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Particle Mass Analyser
Particle mass analyser is a measurement technique for classifying aerosol particles according to their mass-to-charge ratio. Techniques exist for classifying (selecting) aerosol particles in the sub 1,000 nm range according to electrical mobility using devices such as differential mobility analysers. Electrical mobility In electrical mobility measurement, aerosol particles are classified according to their aerodynamic drag-charge ratio. If the particle is non-spherical, the electrical-mobility diameter will not correspond to any measurable physical dimensions of the particle. (For a spherical particle, the electrical-mobility diameter will correspond to physically measurable diameter.) Centrifugal particle mass analyzer An alternative technique classifies particles according to their mass-to-charge ratio, using opposing electrical and centrifugal forces. This allows the classifier to select particles of a specified mass-to-charge ratio independent of particle shape. Further ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aerosol
An aerosol is a suspension (chemistry), suspension of fine solid particles or liquid Drop (liquid), droplets in air or another gas. Aerosols can be natural or Human impact on the environment, anthropogenic. Examples of natural aerosols are fog or mist, dust, forest exudates, and geyser steam. Examples of anthropogenic aerosols include particulate air pollutants, mist from the discharge at Hydroelectric dam, hydroelectric dams, Irrigation, irrigation mist, Perfume, perfume from atomizers, smoke, steam from a kettle, Pesticide, sprayed pesticides, and medical treatments for respiratory illnesses. When a person inhales the contents of a vape pen or e-cigarette, they are inhaling an Human impact on the environment, anthropogenic aerosol. The liquid or solid particles in an aerosol have diameters typically less than micrometre, 1 μm (larger particles with a significant settling speed make the mixture a Suspension (chemistry), suspension, but the distinction is not clear-cut) ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electrical Mobility
Electrical mobility is the ability of charged particles (such as electrons or protons) to move through a medium in response to an electric field that is pulling them. The separation of ions according to their mobility in gas phase is called ion mobility spectrometry, in liquid phase it is called electrophoresis. Theory When a charged particle in a gas or liquid is acted upon by a uniform electric field, it will be accelerated until it reaches a constant drift velocity according to the formula : v_\text = \mu E, where : v_\text is the drift velocity ( SI units: m/s), : E is the magnitude of the applied electric field (V/m), : \mu is the mobility (m2/(V·s)). In other words, the electrical mobility of the particle is defined as the ratio of the drift velocity to the magnitude of the electric field: : \mu = \frac. For example, the mobility of the sodium ion (Na+) in water at 25 °C is . This means that a sodium ion in an electric field of 1 V/m would have an averag ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mass-to-charge Ratio
The mass-to-charge ratio (''m''/''Q'') is a physical quantity relating the ''mass'' (quantity of matter) and the ''electric charge'' of a given particle, expressed in units of kilograms per coulomb (kg/C). It is most widely used in the electrodynamics of charged particles, e.g. in electron optics and ion optics. It appears in the scientific fields of electron microscopy, cathode ray tubes, accelerator physics, nuclear physics, Auger electron spectroscopy, cosmology and mass spectrometry. The importance of the mass-to-charge ratio, according to classical electrodynamics, is that two particles with the same mass-to-charge ratio move in the same path in a vacuum, when subjected to the same electric and magnetic fields. On rare occasions, the thomson has been used as its unit in the field of mass spectrometry. Some disciplines use the charge-to-mass ratio (''Q''/''m'') instead, which is the multiplicative inverse of the mass-to-charge ratio. The CODATA recommended value for an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Centrifugal Force
In Newtonian mechanics, the centrifugal force is an inertial force (also called a "fictitious" or "pseudo" force) that appears to act on all objects when viewed in a rotating frame of reference. It is directed away from an axis which is parallel to the axis of rotation and passing through the coordinate system's origin. If the axis of rotation passes through the coordinate system's origin, the centrifugal force is directed radially outwards from that axis. The magnitude of centrifugal force ''F'' on an object of mass ''m'' at the distance ''r'' from the origin of a frame of reference rotating with angular velocity is: F = m\omega^2 r The concept of centrifugal force can be applied in rotating devices, such as centrifuges, centrifugal pumps, centrifugal governors, and centrifugal clutches, and in centrifugal railways, planetary orbits and banked curves, when they are analyzed in a rotating coordinate system. Confusingly, the term has sometimes also been used for the reactiv ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Measuring Instruments
A measuring instrument is a device to measure a physical quantity. In the physical sciences, quality assurance, and engineering, measurement is the activity of obtaining and comparing physical quantities of real-world objects and events. Established standard objects and events are used as units, and the process of measurement gives a number relating the item under study and the referenced unit of measurement. Measuring instruments, and formal test methods which define the instrument's use, are the means by which these relations of numbers are obtained. All measuring instruments are subject to varying degrees of instrument error and measurement uncertainty. These instruments may range from simple objects such as rulers and stopwatches to electron microscopes and particle accelerators. Virtual instrumentation is widely used in the development of modern measuring instruments. Time In the past, a common time measuring instrument was the sundial. Today, the usual measuring instru ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Scientific Instruments
A scientific instrument is a device or tool used for scientific purposes, including the study of both natural phenomena and theoretical research. History Historically, the definition of a scientific instrument has varied, based on usage, laws, and historical time period. Before the mid-nineteentcenturysuch tools were referred to as "natural philosophical" or "philosophical" apparatus and instruments, and older tools from antiquity to the Middle Ages (such as the astrolabe and pendulum clock) defy a more modern definition of "a tool developed to investigate nature qualitatively or quantitatively." Scientific instruments were made by instrument makers living near a center of learning or research, such as a university or research laboratory. Instrument makers designed, constructed, and refined instruments for purposes, but if demand was sufficient, an instrument would go into production as a commercial product. In a description of the use of the eudiometer by Jan Ingenhousz to show ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Scientific Techniques
A scientific technique is any systematic way of obtaining information about a scientific nature or to obtain a desired material or product. Scientific techniques can be divided in many different groups, e.g.: # Preparative techniques ## Synthesis techniques, e.g. the use of Grignard reagents in organic chemistry ## Growth techniques, e.g. crystal growth or cell cultures in biology ## Purification techniques e.g. those in chemistry # Measurement techniques ## Analysis techniques, e.g. ones that reveal atomic or molecular composition. ## Characterization techniques, e.g. ones that measure a certain property of a material. ## Imaging techniques, e.g. microscopy In some cases these methods have evolved into instrumental techniques that require expensive equipment. This is particularly true in sciences like physics, chemistry, and astronomy. It is customary to abbreviate the names of techniques into acronyms, although this does not hold for all of them. Particularly the advent of th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
