Jove
Visualize
Contact Us
JoVE
x logofacebook logolinkedin logoyoutube logo
ABOUT JoVE
OverviewLeadershipBlogJoVE Help Center
AUTHORS
Publishing ProcessEditorial BoardScope & PoliciesPeer ReviewFAQSubmit
LIBRARIANS
TestimonialsSubscriptionsAccessResourcesLibrary Advisory BoardFAQ
RESEARCH
JoVE JournalMethods CollectionsJoVE Encyclopedia of ExperimentsArchive
EDUCATION
JoVE CoreJoVE BusinessJoVE Science EducationJoVE Lab ManualFaculty Resource CenterFaculty Site
Terms & Conditions of Use
Privacy Policy
Policies

Related Concept Videos

Insensitive Nuclei Enhanced by Polarization Transfer (INEPT)01:15

Insensitive Nuclei Enhanced by Polarization Transfer (INEPT)

1.1K
Insensitive Nuclei Enhanced by Polarization Transfer (INEPT) is an advanced Nuclear Magnetic Resonance (NMR) technique specifically designed to detect and enhance the signals of low-abundance nuclei, such as carbon-13 and nitrogen-15, in small molecules. The fundamental principle behind INEPT is the transfer of polarization from a more abundant and highly polarizable nucleus, typically hydrogen-1, to the low-abundance nucleus of interest. This process effectively boosts the NMR signal of the...
1.1K
meta-Directing Deactivators: –NO2, –CN, –CHO, –⁠CO2R, –COR, –CO2H01:13

meta-Directing Deactivators: –NO2, –CN, –CHO, –⁠CO2R, –COR, –CO2H

6.7K
All meta-directing substituents are deactivating groups. These substituents withdraw electrons from the aromatic ring, making the ring less reactive toward electrophilic substitution. For example, the nitration of nitrobenzene is 100,000 times slower than that of benzene because of the deactivating effect of the nitro group. The first step in an electrophilic aromatic substitution is the addition of an electrophile to form a resonance-stabilized carbocation. The energy diagrams for...
6.7K
2° Amines to N-Nitrosamines: Reaction with NaNO201:20

2° Amines to N-Nitrosamines: Reaction with NaNO2

5.5K
Secondary amines react with nitrous acid to form N-nitrosamines, as depicted in Figure 1. Nitrous acid, a weak and unstable acid, is formed in situ from an aqueous solution of sodium nitrite and strong acids, such as hydrochloric acid or sulfuric acid, in cold conditions. In the presence of an acid, the nitrous acid gets protonated. The subsequent loss of water results in the formation of the electrophile known as nitrosonium ion.
5.5K
SN2 Reaction: Kinetics02:14

SN2 Reaction: Kinetics

10.3K
Kinetic Studies and Significance
In a chemical reaction, a relationship exists between the concentration of reactants and the rate at which the reaction proceeds. The study to measure this relationship is known as the kinetics of a chemical reaction. Kinetic studies are used to deduce the rate law of a chemical reaction, which provides information about the species involved during the transition state of the rate-determining step. Thus, kinetic studies help to derive the mechanism of a...
10.3K
SN2 Reaction: Mechanism02:27

SN2 Reaction: Mechanism

17.5K
The kinetic studies of SN2 reactions suggest an essential feature of its mechanism: it is a single-step process without intermediates. Here, both the nucleophile and the substrate participate in the rate-determining step.
The presence of the more electronegative halogen in the substrate creates a polarized carbon-halide bond. The halide pulls the electron cloud generating an electrophilic center at the carbon atom. Thus, the carbon atom carries a partial positive charge while the halide has a...
17.5K
SN2 Reaction: Transition State02:26

SN2 Reaction: Transition State

12.0K
An SN2 reaction of an alkyl halide is a single-step process in which bond formation between the nucleophile and the substrate and bond breaking between the substrate and the halide occurs simultaneously through a transition state without forming an intermediate.
When the nucleophile approaches the electrophilic carbon with its lone pairs, the halide acts as a leaving group and moves away with the electron-pair bonded to the carbon. Dotted partial bonds represent the bonds being formed or broken...
12.0K

You might also read

Related Articles

Articles linked to this work by shared authors, journal, and citation graph.

Sort by
Same author

Microglia suppress Müller cell FGF1 and contribute to retinal ganglion cell degeneration in glaucoma.

Experimental eye research·2026
Same author

Room-Temperature Quasi-CW Random Lasing in a Tin-Perovskite Ultrathin Film.

The journal of physical chemistry letters·2026
Same author

Evidence architecture of glaucoma-related biomaterials reveals an uneven transition toward smart materials, additive manufacturing, and functional tissue engineering.

Frontiers in bioengineering and biotechnology·2026
Same author

Wind energy-driven rabbit hair TENG for railway detection.

iScience·2026
Same author

Mechano-optically co-designed highly-scalable silicon photonic MEMS switches with quasi-buckling-free 2 × 2 horizontal adiabatic directional couplers.

Microsystems & nanoengineering·2026
Same author

Ultraviolet-C to mid-infrared supercontinuum generation in periodically poled lithium tantalate waveguides.

Light, science & applications·2026

Related Experiment Video

Updated: Feb 9, 2026

Imaging Intermediate Filaments and Microtubules with 2-dimensional Direct Stochastic Optical Reconstruction Microscopy
14:23

Imaging Intermediate Filaments and Microtubules with 2-dimensional Direct Stochastic Optical Reconstruction Microscopy

Published on: March 6, 2018

11.4K

Polarization-insensitive 2 × 2 thermo-optic Mach-Zehnder switch on silicon.

Shipeng Wang, Daoxin Dai

    Optics Letters
    |June 2, 2018
    PubMed
    Summary

    This study presents a polarization-insensitive silicon thermo-optic Mach-Zehnder switch (MZS) using silicon-on-insulator (SOI) waveguides. The device achieves excellent extinction ratios for both TM and TE polarizations.

    Area of Science:

    • Photonics
    • Optical Engineering
    • Materials Science

    Background:

    • Thermo-optic Mach-Zehnder switches (MZS) are crucial for optical communication networks.
    • Achieving polarization-insensitivity in silicon photonic devices remains a significant challenge.
    • Silicon-on-insulator (SOI) technology offers a promising platform for integrated photonics.

    Purpose of the Study:

    • To propose and experimentally demonstrate a polarization-insensitive 2x2 thermo-optic Mach-Zehnder switch (MZS).
    • To utilize silicon-on-insulator (SOI) nanophotonic waveguides for enhanced device performance.
    • To optimize MZS design for insensitivity to optical signal polarization.

    Main Methods:

    • Design of polarization-insensitive 2x2 3 dB multimode interference (MMI) couplers by optimal core width selection.

    More Related Videos

    Measurement of Quantum Interference in a Silicon Ring Resonator Photon Source
    12:19

    Measurement of Quantum Interference in a Silicon Ring Resonator Photon Source

    Published on: April 4, 2017

    8.9K
    Use of Enzymatic Biosensors to Quantify Endogenous ATP or H2O2 in the Kidney
    10:00

    Use of Enzymatic Biosensors to Quantify Endogenous ATP or H2O2 in the Kidney

    Published on: October 12, 2015

    12.3K

    Related Experiment Videos

    Last Updated: Feb 9, 2026

    Imaging Intermediate Filaments and Microtubules with 2-dimensional Direct Stochastic Optical Reconstruction Microscopy
    14:23

    Imaging Intermediate Filaments and Microtubules with 2-dimensional Direct Stochastic Optical Reconstruction Microscopy

    Published on: March 6, 2018

    11.4K
    Measurement of Quantum Interference in a Silicon Ring Resonator Photon Source
    12:19

    Measurement of Quantum Interference in a Silicon Ring Resonator Photon Source

    Published on: April 4, 2017

    8.9K
    Use of Enzymatic Biosensors to Quantify Endogenous ATP or H2O2 in the Kidney
    10:00

    Use of Enzymatic Biosensors to Quantify Endogenous ATP or H2O2 in the Kidney

    Published on: October 12, 2015

    12.3K
  • Utilizing square SOI nanophotonic waveguides (340 nm x 340 nm) for polarization-insensitive phase shift.
  • Experimental fabrication and characterization of the silicon MZS in the C-band (1530–1565 nm).

    • Main Results:

    • Demonstrated a polarization-insensitive 2x2 thermo-optic Mach-Zehnder switch (MZS) on silicon.
    • Achieved excess loss between 1–4 dB for the fabricated silicon MZS.
    • Obtained an extinction ratio greater than 20 dB for both TM and TE polarizations in the C-band.

    Conclusions:

    • The proposed SOI-based MZS design effectively achieves polarization-insensitivity.
    • The device exhibits high performance metrics suitable for optical switching applications.
    • This work contributes to the development of robust silicon photonic integrated circuits.