Point Defects, Dislocations in GaAs and Material Homogeneity

1987 ◽  
Vol 104 ◽  
Author(s):  
J. C. Bourgoin ◽  
H. J. von Bardeleben ◽  
H. Lin ◽  
D. Stievenard
Keyword(s):  
Thermal Analysis ◽  
Differential Thermal Analysis ◽  
Positron Annihilation ◽  
Point Defects ◽  
Bulk Gaas ◽  
Material Homogeneity

ABSTRACTCombined positron annihilation and differential thermal analysis have shown that, in bulk GaAs materials, dislocations are decorated with vacancy related defects which recombine with As interstitials originating from As clusters. The role of these dislocations, the role of As source of these clusters are described and the consequences on the material homogeneity discussed.

Dielectric-differential thermal analysis IV the role of water

1987 ◽  
Vol 32 (4) ◽  
pp. 1271-1276 ◽  
Author(s):  
M. Carreras ◽  
R. Roque-Malherbe ◽  
C. de las Pozas
Keyword(s):  
Thermal Analysis ◽  
Differential Thermal Analysis

scholarly journals Люминесцентные свойства разнолигандных beta-дикетонатов неодима, полученных в среде сверхкритического диоксида углерода в полимерных матрицах различной природы

2020 ◽  
Vol 129 (7) ◽  
pp. 869
Author(s):  
В.С. Каплин ◽  
А.С. Копылов ◽  
Т.С. Зархина ◽  
П.С. Тимашев ◽  
А.Б. Соловьева
Keyword(s):  
Carbon Dioxide ◽  
Thermal Analysis ◽  
Differential Thermal Analysis ◽  
Polymer Matrix ◽  
Supercritical Co2 ◽  
Binary Systems ◽  
Ternary Systems ◽  
Mixed Ligand ◽  
Luminescence Spectra

Multi-ligand phosphor complexes of neodymium acetylacetonate with phenanthroline are synthesized in polymer matrices (oligourethane methacrylate, fluoroplast, polycarbonate) in supercritical carbon dioxide medium. At the same time the role of one of the ligands in such complexes is played by fragments of the polymer matrix. The luminescence spectra of the obtained ternary systems are described. It was shown that the position of the luminescence maxima is bathochromically shifted relative to the binary systems Nd(Acac)3/polymer obtained in a similar way and the magnitude of the shift depends on the nature of the polymer matrix. It was shown that upon the introduction of these components into polymers from a solution, similar phosphor mixed-ligand neodymium complexes do not form. The formation of new structures Nd(Acac)3/Phen/polymer upon impregnation of oligourethane methacrylate with neodymium β-diketonate and phenanthroline in a supercritical CO2 medium was confirmed by the method of differential thermal analysis. The same method confirmed that with the introduction of these components from the solution of the above systems do not form.

Volatility studies of metal chelates. V. Stability and volatility of transition metal chelates of tetradentate Schiff bases

1981 ◽  
Vol 34 (8) ◽  
pp. 1579 ◽  
Author(s):  
S Dilli ◽  
E Patsalides
Keyword(s):  
Thermal Stability ◽  
Thermal Analysis ◽  
Differential Thermal Analysis ◽  
Metal Ion ◽  
Metal Chelates ◽  
Acid Base ◽  
Substituent Group ◽  
Transition Metal Chelates ◽  
Distinctive Role

A study of the effect of substituent groups on the thermal stability and volatility of 15 tetradentate β-keto enamines and various copper(II), nickel(II), palladium(II), cobalt(II), and oxovanadium(IV) derivatives has been made by employing simultaneous thermogravimetry and differential thermal analysis. The majority of these chelates are stable at temperatures above 300°C although volatilities are significantly lower than for the corresponding β-diketonates. Trends in the volatilities of the copper(II), nickel(II), palladium(II) and oxovanadium(IV) chelates are rationalized in terms of substituent-group effects on the polarity and intermolecular Lewis acid-base interactions. The distinctive role of the metal ion in controlling chelate volatility is also discussed.

scholarly journals Structural and physical properties of Fe2O3-doped lead vanadate glass

2000 ◽  
Vol 15 (1) ◽  
pp. 218-221 ◽  
Author(s):  
S. Mandal ◽  
S. Hazra
Keyword(s):  
Thermal Analysis ◽  
Differential Thermal Analysis ◽  
Physical Properties ◽  
Glass Network ◽  
Building Blocks ◽  
X Ray Diffraction ◽  
Vanadium Iron ◽  
Lead Vanadate ◽  
Vanadate Glasses

The role of Fe2O3in the structural and physical properties of ternary lead vanadium iron glass system has been studied in comparison with the binary lead vanadate glasses. X-ray diffraction, scanning electron microscopy, and differential thermal analysis show that homogeneous glasses of composition 10Fe2O3 · xV2O5 · (90 − x)PbO can be obtained for x = 50 to 80 mol%. Observation from the infrared spectroscopy shows that the basic building blocks of these glasses are same as those of crystalline V2O5, while differential thermal analysis and electrical conduction of these glasses suggest that there is a strong role of iron, both in the glass network and in the conduction mechanism for the glasses containing a low percentage of vanadium.

STRUCTURAL INVESTIGATIONS ON CALCIUM-SILICA-PHOSPHATE GLASSES

2002 ◽  
Vol 16 (20) ◽  
pp. 761-767 ◽  
Author(s):  
V. SIMON ◽  
S. SIMON ◽  
D. ENIU
Keyword(s):  
Thermal Analysis ◽  
Differential Thermal Analysis ◽  
Glass Matrix ◽  
Structural Changes ◽  
Structural Evolution ◽  
Phosphate Glasses ◽  
Structural Investigations ◽  
Intermediate Range Order ◽  
Ionic Field

Glass transition and crystallization temperatures established from differential thermal analysis (DTA), density, molar volume and ionic field strength changes induced by the addition of Fe 2 O 3 to the CaO-P 2 O 5- SiO 2 glass matrix, are correlated in order to understand the structural role of iron oxide in the investigated glasses and to discover the structural evolution of the samples as a function of composition. The compactness degree in calcium-silica-phosphate glasses increases when Fe 2 O 3 is added. The results suggest structural changes characteristic of intermediate range order.

Zeolites Fit For A Crown: Probing Host-Guest Interactions with Thermogravimetric Methods

2018 ◽  
Author(s):  
Asel Sartbaeva ◽  
Paul R. Raithby ◽  
Remi Castaing ◽  
Antony Nearchou
Keyword(s):  
Mass Spectrometry ◽  
Thermal Analysis ◽  
Differential Thermal Analysis ◽  
Petrochemical Industry ◽  
Rational Use ◽  
New Methodologies ◽  
First Time ◽  
Kinetics Of

Through a combination of thermogravimetry, mass spectrometry and differential thermal analysis, we demonstrate for the first time that all four zeolites show experimental differences in their host-guest interactions with 18C6. In addition, we have estimated the kinetics of 18C6 decomposition, which is a technique that has not been applied to zeolites previously. Using these findings as a toolkit, a more rational use of OSDAs can be utilised to prepare designer zeolites. Furthermore, the new methodologies presented herein can be applied to current zeolites, such as MFI-type zeolites used in the petrochemical industry.

PHASE EQUILIBRIUM IN THE AS2TE3-TM2TE3 SYSTEM.

2020 ◽  
Vol 5 (8(77)) ◽  
pp. 65-68
Author(s):  
Teymur Mammad Ilyasly ◽  
Rahman Hasanaga Fatullazade ◽  
Zakir Islam Ismailov ◽  
Nigar Nadir Jafarova
Keyword(s):  
Thermal Analysis ◽  
Solid Solution ◽  
Differential Thermal Analysis ◽  
Phase Equilibrium ◽  
Physicochemical Properties ◽  
Thermal Effects ◽  
Isothermal Annealing ◽  
Intermediate Phase ◽  
Physicochemical Analysis ◽  
Two Phases

The synthesis of alloys of the system was carried out stepwise in rotary furnaces. The synthesis mode was selected based on the physicochemical properties of the elementary components. For homogenization, the alloys were subjected to isothermal annealing at 750 and 1275 K, depending on the Tm2Te3 concentration, for 250 h after homogenization of the alloys, they were subjected to physicochemical analysis. The results of differential thermal analysis showed that reversible thermal effects are observed in the alloys of the system. In alloys in a 1: 1 ratio, a new intermediate phase is formed with a composition corresponding to the TmAsTe3 compound. The homogeneity area is observed in the concentration range 52.5-47.5. It was found that in the concentration range 98.5-52.5 Tm2Te3 there are two phases - a mixture of β and of the solid solution, and in the concentration range of 47.51 mol% Tm2Te3 phases and α are in equilibrium. ) 66 The eutectic has coordinates of 11.5 mol Tm2Te3 at a temperature of 575 K.

PENINGKATAN LAJU DISOLUSI ACYCLOVIR DENGAN METODE SISTEM DISPERSI PADAT MENGGUNAKAN POLOXAMER 188

2016 ◽  
Vol 5 (1) ◽  
pp. 6
Author(s):  
Budi Setiawan ◽  
Erizal Zaini ◽  
Salman Umar
Keyword(s):  
Electron Microscopy ◽  
Thermal Analysis ◽  
Scanning Electron Microscopy ◽  
Fourier Transform ◽  
Differential Thermal Analysis ◽  
Fourier Transform Infrared ◽  
X Ray Diffraction ◽  
Poloxamer 188 ◽  
X Ray ◽  
Scanning Electron

Sebuah penelitian tentang sistem dispersi padat dari asiklovir dengan poloxamer 188 telah dilakukan formulasi dengan pencampuran secara fisika dengan rasio 1 : 1, 1 : 3, 1 : 5 dan dispersi padat 1 : 1, 1 : 3, 1 : 5 dan penggilingan 1:1 sebagai pembanding. Dispersi padat dibuat menggunakan metode pencairan (fusi), yang digabung dengan poloxamer 188 pada hotplate kemudian asiklovir dimasukkan ke dalam hasil poloxamer 188 lalu di kocok hingga membentuk masa homogen. Semua formula yang terbentuk termasuk asiklovir poloxamer 188 murni dianalisis karakterisasinya dengan Differential Thermal Analysis (DTA), X-ray Diffraction, Scanning Electron Microscopy (SEM), dan Fourier Transform Infrared (FTIR), kemudian pengambilan dilakukan  (penentuan kadar) mengunakan spektrofotometer UV pada panjang gelombang 257,08 nm dan uji laju disolusi dengan aquadest bebas CO2 menggunakan metode dayung. Hasil pengambilan  (penentuan kadar) menunjukkan bahwa semua formula memenuhi persyaratan farmakope Amerika edisi 30 dan farmakope Indonesia edisi 4 yaitu 95-110%. Sedangkan hasil uji laju disolusi untuk campuran fisik 1: 1, dan dispersi padat 1: 1, dan penggilingan 1: 1 menunjukkan peningkatan yang nyata dibandingkan asiklovir murni. Hal ini juga dapat dilihat dari hasil perhitungan statistik  menggunakan analisis varian satu arah  SPSS 17.

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