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释义 | CCDCCDCCDCCDCCDCCDAbbrev. for charge-coupled device. A light-sensitive electronic detector, invented 1970, now widely used in ground- and space-based astronomy for imaging, photometry, spectroscopy, astrometry, etc. CCDs are normally sensitive over a wide range of wavelengths from blue light to near-infrared; developments have extended the range further into the IR (see infrared detectors), and into the ultraviolet and X-ray regions (to energies up to about 6 keV). A CCD is small (typically several square centimeters) compared with a photographic plate, and therefore covers a relatively small field of view. It also has a lower resolution than a fine-grained photographic emulsion. It does, however, have a much higher quantum efficiency – i.e. is a much more efficient detector – than emulsion; exposure times are therefore relatively much shorter. CCDs are thus well suited to the imaging of faint objects. They also have a linear response over a wide range of illumination, and in a properly designed and operating CCD system, the response is very stable over long timescales.Astronomical CCDs are fabricated as a two-dimensional array of tiny pixels (picture elements) on a thin wafer of semiconductor, usually silicon; there may be up to several thousand rows and columns of pixels. When light or other radiation is directed onto this array, each pixel responds to the photons falling on it by producing electrons. Electric charge thus accumulates in each pixel in proportion to the amount of incident radiation. After an exposure, these packets of charge are shifted out of the array and the accumulated charge in each pixel is measured, row by row. The values are digitized and stored in a computer, and may be used to form an image on a computer screen or may be further manipulated or analyzed. There is a direct relationship between the intensity of the recorded image and the original exposure, hence the linear response. Noise is, however, introduced as the charges are moved out of the CCD, amplified, digitized, and stored in the computer, thus placing a lower limit on the signal that can be accurately recorded; this readout noise can be reduced by cooling the CCD. CCDCCDCCD(1) (Charge-Coupled Device) See CCD sensor.(2) (Consumer Computing Device) An earlier term for a low-cost consumer-oriented computing product such as a PDA or Internet appliance. CCDRUNX2A gene on chromosome 6p21 that encodes a nuclear protein member of the RUNX family of transcription factors with a Runt DNA-binding domain. RUNX2 is essential for osteoblastic differentiation and skeletal morphogenesis, and acts as a scaffold for nucleic acids and regulatory factors involved in skeletal gene expression.Molecular pathology RUNX2 mutations cause cleidocranial dysplasia, a bone development disorder. CCDTelemedicine A semiconducting device–charge-coupled device in a solid-state camera or scanner which contains photosensitive (optical) cells; each pixel of an image requires a cell–the more CCDs in a scanner, the higher an image's resolution. See CCD camera.device(di-vis') [Fr. devis, contrivance]![]() abduction deviceadaptive deviceAssistive technology.adaptive seating deviceAbbreviation: ASDassistive technology deviceAssistive technology.augmentative device![]() bag mask devicebelay devicebiventricular assist deviceAbbreviation: BiVADcardiac rhythm management deviceAbbreviation: CRMDcervical immobilization deviceAbbreviation: CIDcharge-coupled deviceAbbreviation: CCDclitoral vacuum deviceelectronic infusion deviceAbbreviation: EIDesophageal intubation detector devicePatient careIf aspiration is difficult or stomach contents are withdrawn, or both, the endotracheal (ET) tube may have been placed in the esophagus and needs to be removed and reinserted. If aspiration is easy and free of stomach contents, it is probable that the ET tube is located in the trachea; the rescuer should then confirm tube placement by other techniques, e.g., a combination of auscultation, x-ray, and pulse oximetry. femoral compression deviceflow-restricted oxygen-powered ventilation deviceAbbreviation: FROPVDFlutter deviceSee: Flutter devicehead immobilization devicehumanitarian use deviceHumanitarian device exemption.improvised explosive deviceAbbreviation: IEDinput deviceinspiratory impedance threshold deviceInspiratory impedance threshold valve.intrauterine contraceptive deviceAbbreviation: IUCD, IUDSee: intrauterine contraceptive device. Kendrick extrication deviceSee: Kendrick extrication deviceleft ventricular assist deviceAbbreviation: LVADlistening devicemedical devicemobility deviceneedleless deviceoxygen-conserving deviceAbbreviation: OCRoxygen-powered ventilation deviceCAUTION!During resuscitation, it is necessary to use the positive-pressure aspect of this device and manually trigger or compress the button because the patient cannot open the valve by inhaling. These devices should be fitted with an overinflation high-pressure alarm to avoid gastric distention and/or barotrauma.personal flotation deviceAbbreviation: PFDpersonal assistive mobility devicePersonal mobility device.personal mobility devicepointing deviceposition-indicating deviceAbbreviation: PIDpositive beam limiting devicepowered mobility deviceAbbreviation: PMDpressure relief deviceprosthetic terminal deviceprotective devicepubovaginal devicesequential compression deviceAbbreviation: SCD.single-use devicespine arthroplasty devicesuperconductive quantum interference deviceAbbreviation: SQUIDtelecommunication device for the deafAbbreviation: TDD![]() ![]() venous access deviceventricular assist deviceAbbreviation: VADcharge-coupled deviceAbbreviation: CCDCCD
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