waveform of ac line current drawn by an ac-to-dc converter a new pulsewidth controlled converter is proposed, its commutation mechanism is described, and experimental results are given which show a good power factor, a good waveform of the line current, and a wide adjustable range of dc output voltage.

A condition of single longitudinal mode operation in injection lasers with index-guiding structure

Abstract: A condition for single longitudinal mode operation (SMO, for short) of index-guided injection lasers is given theoretically and supported by experiment. For SMO, the transverse higher modes must be cut off by using a narrow-width index-guiding waveguide. Inclusion of the spontaneous emission into the lasing field must be reduced by using a thinner active region. In terms of the impurity concentration of the active region, the undoped case is the most stable for temperature variation. A heavily doped active region may also produce SMO. The thermal resistance must be reduced to increase temperature stability. MO with a fixed lasing wavelength is experimentally obtained by temperature control up to an injection current of twice threshold.

Anisotropic electrical conductivity of partially oriented polyacetylene

Abstract: : Partial orientation of the fibers in polycrystalline films of (CH)x leads to significant improvement in the transport properties and to the introduction of electrical anisotropy.

Useful visual field size for pattern perception

Abstract: The useful visual field size at each fixation in a pattern was investigated by artificially supplying various visual field sizes on a TV display. The degree of pattern perception was measured in terms of recognition memory for pictures, and the speed of processing pictures was determined as a function of field size. A serious deterioration in the perception of pictures occurred as the visual field was limited to a small area around the fovea (about 3.3° × 3.3°), processing speed becoming extremely slow. Speed increased gradually as visual field size became larger, to reach a certain level beyond which no further increase was observed. The visual field size at this asymptotic speed was called the useful visual field and was found to be about 50% of the entire pattern size. Analysis of eye-movement records demonstrated that in terms of the useful visual field, the scanning characteristics of the eye over the pattern occurred in a heavily overlapping manner to assure good perception of the pattern.

IMMUNOFLUORESCENT STUDIES ON THE LOCALIZATION OF TYROSINE HYDROXYLASE AND DOPAMINE-β-HYDROXYLASE IN THE MES-, DI-, AND TELENCEPHALON OF THE RAT USING UNPERFUSED FRESH FROZEN SECTIONS

Abstract: Distributions of tyrosine hydroxylase (TH) and dopamine-β-hydroxylase (DBH) in the rat brain were examined using immunofluorescent staining on unperfused fresh frozen sections. TH-positive and DBH-negative dopaminergic neurons were observed in the anterior hypothalamic nucleus. In other hypothalamic nuclei such as ventromedialis, dorsomedialis, and posterior hypothalamic nuclei, a few dopaminergic neurons were also observed.Our immunofluorescent results with unperfused fresh frozen sections indicated that TH or DBH was mainly localized in the cell bodies of catecholaminergic neurons and that small amounts of the enzymes were distributed in the nerve terminals. Although it had been reported that the amine enzymes existed in nerve terminals as well as in the cell bodies by using paraformaldehyde perfused sections, the fluorescence observed in nerve terminals might be produced not only by the amine enzymes but also by amines themselves.

A Study on the Application of the Two–Color Method to the Measurement of Flame Temperature and Soot Concentration in Diesel Engines

Abstract: Results are presented of optical measurement of the flame temperature and KL factor (soot concentration) in a direct injection diesel engine using the two-color method. In the latter stages of combustion, the infrared two-color method gave a lower value than the visible two-color method, the difference being enhanced with crank angle advancement. The KL factor value obtained by the visible method was about half that of the infrared method. These differences were caused by the alpha index (wavelength dependency of flame emissivity) change in the infrared region during the combustion period; the effect at both wave lengths of uneven distributions of temperature and soot concentration along the optical path; and the effect of the reflection of the opposite wall on the infrared method. The optical characteristics and other instrumentation problems of the two-color method at both wavelengths are also discussed.

Microbial electrode sensor for alcohols

Abstract: A microbial electrode consisting of immobilized microorganisms, a gas permeable Teflon membrane, and an oxygen electrode was prepared for the continuous determination of methyl and ethyl alcohols. Immobilized Trichosporon brassicae was employed for a microbial electrode sensor for ethyl alcohol. When a sample solution containing ethyl alcohol was injected into a microbial electrode system, the current of the electrode decreased markedly with time until a steady state was reached. The response time was within 10 min by the steady state method and within 6 min by the pulse method. A linear relationship was observed between the current decrease and the concentration of ethyl alcohol below 22.5 mg/liter. The current was reproducible within ± 6% of the relative error when a sample solution containing 16.5 mg/liter ethyl alcohol. The standard deviation was 0.5 mg/liter in 40 experiments. The selectivity of the microbial electrode sensor for ethyl alcohol was satisfactory. The microbial electrode sensor was applied to a fermentation broth of yeasts and satisfactory comparative results were obtained (correlation coefficient 0.98). The current output of the microbial electrode sensor was almost constant for more than three weeks and 2100 assays. A microbial electrode sensor using immobilized bacteria for methyl alcohol was also described.

Direct measurements of the stiffness of echinoderm sperm flagella

Abstract: 1. The stiffness (flexural rigidity) of some echinoderm sperm flagella was measured, using a flexible glass microneedle. 2. Values of 0.3-1.5 × 10−21 N m2 were obtained for the stiffness of live flagella which were immobilized with CO2-saturated sea water. 3. The immobilized live flagellum was uniform in stiffness along its entire length, except in a particular plane of imposed bending in which flexible regions were observed. 4. Demembranated flagella (Hemicentrotus pulcherrimus) in an ATP-free solution were about ten times stiffer (1.1 × 10−20 N m2) than immobilized live ones (0.5-0.9 × 10−21 N m2). The stiffness was decreased by addition of ATP to the solution and became equivalent to that of live ones when the solution contained 10 mM ATP. 5. In the demembranated flagella, the effects of ADP and ATP on the stiffness were similar. Other nucleotide phosphates and inorganic phosphate did not reduce the stiffness. 6. Young9s modulus of microtubules is estimated to be 2.5 × 109 Nm2 on the basis that the microtubules have no tight connexion with one another in immobilized live flagella.