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This paper studies the nonlinear state estimation for the system of hydrologic cycle in the basin of Lake Biwa. The internal states of the system are water storage levels, which can not be measured directly but eventually play an important role in calculating the amount of water in each process of the cycle such as snowmelt, snowpack, runoff, and evapotranspiration. Since the hydrologic process from precipitation to runoff has nonlinear characteristics, system-theoretic nonlinear state estimation technics are applied to the system in order to estimate unobservable water storage levels. As a result, some comparisons among estimation errors for various nonlinear state estimation methods are obtained.

This paper describes the scope of the railway commuters' area around the station in a suburban area by geometric approach. First, under the assumption that the railway line has a infinite numbers of stations, the area that railway line covers is analyzed. The residents in this area are expected to use railway in making a trip to the city center. On the other hand, the residents outside the area make a direct trip to the city center without mode mix. Secondly, we pay attention to a microscopic state between stations along the railway line. The boundary line between the area that the station covers and that of neighboring station is resulted to be a hyperbola.

A model of trip chaining in a linear city is developed in this study using the concepts of time-space prism and utility maximization. The unique features of the model include the followings: (a) The potential utility of the time spent at home is evaluated using the area of the prism formed by the sojourn at home; and (b) The concept of the fixed utility is introduced as a measure of the benefit derived by the action of returning home after persuing additional activity. Several properties of a worker's choice of a trip chain were derived. These include the fact that the more the duration of the activity, the distance between the work and home location, and the speed of the travel mode used, the more the home-based trip chain chosen. This fact also agrees with empirical results. Future directions of the trip chain research are also discussed.

There are various methods of diffraction analysis by linear wave theory. In this report, works dealt with diffraction problems are classified according to analytical methods and feature of these is shown with a view to be referred to future works.

The lime stabilization tests were performed to investigate the effects of treat ting on the physico-chemical and strength characteristics of Onomichi clay subjected to lime addition. The trace of treatment effects were made clarify by X-ray diffraction, unconfined compression, consistency test, and etc. The main results obtained are as follows; (1) The increase in strength of the clay for the lime stabilization treatments is attributed to the permanent cementing action between soil particles of the new crystalline minerals which are formed in consequence of the chemical reaction of the lime and activated Al_2O_3 and SiO_2 in the soil; (2) CaCO_3 has been little effect with regard to increments of the strength; (3) It was found that the optimum mixed ratio have been related to the consistency; (4) Unconfined compression test make used of a.index of the treatment effects; (5) A change of integrated intensity for montmorillonite obtained by the X-ray diffraction test could relate ions exchange with pozzolanic reaction.

Blast o-plastic shear buckling strength and post-buckling behavior of square plates with circular holes are investigated experimentally. The plates are subjected to uniform inplane shearing deformations and clamped along plate edges. The circular holes are centrally located. Ratios of the hole diameter to the plate length, d/l, are 0.3, 0.5 and 0.7. Elastic stresses along the plate edges and the hole edges show reasonable agreement with the results from finite element analysis except corners of the plates. For elasto-plastic buckling load, comparison of test with analysis shows good agreement. Experimental ultimate loads of the plates with the ratio d/l=0, 0.3, 0.5 and 0.7 are 1.64, 1.62, 1.79 and 1.87 times of the elasto-plastic buckling load, respectively.

This study was conducted to know the temperature sensation of human skin to the infrared radiation in different wavelength ranges. The temperature sensation of skin of 155 test subjects to the same values of irradiance obtained from three band radiators (A: 0.72-2.7μm, B: 1.5-4.8μm and C: 6-20μm) are investigated. The results are as follows: (1) Mid and far ir radiation gives stronger warm sensation to the almost of subjects than near ir radiation. (2) Near ir radiation gives mild warm sensation, but mid and far ir radiation gives sore warm sensation. (3) There are no differences of temperature sensation between male and female, and among age groups. (4) Mid and far ir regions beyond 2 μm of wavelength the temperature sensation of human skin is independent to wavelength. The facts mentioned above can be illustrated by the optical property and the Construction of human skin.

Distribution of the polyethylene-terephtalate film capacitors breakdown voltage is the minimum double exponential extreme value at the early period. When the heat worsen the property of the insulation film, the distribution of the breakdown voltage change to the maximum double exponential extreme value. The relation between the mode V_o of the breakdown voltage distribution and the temperature T (absolute temperature) is shown in next formula. V_o=A・exp (B/T), A and B is constant number. At the minimum extreme value distribution, relation between the breakdown voltage V and the probability F(V) having the breakdown voltage higher than V, is indicated in next formula. F(V)=exp. [(-exp. α(V-V_o))], where V_o is mode value.

Francesco di Giorgio Martini (1439-1501) is one of the trattatist on architecture and military architecture in Italian renaissance. There remain several manusciprts which are his own hand and other's, among which the latest onesircodice Magliabechiano II.1,141 (M) and codice Senese S.IV.4 (S) -reveal his matured way of thinking. Therefore on this paper the relation between his thought and Aristotelian philosophy concerned with these two codices is considered, because there are many phrases cited from Aristotle's Metaphisica, Phisica, Ethics etc. The conclusions of this paper are next ones: 1) His point of view is, generally based on the Aristotelian Philosophy, that the human life is always oriented to the good and the truth in the ordinary life, the real life, not in the world of after death, so his practice and fabrication also oriented to these good and truth. 2) His motif of these manuscripts is to give the universal point of view on architectural theory, so the method is, like Aristotle's, based on the inductive and positive way which is guided from the individual phenomena, individuality to the universal, universality. In this meaning the structure of his manuscripts has, influenced by the medieaval Christian teology, the dual polar structure, but also has the dynamic and open structure. 3) The meaning of his term "l'arte antigrafica" is the art to give principles on the architectural theory, both on the theory and technology, criticizing the phenomenal problems.

Time functions or wave forms which are generalized physical variables in a dynamical linear system are discussed on a basis of Taylor series expressions. A wave form is developed as a Taylor series formula which coefficients are decided by the differential equations and initial conditions of the system. Also, formula of both Fourier and Laplace transforms are deduced from the Taylor series of a complex function.

This article discusses the automobility from the points of view as follows; (1) urban transportation problems, (2) history of car, (3) car culture, (4) energy efficiency, (5) traffic management and (6) automobility in local cities. It is concluded that each city should take an original and own transportation policy against automobility.

Tensile fatigue strength of smooth steel plates with circular holes is investigated. Ratios of the hole diameter to the plate width, D/W, are 0.125, 0.25, 0.5 and 0.75. The fatigue strength in S-N curve is expressed by applied stresses in gross sections and average stresses in minimum sections. In case of the applied stresses, the fatigue strength of the perforated plates with D/W ratios 0.125, 0.25, 0.5 and 0.75 is 0.54, 0.52, 0.37 and 0.14 times of the unperforated plates at 3×10^6 cycles respectively. For the average stresses, the fatigue strength of the perforated plates preserves 0.66～0.77 times of the unperforated plates regardless of the hole sizes.

Spectral distribution of radiation of ceramic infrared radiators were measured using the filter type spectroradiometer, because the ceramic ir radiators were expected as an energy saving heater, but it was still unknown. Then it became clear that they were the thermal radiator which has high emissivity.

It was reported that the brittle fracture in plastic range at room temperature took place in the full scale tests of wide flange beam-to-column connections of which the thickness of column flanges were from 40mm to 60mm. It is very important to analyze this phenomenon, because the wide flange of heavy steel section is generally used in the construction of multi-story buildings. In general, the following factors seem to have influence upon brittle fracture; (1) material properties (grade of steel, change of material properties by welding, anisotropy of rolled steel, etc.) (2) temperature (transition temperature) (3) constraint intensity of plastic deformation (plane strain, dimensions of members, etc.) (4) residual stresses (by rolling and welding, etc) The brittle fracture is caused by superposition of these factors, and it is necessary to make clear how these factors affect on the brittle fracture. The former two factors can be estimated by the test of small specimen, but the latter two cannot be done by it, and they should be estimated by the test of large scale specimen. Therefore the authors examine the fracture toughness of welded beam-to-column connections of heavy steel section. At first stage we focused our attention on the former two factors, that is, (1) material properties and (2) temperature, and carried out the COD testing of small scale specimen which is little affected by the latter two factors.

Mitsuki district is located in the eastern part of Hiroshima, and lies along the Mitsuki river that flows into the Inland Sea of Seto. Mitsuki, therefore, was the important place for the trade of agricultural and marine products. In Mitsuki, some ancient houses remain now, and the Makita's house is the oldest one that was built in 1831. Makita's family had been the chief of the village. This house is very interesting to study, and is little corroded and reconstructed. In this study, the authors inquire into this house in detail and try to investigate how this house is affected by the history, the natural features, and the traditions of Mitsuki district.

In recent years, large offshore structures have been constructed. The characteristics of the wave diffraction are very important for obtaining the intensity and distribution of wave energy on the structure. The diffraction of linear plane water waves dealing with the multiple fixed vertical cylinders having large diameter is described in this paper. Under the consideration concerning with the separation distance of the cylinders, an approximate series solution is proposed for the analysis of the diffraction of wave. Using this theoretical approximate series solution, the diffraction coefficient, the height of water surface and the difference of phase of the wave are analyzed.

In adopting an conventional metrical study method for landscape evaluation, we developed an evaluating system for landscape. And using this system, we conducted a series of on-site experiments. As a result of the experiments, we obtained data concerning the factors that affect the landscape evaluation: roadside trees, billboards, road-widths, etc. We conducted improvement work with respect to those factors and, after the completion of such work, we carried out an evaluation on how the landscape was enhanced as a result of the improvement work, applying, once again, the evaluating system for landscape. In this way, we clarified the effectiveness and the practicability of the evaluating system for landscape. The experiments, as mentioned above, we conducted with regard to the construction work in Sakai-suji Avenue to improve the street landscape.

Elastic-plastic shear buckling of square plates with circular holes is investigated experimentally. The plates are subjected to uniform in-plane shearing deformations, and have clamed edges and centrally located circular holes. Diameters d of the hole are 0.3 l, 0.5 l and 0.7 l where l is length of plate edge. Comparison of test results with analytical results shows excellent agreement except d/l=0.3 in the buckling strength and relatively good agreement in elastic in-plane stresses.

A new apparatus which is automatically focused by means of a photoelectrical measurement of the quality of images is devised. The method of detection of a focus is one of those usually adopted, that is, when images projected onto a detector are brought into the best focus an output of the detector reaches an extremum. In this study, electrical circuits having two track-hold circuits as a main component are used. Two output values of the detector are differentiated periodically and this differential output reaches zero when the images are brought into the best focus. When a motor is driven by a voltage proportional to the output the lens stops at the best focus position. The apparatus is attached to a marketed enlarger and performances of the apparatus are evaluated with a newly developed method. It is clarified that performances of the apparatus are excellent. The apparatus which measure focusing performances is produced. The focusing time, the size and dispersion of the difference between lens position and best focus position are measured by the apparatus. As a result, it is clarified that the automatic focusing time is shorter than manual focusing time, while in point of correct focusing, there is no difference between the automatic type and manual one.

In this paper three prediction methods of hourly traffic volume are considered from the system-theoretic point of view. As a result, it is confirmed that the prediction method, which predicts hourly traffic volume a month ahead by use of annual, monthly, weekly, and hourly factors defined in traffic engineering, minimize the mean of prediction error.

We can't regard geometrical space as existential space. K. Morita divided concepts of space into six types of space according to the phase of exist, and in order to constitute the architectural theory as total, we must research the correlationships among them. I think, there is a possibility at a few phase to this aim, by the concpet of Kineasthes in phenomenology.

The present report discusses various problems regarding the design of (1) System planning, (2) System management planning, (3) System shift planning, and details the cost study of Data processing in Administrative business work.

There are a lot of factories manufacturing rerolled steel bars for concrete reinforcement at Tomono-ura in Fukuyama City of Hiroshima. These rerolled steel bars are manufactured by rejects in the iron works. It is said that they have some problems in quality because the rejects include various kinds of steel from mild steel to high tensile steel. In general, the quality control is necessary to ensure the quality of products. In this paper, the author introduced the Rockwell hardness (B scale) test for the quality control of rerolled steel bars and carried out various tests for rerolled steel bars. The test results are described in detail herein.

Elastic-plastic shear buckling of square plates with square holes is investigated experimentally. The plates are subjected to in-plane shearing deformations, and have edges supported stiffeners which Have three kind of thickness. Ratio of the square hole length to the plate length, a/1, are 0.3, 0.5 and 0.7. Experimental stresses along the plate edges show good agreement with finite element analysis except the largest hole a/1=0.7 in which the finite element mesh is relatively coarse. At the hole corners where there are maximum stress concentration, experimental stresses are much larger than the analysis in larger holes. Thicker edge stiffeners decrease the stress concentration at the hole edges and increase the buckling strength of the perforated plates rather than the unperforated. Experimental buckling strength of perforated plates with the ratio a/1=0.3, 0.5 and 0.7 is 0.51, 0.35 and 0.16 times of the unperforated plates respectively.

The masonry construction has been used for about one hundred years since it was brought to Japan in the beginning of Meiji Era, and it suffered considerable damage at the Kanto Earthquake of September 1, 1923. The masonry construction, originally, was developed in the Europe Continent, where is few earthquake, therefore it is not earthquake resistent. It is said, however, that the reinforced concrete block construction is safe against the earthquake, and it is reported that it suffered few damage during the Miyagi-ken Oki severe earthquake in 1978. On the contrary, a lot of fences of concrete block construction severely suffered damages during the same earthquake. These structures were easily collapsed because of poor construction. The strength of concrete block construction mainly depends on the workmanship of plas terers, and it is not desirable. The authors, therefore, develope a new construction method introducing the pre-stressing, i.e. the dry construction without mortar. The basic concept is to introduce the pre-stressing into the reinforcing steel bar, and by that menas, the concrete block structures can resist the bending moment and the shear force caused by earthquake. The bending moment and the shear force can be resisted by concrete and reinforcing steel bar as single reinforced concrete beam, and the friction between each block caused by the tensile pre-stressing of reinforcing bar, respectively. In order to investigate the restoring force characteristics of the newly developed concrete block construction, we carried out experimental work shown in Fig.-4, and the test results are also shown in Fig.-5～32. As the result, the new construction method can improve the workmanship of concrete block construction, and it can resist the repeated horizontal load sufficiently. The restoring force characteristics of it is considerably improved by dry construction in comparison with the wet construction.

The thermal emission properties of ceramic ir radiator in the wavelength regions 1.5 to 4.5, 8 to 12, 22 to 33, and 1.5 to 45 micrometers are described. Data are presented for alumina-titania, zirconia, enameled iron, pyrex, and quarts glass radiators, and they are all thermal radiator, any other emission (luminescence) are not detected. Finally, methods for detection of the broken radiator applying the thermal ir radiation of it are discussed.

Elastic-plastic shear buckling of square plates containing centrally located circular holes is investigated analytically. The plates are subjected to uniform shear stresses or uniform shear deformations. Ratios of the hole diameter to the plate length, d/l, are 0.15, 0.3, 0.5, 0.7,and 0.85. The influence of the circular hole and in-plane loading condition on buckling strength is considered on various sized holes. The results suggest that the buckling strength in the uniform shear deformations is higher than the unfiorm shear stresses in the elastic and elastic-plastic ranges. These phenomena are more remarkable in the clamped plates than the simply supported plates.

Recent progress of computers in personal use enables us to collect a large amount of numerical data through the analog-digital converter in relatively low cost and to analyze them in reasonable speed. To determine the dynamic characteristics of vibratory systems, vibration tests in steady state, such as model tests on the vibration table or the test to real structures excited by the exciting machine with rotating eccentric mass, are widely percecuted. From the amplifi cation and phase characteristics to the exciting force, natural frequencies and damping ratios of the system are estimated. It is necessary to draw a resonance curve during the percecution of the vibration tests for the next adequate operation. Data processing technique using computers can analyze the numerical values from the transducers attached to the members of the test objects in fast and high accuracy. In this report, we discuss real time data processing in vibration measurement using a personal computer with relatively low memory capacity. Computer programming technique written in assembly language, however, can reduce computation time drastically and the results of the analysis are shown graphically at once. Automatic data processing using a personal computer contributes greatly to get high accuracy of data analysis as well as the high efficiency.

In recent years, the number of automobiles registered in Japan is still increasing and thereby typical phenomena of a traffic jam of automobiles are now seen everywhere in city streets. In order to suppress a traffic jam, various schemes of traffic control are put in force: This paper proposes a technique of computation for the estimation of a spot traffic volume which may play an essential role in traffic control. At first a relation between the sample size and the distributions of sample mean and sample variance for the statistics of a spot traffic volume is discussed. In the second, a yearly statistical characteristics of the spot traffic volume is analyzed and, subsequently, monthly, weekly, and daily characteristics are investigated. Based on this analysis, a computation technique for the estimation of a spot traffic volume is proposed. Finally, by the use of hourly traffic volume data which were recorded at an observatory beside the Route 2 national main road in Fukuyama city, the computed estimation error for the proposed technique is examined.

A 2-terminal network may. be driven by a voltage or current source at the driving point, and the corresponding current or voltage may be measured. We call the resultant ratio the driving point impedance function Z (s) or the driving point admittance function Y (s), respectively, of the network. Taking typical forms of surge waves in distribution feeder systems, we explain a method to analyze these characteristics of the feeders, namely the fundamental electric elements of the feeders R, L, C, and their ratios. The analysis will contribute to the appropriate design of distribution feeder systems or to the improved standards for such design, in view of the increased significance of the response of high-frequency characteristics of distribution systems in recent technical developments.

An atmospheric trace gas monitor with a PbSnTe laser has been developed. The open, 1 m optical path in a single-folded configuration enables local and non-contact measurement in a portable apparatus. The accuracy depends on optical noise, and a technique in diode-current modulation was effective in suppressing it. Analysis of the system noise based on the experimental data was made and a 10 ms interval was sufficient to attain an accuracy 3 ppm for methane. Field measurements were made and a rapid fluctuation in the atmospheric methane density was recorded. Further, with the principle of this monitor, the non-contacting and temporally continuous measurement was made for radius of spherical flame front on the progress of a single combustion. Abundance of unburned spectrum at a time instant was obtained with using a chirping diode laser beam passing through the spherical vessel. Experimental results are compared with those calculated only from the pressure with using a theory of Lewis and von-Elbe as well as those obtained with ion probes. Results of three methods agree well when the initial pressure is low but do not at high pressure. This method has the advantage of the accuracy at the initial stage.

In the distribution of the sea surface radiation measured on the sea shore in the mid-infrared region, the peak value of radiation was observed near the sea line. Spatial distributions of the radiation were different with the meteorological conditions, but in every case it was confirmed that the peak value near the sea line was observed as the sea line brightening on the thermogram.

Magnetic flocs build up on a signle wire for red tide plankton and kaolin are reported using magnetic seeding method. Magnetic seeding material and coagulant used in this experiment are magnetite and PAC, respectively. The profile of magnetic flocs build up and the accumulation radius are strongly dependent on magnetite concentration, PAC concentration, pH, and magnetic field intensity. The appropriate values of magnetite concentration and PAC concentration at pH9.3 and a magnetic field of 3kOe are determined to grow the magnetic flocs build up for red tide plankton.

Elastic-plastic shear buckling of square plates with square holes is investigated experimentally. The plates are supported by extremely thick stiffeners, and subjected to in-plane shearing deformations through the stiffeners. Ratios of the square hole length to the plate length, 1/1, are 0.3, 0.5 and 0.7. For elastic stresses, finite element analysis shows good agreement with the experimental stresses at the hole edges and along the edges supported by the stiffeners. In this study, experimental buckling strength oi perforated plates with the ratios a/1 = 0.3, 0.5 and 0.7 is 0.78, 0.49 and 0.23 times of the unperforated plates respectively. For all the plates including the previous work, the elastic-plastic buckling strength increases with increasing the thickness of the stiffeners because of restiction of rotations and in-plane shearing deofrmations at supported edges.

As computers are now playing highly significant roles in our society, the education of information processing engineering becomes increasingly important. In order to meet the needs, the department of information processing engineering was newly founded in Fukuyama University in April 1986. In this department we emphasize not only the fundamental education, but also the education of image information processing. We summarize, in this report, the object and the contents of our edu cation, especially of software, the configuration of the computer system and some considerations on the intror duction of the system. We hope that this report will be of help to those who are intending to found similar departments.

In this paper, the discussion about details of the results of observation on distribution of the sea surface radiation near the sea line which the authors have mentioned in thenprevious paper, and image processing of the thermograms are described. (1) The high radiance area near the sea line widen in the summer, and the sharpness of its distribution curve becomes about five times in the winter. (2) The high radiance area near the sea line is the special phenomenon in mid-infrared region (8～13μm band). (3) A temperature inversive layer increases the width of high radiance area near the sea line and promotes the lowering of contrast. (4) The high radiance area may possibly be extinguished very much on the season that the atmospheric temperature of lower layer is as same as the sea surface temperature. (5) The thermograms with few contrast become easy to discriminate by the image processing of binarization. (6) The thermograms of the sea surface become easy to grasp the sea surface condition and to discriminate minute target with high radiance by the expressive method of radiance difference.

Fukuyama, a local city in the Chugoku district, locates in the so-called Fukuyama plain, which consists of the delta of the River Ashida and the lands reclaimed by drainage since the Edo period. The ground of the city is supposed to be so weak that the considerations on the soil ground will be necessary for the safety of the city against the future severe earthquakes. Based on the data on the composition of the soil layers and N-values of the standard penetration tests obtained from the boring tests in the city, the distribution of the weak soil layers such as clays and silts is discussed. From the observation of micro tremors of the surface ground at 34 primary and junior high schools in the city, the predominant periods or- frequencies of the ground are detected and the dynamic characteristics of the ground are also discussed.

This paper, is concerned with general equilibrium model of optimal supply of transportation facilities and optimal pricing to transport services. Strotz's work (1965) that studied optimal road supply and congestion toll on a single one-way road is developed to the more general case including competitive transport services. Here we consider two competitive roads, say free general road and toll-charged expressway, and public transport. Both optimum allocation of resources and optimal pricing to these three routes are discussed by use of general-equilibrium-theoretic approach. The conceptual framework used in the work is mostly the same as in the Strotz's model, but partially different. Major improvements are as follows: (1) time budget is introduced into the set of constraints of household utility-maximizing behaviour, (2) consumers (=trip makers) are faced to three competitive routes, so trip costs that were ignored in the Strotz's model are evaluated and fuel tax is also introduced into the model as a new financial source for transportation investments. Main results involve the so-called marginal cost pricing principle, e.g. the expressway's toll must be equated to the balance of the two marginal rate of substitution between trips and resource input to two roads. As for the public transport fare this principle also holds. Finally, a process for approaching general equilibrium solutions is illustrated.

Elastic-plastic shear buckling of square steel plates with circular holes is investigated experimentally. The plates are subjected to in-plane shearing deformations, and have edges supported stiffeners and centrally located circular holes. Ratio of hole diameter to the plate length, d/1, are 0.3, 0.5 and 0.7. Experimental stresses along the plate edges show good agreement with finite element analysis. At hole edges, experimental stresses are greater than the analysis. The edge stiffeners restrain the in-plane deformations and increase the buckling strength. Experimental buckling strength of perforated plates with edge stiffeners is shown between analytical results of uniform shear stress deformations and uniform shear deformations.

Very few cities and towns have as yet decided to introduce the EDP system for local administration after analyzing their administrative office work analysis ((1)motion study, (2)functional approach, and (3)behavior approach) on the basis of the numerical and other standards. In Otu city, an investigation has been made concerning: 1) jobs as an object of the EDP system 2) possible styles to utilize the EDP system 3) an estimate of data processing cost and its data source is a report entitled "A Report of the Investigation Results regarding the office work Analysis in Otu city" in 1979. In this study, further investigations and studies are supplemented by "A Report on the plan to introduce the Data Control System in Otu city" in 1980. A study was made to determine how to handle problems related to the architecture of data control system, as well as on updated office automation. An approach was also made toward solving the various problems in implementing them.

Formulations of most generalized continuum mechanics have been based on a priori definition of directors except Eringen and his coworkers. Similarly we also have been trying to formulate the theory of general multi-directed continua, each material point of which has m single directors and n director polyads. The aim of this paper is to clarify the geometrical relation of directors and the physical meaning of director stresses and forces of general multi-directed continua by means of deriving directors from microscopical structures of an ideal model and reformulating director stresses etc. by the microscopical Cauchy's laws of motion.

It is widely considered that the earthquake activity in Chugoku district is relatively low and that severe earthquake seldom occurs in and near Chugoku area. From the historical point of view, however, not a few earthquakes which caused severe damage to building structures and human lives have occurred in the same area. Recent examples of the disastrous earthquakes are Hamada earthquakes (1872), Geiyo earthquakes (1905) and Tottori earthquakes (1943). The magnitude of them were grater than 7.1 and the cities near the origins suffered severe damages. From the survey of historical earthquakes that caused large damage in. Chugoku district, it is pointed out that the origins of them are concentrated on the narrow'coastal area in Tottori and Shimane prefecture facing Japan Sea and the sea area in Seto Inland Sea off Hiroshima called Aki-nada and Iyo-nada. Collecting the records of intensity of earthquakes felt in Chugoku district during these hundred years, earthquake activity is discussed from the epicenters and magnitude distribution. Although mean annual occurence rate of earthquakes shows that the earthquake activity now is in lower level than that of a few decade years ago, it is important to pay particular attention to future possibility of large earthquakes in order to minimize earthquake disaster.

This paper proposes an application of the optical Instability to an optical-waveform synthesizer. This device is featured with a sub-nanosecond speed achieved with employing both GaAs- and Si-optoelectronic switches as photo detector. A result of experiment for an optical pulse shaping is also given.

In this paper numerical method using the Galerkin weighted residuals approach is applied to analyze the flow around a cylinder. Using the results of numerical analysis the distributions of the velocity vectors and the equi-velocity contours are shown on a color graphic display. And a vortex behind a cylinder is also, shown in the mathematical expression with an equiangular spiral function.

Elastic shear buckling strength and post buckling behavior of thin square plates with circular holes are investigated experimentally. The plates are subjected to uniform in-plane shearing deformations and have clamped edges and centrally located the circular holes. Ratios of the hole diameter to the plate length, d/1, are 0.3, 0.5 and 0.7. Elastic stresses along the plate edges and the hole edges show reasonable agreement with the results from finite element analysis except corners of the plates. For elastic initial buckling load, comparison of test with analysis shows excellent agreement. Experimental ultimate loads of the plates with the ratio d/1=0, 0.3, 0.5 and 0.7 are 5.60, 6.96, 6.67, and 6.45 times of the initial buckling load, respectively.

The retention profile for ferromagnetic magnetite particles is observed directly in three kinds of parallel stream type HGMS filters which are different in the arrangement of magnetic wires. At the same time, the recovery is measured as a function of time. The filter which shows the best performance is made from the wires with a minimum separation of 0.5 mm and the spacer of a minimum thickness of 0.3 mm. As soon as the retention front reaches a filter element outlet in the filter, the recovery decreases abruptly from a value of 100%. But the breakthrough time is constant at a magnetic field strength of 3 kOe and above.

This paper proposes a new model which describes a radiative impulse electromagnetic noise distribution resulting from a digital electronic apparatus. An electronic apparatus is supposed to be composed of multiple cavities and the impulse noise is replaced by a flux of corpuscules diffused and scattered by these cavities. A subject of this research is to know how much the discrepancy between a result from this model and the real impulse noise distribution is. Preliminary results of the model verification experiment are shown.