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Dark Energy Survey
The Dark Energy Survey (DES) is an astronomical survey designed to constrain the properties of dark energy. It uses images taken in the near-ultraviolet, visible, and near-infrared to measure the expansion of the universe using Type Ia supernovae, baryon acoustic oscillations, the number of galaxy clusters, and weak gravitational lensing. The collaboration is composed of research institutions and universities from the United States,DES Collaboration Page DES Collaborators. Australia, Brazil,DES-Brazil , DES-Brazil Consortium. the United Kingdom, Germany, Spain, and Switzerland. The collaboration is divided into several scientific working groups. The director of DES is [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Astronomical Survey
An astronomical survey is a general map or image of a region of the sky (or of the whole sky) that lacks a specific observational target. Alternatively, an astronomical survey may comprise a set of images, spectra, or other observations of objects that share a common type or feature. Surveys are often restricted to one band of the electromagnetic spectrum due to instrumental limitations, although multiwavelength surveys can be made by using multiple detectors, each sensitive to a different bandwidth. Surveys have generally been performed as part of the production of an astronomical catalog. They may also search for transient astronomical events. They often use wide-field astrographs. Scientific value Sky surveys, unlike targeted observation of a specific object, allow astronomers to catalog celestial objects and perform statistical analyses on them without complex corrections for selection effects. In some cases, an astronomer interested in a particular object will find ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Liquid Nitrogen
Liquid nitrogen—LN2—is nitrogen in a liquid state at low temperature. Liquid nitrogen has a boiling point of about . It is produced industrially by fractional distillation of liquid air. It is a colorless, low viscosity liquid that is widely used as a coolant. Physical properties The diatomic character of the N2 molecule is retained after liquefaction. The weak van der Waals interaction between the N2 molecules results in little interatomic interaction, manifested in its very low boiling point. The temperature of liquid nitrogen can readily be reduced to its freezing point by placing it in a vacuum chamber pumped by a vacuum pump. Liquid nitrogen's efficiency as a coolant is limited by the fact that it boils immediately on contact with a warmer object, enveloping the object in an insulating layer of nitrogen gas bubbles. This effect, known as the Leidenfrost effect, occurs when any liquid comes in contact with a surface which is significantly hotter than its boil ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
South Pole Telescope
The South Pole Telescope (SPT) is a diameter telescope located at the Amundsen–Scott South Pole Station, Antarctica. The telescope is designed for observations in the microwave, millimeter-wave, and submillimeter-wave regions of the electromagnetic spectrum, with the particular design goal of measuring the faint, diffuse emission from the cosmic microwave background (CMB). The first major survey with the SPT—designed to find distant, massive, clusters of galaxies through their interaction with the CMB, with the goal of constraining the dark energy equation of state—was completed in October 2011. In early 2012, a new camera (SPTpol) was installed on the SPT with even greater sensitivity and the capability to measure the polarization of incoming light. This camera operated from 2012–2016 and was used to make unprecedentedly deep high-resolution maps of hundreds of square degrees of the Southern sky. In 2017, the third-generation camera SPT-3G was installed on the tele ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Photoelectric Effect
The photoelectric effect is the emission of electrons when electromagnetic radiation, such as light, hits a material. Electrons emitted in this manner are called photoelectrons. The phenomenon is studied in condensed matter physics, and solid state and quantum chemistry to draw inferences about the properties of atoms, molecules and solids. The effect has found use in electronic devices specialized for light detection and precisely timed electron emission. The experimental results disagree with classical electromagnetism, which predicts that continuous light waves transfer energy to electrons, which would then be emitted when they accumulate enough energy. An alteration in the intensity of light would theoretically change the kinetic energy of the emitted electrons, with sufficiently dim light resulting in a delayed emission. The experimental results instead show that electrons are dislodged only when the light exceeds a certain frequency—regardless of the light's intensity o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
IPhone 4
The iPhone 4 is a smartphone that was designed and marketed by Apple Inc. It is the fourth generation of the iPhone lineup, succeeding the iPhone 3GS and preceding the 4S. Following a number of notable leaks, the iPhone 4 was first unveiled on June 7, 2010, at Apple's Worldwide Developers Conference in San Francisco, and was released on June 24, 2010, in the United States, United Kingdom, France, Germany, and Japan. The iPhone 4 introduced a new hardware design to the iPhone family, which Apple's CEO Steve Jobs touted as the thinnest smartphone in the world at the time; it consisted of a stainless steel frame which doubled as an antenna, with internal components situated between two panels of aluminosilicate glass. The iPhone 4 introduced Apple's new high-resolution " Retina Display" (with a pixel density of 326 pixels per inch), while maintaining the same physical size and aspect ratio as its precursors, Apple's A4 system-on-chip, along with iOS 4—which notably intro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
OmniVision Technologies
OmniVision Technologies Inc. is an American subsidiary of Chinese semiconductor device and mixed-signal integrated circuit design house Will Semiconductor. The company designs and develops digital imaging products for use in mobile phones, notebooks, netbooks and webcams, security and surveillance cameras, entertainment, automotive and medical imaging systems. Headquartered in Santa Clara, California, OmniVision Technologies has offices in the US, Western Europe and Asia. In 2016, OmniVision was acquired by a consortium of Chinese investors consisting of Hua Capital Management Co., Ltd., CITIC Capital Holdings Limited and Goldstone Investment Co., Ltd. History OmniVision was founded in 1995 by Aucera Technology (TAIWAN:奧斯來科技). Some company milestones: * 1999: First application-specific IC (ASIC) * 2000: IPO * 2005: Acquired CDM-Optics, a company founded to commercialize wavefront coding. * 2010: Acquires Aurora Systems and adds LCOS to its product line * 2011 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lawrence Berkeley National Laboratory
Lawrence Berkeley National Laboratory (LBNL), commonly referred to as the Berkeley Lab, is a United States national laboratory that is owned by, and conducts scientific research on behalf of, the United States Department of Energy. Located in the hills of Berkeley, California, the lab overlooks the campus of the University of California, Berkeley, and is managed by the University of California system. History 1931–1941 The laboratory was founded on August 26, 1931, by Ernest Lawrence, as the Radiation Laboratory of the University of California, Berkeley, associated with the Physics Department. It centered physics research around his new instrument, the cyclotron, a type of particle accelerator for which he was awarded the Nobel Prize in Physics in 1939. Throughout the 1930s, Lawrence pushed to create larger and larger machines for physics research, courting private philanthropists for funding. He was the first to develop a large team to build big projects to make discove ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dalsa
Teledyne DALSA (formerly DALSA Corporation) is a Canadian company specializing in the design and manufacture of specialized electronic imaging components (image sensors, cameras, frame grabbers, imaging software) as well as specialized semiconductor fabrication (MEMS, high voltage ASICs). Teledyne DALSA is part of the Teledyne Imaging group, the leading-edge imaging companies aligned under the Teledyne umbrella. History The company was founded in Waterloo, Ontario, Canada in 1980 by imaging pioneer Savvas Chamberlain, a former professor in electrical engineering at the University of Waterloo. The company was capitalised in November 1984 and was publicly listed on the Toronto Stock Exchange in May 1996. The company originally concentrated in developing and generating charge coupled device (CCD) image sensor technology. It has since grown into an industry leader in semiconductor technology, employing approximately 1000 individuals worldwide and earning revenues of more than $200 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Back-illuminated Sensor
Comparison of simplified back-illuminated and front-illuminated pixel cross-sections A back-illuminated sensor, also known as backside illumination (BI) sensor, is a type of digital image sensor that uses a novel arrangement of the imaging elements to increase the amount of light captured and thereby improve low-light performance. The technique was used for some time in specialized roles like low-light security cameras and astronomy sensors, but was complex to build and required further refinement to become widely used. Sony was the first to reduce these problems and their costs sufficiently to introduce a 5-megapixel 1.75 µm BI CMOS sensor at general consumer prices in 2009.''Sony'', 2009 BI sensors from OmniVision Technologies have since been used in consumer electronics from other manufacturers as in the HTC EVO 4G Android smartphone, and as a major selling point for the camera in Apple's iPhone 4.''Apple'', 2010 Description A traditional, front-illuminated digital ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dark Energy Camera's 1 Millionth Exposure
Darkness, the direct opposite of lightness, is defined as a lack of illumination, an absence of visible light, or a surface that absorbs light, such as black or brown. Human vision is unable to distinguish colors in conditions of very low luminance. This is because the hue sensitive photoreceptor cells on the retina are inactive when light levels are insufficient, in the range of visual perception referred to as scotopic vision. The emotional response to darkness has generated metaphorical usages of the term in many cultures, often used to describe an unhappy or foreboding feeling. Referring to a time of day, complete darkness occurs when the Sun is more than 18° below the horizon, without the effects of twilight on the night sky. Scientific Perception The perception of darkness differs from the mere absence of light due to the effects of after images on perception. In perceiving, the eye is active, and the part of the retina that is unstimulated produces a compleme ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
DECam Iphone Insert
The Dark Energy Survey (DES) is an astronomical survey designed to constrain the properties of dark energy. It uses images taken in the near-ultraviolet, visible, and near-infrared to measure the expansion of the universe using Type Ia supernovae, baryon acoustic oscillations, the number of galaxy clusters, and weak gravitational lensing. The collaboration is composed of research institutions and universities from the United States,DES Collaboration Page DES Collaborators. Australia, Brazil,DES-Brazil , DES-Brazil Consortium. the United Kingdom, Germany, Spain, and Switzerland. The collaboration is divided into several scientific working groups. The director of DES is [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Quantum Efficiency
The term quantum efficiency (QE) may apply to incident photon to converted electron (IPCE) ratio of a photosensitive device, or it may refer to the TMR effect of a Magnetic Tunnel Junction. This article deals with the term as a measurement of a device's electrical sensitivity to light. In a charge-coupled device (CCD) or other photodetector, it is the ratio between the number of charge carriers collected at either terminal and the number of photons hitting the device's photoreactive surface. As a ratio, QE is dimensionless, but it is closely related to the responsivity, which is expressed in amps per watt. Since the energy of a photon is inversely proportional to its wavelength, QE is often measured over a range of different wavelengths to characterize a device's efficiency at each photon energy level. For typical semiconductor photodetectors, QE drops to zero for photons whose energy is below the band gap. A photographic film typically has a QE of much less than 10%, whi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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