摘要:
Provided is a small-size and highly stable oscillator which can easily correct a frequency shift caused by a temperature fluctuation. The oscillator includes: an overtone crystal unit of three or higher dimension; an oscillation circuit which is connected to the crystal unit and outputs an oscillation frequency; a divider which divides the oscillation frequency and outputs the divided frequencies to a system device processing unit; a temperature sensor which detects a temperature around the crystal unit; and a memory which stores information for correcting a frequency shift of an oscillation frequency according to the temperature characteristic of the crystal unit (a coefficient of an equation for calculating a correction amount of a frequency shift or the frequency shift corresponding to the temperature) and provides information to be used for correcting the frequency shift to the system device processing unit.
摘要:
There is provided a calibration apparatus used for a photon counting type of radiation detector. In this apparatus, a radiation condition of a radiation is set such that particles of the radiation (X-rays) which are incident on a plurality of detection modules are piled up over each other at a probability which is equal to or less than a predetermined value. Under the setting of this radiation condition, detection sensitivities for the radiation are made uniform among the plurality of detection modules. Using this uniformed result, the detection sensitivities for the radiation are further made uniform every channel of each of the pixels formed by circuit groups including the plurality of detection modules, discrimination circuits and data calculation circuits and every discrimination circuit in each channel.
摘要:
A panoramic imaging apparatus is provided, which is able to freely display a focus-optimized internal structural image of the tooth row depending on a position using image data acquired by only one-time X-ray panoramic imaging from an arbitrary section along a patient's tooth row.The panoramic imaging apparatus comprise an X-ray source (31) and a detector (32) outputting a digital electrical signal depending on an incident X-ray at a constant frame rate. This apparatus further comprises means (24) for moving a pair of the X-ray source and the detector around an object in a state where the X-ray source and the detector are opposed to each other with the object located therebetween, means (54) for sequentially storing, as frame data, the electrical signal outputted by the detector, means (56) for producing a panoramic image of a desired section of the object based on the frame data, and means (56, 57, 58) for producing a partial sectional image using the frame data, the partial sectional image being an image of a partial region specified on the panoramic image and being focused depending on a desired position in an imaging space.
摘要:
A radiation imaging apparatus is provided. The apparatus has moving means moving a pair of an X-ray tube and a detector relatively to an object. The apparatus further has means which acquire digital frame data outputted from the detector. The frame data are acquired from the same portion being imaged of the same object at different time points. The apparatus has means which use the frame data to produce a plurality of three-dimensional optimally focused images at the respective time points, an actual position and shape of the portion being imaged being reflected in the images, and means which estimate changes of the plural three-dimensional optimally focused images.
摘要:
A surface mount crystal oscillator comprises a crystal blank, an IC chip having an oscillation circuit integrated thereon, and a hermetic package for accommodating the crystal blank and IC chip therein. The hermetic package comprises a substantially rectangular ceramic substrate formed with a metal film which makes a round on one main surface thereof, and a concave metal cover having an open end face bonded to the metal film. The IC chip is secured to the one main surface of the ceramic substrate through ultrasonic thermo-compression bonding using bumps, the crystal blank is disposed above the IC chip, and the ceramic substrate has the one main surface formed as a flat surface.
摘要:
A hydraulic composition is provided. This composition exhibits an improved workability in its coating with a trowel, and accordingly, an improved working efficiency with no adverse effects on its physical properties. The hydraulic composition comprises at least one surfactant selected from anionic surfactants having foaming ability (group A), at least one surfactant selected from surfactants which are nonionic antifoaming agents (group B), and a water-soluble cellulose ether. The surfactants of group A and group B are respectively added at 0.000005 to 0.004% by weight (solid content) in relation to the powder ingredients in the hydraulic composition, and the water-soluble cellulose ether is added at 0.02 to 1.2% by weight of the hydraulic composition.
摘要:
Hydraulic compositions comprising a setting accelerator, a water-soluble cellulose ether having a degree of alkyl substitution of 1.6 to 2.5 which is a water-soluble alkyl cellulose or a water-soluble hydroxyalkyl alkyl cellulose, and water are useful as self-leveling compositions having an excellent self-leveling capability, a minimal change with time of fluidity, and a short setting time, or as cement mortar compositions having a long open time and a short setting time.
摘要:
An additive for a cement composition comprising: (A) a polycarboxylic acid based copolymer and/or a salt thereof; (B) water-soluble cellulose ether; and (C) a defoaming agent.
摘要:
An additive for a cement composition comprising: (A) a polycarboxylic acid based copolymer and/or a salt thereof; (B) water-soluble cellulose ether; and (C) a defoaming agent.
摘要:
A digital temperature-compensated oscillator comprises a crystal oscillator, a first memory previously storing digital temperature compensation data obtained by previously measuring the relation between the ambient temperatures and the frequency deviations of the crystal oscillator, a second memory for storing frequency offset amounts of the oscillation frequency of the crystal oscillator, a temperature sensor for outputting analog detection data relating to the ambient temperature, an A/D converter for converting the analog detection data to digital detection data, a readout circuit for reading out temperature compensation data corresponding to the digital detection data and stored in the first memory according to the digital detection data and reading out the frequency offset amount stored in the second memory according to the digital detection data, an operation circuit for effecting the following calculation by use of the readout temperature compensation data and readout frequency offset amount to derive digital control voltage,V.sub.c =V.sub.co +(K.sub.00 +V.sub.co K.sub.10 +K.sub.01 T).times.(.DELTA.F+.DELTA.F.sup.2 .times.K.sub.10 /2)where K.sub.00, K.sub.01 and K.sub.10 are constants, V.sub.co is an initial value of the control voltage, T is an ambient temperature and .DELTA.F is a frequency offset amount, a D/A converter for converting the digital control voltage into an analog control voltage, and a voltage-capacitance converter for receiving the analog control voltage and generating a control signal to be supplied to the crystal oscillator according to the received analog control voltage, wherein the frequency of the crystal oscillator is controlled according to the control signal.