Designing Stability into Thermally Reactive Plumbylenes

2018 ◽  
Author(s):  
Goran Bacic ◽  
David Zanders ◽  
Anjana Devi ◽  
Sean Barry
Keyword(s):  
Structural Analysis ◽  
Vapour Pressure ◽  
Room Temperature ◽  
Vapour Deposition ◽  
Thermal Characterization ◽  
Oxidative Cleavage ◽  
High Yield ◽  
Thermal Window ◽  
The Stability

We complete the picture of thermally stable and volatile <i>N-</i>heterocyclic metallylenes with the synthesis, structural analysis, and thermal characterization of <i>rac</i>-<i>N</i><sup>2</sup>,<i>N</i><sup>3</sup>-di-<i>tert</i>-butylbutane-2,3-diamido lead(II) (<b>1Pb</b>). Transamination of bis[bis(trimethylsilyl)amido] lead(II) with the free diamino ligand yields <b>1Pb</b> in high yield, whereas salt-metathesis leads to oxidative cleavage of the butane backbone and production of acetaldehyde-<i>tert-</i>butylimine. <b>1Pb</b> itself undergoes [2+2+1] cycloreversion at 150 °C to the same imine, but with a vapour pressure of 1 Torr at 94 °C a wide thermal window is available for use as a vapour deposition precursor.<div><br></div><div>We contrast this with the the extreme instability of its sisters <i>N</i><sup>2</sup>,<i>N</i><sup>3</sup>-di-<i>tert</i>-butylethane-2,3-diamido lead(II) (<b>2Pb</b>) and <i>N</i><sup>2</sup>,<i>N</i><sup>3</sup>-di-<i>tert</i>-butylethylene-2,3-diamido lead(II) (<b>3Pb</b>), which both reductively eliminate Pb(0) at or below room temperature. This is also in start contrast to the stability of the lighter Si, Ge and Sn congeners.</div>

Designing Stability into Thermally Reactive Plumbylenes

2018 ◽  
Author(s):  
Goran Bacic ◽  
David Zanders ◽  
Anjana Devi ◽  
Sean Barry
Keyword(s):  
Structural Analysis ◽  
Vapour Pressure ◽  
Room Temperature ◽  
Vapour Deposition ◽  
Thermal Characterization ◽  
Oxidative Cleavage ◽  
High Yield ◽  
Thermal Window ◽  
The Stability

We complete the picture of thermally stable and volatile <i>N-</i>heterocyclic metallylenes with the synthesis, structural analysis, and thermal characterization of <i>rac</i>-<i>N</i><sup>2</sup>,<i>N</i><sup>3</sup>-di-<i>tert</i>-butylbutane-2,3-diamido lead(II) (<b>1Pb</b>). Transamination of bis[bis(trimethylsilyl)amido] lead(II) with the free diamino ligand yields <b>1Pb</b> in high yield, whereas salt-metathesis leads to oxidative cleavage of the butane backbone and production of acetaldehyde-<i>tert-</i>butylimine. <b>1Pb</b> itself undergoes [2+2+1] cycloreversion at 150 °C to the same imine, but with a vapour pressure of 1 Torr at 94 °C a wide thermal window is available for use as a vapour deposition precursor.<div><br></div><div>We contrast this with the the extreme instability of its sisters <i>N</i><sup>2</sup>,<i>N</i><sup>3</sup>-di-<i>tert</i>-butylethane-2,3-diamido lead(II) (<b>2Pb</b>) and <i>N</i><sup>2</sup>,<i>N</i><sup>3</sup>-di-<i>tert</i>-butylethylene-2,3-diamido lead(II) (<b>3Pb</b>), which both reductively eliminate Pb(0) at or below room temperature. This is also in start contrast to the stability of the lighter Si, Ge and Sn congeners.</div>

Structural Evolution Upon Annealing of Multi-Layer Si/Fe Thin Films Prepared by Magnetron Sputtering

2007 ◽  
Vol 561-565 ◽  
pp. 1161-1164
Author(s):  
Xiao Na Li ◽  
Bing Hu ◽  
Chuang Dong ◽  
Xin Jiang
Keyword(s):  
Thin Films ◽  
Magnetron Sputtering ◽  
Room Temperature ◽  
Structural Evolution ◽  
Radio Frequency Magnetron Sputtering ◽  
Transmission Electron ◽  
Direct Band ◽  
The Stability ◽  
Sputtering System

Fe/Si multi-layer films were fabricated on Si (100) substrates utilizing radio frequency magnetron sputtering system. Si/β-FeSi2 structure was found in the films after the deposition. Structural characterization of Fe-silicide sample was performed by transmission electron microscopy, to explore the dependence of the microstructure of β-FeSi2 film on the preparation parameters. It was found that β-FeSi2 particles were formed after the deposition without annealing, whose size is less than 20nm ,with a direct band-gap of 0.94eV in room temperature. After annealing at 850°C, particles grow lager, however the stability of thin films was still good.

Thermal Characterization of Cu/CoFe Multilayer for Giant Magnetoresistive (GMR) Head Applications

2004 ◽  
Author(s):  
Y. Yang ◽  
M. Asheghi
Keyword(s):  
Giant Magnetoresistance ◽  
Room Temperature ◽  
Boltzmann Transport Equation ◽  
Thermal Characterization ◽  
Disk Drive ◽  
Boltzmann Transport ◽  
Self Heating ◽  
Superlattice Structure ◽  
Metallic Ferromagnet

Giant Magnetoresistance (GMR) head technology is one of the latest advancement in hard disk drive (HDD) storage industry. The GMR head superlattice structure consists of alternating layers of extremely thin metallic ferromagnet and paramagnet films. A large decrease in the resistivity from antiparallel to parallel alignment of the film magnetizations can be observed, known as giant magnetoresistance (GMR) effect. The present work characterizes the in-plane electrical and thermal conductivities of Cu/CoFe GMR multilayer structure in the temperature range of 50 K to 340 K using Joule-heating and electrical resistance thermometry in suspended bridges. The thermal conductivity of the GMR layer monotonously increased from 25 Wm−1K−1 (at 55 K) to nearly 50 Wm−1K−1 (at room temperature). We also report the GMR ratio of 17% and a large negative magnetothermal resistance effect (GMTR) of 33% in Cu/CoFe superlattice structure. The Boltzmann transport equation (BTE) is used to estimate the GMR ratio, and to investigate the effect of repeats, as well as the spin-dependent interface and boundary scatting on the transport properties of the GMR structure. Aside from the interesting underlying physics, these data can be used in the predictions of the Electrostatic Discharge (ESD) failure and self-heating in GMR heads.

scholarly journals Thermal characterization of novel aliphatic polyesters with ether and thioether linkages

e-Polymers ◽  
2010 ◽  
Vol 10 (1) ◽  
Author(s):  
M. Soccio ◽  
N. Lotti ◽  
L. Finelli ◽  
A. Munari
Keyword(s):  
Thermal Stability ◽  
Molecular Weight ◽  
Chemical Structure ◽  
Room Temperature ◽  
Crystallization Rate ◽  
Thermal Characterization ◽  
Scanning Calorimetry ◽  
Aliphatic Polyesters ◽  
Good Thermal Stability

AbstractSeveral novel ether or thioether linkage containing aliphatic polyesters and poly(alkylene dicarboxylate)s were synthesized for comparison and characterized in terms of chemical structure and molecular weight. The thermal behavior was examined by thermogravimetric analysis and differential scanning calorimetry. All the polymers showed a good thermal stability, even though lower for the ether or thioether linkage-containing polyesters. The decrement of the thermal stability appears to be more relevant in the case of the presence of sulphur atoms. At room temperature the samples appeared semicrystalline, except PTTDG and PDEDG, which were viscous oils; the effect of the introduction of ether or thioether group was an increment of the Tgvalue, a decrement of the melting temperature and a significant decrease of the crystallization rate. The entity of the variations was found to be affected by the kind of group introduced, and the trend observed can be explained on the basis of atom electronegativity and dimensions

scholarly journals Development and characterization of marine fibre enriched biscuits

2020 ◽  
Vol 11 (2) ◽  
pp. 140-150
Author(s):  
Ninisha Babu ◽  
P. J. Gopika ◽  
Ammu Dinakaran ◽  
Maya Raman ◽  
T.V. Sankar ◽  
...  
Keyword(s):  
Room Temperature ◽  
Morphological Changes ◽  
Age Groups ◽  
Food Product ◽  
Red Seaweeds ◽  
Natural Polysaccharide ◽  
Textural Characterization ◽  
Colour Changes ◽  
The Stability

A biscuit is a flour-based baked food product which is accepted by all age groups. Carrageenan is a natural polysaccharide obtained from red seaweeds andis a rich source of fibre. The diets rich in fibre have a positive effect on health, thus, carrageenan was incorporated into biscuits to enhance the fibre content. Different percentages (2 to 6%) of carrageenan were incorporated in biscuits among which 6 per cent was found to be the best. Fibre rich biscuits were subjected to physiochemical analysis. The antioxidant activity and total polyphenol contents were estimated. Snap test to determine the crispiness and textural characterization of biscuit was performed and Scanning Electron Microscopy (SEM) was done to compare the morphological changes in the products due to addition of carrageenan. The stability of the product at room temperature was analysed by monitoring the textural and colour changes and development of rancidity in the product. The storage studies have revealed a shelf-life of 63 days for the product at room temperature when packed in polypropylene trays.

scholarly journals Structure-based Design of Prefusion-stabilized SARS-CoV-2 Spikes

2020 ◽  
Author(s):  
Ching-Lin Hsieh ◽  
Jory A. Goldsmith ◽  
Jeffrey M. Schaub ◽  
Andrea M. DiVenere ◽  
Hung-Che Kuo ◽  
...  
Keyword(s):  
Room Temperature ◽  
Protein A ◽  
Public Health Emergency ◽  
High Yield ◽  
The Novel ◽  
Yield Production ◽  
Novel Coronavirus ◽  
Serological Diagnostics ◽  
High Yield Production

ABSTRACTThe COVID-19 pandemic caused by the novel coronavirus SARS-CoV-2 has led to accelerated efforts to develop therapeutics, diagnostics, and vaccines to mitigate this public health emergency. A key target of these efforts is the spike (S) protein, a large trimeric class I fusion protein that is metastable and difficult to produce recombinantly in large quantities. Here, we designed and expressed over 100 structure-guided spike variants based upon a previously determined cryo-EM structure of the prefusion SARS-CoV-2 spike. Biochemical, biophysical and structural characterization of these variants identified numerous individual substitutions that increased protein yields and stability. The best variant, HexaPro, has six beneficial proline substitutions leading to ∼10-fold higher expression than its parental construct and is able to withstand heat stress, storage at room temperature, and multiple freeze-thaws. A 3.2 Å-resolution cryo-EM structure of HexaPro confirmed that it retains the prefusion spike conformation. High-yield production of a stabilized prefusion spike protein will accelerate the development of vaccines and serological diagnostics for SARS-CoV-2.

Analysis of the Ash from One Shanghai Plant Using XRD (X-Ray Diffraction)

2013 ◽  
Vol 664 ◽  
pp. 232-235
Author(s):  
Guo Xian Ma ◽  
Hai Ying Zhang
Keyword(s):  
Fly Ash ◽  
Pollution Control ◽  
Room Temperature ◽  
Thermal Characterization ◽  
Xrd Analysis ◽  
Air Pollution Control ◽  
X Ray Diffraction ◽  
X Ray ◽  
Calcium Silicates

This study aims to develop a methodology for thermal characterization of APC (air pollution control)fly ash using XRD (X-ray diffraction). It performed XRD analysis as a function of temperature between room temperature and 1200 °C. It is found that major mineralogical components of fly ash involve SiO2, CaCl2, Ca3Si2O7, Ca2SiO4–0.35H2O, Ca9Si6O21–H2O, K2Al2Si2O8–3.8H2O and AlCl3–4Al(OH)3–4H2O. Glass phases account for around 57%, which is conducive to reduction of energy in recycling of the ash. Salts decompose firstly with increase of temperature and then oxides derived from the decomposition process react with SiO2, forming silicates, calcium-silicates and aluminosilicates.

Thermal Characterization of Cu∕CoFe Multilayer for Giant Magnetoresistive Head Applications

2005 ◽  
Vol 128 (2) ◽  
pp. 113-120 ◽  
Author(s):  
Y. Yang ◽  
R. M. White ◽  
M. Asheghi
Keyword(s):  
Electrical Resistance ◽  
Multilayer Structure ◽  
Giant Magnetoresistance ◽  
Room Temperature ◽  
Thermal Characterization ◽  
Disk Drive ◽  
Multilayer Structures ◽  
Large Decrease ◽  
Resistance Thermometry

Giant magnetoresistance (GMR) head technology is one of the latest advancements in the hard disk drive (HDD) storage industry. The GMR head multilayer structure consists of alternating layers of extremely thin metallic ferromagnetic and nonmagnetic films. A large decrease in the electrical resistivity from antiparallel to parallel alignment of the film magnetizations is observed, known as the GMR effect. The present work characterizes the in-plane electrical and thermal conductivities of Cu∕CoFe GMR multilayer structures in the temperature range of 50K to 340K using Joule-heating and electrical resistance thermometry on suspended bridges. The thermal conductivity of the GMR layer monotonically increases from 25Wm−1K−1 (at 55K) to nearly 50Wm−1K−1 (at room temperature). We also report a GMR ratio of 17% and a large magnetothermal resistance effect (GMTR) of 25% in the Cu∕CoFe multilayer structure.

Thermal characterization of novel aliphatic polyesters with ether and thioether linkages

e-Polymers ◽  
2011 ◽  
Vol 11 (1) ◽  
Author(s):  
M. Soccio ◽  
N. Lotti ◽  
L. Finelli ◽  
A. Munari
Keyword(s):  
Thermal Stability ◽  
Molecular Weight ◽  
Chemical Structure ◽  
Room Temperature ◽  
Crystallization Rate ◽  
Thermal Characterization ◽  
Scanning Calorimetry ◽  
Aliphatic Polyesters ◽  
Good Thermal Stability

AbstractSeveral novel ether or thioether linkage containing aliphatic polyesters and poly(alkylene dicarboxylate)s for comparison were synthesized and characterized in terms of chemical structure and molecular weight. The thermal behavior was examined by thermogravimetric analysis and differential scanning calorimetry. All the polymers showed a good thermal stability, even though lower for the ether or thioether linkage-containing polyesters. The decrement of the thermal stability appears to be more relevant in the case of presence of sulphur atoms. At room temperature the samples appeared semicrystalline, except PTTDG and PDEDG, which were viscous oils; the effect of the introduction of ether or thioether group was an increment of the Tg value, a decrement of the melting temperature and a significant decrease of the crystallization rate. The entity of the variations was found to be affected by the kind of group introduced, and the trend observed can be explained on the basis of atom electronegativity and dimensions.

scholarly journals Design, Preparation and Thermal Characterization of Polystyrene Composites Reinforced with Novel Three-Cages POSS Molecules

Molecules ◽  
2020 ◽  
Vol 25 (13) ◽  
pp. 2967
Author(s):  
Ignazio Blanco ◽  
Francesco Agatino Bottino ◽  
Gianluca Cicala ◽  
Giulia Ognibene ◽  
Claudio Tosto
Keyword(s):  
1H Nmr Spectroscopy ◽  
In Situ Polymerization ◽  
Thermal Characterization ◽  
Scanning Calorimetry ◽  
Single Cage ◽  
The Stability ◽  
First Time ◽  
Thermal Stability Of

Novel polystyrene (PS)/polyhedral oligomeric silsequioxanes (POSSs) nanocomposites were designed and prepared by in situ polymerization, using, for the first time, three-cage POSS molecules. The synthesized compounds were first characterized by Fourier transform infrared spectroscopy (FTIR) and 1H NMR spectroscopy to verify the obtaining of the designed products before their thermal performance was evaluated and compared with those of pristine PS and the corresponding single-cage POSSs nanocomposites. The thermal behaviour was checked by the means of the differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). Scanning electron microscopy (SEM) was also used to confirm the hypothesis about the dispersion/aggregation of the POSS molecules into the polymer matrix. The parameters chosen to evaluate the thermal stability of the investigated compounds, namely temperature at 5% of mass loss (T5%) and solid residue at 700 °C, showed a significant increase in the stability of the polymers reinforced with the three-cages POSS, in comparison to both PS and single-cage POSS reinforced PSs, which therefore turn out to be promising molecular fillers for nanocomposite production.

Sign in / Sign up

Export Citation Format

Share Document