scientific abbreviations and symbols

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a absorption coefficient, acceleration, activitya0 Bohr radiusA ampere, adenine (in genetic code)Å ångstromA absorbance, area, Helmholtz energy, mass numberAH Hall coefficientAr atomic weight (relative atomic mass)AAS atomic absorption spectroscopyAbe abequoseabs absoluteac alternating currentAc acetylAcOH acetic acidACT activated complex theoryACTH adrenocorticotropic hormoneAde adenineADP adenosine diphosphateads adsorptionae eon (109 years)AES atomic emission spectroscopy,

Auger electron spectroscopyAF audio frequencyAFM atomic force microscopyAI artificial intelligenceAIM atoms in moleculesAl Alfen numberAla alaninealc alcoholaliph. aliphaticalk. alkalineAll alloseAlt altroseam amorphous solidAm amylAM amplitude modulationAMP adenosine 5'-monophosphateamu atomic mass unit (recommended symbol is u)anh, anhyd anhydrousantilog antilogarithmAO atomic orbitalAOM angular overlap modelApi apioseAPS appearance potential spectroscopyAPW augmented plane waveaq aqueousAr arylAra arabinoseAra-ol arabinitolArg arginine

SCIENTIFIC ABBREVIATIONS AND SYMBOLS

This table lists some symbols, abbreviations, and acronyms encountered in the physical sciences. Most entries in italic type are symbols forphysical quantities; for more details on these, see the table “Symbols and Terminology for Physical and Chemical Quantities” in this section.Additional information on units may be found in the table “International System of Units” in Section 1. Many of the terms to which theseabbreviations refer are included in the tables “Definitions of Scientific Terms” in Section 2 and “Techniques for Materials Characterization” inSection 12.

Publication practices vary with regard to the use of capital or lower case letters for many abbreviations. An effort has been made to follow themost common practices in this table, but much variation is found in the literature. Likewise, policies on the use of periods in an abbreviation varyconsiderably. Periods are generally omitted in this table unless they are necessary for clarity. Periods should never appear in SI units. The SIprefixes (m, k ,M, etc.) are not listed here, since they should never be used alone, but selected combinations with SI units (e.g., mg, kV, MW) areincluded.

Abbreviations are listed in alphabetical order without regard to case. Entries beginning with Greek letters fall at the end of the table.

as, asym asymmetrical (as chemical descriptor)ASCII American National Standard Code for Information

InterchangeASE aromatic stabilization energyAsn asparagineAsp aspartic acidat atomizationatm standard atmosphereATP adenosine 5'-triphosphateATR attenuated total internal reflectionat.wt. atomic weightAU astronomical unitav averageavdp avoirdupoisb barnB magnetic flux density, second virial coefficient,

susceptancebar bar (pressure unit)bbl barrelbcc body centered cubicBCS Bardeen-Cooper-Schrieffer (theory)BDE bond dissociation energyBé BauméBET Brunauer-Emmett-Teller (method)BeV billion electronvoltBhn Brinell hardness numberBi biotBN bond numberBNS nuclear backscattering spectroscopyBO bond order, Born-Oppenheimer (approximation)BOD biochemical oxygen demandbp boiling pointbpy 2,2'-bipyridineBq becquerelBRE bond resonance energyBSSE basis set superposition errorBtu British thermal unitbu bushelBu butylBz benzoylBzl benzylc combustion reactionc amount concentration, specific heat, velocityc0 speed of light in vacuumC coulomb, cytosine (in genetic code)°C degree CelsiusC capacitance, heat capacity, number concentrationca. approximatelycal calorie

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calc calculatedCARS coherent anti-Stokes Raman spectroscopyCAS RN Chemical Abstracts Service Registry NumberCAT clear-air turbulence, computerized axial tomographyCBS complete basis setcc cubic centimeterCCD charge-coupled devicecd candela, condensed phasec.d. current densityCD circular dichroismCDP cytidine 5'-diphosphateCEPA couplet electron pair approximationcf. comparecfm cubic feet per minutecgs centimeter-gram-second systemCHF coupled Hartree-Fock (method)Ci curieCI configuration interaction, chemical ionizationCIDEP chemically induced dynamic electron polarizationCIDNP chemically induced dynamic nuclear polarizationcir circularCKFF Cotton-Kraihanzel force fieldCL cathode luminescencecm centimeterc.m. center of massc.m.c. critical micelle concentrationCMO canonical molecular orbitalCMP cytidine 5'-monophosphateCN coordination numberCNDO complete neglect of differential overlapCo Cowling numberCOD chemical oxygen demandconc concentrated, concentrationconst constantcos cosinecosh hyperbolic cosineCOSY correlation spectroscopy (in NMR)cot cotangentcoth hyperbolic cotangentcp candle powercP centipoiseCp cyclopentadienylCP chemically pureCPA coherent potential approximationcpd contact potential differencecps cycles per secondCPT charge conjugation-space inversion-time reversal

(theorem)CPU central processing unitcr, cryst crystalline (phase)CRU constitutional repeating unitcsc cosecantct caratCT charge transferCTEM conventional transmission electron microscopyCTP cytidine 5'-triphosphateCTR controlled thermonuclear reactioncu cubicCV cyclic voltammetryCVD chemical vapor depositioncw continuous wave

cwt hundredweight (112 pounds)Cy cyclohexylcyl cylinderCys cysteined day, deuterond distance, density, dextrorotatoryD debye unitD diffusion coefficient, dissociation energy, electric

displacementDa daltonDA donor-acceptor (complex)dB decibeldc direct currentDE delocalization energydec decomposesdeg degreeden densitydet determinantdev deviationDFT density functional theorydiam diameterdil dilute, dilutionDIM diatomics in moleculesdm decimeterdmf, DMF N,N-dimethylformamidedmso, DMSO dimethylsulfoxideDNA deoxyribonucleic acidDNase deoxyribonucleaseDNMR dynamic nuclear magnetic resonanceDOS density of statesdoz dozend.p. degree of polymerizationdpl displacementdpm disintegrations per minutedps disintegrations per seconddr dramdRib 2-deoxyriboseDRIFT diffuse reflectance infrared Fourier transformDRS diffuse reflectance spectroscopyDSC differential scanning calorimetryDTA differential thermal analysisdyn dynee electron, base of natural logarithmse elementary charge, linear strainE electric field strength, electromotive force, energy,

modulus of elasticity, entgegen (trans configuration)Eh Hartree energyEA electron affinityEAN effective atomic numberECP effective core potentialECR electron cyclotron resonanceED electron diffraction, effective doseEDS energy dispersive X-ray spectroscopyEDTA ethylenediaminetetraacetic acidEELS electron energy loss spectroscopyEFFF energy factored force fieldEHMO extended Hückel molecular orbitalEHT extended Hückel theoryemf electromotive forceemu electromagnetic unit systemen ethylenediamine

SCIENTIFIC ABBREVIATIONS AND SYMBOLS (continued)

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ENDOR electron-nuclear double resonanceEOS equation of stateEPMA electron probe microanalysisEPR electron paramagnetic (spin) resonanceeq, eqn equationeqQ quadrupole coupling constanterf error functionerg ergESCA electron spectroscopy for chemical analysise.s.d. estimated standard deviationESD electron stimulated desorptionESR electron spin resonanceest estimate, estimatedesu electrostatic unit systemEt ethylET electron transfer, ephemeris timeEt2O diethyl ethere.u. entropy unitEu Euler numbereV electronvoltEWG electron withdrawing groupEXAFS extended x-ray absorption fine structureEXELFS extended energy loss fine structureexp exponential functionexpt experimentalext externalf formation reactionf activity coefficient, aperture ratio, focal length,

force constant, frequency, fugacityF farad°F degree FahrenheitF Faraday constant, force, angular momentumFAD flavin adenine dinucleotidefcc face centered cubicFEL free electron laserFEM field emission microscopyFEMO free electron molecular orbitalFET field effect transistorfid free induction decayFIM field ion microscopyFIR far infraredfl fluid (phase)FM frequency modulationFo Fourier numberfp freezing pointfpm feet per minutefps feet per second, foot-pound-second systemFr franklinFr Froude numberFru fructoseFSGO floating spherical Gaussian orbitaìft footft-lb foot poundFT Fourier transformFTIR Fourier transform infrared spectroscopyFuc fucoseFuc-ol fucitolfus fusion (melting)g gram, gasg acceleration due to gravity, degeneracy, statistical

weight, Landé g-factor

G gauss, guanine (in genetic code)G electrical conductance, Gibbs energy, gravitational

constant, sheer modulusgal gallonGal gal, galileo, galactoseGalN galactosamineGC gas chromatographyGC-MS gas chromatography-mass spectrometryGDMS glow discharge mass spectroscopygem geminal (on the same carbon atom)GeV gigaelectronvoltGIAO gauge invariant atomic orbitalgl glacialGLC gas-liquid chromatographyGlc glucoseGlcN glucosamineGlc-ol glucitolGln glutamineGlu glutamic acidGly glycineGMP guanosine 5'-triphosphateGMT Greenwich mean timegpm gallons per minutegps gallons per secondgr grainGr Grashof numberGTO gaussian type atomic orbitalGua guanineGul guloseGUT grand unified theoryGVB generalized valence bondGWS Glashow-Weinberg-Salam (theory)Gy gray, gigayearh helion, hourh Planck constantH henryH enthalpy, Hamiltonian function, magnetic fieldH0 Hubble constantha hectareHa Hartmann numberHacac acetylacetoneHAM hydrogenic atoms in moleculeshav haversineHb hemoglobinhcp hexagonal closed packedHea ethanolamineHEIS high energy ion scatteringHEP high energy physicsHF high frequencyhfs hyperfine structureHim imidazoleHis histidineHMO Hückel molecular orbitalHOMO highest occupied molecular orbitalhp horsepowerHPLC high-performance liquid chromatographyHpz pyrazolehr hourHREELS high resolution electron energy loss spectroscopyHREM high resolution electron microscopyHSAB hard-soft acid-base (theory)


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HSE homodesmotic stabilization energyHz hertzi square root of minus oneI electric current, ionic strength, moment of inertia,

nuclear spin angular momentum, radiant intensityIAT international atomic timei-Bu isobutylIC integrated circuitICP inductively coupled plasmaICR ion cyclotron resonanceid ideal (solution)ID inside diameterIdo idoseIDP inosine 5'-diphosphateIE ionization energyi.e.p. isoelectric pointIEPA independent electron pair approximationIF intermediate frequencyIGLO individual gauge for localized orbitalsIle isoleucineIm imaginary partimm immersionIMPATT impact ionization avalanche transit timein. inchINDO intermediate neglect of differential overlapINS inelastic neutron scattering, ion neutralization

spectroscopyint internalI/O input/outputIP ionization potentialIPN interpenetrating polymer networki-Pr isopropylIPR isotopic perturbation of resonanceIPTS International Practical Temperature ScaleIR infraredIRAS reflection-absorption infrared spectroscopyIRC intrinsic reaction coordinateisc intersystem crossingISE isodesmic stabilization energyISS ion scattering spectroscopyITP inosine 5'-triphosphateITS International Temperature Scale (1990)IU international unitj angular momentum, electric current densityJ jouleJ angular momentum, electric current density, flux,

Massieu functionk absorption index, Boltzmann constant, rate constant,

thermal conductivity, wave vectorK kelvinK absorption coefficient, bulk modulus, equilibrium

constant, kinetic energykb kilobar, kilobase (DNA or RNA)kcal kilocalorieKE kinetic energykeV kiloelectronvoltkg kilogramkgf kilogram forcekJ kilojoulekm kilometerKn Knudsen number

kPa kilopascalkt karatkV kilovoltkva kilovolt amperekW kilowattkwh kilowatt hourl liquid, literl angular momentum, length, levorotatoryL liter, lambertL Avogadro constant, inductance, Lagrange functionlat. latitudelb poundlbf pound forcelc liquid crystalLC liquid chromatographyLCAO linear combination of atomic orbitalsLD lethal doseLe Lewis functionLED light emitting diodeLEED low-energy electron diffractionLEIS low energy ion scatteringLeu leucineLFER linear free energy relationshiplim limitLIMS laser ionization mass spectroscopy, laboratory

information management systemliq liquidlm lumenln logarithm (natural)LNDO local neglect of differential overlaplog logarithm (common)long. longitudeLST local sidereal timeLT local timeLTE local thermodynamic equilibriumLUMO lowest unoccupied molecular orbitallut lutidinelx luxly langleyl.y. light yearLys lysineLyx lyxosem meter, molal (as in 0.1 m solution), metastable

(isotope)m magnetic dipole moment, mass, molality, angular

momentum component, meta (as chemical descriptor)M molar (as in 0.1 M solution), metal (in chemical

formulas)M magnetization, molar mass, mutual inductance, torque,

angular momentum componentMr molecular weight (relative molar mass)Ma Mach numberMan mannoseMASNMR magic angle spinning nuclear magnetic resonancemax maximumMBE molecular beam epitaxyMBPT many body perturbation theoryMC Monte Carlo (method)MCD magnetic circular dichroismMCPF modified couple pair functionalMCSCF multi-configurational self-consistent field


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MD molecular dynamicsMe methylMEP molecular electrostatic potentialMERP minimum energy reaction pathMes mesitylMESFET metal-semiconductor field-effect transistorMet methioninemeV millielectronvoltMeV megaelectronvoltMF molecular formulamg milligramMHD magnetohydrodynamicsmi mileMIM molecules-in-moleculesmin minimum, minuteMINDO modified intermediate neglect of differential overlapMIR mid-infraredmisc miscibleMKS meter-kilogram-second systemMKSA meter-kilogram-second-ampere systemmL, ml millilitermm millimeterMM molecular mechanicsmmf magnetomotive forcemmHg millimeter of mercuryMO molecular orbitalmol molemol.wt. molecular weightmon monomeric formMOS metal-oxide semiconductorMOSFET metal-oxide semiconductor field-effect transistormp melting pointMPa megapascalMPA Mulliken population analysisMpc megaparsecMRI magnetic resonance imagingmRNA messenger RNAms millisecondMS mass spectroscopyMSL mean sea levelMur muramic acidmV millivoltmW milliwattMW megawatt, microwave, molecular weightMx maxwelln neutronn amount of substance, number density, principal

quantum number, refractive index, normal (inchemical formulas)

N newtonN angular momentum, neutron numberNA Avogadro constantNE density of statesNAA neutron activation analysisNAD nicotinamide adenine dinucleotideNADH reduced NADNADP nicotinamide adenine dinucleotide phosphateNAO natural atomic orbitalNBO natural bond ordernbp normal boiling pointNeu neuraminic acid

NEXAFS near-edge x-ray absorption fine structureng nanogramNIR near infrarednm nanometerNMR nuclear magnetic resonanceNNDO neglect of nonbonded differential overlapNO natural orbitalNOE nuclear Overhauser effectNPA natural population analysisNQR nuclear quadrupole resonanceNRA prompt nuclear reaction analysisns nanosecondNTP normal temperature and pressureNu nucleophileNu Nusselt numbero ortho (as chemical descriptor)obs, obsd observedOD optical density, outside diameterOe oerstedORD optical rotatory dispersionoz ouncep protonp dielectric polarization, electric dipole moment,

momentum, pressure, para (as chemical descriptor)P poiseP power, pressure, probability, sound energy fluxPa pascalPA proton affinityPAS photoacoustic spectroscopypc parsecPCR polymerase chain reactionPD potential differencepdl poundalpe probable errorPe Péclet numberPES photoelectron spectroscopyPET positron emission tomographypeth petroleum etherpf power factorpg picogrampH negative log of hydrogen ion concentrationPh phenylPhe phenylalaninepI isoelectric pointpip piperidinepK negative log of ionization constantpm picometerPMO perturbational molecular orbitalPNDO partial neglect of differential overlapPNRA prompt nuclear reaction analysispol polymeric formppb parts per billionppm parts per millionPPP Pariser-Parr-Pople (method)ppt parts per thousand, precipitatePr propylPr Prandtl numberPRDDO partial retention of diatomic differential overlapPro prolineps picosecondPS photoelectron spectroscopy


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PSD photon stimulated desorptionPsi psicosepsi pounds per square inchpsia pounds per square inch absolutepsig pounds per square inch gagept pintPVT pressure-volume-temperaturepy pyridineq electric field gradient, flow rate, heat, wave vector

(phonons)Q electric charge, heat, partition function, quadrupole

moment, radiant energy, vibrational normal coordinateQCD quantum chromodynamicsQED quantum electrodynamicsQ.E.D. quod erat demonstrandum (which was to be proved)QSAR quantitative structure-activity relationshipQSO quasi-stellar object (quasar)qt quartquad quadrillion Btu (= 1.0551018 J)Qui quinovoseq.v. quod vide (which you should see)r reactionr position vector, radiusR roentgen, alkyl radical (in chemical formulas)°R degree RankineR electrical resistance, gas constant, molar refraction,

Rydberg constantRA right ascensionrad radianRAIRS reflection-absorption infrared spectroscopyRAM random access memoryRBS Rutherford backscattering spectroscopyRE resonance energyRe real partRED radial electron distributionREM reflection electron microscopyrem roentgen equivalent manRF radiofrequencyRha rhamnoseRHEED reflection high-energy electron diffractionRHF restricted Hartree-Fock (theory)RIA radioimmunoassayRib riboseRibulo ribuloserms root mean squareRNA ribonucleic acidRNase ribonucleaserRNA ribosomal RNAROHF restricted open shell Hartree-FockROM read only memoryRPA random phase approximationrpm revolutions per minuterps revolutions per secondRRK Rice-Ramsperger-Kassel (theory)RRKM Rice-Ramsperger-Kassel-Marcus (theory)RRS resonance Raman spectroscopyRS Raman spectroscopyRy rydbergs second, solids path length, solubility, spin angular momentum,

symmetry number, symmetrical (as stereochemicaldescriptor)

S siemensS area, entropy, probability current density, Poynting

vector, symmetry coordinate, spin angular momentumSALC symmetry adapted linear combinationsSALI surface analysis by laser ionizationSAM scanning Auger microscopySANS small angle neutron scatteringSar sarcosinesat, satd saturatedSAXS small angle x-ray scatterings-Bu sec-butylSc Schmidt numberSCE saturated calomel electrodeSCF self-consistent fieldSCR silicon-controlled rectifiersd standard deviationsec secant, secondsec secondary (in chemical name)SEELFS surface sensitive energy loss fine structureSEM scanning electron microscopesepn separationSer serineSERS surface-enhanced Raman spectroscopySET single electron transferSEXAFS surface extended x-ray absorption fine structureSh Sherwood numberSI International System of UnitsSIMS secondary ion mass spectroscopysin sineSINDO symmetrically orthogonalized INDO methodsinh hyperbolic sineSIPN semi-interpenetrating polymer networkSLAM scanning laser acoustic microscopysln solutionSMO semiempirical molecular orbitalSMOW Standard Mean Ocean WaterSNMS sputtered neutral mass spectroscopySNU solar neutrino unitSO spin orbitalsol soluble, solutionsoln solutionSOMO singly occupied molecular orbitalSor sorbosesp gr specific gravitySPM scanned probe microscopysq squaresr steradianSr Strouhal numberSSMS spark source mass spectroscopySt stokeSt Stanton numberstd, stnd standard (state)STEM scanning transmission electron microscopeSTM scanning tunneling microscopySTO Slater type orbitalSTP standard temperature and pressuresub sublimation, sublimesSv sievertt metric tonne, tritont Celsius temperature, thickness, time, transport

numberT tesla


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T kinetic energy, period, term value, temperature(thermodynamic), torque, transmittance

Tag tagatoseTal talosetan tangenttanh hyperbolic tangentt-Bu tert-butylTCA trichloroacetic acidTCE trichloroethylenetcne tetracyanoethyleneTCSCF two configuration self-consistent fieldTE transverse electricTED transmission electron diffraction, transferred electron

deviceTEM transmission electron microscopy, transverse

electromagnetictemp temperaturetert tertiary (in chemical name)TFD Thomas-Fermi-Dirac (method)TGA thermo-gravimetric analysistheor theoreticalthf, THF tetrahydrofuranThr threonineThy thymineTL thermoluminescenceTLC thin-layer chromatographyTM transverse magneticTol tolylTorr torrtRNA transfer RNATrp tryptophantrs transitionTS transition statetsp teaspoonTyr tyrosineu unified atomic mass unitu Bloch function, electric mobility, velocityU uracil (in genetic code)U electric potential difference, internal energyUDP uridine 5'-diphosphateUHF ultrahigh frequency, unrestricted Hartree-Fock

(theory)UMP uridine 5'-monophosphateuns, unsym unsymmetrical (as chemical descriptor)UPES ultraviolet photoelectron spectroscopyUPS ultraviolet photoelectron spectroscopyur ureaUra uracilUSP United States PharmacopeiaUT universal timeUTP uridine 5'-triphosphateUV ultravioletv reaction rate, specific volume, velocity, vibrational

quantum number, vicinal (as chemical descriptor)V voltV electric potential, potential energy, volumeVal valinevap vaporizationVB valence band, valence bondVCD vibrational circular dichroismVHF very high frequency

vic vicinal (on adjacent carbon atoms)VIS visible region of the spectrumvit vitreousVSEPR valence shell electron pair repulsionVSLI very large scale integrated (circuit)VUV vacuum ultravioletv/v volume per volume (volume of solute divided by

volume of solution, expressed as percent)w energy density, mass fraction, velocity, workW wattW radiant energy, statistical weight, workWAXS wide angle x-ray scatteringWb weberWe Weber numberWKB Wentzel-Kramers-Brillouin (method)wt weightw/v weight per volume (mass of solute divided by volume

of solution, generally expressed as g/100 mL)w/w weight per weight (mass of solute divided by mass of

solution, expressed as percent)x mole fractionX X unit, halogen (in chemical formula)X reactanceXAFS x-ray absorption fine structureXANES x-ray absorption near-edge structureXPES x-ray photoelectron spectroscopyXPS x-ray photoelectron spectroscopyXRD x-ray diffractionXRF x-ray fluorescenceXRS x-ray spectroscopyXyl xylosey, yr yearY admittance, Planck function, Young’s modulusyd yardz charge number (of an ion), collision frequency factorZ atomic number, compression factor, collision number,

impedance, partition function, zusammen (cisconfiguration)

ZDO zero differential overlapZPE, ZPVE zero point vibrational energyZULU Greenwich mean timeα alpha particleα absorption coefficient, degree of dissociation, electric

polarizability, expansion coefficient, fine structureconstant

β beta particleγ photonγ activity coefficient, conductivity, magnetogyric ratio,

mass concentration, ratio of heat capacities, surfacetension

Γ Gruneisin parameter, level width, surfaceconcentration

δ chemical shift, Dirac delta function, Kronecker delta,loss angle

∆ inertia defect, mass defectε emittance, Levi-Civita symbol, linear strain, molar

absorption coefficient, permittivityη overpotential, viscosityθ Bragg angle, temperature, scattering angle, surface

coverageΘ quadrupole moment


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κ compressibility, conductivity, magnetic susceptibility,molar absorption coefficient, transmission coefficient

λ absolute activity, radioactive decay constant, thermalconductivity, wavelength

Λ angular momentum, ionic conductivityµ muonµ chemical potential, electric dipole moment, electric

mobility, friction coefficient, Joule-Thompsoncoefficient, magnetic dipole moment, mobility,permeability

µF microfaradµg microgramµm micrometerµs microsecondν frequency, kinematic velocity, stoichiometric number,

wavenumberνe neutrinoπ pionΠ osmotic pressure, Peltier coefficient


ρ density, reflectance, resistivityσ electrical conductivity, cross section, normal stress,

shielding constant (NMR), Stefan-Boltzmannconstant, surface tension

τ transmittance, chemical shift, shear stress, relaxationtime

φ electrical potential, fugacity coefficient, osmoticcoefficient, quantum yield, volume fraction,wavefunction

Φ magnetic flux, potential energy, radiant power, workfunction

χ magnetic susceptibility, electronegativityχe electric susceptibilityψ wavefunctionω circular frequency, angular velocity, harmonic

vibration wavenumber, statistical weightΩ ohmΩ axial angular momentum, solid angle

scientific abbreviations and symbols

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