- 行业: Printing & publishing
- Number of terms: 178089
- Number of blossaries: 0
- Company Profile:
McGraw Hill Financial, Inc. is an American publicly traded corporation headquartered in Rockefeller Center in New York City. Its primary areas of business are financial, publishing, and business services.
An instrument for visualizing and measuring differences in the phase of light transmitted through or reflected from microscopic specimens. It is closely allied to the phase-contrast microscope.
Industry:Science
An instrument for weighing. The word “balance,” derived from the Latin <i>bilanx</i> (“having two pans”), is often used interchangeably with “scale” or “scales” (Old English, meaning dishes or plates). However, balance is the preferred term for an instrument used for the precise measurement of small weights or masses in amounts ranging from micrograms up to a few kilograms.
Industry:Science
An instrument that indicates the bearing, or angle of the direction in which an aircraft is pointing in the horizontal plane. A compass may indicate magnetic heading or bearing, bearing referenced to a radio signal source, or bearing with respect to an inertially maintained line of position.
Industry:Science
An instrument that is sensitive to the interference of two or more acoustic waves. It provides information on acoustic wavelengths that is useful in determining the velocity and absorption of sound in samples of gases, liquids, and materials, and it yields information on the nonlinear properties of solids.
Industry:Science
An instrument that measures angular speed, as that of a rotating shaft. The measurement may be in revolutions over an independently measured time interval, as in a revolution counter, or it may be directly in revolutions per minute. The instrument may also indicate the average speed over a time interval or the instantaneous speed. Tachometers are used for direct measurement of angular speed and as elements of control systems to furnish a signal as a function of angular speed.
Industry:Science
An instrument that measures electric power. For a complete discussion of power measurement in various types of electric circuits
Industry:Science
An instrument that measures temperature. Although this broad definition includes all temperature-measuring devices, they are not all called thermometers. Other names have been generally adopted. For a discussion of two such devices
Industry:Science
An instrument that measures the velocity of a flowing liquid or gas, usually understood to be the average velocity of fluid within a relatively small measuring volume. Velocimeters are distinct from flow meters, which measure spatially averaged velocity, or flow rate, across the cross section of a duct or channel. Depending on the nature of the flow and the objective of the measurement, a velocimeter may be used to measure a time-dependent flow velocity or a time-averaged value. Another characteristic of a velocimeter is its spatial resolution, namely the size of its measuring volume. Some velocimeters measure flow velocity in both magnitude and direction, whereas others only resolve a velocity component in a particular direction or plane. The term anemometer is sometimes used as synonymous to velocimeter, although, strictly speaking, the former term should apply only to instruments that measure air velocity.
Industry:Science
An instrument that utilizes focused acoustic waves to produce images of surface and subsurface features in materials, and to measure elastic properties on a microscopic scale. It has been used to image and measure local elastic properties in metals, ceramics, semiconductor integrated circuits, polymeric materials, and biological materials including individual cells.
Industry:Science
An instrument used for determining the masses of atoms or molecules found in a sample of gas, liquid, or solid. It is analogous to the optical spectroscope, in which a beam of light containing various colors (white light) is sent through a prism to separate it into the spectrum of colors present. In a mass spectroscope, a beam of ions (electrically charged atoms or molecules) is sent through a combination of electric and magnetic fields so arranged that a mass spectrum is produced. If the ions fall on a photographic plate which after development shows the mass spectrum, the instrument is called a mass spectrograph; if the spectrum is allowed to sweep across a slit in front of an electrical detector which records the current, it is called a mass spectrometer.
Industry:Science
