Difference between revisions of "Abbreviations"
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Latest revision as of 00:07, 12 May 2013
- BS - Beam Splitter
- DE - Difraction Efficiency
- DMD - Digital Micro-Mirror Device
- EASLM - Electrically Addressed Spatial Light Modulation
- H1 - A first generation hologram
- H2 - A hologram of a hologram (copy)
- H3 etc. - Sucessive generations of holograms
- HOE - Holographic Optical Element
- LASER - Light Amplification by Stimulated Emission of Radiation
- l - liters
- l - length
- LCD - Liquid Crystal Display
- m - meters
- m - mass
- M1, M2, M3 ect. - Mirror 1, Mirror 2, Mirror 3, etc.
- mJ/cm^2 - milliJoules per centimeter squared
- RH - Relative Humidity
- SBR - Single Beam Reflection
- SBT - Single Beam Transmission
- SF - Spatial Filter
- SI - International System of Units
- SLM - Spatial Light Modulator
- uJ/cm^2 - microJoules per centimeter squared
- " - Inch = 25.4 mm
- ' - Foot = 12 inches
Also see the Holography Glossary.
From Sergio on the Forum
Some post recommendations internationally acept:
SI writing style
- Symbols do not have an appended period/full stop (.) unless at the end of a sentence.
- Symbols are written in upright (Roman) type (m for metres, l for litres), so as to differentiate from the italic type used for variables (m for mass, l for length). By consensus of international standards bodies, this rule is applied independent of the font used for surrounding text.
- Symbols for units are written in lower case, except for symbols derived from the name of a person. For example, the unit of pressure is named after Blaise Pascal, so its symbol is written "Pa" whereas the unit itself is written "pascal". All symbols of prefixes larger than 103 (kilo) are also uppercase.
o The one exception is the litre, whose original symbol "l" is unsuitably similar to the numeral "1" or the uppercase letter "i" (depending on the typeface used), at least in many English-speaking countries. The American National Institute of Standards and Technology recommends that "L" be used instead, a usage which is common in the US, Canada, Australia (but not elsewhere). This has been accepted as an alternative by the CGPM since 1979. The cursive ℓ is occasionally seen, especially in Japan and Greece, but this is not currently recommended by any standards body. For more information, see Litre.
- The SI rule is that symbols of units are not pluralised, for example "25 kg" (not "25 kgs").
o The American National Institute of Standards and Technology has defined guidelines for American users of the SI.These guidelines give guidance on pluralizing unit names: the plural is formed by using normal English grammar rules, for example, "henries" is the plural of "henry". The units lux, hertz, and siemens are exceptions from this rule: they remain the same in singular and plural. Note that this rule only applies to the full names of units, not to their symbols.
- A space separates the number and the symbol, e.g. "2.21 kg", "7.3×102 m2", "22 K". Exceptions are the symbols for plane angular degrees, minutes and seconds (°, ′ and ″), which are placed immediately after the number with no intervening space.
- Spaces may be used as a thousands separator (1 000 000) in contrast to commas or periods (1,000,000 or 1.000.000) in order to reduce confusion resulting from the variation between these forms in different countries. In print, the space used for this purpose is typically narrower than that between words (commonly a thin space).
- Any line break inside a number, inside a compound unit or between number and unit should be avoided, but if necessary the latter option should be used.
- The 10th resolution of CGPM in 2003 declared that "the symbol for the decimal marker shall be either the point on the line or the comma on the line". In practice, the decimal point is used in English and the comma in most other European languages.
- Symbols for derived units formed from multiple units by multiplication are joined with a space or centre dot (·), for example "N m" or "N·m".
- Symbols formed by division of two units are joined with a solidus (⁄), or given as a negative exponent. For example, the "metre per second" can be written "m/s", "m s−1", "m·s−1". Only one solidus should be used, i.e. "kg·m−1·s−2" is preferable to "kg/m/s²", and "kg/m·s²" is something else. Many computer users will type the / character provided on computer keyboards, which in turn produces the Unicode character U+002F, which is named solidus but is distinct from the Unicode solidus character, U+2044.
- In Chinese, Japanese, and Korean language computing (CJK), some of the commonly used units, prefix-unit combinations, or unit-exponent combinations have been allocated predefined single characters taking up a full square. Unicode includes these in its CJK Compatibility and Letterlike Symbols subranges for back compatibility, without necessarily recommending future usage.
- When writing dimensionless quantities, the terms 'ppb' (parts per billion) and 'ppt' (parts per trillion) are recognised as language-dependent terms since the value of billion and trillion can vary from language to language. SI therefore recommends avoiding these terms . However, no alternative is suggested by the International Bureau of Weights and Measures (BIPM).