- 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.
The selective hardening of the surface layer of a steel product by one of several processes which involve changes in microstructure with or without changes in composition. Surface hardening imparts a combination of properties to the finished product not produced by bulk heat treatment alone. Among these properties are high wear resistance and good toughness or impact properties, increased resistance to failure by fatigue resulting from cyclic loading, and resistance to surface indentation by localized loads. The use of surface hardening frequently is also favored by lower costs and greater flexibility in manufacturing.
Industry:Science
The movement, protection, storage, and control of materials and products throughout the process of their manufacture, distribution, consumption, and disposal, as defined by the Material Handling Industry of America. Materials handling is not just about equipment for storage and movement, it also includes controls that direct movement, packaging tools, and techniques that protect goods as they flow from point to point. However, no amount of equipment, automation, or information technology can take the place of a well-designed system that facilitates the steady flow of goods through manufacturing and distribution facilities.
Industry:Science
The motion of electrons inside atoms and molecules occurs with awesome rapidity. Quantum mechanics predicts that the electron (in the language of quantum mechanics, the electron wavepacket) of a hydrogen atom takes about 400 attoseconds (1 as = 10−18 s) to perform an oscillation around the nucleus when it is most closely bound to it. The electron wavepacket on a molecular orbit binding two hydrogen atoms together to form a molecule takes approximately the same time to circle around the hydrogen nuclei. No one has ever been able to observe these hyperfast electron motions in real time. Attosecond pulses open up this prospect.
Industry:Science
The phenomenon occurring in the special theory of relativity wherein two observers who start together with identical clocks and then undergo different motions can have different total elapsed time on their clocks when they rejoin later. This effect is a well-defined, mathematically consistent prediction of special relativity which has been verified by experiment but, historically, it has been referred to as a paradox because of erroneous reasoning in the manner in which the effect is commonly analyzed. The clock-paradox phenomenon arises because there is no notion of absolute simultaneity in the theory of special relativity.
Industry:Science
The study of the resonant response to microwave- or radio-frequency radiation of paramagnetic materials placed in a magnetic field. It is sometimes referred to as electron spin resonance (ESR). Paramagnetic substances normally have an odd number of electrons or unpaired electrons, but sometimes electron paramagnetic resonance (EPR) is observed for ions or biradicals with an even number of electrons. EPR spectra are normally presented as plots of the first derivative of the energy absorbed from an oscillating magnetic field at a fixed microwave frequency versus the magnetic field strength. The dispersion may also be detected.
Industry:Science
The motion of that portion of the atmosphere that extends in altitude roughly from 10 to 100 km (6 to 60 mi). Interest in the middle atmosphere has been fueled by concerns over the Earth's environment, and in particular by the discovery of the ozone hole in the Antarctic lower stratosphere, together with predictions of greenhouse warming. Among the most difficult and important tasks in atmospheric science are unequivocal determinations of long-term changes in both amount of ozone and greenhouse-induced global temperature. Both are intimately related to the composition, structure, and dynamical motions in the middle atmosphere.
Industry:Science
The processes and techniques used for converting the mechanical vibrational energy of solids into heat energy. While vibration damping is helpful under conditions of resonance, it may be detrimental in many instances to a system at frequencies above the resonant point. This is due to the fact that the relative motion between the base of the vibration isolator and the mounted body tends to become smaller as the isolator becomes more efficient at the higher frequencies. With damping present, the force transmitted by the elastic element is unable to overcome the damping force; this leads to a resulting increase in transmissibility.
Industry:Science
The production of a product, process, or piece of equipment on a simulated factory basis. In mass-production industries where complicated products, processes, or equipment are being developed, a pilot plant often leads to the presentation of a better product to the customer, lower development and manufacturing costs, more efficient factory operations, and earlier introduction of the product. Following the engineering development of a product, process, or complicated piece of equipment and its one-of-a-kind fabrication in the model shop, it becomes desirable and necessary to “prove out” the development on a simulated factory basis.
Industry:Science
The motion of the atmosphere above 50 km (30 mi). The predominant dynamical phenomena of the upper atmosphere are quite different from those encountered in the lower atmosphere. Among those encountered in the lower atmosphere are cyclones, anticyclones, tropical hurricanes, thunderstorms and shower clouds, tornadoes, and dust devils. Even the largest of these phenomena do not penetrate far into the upper atmosphere. Above an altitude of about 50 km (30 mi), the predominant dynamical phenomena are internal gravity waves, tides, sound waves (including infrasonic), turbulence, and large-scale circulation. These are described below.
Industry:Science
The mouth, or oral cavity, which comprises the lips, tongue, teeth, gums, and related structures, is subject to a large number of disease processes. Periodontitis, an inflammatory disease of the tissues supporting and surrounding the teeth, and dental decay are the most common diseases; together they account for almost all tooth loss. Other diseases of the mouth can be classified as cysts; diseases of the salivary glands; keratotic, inflammatory, ulcerative, and proliferative lesions; oral infections; and an unusual form of rapidly destructive periodontitis observed in some patients with acquired immune deficiency syndrome (AIDS).
Industry:Science
