Abstract: A thermal print head driving system supplies a predetermined number of driving pulses to each of a plurality of heat-producing elements arranged in a line to record a single dot of desired tone. The pulse width of driving pulse is controlled in accordance with the temperature at or in the vicinity of the heat-producing elements thereby allowing to maintain the density level of desired tone at constant. In another aspect of the present invention, it is so structured that driving pulses may be applied to the heat-producing elements in a continuous manner without producing a cooling period during switching between tone levels. In a further aspect of the present invention, it is so structured that a predetermined number of driving pulses for each of predetermined number of tone levels is altered in consideration of the data in at least one of preceding recording lines, thereby allowing to carry out a high speed recording operation without causing fluctuations in predetermined tone density level.

Abstract: A thermal recording system includes a thermal print head provided with a plurality of electrical resistors arranged in the form of a single row and selectively activated when an activation pulse is supplied, a brute supply for supplying a power supply voltage to the resistors and a pulse generator for controlling the duration of the activation pulse in accordance with the level of the power supply voltage actually applied to the resistors. The pulse generator controls the pulse width of the activation pulse so as to maintain substantially constant the activation energy defined as a product of (power supply voltage actually applied).sup.2 and (pulse width of activation pulse).

Abstract: An optical switching device for switching the transmission of light waves is provided. The main feature of the present invention is the usage of a light-transmitting, crystalline material having a temperature dependent index of refraction. That is, the light transmission condition is altered by controlling the temperature of such a material. In one form of the present invention, a main waveguide and a branched waveguide are provided and light waves are switched between the main and branched waveguides by controlling the temperature of a particlar portion of the intersection region. In another form of the present invention, a pair of waveguides is oppositely arranged in an end-to-end relation with a gap therebetween, and a switching region is defined in the gap. When the switching region is heated, the waveguides are optically connected; whereas, they are optically disconnected at normal temperature condition.

Abstract: A batch-operated furnace apparatus for manufacturing powdered silicon nitride comprises a reaction furnace having a reaction chamber, an upper portion, a bottom portion and a side portion, a feed pipe placed at the upper portion of the reaction furnace for feeding starting materials in a fine or coarse particle form, an exhaust pipe placed at the upper portion of the reaction furnace for removing gasses from the reaction chamber, a gas distributor plate positioned at the bottom portion of the reaction chamber for introducing nitrogen gas into the reaction chamber so as to form a fluidized bed at the bottom portion of the reaction chamber, a heater for heating the starting materials of the fluidized bed within the reaction chamber, a discharge port formed in the gas distributor plate, a discharge pipe joined to the discharge port of the gas distributor plate, a valve seat formed at the discharge port, a discharge valve means having the valve which engages the valve seat of the discharge port, and a guide tube

Abstract: A flexible amorphous silicon solar battery comprising a metal foil as the substrate thereof, an insulating layer integrally formed on the metal foil, and at least one amorphous silicon photoelectric conversion portion formed on the insulating layer. The amorphous silicon photoelectric conversion portion thereof comprises an a-Si thin film having a potential barrier therein, an upper electrode and a lower electrode. The a-Si thin film is sandwiched between the upper and lower electrodes. The upper electrodes may be formed of a transparent conductive film. The transparent conductive film may be also in two layers composed of a relatively thin tin dioxide film and a relatively thick ITO film thereby to lower the resistance of transparent conductive film and to obtain a superior a-Si thin film having no impurity particles therein. A plurality of a-Si photoelectric conversion portions may be formed on the same substrate, and are connected in series with one another, to increase the output voltage thereof.

Abstract: Disclosed is a process for preparing silicon nitride powder, which comprises baking a powdery mixture comprising (i) 1 part by weight of silica powder, or a silica-containing substance in terms of silica, (ii) 0.4 to 4 parts by weight of carbon powder, or a substance generating carbon by baking, in terms of carbon and (iii) 0.005 to 1 part by weight of silicon nitride powder synthesized by a silica reduction method, at a temperature of from 1350.degree. to 1550.degree. C. in a non-oxidative atmosphere containing nitrogen.

Abstract: The simultaneous multi-beam optical modulation system comprises the steps of producing a dummy signal in such a manner that the sum of a plurality of signals and the dummy signal is kept constant, modulating the amplitudes of assigned carriers by the dummy signal and the plurality of the signals so as to produce a modulated output and applying the modulated output to an acoustic optical element.

Abstract: The simultaneous multi-beam optical modulation process comprises the steps of obtaining a plurality of modulated signals with the amplitude of carriers having different frequencies modulated by a plurality of signals, and driving an acoustic optical element by the modulated signals so that a light modulation is performed by the acoustic optical element. In this system, a dummy signal is produced by squaring a plurality of the signals and adding and then inverting the squared signals and a setting voltage for setting an overall deflection efficiency of the acoustic optical element, or by adding and then inverting a plurality of the signals and the setting voltage and then squaring the sum. The amplitude of an assigned carrier is modulated by the dummy signal and a modulated output is obtained. The modulated output and the modulated signals are summed up into a summed-up signal, which is then applied to the acoustic optical system. An apparatus for carrying out the process is also described.

Abstract: The simultaneous multi-beam optical modulation process comprises the steps of producing a dummy signal in such a manner that the sum of a plurality of signals and the dummy signal is kept constant, modulating the amplitudes of assigned carriers by the dummy signal and the plurality of the signals so as to produce a modulated output and applying the modulated output to an acoustic optical element. An apparatus for carrying out the process is also disclosed.

Abstract: This invention provides a method for manufacturing said sintered body, comprising preparing a starting material by adding 10 to 1,000 wt. parts of metal silicon powder to 100 wt. parts of mixed powder composed of 20 to 80 wt. % silica powder and 80 to 20 wt. % aluminium powder and mixing said powders thoroughly, further adding, if required, a refractory fine powder of alumina, silicon nitride, aluminium nitride, .beta.'-sialon, aluminium nitride polytype sialon, or silicon carbide, molding the resultant mixture into a green compact, and then sintering said green compact in a nitrogeneous nonoxidative gas atmosphere at a temperature of 1,200.degree. to 1,550.degree. C. This invention further provides a compact sintered body which will be prepared by the above mentioned method.

Abstract: A process for preparing silicon nitride powder having a high .alpha.-phase content which comprises the steps of (a) providing a blended powder material composed of silica powder and amorphous carbon powder having an oil absorption of not less than 100 ml/100g, the weight ratio of the carbon powder to the silica powder being not less than 0.5, and then (b) nitriding and burning the blended powder material by heating in at a temperature of from 1300.degree. to 1700.degree. C while feeding a nitrogen-containing, non-oxidizing gas. The product obtained by this process is suitable as a raw material for the manufacture of high-density and high-strength sintered articles of silicon nitride.