scholarly journals THE EFFECT OF THE EXTERNAL MEDIUM ON THE STRUCTURAL-PHASE TRANSFORMATIONS OF QUARTZITE UPON HIGH-ENERGY ELECTRON IRRADIATION

2019 ◽  
pp. 30-34
Author(s):  
E.P. Bereznyak ◽  
I.V. Kolodiy ◽  
Yu.S. Khodyreva
Keyword(s):  
Crystal Structure ◽  
Electron Irradiation ◽  
Structural Phase ◽  
High Energy ◽  
Water Medium ◽  
X Ray Diffraction ◽  
Water Stream ◽  
Radiation Annealing ◽  
Initial Crystal ◽  
Structural Phase Transformations

The structural transformations of the natural quartzite under the electron irradiation in doses range of 107…108 Gy in various medium were studied using IR-spectroscopy, X-ray diffraction, and crystal-optical analyzes. It was established that under the irradiation, both in air and in a water stream, intense crystallization of the amorphous component occurs, which is siliceous cement. The initial crystal structure of quartzite is also improved as a result of radiation annealing of defects and impurities present in the initial quartz. It was found that the water medium significantly accelerates these processes, however, in the studied doses range for both types of irradiation, degradation of the quartzite crystal structure is not observed.

Relaxor Properties and Tunability of Electron-Irradiated Thin Poly(vinlidene fluoride-trifluoroethylene) Copolymer Film

2012 ◽  
Vol 560-561 ◽  
pp. 892-898 ◽  
Author(s):  
Li Tian ◽  
Xiang Jian Meng ◽  
Jing Yang ◽  
Jing Lan Sun ◽  
Sheng Zhao Yuan ◽  
...  
Keyword(s):  
Electron Irradiation ◽  
Dielectric Spectroscopy ◽  
High Energy ◽  
Copolymer Film ◽  
Relaxor Behavior ◽  
High Energy Electron ◽  
X Ray Diffraction ◽  
Gauche Conformation ◽  
Trans Conformation ◽  
X Ray

The effect of high energy electron irradiation on poly(vinlidene fluoride-trifluoroethylene) copolymer film with thickness about 180 nm has been studied. Both dielectric spectroscopy investigation and X-Ray Diffraction show that all-trans conformation of pre-irradiated films is transformed to trans-gauche conformation after irradiation. The relaxor behavior of irradiated sample obeys the modified Curie-Weiss and Vogel-Fulcher law. And the tunability is increased from 42% to 63% after irradiation.

scholarly journals Structural Phase Transition and Related Thermoelectric Properties in Sn Doped AgBiSe2

Crystals ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1016
Author(s):  
Xiao-Cun Liu ◽  
Ming-Yan Pan
Keyword(s):  
Crystal Structure ◽  
Phase Transition ◽  
Thermal Conductivity ◽  
Thermoelectric Properties ◽  
Thermoelectric Material ◽  
Structural Phase Transition ◽  
Structural Phase ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Complex Structural

AgBiSe2, which exhibits complex structural phase transition behavior, has recently been considered as a potential thermoelectric material due to its intrinsically low thermal conductivity. In this work, we investigate the crystal structure of Sn-doped AgBiSe2 through powder X-ray diffraction and differential scanning calorimetry measurements. A stable cubic Ag1−x/2Bi1−x/2SnxSe2 phase can be obtained at room temperature when the value of x is larger than 0.2. In addition, the thermoelectric properties of Ag1−x/2Bi1−x/2SnxSe2 (x = 0.2, 0.25, 0.3, 0.35) are investigated, revealing that Ag1−x/2Bi1−x/2SnxSe2 compounds are intrinsic semiconductors with a low lattice thermal conductivity. This work provides new insights into the crystal structure adjustment of AgBiSe2 and shows that Ag1−x/2Bi1−x/2SnxSe2 is a potentially lead-free thermoelectric material candidate.

scholarly journals Crystal Structure Evolution, Microstructure Formation, and Properties of Mechanically Alloyed Ultrafine-Grained Ti-Zr-Nb Alloys at 36≤Ti≤70 (at. %)

Materials ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 587 ◽  
Author(s):  
Marczewski ◽  
Miklaszewski ◽  
Maeder ◽  
Jurczyk
Keyword(s):  
Crystal Structure ◽  
Mechanical Alloying ◽  
Pure Titanium ◽  
Young Modulus ◽  
High Energy ◽  
Structure Evolution ◽  
X Ray Diffraction ◽  
Mechanically Alloyed ◽  
Ultrafine Grained ◽  
Energy Ball

Titanium β-type alloys are preferred biomaterials for hard tissue replacements due to the low Young modulus and limitation of harmful aluminum and vanadium present in the commercially available Ti6Al4V alloy. The aim of this study was to develop a new ternary Ti-Zr-Nb system at 36≤Ti≤70 (at. %). The technical viability of preparing Ti-Zr-Nb alloys by high-energy ball-milling in a SPEX 8000 mill has been studied. These materials were prepared by the combination of mechanical alloying and powder metallurgy approach with cold powder compaction and sintering. Changes in the crystal structure as a function of the milling time were investigated using X-ray diffraction. Our study has shown that mechanical alloying supported by cold pressing and sintering at the temperature below α→β transus (600°C) can be applied to synthesize single-phase, ultrafine-grained, bulk Ti(β)-type Ti30Zr17Nb, Ti23Zr25Nb, Ti30Zr26Nb, Ti22Zr34Nb, and Ti30Zr34Nb alloys. Alloys with lower content of Zr and Nb need higher sintering temperatures to have them fully recrystallized. The properties of developed materials are also engrossing in terms of their biomedical use with Young modulus significantly lower than that of pure titanium.

Structural stability of WS2 under high pressure

2014 ◽  
Vol 28 (25) ◽  
pp. 1450168 ◽  
Author(s):  
Nirup Bandaru ◽  
Ravhi S. Kumar ◽  
Jason Baker ◽  
Oliver Tschauner ◽  
Thomas Hartmann ◽  
...  
Keyword(s):  
Crystal Structure ◽  
High Pressure ◽  
High Temperature ◽  
Structural Changes ◽  
High Pressures ◽  
Structural Phase ◽  
X Ray Diffraction ◽  
X Ray ◽  
Diamond Anvil ◽  
Heating Up

Structural behavior of bulk WS 2 under high pressure was investigated using synchrotron X-ray diffraction and diamond anvil cell up to 52 GPa along with high temperature X-ray diffraction and high pressure Raman spectroscopy analysis. The high pressure results obtained from X-ray diffraction and Raman analysis did not show any pressure induced structural phase transformations up to 52 GPa. The high temperature results show that the WS 2 crystal structure is stable upon heating up to 600°C. Furthermore, the powder X-ray diffraction obtained on shock subjected WS 2 to high pressures up to 10 GPa also did not reveal any structural changes. Our results suggest that even though WS 2 is less compressible than the isostructural MoS 2, its crystal structure is stable under static and dynamic compressions up to the experimental limit.

Synthesis, crystal structure, and X-ray diffraction data of lithium m-phenylenediamine sulfate Li2(C6H10N2)(SO4)2

2021 ◽  
pp. 1-5
Author(s):  
Junyan Zhou ◽  
Congcong Chai ◽  
Munan Hao ◽  
Xin Zhong
Keyword(s):  
Crystal Structure ◽  
Diffraction Data ◽  
Structural Phase ◽  
Measured Temperature ◽  
X Ray Diffraction ◽  
Monoclinic System ◽  
X Ray ◽  
Cell Parameters ◽  
Anisotropic Expansion ◽  
Diffraction Patterns

A new organic–inorganic hybrid lithium m-phenylenediamine sulfate (LPS), Li2(C6H10N2)(SO4)2, was synthesized under aqueous solution conditions. The X-ray powder diffraction study determined that the title compound crystallized in a monoclinic system at 300 K, with unit-cell parameters a = 7.8689(6) Å, b = 6.6353(5) Å, c = 11.8322(10) Å, β = 109.385(3) °, V = 582.77(8) Å3. Indexing of the diffraction patterns collected from 100 to 600 K reveals that LPS has no structural phase transition within the measured temperature range, and the volume expansion coefficient is approximately 2.79 × 10−5 K−1. The crystal structure was solved based on the single-crystal diffraction data with space group P21/m. Lithium and SO42− are found to form quasi-two-dimensional anti-fluorite [LiSO4] layers stacking along the c-axis, with m-phenylenediamine molecules inserted in the anti-fluorite layers and forming hydrogen bonds to the SO42−. This explains a moderate anisotropic expansion in LPS.

scholarly journals Structural Phase Diagram of LaO1−xFxBiSSe: Suppression of the Structural Phase Transition by Partial F Substitutions

2020 ◽  
Vol 5 (4) ◽  
pp. 81
Author(s):  
Kazuhisa Hoshi ◽  
Shunsuke Sakuragi ◽  
Takeshi Yajima ◽  
Yosuke Goto ◽  
Akira Miura ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Phase Diagram ◽  
Low Temperature ◽  
Structural Transition ◽  
Structural Phase ◽  
Tetragonal Structure ◽  
Layered Superconductor ◽  
X Ray Diffraction ◽  
X Ray ◽  
Plane Anisotropy

Recently, the anomalous two-fold-symmetric in-plane anisotropy of superconducting states has been observed in a layered superconductor system, LaO1−xFxBiSSe (x = 0.1 and 0.5), with a tetragonal (four-fold symmetric) in-plane structure. To understand the origin of the phenomena observed in LaO1−xFxBiSSe, clarification of the low-temperature structural phase diagram is needed. In this study, we have investigated the low-temperature crystal structure of LaO1−xFxBiSSe (x = 0, 0.01, 0.02, 0.03, and 0.5). From synchrotron X-ray diffraction experiments, a structural transition from tetragonal to monoclinic was observed for x = 0 and 0.01 at 340 and 240 K, respectively. For x = 0.03, a structural transition and broadening of the diffraction peak were not observed down to 100 K. These facts suggest that the structural transition could be suppressed by 3% F substitution in LaO1−xFxBiSSe. Furthermore, the crystal structure for x = 0.5 at 4 K was examined by low-temperature laboratory X-ray diffraction, which confirmed that the tetragonal structure is maintained at 4 K for x = 0.5. Our structural investigation suggests that the two-fold-symmetric in-plane anisotropy of superconducting states observed in LaO1−xFxBiSSe was not originated from structural symmetry lowering in its average structure. To evaluate the possibility of the local structural modification like nanoscale puddles in the average tetragonal structure, further experiments are desired.

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