摘要:
An apparatus for recording data includes a source of digital data arranged into data words having a given number of bits and a converter that converts the data words to code words having one more bit than the given number using a group code recording format. The code words include a binary signal having first and second binary values at a given clock interval determined by a bit rate of the code words. The apparatus also includes a storage disk having a recording surface, a drive member for rotatably driving the disk, a laser having a focused beam, and a control assembly for directing the laser at the recording surface so that the beam accesses one of a plurality of concentric tracks on the recording surface. A circuit assembly provides a driving signal utilized for generating energizing pulses having a duration less than the clock interval when the binary signal has the first binary value. A pulse generator applies the energizing pulses to the laser to activate the laser responsive to the energizing pulses so that the laser is turned on and off even when the binary signal does not change value from one bit to the next. A high density optical disk including a plurality of tracks arranged in a predetermined number of zones may be utilized in conjunction the apparatus, which may be further incorporated into an optical data storage and retrieval system.
摘要:
A transportable apparatus for preventing the spreading and coming ashore of spilled oil that is easily transportable to a sea area where spilled oil is spread and that can perform the operation of preventing the spreading and coming ashore of spilled oil in the open area. The apparatus has an oil-fence-housing robot ship (10) and a pair of oil-fence-setting-up robot ships (20, 30) that are separably coupled together into an easily transportable block body. The apparatus encircles a sea area where spilled oil is spread with oil fences (40, 41) by remotely operating the robot ships (10, 20, 30) via radio signals.
摘要:
An apparatus and method for retrieving densely stored data from various types of magnetic media. A medium is scanned to provide an input signal. The input signal is conditioned through differentiation, equalization and partial integration. Positive and negative signal peak detectors are connected to the conditioned signal, and a threshold signal is generating corresponding to an average or midpoint of the measured positive and negative signal peaks. An output signal is generated by comparing the conditioned signal and the threshold signal. The DC component of the input signal is accounted for by feeding back the output signal and adjusting the threshold signal based on the duty cycle of the output signal.
摘要:
Proposed is an article of pyrolytic boron nitride such as crucibles for use at a high temperature under an extremely high vacuum as in the molecular beam epitaxy. The article can be used in the high temperature, high vacuum process without the conventional elaborate and time-consuming degassing bake-out treatment because the article is wrapped in a wrapping film having a specified low moisture permeability immediately after a preliminary degassing treatment under specified conditions before the article is wrapped under a low-moisture atmosphere in a glove box.
摘要:
A first write encoder encodes digital data in a first, high-density format. A second write encoder encodes digital data in a second, low-density (i.e., ANSI) format. A first read decoder decodes digital data from the first format. A second read decoder decodes digital data from the second format. A disk drive receives a replaceable 90 millimeter optical disk. A read/write head reads encoded data from and writes encoded data to a 90 millimeter optical disk received by the drive. In a first mode, the first write encoder is connected between a source of digital data and the read/write head, and the first read decoder is connected between the read/write head and the utilizing apparatus. In a second mode, the second write encoder is connected between the source and the read/write head, and the second read decoder is connected between the read/write head and the utilizing apparatus. Control electronics switch between the first and second modes, depending upon the format in which data is recorded on the disk received by the disk drive. An 8/9 GCR encoder and a laser pulse generator are used in the first write encoder to record data on the optical media to increase the storage capacity. Improvement in timing is accomplished with write compensation and signal equalization.
摘要:
There is disclosed a heating element 10 comprising: at least a heat-resistant base member 1; a conductive layer 3 having a heater pattern 3a formed on the heat-resistant base member; a protection layer 4 with an insulating property formed on the conductive layer; and a corrosion-resistant layer 4p having a nitrogen gas permeability of 1×10−2 cm2/sec or less or being made of a compound containing a dopant formed on the protection layer 4. There can be provided a heating element in which a corrosion-resistant layer whose nitrogen gas permeability, resistivity, or hardness are controlled is formed on a protection layer and through which the corrosive gas is difficult to be transmitted even under an environment of a high temperature and a corrosive gas and by which degradation due to corrosion of a conductive layer, particularly, a power-supply-terminal portion can be avoided and additionally which can fulfill a high function as an electrostatic chuck even when having a chuck pattern and which has a long operation life and is capable of being produced at a low cost.
摘要:
Disclosed is a crucible of pyrolytic boron nitride (PBN) for molecular beam epitaxy for melting of the source material, with which the troubles due to adhering of the molten source material in the form of drops caused on the quality of the epitaxial layer can be greatly decreased. Namely, the inner surface of the crucible is free from pits or other irregularities responsible to the adhering of the melt when the growth plane, which can be exposed by stripping of the surface layer of 0.50 mm thickness by cleavage, has a surface roughness Ra not exceeding 2.0 .mu.m and Rmax not exceeding 18 .mu.m. Such a PBN crucible can be prepared by the CVD method to deposit PBN on the surface of a graphite core of which the surface roughness Ra does not exceed 2 .mu.m.
摘要:
An improvement is proposed in the preparation of, for example, a ceramic heater consisting of a substrate plate of boron nitride, a patterned layer of pyrolytic graphite (PG) on the substrate to serve as an electric resistance element and an overcoating layer of pyrolytic boron nitride (PBN) in a process comprising the steps of depositing PG on the substrate surface, pattern-wise removing the PG layer by mechanical working to form grooves and depositing PBN all over. According to the inventive improvement, which can be obtained by forming the grooves in such a fashion that the angle between the direction of a normal line to the facet surface formed by the mechanical working and the growing direction of the substrate of boron nitride is in the range from 0.degree. to 45.degree. so that the internal stress caused in the overcoating layer, which is due to the anisotropy in the thermal expansion of boron nitride, is decreased to prevent the overcoating layer from occurrence of cracks and falling during service.
摘要:
A data generator assembly for use in retrieving stored data from an information storage medium. The data generator assembly includes a positive peak detector for receiving a preprocessed signal having a predetermined waveform including positive peaks, negative peaks, and a DC component. The positive peak detector is utilized to measure and track the positive peaks to output a positive peak signal. A negative peak detector measures and tracks the negative peaks to output a negative peak signal. The data generator assembly also includes a voltage divider for averaging the negative peak signal and the positive peak signal and generating a threshold signal representing the approximate peak-to-peak midpoint of the preprocessed signal which varies with the DC component. A comparator is provided for comparing the preprocessed signal with the threshold signal. The comparator generates an output data waveform signal indicative of the stored data on information storage medium.
摘要:
Although a workpiece can be elevated or lowered according to the invention, the workpiece is prevented from rising or falling abruptly. When the workpiece is elevated with an external force, air supplied from the side of an auxiliary air supply chamber pushes down a pressure control piston. Since a difference in pressure between the side of a piston pressure chamber and the side of an auxiliary air supply chamber is small, air is prevented from flushing from the side of the auxiliary air supply chamber into the piston pressure chamber. When the workpiece is lowered with an external force, the pressure control piston is pushed up, thereby increasing the pressure in the piston pressure chamber. At the same time, a relief valve is opened and the piston pressure chamber is exhausted. By the provision of a relief valve, excess air is not exhausted from the piston pressure chamber. The pressure control piston is prevented from rising abruptly, and the workpiece can be gradually raised or lowered.