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Topic Review
Tapered Optical Fiber Sensor
Optical fiber sensors based on tapered optical fiber (TOF) structure have attracted a considerable amount of attention from researchers due to the advantages of simple fabrication, high stability, and diverse structures, and have great potential for applications in many fields such as physics, chemistry, and biology. Compared with conventional optical fibers, TOF with their unique structural characteristics significantly improves the sensitivity and response speed of fiber-optic sensors and broadens the application range. 
  • 260
  • 29 Jun 2023
Topic Review
Space Apps
Space Apps is annual NASA's global hackathon, first held in April 2012, and serves as innovation incubation and civic engagement program. NASA and its partners put out challenges relating to current work for which space enthusiasts around the world of all backgrounds can develop innovative solutions (which can be more than just apps!), particularly focusing on use of NASA data and promoting education. The project, formerly run by NASA's Office of the Chief Information Officer, is part of NASA's Earth Science Mission Directorate and is a part of the Open Government Initiative founded under President Barack Obama "creating an unprecedented level of openness in Government." It also fulfills the United States’ commitments to the Open Government Partnership.
  • 259
  • 08 Nov 2022
Topic Review
Conversion of Units of Temperature
This is a collection of temperature conversion formulas and comparisons among eight different temperature scales, several of which have long been obsolete.
  • 258
  • 30 Sep 2022
Topic Review
List of Unnumbered Minor Planets: 2001 S–Y
This is a partial list of unnumbered minor planets for principal designations assigned between 16 September 2001 and 31 December 2001 (S–Z).
  • 257
  • 29 Nov 2022
Topic Review
Optical Tweezers with Metasurfaces
Optical tweezers (OTs) have made significant progress, realizing the non-contact optical manipulation of target objects through the interaction between light and matter. In addition to trapping particles with the intensity gradient of the beam, a series of complex optical elements are required to properly modulate the beams to expand the operation of optical manipulation. The development of metasurfaces alleviates this problem. Due to the merits of miniaturization, planarization, multi-function, and integration of metasurfaces, these kinds of novel devices have been applied in OT systems. 
  • 256
  • 17 Aug 2023
Topic Review
Osmium-183
Osmium (76Os) has seven naturally occurring isotopes, five of which are stable: 187Os, 188Os, 189Os, 190Os, and (most abundant) 192Os. The other natural isotopes, 184Os, and 186Os, have extremely long half-life (1.12×1013 years and 2×1015 years, respectively) and for practical purposes can be considered to be stable as well. 187Os is the daughter of 187Re (half-life 4.56×1010 years) and is most often measured in an 187Os/188Os ratio. This ratio, as well as the 187Re/188Os ratio, have been used extensively in dating terrestrial as well as meteoric rocks. It has also been used to measure the intensity of continental weathering over geologic time and to fix minimum ages for stabilization of the mantle roots of continental cratons. However, the most notable application of Os in dating has been in conjunction with iridium, to analyze the layer of shocked quartz along the Cretaceous–Paleogene boundary that marks the extinction of the dinosaurs 66 million years ago. There are also 30 artificial radioisotopes, the longest-lived of which is 194Os with a half-life of six years; all others have half-lives under 94 days. There are also nine known nuclear isomers, the longest-lived of which is 191mOs with a half-life of 13.10 hours. All isotopes and nuclear isomers of osmium are either radioactive or observationally stable, meaning that they are predicted to be radioactive but no actual decay has been observed.
  • 254
  • 24 Oct 2022
Topic Review
AFM Investigation of Protein Crystals Morphology
Atomic force microscopy (AFM) enables the visualization of soft samples over a wide size range, from hundreds of micrometers up to the molecular level. The nonperturbative nature, the ability to scan in a liquid environment, and the lack of need for freezing, fixing, or staining make AFM a well-suited tool for studying fragile samples such as macromolecular crystals. The achievements of AFM underlined start from the study of crystal growth processes studying the surface morphology of protein crystals, passes through the in-depth analysis of the S-layer systems, and arrive at the introduction of the high-speed atomic force microscopy (HS-AFM) that allows the observation of molecular dynamics adsorption.
  • 252
  • 06 Sep 2023
Topic Review
Chamaeleon
Chamaeleon, a small and inconspicuous constellation in the southern celestial hemisphere, represents the chameleon, a creature known for its ability to change color and blend into its surroundings. Despite its modest size, Chamaeleon holds significance in astronomy for its proximity to the southern celestial pole and its role in studying star formation and stellar evolution.
  • 252
  • 08 Mar 2024
Topic Review
Steppe Polecat
The Steppe Polecat, scientifically known as Mustela eversmannii, is a small carnivorous mammal native to the steppes and semi-deserts of Central Asia. With a sleek body and distinctive facial markings, this elusive predator is well-adapted to its arid habitat, where it preys on rodents, birds, and insects. Despite its relatively small size, the Steppe Polecat plays a crucial role in controlling rodent populations and maintaining the balance of its ecosystem.
  • 252
  • 15 Mar 2024
Topic Review
Osmium-168
Osmium (76Os) has seven naturally occurring isotopes, five of which are stable: 187Os, 188Os, 189Os, 190Os, and (most abundant) 192Os. The other natural isotopes, 184Os, and 186Os, have extremely long half-life (1.12×1013 years and 2×1015 years, respectively) and for practical purposes can be considered to be stable as well. 187Os is the daughter of 187Re (half-life 4.56×1010 years) and is most often measured in an 187Os/188Os ratio. This ratio, as well as the 187Re/188Os ratio, have been used extensively in dating terrestrial as well as meteoric rocks. It has also been used to measure the intensity of continental weathering over geologic time and to fix minimum ages for stabilization of the mantle roots of continental cratons. However, the most notable application of Os in dating has been in conjunction with iridium, to analyze the layer of shocked quartz along the Cretaceous–Paleogene boundary that marks the extinction of the dinosaurs 66 million years ago. There are also 30 artificial radioisotopes, the longest-lived of which is 194Os with a half-life of six years; all others have half-lives under 94 days. There are also nine known nuclear isomers, the longest-lived of which is 191mOs with a half-life of 13.10 hours. All isotopes and nuclear isomers of osmium are either radioactive or observationally stable, meaning that they are predicted to be radioactive but no actual decay has been observed.
  • 252
  • 01 Nov 2022
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