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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. 
  • 219
  • 29 Jun 2023
Topic Review
Tanpopo (Mission)
The Tanpopo mission is an orbital astrobiology experiment investigating the potential interplanetary transfer of life, organic compounds, and possible terrestrial particles in the low Earth orbit. The purpose is to assess the panspermia hypothesis and the possibility of natural interplanetary transport of microbial life as well as prebiotic organic compounds. The collection and exposure phase took place from May 2015 through February 2018 utilizing the Exposed Facility located on the exterior of Kibo, the Japanese Experimental Module of the International Space Station. The mission, designed and performed by Japan, used ultra-low density silica gel (aerogel) to collect cosmic dust by, which is being analyzed for amino acid-related compounds and microorganisms following their return to Earth. The last samples were retrieved in February 2018 and analyses are ongoing. The principal investigator is Akihiko Yamagishi, who heads a team of researchers from 26 universities and institutions in Japan, including JAXA.
  • 426
  • 14 Oct 2022
Topic Review
Tandem Mass Spectrometry
Tandem mass spectrometry, also known as MS/MS or MS2, involves multiple steps of mass spectrometry selection, with some form of fragmentation occurring in between the stages. In a tandem mass spectrometer, ions are formed in the ion source and separated by mass-to-charge ratio in the first stage of mass spectrometry (MS1). Ions of a particular mass-to-charge ratio (precursor ions) are selected and fragment ions (product ions) are created by collision-induced dissociation, ion-molecule reaction, photodissociation, or other process. The resulting ions are then separated and detected in a second stage of mass spectrometry (MS2).
  • 6.2K
  • 19 Oct 2022
Topic Review
Synchrotron Light Source
A synchrotron light source is a source of electromagnetic radiation (EM) usually produced by a storage ring, for scientific and technical purposes. First observed in synchrotrons, synchrotron light is now produced by storage rings and other specialized particle accelerators, typically accelerating electrons. Once the high-energy electron beam has been generated, it is directed into auxiliary components such as bending magnets and insertion devices (undulators or wigglers) in storage rings and free electron lasers. These supply the strong magnetic fields perpendicular to the beam which are needed to convert high energy electrons into photons. The major applications of synchrotron light are in condensed matter physics, materials science, biology and medicine. A large fraction of experiments using synchrotron light involve probing the structure of matter from the sub-nanometer level of electronic structure to the micrometer and millimeter level important in medical imaging. An example of a practical industrial application is the manufacturing of microstructures by the LIGA process.
  • 541
  • 11 Oct 2022
Topic Review
SWCNTs in Nanoelectronics
The unique tailored electronic properties of single-walled carbon nanotubes (SWCNTs) render them promising platforms for nanoelectronics applications.
  • 676
  • 09 Nov 2021
Topic Review
SWCNTs in Magnetic Recording
Applications in magnet-recording devices rely on the combination and emergence of unique properties of single-walled carbon nanotubes (SWCNTs) and encapsulated materials. The entry “SWCNTs in magnetic recording” focuses on applications of filled SWCNTs in magnetic recording.
  • 603
  • 11 Nov 2021
Topic Review
Surface-Extended X-Ray Absorption Fine Structure
Surface-extended X-ray absorption fine structure (SEXAFS) is the surface-sensitive equivalent of the EXAFS technique. This technique involves the illumination of the sample by high-intensity X-ray beams from a synchrotron and monitoring their photoabsorption by detecting in the intensity of Auger electrons as a function of the incident photon energy. Surface sensitivity is achieved by the interpretation of data depending on the intensity of the Auger electrons (which have an escape depth of ~1–2 nm) instead of looking at the relative absorption of the X-rays as in the parent method, EXAFS. The photon energies are tuned through the characteristic energy for the onset of core level excitation for surface atoms. The core holes thus created can then be filled by nonradiative decay of a higher-lying electron and communication of energy to yet another electron, which can then escape from the surface (Auger emission). The photoabsorption can therefore be monitored by direct detection of these Auger electrons to the total photoelectron yield. The absorption coefficient versus incident photon energy contains oscillations which are due to the interference of the backscattered Auger electrons with the outward propagating waves. The period of this oscillations depends on the type of the backscattering atom and its distance from the central atom. Thus, this technique enables the investigation of interatomic distances for adsorbates and their coordination chemistry. This technique benefits from long range order not being required, which sometimes becomes a limitation in the other conventional techniques like LEED (about 10 nm). This method also largely eliminates the background from the signal. It also benefits because it can probe different species in the sample by just tuning the X-ray photon energy to the absorption edge of that species. Joachim Stöhr played a major role in the initial development of this technique.
  • 497
  • 24 Oct 2022
Topic Review
Surface- and Tip-Enhanced Raman Scattering
Surface-enhanced Raman scattering (SERS) is of growing interest for a wide range of applications, especially for biomedical analysis, thanks to its sensitivity, specificity, and multiplexing capabilities. A crucial role for successful applications of SERS is played by the development of reproducible, efficient, and facile procedures for the fabrication of metal nanostructures (SERS substrates). Even more challenging is to extend the fabrication techniques of plasmonic nano-textures to atomic force microscope (AFM) probes to carry out tip-enhanced Raman spectroscopy (TERS) experiments, in which spatial resolution below the diffraction limit is added to the peculiarities of SERS.
  • 135
  • 23 Nov 2023
Topic Review
Surface Plasmon Coupled Emission Technology
Novel nano-engineering protocols have been actively synergized with fluorescence spectroscopic techniques to yield higher intensity from radiating dipoles, through the process termed plasmon-enhanced fluorescence (PEF). Consequently, the limit of detection of analytes of interest has been dramatically improvised on account of higher sensitivity rendered by augmented fluorescence signals. Metallic thin films sustaining surface plasmon polaritons (SPPs) have been creatively hybridized with such PEF platforms to realize a substantial upsurge in the global collection efficiency in a judicious technology termed surface plasmon-coupled emission (SPCE). This Editorial Review by Dr. Seemesh Bhaskar, University of Illinois Urbana-Champaign, provides a spotlight on the latest developments in SPCE substrate engineering to the broad audience of photo-plasmonics, spectroscopy, micro- & nanotechnology, life sciences, thin films and point-of-care diagnostics.
  • 551
  • 13 Mar 2023
Topic Review
Surface Chemistry of Paper
The surface chemistry of paper is responsible for many important paper properties, such as gloss, waterproofing, and printability. Many components are used in the paper-making process that affect the surface.
  • 565
  • 11 Oct 2022
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