MKS system

The metre-kilogram-second (mks system and the Systeme International d Unites (SI)... 

It should be noted that a force in the cgs system is sometimes expressed as a gram force and in the mks system as kilogram force, although this is not good practice. It should also be noted that the gram force = 980.665 dyne and the kilogram force = 9.80665 N)... 

Prior to the now almost universal adoption of the SI system of units, the unit of heat was defined as the quantity of heat required to raise the temperature of unit mass of water by one degree. This heat quantity is designated the calorie in the cgs system and the kilocalorie in the mks system, and in both cases temperature is expressed in degrees Celsius (Centigrade). As the specific heat capacity is a function of temperature, it has been necessary to set a datum temperature which is chosen as 298 K or 25°C. 

In all of these systems, by definition, the specific heat capacity of water is unity. It may be noted that, by comparing the definitions used in the SI and the mks systems, the kilocalorie is equivalent to 4186.8 J/kg K. This quantity has often been referred to as the mechanical equivalent of heat J. 

Using the symbol B for the magnetic field technically implies we are using the MKS system of units in which B is given in Tesla (T). Many spectroscopists still express the magnetic field in Gauss (G) — 10 4 T, however, and we will continue that practice here. 

We note, furthermore, that Eq. 5.1 and most of the following relationships are here expressed in the International System of Units (SI), also called the mks system conversion to cgs units is readily accomplished by replacing the factor l/(47i o) by unity. For comparison with measurements, it is customary to use frequencies v in wavenumber units (cm-1). Conversion to these units is accomplished by replacing frequency co (in units of radians/second) by 2ncv, where c designates the speed of light in vacuum furthermore, we replace (5(co) by the identical 3(v)/2nc. 

In 1960, the eleventh General Conference on Weights and Measures recommended the International System of Units (Systeme International d Unites), abbreviated as SI units, for use in science SI units are essentially the rationalized mks system of units. Relations between SI units and Gaussian units are given in Table A.4 of the Appendix. Table A.5 allows one to convert equations from SI to Gaussian units. 

In the MK system, most J-type stars are classified as C4-5 4-5 stars which show very strong C and CN bands. Yamashita(l972,l975) classified many C7-9 stars most of which are CS or SC stars. His classification of C7-9J stars is mainly based on Cl2Cl3(0,l)band at 6168 A, C13N(4,0)band at 6260 A, and Lil 6708 A line. In most of C7-9 stars, lines of s-process elements are greatly enhanced. It is a question if in all J-type stars abundances of s-process elements are nearly normal or not. 

The basic unit of radioactivity is the curie, Ci. One curie is the amount of radioactive material that emits particles at a rate of 3.7 X 1010 disintegrations per second (dps), or 2.2 X 1012 min-1 (dpm). Amounts that large are seldom used in experimentation, so subdivisions are convenient. The milli-curie (mCi, 2.2 X 109 min-1) and microcurie (yu,Ci, 2.2 X 106 min-1) are standard units for radioactive measurements (see Table 6.2). The radioactivity unit of the meter-kilogram-seconds (MKS) system is the becquerel (Bq). A becquerel, named in honor of Antoine Becquerel, who studied uranium radiation, represents one disintegration per second. The two systems of measurement are related by the definition 1 curie = 3.70 X 1010 becquerels. Since the becquerel is such a small unit, radioactive units are sometimes reported in MBq (mega, 106) or TBq (tera, 1012). Both unit systems are in common use today, and radioisotopes received through commercial sources are labeled in curies and bequerels. 

In the cgs system, power has the units of ergs per second in the mks system, units of joules per second lor watts) and in the English system, units of foot-pounds per second. A common engineering unit is the horsepower, defined as 550 foot-pounds per second or 33.000 footpounds per minute. The SI unit of power is the wall. I watt = I joule per second. < I joule is the work done by I newton acting through a distance of I meler.l I joule = watt-second = I07 ergs= I07 dyne-centimeters. The SI unil of force is the newton. (I newton = 10s dynes). See also entry on Units and Standards. 

In the MKS system of units, standard atmospheric pressure is 750 torr and is expressed as 100,000 Pa (N/m2) or 100 kPa. This means that 1 Pa is equivalent to 7.5 millitorr (1 torr = 133.3 pascal). Vacuum, usually expressed in inches of mercury, is the depression of pressure below the atmospheric level, with absolute zero pressure corresponding to a vacuum of 30 inches of mercuiy. 

Note that above we so far employed the absolute (CGS) system of units. Since in most publications deovted to electrolytes SI (MKS) system is usually used, we shall below duplicate the formula for both systems (if these formulas... 

In the MKS system of units, s0 is the dielectric constant of vacuum given by... 

We start from Maxwell equations. Using the MKS system of units, we have for wave vector k perpendicular to electric field E the equation [see Eq. (3)]... 

Napoleon s armies spread the system throughout continental Europe, but the British (and consequently the Americans) hung to the old English inch-pound-second system. From cgs the kilogram-meter-second (mks) system evolved, and finally SI (Systeme International d Unites) was bom from mks with the addition of units of current (ampere), temperature (kelvin), and brightness (candela). The International Temperature Scale is defined by 13.8033 K (triple point of equilibrium H2) 24.5561 K (triple point of Ne) and 1234.93 K (freezing temperature of Ag). 

Using the cgs system with the dyne as the unit of force and erg as the unit of work is impractical for many applications (too large or too small numbers to work with), so the mks system of units is preferred. Then the force is in newtons (1 N = 105 dyn), and the unit of work is the joule (1 J = 107 erg). A rate of doing work of 1 J/s is 1 W. A watt is also a measure of electrical power, being 1 A flowing with a potential of 1 V. 

Finally, the magnitude of the electrical quantities must be chosen. Often the ampere is taken as the defining unit, and from the definition of the ampere a term l/(p0c2) = e0 arises. In the rationalized mks system x0 = 4tt x 10-7 N/A2 and then e0 = 8.8542 x 1012. 

The basic electrostatic units (esu), however, are the unrationalized cgs units. Hence, to convert from unrationalized cgs units to the rationalized mks system of units, start with the relationship... 

The lessons learned from the photophysical study of the BP/MK system influence methods to optimize photopolymer imaging systems. Since MK absorbs most of the light in this system, one wishes to optimize the amount of MK used for the thickness of the photoimaging composition, but the self-quenching of MK should also be minimized. Since the BP functions basically as a quencher, its concentration should be as high as is practicable [51],... 

Though it seems inconsistent, the SI base unit is the gram-mole. As Mario Iona reminds me, SI is not an MKS system. Some textbooks still prefer to use use the kilogram-mole, or worse, use it... 

Per unit. In my opinion this expression is a barbarism best avoided. When a student is told that electric field is force per unit Charge and in the MKS system one unit of charge is a coulomb (a huge amount) must we obtain that much charge to measure the field Certainly not. 

All macroscopic aspects of the statics and dynamics of electromagnetic field in the presence of material media are described by Maxwell s equations. The differential form of these axioms in the International System of Units (SI) or rationalized MKS system (Cohen and Giacomo, 1987 Lide, 1991) is given in... 

Dorken MKS-Systeme GmbH Go. KG, DELTA-PROTEKT, company information, Herdecke, Germany, 2004... 

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