scholarly journals Phase Equilibria of the MnTe-Sb2Te3 System and Synthesis of Novel Ternary Layered Compound – MnSb4Te7

2021 ◽  
Vol 22 (1) ◽  
pp. 39-44
Author(s):  
E.N. Orujlu ◽  
Z.S. Aliev ◽  
I.R. Amiraslanov ◽  
M.B. Babanly
Keyword(s):  
Primary Crystallization ◽  
Layered Compound ◽  
Fundamental Parameter ◽  
Bulk Single Crystal ◽  
X Ray Diffraction ◽  
Solution Field ◽  
Title System ◽  
First Time ◽  
Parameter Approach

By using Differential Thermal Analysis (DTA) and Powder X-ray Diffraction (PXRD) techniques, the phase diagram of the MnTe-Sb2Te3 system has been constructed for the first time in the entire composition range. The system features two ternary layered van der Waals (vdW) compounds. Apart from known MnSb2Te4, novel MnSb4Te7 which a structural analogous of the known MnBi4Te7 was found in the system. Crystal structure parameters of both compounds were determined by Rietveld refinement using the fundamental parameter approach. Both compounds were found to decompose via peritectic reactions and possess significant homogeneity ranges. The title system is also characterized by the existence of the wide solid solution field based on the starting Sb2Te3. The present results would be useful for the bulk single crystal growth of both compounds from the liquid phase via the determination of primary crystallization areas.

Unidirectional crystal growth and crystalline perfection ofL-arginine phosphate monohydrate

2012 ◽  
Vol 45 (4) ◽  
pp. 679-685 ◽  
Author(s):  
B. Riscob ◽  
Mohd Shakir ◽  
N. Vijayan ◽  
K. K. Maurya ◽  
M. A. Wahab ◽  
...  
Keyword(s):  
Single Crystal ◽  
Growth Direction ◽  
Wide Frequency Range ◽  
Bulk Single Crystal ◽  
X Ray Diffraction ◽  
Crystalline Perfection ◽  
X Ray ◽  
Hardness Tester ◽  
Device Applications ◽  
First Time

A large (∼20 mm diameter and 80 mm length) single crystal of L-arginine phosphate monohydrate (LAP) has been grown for the first time by the unidirectional Sankaranarayanan–Ramasamy method in an aqueous medium in a specially designed constant-temperature bath. The crystal structure has been confirmed by powder X-ray diffraction. The crystalline perfection was assessed by high-resolution X-ray diffractometry (HRXRD) which found that the quality of the grown single crystal is quite good. HRXRD studies along different directions show that the crystal contains a low density of edge-type dislocations formed along the growth direction. The thermal stability was assessed using thermogravimetric/differential thermal analysis. The mechanical behaviour was studied using an Omnitech micro-hardness tester. The dielectric studies were carried out over a wide frequency range of 10 Hz to 5 MHz at room temperature. The characterization studies reveal that the grown bulk single crystal of LAP is suitable for device applications.

scholarly journals Towards understanding the molecular mechanism of cardiolipin transport in Salmonella typhimurium: interactions between an essential inner membrane protein YejM and its newly found ligand, YejL

F1000Research ◽  
2016 ◽  
Vol 5 ◽  
pp. 1086 ◽  
Author(s):  
Uma Gabale ◽  
Gene Qian ◽  
Elaina Roach ◽  
Susanne Ressl
Keyword(s):  
Membrane Protein ◽  
Drug Targets ◽  
Essential Gene ◽  
The United States ◽  
X Ray Diffraction ◽  
Inner Membrane ◽  
Its Gene ◽  
Inner Membrane Protein ◽  
First Time

Salmonella typhimurium is responsible for over 35% of all foodborne illness related hospitalizations in the United States. This Gram-negative bacterium possesses an inner and an outer membrane (OM), the latter allowing its survival and replication within host tissues. During infection, OM is remodeled by transport of glycerophospholipids across the periplasm and into the OM. Increased levels of cardiolipin in the OM were observed upon PhoPQ activation and led to the discovery of YejM; an inner membrane protein essential for cell growth involved in cardiolipin binding and transport to the OM. Another protein that might be playing a role in cardiolipin transport is YejL, as its gene is localized upstream of yejm on the same operon. Here we report how YejM was engineered to facilitate crystal growth and X-ray diffraction analysis. Furthermore, we present for the first time that YejL is a ligand for YejM. Successful structure determination of YejM and YejL will help us understand how they interact and how YejM facilitates cardiolipin transport to the OM. Ultimately, yejm, being an essential gene, may lead to new drug targets inhibiting the pathogenic properties of S. typhimurium.

scholarly journals Determination of chemical ordering in the complex perovskite Pb(Cd1/3Nb2/3)O3

IUCrJ ◽  
2018 ◽  
Vol 5 (6) ◽  
pp. 808-815 ◽  
Author(s):  
Caiyan Wang ◽  
Zhengqian Fu ◽  
Nan Zhang ◽  
Marek Paściak ◽  
Jian Zhuang ◽  
...  
Keyword(s):  
Antiphase Domain ◽  
The Novel ◽  
X Ray Diffraction ◽  
Complex Perovskite ◽  
Chemical Ordering ◽  
Novel Structure ◽  
Transmission Electron ◽  
Unique Material ◽  
First Time

Pure-phase Pb(Cd1/3Nb2/3)O3 (PCN) single crystals and ceramics with a complex perovskite structure are synthesized for the first time. The local chemical ordering in PCN has been investigated by X-ray diffraction (including diffuse scattering) and Cs-corrected transmission electron microscopy experiments. It is concluded that the PCN samples have large coherent chemical ordering regions that even extend to the long range, and the ordering model is consistent with β-type chemical ordered regions. The antiphase domain boundaries were also observed. Two dielectric anomaly peaks were found in these two types of samples, one of which indicates possible relaxor behaviour. The novel structure of the completely ordered regions and its relationship with the electrical properties make PCN a unique material for the fundamental understanding of chemically substituted perovskites.

Phase Equilibria at 1173K in the Ni-Ti-Al System

1982 ◽  
Vol 19 ◽  
Author(s):  
W.W. Liang ◽  
P. Nash
Keyword(s):  
Experimental Data ◽  
Phase Equilibria ◽  
Microprobe Analysis ◽  
Electron Microprobe Analysis ◽  
Composition Range ◽  
Primary Crystallization ◽  
X Ray Diffraction ◽  
Isothermal Sections ◽  
X Ray

ABSTRACTIn a recent review of the published literature on this system it was concluded that there is a lack of experimental data in this system particularly in regions of the system with less than 75 atomic per cent of each one of the components (1). In order to provide some consistent data over a substantial range of composition an experimental determination of the phase equilibria at 1173K and from 0–50 atomic % Al is being carried out. The main experimental technique being used is quantitative electron microprobe analysis (JEOL 733) by wavelength dispersive x-ray spectrometry. In addition, x-ray diffraction is being used to establish the structures of phases present and optical metallography of cast structures to determine the fields of primary crystallization. In addition to establishing the phase equilibria at this temperature the composition range for the existence of the AlNi2Ti phase is being determined. The results thus far are compared with previous experimental data and calculated isothermal sections (2).

scholarly journals X-ray diffraction by surface acoustic waves

2021 ◽  
Vol 54 (1) ◽  
pp. 180-194
Author(s):  
Dmitry Roshchupkin ◽  
Luc Ortega ◽  
Olga Plotitcyna ◽  
Ivo Zizak ◽  
Simone Vadilonga ◽  
...  
Keyword(s):  
Acoustic Waves ◽  
Surface Acoustic Waves ◽  
Bragg Diffraction ◽  
Total External Reflection ◽  
X Ray Diffraction ◽  
Rocking Curve ◽  
X Ray ◽  
Diffraction Region ◽  
First Time

The possibilities are presented of X-ray diffraction methods for studying the propagation of surface acoustic waves (SAWs) in solids, including diffraction under total external reflection conditions and Bragg diffraction, using acoustically modulated X-ray multilayer mirrors and crystals. SAW propagation was studied using both meridional and sagittal diffraction geometries where the SAW wavevectors and X-ray photons are collinear or perpendicular, respectively. SAW propagation in a crystal leads to sinusoidal modulation of the crystal lattice and the appearance of diffraction satellites on the rocking curve. The intensities and angular positions of these diffraction satellites are determined by the SAW wavelength, amplitude and attenuation. Therefore, diffraction methods allow the analysis of the SAW propagation process and determination of SAW parameters. The influence of X-ray energy on diffraction by acoustically modulated crystals is studied for the first time. It is shown that changes in the X-ray energy can change the angular region where diffraction satellites exist under conditions of total external reflection. By contrast, in the Bragg diffraction region changes in the X-ray photon energy lead to changes in the X-ray penetration depth into the crystal and redistribution of the diffracted intensity among diffraction satellites, but do not change the angular divergence between diffraction satellites on the rocking curve. It is also shown that, in X-ray diffraction on acoustically modulated crystals on a number of successive reflections, a decrease in interplanar spacing leads to an increase in the number of diffraction satellites and a redistribution of diffracted radiation between them.

Comparison Research about Wavelet and Moving Smoothing Method Applied in Denoising X-Ray Diffraction Patterns of Tibetan Medicine

2014 ◽  
Vol 577 ◽  
pp. 771-776
Author(s):  
Yuan Liu ◽  
Xin Wen Duan ◽  
Cheng Xi Hu ◽  
Hao Sun ◽  
Jian Rui Zhu
Keyword(s):  
Tibetan Medicine ◽  
Smoothing Effect ◽  
X Ray Diffraction ◽  
X Ray ◽  
Comparison Research ◽  
Modulus Maximum ◽  
Diffraction Patterns ◽  
Xrd Patterns ◽  
First Time

Comparison research for XRD patterns between Modulus Maximum denoising (marked MJ) and thresholding denoising (marked Thr) all based on wavelet analysis, and the Savitzky-Golay filter (marked SG), as well as variation of denoising effect with required parameters of SG method, was investigated for the first time. The results showed that the Thr method exhibited a good smoothing effect for mineral XRD patterns with sharp peaks, and the MJ method was more suitable for plant-based XRD patterns with broad dispersive peaks. Although the SG method with the optimized parameters possessed a higher denoising property for both the two kinds of patterns, the determination of optimized parameters was hard and needed to be specified by users.

scholarly journals Photoprotective Activity of Lichen Extracts and Isolated Compounds in Parmotrema Tinctorum

2021 ◽  
Vol 11 (5) ◽  
pp. 12653-12661
Keyword(s):  
Spectroscopic Methods ◽  
X Ray Diffraction ◽  
X Ray ◽  
First Time ◽  
Excellent Source ◽  
Parmotrema Tinctorum

Lichens are an excellent source for the discovery and development of new photoprotective compounds. However, investigation on their bioactivities remains limited, especially in Vietnam. In this study, six lichen extracts (Parmotrema poolii, P. sancti-angelii, P. tinctorum, Usnea baileyi, U. pulvinulata, U. undulata) and five isolated compounds from commonly distributed species P. tinctorum (methyl β-orcinol carboxylate (1), atranorin (2), lecanorol (3), salazinic acid (4), 1β-acetoxyhopan-3β,22-diol (5)) have been screened in vitro for their photoprotective activity. The photoprotective potential was investigated by determination of their absolute (UV-PF, c, UVA-PF) and relative indexes (SUI, ISP). The structures of isolated compounds were elucidated by spectroscopic methods and confirmed by X-ray diffraction. The results showed that P. poolii, P. sancti-angelii, P. tinctorum, U. baileyi, U. undulata, and compounds of methyl β-orcinol carboxylate (1) and salazinic acid (4) acted as strict UVB filters, and their photoprotective activities are comparable to that of the commercial UVB filter (4-methylbenzylidene camphor). Meanwhile, U. pulvinulata acted as a UVA booster. Compound (3) presented characteristics of a UVA filter, (2) protected well from both UVA and UVB while (5) exhibited a weak photoprotective activity. For the first time, this work successfully extracted several highly potential solar photoprotective compounds from Vietnam's lichens.

Sem and X-Ray Analysis of Renal and Biliary Calculi

1976 ◽  
Vol 34 ◽  
pp. 306-307
Author(s):  
R. J. Narconis ◽  
G. L. Johnson
Keyword(s):  
Chemical Constituents ◽  
Natural State ◽  
X Ray Diffraction ◽  
Chemical Methods ◽  
X Ray ◽  
Additional Dimension ◽  
Biliary Calculi ◽  
Calculus Formation ◽  
Scanning Electron

Analysis of the constituents of renal and biliary calculi may be of help in the management of patients with calculous disease. Several methods of analysis are available for identifying these constituents. Most common are chemical methods, optical crystallography, x-ray diffraction, and infrared spectroscopy. The application of a SEM with x-ray analysis capabilities should be considered as an additional alternative.A scanning electron microscope equipped with an x-ray “mapping” attachment offers an additional dimension in its ability to locate elemental constituents geographically, and thus, provide a clue in determination of possible metabolic etiology in calculus formation. The ability of this method to give an undisturbed view of adjacent layers of elements in their natural state is of advantage in determining the sequence of formation of subsequent layers of chemical constituents.

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