Molecular Motions and Phase Transitions in [(CH3)4N]2MBr6 (M: Pt, Te, Sn). A Proton Magnetic Relaxation, Differential Thermal Analysis, and Powder X-Ray Diffraction Study

1982 ◽  
Vol 86 (10) ◽  
pp. 936-941 ◽  
Author(s):  
Setsuko Sato ◽  
Ryuichi Ikeda ◽  
Daiyu Nakamura
Keyword(s):  
Thermal Analysis ◽  
Differential Thermal Analysis ◽  
Phase Transitions ◽  
Diffraction Study ◽  
Magnetic Relaxation ◽  
Molecular Motions ◽  
X Ray Diffraction ◽  
X Ray ◽  
Proton Magnetic Relaxation

Structures and phase transitions of (BrCH2CH2NH3)2CdBr4 and (BrCH2CH2CH2NH3)2CdBr4 as investigated by 81Br NQR, DTA, and single-crystal X-ray diffraction

2020 ◽  
Vol 75 (3) ◽  
pp. 295-302
Author(s):  
Hideta Ishihara ◽  
Asuka Koga ◽  
Koh-ichi Suzuki ◽  
Hiromitsu Terao
Keyword(s):  
Thermal Analysis ◽  
Hydrogen Bonding ◽  
Differential Thermal Analysis ◽  
Phase Transitions ◽  
Hydrogen Bonds ◽  
Layered Perovskite ◽  
X Ray Diffraction ◽  
X Ray ◽  
81Br Nqr ◽  
Successive Phase

AbstractThe crystal structures of (BrCH2CH2NH3)2CdBr4 (1) and (BrCH2CH2CH2NH3)2CdBr4 (2) have been determined at T = 113 K: orthorhombic, Pbcn, a = 843.8(4), b = 775.4(4), c = 2339.6(11) pm, Z = 4 for 1; orthorhombic, Pbcn, a = 858.7(3), b = 783.6(2), c = 2519.4(7) pm, Z = 4 for 2. Both crystals are isomorphic, showing distinctive layered perovskite-related structures, in which the cations orient their aliphatic parts toward each other in their cation layers and connect to the infinite anion layers with their ammonium parts through N–H · · · Br hydrogen bonds. 81Br NQR and differential thermal analysis measurements for both compounds revealed the existence of successive phase transitions as seen in n-(CH3CH2CH2NH3)2CdBr4 (3). These phase transitions appear to be induced by the activated motions of the cations. The changes in the hydrogen bonding schemes resulting from the motions of the cations lead to the different phases of the respective crystals.

Differential Thermal Analysis Studies on Ag2CO3

1971 ◽  
Vol 49 (24) ◽  
pp. 3986-3993 ◽  
Author(s):  
G. D. Nagy ◽  
J. B. Vergette ◽  
J. P. Connolly
Keyword(s):  
Thermal Analysis ◽  
Differential Thermal Analysis ◽  
Phase Transitions ◽  
Diffraction Pattern ◽  
X Ray Diffraction ◽  
Heating Rates ◽  
X Ray ◽  
Heating And Cooling ◽  
Reversible Phase ◽  
Silver Metal

The decomposition and phase transitions that occur during the heating and cooling of Ag2CO3 were studied by differential thermal analysis at heating rates of 7 to 14° per min. In helium, the Ag2CO3 was partially decomposed evolving CO2 (7–35% depending upon the method of preparation) giving rise to peaks at 190 to 200°; at 350 to 400°, two endothermic peaks were observed at which CO2 and O2 were given off simultaneously, leaving silver metal. In CO2 the initial partial decomposition gave rise to a peak at about 265°. The partially decomposed Ag2CO3 (Ag2O•nCO2, where n is less than one) gave the same X-ray diffraction pattern as Ag2O, which slowly converted to that for Ag2CO3 if left exposed to air or CO2. The Ag2O•nCO2 undergoes two distinct "reversible" phase transitions at 180 and 197° on subsequent reheatings. The Ag2O•nCO2 behaves like a clathrate-type of structure in which CO2 can be entrapped in the Ag2O lattice.

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.

scholarly journals The Potential for Natural Stones from Northeastern Brazil to Be Used in Civil Construction

Minerals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 440
Author(s):  
Fabiana Pereira da Costa ◽  
Jucielle Veras Fernandes ◽  
Luiz Ronaldo Lisboa de Melo ◽  
Alisson Mendes Rodrigues ◽  
Romualdo Rodrigues Menezes ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Thermal Analysis ◽  
Differential Thermal Analysis ◽  
Chemical Resistance ◽  
Mechanical Analysis ◽  
Northeastern Brazil ◽  
X Ray Diffraction ◽  
X Ray ◽  
Chemical Agents ◽  
Natural Stones

Natural stones (limestones, granites, and marble) from mines located in northeastern Brazil were investigated to discover their potential for use in civil construction. The natural stones were characterized by chemical analysis, X-ray diffraction, differential thermal analysis, and optical microscopy. The physical-mechanical properties (apparent density, porosity, water absorption, compressive and flexural strength, impact, and abrasion) and chemical resistance properties were also evaluated. The results of the physical-mechanical analysis indicated that the natural stones investigated have the potential to be used in different environments (interior, exterior), taking into account factors such as people’s circulation and exposure to chemical agents.

X-ray diffraction study of phase transitions in iron(II) trisnioximate hexadecylboronate clathrochelate complex

2001 ◽  
Vol 46 (5) ◽  
pp. 758-770 ◽  
Author(s):  
I. I. Vorontsov ◽  
K. A. Potekhin ◽  
M. Yu. Antipin ◽  
Ya. Z. Voloshin ◽  
A. I. Stash ◽  
...  
Keyword(s):  
Phase Transitions ◽  
Diffraction Study ◽  
X Ray Diffraction ◽  
X Ray

The Roman Ceramics of Salobrena (Granada-Spain) and their Raw Materials

1992 ◽  
Vol 267 ◽  
Author(s):  
Ana M De Andres ◽  
Isabel MuÑOZ
Keyword(s):  
Thermal Analysis ◽  
Differential Thermal Analysis ◽  
Raw Materials ◽  
Third Century ◽  
Western Coast ◽  
X Ray Diffraction ◽  
X Ray ◽  
The Third ◽  
Good Number ◽  
Scanning Electron

ABSTRACTNineteen roman ceramic sherds found near Salobreña (Granada, Spain), in the western coast of the Mediterranean Sea, as well as different ceramic clays from the surroundingsare studied. Both clays and ceramic sherds are characterizad by X-ray diffraction and spectrometry, differential thermal analysis, and scanning electron and optical microscopies. A good number of the ceramic pieces, among which some “Terrae Sigillatae”, have a composition similar to that of the local clays and, thus, have been probably manufactured at Salobreña. Only a few of them have a foreign origin. For most of them, the firing temperature was about 800-850 °C, although some have been produced at 900-1000 °C, and some others at 1000-1100 °C. It is concluded that Salobreña appearsto have been an important settlement just in the third century of the Christian era.

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