Concluding remarks

1967 ◽  
Vol 167 (1009) ◽  
pp. 448-448 ◽  
Keyword(s):  
Dielectric Constant ◽  
Catalytic Activity ◽  
Active Sites ◽  
Low Dielectric Constant ◽  
Side Chains ◽  
Polar Medium ◽  
Active Centre ◽  
Low Dielectric ◽  
Globin Chains ◽  
First Time

For the first time we have been able to interpret the catalytic activity of an enzyme in stereochemical terms. It seems rash to generalize from the structure of one enzyme, but we may broaden our base by elevating myoglobin and haemoglobin to the rank of honorary enzymes, as Monod has suggested, and call the haem groups their active sites. What these three proteins have in common is the distribution of polar and nonpolar side chains; the interior of the lysozyme as well as that of the globin chains is made up largely of hydrocarbons, providing a medium of low dielectric constant. In each case the active centre lies in a pocket formed by this non-polar medium, and the pocket contains some polar residues which are essential for activity.

scholarly journals Biorenewable rosin derived benzocyclobutene resin: a thermosetting material with good hydrophobicity and low dielectric constant

RSC Advances ◽  
2019 ◽  
Vol 9 (51) ◽  
pp. 29788-29795
Author(s):  
Fei Fu ◽  
Dan Wang ◽  
Minggui Shen ◽  
Shibin Shang ◽  
Zhanqian Song ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Low Dielectric Constant ◽  
Low Dielectric ◽  
First Time

The rosin structure was introduced into benzocyclobutene resin for the first time, and the thermosetting material with good hydrophobicity and low dielectric constant was prepared.

Concluding remarks

1970 ◽  
Vol 257 (813) ◽  
pp. 265-266 ◽  
Keyword(s):  
Dielectric Constant ◽  
Free Energy ◽  
Catalytic Activity ◽  
Active Site ◽  
Royal Society ◽  
Low Dielectric Constant ◽  
Free Charge ◽  
Low Dielectric ◽  
Activity Of Enzymes

At the conclusion of the Royal Society discussion on lysozyme a little over two years ago, I had to follow Monod and elevate myoglobin and haemoglobin to the rank of honorary enzymes so as to draw my generalizations from three structures rather than a single one. I then suggested that the powerful catalytic activity of enzymes was due to the medium of low dielectric constant provided by their non-polar interior, which allowed strong electrical interactions to take place between the active site and the substrate. The structures of the six additional enzymes which have since been solved have confirmed this view, but they have also shown that it should be broadened. It appears that in the medium of low dielectric constant a free charge introduces a large free energy. To regain stability two alternative devices are open to the enzyme: (1) to compensate the charge internally; (2) to design a system of bonds which transfers the charge to the surface.

A new glass-forming molecule having a fluorene skeleton: synthesis and conversion to the polymer with a low dielectric constant, high hydrophobicity and thermostability

2016 ◽  
Vol 7 (38) ◽  
pp. 5925-5929 ◽  
Author(s):  
Yuanqiang Wang ◽  
Jiajia Wang ◽  
Kaikai Jin ◽  
Jing Sun ◽  
Qiang Fang
Keyword(s):  
Dielectric Constant ◽  
Low Dielectric Constant ◽  
Side Chains ◽  
Glass Forming ◽  
Low Dielectric ◽  
Trifluorovinyl Ether

A new glass-forming molecule having a fluorene skeleton and thermally cross-linkable trifluorovinyl-ether side chains is reported here.

Structire, Properties, and Process Characteristics of Low-K Materials Prepared by PECVD

1999 ◽  
Vol 565 ◽  
Author(s):  
Y. Shimogaki ◽  
S. W. Lim ◽  
E. G. Loh ◽  
Y. Nakano ◽  
K. Tada ◽  
...  
Keyword(s):  
Growth Rate ◽  
Dielectric Constant ◽  
Gas Flow ◽  
Structural Changes ◽  
Silicon Oxide ◽  
Reactive Species ◽  
Low Dielectric Constant ◽  
Low Dielectric ◽  
Step Coverage ◽  
Low K

AbstractLow dielectric constant F-doped silicon oxide films (SiO:F) can be prepared by adding fluorine source, like as CF4 to the conventional PECVD processes. We could obtain SiO:F films with dielectric constant as low as 2.6 from the reaction mixture of SiH4/N2 O/CF4. The structural changes of the oxides were sensitively detected by Raman spectroscopy. The three-fold ring and network structure of the silicon oxides were selectively decreased by adding fluorine into the film. These structural changes contribute to the decrease ionic polarization of the film, but it was not the major factor for the low dielectric constant. The addition of fluorine was very effective to eliminate the Si-OH in the film and the disappearance of the Si-OH was the key factor to obtain low dielectric constant. A kinetic analysis of the process was also performed to investigate the reaction mechanism. We focused on the effect of gas flow rate, i.e. the residence time of the precursors in the reactor, on growth rate and step coverage of SiO:F films. It revealed that there exists two species to form SiO:F films. One is the reactive species which contributes to increase the growth rate and the other one is the less reactive species which contributes to have uniform step coverage. The same approach was made on the PECVD process to produce low-k C:F films from C2F4, and we found ionic species is the main precursor to form C:F films.

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