Showing papers by "Mitsubishi published in 1990"

Three-dimensional structure of ribonuclease H from E. coli

Abstract: THE three-dimensional structure of RNase H from Escherichia coli was determined at 1.8 A resolution by X-ray crystallography. The enzyme was found to belong to the α + β class of structures, consisting of two distinct domains. The structure implies a possible region interacting with a DNA–RNA hybrid. The Mg2+-binding site essential for activity is located near a cluster of four acidic amino acids— one glutamic and three aspartic acid residues. These residues are completely conserved in the homology alignment of sequences of RNase H and reverse transcriptases from retro viruses and retrovirus-like entities1,2. The structural motif of β strands around the Mg2+-binding site has similarities to that in DNase I3–6.

A superplastic covalent crystal composite

Abstract: SUPERPLASTICITY is defined phenomenologically as the ability of a material to exhibit exceptionally large elongations during tensile deformation1. It is a property of some poly crystalline solids, and is well established for metals and alloys2. Superplasticity has also been observed in some ionic crystals, such as Y2O3-stabilized tetragonal ZrO2 polycrystals3,4, but has not been found previously for covalent crystals. Here we report superplastic elongation (by more than 150%) of a covalent crystal composite, Si3N4/SiC. The superplasticity is probably related to the presence of an inter-granular liquid phase. Combined with its hardness, this property suggests several useful applications for the novel material: for example, to form engine components—superplasticity will make it readily mouldable at high temperatures.

Dead beat control of three phase PWM inverter

Abstract: A novel method for microprocessor control of three-phase sinusoidal-voltage pulse-width-modulated (PWM) inverters is proposed. First, the discretized state equations of the inverter main circuit on the d-q frame are derived. An algorithm for dead beat control with a current minor loop that constrains the inverter current within the safety limit is subsequently developed. To compensate the computing time delay, a second-order prediction method and a novel discretization method using twice the time of the sampling period have been adopted. This method is especially suitable for inverters using high-speed switching devices and digital signal processors. The validity of the control system has been demonstrated by precise simulation using a hybrid computer. >

Information collecting and/or service furnishing systems by which a user can request information from a central data base using a portable personal terminal and an access terminal

Abstract: An information collecting system comprises an access terminal connectable to a data base through a network and a host computer, an IC memory card adapted for removable insertion into the access terminal, and a portable personal terminal. Requests for an item of information, from a customer, are inputted and recorded in the IC memory card using the personal terminal and the IC memory card is inserted into the access terminal. The request for information is transmitted through the access terminal to the data base and the requested information, transmitted from the data base, is stored in the IC memory card. Thereafter, the IC memory card, storing the information, is inserted into the personal terminal whereby the requested information is displayed on a display formed in the personal terminal.

Multi-layer type semiconductor device with semiconductor element layers stacked in opposite directions and manufacturing method thereof

Abstract: A multi-layer type semiconductor device is disclosed, in which a plurality of semiconductor layers are formed in vertically opposite directions. The multi-layer type semiconductor device is obtained by forming a first semiconductor layer, an insulating layer and a second semiconductor layer in the mentioned order on a main surface of a first substrate, forming a semiconductor device by using the second semiconductor layer as a base, with an exposed surface thereof directed upward, forming an insulating film on the semiconductor device, attaching a second substrate to the insulating film, thinning the first substrate to expose the first semiconductor layer, and forming a further semiconductor device by using the first semiconductor layer as a base, with an exposed surface of the first semiconductor layer directed upward. A single- chip type image forming system or sensing system may be provided by employing, as the semiconductor devices, a sensing device such as a photosensor, a pressure sensor or the like, a processing circuit for processing a signal received from the sensor, and a display device for displaying results of the processing. A large number of pads may be provided by arranging the pads on opposite surfaces of a chip.

Panorama scene analysis with conic projection

Abstract: Proposes a conic projection image sensor (COPIS) as a navigation sensor on a mobile robot. The COPIS system is a new global positioning system which is able to get omnidirectional view information from one frame of a panoramic image. Thus, camera scanning is unnecessary. The authors report the configuration of the COPIS and its application to generate an environmental map of an indoor corridor from a moving robot. An object location is calculated from the image locus of vertical edges and the distance of the robot movement. The method uses common properties to many indoor environments rather than the geometrical world model. >

Calculation of transient 3D eddy current using edge-elements

Abstract: The calculation of transient 3-D eddy current using edge elements in the modified A-method is presented. Quadratic 36-edge elements on the 20-node isoparametric elements are proposed. Specifically, the test problems of a square plate and a hollow sphere are solved with linear 12-edge and quadratic 36-edge elements, and the results are compared with the analytical solutions. The results using the two types of elements agree well with each other and with the analytical solution, demonstrating the applicability of these elements for eddy-current calculation. The spatial distributions of the current and magnetic field in elements interpolated by shape functions are approximated better by quadratic elements with fewer degrees of freedom than the linear elements. The accuracy of both types of elements is nearly the same in the test problem of a hollow sphere if the size of the quadratic elements is double that of the linear elements. >

Carbon Isotope Ratio of Feathers Reveals Feeding Behavior of Cormorants

Abstract: Methode permettant de determiner la proportion relative des aliments d'origine terrestre et d'origine marine dans le regime alimentaire du grand cormoran.L'etude est realisee pour des oiseaux de la colonie du Shinobazunoike Pond (Tokyo) qui se nourrissent a la fois dans les rivieres et dans la baie de Tokyo

Molecular cloning and characterization of a novel type of regulatory protein (GDI) for smg p25A, a ras p21-like GTP-binding protein.

Abstract: We recently purified to near homogeneity a novel type of regulatory protein for smg p25A, a ras p21-like GTP-binding protein, from bovine brain cytosol. This regulatory protein, named smg p25A GDP dissociation inhibitor (GDI), regulates the GDP-GTP exchange reaction of smg p25A by inhibiting dissociation of GDP from and subsequent binding of GTP to it. In the present studies, we isolated and sequenced the cDNA of smg p25A GDI from a bovine brain cDNA library by using an oligonucleotide probe designed from the partial amino acid sequence of purified smg p25A GDI. The cDNA has an open reading frame that encodes a protein of 447 amino acids with a calculated Mr of 50,565. This Mr is similar to those of the purified smg p25A GDI estimated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and sucrose density gradient ultracentrifugation, which are about 54,000 and 65,000, respectively. The isolated cDNA is expressed in Escherichia coli, and the encoded protein exhibits GDI activity. smg p25A GDI is hydrophilic overall, except for one hydrophobic region near the N terminus. smg p25A GDI shares low amino acid sequence homology with the Saccharomyces cerevisiae CDC25-encoded protein, which has been suggested to serve as a factor that regulates the GDP-GTP exchange reaction of the yeast RAS2-encoded protein, but not with the beta gamma subunits of GTP-binding proteins having an alpha beta gamma subunit structure, such as Gs and Gi. The smg p25A GDI mRNA was present in various tissues, including not only tissues in which smg p25A was detectable but also tissues in which it was not detectable. This fact has raised the possibility that smg p25A GDI interacts with another G protein in tissues in which smg p25A is absent.

Edible film and method of making same

Abstract: Disclosed are heat-sealable edible films comprising at least a film layer containing a water-soluble polysaccharide as the principal component, or comprising at least (a) a film layer as described above and (b) a subfilm layer containing an alkali metal salt of casein, soybean protein or a combination of soybean protein and gelatin, as the principal component. Preferably, the water-soluble polysaccharide is composed chiefly of carrageenan and the film layer additionally contains a polyhydric alcohol. These edible films are useful in sealing or packaging powdery foods, granular foods, dry solid foods, oily foods and the like.

Multiple address-space data processor with addressable register and context switching

Abstract: Two or more address spaces are provided in a data processor. One of the address spaces comprises control registers so that the control registers can be accessed using instructions having an address in the second address space. High-speed context switching can be accomplished by allotting the context-saving area to the second address space. The context can be saved in various formats specified by a context format register.

Inductive structures for semiconductor integrated circuits

Abstract: Inductive structures having low parasitic capacitances for direct integration in semiconductor integrated circuits. In one embodiment, a generally planar spiral winding is disposed on the surface of a substrate. An electrical connection to the internal end of the spiral is made through electrically conducting vias passing through the substrate. The spiral may be spaced from a substrate surface by a plurality of spaced apart electrically conductive posts having a staggered arrangement between adjacent windings of the spiral. A transformer includes two windings disposed on top of each other on a semiconductor substrate and separated by an electrically insulating film. The windings have a common central opening in which a magnetic material is disposed to improve the inductive coupling between the windings. The transformer may include two helical windings, one surrounding another, each formed with vias and electrical conductors, the inner winding being formed in and on a semiconductor substrate and the outer winding being formed on insulating films disposed on the substrate and extending through the films and substrate. A variable inductor includes inductively coupled spiral windings separated by an insulating film and a current control for controlling the current through one of the spirals and, thereby, the effective inductance of the other spiral.

Isolation and characterization of a second RNase H (RNase HII) of Escherichia coli K-12 encoded by the rnhB gene.

Abstract: An additional RNase H (EC 3.1.26.4), RNase HII, has been isolated from Escherichia coli K-12. By screening a library of E. coli DNA for clones that suppressed RNase H deficiency of an E. coli rnh mutant, a clone was obtained that produced a protein with RNase H activity. The overexpressed RNase HIII protein in E. coli was purified to near homogeneity and exhibited a strong preference for the ribonucleotide moiety of RNA-DNA hybrid as substrate. The terminal 11 amino acids were determined and were identical to those predicted from the nucleotide sequence. The rnhB gene, which encodes RNase HII, was distinct from rnhA by its map position (4.5 min on E. coli genetic map, between lpxB and dnaE) and by the lack of significant amino acid sequence similarity. The presence of a second RNase H in E. coli indicates that multiple RNase H genes per genome is a general feature of a general feature of a wide variety of organisms.

Lead frame and semiconductor device

Abstract: A lead frame includes a die pad for mounting thereon a semiconductor chip having a plurality of electrodes, a plurality of leads for electrical connection with the plurality of electrodes of the semiconductor chip, an outer frame disposed on the periphery of the die pad for supporting the die pad and the plurality of leads, and a resin guide portion extending to the vicinity of the die pad from the outer frame for guiding molten resin over and under the semiconductor chip during resin packaging A semiconductor device manufacturing method includes mounting a semiconductor chip having electrodes on a substrate having a resin guiding portion for guiding a resin over and under the semiconductor chip during resin packaging; electrically connecting leads on the substrate to the electrodes; positioning the semiconductor chip and the substrate between a pair of mold halves injecting a molten resin into the mold to fill the cavity; and solidifying the resin

A novel form of filamentous graphite

Abstract: CARBONACEOUS materials exist in many forms, with structures varying in the degree of structural order from diamond and hexagonal graphite to the less-ordered chars, soots and coals. Traditionally, graphite is produced from the less-ordered forms of carbon by exposing them to severe conditions of high temperature and pressure. Recently, there has been much interest in preparing highly ordered phases under relatively benign conditions. For example, diamond has been synthesized at low pressures1,2, and carbon deposition on transition-metal catalysts has been shown to produce highly graphitic phases in a variety of morphologies3,4. Here we show that disproportionation of carbon monoxide (2CO →C+CO2) catalysed by small iron-containing particles gives rise to a remarkably continuous stacking of fine graphitic layers on flat surfaces of the particles, producing carbon filaments with a ribbon-like morphology. Transmission electron microscopy reveals that stacking of the layers is not only very ordered but also unusual in being orientated perpendicular to the ribbon surface. These filaments may provide unique opportunities for studies of surface adsorption, catalysis and intercalation.

High frequency link DC/AC converter with PWM cycloconverter

Abstract: A high-frequency link DC/AC converter developed for flexible, compact, and high-efficiency uninterruptible power supply (UPS) systems is discussed. The DC/AC converter consists of a 50% duty ratio rectangular voltage output inverter, a high-frequency transformer, a pulse-width modulation (PWM) cycloconverter, and an LC filter. For this converter, a three-phase output DC/AC converter can be easily realized with only one inverter and one three-phase cycloconverter. Conversion efficiency is inherently high because the inverter can utilize zero-current switching to minimize the switching loss. Output waveform control is improved because the dead time in the cycloconverter PWM can be eliminated. The main circuit configuration, the PWM method of the cycloconverter used to obtain a sinusoidal output voltage and the switching method of the inverter are described. The experimental results of a 1 kVA DC/AC converter using a high-frequency link of 20 kHz in both single-phase and three-phase output are discussed. >

Individual identification recognition system

Abstract: An individual identification recognition system for judging whether a card possessor is an authorized card user. The system includes a card storing a fingerprint of the authorized card user, a card reader into which the card is inserted, and which reads the fingerprint of the card possessor and a judging means for judging whether a card possessor is an authorized card user based upon the result of a comparison of the fingerprint of the card possessor taken in by the card reader with the fingerprint registered in the card, which judging means can be provided in the card or the card reader.

Paracoccus aminophilus sp. nov. and Paracoccus aminovorans sp. nov., Which Utilize N,N-Dimethylformamide

Abstract: Two methylamine- and N,N-dimethylformamide-utilizing Paracoccus spp. are described. These bacteria are gram-negative, nonsporeforming, nonmotile, coccoid or short rod-shaped organisms. Their DNA base composition is 62 to 68 mol% G+C. Their cellular fatty acids include large amounts of C18:1 acid. Their major hydroxy acids are 3-OH C10:0 and 3-OH C14:0 acids. The major ubiquinone is Q-10. These bacteria are distinguished from Paracoccus denitrificans and Paracoccus alcaliphilus by physiological characteristics and by DNA-DNA homology. Paracoccus aminophilus sp. nov. and Paracoccus aminovorans sp. nov. are proposed. The type strain of P. aminophilus is DM-15 (= JCM 7686), and the type strain of P. aminovorans is DM-82 (= JCM 7685). Paracoccus halodenitrificans is distinguished from other Paracoccus species on the basis of cellular fatty acid composition, hydroxy fatty acid composition, and DNA-DNA homology. It may not be a valid member of the genus Paracoccus.

Ring rolling process simulation by the three dimensional finite element method

Abstract: The finite element code “RING” was developed for the analysis of ring rolling. A special feature of the program is the updating procedure in three-dimensional deformation. A spatially fixed mesh system including deforming region of the workpiece is constructed based on the shape changes of the ring at each time step. Several simulations are performed with the program “RING”, and the results are compared with experimental data found in the literature. Good agreement between the simulation results and experiments was obtained in terms of geometrical changes of rings in plain ring rolling and T-shaped profiled ring rolling.

Integration of heterologous genes into the chromosome of Saccharomyces cerevisiae using a delta sequence of yeast retrotransposon Ty.

Abstract: Distribution of a delta (δ) sequence of the Ty element on a chromosome of the yeast Saccharomyces cerevisiae was analysed by pulsed-field gel electrophoresis. More than 100 copies of the δ sequence were non-randomly distributed on the chromosome. Using the δ sequence as a recombination site, mouse α-amylase and human β-endorphin genes were introduced into the chromosomal DNA. The integration occurred on a particular chromosome in each case and the copy number was estimated as three to five. It was also found that single- or multi-copy integration occured at a single or multiple sites on the particular chromosome. The integrants secreted α-amylase and β-endorphin by three-to fivefold compared with single-copy integrants. This type of integration was mitotically stable over a period of 50 generations under non-selective conditions.

Catheter with body temperature glass transition region

Abstract: A catheter consists of a torque transmitting portion which has rigidity sufficient for torque transmission and a flexible portion made of a material having a glass transition temperature for giving rigidity before insertion and flexibility after insertion. The torque transmitting portion maintains torque transmitting ability before, during and after insertion. The flexible portion maintains appropriate rigidity before and during insertion, which enables easy insertion, and gains flexibility after insertion by the body heat, which avoids hurting of the vulnerable insertion walls. Further, the torque transmitting portion may have a structure wherein a reinforcement of a coil or a braid of linear metal wires, specifically flat rectangular wires, is attached thereto to afford torque transmitting ability. Catheters having various functions and structures can be easily manufactured by extrusion-molding, or the like.

Pulse welding apparatus

Abstract: A pulse welding apparatus such as a pulse arc welding apparatus or a short-circuiting arc welding apparatus utilizing pulse discharge, wherein there is provided a pulse current waveform control circuit which feeds a desired pulse arc current to the arc welding power source that supplies pulse arc current to the welding load unit, the circuit being so designed as to effect optimum welding without adjusting or changing the circuit components. Even under various welding conditions or environments, furthermore, it is allowed to prevent defective welding during the arc welding caused by the magnetic blow phenomenon and to prevent defective welding such as undercut or sputtering caused by disturbances in the welding torch. The pulse current waveform control circuit is realized as a microcomputerized digital circuit, and the pulse arc current is controlled by the control operation of a program, in order to realize a desired current control by changing the program but without changing the circuit. By utilizing the memory, furthermore, the optimum welding current waveform parameter or a desired arc length signal is learned during the first welding, and the arc length feedback control or the current waveform control is effected during the second welding using a program prepared with the thus learned welding current waveform parameter or the desired arc length signal as a reference. Thus, the molten mass is prevented from being erroneously removed by the magnetic blow phenomenon, and a change in the arc length is suppressed that is caused by disturbance in the welding torch, contributing to improving the welding quality under various welding environments.

Multi-layered interconnection structure for a semiconductor device

Abstract: An interconnection layer of a semiconductor device according to the present invention has in a contact portion with a conductor layer a multi-layered structure formed from the bottom, of a refractory metal silicide layer, a first refractory metal nitride layer, and a second refractory metal nitride layer. Titanium or tungsten is used as a refractory metal. The second refractory metal nitride is formed by thermally nitriding the refractory metal layer. The second refractory metal nitride layer formed by the thermal process has a close packed crystal structure and has an excellent barrier characteristic.

Portable secure semiconductor memory device

Abstract: A portable semiconductor memory device for interfacing with and exchanging information with an external terminal, said portable device having a security function for controlling access to a main memory. The main memory is adapted to exchange data with the external terminal by means of an interface bus which includes data lines, address lines and control lines. Access controls means in the portable unit is utilized to control access to the main memory. The unit also has a security memory comprising two sections. One section stores enciphered data which is read out to the external terminal, deciphered and returned to the unit as the first element used in a comparison. The second section of the security memory stores internal identification information. The two elements of identification information are provided to a comparator means which enables access to the main memory via the interface bus after a match is detected.

Plural-coil non-contact ic card having pot cores and shielding walls

Abstract: In a non-contact IC card based on an electromagnetic induction system, N small thin-film coils formed by thin-film technology are arranged to perform N-bit parallel data transfer at an increased data transfer rate. Each thin-film coil may be constructed with a pot core to solve a problem relating to errors in positioning the card relative to a terminal unit and thereby improving the reliability of data transfer. Shielding walls may be provided between the adjacent thin-film coils to prevent interference therebetween. The N thin-film coils are integrally formed as a thin-film coil module.