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相关概念视频

Cationic Chain-Growth Polymerization: Mechanism00:57

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The cationic polymerization mechanism consists of three steps: initiation, propagation, and termination. In the initiation step of the polymerization process, the π bond of a monomer gets protonated by the Lewis acid catalyst, which is formed from boron trifluoride and water. The protonation of the π bond generates a carbocation stabilized by the electron‐donating group. In the propagation step, the π bond of the second monomer acts as a nucleophile and attacks the...
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Initiation of Translation02:33

Initiation of Translation

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Initiating translation is complex because it involves multiple molecules. Initiator tRNA, ribosomal subunits, and eukaryotic initiation factors (eIFs) are all required to assemble on the initiation codon of mRNA. This process consists of several steps that are mediated by different eIFs.
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Initiation is the first step of transcription in eukaryotes. Prokaryotic RNA Polymerase (RNAP) can bind to the template DNA and start transcribing. On the other hand, transcription in eukaryotes requires additional proteins, called transcription factors, to first bind to the promoter region in the DNA template. This binding helps recruit the specific RNAP that can assemble on the DNA and start transcription.
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Components of Stress01:23

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Stress analysis under multiple loading conditions is intricate, necessitating a comprehensive grasp of normal and shearing stresses. Consider a small cube at point O, subjected to stress on all six faces, visible or not. Normal stress components σx, σy, σz act perpendicularly to the x, y, and z axes. Shearing stress components τxy and τxz are exerted on faces perpendicular to these axes.
Interestingly, the hidden cube faces also experience these stresses, equal and...
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Components of Language01:24

Components of Language

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Language, whether spoken, signed, or written, consists of specific components: lexicon and grammar. The lexicon is the vocabulary of a language, comprising its words. Grammar is the set of rules used to convey meaning through the lexicon. For example, English grammar adds “-ed” to most verbs to indicate past tense. Words are formed by combining phonemes, which are the basic sound units of a language. Different languages have different sets of phonemes (e.g., “ah” vs.
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Applications of the Single-probe: Mass Spectrometry Imaging and Single Cell Analysis under Ambient Conditions
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控制的阴离子聚合:在环境条件下单元启动

Veronika Kottisch1, Jacob O'Leary1, Quentin Michaudel1

  • 1Cornell University , Ithaca , New York 14853 , United States.

Journal of the American Chemical Society
|June 27, 2019
PubMed
概括
此摘要是机器生成的。

这项研究引入了五碳甲基环二烯 (PCCP) 作为一种新的化聚合剂启动剂. 它可以在环境条件下进行受控的乙烯基乙烯聚合,并具有高链端真实性,简化了聚合物合成.

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科学领域:

  • 聚合物化学
  • 有机合成
  • 大分子科学

背景情况:

  • 阴离子聚合提供精确的宏分子合成,但需要严格的条件,如低温和无水环境.
  • 对杂质的敏感性往往需要广泛的试剂净化,使该过程复杂化.

研究的目的:

  • 开发一种简单且强大的聚合离子方法.
  • 在环境条件下实现乙烯基乙烯的受控聚合.
  • 在没有严格的单体净化的情况下保持高链端保真性.

主要方法:

  • 作为单个组件启动有机酸,使用了五碳甲基cyclopentadiene (PCCP).
  • 研究了多种类型的乙烯基乙烯的聚合.
  • 用于链末端的功能性核友.

主要成果:

  • 在环境条件下使用PCCP实现了对乙烯基乙烯的控制聚合.
  • 证明了出色的链末忠实性,即使是未经净化的单体.
  • 通过核性终结成功实现高产量的聚合物链末端.

结论:

  • PCCP作为一个有效的启动器,用于维尼尔的环境阴离子聚合.
  • 一个拟议的紧密离子复合机制解释了观察到的生命特征和高保真度.
  • 这种方法提供了对受控聚合物合成和功能化的实用方法.