Determination of optimum Si excess concentration in Er-doped Si-rich SiO2 for optical amplification at 1.54 μm

2010 ◽  
Vol 97 (20) ◽  
pp. 201107 ◽  
Author(s):  
Oleksandr Savchyn ◽  
Kevin R. Coffey ◽  
Pieter G. Kik
Keyword(s):  
Optical Amplification ◽  
Excess Concentration ◽  
Er Doped

Optical amplification and electroluminescence at 1.54 μm in Er-doped zinc silicate germanate on silicon

2004 ◽  
Vol 84 (9) ◽  
pp. 1462-1464 ◽  
Author(s):  
C. C. Baker ◽  
J. Heikenfeld ◽  
Z. Yu ◽  
A. J. Steckl
Keyword(s):  
Zinc Silicate ◽  
Optical Amplification ◽  
Er Doped

New Er-doped phosphate glass for ion-exchange active waveguides: accurate determination of the refractive index

2000 ◽  
Vol 14 (4) ◽  
pp. 291-296 ◽  
Author(s):  
R Ramponi ◽  
R Osellame ◽  
M Marangoni ◽  
G Sorbello ◽  
P Laporta ◽  
...  
Keyword(s):  
Refractive Index ◽  
Ion Exchange ◽  
Phosphate Glass ◽  
Accurate Determination ◽  
Er Doped

scholarly journals THE MODIFIED MODEL OF DIFFUSION FLOW OF MULTICOMPONENT COMBUSTIBLE GAS

2015 ◽  
pp. 93-97
Author(s):  
R. A. Shtykov
Keyword(s):  
Gas Diffusion ◽  
Diffusion Combustion ◽  
Gas Temperature ◽  
Active Components ◽  
Simple Modification ◽  
Modified Model ◽  
Total Enthalpy ◽  
Combustible Gas ◽  
Excess Concentration

The model of gas diffusion combustion developed by Zeldovich Ya.B., despite of the fairly satisfactory agree-ment of the obtained data with the experiment shows a non-universality and a large volume of the algorithm for de-termining the concentrations of the components when a number of active components and their composition change. In this regard, it became necessary to develop a different, simple modification of Zeldovich’s model, which would lead to the least number of operations for determination of the gas temperature and density at known values of rela-tively excess concentration and total enthalpy.

scholarly journals New insights into the enzymatic mechanism of human chitotriosidase (CHIT1) catalytic domain by atomic resolution X-ray diffraction and hybrid QM/MM

2015 ◽  
Vol 71 (7) ◽  
pp. 1455-1470 ◽  
Author(s):  
Firas Fadel ◽  
Yuguang Zhao ◽  
Raul Cachau ◽  
Alexandra Cousido-Siah ◽  
Francesc X. Ruiz ◽  
...  
Keyword(s):  
Catalytic Mechanism ◽  
Catalytic Domain ◽  
Glycosyl Hydrolase ◽  
Catalytic Triad ◽  
X Ray Diffraction ◽  
Protonation State ◽  
Enzymatic Mechanism ◽  
Excess Concentration ◽  
Hydrolase Family

Chitotriosidase (CHIT1) is a human chitinase belonging to the highly conserved glycosyl hydrolase family 18 (GH18). GH18 enzymes hydrolyze chitin, anN-acetylglucosamine polymer synthesized by lower organisms for structural purposes. Recently, CHIT1 has attracted attention owing to its upregulation in immune-system disorders and as a marker of Gaucher disease. The 39 kDa catalytic domain shows a conserved cluster of three acidic residues, Glu140, Asp138 and Asp136, involved in the hydrolysis reaction. Under an excess concentration of substrate, CHIT1 and other homologues perform an additional activity, transglycosylation. To understand the catalytic mechanism of GH18 chitinases and the dual enzymatic activity, the structure and mechanism of CHIT1 were analyzed in detail. The resolution of the crystals of the catalytic domain was improved from 1.65 Å (PDB entry 1waw) to 0.95–1.10 Å for the apo and pseudo-apo forms and the complex with chitobiose, allowing the determination of the protonation states within the active site. This information was extended by hybrid quantum mechanics/molecular mechanics (QM/MM) calculations. The results suggest a new mechanism involving changes in the conformation and protonation state of the catalytic triad, as well as a new role for Tyr27, providing new insights into the hydrolysis and transglycosylation activities.

Er-doped Si nanoclusters waveguides longitudinally pumped by broad area lasers for optical amplification

2009 ◽  
Author(s):  
V. Donzella ◽  
V. Toccafondo ◽  
S. Faralli ◽  
F. Di Pasquale ◽  
A. Pitanti ◽  
...  
Keyword(s):  
Broad Area ◽  
Optical Amplification ◽  
Er Doped ◽  
Broad Area Lasers

Concentration effect on optical amplification characteristics of Er-doped silica single-mode fibers

1990 ◽  
Vol 2 (1) ◽  
pp. 43-45 ◽  
Author(s):  
M. Shimizu ◽  
M. Yamada ◽  
M. Horiguchi ◽  
E. Sugita
Keyword(s):  
Single Mode ◽  
Concentration Effect ◽  
Optical Amplification ◽  
Er Doped
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