Abstract: A semiconductor light receiving element comprises: a substrate, a semiconductor layer of a first conductivity type formed on the substrate, a non-doped semiconductor light absorbing layer formed on the semiconductor layer of the first conductivity type, a semiconductor layer of a second conductivity type formed on the non-doped semiconductor light absorbing layer, and an electro-conductive layer formed on the semiconductor layer of the second conductivity type. A plurality of openings, periodically arrayed, are formed in a laminated body composed of the electro-conductive layer, the semiconductor layer of the second conductivity type, and the non-doped semiconductor light absorbing layer. The widths of the openings are less than or equal to the wavelength of incident light, and the openings pass through the electro-conductive layer and the semiconductor layer of the second conductivity type to reach the non-doped semiconductor light absorbing layer.

Abstract: Intended is to provide a device structure, which makes the light receiving sensitivity and the high speediness of a photodiode compatible. Also provided is a Schottky barrier type photodiode having a conductive layer formed on the surface of a semiconductor layer. The photodiode is so constituted that a light can be incident on the back side of the semiconductor layer, and that a periodic structure, in which a light incident from the back side of the semiconductor layer causes a surface plasmon resonance, is made around the Schottky junction of the photodiode.

Abstract: In a waveguide path coupling-type photodiode, a semiconductor light absorbing layer and an optical waveguide path core are adjacently arranged. An electrode formed of at least one layer is installed in a boundary part of the semiconductor light absorbing layer and the optical waveguide path core. The electrodes are arranged at an interval of (1/100)? to ? [?: wavelength of light transmitted through optical waveguide path core]. At least a part of the electrodes is embedded in the semiconductor light absorbing layer. Embedding depth from a surface of the semiconductor light absorbing layer is a value not more than ?/(2ns) [ns: refractive index of semiconductor light absorbing layer]. At least one layer of the electrode is constituted of a material which can surface plasmon-induced.

Abstract: Disclosed are a novel hydantoin racemase and a process for producing an optically active N-carbamylamino acid or an optically active amino acid using the hydantoin racemase. A novel hydantoin racemase isolated and purified from Bacillus sp. Strain KNK519HR; a gene encoding the hydantoin racemase; a recombinant plasmid having the gene introduced therein; a transformant having the hydantoin racemase gene introduced therein; and a process for producing an optically active N-carbamylamino acid or an optically active amino acid characterized in that a 5-substituted hydantoin compound is treated in the presence of hydantoinase and N-carbamylamino acid amidohydrolase as well as the hydantoin racemase.

Abstract: A photodiode includes: an upper spacer layer including a semiconductor transparent to incident light; a metal periodic structure provided on the upper spacer layer and arranged to induce surface plasmon, the metal periodic structure including first and second electrodes including portions arranged alternately on the upper spacer layer; a light absorption layer formed under the upper spacer layer and including a semiconductor having a refractive index higher than that of the upper spacer layer; and a lower spacer layer formed under the light absorption layer and having a refractive index smaller than that of the light absorption layer. Each of the first and second electrodes forms a Schottky barrier junction with the upper spacer layer.

Abstract: A light receiving circuit (114) includes a light inputting circuit (113) which converts one-system optical signal to be outputted from an optical transmission path (101) to an electrical signal and inverts a potential of the electrical signal each time the optical signal is detected, and a buffer circuit (110) which amplifies the electrical signal converted by the light inputting circuit and outputs the same. According to such configuration, since one-system optical signal may be inputted to the light receiving circuit, a system circuit configuration can be avoided to be complicated.

Abstract: Disclosed are a novel hydantoin racemase and a process for producing an optically active N-carbamylamino acid or an optically active amino acid using the hydantoin racemase. A novel hydantoin racemase isolated and purified from Bacillus sp. Strain KNK519HR; a gene encoding the hydantoin racemase; a recombinant plasmid having the gene introduced therein; a transformant having the hydantoin racemase gene introduced therein; and a process for producing an optically active N-carbamylamino acid or an optically active amino acid characterized in that a 5-substituted hydantoin compound is treated in the presence of hydantoinase and N-carbamylamino acid amidohydrolase as well as the hydantoin racemase.

Abstract: A video game apparatus includes a CPU, and the CPU executes a game process of an RPG stored in an optical disk. The CPU refers to state data of a player possessing item (specific item) stored in a main memory, and when the state data of the specific item shows a predetermined state, an actionable time-period of a player character (leading character) in a game world is extended.

Abstract: A game apparatus includes a CPU, and in the game apparatus, letters are displayed as visual support for a sound generated by a message generating object. When a game message is displayed, a distance between the message generating object and a player object is calculated. Then, a form of a texture of the letters to be pasted on a billboard is changed depending upon the calculated distance. The form to be changed is, for example, transparency and a size of the texture of the letters. Thus, a game image in which the form of the letters is changed depending upon the distance between the player object and the message generating object is displayed.

Abstract: A gene of decaprenyl diphosphate synthase, which is the key gene participating in the biosynthesis of coenzyme Q10 was isolated from a bacterium belonging to the family Rhizobiaceae. By transferring this gene into a microorganism such as Escherichia coli and expressing therein, coenzyme Q10 can be effectively produced.

Abstract: Provided by the present invention is a II-VI compound semiconductor based light emitting device which is suppressed in the propagation velocity of crystal defects at the time of current application, has a prolonged lifetime and can be readily mass produced. The device has a recombination region and non-recombination region of carriers which have been separated spatially each other in the plane of the active layer.

Abstract: The object of the present invention is to provide a variable wavelength semiconductor laser which is large in ontinuous variable wavelength width, simple and convenient in structure, easy to produce, monolithic and small in size, and easy to handle. The variable wavelength semiconductor laser includes an optical gain region formed from two-dimensional or three-dimensional carrier confinement structures having sizes approximately of a thermal de Broglie wavelength whose size dispersion is controlled so that a gain spectrum covers a required variable wavelength region for generating and amplifying light when current is injected, a light absorption control region having a light absorption coefficient which varies depending upon a current injection amount, an optical resonator including the optical gain region and the light absorption control region, and control means for controlling current amounts or voltage values to be injected to the optical gain region and the light absorption control region.

Abstract: Disclosed is a silver halide photographic photosensitive material comprising a support and, provided thereon, at least one hydrophilic colloid layer including a photosensitive layer wherein the photosensitive layer comprises monodispersed silver halide grains having an average grain size of 0.2 micron or less and comprising at least 90 mol % of silver chloride, the photosensitive layer or a hydrophilic colloid layer provided on the same side of the support as the side on which the photosensitive layer is provided contains a hydrazine derivative, a hydrophilic colloid layer provided above the photosensitive layer contains a water-dispersible fine particle polymer, the photosensitive layer contains substantially no water-dispersible fine particle polymer, and amount of the water-dispersible fine particle polymer contained in the hydrophilic colloid layer is 1 g/m.sup.2 or less and is 5% by weight or more based on the weight of gelatin contained in the hydrophilic colloid layer.

Abstract: An optical modulator for varying intensity, frequency, phase and other information associated with input light in response to a voltage which is applied thereto from outside is disclosed. The modulator comprises a semiconductor substrate, at least one semiconductor ultrathin layer which is thinner than an order of electron mean free path, and electrodes capable of applying an electric field to said ultrathin layer in a perpendicular direction to the layers. The band gap of narrow band gap layers in the ultrathin layer is spatially varied with respect to the perpendicular direction to the layers. The band gap of the narrow band gap layers is monotonously varied in the perpendicular direction to the layers. The ultrathin layer is interposed between a p-type semiconductor and an n-type semiconductor with respect to the perpendicular direction to the layers, a band gap of semiconductor layers in the ultrathin layer and having a narrow band gap being sequentially narrowed toward the p-type semiconductor layer.