Class information for:
Level 2: TIME FREQUENCY//ATOMIC CLOCKS//FREQUENCY STANDARD

Basic class information
Bar chart of Publication_year

Last years might be incomplete

Hierarchy of classes
The table includes all classes above and classes immediately below the current class.


Cluster id Level Cluster label #P
13 4 PHYSICS, PARTICLES & FIELDS//PHYSICS, NUCLEAR//OPTICS 1062565
141 3       PHYSICAL REVIEW A//OPTICS//PHYSICS, ATOMIC, MOLECULAR & CHEMICAL 66180
1640 2             TIME FREQUENCY//ATOMIC CLOCKS//FREQUENCY STANDARD 7221
2885 1                   TRAPPED IONS//TIME FREQUENCY//ION TRAP 2152
5806 1                   FREQUENCY COMB//OPTICAL FREQUENCY COMB//OPTICAL FREQUENCY METROLOGY 1602
6022 1                   OPTICAL FREQUENCY STANDARD//ATOMIC CLOCKS//LNE SYRTE 1572
15471 1                   ARC EXCELLENCE ENGN QUANTUM SYST//DIELECTRIC RESONATORS//FREQUENCY STAND METROL GRP 738
19056 1                   MEASUREMENT RUMENT//METROLOGIA//TIME TRANSFER 546
24067 1                   CESIUM BEAM FREQUENCY STANDARD//HORLOGE ATOM//ACCURACY OF FREQUENCY STANDARD 348
26864 1                   DIFFUSION TECHNOLOGY//ACL BECL2 SYSTEMS//CERNOBYL 263

Terms with highest relevance score


rank Category termType chi_square shrOfCwithTerm shrOfTermInClass termInClass
1 TIME FREQUENCY address 568489 3% 53% 247
2 ATOMIC CLOCKS authKW 202797 1% 51% 92
3 FREQUENCY STANDARD authKW 166843 1% 65% 59
4 OPTICAL CLOCK authKW 123504 1% 75% 38
5 LNE SYRTE address 108406 1% 42% 59
6 OPTICAL FREQUENCY STANDARD authKW 105130 1% 54% 45
7 FREQUENCY STABILITY authKW 80429 1% 28% 66
8 OPTICAL FREQUENCY COMB authKW 79847 1% 31% 59
9 TIME TRANSFER authKW 76201 0% 56% 31
10 OPTICS WoSSC 74924 43% 1% 3071

Web of Science journal categories


chi_square_rank Category chi_square shrOfCwithTerm shrOfTermInClass termInClass
1 Optics 74924 43% 1% 3071
2 Physics, Atomic, Molecular & Chemical 14461 18% 0% 1330
3 Physics, Multidisciplinary 11857 20% 0% 1419
4 Instruments & Instrumentation 9075 12% 0% 854
5 Physics, Applied 6442 21% 0% 1545
6 Engineering, Electrical & Electronic 4612 17% 0% 1227
7 Acoustics 3104 4% 0% 305
8 Engineering, General 124 2% 0% 112
9 Telecommunications 94 2% 0% 119
10 Spectroscopy 21 1% 0% 84

Address terms


chi_square_rank term chi_square shrOfCwithTerm shrOfTermInClass termInClass
1 TIME FREQUENCY 568489 3% 53% 247
2 LNE SYRTE 108406 1% 42% 59
3 ATOM FREQUENCY STAND 58942 0% 48% 28
4 ARC EXCELLENCE ENGN QUANTUM SYST 54185 0% 37% 34
5 ULTRACOLD ATOMS 50302 0% 38% 30
6 INNOVAT SPACE TIME PROJECT 50294 0% 82% 14
7 FREQUENCY TIME GRP 44870 0% 86% 12
8 METROL ESSAIS SYST REFERENCES TEMPS ES 43988 0% 92% 11
9 JILA 41821 2% 7% 141
10 QUANTENOPT QUANTENINFORMAT 39190 1% 17% 53

Journals


chi_square_rank term chi_square shrOfCwithTerm shrOfTermInClass termInClass
1 METROLOGIA 74912 3% 8% 221
2 IEEE TRANSACTIONS ON ULTRASONICS FERROELECTRICS AND FREQUENCY CONTROL 70016 4% 5% 302
3 PHYSICAL REVIEW A 52289 13% 1% 908
4 APPLIED PHYSICS B-LASERS AND OPTICS 40237 4% 3% 268
5 IEEE TRANSACTIONS ON INSTRUMENTATION AND MEASUREMENT 39088 4% 3% 287
6 OPTICS LETTERS 30821 6% 2% 465
7 OPTICS EXPRESS 17861 5% 1% 387
8 PHYSICAL REVIEW LETTERS 9455 7% 1% 471
9 NEW JOURNAL OF PHYSICS 8691 2% 1% 137
10 NATURE PHOTONICS 5305 1% 3% 37

Author Key Words


chi_square_rank term chi_square shrOfCwithTerm shrOfTermInClass termInClass LCSH search Wikipedia search
1 ATOMIC CLOCKS 202797 1% 51% 92 Search ATOMIC+CLOCKS Search ATOMIC+CLOCKS
2 FREQUENCY STANDARD 166843 1% 65% 59 Search FREQUENCY+STANDARD Search FREQUENCY+STANDARD
3 OPTICAL CLOCK 123504 1% 75% 38 Search OPTICAL+CLOCK Search OPTICAL+CLOCK
4 OPTICAL FREQUENCY STANDARD 105130 1% 54% 45 Search OPTICAL+FREQUENCY+STANDARD Search OPTICAL+FREQUENCY+STANDARD
5 FREQUENCY STABILITY 80429 1% 28% 66 Search FREQUENCY+STABILITY Search FREQUENCY+STABILITY
6 OPTICAL FREQUENCY COMB 79847 1% 31% 59 Search OPTICAL+FREQUENCY+COMB Search OPTICAL+FREQUENCY+COMB
7 TIME TRANSFER 76201 0% 56% 31 Search TIME+TRANSFER Search TIME+TRANSFER
8 FREQUENCY COMB 73953 1% 39% 43 Search FREQUENCY+COMB Search FREQUENCY+COMB
9 LASER COOLING 72480 1% 20% 82 Search LASER+COOLING Search LASER+COOLING
10 TRAPPED IONS 57744 1% 25% 54 Search TRAPPED+IONS Search TRAPPED+IONS

Core articles
The table includes core articles in the class. The following variables is taken into account for the relevance score of an article in a cluster c:
(1) Number of references referring to publications in the class.
(2) Share of total number of active references referring to publications in the class.
(3) Age of the article. New articles get higher score than old articles.
(4) Citation rate, normalized to year.

Classes with closest relation at Level 2


rank cluster_id2 link
1 1957 HYPERPOLARIZED GAS//HYPERPOLARIZED//ATOMIC MAGNETOMETER
2 73 PHYSICAL REVIEW A//BOSE EINSTEIN CONDENSATE//BOSE EINSTEIN CONDENSATION
3 1053 JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS//PHYSICA SCRIPTA//ATOMIC DATA AND NUCLEAR DATA TABLES
4 3143 ETHYLBENZENE DEHYDROGENATION//RYDBERG ATOMS//ETHYLBENZENE
5 1213 OPTICS//OPTICS LETTERS//CHIRPED PULSE AMPLIFICATION
6 1782 PHOTONIC CRYSTAL FIBER//SUPERCONTINUUM GENERATION//CONFINEMENT LOSS
7 2368 QUANTUM WALK//QUANTUM ALGORITHMS//QUANTUM COMPUTATION
8 1258 ANTIHYDROGEN//PHYSICAL REVIEW A//POSITRONIUM
9 3 PHYSICAL REVIEW A//ENTANGLEMENT//QUANTUM INFORMATION PROCESSING
10 2389 WHISPERING GALLERY MODES//MICRODISK//OPTOFLUIDICS

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